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Sample records for multistage fluid bed

  1. Distributor for multistage fluidized beds

    SciTech Connect

    Wormser, A.

    1992-06-16

    This patent describes a multibed fluidized bed system. It comprises a fluidized bed vessel having a casing surrounding a first distributor and a second distributor downstream from the first distributor; a first bed material placed on the first distributor and a second bed material placed on the second distributor; each of the bed materials having an angle of repose; and wherein the angle formed by the substantially straight elongated tubular passages and the upper surface is less than the angle of repose of the second bed material.

  2. A multistage model of hospital bed requirements.

    PubMed Central

    Pendergast, J F; Vogel, W B

    1988-01-01

    This article presents a model for projecting future hospital bed requirements, based on clinical judgment and basic probability theory. Clinical judgment is used to define various categories of care, including a category for patients who are inappropriately hospitalized, for a large teaching hospital with a heavy indigent and psychiatric workload. Survey results and discharge abstract data are then used to calculate expected discharges and patient days for each clinical category. These expected discharges and patient days are converted into estimated bed requirements using a simple deterministic equation. Results of this multistage model are compared with the results obtained from exercising the simple deterministic equation alone. Because the multistage model removes patients from the hospital if they are deemed inappropriately placed, this model results in the projection of 5.1 percent fewer hospital beds than the simple deterministic equation alone. PMID:3403276

  3. The development of an integrated multistaged fluid bed retorting process. Technical report, October 1, 1992--December 31, 1992

    SciTech Connect

    Taulbee, D.; Fei, Y.; Carter, S.

    1993-01-01

    The KENTORT II process includes integral fluidized bed zones for pyrolysis, gasification, and combustion of the oil shale. The purpose of this program is to design and test the KENTORT II process at the 50-lb/hr scale. Along with the major activity of assembling the components of the 50-lb/hr retort, work was also completed in other areas this quarter. Basic studies of the cracking and coking kinetics of model compounds in a fixed bed reactor were continued. Additionally, as part of the effort to investigate niche market applications for KENTORT II-derived products, a study of the synthesis of carbon fibers from the heavy fraction of KENTORT II shale oil was initiated.

  4. The development of an integrated multistaged fluid-bed retorting process. Final report, September 1990--August 1994

    SciTech Connect

    Carter, S.D.; Taulbee, D.N.; Stehn, J.L.; Vego, A.; Robl, T.L.

    1995-02-01

    This summarizes the development of the KENTORT II retorting process, which includes integral fluidized bed zones for pyrolysis, gasification, and combustion of oil shale. Purpose was to design and test the process at the 50-lb/hr scale. The program included bench- scale studies of coking and cracking reactions of shale oil vapors over processed shale particles to address issues of scaleup associated with solid-recycle retorting. The bench-scale studies showed that higher amounts of carbon coverage reduce the rate of subsequent carbon deposition by shale oil vapors onto processed shale particles; however carbon-covered materials were also active in terms of cracking and coking. Main focus was the 50-lb/hr KENTORT II PDU. Cold-flow modeling and shakedown were done before the PDU was made ready for operation. Seven mass-balanced, steady-state runs were completed within the window of design operating conditions. Goals were achieved: shale feedrate, run duration (10 hr), shale recirculation rates (4:1 to pyrolyzer and 10:1 to combustor), bed temperatures (pyrolyzer 530{degree}C, gasifier 750{degree}C, combustor 830{degree}C), and general operating stability. Highest oil yields (up to 109% of Fischer assay) were achieved for runs lasting {ge} 10 hours. High C content of the solids used for heat transfer to the pyrolysis zone contributed to the enhanced oil yield achieved.

  5. Fluid bed material transfer method

    DOEpatents

    Pinske, Jr., Edward E.

    1994-01-01

    A fluidized bed apparatus comprising a pair of separated fluid bed enclosures, each enclosing a fluid bed carried on an air distributor plate supplied with fluidizing air from below the plate. At least one equalizing duct extending through sidewalls of both fluid bed enclosures and flexibly engaged therewith to communicate the fluid beds with each other. The equalizing duct being surrounded by insulation which is in turn encased by an outer duct having expansion means and being fixed between the sidewalls of the fluid bed enclosures.

  6. Multistage fluidized bed reactor performance characterization for adsorption of carbon dioxide

    SciTech Connect

    Roy, S.; Mohanty, C.R.; Meikap, B.C.

    2009-12-15

    Carbon dioxide and its different compounds are generated as primary greenhouse gases from the flue gases of coal-fired thermal power plants, boilers, and other stationary combustion processes. This greenhouse gas causes global warming after being emitted to the environment. To deal with this problem, a new dry scrubbing process was tested in this study. A three-stage countercurrent fluidized bed adsorber was developed, designed, and fabricated. It was used as a removal apparatus and operated in a continuous regime for the two-phase system. The height of each stage was 0.30 m, and the inner diameter was 0.10 m. The paper presents the removal of CO{sub 2} from gas mixtures by chemical sorption on porous granular calcium oxide particles in the reactor at ambient temperature. The advantages of a multistage fluidized bed reactor for high mass transfer and high gas-solid contact can enhance the removal of the gas when using a dry method. The effects of the operating parameters such as sorbent, superficial gas velocity, and the Weir height on CO{sub 2} removal efficiency in the multistage fluidized bed were investigated. The results indicate that the removal efficiency of the carbon dioxide was around 71% at a high solid flow rate corresponding to lower gas velocity at room temperature. In comparison with wet scrubbers, this dry process appears to have lower cost, less complicated configuration, and simpler disposal of used sorbent. The results in this study assume importance from the perspective of use of a multistage fluidized bed adsorber for control of gaseous pollutants at high temperature.

  7. Burning coal refuse in fluid beds

    SciTech Connect

    Kleinau, J.H.; Sneyd, R.J.; Lombardi, C.E.

    1985-01-01

    This paper deals with the application of fluid bed combustion technology to the burning of coal-mining waste. The designs of two stage fluid bed combustors/dryers are demonstrated as useful in the drying of coal, slag and coke, using coal and coal refuse (gob) as fuel. Anthracite mining refuse (culm) is more than abundant in Northeastern Pennsylvania. After demonstration at Shamokin, Pennsylvania, a full commercial-sized fluid bed boiler using culm is used for district heating in Wilkes-Barre, Pennsylvania. Limited research work has shown the utility of using fine coal as filter aid in sludge incineration. With the rising avenues of the suitability of coal as auxiliary fuel in fluid bed sludge incineration, an expansion of these concepts combines the use of coal or coal refuse as filter aid and auxiliary fuel. Limestone addition controls SO/sub 2/ emission.

  8. Removal of CO2 in a multistage fluidized bed reactor by diethanol amine impregnated activated carbon.

    PubMed

    Das, Dipa; Samal, Debi Prasad; Meikap, Bhim C

    2016-07-28

    To mitigate the emission of carbon dioxide (CO2), we have developed and designed a four-stage fluidized bed reactor. There is a counter current exchange between solid adsorbent and gas flow. In this present investigation diethanol amine (DEA) impregnated activated carbon made from green coconut shell was used as adsorbent. This type of adsorbent not only adsorbs CO2 due to the presence of pore but also chemically reacts with CO2 and form secondary zwitterions. Sampling and analysis of CO2 was performed using Orsat apparatus. The effect of initial CO2 concentration, gas velocity, solid rate, weir height etc. on removal efficiency of CO2 have been investigated and presented. The percentage removal of CO2 has been found close to 80% under low gas flow rate (0.188 m/s), high solid flow rate (4.12 kg/h) and weir height of 50 mm. From this result it has been found out that multistage fluidized bed reactor may be a suitable equipment for removal of CO2 from flue gas. PMID:27163861

  9. Rigging Test Bed Development for Validation of Multi-Stage Decelerator Extractions

    NASA Technical Reports Server (NTRS)

    Kenig, Sivan J.; Gallon, John C.; Adams, Douglas S.; Rivellini, Tommaso P.

    2013-01-01

    The Low Density Supersonic Decelerator project is developing new decelerator systems for Mars entry which would include testing with a Supersonic Flight Dynamics Test Vehicle. One of the decelerator systems being developed is a large supersonic ringsail parachute. Due to the configuration of the vehicle it is not possible to deploy the parachute with a mortar which would be the preferred method for a spacecraft in a supersonic flow. Alternatively, a multi-stage extraction process using a ballute as a pilot is being developed for the test vehicle. The Rigging Test Bed is a test venue being constructed to perform verification and validation of this extraction process. The test bed consists of a long pneumatic piston device capable of providing a constant force simulating the ballute drag force during the extraction events. The extraction tests will take place both inside a high-bay for frequent tests of individual extraction stages and outdoors using a mobile hydraulic crane for complete deployment tests from initial pack pull out to canopy extraction. These tests will measure line tensions and use photogrammetry to track motion of the elements involved. The resulting data will be used to verify packing and rigging as well, as validate models and identify potential failure modes in order to finalize the design of the extraction system.

