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Sample records for advanced ultra supercritical

  1. Cast Alloys for Advanced Ultra Supercritical Steam Turbines

    SciTech Connect

    G. R. Holcomb, P. Wang, P. D. Jablonski, and J. A. Hawk,

    2010-05-01

    The proposed steam inlet temperature in the Advanced Ultra Supercritical (A-USC) steam turbine is high enough (760 °C) that traditional turbine casing and valve body materials such as ferritic/martensitic steels will not suffice due to temperature limitations of this class of materials. Cast versions of several traditionally wrought Ni-based superalloys were evaluated for use as casing or valve components for the next generation of industrial steam turbines. The full size castings are substantial: 2-5,000 kg each half and on the order of 100 cm thick. Experimental castings were quite a bit smaller, but section size was retained and cooling rate controlled to produce equivalent microstructures. A multi-step homogenization heat treatment was developed to better deploy the alloy constituents. The most successful of these cast alloys in terms of creep strength (Haynes 263, Haynes 282, and Nimonic 105) were subsequently evaluated by characterizing their microstructure as well as their steam oxidation resistance (at 760 and 800 °C).

  2. Ultra supercritical steamside oxidation

    SciTech Connect

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Ziomek-Moroz, Margaret

    2005-01-01

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions, Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  3. Ultra supercritical steamside oxidation

    SciTech Connect

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Ziomek-Moroz, M.; Alman, David A.; Ochs, Thomas L.

    2004-01-01

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions, which are part of the U.S. Department of Energy's Vision 21 goals. Most current coal power plants in the U.S. operate at a maximum steam temperature of 538 C. However, new supercritical plants worldwide are being brought into service with steam temperatures of up to 620 C. Vision 21 goals include steam temperatures of up to 760 C. This research examines the steamside oxidation of advanced alloys for use in USC systems. Emphasis is placed on alloys for high- and intermediate-pressure turbine sections. Initial results of this research are presented.

  4. Ultra Supercritical Steamside Oxidation

    SciTech Connect

    Holcomb, Gordon R.; Cramer, Stephen D.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Ziomek-Moroz, Malgorzata

    2005-01-01

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions, which are goals of the U.S. Department of Energy's Advanced Power Systems Initiatives. Most current coal power plants in the U.S. operate at a maximum steam temperature of 538 C. However, new supercritical plants worldwide are being brought into service with steam temperatures of up to 620 C. Current Advanced Power Systems goals include coal generation at 60% efficiency, which require steam temperatures of up to 760 C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections. Initial results of this research are presented.

  5. Cast Alloys for Advanced Ultra Supercritical Steam Turbines

    SciTech Connect

    G. R. Holcomb, P. D. Jablonski, and P. Wang

    2010-10-01

    Develop advanced coal-based power systems capable of 45–50 % efficiency at <$1,000/kW (in 2002 dollars). Develop technologies for capture and sequestration of CO2 that result in: • <10% increase in the cost of electricity in an IGCC-based plant • <35% increase in the cost of electricity for pulverized coal boilers Demonstrate coal-based energy plants that offer near-zero emissions (including CO2) with multiproduct production

  6. Modeling Creep-Fatigue-Environment Interactions in Steam Turbine Rotor Materials for Advanced Ultra-supercritical Coal Power Plants

    SciTech Connect

    Shen, Chen

    2014-04-01

    The goal of this project is to model creep-fatigue-environment interactions in steam turbine rotor materials for advanced ultra-supercritical (A-USC) coal power Alloy 282 plants, to develop and demonstrate computational algorithms for alloy property predictions, and to determine and model key mechanisms that contribute to the damages caused by creep-fatigue-environment interactions.

  7. Safe Use Limits for Advanced Ferritic Steels in Ultra-Supercritical Power Boilers.

    SciTech Connect

    Swindeman, RW

    2003-11-03

    In 2000, a Cooperative Research and Development Agreement (CRADA) was undertaken between the Oak Ridge National Laboratory (ORNL) and the Babcock & Wilcox Company to examine the databases for advanced ferritic steels and determine the safe limits for operation in supercritical steam power boilers. The materials of interest included the vanadium-modified 9-12% Cr steels with 1-2% Mo or W. The first task involved a review of pertinent information and the down-selection of a steel of special interest. The long-time database for 9Cr-1Mo-V steel was found to be most satisfactory for the examinations, and this steel was taken to be representative of the group. The second task involved the collection of aged and service exposed samples for metallurgical and mechanical testing. Here, aged samples to 75,000 hours, laboratory-tested samples to 83,000 hours, and service-exposed sample with up to 143,000 hours exposure were collected. The third task involved mechanical testing of exposed samples. Creep-rupture testing to long times was undertaken. Variable stress and temperature testing was included. Results were compared against the prediction of damage models. These models seemed to be adequate for life prediction. The fourth task involved the metallurgical examination of exposed specimens. Changes in microstructure were compared against published information on the evolution of microstructures in 9Cr-Mo-V steels and the results were found to be consistent with expectations. The fifth task involved a survey of steam and fireside corrosion. Data from the service-exposed tubing was examined, and a literature survey was undertaken as part of an activity in support of ultra-supercritical steam boiler technology. The corrosion study indicated some concerns about long-time fireside corrosion and suggested temperature limits were needed for corrosive coal ash conditions.

  8. Microstructural evolution in advanced boiler materials for ultra-supercritical coal power plants

    NASA Astrophysics Data System (ADS)

    Wu, Quanyan

    The goal of improving the efficiency of pulverized coal powerplants has been pursued for decades. The need for greater efficiency and reduced environmental impact is pushing utilities to ultra supercritical conditions (USC), i.e. steam temperatures approaching 760°C under a stress of 35 MPa. The long-term creep strength and environmental resistance requirements imposed by these conditions are clearly beyond the capacity of the currently used ferritic steels and other conventional alloys. As part of a large DOE-funded consortium, new and existing materials based on advanced austenitic stainless steels and nickel base superalloys are being evaluated for these very demanding applications. In the present work, the nickel base superalloys of Inconel 617, CCA617, Haynes 230 and Inconel 740, and austenitic alloys Super 304H and HR6W, were evaluated on their microstructural properties over elevated temperature ageing and creep rupture conditions. The materials were aged for different lengths of time at temperatures relevant to USC applications, i.e., in the range from 700 to 800°C. The precipitation behaviors, namely of the gamma', carbides and eta phase in some conditions in nickel base superalloys, carbides in Haynes 230, Cu-rich precipitates in Super 304H and Laves phase particles in HR6W, were studied in detail using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and related analytical techniques. Particular attention has been given on the structure, morphology and compositional distinctiveness of various phases (including gamma, gamma', carbides, secondary phase precipitates, and other types of particles) and their nature, dislocation structures and other types of defects. The results were presented and discussed in light of associated changes in microhardness in the cases of aged samples, and in close reference to mechanical testing (including tensile and creep rupture tests) wherever available. Several mechanical strengthening

  9. Ultra supercritical turbines--steam oxidation

    SciTech Connect

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Ziomek-Moroz, Margaret; Alman, David E.

    2004-01-01

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions, which are goals of the U.S. Department of Energy?s Advanced Power Systems Initiatives. Most current coal power plants in the U.S. operate at a maximum steam temperature of 538?C. However, new supercritical plants worldwide are being brought into service with steam temperatures of up to 620?C. Current Advanced Power Systems goals include coal generation at 60% efficiency, which would require steam temperatures of up to 760?C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections. Initial results of this research are presented.

  10. ULTRA-SUPERCRITICAL STEAM CORROSION

    SciTech Connect

    Holcomb, G.R.; Alman, D.E.; Bullard, S.B.; Covino, B.S., Jr.; Cramer, S.D.; Ziomek-Moroz, M.

    2003-04-22

    Efficiency increases in fossil energy boilers and steam turbines are being achieved by increasing the temperature and pressure at the turbine inlets well beyond the critical point of water. To allow these increases, advanced materials are needed that are able to withstand the higher temperatures and pressures in terms of strength, creep, and oxidation resistance. As part of a larger collaborative effort, the Albany Research Center (ARC) is examining the steam-side oxidation behavior for ultrasupercritical (USC) steam turbine applications. Initial tests are being done on six alloys identified as candidates for USC steam boiler applications: ferritic alloy SAVE12, austenitic alloy Super 304H, the high Cr-high Ni alloy HR6W, and the nickel-base superalloys Inconel 617, Haynes 230, and Inconel 740. Each of these alloys has very high strength for its alloy type. Three types of experiments are planned: cyclic oxidation in air plus steam at atmospheric pressure, thermogravimetric ana lysis (TGA) in steam at atmospheric pressure, and exposure tests in supercritical steam up to 650 C (1202 F) and 34.5 MPa (5000 psi). The atmospheric pressure tests, combined with supercritical exposures at 13.8, 20.7, 24.6, and 34.5 MPa (2000, 3000, 4000, and 5000 psi) should allow the determination of the effect of pressure on the oxidation process.

  11. Materials development for ultra-supercritical boilers

    SciTech Connect

    2005-09-30

    Progress is reported on a US Department of Energy project to develop high temperature, corrosion resistant alloys for use in ultra-supercritical steam cycles. The aim is to achieve boiler operation at 1,400{sup o}F/5,000 psi steam conditions with 47% net cycle efficiency. Most ferritic steel tested such as T92 and Save 12 showed severe corrosion. Nickel-based alloys, especially IN 740 and CCA 617, showed greatest resistance to oxidation with no evidence of exfoliation. Laboratory and in-plant tests have begun. 2 figs.

  12. Ultra-Supercritical Pressure CFB Boiler Conceptual Design Study

    SciTech Connect

    Zhen Fan; Steve Goidich; Archie Robertson; Song Wu

    2006-06-30

    Electric utility interest in supercritical pressure steam cycles has revived in the United States after waning in the 1980s. Since supercritical cycles yield higher plant efficiencies than subcritical plants along with a proportional reduction in traditional stack gas pollutants and CO{sub 2} release rates, the interest is to pursue even more advanced steam conditions. The advantages of supercritical (SC) and ultra supercritical (USC) pressure steam conditions have been demonstrated in the high gas temperature, high heat flux environment of large pulverized coal-fired (PC) boilers. Interest in circulating fluidized bed (CFB) combustion, as an alternative to PC combustion, has been steadily increasing. Although CFB boilers as large as 300 MWe are now in operation, they are drum type, subcritical pressure units. With their sizes being much smaller than and their combustion temperatures much lower than those of PC boilers (300 MWe versus 1,000 MWe and 1600 F versus 3500 F), a conceptual design study was conducted herein to investigate the technical feasibility and economics of USC CFB boilers. The conceptual study was conducted at 400 MWe and 800 MWe nominal plant sizes with high sulfur Illinois No. 6 coal used as the fuel. The USC CFB plants had higher heating value efficiencies of 40.6 and 41.3 percent respectively and their CFB boilers, which reflect conventional design practices, can be built without the need for an R&D effort. Assuming construction at a generic Ohio River Valley site with union labor, total plant costs in January 2006 dollars were estimated to be $1,551/kW and $1,244/kW with costs of electricity of $52.21/MWhr and $44.08/MWhr, respectively. Based on the above, this study has shown that large USC CFB boilers are feasible and that they can operate with performance and costs that are competitive with comparable USC PC boilers.

  13. Computational Modeling and Assessment Of Nanocoatings for Ultra Supercritical Boilers

    SciTech Connect

    David W. Gandy; John P. Shingledecker

    2011-04-11

    Forced outages and boiler unavailability in conventional coal-fired fossil power plants is most often caused by fireside corrosion of boiler waterwalls. Industry-wide, the rate of wall thickness corrosion wastage of fireside waterwalls in fossil-fired boilers has been of concern for many years. It is significant that the introduction of nitrogen oxide (NOx) emission controls with staged burners systems has increased reported waterwall wastage rates to as much as 120 mils (3 mm) per year. Moreover, the reducing environment produced by the low-NOx combustion process is the primary cause of accelerated corrosion rates of waterwall tubes made of carbon and low alloy steels. Improved coatings, such as the MCrAl nanocoatings evaluated here (where M is Fe, Ni, and Co), are needed to reduce/eliminate waterwall damage in subcritical, supercritical, and ultra-supercritical (USC) boilers. The first two tasks of this six-task project-jointly sponsored by EPRI and the U.S. Department of Energy (DE-FC26-07NT43096)-have focused on computational modeling of an advanced MCrAl nanocoating system and evaluation of two nanocrystalline (iron and nickel base) coatings, which will significantly improve the corrosion and erosion performance of tubing used in USC boilers. The computational model results showed that about 40 wt.% is required in Fe based nanocrystalline coatings for long-term durability, leading to a coating composition of Fe-25Cr-40Ni-10 wt.% Al. In addition, the long term thermal exposure test results further showed accelerated inward diffusion of Al from the nanocrystalline coatings into the substrate. In order to enhance the durability of these coatings, it is necessary to develop a diffusion barrier interlayer coating such TiN and/or AlN. The third task 'Process Advanced MCrAl Nanocoating Systems' of the six-task project jointly sponsored by the Electric Power Research Institute, EPRI and the U.S. Department of Energy (DE-FC26-07NT43096)- has focused on processing of

  14. Thermodynamic and economic analysis of a 900 MW ultra-supercritical power unit

    NASA Astrophysics Data System (ADS)

    łukowicz, Henryk; Dykas, Sławomir; Rulik, Sebastian; Stępczyńska, Katarzyna

    2011-12-01

    The paper presents a thermal-economic analysis of different variants of a hard coal-fired 900 MW ultra-supercritical power unit. The aim of the study was to determine the effect of the parameters of live and reheated steam on the basic thermodynamic and economic indices of the thermal cycle. The subject of the study was the cycle configuration proposed as the "initial thermal cycle structure" during the completion of the project "Advanced Technologies for Energy Generation" with the live and reheated steam parameters of 650/670 °C. At the same time, a new concept of a thermal cycle for ultra-supercritical parameters with live and reheated steam temperature of 700/720 °C was suggested. The analysis of the ultra-supercritical unit concerned a variant with a single and double steam reheat. All solutions presented in the paper were subject to a detailed thermodynamic analysis, as well as an economic one which also included CO2emissions charges. The conducted economic analysis made it possible to determine the maximum value of investment expenditures at which given solutions are profitable.

  15. Superalloys for ultra supercritical steam turbines--oxidation behavior

    SciTech Connect

    Holcomb, G.R.

    2008-09-01

    Goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include power generation from coal at 60% efficiency, which requires steam conditions of up to 760 °C and 340 atm, so called ultra-supercritical (USC) steam conditions. One of the important materials performance considerations is steam-side oxidation resistance. Evaporation of protective chromia scales is expected to be a primary corrosion mechanism under USC conditions. A methodology to calculate Cr evaporation rates from chromia scales with cylindrical geometries was developed that allows for the effects of CrO2(OH)2 saturation within the gas phase. This approach was combined with Cr diffusion calculations within the alloy (with a constant flux of Cr leaving the alloy from evaporation) to predict Cr concentration profiles as a function of exposure time and to predict the time until the alloy surface concentration of Cr reaches zero. This time is a rough prediction of the time until breakaway oxidation. A hypothetical superheater tube, steam pipe, and high pressure turbine steam path was examined. At the highest temperatures and pressures, the time until breakaway oxidation was predicted to be quite short for the turbine blade, and of concern within the steam pipe and the higher temperature portions of the superheater tube. The predicted time until breakaway oxidation increases dramatically with decreases in temperature and total pressure. Possible mitigation techniques were discussed, including those used in solid oxide fuel cell metallic interconnects (lowering the activity of Cr in the oxide scale by adding Mn to the alloy), and thermal barrier coating use on high pressure turbine blades for both erosion and chromia evaporation protection.

  16. Lessons from the past: materials-related issues in an ultra-supercritical boiler at Eddystone plant

    SciTech Connect

    Henry, J.; Zhou, G.; Ward, T.

    2007-07-01

    Major research efforts have made progress toward the development of coal-fired ultra-supercritical steam generators that will operate at efficiencies approaching 50% based on HHV. A component test facility designed to evaluate operation of major steam generator components at 700{degree}C (1292{degree}F) will soon be operational in Germany, and the first demonstration plant incorporating advanced ultra-supercritical technology could be constructed as soon as the year 2010. The question posed by those who will be responsible for the operation of these new ultra-supercritical power plants is obvious: will they perform reliably under the conditions of flexible operation that are likely to be imposed by modern de-regulated markets? The real intent of this question is more subtle: do the materials and methods of construction exist to build these advanced coal-fired boilers. In large part, the answer to that question lies in a US power plant located not far from the Philadelphia airport. The plant is Exelon's Eddystone plant. The steam generator for Unit I at that plant has operated successfully for over 44 years at steam conditions more advanced than any other coal-fired unit in operation today. This paper reviews salient features of the operating history of Eddystone 1, focussing on the materials-related problems that forced a modest retreat from the original and unprecedented design conditions, emphasizing the record of many years of reliable operation at aggressive steam conditions. It then discusses a few of the more significant materials-related issues involved in operating a steam generator at Eddystone-like conditions as a basis for arguing that there exists today the materials and manufacturing understanding necessary to construct an advanced ultra-supercritical unit that will operate efficiently and reliably.

  17. Computation Modeling and Assessment of Nanocoatings for Ultra Supercritical Boilers

    SciTech Connect

    J. Shingledecker; D. Gandy; N. Cheruvu; R. Wei; K. Chan

    2011-06-21

    Forced outages and boiler unavailability of coal-fired fossil plants is most often caused by fire-side corrosion of boiler waterwalls and tubing. Reliable coatings are required for Ultrasupercritical (USC) application to mitigate corrosion since these boilers will operate at a much higher temperatures and pressures than in supercritical (565 C {at} 24 MPa) boilers. Computational modeling efforts have been undertaken to design and assess potential Fe-Cr-Ni-Al systems to produce stable nanocrystalline coatings that form a protective, continuous scale of either Al{sub 2}O{sub 3} or Cr{sub 2}O{sub 3}. The computational modeling results identified a new series of Fe-25Cr-40Ni with or without 10 wt.% Al nanocrystalline coatings that maintain long-term stability by forming a diffusion barrier layer at the coating/substrate interface. The computational modeling predictions of microstructure, formation of continuous Al{sub 2}O{sub 3} scale, inward Al diffusion, grain growth, and sintering behavior were validated with experimental results. Advanced coatings, such as MCrAl (where M is Fe, Ni, or Co) nanocrystalline coatings, have been processed using different magnetron sputtering deposition techniques. Several coating trials were performed and among the processing methods evaluated, the DC pulsed magnetron sputtering technique produced the best quality coating with a minimum number of shallow defects and the results of multiple deposition trials showed that the process is repeatable. scale, inward Al diffusion, grain growth, and sintering behavior were validated with experimental results. The cyclic oxidation test results revealed that the nanocrystalline coatings offer better oxidation resistance, in terms of weight loss, localized oxidation, and formation of mixed oxides in the Al{sub 2}O{sub 3} scale, than widely used MCrAlY coatings. However, the ultra-fine grain structure in these coatings, consistent with the computational model predictions, resulted in accelerated Al

  18. Advanced Supercritical Carbon Dioxide Brayton Cycle Development

    SciTech Connect

    Anderson, Mark; Sienicki, James; Moisseytsev, Anton; Nellis, Gregory; Klein, Sanford

    2015-10-21

    Fluids operating in the supercritical state have promising characteristics for future high efficiency power cycles. In order to develop power cycles using supercritical fluids, it is necessary to understand the flow characteristics of fluids under both supercritical and two-phase conditions. In this study, a Computational Fluid Dynamic (CFD) methodology was developed for supercritical fluids flowing through complex geometries. A real fluid property module was implemented to provide properties for different supercritical fluids. However, in each simulation case, there is only one species of fluid. As a result, the fluid property module provides properties for either supercritical CO2 (S-CO2) or supercritical water (SCW). The Homogeneous Equilibrium Model (HEM) was employed to model the two-phase flow. HEM assumes two phases have same velocity, pressure, and temperature, making it only applicable for the dilute dispersed two-phase flow situation. Three example geometries, including orifices, labyrinth seals, and valves, were used to validate this methodology with experimental data. For the first geometry, S-CO2 and SCW flowing through orifices were simulated and compared with experimental data. The maximum difference between the mass flow rate predictions and experimental measurements is less than 5%. This is a significant improvement as previous works can only guarantee 10% error. In this research, several efforts were made to help this improvement. First, an accurate real fluid module was used to provide properties. Second, the upstream condition was determined by pressure and density, which determines supercritical states more precise than using pressure and temperature. For the second geometry, the flow through labyrinth seals was studied. After a successful validation, parametric studies were performed to study geometric effects on the leakage rate. Based on these parametric studies, an optimum design strategy for the see

  19. Generic chiral method development in supercritical fluid chromatography and ultra-performance supercritical fluid chromatography.

    PubMed

    De Klerck, Katrijn; Vander Heyden, Yvan; Mangelings, Debby

    2014-10-10

    The development of chiral separation methods in pharmaceutical industry is often a very tedious, labour intensive and expensive process. A trial-and-error approach remains frequently used, given the unpredictable nature of enantioselectivity. To speed-up this process and to maximize the efficiency of method development, a generic chiral separation strategy for SFC is proposed in this study. To define such strategy, the effect of different chromatographic parameters on the enantioselectivity is investigated and evaluated. Subsequently, optimization steps are defined to improve a chiral separation in terms of resolution, analysis time, etc. or to induce separation when initially not obtained. The defined strategy proved its applicability and efficiency with the successful separation of a novel 20-compound test set. In a second stage, the method transfer from a conventional to an ultra-performance SFC system is investigated for the screening step of the separation strategy. The method transfer proved to be very easy and straightforward. Similar enantioresolution values, but slightly shorter analysis times were obtained on the ultra-performance equipment. Nevertheless, even more benefit may be expected in ultra-performance SFC when customized sub-2 μm chiral stationary phases will become available. PMID:24953426

  20. Feasibility of ultra high performance supercritical neat carbon dioxide chromatography at conventional pressures.

    PubMed

    Sarazin, Cédric; Thiébaut, Didier; Sassiat, Patrick; Vial, Jérôme

    2011-10-01

    The implementation of columns packed with sub-2 μm particles in supercritical fluid chromatography (SFC) is described using neat carbon dioxide as the mobile phase. A conventional supercritical fluid chromatograph was slightly modified to reduce extra column band broadening. Performances of a column packed with 1.8 μm C18-bonded silica particles in SFC using neat carbon dioxide as the mobile phase were compared with results obtained in ultra high performance liquid chromatography (UHPLC) using a dedicated chromatograph. As expected and usual in SFC, higher linear velocities than in UHPLC must be applied in order to reach optimal efficiency owing to higher diffusion coefficient of solutes in the mobile phase; similar numbers of theoretical plates were obtained with both techniques. Very fast separations of hydrocarbons are presented using two different alkyl-bonded silica columns. PMID:21898804

  1. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-08-01

    The program objective is to generate ultra-fine catalyst particles (20 to 400 {Angstrom} in size) and quantify their potential for improving coal dissolution in the solubilization stage of two-stage catalytic-catalytic liquefaction systems. It has been shown that catalyst activity increases significantly with decreasing particle size for particle sizes in the submicron range. Ultra-fine catalyst particle generation will be accomplished using a novel two-step process. First, the severe conditions produced by a supercritical fluid (e.g., supercritical H{sub 2}O or CO{sub 2}) will be used to dissolve suitable catalyst compounds (e.g., Fe{sub 2}O{sub 3}, FeS{sub 2}, and/or Fe(CO){sub 5}). Sulfur containing compounds may be added to the supercritical solvent during catalyst dissolution to enhance the catalytic activity of the resulting ultra-fine, iron based, catalyst particles.

  2. Computational Modeling and Assessment Of Nanocoatings for Ultra Supercritical Boilers

    SciTech Connect

    Gandy, David W.; Shingledecker, John P.

    2011-05-11

    Coal-fired power plants are a significant part of the nation's power generating capacity, currently accounting for more than 55% of the country's total electricity production. Extending the reliable lifetimes of fossil fired boiler components and reducing the maintenance costs are essential for economic operation of power plants. Corrosion and erosion are leading causes of superheater and reheater boiler tube failures leading to unscheduled costly outages. Several types of coatings and weld overlays have been used to extend the service life of boiler tubes; however, the protection afforded by such materials was limited approximately one to eight years. Power companies are more recently focused in achieving greater plant efficiency by increasing steam temperature and pressure into the advanced-ultrasupercritical (A-USC) condition with steam temperatures approaching 760°C (1400°F) and operating pressures in excess of 35MPa (5075 psig). Unfortunately, laboratory and field testing suggests that the resultant fireside environment when operating under A-USC conditions can potentially cause significant corrosion to conventional and advanced boiler materials1-2. In order to improve reliability and availability of fossil fired A-USC boilers, it is essential to develop advanced nanostructured coatings that provide excellent corrosion and erosion resistance without adversely affecting the other properties such as toughness and thermal fatigue strength of the component material.

  3. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1992-05-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period focused on assembling the supercritical particle generation/collection system. Effort was applied to constructing a shakedown testing plan also.

  4. Steam Oxidation and Chromia Evaporation in Ultra-Supercritical Steam Boilers and Turbines

    SciTech Connect

    Gordon H. Holcomb

    2009-01-01

    U.S. Department of Energy’s goals include power generation from coal at 60% efficiency, which requires steam conditions of up to 760 °C and 340 atm, so-called ultra-supercritical (USC) conditions. Evaporation of protective chromia scales is expected to be a primary corrosion mechanism. A methodology to calculate Cr evaporation rates from chromia scales was developed and combined with Cr diffusion calculations within the alloy (with a constant flux of Cr leaving the alloy from evaporation) to predict Cr concentration profiles and to predict the time until breakaway oxidation. At the highest temperatures and pressures, the time until breakaway oxidation was predicted to be quite short for the turbine blade, and of concern within the steam pipe and the higher temperature portions of the superheater tube. Alloy additions such as Ti may allow for a reduction in evaporation rate with time, mitigating the deleterious effects of chromia evaporation.

  5. Advanced Thermal Storage for Central Receivers with Supercritical Coolants

    SciTech Connect

    Kelly, Bruce D.

    2010-06-15

    The principal objective of the study is to determine if supercritical heat transport fluids in a central receiver power plant, in combination with ceramic thermocline storage systems, offer a reduction in levelized energy cost over a baseline nitrate salt concept. The baseline concept uses a nitrate salt receiver, two-tank (hot and cold) nitrate salt thermal storage, and a subcritical Rankine cycle. A total of 6 plant designs were analyzed, as follows: Plant Designation Receiver Fluid Thermal Storage Rankine Cycle Subcritical nitrate salt Nitrate salt Two tank nitrate salt Subcritical Supercritical nitrate salt Nitrate salt Two tank nitrate salt Supercritical Low temperature H2O Supercritical H2O Two tank nitrate salt Supercritical High temperature H2O Supercritical H2O Packed bed thermocline Supercritical Low temperature CO2 Supercritical CO2 Two tank nitrate salt Supercritical High temperature CO2 Supercritical CO2 Packed bed thermocline Supercritical Several conclusions have been drawn from the results of the study, as follows: 1) The use of supercritical H2O as the heat transport fluid in a packed bed thermocline is likely not a practical approach. The specific heat of the fluid is a strong function of the temperatures at values near 400 °C, and the temperature profile in the bed during a charging cycle is markedly different than the profile during a discharging cycle. 2) The use of supercritical CO2 as the heat transport fluid in a packed bed thermocline is judged to be technically feasible. Nonetheless, the high operating pressures for the supercritical fluid require the use of pressure vessels to contain the storage inventory. The unit cost of the two-tank nitrate salt system is approximately $24/kWht, while the unit cost of the high pressure thermocline system is nominally 10 times as high. 3) For the supercritical fluids, the outer crown temperatures of the receiver tubes are in the range of 700 to 800 °C. At temperatures of 700 °C and above

  6. An improved classification of stationary phases for ultra-high performance supercritical fluid chromatography.

    PubMed

    West, Caroline; Lemasson, Elise; Bertin, Sophie; Hennig, Philippe; Lesellier, Eric

    2016-04-01

    Supercritical fluid chromatography (SFC) has recently benefited of new instrumentation, together with the availability of many ultra-high performance columns (sub -2μm fully porous particles or sub -3μm superficially porous particles), rendering it more attractive than ever. Most of these columns commonly used in SFC were initially developed for HPLC use, with an increasing number of stationary phases specifically designed for SFC. While the availability of different stationary phase chemistries is an advantage to achieve successful SFC separations, selecting a column for method development remains difficult. For this reason, we have previously developed a classification of stationary phases dedicated to SFC use. It is based on linear solvation energy relationships (LSER) with Abraham descriptors (for neutral species). While current interest in SFC is strong in the pharmaceutical industry, the need to take account of interactions occurring with ionisable species is pressing. We have previously shown how a modified version of the solvation parameter model, adapted to take account of ionic and ionizable species, could be applied to the characterization of SFC systems. In the present paper, based on this modified LSER model, and on the analysis of 109 neutral and ionisable species, we propose an improved classification of 31 ultra-high performance stationary phases to facilitate method development with SFC. PMID:26920664

  7. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-09-01

    The program objective is to generate ultra-fine catalyst particles (20 to 400 {Angstrom} in size) and quantify their potential for improving coal dissolution in the solubilization stage of two-stage catalytic-catalytic liquefaction systems. In the first quarterly report for this program the concept behind our approach was detailed, the structure of the program was presented, key technical issues were identified, preliminary designs were outlined, and technical progress was discussed. All progress made during the second quarter of this program related to experiment design of the proposed supercritical expansion technique for generating ultra-fine, iron compound, catalyst particles. This second quarterly report, therefore, presents descriptions of the final designs for most system components; diagnostic approaches and designs for determining particles size and size distributions, and the composition of the pre-expansion supercritical solution; and the overall technique progress made during this reporting period. 6 refs., 15 figs., 1 tab.

  8. Ion Pair Asociation in Ultra Supercritical Aqueous Environments: Successful Interplay between Conductance Experiment, Theory and Molecular Simulation.

    SciTech Connect

    Chialvo, Ariel A; Gruszkiewicz, Miroslaw {Mirek} S; Cole, David R

    2010-01-01

    We discuss the interplay between theory, molecular simulation and electric conductance experiments as an important tool for the extraction of ion-pair interaction potentials to make possible the bridging of the density gap between the lowest experimentally attainable conductance measurement and the theoretically reachable zero-density limit of the ion-pair association constant. Then, we predict the density dependence of the Na+!Cl! pair association constant in ultra supercritical steam environments by constraint molecular dynamics simulation over state conditions relevant to the new generation of ultra-supercritical steam power plants. Finally, we draw attention to relevant modeling challenges associated to the behavior of these systems around the zero-density limit and discuss ways to overcome them.

  9. [Determination of seven additives in polymer products by ultra performance supercritical fluid chromatography].

    PubMed

    Zhang, Yun; Du, Zhenxia

    2014-01-01

    A method for rapid determination of seven commonly used additives in polymer products by ultra performance supercritical fluid chromatography (UPSFC)-photodiode array detector (PDA) was developed. In this experiment, the detection wavelength was set at 220 nm. After the important parameters of UPSFC, such as the diluting solvent, mobile phase additive, column temperature, automatic back pressure regulator (ABPR) and flow rate were investigated, the optimized conditions were acquired as follows: n-hexane/isopropanol (1/1, v/v) was chosen as the diluting solvent, the mixture of methanol/acetonitrile (1/1, v/v) as the mobile phase additive, 2 mL/min as the flow rate, 50 degrees C as the column temperature, 12.41 - 13.79 MPa as the ABPR. Under these conditions, seven additives were separated in 5 min, and full baseline separation was achieved. The real sample was pretreated by microwave-assisted extraction (MAE) and analyzed by UPSFC-PDA. The seven additives can be detected with the recoveries of 69.9% - 118.9%, and the relative standard deviations (RSDs, n = 9) were less than 10%. This method is simple, fast with good selectivity and suitable for the analysis of the additives in polymer products. PMID:24783869

  10. Ultra-Low NOx Advanced Vortex Combustor

    SciTech Connect

    Edmonds, R.G.; Steele, R.C.; Williams, J.T.; Straub, D.L.; Casleton, K.H.; Bining, Avtar

    2006-05-01

    An ultra lean-premixed Advanced Vortex Combustor (AVC) has been developed and tested. The natural gas fueled AVC was tested at the U.S. Department of Energy’s National Energy Technology Laboratory (USDOE NETL) test facility in Morgantown (WV). All testing was performed at elevated pressures and inlet temperatures and at lean fuel-air ratios representative of industrial gas turbines. The improved AVC design exhibited simultaneous NOx/CO/UHC emissions of 4/4/0 ppmv (all emissions are at 15% O2 dry). The design also achieved less than 3 ppmv NOx with combustion efficiencies in excess of 99.5%. The design demonstrated tremendous acoustic dynamic stability over a wide range of operating conditions which potentially makes this approach significantly more attractive than other lean premixed combustion approaches. In addition, a pressure drop of 1.75% was measured which is significantly lower than conventional gas turbine combustors. Potentially, this lower pressure drop characteristic of the AVC concept translates into overall gas turbine cycle efficiency improvements of up to one full percentage point. The relatively high velocities and low pressure drops achievable with this technology make the AVC approach an attractive alternative for syngas fuel applications.

  11. Ultra-high performance supercritical fluid chromatography of lignin-derived phenols from alkaline cupric oxide oxidation.

    PubMed

    Sun, Mingzhe; Lidén, Gunnar; Sandahl, Margareta; Turner, Charlotta

    2016-08-01

    Traditional chromatographic methods for the analysis of lignin-derived phenolic compounds in environmental samples are generally time consuming. In this work, an ultra-high performance supercritical fluid chromatography method with a diode array detector for the analysis of major lignin-derived phenolic compounds produced by alkaline cupric oxide oxidation was developed. In an analysis of a collection of 11 representative monomeric lignin phenolic compounds, all compounds were clearly separated within 6 min with excellent peak shapes, with a limit of detection of 0.5-2.5 μM, a limit of quantification of 2.5-5.0 μM, and a dynamic range of 5.0-2.0 mM (R(2) > 0.997). The new ultra-high performance supercritical fluid chromatography method was also applied for the qualitative and quantitative analysis of lignin-derived phenolic compounds obtained upon alkaline cupric oxide oxidation of a commercial humic acid. Ten out of the previous eleven model compounds could be quantified in the oxidized humic acid sample. The high separation power and short analysis time obtained demonstrate for the first time that supercritical fluid chromatography is a fast and reliable technique for the analysis of lignin-derived phenols in complex environmental samples. PMID:27452148

  12. Ultra high efficiency/low pressure supercritical fluid chromatography with superficially porous particles for triglyceride separation.

    PubMed

    Lesellier, E; Latos, A; de Oliveira, A Lopes

    2014-01-31

    This paper reports the development of the separation of vegetable oil triglycerides (TG) in supercritical chromatography (SFC), using superficially porous particles (SPPs). The SPP, having a small diameter (2-3μm), provide a higher theoretical plate number (N), which allows to improve separation of critical pairs of compounds. However, compared to fully porous particles of larger diameter (5μm), the pressure drop is also increased. Fortunately, supercritical fluids have a low viscosity, which allows coupling several columns to achieve high N values, while maintaining flow rate above 1ml/min, ensuring a ultra high efficiency (UHE) at low pressure (LP) (below 40MPa), with regards to the one reached with liquid and sub-two micron particles (around 100MPa). The use of two detector systems (UV and ELSD) connected in series to the UHE-LP-SFC system provides complementary responses, due to their specific detection principles. Working in a first part with three coupled Kinetex C18 columns (45cm total length), the effect of modifier nature and percentage were studied with two reference oils, argan and rapeseed, chosen for their different and well-known TG composition. The analytical method was developed from previous studies performed with fully porous particles (FPP). Optimized conditions with three Kinetex were as follows: 17°C, 12% of ACN/MeOH (90/10; v/v). With these conditions, and by using an increased length of Kinetex C18 column (60cm), another additional column was selected from ten different commercial SPP C18 bonded phases, by applying a Derringer function on varied parameters: theoretical plate number (TPN), separation index (SI) for critical pairs of peaks (the peaks of compounds difficult to separate due to subtle structural differences), the analysis duration, and the total peak number. This function normalizes the values of any parameters, between 0 and 1, from the worst value to the better, allowing to take account of various parameters in the final

  13. Advanced Combustion

    SciTech Connect

    Holcomb, Gordon R.

    2013-03-11

    The activity reported in this presentation is to provide the mechanical and physical property information needed to allow rational design, development and/or choice of alloys, manufacturing approaches, and environmental exposure and component life models to enable oxy-fuel combustion boilers to operate at Ultra-Supercritical (up to 650{degrees}C & between 22-30 MPa) and/or Advanced Ultra-Supercritical conditions (760{degrees}C & 35 MPa).

  14. Hydrodynamic analysis and calculation of metal temperature distribution in spiral water wall of ultra supercritical tower boiler

    NASA Astrophysics Data System (ADS)

    Shen, Chengwu; Yang, Dong; Yao, Danhua; Zhu, Yufeng; Xu, Xueyuan

    2013-07-01

    In this paper, the spiral water wall system of a 1000MW ultra supercritical tower boiler is simplified as a network system, consisting of circuits, pressure grids and connecting tubes. The establishment of the mathematical model for calculating the mass flux distribution and metal temperature in water wall is based on the mass, momentum and energy conservation equations. The water wall flow distribution and temperature profile of the boiler were computed. The result shows that the differences of outlet temperature and mass flux are small in spiral tube water wall at BMCR, 75%BMCR load and 40%BMCR load. The metal temperatures are all in the allowable ranger.

  15. Advanced Computational Thermal Studies and their Assessment for Supercritical-Pressure Reactors (SCRs)

    SciTech Connect

    D. M. McEligot; J. Y. Yoo; J. S. Lee; S. T. Ro; E. Lurien; S. O. Park; R. H. Pletcher; B. L. Smith; P. Vukoslavcevic; J. M. Wallace

    2009-04-01

    The goal of this laboratory / university collaboration of coupled computational and experimental studies is the improvement of predictive methods for supercritical-pressure reactors. The general objective is to develop supporting knowledge needed of advanced computational techniques for the technology development of the concepts and their safety systems.

  16. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ particle generation by rapid expansion of supercritical fluid solutions. Final technical report

    SciTech Connect

    Not Available

    1994-05-01

    The research conducted by Textron Defense Systems (TDS) represents a potential new and innovative concept for dispersed coal liquefaction. The technical approach is generation of ultra-fine catalyst particles from supercritical solutions by rapid expansion of either catalyst only, or mixtures of catalyst and coal material in supersaturated solvents. The process of rapid expansion of supercritical fluid solutions was developed at Battelle`s Pacific Northwest Laboratories for the intended purpose of providing a new analytical technique for characterizing supercritical fluids. The concept forming the basis of this research is that ultra-fine particles can be generated from supercritical solutions by rapid expansion of either catalyst or catalyst/coal-material mixtures in supersaturated solvents, such as carbon dioxide or water. The focal point of this technique is the rapid transfer of low vapor pressure solute (i.e., catalyst), dissolved in the supercritical fluid solvent, to the gas phase as the solution is expanded through an orifice. The expansion process is characterized by highly nonequilibrium conditions which cause the solute to undergo extremely rapid supersaturation with respect to the solvent, leading to nucleation and particle growth resulting in nanometer size catalyst particles. A supercritical expansion system was designed and built by TDS at their Haverhill facility.

  17. Design considerations of advanced supercritical low drag suction airfoils

    NASA Technical Reports Server (NTRS)

    Pfenninger, W.; Reed, H. L.; Dagenhart, J. R.

    1980-01-01

    Supercritical low drag suction laminar flow airfoils were laid out for shock-free flow at design freestream Mach = 0.76, design lift coefficient = 0.58, and t/c = 0.13. The design goals were the minimization of suction laminarization problems and the assurance of shock-free flow at freestream Mach not greater than design freestream Mach (for design lift coefficient) as well as at lift coefficient not greater than design lift coefficient (for design freestream Mach); this involved limiting the height-to-length ratio of the supersonic zone at design to 0.35. High design freestream Mach numbers result with extensive supersonic flow (over 80% of the chord) on the upper surface, with a steep Stratford-type rear pressure rise with suction, as well as by carrying lift essentially in front- and rear-loaded regions of the airfoil with high static pressures on the carved out front and rear lower surface.

  18. Comparison of ultra-high performance supercritical fluid chromatography and ultra-high performance liquid chromatography for the analysis of pharmaceutical compounds.

    PubMed

    Grand-Guillaume Perrenoud, Alexandre; Veuthey, Jean-Luc; Guillarme, Davy

    2012-11-30

    Currently, columns packed with sub-2 μm particles are widely employed in liquid chromatography but are scarcely used in supercritical fluid chromatography. The goal of the present study was to compare the performance, possibilities and limitations of both ultra-high performance liquid chromatography (UHPLC) and ultra-high performance supercritical fluid chromatography (UHPSFC) using columns packed with sub-2 μm particles. For this purpose, a kinetic evaluation was first performed, and van Deemter curves and pressure plots were constructed and compared for columns packed with hybrid silica stationary phases composed of 1.7 and 3.5 μm particles. As expected, the kinetic performance of the UHPSFC method was significantly better than that of the UHPLC. Indeed, the h(min) values were in the same range with both strategies and were between 2.2 and 2.8, but u(opt) was increased by a factor of >4 in UHPSFC conditions. Another obvious advantage of UHPSFC over UHPLC is related to the generated backpressure, which is significantly lower in the presence of a supercritical or subcritical fluid. However, the upper pressure limit of the UHPSFC system was only ∼400 bar vs. ∼1000 bar in the UHPLC system, which prevents the use of highly organic mobile phases at high flow rates in UHPSFC. Second, the impact of reducing the particle size (from 3.5 to 1.7 μm) was evaluated in both UHPLC and UHPSFC conditions. The effect of frictional heating on the selectivity was demonstrated in UHPLC and that of fluid density or decompression cooling was highlighted in UHPSFC. However, in both cases, a change in selectivity was observed for only a limited number of compounds. Third, various types of column chemistries packed with 1.7 μm particles were evaluated in both UHPLC and UHPSFC conditions using a model mixture of acidic, neutral and basic compounds. It has been shown that more drastic changes in selectivity were obtained using UHPSFC columns compared to those obtained by changing

  19. Supercritical fluid extraction of isoflavones from biological samples with ultra-fast high-performance liquid chromatography/mass spectrometry.

    PubMed

    Klejdus, Borivoj; Lojková, Lea; Lapcík, Oldrich; Koblovská, Radka; Moravcová, Jitka; Kubán, Vlastimil

    2005-08-01

    An efficient method of modifier addition for supercritical fluid extraction (SFE) of polar isoflavones was developed and yielded extraordinarily high recoveries. To find the optimal extraction conditions, a temperature and pressure optimization and modifier impact study was performed in naturally contaminated and spiked samples. Ultra-fast high-performance liquid chromatography/mass spectrometry (HPLC/MS) was used for the determination of isoflavones on an Atlantis dC18 high-speed reversed phase chromatographic column (20 x 2.1 mm, 3 microm particle size). A newly elaborated supercritical fluid extraction (SFE) procedure allowed more accurate (< 5%) and precise (< 4-7%) determination of isoflavones in biological materials. The HPLC/MS method significantly reduced analysis time with simultaneous improvement of sensitivity and detection limits. The on-column limits of detection LOD (S/N = 3) for isoflavone glycosides (daidzin, genistin, glycitin, ononin, and sissotrin) were 1.3-3.6 fmol and 0.2-1.0 fmol for aglycones (daidzein, glycitein, genistein, formononetin, and biochanin A), respectively. PMID:16138685

  20. Supercritical fluid extraction and ultra performance liquid chromatography of respiratory quinones for microbial community analysis in environmental and biological samples.

    PubMed

    Hanif, Muhammad; Atsuta, Yoichi; Fujie, Koichi; Daimon, Hiroyuki

    2012-01-01

    Microbial community structure plays a significant role in environmental assessment and animal health management. The development of a superior analytical strategy for the characterization of microbial community structure is an ongoing challenge. In this study, we developed an effective supercritical fluid extraction (SFE) and ultra performance liquid chromatography (UPLC) method for the analysis of bacterial respiratory quinones (RQ) in environmental and biological samples. RQ profile analysis is one of the most widely used culture-independent tools for characterizing microbial community structure. A UPLC equipped with a photo diode array (PDA) detector was successfully applied to the simultaneous determination of ubiquinones (UQ) and menaquinones (MK) without tedious pretreatment. Supercritical carbon dioxide (scCO(2)) extraction with the solid-phase cartridge trap proved to be a more effective and rapid method for extracting respiratory quinones, compared to a conventional organic solvent extraction method. This methodology leads to a successful analytical procedure that involves a significant reduction in the complexity and sample preparation time. Application of the optimized methodology to characterize microbial communities based on the RQ profile was demonstrated for a variety of environmental samples (activated sludge, digested sludge, and compost) and biological samples (swine and Japanese quail feces). PMID:22391598

  1. Comparison of ultra-high performance supercritical fluid chromatography and ultra-high performance liquid chromatography for the separation of spirostanol saponins.

    PubMed

    Zhu, Ling-Ling; Zhao, Yang; Xu, Yong-Wei; Sun, Qing-Long; Sun, Xin-Guang; Kang, Li-Ping; Yan, Ren-Yi; Zhang, Jie; Liu, Chao; Ma, Bai-Ping

    2016-02-20

    Spirostanol saponins are important active components of some herb medicines, and their isolation and purification are crucial for the research and development of traditional Chinese medicines. We aimed to compare the separation of spirostanol saponins by ultra-high performance supercritical fluid chromatography (UHPSFC) and ultra-high performance liquid chromatography (UHPLC). Four groups of spirostanol saponins were separated respectively by UHPSFC and UHPLC. After optimization, UHPSFC was performed with a HSS C18 SB column or a Diol column and with methanol as the co-solvent. A BEH C18 column and mobile phase containing water (with 0.1% formic acid) and acetonitrile were used in UHPLC. We found that UHPSFC could be performed automatically and quickly. It is effective in separating the spirostanol saponins which share the same aglycone and vary in sugar chains, and is very sensitive to the number and the position of hydroxyl groups in aglycones. However, the resolution of spirostanol saponins with different aglycones and the same sugar moiety by UHPSFC was not ideal and could be resolved by UHPLC instead. UHPLC is good at differentiating the variation in aglycones, and is influenced by double bonds in aglycones. Therefore, UHPLC and UHPSFC are complementary in separating spirostanol saponins. Considering the naturally produced spirostanol saponins in herb medicines are different both in aglycones and in sugar chains, a better separation can be achieved by combination of UHPLC and UHPSFC. UHPSFC is a powerful technique for improving the resolution when UHPLC cannot resolve a mixture of spirostanol saponins and vice versa. PMID:26707085

  2. Alkaloids analysis using off-line two-dimensional supercritical fluid chromatography × ultra-high performance liquid chromatography.

    PubMed

    Li, Kuiyong; Fu, Qing; Xin, Huaxia; Ke, Yanxiong; Jin, Yu; Liang, Xinmiao

    2014-07-21

    In this study, an off-line two-dimensional (2-D) supercritical fluid chromatography (SFC) × ultra-high performance liquid chromatography (UHPLC) method with high orthogonality was developed for the analysis of the practical amide alkaloids fraction from P. longum L. The effects of SFC parameters such as column type, organic modifier, temperature and back-pressure on separation were systematically evaluated. Different selectivity was observed for different columns (BEH, BEH 2-EP, XAmide and CSH FP). An investigation was then carried out of the orthogonality of different columns and systems following a geometric approach with a set of amide alkaloid samples. The orthogonality between a CSH FP column and a BEH column reached 50.79%, which was much higher than that for the other columns. While the orthogonality between SFC and UHPLC based on an XAmide column and an HSS T3 column reached 69.84%, which was the highest of all the combinations. At last, the practical amide alkaloids fraction was analyzed with an off-line 2-D chromatography SFC × UHPLC system. In total, at least 340 peaks were detected by this method. Rapid separation in these two dimensions and easy post treatment of SFC facilitated this 2-D system for the separation of complex samples. PMID:24828698

  3. Efficient optimization of ultra-high- performance supercritical fluid chromatographic separation of Rosa sericea by response surface methodology.

    PubMed

    Li, Jin-Rong; Li, Min; Xia, Bing; Ding, Li-Sheng; Xu, Hong-Xi; Zhou, Yan

    2013-07-01

    An approach for rapid optimization of ultra-high-performance supercritical fluid chromatographic (UHPSFC) gradient by response surface methodology was developed for fast separation of complex crude extracts of the leaves of Rosa sericea. The optimization was performed with Box-Behnken designs and the multicriteria response variables were described using Derringer's desirability. Based on factorial design experiments, five factors were selected for Box-Behnken designs to optimize the UHPSFC conditions, which led to 46 experiments being performed within 8 h. An evaporative light-scattering detector (ELSD) was used, and quantitative analysis of main components in R. sericea samples was employed to evaluate the statistical significance of the parameters on UHPSFC-ELSD analytes response. The results indicated that the optimized UHPSFC-ELSD method is very sensitive with LODs and LOQs below 1.19 and 4.55 μg/mL, respectively. The overall intra- and interday variations were less than 3.91 and 6.41%, respectively. The recovery of the method ranged from 95.66 to 104.22%, with RSD < 5.91%. This newly developed UHPSFC-ELSD method was demonstrated to be fast and sensitive in analyzing complex herbal extracts of Traditional Chinese Medicines. PMID:23625629

  4. Study of UltraHigh Performance Supercritical Fluid Chromatography to measure free fatty acids with out fatty acid ester preparation.

    PubMed

    Ashraf-Khorassani, M; Isaac, G; Rainville, P; Fountain, K; Taylor, L T

    2015-08-01

    Most lipids are best characterized by their fatty acids which may differ in (a) chain length, (b) degree of unsaturation, (c) configuration and position of the double bonds, and (d) the presence of other functionalities. Thus, a fast, simple, and quantitative analytical technique to determine naturally occurring free fatty acids (FFA) in different samples is very important. Just as for saponified acylglycerols, the determination of FFA's has generally been carried out by high resolution gas chromatography (HRGC). The use of an open tubular capillary column coupled with a flame ionization or mass spectrometric detector provides for both high resolution and quantification of FFA's but only after conversion of all free fatty acids to fatty acid methyl esters (FAME) or pentafluorobenzyl esters. Unfortunately, volatilization of labile ester derivatives of mono- and poly-unsaturated FFA's can cause both thermal degradation and isomerization of the fatty acid during HRGC. The employment of a second generation instrument (here referred to as UltraHigh Performance Supercritical Fluid Chromatograph, UHPSFC) with high precision for modified flow and repeated back pressure adjustment in conjunction with sub-2μm various bonded silica particles (coupled with evaporative light scattering, ELSD, and mass spectrometric, MS, detection) for separation and detection of the following mixtures is described: (a) 31 free fatty acids, (b) isomeric FFA's, and (c) lipophilic materials in two real world fish oil samples. Limits of detection for FFA's via UHPSFC/MS and UHPSFC/ELSD versus detection of FAME's via HRGC/MS are quantitatively compared. PMID:26093119

  5. Application of ultra-high performance supercritical fluid chromatography for the determination of carotenoids in dietary supplements.

    PubMed

    Li, Bing; Zhao, Haiyan; Liu, Jing; Liu, Wei; Fan, Sai; Wu, Guohua; Zhao, Rong

    2015-12-18

    A quick and simple ultra-high performance supercritical fluid chromatography-photodiode array detector method was developed and validated for the simultaneous determination of 9 carotenoids in dietary supplements. The influences of stationary phase, co-solvent, pressure, temperature and flow rate on the separation of carotenoids were evaluated. The separation of the carotenoids was carried out using an Acquity UPC(2) HSS C18 SB column (150mm×3.0mm, 1.8μm) by gradient elution with carbon dioxide and a 1:2 (v:v) methanol/ethanol mixture. The column temperature was set to 35°C and the backpressure was 15.2MPa. Under these conditions, 9 carotenoids and the internal standard, β-apo-8'-carotenal, were successfully separated within 10min. The correlation coefficients (R(2)) of the calibration curves were all above 0.997, the limits of detection for the 9 carotenoids were in the range of 0.33-1.08μg/mL, and the limits of quantification were in the range of 1.09-3.58μg/mL. The mean recoveries were from 93.4% to 109.5% at different spiking levels, and the relative standard deviations were between 0.8% and 6.0%. This method was successfully applied to the determination of 9 carotenoids in commercial dietary supplements. PMID:26620596

  6. Development and validation of ultra-high performance supercritical fluid chromatography method for determination of illegal dyes and comparison to ultra-high performance liquid chromatography method.

    PubMed

    Khalikova, Maria A; Šatínský, Dalibor; Solich, Petr; Nováková, Lucie

    2015-05-18

    A novel simple, fast and efficient ultra-high performance supercritical fluid chromatography (UHPSFC) method was developed and validated for the separation and quantitative determination of eleven illegal dyes in chili-containing spices. The method involved a simple ultrasound-assisted liquid extraction of illegal compounds with tetrahydrofuran. The separation was performed using a supercritical fluid chromatography system and CSH Fluoro-Phenyl stationary phase at 70°C. The mobile phase was carbon dioxide and the mixture of methanol:acetonitrile (1:1, v/v) with 2.5% formic acid as an additive at the flow rate 2.0 mL min(-1). The UV-vis detection was accomplished at 500 nm for seven compounds and at 420 nm for Sudan Orange G, Butter Yellow, Fast Garnet GBC and Methyl Red due to their maximum of absorbance. All eleven compounds were separated in less than 5 min. The method was successfully validated and applied using three commercial samples of chili-containing spices - Chili sauce (Indonesia), Feferony sauce (Slovakia) and Mojo sauce (Spain). The linearity range of proposed method was 0.50-9.09 mg kg(-1) (r ≥ 0.995). The detection limits were determined as signal to noise ratio of 3 and were ranged from 0.15 mg kg(-1) to 0.60 mg kg(-1) (1.80 mg kg(-1) for Fast Garnet) for standard solution and from 0.25 mg kg(-1) to 1.00 mg kg(-1) (2.50 mg kg(-1) for Fast Garnet, 1.50 mg kg(-1) for Sudan Red 7B) for chili-containing samples. The recovery values were in the range of 73.5-107.2% and relative standard deviation ranging from 0.1% to 8.2% for within-day precision and from 0.5% to 8.8% for between-day precision. The method showed potential for being used to monitor forbidden dyes in food constituents. The developed UHPSFC method was compared to the UHPLC-UV method. The orthogonality of Sudan dyes separation by these two methods was demonstrated. Benefits and drawbacks were discussed showing the reliability of both methods for monitoring of studied illegal dyes in real

  7. Exploring the speed-resolution limits of supercritical fluid chromatography at ultra-high pressures.

    PubMed

    Pauw, Ruben De; Shoykhet Choikhet, Konstantin; Desmet, Gert; Broeckhoven, Ken

    2014-12-29

    The limits of supercritical fluid chromatography have been experimentally explored using inlet pressures at the limits of the current commercial instrumentation (400-600 bar), as well as pressures significantly surpassing this (up to 1050 bar). It was found that efficiencies in the range of 200,000 theoretical plates can be achieved for a void time t0 of roughly 6min using superficially porous particles (2.7 and 4.6μm) while remaining within the pressure limits of current commercial instrumentation and columns. If lower efficiencies are sufficient (<100, 000 plates), smaller particles (e.g. 1.8μm) provide the best trade-off between analysis time and efficiency. Apparent efficiencies of 83,000 (k'=2.2) to 76,000 (k'=6.6) plates could be achieved for void times around 1min by pushing the pressure limits up to 1050 bar on a column length of 500mm. As the optimal mobile phase velocity for these small particle columns is even higher, it is required to use narrow-bore columns (2.1mm ID) to remain within the instrument limits of flow rate. The smaller column volume however puts a strain on the separation efficiency due to extra-column band broadening, resulting in losses up to 50% for weakly retained compounds for column lengths below 250mm. It is also illustrated that when using sub-2μm particles, especially for separations where a significant amount of organic modifier is required, the current pressure limits of state-of-the-art instrumentation can sometimes be insufficient. For a gradient running from 4 to 40 v% methanol on a 300mm column at the optimal flow rate the pressure increases from 420 to 810 bar. Operating SFC-columns with a large pressure gradient induces several (undesired) side effects which have been investigated as well. It has been found that, since the viscosity increases strongly with pressure in SFC, the optimal flow rate and the minimal plate height can significantly change when the column length is changed. Whereas e.g. a 3×150mm column (2.7

  8. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, October 1, 1990--December 31, 1990

    SciTech Connect

    Not Available

    1991-08-01

    The program objective is to generate ultra-fine catalyst particles (20 to 400 {Angstrom} in size) and quantify their potential for improving coal dissolution in the solubilization stage of two-stage catalytic-catalytic liquefaction systems. It has been shown that catalyst activity increases significantly with decreasing particle size for particle sizes in the submicron range. Ultra-fine catalyst particle generation will be accomplished using a novel two-step process. First, the severe conditions produced by a supercritical fluid (e.g., supercritical H{sub 2}O or CO{sub 2}) will be used to dissolve suitable catalyst compounds (e.g., Fe{sub 2}O{sub 3}, FeS{sub 2}, and/or Fe(CO){sub 5}). Sulfur containing compounds may be added to the supercritical solvent during catalyst dissolution to enhance the catalytic activity of the resulting ultra-fine, iron based, catalyst particles.

  9. A fast and sensitive method for the separation of carotenoids using ultra-high performance supercritical fluid chromatography-mass spectrometry.

    PubMed

    Jumaah, Firas; Plaza, Merichel; Abrahamsson, Victor; Turner, Charlotta; Sandahl, Margareta

    2016-08-01

    In this study, a rapid and sensitive ultra-high performance supercritical fluid chromatography-mass spectrometry (UHPSFC-MS) method has been developed and partially validated for the separation of carotenoids within less than 6 min. Six columns of orthogonal selectivity were examined, and the best separation was obtained by using a 1-aminoanthracene (1-AA) column. The length of polyene chain as well as the number of hydroxyl groups in the structure of the studied carotenoids determines their differences in the physiochemical properties and thus the separation that is achieved on this column. All of the investigated carotenoids were baseline separated with resolution values greater than 1.5. The effects of gradient program, back pressure, and column temperature were studied with respect to chromatographic properties such as retention and selectivity. Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) were compared in both positive and negative mode, using both direct infusion and hyphenated with UHPSFC. The ESI in positive mode provided the highest response. The coefficient of determination (R (2)) for all calibration curves were greater than 0.998. Limit of detection (LOD) was in the range of 2.6 and 25.2 ng/mL for α-carotene and astaxanthin, respectively, whereas limit of quantification (LOQ) was in the range of 7.8 and 58.0 ng/mL for α-carotene and astaxanthin, respectively. Repeatability and intermediate precision of the developed UHPSFC-MS method were determined and found to be RSD < 3 % and RSD < 6 %, respectively. The method was applied in order to determine carotenoids in supercritical fluid extracts of microalgae and rosehip. Graphical Abstract Ultra-high performance supercritical fluid chromatography-a rapid separation method for the analysis of carotenoids in rosehip and microalgae samples. PMID:27349917

  10. U.S. program on materials technology for ultra-supercritical coal power plants

    NASA Astrophysics Data System (ADS)

    Viswanathan, R.; Henry, J. F.; Tanzosh, J.; Stanko, G.; Shingledecker, J.; Vitalis, B.; Purgert, R.

    2005-06-01

    The efficiency of conventional fossil power plants is a strong function of the steam temperature and pressure. Research to increase both has been pursued worldwide, since the energy crisis in the 1970s. The need to reduce CO2 emissions has recently provided an additional incentive to increase efficiency. More recently, interest has been evinced in advanced combustion technologies utilizing oxygen instead of air for combustion. The main enabling technology in achieving the above goals is the development of stronger high temperature materials. Extensive research-and-development programs have resulted in numerous high-strength alloys for heavy section piping and for tubing needed to build boilers. The study reported on here is aimed at identifying, evaluating, and qualifying the materials needed for the construction of the critical components of coal-fired boilers that are capable of operating with steam at temperatures of 760 °C (1400 °F) and pressures of 35 MPa (5000 psi). The economic viability of such a plant has been explored. Candidate alloys applicable to various ranges of temperatures have been identified. Stress rupture tests have been completed on the base metal and on welds to a number of alloys. Steamside oxidation tests in an autoclave at 650 °C (1200 °F) and 800 °C (1475 °F) have been completed. Fireside corrosion tests have been conducted under conditions simulating those of waterwalls and superheater/reheater tubes. The weldability and fabricability of the alloys have been investigated. The capabilities of various overlay coatings and diffusion coatings have been examined. This article provides a status report on the progress achieved to date on this project.

  11. Wind tunnel tests of high-lift systems for advanced transports using high-aspect-ratio supercritical wings

    NASA Technical Reports Server (NTRS)

    Allen, J. B.; Oliver, W. R.; Spacht, L. A.

    1982-01-01

    The wind tunnel testing of an advanced technology high lift system for a wide body and a narrow body transport incorporating high aspect ratio supercritical wings is described. This testing has added to the very limited low speed high Reynolds number data base for this class or aircraft. The experimental results include the effects on low speed aerodynamic characteristics of various leading and trailing edge devices, nacelles and pylons, ailerons, and spoilers, and the effects of Mach and Reynolds numbers.

  12. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1992-01-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of solubilization stage of two-stage, catalytic-catalytic liquefaction processes.

  13. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-10-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes.

  14. Ultra Wideband Indoor Positioning Technologies: Analysis and Recent Advances

    PubMed Central

    Alarifi, Abdulrahman; Al-Salman, AbdulMalik; Alsaleh, Mansour; Alnafessah, Ahmad; Al-Hadhrami, Suheer; Al-Ammar, Mai A.; Al-Khalifa, Hend S.

    2016-01-01

    In recent years, indoor positioning has emerged as a critical function in many end-user applications; including military, civilian, disaster relief and peacekeeping missions. In comparison with outdoor environments, sensing location information in indoor environments requires a higher precision and is a more challenging task in part because various objects reflect and disperse signals. Ultra WideBand (UWB) is an emerging technology in the field of indoor positioning that has shown better performance compared to others. In order to set the stage for this work, we provide a survey of the state-of-the-art technologies in indoor positioning, followed by a detailed comparative analysis of UWB positioning technologies. We also provide an analysis of strengths, weaknesses, opportunities, and threats (SWOT) to analyze the present state of UWB positioning technologies. While SWOT is not a quantitative approach, it helps in assessing the real status and in revealing the potential of UWB positioning to effectively address the indoor positioning problem. Unlike previous studies, this paper presents new taxonomies, reviews some major recent advances, and argues for further exploration by the research community of this challenging problem space. PMID:27196906

  15. Ultra Wideband Indoor Positioning Technologies: Analysis and Recent Advances.

    PubMed

    Alarifi, Abdulrahman; Al-Salman, AbdulMalik; Alsaleh, Mansour; Alnafessah, Ahmad; Al-Hadhrami, Suheer; Al-Ammar, Mai A; Al-Khalifa, Hend S

    2016-01-01

    In recent years, indoor positioning has emerged as a critical function in many end-user applications; including military, civilian, disaster relief and peacekeeping missions. In comparison with outdoor environments, sensing location information in indoor environments requires a higher precision and is a more challenging task in part because various objects reflect and disperse signals. Ultra WideBand (UWB) is an emerging technology in the field of indoor positioning that has shown better performance compared to others. In order to set the stage for this work, we provide a survey of the state-of-the-art technologies in indoor positioning, followed by a detailed comparative analysis of UWB positioning technologies. We also provide an analysis of strengths, weaknesses, opportunities, and threats (SWOT) to analyze the present state of UWB positioning technologies. While SWOT is not a quantitative approach, it helps in assessing the real status and in revealing the potential of UWB positioning to effectively address the indoor positioning problem. Unlike previous studies, this paper presents new taxonomies, reviews some major recent advances, and argues for further exploration by the research community of this challenging problem space. PMID:27196906

  16. Ultra-Efficient Engine Technology (UEET), Proof of Concept Compressor, Advanced Compressor Casing T

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Ultra-Efficient Engine Technology (UEET), Proof of Concept Compressor, Advanced Compressor Casing Treatment testing; close up - throttle valve -wide open; oil and air lines plus instrumentation between collector and gearbox.