  10. Dry coating in a rotary fluid bed.

    PubMed

    Kablitz, Caroline Désirée; Harder, Kim; Urbanetz, Nora Anne

    2006-02-01

    A highly efficient dry coating process was developed to obtain an enteric film avoiding completely the use of organic solvents and water. Using hydroxypropyl methylcellulose acetate succinate (HPMCAS) an enteric coat should be obtained without adding talc as anti-tacking agent because of problems arising from microbiological contamination. Further on, a method was developed preparing isolated films in order to determine the glass transition temperature (T(g)) and the required process temperature. The process was conducted in the rotary fluid bed with a gravimetric powder feeder achieving an exact dosage in contrast to volumetric powder feeder. A three way nozzle was aligned tangential to the pellet bed movement feeding simultaneously powder and plasticizer into the rotary fluid bed. The determined coating efficiency of the talc-free formulation was high with 94% and storage stability regarding tacking could be achieved using colloidal silicium dioxide as top powder. The T(g) of the enteric coat could be determined analyzing the T(g) of isolated films obtained by coating celluloid spheres instead of pellets using the dry coating process in rotary fluid bed. The dry coating process has been demonstrated to be a serious alternative to conventional solvent or water based coating processes. PMID:16290285

  11. Reducing mode circulating fluid bed combustion

    DOEpatents

    Lin, Yung-Yi; Sadhukhan, Pasupati; Fraley, Lowell D.; Hsiao, Keh-Hsien

    1986-01-01

    A method for combustion of sulfur-containing fuel in a circulating fluid bed combustion system wherein the fuel is burned in a primary combustion zone under reducing conditions and sulfur captured as alkaline sulfide. The reducing gas formed is oxidized to combustion gas which is then separated from solids containing alkaline sulfide. The separated solids are then oxidized and recycled to the primary combustion zone.

  12. Removal of hazardous gaseous pollutants from industrial flue gases by a novel multi-stage fluidized bed desulfurizer.

    PubMed

    Mohanty, C R; Adapala, Sivaji; Meikap, B C

    2009-06-15

    Sulfur dioxide and other sulfur compounds are generated as primary pollutants from the major industries such as sulfuric acid plants, cupper smelters, catalytic cracking units, etc. and cause acid rain. To remove the SO(2) from waste flue gas a three-stage counter-current multi-stage fluidized bed adsorber was developed as desulfurization equipment and operated in continuous bubbling fluidization regime for the two-phase system. This paper represents the desulfurization of gas mixtures by chemical sorption of sulfur dioxide on porous granular calcium oxide particles in the reactor at ambient temperature. The advantages of the multi-stage fluidized bed reactor are of high mass transfer and high gas-solid residence time that can enhance the removal of acid gas at low temperature by dry method. Experiments were carried out in the bubbling fluidization regime supported by visual observation. The effects of the operating parameters such as sorbent (lime) flow rate, superficial gas velocity, and the weir height on SO(2) removal efficiency in the multistage fluidized bed are reported. The results have indicated that the removal efficiency of the sulfur dioxide was found to be 65% at high solid flow rate (2.0 kg/h) corresponding to lower gas velocity (0.265 m/s), wier height of 70 mm and SO(2) concentration of 500 ppm at room temperature. PMID:19036509

  13. Study of ebullated bed fluid dynamics

    NASA Astrophysics Data System (ADS)

    Schaefer, R. J.; Rundell, D. N.; Shou, J. K.

    1983-07-01

    The fluid dynamics occurring in a coal liquefaction reactor is measured and compared with cold flow fluidization results. Catalyst bed expansions and gas holdups are higher in the Process Development Unit (PDU) than those observed in the cold flow tests for slurries having the same nominal viscosity. Comparison of PDU results with cold flow results shows that the bulk of the operating reactor gas flow lies in the ideal bubbly regime. Existence of churn turbulent behavior during these two experiments is consistent with trends observed in earlier cold flow experiments. Two and three phase fluidization experiments are carried out. Bed expansion is primarily a function of slurry velocity, with gas velocity having only a weak effect. A viscometer is adapted for measurement of the viscosity of coal slurries at high temperature and pressure. A significant degree of backmixing occurs in the H-Coal system.

  14. A design methodology for a magnetorheological fluid damper based on a multi-stage radial flow mode

    NASA Astrophysics Data System (ADS)

    Liao, C. R.; Zhao, D. X.; Xie, L.; Liu, Q.

    2012-08-01

    In this paper, a magnetorheological (MR) fluid damper based on a multi-stage radial flow mode is put forward, compared with traditional ones with annular damping channel which are of low magnetic field utilization and high energy consumption. The equivalent magnetic circuit model is derived, along with the relation between the magnetic induction at the working gap and the exciting current in the field coils. The finite-element software ANYSY is used to analyze the distribution of the magnetic field in the MR valve. The flow differential equation for a MR fluid in radial flow is theoretically set up, and the numerical solution is validated by means of the Herschel-Bulkley constitutive model. A MR damper was designed and fabricated in Chongqing University in accordance with the technical requirements of a railway vehicle anti-yaw damper, and the force-displacement characteristic of the damper was tested with J95-I type shock absorber test-bed. The results show that the experimental damping forces are in good agreement with the analytical ones, and the methodology is believed to help predict the damping force of a MR damper.

  15. Fluid bed solids heater. Final technical report

    SciTech Connect

    Preuit, L. C.

    1980-01-01

    A solids heater which operates at up to 2000 F was designed, fabricated, installed and operated through checkout at the Morgantown Energy Technology Center at Morgantown, West Virginia. The system, designated the 2000 F Fluid Bed Solids Heater (FBSH) uses a fluidized bed to heat limestone to 600 F and aluminium oxide or silicon carbide to 2000 F and discharges heated solids upon demand. The FBSH with added valve handling and pressurization equipment is known as the Valve Hot Solids Test Unit and is intended for use by the US Department of Energy for testing of valves for severe service applications in coal conversion and utilization processes. The FBSH as designed and supplied by Combustion Power Company includes process equipment, controls, the enclosing building and other associated equipment. In the 600 F range of operation it can circulate limestone through two valve test trains simultaneously on a continuous basis. Only one valve test train is used for 2000 F solids and operation in that range is also continuous. Limestone, crushed to minus 5/16 size, is heated, discharged, and recycled at a maximum average rate of 250 lb/min while aluminum oxide or silicon carbide, No. 8 grit, is circulated at rates up to 167 lb/min. The FBSH control system is designed for automatic operation, and capability is included for external computerized data acquisition and/or supervisory control. An operating and maintenance manual and as-built drawings have been submitted. This report describes the FBSH equipment, its design basis, and its operation. It has been prepared and submitted in fulfillment of Contract Number DIAC05-77ET10499.

  16. Evaluation of fluid bed heat exchanger optimization parameters. Final report

    SciTech Connect

    Not Available

    1980-03-01

    Uncertainty in the relationship of specific bed material properties to gas-side heat transfer in fluidized beds has inhibited the search for optimum bed materials and has led to over-conservative assumptions in the design of fluid bed heat exchangers. An experimental program was carried out to isolate the effects of particle density, thermal conductivity, and heat capacitance upon fluid bed heat transfer. A total of 31 tests were run with 18 different bed material loads on 12 material types; particle size variations were tested on several material types. The conceptual design of a fluidized bed evaporator unit was completed for a diesel exhaust heat recovery system. The evaporator heat transfer surface area was substantially reduced while the physical dimensions of the unit increased. Despite the overall increase in unit size, the overall cost was reduced. A study of relative economics associated with bed material selection was conducted. For the fluidized bed evaporator, it was found that zircon sand was the best choice among materials tested in this program, and that the selection of bed material substantially influences the overall system costs. The optimized fluid bed heat exchanger has an estimated cost 19% below a fin augmented tubular heat exchanger; 31% below a commercial design fluid bed heat exchanger; and 50% below a conventional plain tube heat exchanger. The comparisons being made for a 9.6 x 10/sup 6/ Btu/h waste heat boiler. The fluidized bed approach potentially has other advantages such as resistance to fouling. It is recommended that a study be conducted to develop a systematic selection of bed materials for fluidized bed heat exchanger applications, based upon findings of the study reported herein.

  17. Regulation of electrolyte and fluid metabolism in multi-stage ultra-marathoners.

    PubMed

    Knechtle, B; Knechtle, P; Rüst, C A; Gnädinger, M; Imoberdorf, R; Kohler, G; Rosemann, T; Ballmer, P

    2012-11-01

    The purposes of this study were (i) to determine the prevalence of exercise-associated hyponatremia (EAH) in multi-stage ultra-marathoners and (ii) to gain more insight into fluid and electrolyte regulation during a multi-stage race. Body mass, sodium concentration ([Na⁺]), potassium concentration ([K⁺]), creatinine, urea, specific gravity, and osmolality in urine were measured in 25 male ultra-marathoners in the 'Swiss Jura Marathon' 2008 with 11,000 m gain of altitude over 7 stages covering 350 km, before and after each stage. Haemoglobin, haematocrit, creatinine, urea, [Na⁺], [K⁺], and osmolality were measured in plasma before stage 1 and after stages 1, 3, 5, and 7. Two athletes (8%) showed plasma [Na⁺] <135 mmol/l. Body mass, plasma [Na⁺], and plasma [K⁺] remained unchanged (p>0.05). Urine specific gravity (p<0.001) and osmolality in both plasma (p<0.01) and urine (p<0.001) were increased and haematocrit (p<0.0001), haemoglobin (p<0.0001) and plasma albumin were decreased (p<0.001). Plasma volume (p<0.01) and plasma urea (p<0.001) were increased. The K⁺/Na⁺ ratio in urine increased >1.0 after each stage and returned to <1.0 the morning of the next stage (p<0.001). To summarize, more sodium than potassium was excreted during rest. The increased urinary sodium losses during rest are compatible with the syndrome of inappropriate secretion of antidiuretic hormone (SIADH) or the cerebral salt-wasting syndrome (CSWS). Further studies are needed to determine the antidiuretic hormone (ADH) and both the atrial natriuretic peptide (ANP) and the brain natriuretic peptide (BNP) during multi-stage races. PMID:22638835

  18. Large Scale Tests on Jointed and Bedded Rocks Under Multi-Stage Triaxial Compression and Direct Shear

    NASA Astrophysics Data System (ADS)

    Vergara, Maximiliano R.; Kudella, Peter; Triantafyllidis, Theodoros

    2015-01-01

    The mechanical behavior of bedded and jointed rock was examined in the context of the design of slopes, tunnels and tunnel portals along a planned new rail line. To obtain representative properties for describing the mechanical behavior of this material, large scale triaxial tests were performed. Specimens with a size of 60 cm diameter and 120 cm height composed of sandstone and claystone beds were tested in triaxial compression using a multi-stage technique. The specimens showed a ductile behavior for the stress regime tested. The strength parameters were calculated according to the Mohr-Coulomb failure criterion. The axial and volumetric deformations were measured and the viscosity of the composite rock material was assessed by deformation rate alterations. For some specimens, direct shear tests were conducted in samples containing joints. The results of the tests show that the failure of the bedded specimens was given by the combined failure of both materials. This was confirmed by a numerical model including rock discontinuities.

  19. INVESTIGATION OF FLUID BED COMBUSTION OF MUNICIPAL SOLID WASTE

    EPA Science Inventory

    An experimental study was undertaken to burn processed municipal solid waste in a fluid-bed combustor containing water-cooled tubes in the bed. The 300-hour test was performed without incident and terminated on schedule. The combustor and ducting were clean on inspection after th...

  20. Fluid-bed air-supply system

    DOEpatents

    Zielinski, Edward A.; Comparato, Joseph R.

    1979-01-01

    The air-supply system for a fluidized-bed furnace includes two air conduits for the same combustion zone. The conduits feed separate sets of holes in a distributor plate through which fluidizing air flows to reach the bed. During normal operation, only one conduit and set of holes is used, but the second conduit and set of holes is employed during start-up.

  1. Shielded fluid stream injector for particle bed reactor

    SciTech Connect

    Notestein, J.E.

    1991-12-31

    A shielded fluid-stream injector assembly is provided for particle bed reactors. The assembly includes a perforated pipe injector disposed across the particle bed region of the reactor and an inverted V-shaped shield placed over the pipe, overlapping it to prevent descending particles from coming into direct contact with the pipe. The pipe and shield are fixedly secured at one end to the reactor wall and slidably secured at the other end to compensate for thermal expansion. An axially extending housing aligned with the pipe and outside the reactor and an inline reamer are provided for removing deposits from the inside of the pipe. The assembly enables fluid streams to be injected and distributed uniformly into the particle bed with minimized clogging of injector ports. The same design may also be used for extraction of fluid streams from particle bed reactors.

  2. Shielded fluid stream injector for particle bed reactor

    DOEpatents

    Notestein, John E.

    1993-01-01

    A shielded fluid-stream injector assembly is provided for particle bed reactors. The assembly includes a perforated pipe injector disposed across the particle bed region of the reactor and an inverted V-shaped shield placed over the pipe, overlapping it to prevent descending particles from coming into direct contact with the pipe. The pipe and shield are fixedly secured at one end to the reactor wall and slidably secured at the other end to compensate for thermal expansion. An axially extending housing aligned with the pipe and outside the reactor and an in-line reamer are provided for removing deposits from the inside of the pipe. The assembly enables fluid streams to be injected and distributed uniformly into the particle bed with minimized clogging of injector ports. The same design may also be used for extraction of fluid streams from particle bed reactors.

  3. Fluid bed technology in materials processing

    SciTech Connect

    Gupta, C.K.; Sathiyamoorthy, D.

    1999-01-01

    The author explores the various aspects of fluidization engineering and examines its applications in a multitude of materials processing techniques. Topics include process metallurgy, fluidization in nuclear engineering, and the pros and cons of various fluidization equipment. Gupta emphasizes fluidization engineering in high temperature processing, and high temperature fluidized bed furnaces.

  4. Bed inventory overturn in a circulating fluid bed riser with pant-leg structure

    SciTech Connect

    Jinjing Li; Wei Wang; Hairui Yang; Junfu Lv; Guangxi Yue

    2009-05-15

    The special phenomenon, nominated as bed inventory overturn, in circulating fluid bed (CFB) riser with pant-leg structure was studied with model calculation and experimental work. A compounded pressure drop mathematic model was developed and validated with the experimental data in a cold experimental test rig. The model calculation results agree well with the measured data. In addition, the intensity of bed inventory overturn is directly proportional to the fluidizing velocity and is inversely proportional to the branch point height. The results in the present study provide significant information for the design and operation of a CFB boiler with pant-leg structure. 15 refs., 10 figs., 1 tab.

  5. EVALUATION AND DEMONSTRATION OF THE CHEMICALLY ACTIVE FLUID BED

    EPA Science Inventory

    The report gives results of the operation of a 17-MW Chemically Active Fluid Bed (CAFB) demonstration unit, retrofitted to a natural gas boiler. The CAFB process gasifies high-sulfur, high-metals-content liquid and solid fuels. Residual oil, lignite, and bituminous coal were gasi...

  6. Computational fluid dynamic modeling of fluidized-bed polymerization reactors

    SciTech Connect

    Rokkam, Ram

    2012-01-01

    Polyethylene is one of the most widely used plastics, and over 60 million tons are produced worldwide every year. Polyethylene is obtained by the catalytic polymerization of ethylene in gas and liquid phase reactors. The gas phase processes are more advantageous, and use fluidized-bed reactors for production of polyethylene. Since they operate so close to the melting point of the polymer, agglomeration is an operational concern in all slurry and gas polymerization processes. Electrostatics and hot spot formation are the main factors that contribute to agglomeration in gas-phase processes. Electrostatic charges in gas phase polymerization fluidized bed reactors are known to influence the bed hydrodynamics, particle elutriation, bubble size, bubble shape etc. Accumulation of electrostatic charges in the fluidized-bed can lead to operational issues. In this work a first-principles electrostatic model is developed and coupled with a multi-fluid computational fluid dynamic (CFD) model to understand the effect of electrostatics on the dynamics of a fluidized-bed. The multi-fluid CFD model for gas-particle flow is based on the kinetic theory of granular flows closures. The electrostatic model is developed based on a fixed, size-dependent charge for each type of particle (catalyst, polymer, polymer fines) phase. The combined CFD model is first verified using simple test cases, validated with experiments and applied to a pilot-scale polymerization fluidized-bed reactor. The CFD model reproduced qualitative trends in particle segregation and entrainment due to electrostatic charges observed in experiments. For the scale up of fluidized bed reactor, filtered models are developed and implemented on pilot scale reactor.

  7. Coal fired fluid bed module for a single elevation style fluid bed power plant

    DOEpatents

    Waryasz, Richard E.

    1979-01-01

    A fluidized bed for the burning of pulverized fuel having a specific waterwall arrangement that comprises a structurally reinforced framework of wall tubes. The wall tubes are reversely bent from opposite sides and then bonded together to form tie rods that extend across the bed to support the lateral walls thereof.

  8. Method for enhancing the desulfurization of hot coal gas in a fluid-bed coal gasifier

    DOEpatents

    Grindley, Thomas

    1989-01-01

    A process and apparatus for providing additional desulfurization of the hot gas produced in a fluid-bed coal gasifier, within the gasifier. A fluid-bed of iron oxide is located inside the gasifier above the gasification bed in a fluid-bed coal gasifier in which in-bed desulfurization by lime/limestone takes place. The product gases leave the gasification bed typically at 1600.degree. to 1800.degree. F. and are partially quenched with water to 1000.degree. to 1200.degree. F. before entering the iron oxide bed. The iron oxide bed provides additional desulfurization beyond that provided by the lime/limestone.

  9. METC Fluid-bed Test Rigs/Test Program

    SciTech Connect

    Walczak, S.C.; Rockey, J.M.; Rutten, J.

    1993-09-01

    Since its last runs in December 1989, the 6-inch gasifier has been modified to enlarge the reactor inside diameter to 10 inches. Recent runs have shown stable operation and increased carbon conversion with the new gasifier size. As a 10-inch reactor, the METC FBG has logged over 150 hours online with Montana Rosebud coal. Table 2 shows typical solids analyses for an April 1993 run. A series of hot gas desulfurization tests using a batch-mode, fluidized bed to contact the coal gas with sulfur capturing sorbent marked the last integrated runs with the 6-inch, fluid-bed gasifier [2]. Table 3 shows typical coal gas composition before and after the fluid-bed, hot gas desulfurization reactor. Shakedown tests of the MGCR were performed in April and May 1993. These tests were performed primarily to obtain the characteristics of a candle filter created by the Shell Development Company as part of a Cooperative Research and Development Agreement (CRADA). The April run was a 4-day test using a 30-lb batch of zinc ferrite desulfurization sorbent. A plot of the sulfur removal in this run compared with one in 1989 [3] is shown in Figure 5. It is obvious from this figure that the MGCR has performed consistently despite a 4-year hiatus.

  10. Bed-rest studies: Fluid and electrolyte responses

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.

    1983-01-01

    Confinement in the horizontal position for 2 to 3 weeks results in a chronic decrease in plasma volume, increased interstitial fluid volume, and unchanged or slightly increased extracellular fluid volume. Concentrations of blood electrolytes, glucose, and nitrogenous constituents remain within normal limits of variability when maintenance levels of isometric or isotonic exercise are performed for 1 hr/day. Hematocrit and plasma osmolality can be elevated significantly throughout bed rest (BR). Significant diuresis occurs on the first day, and increases in urine Na and Ca continue throughout BR, although voluntary fluid intake is unchanged. Urine Na and K are evaluated during the second week of BR in spite of stabilization of PV and extracellular volume. The initial diuresis probably arises from the extracellular fluid while subsequent urine loss above control levels must come from the intracellular fluid. Preservation of the extracellular volume takes precedance over maintenance of the intracellular fluid volume. The functioning of a natriuretic factor (hormone) to account for the continued increased loss of Na in the urine is suggested.