  17. Advanced Ultra-High Speed Motor for Drilling

    SciTech Connect

    Impact Technologies LLC; University of Texas at Arlington

    2007-03-31

    Three (3) designs have been made for two sizes, 6.91 cm (2.72 inch) and 4.29 cm (1.69 inch) outer diameters, of a patented inverted configured Permanent Magnet Synchronous Machines (PMSM) electric motor specifically for drilling at ultra-high rotational speeds (10,000 rpm) and that can utilize advanced drilling methods. Benefits of these motors are stackable power sections, full control (speed and direction) of downhole motors, flow hydraulics independent of motor operation, application of advanced drilling methods (water jetting and abrasive slurry jetting), and the ability of signal/power electric wires through motor(s). Key features of the final designed motors are: fixed non-rotating shaft with stator coils attached; rotating housing with permanent magnet (PM) rotor attached; bit attached to rotating housing; internal channel(s) in a nonrotating shaft; electric components that are hydrostatically isolated from high internal pressure circulating fluids ('muds') by static metal to metal seals; liquid filled motor with smoothed features for minimized turbulence in the motor during operation; and new inverted coated metal-metal hydrodynamic bearings and seals. PMSM, Induction and Switched Reluctance Machines (SRM), all pulse modulated, were considered, but PMSM were determined to provide the highest power density for the shortest motors. Both radial and axial electric PMSM driven motors were designed with axial designs deemed more rugged for ultra-high speed, drilling applications. The 6.91 cm (2.72 inch) OD axial inverted motor can generate 4.18KW (5.61 Hp) power at 10,000 rpm with a 4 Nm (2.95 ft-lbs) of torque for every 30.48 cm (12 inches) of power section. The 6.91 cm (2.72 inch) OD radial inverted motor can generate 5.03 KW (6.74 Hp) with 4.8 Nm (3.54 ft-lb) torque at 10,000 rpm for every 30.48 cm (12 inches) of power section. The 4.29 cm (1.69 inch) OD radial inverted motor can generate 2.56 KW (3.43 Hp) power with 2.44 Nm (1.8 ft-lb) torque at full speed 10

  18. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, January 1, 1992--March 31, 1992

    SciTech Connect

    Not Available

    1992-05-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period focused on assembling the supercritical particle generation/collection system. Effort was applied to constructing a shakedown testing plan also.

  19. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions

    SciTech Connect

    Not Available

    1991-09-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period was devoted to experimental design and fabrication tasks.

  20. A simple, accurate, time-saving and green method for the determination of 15 sulfonamides and metabolites in serum samples by ultra-high performance supercritical fluid chromatography.

    PubMed

    Zhang, Yuan; Zhou, Wei-E; Li, Shao-Hui; Ren, Zhi-Qin; Li, Wei-Qing; Zhou, Yu; Feng, Xue-Song; Wu, Wen-Jie; Zhang, Feng

    2016-02-01

    An analytical method based on ultra-high performance supercritical fluid chromatography (UHPSFC) with photo-diode array detection (PDA) has been developed to quantify 15 sulfonamides and their N4-acetylation metabolites in serum. Under the optimized gradient elution conditions, it took only 7min to separate all 15 sulfonamides and the critical pairs of each parent drug and metabolite were completely separated. Variables affecting the UHPSFC were optimized to get a better separation. The performance of the developed method was evaluated. The UHPSFC method allowed the baseline separation and determination of 15 sulfonamides and metabolites with limit of detection ranging from 0.15 to 0.35μg/mL. Recoveries between 90.1 and 102.2% were obtained with satisfactory precision since relative standard deviations were always below 3%. The proposed method is simple, accurate, time-saving and green, it is applicable to a variety of sulfonamides detection in serum samples. PMID:26780846

  1. In-situ measurements of the oxidation of AISI 316L(NG) and its constituents (Fe,Cr, Ni) in ultra-supercritical water

    SciTech Connect

    Betova, Iva; Bojinov, Martin; Kinnunen, Petri; Lehtovuori, Viivi; Peltonen, Seppo; Penttila, Sami; Saario, Timo

    2006-07-01

    Several new nuclear reactor designs utilizing supercritical water as coolant are currently being developed. In the European concept the design pressure is 25 MPa and reactor inlet/outlet temperatures 290 deg C/520 deg C. While benefits include better coolant thermal conductivity, increase in efficiency and simpler overall design, many material related questions need to be solved such as oxidation and radiation resistance with simultaneous need to maintain creep strength. This calls for the development of in-situ monitoring methods for the material/environment combination in question. In the present paper, in-situ electrical and electrochemical measurements during oxidation of AISI 316L(NG) and its pure metal constituents (Fe,Cr and Ni) in ultra-supercritical water (500-700 deg C, 30 MPa) have been reproducibly obtained. The oxidation kinetics was followed using the contact electric resistance (CER) and contact electric impedance (CEI) techniques. First attempts have been made to correlate properties of the resulting oxides with the corresponding weight gain data. In addition, impedance spectra of the Ni-Ni contact during oxidation have been reproducibly measured at 500 and 600 deg C. They could be quantitatively interpreted using general considerations of the corrosion process and the Mixed-Conduction Model for oxide films. Preliminary estimates of the diffusion coefficients of principal ionic and electronic current carriers have been obtained and their relevance with respect to available data on Ni oxidation is discussed. (authors)

  2. The analysis of beta-agonists by packed-column supercritical fluid chromatography with ultra-violet and atmospheric pressure chemical ionisation mass spectrometric detection.

    PubMed

    Jones, D C; Dost, K; Davidson, G; George, M W

    1999-06-01

    Packed-column supercritical fluid chromatography (pSFC) using ultra-violet (UV) and atmospheric pressure chemical ionisation (APCI) mass spectrometry (MS) provides a versatile method for the identification and quantification of beta-agonists. We have achieved good separation of clenbuterol, salbutamol, terbutaline and fenoterol with good resolution and reasonable retention times using a high concentration of methanol modifier in the supercritical CO2, together with small amounts of both acidic (trifluoroacetic acid, TFAA) and basic (triethylamine, TEA, or diethylamine, DEA) additives. APCI-MS gave unambiguous identification of the 4 analytes, and increasing cone voltage provided informative fragmentation patterns. The pSFC-MS technique was shown to be linear (R2 > or = 0.996) over the concentration range 1-50 micrograms ml-1. Single ion monitoring (SIM) gave detection limits (on-column) of 2.5 ng (clenbuterol), 0.83 ng (terbutaline), 7.6 ng (salbutamol) and 2.7 ng (fenoterol). The pSFC-MS system was shown to be reproducible within a day, between days, and between restrictors. Analysis of milk samples 'spiked' with beta-agonists showed that the matrix caused no interference, with detection limits of approximately 500 micrograms l-1 of beta-agonists. More dilute solutions could be analysed by pre-concentration before the SFC stage. PMID:10736867

  3. Rapid characterization of commercial polysorbate 80 by ultra-high performance supercritical fluid chromatography combined with quadrupole time-of-flight mass spectrometry.

    PubMed

    Pan, Jinheng; Ji, Yu; Du, Zhenxia; Zhang, Jianwen

    2016-09-23

    Polysorbate 80, as a nonionic surfactant, is widely used in the food, personal care, and pharmaceutical industries due to the advantages of high surface activity, low toxicity, etc. In fact, the products of polysorbate 80 are complex mixtures of oligomers. In this work, a novel and fast method was developed to characterize the commercial polysorbate 80 by ultra-high performance supercritical fluid chromatography (UHPSFC) combined with quadrupole time-of-flight mass spectrometry (QTOF-MS). Some crucial parameters, such as temperature, back pressure and flow rate were optimized. UHPSFC could distinguish n-mer from (n-1)-mer and (n+1)-mer in the same series, which provided the high separation resolution needed for quantitative determination of each oligomer in same series. It was not achieved in previous studies. Furthermore, the characteristic ion fragments were found in MS/MS experiment and used to identify different series. The results revealed that main components of this nonionic surfactant comprise polyethylene oxide (PEO), PEO-monooleate, PEO-isosorbide, PEO-isosorbide monooleate, PEO-isosorbide dioleate, PEO-sorbitan, PEO-sorbitan monooleate, PEO-sorbitan dioleate and PEO-sorbitan trioleate, etc. The separation was performed using BEH stationary phase, so the relationship between molecular structure of these oligomers and chromatographic retention behavior in supercritical fluid chromatography were also investigated for first time. The whole analytical process only takes 8min for one sample. Therefore, UHPSFC-QTOF-MS is a simple, novel and efficient tool to analyze polysorbate 80. PMID:27578407

  4. Analysis of glucuronide and sulfate steroids in urine by ultra-high-performance supercritical-fluid chromatography hyphenated tandem mass spectrometry.

    PubMed

    Doué, Mickael; Dervilly-Pinel, Gaud; Pouponneau, Karinne; Monteau, Fabrice; Le Bizec, Bruno

    2015-06-01

    Profiling conjugated urinary steroids to detect anabolic-steroid misuse is recognized as an efficient analytical strategy in both chemical-food-safety and anti-doping fields. The relevance and robustness of such profiling rely on the analysis of glucuronide and sulfate steroids, which is expected to have properties including accuracy, specificity, sensitivity, and, if possible, rapidity. In this context, the ability of ultra-high-performance supercritical-fluid chromatography (UHPSFC) hyphenated tandem mass spectrometry (MS-MS) to provide reliable and accurate phase II analysis of steroids was assessed. Four stationary phases with sub-2 μm particles (BEH, BEH 2-ethyl-pyridine, HSS C18 SB, and CSH fluorophenyl) were screened for their capacity to separate several conjugated steroid isomers. Analytical conditions including stationary phase, modifier composition and percentage, back pressure, column temperature, and composition and flow rate of make-up solvent were investigated to improve the separation and/or the sensitivity. Thus, an analytical procedure enabling the analysis of eight glucuronide and 12 sulfate steroids by two different methods in 12 and 15 min, respectively, was optimized. The two procedures were evaluated, and UHPSFC-MS-MS analysis revealed its ability to provide sensitive (limits of quantification: 0.1 ng mL(-1) and 0.5 ng mL(-1) for sulfate and glucuronide steroids, respectively) and reliable quantitative performance (R(2) > 0.995, RSD < 20%, and bias < 30%) through the use of suitable labeled internal standards. Comparison with UHPLC-MS-MS was performed, and UHPSFC-MS-MS obtained better performance in terms of sensitivity. Finally, as a proof of concept, this so-called green technology was used in a chemical-food-safety context to profile steroid conjugates in urine samples from bovines treated with estradiol. Graphical Abstract Glucuronide and sulfate steroids analysis in urine by ultra-high performance supercritical fluid

  5. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, January 1, 1991--March 31, 1991

    SciTech Connect

    Not Available

    1991-09-01

    The program objective is to generate ultra-fine catalyst particles (20 to 400 {Angstrom} in size) and quantify their potential for improving coal dissolution in the solubilization stage of two-stage catalytic-catalytic liquefaction systems. In the first quarterly report for this program the concept behind our approach was detailed, the structure of the program was presented, key technical issues were identified, preliminary designs were outlined, and technical progress was discussed. All progress made during the second quarter of this program related to experiment design of the proposed supercritical expansion technique for generating ultra-fine, iron compound, catalyst particles. This second quarterly report, therefore, presents descriptions of the final designs for most system components; diagnostic approaches and designs for determining particles size and size distributions, and the composition of the pre-expansion supercritical solution; and the overall technique progress made during this reporting period. 6 refs., 15 figs., 1 tab.

  6. High Pressure Steam Oxidation of Alloys for Advanced Ultra-Supercritical Conditions

    SciTech Connect

    Holcomb, Gordon R.

    2014-08-05

    A steam oxidation test was conducted at 267 ± 17 bar and 670°C for 293 hr. A comparison test was run at 1 bar. All of the alloys showed an increase in scale thickness and oxidation rate with pressure, and TP304H and IN625 had very large increases. Fine-grained TP304H at 267 bar behaved like a coarse grained alloy, indicative of high pressure increasing the critical Cr level needed to form and maintain a chromia scale. At 267 bar H230, H263, H282, IN617 and IN740 had kp values a factor of one–to-two orders of magnitude higher than at 1 bar. IN625 had a four order of magnitude increase in kp at 267 bar compared to 1 bar. Possible causes for increased oxidation rates with increased pressure were examined, including increased solid state diffusion within the oxide scale and increased critical Cr content to establish and maintain a chromia scale.

  7. Supercritical fluid-mediated methods to encapsulate drugs: recent advances and new opportunities.

    PubMed

    Naylor, Andrew; Lewis, Andrew L; Ilium, Lisbeth

    2011-12-01

    With the advent of the development of novel pharmaceutical products and therapies, there is a need for effective delivery of these products to patients. Dependent on whether they are small-molecular weight drugs or biologics, many new compounds may suffer from poor solubility, poor stability or require frequent administration and therefore require optimized delivery. For example, the utilization of polymorphism and the enhanced solubility in the amorphous state is being exploited to improve the dissolution of small-molecular weight poorly soluble drugs. This can be achieved by the formation of solid dispersions in water-soluble matrices. In addition, encapsulation in biodegradable polymeric materials is one potential route to reduce the frequency of administration through the formation of sustained-release formulations. This is desirable for biologics, for example, which generally require administration once or twice daily. Supercritical fluid processing can achieve both of these outcomes, and this review focuses on the use of supercritical CO2 to encapsulate active pharmaceutical ingredients to enhance solubility or achieve sustained release. Using supercritical CO2-mediated processes provides a clean and potentially solvent-free route to prepare novel drug products and is therefore an attractive alternative to conventional manufacturing technologies. PMID:22833981

  8. Simultaneous determination of 17 disperse dyes in textile by ultra-high performance supercritical fluid chromatography combined with tandem mass spectrometry.

    PubMed

    Zhou, Ying; Du, Zhenxia; Zhang, Yun

    2014-09-01

    A simple, highly sensitive and fast procedure for the control of 17 allergenic and prohibited disperse dyes in textile products was optimized. The method was based on ultrasound assisted extraction of textile samples with 10 mL of methanol under controlled conditions (30 min, 70°C). The extracts were analyzed by the ultra-high performance supercritical fluid chromatography (UHPSFC) system coupled with triple quadrupole tandem mass spectrometry (MS/MS). Four stationary phases (BEH, BEH 2-ethyl-pyridine, HSS C18 SB and CSH fluorophenyl) were screened as well as analytical conditions (modifier percentage, backpressure and column temperature) were investigated to improve the separation. All 17 disperse dyes were simultaneously separated and determined by UHPSFC-MS/MS in 5 min. The dyes were monitored via the ESI(+) ionization method and quantified by 3-channel multiple reaction monitoring (MRM). The calibrations were performed and good linear relationship (R≥0.99) was observed within the concentration range of 2-50 μg mL(-1). Satisfactory recoveries (70.55-103.03%) of all the disperse dyes spiked with standards at different levels were demonstrated. This is the first report on the simultaneous analysis of disperse dyes using UHPSFC-MS/MS. PMID:24913864

  9. Advanced Computational Thermal Fluid Physics (CTFP) and Its Assessment for Light Water Reactors and Supercritical Reactors

    SciTech Connect

    D.M. McEligot; K. G. Condie; G. E. McCreery; H. M. McIlroy; R. J. Pink; L.E. Hochreiter; J.D. Jackson; R.H. Pletcher; B.L. Smith; P. Vukoslavcevic; J.M. Wallace; J.Y. Yoo; J.S. Lee; S.T. Ro; S.O. Park

    2005-10-01

    Background: The ultimate goal of the study is the improvement of predictive methods for safety analyses and design of Generation IV reactor systems such as supercritical water reactors (SCWR) for higher efficiency, improved performance and operation, design simplification, enhanced safety and reduced waste and cost. The objective of this Korean / US / laboratory / university collaboration of coupled fundamental computational and experimental studies is to develop the supporting knowledge needed for improved predictive techniques for use in the technology development of Generation IV reactor concepts and their passive safety systems. The present study emphasizes SCWR concepts in the Generation IV program.

  10. Electrochemistry in supercritical fluids.

    PubMed

    Branch, Jack A; Bartlett, Philip N

    2015-12-28

    A wide range of supercritical fluids (SCFs) have been studied as solvents for electrochemistry with carbon dioxide and hydrofluorocarbons (HFCs) being the most extensively studied. Recent advances have shown that it is possible to get well-resolved voltammetry in SCFs by suitable choice of the conditions and the electrolyte. In this review, we discuss the voltammetry obtained in these systems, studies of the double-layer capacitance, work on the electrodeposition of metals into high aspect ratio nanopores and the use of metallocenes as redox probes and standards in both supercritical carbon dioxide-acetonitrile and supercritical HFCs. PMID:26574527

  11. Electrochemistry in supercritical fluids

    PubMed Central

    Branch, Jack A.; Bartlett, Philip N.

    2015-01-01

    A wide range of supercritical fluids (SCFs) have been studied as solvents for electrochemistry with carbon dioxide and hydrofluorocarbons (HFCs) being the most extensively studied. Recent advances have shown that it is possible to get well-resolved voltammetry in SCFs by suitable choice of the conditions and the electrolyte. In this review, we discuss the voltammetry obtained in these systems, studies of the double-layer capacitance, work on the electrodeposition of metals into high aspect ratio nanopores and the use of metallocenes as redox probes and standards in both supercritical carbon dioxide–acetonitrile and supercritical HFCs. PMID:26574527

  12. Design philosophy of long range LFC transports with advanced supercritical LFC airfoils. [laminar flow control

    NASA Technical Reports Server (NTRS)

    Pfenninger, Werner; Vemuru, Chandra S.

    1988-01-01

    The achievement of 70 percent laminar flow using modest boundary layer suction on the wings, empennage, nacelles, and struts of long-range LFC transports, combined with larger wing spans and lower span loadings, could make possible an unrefuelled range halfway around the world up to near sonic cruise speeds with large payloads. It is shown that supercritical LFC airfoils with undercut front and rear lower surfaces, an upper surface static pressure coefficient distribution with an extensive low supersonic flat rooftop, a far upstream supersonic pressure minimum, and a steep subsonic rear pressure rise with suction or a slotted cruise flap could alleviate sweep-induced crossflow and attachment-line boundary-layer instability. Wing-mounted superfans can reduce fuel consumption and engine tone noise.

  13. Assessment of ultra high performance supercritical fluid chromatography as a separation technique for the analysis of seized drugs: Applicability to synthetic cannabinoids.

    PubMed

    Breitenbach, Stephanie; Rowe, Walter F; McCord, Bruce; Lurie, Ira S

    2016-04-01

    The recent development of modern methods for ultra high performance supercritical fluid chromatography (UHPSFC) has great potential for impacting the analysis of seized drugs. In the separation of synthetic cannabinoids the technique has the potential to produce superior resolution of positional isomers and diastereomers. To demonstrate this potential we have examined the capability of UHPSFC for the analysis of two different groups of synthetic cannabinoids. The first group was a mixture of 22 controlled synthetic cannabinoids, and the second group included JWH018 and nine of its non-controlled positional isomers The clear superiority of UHPSFC over other separation techniques was demonstrated, in that it was capable of near baseline separation of all 10 positional isomers using a chiral column. In total we examined four achiral columns, including Acquity UPC(2) Torus 2-PIC, Acquity UPC(2) Torus Diol, Acquity UPC(2) Torus DEA and Acquity UPC(2) Torus 1-AA (1.7μm 3.0×100mm), and three chiral columns, including Acquity UPC(2) Trefoil AMY1, Acquity UPC(2) Trefoil CEL1 and Acquity UPC(2) Trefoil CEL2 (2.5μm 3.0×150mm), using mobile phase compositions that combined carbon dioxide with methanol, acetonitrile, ethanol or isopropanol modifier gradients. Detection was performed using simultaneous PDA UV detection and quadrupole mass spectrometry. The orthogonality of UHPSFC, GC and UHPLC for the analysis of these compounds was demonstrated using principal component analysis. Overall we feel that this new technique should prove useful in the analysis and detection of seized drug samples, and will be a useful addition to the compendium of methods for drug analysis. PMID:26947165

  14. Ultra-high performance supercritical fluid chromatography coupled with quadrupole-time-of-flight mass spectrometry as a performing tool for bioactive analysis.

    PubMed

    Grand-Guillaume Perrenoud, Alexandre; Guillarme, Davy; Boccard, Julien; Veuthey, Jean-Luc; Barron, Denis; Moco, Sofia

    2016-06-10

    Secondary metabolites are an almost unlimited reservoir of potential bioactive compounds. In view of the wide chemical space covered by natural compounds, their comprehensive analysis requires multiple cutting-edge approaches. This study evaluates the applicability of ultra-high performance supercritical fluid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPSFC-QqToF-MS) as an analytical strategy for plant metabolites profiling. Versatility of this analytical platform was first assessed using 120 highly diverse natural compounds (according to lipophilicity, hydrogen bond capability, acid-base properties, molecular mass and chemical structure) that were screened on a set of 15 rationally chosen stationary phase chemistries. UHPSFC-QqToF-MS provides a suitable analytical solution for 88% of the tested compounds. Three stationary phases (Diol, not endcapped C18 and 2-EP) were highlighted as particularly polyvalent, since they allow suitable elution of 101 out of 120 natural compounds. The systematic evaluation of retention and selectivity of natural compounds further underlined the suitability of these three columns for the separation of natural compounds. This reduced set of key stationary phases constitutes a basis for untargeted scouting analysis and method development. Even if they were less versatile, stationary phases such as endcapped T3C18, polar P-PFP, were nevertheless found to provide extended selectivity for specific natural molecules sub-classes. Finally, the identified polyvalent conditions were successfully applied for the analysis of complex polar and non-polar plant extracts. These first experimental hits demonstrate the full applicability and potential of UHPSFC-QqToF-MS for plant metabolite profiling. PMID:27156735

  15. Development of advanced off-design models for supercritical carbon dioxide power cycles

    SciTech Connect

    Dyreby, J. J.; Klein, S. A.; Nellis, G. F.; Reindl, D. T.

    2012-07-01

    In the search for increased efficiency of utility-scale electricity generation, Brayton cycles operating with supercritical carbon dioxide (S-CO{sub 2}) have found considerable interest. There are two main advantages of a S-CO{sub 2} Brayton cycle compared to a Rankine cycle: 1) equal or greater thermal efficiencies can be realized using significantly smaller turbomachinery, and 2) heat rejection is not limited by the saturation temperature of the working fluid, which has the potential to reduce or completely eliminate the need for cooling water and instead allow dry cooling. While dry cooling is especially advantageous for power generation in arid climates, a reduction of water consumption in any location will be increasingly beneficial as tighter environmental regulations are enacted in the future. Because daily and seasonal weather variations may result in a plant operating away from its design point, models that are capable of predicting the off-design performance of S-CO{sub 2} power cycles are necessary for characterizing and evaluating cycle configurations and turbomachinery designs on an annual basis. To this end, an off-design model of a recuperated Brayton cycle was developed based on the radial turbomachinery currently being investigated by Sandia National Laboratory. (authors)

  16. Oxidation of advanced steam turbine alloys

    SciTech Connect

    Holcomb, G.R.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.

    2006-03-01

    Advanced or ultra supercritical (USC) steam power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  17. Subsonic Ultra Green Aircraft Research Phase II: N+4 Advanced Concept Development

    NASA Technical Reports Server (NTRS)

    Bradley, Marty K.; Droney, Christopher K.

    2012-01-01

    This final report documents the work of the Boeing Subsonic Ultra Green Aircraft Research (SUGAR) team on Task 1 of the Phase II effort. The team consisted of Boeing Research and Technology, Boeing Commercial Airplanes, General Electric, and Georgia Tech. Using a quantitative workshop process, the following technologies, appropriate to aircraft operational in the N+4 2040 timeframe, were identified: Liquefied Natural Gas (LNG), Hydrogen, fuel cell hybrids, battery electric hybrids, Low Energy Nuclear (LENR), boundary layer ingestion propulsion (BLI), unducted fans and advanced propellers, and combinations. Technology development plans were developed.

  18. Advanced Use of Therma-Probe for Ultra-Shallow Junction Monitoring

    NASA Astrophysics Data System (ADS)

    Bogdanowicz, Janusz; Clarysse, Trudo; Smets, Gerrit; Rosseel, Erik; Vandervorst, Wilfried

    2011-11-01

    Therma-Probe® (TP) is widely used in the semiconductor industry for the Statistical Process Control (SPC) monitoring of the various ion implantation steps included in the Complementary Metal Oxide Semiconductor process. This fully optical, hence non-destructive and fast, pump-probe technique measures the probe laser reflectance (DC reflectance) as well as the pump-laser-induced changes in probe reflectance (AC reflectance, also called TW signal). In this paper, we report on the latest advances in the use of TP for the monitoring of ultra-shallow junctions both before and after annealing of the implanted layers.

  19. "Ultra"-Fast Fracture Strength of Advanced Structural Ceramic Materials Studied at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Choi, Sung R.; Gyekenyesi, John P.

    1999-01-01

    The accurate determination of inert strength is important in reliable life prediction of structural ceramic components. At ambient temperature, the inert strength of a brittle material is typically regarded as free of the effects of slow crack growth due to stress corrosion. Therefore, the inert strength can be determined either by eliminating active species, especially moisture, with an appropriate inert medium, or by using a very high test rate. However, at elevated temperatures, the concept or definition of the inert strength of brittle ceramic materials is not clear, since temperature itself is a degrading environment, resulting in strength degradation through slow crack growth and/or creep. Since the mechanism to control strength is rate-dependent viscous flow, the only conceivable way to determine the inert strength at elevated temperatures is to utilize a very fast test rate that either minimizes the time for or eliminates slow crack growth. Few experimental studies have measured the elevated-temperature, inert (or "ultra"-fast fracture) strength of advanced ceramics. At the NASA Lewis Research Center, an experimental study was initiated to better understand the "ultra"-fast fracture strength behavior of advanced ceramics at elevated temperatures. Fourteen advanced ceramics - one alumina, eleven silicon nitrides, and two silicon carbides - have been tested using constant stress-rate (dynamic fatigue) testing in flexure with a series of stress rates including the "ultra"-fast stress rate of 33 000 MPa/sec with digitally controlled test frames. The results for these 14 advanced ceramics indicate that, notwithstanding possible changes in flaw populations as well as flaw configurations because of elevated temperatures, the strength at 33 000 MPa/sec approached the room-temperature strength or reached a higher value than that determined at the conventional test rate of 30 MPa/sec. On the basis of the experimental data, it can be stated that the elevated

  20. BESTIA - The next generation ultra-fast CO2 laser for advanced accelerator research

    NASA Astrophysics Data System (ADS)

    Pogorelsky, Igor V.; Babzien, Markus; Ben-Zvi, Ilan; Skaritka, John; Polyanskiy, Mikhail N.

    2016-09-01

    Over the last two decades, BNL's ATF has pioneered the use of high-peak power CO2 lasers for research in advanced accelerators and radiation sources. Our recent developments in ion acceleration, Compton scattering, and IFELs have further underscored the benefits from expanding the landscape of strong-field laser interactions deeper into the mid-infrared (MIR) range of wavelengths. This extension validates our ongoing efforts in advancing CO2 laser technology, which we report here. Our next-generation, multi-terawatt, femtosecond CO2 laser will open new opportunities for studying ultra-relativistic laser interactions with plasma in the MIR spectral domain, including new regimes in the particle acceleration of ions and electrons.

  1. BESTIA - the next generation ultra-fast CO2 laser for advanced accelerator research

    DOE PAGESBeta

    Pogorelsky, Igor V.; Babzien, Markus; Ben-Zvi, Ilan; Skaritka, John; Polyanskiy, Mikhail N.

    2015-12-02

    Over the last two decades, BNL’s ATF has pioneered the use of high-peak power CO2 lasers for research in advanced accelerators and radiation sources. In addition, our recent developments in ion acceleration, Compton scattering, and IFELs have further underscored the benefits from expanding the landscape of strong-field laser interactions deeper into the mid-infrared (MIR) range of wavelengths. This extension validates our ongoing efforts in advancing CO2 laser technology, which we report here. Our next-generation, multi-terawatt, femtosecond CO2 laser will open new opportunities for studying ultra-relativistic laser interactions with plasma in the MIR spectral domain, including new regimes in the particlemore » acceleration of ions and electrons.« less

  2. Elevated-Temperature "Ultra" Fast Fracture Strength of Advanced Ceramics: An Approach to Elevated-Temperature "Inert" Strength

    NASA Technical Reports Server (NTRS)

    Choi, S. R.; Gyekenyesi, J. P.

    1999-01-01

    The determination of "ultra" fast fracture strengths of five silicon nitride ceramics at elevated temperatures has been made by using constant stress-rate ("dynamic fatigue") testing with a series of "ultra" fast test rates. The test material included four monolithic and one SiC whisker-reinforced composite silicon nitrides. Of the five test materials, four silicon nitrides exhibited the elevated -temperature strengths that approaches their respective room-temperature strengths at an "ultra" fast test rate of 3.3 x 10(exp 4) MPa/s. This implies that slow cracks growth responsible for elevated-temperature failure can be eliminated or minimized by using the "ultra" fast test rate. These ongoing experimental results have shed light on laying a theoretical and practical foundation on the concept and definition of elevated-temperature "inert" strength behavior of advanced ceramics.

  3. Supercritical Fluid Facilitated Growth of Copper and Aluminum Oxide Nanoparticles

    ERIC Educational Resources Information Center

    Williams, Geoffrey L.; Vohs, Jason K.; Brege, Jonathan J.; Fahlman, Bradley D.

    2005-01-01

    Supercritical fluids (SCFs) possess properties that are intermediate between liquids and gases. The combination of supercritical fluid technology with advanced characterization techniques such as electron microscopy provided a practical and rewarding undergraduate laboratory experiment.

  4. Oxidation of alloys for advanced steam turbines

    SciTech Connect

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Bullard, Sophie J.; Ziomek-Moroz, M.; Alman, David E.

    2005-01-01

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of advanced alloys for use in USC systems, with emphasis placed on alloys for high- and intermediate-pressure turbine sections.

  5. Worldwide supercritical power plants: Status and future

    SciTech Connect

    Gorokhov, V.A.; Ramezan, M.; Ruth, L.A.; Kim, S.S.

    1999-07-01

    During the last decade leading industrial countries initiated a new wave of research and development on supercritical (SC) steam power plants. This new interest is accompanied by the jump from SC steam parameters to ultra-supercritical (USC) parameters and was initiated mostly due to the increase in cost of fuel on the world market, and by increased environmental regulations including reduction of greenhouse gases. As a result, a significant number of new pulverized coal (PC) power units with increased efficiency and reduced emissions were installed in the last two decades, and a few more are planned to be installed in the near future. Different driving forces are responsible for development and implementation of highly efficient advanced PC-fired systems: need for new capacity, quality and cost of fuel, level of technology development, environmental requirements, and internal situation with regard to power supply (deregulation). For example, in Europe, Germany in particular, controlling CO{sub 2} is a major issue in any new installation, while in Japan economics is the major issue as the costs of imported fuels are high, and there are greater economic incentives for efficiency improvement. This paper discusses the status of existing and planned SC and USC power plants worldwide and their technical and environmental performance.

  6. Advanced Fuels Reactor using Aneutronic Rodless Ultra Low Aspect Ratio Tokamak Hydrogenic Plasmas

    NASA Astrophysics Data System (ADS)

    Ribeiro, Celso

    2015-11-01

    The use of advanced fuels for fusion reactor is conventionally envisaged for field reversed configuration (FRC) devices. It is proposed here a preliminary study about the use of these fuels but on an aneutronic Rodless Ultra Low Aspect Ratio (RULART) hydrogenic plasmas. The idea is to inject micro-size boron pellets vertically at the inboard side (HFS, where TF is very high and the tokamak electron temperature is relatively low because of profile), synchronised with a proton NBI pointed to this region. Therefore, p-B reactions should occur and alpha particles produced. These pellets will act as an edge-like disturbance only (cp. killer pellet, although the vertical HFS should make this less critical, since the unablated part should appear in the bottom of the device). The boron cloud will appear at midplance, possibly as a MARFE-look like. Scaling of the p-B reactions by varying the NBI energy should be compared with the predictions of nuclear physics. This could be an alternative to the FRC approach, without the difficulties of the optimization of the FRC low confinement time. Instead, a robust good tokamak confinement with high local HFS TF (enhanced due to the ultra low aspect ratio and low pitch angle) is used. The plasma central post makes the RULART concept attractive because of the proximity of NBI path and also because a fraction of born alphas will cross the plasma post and dragged into it in the direction of the central plasma post current, escaping vertically into a hole in the bias plate and reaching the direct electricity converter, such as in the FRC concept.

  7. Constant and sliding-pressure options for new supercritical plants

    SciTech Connect

    Vitalis, B.P.

    2006-01-15

    Sliding-pressure, supercritical plants are all the rage. They generally include certain design features developed for markets and operating environments outside the US, where new coal-fired plants have been built in recent decades. US market conditions are different, and considerable capital cost savings with negligible operating cost differences are possible if technology options are considered for the next wave of supercritical and ultra-supercritical steam plants. 8 figs.

  8. A hybrid approach for generating ultra-short bunches for advanced accelerator applications

    SciTech Connect

    Stratakis, Diktys

    2015-09-01

    Generation of electron beams with high phase-space density, short bunch length and high peak current is an essential requirement for future linear colliders and bright electron beam sources. Unfortunately, such bunches cannot be produced directly from the source since forces from the mutual repulsion of electrons would destroy the brilliance of the beam within a short distance. Here, we detail a beam dynamics study of an innovative two-stage compression scheme that can generate ultra-short bunches without degrading the beam quality. In the first stage, the beam is compressed with an advanced velocity bunching technique in which the longitudinal phase space is rotated so that electrons on the bunch tail become faster than electrons in the bunch head. In the second stage, the beam is further compressed with a conventional magnetic chicane. With the aid of numerical simulations we show that our two-staged scheme is capable to increase the current of a 50 pC bunch to a notable factor of 100 while the emittance growth can be suppressed to 1% with appropriate tailoring of the initial beam distribution.

  9. Recent Advances and New Techniques in Visualization of Ultra-short Relativistic Electron Bunches

    SciTech Connect

    Xiang, Dao; /SLAC

    2012-06-05

    Ultrashort electron bunches with rms length of {approx} 1 femtosecond (fs) can be used to generate ultrashort x-ray pulses in FELs that may open up many new regimes in ultrafast sciences. It is also envisioned that ultrashort electron bunches may excite {approx}TeV/m wake fields for plasma wake field acceleration and high field physics studies. Recent success of using 20 pC electron beam to drive an x-ray FEL at LCLS has stimulated world-wide interests in using low charge beam (1 {approx} 20 pC) to generate ultrashort x-ray pulses (0.1 fs {approx} 10 fs) in FELs. Accurate measurement of the length (preferably the temporal profile) of the ultrashort electron bunch is essential for understanding the physics associated with the bunch compression and transportation. However, the shorter and shorter electron bunch greatly challenges the present beam diagnostic methods. In this paper we review the recent advances in the measurement of ultra-short electron bunches. We will focus on several techniques and their variants that provide the state-of-the-art temporal resolution. Methods to further improve the resolution of these techniques and the promise to break the 1 fs time barrier is discussed. We review recent advances in the measurement of ultrashort relativistic electron bunches. We will focus on several techniques and their variants that are capable of breaking the femtosecond time barrier in measurements of ultrashort bunches. Techniques for measuring beam longitudinal phase space as well as the x-ray pulse shape in an x-ray FEL are also discussed.

  10. Oxidation of Alloys for Advanced Steam Turbines

    SciTech Connect

    Holcomb, G.R.; Ziomek-Moroz, M.E.; Alman, D.E.

    2006-09-01

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include power generation from coal at 60% efficiency, which requires steam temperatures of up to 760°C. This research examines the steam oxidation of alloys for use in USC systems, with emphasis placed on applications in high- and intermediate-pressure turbines.

  11. Advanced Production Surface Preparation Technology Development for Ultra-High Pressure Diesel Injection

    SciTech Connect

    Grant, Marion B.

    2012-04-30

    In 2007, An Ultra High Injection Pressure (UHIP) fueling method has been demonstrated by Caterpillar Fuel Systems - Product Development, demonstrating ability to deliver U.S. Environment Protection Agency (EPA) Tier 4 Final diesel engine emission performance with greatly reduced emissions handling components on the engine, such as without NOx reduction after-treatment and with only a through-flow 50% effective diesel particulate trap (DPT). They have shown this capability using multiple multi-cylinder engine tests of an Ultra High Pressure Common Rail (UHPCR) fuel system with higher than traditional levels of CEGR and an advanced injector nozzle design. The system delivered better atomization of the fuel, for more complete burn, to greatly reduce diesel particulates, while CEGR or high efficiency NOx reduction after-treatment handles the NOx. With the reduced back pressure of a traditional DPT, and with the more complete fuel burn, the system reduced levels of fuel consumption by 2.4% for similar delivery of torque and horsepower over the best Tier 4 Interim levels of fuel consumption in the diesel power industry. The challenge is to manufacture the components in high-volume production that can withstand the required higher pressure injection. Production processes must be developed to increase the toughness of the injector steel to withstand the UHIP pulsations and generate near perfect form and finish in the sub-millimeter size geometries within the injector. This project resulted in two developments in 2011. The first development was a process and a machine specification by which a high target of compressive residual stress (CRS) can be consistently imparted to key surfaces of the fuel system to increase the toughness of the steel, and a demonstration of the feasibility of further refinement of the process for use in volume production. The second development was the demonstration of the feasibility of a process for imparting near perfect, durable geometry to

  12. Dynamic transition in supercritical iron.

    PubMed

    Fomin, Yu D; Ryzhov, V N; Tsiok, E N; Brazhkin, V V; Trachenko, K

    2014-01-01

    Recent advance in understanding the supercritical state posits the existence of a new line above the critical point separating two physically distinct states of matter: rigid liquid and non-rigid gas-like fluid. The location of this line, the Frenkel line, remains unknown for important real systems. Here, we map the Frenkel line on the phase diagram of supercritical iron using molecular dynamics simulations. On the basis of our data, we propose a general recipe to locate the Frenkel line for any system, the recipe that importantly does not involve system-specific detailed calculations and relies on the knowledge of the melting line only. We further discuss the relationship between the Frenkel line and the metal-insulator transition in supercritical liquid metals. Our results enable predicting the state of supercritical iron in several conditions of interest. In particular, we predict that liquid iron in the Jupiter core is in the "rigid liquid" state and is highly conducting. We finally analyse the evolution of iron conductivity in the core of smaller planets such as Earth and Venus as well as exoplanets: as planets cool off, the supercritical core undergoes the transition to the rigid-liquid conducting state at the Frenkel line. PMID:25424664

  13. Dynamic transition in supercritical iron

    PubMed Central

    Fomin, Yu. D.; Ryzhov, V. N.; Tsiok, E. N.; Brazhkin, V. V.; Trachenko, K.

    2014-01-01

    Recent advance in understanding the supercritical state posits the existence of a new line above the critical point separating two physically distinct states of matter: rigid liquid and non-rigid gas-like fluid. The location of this line, the Frenkel line, remains unknown for important real systems. Here, we map the Frenkel line on the phase diagram of supercritical iron using molecular dynamics simulations. On the basis of our data, we propose a general recipe to locate the Frenkel line for any system, the recipe that importantly does not involve system-specific detailed calculations and relies on the knowledge of the melting line only. We further discuss the relationship between the Frenkel line and the metal-insulator transition in supercritical liquid metals. Our results enable predicting the state of supercritical iron in several conditions of interest. In particular, we predict that liquid iron in the Jupiter core is in the “rigid liquid” state and is highly conducting. We finally analyse the evolution of iron conductivity in the core of smaller planets such as Earth and Venus as well as exoplanets: as planets cool off, the supercritical core undergoes the transition to the rigid-liquid conducting state at the Frenkel line. PMID:25424664

  14. A rapid method for the separation of vitamin D and its metabolites by ultra-high performance supercritical fluid chromatography-mass spectrometry.

    PubMed

    Jumaah, Firas; Larsson, Sara; Essén, Sofia; Cunico, Larissa P; Holm, Cecilia; Turner, Charlotta; Sandahl, Margareta

    2016-04-01

    In this study, a new supercritical fluid chromatography-mass spectrometry (SFC-MS) method has been developed for the separation of nine vitamin D metabolites within less than eight minutes. This is the first study of analysis of vitamin D and its metabolites carried out by SFC-MS. Six columns of orthogonal selectivity were examined, and the best separation was obtained by using a 1-aminoanthracene (1-AA) column. The number and the position of hydroxyl groups in the structure of the studied compounds as well as the number of unsaturated bonds determine the physiochemical properties and, thus the separation of vitamin D metabolites that is achieved on this column. All D2 and the D3 forms were baseline separated with resolution values>1.5. The effects of pressure, temperature, flow rate and different gradient modes were studied. Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) were compared in positive mode, both by direct infusion and after SFC separation. The results showed that the sensitivity in APCI(+) was higher than in ESI(+) using direct infusion. In contrast, the sensitivity in APCI(+) was 6-fold lower than in ESI(+) after SFC separation. The SFC-MS method was validated between 10 and 500ng/mL for all analytes with coefficient of determination (R(2))≥0.999 for all calibration curves. The limits of detection (LOD) were found to range between 0.39 and 5.98ng/mL for 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) and 1-hydroxyvitamin D2 (1OHD2), respectively. To show its potential, the method was applied to human plasma samples from healthy individuals. Vitamin D3 (D3), 25-hydroxyvitamin D3 (25OHD3) and 24,25(OH)2D3 were determined in plasma samples and the concentrations were 6.6±3.0ng/mL, 23.8±9.2ng/mL and 5.4±2.7ng/mL, respectively. PMID:26931428

  15. Development and optimization of ultra-high performance supercritical fluid chromatography mass spectrometry method for high-throughput determination of tocopherols and tocotrienols in human serum.

    PubMed

    Pilařová, Veronika; Gottvald, Tomáš; Svoboda, Pavel; Novák, Ondřej; Benešová, Karolína; Běláková, Sylvie; Nováková, Lucie

    2016-08-31

    The goal of this study was to develop an effective supercritical fluid chromatography method using single quadrupole MS for analysis of all isomeric forms of vitamin E. Finally, two fast and effective methods, the high resolution one and the high speed one, for the determination of 8 vitamin E isomers in human serum were developed. Rapid high-throughput liquid-liquid extraction was selected as a sample preparation step. Sample pretreatment of 100 μL human serum was consisted of protein precipitation with 200 μL ethanol and liquid-liquid extraction by 400 μL hexane/dichloromethane (80/20, v/v). The separation was performed on BEH 2-EP (3.0 × 100 mm, 1.7 μm) stationary phase, using isocratic elution with carbon dioxide and 10 mM ammonium formate in methanol in the ratio 98:2 for high resolution method with run time 4.5 min and in the ratio 95:5 for high speed method, where the run time was 2.5 min. The method development included optimization of key parameters: the choice of the suitable stationary phase and the composition of mobile phase, where an influence of various modifiers, their ratio and additives were tested, and optimization of fine tunning parameters including BPR pressure, flow-rate and column temperature. Quantification of all isomeric forms was performed using SIM (single ion monitoring) experiments in ESI positive ion mode. Both high speed and high resolution chromatographic methods were validated in terms of precision, accuracy, range, linearity, LOD, LOQ and matrix effects using the same LLE procedure. The high resolution method provided more sensitive results (LOD: 0.017-0.083 μg mL(-1)) and better linearity (r(2) > 0.9930) than the high speed one (LOD: 0.083-0.25 μg mL(-1), r(2) > 0.9877) at the cost of double time of analysis. PMID:27506367

  16. Recent advances in ultra-high performance liquid chromatography for the analysis of traditional chinese medicine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Traditional Chinese medicines (TCMs) have been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra Performance Liquid Chromatography (UHPLC) is a relatively new technique offering new possibilities in liquid chromatography. This paper reviews recen...

  17. Advanced Power Ultra-Uprates of Existing Plants (APPU) Final Scientific/Technical Report

    SciTech Connect

    Rubiolo, Pablo R.; Conway, Lawarence E.; Oriani, Luca; Lahoda, Edward J.; DeSilva, Greg; Hu, Min H.; Hartz, Josh; Bachrach, Uriel; Smith, Larry; Dudek, Daniel F.; Gary J. Toman; Feng, Dandong; Hejzlar, Pavel; Kazimi, Mujid S.

    2006-03-31

    This project assessed the feasibility of a Power Ultra-Uprate on an existing nuclear plant. The study determined the technical and design limitations of the current components, both inside and outside the containment. Based on the identified plant bottlenecks, the design changes for major pieces of equipment required to meet the Power Ultra-Uprate throughput were determined. Costs for modified pieces of equipment and for change-out and disposal of the replaced equipment were evaluated. These costs were then used to develop capital, fuel and operating and maintenance cost estimates for the Power Ultra-Uprate plant. The cost evaluation indicates that the largest cost components are the replacement of power (during the outage required for the uprate) and the new fuel loading. Based on these results, the study concluded that, for a standard 4-loop plant, the proposed Power Ultra-Uprate is technically feasible. However, the power uprate is likely to be more expensive than the cost (per Kw electric installed) of a new plant when large capacity uprates are considered (>25%). Nevertheless, the concept of the Power Ultra-Uprate may be an attractive option for specific nuclear power plants where a large margin exists in the steam and power conversion system or where medium power increases (~600 MWe) are needed. The results of the study suggest that development efforts on fuel technologies for current nuclear power plants should be oriented towards improving the fuel performance (fretting-wear, corrosion, uranium load, manufacturing, safety) required to achieve higher burnup rather focusing on potential increases in the fuel thermal output.

  18. BESTIA - the next generation ultra-fast CO2 laser for advanced accelerator research

    SciTech Connect

    Pogorelsky, Igor V.; Babzien, Markus; Ben-Zvi, Ilan; Skaritka, John; Polyanskiy, Mikhail N.

    2015-12-02

    Over the last two decades, BNL’s ATF has pioneered the use of high-peak power CO2 lasers for research in advanced accelerators and radiation sources. In addition, our recent developments in ion acceleration, Compton scattering, and IFELs have further underscored the benefits from expanding the landscape of strong-field laser interactions deeper into the mid-infrared (MIR) range of wavelengths. This extension validates our ongoing efforts in advancing CO2 laser technology, which we report here. Our next-generation, multi-terawatt, femtosecond CO2 laser will open new opportunities for studying ultra-relativistic laser interactions with plasma in the MIR spectral domain, including new regimes in the particle acceleration of ions and electrons.

  19. Oxidation of alloys targeted for advanced steam turbines

    SciTech Connect

    Holcomb, G.R.; Covino, B.S., Jr.; Bullard, S.J.; Ziomek-Moroz, M.; Alman, D.E.

    2006-03-12

    Ultra supercritical (USC) power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy’s Advanced Power Systems Initiatives include coal generation at 60% efficiency, which would require steam temperatures of up to 760°C. This research examines the steamside oxidation of alloys for use in USC systems, with emphasis placed on applications in high- and intermediate-pressure turbines.

  20. RECENT ADVANCES IN ULTRA-HIGH PERFORMANCE LIQUID CHROMATOGRAPHY FOR THE ANALYSIS OF TRADITIONAL CHINESE MEDICINE

    PubMed Central

    Huang, Huilian; Liu, Min; Chen, Pei

    2014-01-01

    Traditional Chinese medicine has been widely used for the prevention and treatment of various diseases for thousands of years in China. Ultra-high performance liquid chromatography (UHPLC) is a relatively new technique offering new possibilities. This paper reviews recent developments in UHPLC in the separation and identification, fingerprinting, quantification, and metabolism of traditional Chinese medicine. Recently, the combination of UHPLC with MS has improved the efficiency of the analysis of these materials. PMID:25045170

  1. Threaded molecular wires as building blocks for advanced polymer blends: WPLEDs, ultra-broadband optical amplifiers, multi color lasers

    NASA Astrophysics Data System (ADS)

    Brovelli, Sergio; Mroz, Marta; Sforazzini, Giuseppe; Virgili, Tersilla; Meinardi, Franco; Paleari, Alberto; Anderson, Harry L.; Lanzani, Guglielmo; Cacialli, Franco

    2011-03-01

    The ability to produce semiconducting polymer blends with white emission spectra, large emission cross sections and broad optical gain is critical to their application in white PLEDs, lasers and broadband amplifiers. Cyclodextrin-encapsulation is an effective means of suppressing detrimental intermolecular interactions, and energy transfer (ET) channels in polymer blends, thus enabling fabrication of white-PLEDs. We show that all such properties combine into a high impact photonic application: ultra-broad optical gain and two-color lasing in a binary polyrotaxane blend. We study the ultrafast photophysics of a blend of a conventional and an encapsulated polyfluorene. The morphology is investigated by microRaman imaging, AFM, and fluorescence lifetime microscopy. We ascribe the ultra-broad optical gain (>850 meV), and the simultaneous ASE for both constituents, to the dual effect of reduced polaron formation and suppressed ET. Our results demonstrate that polyrotaxanes could realistically represent the building blocks for advanced polymer blends with highly controlled optical properties, for applications in solid state lightning, lasers and photovoltaic technologies.

  2. Solvation in supercritical water

    SciTech Connect

    Cochran, H.D. ); Cummings, P.T.; Karaborni, S. . Dept. of Chemical Engineering)

    1991-01-01

    The aim of this work is to determine the solvation structure in supercritical water composed with that in ambient water and in simple supercritical solvents. Molecular dynamics studies have been undertaken of systems that model ionic sodium and chloride, atomic argon, and molecular methanol in supercritical aqueous solutions using the simple point charge model of Berendsen for water. Because of the strong interactions between water and ions, ionic solutes are strongly attractive in supercritical water, forming large clusters of water molecules around each ion. Methanol is found to be a weakly-attractive solute in supercritical water. The cluster of excess water molecules surrounding a dissolved ion or polar molecule in supercritical aqueous solutions is comparable to the solvent clusters surrounding attractive solutes in simple supercritical fluids. Likewise, the deficit of water molecules surrounding a dissolved argon atom in supercritical aqueous solutions is comparable to that surrounding repulsive solutes in simple supercritical fluids. The number of hydrogen bonds per water molecule in supercritical water was found to be about one third the number in ambient water. The number of hydrogen bonds per water molecule surrounding a central particle in supercritical water was only mildly affected by the identify of the central particle--atom, molecule, or ion. These results should be helpful in developing a qualitative understanding of important processes that occur in supercritical water. 29 refs., 6 figs.

  3. NASA Glenn's Advanced Subsonic Combustion Rig Supported the Ultra-Efficient Engine Technology Project's Emissions Reduction Test

    NASA Technical Reports Server (NTRS)

    Beltran, Luis R.

    2004-01-01

    The Advanced Subsonic Combustor Rig (ASCR) is NASA Glenn Research Center's unique high-pressure, high-temperature combustor facility supporting the emissions reduction element of the Ultra-Efficient Engine Technology (UEET) Project. The facility can simulate combustor inlet test conditions up to a pressure of 900 psig and a temperature of 1200 F (non-vitiated). ASCR completed three sector tests in fiscal year 2003 for General Electric, Pratt & Whitney, and Rolls-Royce North America. This will provide NASA and U.S. engine manufacturers the information necessary to develop future low-emission combustors and will help them to better understand durability and operability at these high pressures and temperatures.

  4. Supercritical fluid technology

    SciTech Connect

    Penninger, J.M.L.; McHugh, M.A.; Radosz, M.; Krukonis, V.J.

    1985-01-01

    This book presents the state-of-the-art in the science and technology of supercritical fluid (scf) processing. Current research as described in the book, focuses on developments in equations of state for binary and multicomponent mixtures (including polymer solutions), solubility measurements at near-critical conditions, measurements of critical properties of binary mixtures and their correlation with equations of state. Progress in thermodynamics, coupled with advances in the design and construction of high pressure equipment, has opened up a wide avenue of commercial application (e.g. decaffeination of coffee beans, extractions of flavours and spices, purification of pharmaceutical products, separations of polymeric materials, deodorization and deacidification of vegetable oils, fractionation of fatty acids, coal liquefaction, wood delignitication, etc.)

  5. Ultra-compact TDLAS humidity measurement cell with advanced signal processing

    NASA Astrophysics Data System (ADS)

    Hartmann, A.; Strzoda, R.; Schrobenhauser, R.; Weigel, R.

    2014-05-01

    In this paper, tunable diode laser absorption spectroscopy humidity measurements with an ultra-compact measurement cell are presented. The optical path length is 2 cm. The system uses a vertical cavity surface emitting laser at 1.854 μm. The main limiting factor of the humidity resolution is not the noise but interference fringes produced by reflecting surfaces. Next to the system setup, a novel rejection method to eliminate these fringes, based on Fourier domain analysis of the absorption line, is described. In contrast to other fringe rejection methods, the presented method is able to handle fringes, whose free spectral range is in the range of the half width of the absorption line. The achievable humidity resolution for the presented cell is below 0.25 % relative humidity at room temperature.

  6. Applications of supercritical fluids.

    PubMed

    Brunner, Gerd

    2010-01-01

    This review discusses supercritical fluids in industrial and near-to-industry applications. Supercritical fluids are flexible tools for processing materials. Supercritical fluids have been applied to mass-transfer processes, phase-transition processes, reactive systems, materials-related processes, and nanostructured materials. Some applications are already at industrial capacity, whereas others remain under development. In addition to extraction, application areas include impregnation and cleaning, multistage countercurrent separation, particle formation, coating, and reactive systems such as hydrogenation, biomass gasification, and supercritical water oxidation. Polymers are modified with supercritical fluids, and colloids and emulsions as well as nanostructured materials exhibit interesting phenomena when in contact with supercritical fluids that can be industrially exploited. For these applications to succeed, the properties of supercritical fluids in combination with the materials processed must be clearly determined and fundamental knowledge of the complex behavior must be made readily available. PMID:22432584

  7. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, July 1, 1991--September 30, 1991

    SciTech Connect

    Not Available

    1991-10-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes.

  8. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, October 1, 1991--December 31, 1991

    SciTech Connect

    Not Available

    1992-01-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of solubilization stage of two-stage, catalytic-catalytic liquefaction processes.

  9. The supercritical profile of the supercritical wing

    NASA Technical Reports Server (NTRS)

    Wagner, O.

    1981-01-01

    The profile wing design for supercritical structures is discussed. Emphasis is placed on the flow of air surrounding the wing and variations in flow fields are examined. Modifications to the profile for flight below transonic level are presented that increase the uplift pressure and permit the achievement of critical Mach numbers on the order of 0.85. The uplift pressure along the upper side of the profile is compared for a classical and a Peaky profile. A comparison of classical and supercritical wing cross sections indicates a flatter upper side, a large nose radius, and a thicker profile to the supercritical wing.

  10. A hybrid approach for generating ultra-short bunches for advanced accelerator applications

    NASA Astrophysics Data System (ADS)

    Stratakis, Diktys

    2016-06-01

    Generation of electron beams with high phase-space density, short bunch length and high peak current is an essential requirement for future linear colliders and bright electron beam sources. Unfortunately, such bunches cannot be produced directly from the source since forces from the mutual repulsion of electrons would destroy the brilliance of the beam within a short distance. Here, we detail a beam dynamics study of a two-stage compression scheme that can generate ultra-short bunches without degrading the beam quality. In the first stage, a magnetized beam is compressed with a velocity bunching technique in which the longitudinal phase space is rotated so that electrons on the bunch tail become faster than electrons in the bunch head. In the second stage, the beam is further compressed with a magnetic chicane. With the aid of numerical simulations we show that our two-staged scheme is capable to increase the current of a 50 pC bunch by a notable factor of 100 (from 15 A to 1.5 kA) while the emittance growth can be suppressed to 1% with appropriate tailoring of the initial beam distribution.

  11. Advanced intermediate temperature sodium-nickel chloride batteries with ultra-high energy density

    DOE PAGESBeta

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Yong; Meinhardt, Kerry D.; Chang, Hee -Jung; Canfield, Nathan L.; Sprenkle, Vincent L.

    2016-02-11

    Here we demonstrate for the first time that planar Na-NiCl2 batteries can be operated at an intermediate temperature of 190°C with ultra-high energy density. A specific energy density of 350 Wh/kg, which is 3 times higher than that of conventional tubular Na-NiCl2 batteries operated at 280°C, was obtained for planar Na-NiCl2 batteries operated at 190°C over a long-term cell test (1000 cycles). The high energy density and superior cycle stability are attributed to the slower particle growth of the cathode materials (NaCl and Ni) at 190°C. The results reported in this work demonstrate that planar Na-NiCl2 batteries operated at anmore » intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs.« less

  12. Advanced intermediate temperature sodium-nickel chloride batteries with ultra-high energy density

    NASA Astrophysics Data System (ADS)

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y.; Meinhardt, Kerry D.; Chang, Hee Jung; Canfield, Nathan L.; Sprenkle, Vincent L.

    2016-02-01

    Sodium-metal halide batteries have been considered as one of the more attractive technologies for stationary electrical energy storage, however, they are not used for broader applications despite their relatively well-known redox system. One of the roadblocks hindering market penetration is the high-operating temperature. Here we demonstrate that planar sodium-nickel chloride batteries can be operated at an intermediate temperature of 190 °C with ultra-high energy density. A specific energy density of 350 Wh kg-1, higher than that of conventional tubular sodium-nickel chloride batteries (280 °C), is obtained for planar sodium-nickel chloride batteries operated at 190 °C over a long-term cell test (1,000 cycles), and it attributed to the slower particle growth of the cathode materials at the lower operating temperature. Results reported here demonstrate that planar sodium-nickel chloride batteries operated at an intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs.

  13. Advanced intermediate temperature sodium-nickel chloride batteries with ultra-high energy density.

    PubMed

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y; Meinhardt, Kerry D; Chang, Hee Jung; Canfield, Nathan L; Sprenkle, Vincent L

    2016-01-01

    Sodium-metal halide batteries have been considered as one of the more attractive technologies for stationary electrical energy storage, however, they are not used for broader applications despite their relatively well-known redox system. One of the roadblocks hindering market penetration is the high-operating temperature. Here we demonstrate that planar sodium-nickel chloride batteries can be operated at an intermediate temperature of 190 °C with ultra-high energy density. A specific energy density of 350 Wh kg(-1), higher than that of conventional tubular sodium-nickel chloride batteries (280 °C), is obtained for planar sodium-nickel chloride batteries operated at 190 °C over a long-term cell test (1,000 cycles), and it attributed to the slower particle growth of the cathode materials at the lower operating temperature. Results reported here demonstrate that planar sodium-nickel chloride batteries operated at an intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs. PMID:26864635

  14. Advanced intermediate temperature sodium–nickel chloride batteries with ultra-high energy density

    PubMed Central

    Li, Guosheng; Lu, Xiaochuan; Kim, Jin Y.; Meinhardt, Kerry D.; Chang, Hee Jung; Canfield, Nathan L.; Sprenkle, Vincent L.

    2016-01-01

    Sodium-metal halide batteries have been considered as one of the more attractive technologies for stationary electrical energy storage, however, they are not used for broader applications despite their relatively well-known redox system. One of the roadblocks hindering market penetration is the high-operating temperature. Here we demonstrate that planar sodium–nickel chloride batteries can be operated at an intermediate temperature of 190 °C with ultra-high energy density. A specific energy density of 350 Wh kg−1, higher than that of conventional tubular sodium–nickel chloride batteries (280 °C), is obtained for planar sodium–nickel chloride batteries operated at 190 °C over a long-term cell test (1,000 cycles), and it attributed to the slower particle growth of the cathode materials at the lower operating temperature. Results reported here demonstrate that planar sodium–nickel chloride batteries operated at an intermediate temperature could greatly benefit this traditional energy storage technology by improving battery energy density, cycle life and reducing material costs. PMID:26864635

  15. Ultra sensitive magnetic sensors integrating the giant magnetoelectric effect with advanced microelectronics

    NASA Astrophysics Data System (ADS)

    Fang, Zhao

    This dissertation investigates approaches to enhance the performance, especially the sensitivity and signal to noise ratio of magnetoelectric sensors, which exploits the magnetoelectric coupling in magnetostrictive and piezoelectric laminate composites. A magnetic sensor is a system or device that can measure the magnitude of a magnetic field or each of its vector components. Usually the techniques encompass many aspects of physics and electronics. The common technologies used for magnetic field sensing include induction coil sensors, fluxgate, SQUID (superconducting quantum interference device), Hall effect, giant magnetoresistance, magnetostrictive/piezoelectric composites, and MEMS (microelectromechanical systems)-based magnetic sensors. Magnetic sensors have found a broad range of applications for many decades. For example, ultra sensitive magnetic sensors are able to detect tiny magnetic fields produced outside the brain by the neuronal currents which can be used for diagnostic application. Measuring the brain's magnetic field is extremely challenging because they are so weak, have strengths of 0.1--1 pT and thus requiring magnetic sensors with sub-picotesla sensitivity. In fact, to date, these measurements can only performed with the most sensitive magnetic sensors, i.e., SQUID. However, such detectors need expensive and cumbersome cryogenics to operate. Additionally, the thermal insulation of the sensors prevents them from being placed very closed to the tissues under study, thereby preventing high-resolution measurement capability. All of these severely limit their broad usage and proliferation for biomedical imaging, diagnosis, and research. A novel ultra-sensitive magnetic sensor capable of operating at room temperature is investigated in this thesis. Magnetoelectric effect is a material phenomenon featuring the interchange between the magnetic and electric energies or signals. The large ME effect observed in ME composites, especially the ME laminates

  16. Supercritical fluid extraction

    DOEpatents

    Wai, Chien M.; Laintz, Kenneth

    1994-01-01

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated or lipophilic crown ether or fluorinated dithiocarbamate. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

  17. Electrodeposition from supercritical fluids.

    PubMed

    Bartlett, P N; Cook, D A; George, M W; Hector, A L; Ke, J; Levason, W; Reid, G; Smith, D C; Zhang, W

    2014-05-28

    Recent studies have shown that it is possible to electrodeposit a range of materials, such as Cu, Ag and Ge, from various supercritical fluids, including hydrofluorocarbons and mixtures of CO2 with suitable co-solvents. In this perspective we discuss the relatively new field of electrodeposition from supercritical fluids. The perspective focuses on some of the underlying physical chemistry and covers both practical and scientific aspects of electrodeposition from supercritical fluids. We also discuss possible applications for supercritical fluid electrodeposition and suggest some key developments that are required to take the field to the next stage. PMID:24469309

  18. Liquefaction of coals using ultra-fine particle, unsupported catalysts: In situ generation by rapid expansion of supercritical fluid solutions. Quarterly technical progress report, April 1, 1991--June 30, 1991

    SciTech Connect

    Not Available

    1991-09-01

    The purpose of this program is to design and fabricate an experimental ultra-fine particle generation system; use this system to generate ultra-fine, iron compound, catalyst particles; and to access the ability of these ultra-fine catalyst particles to improve the performance of the solubilization stage of two-stage, catalytic-catalytic liquefaction processes. The effort applied to this program during this reporting period was devoted to experimental design and fabrication tasks.

  19. Advanced Characterization of Soil Organic Matter Using Ultra High Resolution Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Tfaily, M. M.; Chu, R.; Tolic, N.; Roscioli, K.; Robinson, E. R.; Paša-Tolić, L.; Hess, N. J.

    2014-12-01

    The focus on ecosystem stress and climate change is currently relevant as researchers and policymakers strive to understand the feedbacks between soil C dynamics and climate change. Successful development of molecular profiles that link soil microbiology with soil carbon (C) to ascertain soil vulnerability and resilience to climate change would have great impact on assessments of soil ecosystems in response to climate change. Additionally, better understanding of the dynamics of soil organic matter (SOM) plays a central role to climate modeling, and fate and transport of carbon. The use of ultra-high resolution mass spectrometry (UHR MS) has enabled the examination of molecules, directly from mixtures, with ultrahigh mass resolution and sub-ppm mass accuracy. In this study, EMSL's extensive expertise and capabilities in UHR MS proteomics were leveraged to develop extraction protocols for the characterization of carbon compounds in SOM, thereby providing the chemical and structural detail needed to develop mechanistic descriptions of soil carbon flow processes. Our experiments have allowed us to identify thousands of individual compounds in complex soil mixtures with a wide range of C content representing diverse ecosystems within the USA. The yield of the chemical extraction was dependent on (1) the type of solvent used and its polarity, (2) sample-to-solvent ratios and (3) the chemical and physical nature of the samples including their origins. Hexane, a non-polar organic solvent, was efficient in extracting lipid-like compounds regardless of soil origin or organic carbon %. For samples with high organic carbon %, acetonitrile extracted a wide range of compounds characterized with high O/C ratios, identified as polyphenolic compounds that were not observed with methanol extraction. Soils extracted with pyridine showed a similar molecular distribution to those extracted by methanol. Solvent extraction followed by UHR MS is a promising tool to understand the

  20. Advances in high repetition rate, ultra-short, gigawatt laser systems for time-resolved spectroscopy

    SciTech Connect

    DiMauro, L.F.