  11. Bed-rest studies - Fluid and electrolyte responses

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.

    1983-01-01

    Confinement in the horizontal position for 2 to 3 weeks results in a chronic decrease in plasma volume, increased interstitial fluid volume, and unchanged or slightly increased extracellular fluid volume. Concentrations of blood electrolytes, glucose, and nitrogenous constituents remain within normal limits of variability when maintenance levels of isometric or isotonic exercise are performed for 1 hr/day. Hematocrit and plasma osmolality can be elevated significantly throughout bed rest (BR). Significant diuresis occurs on the first day, and increases in urine Na and Ca continue throughout BR, although voluntary fluid intake is unchanged. Urine Na and K are evaluated during the second week of BR in spite of stabilization of PV and extracellular volume. The initial diuresis probably arises from extracellular fluid while subsequent urine loss above control levels must come from the intracellular fluid. Preservation of the extracellular volume takes precedance over maintenance of the intracellular fluid volume. The functioning of a natriuretic factor (hormone) to account for the continued increased loss of Na in the urine is suggested. Previously announced in STAR as N83-24160

  12. CFD analysis of fluid flow in an axial multi-stage partial-admission ORC turbine

    NASA Astrophysics Data System (ADS)

    Surwilo, Jan; Lampart, Piotr; Szymaniak, Mariusz

    2015-10-01

    Basic operational advantages of the Organic Rankine Cycle (ORC) systems and specific issues of turbines working in these systems are discussed. The strategy for CFD simulation of the considered ORC turbine and the main issues of the numerical model are presented. The method of constructing the 3D CAD geometry as well as discretisation of the flow domain are also shown. Main features of partial admission flow in the multi-stage axial turbine are discussed. The influence of partial admission on the working conditions of the subsequent stage supplied at the full circumference is also described.

  13. Granular bed emission control of a fluid-bed bark combustor

    SciTech Connect

    Tollett, R.M.; Turchina, A.V.; Ostendorf, R.G.; Navratil, L.G.

    1985-01-01

    Various additive mixtures were evaluated for effects on modifying resistivity of aspen bark ash. This had a direct effect on the efficiency of the Electroscrubber Filter (ESF) which is an electrically enhanced granular bed filter. Increased efficiencies were demonstrated in full scale testing at the Procter and Gamble plant in Green Bay, Wisconsin. Since July, 1984, emission tests have shown results below 0.04 number/MM BTU. The ESF was installed in 1983 on an EPI fluid-bed combuster burning aspen bark. In the first year of operation the ESF had trouble maintaining grid voltage. As with electrostatic precipitators, Electroscrubbers are sensitive to the resistivity of the ash collected but in an opposite way. Low resistivity is good for an electrostatic precipitator (ESP), but bad for an Electroscrubber. This paper discusses the importance of resistivity and the theoretical aspects of an Electroscrubber type of device.

  14. Relationship between fluid bed aerosol generator operation and the aerosol produced

    SciTech Connect

    Carpenter, R.L.; Yerkes, K.

    1980-12-01

    The relationships between bed operation in a fluid bed aerosol generator and aerosol output were studied. A two-inch diameter fluid bed aerosol generator (FBG) was constructed using stainless steel powder as a fluidizing medium. Fly ash from coal combustion was aerosolized and the influence of FBG operating parameters on aerosol mass median aerodynamic diameter (MMAD), geometric standard deviation (sigma/sub g/) and concentration was examined. In an effort to extend observations on large fluid beds to small beds using fine bed particles, minimum fluidizing velocities and elutriation constant were computed. Although FBG minimum fluidizing velocity agreed well with calculations, FBG elutriation constant did not. The results of this study show that the properties of aerosols produced by a FBG depend on fluid bed height and air flow through the bed after the minimum fluidizing velocity is exceeded.

  15. Computational Fluid Dynamics Simulation of Fluidized Bed Polymerization Reactors

    SciTech Connect

    Rong Fan

    2006-08-09

    Fluidized beds (FB) reactors are widely used in the polymerization industry due to their superior heat- and mass-transfer characteristics. Nevertheless, problems associated with local overheating of polymer particles and excessive agglomeration leading to FB reactors defluidization still persist and limit the range of operating temperatures that can be safely achieved in plant-scale reactors. Many people have been worked on the modeling of FB polymerization reactors, and quite a few models are available in the open literature, such as the well-mixed model developed by McAuley, Talbot, and Harris (1994), the constant bubble size model (Choi and Ray, 1985) and the heterogeneous three phase model (Fernandes and Lona, 2002). Most these research works focus on the kinetic aspects, but from industrial viewpoint, the behavior of FB reactors should be modeled by considering the particle and fluid dynamics in the reactor. Computational fluid dynamics (CFD) is a powerful tool for understanding the effect of fluid dynamics on chemical reactor performance. For single-phase flows, CFD models for turbulent reacting flows are now well understood and routinely applied to investigate complex flows with detailed chemistry. For multiphase flows, the state-of-the-art in CFD models is changing rapidly and it is now possible to predict reasonably well the flow characteristics of gas-solid FB reactors with mono-dispersed, non-cohesive solids. This thesis is organized into seven chapters. In Chapter 2, an overview of fluidized bed polymerization reactors is given, and a simplified two-site kinetic mechanism are discussed. Some basic theories used in our work are given in detail in Chapter 3. First, the governing equations and other constitutive equations for the multi-fluid model are summarized, and the kinetic theory for describing the solid stress tensor is discussed. The detailed derivation of DQMOM for the population balance equation is given as the second section. In this section

  16. Factorial tests on process operating conditions and bed fines on the circulating fluid bed performance

    SciTech Connect

    Shadle, L.J.; Spenik, James; Sarra, Angela; Ontko, J.S.

    2004-07-21

    A cold-flow circulating fluid bed (CFB) was operated using coke breeze with a packed-bed standpipe over a range of riser and standpipe air flows. The bed materials were selected to simulate solids flow in a CFB gasifier (carbonizer) but are generally relevant to most CFB processes. CFB tests were conducted primarily in the transport mode with sufficient gas velocity to achieve a uniform axial riser pressure profiles over most of the riser height. The independent variables tested included the riser gas velocity, aeration at the base of the standpipe, and concentration of fines (average particle size). The solids inventory and riser outlet pressure were maintained constant. Factorial tests were conducted in randomized order and in duplicate to provide and an unbiased estimate of the error. Fines were tested as a blocked variable. The gas velocity, standpipe aeration, and relative amount of fine particles were all found to be significant factors affecting both the riser solids holdup and solids flux. The riser pressure drop and mass circulation increased at the higher level of fines contrary to some earlier reports in the literature. The riser pressure drop was fitted using the general linear model (GLM), which explained more than 98% of the variation within the data, while a GLM for the mass circulation rate explained over 90%. The uncertainty of process operating variables was characterized independently through a series of duplicated flow proving experiments.

  17. Computational fluid dynamics modeling of coal gasification in a pressurized spout-fluid bed

    SciTech Connect

    Zhongyi Deng; Rui Xiao; Baosheng Jin; He Huang; Laihong Shen; Qilei Song; Qianjun Li

    2008-05-15

    Computational fluid dynamics (CFD) modeling, which has recently proven to be an effective means of analysis and optimization of energy-conversion processes, has been extended to coal gasification in this paper. A 3D mathematical model has been developed to simulate the coal gasification process in a pressurized spout-fluid bed. This CFD model is composed of gas-solid hydrodynamics, coal pyrolysis, char gasification, and gas phase reaction submodels. The rates of heterogeneous reactions are determined by combining Arrhenius rate and diffusion rate. The homogeneous reactions of gas phase can be treated as secondary reactions. A comparison of the calculated and experimental data shows that most gasification performance parameters can be predicted accurately. This good agreement indicates that CFD modeling can be used for complex fluidized beds coal gasification processes. 37 refs., 7 figs., 5 tabs.

  18. Multistage structural evolution in simple monatomic supercritical fluids: superstable tetrahedral local order.

    PubMed

    Ryltsev, R E; Chtchelkatchev, N M

    2013-11-01

    The local order units of dense simple liquid are typically three-dimensional (close packed) clusters: hcp, fcc, and icosahedrons. We show that the fluid demonstrates the superstable tetrahedral local order up to temperatures several orders of magnitude higher than the melting temperature and down to critical density. While the solid-like local order (hcp, fcc) disappears in the fluid at much lower temperatures and far above critical density. We conclude that the supercritical fluid shows the temperature (density)-driven two-stage "melting" of the three-dimensional local order. We also find that the structure relaxation times in the supercritical fluid are much larger than ones estimated for weakly interactive gas even far above the melting line. PMID:24329208

  19. Computational fluid dynamics analysis of aerosol deposition in pebble beds

    NASA Astrophysics Data System (ADS)

    Mkhosi, Margaret Msongi

    2007-12-01

    The Pebble Bed Modular Reactor is a high temperature gas cooled reactor which uses helium gas as a coolant. The reactor uses spherical graphite pebbles as fuel. The fuel design is inherently resistant to the release of the radioactive material up to high temperatures; therefore, the plant can withstand a broad spectrum of accidents with limited release of radionuclides to the environment. Despite safety features of the concepts, these reactors still contain large inventories of radioactive materials. The transport of most of the radioactive materials in an accident occurs in the form of aerosol particles. In this dissertation, the limits of applicability of existing computational fluid dynamics code FLUENT to the prediction of aerosol transport have been explored. The code was run using the Reynolds Averaged Navier-Stokes turbulence models to determine the effects of different turbulence models on the prediction of aerosol particle deposition. Analyses were performed for up to three unit cells in the orthorhombic configuration. For low flow conditions representing natural circulation driven flow, the laminar flow model was used and the results were compared with existing experimental data for packed beds. The results compares well with experimental data in the low flow regime. For conditions corresponding to normal operating of the reactor, analyses were performed using the standard k-ɛ turbulence model. From the inertial deposition results, a correlation that can be used to estimate the deposition of aerosol particles within pebble beds given inlet flow conditions has been developed. These results were converted into a dimensionless form as a function of a modified Stokes number. Based on results obtained in the laminar regime and for individual pebbles, the correlation developed for the inertial impaction component of deposition is believed to be credible. The form of the correlation developed also allows these results to be applied to pebble beds of different

  20. Northwest Africa 5738: Multistage fluid-driven secondary alteration in an extraordinarily evolved eucrite

    NASA Astrophysics Data System (ADS)

    Warren, Paul H.; Rubin, Alan E.; Isa, Junko; Gessler, Nicholas; Ahn, Insu; Choi, Byeon-Gak

    2014-09-01

    The Northwest Africa 5738 eucrite contains a record of unprecedented geochemical complexity for a sample from the HED asteroid. It originated with a uniquely evolved (Stannern Trend) primary igneous composition, combining ultra-high bulk incompatible element and Na2O concentrations with a relatively low mg. Its bulk oxygen-isotopic composition (Δ‧17O = -0.27‰), as well as its trace element composition (e.g., Ga/Al), confirm other evidence for classification as a eucrite. Pyroxene mg equilibration, exsolution and “cloudy” inclusions, all reflect a typical eucritic degree of thermal metamorphism. The rock contains an unprecedented array of microscopic fluid-metasomatic vein deposits. Most common are curvy microveins within pyroxene, which consist dominantly of Ca-plagioclase (typically An95, in stark contrast with the rock’s An68-78 primary-igneous plagioclase), with Fe-olivine (Fo14) and Cr-spinel as additional major constituents. Likely related to these microveins are small masses of intergrown Ca-plagioclase (again roughly An95) and silica (or high-Si glass). Analyses of the microvein Cr-spinels show stoichiometry implying a significant Fe3+ content (Fe2O3 0.7-2.3 wt.%), and fO2 up to roughly IW+3; clearly elevated in comparison to the normal HED fO2 of about IW-1. The fO2 results show an anticorrelation with equilibration T (and with Mg/Fe), which suggests the parent fluid system became more oxidizing as it cooled. NWA 5738 also contains apparent secondary iron metal. The Fe-metals are very pure, with Ni consistently below an EPMA detection limit of ∼0.01 wt.%. The vein-like shapes of roughly 1/3 of the largest Fe-metals suggest origin by deposition from a fluid. The role of pyroxene exsolution as template for a denticular (sawtooth) Fe-metal edge shape, and the survival of Fo14 olivine in a rock with abundant silica and a far higher bulk mg, suggest that the most intense thermal metamorphism occurred no later than the secondary alteration. Near

  1. Method and apparatus for enhancing the desulfurization of hot coal gas in a fluid-bed coal gasifier

    DOEpatents

    Grindley, T.

    1988-04-05

    A process and apparatus for providing additional desulfurization of the hot gas produced in a fluid-bed coal gasifier, within the gasifier is described. A fluid-bed of iron oxide is located inside the gasifier above the gasification bed in a fluid-bed coal gasifier in which in-bed desulfurization by lime/limestone takes place. The product gases leave the gasification bed typically at 1600 to 1800 F and are partially quenched with water to 1000 to 1200 F before entering the iron oxide bed. The iron oxide bed provides additional desulfurization beyond that provided by the lime /limestone. 1 fig.

  2. Archimedean-type force in a cosmic dark fluid. II. Qualitative and numerical study of a multistage universe expansion

    SciTech Connect

    Balakin, Alexander B.; Bochkarev, Vladimir V.

    2011-01-15

    In this (second) part of the work we present the results of numerical and qualitative analysis, based on a new model of the Archimedean-type interaction between dark matter and dark energy. The Archimedean-type force is linear in the four-gradient of the dark energy pressure and plays a role of self-regulator of the energy redistribution in a cosmic dark fluid. Because of the Archimedean-type interaction the cosmological evolution is shown to have a multistage character. Depending on the choice of the values of the model-guiding parameters, the Universe expansion is shown to be perpetually accelerated, periodic or quasiperiodic with a finite number of deceleration/acceleration epochs. We distinguished the models, which can be definitely characterized by the inflation in the early Universe, by the late-time accelerated expansion and nonsingular behavior in intermediate epochs, and classified them with respect to a number of transition points. Transition points appear, when the acceleration parameter changes the sign, providing the natural partition of the Universe's history into epochs of accelerated and decelerated expansion. The strategy and results of numerical calculations are advocated by the qualitative analysis of the instantaneous phase portraits of the dynamic system associated with the key equation for the dark energy pressure evolution.

  3. Use of a polishing scrubber with a fluid bed boiler

    SciTech Connect

    Toher, J.G.

    1996-12-31

    Once viewed as {open_quotes}competitive{close_quotes} technologies, the circulating dry scrubber (CDS){reg_sign} and circulating fluid bed (CFB) boiler are being used together to achieve enhanced performance with lower overall costs. The need to understand the synergy between these two technologies is driven by deregulation of the power industry and the 1990 Clean Air Act Amendments. Deregulation of power production in the US has spurred the growth of Independent Power Producers (IPP) who are responding to Industry`s demand for lower cost fuels, and close attention to annual operating costs. Utilities have to provide {open_quotes}open{close_quotes} access to their transmission lines allowing various IPP`s to connect with the end user. Industrial users can now choose from one of several sources of electricity with prices per kilowatt hour that are much lower than what they are currently being charged. The race is on to reduce power production costs and fuel can be the key in many cases. IPP`s and industry are banding together in very logical ways that can benefit both. Industry`s byproducts with heating value can be sold {open_quotes}over the fence{close_quotes} to an IPP who provides the industry with low cost steam and or electricity in return. However, many alternative lower cost fuels also have a higher emissions potential for criteria pollutants such a SO{sub 2}, NO{sub X}, particulate, or other emissions such as VOC`s and mercury which are more recently receiving attention. Cost effective management of these environmental issues must be an integral part of the project planning process. Three such cases are examined that involve the use of CFB`s with the CDS{reg_sign} as a polishing scrubber for SO{sub 2}. The first two cases involve repowering of existing facilities with petroleum coke as the fuel. The last case involves a new facility powered with low sulfur coal.

  4. Steam activation of a bituminous coal in a multistage fluidized bed pilot plant: Operation and simulation model

    SciTech Connect

    Martin-Gullon, I.; Asensio, M.; Marcilla, A.; Font, R.

    1996-11-01

    A hydrodynamic and kinetic model was developed and applied to simulate the experimental data from a three-stage fluidized bed pilot plant with downcomers. This was used to study the activated carbon production from a Spanish bituminous coal by steam gasification. The steam gasification kinetics, considering the influence of inhibitors, were also determined in a thermobalance. With the kinetic equation and the experimental solids residence time distribution of the pilot plant, the model simulates the overall process that takes place in the reactor. The proposed model is able to reproduce the experimental results satisfactorily.

  5. Fluid-bed fluoride volatility process recovers uranium from spent uranium alloy fuels

    NASA Technical Reports Server (NTRS)

    Barghusen, J. J.; Chilenskas, A. A.; Gunderson, G. E.; Holmes, J. T.; Jonke, A. A.; Kincinas, J. E.; Levitz, N. M.; Potts, G. L.; Ramaswami, D.; Stethers, H.; Turner, K. S.

    1967-01-01

    Fluid-bed fluoride volatility process recovers uranium from uranium fuels containing either zirconium or aluminum. The uranium is recovered as uranium hexafluoride. The process requires few operations in simple, compact equipment, and eliminates aqueous radioactive wastes.

  6. Effluent characterization from a conical pressurized fluid bed

    NASA Technical Reports Server (NTRS)

    Priem, R. J.; Rollbuhler, R. J.; Patch, R. W.

    1977-01-01

    To obtain useable corrosion and erosion results it was necessary to have data with several levels of particulate matter in the hot gases. One level of particulate loading was as low as possible so that ideally no erosion and only corrosion occurred. A conical fluidized bed was used to obtain some degree of filtration through the top of the bed which would not be highly fluidized. This would minimize the filtration required for the hot gases or conversely the amount of particulate matter in the hot gases after a given level of filtration by cyclones and/or filters. The data obtained during testing characterized the effluent from the bed at different test conditions. A range of bed heights, coal flows, air flows, limestone flows, and pressure are represented. These tests were made to determine the best operating conditions prior to using the bed to determine erosion and corrosion rates of typical turbine blade materials.

  7. CHEMICALLY ACTIVE FLUID BED PROCESS FOR SULPHUR REMOVAL DURING GASIFICATION OF CARBONACEOUS FUELS

    EPA Science Inventory

    The report covers the final 3 years of a 9-year program to evaluate the Chemically Active Fluid Bed (CAFB) process for gasification and desulfurization of liquid and solid fuels in a fluidized bed of hot lime. A range of alternative fuels, including three coals and a lignite, wer...