    1991-12-31

    The objective of this article is to emphasize the current advances in the development of high-repetition rate amplifier pumps. Although this review highlights amplifier pump development, any recent data from achieved outputs via the tunable amplifier section is also discussed. The first section describes desirable parameters attributable to the pump amplifier while the rest of the article deals with specific examples for various options. The pump amplifiers can be characterized into two distinct classes; those achieving operation in the hundred hertz regime and those performing at repetition rates {ge}1kHz. 23 refs., 4 figs.

  1. Advances in high repetition rate, ultra-short, gigawatt laser systems for time-resolved spectroscopy

    SciTech Connect

    DiMauro, L.F.

    1991-01-01

    The objective of this article is to emphasize the current advances in the development of high-repetition rate amplifier pumps. Although this review highlights amplifier pump development, any recent data from achieved outputs via the tunable amplifier section is also discussed. The first section describes desirable parameters attributable to the pump amplifier while the rest of the article deals with specific examples for various options. The pump amplifiers can be characterized into two distinct classes; those achieving operation in the hundred hertz regime and those performing at repetition rates {ge}1kHz. 23 refs., 4 figs.

  2. Advanced Micro Turbine System (AMTS) -C200 Micro Turbine -Ultra-Low Emissions Micro Turbine

    SciTech Connect

    Capstone Turbine Corporation

    2007-12-31

    In September 2000 Capstone Turbine Corporation commenced work on a US Department of Energy contract to develop and improve advanced microturbines for power generation with high electrical efficiency and reduced pollutants. The Advanced MicroTurbine System (AMTS) program focused on: (1) The development and implementation of technology for a 200 kWe scale high efficiency microturbine system (2) The development and implementation of a 65 kWe microturbine which meets California Air Resources Board (CARB) emissions standards effective in 2007. Both of these objectives were achieved in the course of the AMTS program. At its conclusion prototype C200 Microturbines had been designed, assembled and successfully completed field demonstration. C65 Microturbines operating on natural, digester and landfill gas were also developed and successfully tested to demonstrate compliance with CARB 2007 Fossil Fuel Emissions Standards for NOx, CO and VOC emissions. The C65 Microturbine subsequently received approval from CARB under Executive Order DG-018 and was approved for sale in California. The United Technologies Research Center worked in parallel to successfully execute a RD&D program to demonstrate the viability of a low emissions AMS which integrated a high-performing microturbine with Organic Rankine Cycle systems. These results are documented in AMS Final Report DOE/CH/11060-1 dated March 26, 2007.

  3. Programmable Ultra Lightweight System Adaptable Radio (PULSAR) Low Cost Telemetry - Access from Space Advanced Technologies or Down the Middle

    NASA Technical Reports Server (NTRS)

    Sims. Herb; Varnavas, Kosta; Eberly, Eric

    2013-01-01

    Software Defined Radio (SDR) technology has been proven in the commercial sector since the early 1990's. Today's rapid advancement in mobile telephone reliability and power management capabilities exemplifies the effectiveness of the SDR technology for the modern communications market. In contrast, presently qualified satellite transponder applications were developed during the early 1960's space program. Programmable Ultra Lightweight System Adaptable Radio (PULSAR, NASA-MSFC SDR) technology revolutionizes satellite transponder technology by increasing data through-put capability by, at least, an order of magnitude. PULSAR leverages existing Marshall Space Flight Center SDR designs and commercially enhanced capabilities to provide a path to a radiation tolerant SDR transponder. These innovations will (1) reduce the cost of NASA Low Earth Orbit (LEO) and Deep Space transponders, (2) decrease power requirements, and (3) a commensurate volume reduction. Also, PULSAR increases flexibility to implement multiple transponder types by utilizing the same hardware with altered logic - no analog hardware change is required - all of which can be accomplished in orbit. This provides high capability, low cost, transponders to programs of all sizes. The final project outcome would be the introduction of a Technology Readiness Level (TRL) 7 low-cost CubeSat to SmallSat telemetry system into the NASA Portfolio.

  4. Thermal induced flow oscillations in heat exchangers for supercritical fluids

    NASA Technical Reports Server (NTRS)

    Friedly, J. C.; Manganaro, J. L.; Krueger, P. G.

    1972-01-01

    Analytical model has been developed to predict possible unstable behavior in supercritical heat exchangers. From complete model, greatly simplified stability criterion is derived. As result of this criterion, stability of heat exchanger system can be predicted in advance.

  5. SIEMENS ADVANCED QUANTRA FTICR MASS SPECTROMETER FOR ULTRA HIGH RESOLUTION AT LOW MASS

    SciTech Connect

    Spencer, W; Laura Tovo, L

    2008-07-08

    The Siemens Advanced Quantra Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer was evaluated as an alternative instrument to large double focusing mass spectrometers for gas analysis. High resolution mass spectrometers capable of resolving the common mass isomers of the hydrogen isotopes are used to provide data for accurate loading of reservoirs and to monitor separation of tritium, deuterium, and helium. Conventional double focusing magnetic sector instruments have a resolution that is limited to about 5000. The Siemens FTICR instrument achieves resolution beyond 400,000 and could possibly resolve the tritium ion from the helium-3 ion, which differ by the weight of an electron, 0.00549 amu. Working with Y-12 and LANL, SRNL requested Siemens to modify their commercial Quantra system for low mass analysis. To achieve the required performance, Siemens had to increase the available waveform operating frequency from 5 MHz to 40 MHz and completely redesign the control electronics and software. However, they were able to use the previous ion trap, magnet, passive pump, and piezo-electric pulsed inlet valve design. NNSA invested $1M in this project and acquired four systems, two for Y-12 and one each for SRNL and LANL. Siemens claimed a $10M investment in the Quantra systems. The new Siemens Advanced Quantra demonstrated phenomenal resolution in the low mass range. Resolution greater than 400,000 was achieved for mass 2. The new spectrometer had a useful working mass range to 500 Daltons. However, experiments found that a continuous single scan from low mass to high was not possible. Two useful working ranges were established covering masses 1 to 6 and masses 12 to 500 for our studies. A compromise performance condition enabled masses 1 to 45 to be surveyed. The instrument was found to have a dynamic range of about three orders of magnitude and quantitative analysis is expected to be limited to around 5 percent without using complex fitting algorithms

  6. Fatigue and Creep-Fatigue Deformation of an Ultra-Fine Precipitate Strengthened Advanced Austenitic Alloy

    SciTech Connect

    M.C. Carroll; L.J. Carroll

    2012-10-01

    An advanced austenitic alloy, HT-UPS (high-temperature ultrafine-precipitation-strengthened), has been identified as an ideal candidate material for the structural components of fast reactors and energy-conversion systems. HT-UPS alloys demonstrate improved creep resistance relative to 316 stainless steel (SS) through additions of Ti and Nb, which precipitate to form a widespread dispersion of stable nanoscale metallic carbide (MC) particles in the austenitic matrix. The low-cycle fatigue and creep-fatigue behavior of an HT-UPS alloy have been investigated at 650 °C and a 1.0% total strain, with an R-ratio of -1 and hold times at peak tensile strain as long as 150 min. The cyclic deformation response of HT-UPS is directly compared to that of standard 316 SS. The measured values for total cycles to failure are similar, despite differences in peak stress profiles and in qualitative observations of the deformed microstructures. Crack propagation is primarily transgranular in fatigue and creep-fatigue of both alloys at the investigated conditions. Internal grain boundary damage in the form of fine cracks resulting from the tensile hold is present for hold times of 60 min and longer, and substantially more internal cracks are quantifiable in 316 SS than in HT-UPS. The dislocation substructures observed in the deformed material differ significantly; an equiaxed cellular structure is observed in 316 SS, whereas in HT-UPS the microstructure takes the form of widespread and relatively homogenous tangles of dislocations pinned by the nanoscale MC precipitates. The significant effect of the fine distribution of precipitates on observed fatigue and creep-fatigue response is described in three distinct behavioral regions as it evolves with continued cycling.

  7. On the characterization of ultra-precise X-ray optical components: advances and challenges in ex situ metrology.

    PubMed

    Siewert, F; Buchheim, J; Zeschke, T; Störmer, M; Falkenberg, G; Sankari, R

    2014-09-01

    To fully exploit the ultimate source properties of the next-generation light sources, such as free-electron lasers (FELs) and diffraction-limited storage rings (DLSRs), the quality requirements for gratings and reflective synchrotron optics, especially mirrors, have significantly increased. These coherence-preserving optical components for high-brightness sources will feature nanoscopic shape accuracies over macroscopic length scales up to 1000 mm. To enable high efficiency in terms of photon flux, such optics will be coated with application-tailored single or multilayer coatings. Advanced thin-film fabrication of today enables the synthesis of layers on the sub-nanometre precision level over a deposition length of up to 1500 mm. Specifically dedicated metrology instrumentation of comparable accuracy has been developed to characterize such optical elements. Second-generation slope-measuring profilers like the nanometre optical component measuring machine (NOM) at the BESSY-II Optics laboratory allow the inspection of up to 1500 mm-long reflective optical components with an accuracy better than 50 nrad r.m.s. Besides measuring the shape on top of the coated mirror, it is of particular interest to characterize the internal material properties of the mirror coating, which is the domain of X-rays. Layer thickness, density and interface roughness of single and multilayer coatings are investigated by means of X-ray reflectometry. In this publication recent achievements in the field of slope measuring metrology are shown and the characterization of different types of mirror coating demonstrated. Furthermore, upcoming challenges to the inspection of ultra-precise optical components designed to be used in future FEL and DLSR beamlines are discussed. PMID:25177985

  8. Effect of Two Advanced Noise Reduction Technologies on the Aerodynamic Performance of an Ultra High Bypass Ratio Fan

    NASA Technical Reports Server (NTRS)

    Hughes, Christoper E.; Gazzaniga, John A.

    2013-01-01

    A wind tunnel experiment was conducted in the NASA Glenn Research Center anechoic 9- by 15-Foot Low-Speed Wind Tunnel to investigate two new advanced noise reduction technologies in support of the NASA Fundamental Aeronautics Program Subsonic Fixed Wing Project. The goal of the experiment was to demonstrate the noise reduction potential and effect on fan model performance of the two noise reduction technologies in a scale model Ultra-High Bypass turbofan at simulated takeoff and approach aircraft flight speeds. The two novel noise reduction technologies are called Over-the-Rotor acoustic treatment and Soft Vanes. Both technologies were aimed at modifying the local noise source mechanisms of the fan tip vortex/fan case interaction and the rotor wake-stator interaction. For the Over-the-Rotor acoustic treatment, two noise reduction configurations were investigated. The results showed that the two noise reduction technologies, Over-the-Rotor and Soft Vanes, were able to reduce the noise level of the fan model, but the Over-the-Rotor configurations had a significant negative impact on the fan aerodynamic performance; the loss in fan aerodynamic efficiency was between 2.75 to 8.75 percent, depending on configuration, compared to the conventional solid baseline fan case rubstrip also tested. Performance results with the Soft Vanes showed that there was no measurable change in the corrected fan thrust and a 1.8 percent loss in corrected stator vane thrust, which resulted in a total net thrust loss of approximately 0.5 percent compared with the baseline reference stator vane set.

  9. Theoretical models for supercritical fluid extraction.

    PubMed

    Huang, Zhen; Shi, Xiao-Han; Jiang, Wei-Juan

    2012-08-10

    For the proper design of supercritical fluid extraction processes, it is essential to have a sound knowledge of the mass transfer mechanism of the extraction process and the appropriate mathematical representation. In this paper, the advances and applications of kinetic models for describing supercritical fluid extraction from various solid matrices have been presented. The theoretical models overviewed here include the hot ball diffusion, broken and intact cell, shrinking core and some relatively simple models. Mathematical representations of these models have been in detail interpreted as well as their assumptions, parameter identifications and application examples. Extraction process of the analyte solute from the solid matrix by means of supercritical fluid includes the dissolution of the analyte from the solid, the analyte diffusion in the matrix and its transport to the bulk supercritical fluid. Mechanisms involved in a mass transfer model are discussed in terms of external mass transfer resistance, internal mass transfer resistance, solute-solid interactions and axial dispersion. The correlations of the external mass transfer coefficient and axial dispersion coefficient with certain dimensionless numbers are also discussed. Among these models, the broken and intact cell model seems to be the most relevant mathematical model as it is able to provide realistic description of the plant material structure for better understanding the mass-transfer kinetics and thus it has been widely employed for modeling supercritical fluid extraction of natural matters. PMID:22560346

  10. Engineering and Economic Analysis of an Advanced Ultra-Supercritical Pulverized Coal Power Plant with and without Post-Combustion Carbon Capture Task 7. Design and Economic Studies

    SciTech Connect

    Booras, George; Powers, J.; Riley, C.; Hendrix, H.

    2015-09-01

    This report evaluates the economics and performance of two A-USC PC power plants; Case 1 is a conventionally configured A-USC PC power plant with superior emission controls, but without CO2 removal; and Case 2 adds a post-combustion carbon capture (PCC) system to the plant from Case 1, using the design and heat integration strategies from EPRI’s 2015 report, “Best Integrated Coal Plant.” The capture design basis for this case is “partial,” to meet EPA’s proposed New Source Performance Standard, which was initially proposed as 500 kg-CO2/MWh (gross) or 1100 lb-CO2/MWh (gross), but modified in August 2015 to 635 kg-CO2/MWh (gross) or 1400 lb-CO2/MWh (gross). This report draws upon the collective experience of consortium members, with EPRI and General Electric leading the study. General Electric provided the steam cycle analysis as well as v the steam turbine design and cost estimating. EPRI performed integrated plant performance analysis using EPRI’s PC Cost model.

  11. Advances in electronic packaging technologies by ultra-small microvias, super-fine interconnections and low loss polymer dielectrics

    NASA Astrophysics Data System (ADS)

    Sundaram, Venkatesh

    The fundamental motivation for this dissertation is to address the widening interconnect gap between integrated circuit (IC) demands and package substrates specifically for high frequency digital-RF systems applications. Moore's law for CMOS ICs predicts that transistor density on ICs will double approximately every 18 months. Packaging of ICs at the 32nm and 22nm nodes in the next few years will require 20mum (peripheral) and 80mum (area array) I/O pad pitch on the IC, which must be matched by flip-chip interconnection and substrate wiring pad pitch of the same 20-80mum dimension. System on a Package (SOP) technology pioneered by Georgia Tech PRC enables future "mega-function" electronic and bio-electronic systems through ultra-thin film component integration from the current 50/cm2 to over 10000/cm2. This puts added wiring density and performance demands on the substrate. The other driving force in this thesis research is the increasing adoption of high frequency wireless and wired communication pushing the need for package substrate materials that are stable into multiple GHz frequencies. The current state-of-the-art in IC package substrates is at 20mum lines/spaces and 50-60mum microvia diameter using epoxy dielectrics with loss tangent above 0.01. The research targets are to overcome the barriers of current technologies and demonstrate a set of advanced materials and process technologies capable of 5-10mum lines and spaces, and 10-30mum diameter microvias in a multilayer 3-D wiring substrate using 10-25mum thin film dielectrics with loss tangent in the <0.005. The research elements are organized as follows with a clear focus on understanding and characterization of fundamental materials structure-processing-property relationships and interfaces to achieve the next generation targets: (1) Low CTE Core Substrate. (2) Low Loss Dielectrics with 25mum and smaller microvias. (3) Sub-10mum Width Cu Conductors. (4) Integration of the various dielectric and conductor

  12. Supercritical fuel injection system

    NASA Technical Reports Server (NTRS)

    Marek, C. J.; Cooper, L. P. (Inventor)

    1980-01-01

    a fuel injection system for gas turbines is described including a pair of high pressure pumps. The pumps provide fuel and a carrier fluid such as air at pressures above the critical pressure of the fuel. A supercritical mixing chamber mixes the fuel and carrier fluid and the mixture is sprayed into a combustion chamber. The use of fuel and a carrier fluid at supercritical pressures promotes rapid mixing of the fuel in the combustion chamber so as to reduce the formation of pollutants and promote cleaner burning.

  13. Prospects of Supercritical Fluids in Realizing Graphene-Based Functional Materials.

    PubMed

    Padmajan Sasikala, Suchithra; Poulin, Philippe; Aymonier, Cyril

    2016-04-01

    Supercritical-fluids science and technology predate all the approaches that are currently established for graphene production by several decades in advanced materials design. However, it has only recently been proposed as a plausible approach for graphene processing. Since then, supercritical fluids have emerged into contention as an alternative to existing technologies because of their scalability and versatility in processing graphene materials, which include composites, aerogels, and foams. Here, an overview is presented of such materials prepared through supercritical fluids from an advanced materials science standpoint, with a discussion on their fundamental properties and technological applications. The benefits of supercritical-fluid processing over conventional liquid-phase processing are presented. The benefits include not only better performances for advanced applications but also environmental issues associated with the synthesis process. Nevertheless, the limitations of supercritical-fluid processing are also stressed, along with challenges that are still faced toward the achievement of the great expectations from graphene materials. PMID:26879938

  14. Effects of Gravity on Supercritical Water Oxidation (SCWO) Processes

    NASA Technical Reports Server (NTRS)

    Hegde, Uday; Hicks, Michael

    2013-01-01

    The effects of gravity on the fluid mechanics of supercritical water jets are being studied at NASA to develop a better understanding of flow behaviors for purposes of advancing supercritical water oxidation (SCWO) technologies for applications in reduced gravity environments. These studies provide guidance for the development of future SCWO experiments in new experimental platforms that will extend the current operational range of the DECLIC (Device for the Study of Critical Liquids and Crystallization) Facility on board the International Space Station (ISS). The hydrodynamics of supercritical fluid jets is one of the basic unit processes of a SCWO reactor. These hydrodynamics are often complicated by significant changes in the thermo-physical properties that govern flow behavior (e.g., viscosity, thermal conductivity, specific heat, compressibility, etc), particularly when fluids transition from sub-critical to supercritical conditions. Experiments were conducted in a 150 ml reactor cell under constant pressure with water injections at various flow rates. Flow configurations included supercritical jets injected into either sub-critical or supercritical water. Profound gravitational influences were observed, particularly in the transition to turbulence, for the flow conditions under study. These results will be presented and the parameters of the flow that control jet behavior will be examined and discussed.

  15. Supercritical solvent coal extraction

    NASA Technical Reports Server (NTRS)

    Compton, L. E. (Inventor)

    1984-01-01

    Yields of soluble organic extract are increased up to about 50% by the supercritical extraction of particulate coal at a temperature below the polymerization temperature for coal extract fragments (450 C.) and a pressure from 500 psig to 5,000 psig by the conjoint use of a solvent mixture containing a low volatility, high critical temperature coal dissolution catalyst such as phenanthrene and a high volatility, low critical temperature solvent such as toluene.

  16. Supercritical fluids cleaning

    SciTech Connect

    Butner, S.; Hjeresen, D.; Silva, L.; Spall, D.; Stephenson, R.

    1991-01-01

    This paper discusses a proposed multi-party research and development program which seeks to develop supercritical fluid cleaning technology as an alternative to existing solvent cleaning applications. While SCF extraction technology has been in commercial use for several years, the use of these fluids as cleaning agents poses several new technical challenges. Problems inherent in the commercialization of SCF technology include: the cleaning efficacy and compatibility of supercritical working fluids with the parts to be cleaned must be assessed for a variety of materials and components; process parameters and equipment design Have been optimized for extractive applications and must be reconsidered for application to cleaning; and co-solvents and entrainers must be identified to facilitate the removal of polar inorganic and organic contaminants, which are often not well solvated in supercritical systems. The proposed research and development program would address these issues and lead to the development and commercialization of viable SCF-based technology for precision cleaning applications. This paper provides the technical background, program scope, and delineates the responsibilities of each principal participant in the program.

  17. Microemulsions in supercritical hydrochlorofluorocarbons

    SciTech Connect

    Jackson, K.; Fulton, J.L.

    1996-10-30

    We report the properties of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) microemulsions formed in supercritical hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons, and flourocarbons. The fluids used in this study include compounds that are of low toxicity and flammability and that are expected to remain environmentally acceptable well into the next century (e.g., 1,1,1, 2-tetrafluoroethane (R134a) and chlorodifluoromethane (R22)). We show that it is possible to form a water-in-oil type of microemulsion in a low molecular weight HCFC (R22). In addition to these HCFCs, We also review the ability to form microemulsions in 14 other fluids (ethane, propene, propane, n-butane, n-pentane, n-haxane, isobutane, isooctane, difluoromethane, trifluoromethane, hexafluoroethane, sulfur haxafluoride, xenon, and carbon dioxide) at conditions just above or below the critical point (0.75 < T/T{sub c} <1.1) of the solvent. We report extensively the phase behavior of AOT and didodecyldimethylammonium bromide microemulsions formed in a supercritical HCFC, R22. We show that microemulsions in HCFCs are practical alternatives to other fluids, such as supercritical carbon dioxide. 56 refs., 7 figs., 1 tab.

  18. High efficiency supercritical sliding pressure units for oil/gas firing

    SciTech Connect

    Kaneko, S.; Hisatome, M.; Hishida, M.

    1995-12-31

    Mitsubishi Heavy Industries, Ltd. (MHI), the world`s largest power plant manufacturer, has been leading the development of technologies to meet the requirements special to Japanese utility power industry. Mitsubishi supplied a number of supercritical sliding pressure units for firing fuels such as oil, gas and coal, with successful operating performance. In this paper, design features of supercritical sliding pressure operation boiler are reported, considering points for a dual fuel firing boiler, low NO{sub x} firing technologies and the experience of oil and gas-firing supercritical sliding pressure operation boiler represented by the ultra-supercritical pressure gas firing units with steam condition of 31 MPa (316 kgf/cm{sup 2}g), 566/566/566 C.

  19. Advanced processing of gallium nitride and gallium nitride-based devices: Ultra-high temperature annealing and implantation incorporation

    NASA Astrophysics Data System (ADS)

    Yu, Haijiang

    This dissertation is focused on three fields: ultra-high temperature annealing of GaN, activation of implanted GaN and the implantation incorporation into AlGaN/GaN HEMT processing, with an aim to increase the performance, manufacturability and reliability of AlGaN/GaN HEMTs. First, the ultra high temperature (around 1500°C) annealing of MOCVD grown GaN on sapphire has been studied, and a thermally induced threading dislocation (TD) motion and reaction are reported. Using a rapid thermal annealing (RTA) approach capable of heating 2 inch wafers to around 1500°C with 100 bar N2 over-pressure, evidence of dislocation motion was first observed in transmission electron microscopy (TEM) micrographs of both planar and patterned GaN films protected by an AIN capping layer. An associated decrease in x-ray rocking curve (XRC) full-width-half-maximum (FWHM) was also observed for both the symmetric and asymmetric scans. After annealing, the AIN capping layer remained intact, and optical measurements showed no degradation of the opto-electronic properties of the films. Then activation annealing of Si implants in MOCVD grown GaN has been studied for use in ohmic contacts. Si was implanted in semi-insulating GaN at 100 keV with doses from 5 x 1014 cm-2 to 1.5 x 1016 cm-2. Rapid thermal annealing at 1500°C with 100 bar N2 over-pressure was used for dopant activation, resulting in a minimum sheet resistance of 13.9 O/square for a dose of 7 x 1015 cm-2. Secondary ion mass spectroscopy measurements showed a post-activation broadening of the dopant concentration peak by 20 nm (at half the maximum), while X-Ray triple axis o-2theta scans indicated nearly complete implant damage recovery. Transfer length method measurements of the resistance of Ti/Al/Ni/Au contacts to activated GaN:Si (5 x 1015 cm-2 at 100 keV) indicated lowest contact resistances of 0.07 Omm and 0.02 Omm for as-deposited and subsequently annealed contacts, respectively. Finally, the incorporation of Si implantation

  20. Advanced noise reduction techniques for ultra-low phase noise optical-to-microwave division with femtosecond fiber combs.

    PubMed

    Zhang, Wei; Xu, Zhenyu; Lours, Michel; Boudot, Rodolphe; Kersalé, Yann; Luiten, Andre N; Le Coq, Yann; Santarelli, Giorgio

    2011-05-01

    We report what we believe to be the lowest phase noise optical-to-microwave frequency division using fiber-based femtosecond optical frequency combs: a residual phase noise of -120 dBc/Hz at 1 Hz offset from an 11.55 GHz carrier frequency. Furthermore, we report a detailed investigation into the fundamental noise sources which affect the division process itself. Two frequency combs with quasi-identical configurations are referenced to a common ultrastable cavity laser source. To identify each of the limiting effects, we implement an ultra-low noise carrier-suppression measurement system, which avoids the detection and amplification noise of more conventional techniques. This technique suppresses these unwanted sources of noise to very low levels. In the Fourier frequency range of ∼200 Hz to 100 kHz, a feed-forward technique based on a voltage-controlled phase shifter delivers a further noise reduction of 10 dB. For lower Fourier frequencies, optical power stabilization is implemented to reduce the relative intensity noise which causes unwanted phase noise through power-to-phase conversion in the detector. We implement and compare two possible control schemes based on an acousto-optical modulator and comb pump current. We also present wideband measurements of the relative intensity noise of the fiber comb. PMID:21622045

  1. Alloys for advanced steam turbines--Oxidation behavior

    SciTech Connect

    Holcomb, G.R.

    2007-10-01

    Advanced or ultra supercritical (USC) steam power plants offer the promise of higher efficiencies and lower emissions. Current goals of the U.S. Department of Energy (DOE) include power generation from coal at 60% efficiency, which would require steam temperatures of up to 760°C. Current research on the oxidation of candidate materials for advanced steam turbines is presented with a focus on a methodology for estimating chromium evaporation rates from protective chromia scales. The high velocities and pressures of advanced steam turbines lead to evaporation predictions as high as 5 × 10-8 kg m-2s-1 of CrO2(OH)2(g) at 760°C and 34.5 MPa. This is equivalent to 0.077 mm per year of solid Cr loss.

  2. Supercritical water oxidation for destruction of polycyclic aromatic hydrocarbons

    SciTech Connect

    Kocher, B.S.; Fullerton, K.L.; Lee, S.

    1994-12-31

    Polycyclic aromatic hydrocarbons (PAHs) represent a large class of hydrocarbons that are considered hazardous to the environment. Large amount of PAHs have been dumped onto open ground in cases such as Town gas sites. These sites represent a major environmental liability due to the difficulty in removing them by conventional methods and the large amount of sites, more than 2,000. Supercritical water oxidation offers a unique method of both removing the contaminates and destroying them in a single stage processing step. The process utilizes the single phase mixture of water and oxygen at supercritical water conditions. This allows for the PAHs to be extracted and destroyed simultaneously. The reaction produces an effluent stream rich in carbon dioxide and water. Town gas soil containing 3.37 wt% contamination was ultra-cleaned in a 1-liter pilot plant to an environmentally acceptable level of less than 200 ppm.

  3. Supercritical steam in power production--A materials review

    SciTech Connect

    Holcomb, Gordon R.; Covino, Bernard S., Jr.; Alman, David E.; Bullard, Sophie J.; Cramer, Stephen D.; Ziomek-Moroz, Margaret

    2004-01-01

    The use of higher temperatures and higher pressures in steam boilers and turbines allows for increased efficiencies, which increases the amount of energy and decreases the emissions from a given amount of fuel. Extensive development of high strength ferritic steels has occurred, and is continuing, for use in boilers and turbines. Ferritic steels are widely used with steam temperatures of 565 C. The limit for ferritic steels is believed to be about 650 C. Research efforts throughout the world are underway to increase steam temperatures to 650 C, 700 C, and 760 C using ferritic steels, austenitic steels, high-nickel alloys, and nickel-based superalloys. Selected topics are presented to provide a background into the development of ultra supercritical power generation, including background on boiler systems, water properties, the steam cycle, worldwide research efforts, materials requirements, proposed alloys, and corrosion in supercritical steam.

  4. Particle Formation and Product Formulation Using Supercritical Fluids.

    PubMed

    Knez, Željko; Knez Hrnčič, Maša; Škerget, Mojca

    2015-01-01

    Traditional methods for solids processing involve either high temperatures, necessary for melting or viscosity reduction, or hazardous organic solvents. Owing to the negative impact of the solvents on the environment, especially on living organisms, intensive research has focused on new, sustainable methods for the processing of these substances. Applying supercritical fluids for particle formation may produce powders and composites with special characteristics. Several processes for formation and design of solid particles using dense gases have been studied intensively. The unique thermodynamic and fluid-dynamic properties of supercritical fluids can be used also for impregnation of solid particles or for the formation of solid powderous emulsions and particle coating, e.g., for formation of solids with unique properties for use in different applications. We give an overview of the application of sub- and supercritical fluids as green processing media for particle formation processes and present recent advances and trends in development. PMID:26091976

  5. Corrosion in supercritical fluids

    SciTech Connect

    Propp, W.A.; Carleson, T.E.; Wai, Chen M.; Taylor, P.R.; Daehling, K.W.; Huang, Shaoping; Abdel-Latif, M.

    1996-05-01

    Integrated studies were carried out in the areas of corrosion, thermodynamic modeling, and electrochemistry under pressure and temperature conditions appropriate for potential applications of supercritical fluid (SCF) extractive metallurgy. Carbon dioxide and water were the primary fluids studied. Modifiers were used in some tests; these consisted of 1 wt% water and 10 wt% methanol for carbon dioxide and of sulfuric acid, sodium sulfate, ammonium sulfate, and ammonium nitrate at concentrations ranging from 0.00517 to 0.010 M for the aqueous fluids. The materials studied were Types 304 and 316 (UNS S30400 and S31600) stainless steel, iron, and AISI-SAE 1080 (UNS G10800) carbon steel. The thermodynamic modeling consisted of development of a personal computer-based program for generating Pourbaix diagrams at supercritical conditions in aqueous systems. As part of the model, a general method for extrapolating entropies and related thermodynamic properties from ambient to SCF conditions was developed. The experimental work was used as a tool to evaluate the predictions of the model for these systems. The model predicted a general loss of passivation in iron-based alloys at SCF conditions that was consistent with experimentally measured corrosion rates and open circuit potentials. For carbon-dioxide-based SCFs, measured corrosion rates were low, indicating that carbon steel would be suitable for use with unmodified carbon dioxide, while Type 304 stainless steel would be suitable for use with water or methanol as modifiers.

  6. Supercritical fluid processing: opportunities for new resist materials and processes

    NASA Astrophysics Data System (ADS)

    Gallagher-Wetmore, Paula M.; Ober, Christopher K.; Gabor, Allen H.; Allen, Robert D.

    1996-05-01

    Over the past two decades supercritical fluids have been utilized as solvents for carrying out separations of materials as diverse as foods, polymers, pharmaceuticals, petrochemicals, natural products, and explosives. More recently they have been used for non-extractive applications such as recrystallization, deposition, impregnation, surface modification, and as a solvent alternative for precision parts cleaning. Today, supercritical fluid extraction is being practiced in the foods and beverage industries; there are commercial plants for decaffeinating coffee and tea, extracting beer flavoring agents from hops, and separating oils and oleoresins from spices. Interest in supercritical fluid processing of polymers has grown over the last ten years, and many new purification, fractionation, and even polymerization techniques have emerged. One of the most significant motivations for applying this technology to polymers has been increased performance demands. More recently, with increasing scrutiny of traditional solvents, supercritical fluids, and in particular carbon dioxide, are receiving widespread attention as 'environmentally conscious' solvents. This paper describes several examples of polymers applications, including a few involving photoresists, which demonstrate that as next- generation advanced polymer systems emerge, supercritical fluids are certain to offer advantages as cutting edge processing tools.

  7. Analysis of advanced glycation endproducts in selected food items by ultra-performance liquid chromatography tandem mass spectrometry: Presentation of a dietary AGE database.

    PubMed

    Scheijen, Jean L J M; Clevers, Egbert; Engelen, Lian; Dagnelie, Pieter C; Brouns, Fred; Stehouwer, Coen D A; Schalkwijk, Casper G

    2016-01-01

    The aim of this study was to validate an ultra-performance liquid chromatography tandem mass-spectrometry (UPLC-MS/MS) method for the determination of advanced glycation endproducts (AGEs) in food items and to analyze AGEs in a selection of food items commonly consumed in a Western diet. N(ε)-(carboxymethyl)lysine (CML), N(ε)-(1-carboxyethyl)lysine (CEL) and N(δ)-(5-hydro-5-methyl-4-imidazolon-2-yl)-ornithine (MG-H1) were quantified in the protein fractions of 190 food items using UPLC-MS/MS. Intra- and inter-day accuracy and precision were 2-29%. The calibration curves showed perfect linearity in water and food matrices. We found the highest AGE levels in high-heat processed nut or grain products, and canned meats. Fruits, vegetables, butter and coffee had the lowest AGE content. The described method proved to be suitable for the quantification of three major AGEs in food items. The presented dietary AGE database opens the possibility to further quantify actual dietary exposure to AGEs and to explore its physiological impact on human health. PMID:26213088

  8. Supercritical Brayton Cycle Nuclear Power System Concepts

    SciTech Connect

    Wright, Steven A.

    2007-01-30

    Both the NASA and DOE have programs that are investigating advanced power conversion cycles for planetary surface power on the moon or Mars, and for next generation nuclear power plants on earth. The gas Brayton cycle offers many practical solutions for space nuclear power systems and was selected as the nuclear power system of choice for the NASA Prometheus project. An alternative Brayton cycle that offers high efficiency at a lower reactor coolant outlet temperature is the supercritical Brayton cycle (SCBC). The supercritical cycle is a true Brayton cycle because it uses a single phase fluid with a compressor inlet temperature that is just above the critical point of the fluid. This paper describes the use of a supercritical Brayton cycle that achieves a cycle efficiency of 26.6% with a peak coolant temperature of 750 K and for a compressor inlet temperature of 390 K. The working fluid uses a clear odorless, nontoxic refrigerant C318 perflurocarbon (C4F8) that always operates in the gas phase. This coolant was selected because it has a critical temperature and pressure of 388.38 K and 2.777 MPa. The relatively high critical temperature allows for efficient thermal radiation that keeps the radiator mass small. The SCBC achieves high efficiency because the loop design takes advantage of the non-ideal nature of the coolant equation of state just above the critical point. The lower coolant temperature means that metal fuels, uranium oxide fuels, and uranium zirconium hydride fuels with stainless steel, ferretic steel, or superalloy cladding can be used with little mass penalty or reduction in cycle efficiency. The reactor can use liquid-metal coolants and no high temperature heat exchangers need to be developed. Indirect gas cooling or perhaps even direct gas cooling can be used if the C4F8 coolant is found to be sufficiently radiation tolerant. Other fluids can also be used in the supercritical Brayton cycle including Propane (C3H8, Tcritical = 369 K) and Hexane (C6

  9. Supercritical Brayton Cycle Nuclear Power System Concepts

    NASA Astrophysics Data System (ADS)

    Wright, Steven A.

    2007-01-01

    Both the NASA and DOE have programs that are investigating advanced power conversion cycles for planetary surface power on the moon or Mars, and for next generation nuclear power plants on earth. The gas Brayton cycle offers many practical solutions for space nuclear power systems and was selected as the nuclear power system of choice for the NASA Prometheus project. An alternative Brayton cycle that offers high efficiency at a lower reactor coolant outlet temperature is the supercritical Brayton cycle (SCBC). The supercritical cycle is a true Brayton cycle because it uses a single phase fluid with a compressor inlet temperature that is just above the critical point of the fluid. This paper describes the use of a supercritical Brayton cycle that achieves a cycle efficiency of 26.6% with a peak coolant temperature of 750 K and for a compressor inlet temperature of 390 K. The working fluid uses a clear odorless, nontoxic refrigerant C318 perflurocarbon (C4F8) that always operates in the gas phase. This coolant was selected because it has a critical temperature and pressure of 388.38 K and 2.777 MPa. The relatively high critical temperature allows for efficient thermal radiation that keeps the radiator mass small. The SCBC achieves high efficiency because the loop design takes advantage of the non-ideal nature of the coolant equation of state just above the critical point. The lower coolant temperature means that metal fuels, uranium oxide fuels, and uranium zirconium hydride fuels with stainless steel, ferretic steel, or superalloy cladding can be used with little mass penalty or reduction in cycle efficiency. The reactor can use liquid-metal coolants and no high temperature heat exchangers need to be developed. Indirect gas cooling or perhaps even direct gas cooling can be used if the C4F8 coolant is found to be sufficiently radiation tolerant. Other fluids can also be used in the supercritical Brayton cycle including Propane (C3H8, Tcritical = 369 K) and Hexane (C6

  10. Effect of Maximum Cruise-power Operation at Ultra-lean Mixture and Increased Spark Advance on the Mechanical Condition of Cylinder Components

    NASA Technical Reports Server (NTRS)

    Harris, Herbert B.; Duffy, Robert T.; Erwin, Robert D., Jr.

    1945-01-01

    A continuous 50-hour test was conducted to determine the effect of maximum cruise-power operation at ultra-lean fuel-air mixture and increased spark advance on the mechanical conditions of cylinder components. The test was conducted on a nine-cylinder air-cooled radial engine at the following conditions:brake horsepower, 750; engine speed, 1900 rpm; brake mean effective pressure, 172 pounds per square inch; fuel-air ratio, 0.052; spark advance, 30 deg B.T.C.; and maximum rear-spark-plug-bushing temperature, 400 F. In addition to the data on corrosion and wear, data are presented and briefly discussed on the effect of engine operation at the conditions of this test on economy, knock, preignition, and mixture distribution. Cylinder, piston, and piston-ring wear was small and all cylinder component were in good condition at the conclusion of the 50-hour test except that all exhaust-valve guides were bellmouthed beyond the Army's specified limit and one exhaust-valve face was lightly burned. It is improbable that the light burning in one spot of the valve face would have progressed further because the burn was filled with a hard deposit so that the valve face formed an unbroken seal and the mating seat showed no evidence of burning. The bellmouthing of the exhaust-valve guides is believed to have been a result of the heavy carbon and lead-oxide deposits, which were present on the head end of the guided length of the exhaust-valve stem. Engine operational the conditions of this test was shown to result In a fuel saving of 16.8 percent on a cooled-power basis as compared with operation at the conditions recommended for this engine by the Army Air Forces for the same power.

  11. Final LDRD report : design and fabrication of advanced device structures for ultra high efficiency solid state lighting.

    SciTech Connect

    Koleske, Daniel David; Bogart, Katherine Huderle Andersen; Shul, Randy John; Wendt, Joel Robert; Crawford, Mary Hagerott; Allerman, Andrew Alan; Fischer, Arthur Joseph

    2005-04-01

    The goal of this one year LDRD was to improve the overall efficiency of InGaN LEDs by improving the extraction of light from the semiconductor chip. InGaN LEDs are currently the most promising technology for producing high efficiency blue and green semiconductor light emitters. Improving the efficiency of InGaN LEDs will enable a more rapid adoption of semiconductor based lighting. In this LDRD, we proposed to develop photonic structures to improve light extraction from nitride-based light emitting diodes (LEDs). While many advanced device geometries were considered for this work, we focused on the use of a photonic crystal for improved light extraction. Although resonant cavity LEDs and other advanced structures certainly have the potential to improve light extraction, the photonic crystal approach showed the most promise in the early stages of this short program. The photonic crystal (PX)-LED developed here incorporates a two dimensional photonic crystal, or photonic lattice, into a nitride-based LED. The dimensions of the photonic crystal are selected such that there are very few or no optical modes in the plane of the LED ('lateral' modes). This will reduce or eliminate any radiation in the lateral direction so that the majority of the LED radiation will be in vertical modes that escape the semiconductor, which will improve the light-extraction efficiency. PX-LEDs were fabricated using a range of hole diameters and lattice constants and compared to control LEDs without a photonic crystal. The far field patterns from the PX-LEDs were dramatically modified by the presence of the photonic crystal. An increase in LED brightness of 1.75X was observed for light measured into a 40 degree emission cone with a total increase in power of 1.5X for an unencapsulated LED.

  12. Conceptual design of a thermalhydraulic loop for multiple test geometries at supercritical conditions named Supercritical Phenomena Experimental Test Apparatus (SPETA)

    NASA Astrophysics Data System (ADS)

    Adenariwo, Adepoju

    The efficiency of nuclear reactors can be improved by increasing the operating pressure of current nuclear reactors. Current CANDU-type nuclear reactors use heavy water as coolant at an outlet pressure of up to 11.5 MPa. Conceptual SuperCritical Water Reactors (SCWRs) will operate at a higher coolant outlet pressure of 25 MPa. Supercritical water technology has been used in advanced coal plants and its application proves promising to be employed in nuclear reactors. To better understand how supercritical water technology can be applied in nuclear power plants, supercritical water loops are used to study the heat transfer phenomena as it applies to CANDU-type reactors. A conceptual design of a loop known as the Supercritical Phenomena Experimental Apparatus (SPETA) has been done. This loop has been designed to fit in a 9 m by 2 m by 2.8 m enclosure that will be installed at the University of Ontario Institute of Technology Energy Research Laboratory. The loop include components to safely start up and shut down various test sections, produce a heat source to the test section, and to remove reject heat. It is expected that loop will be able to investigate the behaviour of supercritical water in various geometries including bare tubes, annulus tubes, and multi-element-type bundles. The experimental geometries are designed to match the fluid properties of Canadian SCWR fuel channel designs so that they are representative of a practical application of supercritical water technology in nuclear plants. This loop will investigate various test section orientations which are the horizontal, vertical, and inclined to investigate buoyancy effects. Frictional pressure drop effects and satisfactory methods of estimating hydraulic resistances in supercritical fluid shall also be estimated with the loop. Operating limits for SPETA have been established to be able to capture the important heat transfer phenomena at supercritical conditions. Heat balance and flow calculations have

  13. Supercritical fluids: Reactions, materials and applications

    SciTech Connect

    Tumas, W.; Jacobson, G.B.; Josephsohn, N.S.; Brown, G.H.

    1999-04-09

    A number of important processes utilizing supercritical fluids have been either implemented or are emerging for extractions, separations and a wide range of cleaning applications. Supercritical fluids can be reasonable solvents yet share many of the advantages of gases including miscibility with other gases (i.e. hydrogen and oxygen), low viscosities and high diffusivities. Carbon dioxide has the further advantages of being nontoxic, nonflammable, inexpensive and currently unregulated. The use of compressed gases, either as liquids or supercritical fluids, as reaction media offers the opportunity to replace conventional hazardous solvents and also to optimize and potentially control the effect of solvent on chemical and material processing. The last several years has seen a significant growth in advances in chemical synthesis, catalytic transformations and materials synthesis and processing. The authors report on results from an exploratory program at Los Alamos National Laboratory aimed at investigating the use of dense phase fluids, particularly carbon dioxide, as reaction media for homogeneous, heterogeneous and phase-separable catalytic reactions in an effort to develop new, environmentally-friendly methods for chemical synthesis and processing. This approach offers the possibility of opening up substantially different chemical pathways, increasing selectivity at higher reaction rates, facilitating downstream separations and mitigating the need for hazardous solvents. Developing and understanding chemical and catalytic transformations in carbon dioxide could lead to greener chemistry at three levels: (1) Solvent replacement; (2) Better chemistry (e.g. higher reactivity, selectivity, less energy consumption); and (3) New chemistry (e.g. novel separations, use of COP{sub 2} as a C-1 source).

  14. Effect of Boron on the Hot Ductility Behavior of a Low Carbon Advanced Ultra-High Strength Steel (A-UHSS)

    NASA Astrophysics Data System (ADS)

    Mejía, Ignacio; Altamirano, Gerardo; Bedolla-Jacuinde, Arnoldo; Cabrera, José María

    2013-11-01

    This research work studied the effect of boron additions (14, 33, 82, 126, and 214 ppm) on the hot ductility behavior of a low carbon advanced ultra-high strength steel. For this purpose, specimens were subjected to a hot tensile test at different temperatures [923 K, 973 K, 1023 K, 1073 K, 1173 K, and 1273 K (650 °C, 700 °C, 750 °C, 800 °C, 900 °C, and 1000 °C)] under a constant true strain rate of 10-3 s-1. The reduction of area (RA) of the tested samples until fracture was taken as a measure of the hot ductility. In general, results revealed a marked improvement in hot ductility from 82 ppm B when the stoichiometric composition for BN (0.8:1) was exceeded. By comparing the ductility curve of the steel with the highest boron content (B5, 214 ppm B) and the curve for the steel without boron (B0), the increase of hot ductility in terms of RA is over 100 pct. In contrast, the typical recovery of hot ductility at temperatures below the Ar3, where large amounts of normal transformation ferrite usually form in the structure, was not observed in these steels. On the other hand, the fracture surfaces indicated that the fracture mode tends to be more ductile as the boron content increases. It was shown that precipitates and/or inclusions coupled with voids play a meaningful role on the crack nucleation mechanism, which in turn causes hot ductility loss. In general, results are discussed in terms of boron segregation and precipitation on austenitic grain boundaries during cooling from the austenitic range and subsequent plastic deformation.

  15. On the characterization of ultra-precise X-ray optical components: advances and challenges in ex situ metrology

    PubMed Central

    Siewert, F.; Buchheim, J.; Zeschke, T.; Störmer, M.; Falkenberg, G.; Sankari, R.

    2014-01-01

    To fully exploit the ultimate source properties of the next-generation light sources, such as free-electron lasers (FELs) and diffraction-limited storage rings (DLSRs), the quality requirements for gratings and reflective synchrotron optics, especially mirrors, have significantly increased. These coherence-preserving optical components for high-brightness sources will feature nanoscopic shape accuracies over macroscopic length scales up to 1000 mm. To enable high efficiency in terms of photon flux, such optics will be coated with application-tailored single or multilayer coatings. Advanced thin-film fabrication of today enables the synthesis of layers on the sub-nanometre precision level over a deposition length of up to 1500 mm. Specifically dedicated metrology instrumentation of comparable accuracy has been developed to characterize such optical elements. Second-generation slope-measuring profilers like the nanometre optical component measuring machine (NOM) at the BESSY-II Optics laboratory allow the inspection of up to 1500 mm-long reflective optical components with an accuracy better than 50 nrad r.m.s. Besides measuring the shape on top of the coated mirror, it is of particular interest to characterize the internal material properties of the mirror coating, which is the domain of X-rays. Layer thickness, density and interface roughness of single and multilayer coatings are investigated by means of X-ray reflectometry. In this publication recent achievements in the field of slope measuring metrology are shown and the characterization of different types of mirror coating demonstrated. Furthermore, upcoming challenges to the inspection of ultra-precise optical components designed to be used in future FEL and DLSR beamlines are discussed. PMID:25177985

  16. Supercritical microgravity droplet vaporization

    NASA Technical Reports Server (NTRS)

    Hartfield, J.; Curtis, E.; Farrell, P.

    1990-01-01

    Supercritical droplet vaporization is an important issue in many combustion systems, such as liquid fueled rockets and compression-ignition (diesel) engines. In order to study the details of droplet behavior at these conditions, an experiment was designed to provide a gas phase environment which is above the critical pressure and critical temperature of a single liquid droplet. In general, the droplet begins as a cold droplet in the hot, high pressure environment. In order to eliminate disruptions to the droplet by convective motion in the gas, forced and natural convection gas motion are required to be small. Implementation of this requirement for forced convection is straightforward, while reduction of natural convection is achieved by reduction in the g-level for the experiment. The resulting experiment consists of a rig which can stably position a droplet without restraint in a high-pressure, high temperature gas field in microgravity. The microgravity field is currently achieved by dropping the device in the NASA Lewis 2.2 second drop tower. The performance of the experimental device and results to date are presented.

  17. Resolving Supercritical Orion Cores

    NASA Astrophysics Data System (ADS)

    Li, Di; Chapman, N.; Goldsmith, P.; Velusamy, T.

    2009-01-01

    The theoretical framework for high mass star formation (HMSF) is unclear. Observations reveal a seeming dichotomy between high- and low-mass star formation, with HMSF occurring only in Giant Molecular Clouds (GMC), mostly in clusters, and with higher star formation efficiencies than low-mass star formation. One crucial constraint to any theoretical model is the dynamical state of massive cores, in particular, whether a massive core is in supercritical collapse. Based on the mass-size relation of dust emission, we select likely unstable targets from a sample of massive cores (Li et al. 2007 ApJ 655, 351) in the nearest GMC, Orion. We have obtained N2H+ (1-0) maps using CARMA with resolution ( 2.5", 0.006 pc) significantly better than existing observations. We present observational and modeling results for ORI22. By revealing the dynamic structure down to Jeans scale, CARMA data confirms the dominance of gravity over turbulence in this cores. This work was performed by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  18. Operation and analysis of a supercritical CO2 Brayton cycle.

    SciTech Connect

    Wright, Steven Alan; Radel, Ross F.; Vernon, Milton E.; Pickard, Paul S.; Rochau, Gary Eugene

    2010-09-01

    Sandia National Laboratories is investigating advanced Brayton cycles using supercritical working fluids for use with solar, nuclear or fossil heat sources. The focus of this work has been on the supercritical CO{sub 2} cycle (S-CO2) which has the potential for high efficiency in the temperature range of interest for these heat sources, and is also very compact, with the potential for lower capital costs. The first step in the development of these advanced cycles was the construction of a small scale Brayton cycle loop, funded by the Laboratory Directed Research & Development program, to study the key issue of compression near the critical point of CO{sub 2}. This document outlines the design of the small scale loop, describes the major components, presents models of system performance, including losses, leakage, windage, compressor performance, and flow map predictions, and finally describes the experimental results that have been generated.

  19. Next Generation Engineered Materials for Ultra Supercritical Steam Turbines

    SciTech Connect

    Douglas Arrell

    2006-05-31

    To reduce the effect of global warming on our climate, the levels of CO{sub 2} emissions should be reduced. One way to do this is to increase the efficiency of electricity production from fossil fuels. This will in turn reduce the amount of CO{sub 2} emissions for a given power output. Using US practice for efficiency calculations, then a move from a typical US plant running at 37% efficiency to a 760 C /38.5 MPa (1400 F/5580 psi) plant running at 48% efficiency would reduce CO2 emissions by 170kg/MW.hr or 25%. This report presents a literature review and roadmap for the materials development required to produce a 760 C (1400 F) / 38.5MPa (5580 psi) steam turbine without use of cooling steam to reduce the material temperature. The report reviews the materials solutions available for operation in components exposed to temperatures in the range of 600 to 760 C, i.e. above the current range of operating conditions for today's turbines. A roadmap of the timescale and approximate cost for carrying out the required development is also included. The nano-structured austenitic alloy CF8C+ was investigated during the program, and the mechanical behavior of this alloy is presented and discussed as an illustration of the potential benefits available from nano-control of the material structure.

  20. Research activities on supercritical fluid science in food biotechnology.

    PubMed

    Khosravi-Darani, Kianoush

    2010-06-01

    This article serves as an overview, introducing the currently popular area of supercritical fluids and their uses in food biotechnology. Within each application, and wherever possible, the basic principles of the technique, as well as a description of the history, instrumentation, methodology, uses, problems encountered, and advantages over the traditional, non-supercritical methods are given. Most current commercial application of the supercritical extraction involve biologically-produced materials; the technique may be particularly relevant to the extraction of biological compounds in cases where there is a requirement for low-temperature processing, high mass-transfer rates, and negligible carrying over of the solvent into the final product. Special applications to food processing include the decaffeination of green coffee beans, the production of hops extracts, the recovery of aromas and flavors from herbs and spices, the extraction and fractionation of edible oils, and the removal of contaminants, among others. New advances, in which the extraction is combined with reaction or crystallization steps, may further increase the attractiveness of supercritical fluids in the bioprocess industries. To develop and establish a novel and effective alternative to heating treatment, the lethal action of high hydrostatic pressure CO(2) on microorganisms, with none or only a minimal heating process, has recently received a great deal of attention. PMID:20544439

  1. Supercritical Fluid Reactions for Coal Processing

    SciTech Connect

    Charles A. Eckert

    1997-11-01

    Exciting opportunities exist for the application of supercritical fluid (SCF) reactions for the pre-treatment of coal. Utilizing reactants which resemble the organic nitrogen containing components of coal, we developed a method to tailor chemical reactions in supercritical fluid solvents for the specific application of coal denitrogenation. The tautomeric equilibrium of a Schiff base was chosen as one model system and was investigated in supercritical ethane and cosolvent modified supercritical ethane. The Diels-Alder reaction of anthracene and 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) was selected as a second model system, and it was investigated in supercritical carbon dioxide.

  2. Steam Oxidation of Advanced Steam Turbine Alloys

    SciTech Connect

    Holcomb, Gordon R.

    2008-01-01

    Power generation from coal using ultra supercritical steam results in improved fuel efficiency and decreased greenhouse gas emissions. Results of ongoing research into the oxidation of candidate nickel-base alloys for ultra supercritical steam turbines are presented. Exposure conditions range from moist air at atmospheric pressure (650°C to 800°C) to steam at 34.5 MPa (650°C to 760°C). Parabolic scale growth coupled with internal oxidation and reactive evaporation of chromia are the primary corrosion mechanisms.

  3. Supercritical droplet combustion and related transport phenomena

    NASA Technical Reports Server (NTRS)

    Yang, Vigor; Hsieh, K. C.; Shuen, J. S.

    1993-01-01

    An overview of recent advances in theoretical analyses of supercritical droplet vaporization and combustion is conducted. Both hydrocarbon and cryogenic liquid droplets over a wide range of thermodynamic states are considered. Various important high-pressure effects on droplet behavior, such as thermodynamic non-ideality, transport anomaly, and property variation, are reviewed. Results indicate that the ambient gas pressure exerts significant control of droplet gasification and burning processes through its influence on fluid transport, gas-liquid interfacial thermodynamics, and chemical reactions. The droplet gasification rate increases progressively with pressure. However, the data for the overall burnout time exhibit a considerable change in the combustion mechanism at the criticl pressure, mainly as a result of reduced mass diffusivity and latent heat of vaporization with increased pressure. The influence of droplet size on the burning characteristics is also noted.

  4. Engineering development of advanced coal-fired low emission boiler systems

    SciTech Connect

    Not Available

    1993-10-01

    Riley Stoker Corporation is leading an R&D program for the expedited development of a new generation of pulverized coal-fired boiler systems. The overall objective is to develop relatively near term technologies to produce Low-Emission coal-fired Boiler Systems (LEBS) ready for full scale commercial generating plants by the end of the decade. The specific goal is to develop a LEBS incorporating an advanced slagging system for improved ash management in addition to meeting the emission and performance goals. This Concept Selection Report documents an evaluation of subsystems and LEBS concepts. Priority was given to the evaluation of the boiler system, steam cycle, and advanced slagging combustor. Some findings are as follows: An ultra supercritical steam cycle is required to meet project efficiency goals. The cost of electricity (COE) for this cycle, at today`s fuel prices, and without externality costs, is slightly higher than a conventional subcritical cycle. The supercritical cycle includes a substantial contingency. Reduction of contingency, escalation of fuel cost, or inclusion of externalities all lead to a lower COE for the supercritical cycle compared to the subcritical cycle. The advanced cycle is selected for inclusion in the LEBS. The advanced slagging combustor (TVC), should it meet the projected performance goals, yields a lower COE than either a dry firing system or a more conventional slagger fitted with post combustion NO{sub x} controls. Verification and development of the advanced slagger performance is the primary focus of this project. A commercial slagging configuration know as U-firing is selected for parallel development and as a platform for adaptation to the TVC.

  5. Supercritical multicomponent solvent coal extraction

    NASA Technical Reports Server (NTRS)

    Corcoran, W. H.; Fong, W. S.; Pichaichanarong, P.; Chan, P. C. F.; Lawson, D. D. (Inventor)

    1983-01-01

    The yield of organic extract from the supercritical extraction of coal with larger diameter organic solvents such as toluene is increased by use of a minor amount of from 0.1 to 10% by weight of a second solvent such as methanol having a molecular diameter significantly smaller than the average pore diameter of the coal.

  6. Removing Solids From Supercritical Water

    NASA Technical Reports Server (NTRS)

    Hong, Glenn T.

    1992-01-01

    Apparatus removes precipitated inorganic salts and other solids in water-recycling process. Designed for use with oxidation in supercritical water which treats wastes and yields nearly pure water. Heating coils and insulation around vessel keep it hot. Locking bracket seals vessel but allows it to be easily opened for replacement of filled canisters.

  7. Simulated propeller slipstream effects on a supercritical wing

    NASA Technical Reports Server (NTRS)

    Welge, H. R.; Crowder, J. P.

    1978-01-01

    To quantify the installed performance of high speed (M = 0.8) turboprop propulsion systems, an experimental program designed to assess the magnitude of the aerodynamic interference of a propeller slipstream on a supercritical wing has been conducted. The test was conducted in the NASA Ames 14-foot wind tunnel. An ejector-nacelle propeller slipstream simulator was used to produce a slipstream with characteristics typical of advanced propellers presently being investigated. A supercritical wing-body configuration was used to evaluate the interference effects. A traversing total pressure rake was used to make flow field measurements behind the wing and to calibrate the slipstream simulator. The force results indicated that the interference drag amounted to an increase of ten counts or about 3% of the wing-body drag for a two engine configuration at the nominal propeller operating conditions. However, at the higher swirl angles (11 deg vs. 7 deg nominally) the interference drag was favorable by about the same magnitude.

  8. PULSE RADIOLYSIS IN SUPERCRITICAL RARE GAS FLUIDS

    SciTech Connect

    HOLROYD,R.

    2007-01-01

    Recently, supercritical fluids have become quite popular in chemical and semiconductor industries for applications in chemical synthesis, extraction, separation processes, and surface cleaning. These applications are based on: the high dissolving power due to density build-up around solute molecules, and the ability to tune the conditions of a supercritical fluid, such as density and temperature, that are most suitable for a particular reaction. The rare gases also possess these properties and have the added advantage of being supercritical at room temperature. Information about the density buildup around both charged and neutral species can be obtained from fundamental studies of volume changes in the reactions of charged species in supercritical fluids. Volume changes are much larger in supercritical fluids than in ordinary solvents because of their higher compressibility. Hopefully basic studies, such as discussed here, of the behavior of charged species in supercritical gases will provide information useful for the utilization of these solvents in industrial applications.

  9. [Pharmaceutical applications of supercritical carbon dioxide].

    PubMed

    Delattre, L

    2007-01-01

    The supercritical state of a fluid is intermediate between that of gases and liquids. Supercritical fluids exhibit some solvent power which is tunable in function of pressure and temperature. In the pharmaceutical field, supercritical carbon dioxide is by far the most commonly used fluid; of course, the first applications of supercritical fluids were the replacement of organic solvents in extraction processes; other applications appeared during the last twenty years: supercritical fluids are also used as eluents in chromatography, as solvents in organic synthesis or for the processing of solid dosage forms by drug micronization, by the production of nanospheres, of solid dispersions, of porous polymeric matrices containing different active substances. Supercritical carbon dioxide has been proposed for encapsulating both hydrophilic and hydrophobic drug substances into liposomes as well as for including different active substances into cyclodextrins. There are also future prospects for the use of pressurized carbon dioxide as a sterilizing agent. PMID:17299352

  10. Degludec, a new ultra-long-acting basal insulin for the treatment of diabetes mellitus type 1 and 2: advances in clinical research.

    PubMed

    Muñoz Torres, Manuel

    2014-03-01

    Degludec is the most recent molecule of the ultra-long-acting basal insulin analogues approved for human use. It forms soluble multihexamers which after subcutaneous injection are converted into monomers, and are thus slowly and continuously absorbed into the bloodstream. This absorption mechanism confers degludec an ultra-long and stable action profile, with no concentration peaks. This paper discusses the most recent studies in patients with type 1 and 2 diabetes mellitus, which showed degludec to be non inferior in decreasing HbA1c, ensuring optimum glycemic control similar to that achieved with insulin glargine or detemir. Degludec also had an improved safety profile, as it was associated to a significantly lower rate of nocturnal hypoglycemia in both types of diabetes and to a potentially lower overall hypoglycemia rate in type 2 DM. Degludec also opens the possibility to use more flexible regimens. PMID:23890782

  11. Oxo chemistry in supercritical carbon dioxide

    SciTech Connect

    Krause, T.R.; Rathke, J.W.; Klingler, R.J.

    1991-01-01

    We report an investigation of the cobalt carbonyl-catalyzed oxo process in supercritical CO{sub 2} using in situ high pressure NMR spectroscopy. The use of supercritical CO{sub 2} as the solvent medium eliminates gas-liquid mixing problems. The effect of supercritical CO{sub 2} on the oxo reaction was determined by comparing the linear to branched aldehyde yield and rate and other equilibrium processes involved in the catalytic cycle with measured values in conventional liquid solvents.

  12. Separation of biomolecules using supercritical fluid extraction.

    PubMed

    Lucien, F P; Liong, K K; Cotton, N J; Macnaughton, S J; Foster, N R

    1993-01-01

    Supercritical fluids are increasingly being used as a replacement for more conventional organic solvents in the extraction of biomolecules from a range of matrices. Supercritical fluid extraction of essential fatty acids from fish oils is discussed. Supercritical CO2 was used to fractionate two fatty acids, EPA and DHA from fish oil ethyl esters. EPA and DHA were obtained with a purity of 58% and 67% respectively from Sardine oil with an original composition of 17% and 12%. PMID:7763846

  13. Lipidomics by Supercritical Fluid Chromatography.

    PubMed

    Laboureur, Laurent; Ollero, Mario; Touboul, David

    2015-01-01

    This review enlightens the role of supercritical fluid chromatography (SFC) in the field of lipid analysis. SFC has been popular in the late 1980s and 1990s before almost disappearing due to the commercial success of liquid chromatography (LC). It is only 20 years later that a regain of interest appeared when new commercial instruments were introduced. As SFC is fully compatible with the injection of extracts in pure organic solvent, this technique is perfectly suitable for lipid analysis and can be coupled with either highly universal (UV or evaporative light scattering) or highly specific (mass spectrometry) detection methods. A short history of the use of supercritical fluids as mobile phase for the separation oflipids will be introduced first. Then, the advantages and drawbacks of SFC are discussed for each class of lipids (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterols, prenols, polyketides) defined by the LIPID MAPS consortium. PMID:26090714

  14. Lipidomics by Supercritical Fluid Chromatography

    PubMed Central

    Laboureur, Laurent; Ollero, Mario; Touboul, David

    2015-01-01

    This review enlightens the role of supercritical fluid chromatography (SFC) in the field of lipid analysis. SFC has been popular in the late 1980s and 1990s before almost disappearing due to the commercial success of liquid chromatography (LC). It is only 20 years later that a regain of interest appeared when new commercial instruments were introduced. As SFC is fully compatible with the injection of extracts in pure organic solvent, this technique is perfectly suitable for lipid analysis and can be coupled with either highly universal (UV or evaporative light scattering) or highly specific (mass spectrometry) detection methods. A short history of the use of supercritical fluids as mobile phase for the separation oflipids will be introduced first. Then, the advantages and drawbacks of SFC are discussed for each class of lipids (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterols, prenols, polyketides) defined by the LIPID MAPS consortium. PMID:26090714

  15. Supercritical Angle Fluorescence Correlation Spectroscopy

    PubMed Central

    Ries, Jonas; Ruckstuhl, Thomas; Verdes, Dorinel; Schwille, Petra

    2008-01-01

    We explore the potential of a supercritical angle (SA) objective for fluorescence correlation spectroscopy (FCS). This novel microscope objective combines tight focusing by an aspheric lens with strong axial confinement of supercritical angle fluorescence collection by a parabolic mirror lens, resulting in a small detection volume. The tiny axial extent of the detection volume features an excellent surface sensitivity, as is demonstrated by diffusion measurements in model membranes with an excess of free dye in solution. All SA-FCS measurements are directly compared to standard confocal FCS, demonstrating a clear advantage of SA-FCS, especially for diffusion measurements in membranes. We present an extensive theoretical framework that allows for accurate and quantitative evaluation of the SA-FCS correlation curves. PMID:17827221

  16. Supercritical/Solid Catalyst (SSC)

    SciTech Connect

    2010-01-01

    INL's patented, continuous-flow Supercritical/Solid Catalyst (SSC) produces the highest ASTM-quality B-100 biodiesel from waste fats, oils, and greases at the site of waste generation. SSC delivers low-cost transportation fuel, avoids significant landfill costs for municipalities, and reduces potent methane and other emissions produced in landfills from these wastes. You can learn more about INL's energy research programs at http://www.facebook.com/idahonationallaboratory.