  8. Armoring, stability, and transport driven by fluid flow over a granular bed

    NASA Astrophysics Data System (ADS)

    Allen, Benjamin; Kudrolli, Arshad

    2015-03-01

    We discuss experiments investigating the evolution of a granular bed by a fluid flow as a function of shear rate at the fluid-bed interface. This is a model system to investigate a variety of physical examples including wind blowing over sand, sediment transport in rivers, tidal flows interacting with beaches, flows in slurry pipelines, and sand proppants in hydraulic fracturing. In order to examine the onset and entrainment of the granular bed under steady state conditions, we have constructed a novel conical rheometer system which allows a variable amount of shear to be applied to the granular bed. The grain-fluid system is index matched so that we can visualize the grains away from the sides as well as visualize the fluid flow above and below the interface by using fluorescent tracer particles. We demonstrate that the onset of erosion arises as particles rotate out of their stable position highlighting the importance of torque balance to onset. We find significant armoring of the bed, as the bed is sheared by the fluid flow. Above onset, at least three distinct regions of bed mobility can be found. We will discuss the measured integrated granular flux as a function of shear rate and compare them with empirical laws found in the geophysical literature. Supported by NSF Grant Number CBET 1335928.

  9. Use fluid bed reactor for maleic anhydride from butane

    SciTech Connect

    Arnold, S.C.; Neri, A.; Suciu, G.D.; Verde, L.

    1985-09-01

    A new process is described that incorporates three major improvements over the conventional air oxidation of benzene in a fixed-bed reactor system. The new ALMA Process was developed jointly by Alusuisse Italia and Lummus Crest. It includes the following process improvements: n-Butane feedstock, fluidized-bed reactor system, and a continuous maleic anhydride recovery system using an organic solvent. A summary of the process is given, as well as the steps in its development and its economic advantages.

  10. Fluid and electrolyte shifts during bed rest with isometric and isotonic exercise

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Bernauer, E. M.; Young, H. L.; Morse, J. T.; Juhos, L. T.; Van Beaumont, W.; Staley, R. W.

    1977-01-01

    It is difficult to separate the effects of reduction in hydrostatic pressure from that of reduced energy expenditure when investigating the confinement deconditioning problem. Experiments were conducted on seven healthy young men aged 19-21 yr with the purpose of separating these two factors by using isotonic physical exercise during bed rest to provide a daily energy expenditure greater than normal ambulatory levels. Fluid and electrolyte shifts were measured during three two-week bed rest periods, each of which being separated by a three-week ambulatory recovery period. During two of the three bed rest periods they performed isometric and isotonic exercises to compare their effects on fluid and electrolyte shifts during bed rest. It is shown that during bed rest, preservation of the extracellular volume takes precedence over maintenance of the plasma volume and that this mechanism is independent of the effects of isometric or isotonic exercise.

  11. Fluid bed porosity mathematical model for an inverse fluidized bed bioreactor with particles growing biofilm.

    PubMed

    Campos-Díaz, K E; Bandala-González, E R; Limas-Ballesteros, R

    2012-08-15

    A new mathematic model to estimate bed porosity as a function of Reynolds and Archimedes numbers was developed based in experimental data. Experiments were performed using an inverse fluidized bed bioreactor filled with polypropylene particles, Lactobacillus acidophillus as the immobilized strain and fluidized with a Man-Rogosa-Sharpe culture medium under controlled temperature and pH conditions. Bed porosity was measured at different flow rates, starting from 0.95 to 9.5 LPM. The new model has several advantages when compared with previously reported. Among them, advantages such as standard deviation values ≤ 1% between experimental and calculated bed porosity, its applicability in traditional and inverse fluidization, wall effects do not take account, it gives excellent agreement with spherical particles with or without biofilm, and inertial drag coefficient allow extend the new model a non-spherical particles. PMID:22484706

  12. Changes in body fluid compartments during a 28-day bed rest

    NASA Technical Reports Server (NTRS)

    Fortney, Suzanne M.; Hyatt, Kenneth H.; Davis, John E.; Vogel, John M.

    1991-01-01

    Serial isotope measurements were used to obtain measurements of the body fluid responses of 10 22-29-year-old men during 28 d of simulated microgravity (bed rest). The subjects were maintained on a controlled metabolic diet for 7 d before the study, during 14 d of ambulatory control, 28 d of horizontal bed rest, and 14 d of ambulant recovery. Fluid compartments were measured on control days 1 and 9, bed rest days 2, 14, and 28, and recovery days 7 and 14. By day 2 of bed rest, plasma volume and extracellular volume (ECV) decreased significantly by an average 209 and 533 ml, respectively. Red cell volume and total body water (TBW) decreased more slowly, with average losses of 128 and 1316 ml, respectively, after 28 d of bed rest. Early in the bed rest, TBW loss was mostly from the ECV. Thereafter, the TBW deficit was derived from the intracellular compartment, which decreased an average of 838 ml after 28 d. These results suggest losses from all fluid compartments during bed rest, with no evidence of restoration of ECV after 1-2 weeks.

  13. Effects of exercise on fluid exchange and body composition in man during 14-day bed rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Bernauer, E. M.; Juhos, L. T.; Young, H. L.; Morse, J. T.; Staley, R. W.

    1977-01-01

    A description is presented of an investigation in which body composition, fluid intake, and fluid and electrolyte losses were measured in seven normal, healthy men during three 2-wk bed-rest periods, separated by two 3-wk recovery periods. During bed rest the subjects remained in the horizontal position continuously. During the dietary control periods, body mass decreased significantly with all three regimens, including no exercise, isometric exercise, and isotonic excercise. During bed rest, body mass was essentially unchanged with no exercise, but decreased significantly with isotonic and isometric exercise. With one exception, there were no statistically significant changes in body density, lean body mass, or body fat content by the end of each of the three bed-rest periods.

  14. Physiology of Fluid and Electrolyte Responses During Inactivity: Water Immersion and Bed Rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    1984-01-01

    This manuscript emphasizes the physiology of fluid-electrolyte-hormonal responses during the prolonged inactivity of bed rest and water immersion. An understanding of the total mechanism of adaptation (deconditioning) should provide more insight into the conditioning process. Findings that need to be confirmed during bed rest and immersion are: (1) the volume and tissues of origin of fluid shifted to the thorax and head; (2) interstitial fluid pressure changes in muscle and subcutaneous tissue, particularly during immersion; and (3) the composition of the incoming presumably interstitial fluid that contributes to the early hypervolemia. Better resolution of the time course and source of the diuretic fluid is needed. Important data will be forthcoming when hypotheses are tested involving the probable action of the emerging diuretic and natriuretic hormones, between themselves and among vasopressin and aldosterone, on diuresis and blood pressure control.

  15. Synchronous droplets as a test bed for pulsatory active fluids

    NASA Astrophysics Data System (ADS)

    Katsikis, Georgios; Prakash, Manu

    2014-11-01

    Collective behavior in many-body systems has been studied extensively focusing on a wide range of interacting entities including: flocking animals, sedimenting particles and microfluidic droplets among others. Here, we propose an experimental platform to explore an oscillatory active fluid with synchronous ferrofluid droplets immersed in an immiscible carrier fluid in a Hele-Shaw configuration. The droplets are organized and actuated on a 2-D uniform grid through application of a precessive magnetic field. The state of our system is dependent on three parameters: the grid occupancy with fluid droplets, the grid geometry and the magnetic field. We study the long range orientational order of our system over a range of those parameters by tracking the motion of the droplets and analyzing the PIV data of the carrier fluid flow. Numerical simulations are juxtaposed with experimental data for prediction of the system's behavior.

  16. Physiological responses to prolonged bed rest and fluid immersion in humans

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.

    1984-01-01

    For many centuries, physicians have used prolonged rest in bed and immersion in water in the treatment of ailments and disease. Both treatments have positive remedial effects. However, adverse physiological responses become evident when patients return to their normal daily activities. The present investigation is concerned with an analysis of the physiological changes during bed rest and the effects produced by water immersion. It is found that abrupt changes in body position related to bed rest cause acute changes in fluid compartment volumes. Attention is given to fluid shifts and body composition, renal function and diuresis, calcium and phosphorus metabolism, and orthostatic tolerance. In a discussion of water immersion, fluid shifts are considered along with cardiovascular-respiratory responses, renal function, and natriuretic and diuretic factors.

  17. Multi-stage flash degaser

    DOEpatents

    Rapier, P.M.

    1980-06-26

    A multi-stage flash degaser is incorporated in an energy conversion system having a direct-contact, binary-fluid heat exchanger to remove essentially all of the noncondensable gases from geothermal brine ahead of the direct-contact binary-fluid heat exchanger in order that the heat exchanger and a turbine and condenser of the system can operate at optimal efficiency.

  18. METAL FILTERS FOR PRESSURIZED FLUID BED COMBUSTION (PFBC) APPLICATIONS

    SciTech Connect

    M.A. Alvin

    2004-01-02

    Advanced coal and biomass-based gas turbine power generation technologies (IGCC, PFBC, PCFBC, and Hipps) are currently under development and demonstration. Efforts at the Siemens Westinghouse Power Corporation (SWPC) have been focused on the development and demonstration of hot gas filter systems as an enabling technology for power generation. As part of the demonstration effort, SWPC has been actively involved in the development of advanced filter materials and component configuration, has participated in numerous surveillance programs characterizing the material properties and microstructure of field-tested filter elements, and has undertaken extended, accelerated filter life testing programs. This report reviews SWPC's material and component assessment efforts, identifying the performance, stability, and life of porous commercial metal, advanced alloy, and intermetallic filters under simulated, pressurized fluidized-bed combustion (PFBC) conditions.

  19. Velocity profiles and rheology of a granular bed sheared by a fluid flow

    NASA Astrophysics Data System (ADS)

    Allen, Benjamin; Kudrolli, Arshad

    We discuss an experimental investigation of motion of a granular bed driven by a laminar fluid flow as a function of applied shear rate. This is a model system to investigate a variety of examples where such a situation arises including wind blowing over sand, sediment transport in rivers, slurries, and turbidity currents. We have developed an experimental apparatus which allows examination of the fluid as well as the grain dynamics both at the surface as well as deep into the bed under steady state conditions with refractive index matching technique. This allows us to obtain both the applied local shear stress by the fluid as well as the local strain rate inside the bed. We find that that the granular flux as a function of depth decays exponentially into the bed. Further, the velocity profile is observed to exhibit a crossover from a regime where particles are fully suspended to where there is bed load transport. We will discuss the observed velocity and density profiles in light of various models of granular suspensions. Supported by NSF CBET - 1335928.

  20. The pilot scale testing of a circulating fluid bed fine particulate and mercury control device

    SciTech Connect

    Helfritch, D.J.; Feldman, P.L.

    1998-07-01

    US utilities are faced with new economic challenges to remain competitive in light of deregulation initiatives and increased competition. In addition, environmental pressures are forcing many of these utilities to be prepared to reduce the air emissions such as NO{sub x}, SO{sub x}, fine particulates and mercury from coal-burning plants. The proposed PM{sub 2.5} regulations will demand improved fine particle control from existing equipment, and potential mercury vapor regulations would impose the installation of new control equipment. The device described here employs a circulating fluid bed in order to achieve a high particle density, which promotes the agglomeration of particles. The fine particles entering the system are formed into larger agglomerates, which are then more readily captured by a conventional electrostatic precipitator. Activated carbon cab be injected into the circulating bed for the adsorption of mercury vapor. High residence time, due to the recirculation, allows very effective utilization of the carbon. The fluid bed device was operated for a three-month period on a slipstream of gas exiting a coal-fired boiler at PSE and G's Mercer Generating Station. The results showed that fine particles and mercury vapor can be significantly reduced by passage through a fluidized bed of fly ash and activated carbon. The addition of lime to the fluid bed resulted in effective capture of SO{sub 2} and HCI. These results and the effects of various parameters on capture efficiencies are presented.

  1. Onset and cessation of grain motion in fluid-sheared beds

    NASA Astrophysics Data System (ADS)

    Clark, Abe; Salevan, Julia; Shattuck, Mark; Ouellette, Nick; O'Hern, Corey

    2015-11-01

    We performed molecular dynamics simulations of granular beds driven by a model hydrodynamic shear flow to elucidate general grain-scale mechanisms that determine the onset and cessation of sediment transport. By varying the Shields number (the nondimensional shear stress at the top of the bed) and particle Reynolds number (the ratio of particle inertia to viscous damping), we explore how variations of the fluid flow rate, particle inertia, and fluid viscosity affect the onset and cessation of bed motion. For low to moderate particle Reynolds numbers, a critical boundary separates mobile and static states. Transition times between these states diverge as this boundary is approached both from above and below. At high particle Reynolds number, inertial effects become dominant, and particle motion can be sustained well below flow rates at which mobilization of a static bed occurs. We also find that the onset of bed motion (for both low and high particle Reynolds numbers) is described by Weibullian weakest-link statistics, and thus is crucially dependent on the packing structure of the granular bed, even deep beneath the surface. This work was supported by the US Army Research Office under Grant No. W911NF-14-1-0005.

  2. Analysis and control of the METC fluid bed gasifier. Quarterly report, April 1995--June 1995

    SciTech Connect

    1995-06-01

    This document summarizes work performed for the period 4/1/95 to 7/31/95 on contract no. DE-FG21-94MC31384 (Work accomplished during the period 10/1/94 to 3/31/94 was summarized in the previous technical progress report included in the appendix of this report). In this work, three components will form the basis for design of a control scheme for the Fluidized Bed Gasifier (FBG) at METC: (1) a control systems analysis based on simple linear models derived from process data, (2) review of the literature on fluid bed gasifier operation and control, and (3) understanding of present FBG operation and real world considerations. Tasks accomplished during the present reporting period include: (1) Completion of a literature survey on Fluid Bed Gasifier control, (2) Observation of the FBG during the week of July 17 to July 21, and (3) Suggested improvements to the control of FBG backpressure and MGCR pressure.

  3. The development of a microwave fluid-bed processor. I. Construction and qualification of a prototype laboratory unit.

    PubMed

    Doelling, M K; Jones, D M; Smith, R A; Nash, R A

    1992-11-01

    The static bed- and planetary-type microwave dryers currently available to process pharmaceutical materials are not designed to use hot-air fluidization for the purpose of maximizing microwave energy inputs and particle drying. To take advantage of the benefits offered by fluidization, a 1-kg Uni-Gatt laboratory fluid bed processor was modified to support microwave-assisted fluid bed drying of several representative pharmaceutical granulations. The construction, design features, and validation of this new microwave fluid bed processor are presented. PMID:1475238

  4. The Hydrodynamic Stability of a Fluid-Particle Flow: Instabilities in Gas-Fluidized Beds

    ERIC Educational Resources Information Center

    Liu, Xue; Howley, Maureen A.; Johri, Jayati; Glasser, Benjamin J.

    2008-01-01

    A simplified model of an industrially relevant fluid-particle flow system is analyzed using linear stability theory. Instabilities of the uniform state of a fluidized bed are investigated in response to small flow perturbations. Students are expected to perform each step of the computational analysis, and physical insight into key mechanistic…

  5. Turbulent flow over a channel with fluid-saturated porous bed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The characteristics of fully developed turbulent flow in a hybrid domain channel, which consists of a clear fluid region and a porous bed, are examined numerically using a model based on the macroscopic Reynolds-averaged Navier–Stokes equations. By adopting the classical continuity interface conditi...

  6. IMPROVING DESIGN AND OPERATION OF MULTIPLE-HEARTH AND FLUID BED SLUDGE INCINERATORS

    EPA Science Inventory

    The purpose of the investigation is to document improvements in design, operation, and maintenance of multiple-hearth and fluid bed furnace incineration for combustion of sludge in municipal wastewater treatment plants. The information contained in the report is intended to suppl...

  7. Centaur Test Bed (CTB) for Cryogenic Fluid Management

    NASA Technical Reports Server (NTRS)

    Sakla, Steven; Kutter, Bernard; Wall, John

    2006-01-01

    Future missions such as NASA s space exploration vision and DOD satellite servicing will require significant increases in the understanding and knowledge of space based cryogenic fluid management (CFM), including the transfer and storage of cryogenic fluids. Existing CFM capabilities are based on flight of upper stage cryogenic vehicles, scientific dewars, a few dedicated flight demonstrations and ground testing. This current capability is inadequate to support development of the CEV cryogenic propulsion system, other aspects of robust space exploration or the refueling of satellite cryo propulsion systems with reasonable risk. In addition, these technologies can provide significant performance increases for missions beyond low-earth orbit to enable manned missions to the Moon and beyond. The Centaur upper-stage vehicle can provide a low cost test platform for performing numerous flight demonstrations of the full breadth of required CFM technologies to support CEV development. These flight demonstrations can be performed as secondary mission objectives using excess LH2 and/or LO2 from the main vehicle propellant tanks following primary spacecraft separation at minimal cost and risk.

  8. Assessment of the energy dissipation parameters inside the draft tube of a liquid spout-fluid bed.

    PubMed

    Erbíl, Ayşe Ceçen; Turan, Mustafa

    2005-04-15

    Spouted beds are fluid-particle contactors in which the fluid is introduced centrally through a nozzle instead of a distributor plate, resulting in a regular particle circulation pattern. To assess the suitability of such sytems to environmental engineering applications such as filter backwashing and biofilm systems, a priori knowledge of the energy dissipation parameters is essential. A new model is developed for evaluating the energy dissipation parameters inside the draft tube of spout-fluid beds. The shear stress, velocity gradient, and turbulence fluctuation parameters in the draft tube of a liquid spout-fluid bed are calculated with the help of an energy equation for flows carrying suspensions and the experimentally determined pressure losses inside the draft tube and compared with results for particulately fluidized beds. A spout-fluid bed with a draft tube provides higher shear stress inside the draft tube than a fluidized bed. The mean velocity gradient in the draft tube is comparable to and higher than in a fluidized bed and increases with solids fraction. The turbulence dissipation coefficient decreases very slightlywith increasing solids fraction for both systems. Consequently, according to the model calculations, a spout-fluid bed with a draft tube can be an alternative to the classical fluidized bed filter backwashing system. PMID:15884391

  9. Fluid and salt supplementation effect on body hydration and electrolyte homeostasis during bed rest and ambulation

    NASA Astrophysics Data System (ADS)

    Zorbas, Yan G.; Kakurin, Vassily J.; Kuznetsov, Nikolai A.; Yarullin, Vladimir L.