  17. Supercritical fluid regeneration of adsorbents

    NASA Astrophysics Data System (ADS)

    Defilippi, R. P.; Robey, R. J.

    1983-05-01

    The results of a program to perform studies supercritical (fluid) carbon dioxide (SCF CO2) regeneration of adsorbents, using samples of industrial wastewaters from manufacturing pesticides and synthetic solution, and to estimate the economics of the specific wastewater treatment regenerations, based on test data are given. Processing costs for regenerating granular activated carbon GAC) for treating industrial wastewaters depend on stream properties and regeneration throughput.

  18. Recuperative supercritical carbon dioxide cycle

    SciTech Connect

    Sonwane, Chandrashekhar; Sprouse, Kenneth M; Subbaraman, Ganesan; O'Connor, George M; Johnson, Gregory A

    2014-11-18

    A power plant includes a closed loop, supercritical carbon dioxide system (CLS-CO.sub.2 system). The CLS-CO.sub.2 system includes a turbine-generator and a high temperature recuperator (HTR) that is arranged to receive expanded carbon dioxide from the turbine-generator. The HTR includes a plurality of heat exchangers that define respective heat exchange areas. At least two of the heat exchangers have different heat exchange areas.

  19. Supercritical/Solid Catalyst (SSC)

    ScienceCinema

    None

    2013-05-28

    INL's patented, continuous-flow Supercritical/Solid Catalyst (SSC) produces the highest ASTM-quality B-100 biodiesel from waste fats, oils, and greases at the site of waste generation. SSC delivers low-cost transportation fuel, avoids significant landfill costs for municipalities, and reduces potent methane and other emissions produced in landfills from these wastes. You can learn more about INL's energy research programs at http://www.facebook.com/idahonationallaboratory.

  20. Unstable supercritical discontinuous percolation transitions

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Cheng, Xueqi; Zheng, Zhiming; Chung, Ning Ning; D'Souza, Raissa M.; Nagler, Jan

    2013-10-01

    The location and nature of the percolation transition in random networks is a subject of intense interest. Recently, a series of graph evolution processes have been introduced that lead to discontinuous percolation transitions where the addition of a single edge causes the size of the largest component to exhibit a significant macroscopic jump in the thermodynamic limit. These processes can have additional exotic behaviors, such as displaying a “Devil's staircase” of discrete jumps in the supercritical regime. Here we investigate whether the location of the largest jump coincides with the percolation threshold for a range of processes, such as Erdős-Rényipercolation, percolation via edge competition and via growth by overtaking. We find that the largest jump asymptotically occurs at the percolation transition for Erdős-Rényiand other processes exhibiting global continuity, including models exhibiting an “explosive” transition. However, for percolation processes exhibiting genuine discontinuities, the behavior is substantially richer. In percolation models where the order parameter exhibits a staircase, the largest discontinuity generically does not coincide with the percolation transition. For the generalized Bohman-Frieze-Wormald model, it depends on the model parameter. Distinct parameter regimes well in the supercritical regime feature unstable discontinuous transitions—a novel and unexpected phenomenon in percolation. We thus demonstrate that seemingly and genuinely discontinuous percolation transitions can involve a rich behavior in supercriticality, a regime that has been largely ignored in percolation.

  1. Supercritical Water Mixture (SCWM) Experiment

    NASA Technical Reports Server (NTRS)

    Hicks, Michael C.; Hegde, Uday G.

    2012-01-01

    The subject presentation, entitled, Supercritical Water Mixture (SCWM) Experiment, was presented at the International Space Station (ISS) Increment 33/34 Science Symposium. This presentation provides an overview of an international collaboration between NASA and CNES to study the behavior of a dilute aqueous solution of Na2SO4 (5% w) at near-critical conditions. The Supercritical Water Mixture (SCWM) investigation, serves as important precursor work for subsequent Supercritical Water Oxidation (SCWO) experiments. The SCWM investigation will be performed in DECLICs High Temperature Insert (HTI) for the purpose of studying critical fluid phenomena at high temperatures and pressures. The HTI includes a completely sealed and integrated test cell (i.e., Sample Cell Unit SCU) that will contain approximately 0.3 ml of the aqueous test solution. During the sequence of tests, scheduled to be performed in FY13, temperatures and pressures will be elevated to critical conditions (i.e., Tc = 374C and Pc = 22 MPa) in order to observe salt precipitation, precipitate agglomeration and precipitate transport in the presence of a temperature gradient without the influences of gravitational forces. This presentation provides an overview of the motivation for this work, a description of the DECLIC HTI hardware, the proposed test sequences, and a brief discussion of the scientific research objectives.

  2. Performance and risks of advanced pulverized-coal plants

    SciTech Connect

    Nalbandian, H.

    2009-07-01

    This article is based on an in-depth report of the same title published by the IEA Clean Coal Centre, CCC/135 (see Coal Abstracts entry Sep 2008 00535). It discusses the commercial, developmental and future status of pulverized fuel power plants including subcritical supercritical and ultra supercritical systems of pulverized coal combustion, the most widely used technology in coal-fired power generation. 1 fig., 1 tab.

  3. Processing of Materials for Regenerative Medicine Using Supercritical Fluid Technology.

    PubMed

    García-González, Carlos A; Concheiro, Angel; Alvarez-Lorenzo, Carmen

    2015-07-15

    The increase in the world demand of bone and cartilage replacement therapies urges the development of advanced synthetic scaffolds for regenerative purposes, not only providing mechanical support for tissue formation, but also promoting and guiding the tissue growth. Conventional manufacturing techniques have severe restrictions for designing these upgraded scaffolds, namely, regarding the use of organic solvents, shearing forces, and high operating temperatures. In this context, the use of supercritical fluid technology has emerged as an attractive solution to design solvent-free scaffolds and ingredients for scaffolds under mild processing conditions. The state-of-the-art on the technological endeavors for scaffold production using supercritical fluids is presented in this work with a critical review on the key processing parameters as well as the main advantages and limitations of each technique. A special stress is focused on the strategies suitable for the incorporation of bioactive agents (drugs, bioactive glasses, and growth factors) and the in vitro and in vivo performance of supercritical CO2-processed scaffolds. PMID:25587916

  4. Electrodeposition of metals from supercritical fluids

    PubMed Central

    Ke, Jie; Su, Wenta; Howdle, Steven M.; George, Michael W.; Cook, David; Perdjon-Abel, Magda; Bartlett, Philip N.; Zhang, Wenjian; Cheng, Fei; Levason, William; Reid, Gillian; Hyde, Jason; Wilson, James; Smith, David C.; Mallik, Kanad; Sazio, Pier

    2009-01-01

    Electrodeposition is a widely used materials-deposition technology with a number of unique features, in particular, the efficient use of starting materials, conformal, and directed coating. The properties of the solvent medium for electrodeposition are critical to the technique's applicability. Supercritical fluids are unique solvents which give a wide range of advantages for chemistry in general, and materials processing in particular. However, a widely applicable approach to electrodeposition from supercritical fluids has not yet been developed. We present here a method that allows electrodeposition of a range of metals from supercritical carbon dioxide, using acetonitrile as a co-solvent and supercritical difluoromethane. This method is based on a careful selection of reagent and supporting electrolyte. There are no obvious barriers preventing this method being applied to deposit a range of materials from many different supercritical fluids. We present the deposition of 3-nm diameter nanowires in mesoporous silica templates using this methodology. PMID:19706479

  5. Supercritical water oxidation - Microgravity solids separation

    NASA Technical Reports Server (NTRS)

    Killilea, William R.; Hong, Glenn T.; Swallow, Kathleen C.; Thomason, Terry B.

    1988-01-01

    This paper discusses the application of supercritical water oxidation (SCWO) waste treatment and water recycling technology to the problem of waste disposal in-long term manned space missions. As inorganic constituents present in the waste are not soluble in supercritical water, they must be removed from the organic-free supercritical fluid reactor effluent. Supercritical water reactor/solids separator designs capable of removing precipitated solids from the process' supercritical fluid in zero- and low- gravity environments are developed and evaluated. Preliminary experiments are then conducted to test the concepts. Feed materials for the experiments are urine, feces, and wipes with the addition of reverse osmosis brine, the rejected portion of processed hygiene water. The solid properties and their influence on the design of several oxidation-reactor/solids-separator configurations under study are presented.

  6. EMPIRICAL METHOD TO PREDICT SOLUBILITY IN SUPERCRITICAL FLUIDS

    EPA Science Inventory

    The ability to predict the solubility of analytes in supercritical fluids is important in understanding supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC). n SFE, an analyte must dissolve in the supercritical solvent before it can be extracted. n SF...

  7. Design and application of a test rig for super-critical power transmission shafts

    NASA Technical Reports Server (NTRS)

    Darlow, M.; Smalley, A.

    1979-01-01

    The design, assembly, operational check-out and application of a test facility for testing supercritical power transmission shafts under realistic conditions of size, speed and torque are described. Alternative balancing methods and alternative damping mechanisms are demonstrated and compared. The influence of torque upon the unbalance distribution is studied, and its effect on synchronous vibrations is investigated. The feasibility of operating supercritical power transmission shafting is demonstrated, but the need for careful control, by balancing and damping, of synchronous and nonsynchronous vibrations is made clear. The facility was demonstrated to be valuable for shaft system development programs and studies for both advanced and current-production hardware.

  8. The supercritical pomeron in QCD.

    SciTech Connect

    White, A. R.

    1998-06-29

    Deep-inelastic diffractive scaling violations have provided fundamental insight into the QCD pomeron, suggesting a single gluon inner structure rather than that of a perturbative two-gluon bound state. This talk outlines a derivation of a high-energy, transverse momentum cut-off, confining solution of QCD. The pomeron, in first approximation, is a single reggeized gluon plus a ''wee parton'' component that compensates for the color and particle properties of the gluon. This solution corresponds to a super-critical phase of Reggeon Field Theory.

  9. Advanced design of ultra-thin barrier aluminum nitride/gallium nitride HEMTs; A study of device design, modeling, and analysis

    NASA Astrophysics Data System (ADS)

    Deen, David A.

    Of the III-Nitride family the AlN/GaN heterojunction has demonstrated the largest combined polarization charge and energy band offsets available in the system. Engineering the polarization fields through varying the AlN thickness leads to two-dimensional electron gas densities (2DEGs) that may be tailored between 0.5--5 x 1013 cm-2 . Furthermore, the ultra-thin (< 5 nm) barrier and excellent transport properties of this all binary heterostructure make it well suited for high electron mobility transistor applications where high frequency and high current are required. This work encompasses various design aspects of GaN-based High Electron Mobility Transistors (HEMTs) which ultimately result in the realization of several generations that utilize the AlN/GaN heterostructure. HEMTs fabricated from high-mobility, low sheet resistance heterostructures have achieved drain current densities up to 2.3 A/mm and transconductance of 480 mS/mm, which set new benchmarks for GaN-based HEMTs. Ultra-thin pre-metallization etching has been employed for the first time to reduce ohmic contact resistance for AlN/GaN HEMTs and has enabled small signal frequency performance in excess of 100 GHz. Moll's method for delay time extraction has been utilized to extract an effective electron velocity in the intrinsic region of the AlN/GaN HEMT and was found to be ˜ 1.2 x 107 cm/s. By leveraging the allowable thickness window of the AlN barrier along with the high density 2DEGs that result, several novel HEMT devices have been designed and realized. High Al-content AlxGa 1-xN back barriers have been employed for improved 2DEG confinement in several new variations of the ultra-thin AlN/GaN HEMT. A dual, parallel-channel AlN/GaN-based HEMT structure is designed and realized for the first time as an epitaxial approach to mitigating DC-RF frequency dispersion. These structures emphasize the facilitation of new device designs that are made possible through the particular qualities the Al

  10. Incorporating supercritical steam turbines into molten-salt power tower plants : feasibility and performance.

    SciTech Connect

    Pacheco, James Edward; Wolf, Thorsten; Muley, Nishant

    2013-03-01

    Sandia National Laboratories and Siemens Energy, Inc., examined 14 different subcritical and supercritical steam cycles to determine if it is feasible to configure a molten-salt supercritical steam plant that has a capacity in the range of 150 to 200 MWe. The effects of main steam pressure and temperature, final feedwater temperature, and hot salt and cold salt return temperatures were determined on gross and half-net efficiencies. The main steam pressures ranged from 120 bar-a (subcritical) to 260 bar-a (supercritical). Hot salt temperatures of 566 and 600%C2%B0C were evaluated, which resulted in main steam temperatures of 553 and 580%C2%B0C, respectively. Also, the effects of final feedwater temperature (between 260 and 320%C2%B0C) were evaluated, which impacted the cold salt return temperature. The annual energy production and levelized cost of energy (LCOE) were calculated using the System Advisory Model on 165 MWe subcritical plants (baseline and advanced) and the most promising supercritical plants. It was concluded that the supercritical steam plants produced more annual energy than the baseline subcritical steam plant for the same-size heliostat field, receiver, and thermal storage system. Two supercritical steam plants had the highest annual performance and had nearly the same LCOE. Both operated at 230 bar-a main steam pressure. One was designed for a hot salt temperature of 600%C2%B0C and the other 565%C2%B0C. The LCOEs for these plants were about 10% lower than the baseline subcritical plant operating at 120 bar-a main steam pressure and a hot salt temperature of 565%C2%B0C. Based on the results of this study, it appears economically and technically feasible to incorporate supercritical steam turbines in molten-salt power tower plants.

  11. Efficient separation of curcumin, demethoxycurcumin, and bisdemethoxycurcumin from turmeric using supercritical fluid chromatography: From analytical to preparative scale.

    PubMed

    Song, Wei; Qiao, Xue; Liang, Wen-fei; Ji, Shuai; Yang, Lu; Wang, Yuan; Xu, Yong-wei; Yang, Ying; Guo, De-an; Ye, Min

    2015-10-01

    Curcumin is the major constituent of turmeric (Curcuma longa L.). It has attracted widespread attention for its anticancer and anti-inflammatory activities. The separation of curcumin and its two close analogs, demethoxycurcumin and bisdemethoxycurcumin, has been challenging by conventional techniques. In this study, an environmentally friendly method based on supercritical fluid chromatography was established for the rapid and facile separation of the three curcuminoids directly from the methanol extract of turmeric. The method was first developed and optimized by ultra performance convergence chromatography, and was then scaled up to preparative supercritical fluid chromatography. Eluted with supercritical fluid CO2 containing 8-15% methanol (containing 10 mM oxalic acid) at a flow rate of 80 mL/min, curcumin, demethoxycurcumin and bisdemethoxycurcumin could be well separated on a Viridis BEH OBD column (Waters, 250 mm × 19 mm, 5 μm) within 6.5 min. As a result, 20.8 mg of curcumin (97.9% purity), 7.0 mg of demethoxycurcumin (91.1%), and 4.6 mg of bisdemethoxycurcumin (94.8%) were obtained after a single step of supercritical fluid chromatography separation with a mean recovery of 76.6%. Showing obvious advantages in low solvent consumption, large sample loading, and easy solvent removal, supercritical fluid chromatography was proved to be a superior technique for the efficient separation of natural products. PMID:26256681

  12. Silicide formation process in ultra-thin Ni-silicide film for advanced semiconductor devices: mechanism of NiSi2 formation at low temperature

    NASA Astrophysics Data System (ADS)

    Ikarashi, N.; Masuzaki, K.

    2011-11-01

    Atomic-resolution high-angle annular dark-field scanning-transmission electron microscopy and ab-initio calculations were used to reveal the reaction involved in the formation of ultra-thin Ni silicide film at 300°C. We found that a Ni-adamantane structure, in which Ni atoms occupy the tetrahedral interstitial voids of Si, forms at the initial stage of the reaction. We also found that the adamantane structure is under considerable compressive stress due to lattice-mismatch at the adamantane structure-Si interface (5.6%). Then, NiSi2 forms just beneath the Ni-adamantane structure at a much lower temperature than the NiSi2 formation temperature reported for the reaction between a Ni layer and Si substrate (800°C). Our analyses strongly suggest that the Ni-adamantane structure acts as a precursor in the formation of NiSi2.

  13. Mini-review: green sustainable processes using supercritical fluid carbon dioxide.

    PubMed

    Ramsey, Edward; Sun, Qiubai; Zhang, Zhiqiang; Zhang, Chongmin; Gou, Wei

    2009-01-01

    Environmentally benign carbon dioxide offers significant potential in its supercritical fluid phase to replace current reliance on a range of hazardous, relatively expensive and environmentally damaging organic solvents that are used on an extensive global basis. The unique combination of the physical properties of supercritical fluids are being exploited and further researched to continue the development and establishment of high efficiency, compact plant to provide energy and water efficient manufacturing processes. This mini-review is focused on the use and potential applications of supercritical fluid carbon dioxide for a selected range of key and emerging industrial processes as a sustainable alternative to totally eliminate or greatly reduce the requirement of numerous conventional organic solvents. Examples of the industries include: chemical extraction and purification, synthetic chemical reactions including polymerization and inorganic catalytic processes. Biochemical reactions involving enzymes, particle size engineering, textile dyeing and advanced material manufacture provide further illustrations of vital industrial activities where supercritical fluid technology processes are being implemented or developed. Some aspects relating to the economics of sustainable supercritical fluid carbon dioxide processes are also considered. PMID:19803072

  14. Unsteady aerodynamics of conventional and supercritical airfoils

    NASA Technical Reports Server (NTRS)

    Davis, S. S.; Malcolm, G. N.

    1980-01-01

    The unsteady aerodynamics of a conventional and a supercritical airfoil are compared by examining measured chordwise unsteady pressure time-histories from four selected flow conditions. Although an oscillating supercritical airfoil excites more harmonics, the strength of the airfoil's shock wave is the more important parameter governing the complexity of the unsteady flow. Whether they are conventional or supercritical, airfoils that support weak shock waves induce unsteady loads that are qualitatively predictable with classical theories; flows with strong shock waves are sensitive to details of the shock-wave and boundary-layer interaction and cannot be adequately predicted.

  15. Using supercritical fluids to refine hydrocarbons

    DOEpatents

    Yarbro, Stephen Lee

    2015-06-09

    A system and method for reactively refining hydrocarbons, such as heavy oils with API gravities of less than 20 degrees and bitumen-like hydrocarbons with viscosities greater than 1000 cp at standard temperature and pressure, using a selected fluid at supercritical conditions. A reaction portion of the system and method delivers lightweight, volatile hydrocarbons to an associated contacting unit which operates in mixed subcritical/supercritical or supercritical modes. Using thermal diffusion, multiphase contact, or a momentum generating pressure gradient, the contacting unit separates the reaction products into portions that are viable for use or sale without further conventional refining and hydro-processing techniques.

  16. Geothermal energy production with supercritical fluids

    DOEpatents

    Brown, Donald W.

    2003-12-30

    There has been invented a method for producing geothermal energy using supercritical fluids for creation of the underground reservoir, production of the geothermal energy, and for heat transport. Underground reservoirs are created by pumping a supercritical fluid such as carbon dioxide into a formation to fracture the rock. Once the reservoir is formed, the same supercritical fluid is allowed to heat up and expand, then is pumped out of the reservoir to transfer the heat to a surface power generating plant or other application.

  17. Novel Supercritical Carbon Dioxide Power Cycle Utilizing Pressured Oxy-combustion in Conjunction with Cryogenic Compression

    SciTech Connect

    Brun, Klaus; McClung, Aaron; Davis, John

    2014-03-31

    The team of Southwest Research Institute® (SwRI) and Thar Energy LLC (Thar) applied technology engineering and economic analysis to evaluate two advanced oxy-combustion power cycles, the Cryogenic Pressurized Oxy-combustion Cycle (CPOC), and the Supercritical Oxy-combustion Cycle. This assessment evaluated the performance and economic cost of the two proposed cycles with carbon capture, and included a technology gap analysis of the proposed technologies to determine the technology readiness level of the cycle and the cycle components. The results of the engineering and economic analysis and the technology gap analysis were used to identify the next steps along the technology development roadmap for the selected cycle. The project objectives, as outlined in the FOA, were 90% CO{sub 2} removal at no more than a 35% increase in cost of electricity (COE) as compared to a Supercritical Pulverized Coal Plant without CO{sub 2} capture. The supercritical oxy-combustion power cycle with 99% carbon capture achieves a COE of $121/MWe. This revised COE represents a 21% reduction in cost as compared to supercritical steam with 90% carbon capture ($137/MWe). However, this represents a 49% increase in the COE over supercritical steam without carbon capture ($80.95/MWe), exceeding the 35% target. The supercritical oxy-combustion cycle with 99% carbon capture achieved a 37.9% HHV plant efficiency (39.3% LHV plant efficiency), when coupling a supercritical oxy-combustion thermal loop to an indirect supercritical CO{sub 2} (sCO{sub 2}) power block. In this configuration, the power block achieved 48% thermal efficiency for turbine inlet conditions of 650°C and 290 atm. Power block efficiencies near 60% are feasible with higher turbine inlet temperatures, however a design tradeoff to limit firing temperature to 650°C was made in order to use austenitic stainless steels for the high temperature pressure vessels and piping and to minimize the need for advanced turbomachinery features

  18. Advances in ultra-high performance liquid chromatography coupled to tandem mass spectrometry for sensitive detection of several food allergens in complex and processed foodstuffs.

    PubMed

    Planque, M; Arnould, T; Dieu, M; Delahaut, P; Renard, P; Gillard, N

    2016-09-16

    Sensitive detection of food allergens is affected by food processing and foodstuff complexity. It is therefore a challenge to detect cross-contamination in food production that could endanger an allergic customer's life. Here we used ultra-high performance liquid chromatography coupled to tandem mass spectrometry for simultaneous detection of traces of milk (casein, whey protein), egg (yolk, white), soybean, and peanut allergens in different complex and/or heat-processed foodstuffs. The method is based on a single protocol (extraction, trypsin digestion, and purification) applicable to the different tested foodstuffs: chocolate, ice cream, tomato sauce, and processed cookies. The determined limits of quantitation, expressed in total milk, egg, peanut, or soy proteins (and not soluble proteins) per kilogram of food, are: 0.5mg/kg for milk (detection of caseins), 5mg/kg for milk (detection of whey), 2.5mg/kg for peanut, 5mg/kg for soy, 3.4mg/kg for egg (detection of egg white), and 30.8mg/kg for egg (detection of egg yolk). The main advantage is the ability of the method to detect four major food allergens simultaneously in processed and complex matrices with very high sensitivity and specificity. PMID:27554027

  19. Oxy-Combustion Environment Characterization: Fire- and Steam-Side Corrosion in Advanced Combustion

    SciTech Connect

    G. R. Holcomb; J. Tylczak; G. H. Meier; B. S. Lutz; N. M. Yanar; F. S. Pettit; J. Zhu; A. Wise; D. E. Laughlin; S. Sridhar

    2012-09-25

    Oxy-fuel combustion is burning a fuel in oxygen rather than air. The low nitrogen flue gas that results is relatively easy to capture CO{sub 2} from for reuse or sequestration. Corrosion issues associated with the environment change (replacement of much of the N{sub 2} with CO{sub 2} and higher sulfur levels) from air- to oxy-firing were examined. Alloys studied included model Fe-Cr alloys and commercial ferritic steels, austenitic steels, and nickel base superalloys. The corrosion behavior is described in terms of corrosion rates, scale morphologies, and scale/ash interactions for the different environmental conditions. Additionally, the progress towards laboratory oxidation tests in advanced ultra-supercritical steam is updated.

  20. On Blowup in Supercritical Wave Equations

    NASA Astrophysics Data System (ADS)

    Donninger, Roland; Schörkhuber, Birgit

    2016-03-01

    We study the blowup behavior for the focusing energy-supercritical semilinear wave equation in 3 space dimensions without symmetry assumptions on the data. We prove the stability in {H^2× H^1} of the ODE blowup profile.

  1. Synthesis of fluoropolymers in supercritical carbon dioxide

    SciTech Connect

    Guan, Z.; Combes, J.R.; Elsbernd, C.S.; DeSimone, J.M.

    1993-12-31

    The authors` research is focus on the synthesis of fluopolymers is supercritical carbon dioxide. The authors reported earlier the successful homogenous free radical polymerization of a series of highly fluorinated acrylic type monomers in supercritical carbon dioxide. Now it is found that a highly fluorinated styrenic polymer also exhibits very high solubility in carbon dioxide. The fluorinated styrenic polymer was synthesized in supercritical carbon dioxide using homogenous free radical polymerization and was characterized by {sup 1}HNMR, FTIR etc. Some semicrystalline fluoropolymers were also synthesized in supercritical carbon but the polymerization were heterogenous under the condition used. Various conventional nonfluorinated monomers were copolymerized with the fluorinated monomers and the copolymerizations were homogenous at very high nonfluorinated monomer feed ratio. The incorporation of nonfluorinated units onto the fluoropolymer chains increases their solubility greatly in organic solvents. The polymers synthesized in carbon dioxide will be furtherly characterized and the authors will continue the efforts on synthesizing polymers using carbon dioxide as polymerization medium.

  2. Design of supercritical swept wings

    NASA Technical Reports Server (NTRS)

    Garabedian, P.; Mcfadden, G.

    1982-01-01

    Computational fluid dynamics are used to discuss problems inherent to transonic three-dimensional flow past supercritical swept wings. The formulation for a boundary value problem for the flow past the wing is provided, including consideration of weak shock waves and the use of parabolic coordinates. A swept wing code is developed which requires a mesh of 152 x 10 x 12 points and 200 time cycles. A formula for wave drag is calculated, based on the idea that the conservation form of the momentum equation becomes an entropy inequality measuring the drag, expressible in terms of a small-disturbance equation for a potential function in two dimensions. The entropy inequality has been incorporated in a two-dimensional code for the analysis of transonic flow over airfoils. A method of artificial viscosity is explored for optimum pressure distributions with design, and involves a free boundary problem considering speed over only a portion of the wing.

  3. Supercritical fluid reverse micelle separation

    DOEpatents

    Fulton, J.L.; Smith, R.D.

    1993-11-30

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W[sub o] that determines the maximum size of the reverse micelles. The maximum ratio W[sub o] of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions. 27 figures.

  4. Supercritical fluid reverse micelle separation

    DOEpatents

    Fulton, John L.; Smith, Richard D.

    1993-01-01

    A method of separating solute material from a polar fluid in a first polar fluid phase is provided. The method comprises combining a polar fluid, a second fluid that is a gas at standard temperature and pressure and has a critical density, and a surfactant. The solute material is dissolved in the polar fluid to define the first polar fluid phase. The combined polar and second fluids, surfactant, and solute material dissolved in the polar fluid is maintained under near critical or supercritical temperature and pressure conditions such that the density of the second fluid exceeds the critical density thereof. In this way, a reverse micelle system defining a reverse micelle solvent is formed which comprises a continuous phase in the second fluid and a plurality of reverse micelles dispersed in the continuous phase. The solute material is dissolved in the polar fluid and is in chemical equilibrium with the reverse micelles. The first polar fluid phase and the continuous phase are immiscible. The reverse micelles each comprise a dynamic aggregate of surfactant molecules surrounding a core of the polar fluid. The reverse micelle solvent has a polar fluid-to-surfactant molar ratio W, which can vary over a range having a maximum ratio W.sub.o that determines the maximum size of the reverse micelles. The maximum ratio W.sub.o of the reverse micelle solvent is then varied, and the solute material from the first polar fluid phase is transported into the reverse micelles in the continuous phase at an extraction efficiency determined by the critical or supercritical conditions.

  5. Inverse Design of a Thick Supercritical Airfoil

    NASA Astrophysics Data System (ADS)

    Pambagjo, Tjoetjoek Eko; Nakahashi, Kazuhiro; Obayashi, Shigeru

    In this paper, a study on designing a thick supercritical airfoil by utilizing Takanashi’s inverse design method is discussed. One of the problems to design a thick supercritical airfoil by Takanashi’s method is that an oscillation of the geometry may occur during the iteration process. To reduce the oscillation, an airfoil parameterization method is utilized as the smoothing procedure. A guideline to determine the target pressure distribution to realize the thick airfoil is also discussed.

  6. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2003-10-31

    The objective of this project is to develop an improved ultra- lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries.

  7. An Ultra-Deep Targeted Sequencing Gene Panel Improves the Prognostic Stratification of Patients With Advanced Oral Cavity Squamous Cell Carcinoma

    PubMed Central

    Liao, Chun-Ta; Chen, Shu-Jen; Lee, Li-Yu; Hsueh, Chuen; Yang, Lan-Yan; Lin, Chien-Yu; Fan, Kang-Hsing; Wang, Hung-Ming; Ng, Shu-Hang; Lin, Chih-Hung; Tsao, Chung-Kan; Chen, I-How; Chang, Kai-Ping; Huang, Shiang-Fu; Kang, Chung-Jan; Chen, Hua-Chien; Yen, Tzu-Chen

    2016-01-01

    Abstract An improved prognostic stratification of patients with oral cavity squamous cell carcinoma (OSCC) and pathologically positive (pN+) nodes is urgently needed. Here, we sought to examine whether an ultra-deep targeted sequencing (UDT-Seq) gene panel may improve the prognostic stratification in this patient group. A mutation-based signature affecting 10 genes (including genetic mutations in 6 oncogenes and 4 tumor suppressor genes) was devised to predict disease-free survival (DFS) in 345 primary tumor specimens obtained from pN+ OSCC patients. Of the 345 patients, 144 were extracapsular spread (ECS)-negative and 201 were ECS-positive. The 5-year locoregional control, distant metastases, disease-free, disease-specific, and overall survival (OS) rates served as outcome measures. The UDT-Seq panel was an independent risk factor (RF) for 5-year locoregional control (P = 0.0067), distant metastases (P = 0.0001), DFS (P < 0.0001), disease-specific survival (DSS, P < 0.0001), and OS (P = 0.0003) in pN+ OSCC patients. The presence of ECS and pT3–4 disease were also independent RFs for DFS, DSS, and OS. A prognostic scoring system was formulated by summing up the significant covariates (UDT-Seq, ECS, pT3–4) separately for each survival endpoint. The presence of a positive UDT-Seq panel (n = 77) significantly improved risk stratification for all the survival endpoints as compared with traditional AJCC staging (P < 0.0001). Among ECS-negative patients, those with a UDT-Seq-positive panel (n = 31) had significantly worse DFS (P = 0.0005) and DSS (P = 0.0002). Among ECS-positive patients, those with a UDT-Seq-positive panel (n = 46) also had significantly worse DFS (P = 0.0032) and DSS (P = 0.0098). Our UDT-Seq gene panel consisting of clinically actionable genes was significantly associated with patient outcomes and provided better prognostic stratification than traditional AJCC staging. It was also able to predict

  8. Super Boiler: First Generation, Ultra-High Efficiency Firetube Boiler

    SciTech Connect

    2006-06-01

    This factsheet describes a research project whose goal is to develop and demonstrate a first-generation ultra-high-efficiency, ultra-low emissions, compact gas-fired package boiler (Super Boiler), and formulate a long-range RD&D plan for advanced boiler technology out to the year 2020.

  9. Near-critical and supercritical fluid extraction of polycyclic aromatic hydrocarbons from town gas soil

    SciTech Connect

    Kocher, B.S.; Azzam, F.O.; Cutright, T.J.; Lee, S.

    1995-03-01

    The contamination of soil by hazardous and toxic organic pollutants is an ever-growing problem facing the global community. One particular family of contaminants that are of major importance are polycyclic aromatic hydrocarbons (PAHs). PAHs are the result of coal gasification and high-temperature processes. Sludges from these town gas operations were generally disposed of into unlined pits and left there for eventual biodegradation. However, the high levels of PAH contained in the pits prevented the occurrence of biodegradation. PAH contaminated soil is now considered hazardous and must be cleaned to environmentally acceptable standards. One method for the remediation is extraction with supercritical water. Water in or about its critical region exhibits enhanced solvating power toward most organic compounds. Contaminated soil containing 4% by mass of hydrocarbons was ultra-cleaned in a 300-cm{sup 3} semicontinuous system to an environmentally acceptable standard of less than 200 ppm residual hydrocarbon concentration. The effects of subcritical or supercritical extraction, solvent temperature, pressure, and density have been studied, and the discerning characteristics of this type of fluid have been identified. The efficiencies of subcritical and supercritical extraction have been discussed from a process engineering standpoint.

  10. Supercriticality of charge centers in graphene probed with scanning tunneling microscopy

    NASA Astrophysics Data System (ADS)

    Jiang, Yuhang; Mao, Jinhai; Li, Guohong; Moldovan, D.; Masir, M. Ramezani; Peeters, F. M.; Andrei, Eva Y.

    2015-03-01

    The massless Dirac fermion carriers in graphene, with their effective fine structure constant,αg, being of order unity, provide fertile ground for exploring the physics of ultra-relativistic particles in the strong coupling limit.In particulara positive charge Z embedded in graphene is expected to exhibit supercritical behavior already for Z>Zc = 0.5/αg, in stark contrast to the atomic case where Zc ~ 170 is experimentally inaccessible. However due to the significant screening in graphene, attaining the supercritical regime is challenging. We will report on a new method to create charge centerswithin the graphene layer whose charge, Z, can be tuned to exceed the critical value. Using low temperature scanning tunneling microscopy and spectroscopy we study the evolution in the local electronic structure of graphene as a function of Z, from charge neutrality to the supercritical regime, which is identified by comparing to numerical simulations. Work supported by DOE-FG02-99ER45742 and NSF DMR 1207108.

  11. On the gm/ID-based approaches for threshold voltage extraction in advanced MOSFETs and their application to ultra-thin body SOI MOSFETs

    NASA Astrophysics Data System (ADS)

    Rudenko, T.; Md Arshad, M. K.; Raskin, J.-P.; Nazarov, A.; Flandre, D.; Kilchytska, V.

    2014-07-01

    In this paper, we investigate the transconductance-to-current ratio (gm/ID) methods for the threshold voltage extraction using two popular threshold voltage criteria applicable to advanced bulk and SOI MOSFETs, namely: the condition of the maximum of the second derivative of the inversion charge and of the equality of the drift and diffusion drain current components. Using analytical modeling, we derive the first-order electrical parameters matching these two physical conditions and show that in the ideal MOSFET they do not coincide. The first corresponds to the point on the gm/ID versus gate voltage (Vg) curve where d(gm/ID)/dVG exhibits a minimum and where the ratio of gm/ID to its maximum value is equal to 2/3, whereas the second is met at the point where this ratio equals 1/2. The gm/ID methods for the VTH extraction using the above two criteria and their correlation with other methods are discussed. Since our modeling is based on the unified charge control model, its predictions are expected to be valid for both bulk and SOI MOSFETs. Experimental and simulation results for advanced SOI MOSFETs are used to validate modeling derivations and clarify practical applicability and limitations of the gm/ID methods.

  12. UltraScale Computing

    NASA Astrophysics Data System (ADS)

    Maynard, , Jr.

    1997-08-01

    The Defense Advanced Research Projects Agency Information Technology Office (DARPA/ITO) supports research in technology for defense-critical applications. Defense Applications are always insatiable consumers of computing. Futuristic applications such as automated image interpretation/whole vehicle radar-cross-section/real-time prototyping/faster-than-real-time simulation will require computing capabilities orders-of-magnitude beyond the best performance that can be projected from contemporary scalable parallel processors. To reach beyond the silicon digital paradigm, DARPA has initiated a program in UltraScale Computing to explore the domain of innovative computational models, methods, and mechanisms. The objective is to encourage a complete re-thinking of computing. Novel architectures, program synthesis, and execution environments are needed as well as alternative underlying physical mechanisms including molecular, biological, optical and quantum mechanical processes. Development of these advanced computing technologies will offer spectacular performance and cost improvements beyond the threshold of traditional materials and processes. The talk will focus on novel approaches for employing vastly more computational units than shrinking transistors will enable and exploration of the biological options for solving computationally difficult problems.

  13. Advanced Concepts for Pressure-Channel Reactors: Modularity, Performance and Safety

    NASA Astrophysics Data System (ADS)

    Duffey, Romney B.; Pioro, Igor L.; Kuran, Sermet

    Based on an analysis of the development of advanced concepts for pressure-tube reactor technology, we adapt and adopt the pressure-tube reactor advantage of modularity, so that the subdivided core has the potential for optimization of the core, safety, fuel cycle and thermal performance independently, while retaining passive safety features. In addition, by adopting supercritical water-cooling, the logical developments from existing supercritical turbine technology and “steam” systems can be utilized. Supercritical and ultra-supercritical boilers and turbines have been operating for some time in coal-fired power plants. Using coolant outlet temperatures of about 625°C achieves operating plant thermal efficiencies in the order of 45-48%, using a direct turbine cycle. In addition, by using reheat channels, the plant has the potential to produce low-cost process heat, in amounts that are customer and market dependent. The use of reheat systems further increases the overall thermal efficiency to 55% and beyond. With the flexibility of a range of plant sizes suitable for both small (400 MWe) and large (1400 MWe) electric grids, and the ability for co-generation of electric power, process heat, and hydrogen, the concept is competitive. The choice of core power, reheat channel number and exit temperature are all set by customer and materials requirements. The pressure channel is a key technology that is needed to make use of supercritical water (SCW) in CANDU®1 reactors feasible. By optimizing the fuel bundle and fuel channel, convection and conduction assure heat removal using passive-moderator cooling. Potential for severe core damage can be almost eliminated, even without the necessity of activating the emergency-cooling systems. The small size of containment structure lends itself to a small footprint, impacts economics and building techniques. Design features related to Canadian concepts are discussed in this paper. The main conclusion is that development of

  14. Organic syntheses employing supercritical carbon dioxide as a reaction solvent

    NASA Technical Reports Server (NTRS)

    Barstow, Leon E. (Inventor); Ward, Glen D. (Inventor); Bier, Milan (Inventor)

    1993-01-01

    Chemical reactions are readily carried out using supercritical carbon dioxide as the reaction medium. Supercritical carbon dioxide is of special value as a reaction medium in reactions for synthesizing polypeptides, for sequencing polypeptides, or for amino acid analysis.

  15. Organic syntheses employing supercritical carbon dioxide as a reaction solvent

    NASA Technical Reports Server (NTRS)

    Barstow, Leon E. (Inventor); Ward, Glen D. (Inventor); Bier, Milan (Inventor)

    1991-01-01

    Chemical reactions are readily carried out using supercritical carbon dioxide as the reaction medium. Supercritical carbon dioxide is of special value as a reaction medium in reactions for synthesizing polypeptides, for sequencing polypeptides, or for amino acid analysis.

  16. Applications of supercritical fluid extraction and chromatography in forensic science.

    PubMed

    Radcliffe, C; Maguire, K; Lockwood, B

    2000-07-01

    Supercritical fluid technology is a rapidly expanding analytical technique. Here we give a brief insight into the background of supercritical fluid technology and how supercritical fluid extraction and supercritical fluid chromatography work in analysis. The applications of these two techniques in forensic science are known to be important. The main area of forensic use of supercritical fluid technology is in the sample preparation and separation of drugs of abuse particularly opiates, cannabinoids, cocaine and sedatives. Supercritical fluid technology can be used for both time-of-death-related drug analysis and for obtaining information relating to long term drug abuse. We also give a review of the use of supercritical fluids in two other major forensic areas, fingerprinting and the extraction and separation of explosives from both bombing events and gunshot residues. Overall we show that supercritical fluid technology is fast becoming a major part of forensic investigations and that it is an invaluable analysis technique. PMID:10869681

  17. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2001-07-18

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Issues, Task 2: Review Russian Ultra-Lightweight Cement Literature, Task 3: Test Ultra-Lightweight Cements, and Task 8: Develop Field ULHS Cement Blending and Mixing Techniques. Results reported this quarter include: preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; summary of pertinent information from Russian ultra-lightweight cement literature review; laboratory tests comparing ULHS slurries to foamed slurries and sodium silicate slurries for two different applications; and initial laboratory studies with ULHS in preparation for a field job.

  18. Supercritical waste oxidation pump investigation

    SciTech Connect

    Thurston, G.; Garcia, K.

    1993-02-01

    This report investigates the pumping techniques and pumping equipment that would be appropriate for a 5,000 gallon per day supercritical water oxidation waste disposal facility. The pumps must boost water, waste, and additives from atmospheric pressure to approximately 27.6 MPa (4,000 psia). The required flow ranges from 10 gpm to less than 0.1 gpm. For the higher flows, many commercial piston pumps are available. These pumps have packing and check-valves that will require periodic maintenance; probably at 2 to 6 month intervals. Several commercial diaphragm pumps were also discovered that could pump the higher flow rates. Diaphragm pumps have the advantage of not requiring dynamic seals. For the lower flows associated with the waste and additive materials, commercial diaphragm pumps. are available. Difficult to pump materials that are sticky, radioactive, or contain solids, could be injected with an accumulator using an inert gas as the driving mechanism. The information presented in this report serves as a spring board for trade studies and the development of equipment specifications.

  19. Pharmaceutical applications of supercritical carbon dioxide.

    PubMed

    Kaiser, C S; Römpp, H; Schmidt, P C

    2001-12-01

    The appearance of a supercritical state was already observed at the beginning of the 19th century. Nevertheless, the industrial extraction of plant and other natural materials started about twenty years ago with the decaffeination of coffee. Today carbon dioxide is the most common gas for supercritical fluid extraction in food and pharmaceutical industry. Since pure supercritical carbon dioxide is a lipophilic solvent, mixtures with organic solvents, especially alcohols, are used to increase the polarity of the extraction fluid; more polar compounds can be extracted in this way. The main fields of interest are the extraction of vegetable oils from plant material in analytical and preparative scale, the preparation of essential oils for food and cosmetic industry and the isolation of substances of pharmaceutical relevance. Progress in research was made by the precise measurement of phase equilibria data by means of different methods. Apart from extraction, supercritical fluid chromatography was introduced in the field of analytics, as well as micro- and nanoparticle formation using supercritical fluids as solvent or antisolvent. This review presents pharmaceutical relevant literature of the last twenty years with special emphasis on extraction of natural materials. PMID:11802652

  20. Supercriticality of ICME and CIR shocks

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaoyan; Smith, Edward J.

    2015-03-01

    Interplanetary coronal mass ejection (ICME) and corotating interaction region (CIR) shocks are characterized in terms of supercriticality introduced by Edmiston and Kennel (1984) to classify shocks based on whether dissipation is provided by electron resistivity alone or also requires ion viscosity. The condition for determining supercriticality is a critical Mach number, MC, a function of θBn, the angle between the upstream magnetic field, B, and the normal to the shock surface, n, and β, the ratio of the plasma and magnetic pressures. The criterion was subsequently revised by Kennel (1987) to include dissipation by electron thermal as well as electrical conductivity. Two early separate studies of ICME and CIR shocks motivated our investigation that included several improvements. We use Kennel (1987) and shocks identified by WIND near 1 AU and by Ulysses near 5 AU from the same solar cycle to provide Occurrence Probability Distributions and statistical information for all parameters. We answer three questions (1) Is the supercriticality of ICME and CIR shocks different? (2) If so, why? (3) Does the latter MC criterion change the answers? Our conclusions are (1) about two thirds of CIR shocks are supercritical as compared to one third of ICME shocks, (2) although ICME shock speeds are typically higher than CIR shocks, the fast-mode wave speeds are even higher at 1 AU than that of CIR shocks at ~5 AU causing a reduction in Mach numbers, and (3) CIR shocks are also more supercritical than ICME shocks using both criteria with slight differences.

  1. Characteristics of compressible flow of supercritical kerosene

    NASA Astrophysics Data System (ADS)

    Zhong, Feng-Quan; Fan, Xue-Jun; Wang, Jing; Yu, Gong; Li, Jian-Guo

    2012-02-01

    In this paper, compressible flow of aviation kerosene at supercritical conditions has been studied both numerically and experimentally. The thermophysical properties of supercritical kerosene are calculated using a 10-species surrogate based on the principle of extended corresponding states (ECS). Isentropic acceleration of supercritical kerosene to subsonic and supersonic speeds has been analyzed numerically. It has been found that the isentropic relationships of supercritical kerosene are significantly different from those of ideal gases. A two-stage fuel heating and delivery system is used to heat the kerosene up to a temperature of 820K and pressure of 5.5MPa with a maximum mass flow rate of 100 g/s. The characteristics of supercritical kerosene flows in a converging-diverging nozzle (Laval nozzle) have been studied experimentally. The results show that stable supersonic flows of kerosene could be established in the temperature range of 730 K-820K and the measurements in the wall pressure agree with the numerical calculation.

  2. Ultra-precision processes for optics manufacturing

    NASA Astrophysics Data System (ADS)

    Martin, William R.

    1991-12-01

    The Optics MODIL (Manufacturing Operations Development and Integration Laboratory) is developing advanced manufacturing technologies for fabrication of ultra precision optical components, aiming for a ten-fold improvement in precision and a shortening of the scheduled lead time. Current work focuses on diamond single point turning, ductile grinding, ion milling, and in/on process metrology.

  3. Ultra-precision processes for optics manufacturing

    NASA Technical Reports Server (NTRS)

    Martin, William R.

    1991-01-01

    The Optics MODIL (Manufacturing Operations Development and Integration Laboratory) is developing advanced manufacturing technologies for fabrication of ultra precision optical components, aiming for a ten-fold improvement in precision and a shortening of the scheduled lead time. Current work focuses on diamond single point turning, ductile grinding, ion milling, and in/on process metrology.

  4. Nested subcritical flows within supercritical systems

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Braun, M. J.; Wheeler, R. L., III; Mullen, R. L.

    1985-01-01

    In supercritical systems the design inlet and outlet pressures are maintained above the thermaodynamic critical pressure P sub C. Designers rely on this simple rule of thumb to circumvent problems associated with a subcritical pressure regime nested within the supercritical pressure system along with the uncertainties in heat transfer, fluid mechanics, and thermophysical property variations. The simple rule of thumb is adequate in many low-power designs but is inadequate for high-performance turbomachines and linear systems, where nested two-phase regions can exist. Examples for a free-jet expansion with backpressure greater than P sub C and a rotor (bearing) with ambient pressure greater than P sub C illustrate the existence of subcritical pressure regimes nested within supercritical systems.

  5. Supercritical fluid extraction in natural products analyses.

    PubMed

    Nahar, Lutfun; Sarker, Satyajit D

    2012-01-01

    Supercritical fluids (SCFs) are increasingly replacing the organic solvents, e.g., n-hexane, chloroform, dichloromethane, or methanol, that are conventionally used in industrial extraction, purification, and recrystallization operations because of regulatory and environmental pressures on hydrocarbon and ozone-depleting emissions. In natural products extraction and isolation, supercritical fluid extraction (SFE), especially employing supercritical CO(2), has become a popular choice. Sophisticated modern technologies allow precise regulation of changes in temperature and pressure, and thus manipulation of solvating property of the SCF, which helps the extraction of natural products of a wide range of polarities. This chapter deals mainly with the application of the SFE technology in the natural products extraction and isolation, and outlines various methodologies with specific examples. PMID:22367893

  6. Bioanalytical applications using supercritical fluid techniques.

    PubMed

    Ríos, Angel; Zougagh, Mohammed; de Andrés, Fernando

    2010-01-01

    The bioanalytical applications of supercritical fluid techniques, such as supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC), are of increasing interest. The main role of these techniques is in the sample preparation and separation of biologically active compounds, particularly drugs and their metabolites, as well as endogenous compounds. An insight is given into the different types of extracting fluids and modifiers, detectors, stationary phases, mobile phases and collection strategies. A critical discussion is presented on the existing state of the art concerning the applications of SFC and SFE with a specific focus on its advantages and limitations in the bioanalytical field. New developments and the possibilities for routine work in the near future are also covered. PMID:21083113

  7. Supercritical fluid mixing in Diesel Engine Applications

    NASA Astrophysics Data System (ADS)

    Bravo, Luis; Ma, Peter; Kurman, Matthew; Tess, Michael; Ihme, Matthias; Kweon, Chol-Bum

    2014-11-01

    A numerical framework for simulating supercritical fluids mixing with large density ratios is presented in the context of diesel sprays. Accurate modeling of real fluid effects on the fuel air mixture formation process is critical in characterizing engine combustion. Recent work (Dahms, 2013) has suggested that liquid fuel enters the chamber in a transcritical state and rapidly evolves to supercritical regime where the interface transitions from a distinct liquid/gas interface into a continuous turbulent mixing layer. In this work, the Peng Robinson EoS is invoked as the real fluid model due to an acceptable compromise between accuracy and computational tractability. Measurements at supercritical conditions are reported from the Constant Pressure Flow (CPF) chamber facility at the Army Research Laboratory. Mie and Schlieren optical spray diagnostics are utilized to provide time resolved liquid and vapor penetration length measurement. The quantitative comparison presented is discussed. Oak Ridge Associated Universities (ORAU).

  8. Supercritical fluid thermodynamics for coal processing

    SciTech Connect

    van Swol, F. . Dept. of Chemical Engineering); Eckert, C.A. . School of Chemical Engineering)

    1988-09-15

    The main objective of this research is to develop an equation of state that can be used to predict solubilities and tailor supercritical fluid solvents for the extraction and processing of coal. To meet this objective we have implemented a two-sided. approach. First, we expanded the database of model coal compound solubilities in higher temperature fluids, polar fluids, and fluid mixtures systems. Second, the unique solute/solute, solute/cosolvent and solute/solvent intermolecular interactions in supercritical fluid solutions were investigated using spectroscopic techniques. These results increased our understanding of the molecular phenomena that affect solubility in supercritical fluids and were significant in the development of an equation of state that accurately reflects the true molecular makeup of the solution. (VC)

  9. iTOUGH2-EOS1SC. Multiphase Reservoir Simulator for Water under Sub- and Supercritical Conditions. User's Guide

    SciTech Connect

    Magnusdottir, Lilja; Finsterle, Stefan

    2015-03-01

    Supercritical fluids exist near magmatic heat sources in geothermal reservoirs, and the high enthalpy fluid is becoming more desirable for energy production with advancing technology. In geothermal modeling, the roots of the geothermal systems are normally avoided but in order to accurately predict the thermal behavior when wells are drilled close to magmatic intrusions, it is necessary to incorporate the heat sources into the modeling scheme. Modeling supercritical conditions poses a variety of challenges due to the large gradients in fluid properties near the critical zone. This work focused on using the iTOUGH2 simulator to model the extreme temperature and pressure conditions in magmatic geothermal systems.

  10. Corrosion in Supercritical carbon Dioxide: Materials, Environmental Purity, Surface Treatments, and Flow Issues

    SciTech Connect

    Sridharan, Kumar; Anderson, Mark

    2013-12-10

    The supercritical CO{sub 2} Brayton cycle is gaining importance for power conversion in the Generation IV fast reactor system because of its high conversion efficiencies. When used in conjunction with a sodium fast reactor, the supercritical CO{sub 2} cycle offers additional safety advantages by eliminating potential sodium-water interactions that may occur in a steam cycle. In power conversion systems for Generation IV fast reactors, supercritical CO{sub 2} temperatures could be in the range of 30°C to 650°C, depending on the specific component in the system. Materials corrosion primarily at high temperatures will be an important issue. Therefore, the corrosion performance limits for materials at various temperatures must be established. The proposed research will have four objectives centered on addressing corrosion issues in a high-temperature supercritical CO{sub 2} environment: Task 1: Evaluation of corrosion performance of candidate alloys in high-purity supercritical CO{sub 2}: The following alloys will be tested: Ferritic-martensitic Steels NF616 and HCM12A, austenitic alloys Incoloy 800H and 347 stainless steel, and two advanced concept alloys, AFA (alumina forming austenitic) steel and MA754. Supercritical CO{sub 2} testing will be performed at 450°C, 550°C, and 650°C at a pressure of 20 MPa, in a test facility that is already in place at the proposing university. High purity CO{sub 2} (99.9998%) will be used for these tests. Task 2: Investigation of the effects of CO, H{sub 2}O, and O{sub 2} impurities in supercritical CO{sub 2} on corrosion: Impurities that will inevitably present in the CO{sub 2} will play a critical role in dictating the extent of corrosion and corrosion mechanisms. These effects must be understood to identify the level of CO{sub 2} chemistry control needed to maintain sufficient levels of purity to manage corrosion. The individual effects of important impurities CO, H{sub 2}O, and O{sub 2} will be investigated by adding them

  11. Solid catalyzed isoparaffin alkylation at supercritical fluid and near-supercritical fluid conditions

    DOEpatents

    Ginosar, Daniel M.; Fox, Robert V.; Kong, Peter C.

    2000-01-01

    This invention relates to an improved method for the alkylation reaction of isoparaffins with olefins over solid catalysts including contacting a mixture of an isoparaffin, an olefin and a phase-modifying material with a solid acid catalyst member under alkylation conversion conditions at either supercritical fluid, or near-supercritical fluid conditions, at a temperature and a pressure relative to the critical temperature(T.sub.c) and the critical pressure(P.sub.c) of the reaction mixture. The phase-modifying phase-modifying material is employed to promote the reaction's achievement of either a supercritical fluid state or a near-supercritical state while simultaneously allowing for decreased reaction temperature and longer catalyst life.

  12. Direct growth of highly dispersed MnCl2 · 4H2O nanostructures with different morphologies on graphene in supercritical CO2

    NASA Astrophysics Data System (ADS)

    Xu, Qin-Qin; Zhao, Xiao-Chen; Yin, Jian-Zhong; Xu, Gang

    2016-06-01

    Willow leaf-like Mn3O4 nanoplates@graphene nanocomposites were synthesized using graphene instead of graphene oxide as initial materials with the assistance of supercritical CO2. The near-zero surface tension and the gas-like viscosity of supercritical CO2 favored the intercalation and dispersion of precursors among the graphene nanosheets. In addition, MnCl2 · 4H2O ultra-small nanoparticles with diameter of 1–3 nm were supported on graphene using MnCl2 · 4H2O as precursor, supercritical CO2 as solvent and methanol as co-solvent under very moderate conditions. It was also found that the specific capacitance of the MnCl2 · 4H2O ultra-small nanoparticles@graphene with a metal loading of only 12.4% was twice that of pure graphene. In addition, the capacitance retention ratio of the MnCl2 · 4H2O ultra-small nanoparticles@graphene composite decreased by only 5.4% when the cycle number increased from 200 to 1000.

  13. Supercritical Carbon Dioxide Brayton Power Conversion Cycle Design for Optimized Battery-Type Integral Reactor System

    SciTech Connect

    Kim, Won J.; Kim, Tae W.; Sohn, Myoung S.; Suh, Kune Y.

    2006-07-01

    Supercritical carbon dioxide (SCO{sub 2}) promises a high power conversion efficiency of the recompression Brayton cycle due to its excellent compressibility reducing the compression work at the bottom of the cycle and to a higher density than helium or steam decreasing the component size. Therefore, the high SCO{sub 2} Brayton cycle efficiency as high as 45 % furnishes small sized nuclear reactors with economical benefits on the plant construction and maintenance. A 23 MWth BORIS (Battery Optimized Reactor Integral System) is being developed as a multipurpose reactor. BORIS, an integral-type optimized fast reactor with an ultra long life core, is coupled to the SCO{sub 2} Brayton cycle needing less room relative to the Rankine steam cycle because of its smaller components. The SCO{sub 2} Brayton cycle of BORIS consists of a 16 MW turbine, a 32 MW high temperature recuperator, a 14 MW low temperature recuperator, an 11 MW pre-cooler and 2 and 2.8 MW compressors. Entering six heat exchangers between primary and secondary system at 19.9 MPa and 663 K, the SCO{sub 2} leaves the heat exchangers at 19.9 MPa and 823 K. The promising secondary system efficiency of 45 % was calculated by a theoretical method in which the main parameters include pressure, temperature, heater power, the turbine's, recuperators' and compressors' efficiencies, and the flow split ratio of SCO{sub 2} going out from the low temperature recuperator. Test loop SOLOS (Shell-and-tube Overall Layout Optimization Study) is utilized to develop advanced techniques needed to adopt the shell-and-tube type heat exchanger in the secondary loop of BORIS by studying the SCO{sub 2} behavior from both thermal and hydrodynamic points of view. Concurrently, a computational fluid dynamics (CFD) code analysis is being conducted to develop an optimal analytical method of the SCO{sub 2} turbine efficiency having the parameters of flow characteristics of SCO{sub 2} passing through buckets of the turbine. These

  14. Petrophysical core characterization at supercritical geothermal conditions

    NASA Astrophysics Data System (ADS)

    Kummerow, Juliane; Raab, Siegfried

    2015-04-01

    There is a growing scientific interest in the exploitation of supercritical geothermal reservoirs to increase the efficiency of geothermal power plants. The utilisation of geothermal energy requires in any case the detailed knowledge of the reservoir. In reservoir engineering, the characterisation of the geothermal system by electrical resistivity tomography (ERT) is a common geophysical exploration and monitoring strategy. For a realistic interpretation of the field measurements it is necessary to know both, the physical properties of the rock and those of the interacting fluid at defined temperature and pressure conditions. While there have been made great effort in determine the physical and chemical properties of water above its critical point (Tcritical = 374.21° C and pcritical = 221.2 bar), the influence of fluid-rock interactions on petrophysical properties in supercritical aqueous systems is nearly unknown. At supercritical conditions the viscosity of the fluid is low, which enhances the mass transfer and diffusion-controlled chemical reactions. This may have considerable effects on the porosity and hydraulic properties of a rock. To investigate high-enthalpy fluid-rock systems, in the framework of the EU-funded project IMAGE we have built a new percolation set-up, which allows for the measurement of electrical resistivity and permeability of rock samples at controlled supercritical conditions of aqueous fluids (pore pressure = 400 bar and a temperature = 400° C). First results will be presented.

  15. Improved Supercritical-Solvent Extraction of Coal

    NASA Technical Reports Server (NTRS)

    Compton, L.

    1982-01-01

    Raw coal upgraded by supercritical-solvent extraction system that uses two materials instead of one. System achieved extraction yields of 20 to 49 weight percent. Single-solvent yields are about 25 weight percent. Experimental results show extraction yields may be timedependent. Observed decreases in weight of coal agreed well with increases in ash content of residue.

  16. Supercritical-Multiple-Solvent Extraction From Coal

    NASA Technical Reports Server (NTRS)

    Corcoran, W.; Fong, W.; Pichaichanarong, P.; Chan, P.; Lawson, D.

    1983-01-01

    Large and small molecules dissolve different constituents. Experimental apparatus used to test supercritical extraction of hydrogen rich compounds from coal in various organic solvents. In decreasing order of importance, relevant process parameters were found to be temperature, solvent type, pressure, and residence time.

  17. Chemical Reactions in Supercritical Carbon Dioxide

    NASA Astrophysics Data System (ADS)

    Wai, Chien M.; Hunt, Fred; Ji, Min; Chen, Xiaoyuan

    1998-12-01

    Utilizing supercritical fluids as environmentally benign solvents for chemical synthesis is one of the new approaches in the "greening" of chemistry. Carbon dioxide is the most widely used gas for supercritical fluid studies because of its moderate critical constants, nontoxic nature, and availability in pure form. One unique property of supercritical carbon dioxide (sc-CO2) is its high solubility for fluorinated compounds. Thus sc-CO2 can be used to replace Freons that are conventionally used as solvents for synthesis of perfluoro-polymers. Another property of sc-CO2 is its miscibility with gases such as H2. Heterogeneous reactions involving these gases may become homogeneous reactions in sc-CO2. Reactions in sc-CO2 may offer several advantages including controlling phase behavior and products, increasing speed of reactions, and obtaining specific reaction channels. This paper describes the following nine types of chemical reactions reported in the literature utilizing sc-CO2 as a solvent to illustrate the unique properties of the supercritical fluid reaction systems: (i) hydrogenation and hydroformylation, (ii) synthesis of organometallic compounds, (iii) metal chelation and extraction, (iv) preparation of inorganic nanoparticles, (v) stereo-selectivity of lipase-catalyzed reactions, (vi) asymmetric catalytic hydrogenation, (vii) polymerization, (viii) Diels-Alder reaction, and (ix) free radical reactions.

  18. Successful treatment with supercritical water oxidation

    SciTech Connect

    Jensen, R.

    1994-06-01

    Supercritical Water Oxidation (SCWO) operates in a totally enclosed system. It uses water at high temperatures and high pressure to chemically change wastes. Oily substances become soluble and complex hydrocarbons are converted into water and carbon dioxide. Research and development on SCWO is described.

  19. Supercritical Fluid Reactions for Coal Processing

    SciTech Connect

    Eckert, Charles A

    1997-07-01

    Exciting opportunities exist for the application of supercritical fluid (SCF) reactions for the pre-treatment of coal. Utilizing reactants which resemble the organic nitrogen containing components of coal, we propose to develop a method to tailor chemical reactions in supercritical fluid solvents for the specific application of coal denitrogenation. The Diels-Alder reaction of anthracene and 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) was chosen as the model system and was investigated in supercritical carbon dioxide. Kinetic data have been previously collected for pure CO2 at 40C and pressures between the critical pressure of CO2 (73.8 bar) and 216 bar. These data support the theory of local density enhancements suggested in the literature. Data taken at 50C and pressures ranging from 70 bar to 195 bar are currently reported; they do not exhibit the molecular clustering evident closer to the critical temperature. The data taken at 40C are now being used to construct mathematical forms which can model these pressure-induced kinetic changes. One promising avenue of investigation involves treating the supercritical medium as a dense gas, which allows a kinetic model based on high reference pressure fugacity coefficients to be derived.

  20. Chemical deposition methods using supercritical fluid solutions

    DOEpatents

    Sievers, Robert E.; Hansen, Brian N.

    1990-01-01

    A method for depositing a film of a desired material on a substrate comprises dissolving at least one reagent in a supercritical fluid comprising at least one solvent. Either the reagent is capable of reacting with or is a precursor of a compound capable of reacting with the solvent to form the desired product, or at least one additional reagent is included in the supercritical solution and is capable of reacting with or is a precursor of a compound capable of reacting with the first reagent or with a compound derived from the first reagent to form the desired material. The supercritical solution is expanded to produce a vapor or aerosol and a chemical reaction is induced in the vapor or aerosol so that a film of the desired material resulting from the chemical reaction is deposited on the substrate surface. In an alternate embodiment, the supercritical solution containing at least one reagent is expanded to produce a vapor or aerosol which is then mixed with a gas containing at least one additional reagent. A chemical reaction is induced in the resulting mixture so that a film of the desired material is deposited.

  1. Supercritical fluid extraction and processing of foods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consumers are aware of the processing techniques used to manufacture food and health supplements and are concerned about the impact of those processes on their health and the environment. Processes that use supercritical fluids as an alternative to solvents that are used to extract nutrients and bio...

  2. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2004-01-30

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries.

  3. Model-free adaptive control of supercritical circulating fluidized-bed boilers

    SciTech Connect

    Cheng, George Shu-Xing; Mulkey, Steven L

    2014-12-16

    A novel 3-Input-3-Output (3.times.3) Fuel-Air Ratio Model-Free Adaptive (MFA) controller is introduced, which can effectively control key process variables including Bed Temperature, Excess O2, and Furnace Negative Pressure of combustion processes of advanced boilers. A novel 7-input-7-output (7.times.7) MFA control system is also described for controlling a combined 3-Input-3-Output (3.times.3) process of Boiler-Turbine-Generator (BTG) units and a 5.times.5 CFB combustion process of advanced boilers. Those boilers include Circulating Fluidized-Bed (CFB) Boilers and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.

  4. The research and construction of the aspheric optics ultra-precision machining system

    NASA Astrophysics Data System (ADS)

    Luo, Songbao; Zhang, Jianming; Yang, Hui

    2006-02-01

    The Nanosys-300 aspheric optics ultra-precision machining system is the main research achievement of the Ninth-Fiveyear Plan period key advanced research, namely the aspheric optics ultra-precision machining and measuring technology. The ultra-precision machining system, machining technology and measuring technology are investigated in this paper. The corresponding research achievements are as follows: comprehensive design and manufacturing technology of aspheric optics ultra-precision machining system, high speed ultra-precision aerostatic air bearing work spindle system, ultra-precision fully constrained hydrostatic oil bearing slides, high speed ultra-precision aerostatic air bearing electrical grinder spindle system, open and high quality CNC system integrating technology, etc. The precision test and practical application shows that the concerned system has reached the world advanced level.

  5. Evolution of the core physics concept for the Canadian supercritical water reactor

    SciTech Connect

    Pencer, J.; Colton, A.; Wang, X.; Gaudet, M.; Hamilton, H.; Yetisir, M.

    2013-07-01

    The supercritical water cooled reactor (SCWR) is one of the advanced reactor concepts chosen by the GEN-IV International Forum (GIF) for research and development efforts. Canada's contribution is the Canadian SCWR, a heavy water moderated, pressure tube supercritical light water cooled reactor. Recent developments in the SCWR lattice and core concepts, primarily the introduction of a large central flow tube filled with coolant combined with a two-ring fuel assembly, have enabled significant improvements compared to earlier concepts. These improvements include a reduction in coolant void reactivity (CVR) by more than 10 mk, and an almost 40% increase in fuel exit burnup, which is achieved via balanced power distribution between the fuel pins in the fuel assembly. In this paper the evolution of the physics concept is reviewed, and the present lattice and core physics concepts are presented.

  6. Recovery of Minerals in Martian Soils Via Supercritical Fluid Extraction

    NASA Astrophysics Data System (ADS)

    Debelak, Kenneth A.; Roth, John A.

    2001-03-01

    We are investigating the use of supercritical fluids to extract mineral and/or carbonaceous material from Martian surface soils and its igneous crust. Two candidate supercritical fluids are carbon dioxide and water. The Martian atmosphere is composed mostly of carbon dioxide (approx. 95.3%) and could therefore provide an in-situ source of carbon dioxide. Water, although present in the Martian atmosphere at only approx. 0.03%, is also a candidate supercritical solvent. Previous work done with supercritical fluids has focused primarily on their solvating properties with organic compounds. Interestingly, the first work reported by Hannay and Hogarth at a meeting of the Royal Society of London in 1879 observed that increasing or decreasing the pressure caused several inorganic salts e.g., cobalt chloride, potassium iodide, and potassium bromide, to dissolve or precipitate in supercritical ethanol. In high-pressure boilers, silica, present in most boiler feed waters, is dissolved in supercritical steam and transported as dissolved silica to the turbine blades. As the pressure is reduced the silica precipitates onto the turbine blades eventually requiring the shutdown of the generator. In supercritical water oxidation processes for waste treatment, dissolved salts present a similar problem. The solubility of silicon dioxide (SiO2) in supercritical water is shown. The solubility curve has a shape characteristic of supercritical systems. At a high pressure (greater than 1750 atmospheres) increasing the temperature results in an increase in solubility of silica, while at low pressures, less than 400 atm., the solubility decreases as temperature increases. There are only a few studies in the literature where supercritical fluids are used in extractive metallurgy. Bolt modified the Mond process in which supercritical carbon monoxide was used to produce nickel carbonyl (Ni(CO)4). Tolley and Tester studied the solubility of titanium tetrachloride (TiCl4) in supercritical CO2

  7. Bio-oil production from biomass via supercritical fluid extraction

    NASA Astrophysics Data System (ADS)

    Durak, Halil

    2016-04-01

    Supercritical fluid extraction is used for producing bio-fuel from biomass. Supercritical fluid extraction process under supercritical conditions is the thermally disruption process of the lignocellulose or other organic materials at 250-400 °C temperature range under high pressure (4-5 MPa). Supercritical fluid extraction trials were performed in a cylindrical reactor (75 mL) in organic solvents (acetone, ethanol) under supercritical conditions with (calcium hydroxide, sodium carbonate) and without catalyst at the temperatures of 250, 275 and 300 °C. The produced liquids at 300 °C in supercritical liquefaction were analyzed and characterized by elemental, GC-MS and FT-IR. 36 and 37 different types of compounds were identified by GC-MS obtained in acetone and ethanol respectively.

  8. Investigation of Supercritical Water Phenomena for Space and Extraterrestrial Application

    NASA Technical Reports Server (NTRS)

    Hicks, Michael C.; Hegde, Uday G.; Fisher, John W.

    2012-01-01

    The cost of carrying or resupplying life support resources for long duration manned space exploration missions such as a mission to Mars is prohibitive and requires the development of suitable recycling technologies. Supercritical Water Oxidation (SCWO) has been identified as an attractive candidate for these extended missions because (i) pre-drying of wet waste streams is not required, (ii) product streams are relatively benign, microbially inert, and easily reclaimed, (iii) waste conversion is complete and relatively fast, and (iv) with proper design and operation, reactions can be self-sustaining. Initial work in this area at NASA was carried out at the Ames Research Center in the 1990 s with a focus on understanding the linkages between feed stock preparation (i.e., particle size and distribution) of cellulosic based waste streams and destruction rates under a range of operating temperatures and pressures. More recently, work in SCWO research for space and extra-terrestrial application has been performed at NASA s Glenn Research Center where various investigations, with a particular focus in the gravitational effects on the thermo-physical processes occurring in the bulk medium, have been pursued. In 2010 a collaborative NASA/CNES (the French Space Agency) experiment on the critical transition of pure water was conducted in the long duration microgravity environment on the International Space Station (ISS). A follow-on experiment, to study the precipitation of salt in sub-critical, trans-critical and supercritical water is scheduled to be conducted on the ISS in 2013. This paper provides a brief history of NASA s earlier work in SCWO, discusses the potential for application of SCWO technology in extended space and extraterrestrial missions, describes related research conducted on the ISS, and provides a list of future research activities to advance this technology in both terrestrial and extra-terrestrial applications.

  9. Supercritical water oxidation of products of human metabolism

    NASA Technical Reports Server (NTRS)

    Tester, Jefferson W.; Orge A. achelling, Richard K. ADTHOMASSON; Orge A. achelling, Richard K. ADTHOMASSON

    1986-01-01

    Although the efficient destruction of organic material was demonstrated in the supercritical water oxidation process, the reaction kinetics and mechanisms are unknown. The kinetics and mechanisms of carbon monoxide and ammonia oxidation in and reaction with supercritical water were studied experimentally. Experimental oxidation of urine and feces in a microprocessor controlled system was performed. A minaturized supercritical water oxidation process for space applications was design, including preliminary mass and energy balances, power, space and weight requirements.

  10. Correlated Particle Motion and THz Spectral Response of Supercritical Water

    NASA Astrophysics Data System (ADS)

    Śmiechowski, Maciej; Schran, Christoph; Forbert, Harald; Marx, Dominik

    2016-01-01

    Molecular dynamics simulations of supercritical water reveal distinctly different distance-dependent modulations of dipolar response and correlations in particle motion compared to ambient conditions. The strongly perturbed H-bond network of water at supercritical conditions allows for considerable translational and rotational freedom of individual molecules. These changes give rise to substantially different infrared spectra and vibrational density of states at THz frequencies for densities above and below the Widom line that separates percolating liquidlike and clustered gaslike supercritical water.

  11. Supercritical Fluid Infusion of Iron Additives in Polymeric Matrices

    NASA Technical Reports Server (NTRS)

    Nazem, Negin; Taylor, Larry T.

    1999-01-01

    The objective of this project was the experimentation to measure preparation of iron nanophases within polymeric matrices via supercritical fluid infusion of iron precursors followed by thermal reduction. Another objective was to determine if supercritical CO2 could infuse into the polymer. The experiment is described along with the materials, and the supercritical fluid infusion and cure procedures. X-ray photoelectron spectra and transmission electron micrographs were obtained. The results are summarized in charts, and tables.

  12. Solvent properties of liquid and supercritical hydrofluorocarbons

    SciTech Connect

    Abbott, A.P.; Eardley, C.A.

    1999-04-01

    The dipolarity/polarizability parameter {pi}{sup *}, introduced by Kamlet and Taft, was measured for difluoromethane (HFC 32) and pentafluoroethane (HFC 125) and compared with those previously reported for 1,1,1,2-tetrafluoroethane (HFC 134a). This was carried out as a function of temperature and pressure, to cover the liquid and supercritical states over the range 30--130 C and 40--300 bar. The change in dipolarity/polarizability with the reduced density is explained in terms of local density augmentation and a van der Waals model is used to predict the changes in solvent properties. The mean sphere approximation (MSA) model was applied to the data and found to produce an excellent fit for all of the solvents in both the liquid and supercritical states.

  13. Using supercritical fluids to refine hydrocarbons

    DOEpatents

    Yarbro, Stephen Lee

    2014-11-25

    This is a method to reactively refine hydrocarbons, such as heavy oils with API gravities of less than 20.degree. and bitumen-like hydrocarbons with viscosities greater than 1000 cp at standard temperature and pressure using a selected fluid at supercritical conditions. The reaction portion of the method delivers lighter weight, more volatile hydrocarbons to an attached contacting device that operates in mixed subcritical or supercritical modes. This separates the reaction products into portions that are viable for use or sale without further conventional refining and hydro-processing techniques. This method produces valuable products with fewer processing steps, lower costs, increased worker safety due to less processing and handling, allow greater opportunity for new oil field development and subsequent positive economic impact, reduce related carbon dioxide, and wastes typical with conventional refineries.

  14. Depolymerization of polyethylene terephthalate in supercritical methanol

    NASA Astrophysics Data System (ADS)

    Goto, Motonobu; Koyamoto, Hiroshi; Kodama, Akio; Hirose, Tsutomu; Nagaoka, Shoji

    2002-11-01

    The degradation of polyethylene terephthalate (PET) in supercritical methanol was investigated with the aim of developing a process for chemical recycling of waste plastics. A batch reactor was used at temperatures of 573-623 K under an estimated pressure of 20 MPa for a reaction time of 2-120 min. PET was decomposed to its monomers, dimethyl terephthalate and ethylene glycol, by methanolysis in supercritical methanol. The reaction products were analysed using size-exclusion chromatography, gas chromatography-mass spectrometry, and reversed-phase liquid chromatography. The molecular weight distribution of the products was obtained as a function of reaction time. The yields of monomer components of the decomposition products including by-products were measured. Continuous kinetics analysis was performed on the experimental data.

  15. Supercritical separation process for complex organic mixtures

    DOEpatents

    Chum, Helena L.; Filardo, Giuseppe

    1990-01-01

    A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70.degree. C. and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution.

  16. Supercritical separation process for complex organic mixtures

    DOEpatents

    Chum, H.L.; Filardo, G.

    1990-10-23

    A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70 C and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution. 1 fig.

  17. Asymmetric catalytic transformations in supercritical carbon dioxide

    SciTech Connect

    Feng, Shaoguang; Tumas, W.; Gross, M.F.; Burk, M.J.

    1996-12-31

    Supercritical carbon dioxide can be a useful environmentally benign solvent for a wide range of catalytic reactions. We have been exploring the utility of supercritical carbon dioxide as a reaction medium for catalytic asymmetric transformations. We will present results on the asymmetric hydrogenation of prochiral olefins, ketones, and unsaturated acids by Rh and Ru catalysts containing chiral phosphine ligands using hydrogen or hydrogen transfer agents. We have found that asymmetric catalytic hydrogenation reactions of enamide esters work as well or better in CO{sub 2} than in conventional solvents. We have been able to effect high conversions and ee`s using hydrogen transfer systems such as HCOOH/NEt{sub 3}, We will discuss temperature, pressure and solvent density effects on selectivity and reactivity. Kinetic studies will also be presented in order to understand the enhanced enantioselectivity that we observed in SC CO{sub 2}.

  18. Supercritical waste oxidation of aqueous wastes

    NASA Technical Reports Server (NTRS)

    Modell, M.

    1986-01-01

    For aqueous wastes containing 1 to 20 wt% organics, supercritical water oxidation is less costly than controlled incineration or activated carbon treatment and far more efficient than wet oxidation. Above the critical temperature (374 C) and pressure (218 atm) of water, organic materials and gases are completely miscible with water. In supercritical water oxidation, organics, air and water are brought together in a mixture at 250 atm and temperatures above 400 C. Organic oxidation is initiated spontaneously at these conditions. The heat of combustion is released within the fluid and results in a rise in temperature 600 to 650 C. Under these conditions, organics are destroyed rapidly with efficiencies in excess of 99.999%. Heteroatoms are oxidized to acids, which can be precipitated out as salts by adding a base to the feed. Examples are given for process configurations to treat aqueous wastes with 10 and 2 wt% organics.

  19. Supercritical droplet gasification experiments with forced convection

    NASA Technical Reports Server (NTRS)

    Litchford, Ron; Parigger, Chris; Jeng, San-Mou

    1992-01-01

    Preliminary results of a comprehensive experimental program are presented which offer the first direct observations of suspended n-heptane droplet gasifications in pure nitrogen with forced convection without the interference to optical probing associated with a flame. Measurements show attainment of a wet-bulb temperature until reduced pressures exceed about 1.0 under supercritical gas temperatures. Thereafter, temperature measurements indicate fully transient heat-up through the critical temperature. The surface is found to regress in a continuous manner with the measured temperature approaching the critical value at the end of the droplet lifetime under supercritical conditions with very mild level of convection. At increased level of convection for the same ambient conditions, similar sized droplets will undergo significant deformation during the gasification process until partially convected away as a dense vapor cloud as the critical temperature is approached.

  20. Supercritical Water Process for the Chemical Recycling of Waste Plastics

    NASA Astrophysics Data System (ADS)

    Goto, Motonobu

    2010-11-01

    The development of chemical recycling of waste plastics by decomposition reactions in sub- and supercritical water is reviewed. Decomposition reactions proceed rapidly and selectively using supercritical fluids compared to conventional processes. Condensation polymerization plastics such as PET, nylon, and polyurethane, are relatively easily depolymerized to their monomers in supercritical water. The monomer components are recovered in high yield. Addition polymerization plastics such as phenol resin, epoxy resin, and polyethylene, are also decomposed to monomer components with or without catalysts. Recycling process of fiber reinforced plastics has been studied. Pilot scale or commercial scale plants have been developed and are operating with sub- and supercritical fluids.

  1. Supercritical methanol for polyethylene terephthalate depolymerization: observation using simulator.

    PubMed

    Genta, Minoru; Iwaya, Tomoko; Sasaki, Mitsuru; Goto, Motonobu

    2007-01-01

    To apply PET depolymerization in supercritical methanol to commercial recycling, the benefits of supercritical methanol usage in PET depolymerization was investigated from the viewpoint of the reaction rate and energy demands. PET was depolymerized in a batch reactor at 573 K in supercritical methanol under 14.7 MPa and in vapor methanol under 0.98 MPa in our previous work. The main products of both reactions were the PET monomers of dimethyl terephthalate (DMT) and ethylene glycol (EG). The rate of PET depolymerization in supercritical methanol was faster than that of PET depolymerization in vapor methanol. This indicates supercritical fluid is beneficial in reducing reaction time without the use of a catalyst. We depicted the simple process flow of PET depolymerization in supercritical methanol and in vapor methanol, and by simulation evaluated the total heat demand of each process. In this simulation, bis-hydroxyethyl terephthalate (BHET) was used as a model component of PET. The total heat demand of PET depolymerization in supercritical methanol was 2.35 x 10(6)kJ/kmol Produced-DMT. That of PET depolymerization in vapor methanol was 2.84 x 10(6)kJ/kmol Produced-DMT. The smaller total heat demand of PET depolymerization in supercritical methanol clearly reveals the advantage of using supercritical fluid in terms of energy savings. PMID:16914302

  2. Supercritical fluids and their applications in biotechnology and related areas.

    PubMed

    Williams, John R; Clifford, Anthony A; al-Saidi, Salim H R

    2002-11-01

    This article serves as an overview, introducing the currently popular area of supercritical fluids (SFs) and their uses in biotechnology and related areas. It covers the fundamentals of supercritical science and moves on to the biotechnological and associated applications of these fluids. Subject areas covered include pure substances as supercritical fluids, the properties of supercritical fluids, organic cosolvents, solubility, and the following applications: extraction, chromatography, reactions, particle production, deposition, and the drying of biological specimens. Within each application, and where possible, the basic principles of the technique are given, as well as a description of the history, instrumentation, methodology, uses, problems encountered, and advantages over the traditional, nonsupercritical methods. PMID:12448881

  3. Supercritical convection, critical heat flux, and coking characteristics of propane

    NASA Technical Reports Server (NTRS)

    Rousar, D. C.; Gross, R. S.; Boyd, W. C.

    1984-01-01

    The heat transfer characteristics of propane at subcritical and supercritical pressure were experimentally evaluated using electrically heated Monel K-500 tubes. A design correlation for supercritical heat transfer coefficient was established using the approach previously applied to supercritical oxygen. Flow oscillations were observed and the onset of these oscillations at supercritical pressures was correlated with wall-to-bulk temperature ratio and velocity. The critical heat flux measured at subcritical pressure was correlated with the product of velocity and subcooling. Long duration tests at fixed heat flux conditions were conducted to evaluate coking on the coolant side tube wall and coking rates comparable to RP-1 were observed.

  4. Supercritical methanol for polyethylene terephthalate depolymerization: Observation using simulator

    SciTech Connect

    Genta, Minoru; Iwaya, Tomoko; Sasaki, Mitsuru; Goto, Motonobu

    2007-07-01

    To apply PET depolymerization in supercritical methanol to commercial recycling, the benefits of supercritical methanol usage in PET depolymerization was investigated from the viewpoint of the reaction rate and energy demands. PET was depolymerized in a batch reactor at 573 K in supercritical methanol under 14.7 MPa and in vapor methanol under 0.98 MPa in our previous work. The main products of both reactions were the PET monomers of dimethyl terephthalate (DMT) and ethylene glycol (EG). The rate of PET depolymerization in supercritical methanol was faster than that of PET depolymerization in vapor methanol. This indicates supercritical fluid is beneficial in reducing reaction time without the use of a catalyst. We depicted the simple process flow of PET depolymerization in supercritical methanol and in vapor methanol, and by simulation evaluated the total heat demand of each process. In this simulation, bis-hydroxyethyl terephthalate (BHET) was used as a model component of PET. The total heat demand of PET depolymerization in supercritical methanol was 2.35 x 10{sup 6} kJ/kmol Produced-DMT. That of PET depolymerization in vapor methanol was 2.84 x 10{sup 6} kJ/kmol Produced-DMT. The smaller total heat demand of PET depolymerization in supercritical methanol clearly reveals the advantage of using supercritical fluid in terms of energy savings.

  5. Supercritical water oxidation of landfill leachate

    SciTech Connect

    Wang Shuzhong; Guo Yang; Chen Chongming; Zhang Jie; Gong Yanmeng; Wang Yuzhen

    2011-09-15

    Highlights: > Thermal analysis of NH{sub 3} in supercritical water oxidation reaction. > Research on the catalytic reaction of landfill leachate by using response surface method. > Kinetic research of supercritical water oxidation of NH{sub 3} with and without MnO{sub 2} catalyst. - Abstract: In this paper, ammonia as an important ingredient in landfill leachate was mainly studied. Based on Peng-Robinson formulations and Gibbs free energy minimization method, the estimation of equilibrium composition and thermodynamic analysis for supercritical water oxidation of ammonia (SCWO) was made. As equilibrium is reached, ammonia could be totally oxidized in SCW. N{sub 2} is the main product, and the formation of NO{sub 2} and NO could be neglected. The investigation on SCWO of landfill leachate was conducted in a batch reactor at temperature of 380-500 deg. C, reaction time of 50-300 s and pressure of 25 MPa. The effect of reaction parameters such as oxidant equivalent ratio, reaction time and temperature were investigated. The results showed that COD and NH{sub 3} conversion improved as temperature, reaction time and oxygen excess increased. Compared to organics, NH{sub 3} is a refractory compound in supercritical water. The conversion of COD and NH{sub 3} were higher in the presence of MnO{sub 2} than that without catalyst. The interaction between reaction temperature and time was analyzed by using response surface method (RSM) and the results showed that its influence on the NH{sub 3} conversion was relatively insignificant in the case without catalyst. A global power-law rate expression was regressed from experimental data to estimate the reaction rate of NH{sub 3}. The activation energy with and without catalyst for NH{sub 3} oxidation were 107.07 {+-} 8.57 kJ/mol and 83.22 {+-} 15.62 kJ/mol, respectively.

  6. Coiled tubing drilling with supercritical carbon dioxide

    DOEpatents

    Kolle , Jack J.

    2002-01-01

    A method for increasing the efficiency of drilling operations by using a drilling fluid material that exists as supercritical fluid or a dense gas at temperature and pressure conditions existing at a drill site. The material can be used to reduce mechanical drilling forces, to remove cuttings, or to jet erode a substrate. In one embodiment, carbon dioxide (CO.sub.2) is used as the material for drilling within wells in the earth, where the normal temperature and pressure conditions cause CO.sub.2 to exist as a supercritical fluid. Supercritical carbon dioxide (SC--CO.sub.2) is preferably used with coiled tube (CT) drilling equipment. The very low viscosity SC--CO.sub.2 provides efficient cooling of the drill head, and efficient cuttings removal. Further, the diffusivity of SC--CO.sub.2 within the pores of petroleum formations is significantly higher than that of water, making jet erosion using SC--CO.sub.2 much more effective than water jet erosion. SC--CO.sub.2 jets can be used to assist mechanical drilling, for erosion drilling, or for scale removal. A choke manifold at the well head or mud cap drilling equipment can be used to control the pressure within the borehole, to ensure that the temperature and pressure conditions necessary for CO.sub.2 to exist as either a supercritical fluid or a dense gas occur at the drill site. Spent CO.sub.2 can be vented to the atmosphere, collected for reuse, or directed into the formation to aid in the recovery of petroleum.

  7. Transport and relaxation processes in supercritical fluids

    NASA Astrophysics Data System (ADS)

    Jonas, J.

    1985-11-01

    Preparations for the study of naphthalene diffusion dissolved in the supercritical fluids carbon dioxide and ethylene have proceeded as follows. We plan to use the fixed field gradient NMR technique to monitor the diffusion of the dissolved naphthalene. However, the technique is not feasible in systems with spin-spin coupling among the nuclei of interest; unfortunately the protons on naphthalene exhibit this coupling. We thus intend to use totally deuterated naphthalene and monitor the deuterium signal, a nucleus whose coupling is negligible. We therefore have designed and built a new high pressure NMR probe for the measurement of deuterium. This probe is similar to the one used in the previous naphthalene solubility study, and accommodates the same supercritical sample cells. The probe is machined from Vespel SP-1 (a high temperature plastic), and houses a 17-1/2 turn solenoid NMR coil along with thermocouples located slightly above and below the sample area. The probe has been successfully tested to 2 kbar gas pressure. The data acquisition system for the NMR spectrometer used for supercritical fluid studies has been developed and described in this report.

  8. Electron transfer in supercritical carbon dioxide: ultraexothermic charge recombination at the end of the "inverted region".

    PubMed

    Serpa, Carlos; Gomes, Paulo J S; Arnaut, Luis G; Formosinho, Sebastião J; Pina, João; de Melo, J Seixas

    2006-06-23

    Charge-recombination rates in contact radical-ion pairs, formed between aromatic hydrocarbons and nitriles in supercritical CO(2) and heptane, decrease with the exothermicity of the reactions until they reach -70 kcal mol(-1), but from there on an increase is observed. The first decrease in rate is typical of the "inverted region" of electron-transfer reactions. The change to an increase in the rate for ultra-exothermic electron transfer indicates a new free-energy relationship. We show that the resulting "double-inverted region" is not due to a change in mechanism. It is an intrinsic property of electron-transfer reactions, and it is due to the increase of the reorganisation energy with the reaction exothermicity. PMID:16548016

  9. Single-step synthesis of well-crystallized and pure barium titanate nanoparticles in supercritical fluids

    NASA Astrophysics Data System (ADS)

    Reverón, Helen; Aymonier, Cyril; Loppinet-Serani, Anne; Elissalde, Catherine; Maglione, Mario; Cansell, François

    2005-08-01

    Single-step synthesis of ultra-fine barium titanate powder with a crystallinity as high as 90% and without barium carbonate contamination has been successfully performed under supercritical conditions using a continuous-flow reactor in the temperature range 150-380 °C at 16 MPa. To synthesize this bimetallic oxide, alkoxides, ethanol and water were used. The influence of the synthesis parameters on the BaTiO3 powder characteristics was investigated. The results show that the water to alkoxide precursor ratio, the reactor temperature and the Ba:Ti molar ratio of alkoxide precursor play a major role in the crystallization of pure and well-crystallized BaTiO3 nanoparticles. The continuous mode of operation without post-treatments for powder washing, drying or crystallization increase the industrial interest.

  10. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2003-01-31

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. DOE joined the Materials Management Service (MMS)-sponsored joint industry project ''Long-Term Integrity of Deepwater Cement under Stress/Compaction Conditions.'' Results of the project contained in two progress reports are also presented in this report.

  11. Supercritical CO2 Extraction of Porogen Phase: An Alternative Route to Nanoporous Dielectrics

    SciTech Connect

    Lubguban, J.

    2004-11-04

    We present a supercritical CO{sub 2} (SCCO{sub 2}) process for the preparation of nanoporous organosilicate thin films for ultra low dielectric constant materials. The porous structure was generated by SCCO{sub 2} extraction of a sacrificial poly(propylene glycol) (PPG) from a nanohybrid film, where the nanoscopic domains of PPG porogen are entrapped within the crosslinked poly(methylsilsesquioxane) (PMSSQ) matrix. As a comparison, porous structures generated by both the usual thermal decomposition (at ca. 450 C) and by a SCCO{sub 2} process for 25 wt% and 55 wt% porogen loadings were evaluated. It is found that the SCCO{sub 2} process is effective in removing the porogen phase at relatively low temperatures (< 200 C) through diffusion of the supercritical fluid into the phase-separated nanohybrids and selective extraction of the porogen phase. Pore morphologies generated from the two methods are compared from representative three-dimensional (3D) images built from small angle x-ray scattering (SAXS) data.

  12. Ultra-Deepwater Production Systems

    SciTech Connect

    Ken L. Smith; Marc E. Leveque

    2005-05-31

    The report herein is a summary of the work performed on three projects to demonstrate hydrocarbon drilling and production methods applicable to deep and ultra deepwater field developments in the Gulf of Mexico and other like applications around the world. This work advances technology that could lead to more economic development and exploitation of reserves in ultra-deep water or remote areas. The first project is Subsea Processing. Its scope includes a review of the ''state of the art'' in subsea components to enable primary production process functions such as first stage liquids and gas separation, flow boosting, chemical treatment, flow metering, etc. These components are then combined to allow for the elimination of costly surface production facilities at the well site. A number of studies were then performed on proposed field development projects to validate the economic potential of this technology. The second project involved the design and testing of a light weight production riser made of composite material. The proposed design was to meet an actual Gulf of Mexico deepwater development project. The various engineering and testing work is reviewed, including test results. The third project described in this report encompasses the development and testing of a close tolerance liner drilling system, a new technology aimed at reducing deepwater drilling costs. The design and prototype testing in a test well are described in detail.

  13. Process parameters and morphology in puerarin, phospholipids and their complex microparticles generation by supercritical antisolvent precipitation.

    PubMed

    Li, Ying; Yang, Da-Jian; Chen, Shi-Lin; Chen, Si-Bao; Chan, Albert Sun-Chi

    2008-07-01

    The aim of the study was to develop and evaluate a new method for the production of puerarin phospholipids complex (PPC) microparticles. The advanced particle formation method, solution enhanced dispersion by supercritical fluids (SEDS), was used for the preparation of puerarin (Pur), phospholipids (PC) and their complex particles for the first time. Evaluation of the processing variables on PPC particle characteristics was also conducted. The processing variables included temperature, pressure, solution concentration, the flow rate of supercritical carbon dioxide (SC-CO2) and the relative flow rate of drug solution to CO2. The morphology, particle size and size distribution of the particles were determined. Meanwhile Pur and phospholipids were separately prepared by gas antisolvent precipitation (GAS) method and solid characterization of particles by the two supercritical methods was also compared. Pur formed by GAS was more orderly, purer crystal, whereas amorphous Pur particles between 0.5 and 1microm were formed by SEDS. The complex was successfully obtained by SEDS exhibiting amorphous, partially agglomerated spheres comprised of particles sized only about 1microm. SEDS method may be useful for the processing of other pharmaceutical preparations besides phospholipids complex particles. Furthermore adopting a GAS process to recrystallize pharmaceuticals will provide a highly versatile methodology to generate new polymorphs of drugs in addition to conventional techniques. PMID:18440736

  14. Hemispheric ultra-wideband antenna.

    SciTech Connect

    Brocato, Robert Wesley

    2006-04-01

    This report begins with a review of reduced size ultra-wideband (UWB) antennas and the peculiar problems that arise when building a UWB antenna. It then gives a description of a new type of UWB antenna that resolves these problems. This antenna, dubbed the hemispheric conical antenna, is similar to a conventional conical antenna in that it uses the same inverted conical conductor over a ground plane, but it also uses a hemispheric dielectric fill in between the conductive cone and the ground plane. The dielectric material creates a fundamentally new antenna which is reduced in size and much more rugged than a standard UWB conical antenna. The creation of finite-difference time domain (FDTD) software tools in spherical coordinates, as described in SAND2004-6577, enabled this technological advance.

  15. Surface Studies of HSLA Steel after Electrochemical Corrosion in Supercritical CO2-H2O Environment

    SciTech Connect

    Ziomek-Moroz, M. Holcomb, G. Tylczak, J Beck, J Fedkin, M. Lvov, S.

    2011-10-01

    In aqueous phase saturated with CO2, X-65 sample underwent general corrosion with formation of FeCO3. In supercritical CO2 containing water phase, two major regions are present on the sample surface after the EIS experiment. One region covered with corrosion products identified as FeCO3 and the other containing Fe, oxygen, and carbon-rich islands embedded in metal matrix identified as {alpha}-Fe. Precipitation of FeCO3 from Fe2+ and CO3 2- is responsible for formation of passive layer in oxygen-deficient, CO2 rich aqueous environment. Mechanisms of corrosion degradation occurring in supercritical CO2 as a function. Transport of supercritical CO{sub 2} is a critical element for carbon capture from fossil fuel power plants and underground sequestration. Although acceptable levels of water in supercritical CO{sub 2} (up to {approx} 5 x 10{sup -4}g/dm{sup 3}) have been established, their effects on the corrosion resistance of pipeline steels are not fully known. Moreover, the presence of SO{sub 2}, O{sub 2} impurities in addition to the water can make the fluid more corrosive and, therefore, more detrimental to service materials. Also, in this case, limited data are available on materials performance of carbon steels. to advance this knowledge, other service alloys are being investigated in the high pressure high temperature cell containing impure CO{sub 2} fluids using reliable non-destructive in-situ electrochemical methods. The electrochemical results are being augmented by a number of surface analyses of the corroded surfaces.

  16. Supercritical carbon dioxide cleaning market assessment and commercialization/deployment plan

    SciTech Connect

    Snowden-Swan, L.J.

    1994-08-01

    Through the US Department of Energy`s Industrial Waste Program (IWP), work is being conducted to research, develop, and commercialize supercritical fluid cleaning for its potential as a safer technology in a wide range of industrial cleaning operations. Commercialization, which has not proceeded as quickly as expected, is being aided by the Joint Association for the Advancement of Supercritical Technology (JAAST), a research consortium made up of industry, university, and National Laboratory partners. Under the IWP, JAAST is facilitating interaction and communication among those involved in the technology and addressing specific issues slowing its growth and acceptance. As part of the IWP/JAAST effort, Pacific Northwest Laboratory conducted a study to (1) identify and evaluate potential markets for supercritical fluids cleaning, (2) identify and address current perceptions that inhibit the acceptance of the technology into industrial cleaning operations, and (3) develop a plan that will lead to successful deployment and implementation in potential market areas. The approach to gathering the information needed for formulating the plan was to interview several individuals involved in developing, using, or commercializing the technology, specifically, supercritical carbon dioxide (SCCO{sub 2}), the most commonly used fluid. Several potential markets were identified, including cleaning gyroscope and filling hardware; optical components; instrument bearings; computer disk drive components; medical devices; and fabrics, cloths, and rags. In cases where there are parts with intricate geometries, where water-based cleaning may corrode parts and materials, or where significant time and energy for drying is required, SCCO{sub 2} may be an especially attractive alternative. While pursuing these applications, certain barriers still need to be overcome.

  17. Advanced Thermal Storage System with Novel Molten Salt: December 8, 2011 - April 30, 2013

    SciTech Connect

    Jonemann, M.

    2013-05-01

    Final technical progress report of Halotechnics Subcontract No. NEU-2-11979-01. Halotechnics has demonstrated an advanced thermal energy storage system with a novel molten salt operating at 700 degrees C. The molten salt and storage system will enable the use of advanced power cycles such as supercritical steam and supercritical carbon dioxide in next generation CSP plants. The salt consists of low cost, earth abundant materials.

  18. Supercritical-Fluid Extraction of Oil From Tar Sands

    NASA Technical Reports Server (NTRS)

    Compton, L. E.

    1982-01-01

    New supercritical solvent mixtures have been laboratory-tested for extraction of oil from tar sands. Mixture is circulated through sand at high pressure and at a temperature above critical point, dissolving organic matter into the compressed gas. Extract is recovered from sand residues. Low-temperature super-critical solvents reduce energy consumption and waste-disposal problems.

  19. NASA supercritical airfoils: A matrix of family-related airfoils

    NASA Technical Reports Server (NTRS)

    Harris, Charles D.

    1990-01-01

    The NASA supercritical airfoil development program is summarized in a chronological fashion. Some of the airfoil design guidelines are discussed, and coordinates of a matrix of family related supercritical airfoils ranging from thicknesses of 2 to 18 percent and over a design lift coefficient range from 0 to 1.0 are presented.

  20. Heat transfer to a supercritical hydrocarbon fuel with endothermic reaction.

    SciTech Connect

    Yu, W.; France, D. M.; Wambsganss, M. W.; Energy Technology; Univ. of Illinois at Chicago

    2000-01-01

    Supercritical fuel reforming is being studied as a technology for reducing emissions of industrial gas turbine engines. In this study, experiments were performed in a 2.67-mm-inside-diameter stainless steel tube with a heated length of 0.610 m for the purpose of investigating the characteristics of supercritical heat transfer with endothermic fuel reforming. Thermocouples were positioned along the tube both in the fluid stream and on the heated wall for local heat transfer measurements. Both heat transfer coefficients and endotherms were calculated from the measured results. State-of-the-art correlations for heat transfer were evaluated, and a correlation for supercritical heat transfer to hydrocarbon fuel has been developed. The results provide a basis for supercritical fuel heat-exchanger/reactor design and its practical applications, in an area that has received relatively little attention in the engineering literature, viz., supercritical forced convection heat transfer with endothermic chemical reaction.

  1. Supercritical Water Oxidation Data Acquisition Testing

    SciTech Connect

    K. M. Garcia

    1996-08-01

    Supercritical Water Oxidation (SCWO) is a high pressure oxidation process that blends air, water, and organic waste material in an oxidizer in which where the temperature and pressure in the oxidizer are maintained above the critical point of water. Supercritical water mixed with hydrocarbons, which would be insoluble at subcritical conditions, forms a homogeneous phase which possesses properties associated with both a gas and a liquid. Hydrocarbons in contact with oxygen and SCW are readily oxidized. These properties of SCW make it an attractive means for the destruction of waste streams containing organic materials. SCWO technology holds great promise for treating mixed wastes in an environmentally safe and efficient manner. In the spring of 1994 the U.S. Department of Energy (DOE) initiated a Supercritical Water Oxidation Data Acquisition Testing (SCWODAT) program. The SCWODAT program provided further information and operational data on the effectiveness of treating both simulated mixed waste and typical Navy hazardous waste using the SCWO technology. The program concentrated on the acquisition of data through pilot plant testing. The Phase I DOE testing used a simulated waste stream that contained a complex machine cutting oil and metals, that acted as surrogates for radionuclides. The Phase II Navy testing included pilot testing using hazardous waste materials to demonstrate the effectiveness of the SCWO technology. The SCWODAT program demonstrated that the SCWO process oxidized the simulated waste stream containing complex machine cutting oil, selected by DOE as representative of one of the most difficult of the organic waste streams for which SCWO had been applied. The simulated waste stream with surrogate metals in solution was oxidized, with a high destruction efficiency, on the order of 99.97%, in both the neutralized and unneutralized modes of operation.

  2. Supercritical fluid extraction of N-nitrosamines

    SciTech Connect

    Tewani, S.

    1993-01-01

    The detailed chemistry of N-nitrosamines including the mechanism of carcinogenicity, modes of formation, inhibition and destruction are discussed in detail. The occurrence and risk assessment of human exposure of these suspect cancer agents is described. The methods of isolation and analysis of N-nitrosamines are critically discussed with emphasis on Gas Chromatography (GC)-Electrochemical Detectors, GC-High Resolution Mass Spectrometry (GC-HRMS), GC-Thermal Energy Analyser (GC-TEA). The theoretical concepts of supercritical fluid extraction (SFE) are discussed. A comparison of physical and chemical properties of supercritical fluids (SF) with other phases is given. A comparison of static, dynamic, recirculating SFEs shows the versatility of this technique. The advantages over conventional methods such as Soxhlet extraction are discussed. The instrumentation and operational technique of a laboratory built supercritical fluid extractor is explained. A brief review of applications (industrial and analytical) of SFE is given. The evaluation of SFE for analytical sample preparation and analyses of volatile N-nitrosamines (VNAs), tobacco specific N-nitrosamines (TSNAs), and N-nitrosodiethanolamine (NDELA) from spiked matrices, tobacco and cutting fluids is presented. Experimental parameters such as pressure, temperature, equilibration time, collector materials, modifier are evaluated to optimize the recoveries. The extracts are analysed by GC-TEA which is already proven to be highly selective and sensitive to quantitation of N-nitrosamines. The extraction of VNAs in pure SF-CO[sub 2] is quantitative at moderate pressures and low temperatures. For the extraction of TSNAs and NDELA, it is imperative to have high pressures and presence of an additive ([approximately]10% methanol) to achieve satisfactory results. This study offers a simple, rapid, accurate and environmentally advantageous sample preparation technique for the estimation of N-nitrosamines at nanogram levels.

  3. Solute partial molal volumes in supercritical fluids

    SciTech Connect

    Eckert, C.A.; Ziger, D.H.; Johnston, K.P.; Kim, S.

    1986-06-05

    A novel technique is described for the measurement of the partial molal volume at infinite dilution of solutes in supercritical fluids. Results are reported for five systems from 2/sup 0/C above the solvent critical temperature up to 15/sup 0/C above, at pressures from just above the critical pressure to 350 bars. The solute partial molal volumes are small and positive at high pressures, but very large and negative in the highly compressible near-critical region. The results are interpreted in terms of solvent structure and intermolecular forces.

  4. Supercritical water oxidation technology for DWPF

    SciTech Connect

    Carter, J.T.; Gentilucci, J.A.

    1992-02-07

    At the request of Mr. H.L. Brandt and others in the Savannah River Field Office High Level Waste Division office, DWPF, and SRL personnel have reviewed two potential applications for supercritical water oxidation technology in DWPF. The first application would replace the current hydrolysis process by destroying the organic fractions of the precipitated cesium / potassium tetraphenylborate slurry. The second application pertains to liquid benzene destruction. After a thorough evaluation the first application is not recommended. The second is ready to be tested if needed.

  5. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2002-07-30

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, a comparison study of the three cement systems examined the effect that cement drillout has on the three cement systems. Testing to determine the effect of pressure cycling on the shear bond properties of the cement systems was also conducted. This report discusses testing that was performed to analyze the alkali-silica reactivity of ULHS in cement slurries.

  6. Creep Strength of Dissimilar Welded Joints Using High B-9Cr Steel for Advanced USC Boiler

    NASA Astrophysics Data System (ADS)

    Tabuchi, Masaaki; Hongo, Hiromichi; Abe, Fujio

    2014-10-01

    The commercialization of a 973 K (700 °C) class pulverized coal power system, advanced ultra-supercritical (A-USC) pressure power generation, is the target of an ongoing research project initiated in Japan in 2008. In the A-USC boiler, Ni or Ni-Fe base alloys are used for high-temperature parts at 923 K to 973 K (650 °C to 700 °C), and advanced high-Cr ferritic steels are planned to be used at temperatures lower than 923 K (650 °C). In the dissimilar welds between Ni base alloys and high-Cr ferritic steels, Type IV failure in the heat-affected zone (HAZ) is a concern. Thus, the high B-9Cr steel developed at the National Institute for Materials Science, which has improved creep strength in weldments, is a candidate material for the Japanese A-USC boiler. In the present study, creep tests were conducted on the dissimilar welded joints between Ni base alloys and high B-9Cr steels. Microstructures and creep damage in the dissimilar welded joints were investigated. In the HAZ of the high B-9Cr steels, fine-grained microstructures were not formed and the grain size of the base metal was retained. Consequently, the creep rupture life of the dissimilar welded joints using high B-9Cr steel was 5 to 10 times longer than that of the conventional 9Cr steel welded joints at 923 K (650 °C).

  7. Modeling new coal projects: supercritical or subcritical?

    SciTech Connect

    Carrino, A.J.; Jones, R.B.

    2006-11-15

    Decisions made on new build coal-fired plants are driven by several factors - emissions, fuel logistics and electric transmission access all provide constraints. The crucial economic decision whether to build supercritical or subcritical units often depends on assumptions concerning the reliability/availability of each technology, the cost of on-fuel operations including maintenance, the generation efficiencies and the potential for emissions credits at some future value. Modeling the influence of these key factors requires analysis and documentation to assure the assets actually meet the projected financial performance. This article addresses some of the issue related to the trade-offs that have the potential to be driven by the supercritical/subcritical decision. Solomon Associates has been collecting cost, generation and reliability data on coal-fired power generation assets for approximately 10 years using a strict methodology and taxonomy to categorize and compare actual plant operations data. This database provides validated information not only on performance, but also on alternative performance scenarios, which can provide useful insights in the pro forma financial analysis and models of new plants. 1 ref., 1 fig., 3 tabs.

  8. Ion mobility spectrometry after supercritical fluid chromatography

    SciTech Connect

    Morrissey, M.A.

    1988-01-01

    In this work, a Fourier transform ion mobility spectrometer (FT-IMS) was constructed and evaluated as a detector for supercritical fluid chromatography (SFC). The FT-IMS provides both quantitative and qualitative data of a wide range of compounds, selective and nonselective modes of chromatographic detection, and it is compatible with a wide range of SFC mobile phases. Drift spectra are presented for a number of samples, including polymers, lipids, herbicides, antibiotics, and pharmaceuticals. The unique properties of supercritical fluids made it possible to introduce these compounds into the spectrometer. While the drift spectra presented are generally simple, showing only a quasi-molecular ion, a few are surprising complex. Examples of selective and non-selective detection demonstrate the usefulness of the detector. Examples are presented for fish oil concentrate, bacon grease extract, soil extract, and polymer mixtures. In the case of Triton X-100, a non-ionic surfactant, the FT-IMS was able to selectively detect individual oligomers in the polymer mixture. In the case of a polydimethylsilicone mixture the detector isolated a contaminant in the mixture.

  9. Photothermal deflection in a supercritical fluid

    NASA Astrophysics Data System (ADS)

    Briggs, Matthew E.; Gammon, Robert W.

    1994-11-01

    The total losses due to absorption and scatter from the best optical coatings can be made as low as supercritical fluid, instead of an ordinary (non-critical) fluid, as the sensing fluid in a collinear photothermal-deflection apparatus. The noise floor in our surface-absorption measurements using supercritical xenon, Tc equals 16.7 degree(s)C, corresponds to an absorptance A equals Pabsorbed/Pincident equals 10-10 under illumination of 1 W. Bulk absorption measurements are similarly enhanced: the noise floor corresponds to an absorption coefficient of (alpha) equals 10-13 cm-1 for 1 W of illumination in a sample of length 1 cm. These levels are three orders of magnitude more sensitive than any previously reported. The enhancement is brought about by the divergence in the coefficient of thermal expansion of a fluid near the critical point. In attempting to use this sensitivity to measure the absorption in transmission of low-absorbing (

  10. Neutron scattering study of dilute supercritical solutions

    SciTech Connect

    Cochran, H.D.; Wignall, G.D.; Shah, V.M.; Londono, J.D.; Bienkowski, P.R.

    1994-10-01

    Dilute solutions in supercritical solvents exhibit interesting microstructures that are related to their dramatic macroscopic behavior. In typical attractive solutions, solutes are believed to be surrounded by clusters of solvent molecules, and solute molecules are believed to congregate in the vicinity of one another. Repulsive solutions, on the other hand, exhibit a local region of reduced solvent density around the solute with solute-solute congregation. Such microstructures influence solubility, partial molar volume, reaction kinetics, and many other properties. We have undertaken to observe these interesting microstructures directly by neutron scattering experiments on dilute noble gas systems including Ar. The three partial structure factors for such systems and the corresponding pair correlation functions can be determined by using the isotope substitution technique. The systems studied are uniquely suited for our objectives because of the large coherent neutron scattering length of the isotope {sup 36}Ar and because of the accurate potential energy functions that are available for use in molecular simulations and theoretical calculations to be compared with the scattering results. We will describe our experiment, the unique apparatus we have built for it, and the neutron scattering results from our initial allocations of beam time. We will also describe planned scattering experiments to follow those with noble gases, including study of long-chain molecules in supercritical solvents. Such studies will involve hydrocarbon mixtures with and without deuteration to provide contrast.

  11. Toward Better Modeling of Supercritical Turbulent Mixing

    NASA Technical Reports Server (NTRS)

    Selle, Laurent; Okongo'o, Nora; Bellan, Josette; Harstad, Kenneth

    2008-01-01

    study was done as part of an effort to develop computational models representing turbulent mixing under thermodynamic supercritical (here, high pressure) conditions. The question was whether the large-eddy simulation (LES) approach, developed previously for atmospheric-pressure compressible-perfect-gas and incompressible flows, can be extended to real-gas non-ideal (including supercritical) fluid mixtures. [In LES, the governing equations are approximated such that the flow field is spatially filtered and subgrid-scale (SGS) phenomena are represented by models.] The study included analyses of results from direct numerical simulation (DNS) of several such mixing layers based on the Navier-Stokes, total-energy, and conservation- of-chemical-species governing equations. Comparison of LES and DNS results revealed the need to augment the atmospheric- pressure LES equations with additional SGS momentum and energy terms. These new terms are the direct result of high-density-gradient-magnitude regions found in the DNS and observed experimentally under fully turbulent flow conditions. A model has been derived for the new term in the momentum equation and was found to perform well at small filter size but to deteriorate with increasing filter size. Several alternative models were derived for the new SGS term in the energy equation that would need further investigations to determine if they are too computationally intensive in LES.

  12. Modern supercritical fluid technology for food applications.

    PubMed

    King, Jerry W

    2014-01-01

    This review provides an update on the use of supercritical fluid (SCF) technology as applied to food-based materials. It advocates the use of the solubility parameter theory (SPT) for rationalizing the results obtained when employing sub- and supercritical media to food and nutrient-bearing materials and for optimizing processing conditions. Total extraction and fractionation of foodstuffs employing SCFs are compared and are illustrated by using multiple fluids and unit processes to obtain the desired food product. Some of the additional prophylactic benefits of using carbon dioxide as the processing fluid are explained and illustrated with multiple examples of commercial products produced using SCF media. I emphasize the role of SCF technology in the context of environmentally benign and sustainable processing, as well as its integration into an overall biorefinery concept. Conclusions are drawn in terms of current trends in the field and future research that is needed to secure new applications of the SCF platform as applied in food science and technology. PMID:24328430

  13. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2001-10-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). Work reported herein addresses tasks performed in the fourth quarter as well as the other three quarters of the past year. The subjects that were covered in previous reports and that are also discussed in this report include: Analysis of field laboratory data of active cement applications from three oil-well service companies; Preliminary findings from a literature review focusing on problems associated with ultra-lightweight cements; Summary of pertinent information from Russian ultra-lightweight cement literature review; and Comparison of compressive strengths of ULHS systems using ultrasonic and crush methods Results reported from the fourth quarter include laboratory testing of ULHS systems along with other lightweight cement systems--foamed and sodium silicate slurries. These comparison studies were completed for two different densities (10.0 and 11.5 lb/gal) and three different field application scenarios. Additional testing included the mechanical properties of ULHS systems and other lightweight systems. Studies were also performed to examine the effect that circulation by centrifugal pump during mixing has on breakage of ULHS.

  14. NASA F-8A Crusader Supercritical Wing Aircraft

    NASA Technical Reports Server (NTRS)

    1973-01-01

    A Vought F-8A Crusader was selected by NASA as the testbed aircraft (designated TF-8A) to install an experimental Supercritical Wing in place of the conventional wing. The unique design of the Supercritical Wing reduces the effect of shock waves on the upper surface near Mach 1, which in turn reduces drag. In this photograph a Vought F-8A Crusader is shown being used as a flying testbed for an experimental Supercritical Wing airfoil. The smooth fairing of the fiberglass glove with the wing is illustrated in this view.

  15. Code System for Supercritical Water Cooled Reactor LOCA Analysis.

    1999-10-13

    Version 00 The new SCRELA code was developed to analyze the LOCA of the supercritical water cooled reactor. Since the currently available LWR codes for LOCA analysis could not analyze the significant differences in reactor characteristics between the supercritical-water cooled reactor and the current LWR, the first objective of this code development was to analyze the uniqueness of this reactor. The behavior of the supercritical water in the blowdown phase and the reflood phase ismore » modeled.« less

  16. High Density Thermal Energy Storage with Supercritical Fluids

    NASA Technical Reports Server (NTRS)

    Ganapathi, Gani B.; Wirz, Richard

    2012-01-01

    A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

  17. Processing of Advanced Cast Alloys for A-USC Steam Turbine Applications

    NASA Astrophysics Data System (ADS)

    Jablonski, Paul D.; Hawk, Jeffery A.; Cowen, Christopher J.; Maziasz, Philip J.

    2012-02-01

    The high-temperature components within conventional supercritical coal-fired power plants are manufactured from ferritic/martensitic steels. To reduce greenhouse-gas emissions, the efficiency of pulverized coal steam power plants must be increased to as high a temperature and pressure as feasible. The proposed steam temperature in the DOE/NETL Advanced Ultra Supercritical power plant is high enough (760°C) that ferritic/martensitic steels will not work for the majority of high-temperature components in the turbine or for pipes and tubes in the boiler due to temperature limitations of this class of materials. Thus, Ni-based superalloys are being considered for many of these components. Off-the-shelf forged nickel alloys have shown good promise at these temperatures, but further improvements can be made through experimentation within the nominal chemistry range as well as through thermomechanical processing and subsequent heat treatment. However, cast nickel-based superalloys, which possess high strength, creep resistance, and weldability, are typically not available, particularly those with good ductility and toughness that are weldable in thick sections. To address those issues related to thick casting for turbine casings, for example, cast analogs of selected wrought nickel-based superalloys such as alloy 263, Haynes 282, and Nimonic 105 have been produced. Alloy design criteria, melt processing experiences, and heat treatment are discussed with respect to the as-processed and heat-treated microstructures and selected mechanical properties. The discussion concludes with the prospects for full-scale development of a thick section casting for a steam turbine valve chest or rotor casing.

  18. Supercritical carbon dioxide cycle control analysis.

    SciTech Connect

    Moisseytsev, A.; Sienicki, J. J.

    2011-04-11

    This report documents work carried out during FY 2008 on further investigation of control strategies for supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle energy converters. The main focus of the present work has been on investigation of the S-CO{sub 2} cycle control and behavior under conditions not covered by previous work. An important scenario which has not been previously calculated involves cycle operation for a Sodium-Cooled Fast Reactor (SFR) following a reactor scram event and the transition to the primary coolant natural circulation and decay heat removal. The Argonne National Laboratory (ANL) Plant Dynamics Code has been applied to investigate the dynamic behavior of the 96 MWe (250 MWt) Advanced Burner Test Reactor (ABTR) S-CO{sub 2} Brayton cycle following scram. The timescale for the primary sodium flowrate to coast down and the transition to natural circulation to occur was calculated with the SAS4A/SASSYS-1 computer code and found to be about 400 seconds. It is assumed that after this time, decay heat is removed by the normal ABTR shutdown heat removal system incorporating a dedicated shutdown heat removal S-CO{sub 2} pump and cooler. The ANL Plant Dynamics Code configured for the Small Secure Transportable Autonomous Reactor (SSTAR) Lead-Cooled Fast Reactor (LFR) was utilized to model the S-CO{sub 2} Brayton cycle with a decaying liquid metal coolant flow to the Pb-to-CO{sub 2} heat exchangers and temperatures reflecting the decaying core power and heat removal by the cycle. The results obtained in this manner are approximate but indicative of the cycle transient performance. The ANL Plant Dynamics Code calculations show that the S-CO{sub 2} cycle can operate for about 400 seconds following the reactor scram driven by the thermal energy stored in the reactor structures and coolant such that heat removal from the reactor exceeds the decay heat generation. Based on the results, requirements for the shutdown heat removal system may be defined

  19. Model-free adaptive control of advanced power plants

    SciTech Connect

    Cheng, George Shu-Xing; Mulkey, Steven L.; Wang, Qiang

    2015-08-18

    A novel 3-Input-3-Output (3.times.3) Model-Free Adaptive (MFA) controller with a set of artificial neural networks as part of the controller is introduced. A 3.times.3 MFA control system using the inventive 3.times.3 MFA controller is described to control key process variables including Power, Steam Throttle Pressure, and Steam Temperature of boiler-turbine-generator (BTG) units in conventional and advanced power plants. Those advanced power plants may comprise Once-Through Supercritical (OTSC) Boilers, Circulating Fluidized-Bed (CFB) Boilers, and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.

  20. Supercritical Fluid Extraction of Aflatoxin B 1 from Soil

    EPA Science Inventory

    This research describes the development of a Supercritical Fluid Extraction (SFE) method to recover aflatoxin B1 from fortified soil. The effects of temperature, pressure, modifier (identity and percentage), and extraction type were assessed. Using the optimized SFE conditions, ...

  1. Physical properties of the benchmark models program supercritical wing

    NASA Technical Reports Server (NTRS)

    Dansberry, Bryan E.; Durham, Michael H.; Bennett, Robert M.; Turnock, David L.; Silva, Walter A.; Rivera, Jose A., Jr.

    1993-01-01

    The goal of the Benchmark Models Program is to provide data useful in the development and evaluation of aeroelastic computational fluid dynamics (CFD) codes. To that end, a series of three similar wing models are being flutter tested in the Langley Transonic Dynamics Tunnel. These models are designed to simultaneously acquire model response data and unsteady surface pressure data during wing flutter conditions. The supercritical wing is the second model of this series. It is a rigid semispan model with a rectangular planform and a NASA SC(2)-0414 supercritical airfoil shape. The supercritical wing model was flutter tested on a flexible mount, called the Pitch and Plunge Apparatus, that provides a well-defined, two-degree-of-freedom dynamic system. The supercritical wing model and associated flutter test apparatus is described and experimentally determined wind-off structural dynamic characteristics of the combined rigid model and flexible mount system are included.

  2. Thermodynamic properties of supercritical carbon dioxide: Widom and Frenkel lines.

    PubMed

    Fomin, Yu D; Ryzhov, V N; Tsiok, E N; Brazhkin, V V

    2015-02-01

    Supercritical fluids are widely used in a number of important technological applications, yet the theoretical progress in the field has been rather moderate. Fairly recently, a new understanding of the liquidlike and gaslike properties of supercritical fluids has come to the fore, particularly with the advent of the Widom and Frenkel lines that aim to demarcate different physical properties on the phase diagram. Here, we report the results of a computational study of supercritical carbon dioxide, one of the most important fluids in the chemical industry. We study the response functions of CO_{2} in the supercritical state and calculate the locations of their maxima (Widom lines). We also report the preliminary calculations of the Frenkel line, the line of crossover of microscopic dynamics of particles. Our insights are relevant to physical processes in the atmosphere of Venus and its evolution. PMID:25768462

  3. Supercritical fluid carbon dioxide cleaning of plutonium parts

    SciTech Connect

    Hale, S.J.

    1991-12-31

    Supercritical fluid carbon dioxide is under investigation in this work for use as a cleaning solvent for the final cleaning of plutonium parts. These parts must be free of organic residue to avoid corrosion in the stockpile. Initial studies on stainless steel and full-scale mock-up parts indicate that the oils of interest are easily and adequately cleaned from the metal surfaces with supercritical fluid carbon dioxide. Results from compatibility studies show that undesirable oxidation or other surface reactions are not occurring during exposure of plutonium to the supercritical fluid. Cleaning studies indicate that the oils of interest are removed from the plutonium surface under relatively mild conditions. These studies indicate that supercritical fluid carbon dioxide is a very promising cleaning medium for this application.

  4. Research of a Supercritical Pressure Water Cooled Reactor in Korea

    SciTech Connect

    Bae, Yoon-Yeong; Joo, Hyung-Kook; Jang, Jinsung; Jeong, Yong-Hwan; Song, Jin-ho; Yoon, Han-Young; Yoo, Jung-Yul

    2004-07-01

    In this paper the activities on the supercritical pressure water-cooled reactor (SCWR) in Korea are briefly introduced. Four projects on a SCWR are being conducted in Korea. Three of them are supported by the I-NERI program while one is by KAERI. Two of the I-NERI-supported projects concern suitable materials for supercritical pressure and temperature, and radiation environment. The other I-NERI-supported project surveys numerically and experimentally the proper turbulence modeling for the numerical calculation of heat transfer phenomena at a supercritical condition. Heat transfer at a supercritical condition is being studied at KAERI experimentally using carbon dioxide as a coolant. The test loop is to be completed by the end of 2004. (authors)

  5. SUPERCRITICAL FLUID EXTRACTION OF PARTICULATE AND ADSORBENT MATERIALS. PART 2

    EPA Science Inventory

    The physical properties of supercritical fluids allow similar solvent strengths as liquids, but with higher diffusion coefficients, lower viscosities and an extended temperature range which provides the potential for more rapid and efficient extraction rates than possible with li...

  6. Supercritical carbon dioxide extraction of solvent from micromachined structures

    SciTech Connect

    Russick, E.M.; Adkins, C.L.J.; Dyck, C.W.

    1995-12-31

    We have demonstrated that supercritical carbon dioxide extraction can be used for solvent removal to successfully release compliant surface micromachined structures on silicon wafers developed at Sandia National Laboratories. Structures that have been successfully extracted and released include single gear microengines, bridge and cantilever beams, pressure transducers, and experimental comb drive actuators. Since the supercritical fluid has negligible surface tension, it has virtually unabated access to solvent residing in capillary-like spaces as narrow as 1--3 {mu}m under the micromachined features. While conventional drying techniques have been plagued with the collapse and sticking of micromachined structures due to surface tension effects, supercritical carbon dioxide has been shown to reproducibly dry components and test structures, including bridge and cantilever beams approaching 1000 {mu}m in length, without collapsing. The equipment and the extraction process are described, and photographs of supercritically dried test structures and components are presented.

  7. LOX droplet vaporization in a supercritical forced convective environment

    NASA Technical Reports Server (NTRS)

    Hsiao, Chia-Chun; Yang, Vigor

    1993-01-01

    Modern liquid rocket engines often use liquid oxygen (LOX) and liquid hydrogen (LH2) as propellants to achieve high performance, with the engine operational conditions in the supercritical regimes of the propellants. Once the propellant exceeds its critical state, it essentially becomes a puff of dense fluid. The entire field becomes a continuous medium, and no distinct interfacial boundary between the liquid and gas exists. Although several studies have been undertaken to investigate the supercritical droplet behavior at quiescent conditions, very little effort has been made to address the fundamental mechanisms associated with LOX droplet vaporization in a supercritical, forced convective environment. The purpose is to establish a theoretical framework within which supercritical droplet dynamics and vaporization can be studied systematically by means of an efficient and robust numerical algorithm.

  8. Corrosion Behavior of Candidate Alloys for Supercritical Water Reactors

    SciTech Connect

    Sridharan, K.; Zillmer, A.; Licht, J.R.; Allen, T.R.; Anderson, M.H.; Tan, L.

    2004-07-01

    The corrosion and stress corrosion cracking behavior of metallic cladding and other core internal structures is critical to the success of the Generation IV Supercritical Water-cooled Reactors (SCWR). The eventual materials selected will be chosen based on the combined corrosion, stress-corrosion, mechanical performance, and radiation stability properties. Among the materials being considered are austenitic stainless steels, ferritic/martensitic steels, and nickel-base alloys. This paper reports initial studies on the corrosion performance of the candidate alloys 316 austenitic stainless steel, Inconel 718, and Zircaloy-2, all exposed to supercritical water at 300-500 deg. C in a corrosion loop at the University of Wisconsin. Long-term corrosion performance of AISI 347, also a candidate austenitic steel, has also been examined by sectioning samples from a component that was exposed for a period of about 30 years in supercritical water at the Genoa 3 Supercritical Water fossil power plant located in Genoa, Wisconsin. (authors)

  9. Supercritical fluid technology: a promising approach in pharmaceutical research.

    PubMed

    Girotra, Priti; Singh, Shailendra Kumar; Nagpal, Kalpana

    2013-02-01

    Supercritical fluids possess the unique properties of behaving like liquids and gases, above their critical point. Supercritical fluid technology has recently emerged as a green and novel technique for various processes such as solubility enhancement of poorly soluble drugs, plasticization of polymers, surface modification, nanosizing and nanocrystal modification, and chromatographic extraction. Research interest in this area has been fuelled because of the numerous advantages that the technology offers over the conventional methods. This work aims to review the merits, demerits, and various processes such as rapid expansion of supercritical solutions (RESS), particles from gas saturated solutions (PGSS), gas antisolvent process (GAS), supercritical antisolvent process (SAS) and polymerization induced phase separation (PIPS), that have enabled this technology to considerably raise the interest of researchers over the past two decades. An insight has been given into the numerous applications of this technology in pharmaceutical industry and the future challenges which must be appropriately dealt with to make it effective on a commercial scale. PMID:23036159

  10. SUPERCRITICAL FLUID EXTRACTION OF PARTICULATE AND ADSORBENT MATERIALS

    EPA Science Inventory

    The report is a summary of work performed by PNL on the extraction of semivolatile organic materials (SVOCs), for example, polynuclear aromatic compounds, from various adsorbents and environmental matrices, using supercritical fluids (SCFs) as extractants. The results of the work...

  11. Dispersion of organic pigments using supercritical carbon dioxide.

    PubMed

    Cheng, W T; Hsu, C W; Chih, Y W

    2004-02-01

    This research describes dispersion of organic pigments using supercritical fluids. With low surface tension and high diffusivity of fluids in supercritical states, aggregated particles may be effectively wetted and swelled to form the primary constituent of the dispersing solution by volume. In this paper, the conditions of temperature and pressure are used to control the density of supercritical carbon dioxide subject to PGMEA as cosolvent for dispersing organic powder in a solution. As shown from measurement with a laser scattering particle analyzer, the average diameter of phthalocyanine green 36 with the haloid structure can be significantly reduced to 93.5 nm; for aminoanthraquinone red containing and amino group (-NH(2)) and phthalocyanine blue 15:6 with symmetry benzene and inner hydrogen bond, the mean particle sizes are 178.5 and 188.7 nm, respectively, using supercritical CO(2). Additionally, the transmittance of UV light is used to confirm the dispersing performance in this study. PMID:14693141

  12. Particle Formation by Supercritical Fluid Extraction and Expansion Process

    PubMed Central

    Zhou, Junbo; Li, Haiting; Quan, Can

    2013-01-01

    Supercritical fluid extraction and expansion (SFEE) patented technology combines the advantages of both supercritical fluid extraction (SFE) and rapid expansion of supercritical solution (RESS) with on-line coupling, which makes the nanoparticle formation feasible directly from matrix such as Chinese herbal medicine. Supercritical fluid extraction is a green separation technology, which has been developed for decades and widely applied in traditional Chinese medicines or natural active components. In this paper, a SFEE patented instrument was firstly built up and controlled by LABVIEW work stations. Stearic acid was used to verify the SFEE process at optimized condition; via adjusting the preexpansion pressure and temperature one can get different sizes of particles. Furthermore, stearic acid was purified during the SFEE process with HPLC-ELSD detecting device; purity of stearic acid increased by 19%, and the device can purify stearic acid. PMID:24223031

  13. Stability Analysis of a Uniformly Heated Channel with Supercritical Water

    SciTech Connect

    Ortega Gomez, T.; Class, A.; Schulenberg, T.; Lahey, R.T. Jr.

    2006-07-01

    The thermal-hydraulic stability of a uniformly heated channel at supercritical water pressure has been investigated to help understand the system instability phenomena which may occur in Supercritical Water Nuclear Reactors (SCWR). We have extended the modeling approach often used for Boiling Water Nuclear Reactor (BWR) stability analysis to supercritical pressure operation conditions. We have shown that Ledinegg excursive instabilities and pressure-drop oscillations (PDO) will not occur in supercritical water systems. The linear stability characteristics of a typical uniformly heated channel were computed by evaluating the eigenvalues of the model. An analysis of non-linear instability phenomena was also performed in the time domain and the dynamic bifurcations were evaluated. (authors)

  14. Enantioselective separation of biologically active basic compounds in ultra-performance supercritical fluid chromatography.

    PubMed

    Geryk, Radim; Kalíková, Květa; Schmid, Martin G; Tesařová, Eva

    2016-08-17

    The enantioseparation of basic compounds represent a challenging task in modern SFC. Therefore this work is focused on development and optimization of fast SFC methods suitable for enantioseparation of 27 biologically active basic compounds of various structures. The influences of the co-solvent type as well as different mobile phase additives on retention, enantioselectivity and enantioresolution were investigated. Obtained results confirmed that the mobile phase additives, especially bases (or the mixture of base and acid), improve peak shape and enhance enantioresolution. The best results were achieved with isopropylamine or the mixture of isopropylamine and trifluoroacetic acid as additives. In addition, the effect of temperature and back pressure were evaluated to optimize the enantioseparation process. The immobilized amylose-based chiral stationary phase, i.e. tris(3,5-dimethylphenylcarbamate) derivative of amylose proved to be useful tool for the enantioseparation of a broad spectrum of chiral bases. The chromatographic conditions that yielded baseline enantioseparations of all tested compounds were discovered. The presented work can serve as a guide for simplifying the method development for enantioseparation of basic racemates in SFC. PMID:27286774

  15. Boiler materials for ultra-supercritical coal power plants - steamside oxidation

    SciTech Connect

    Viswanathan, R.; Sarver, J.; Tanzosh, J.M.

    2006-06-15

    The corrosion behavior of tubing materials carrying steam at high temperature is of great concern to fossil power plant operators. This is due to the fact that the oxide films formed on the steam side can lead to major failures and consequently to reduced plant availability. The wall loss of the pressure boundary caused by oxidation can increase the hoop stresses and cause premature creep failures; second, the increased insulation of the tubes due to the low thermal conductivity of the oxide film can lead to increased metal temperature, thereby exacerbating the fireside corrosion as well as creep problems. The third concern is that thicker oxides may spall more easily when the plant is cooled down. On restart, the spalled material may lodge somewhere in the system with the potential for causing tube blockages, or it may be swept out with the working fluid and enter the steam turbine causing erosion damage to the turbine nozzles and blades. Failures of tubing and turbine components by these mechanisms have been widely reported in the United States. In view of the importance of the steamside oxidation, a major study of the phenomenon is being carried out as part of a major national program sponsored by the U.S. Department of Energy and the Ohio Coal Development Office. As a prelude to the experimental work, a literature survey was performed to document the state of the art. Results of the review are reported here.

  16. US program on materials technology for ultra-supercritical coal power plants

    SciTech Connect

    Viswanathan, R.; Henry, J.F.; Tanzosh, J.; Stanko, G.; Shingledecker, J.; Vitalis, B.; Purgert, R.

    2005-06-01

    The study reported on here is aimed at identifying, evaluating, and qualifying the materials needed for the construction of the critical components of coal-fired boilers that are capable of operating with steam at temperatures of 760{sup o}C (1400{sup o}F) and pressures of 35 MPa (5000 psi). The economic viability of such a plant has been explored. Candidate alloys applicable to various ranges of temperatures have been identified. Stress rupture tests have been completed on the base metal and on welds to a number of alloys. Steamside oxidation tests in an autoclave at 650{sup o}C (1200{sup o}F) and 800{sup o}C (1475 {sup o}F) have been completed. Fireside corrosion tests have been conducted under conditions simulating those of waterwalls and superheater/reheater tubes. The weldability and fabricability of the alloys have been investigated. The capabilities of various overlay coatings and diffusion coatings have been examined. This article provides a status report on the progress achieved to date on this project.

  17. Electromagnetic Whistler Precursors at Supercritical Interplanetary Shocks

    NASA Technical Reports Server (NTRS)

    Wilson, L. B., III

    2012-01-01

    We present observations of electromagnetic precursor waves, identified as whistler mode waves, at supercritical interplanetary shocks using the Wind search coil magnetometer. The precursors propagate obliquely with respect to the local magnetic field, shock normal vector, solar wind velocity, and they are not phase standing structures. All are right-hand polarized with respect to the magnetic field (spacecraft frame), and all but one are right-hand polarized with respect to the shock normal vector in the normal incidence frame. Particle distributions show signatures of specularly reflected gyrating ions, which may be a source of free energy for the observed modes. In one event, we simultaneously observe perpendicular ion heating and parallel electron acceleration, consistent with wave heating/acceleration due to these waves.

  18. Containment system for supercritical water oxidation reactor

    SciTech Connect

    Chastagner, P.

    1991-12-31

    This invention is comprised of a system for containment of a supercritical water oxidation reactor in the event of a rupture of the reactor. The system includes a containment for housing the reaction vessel and a communicating chamber for holding a volume of coolant, such as water. The coolant is recirculated and sprayed to entrain and cool any reactants that might have escaped from the reaction vessel. Baffles at the entrance to the chamber prevent the sprayed coolant from contacting the reaction vessel. An impact-absorbing layer is positioned between the vessel and the containment to at least partially absorb momentum of any fragments propelled by the rupturing vessel. Remote, quick-disconnecting fittings exterior to the containment, in cooperation with shut-off valves, enable the vessel to be isolated and the system safely taken off-line. Normally-closed orifices throughout the containment and chamber enable decontamination of interior surfaces when necessary.

  19. Containment system for supercritical water oxidation reactor

    DOEpatents

    Chastagner, Philippe

    1994-01-01

    A system for containment of a supercritical water oxidation reactor in the event of a rupture of the reactor. The system includes a containment for housing the reaction vessel and a communicating chamber for holding a volume of coolant, such as water. The coolant is recirculated and sprayed to entrain and cool any reactants that might have escaped from the reaction vessel. Baffles at the entrance to the chamber prevent the sprayed coolant from contacting the reaction vessel. An impact-absorbing layer is positioned between the vessel and the containment to at least partially absorb momentum of any fragments propelled by the rupturing vessel. Remote, quick-disconnecting fittings exterior to the containment, in cooperation with shut-off valves, enable the vessel to be isolated and the system safely taken off-line. Normally-closed orifices throughout the containment and chamber enable decontamination of interior surfaces when necessary.

  20. Gasification of cyanobacterial in supercritical water.

    PubMed

    Zhang, Huiwen; Zhu, Wei; Xu, Zhirong; Gong, Miao

    2014-01-01

    Cyanobacterial collected from eutrophic freshwater lakes constituted intractable waste with a rich algae biomass content. Supercritical water gasification (SCWG) was proposed to treat the cyanobacterial and to produce hydrogen for energy. The H 2 yield reached 2.92 mol/kg at reaction conditions of 500 °C, 30 min and 22 MPa; this yield accounted for 26% of the total gaseous products. Abundant ammonia and dissolved reactive phosphorous were concentrated in the liquid product, which could be recovered and used as a liquid fertilizer. Solid residue, which accounted only for about 1% of the wet weight, was mainly composed of coke and ash. The efficiency of H 2 production was better than that from other biomass, because of the abundant organic matter in cyanobacterial. Thus, cyanobacterial are an ideal biomass feedstock for H 2 production from SCWG. PMID:25176482

  1. NMR study of compressed supercritical water

    NASA Astrophysics Data System (ADS)

    Lamb, W. J.; Jonas, J.

    1981-01-01

    The proton spin-lattice relaxation time T1 in water has been measured as a function of pressure in the temperature range 150 to 700°C. This study focuses on the supercritical region (tc=374°C) where the spin-rotation interaction mechanism dominates the observed proton relaxation rate. Since water is an asymmetric top molecule, the analysis of the experimental data involves a number of simplifying assumptions discussed in detail. The experimental finding that in supercritical water the spin-rotation relaxation time T 1SR is a linear function of density ρ, up to relatively high densities (ρ≃ 1.5 ρc) provides rationale for analysis of the NMR experimental data in terms of a model used for dilute gases. The T 1SR data are analyzed on the basis of the assumption that the collision modulated spin-rotation interactions can be described by a single correlation function which is an exponential function of time. Using this procedure, we find that T 1SR/ρ αT-2, i.e.T 1SR/ρ exhibits a stronger temperature dependence than that found (T 1SR/ρ αT-3/2) for many polar and nonpolar gases. The calculated effective cross sections for the transfer of angular momentum σeff which show strong temperature dependence (σeff αT-1.5) are several times larger than the kinetic cross sections. By assuming applicability of expressions derived for isotropic reorientation of spherical-top molecules and using the effective spin-rotation interaction constant as obtained from microwave measurements, we are able to calculate the angular momentum correlation time τJ, over the range of temperatures and densities studied. In the supercritical region τJ⩾τΘ, where τΘ is the reorientational correlation time, and the estimated mean angle of reorientation ΔΘ¯ is in the range 50° to 800°. The T 1SR data are also interpreted in terms of the modified rough hard sphere (RHS) model which for ρ<2ρc takes into account the effect of attractive forces. We find that 1/T 1SR is a linear

  2. Assessment of supercritical fluids for drug analysis.

    PubMed

    Messer, D C; Taylor, L T; Moore, W N; Weiser, W E

    1993-12-01

    Supercritical fluid (SF) CO2 is receiving a great deal of interest in the scientific and engineering community as a replacement for toxic organic solvents. Analytical chemists employ large quantities of organic solvents during preparation of the sample for analysis. The application of SF extraction with CO2 and modified CO2 to the isolation of active drug components and metabolites from various pharmaceutical and biological matrices is reviewed. Studies are described that deal with spiked drugs in animal feed, residual solvent in drug formulations, and active ingredients in over-the-counter products. The experimental challenges to implementing this technology for trace analysis are discussed. While much of the impetus for working with SFs is prompted by regulatory issues, it would appear that SFs afford the analyst a better-cheaper-faster-safer way of performing drug analysis. PMID:8122298

  3. Containment system for supercritical water oxidation reactor

    DOEpatents

    Chastagner, P.

    1994-07-05

    A system is described for containment of a supercritical water oxidation reactor in the event of a rupture of the reactor. The system includes a containment for housing the reaction vessel and a communicating chamber for holding a volume of coolant, such as water. The coolant is recirculated and sprayed to entrain and cool any reactants that might have escaped from the reaction vessel. Baffles at the entrance to the chamber prevent the sprayed coolant from contacting the reaction vessel. An impact-absorbing layer is positioned between the vessel and the containment to at least partially absorb momentum of any fragments propelled by the rupturing vessel. Remote, quick-disconnecting fittings exterior to the containment, in cooperation with shut-off valves, enable the vessel to be isolated and the system safely taken off-line. Normally-closed orifices throughout the containment and chamber enable decontamination of interior surfaces when necessary. 2 figures.

  4. Ceramic powder synthesis in supercritical fluids

    SciTech Connect

    Adkins, C.L.J.; Russick, E.M.; Cesarano, J; Tadros, M.E.; Voigt, J.A.

    1996-04-01

    Gas-phase processing plays an important role in the commercial production of a number of ceramic powders. These include titanium dioxide, carbon black, zinc oxide, and silicon dioxide. The total annual output of these materials is on the order of 2 million tons. The physical processes involved in gas-phase synthesis are typical of those involved in solution -phase synthesis: chemical reaction kinetics, mass transfer, nucleation, coagulation, and condensation. This report focuses on the work done under a Laboratory-Directed Research and Development (LDRD) project that explored the use of various high pressure techniques for ceramic powder synthesis. Under this project, two approaches were taken. First, a continuous flow, high pressure water reactor was built and studied for powder synthesis. And second, a supercritical carbon dioxide static reactor, which was used in conjunction with surfactants, was built and used to generate oxide powders.

  5. Thermally and Acoustically Driven Transport in Supercritical Fluids

    NASA Astrophysics Data System (ADS)

    Hasan, Nusair Mohammed Ibn

    Supercritical fluids are fluids at temperature and pressure above their respective critical values. Such fluids are increasingly being used in power generation, refrigeration and chemical process industry. The objectives of the current research were to develop a fundamental understanding of the transport phenomena in near-critical supercritical fluids via high-resolution numerical simulations and careful experiments for improved design of industrial processes and applications that employ supercritical fluids. A set of synergistic experimental and numerical studies were proposed in this research. Four main focus areas under the broad spectrum of supercritical fluid transport were chosen -- (a) characterization of thermoacoustic transport, (b) interaction of thermoacoustic transport with natural convection, (c) characterization of acoustically augmented transport and (d) enhancement of mass transport using acoustic waves. A numerical model to simulate thermoacoustic convection in near-critical fluids was developed. In the computational model, the conservation equations were solved along with a real-fluid equation of state for supercritical fluid and variable thermo-physical properties. Thermoacoustic waves in near-critical carbon dioxide were also investigated experimentally on acoustic time scales using a fast response measurement system. The predicted results from the calculation and the measurements provide interesting details regarding the thermal transport mechanisms at near-critical states. The numerical model was applied to investigate the interaction of buoyancy driven flows with thermoacoustic convection in near-critical supercritical fluids. This model can be extensively used for studying the steady-state thermal transport and stability behavior of near-critical fluids. Mechanically driven acoustic waves in supercritical fluid generated by a vibrating wall in a cylindrical resonator were studied both numerically and experimentally. The simulations revealed

  6. Phase transitions in supercritical explosive percolation

    NASA Astrophysics Data System (ADS)

    Chen, Wei; Nagler, Jan; Cheng, Xueqi; Jin, Xiaolong; Shen, Huawei; Zheng, Zhiming; D'Souza, Raissa M.

    2013-05-01

    Percolation describes the sudden emergence of large-scale connectivity as edges are added to a lattice or random network. In the Bohman-Frieze-Wormald model (BFW) of percolation, edges sampled from a random graph are considered individually and either added to the graph or rejected provided that the fraction of accepted edges is never smaller than a decreasing function with asymptotic value of α, a constant. The BFW process has been studied as a model system for investigating the underlying mechanisms leading to discontinuous phase transitions in percolation. Here we focus on the regime α∈[0.6,0.95] where it is known that only one giant component, denoted C1, initially appears at the discontinuous phase transition. We show that at some point in the supercritical regime C1 stops growing and eventually a second giant component, denoted C2, emerges in a continuous percolation transition. The delay between the emergence of C1 and C2 and their asymptotic sizes both depend on the value of α and we establish by several techniques that there exists a bifurcation point αc=0.763±0.002. For α∈[0.6,αc), C1 stops growing the instant it emerges and the delay between the emergence of C1 and C2 decreases with increasing α. For α∈(αc,0.95], in contrast, C1 continues growing into the supercritical regime and the delay between the emergence of C1 and C2 increases with increasing α. As we show, αc marks the minimal delay possible between the emergence of C1 and C2 (i.e., the smallest edge density for which C2 can exist). We also establish many features of the continuous percolation of C2 including scaling exponents and relations.

  7. Supercritical Wing Technology: A Progress Report on Flight Evaluations

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The papers in this compilation were presented at the NASA Symposium on "Supercritical Wing Technology: A Progress Report on Flight Evaluation" held at the NASA Flight Research Center, Edwards, Calif., on February 29, 1972. The purpose of the symposium was to present timely information on flight results obtained with the F-8 and T-2C supercritical wing configurations, discuss comparisons with wind-tunnel predictions, and project [ ] flight programs planned for the F-8 and F-III (TACT) airplanes.

  8. Fischer-Tropsch synthesis in supercritical fluids. Final report

    SciTech Connect

    Akgerman, A.; Bukur, D.B.

    1998-12-31

    The objective of this study was to investigate Fischer-Tropsch Synthesis (FTS) in the supercritical phase employing a commercial precipitated iron catalysts. As the supercritical fluid the authors used propane and n-hexane. The catalyst had a nominal composition of 100 Fe/5 Cu/4.2 K/25 SiO{sub 2} on mass basis and was used in a fixed bed reactor under both normal (conventional) and supercritical conditions. Experimental data were obtained at different temperatures (235 C, 250 C, and 260 C) and synthesis gas feed compositions (H{sub 2}/CO molar feed ratio of 0.67, 1.0 and 2.0) in both modes of operation under steady state conditions. The authors compared the performance of the precipitated iron catalyst in the supercritical phase, with the data obtained in gas phase (fixed bed reactor) and slurry phase (STS reactor). Comparisons were made in terms of bulk catalyst activity and various aspects of product selectivity (e.g. lumped hydrocarbon distribution and olefin content as a function of carbon number). In order to gain better understanding of the role of intraparticle mass transfer during FTS under conventional or supercritical conditions, the authors have measured diffusivities of representative hydrocarbon products in supercritical fluids, as well as their effective diffusion rates into the pores of catalyst at the reaction conditions. They constructed a Taylor dispersion apparatus to measure diffusion coefficients of hydrocarbon products of FTS in sub and supercritical ethane, propane, and hexane. In addition, they developed a tracer response technique to measure the effective diffusivities in the catalyst pores at the same conditions. Based on these results they have developed an equation for prediction of diffusion in supercritical fluids, which is based on the rough hard sphere theory.

  9. Supercritical carbon dioxide: putting the fizz into biomaterials

    PubMed Central

    Barry, John J.A.; Silva, Marta M.C.G.; Popov, Vladimir K.; Shakesheff, Kevin M.; Howdle, Steven M.

    2005-01-01

    This paper describes recent progress made in the use of high pressure or supercritical fluids to process polymers into three-dimensional tissue engineering scaffolds. Three current examples are highlighted: foaming of acrylates for use in cartilage tissue engineering; plasticization and encapsulation of bioactive species into biodegradable polyesters for bone tissue engineering; and a novel laser sintering process used to fabricate three-dimensional biodegradable polyester structures from particles prepared via a supercritical route. PMID:17464360

  10. Process for treating effluent from a supercritical water oxidation reactor

    DOEpatents

    Barnes, Charles M.; Shapiro, Carolyn

    1997-01-01

    A method for treating a gaseous effluent from a supercritical water oxidation reactor containing entrained solids is provided comprising the steps of expanding the gas/solids effluent from a first to a second lower pressure at a temperature at which no liquid condenses; separating the solids from the gas effluent; neutralizing the effluent to remove any acid gases; condensing the effluent; and retaining the purified effluent to the supercritical water oxidation reactor.

  11. Process for treating effluent from a supercritical water oxidation reactor

    DOEpatents

    Barnes, C.M.; Shapiro, C.

    1997-11-25

    A method for treating a gaseous effluent from a supercritical water oxidation reactor containing entrained solids is provided comprising the steps of expanding the gas/solids effluent from a first to a second lower pressure at a temperature at which no liquid condenses; separating the solids from the gas effluent; neutralizing the effluent to remove any acid gases; condensing the effluent; and retaining the purified effluent to the supercritical water oxidation reactor. 6 figs.

  12. Enhanced coal liquefaction by pyrolysis in supercritical fluids

    SciTech Connect

    Paulaitis, M.E.; Klein, M.T.; Sandler, S.I.

    1990-11-19

    A fundamental investigation of a novel coal liquefaction process was undertaken which combines pyrolysis and supercritical-fluid solvent extraction. The experimental work consisted of determining: (1) coal pyrolysis reaction pathways, kinetics and mechanisms; (2) equilibrium solubilities of coal-related compounds in supercritical water. Experiments involving model coal compounds (tetralin and 1-methylnaphthalene, phenethyl phenyl ether, 1,3-diphenylpropane, benzyl phenyl ether, benzylamine). 8 refs., 6 figs., 9 tabs.

  13. Design Construction and Operation of a Supercritical Carbon Dioxide (sCO2) Loop for Investigation of Dry Cooling and Natural Circulation Potential for Use in Advanced Small Modular Reactors Utilizing sCO2 Power Conversion Cycles.

    SciTech Connect

    Middleton, Bobby D.; Rodriguez, Salvador B.; Carlson, Matthew David

    2015-11-01

    This report outlines the work completed for a Laboratory Directed Research and Development project at Sandia National Laboratories from October 2012 through September 2015. An experimental supercritical carbon dioxide (sCO 2 ) loop was designed, built, and o perated. The experimental work demonstrated that sCO 2 can be uti lized as the working fluid in an air - cooled, natural circulation configuration to transfer heat from a source to the ultimate heat sink, which is the surrounding ambient environment in most ca ses. The loop was also operated in an induction - heated, water - cooled configuration that allows for measurements of physical parameters that are difficult to isolate in the air - cooled configuration. Analysis included the development of two computational flu id dynamics models. Future work is anticipated to answer questions that were not covered in this project.

  14. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2002-01-23

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems: foamed and sodium silicate slurries. Comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, water permeability, and shear bond. Testing was also done to determine the effect that temperature cycling has on the shear bond properties of the cement systems. In addition, analysis was carried out to examine alkali silica reactivity of slurries containing ULHS. Data is also presented from a study investigating the effects of mixing and pump circulation on breakage of ULHS. Information is also presented about the field application of ULHS in cementing a 7-in. intermediate casing in south Texas.

  15. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2002-04-29

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, comparison studies of the three cement systems examined several properties: tensile strength, Young's modulus, and shear bond. Testing to determine the effect of temperature cycling on the shear bond properties of the cement systems was also conducted. In addition, the stress-strain behavior of the cement types was studied. This report discusses a software program that is being developed to help design ULHS cements and foamed cements.

  16. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2002-10-31

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report includes results from laboratory testing of ULHS systems along with other lightweight cement systems, including foamed and sodium silicate slurries. During this project quarter, a comparison study of the three cement systems examined the effect that cement drillout has on the three cement systems. Testing to determine the effect of pressure cycling on the shear bond properties of the cement systems was also conducted. This report discusses testing that will be performed for analyzing the alkali-silica reactivity of ULHS in cement slurries, as well as the results of Field Tests 1 and 2.

  17. A Supercritical CO{sub 2} Gas Turbine Power Cycle for Next-Generation Nuclear Reactors

    SciTech Connect

    Dostal, Vaclav; Driscoll, Michael J.; Hejzlar, Pavel; Todreas, Neil E.

    2002-07-01

    Although proposed more than 35 years ago, the use of supercritical CO{sub 2} as the working fluid in a closed circuit Brayton cycle has so far not been implemented in practice. Industrial experience in several other relevant applications has improved prospects, and its good efficiency at modest temperatures (e.g., {approx}45% at 550 deg. C) make this cycle attractive for a variety of advanced nuclear reactor concepts. The version described here is for a gas-cooled, modular fast reactor. In the proposed gas-cooled fast breeder reactor design of present interest, CO{sub 2} is also especially attractive because it allows the use of metal fuel and core structures. The principal advantage of a supercritical CO{sub 2} Brayton cycle is its reduced compression work compared to an ideal gas such as helium: about 15% of gross power turbine output vs. 40% or so. This also permits the simplification of use of a single compressor stage without inter-cooling. The requisite high pressure ({approx}20 MPa) also has the benefit of more compact heat exchangers and turbines. Finally, CO{sub 2} requires significantly fewer turbine stages than He, its principal competitor for nuclear gas turbine service. One disadvantage of CO{sub 2} in a direct cycle application is the production of N-16, which will require turbine plant shielding (albeit much less than in a BWR). The cycle efficiency is also very sensitive to recuperator effectiveness and compressor inlet temperature. It was found necessary to split the recuperator into separate high-and low-temperature components, and to employ intermediate re-compression, to avoid having a pinch-point in the cold end of the recuperator. Over the past several decades developments have taken place that make the acceptance of supercritical CO{sub 2} systems more likely: supercritical CO{sub 2} pipelines are in use in the western US in oil-recovery operations; 14 advanced gas-cooled reactors (AGR) are employed in the UK at CO{sub 2} temperatures up to

  18. Ultra high resolution tomography

    SciTech Connect

    Haddad, W.S.

    1994-11-15

    Recent work and results on ultra high resolution three dimensional imaging with soft x-rays will be presented. This work is aimed at determining microscopic three dimensional structure of biological and material specimens. Three dimensional reconstructed images of a microscopic test object will be presented; the reconstruction has a resolution on the order of 1000 A in all three dimensions. Preliminary work with biological samples will also be shown, and the experimental and numerical methods used will be discussed.

  19. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2001-04-15

    The objective of this project is to develop an improved ultra-lightweight cement using ultralight hollow glass spheres (ULHS). Work reported herein addresses Task 1: Assess Ultra-Lightweight Cementing Problems and Task 3: Test Ultra-Lightweight Cements. Results reported this quarter include a review and summary of Halliburton Energy Services (HES) and BJ Services historical performance data for lightweight cement applications. These data are analyzed and compared to ULHS cement and foamed cement performances. Similar data is expected from Schlumberger, and an analysis of this data will be completed in the following phases of the project. Quality control testing of materials used to formulate ULHS cements in the laboratory was completed to establish baseline material performance standards. A testing protocol was developed employing standard procedures as well as procedures tailored to evaluate ULHS and foamed cement. This protocol is presented and discussed. Results of further testing of ULHS cements are presented along with an analysis to establish cement performance design criteria to be used during the remainder of the project. Finally, a list of relevant literature on lightweight cement performance is compiled for review during the next quarter.

  20. Characterization of Polyimide Foams for Ultra-Lightweight Space Structures

    NASA Technical Reports Server (NTRS)

    Meador, Michael (Technical Monitor); Hillman, Keithan; Veazie, David R.

    2003-01-01

    Ultra-lightweight materials have played a significant role in nearly every area of human activity ranging from magnetic tapes and artificial organs to atmospheric balloons and space inflatables. The application range of ultra-lightweight materials in past decades has expanded dramatically due to their unsurpassed efficiency in terms of low weight and high compliance properties. A new generation of ultra-lightweight materials involving advanced polymeric materials, such as TEEK (TM) polyimide foams, is beginning to emerge to produce novel performance from ultra-lightweight systems for space applications. As a result, they require that special conditions be fulfilled to ensure adequate structural performance, shape retention, and thermal stability. It is therefore important and essential to develop methodologies for predicting the complex properties of ultra-lightweight foams. To support NASA programs such as the Reusable Launch Vehicle (RLV), Clark Atlanta University, along with SORDAL, Inc., has initiated projects for commercial process development of polyimide foams for the proposed cryogenic tank integrated structure (see figure 1). Fabrication and characterization of high temperature, advanced aerospace-grade polyimide foams and filled foam sandwich composites for specified lifetimes in NASA space applications, as well as quantifying the lifetime of components, are immensely attractive goals. In order to improve the development, durability, safety, and life cycle performance of ultra-lightweight polymeric foams, test methods for the properties are constant concerns in terms of timeliness, reliability, and cost. A major challenge is to identify the mechanisms of failures (i.e., core failure, interfacial debonding, and crack development) that are reflected in the measured properties. The long-term goal of the this research is to develop the tools and capabilities necessary to successfully engineer ultra-lightweight polymeric foams. The desire is to reduce density

  1. Springback analysis of ultra high strength steel

    NASA Astrophysics Data System (ADS)

    Tenma, Kenji; Kina, Futoshi; Suzuki, Wataru

    2013-12-01

    It is an inevitable trend in the automotive industry to apply more and more high strength steels and even ultra-high strength steels. Even though these materials are more difficult to process the development time of forming tools must be reduced. In order to keep the development time under control, simulation tools are used to verify the forming process in advance. At Aoi Machine Industry a project has been executed to accurately simulate springback of ultra-high strength steels in order to reduce the tool tryout time. In the first phase of the project the simulation settings were optimized based on B-Pillar model A made of Dual Phase 980. In the second phase, it was verified with B-Pillar model B whether these simulation settings were usable as general setting. Results showed that with the right settings it is very well possible to accurately simulate springback of ultra-high strength steels. In the third phase the project the stamping of a B-Pillar of Dual Phase 1180 was studied.

  2. Subcritical and supercritical technology for the production of second generation bioethanol.

    PubMed

    Rostagno, Mauricio A; Prado, Juliana M; Mudhoo, Ackmez; Santos, Diego T; Forster-Carneiro, Tânia; Meireles, M Angela A

    2015-01-01

    There is increased interest in reducing our reliance on fossil fuels and increasing the share of renewable raw materials in our energy supply chain due to environmental and economic concerns. Ethanol is emerging as a potential alternative to liquid fuels due to its eco-friendly characteristics and relatively low production costs. As ethanol is currently produced from commodities also used for human and animal consumption, there is an urgent need of identifying renewable raw materials that do not pose a competitive problem. Lignocellulosic agricultural residues are an ideal choice since they can be effectively hydrolyzed to fermentable sugars and integrated in the context of a biorefinery without competing with the food supply chain. However, the conventional hydrolysis methods still have major issues that need to be addressed. These issues are related to the processing rate and generation of fermentation inhibitors, which can compromise the quality of the product and the cost of the process. As the knowledge of the processes taking place during hydrolysis of agricultural residues is increasing, new techniques are being exploited to overcome these drawbacks. This review gives an overview of the state-of-the-art of hydrolysis with subcritical and supercritical water in the context of reusing agricultural residues for the production of suitable substrates to be processed during the fermentative production of bioethanol. Presently, subcritical and/or supercritical water hydrolysis has been found to yield low sugar contents mainly due to concurrent competing degradation of sugars during the hydrothermal processes. In this line of thinking, the present review also revisits the recent applications and advances to provide an insight of future research trends to optimize on the subcritical and supercritical process kinetics. PMID:24494703

  3. Performance improvement options for the supercritical carbon dioxide brayton cycle.

    SciTech Connect

    Moisseytsev, A.; Sienicki, J. J.; Nuclear Engineering Division

    2008-07-17

    The supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle is under development at Argonne National Laboratory as an advanced power conversion technology for Sodium-Cooled Fast Reactors (SFRs) as well as other Generation IV advanced reactors as an alternative to the traditional Rankine steam cycle. For SFRs, the S-CO{sub 2} Brayton cycle eliminates the need to consider sodium-water reactions in the licensing and safety evaluation, reduces the capital cost of the SFR plant, and increases the SFR plant efficiency. Even though the S-CO{sub 2} cycle has been under development for some time and optimal sets of operating parameters have been determined, those earlier development and optimization studies have largely been directed at applications to other systems such as gas-cooled reactors which have higher operating temperatures than SFRs. In addition, little analysis has been carried out to investigate cycle configurations deviating from the selected 'recompression' S-CO{sub 2} cycle configuration. In this work, several possible ways to improve S-CO{sub 2} cycle performance for SFR applications have been identified and analyzed. One set of options incorporates optimization approaches investigated previously, such as variations in the maximum and minimum cycle pressure and minimum cycle temperature, as well as a tradeoff between the component sizes and the cycle performance. In addition, the present investigation also covers options which have received little or no attention in the previous studies. Specific options include a 'multiple-recompression' cycle configuration, intercooling and reheating, as well as liquid-phase CO{sub 2} compression (pumping) either by CO{sub 2} condensation or by a direct transition from the supercritical to the liquid phase. Some of the options considered did not improve the cycle efficiency as could be anticipated beforehand. Those options include: a double recompression cycle, intercooling between the compressor stages, and reheating

  4. Subsonic Ultra Green Aircraft Research

    NASA Technical Reports Server (NTRS)

    Bradley, Marty K.; Droney, Christopher K.

    2011-01-01

    This Final Report summarizes the work accomplished by the Boeing Subsonic Ultra Green Aircraft Research (SUGAR) team in Phase 1, which includes the time period of October 2008 through March 2010. The team consisted of Boeing Research and Technology, Boeing Commercial Airplanes, General Electric, and Georgia Tech. The team completed the development of a comprehensive future scenario for world-wide commercial aviation, selected baseline and advanced configurations for detailed study, generated technology suites for each configuration, conducted detailed performance analysis, calculated noise and emissions, assessed technology risks, and developed technology roadmaps. Five concepts were evaluated in detail: 2008 baseline, N+3 reference, N+3 high span strut braced wing, N+3 gas turbine battery electric concept, and N+3 hybrid wing body. A wide portfolio of technologies was identified to address the NASA N+3 goals. Significant improvements in air traffic management, aerodynamics, materials and structures, aircraft systems, propulsion, and acoustics are needed. Recommendations for Phase 2 concept and technology projects have been identified.

  5. Characterization of cross-linking structures in UV-cured acrylic ester resin by MALDI-MS combined with supercritical methanolysis.

    PubMed

    Matsubara, Hideki; Hata, Shun-Ichiro; Kondo, Yosuke; Ishida, Yasuyuki; Takigawa, Hiroshi; Ohtani, Hajime

    2006-11-01

    The cross-linking structure of the ultra violet (UV)-cured resin prepared from dipentaerithritol hexacrylate (DPHA) was characterized by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) combined with supercritical methanolysis. The MALDI-mass spectrum of the decomposition products obtained by supercritical methanolysis contained a series of peaks of sodium-cationized methyl acrylate (MA) oligomers up to around m/z = 4000 formed through selective cleavage and methylation occurred at ester linkages in UV-cured DPHA. Furthermore, in order to observe widely distributed sequence lengths in the cross-linking junctions, the decomposed products of the cured resin were then fractionated using size exclusion chromatography followed by the MALDI-MS measurements of the individual fractions. The MALDI-mass spectra of the lower molar mass fractions mainly consisted of a series of peaks of MA oligomers around m/z values of several thousands, whereas those of higher molecular weight showed a broad peak up to m/z ca. 180000. The observed distributions of the supercritical methanolysis products suggested that the network junctions in the given UV-cured resin were composed of up to around 2000 acrylate units. PMID:17099270

  6. Radiation hydrodynamics simulations of wide-angle outflows from super-critical accretion disks around black holes

    NASA Astrophysics Data System (ADS)

    Hashizume, Katsuya; Ohsuga, Ken; Kawashima, Tomohisa; Tanaka, Masaomi

    2015-08-01

    By performing two-dimensional radiation hydrodynamics simulations with a large computational domain of 5000 times the Schwarzschild radius, we revealed that wide-angle outflow is launched via the radiation force from the super-critical accretion flows around black holes. The angular size of the outflow, where the radial velocity (vr) exceeds the escape velocity (vesc), increases with an increase of the distance from the black hole. As a result, the mass is blown away with speed of vr > vesc in all directions except for in the vicinity of the equatorial plane, θ = 0°-85°, where θ is the polar angle. The mass ejected from the outer boundary per unit time by the outflow is larger than the mass accretion rate onto the black hole, ˜ 150 LEdd/c2, where LEdd and c are the Eddington luminosity and the speed of light. The kinetic power of such wide-angle high-velocity outflow is comparable to the photon luminosity and is a few times larger than the Eddington luminosity. This corresponds to ˜ 1039-1040 erg s-1 for the stellar mass black holes. Our model is consistent with the observations of shock excited bubbles observed in some ultra-luminous X-ray sources (ULXs), supporting a hypothesis that ULXs are powered by the super-critical accretion onto stellar mass black holes.

  7. 10 MW Supercritical CO2 Turbine Test

    SciTech Connect

    Turchi, Craig

    2014-01-29

    The Supercritical CO2 Turbine Test project was to demonstrate the inherent efficiencies of a supercritical carbon dioxide (s-CO2) power turbine and associated turbomachinery under conditions and at a scale relevant to commercial concentrating solar power (CSP) projects, thereby accelerating the commercial deployment of this new power generation technology. The project involved eight partnering organizations: NREL, Sandia National Laboratories, Echogen Power Systems, Abengoa Solar, University of Wisconsin at Madison, Electric Power Research Institute, Barber-Nichols, and the CSP Program of the U.S. Department of Energy. The multi-year project planned to design, fabricate, and validate an s-CO2 power turbine of nominally 10 MWe that is capable of operation at up to 700°C and operates in a dry-cooled test loop. The project plan consisted of three phases: (1) system design and modeling, (2) fabrication, and (3) testing. The major accomplishments of Phase 1 included: Design of a multistage, axial-flow, s-CO2 power turbine; Design modifications to an existing turbocompressor to provide s-CO2 flow for the test system; Updated equipment and installation costs for the turbomachinery and associated support infrastructure; Development of simulation tools for the test loop itself and for more efficient cycle designs that are of greater commercial interest; Simulation of s-CO2 power cycle integration into molten-nitrate-salt CSP systems indicating a cost benefit of up to 8% in levelized cost of energy; Identification of recuperator cost as a key economic parameter; Corrosion data for multiple alloys at temperatures up to 650ºC in high-pressure CO2 and recommendations for materials-of-construction; and Revised test plan and preliminary operating conditions based on the ongoing tests of related equipment. Phase 1 established that the cost of the facility needed to test the power turbine at its full power and temperature would exceed the planned funding for Phases 2 and 3. Late

  8. Ultra-wideband receiver

    DOEpatents

    McEwan, Thomas E.

    1994-01-01

    An ultra-wideband (UWB) receiver utilizes a strobed input line with a sampler connected to an amplifier. In a differential configuration, .+-.UWB inputs are connected to separate antennas or to two halves of a dipole antenna. The two input lines include samplers which are commonly strobed by a gating pulse with a very low duty cycle. In a single ended configuration, only a single strobed input line and sampler is utilized. The samplers integrate, or average, up to 10,000 pulses to achieve high sensitivity and good rejection of uncorrelated signals.

  9. Ultra-wideband receiver

    DOEpatents

    McEwan, Thomas E.

    1996-01-01

    An ultra-wideband (UWB) receiver utilizes a strobed input line with a sampler connected to an amplifier. In a differential configuration, .+-.UWB inputs are connected to separate antennas or to two halves of a dipole antenna. The two input lines include samplers which are commonly strobed by a gating pulse with a very low duty cycle. In a single ended configuration, only a single strobed input line and sampler is utilized. The samplers integrate, or average, up to 10,000 pulses to achieve high sensitivity and good rejection of uncorrelated signals.

  10. Ultra-wideband receiver

    DOEpatents

    McEwan, T.E.

    1996-06-04

    An ultra-wideband (UWB) receiver utilizes a strobed input line with a sampler connected to an amplifier. In a differential configuration, {+-}UWB inputs are connected to separate antennas or to two halves of a dipole antenna. The two input lines include samplers which are commonly strobed by a gating pulse with a very low duty cycle. In a single ended configuration, only a single strobed input line and sampler is utilized. The samplers integrate, or average, up to 10,000 pulses to achieve high sensitivity and good rejection of uncorrelated signals. 21 figs.

  11. Ultra-wideband receiver

    DOEpatents

    McEwan, T.E.

    1994-09-06

    An ultra-wideband (UWB) receiver utilizes a strobed input line with a sampler connected to an amplifier. In a differential configuration, [+-] UWB inputs are connected to separate antennas or to two halves of a dipole antenna. The two input lines include samplers which are commonly strobed by a gating pulse with a very low duty cycle. In a single ended configuration, only a single strobed input line and sampler is utilized. The samplers integrate, or average, up to 10,000 pulses to achieve high sensitivity and good rejection of uncorrelated signals. 16 figs.

  12. Multiplexed Optical Fiber Sensors for Coal Fired Advanced Fossil Energy Systems

    SciTech Connect

    Wang, Anbo; Pickrell, Gary

    2012-03-31

    This report summarizes technical progress on the program Multiplexed Optical Fiber Sensors for Coal Fired Advanced Fossil Energy Systems funded by the National Energy Technology Laboratory of the U.S. Department of Energy, and performed jointly by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering and the Department of Materials Science and Engineering at Virginia Tech. This three-year project started on October 1, 2008. In the project, a fiber optical sensing system based on intrinsic Fabry-Perot Interferometer (IFPI) was developed for strain and temperature measurements for Ultra Supercritical boiler condition assessment. Investigations were focused on sensor design, fabrication, attachment techniques and novel materials for high temperature and strain measurements. At the start of the project, the technical requirements for the sensing technology were determined together with our industrial partner Alstom Power. As is demonstrated in Chapter 4, all the technical requirements are successfully met. The success of the technology extended beyond laboratory test; its capability was further validated through the field test at DOE NETL, in which the sensors yielded distributed temperature mapping of a testing coupon installed in the turbine test rig. The measurement results agreed well with prior results generated with thermocouples. In this project, significant improvements were made to the IFPI sensor technology by splicing condition optimization, transmission loss reduction, sensor signal demodulation and sensor system design.

  13. Supercritical fluid reactions for coal processing. Quarterly report, January 1, 1996--March 31, 1996

    SciTech Connect

    Eckert, C.A.

    1996-10-01

    Exciting opportunities exist for the application of supercritical fluid (SCF) reactions for the pre-treatment of coal. Utilizing reactants which resemble the organic nitrogen containing components of coal, we propose to develop a method to tailor chemical reactions in supercritical fluid solvents for the specific application of coal denitrogenation. The tautomeric equilibrium of a Schiff base was chosen as the model system and was investigated in supercritical ethane and cosolvent modified supercritical ethane.

  14. Supercritical fluid reactions for coal processing. Quarterly progress report, April 1, 1996--June 30, 1996

    SciTech Connect

    Eckert, C.A.

    1996-11-01

    Exciting opportunities exist for the application of supercritical fluid (SCF) reactions for the pre-treatment of coal. Utilizing reactants which resemble the organic nitrogen containing components of coal, we propose to develop a method to tailor chemical reactions in supercritical fluid solvents for the specific application of coal denitrogenation. The tautomeric equilibrium of a Schiff base was chosen as the model system and was investigated in supercritical ethane and cosolvent modified supercritical ethane.

  15. Reaction kinetics of cellulose hydrolysis in subcritical and supercritical water

    NASA Astrophysics Data System (ADS)

    Olanrewaju, Kazeem Bode

    The uncertainties in the continuous supply of fossil fuels from the crisis-ridden oil-rich region of the world is fast shifting focus on the need to utilize cellulosic biomass and develop more efficient technologies for its conversion to fuels and chemicals. One such technology is the rapid degradation of cellulose in supercritical water without the need for an enzyme or inorganic catalyst such as acid. This project focused on the study of reaction kinetics of cellulose hydrolysis in subcritical and supercritical water. Cellulose reactions at hydrothermal conditions can proceed via the homogeneous route involving dissolution and hydrolysis or the heterogeneous path of surface hydrolysis. The work is divided into three main parts. First, the detailed kinetic analysis of cellulose reactions in micro- and tubular reactors was conducted. Reaction kinetics models were applied, and kinetics parameters at both subcritical and supercritical conditions were evaluated. The second major task was the evaluation of yields of water soluble hydrolysates obtained from the hydrolysis of cellulose and starch in hydrothermal reactors. Lastly, changes in molecular weight distribution due to hydrothermolytic degradation of cellulose were investigated. These changes were also simulated based on different modes of scission, and the pattern generated from simulation was compared with the distribution pattern from experiments. For a better understanding of the reaction kinetics of cellulose in subcritical and supercritical water, a series of reactions was conducted in the microreactor. Hydrolysis of cellulose was performed at subcritical temperatures ranging from 270 to 340 °C (tau = 0.40--0.88 s). For the dissolution of cellulose, the reaction was conducted at supercritical temperatures ranging from 375 to 395 °C (tau = 0.27--0.44 s). The operating pressure for the reactions at both subcritical and supercritical conditions was 5000 psig. The results show that the rate-limiting step in

  16. Ultra-Sensitive Photoreceiver Boosts Data Transmission

    NASA Technical Reports Server (NTRS)

    2007-01-01

    NASA depends on advanced, ultra-sensitive photoreceivers and photodetectors to provide high-data communications and pinpoint image-detection and -recognition capabilities from great distances. In 2003, Epitaxial Technologies LLC was awarded a Small Business Innovation Research (SBIR) contract from Goddard Space Flight Center to address needs for advanced sensor components. Epitaxial developed a photoreciever capable of single proton sensitivity that is also smaller, lighter, and requires less power than its predecessor. This receiver operates in several wavelength ranges; will allow data rate transmissions in the terabit range; and will enhance Earth-based missions for remote sensing of crops and other natural resources, including applications for fluorescence and phosphorescence detection. Widespread military and civilian applications are anticipated, especially through enhancing fiber optic communications, laser imaging, and laser communications.

  17. Silver nanoparticles generated by pulsed laser ablation in supercritical CO2 medium

    NASA Astrophysics Data System (ADS)

    Machmudah, Siti; Sato, Takayuki; Wahyudiono; Sasaki, Mitsuru; Goto, Motonobu

    2012-03-01

    Pulsed laser ablation (PLA) has been widely employed in industrial and biological applications and in other fields. The environmental conditions in which PLA is conducted are important parameters that affect both the solid particle cloud and the deposition produced by the plume. In this work, the generation of nanoparticles (NPs) has been developed by performing PLA of silver (Ag) plates in a supercritical CO2 medium. Ag NPs were successfully generated by allowing the selective generation of clusters. Laser ablation was performed with an excitation wavelength of 532 nm under various pressures and temperatures of CO2 medium. On the basis of the experimental result, both surface of the irradiated Ag plate and structure of Ag NPs were significantly affected by the changes in supercritical CO2 pressure and temperature. With increasing irradiation pressure, plume deposited in the surrounding crater created by the ablation was clearly observed. In Field Emission Scanning Electron Microscopy (FE-SEM) the image of the generated Ag NPs on the silicon wafer and the morphology of Ag particles were basically a sphere-like structure. Ag particles contain NPs with large-varied diameter ranging from 5 nm to 1.2 μm. The bigger Ag NPs melted during the ablation process and then ejected smaller spherical Ag NPs, which formed nanoclusters attached on the molten Ag NPs. The smaller Ag NPs were also formed around the bigger Ag NPs. Based on the results, this new method can also be used to obtain advanced nano-structured materials.

  18. The Supercritical Pile Model for GRBs

    NASA Technical Reports Server (NTRS)

    Kazanas, D.

    2005-01-01

    We present the spectral and temporal radiative signatures expected within the "Supercritical Pile" model of Gamma Ray Bursts (GRB). This model is motivated by the need for a process that provides the dissipation necessary in GRB and presents a well defined scheme for converting the energy stored in the relativistic protons of the Relativistic Blast Waves (RBW) associated with GRB into radiation; at the same time it leads to spectra which exhibit a peak in the burst nuF(sub nu) distribution at an energy E(sub p) approx. equal to 1 MeV in the observer s frame, in agreement with observation and largely independent of the Lorentz factor r of the associated relativistic outflow. Futhermore, this scheme does not require (but does not preclude) acceleration of particles at the shock other than that provided by the isotropization of the flow bulk kinetic energy on the RBW frame. In the present paper we model in detail the evolution of protons, electrons and photons from a RBW to produce detailed spectra of the prompt GRB phase as a function of time from across a very broad range spanning roughly 4 log10Gamma decades in frequency. The model spectra are in general agreement with observations and provide a means for the delineating of the model parameters through direct comparison with trends observed in GRB properties.

  19. Microbial Growth under Supercritical CO2

    PubMed Central

    Peet, Kyle C.; Freedman, Adam J. E.; Hernandez, Hector H.; Britto, Vanya; Boreham, Chris; Ajo-Franklin, Jonathan B.

    2015-01-01

    Growth of microorganisms in environments containing CO2 above its critical point is unexpected due to a combination of deleterious effects, including cytoplasmic acidification and membrane destabilization. Thus, supercritical CO2 (scCO2) is generally regarded as a sterilizing agent. We report isolation of bacteria from three sites targeted for geologic carbon dioxide sequestration (GCS) that are capable of growth in pressurized bioreactors containing scCO2. Analysis of 16S rRNA genes from scCO2 enrichment cultures revealed microbial assemblages of varied complexity, including representatives of the genus Bacillus. Propagation of enrichment cultures under scCO2 headspace led to isolation of six strains corresponding to Bacillus cereus, Bacillus subterraneus, Bacillus amyloliquefaciens, Bacillus safensis, and Bacillus megaterium. Isolates are spore-forming, facultative anaerobes and capable of germination and growth under an scCO2 headspace. In addition to these isolates, several Bacillus type strains grew under scCO2, suggesting that this may be a shared feature of spore-forming Bacillus spp. Our results provide direct evidence of microbial activity at the interface between scCO2 and an aqueous phase. Since microbial activity can influence the key mechanisms for permanent storage of sequestered CO2 (i.e., structural, residual, solubility, and mineral trapping), our work suggests that during GCS microorganisms may grow and catalyze biological reactions that influence the fate and transport of CO2 in the deep subsurface. PMID:25681188

  20. Towards Overhauser DNP in supercritical CO2

    NASA Astrophysics Data System (ADS)

    van Meerten, S. G. J.; Tayler, M. C. D.; Kentgens, A. P. M.; van Bentum, P. J. M.

    2016-06-01

    Overhauser Dynamic Nuclear Polarization (ODNP) is a well known technique to improve NMR sensitivity in the liquid state, where the large polarization of an electron spin is transferred to a nucleus of interest by cross-relaxation. The efficiency of the Overhauser mechanism for dipolar interactions depends critically on fast local translational dynamics at the timescale of the inverse electron Larmor frequency. The maximum polarization enhancement that can be achieved for 1H at high magnetic fields benefits from a low viscosity solvent. In this paper we investigate the option to use supercritical CO2 as a solvent for Overhauser DNP. We have investigated the diffusion constants and longitudinal nuclear relaxation rates of toluene in high pressure CO2. The change in 1H T1 by addition of TEMPO radical was analyzed to determine the Overhauser cross-relaxation in such a mixture, and is compared with calculations based on the Force Free Hard Sphere (FFHS) model. By analyzing the relaxation data within this model we find translational correlation times in the range of 2-4 ps, depending on temperature, pressure and toluene concentration. Such short correlation times may be instrumental for future Overhauser DNP applications at high magnetic fields, as are commonly used in NMR. Preliminary DNP experiments have been performed at 3.4 T on high pressure superheated water and model systems such as toluene in high pressure CO2.

  1. A man-portable supercritical fluid extractor

    SciTech Connect

    Wright, B.W.; Zemanian, T.S.; Lee, R.N.; Wright, C.W.

    1995-12-31

    A new prototype supercritical fluid extraction (SFE) apparatus has been developed for the on-site preparation of solid matrix samples for subsequent organic analysis. The apparatus consists of two parts, each of which satisfy weight and size requirements for portability. They are a generator module that supplies high-pressure carbon dioxide (the source of which is dry ice) and a briefcase containing a pressure regulator, extraction cells, valves for flow control, flow restriction hardware, equipment for sample collection, temperature control devices, and ancillary supplies. The generator module provides carbon dioxide at pressures to 1 kbar ({approximately}14,500 psi), incorporates no moving parts, and allows rapid loading without tools due to novel fingertight closures. Samples are contained in sintered inserts that fit inside three extraction cells that also have rapid, fingertight closures. Analyte collection may be accomplished using liquid solvent or restrictorless rapid depressurization techniques. Control schemes allow operation at a wide variety of pressures and temperatures and the use of static, dynamic, or hybrid static/dynamic extraction strategies. The technical performance of the prototype apparatus was evaluated by comparison of results from the SFE of a soil sample spiked with six to nine organic compounds of environmental interest to Soxhlet extraction.

  2. A man-portable supercritical fluid extractor

    SciTech Connect

    Wright, B.W.; Zemanian, T.S.; Lee, R.N.; Wright, C.W.

    1995-02-01

    A new prototype supercritical fluid extraction (SFE) apparatus has been developed for the on-site preparation of solid matrix samples for subsequent organic analysis. The apparatus consists of two parts, each of which satisfy weight and size requirements for portability. They are a generator module that supplies high-pressure carbon dioxide (the source of which is dry ice) and a briefcase containing a pressure regulator, extraction cells, valves for flow control, flow restriction hardware, equipment for sample collection, temperature control devices, and ancillary supplies. The generator module provides carbon dioxide at pressures to 1 kbar ({approximately}14,500 psi), incorporates no moving parts, and allows rapid loading without tools due to novel fingertight closures. Samples are contained in sintered inserts that fit inside three extraction cells that also have rapid, fingertight closures. Analyte collection can be accomplished using liquid solvent or restrictorless rapid depressurization techniques. Control schemes allow operation at a wide variety of pressures and temperatures and the use of static, dynamic, or hybrid static/dynamic extraction strategies. The technical performance of the prototype apparatus was evaluated by comparison of results from the SFE of a soil sample spiked with six to nine organic compounds of environmental interest to Soxhlet extraction.

  3. Supercritical wing sections 2, volume 108

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Garabedian, P.; Korn, D.; Jameson, A.; Beckmann, M. (Editor); Kuenzi, H. P. (Editor)

    1975-01-01

    A mathematical theory for the design and analysis of supercritical wing sections was previously presented. Examples and computer programs showing how this method works were included. The work on transonics is presented in a more definitive form. For design, a better model of the trailing edge is introduced which should eliminate a loss of fifteen or twenty percent in lift experienced with previous heavily aft loaded models, which is attributed to boundary layer separation. How drag creep can be reduced at off-design conditions is indicated. A rotated finite difference scheme is presented that enables the application of Murman's method of analysis in more or less arbitrary curvilinear coordinate systems. This allows the use of supersonic as well as subsonic free stream Mach numbers and to capture shock waves as far back on an airfoil as desired. Moreover, it leads to an effective three dimensional program for the computation of transonic flow past an oblique wing. In the case of two dimensional flow, the method is extended to take into account the displacement thickness computed by a semi-empirical turbulent boundary layer correction.

  4. The Supercritical Pile Model for GRBs

    NASA Astrophysics Data System (ADS)

    Mastichiadis; Kazanas

    2006-02-01

    We present the spectral and temporal radiative signatures expected withinthe quot;Supercritical Pile\\" model of Gamma Ray Bursts (GRB). This modelis motivated by the need for a process that provides the dissipationnecessary in GRB and presents a well defined scheme for converting theenergy stored in the relativistic protons of theRelativistic Blast Waves (RBW) associated with GRB into radiation; at thesame time it leads to spectra which exhibit a peak in the burst nuF_{nu} distribution at an energy E_p simeq 1 MeV in theobserverapos;s frame, in agreement with observation and largelyindependent of the Lorentz factor Gamma of the associated relativisticoutflow. Futhermore, this scheme does not require (but does notpreclude) acceleration of particles at the shock other than that providedby the isotropization of the flow bulk kinetic energy on the RBW frame. Inthe present paper we model in detail the evolution of protons, electronsand photons from a RBW within the framework of this model to producedetailed spectra of the prompt GRB phase as a function of time from acrossa very broad range spanning roughly 4 log_{10} Gamma decades$ in frequency. The model spectra are in generalagreement with observations and provide a means for the delineating of themodel parameters through direct comparison with trends observed in GRBproperties.

  5. Nonlinear dielectric effect in supercritical diethyl ether

    NASA Astrophysics Data System (ADS)

    Drozd-Rzoska, Aleksandra; Rzoska, Sylwester J.; Martinez-Garcia, Julio Cesar

    2014-09-01

    Nonlinear dielectric effect (NDE) describes changes of dielectric permittivity induced by a strong electric field in a liquid dielectric. The most classical finding related to this magnitude is the negative sign of NDE in liquid diethyl ether (DEE), recalled by Peter Debye in his Nobel Prize lecture. This article shows that the positive sign of NDE in DEE is also possible, in the supercritical domain. Moreover, NDE on approaching the gas-liquid critical point exhibits a unique critical effect described by the critical exponent ψ ≈ 0.4 close to critical temperature (TC) and ψ ≈ 0.6 remote from TC. This can be linked to the emergence of the mean-field behavior in the immediate vicinity of TC, contrary to the typical pattern observed for critical phenomena. The multi-frequency mode of NDE measurements made it possible to estimate the evolution of lifetime of critical fluctuations. The new way of data analysis made it possible to describe the critical effect without a knowledge of the non-critical background contribution in prior.

  6. Towards Overhauser DNP in supercritical CO2.

    PubMed

    van Meerten, S G J; Tayler, M C D; Kentgens, A P M; van Bentum, P J M

    2016-06-01

    Overhauser Dynamic Nuclear Polarization (ODNP) is a well known technique to improve NMR sensitivity in the liquid state, where the large polarization of an electron spin is transferred to a nucleus of interest by cross-relaxation. The efficiency of the Overhauser mechanism for dipolar interactions depends critically on fast local translational dynamics at the timescale of the inverse electron Larmor frequency. The maximum polarization enhancement that can be achieved for (1)H at high magnetic fields benefits from a low viscosity solvent. In this paper we investigate the option to use supercritical CO2 as a solvent for Overhauser DNP. We have investigated the diffusion constants and longitudinal nuclear relaxation rates of toluene in high pressure CO2. The change in (1)H T1 by addition of TEMPO radical was analyzed to determine the Overhauser cross-relaxation in such a mixture, and is compared with calculations based on the Force Free Hard Sphere (FFHS) model. By analyzing the relaxation data within this model we find translational correlation times in the range of 2-4ps, depending on temperature, pressure and toluene concentration. Such short correlation times may be instrumental for future Overhauser DNP applications at high magnetic fields, as are commonly used in NMR. Preliminary DNP experiments have been performed at 3.4T on high pressure superheated water and model systems such as toluene in high pressure CO2. PMID:27082277

  7. Near Term Application of Supercritical Water Technologies

    SciTech Connect

    Vogt, Bastian; Starflinger, Joerg; Schulenberg, Thomas

    2006-07-01

    A pressurized water reactor with a supercritical water primary loop is analyzed (PWR-SC) within this paper. It will be shown that the PWR-SC offers considerable advantages in the fields of safety, economy and efficiency compared with a conventional PWR design. A cycle analysis shows that the net plant efficiency increases by 2% compared to currently operated or built systems. In addition, the mass flow rate of the primary side is strongly decreased, which enables a reduction of the primary pump power by a factor of 4. In the secondary loop, the mass flow rate can be decreased by about 15%, which allows down-scaling of all secondary side components such as turbines, condensers and feed-water preheat systems as a consequence of the high core exit temperature. A coupled core analysis and a hot channel factor analysis are performed to demonstrate the promising safety features of the PWR-SC and to show the technical feasibility of such a system. (authors)

  8. Electrostatic Potential Across Supercritical Collisionless Shock

    NASA Astrophysics Data System (ADS)

    Khotyaintsev, Y. V.; Vaivads, A.; Krasnoselskikh, V.

    2013-12-01

    Using multi-spacecraft Cluster observations of the Earth's bow shock we estimate the electrostatic potential across a supercritical quasi-perpendicular collisionless shock. We find the potential values of the order of several kV, which correspond roughly to the kinetic energy of the inflowing solar wind. It is expected that the plasma flow in the de Hoffmann-Teller frame is field-aligned, and thus the potential computed in this frame is the parallel potential experienced by both ions and electrons. Contrary to this expectation, we show that most of the potential computed in the de Hoffmann-Teller frame is contributed by sub-proton scale Hall electric field, E~JxB/ne, which exists due to decoupling of electron and ion motions at such small scales (ions are demagnetized, and electrons are still well magnetized), and therefore the electron motion in such field is perpendicular to B. In order to calculate the parallel potential drop experienced by electrons, one needs to go to the 'electron' Hoffmann-Teller frame at small scales, in which the JxB/ne field is zero. In this 'electron' frame we find much smaller values of the potential drop across the shock of the order of 100 eV, which is comparable to the change of electron temperature across the shock, and is in agreement with theoretical estimates.

  9. Extraction of metals using supercritical fluid and chelate forming legand

    DOEpatents

    Wai, Chien M.; Laintz, Kenneth E.

    1998-01-01

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

  10. Extraction of metals using supercritical fluid and chelate forming ligand

    DOEpatents

    Wai, C.M.; Laintz, K.E.

    1998-03-24

    A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated {beta}-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated {beta}-diketone and a trialkyl phosphate, or a fluorinated {beta}-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated {beta}-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process. 7 figs.

  11. Synthesis and characterization of nanocrystalline mesoporous zirconia using supercritical drying.

    PubMed

    Tyagi, Beena; Sidhpuria, Kalpesh; Shaik, Basha; Jasra, Raksh Vir

    2006-06-01

    Synthesis of nano-crystalline zirconia aerogel was done by sol-gel technique and supercritical drying using n-propanol solvent at and above supercritical temperature (235-280 degrees C) and pressure (48-52 bar) of n-propanol. Zirconia xerogel samples have also been prepared by conventional thermal drying method to compare with the super critically dried samples. Crystalline phase, crystallite size, surface area, pore volume, and pore size distribution were determined for all the samples in detail to understand the effect of gel drying methods on these properties. Supercritical drying of zirconia gel was observed to give thermally stable, nano-crystalline, tetragonal zirconia aerogels having high specific surface area and porosity with narrow and uniform pore size distribution as compared to thermally dried zirconia. With supercritical drying, zirconia samples show the formation of only mesopores whereas in thermally dried samples, substantial amount of micropores are observed along with mesopores. The samples prepared using supercritical drying yield nano-crystalline zirconia with smaller crystallite size (4-6 nm) as compared to higher crystallite size (13-20 nm) observed with thermally dried zirconia. PMID:17025056

  12. Reverse micelle and microemulsion phases in supercritical fluids

    SciTech Connect

    Fulton, J.L.; Smith, R.D.

    1988-05-19

    The surfactant sodium bis(2-ethylhexyl) sulfosuccinate (AOT) was used to form reverse micelle and microemulsion phases in supercritical ethane and propane for systems consisting of 80-100% alkane by weight. Phase diagrams obtained from view cell studies of microemulsion phases formed in supercritical fluids are reported and shown to be strongly dependent on pressure. The properties of these solutions were also characterized by conductivity, density, and surfactant solubility measurements. The solubility of AOT in ethane and propane over a range of pressures shows behavior typical of solids in supercritical fluids. The maximum water-to-surfactant ratio (W/sub 0/) increased dramatically in both ethane and propane systems as pressure was increased. At 300 bar and 103/sup 0/C, the supercritical propane-surfactant system is capable of solubilizing much more water (W/sub 0/ = 12) than the supercritical ethane-surfactant system (W/sub 0/ = 4) at 300 bar and 37/sup 0/C. Some of the important thermodynamic contributions that are likely responsible for this pressure-dependent phase behavior are discussed, and potential applications of this new class of solvents are considered.

  13. Corrosive effects of supercritical carbon dioxide and cosolvents on metals

    SciTech Connect

    Russick, E.M.; Poulter, G.A.; Adkins, C.L.J.; Sorensen, N.R.

    1994-06-01

    With the eventual phase-out of chlorofluorocarbons, and restrictive regulations concerning the use of cleaning solvents such as hydrochlorofluorocarbons, and other volatile organic compounds, it is essential to seek new, environmentally acceptable cleaning processes. In the DOE Complex and in industry, an environmentally sound process for precision cleaning of machined metal parts is one of the issues that needs to be addressed. At Sandia, we are investigating the use of supercritical carbon dioxide (CO{sub 2}) as an alternative cleaning solvent for this application. Carbon dioxide is nontoxic, recyclable, and relatively inexpensive. Supercritical CO{sub 2} has been demonstrated as a solvent for many nonpolar organic compounds, including hydrocarbon-based machining and lubricating oils. The focus of this work is to investigate any corrosive effects of supercritical CO{sub 2} cleaning on metals. Sample coupons of several common metals were statically exposed to pure supercritical CO{sub 2}, water saturated supercritical CO{sub 2}, and 10 wt % methanol/CO{sub 2} cosolvent at 24,138 kPa (3500 psi) and 323K (50C) for 24 hours. Gravimetric analysis and magnified visual inspection of the coupons were performed before and after the exposure tests. Electron microprobe, x-ray photoelectron spectroscopy (XPS), and Auger electron surface analyses were done as needed where visual and gravimetric changes in the samples were evident. Results are reported.

  14. ULTRA-LIGHTWEIGHT CEMENT

    SciTech Connect

    Fred Sabins

    2003-07-31

    The objective of this project is to develop an improved ultra-lightweight cement using ultra-lightweight hollow glass spheres (ULHS). This report discusses testing that was performed for analyzing the alkali-silica reactivity of ULHS in cement slurries. Laboratory testing during the eleventh quarter focused on evaluation of the alkali-silica reaction of eight different cement compositions, four of which contain ULHS. This report provides a progress summary of ASR testing. The original laboratory procedure for measuring set cement expansion resulted in unacceptable erosion of the test specimens. In subsequent tests, a different expansion procedure was implemented and an alternate curing method for cements formulated with TXI Lightweight cement was employed to prevent sample failure caused by thermal shock. The results obtained with the modified procedure showed improvement over data obtained with the original procedure, but data for some compositions were still questionable. Additional modification of test procedures for compositions containing TXI Lightweight cement were implemented and testing is ongoing.

  15. Topics in Chemical Instrumentation--An Introduction to Supercritical Fluid Chromatography: Part 1: Principles and Instrumentation.

    ERIC Educational Resources Information Center

    Palmieri, Margo D.

    1988-01-01

    Identifies the properties and characteristics of supercritical fluids. Discusses the methodology for supercritical fluid chromatography including flow rate, plate height, column efficiency, viscosity, and other factors. Reviews instruments, column types, and elution conditions. Lists supercritical fluid data for 22 compounds, mostly organic. (MVL)

  16. High Resolution X-ray CMT Imaging of Supercritical CO2 in Porous Media: Experimental Challenges, Solutions, and Results

    NASA Astrophysics Data System (ADS)

    Herring, A. L.; Andersson, L.; Newell, D. L.; Carey, J. W.; Wildenschild, D.

    2013-12-01

    Geologic carbon dioxide (CO2) sequestration has been proposed as a climate change mitigation strategy to limit emissions of CO2 to the atmosphere from large fossil-fuel burning CO2 point sources; however, there are concerns associated with the long-term stability of a mobile subsurface CO2 plume. Capillary trapping of supercritical CO2 (scCO2), wherein the CO2 is held within the pore structure of the geologic matrix by capillary forces, is a more secure form of subsurface storage than structural trapping, which relies on an impermeable caprock to contain the buoyant CO2 plume. To understand the multiphase physics of CO2 transport, and to subsequently produce quantitative estimates of potential CO2 capillary trapping, it is necessary to study field, core, and pore-scale processes. X-ray computed microtomography (x-ray CMT) allows for three-dimensional (3D) in-situ visualization of fluid phases within and the physical structure of a porous medium at the pore-scale. We have designed and built a mobile experimental set-up capable of running at pressures up to 2000 PSI and temperatures up to 50°C, made with materials that are compatible with corrosive fluids. Our experimental procedure includes pressurizing, mixing, and separating fluids; and subsequently running immiscible drainage and imbibition flow experiments with brine and supercritical CO2. With this set-up and procedure, we successfully conducted a brine-scCO2 drainage experiment in Bentheimer sandstone at 1200 PSI and 36°C, and confirmed and quantified CO2 flow in the sandstone core via synchrotron-based x-ray CMT with a resolution of 4.65 μm at the Advanced Photon Source at Argonne National Laboratory. We have proven that we can observe, on a pore-scale basis, the movement of supercritical CO2 within a porous media. The properties of supercritical CO2 (e.g. viscosity, density, interfacial tension and solubility in brine) vary significantly with changes in pressure and temperature; consequently, precise

  17. Experimental trim drag values and flow-field measurements for a wide-body transport model with conventional and supercritical wings

    NASA Technical Reports Server (NTRS)

    Jacobs, P. F.

    1982-01-01

    The purpose of this study was to determine if advanced supercritical wings incur higher trim drag values at cruise conditions than current wide body technology wings. Relative trim drag increments were measured in an experimental wind tunnel investigation conducted in the Langley 8 Foot Transonic Pressure Tunnel. The tests utilized a high aspect ratio supercritical wing and a wide body aircraft wing, in conjunction with five different horizontal tail configurations, mounted on a representative wide body fuselage. The three low tail and two T-tail configurations were designed to measure the effects of horizontal tail size, location, and camber on the trim drag increments for the two wings. Longitudinal force and moment data were taken at a Mach number of 0.82 and design cruise lift coefficients for the wide body and supercritical wings of 0.45 and 0.55, respectively. The data indicate that the supercritical wing does not have significantly higher trim drag than the wide body wing. A reduction in tail size, combined with relaxed static stability, produced trim drag reductions for both wings. The cambered tails had higher trim drag increments than the symmetrical tails for both wings, and the T-tail configurations had lower trim drag increments than the low tail configurations.

  18. Development and evaluation of supercritical fluid chromatography/mass spectrometry for polar and high-molecular-weight coal components. Technical progress report

    SciTech Connect

    Chess, E.K.; Smith, R.D.

    1986-01-01

    This Technical Progress Report reviews the technical progress made over the first 18 months of the program. Our goals include the design, development, and evaluation of a combined capillary column supercritical fluid chromatograph/high-performance mass spectrometer capable of analyzing high-molecular-weight polar materials and evaluating the system's potential for application in coal conversion process monitoring. The program includes not only the development and evaluation of the required instrumentation, but the development of polar fluids and compatible chromatographic stationary phases needed for efficient separation and analysis of polar and high-molecular-weight compounds. A new chromatograph/mass spectrometer interface and new mass spectrometer ion source have been designed, constructed, and evaluated using low-polarity supercritical fluids such as pentane. Results from the evaluations have been used to modify the instrumentation to improve performance. The design and fabrication of capillary flow restrictors from fused silica tubing has been explored. Research has also been conducted toward advancing the technology of fabricating high-performance chromatographic columns suitable for use with polar supercritical fluids. Results to date support our initial belief that high-resolution supercritical fluid chromatography (SFC)/high-performance mass spectrometry (MS) will provide a significantly enhanced analytical capability for broad classes of previously intractable fuel components. 10 refs., 13 figs.

  19. Comparison of supercritical and conventional wing flutter characteristics

    NASA Technical Reports Server (NTRS)

    Farmer, M. G.; Hanson, P. W.

    1976-01-01

    A wind-tunnel study is described in which it was attempted to compare the measured flutter boundaries of two dynamically similar aeroelastic models with identical planform, maximum thickness-to-chord ratio, and as nearly identical stiffness and mass distributions as possible, but with one wing having a supercritical airfoil and the other a conventional one. At subsonic Mach numbers, the flutter boundary for the supercritical wing was above that of the conventional wing, as predicted by flutter calculations using subsonic lifting theory. In the transonic region, however, the supercritical wing boundary decreases more rapidly and the minimum flutter point occurs at a dynamic pressure below the conventional wing boundary. Airfoil shape effects may account for some of the difference in the flutter boundaries of the two airfoils.

  20. The Effect of Supercritical Fluids on Solid Acid Catalyst Alkylation

    SciTech Connect

    Ginosar, Daniel Michael; Thompson, David Neil; Burch, Kyle Coates; Zalewski, D. J.

    2002-05-01

    The alkylation of isobutane with trans-2-butene was explored over six solid acid catalysts in the liquid, near-critical liquid, and supercritical regions through the addition of an inert cosolvent to the reaction feed mixture. The addition of supercritical cosolvents did not result in sustained catalytic alkylation activity. A modest improvement in product yield was obtained with the addition of methane in the modified-liquid region; however, catalyst longevity and product selectivity were decreased compared to cosolvent-free liquid conditions. This paper describes the catalyst screening and selection process, an exploration of catalyst performance with varying concentrations of methane, and an examination of the effects of seven supercritical fluids on catalyst performance. The catalysts included two zeolites, two sulfated metal oxides, and two Nafion catalysts. Three hydrocarbons, two fluorocarbons, carbon dioxide, and sulfur hexafluoride were explored as inert cosolvents added to the reaction mixture.

  1. Application of Neutron Radiography to Flow Visualization in Supercritical Water

    NASA Astrophysics Data System (ADS)

    Takenaka, N.; Sugimoto, K.; Takami, S.; Sugioka, K.; Tsukada, T.; Adschiri, T.; Saito, Y.

    Supercritical water is used in various chemical reaction processes including hydrothermal synthesis of metal oxide nano-particles, oxidation, chemical conversion of biomass and plastics. Density of the super critical water is much less than that of the sub-critical water. By using neutron radiography, Peterson et al. have studied salt precipitation processes in supercritical water and the flow pattern in a reverse-flow vessel for salt precipitation, and Balasko et al. have revealed the behaviour of supercritical water in a container. The nano-particles were made by mixing the super critical flow and the sub critical water solution. In the present study, neutron radiography was applied to the flow visualization of the super and sub critical water mixture in a T-junction made of stainless steel pipes for high pressure and temperature conditions to investigate their mixing process. Still images by a CCD camera were obtained by using the neutron radiography system at B4 port in KUR.

  2. Nonsynchronous vibrations observed in a supercritical power transmission shaft

    NASA Technical Reports Server (NTRS)

    Darlow, M. S.; Zorzi, E. S.

    1979-01-01

    A flexible shaft is prone to a number of vibration phenomena which occur at frequencies other than synchronous with rotational speed. Nonsynchronous vibrations from several sources were observed while running a test rig designed to simulate the operation of a supercritical power transmission shaft. The test rig was run first with very light external damping and then with a higher level of external damping, for comparison. As a result, the effect of external damping on the nonsynchronous vibrations of the test rig was observed. All of these nonsynchronous vibrations were of significant amplitude. Their presence in the vibrations spectra for a supercritical power transmission shaft at various speeds in the operating range indicates that very careful attention to all of the vibration spectra should be made in any supercritical power transmission shafting. This paper presents a review of the analysis performed and a comparison with experimental data. A thorough discussion of the observed nonsynchronous whirl is also provided.

  3. Steric effects and preferential interactions in supercritical carbon dioxide

    SciTech Connect

    Saquing, C.D.; Lucien, F.P.; Foster, N.R

    1998-10-01

    Solubility data are presented for a mixture of o-hydroxybenzoic acid (o-HBA) and m-HBA in supercritical CO{sub 2} doped with 3.5 mol% methanol. The data were measured at 318 and 328 K and for pressures in the range of 101--201 bar. Some new data for the solubility of pure m-HBA in methanol-doped supercritical CO{sub 2} are also presented. The solubilities of the HBA isomers are enhanced considerably with the addition of methanol to supercritical CO{sub 2}. However, the solubility enhancement is strongly affected by the spatial arrangement of their functional groups (steric effect). There appears to be preferential interaction between the solutes and the cosolvent in the quaternary system, and this phenomenon is consistent with thermodynamic modeling of the system.

  4. Solvation effects on reactions of triplet benzophenone in supercritical fluids

    SciTech Connect

    Roberts, C.B.; Brennecke, J.F.; Chateauneuf, J.E.

    1995-05-01

    Laser flash photolysis of the hydrogen abstraction reaction of triplet benzophenone ({sup 3}BP) from 2-propanol and 1,4-cyclohexadiene in supercritical ethane and fluoroform was investigated. Bimolecular rate constants based on bulk concentrations decrease with an increase in pressure along both isotherms studied. These results corroborate previous studies in CO{sub 2} that show increased reaction rates due to enhanced local compositions of cosolvent around the {sup 3}BP solute. Analysis of the results includes prediction of the thermodynamic pressure effect on the rate constant, which suggests an increase in the rate constant with pressure, as well as the effects of increased local cosolvent concentrations about {sup 3}BP. Spectroscopic measurements of the local composition of 2-propanol about a solute in supercritical CO{sub 2} are used to explain the apparent discrepancy between experiment and prediction, providing reasonable evidence that the local environment can influence kinetically controlled reactions in supercritical fluids.

  5. Buffet characteristics of the F-8 supercritical wing airplane

    NASA Technical Reports Server (NTRS)

    Deangelis, V. M.; Monaghan, R. C.

    1977-01-01

    The buffet characteristics of the F-8 supercritical wing airplane were investigated. Wing structural response was used to determine the buffet characteristics of the wing and these characteristics are compared with wind tunnel model data and the wing flow characteristics at transonic speeds. The wingtip accelerometer was used to determine the buffet onset boundary and to measure the buffet intensity characteristics of the airplane. The effects of moderate trailing edge flap deflections on the buffet onset boundary are presented. The supercritical wing flow characteristics were determined from wind tunnel and flight static pressure measurements and from a dynamic pressure sensor mounted on the flight test airplane in the vicinity of the shock wave that formed on the upper surface of the wing at transonic speeds. The comparison of the airplane's structural response data to the supercritical flow characteristics includes the effects of a leading edge vortex generator.

  6. Supercritical extraction of phenols from organically modified smectite

    SciTech Connect

    Park, S.J.; Yeo, S.D.

    1999-01-01

    Supercritical extraction has been performed in a fixed column to desorb phenol and 4-nitrophenol from organically modified smectite. The experiments were carried out in the sequence of adsorption of hexadecyltrimethylammonium (HDTMA) to montmorillonite, adsorption of phenols to organoclay in aqueous solutions, desorption of phenols from loaded organoclay using supercritical carbon dioxide, and adsorption of phenols to regenerated organoclay. The desorption characteristics of phenols were investigated at various pressures up to 420 bar; at temperatures of 40, 60, and 70 C, and at low concentrations of a cosolvent. The extraction percentages of phenols reached up to 90% in 3 hours of extraction. The results showed that under the experimental conditions investigated, the activity of HDTMA was intact during the supercritical extraction of phenols, and hence HDTMA-modified montmorillonite exhibited undiminished adsorption power toward phenols after several regeneration cycles.

  7. Heat transfer research on supercritical water flow upward in tube

    SciTech Connect

    Li, H. B.; Yang, J.; Gu, H. Y.; Zhao, M.; Lu, D. H.; Zhang, J. M.; Wang, F.; Zhang, Y.

    2012-07-01

    The experimental research of heat transfer on supercritical water has been carried out on the supercritical water multipurpose test loop with a 7.6 mm upright tube. The experimental data of heat transfer is obtained. The experimental results of thermal-hydraulic parameters on flow and heat transfer of supercritical water show that: Heat transfer enhancement occurs when the fluid temperature reaches pseudo-critical point with low mass flow velocity, and peters out when the mass flow velocity increases. The heat transfer coefficient and Nusselt number decrease with the heat flux or system pressure increases, and increase with the increasing of mass flow velocity. The wall temperature increases when the mass flow velocity decreases or the system pressure increases. (authors)

  8. Ultra-wideband Communications

    SciTech Connect

    Waltjen, K; Romero, C; Azevedo, S; Dowla, F; Spiridon, A; Benzel, D; Haugen, P

    2004-02-06

    Many applications in wireless communications often require short-range systems capable of rapidly collecting data and transmitting it reliably. Commercial communication systems operate in fixed frequency bands and are easily detectable and are prone to jamming by the enemy, among other shortcomings. The new ultra-wideband (UWB) communications system in the 3.1 to 10 GHz band is of significant interest to a number of Lawrence Livermore National Laboratory (LLNL) programs including the Nonproliferation, Arms Control, and International Security (NAI) Directorate. Ultra-Wideband (UWB) technology has received a significant degree of attention from communications industry since the Federal Communications Commission (FCC) rulings in February 2002. According to FCC, UWB signals have fractional bandwidth (B{sub f}) of 20% or larger at -10 dB cut-off frequencies, with minimum bandwidth of 500 MHz. Unlike traditional communication systems, UWB systems modulate carrier-less, short-duration (picosec to nanosec) pulses to transmit and receive information. A number of programmatic problems at LLNL, particularly in the NAI and other national security Directorates, require collecting information from multiple sensors distributed over a local area. The information must be collected covertly and by wireless means. The sensors produce data using low power devices and the communication link must operate in severe multipath environments over tens of meters; often the links must be channelized to handle multiple sensors. The communications links between these sensors is a critical issue in the development of LLNL programs to demonstrate distributed sensor network performance in real-time. In summary, such systems must be robust; have a low probability of detection and intercept; employ low-power, small-size hardware; and interface easily with other systems for analysis or to establish long-distance links. The purpose of this work was to develop a new UWB radio-frequency (RF

  9. Surfactant/Supercritical Fluid Cleaning of Contaminated Substrates

    NASA Technical Reports Server (NTRS)

    White, Gary L.

    1997-01-01

    CFC's and halogenated hydrocarbon solvents have been the solvents of choice to degrease and otherwise clean precision metal parts to allow proper function. Recent regulations have, however, rendered most of these solvents unacceptable for these purposes. New processes which are being used or which have been proposed to replace these solvents usually either fail to remove water soluble contaminants or produce significant aqueous wastes which must then be disposed of. In this work, a new method for cleaning surfaces will be investigated. Solubility of typical contaminants such as lubricating greases and phosphatizing bath residues will be studied in several surfactant/supercritical fluid solutions. The effect of temperature, pressure, and the composition of the cleaning mixture on the solubility of oily, polar, and ionic contaminants will be investigated. A reverse micellar solution in a supercritical light hydrocarbon solvent will be used to clean samples of industrial wastes. A reverse micellar solution is one where water is dissolved into a non-polar solvent with the aid of a surfactant. The solution will be capable of dissolving both water-soluble contaminants and oil soluble contaminants. Once the contaminants have been dissolved into the solution they will be separated from the light hydrocarbon and precipitated by a relatively small pressure drop and the supercritical solvent will be available for recycle for reuse. The process will be compared to the efficacy of supercritical CO2 cleaning by attempting to clean the same types of substrates and machining wastes with the same contaminants using supercritical CO2. It is anticipated that the supercritical CO2 process will not be capable of removing ionic residues.

  10. Gasification of diesel oil in supercritical water for fuel cells

    NASA Astrophysics Data System (ADS)

    Pinkwart, Karsten; Bayha, Thomas; Lutter, Wolfgang; Krausa, Michael

    Experiments have demonstrated the reforming of hydrocarbons in supercritical water. The hydrocarbons were reformed in a continuously operated tubular V4A reactor. The influences of four different commercial steam reforming catalysts were analysed. The experimental results showed that n-decane can be converted to a hydrogen-rich gas. Furthermore, experiments with diesel oil showed the possibility of fuel conversion at low temperature with commercial steam reforming catalysts. Low temperatures and the use of catalysts lead to inhibition of coke formation during the process. The supercritical reforming offers the possibility of a new low temperature hydrocarbon conversion process to hydrogen for fuel cell applications.

  11. Comparison of supercritical and conventional wing flutter characteristics

    NASA Technical Reports Server (NTRS)

    Farmer, M. G.; Hanson, P. W.; Wynne, E. C.

    1976-01-01

    A wind-tunnel study was undertaken to directly compare the measured flutter boundaries of two dynamically similar aeroelastic models which had the same planform, maximum thickness-to-chord ratio, and as nearly identical stiffness and mass distributions as possible, with one wing having a supercritical airfoil and the other a conventional airfoil. The considerations and problems associated with flutter testing supercritical wing models at or near design lift coefficients are discussed, and the measured transonic boundaries of the two wings are compared with boundaries calculated with a subsonic lifting surface theory.

  12. Is there a third order phase transition for supercritical fluids?

    PubMed

    Zhu, Jinglong; Zhang, Pingwen; Wang, Han; Site, Luigi Delle

    2014-01-01

    We prove that according to Molecular Dynamics (MD) simulations of liquid mixtures of Lennard-Jones (L-J) particles, there is no third order phase transition in the supercritical regime beyond Andrew's critical point. This result is in open contrast with recent theoretical studies and experiments which instead suggest not only its existence but also its universality regarding the chemical nature of the fluid. We argue that our results are solid enough to go beyond the limitations of MD and the generic character of L-J models, thus suggesting a rather smooth liquid-vapor thermodynamic behavior of fluids in supercritical regime. PMID:24410228

  13. Step-wise supercritical extraction of carbonaceous residua

    DOEpatents

    Warzinski, Robert P.

    1987-01-01

    A method of fractionating a mixture containing high boiling carbonaceous material and normally solid mineral matter includes processing with a plurality of different supercritical solvents. The mixture is treated with a first solvent of high critical temperature and solvent capacity to extract a large fraction as solute. The solute is released as liquid from solvent and successively treated with other supercritical solvents of different critical values to extract fractions of differing properties. Fractionation can be supplemented by solute reflux over a temperature gradient, pressure let down in steps and extractions at varying temperature and pressure values.

  14. Supercritical water oxidation - Concept analysis for evolutionary Space Station application

    NASA Technical Reports Server (NTRS)

    Hall, John B., Jr.; Brewer, Dana A.

    1986-01-01

    The ability of a supercritical water oxidation (SCWO) concept to reduce the number of processes needed in an evolutionary Space Station design's Environmental Control and Life Support System (ECLSS), while reducing resupply requirements and enhancing the integration of separate ECLSS functions into a single Supercritical Water Oxidation process, is evaluated. While not feasible for an initial operational capability Space Station, the SCWO's application to the evolutionary Space Station configuration would aid the integration of eight ECLSS functions into a single one, thereby significantly reducing program costs.

  15. High-resolution imaging of the supercritical antisolvent process

    NASA Astrophysics Data System (ADS)

    Bell, Philip W.; Stephens, Amendi P.; Roberts, Christopher B.; Duke, Steve R.

    2005-06-01

    A high-magnification and high-resolution imaging technique was developed for the supercritical fluid antisolvent (SAS) precipitation process. Visualizations of the jet injection, flow patterns, droplets, and particles were obtained in a high-pressure vessel for polylactic acid and budesonide precipitation in supercritical CO2. The results show two regimes for particle production: one where turbulent mixing occurs in gas-like plumes, and another where distinct droplets were observed in the injection. Images are presented to demonstrate the capabilities of the method for examining particle formation theories and for understanding the underlying fluid mechanics, thermodynamics, and mass transport in the SAS process.

  16. Asphaltene reaction via supercritical fluid extraction

    SciTech Connect

    Deo, M.D.; Hanson, F.V.

    1993-03-01

    Supercritical fluid extraction (SFE) of bitumen was carried out in a continuous extractor using propane as the solvent at several temperatures and pressures. The asphaltene contents of the residual fractions in the extractor were compared to the asphaltene content of the original bitumen. Asphaltenes were defined as pentane insolubles in this study. It was found that the absolute asphaltene content of the residual fractions exceeded the asphaltene content of the original bitumen. Even when the asphaltene content was prorated by the weight percent of the residual material, it was found to be higher than the original asphaltene content. The data established that the types of compounds separating as asphaltenes changed as the nature of the mixture was altered by SFE. The data also indicated that it may be inappropriate to perform asphaltene material balances to assess the amount of precipitate. The original asphaltene content of a bitumen that is undergoing compositional changes in a sequence of operations may not be an accurate measure of the precipitating tendency of the bitumen in production and processing operations. The asphaltene content of the residual material varied depending on the extraction conditions and was as much as 3--5 times the original asphaltene content. The asphaltene content of the residual material was a maximum at the most efficient extraction condition which was in the vicinity of the critical temperature of propane. The H/C atomic ratio of the residual fractions was lower compared to the original bitumen, indicating that the ratio of polar to nonpolar compounds may also be important from precipitation considerations. Saturate and aromatic compounds were preferentially extracted and the ratio of asphaltenes to resins increased in the residual fractions relative to the original bitumen.

  17. Asphaltene reaction via supercritical fluid extraction

    SciTech Connect

    Deo, M.D.; Hanson, F.V.

    1993-01-01

    Supercritical fluid extraction (SFE) of bitumen was carried out in a continuous extractor using propane as the solvent at several temperatures and pressures. The asphaltene contents of the residual fractions in the extractor were compared to the asphaltene content of the original bitumen. Asphaltenes were defined as pentane insolubles in this study. It was found that the absolute asphaltene content of the residual fractions exceeded the asphaltene content of the original bitumen. Even when the asphaltene content was prorated by the weight percent of the residual material, it was found to be higher than the original asphaltene content. The data established that the types of compounds separating as asphaltenes changed as the nature of the mixture was altered by SFE. The data also indicated that it may be inappropriate to perform asphaltene material balances to assess the amount of precipitate. The original asphaltene content of a bitumen that is undergoing compositional changes in a sequence of operations may not be an accurate measure of the precipitating tendency of the bitumen in production and processing operations. The asphaltene content of the residual material varied depending on the extraction conditions and was as much as 3--5 times the original asphaltene content. The asphaltene content of the residual material was a maximum at the most efficient extraction condition which was in the vicinity of the critical temperature of propane. The H/C atomic ratio of the residual fractions was lower compared to the original bitumen, indicating that the ratio of polar to nonpolar compounds may also be important from precipitation considerations. Saturate and aromatic compounds were preferentially extracted and the ratio of asphaltenes to resins increased in the residual fractions relative to the original bitumen.

  18. Multidimensional radiative effects in supercritical shocks

    NASA Astrophysics Data System (ADS)

    Leygnac, S.; Lanz, T.; Stehlé, C.; Michaut, C.; Korĉáková, D.

    Recent radiative shocks experiments performed on the LULI laser at Ecole Polytechnique in France (Fleury et al., Lasers and Particle Beams 20, 263, 2002) put in evidence a supercritical shock wave in a xenon gas cell. The structure of these shocks is quite similar to those of accretion shock wave in the case of stellar formation, as indicated in Stehlé and Chieze (SF2A - Paris proceedings, 2002). Some points require further studies like the contribution of the gas excitation/ionization energy to the compression ratio and the understanding of the discrepancy, which was noted between the velocity of the radiative precursor in the experiment and in the 1D simulation. Thus, to understand the physics of the radiative shock waves, the academic case of the stationary shock is particularly interesting. We have thus studied the structure of a radiative shock wave which propagates in an ionized gas. We study the extended Rankine Hugoniot equations in various media with inclusion of radiation pressure and energy and study also the extension of the radiative precursor in the diffusion approximation. We also study the equations of multidimensional radiative transfer for a snapshot of the experimental shock in xenon in order to quantify the radiative losses in the finite experimental cell. This academic approach will help to improve the knowledge of the physical processes which take place in radiative shocks of astrophysical interest, like in the birth and death of stars, and prepare ourselves to define appropriate experiments on future high power lasers like LIL and LMJ in Bordeaux.

  19. Microbial Inactivation by Ultrasound Assisted Supercritical Fluids

    NASA Astrophysics Data System (ADS)

    Benedito, Jose; Ortuño, Carmen; Castillo-Zamudio, Rosa Isela; Mulet, Antonio

    A method combining supercritical carbon dioxide (SC-CO2) and high power ultrasound (HPU) has been developed and tested for microbial/enzyme inactivation purposes, at different process conditions for both liquid and solid matrices. In culture media, using only SC-CO2, the inactivation rate of E. coli and S. cerevisiae increased with pressure and temperature; and the total inactivation (7-8 log-cycles) was attained after 25 and 140 min of SC-CO2 (350 bar, 36 °C) treatment, respectively. Using SC-CO2+HPU, the time for the total inactivation of both microorganisms was reduced to only 1-2 min, at any condition selected. The SC-CO2+HPU inactivation of both microorganisms was slower in juices (avg. 4.9 min) than in culture media (avg. 1.5 min). In solid samples (chicken, turkey ham and dry-cured pork cured ham) treated with SC-CO2 and SC-CO2+HPU, the inactivation rate of E. coli increased with temperature. The application of HPU to the SC-CO2 treatments accelerated the inactivation rate of E. coli and that effect was more pronounced in treatments with isotonic solution surrounding the solid food samples. The application of HPU enhanced the SC-CO2 inactivation mechanisms of microorganisms, generating a vigorous agitation that facilitated the CO2 solubilization and the mass transfer process. The cavitation generated by HPU could damage the cell walls accelerating the extraction of vital constituents and the microbial death. Thus, using the combined technique, reasonable industrial processing times and mild process conditions could be used which could result into a cost reduction and lead to the minimization in the food nutritional and organoleptic changes.

  20. [Fast analysis of indole alkaloids from Evodiae fructus by supercritical fluid chromatography].

    PubMed

    Li, Zhenyu; Fu, Qing; Li, Kuiyong; Liang, Tu; Jin, Yu

    2014-05-01

    A fast chromatographic separation of indole alkaloids from Evodiae fructus was developed by supercritical fluid chromatography (SFC). The initial screening of four stationary phases was investigated with a standard mixture of evodiamine and rutaecarpine, and a complex sample of indole alkaloids prepared from Evodiae fructus as probes. Later, the effects of chromatographic parameters on separation were studied including injection volume, organic modifier, additive, temperature and back pressure. The injection volume had significant impact on the peak shape. With the additives in the mobile phase, slight changes in peak shape and retention time were observed in separation. Variation in organic modifier led to dramatic change in chromatographic behavior. Both decreased temperature and increased back pressure shortened the retention time. Finally, a fast analytical method using SFC, on a Waters ACQUITY UPC2 BEH column, methanol as modifier, under 35 degrees C and 2.07 x 10(7) Pa, was developed to separate a complex sample of indole alkaloids in less than 15 min. Another rapid approach for the separation of a complex sample of indole alkaloids was developed by using ultra-high performance liquid chromatography (UHPLC). As a result, SFC can be used in the separation of natural products, giving high performance, good resolution and fast analysis speed. The difference in selectivity with UHPLC can be used to the development of natural product separation. PMID:25185311

  1. Supercritical fluid extraction of bacterial and archaeal lipid biomarkers from anaerobically digested sludge.

    PubMed

    Hanif, Muhammad; Atsuta, Yoichi; Fujie, Koichi; Daimon, Hiroyuki

    2012-01-01

    Supercritical fluid extraction (SFE) was used in the analysis of bacterial respiratory quinone (RQ), bacterial phospholipid fatty acid (PLFA), and archaeal phospholipid ether lipid (PLEL) from anaerobically digested sludge. Bacterial RQ were determined using ultra performance liquid chromatography (UPLC). Determination of bacterial PLFA and archaeal PLEL was simultaneously performed using gas chromatography-mass spectrometry (GC-MS). The effects of pressure, temperature, and modifier concentration on the total amounts of RQ, PLFA, and PLEL were investigated by 23 experiments with five settings chosen for each variable. The optimal extraction conditions that were obtained through a multiple-response optimization included a pressure of 23.6 MPa, temperature of 77.6 °C, and 10.6% (v/v) of methanol as the modifier. Thirty nine components of microbial lipid biomarkers were identified in the anaerobically digested sludge. Overall, the SFE method proved to be more effective, rapid, and quantitative for simultaneously extracting bacterial and archaeal lipid biomarkers, compared to conventional organic solvent extraction. This work shows the potential application of SFE as a routine method for the comprehensive analysis of microbial community structures in environmental assessments using the lipid biomarkers profile. PMID:22489140

  2. Treatment of sewage sludge in supercritical water and evaluation of the combined process of supercritical water gasification and oxidation.

    PubMed

    Qian, Lili; Wang, Shuzhong; Xu, Donghai; Guo, Yang; Tang, Xingying; Wang, Longfei

    2015-01-01

    Influences of temperature and oxidation coefficient (n) on sewage sludge treatment in supercritical water and its corresponding reaction mechanism were studied. Moreover, the combined process of supercritical water gasification (SCWG) and supercritical water oxidation (SCWO) was also investigated. The results show that ammonia nitrogen, phenols and pyridines are main refractory intermediates. The weight of solid products at 873K and n=4 is only 3.5wt.% of the initial weight, which is lower than that after combustion. Volatile organics in solid phase have almost released at 723K and n=0. Highest yield of combustible gases was obtained at n=0, and H2 yield can reach 11.81mol/kg at 873K. Furthermore, the combination of SCWG at 723K and SCWO at 873K with a total n=1 is feasible for its good effluent quality and low operation costs. PMID:25461006

  3. Development and Testing of an UltraBattery-Equipped Honda Civic

    SciTech Connect

    Donald Karner

    2012-04-01

    The UltraBattery retrofit project DP1.8 and Carbon Enriched project C3, performed by ECOtality North America (ECOtality) and funded by the U.S. Department of Energy (DOE) and the Advanced Lead Acid Battery Consortium (ALABC), are to demonstrate the suitability of advanced lead battery technology in Hybrid Electrical Vehicles (HEVs).

  4. Supercritical CO2 direct cycle Gas Fast Reactor (SC-GFR) concept.

    SciTech Connect

    Wright, Steven Alan; Parma, Edward J., Jr.; Suo-Anttila, Ahti Jorma; Al Rashdan, Ahmad; Tsvetkov, Pavel Valeryevich; Vernon, Milton E.; Fleming, Darryn D.; Rochau, Gary Eugene

    2011-05-01

    This report describes the supercritical carbon dioxide (S-CO{sub 2}) direct cycle gas fast reactor (SC-GFR) concept. The SC-GFR reactor concept was developed to determine the feasibility of a right size reactor (RSR) type concept using S-CO{sub 2} as the working fluid in a direct cycle fast reactor. Scoping analyses were performed for a 200 to 400 MWth reactor and an S-CO{sub 2} Brayton cycle. Although a significant amount of work is still required, this type of reactor concept maintains some potentially significant advantages over ideal gas-cooled systems and liquid metal-cooled systems. The analyses presented in this report show that a relatively small long-life reactor core could be developed that maintains decay heat removal by natural circulation. The concept is based largely on the Advanced Gas Reactor (AGR) commercial power plants operated in the United Kingdom and other GFR concepts.

  5. Calculation of the planar supercritical flow over a NASA supercritical profile

    NASA Technical Reports Server (NTRS)

    Yoshihara, H.; Magnus, R.

    1970-01-01

    An unsteady finite difference procedure was used to calculate the steady inviscid flow over an 11% thickness ratio NASA supercritical profile of LWP 505 at M sub infinity = 0.80 and alpha = 0. An attempt is made to include the viscous effects using a modified form of Head's entrainment method to calculate the turbulent boundary layer. The attempt to predict the viscous effects using the compressible form of Head's integral method with a modified auxiliary equation for the form factors was unsatisfactory. Though a reasonably separation bubble was established on the lower surface, a grossly exaggerated displacement effect resulted downstream of the shock on the upper surface. There clearly is substantial further effort required to evolve a satisfactory boundary layer procedure, which must then be coupled in a still unproven manner with the inviscid procedure.

  6. The UltraFlex solar array qualification testing program

    SciTech Connect

    Jones, P.A.; Harvey, T.J.; Douglas, M.V.

    1995-12-31

    A low-cost, lightweight spacecraft power source can help maximize mission efficiency to meet the realities imposed by today`s reduced space budgets. Solar cell technology advances can improve specific power, however, the issues of large-scale manufacturability and cost diminish their near-term potential. Spacecraft designed in the near future must therefore rely on array advances based on established solar cell technologies to meet the goal of increased specific power at a reasonable cost. A joint ABLE-Spectrolab development program has resulted in just such a solar array, the UltraFlex system. The maturation of the UltraFlex design through a successful flight qualification testing program and the resulting evolution of its performance predictions are reported. End of life (EOL) specific power performance of over 100 W/kg with silicon cells and over 180 W/kg with near term multijunction cells is reported.

  7. Cobalt carbonyl catalyzed olefin hydroformylation in supercritical carbon dioxide

    DOEpatents

    Rathke, Jerome W.; Klingler, Robert J.

    1993-01-01

    A method of olefin hydroformylation is provided wherein an olefin reacts with a carbonyl catalyst and with reaction gases such as hydrogen and carbon monoxide in the presence of a supercritical reaction solvent, such as carbon dioxide. The invention provides higher yields of n-isomer product without the gas-liquid mixing rate limitation seen in conventional Oxo processes using liquid media.

  8. Cobalt carbonyl catalyzed olefin hydroformylation in supercritical carbon dioxide

    DOEpatents

    Rathke, J.W.; Klingler, R.J.

    1993-03-30

    A method of olefin hydroformylation is provided wherein an olefin reacts with a carbonyl catalyst and with reaction gases such as hydrogen and carbon monoxide in the presence of a supercritical reaction solvent, such as carbon dioxide. The invention provides higher yields of n-isomer product without the gas-liquid mixing rate limitation seen in conventional Oxo processes using liquid media.

  9. Oil shale extraction using super-critical extraction

    NASA Technical Reports Server (NTRS)

    Compton, L. E. (Inventor)

    1983-01-01

    Significant improvement in oil shale extraction under supercritical conditions is provided by extracting the shale at a temperature below 400 C, such as from about 250 C to about 350 C, with a solvent having a Hildebrand solubility parameter within 1 to 2 Hb of the solubility parameter for oil shale bitumen.

  10. Thermal analysis of turbulent flow of a supercritical fluid

    NASA Technical Reports Server (NTRS)

    Yamane, E.

    1979-01-01

    The influence of the large variation of thermodynamics and transport properties near the pseudocritical temperature on the heat transfer coefficient of supercritical fluid in turbulent flow was studied. The formation of the characteristics peak in the heat transfer coefficient vs. bulk temperature curve is described, and the necessity of the fluid element at pseudocritical temperature located in the buffer layer is discussed.

  11. Instabilities encountered during heat transfer to a supercritical fluid

    NASA Technical Reports Server (NTRS)

    Cornelius, A. J.

    1969-01-01

    Investigation was made of the unstable behavior of a heat-transfer loop operating at a supercritical pressure. Natural convection operation of the loop, with observations on acoustic and slow oscillatory behavior, was emphasized during testing. The basic cause of both types of behavior appeared to originate in the heated boundary layer.

  12. Preparing Silica Aerogel Monoliths via a Rapid Supercritical Extraction Method

    PubMed Central

    Gorka, Caroline A.

    2014-01-01

    A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10-3 molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes. PMID:24637334

  13. Geologic controls on supercritical geothermal resources above magmatic intrusions

    PubMed Central

    Scott, Samuel; Driesner, Thomas; Weis, Philipp

    2015-01-01

    A new and economically attractive type of geothermal resource was recently discovered in the Krafla volcanic system, Iceland, consisting of supercritical water at 450 °C immediately above a 2-km deep magma body. Although utilizing such supercritical resources could multiply power production from geothermal wells, the abundance, location and size of similar resources are undefined. Here we present the first numerical simulations of supercritical geothermal resource formation, showing that they are an integral part of magma-driven geothermal systems. Potentially exploitable resources form in rocks with a brittle–ductile transition temperature higher than 450 °C, such as basalt. Water temperatures and enthalpies can exceed 400 °C and 3 MJ kg−1, depending on host rock permeability. Conventional high-enthalpy resources result from mixing of ascending supercritical and cooler surrounding water. Our models reproduce the measured thermal conditions of the resource discovered at Krafla. Similar resources may be widespread below conventional high-enthalpy geothermal systems. PMID:26211617

  14. Preparing silica aerogel monoliths via a rapid supercritical extraction method.

    PubMed

    Carroll, Mary K; Anderson, Ann M; Gorka, Caroline A

    2014-01-01

    A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10(-3) molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes. PMID:24637334

  15. Cationic Polymerization of Vegetable Oils in Supercritical Carbon Dioxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polymers derived from vegetable oils have been prepared in supercritical carbon dioxide (scCO2) medium by cationic polymerization. Boron trifluoride diethyl etherate BF3.O(C2H2)2 are used as initiator. Influences of polymerization temperature, initiator amount, and carbon dioxide pressure on the m...

  16. SELECTIVE OXIDATION IN SUPERCRITICAL CARBON DIOXIDE USING CLEAN OXIDANTS

    EPA Science Inventory

    We have systematically investigated heterogeneous catalytic oxidation of different substrates in supercritical carbon dioxide (SC-CO2). Three types of catagysts: a metal complex, 0.5% platinum g-alumina and 0.5% palladium g-alumina were used at a pressure of 200 bar, temperatures...

  17. Supercritical carbon dioxide process for pasteurization of fruit juices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Supercritical carbon dioxide (SCCO2) nonthermal processing inactivates microorganisms in juices using non-toxic and non-reactive CO2. However, data is lacking on the inactivation of E. coli K12 and L. plantarum in apple cider using pilot plant scale SCCO2 equipment. For this study, pasteurized pres...

  18. Promising flame retardant textile in supercritical carbon dioxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since carbon dioxide is non-toxic, non-flammable and cost-effective, supercritical carbon dioxide (scCO2) is widely used in textile dyeing applications. Due to its environmentally benign character, scCO2 is considered in green chemistry as a substitute for organic solvents in chemical reactions. O...

  19. Extraction of pesticides from contaminated soil using supercritical carbon dioxide

    SciTech Connect

    Hunter, G.B.

    1991-01-01

    The demand for processes to clean up contaminated soils without generating additional contaminants, such as hazardous solvents, is increasing. One approach to minimizing this problem is to use supercritical fluids like light hydrocarbons and CO[sub 2] to extract contaminants from soils. Gases exhibit unique properties under supercritical conditions. They retain the ability to diffuse through the interstitial spaces of solid materials, plus they have the solvating power of liquids. Some examples of extractions using SCFs are caffeine from coffee, cholesterol from eggs, drugs from plants, and nicotine from tobacco. Supercritical CO[sub 2] is an attractive, alternative extraction medium for removal of pesticides from soils. Carbon dioxide is readily available, relatively inexpensive, and if recycled, nonpolluting. Contaminants may be easily recovered by evaporating the CO[sub 2] into an expansion vessel. Supercritical fluid extraction technology is discussed and results are given for the extraction of atrazine, bentazon, alachlor, and permethrin from contaminated soil prepared in the laboratory. Initial studies show >95% removal for these pesticides.

  20. Extraction of pesticides from contaminated soil using supercritical carbon dioxide

    SciTech Connect

    Hunter, G.B.

    1991-12-31

    The demand for processes to clean up contaminated soils without generating additional contaminants, such as hazardous solvents, is increasing. One approach to minimizing this problem is to use supercritical fluids like light hydrocarbons and CO{sub 2} to extract contaminants from soils. Gases exhibit unique properties under supercritical conditions. They retain the ability to diffuse through the interstitial spaces of solid materials, plus they have the solvating power of liquids. Some examples of extractions using SCFs are caffeine from coffee, cholesterol from eggs, drugs from plants, and nicotine from tobacco. Supercritical CO{sub 2} is an attractive, alternative extraction medium for removal of pesticides from soils. Carbon dioxide is readily available, relatively inexpensive, and if recycled, nonpolluting. Contaminants may be easily recovered by evaporating the CO{sub 2} into an expansion vessel. Supercritical fluid extraction technology is discussed and results are given for the extraction of atrazine, bentazon, alachlor, and permethrin from contaminated soil prepared in the laboratory. Initial studies show >95% removal for these pesticides.

  1. Disintegration of fluids under supercritical conditions from mixing layer studies

    NASA Technical Reports Server (NTRS)

    Okong'o, N.; Bellan, J.

    2003-01-01

    Databases of transitional states obtained from Direct Numerical simulations (DNS) of temporal, supercritical mixing layers for two species systems, O2/H2 and C7H16/N2, are analyzed to elucidate species-specific turbulence aspects and features of fluid disintegration.

  2. Supercritical fluid extraction in plant essential and volatile oil analysis.

    PubMed

    Pourmortazavi, Seied Mahdi; Hajimirsadeghi, Seiedeh Somayyeh

    2007-09-01

    The use of supercritical fluids, especially carbon dioxide, in the extraction of plant volatile components has increased during two last decades due to the expected advantages of the supercritical extraction process. Supercritical fluid extraction (SFE) is a rapid, selective and convenient method for sample preparation prior to the analysis of compounds in the volatile product of plant matrices. Also, SFE is a simple, inexpensive, fast, effective and virtually solvent-free sample pretreatment technique. This review provides a detailed and updated discussion of the developments, modes and applications of SFE in the isolation of essential oils from plant matrices. SFE is usually performed with pure or modified carbon dioxide, which facilitates off-line collection of extracts and on-line coupling with other analytical methods such as gas, liquid and supercritical fluid chromatography. In this review, we showed that a number of factors influence extraction yields, these being solubility of the solute in the fluid, diffusion through the matrix and collection process. Finally, SFE has been compared with conventional extraction methods in terms of selectivity, rapidity, cleanliness and possibility of manipulating the composition of the extract. PMID:17624357

  3. Observation of laser driven supercritical radiative shock precursors.

    PubMed

    Bouquet, S; Stéhlé, C; Koenig, M; Chièze, J-P; Benuzzi-Mounaix, A; Batani, D; Leygnac, S; Fleury, X; Merdji, H; Michaut, C; Thais, F; Grandjouan, N; Hall, T; Henry, E; Malka, V; Lafon, J-P J

    2004-06-01

    We present a supercritical radiative shock experiment performed with the LULI nanosecond laser facility. Using targets filled with xenon gas at low pressure, the propagation of a strong shock with a radiative precursor is evidenced. The main measured shock quantities (electronic density and propagation velocity) are shown to be in good agreement with theory and numerical simulations. PMID:15245230

  4. Fischer-Tropsch synthesis in supercritical reaction media

    SciTech Connect

    Subramaniam, B.; Bochniak, D.; Snavely, K.

    1993-01-01

    Our goals for this quarter were to complete construction of the reactor and analytical units for carrying out Fischer-Tropsch (F-T) synthesis in liquid (n-hexadecane) and in supercritical n-hexane phases. Progress during this quarter was slower than expected.

  5. Method for nucleic acid isolation using supercritical fluids

    DOEpatents

    Nivens, D.E.; Applegate, B.M.

    1999-07-13

    A method is disclosed for detecting the presence of a microorganism in an environmental sample involves contacting the sample with a supercritical fluid to isolate nucleic acid from the microorganism, then detecting the presence of a particular sequence within the isolated nucleic acid. The nucleic acid may optionally be subjected to further purification. 4 figs.

  6. Treatment of municipal sewage sludge in supercritical water: A review.

    PubMed

    Qian, Lili; Wang, Shuzhong; Xu, Donghai; Guo, Yang; Tang, Xingying; Wang, Laisheng

    2016-02-01

    With increasing construction of wastewater treatment plants and stricter policies, municipal sewage sludge (MSS) disposal has become a serious problem. Treatment of MSS in supercritical water (SCW) can avoid the pre-drying procedure and secondary pollution of conventional methods. SCW treatment methods can be divided into supercritical water gasification (SCWG), supercritical water partial oxidation (SCWPO) and supercritical water oxidation (SCWO) technologies with increasing amounts of oxidants. Hydrogen-rich gases can be generated from MSS by SCWG or SCWPO technology using oxidants less than stoichiometric ratio while organic compounds can be completely degraded by SCWO technology with using an oxidant excess. For SCWG and SCWPO technologies, this paper reviews the influences of different process variables (MSS properties, moisture content, temperature, oxidant amount and catalysts) on the production of gases. For SCWO technology, this paper reviews research regarding the removal of organics with or without hydrothermal flames and the changes in heavy metal speciation and risk. Finally, typical systems for handling MSS are summarized and research needs and challenges are proposed. PMID:26645649

  7. Supercritical water oxidation data acquisition testing. Final report, Volume I

    SciTech Connect

    1996-11-01

    This report discusses the phase one testing of a data acquisition system for a supercritical water waste oxidation system. The system is designed to destroy a wide range of organic materials in mixed wastes. The design and testing of the MODAR Oxidizer is discussed. An analysis of the optimized runs is included.

  8. Impregnation of Fenofibrate on mesoporous silica using supercritical carbon dioxide.

    PubMed

    Bouledjouidja, Abir; Masmoudi, Yasmine; Van Speybroeck, Michiel; Schueller, Laurent; Badens, Elisabeth

    2016-02-29

    Low oral bioavailability can be circumvented by the formulation of the poorly water soluble drug in ordered mesoporous silica (OMS-L-7). Fenofibrate is an orally administered, poorly water-soluble active pharmaceutical ingredient (API), used clinically to lower lipid levels. Fenofibrate was loaded into silica using two methods: incipient wetness and supercritical impregnation. This study investigates the impact of loading and the impact of varying supercritical carbon dioxide (scCO2) processing conditions. The objective is to enhance Fenofibrate loading into silica while reducing degree of the drug crystallinity, so as to increase the drug's dissolution rate and its bioavailability. The comparison of both impregnation processes was made in terms of impregnation yields and duration as well as physical characterization of the drug. While incipient wetness method led to a Fenofibrate loading up to 300 mgdrug/gsilica in 48 h of impregnation, the supercritical impregnation method yielded loading up to 485 mgdrug/gsilica in 120 min of impregnation duration, at 16 MPa and 308 K, with a low degree of crystallinity (about 1%) comparable to the crystallinity observed via the solvent method. In addition to the enhancement of impregnation efficiency, the supercritical route provides a solvent-free alternative for impregnation. PMID:26732521

  9. Supercritical fluid extraction and bioactivity of cedarwood oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Supercritical carbon dioxide (70°C, 4,000 psi) was used to extract cedarwood oil from Eastern redcedar, Juniperus virginiana L. The CO2-derived oil was tested for biological activity against several species of arthropods, including mosquitoes, ticks, houseflies, and ants. The cedarwood oil was found...

  10. Method for nucleic acid isolation using supercritical fluids

    DOEpatents

    Nivens, David E.; Applegate, Bruce M.

    1999-01-01

    A method for detecting the presence of a microorganism in an environmental sample involves contacting the sample with a supercritical fluid to isolate nucleic acid from the microorganism, then detecting the presence of a particular sequence within the isolated nucleic acid. The nucleic acid may optionally be subjected to further purification.

  11. Cobalt carbonyl catalyzed olefin hydroformylation in supercritical carbon dioxide

    SciTech Connect

    Rathke, J.W.; Klingler, R.J.

    1992-12-31

    A method of olefin hydroformylation is provided wherein an olefin reacts with a carbonyl catalyst and with reaction gases such as hydrogen and carbon monoxide in the presence of a supercritical reaction solvent, such as carbon dioxide. The invention provides higher yields of n-isomer product without the gas-liquid mixing rate limitation seen in conventional Oxo processes using liquid media.

  12. Geologic controls on supercritical geothermal resources above magmatic intrusions.

    PubMed

    Scott, Samuel; Driesner, Thomas; Weis, Philipp

    2015-01-01

    A new and economically attractive type of geothermal resource was recently discovered in the Krafla volcanic system, Iceland, consisting of supercritical water at 450 °C immediately above a 2-km deep magma body. Although utilizing such supercritical resources could multiply power production from geothermal wells, the abundance, location and size of similar resources are undefined. Here we present the first numerical simulations of supercritical geothermal resource formation, showing that they are an integral part of magma-driven geothermal systems. Potentially exploitable resources form in rocks with a brittle-ductile transition temperature higher than 450 °C, such as basalt. Water temperatures and enthalpies can exceed 400 °C and 3 MJ kg(-1), depending on host rock permeability. Conventional high-enthalpy resources result from mixing of ascending supercritical and cooler surrounding water. Our models reproduce the measured thermal conditions of the resource discovered at Krafla. Similar resources may be widespread below conventional high-enthalpy geothermal systems. PMID:26211617

  13. Methods for deploying ultra-clean detectors

    NASA Astrophysics Data System (ADS)

    Schubert, Alexis

    2008-04-01

    Next-generation underground experiments, such as searches for neutrinoless double-beta decay and dark matter experiments, will perform high-sensitivity measurements that require extremely low backgrounds. The Majo-ra-na Collaboration ootnotetextF.T. Avignone III (2007) arXiv:0711.4808v1 proposes such an experiment to search for neutrinoless double-beta decay using an array of germanium crystals enriched in ^76Ge. The design of the Majo-ra-na experiment must minimize backgrounds while meeting criteria for electrical signal quality, structural integrity, and thermal cooling characteristics. Recent work has addressed detector deployment in ultra low-background environments. Advances have been made in fabrication of radiologically pure copper parts. Prototype designs for detector support structures reduce backgrounds by minimizing component mass and making use of ultra-pure materials. This talk will describe the design and use of cryostat test-stands to investigate the performance of prototype designs for detector strings. While Majo-ra-na uses germanium detectors, the design considerations and progress made by the collaboration are applicable to other detector technologies and fields of research.

  14. Effects of fluid dynamics on cleaning efficacy of supercritical fluids

    SciTech Connect

    Phelps, M.R.; Willcox, W.A.; Silva, L.J.; Butner, R.S.

    1993-03-01

    Pacific Northwest Laboratory (PNL) and Boeing Aerospace Company are developing a process to clean metal parts using a supercritical solvent. This work is part of an effort to address issues inhibiting the rapid commercialization of Supercritical Fluid Parts Cleaning (SFPC). PNL assembled a SFPC test stand to observe the relationship between the fluid dynamics of the system and the mass transfer of a contaminant from the surface of a contaminated metal coupon into the bulk fluid. The bench-scale test stand consists of a Berty'' autoclave modified for these tests and supporting hardware to achieve supercritical fluids parts cleaning. Three separate sets of tests were conducted using supercritical carbon dioxide. For the first two tests, a single stainless steel coupon was cleaned with organic solvents to remove surface residue, doped with a single contaminant, and then cleaned in the SFPC test stand. Contaminants studied were Dow Corning 200 fluid (dimethylpolysiloxane) and Castle/Sybron X-448 High-temperature Oil (a polybutane/mineral oil mixture). A set of 5-minute cleaning runs was conducted for each dopant at various autoclave impeller speeds. Test results from the first two sets of experiments indicate that precision cleaning for difficult-to-remove contaminants can be dramatically improved by introducing and increasing turbulence within the system. Metal coupons that had been previously doped with aircraft oil were used in a third set of tests. The coupons were placed in the SFPC test stand and subjected to different temperatures, pressures, and run times at a constant impeller speed. The cleanliness of each part was measured by Optically Stimulated Electron Emission. The third set of tests show that levels of cleanliness attained with supercritical carbon dioxide compare favorably with solvent and aqueous cleaning levels.

  15. Effects of fluid dynamics on cleaning efficacy of supercritical fluids

    SciTech Connect

    Phelps, M.R.; Willcox, W.A.; Silva, L.J.; Butner, R.S.

    1993-03-01

    Pacific Northwest Laboratory (PNL) and Boeing Aerospace Company are developing a process to clean metal parts using a supercritical solvent. This work is part of an effort to address issues inhibiting the rapid commercialization of Supercritical Fluid Parts Cleaning (SFPC). PNL assembled a SFPC test stand to observe the relationship between the fluid dynamics of the system and the mass transfer of a contaminant from the surface of a contaminated metal coupon into the bulk fluid. The bench-scale test stand consists of a ``Berty`` autoclave modified for these tests and supporting hardware to achieve supercritical fluids parts cleaning. Three separate sets of tests were conducted using supercritical carbon dioxide. For the first two tests, a single stainless steel coupon was cleaned with organic solvents to remove surface residue, doped with a single contaminant, and then cleaned in the SFPC test stand. Contaminants studied were Dow Corning 200 fluid (dimethylpolysiloxane) and Castle/Sybron X-448 High-temperature Oil (a polybutane/mineral oil mixture). A set of 5-minute cleaning runs was conducted for each dopant at various autoclave impeller speeds. Test results from the first two sets of experiments indicate that precision cleaning for difficult-to-remove contaminants can be dramatically improved by introducing and increasing turbulence within the system. Metal coupons that had been previously doped with aircraft oil were used in a third set of tests. The coupons were placed in the SFPC test stand and subjected to different temperatures, pressures, and run times at a constant impeller speed. The cleanliness of each part was measured by Optically Stimulated Electron Emission. The third set of tests show that levels of cleanliness attained with supercritical carbon dioxide compare favorably with solvent and aqueous cleaning levels.

  16. Pulsed corona discharge at atmospheric and supercritical conditions

    NASA Astrophysics Data System (ADS)

    Lock, Evgeniya Hristova

    Pulsed corona discharge is one of the non-equilibrium plasma techniques, by which electrical power is mainly utilized to generate high-energy electrons. These react further with the background gas to produce radicals, which can be further employed in chemically selective reactions. Study of the initiation of pulsed corona discharge in carbon dioxide and air was conducted. Furthermore due to its high removal efficiency, energy yields and good economy, the pulsed corona discharge was employed for removal of methanol and dimethyl sulfide. These compounds are part of the volatile organic compounds (VOC) air pollutants, which are subject of severe environmental regulations due to their toxicity, environmental persistence and intensity of smell. The study provides experimental data for the destruction of methanol and dimethyl sulfide from dry and humid air streams. The effects of the process parameters, including applied voltage, pulse repetition rate, initial concentration of pollutants, temperature and humidity on the destruction and removal efficiency and energy cost are analyzed. Specific consideration is given to the formation of unwanted byproducts. The study on plasma application for pollution control showed that small amounts of dispersed liquid droplets increase the efficiency of the chemical utilization of the high-energy electrons and reduce the required power. So media that could facilitate homogeneous and heterogeneous chemistry at the same time would enhance the efficiency of the removal process. Such medium that has properties intermediate between the gas and liquid phase is the supercritical fluid. Generation of plasma in supercritical fluids is an unexplored area in plasma science. The generation of plasma at elevated pressures usually requires high voltages or small interelectrode distances. The supercritical phase is characterized by extensive cluster formation in the vicinity of the critical point. Typically the clusters have lower ionization

  17. An ultra-uniform ultra-thin resist deposition process

    NASA Astrophysics Data System (ADS)

    Picard, Gilles; Schneider, Juan; Grenon, Brian J.

    2006-10-01

    An ultra-uniform, ultra-thin resist deposition process is presented. Nanometrix applications development with Ultra Thin Polymer Films (UTPF) production process addresses several problems related to resist deposition for lithographic applications. The linear coating process based on the Schneider-Picard (SP) method is a driven assembly process. Linear meter per minute coating rates are produced while providing an outstanding film quality at nano- to micro scale thinness. Therefore, this coating method provides a viable alternative for resist application. Our present developments on nano and micro ultra-thin polymer film coatings give substantial new solutions for improved, faster and less expensive coating production. Materials, writing and quality control costs may be substantially reduced with UTPF deposition technology. Results from three resists are presented in this paper. E-beam direct writing on 8 nm PMMA and photolithography on ILine and DUV resists in the scale of 30 nm are presented. Thicker resist deposition has been performed as well in the range of 1-10 microns thick. Film edge bead in the order of film thickness are obtained (1000 x smaller than spin coating process). Substrates were all coated with uniform ultra-thin films at a rate of one square meter per minute with atomic smoothness. This technological breakthrough enables a valuable solution for resist deposition and lithography fabrication at the nano and micro scales and provides resist uniformity required for current and future critical dimension specifications.

  18. Dynamics of Wetting of Ultra Hydrophobic Surfaces

    NASA Astrophysics Data System (ADS)

    Mohammad Karim, Alireza; Kim, Jeong-Hyun; Rothstein, Jonathan; Kavehpour, Pirouz; Mechanical and Industrial Engineering, University of Massachusetts, Amherst Collaboration

    2013-11-01

    Controlling the surface wettability of hydrophobic and super hydrophobic surfaces has extensive industrial applications ranging from coating, painting and printing technology and waterproof clothing to efficiency increase in power and water plants. This requires enhancing the knowledge about the dynamics of wetting on these hydrophobic surfaces. We have done experimental investigation on the dynamics of wetting on hydrophobic surfaces by looking deeply in to the dependency of the dynamic contact angles both advancing and receding on the velocity of the three-phase boundary (Solid/Liquid/Gas interface) using the Wilhelmy plate method with different ultra-hydrophobic surfaces. Several fluids with different surface tension and viscosity are used to study the effect of physical properties of liquids on the governing laws.

  19. Feasibility Study of Supercritical Light Water Cooled Reactors for Electric Power Production, Progress Report for Work Through September 2003, 2nd Annual/8th Quarterly Report

    SciTech Connect

    Philip E. MacDonald

    2003-09-01

    The supercritical water-cooled reactor (SCWR) is one of the six reactor technologies selected for research and development under the Generation-IV program. SCWRs are promising advanced nuclear systems because of their high thermal efficiency (i.e., about 45% vs. about 33% efficiency for current Light Water Reactors, LWRs) and considerable plant simplification. SCWRs are basically LWRs operating at higher pressure and temperatures with a direct once-through cycle. Operation above the critical pressure eliminates coolant boiling, so the coolant remains single-phase throughout the system. Thus the need for recirculation and jet pumps, a pressurizer, steam generators, steam separators and dryers is eliminated. The main mission of the SCWR is generation of low-cost electricity. It is built upon two proven technologies, LWRs, which are the most commonly deployed power generating reactors in the world, and supercritical fossil-fired boilers, a large number of which is also in use around the world.

  20. Supercritical Water Reactor Cycle for Medium Power Applications

    SciTech Connect

    BD Middleton; J Buongiorno

    2007-04-25

    Scoping studies for a power conversion system based on a direct-cycle supercritical water reactor have been conducted. The electric power range of interest is 5-30 MWe with a design point of 20 MWe. The overall design objective is to develop a system that has minimized physical size and performs satisfactorily over a broad range of operating conditions. The design constraints are as follows: Net cycle thermal efficiency {ge}20%; Steam turbine outlet quality {ge}90%; and Pumping power {le}2500 kW (at nominal conditions). Three basic cycle configurations were analyzed. Listed in order of increased plant complexity, they are: (1) Simple supercritical Rankine cycle; (2) All-supercritical Brayton cycle; and (3) Supercritical Rankine cycle with feedwater preheating. The sensitivity of these three configurations to various parameters, such as reactor exit temperature, reactor pressure, condenser pressure, etc., was assessed. The Thermoflex software package was used for this task. The results are as follows: (a) The simple supercritical Rankine cycle offers the greatest hardware simplification, but its high reactor temperature rise and reactor outlet temperature may pose serious problems from the viewpoint of thermal stresses, stability and materials in the core. (b) The all-supercritical Brayton cycle is not a contender, due to its poor thermal efficiency. (c) The supercritical Rankine cycle with feedwater preheating affords acceptable thermal efficiency with lower reactor temperature rise and outlet temperature. (d) The use of a moisture separator improves the performance of the supercritical Rankine cycle with feedwater preheating and allows for a further reduction of the reactor outlet temperature, thus it was selected for the next step. Preliminary engineering design of the supercritical Rankine cycle with feedwater preheating and moisture separation was performed. All major components including the turbine, feedwater heater, feedwater pump, condenser, condenser pump

  1. Remediation of Contaminated Soils By Supercritical Carbon Dioxide Extraction

    NASA Astrophysics Data System (ADS)

    Ferri, A.; Zanetti, M. C.; Banchero, M.; Fiore, S.; Manna, L.

    The contaminants that can be found in soils are many, inorganic, like heavy metals, as well as organic. Among the organic contaminants, oil and coal refineries are responsi- ble for several cases of soil contamination with PAHs (Polycyclic Aromatic Hydrocar- bons). Polynuclear aromatic hydrocarbons (PAHs) have toxic, carcinogenic and mu- tagenic effects. Limits have been set on the concentration of most contaminants, and growing concern is focusing on soil contamination issues. USA regulations set the maximum acceptable level of contamination by PAHs equal to 40 ppm at residential sites and 270 ppm at industrial sites. Stricter values are usually adopted in European Countries. Supercritical carbon dioxide extraction is a possible alternative technology to remove volatile organic compounds from contaminated soils. Supercritical fluid extraction (SFE) offers many advantages over conventional solvent extraction. Super- critical fluids combine gaseous properties as a high diffusion coefficient, and liquid properties as a high solvent power. The solvent power is strongly pressure-dependent near supercritical conditions: selective extractions are possible without changing the solvent. Solute can be separate from the solvent depressurising the system; therefore, it is possible to recycle the solvent and recover the contaminant. Carbon dioxide is frequently used as supercritical fluid, because it has moderate critical conditions, it is inert and available in pure form. In this work, supercritical fluid extraction technology has been used to remove a polynuclear aromatic hydrocarbon from contaminated soils. The contaminant choice for the experiment has been naphthalene since several data are available in literature. G. A. Montero et al. [1] studied soil remediation with supercrit- ical carbon dioxide extraction technology; these Authors have found that there was a mass-transfer limitation. In the extraction vessel, the mass transfer coefficient in- creases with the

  2. Use of Supercritical Sterilized Bone Allograft in Two Stage Revision ACL Reconstruction

    PubMed Central

    Roe, Justin; Rutten, Sjoerd; Bonnar, Fiona; Salmon, Lucy; Pinczewski, Leo

    2016-01-01

    Objectives: Revision ACL-reconstruction can be compromised by bone loss as result of tunnel widening or poorly placed tunnels. Two-stage revision ACL consist of initial removal of the old fixation hardware and remaining ACL-graft tissue, followed by bone grafting of the tunnels. After a period of graft incorporation and bone remodeling, an ACL-reconstruction is performed. Our primary aim is to examine the use of supercritical carbon dioxide sterilized bone allograft for tunnel grafting in order to determine the bone quality, graft incorporation and remodeling, by using histology and histomorphometric analysis. Secondarily, we aimed to determine whether the histological findings correlate with the timing of the second stage revision procedure. Methods: Case Series. 12 subjects underwent 2-stage revision ACL reconstruction. Femoral and tibial tunnels were bone grafted with supercritical carbon dioxide sterilized bone allograft (Australian Biotechnologies). Mean time from bone grafting to 2nd stage was 8.8 months (range, 5.6 to 21.3 months). Bone biopsies were taken at the time of the 2nd surgery and decalcified and embedded in paraffin. Sections were hematoxylin and eosin stained for microscopic analysis. Results: The graft material was easily identified by its necrotic appearance with empty osteocytes lacunes within the lamellar trabecular bone. In all tissue samples predominately lamellar host bone apposition was seen on the surface of graft fragments known as creeping substitution. Separate bone graft fragments were bridged by newly formed woven bone. In the histological sections of 2 subjects some small islands of chondral cell differentiation were seen, which may relate to endochondral ossification. Active bone remodeling and resorption through combined osteoclastic and osteoblastic activity was present in 2 subjects (7.0 and 6.3 months post grafting), suggesting more advanced phases of graft incorporation. Mean bone volume was 68% over tissue volume (range 33

  3. Supercritical Water Reactor (SCWR) - Survey of Materials Research and Development Needs to Assess Viability

    SciTech Connect

    Philip E. MacDonald

    2003-09-01

    Supercritical water-cooled reactors (SCWRs) are among the most promising advanced nuclear systems because of their high thermal efficiency [i.e., about 45% vs. 33% of current light water reactors (LWRs)] and considerable plant simplification. SCWRs achieve this with superior thermodynamic conditions (i.e., high operating pressure and temperature), and by reducing the containment volume and eliminating the need for recirculation and jet pumps, pressurizer, steam generators, steam separators and dryers. The reference SCWR design in the U.S. is a direct cycle, thermal spectrum, light-water-cooled and moderated reactor with an operating pressure of 25 MPa and inlet/outlet coolant temperature of 280/500 °C. The inlet flow splits, partly to a down-comer and partly to a plenum at the top of the reactor pressure vessel to flow downward through the core in special water rods to the inlet plenum. This strategy is employed to provide good moderation at the top of the core, where the coolant density is only about 15-20% that of liquid water. The SCWR uses a power conversion cycle similar to that used in supercritical fossil-fired plants: high- intermediate- and low-pressure turbines are employed with one moisture-separator re-heater and up to eight feedwater heaters. The reference power is 3575 MWt, the net electric power is 1600 MWe and the thermal efficiency is 44.8%. The fuel is low-enriched uranium oxide fuel and the plant is designed primarily for base load operation. The purpose of this report is to survey existing materials for fossil, fission and fusion applications and identify the materials research and development needed to establish the SCWR viabilitya with regard to possible materials of construction. The two most significant materials related factors in going from the current LWR designs to the SCWR are the increase in outlet coolant temperature from 300 to 500 °C and the possible compatibility issues associated with the supercritical water environment.

  4. Selective chelation and extraction of lanthanides and actinides with supercritical fluids

    SciTech Connect

    Brauer, R.D.; Carleson, T.E.; Harrington, J.D.; Jean, F.; Jiang, H.; Lin, Y.; Wai, C.M.

    1994-01-01

    This report is made up of three independent papers: (1) Supercritical Fluid Extraction of Thorium and Uranium with Fluorinated Beta-Diketones and Tributyl Phosphate, (2) Supercritical Fluid Extraction of Lanthanides with Beta-Diketones and Mixed Ligands, and (3) A Group Contribution Method for Predicting the Solubility of Solid Organic Compounds in Supercritical Carbon Dioxide. Experimental data are presented demonstrating the successful extraction of thorium and uranium using fluorinated beta-diketones to form stable complexes that are extracted with supercritical carbon dioxide. The conditions for extracting the lanthanide ions from liquid and solid materials using supercritical carbon dioxide are presented. In addition, the Peng-Robison equation of state and thermodynamic equilibrium are used to predict the solubilities of organic solids in supercritical carbon dioxide from the sublimation pressure, critical properties, and a centric factor of the solid of interest.

  5. Study of Supercritical Carbon Dioxide Power Cycle for Low Grade Heat Conversion

    SciTech Connect

    Vidhi, Rachana; Goswami, Yogi D.; Chen, Huijuan; Stefanakos, Elias; Kuravi, Sarada; Sabau, Adrian S

    2011-01-01

    Research on supercritical carbon dioxide power cycles has been mainly focused on high temperature applications, such as Brayton cycle in a nuclear power plant. This paper conducts a comprehensive study on the feasibility of a CO2-based supercritical power cycle for low-grade heat conversion. Energy and exergy analyses of the cycle were conducted to discuss the obstacles as well as the potentials of using supercritical carbon dioxide as the working fluid for supercritical Rankine cycle, Carbon dioxide has desirable qualities such as low critical temperature, stability, little environmental impact and low cost. However, the low critical temperature might be a disadvantage for the condensation process. Comparison between a carbon dioxide-based supercritical Rankine cycle and an organic fluid-based supercritical Rankine cycle showed that the former needs higher pressure to achieve the same efficiency and a heat recovery system is necessary to desuperheat the turbine exhaust and pre-heat the pressure charged liquid.

  6. Towards Ultra-High Resolution Models of Climate and Weather

    SciTech Connect

    Wehner, Michael; Oliker, Leonid; Shalf, John

    2007-01-01

    We present a speculative extrapolation of the performance aspects of an atmospheric general circulation model to ultra-high resolution and describe alternative technological paths to realize integration of such a model in the relatively near future. Due to a superlinear scaling of the computational burden dictated by stability criterion, the solution of the equations of motion dominate the calculation at ultra-high resolutions. From this extrapolation, it is estimated that a credible kilometer scale atmospheric model would require at least a sustained ten petaflop computer to provide scientifically useful climate simulations. Our design study portends an alternate strategy for practical power-efficient implementations of petaflop scale systems. Embedded processor technology could be exploited to tailor a custom machine designed to ultra-high climate model specifications at relatively affordable cost and power considerations. The major conceptual changes required by a kilometer scale climate model are certain to be difficult to implement. Although the hardware, software, and algorithms are all equally critical in conducting ultra-high climate resolution studies, it is likely that the necessary petaflop computing technology will be available in advance of a credible kilometer scale climate model.

  7. Mass transfer in supercritical fluids instancing selected fluids in supercritical carbon dioxide

    NASA Astrophysics Data System (ADS)

    Hu, Miao; Benning, Rainer; Delgado, Antonio; Ertunc, Oezguer

    The research interests lie in a deeper understanding of the mechanisms of diffusion and nucle-ation of organic solutes in near-and supercritical state of a solvent, which count as important means of mass transfer in the process engineering industry. The use of supercritical fluids in industrial processes, such as extraction and particle handling, has become a more and more popular method. Take a closer look at the two processes one would find that there are obviously two sub-processes involved in each of the process, namely the diffusion/nucleation as well as a phase transition procedure. Because of the operational limitations in the practice, this phase transition can-not be neglected. So it is also included in the theoretical approach. Classically to deduce conclusions from experiment results, mathematical/physical models outlining property changes and summarizing characteristics of the two processes are expected. In order to become an insight of these phenomena from the origin, and also to serve as a fundamental attribute for the numerical simulation later, the theories of statistical thermodynamics are adopted here as a proper means to describe the behaviors of the two processes. As the diffusion coefficients of the samples in our case are only of an order of approx. 10-8m2s-1, it can be assumed that the processes are in equilibrium (local changes are neglectably small), a model can be built on a general macroscopic approach for equilibrium systems, namely the Boltzmann-Gibbs distri-bution. And some rather general methods e.g. linear response theory can be applied. But as the transfer phenomena are genuinely not equilibrium systems, from this aspect a model can also be built based on the microscopic description -the kinetic theory of the behaviors of the particles of this non-equilibrium system. The characteristics under compensated gravity are also to be considered in the models. The differences and constraints between the models are to be compared and

  8. Experimental study of choking flow of water at supercritical conditions

    NASA Astrophysics Data System (ADS)

    Muftuoglu, Altan

    Future nuclear reactors will operate at a coolant pressure close to 25 MPa and at outlet temperatures ranging from 500°C to 625°C. As a result, the outlet flow enthalpy in future Supercritical Water-Cooled Reactors (SCWR) will be much higher than those of actual ones which can increase overall nuclear plant efficiencies up to 48%. However, under such flow conditions, the thermal-hydraulic behavior of supercritical water is not fully known, e.g., pressure drop, forced convection and heat transfer deterioration, critical and blowdown flow rate, etc. Up to now, only a very limited number of studies have been performed under supercritical conditions. Moreover, these studies are conducted at conditions that are not representative of future SCWRs. In addition, existing choked flow data have been collected from experiments at atmospheric discharge pressure conditions and in most cases by using working fluids different than water which constrain researchers to analyze the data correctly. In particular, the knowledge of critical (choked) discharge of supercritical fluids is mandatory to perform nuclear reactor safety analyses and to design key mechanical components (e.g., control and safety relief valves, etc.). Hence, an experimental supercritical water facility has been built at Ecole Polytechnique de Montreal which allows researchers to perform choking flow experiments under supercritical conditions. The facility can also be used to carry out heat transfer and pressure drop experiments under supercritical conditions. In this thesis, we present the results obtained at this facility using a test section that contains a 1 mm inside diameter, 3.17 mm long orifice plate with sharp edges. Thus, 545 choking flow of water data points are obtained under supercritical conditions for flow pressures ranging from 22.1 MPa to 32.1 MPa, flow temperatures ranging from 50°C to 502°C and for discharge pressures from 0.1 MPa to 3.6 MPa. Obtained data are compared with the data given in

  9. Configuration design studies and wind tunnel tests of an energy efficient transport with a high-aspect-ratio supercritical wing

    NASA Technical Reports Server (NTRS)

    Henne, P. A.; Dahlin, J. A.; Peavey, C. C.; Gerren, D. S.

    1982-01-01

    The results of design studies and wind tunnel tests of high aspect ratio supercritical wings suitable for a medium range, narrow body transport aircraft flying near M=0.80 were presented. The basic characteristics of the wing design were derived from system studies of advanced transport aircraft where detailed structural and aerodynamic tradeoffs were used to determine the most optimum design from the standpoint of fuel usage and direct operating cost. These basic characteristics included wing area, aspect ratio, average thickness, and sweep. The detailed wing design was accomplished through application of previous test results and advanced computational transonic flow procedures. In addition to the basic wing/body development, considerable attention was directed to nacelle/plyon location effects, horizontal tail effects, and boundary layer transition effects. Results of these tests showed that the basic cruise performance objectives were met or exceeded.

  10. Ultra Efficient Engine Technology Systems Integration and Environmental Assessment

    NASA Technical Reports Server (NTRS)

    Daggett, David L.; Geiselhart, Karl A. (Technical Monitor)

    2002-01-01

    This study documents the design and analysis of four types of advanced technology commercial transport airplane configurations (small, medium large and very large) with an assumed technology readiness date of 2010. These airplane configurations were used as a platform to evaluate the design concept and installed performance of advanced technology engines being developed under the NASA Ultra Efficient Engine Technology (UEET) program. Upon installation of the UEET engines onto the UEET advanced technology airframes, the small and medium airplanes both achieved an additional 16% increase in fuel efficiency when using GE advanced turbofan engines. The large airplane achieved an 18% increase in fuel efficiency when using the P&W geared fan engine. The very large airplane (i.e. BWB), also using P&W geared fan engines, only achieved an additional 16% that was attributed to a non-optimized airplane/engine combination.

  11. Supercritical fluid reactions for coal processing. Quarterly report, July 1--September 30, 1996

    SciTech Connect

    Eckert, C.A.

    1996-12-31

    Exciting opportunities exist for the application of supercritical fluid (SCF) reactions for the pre-treatment of coal. Utilizing reactants which resemble the organic nitrogen containing components of coal, we propose to develop a method to tailor chemical reactions in supercritical fluid solvents for the specific application of coal denitrogenation. The Diels-Alder reaction of anthracene and 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) was chosen as the model system and was investigated in supercritical carbon dioxide.

  12. Supercritical fluid technology. (Latest citations from the Biobusiness database). Published Search

    SciTech Connect

    1995-12-01

    The bibliography contains citations concerning applications of supercritical fluid technology. Topics include supercritical fluid technology use in chromatographic analysis, removal of cholesterol and caffeine from food products, extraction of essential oils, extraction of pesticide and other toxic contaminants from soil and food, and food analysis. Supercritical fluid technology patents and uses in the pharmaceutical industry are also described.(Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  13. Hydraulic studies of drilling microbores with supercritical steam, nitrogen and carbon dioxide

    DOE Data Explorer

    Ken Oglesby

    2010-01-01

    Hydraulic studies of drilling microbores at various depths and with various hole sizes, tubing, fluids and rates showed theoretical feasibility. WELLFLO SIMULATIONS REPORT STEP 4: DRILLING 10,000 FT WELLS WITH SUPERCRITICAL STEAM, NITROGEN AND CARBON DIOXIDE STEP 5: DRILLING 20,000 FT WELLS WITH SUPERCRITICAL STEAM, NITROGEN AND CARBON DIOXIDE STEP 6: DRILLING 30,000 FT WELLS WITH SUPERCRITICAL STEAM, NITROGEN AND CARBON DIOXIDE Mehmet Karaaslan, MSI

  14. Rutile Solubility in Supercritical Albite-H2O fluids: Implications for Element Mobility in Subduction Zones

    NASA Astrophysics Data System (ADS)

    Antignano, A.; Manning, C. E.

    2006-12-01

    Supercritical fluids with compositions intermediate between H2O and silicate are widely invoked as important transport agents in subduction zones. This proposal is in part motivated by the expectation that such fluids might have greater ability to dissolve and transport key trace elements at high P and T. As a test of this hypothesis, we measured the solubility of rutile (TiO2) in supercritical albite (ab, NaAlSi3O8)-H2O at 900°C, 1.5 GPa, from Xab = 0 to 0.3. At this P and T, rutile has very low solubility in H2O and there is full miscibility between H2O and ab melt. Experiments were conducted in a piston-cylinder apparatus with NaCl-graphite furnaces. In each, a 1.6 mm OD Pt inner capsule with a synthetic rutile crystal was lightly crimped and placed in a 3.5 OD Pt capsule with ultra pure H2O and powdered Amelia albite. Equilibrium was achieved after 4 hrs. Solubility was determined by the weight loss of the rutile grain. Quench textures consistent with supercritical behavior were observed in all runs. Residual corundum is present in the H2O-rich runs, but it decreases with increasing ab concentration. Results show that rutile solubility initially rises sharply with increasing ab concentration from 38 ppm in pure H2O to 739 ppm at Xab =0.05 (44 wt%). With further increase in ab, rutile solubility increases only slightly, to 922 ppm at Xab =0.25 (83 wt%). No significant solubility increase was noted near the critical compositon (~50 wt% ab). Our results show that intermediate fluids do not significantly enhance Ti solubility above dilute silicate-bearing solutions. The presence of residual Al2O3 and the sharp initial rise in rutile solubility at low Xab imply that, by analogy with silicate melts, Ti is present in solution as Na-Ti-O complexes (e.g., Dickenson and Hess, 1985, GCA, 49, 2289). However, the lack of residual corundum at high Xab suggests a transiton to different Ti species, perhaps aqueous NaAlSi3O8-like complexes. Our results give insight into rutile

  15. Creation Dynamics of Bound States in Supercritical Fields

    SciTech Connect

    Krekora, P.; Cooley, K.; Su, Q.; Grobe, R.

    2005-08-12

    Using space-time resolved solutions to relativistic quantum field theory, we analyze the electron-positron creation process from vacuum in the long-time regime in which multiple pairs are produced. We find that for a supercritical potential of finite extension, the time dependence of the production rate of pairs is described by four distinct regimes that have their direct counterparts in the time evolved spatial density of the particles. These regimes include the shape-invariant birth process, an entanglement-induced reduction of interference, a recurrent Pauli suppression of pair production induced by electron-potential scattering, and finally a production halt associated with a population of supercritical and a partial population of subcritical bound states.

  16. The Supercritical Pile Model: Prompt Emission Across the Electromagnetic Spectrum

    NASA Technical Reports Server (NTRS)

    Kazanas, Demos; Mastichiadis, A.

    2008-01-01

    The "Supercritical Pile" GRB model is an economical model that provides the dissipation necessary to convert explosively the energy stored in relativistic protons in the blast wave of a GRB into radiation; at the same time it produces spectra whose luminosity peaks at 1 MeV in the lab frame, the result of the kinematics of the proton-photon - pair production reaction that effects the conversion of proton energy to radiation. We outline the fundamental notions behind the "Supercritical Pile" model and discuss the resulting spectra of the prompt emission from optical to gamma-ray energies of order Gamma^2 m_ec^2, (Gamma is the Lorentz factor of the blast wave) present even in the absence of an accelerated particle distribution and compare our results to bursts that cover this entire energy range. Particular emphasis is given on the emission at the GLAST energy range both in the prompt and the afterglow stages of the burst.

  17. Application of supercritical antisolvent method in drug encapsulation: a review

    PubMed Central

    Kalani, Mahshid; Yunus, Robiah

    2011-01-01

    The review focuses on the application of supercritical fluids as antisolvents in the pharmaceutical field and demonstrates the supercritical antisolvent method in the use of drug encapsulation. The main factors for choosing the solvent and biodegradable polymer to produce fine particles to ensure effective drug delivery are emphasized and the effect of polymer structure on drug encapsulation is illustrated. The review also demonstrates the drug release mechanism and polymeric controlled release system, and discusses the effects of the various conditions in the process, such as pressure, temperature, concentration, chemical compositions (organic solvents, drug, and biodegradable polymer), nozzle geometry, CO2 flow rate, and the liquid phase flow rate on particle size and its distribution. PMID:21796245

  18. The wavenumbers of supercritical surface-tension-driven Benard convection

    NASA Technical Reports Server (NTRS)

    Koschmieder, E. L.; Switzer, D. W.

    1992-01-01

    The cell size or the wavenumbers of supercritical hexagonal convection cells in primarily surface-tension-driven convection on a uniformly heated plate has been studied experimentally in thermal equilibrium in thin layers of silicone oil of large aspect ratio. It has been found that the cell size decreases with increased temperature difference in the slightly supercritical range, and that the cell size is unique within the experimental error. It has also been observed that the cell size reaches a minimum and begins to increase at larger temperature differences. This reversal of the rate of change of the wavenumber with temperature difference is attributed to influences of buoyancy on the fluid motion. The consequences of buoyancy have been tested with three fluid layers of different depth.

  19. Method and apparatus for waste destruction using supercritical water oxidation

    DOEpatents

    Haroldsen, Brent Lowell; Wu, Benjamin Chiau-pin

    2000-01-01

    The invention relates to an improved apparatus and method for initiating and sustaining an oxidation reaction. A hazardous waste, is introduced into a reaction zone within a pressurized containment vessel. An oxidizer, preferably hydrogen peroxide, is mixed with a carrier fluid, preferably water, and the mixture is heated until the fluid achieves supercritical conditions of temperature and pressure. The heating means comprise cartridge heaters placed in closed-end tubes extending into the center region of the pressure vessel along the reactor longitudinal axis. A cooling jacket surrounds the pressure vessel to remove excess heat at the walls. Heating and cooling the fluid mixture in this manner creates a limited reaction zone near the center of the pressure vessel by establishing a steady state density gradient in the fluid mixture which gradually forces the fluid to circulate internally. This circulation allows the fluid mixture to oscillate between supercritical and subcritical states as it is heated and cooled.

  20. Supercritical fluid carbon dioxide cleaning of plutonium parts

    SciTech Connect

    Hale, S.J.; Haschke, J.M.; Cox, L.E.

    1993-09-01

    Supercritical fluid (SCF) carbon dioxide (CO{sub 2}) is being evaluated for use as a cleaning solvent to replace 1,1,1-trichloroethane for the final cleaning of plutonium (Pu) parts. These parts must be free of organic residue to avoid corrosion in the stockpile. Thermodynamic and kinetic data for selected reactions of Pu metal are evaluated as a basis for assessing the risk of a violent exothermic reaction during the use of SCF CO{sub 2} on Pu. The need for considering kinetic behavior of a reaction in assessing its thermal risk is demonstrated. Weight difference data and results of xray photoelectron spectroscopy to evaluate the surface after exposure to the supercritical fluid show that SCF CO{sub 2} is an effective and compatible cleaning solvent.

  1. Transpiring wall supercritical water oxidation test reactor design report

    SciTech Connect

    Haroldsen, B.L.; Ariizumi, D.Y.; Mills, B.E.; Brown, B.G.; Rousar, D.C.

    1996-02-01

    Sandia National Laboratories is working with GenCorp, Aerojet and Foster Wheeler Development Corporation to develop a transpiring wall supercritical water oxidation reactor. The transpiring wall reactor promises to mitigate problems of salt deposition and corrosion by forming a protective boundary layer of pure supercritical water. A laboratory scale test reactor has been assembled to demonstrate the concept. A 1/4 scale transpiring wall reactor was designed and fabricated by Aerojet using their platelet technology. Sandia`s Engineering Evaluation Reactor serves as a test bed to supply, pressurize and heat the waste; collect, measure and analyze the effluent; and control operation of the system. This report describes the design, test capabilities, and operation of this versatile and unique test system with the transpiring wall reactor.

  2. Supercritical water oxidation data acquisition testing. Final report, Volume II

    SciTech Connect

    1996-11-01

    Supercritical Water Oxidation (SCWO) technology holds great promise for treating mixed wastes, in an environmentally safe and efficient manner. In the spring of 1994 the US Department of Energy (DOE), Idaho Operations Office awarded Stone & Webster Engineering Corporation, of Boston Massachusetts and its sub-contractor MODAR, Inc. of Natick Massachusetts a Supercritical Water Oxidation Data Acquisition Testing (SCWODAT) program. The SCWODAT program was contracted through a Cooperative Agreement that was co-funded by the US Department of Energy and the Strategic Environmental Research and Development Program. The SCWODAT testing scope outlined by the DOE in the original Cooperative Agreement and amendments thereto was initiated in June 1994 and successfully completed in December 1995. The SCWODAT program provided further information and operational data on the effectiveness of treating both simulated mixed waste and typical Navy hazardous waste using the MODAR SCWO technology.

  3. Supercritical Saltwater Spray for Marine Cloud Brightening (MCB)

    NASA Astrophysics Data System (ADS)

    Neukermans, A.; Cooper, G. F.; Foster, J.; Galbraith, L. K.; Johnston, D.; Ormond, B.; Wang, Q.

    2012-12-01

    Solar Radiation Management (SRM), including both stratospheric sulfur aerosol delivery and MCB, has emerged as the leading contender for geoengineering. Field research in MCB would require a technique capable of producing 1017 salt nuclei/sec from a single source on a seagoing vessel. Spraying supercritical saltwater has emerged as a viable technology, at least for research purposes. Under optimum conditions a single 50-μm nozzle produces 1014 suitable nuclei/sec. Power consumption is high (1-2 MW), but 95% of the required energy is in the form of heat that can probably be obtained from wasted ship-engine heat. While its implementation is conceptually simple, the corrosive nature of supercritical saltwater makes the material requirements very demanding. Progress on this work is detailed.

  4. Solute Nucleation and Growth in Supercritical Fluid Mixtures

    NASA Technical Reports Server (NTRS)

    Smedley, Gregory T.; Wilemski, Gerald; Rawlins, W. Terry; Joshi, Prakash; Oakes, David B.; Durgin, William W.

    1996-01-01

    This research effort is directed toward two primary scientific objectives: (1) to determine the gravitational effect on the measurement of nucleation and growth rates near a critical point and (2) to investigate the nucleation process in supercritical fluids to aid in the evaluation and development of existing theoretical models and practical applications. A nucleation pulse method will be employed for this investigation using a rapid expansion to a supersaturated state that is maintained for approximately 1 ms followed by a rapid recompression to a less supersaturated state that effectively terminates nucleation while permitting growth to continue. Nucleation, which occurs during the initial supersaturated state, is decoupled from growth by producing rapid pressure changes. Thermodynamic analysis, condensation modeling, apparatus design, and optical diagnostic design necessary for the initiation of a theoretical and experimental investigation of naphthalene nucleation from supercritical CO2 have been completed.

  5. Solubility of the sesquiterpene alcohol patchoulol in supercritical carbon dioxide

    PubMed Central

    Hybertson, Brooks M.

    2009-01-01

    The solubility of the sesquiterpene alcohol patchoulol in supercritical carbon dioxide was measured at P ranging from 10.0 MPa to 25.0 MPa and T of 40.0 and 50.0 °C using a simple microsampling type apparatus with a 100.5 µL sample loop to remove aliquots for off-line analysis. The system was first validated using vanillin with off-line spectrophotometric analysis, then utilized for patchoulol measurements with off-line GC-MS analysis. The measured solubility of patchoulol in supercritical CO2 ranged from mole fractions of 0.43 × 10−3 at 10.0 MPa and 50.0 °C to 9.45 × 10−3 at 25.0 MPa and 40.0 °C. PMID:19424449

  6. A study of vortex breakdown in supercritical fluids

    NASA Astrophysics Data System (ADS)

    Crook, Loren C.

    The objective of this thesis is to evaluate the hydrodynamic stability theory of vortex breakdown by examining its presence in a swirling supercritical fluid jet. Supercritical fluids were chosen because they are technologically important, and because their strong density gradients near the critical point provide a self-excitable flow regime where hydrodynamic instabilities should be more easily identified. Computations were developed to provide flow conditions for experimental observation of vortex breakdown and to estimate hydrodynamic flow instabilities prior to testing. The RANS computations of an axial-plus-tangential air swirler were developed and verified as grid-independent and in agreement with experimental results reported in the literature. The computations also produced a correlation of momentum swirl number as a function of mass ratio (tangential/total) for estimating swirl number during experiments. Finally, the computations were extended to simulate supercritical CO2 in an axial-plus-tangential swirler that was compatible with the supercritical injection facility. Three mass flow ratio cases were investigated extensively: no-swirl (0%), low-swirl prior to breakdown (25%), and moderate swirl with breakdown (45%). (The three corresponding momentum swirl numbers for these mass flow ratios were 0.0, 0.30 and 0.80.) These three cases also served as the basis for the experimental portion of the work. Swirling supercritical fluid jets were observed in the injection facility using schlieren imaging for three separate swirl numbers. The Sobel method was used to locate the jet edges. The jets were characterized by their radii, including mean and standard deviation, and spreading angles as functions of swirl number and density ratio (2.3, 2.6, and 5.0). The swirl number was identified as the dominant parameter in determining the spreading angle and jet radius. Vortex breakdown was identified as the jet structure changed from straight edges to curved, signifying

  7. Modeling of supercritical fluid extraction from herbaceous matrices

    SciTech Connect

    Reverchon, E.; Donsi, G.; Osseo, L.S. . Dipt. di Ingegneria Chimica e Alimentare)

    1993-11-01

    Experimental results of supercritical fluid extraction from various herbaceous matrices are presented. In optimal extraction conditions, the use of a fractional separation technique allows a nearly complete separation of the extract in cuticular waxes and essential oil. The modeling of these results is proposed starting from the description of the mass transfer from a single spherical particle. The simultaneous extraction of two pseudocompounds is assumed to simulate the two compound families obtained by fractionation. The model is then extended to simulate the whole extractor. The yields of essential oil and cuticular waxes obtained from rosemary, basil, and marjoram leaves are fairly simulated by the model. Intraparticle mass transfer resulted as the controlling stage in supercritical extraction of essential oils.

  8. The partial pair correlation functions of dense supercritical water

    NASA Astrophysics Data System (ADS)

    Tassaing, T.; Bellissent-Funel, M.-C.; Guillot, B.; Guissani, Y.

    1998-05-01

    Neutron diffraction measurements of heavy water and of two isotopic H2O/D2O mixtures at supercritical state (T = 380 °C and ρD2O = 0.73 g/cm3) are presented. In combining the set of neutron diffraction data with previous X-rays measurements of Yamanaka et al. (J. Chem. Phys., 101 (1994) 9830), it has been possible by using a Monte Carlo method to reach the partial pair correlation functions gOH(r), gHH(r) and gOO(r). The results are compared with molecular-dynamics simulations using the SPCE pair potential for water. These new results confirm that hydrogen bonding is still present in dense supercritical water.

  9. The wave numbers of supercritical surface tension driven Benard convection

    NASA Technical Reports Server (NTRS)

    Koschmieder, E. L.; Switzer, D. W.

    1991-01-01

    The cell size or the wave numbers of supercritical hexagonal convection cells in primarily surface tension driven convection on a uniformly heated plate was studied experimentally in thermal equilibrium in thin layers of silicone oil of large aspect ratio. It was found that the cell size decreases with increased temperature difference in the slightly supercritical range, and that the cell size is unique within the experimental error. It was also observed that the cell size reaches a minimum and begins to increase at larger temperature differences. This reversal of the rate of change of the wave number with temperature difference is attributed to influences of buoyancy on the fluid motion. The consequences of buoyancy were tested with three fluid layers of different depth.

  10. Creation dynamics of bound States in supercritical fields.

    PubMed

    Krekora, P; Cooley, K; Su, Q; Grobe, R

    2005-08-12

    Using space-time resolved solutions to relativistic quantum field theory, we analyze the electron-positron creation process from vacuum in the long-time regime in which multiple pairs are produced. We find that for a supercritical potential of finite extension, the time dependence of the production rate of pairs is described by four distinct regimes that have their direct counterparts in the time evolved spatial density of the particles. These regimes include the shape-invariant birth process, an entanglement-induced reduction of interference, a recurrent Pauli suppression of pair production induced by electron-potential scattering, and finally a production halt associated with a population of supercritical and a partial population of subcritical bound states. PMID:16196767

  11. QENS from polymeric micelles in supercritical CO2

    NASA Astrophysics Data System (ADS)

    Triolo, R.; Arrighi, V.; Triolo, A.; Migliardo, P.; Magazù, S.; McClain, J. B.; Betts, D.; DeSimone, J. M.; Middendorf, H. D.

    2000-04-01

    We report QENS measurements from PS-b-PFOA aggregates in supercritical CO2. These consist of dense cores of CO2-insoluble polystyrene surrounded by a `corona' of PFOA surfactant molecules whose CO2-philic groups interface with supercritical CO2. Lineshapes are dominated by localized diffusive modes and segmental dynamics of the anchored, finite-length PFOA chains. For Q˜0.6 Å-1, we obtain effective diffusion coefficients of ≈0.8×10-6 cm2/sec. At higher Q, a single component is not sufficient as shown by excess intensity on the flanks. For Q>1.5 Å-1, the wings reflect contributions due to a distribution of faster, more localized chain modes.

  12. Homopolymers and Micelles in Supercritical CO2 : a SANS Study

    NASA Astrophysics Data System (ADS)

    Chillura-Martino, D.; McClain, J. B.; Canelas, D.; Betts, D.; Samulski, E. T.; Desimone, J. M.; Wignall, G. D.; Londono, J. D.; Triolo, R.

    1996-03-01

    Supercritical Carbon Dioxide (SC-CO_2) is becoming an attractive alternative to the liquid solvents traditionally used as polymerization media. We have applied small-angle neutron scattering (SANS) to characterize homopolymers and micellar systems in SC-CO_2. Although polymerizations are carried out at high pressures, the penetrating power of the neutron beam means that typical cell windows are virtually transparent. Homopolymers studied include polyfluoro-octyl acrylate (PFOA), hexafluoro-polypropylene oxide and Polydimethyl-siloxane. Also, copolymers of amphiphilic character in CO_2, were characterized via SANS. Systems studied were PFOA-polystyrene diblocks and PFOA-polyethyleneoxide (PFOA-PEO) graft copolymers, which swell as the CO2 medium is saturated with water. This work illustrates the utility of SANS to measure molecular dimensions, thermodynamic variables, molecular weights, micelle structures etc. in supercritical CO_2.

  13. Pulse radiolysis studies in supercritical CO{sub 2}

    SciTech Connect

    Jonah, C. D.; Dimitrijevic, N. M.; Bartels, D. M.; Takahashi, K.

    2000-03-09

    The pulse radiolysis technique has been applied to study reactions of ions in supercritical solutions. Evidence for the formation of C{sub 2}O{sub 4}{sup +} has been found in supercritical CO{sub 2}. The rate of the electron transfer reaction from dimethyl aniline to the C{sub 2}O{sub 4}{sup +} was measured over the density range of 0.17--0.7 g/cm{sup 3}. The reaction rate was measured to be close to diffusion-controlled at the lowest density; at higher densities, the rate was considerably below the apparent diffusion-controlled rate. Similar behavior was found for the reaction of the anion (presumably C{sub 2}O{sub 4}{sup {minus}}) with benzoquinone. The reaction of O{sub 2} with C{sub 2}O{sub 4}{sup +} was considerably slower than the expected diffusion-controlled rate.

  14. Fundamental kinetics and mechanistic pathways for oxidation reactions in supercritical water

    NASA Technical Reports Server (NTRS)

    Webley, Paul A.; Tester, Jefferson W.

    1988-01-01

    Oxidation of the products of human metabolism in supercritical water has been shown to be an efficient way to accomplish the on-board water/waste recycling in future long-term space flights. Studies of the oxidation kinetics of methane to carbon dioxide in supercritical water are presented in this paper in order to enhance the fundamental understanding of the oxidation of human waste compounds in supercritical water. It is concluded that, although the elementary reaction models remain the best hope for simulating oxidation in supercritical water, several modifications to existing mechanisms need to be made to account for the role of water in the reaction mechanism.

  15. Heat Transfer Phenomena in Supercritical Water Nuclear Reactors

    SciTech Connect

    Mark H. Anderson; MichaelL. Corradini; Riccardo Bonazza; Jeremy R. Licht

    2007-10-03

    A supercritical water heat transfer facility has been built at the University of Wisconsin to study heat transfer in ancircular and square annular flow channel. A series of integral heat transfer measurements has been carried out over a wide range of heat flux, mas velocity and bulk water temperatures at a pressure of 25 MPa. The circular annular test section geometry is a 1.07 cm diameter heater rod within a 4.29 diameter flow channel.

  16. An artificial viscosity method for the design of supercritical airfoils

    NASA Technical Reports Server (NTRS)

    Mcfadden, G. B.

    1979-01-01

    A numerical technique is presented for the design of two-dimensional supercritical wing sections with low wave drag. The method is a design mode of the analysis code H which gives excellent agreement with experimental results and is widely used in the aircraft industry. Topics covered include the partial differential equations of transonic flow, the computational procedure and results; the design procedure; a convergence theorem; and description of the code.

  17. Conversion of hazardous materials using supercritical water oxidation

    DOEpatents

    Rofer, Cheryl K.; Buelow, Steven J.; Dyer, Richard B.; Wander, Joseph D.

    1992-01-01

    A process for destruction of hazardous materials in a medium of supercritical water without the addition of an oxidant material. The harzardous material is converted to simple compounds which are relatively benign or easily treatable to yield materials which can be discharged into the environment. Treatment agents may be added to the reactants in order to bind certain materials, such as chlorine, in the form of salts or to otherwise facilitate the destruction reactions.

  18. Droplet turbulence interactions under subcritical and supercritical conditions

    NASA Technical Reports Server (NTRS)

    Coy, E. B.; Greenfield, S. C.; Ondas, M. S.; Song, Y.-H.; Spegar, T. D.; Santavicca, D. A.

    1993-01-01

    The goal of this research is to experimentally characterize the behavior of droplets in vaporizing liquid sprays under conditions typical of those encountered in high pressure combustion systems such as liquid fueled rocket engines. Of particular interest are measurements of droplet drag, droplet heating, droplet vaporization, droplet distortion, and secondary droplet breakup, under both subcritical and supercritical conditions. The paper presents a brief description of the specific accomplishments which have been made over the past year.

  19. Valorization of horse manure through catalytic supercritical water gasification.

    PubMed

    Nanda, Sonil; Dalai, Ajay K; Gökalp, Iskender; Kozinski, Janusz A

    2016-06-01

    The organic wastes such as lignocellulosic biomass, municipal solid waste, sewage sludge and livestock manure have attracted attention as alternative sources of energy. Cattle manure, a waste generated in surplus amounts from the feedlot, has always been a chief environmental concern. This study is focused on identifying the candidacy of horse manure as a next generation feedstock for biofuel production through supercritical water gasification. The horse manure was gasified in supercritical water to examine the effects of temperature (400-600°C), biomass-to-water ratio (1:5 and 1:10) and reaction time (15-45min) at a pressure range of 23-25MPa. The horse manure and resulting biochar were characterized through carbon-hydrogen-nitrogen-sulfur (CHNS), inductively coupled plasma-mass spectrometry (ICP-MS), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM). The effects of alkali catalysts such as NaOH, Na2CO3 and K2CO3 at variable concentrations (1-2wt%) were investigated to maximize the hydrogen yields. Supercritical water gasification of horse manure with 2wt% Na2CO3 at 600°C and 1:10 biomass-to-water ratio for 45min revealed maximum hydrogen yields (5.31mmol/g), total gas yields (20.8mmol/g) with greater carbon conversion efficiency (43.1%) and enhanced lower heating value of gas products (2920kJ/Nm(3)). The manure-derived biochars generated at temperatures higher than 500°C also demonstrated higher thermal stability (weight loss <34%) and larger carbon content (>70wt%) suggesting their application in enhancing soil fertility and carbon sequestration. The results propose that supercritical water gasification could be a proficient remediation technology for horse manure to generate hydrogen-rich gas products. PMID:27067100

  20. Supercritical Fluid Assisted Synthesis and Processing of Carbon Nanotubes

    SciTech Connect

    Ye, Sufang; Wu, Fengming; Ye, Xiangrong; Lin, Yuehe

    2009-03-26

    Carbon nanotubes (CNTs) constitute one of the most fascinating nanomaterials with specific properties and enormous applications. Taking advantages of the unique properties of supercritical fluids (SCFs), various techniques have been developed to produce and process CNTs and related nanostructured materials when conventional techniques become unviable. Herein we propose a critical review of these SCF based techniques. The most relevant characteristics of each technique and the enabled novel structures and functions which are difficult to accomplish by traditional techniques are highlighted.

  1. Supercritical carbon dioxide: a solvent like no other

    PubMed Central

    Peach, Jocelyn

    2014-01-01

    Summary Supercritical carbon dioxide (scCO2) could be one aspect of a significant and necessary movement towards green chemistry, being a potential replacement for volatile organic compounds (VOCs). Unfortunately, carbon dioxide has a notoriously poor solubilising power and is famously difficult to handle. This review examines attempts and breakthroughs in enhancing the physicochemical properties of carbon dioxide, focusing primarily on factors that impact solubility of polar and ionic species and attempts to enhance scCO2 viscosity. PMID:25246947

  2. Carbon dioxide-based supercritical fluids as IC manufacturing solvents

    SciTech Connect

    Rubin, J.B.; Davenhall, L.B.; Taylor, C.M.V.; Sivils, L.D.; Pierce, T.; Tiefert, K.

    1999-05-11

    The production of integrated circuits (IC's) involves a number of discrete steps which utilize hazardous or regulated solvents and generate large waste streams. ES&H considerations associated with these chemicals have prompted a search for alternative, more environmentally benign solvent systems. An emerging technology for conventional solvent replacement is the use of supercritical fluids based on carbon dioxide (CO{sub 2}). Research work, conducted at Los Alamos in conjunction with the Hewlett-Packard Company, has lead to the development of a CO{sub 2}-based supercritical fluid treatment system for the stripping of hard-baked photoresists. This treatment system, known as Supercritical CO{sub 2} Resist Remover, or CORR, uses a two-component solvent composed of a nonhazardous, non-regulated compound, dissolved in supercritical CO{sub 2}. The solvent/treatment system has been successfully tested on metallized Si wafers coated with negative and positive photoresist, the latter both before and after ion-implantation. A description of the experimental data will be presented. Based on the initial laboratory results, the project has progressed to the design and construction of prototype, single-wafer photoresist-stripping equipment. The integrated system involves a closed-loop, recirculating cycle which continuously cleans and regenerates the CO{sub 2}, recycles the dissolved solvent, and separates and concentrates the spent resist. The status of the current design and implementation strategy of a treatment system to existing IC fabrication facilities will be discussed. Additional remarks will be made on the use of a SCORR-type system for the cleaning of wafers prior to processing.

  3. Ultrasound enhanced process for extracting metal species in supercritical fluids

    DOEpatents

    Wai, Chien M.; Enokida, Youichi

    2006-10-31

    Improved methods for the extraction or dissolution of metals, metalloids or their oxides, especially lanthanides, actinides, uranium or their oxides, into supercritical solvents containing an extractant are disclosed. The disclosed embodiments specifically include enhancing the extraction or dissolution efficiency with ultrasound. The present methods allow the direct, efficient dissolution of UO2 or other uranium oxides without generating any waste stream or by-products.

  4. Solubilities of phenazopyridine, propranolol, and methimazole in supercritical carbon dioxide.

    PubMed

    Yamini, Yadollah; Arab, Jaber; Asghari-Khiavi, Mehdi

    2003-04-24

    The equilibrium solubilities of three drugs (phenazopyridine, propranolol and methimazole) were determined at temperatures ranging from 308 to 348 K and pressures from 122 to 355 bar in supercritical CO2 by a simple and reliable static method. The crossover region was observed for phenazopyridine, propranolol and methimazole at 180 bar. The solubilities were correlated using a semi empirical model. Correlation of the results shows good self-consistency of the data obtained. PMID:12852461

  5. Wettability of supercritical carbon dioxide/water/quartz systems: simultaneous measurement of contact angle and interfacial tension at reservoir conditions.

    PubMed

    Saraji, Soheil; Goual, Lamia; Piri, Mohammad; Plancher, Henry

    2013-06-11

    Injection of carbon dioxide in deep saline aquifers is considered as a method of carbon sequestration. The efficiency of this process is dependent on the fluid-fluid and rock-fluid interactions inside the porous media. For instance, the final storage capacity and total amount of capillary-trapped CO2 inside an aquifer are affected by the interfacial tension between the fluids and the contact angle between the fluids and the rock mineral surface. A thorough study of these parameters and their variations with temperature and pressure will provide a better understanding of the carbon sequestration process and thus improve predictions of the sequestration efficiency. In this study, the controversial concept of wettability alteration of quartz surfaces in the presence of supercritical carbon dioxide (sc-CO2) was investigated. A novel apparatus for measuring interfacial tension and contact angle at high temperatures and pressures based on Axisymmetric Drop Shape Analysis with no-Apex (ADSA-NA) method was developed and validated with a simple system. Densities, interfacial tensions, and dynamic contact angles of CO2/water/quartz systems were determined for a wide range of pressures and temperatures relevant to geological sequestration of CO2 in the subcritical and supercritical states. Image analysis was performed with ADSA-NA method that allows the determination of both interfacial tensions and contact angles with high accuracy. The results show that supercritical CO2 alters the wettability of quartz surface toward less water-wet conditions compared to subcritical CO2. Also we observed an increase in the water advancing contact angles with increasing temperature indicating less water-wet quartz surfaces at higher temperatures. PMID:23627310

  6. Experimental Study on Fluid Distribution at Ultra-High Metamorphic Conditions

    NASA Astrophysics Data System (ADS)

    Mönicke, K.; Burchard, M.; Duyster, J.; Maresch, W. V.; Röller, K.; Stöckhert, B.

    2001-12-01

    Ultra-high pressure (UHP) metamorphic rocks record deep subduction of continental crust. Insight into their rheological behavior at UHP metamorphic conditions is important for the understanding of the mechanical state and the kinematics within subduction zones. Amazingly, many exhumed UHP metamorphic rocks do not show evidence of significant deformation. Thus, it has been proposed that deformation is localized in low-strength zones controlled by partially wetting interstitial fluids [1]. Experimental results [2] show that at UHP metamorphic conditions only one homogenous fluid phase with variable composition exists, whose density and viscosity should be intermediate between those of conventional aqueous solutions and hydrous melts. Inclusions of such supercritical fluid have been recently described from a natural UHP metamorphic rock [3]. Motivated by these findings, experiments using a piston-cylinder apparatus were performed to study the fluid distribution in various rock types at pressures of 3.5 GPa and temperatures between 900 ° C and 600 ° C. Starting materials were natural UHP metamorphic specimens of (1) S-type granitic biotite-phengite-gneiss and (2) pyrope-quartzite, both from the Dora Maira Massif (Western Alps, Italy) and (3) a diamond-bearing garnet-mica-gneiss with granodioritic bulk composition from the Saxonian Erzgebirge (Germany), all with 2 wt.% water added. The supercritical fluids formed in these experiments can be quenched to form a silicic glass with demixing of an aqueous solution without changing the UHP fluid topology significantly. The shape of the fluid-filled interstices is irregular and complex, resulting in a low volume/interface area ratio and a potential of high stress concentration at the edges of wedge-shaped offshoots. We propose that the distribution of supercritical fluids has a pronounced effect on the strength of cool subducted crust, allowing deformation by grain boundary sliding and dissolution precipitation creep, or

  7. Dehydrating and Sterilizing Wastes Using Supercritical CO2

    NASA Technical Reports Server (NTRS)

    Brown, Ian J.

    2006-01-01

    A relatively low-temperature process for dehydrating and sterilizing biohazardous wastes in an enclosed life-support system exploits (1) the superior mass-transport properties of supercritical fluids in general and (2) the demonstrated sterilizing property of supercritical CO2 in particular. The wastes to be treated are placed in a chamber. Liquid CO2, drawn from storage at a pressure of 850 psi (approx.=5.9 MPa) and temperature of 0 C, is compressed to pressure of 2 kpsi (approx.=14 MPa) and made to flow into the chamber. The compression raises the temperature to 10 C. The chamber and its contents are then further heated to 40 C, putting the CO2 into a supercritical state, in which it kills microorganisms in the chamber. Carrying dissolved water, the CO2 leaves the chamber through a back-pressure regulator, through which it is expanded back to the storage pressure. The expanded CO2 is refrigerated to extract the dissolved water as ice, and is then returned to the storage tank at 0 C

  8. Process for treating effluent from a supercritical water oxidation reactor

    SciTech Connect

    Barnes, C.M.; Shapiro, C.

    1995-12-31

    The present invention relates generally to a method for treating and recycling the effluent from a supercritical water oxidation reactor and more specifically to a method for treating and recycling the effluent by expanding the effluent without extensive cooling. Supercritical water oxidation is the oxidation of fuel, generally waste material, in a body of water under conditions above the thermodynamic critical point of water. The current state of the art in supercritical water oxidation plant effluent treatment is to cool the reactor effluent through heat exchangers or direct quench, separate the cooled liquid into a gas/vapor stream and a liquid/solid stream, expand the separated effluent, and perform additional purification on gaseous, liquid, brine and solid effluent. If acid gases are present, corrosion is likely to occur in the coolers. During expansion, part of the condensed water will revaporize. Vaporization can damage the valves due to cavitation and erosion. The present invention expands the effluent stream without condensing the stream. Radionuclides and suspended solids are more efficiently separated in the vapor phase. By preventing condensation, the acids are kept in the much less corrosive gaseous phase thereby limiting the damage to treatment equipment. The present invention also reduces the external energy consumption, by utilizing the expansion step to also cool the effluent.

  9. Supercritical nitrogen processing for the purification of reactive porous materials.

    PubMed

    Stadie, Nicholas P; Callini, Elsa; Mauron, Philippe; Borgschulte, Andreas; Züttel, Andreas

    2015-01-01

    Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. Herein, nitrogen is presented as a novel supercritical drying fluid for specialized applications such as in the processing of reactive porous materials, where carbon dioxide and other fluids are not appropriate due to their higher chemical reactivity. Nitrogen exhibits similar physical properties in the near-critical region of its phase diagram as compared to carbon dioxide: a widely tunable density up to ~1 g ml(-1), modest critical pressure (3.4 MPa), and small molecular diameter of ~3.6 Å. The key to achieving a high solvation power of nitrogen is to apply a processing temperature in the range of 80-150 K, where the density of nitrogen is an order of magnitude higher than at similar pressures near ambient temperature. The detailed solvation properties of nitrogen, and especially its selectivity, across a wide range of common target species of extraction still require further investigation. Herein we describe a protocol for the supercritical nitrogen processing of porous magnesium borohydride. PMID:26066492

  10. Specific extraction of chromium(VI) using supercritical fluid extraction.

    PubMed

    Foy, G P; Pacey, G E

    2000-02-01

    In some situations, it is no longer sufficient to give a total concentration of a metal. Instead, what is required to understand the potential toxicity of a sample is the concentration of metal species or oxidation state. When developing species specific methods, the major concern is that the integrity of the species ratio is not changed. In other words, the sample preparation or the analytical method will not convert metal ions from one oxidation state to another. Normal extraction techniques and chromatography methods have shown some tendencies to change species ratios. An ideal extraction method would extract the metal efficiently while retaining the metal's oxidation state. The properties of supercritical fluids should approach the ideal of retention of oxidation states. For example, the need for speciation of chromium is obvious since Cr(III) is considered an essential element while Cr(VI) is thought to be toxic and carcinogenic. This paper presents the results of a species specific extraction of Cr(VI) using two different carbamate derivatives as the chelator. Supercritical fluid extraction (SFE) coupled with a fluorinated dithiocarbamate and a methanol modifier allows extraction of 1 ppm Cr(VI) from a solid matrix with a recovery level of 88.4+/-2.57% using the NIST standard sample. The optimized conditions using the HP 7680 supercritical fluid extractor were: 0.1 ml of methanol, 0.05 ml of pure water, and 0.01 g of chelate via a saturation chamber. PMID:18967865

  11. Acetic acid oxidation and hydrolysis in supercritical water

    SciTech Connect

    Meyer, J.C.; Marrone, P.A.; Tester, J.W.

    1995-09-01

    Acetic acid (CH{sub 3}COOH) hydrolysis and oxidation in supercritical water were examined from 425--600 C and 246 bar at reactor residence times of 4.4 to 9.8 s. Over the range of conditions studied, acetic acid oxidation was globally 0.72 {+-} 0.15 order in acetic acid and 0.27 {+-} 0.15 order in oxygen to a 95% confidence level, with an activation energy of 168 {+-} 21 kJ/mol, a preexponential factor of 10{sup 9.9{+-}1.7}, and an induction time of about 1.5 s at 525 C. Isothermal kinetic measurements at 550 C over the range 160 to 263 bar indicated that pressure or density did not affect the rate of acetic acid oxidation as much as was previously observed in the oxidation of hydrogen or carbon monoxide in supercritical water. Major products of acetic acid oxidation in supercritical water are carbon dioxide, carbon monoxide, methane, and hydrogen. Trace amounts of propenoic acid were occasionally detected. Hydrolysis or hydrothermolysis in the absence of oxygen resulted in approximately 35% conversion of acetic acid at 600 C, 246 bar, and 8-s reactor residence time. Regression of the limited hydrolysis runs assuming a reaction rate first-order in organic gave a global rate expression with a preexponential factor of 10{sup 4.4{+-}1.1} and an activation energy of 94 {+-} 17 kJ/mol.

  12. Fluid dynamic effects on precision cleaning with supercritical fluids

    SciTech Connect

    Phelps, M.R.; Hogan, M.O.; Silva, L.J.

    1994-06-01

    Pacific Northwest Laboratory staff have assembled a small supercritical fluids parts cleaning test stand to characterize how system dynamics affect the efficacy of precision cleaning with supercritical carbon dioxide. A soiled stainless steel coupon, loaded into a ``Berty`` autoclave, was used to investigate how changes in system turbulence and solvent temperature influenced the removal of test dopants. A pulsed laser beam through a fiber optic was used to investigate real-time contaminant removal. Test data show that cleaning efficiency is a function of system agitation, solvent density, and temperature. These data also show that high levels of cleaning efficiency can generally be achieved with high levels of system agitation at relatively low solvent densities and temperatures. Agitation levels, temperatures, and densities needed for optimal cleaning are largely contaminant dependent. Using proper system conditions, the levels of cleanliness achieved with supercritical carbon dioxide compare favorably with conventional precision cleaning methods. Additional research is currently being conducted to generalize the relationship between cleaning performance and parameters such as contaminant solubilities, mass transfer rates, and solvent agitation. These correlations can be used to optimize cleaning performance, system design, and time and energy consumption for particular parts cleaning applications.

  13. Supercritical Fluid Extraction of Plutonium and Americium from Soil

    SciTech Connect

    Fox, R.V.; Mincher, B.J.

    2002-05-23

    Supercritical fluid extraction (SFE) of plutonium and americium from soil was successfully demonstrated using supercritical fluid carbon dioxide solvent augmented with organophosphorus and beta-diketone complexants. Spiked Idaho soils were chemically and radiologically characterized, then extracted with supercritical fluid carbon dioxide at 2,900 psi and 65 C containing varying concentrations of tributyl phosphate (TBP) and thenoyltrifluoroacetone (TTA). A single 45 minute SFE with 2.7 mol% TBP and 3.2 mol% TTA provided as much as 88% {+-} 6.0 extraction of americium and 69% {+-} 5.0 extraction of plutonium. Use of 5.3 mol% TBP with 6.8 mol% of the more acidic beta-diketone hexafluoroacetylacetone (HFA) provided 95% {+-} 3.0 extraction of americium and 83% {+-} 5.0 extraction of plutonium in a single 45 minute SFE at 3,750 psi and 95 C. Sequential chemical extraction techniques were used to chemically characterize soil partitioning of plutonium and americium in pre-SFE soil samples. Sequential chemical extraction techniques demonstrated that spiked plutonium resides primarily (76.6%) in the sesquioxide fraction with minor amounts being absorbed by the oxidizable fraction (10.6%) and residual fractions (12.8%). Post-SFE soils subjected to sequential chemical extraction characterization demonstrated that 97% of the oxidizable, 78% of the sesquioxide and 80% of the residual plutonium could be removed using SFE. These preliminary results show that SFE may be an effective solvent extraction technique for removal of actinide contaminants from soil.

  14. Kinetic behaviour in supercritical fluid chromatography with modified mobile phase for 5 μm particle size and varied flow rates.

    PubMed

    Lesellier, E; Fougere, L; Poe, Donald P

    2011-04-15

    After much development of stationary phase chemistry, in recent years the focus of many studies in HPLC has shifted to increase the efficiency and analysis speed. Ultra high pressure liquid chromatography (UHPLC) using sub-2 μm particles, and high temperature liquid chromatography (HTLC), using temperatures above 100°C have received much attention. These new approaches allow the use of flow rates higher than those classically used in HPLC, reducing the analysis duration. Due to the low viscosity of supercritical fluids, high velocities, i.e. high flow rates, can be achieved with classical pumping systems typically used in supercritical fluid chromatography (SFC). The effects of the flow rate increase with CO(2)/methanol mobile phase was studied on the inlet pressure, t(0), the retention factor of the compounds, and on the efficiency. Simple comparisons of efficiencies obtained at varied temperature between SFC and HPLC, with a packed column containing 5 μm particles, show the greater kinetic performances achieved with the CO(2)/methanol fluid, and underline specific behaviours of SFC, occurring for high flow rates and sub-ambient temperature. Some values (N/t(0)) are also compared to UHPLC data, showing that good performance can be achieved in SFC without applying drastic analytical conditions. Finally, simple kinetic plots (t(0) vs N) at constant column length are used to select combinations of temperature and flow rate necessary to achieve a required theoretical plate number. PMID:21232748

  15. High-resolution x-ray tomography imaging of supercritical CO2: Investigating capillary trapping under reservoir conditions and addressing wettability alteration

    NASA Astrophysics Data System (ADS)

    Andersson, L.; Herring, A. L.; Newell, D. L.; Carey, B.; Wildenschild, D.

    2013-12-01

    In geological carbon sequestration, CO2 is stored in a supercritical state in subsurface reservoirs. Deep saline aquifers are particularly attractive because of their abundance and potentially large storage volumes. Despite very broad research efforts there are still substantial uncertainties related to the effectiveness of the trapping processes controlling the permanent storage of CO2. After injection of CO2 the saline water (brine) will imbibe back and reoccupy the pore space as the buoyant CO2 moves upwards. Some of the CO2 will remain behind in a trapping mechanism known as capillary trapping that occurs as CO2 bubbles are isolated by the brine inside some of the pore space. The large-scale movement of the trapped CO2 within the brine is thereby prevented. Capillary trapping thus constitutes an important storage mechanism following CO2 injection until subsequent aqueous dissolution and precipitation of carbonate minerals depletes the reservoir of free-phase CO2. We present pressure-saturation curves derived from drainage and imbibition experiments with brine and supercritical CO2 at 1200 PSI and at 36°C for Bentheimer sandstone cores. We compare the supercritical CO2 experiments with ambient pressure and temperature experiments using water and air (supercritical CO2 proxy fluid) for Bentheimer sandstone. The pressure-saturation curves are accompanied with quantitative results on non-wetting phase saturation, topology and connectivity as determined from three-dimensional (3D) images. The 3D data with a resolution of 4.65 μm were derived from high-resolution synchrotron x-ray computed micro-tomography (CMT), collected at the GSECARS beam line 13-BM-D at the Advanced Photon Source, Argonne National Laboratory. Drainage and imbibition experiments, performed under ambient pressure and temperature conditions, indicate that the topology of the non-wetting phase after drainage correlates with the final trapping of the non-wetting phase, after imbibition. Pressure

  16. Ultra-efficient Engine Diameter Study

    NASA Technical Reports Server (NTRS)

    Daggett, David L.; Brown, Stephen T.; Kawai, Ron T.

    2003-01-01

    Engine fan diameter and Bypass Ratio (BPR) optimization studies have been conducted since the beginning of the turbofan age with the recognition that reducing the engine core jet velocity and increasing fan mass flow rate generally increases propulsive efficiency. However, performance tradeoffs limit the amount of fan flow achievable without reducing airplane efficiency. This study identifies the optimum engine fan diameter and BPR, given the advanced Ultra-Efficient Engine Technology (UEET) powerplant efficiencies, for use on an advanced subsonic airframe. Engine diameter studies have historically focused on specific engine size options, and were limited by existing technology and transportation infrastructure (e.g., ability to fit bare engines through aircraft doors and into cargo holds). This study is unique in defining the optimum fan diameter and drivers for future 2015 (UEET) powerplants while not limiting engine fan diameter by external constraints. This report follows on to a study identifying the system integration issues of UEET engines. This Engine Diameter study was managed by Boeing Phantom Works, Seattle, Washington through the NASA Glenn Revolutionary Aero Space Engine Research (RASER) contract under task order 10. Boeing Phantom Works, Huntington Beach, completed the engine/airplane sizing optimization, while the Boeing Commercial Airplane group (BCA) provided design oversight. A separate subcontract to support the overall project was issued to Tuskegee University.

  17. Blended polymer materials extractable with supercritical carbon dioxide

    NASA Astrophysics Data System (ADS)

    Cai, Mei

    Supercritical carbon dioxide is drawing more and more attention because of its unique solvent properties along with being environmentally friendly. Historically most of the commercial interests of supercritical carbon dioxide extraction are in the food industry, pharmaceutical industry, environmental preservation and polymer processing. Recently attention has shifted from the extraction of relatively simple molecules to more complex systems with a much broader range of physical and chemical transformations. However the available data show that a lot of commercially valuable substances are not soluble in supercritical carbon dioxide due to their polar structures. This fact really limits the application of SCF extraction technology to much broader industrial applications. Therefore, the study of a polymer's solubility in a given supercritical fluid and its thermodynamic behavior becomes one of the most important research topics. The major objective of this dissertation is to develop a convenient and economic way to enhance the polymer's solubility in supercritical carbon dioxide. Further objective is to innovate a new process of making metal casting parts with blended polymer materials developed in this study. The key technique developed in this study to change a polymer's solubility in SCF CO2 is to thermally blend a commercially available and CO2 non-soluble polymer material with a low molecular weight CO2 soluble organic chemical that acts as a co-solute. The mixture yields a plastic material that can be completely solubilized in SCF CO2 over a range of temperatures and pressures. It also exhibits a variety of physical properties (strength, hardness, viscosity, etc.) depending on variations in the mixture ratio. The three organic chemicals investigated as CO2 soluble materials are diphenyl carbonate, naphthalene, and benzophenone. Two commercial polymers, polyethylene glycol and polystyrene, have been investigated as CO2 non-soluble materials. The chemical

  18. Development of supercritical fluid extraction and supercritical fluid chromatography purification methods using rapid solubility screening with multiple solubility chambers.

    PubMed

    Gahm, Kyung H; Huang, Ke; Barnhart, Wesley W; Goetzinger, Wolfgang

    2011-01-01

    Rapid solubility screening in diverse supercritical fluids (SCFs) was carried out via multiple solubility chambers with a trapping device and online ultraviolet (UV) detection. With this device, it was possible to rapidly study the solubility variations of multiple components in a mixture. Results from solubility studies have been used to develop efficient supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) methods. After the investigation of solubilities of theophylline and caffeine in several neat organic solvents and SCFs, advantages of SFE over conventional organic solvent extraction were demonstrated with a model mixture of theophylline and caffeine. The highest solubility ratio of 1:40 (theophylline:caffeine) was observed in the SCF with 20% acetonitrile (MeCN), where a ratio of 1:11 was the highest in the neat organic solvents. A model mixture of theophylline:caffeine (85:15 w/w, caffeine as an impurity) was successfully purified by SFE by leveraging the highest solubility difference. The SCF with 20% MeCN selectively removed caffeine and left theophylline largely intact. Rapid SCF solubility screening was applied to development of SFE and SFC methods in a drug discovery environment. Two successful applications were demonstrated with proprietary Amgen compounds to either remove an achiral impurity before chiral purification or enhance chiral chromatographic throughput. PMID:21766341

  19. Control system options and strategies for supercritical CO2 cycles.

    SciTech Connect

    Moisseytsev, A.; Kulesza, K. P.; Sienicki, J. J.; Nuclear Engineering Division; Oregon State Univ.

    2009-06-18

    The Supercritical Carbon Dioxide (S-CO{sub 2}) Brayton Cycle is a promising alternative to Rankine steam cycle and recuperated gas Brayton cycle energy converters for use with Sodium-Cooled Fast Reactors (SFRs), Lead-Cooled Fast Reactors (LFRs), as well as other advanced reactor concepts. The S-CO{sub 2} Brayton Cycle offers higher plant efficiencies than Rankine or recuperated gas Brayton cycles operating at the same liquid metal reactor core outlet temperatures as well as reduced costs or size of key components especially the turbomachinery. A new Plant Dynamics Computer Code has been developed at Argonne National Laboratory for simulation of a S-CO{sub 2} Brayton Cycle energy converter coupled to an autonomous load following liquid metal-cooled fast reactor. The Plant Dynamics code has been applied to investigate the effectiveness of a control strategy for the S-CO{sub 2} Brayton Cycle for the STAR-LM 181 MWe (400 MWt) Lead-Cooled Fast Reactor. The strategy, which involves a combination of control mechanisms, is found to be effective for controlling the S-CO{sub 2} Brayton Cycle over the complete operating range from 0 to 100 % load for a representative set of transient load changes. While the system dynamic analysis of control strategy performance for STARLM is carried out for a S-CO{sub 2} Brayton Cycle energy converter incorporating an axial flow turbine and compressors, investigations of the S-CO{sub 2} Brayton Cycle have identified benefits from the use of centrifugal compressors which offer a wider operating range, greater stability near the critical point, and potentially further cost reductions due to fewer stages than axial flow compressors. Models have been developed at Argonne for the conceptual design and performance analysis of centrifugal compressors for use in the SCO{sub 2} Brayton Cycle. Steady state calculations demonstrate the wider operating range of centrifugal compressors versus axial compressors installed in a S-CO{sub 2} Brayton Cycle as

  20. Liquid Behavior at Critical and Supercritical Conditions

    NASA Technical Reports Server (NTRS)

    Chiu, Huei-Huang; Gross, Klaus W.

    1989-01-01

    At a JANNAF workshop, the issue of fluids at and above the critical point was discussed to obtain a better understanding of similar conditions in combustion chambers of rocket engines. Invited experts from academic, industrial, and government institutions presented the most recent physical, numerical, and experimental advances. During the final discussion period, it was agreed that: (1) no analytical capability exists to simulate subject conditions; (2) mechanisms reflected by opalescence, the solubility of gases, other interfacial phenomena listed, and fluorescence diagnostics are new and important; (3) multicomponent mixtures, radiation, critical fluctuation, and other recorded ones pose unknown effects; and (4) various identified analytical and experimental actions must be initiated in a mutually supporting sequence.