    2002-06-01

    Bed rest (BR) induces significant urinary and blood electrolyte changes, but little is known about the effect of fluid and salt supplements (FSS) on catabolism, hydration and electrolytes. The aim was to measure the effect of FSS on catabolism, body hydration and electrolytes during BR. Studies were done during 7 days of a pre-bed rest period and during 30 days of a rigorous bed rest period. Thirty male athletes aged, 24.6±7.6 years were chosen as subjects. They were divided into three groups: unsupplemented ambulatory control subjects (UACS), unsupplemented bed rested subjects (UBRS) and supplemented bed rested subjects (SBRS). The UBRS and SBRS groups were kept under a rigorous bed rest regime for 30 days. The SBRS daily took 30 ml water per kg body weight and 0.1 sodium chloride per kg body weight. Plasma sodium (Na), potassium (K), calcium (Ca) and magnesium (Mg) levels, urinary Na, K, Ca and Mg excretion, plasma osmolality, plasma protein level, whole blood hemoglobin (Hb) and hematocrit (Hct) level increased significantly ( p≤0.05), while plasma volume (PV), body weight, body fat, peak oxygen uptake, food and fluid intake decreased significantly ( p≤0.05) in the UBRS group when compared with the SBRS and UACS groups. In contrast, plasma and urinary electrolytes, osmolality, protein level, whole blood Hct and Hb level decreased significantly ( p≤0.05), while PV, fluid intake, body weight and peak oxygen uptake increased significantly ( p≤0.05) in the SBRS group when compared with the UBRS group. The measured parameters did not change significantly in the UACS group when compared with their baseline control values. The data indicate that FSS stabilizes electrolytes and body hydration during BR, while BR alone induces significant changes in electrolytes and body hydration. We conclude that FSS may be used to prevent catabolism and normalize body hydration status and electrolyte values during BR.

  10. Analysis and control of the METC fluid bed gasifier. Quarterly report, July 1--September 30, 1995

    SciTech Connect

    1995-12-31

    In this work, three components will form the basis for design of a control scheme for the Fluidized Bed Gasifier (FBG) at METC: (1) a control systems analysis based on simple linear models derived from process data; (2) review of the literature on fluid bed gasifier operation and control; and (3) understanding of present FBG operation and real world considerations. Tasks accomplished during the present reporting period include: (1) observation of the FBG during the week of July 17 to July 21; (2) suggested improvements to the control of FBG backpressure and MGCR pressure; and (3) data collection from FBG run No. 11 and transfer of data to USC.

  11. Analysis and control of the METC fluid bed gasifier. Quarterly progress report, January--March 1995

    SciTech Connect

    1995-03-01

    This document summarizes work performed for the period 10/1/94 to 3/31/95. In this work, three components will form the basis for design of a control scheme for the Fluidized Bed Gasifier (FBG) at METC: (1) a control systems analysis based on simple linear models derived from process data, (2) review of the literature on fluid bed gasifier operation and control, and (3) understanding of present FBG operation and real world considerations. Below we summarize work accomplished to data in each of these areas.

  12. Chemical and textural characteristics of multistage fluid inclusions with high Li/B ratio found from the Sanbagawa belt.

    NASA Astrophysics Data System (ADS)

    Yoshida, K.; Hirajima, T.

    2012-04-01

    Recent studies invoked that the variation of peculiar fluid soluble light elements, such as Li, B and Cl, are capable of suggesting generation depths of fluid released in subduction zones (e.g., Scambelluri et al., 2004; Bebout et al., 2007; Marschall et al., 2009). Crush-leached fluids extracted from quartz veins intercalated with metabasites of the Sanbagawa metamorphic belt show high Li and B concentrations, whose Li/B ratios show a positive correlation with metamorphic grade of the host rocks, i.e., from 0.02 for pumpellyite-actinolite facies to 0.27 for eclogite facies (Sengen et al., 2009). Furthermore, crush-leached fluids extracted from quartz veins intercalated with metasediments in proximal to the eclogite unit in the Besshi district show much higher Li/B ratio (ca. 0.36-1.99). Yoshida et al. (2011) pointed out that Li/B ratio of dehydrated fluids was controlled by the rock types of the host rocks, i.e., Li/B ratio of dehydrated fluids derived from tourmaline-free metasediments show much higher values than those expected from metabasites. Those obtained data suggest that the Li/B ratio of the deep fluid has a potential as a depth indicator but there remain many unknown factors for establishing it. The Li/B ratio of extracted fluid obtained by the crush-leached method integrates the whole fluid activities which the host rocks were taken place. To investigate the fluid activity history for the sample showing the highest Li/B ratio (1.99), detailed petrographical and microthemometric studies were performed. The studied sample IR04 is a foliation-parallel quartz vein intercalated with a Grt-Hbl-Ph schist probably derived from clay, whose peak P-T conditions are estimated as 600 °C and 1.3 GPa using pseudosection analysis. The quartz vein shows a foam microstructure, suggesting that low differential stress and high-T conditions were attained during its texture formation. Three types of fluid inclusions have been identified: the earliest one, FIA-I, is

  13. Multi-stage Ag-Bi-Co-Ni-U and Cu-Bi vein mineralization at Wittichen, Schwarzwald, SW Germany: geological setting, ore mineralogy, and fluid evolution

    NASA Astrophysics Data System (ADS)

    Staude, Sebastian; Werner, Wolfgang; Mordhorst, Teresa; Wemmer, Klaus; Jacob, Dorrit E.; Markl, Gregor

    2012-03-01

    The Wittichen Co-Ag-Bi-U mining area (Schwarzwald ore district, SW Germany) hosts several unconformity-related vein-type mineralizations within Variscan leucogranite and Permian to Triassic redbeds. The multistage mineralization formed at the intersection of two fault systems in the last 250 Ma. A Permo-Triassic ore stage I with minor U-Bi-quartz-fluorite mineralization is followed by a Jurassic to Cretaceous ore stage II with the main Ag and Co mineralization consisting of several generations of gangue minerals that host the sub-stages of U-Bi, Bi-Ag, Ni-As-Bi and Co-As-Bi. Important ore minerals are native elements, Co and Ni arsenides, and pitchblende; sulphides are absent. The Miocene ore stage III comprises barite with the Cu-Bi sulfosalts emplectite, wittichenite and aikinite, and the sulphides anilite and djurleite besides native Bi, chalcopyrite, sphalerite, galena and tennantite. The mineral-forming fluid system changed from low salinity (<5 wt.% NaCl) at high temperature (around 300°C) in Permian to highly saline (around 25 wt.% NaCl + CaCl2) at lower temperatures (50-150°C) in Triassic to Cretaceous times. Thermodynamic calculations and comparison with similar mineralizations worldwide show that the Mesozoic ore-forming fluid was alkaline with redox conditions above the hematite-magnetite buffer. We suggest that the precipitation mechanism for native elements, pitchblende and arsenides is a decrease in pH during fluid mixing processes. REE patterns in fluorite and the occurrence of Bi in all stages suggest a granitic source of some ore-forming elements, whereas, e.g. Ag, Co and Ni probably have been leached from the redbeds. The greater importance of Cu and isotope data indicates that the Miocene ore stage III is more influenced by fluids from the overlying redbeds and limestones than the earlier mineralization stages.

  14. Composition of fluid inclusions in Permian salt beds, Palo Duro Basin, Texas, U.S.A.

    USGS Publications Warehouse

    Roedder, E.; d'Angelo, W. M.; Dorrzapf, A.F., Jr.; Aruscavage, P. J.

    1987-01-01

    Several methods have been developed and used to extract and chemically analyze the two major types of fluid inclusions in bedded salt from the Palo Duro Basin, Texas. Data on the ratio K: Ca: Mg were obtained on a few of the clouds of tiny inclusions in "chevron" salt, representing the brines from which the salt originally crystallized. Much more complete quantitative data (Na, K, Ca, Mg, Sr, Cl, SO4 and Br) were obtained on ??? 120 individual "large" (mostly ???500 ??m on an edge, i.e., ??? ??? 1.6 ?? 10-4 g) inclusions in recrystallized salt. These latter fluids have a wide range of compositions, even in a given piece of core, indicating that fluids of grossly different composition were present in these salt beds during the several (?) stages of recrystallization. The analytical results indicating very large inter-and intra-sample chemical variation verify the conclusion reached earlier, from petrography and microthermometry, that the inclusion fluids in salt and their solutes are generally polygenetic. The diversity in composition stems from the combination of a variety of sources for the fluids (Permian sea, meteoric, and groundwater, as well as later migrating ground-, formation, or meteoric waters of unknown age), and a variety of subsequent geochemical processes of dissolution, precipitation and rock-water interaction. The compositional data are frequently ambiguous but do provide constraints and may eventually yield a coherent history of the events that produced these beds. Such an understanding of the past history of the evaporite sequence of the Palo Duro Basin should help in predicting the future role of the fluids in the salt if a nuclear waste repository is sited there. ?? 1987.

  15. The design of circulating fluid bed boilers for utility power generation

    SciTech Connect

    Maitland, J.; Skowyra, R.

    1997-12-31

    Fluid bed combustion technology has been utilized in a broad range of industries to produce steam and electricity. The advantages of circulating fluid bed technology, including the ability to use both conventional and waste fuels in an environmentally sound combustion process, have been the driving forces for the selection of CFB by numerous companies. An important trend in the market development for CFB has been increased interest in the scale-up of units to larger, utility size applications. The environmental and fuel flexibility features are also of strong interest for companies looking for 150--400 MW output. The worldwide private power industry has utilized fluidized bed combustion as one of its options for power development. ABB Combustion Engineering has been a leader in the design of these larger units. This paper will provide specific details on the design and operation of large scale fluidized bed for power generation, along with a review of the impact of different fuels on unit design. The authors will include their perspective on the future for advanced CFB designs also.

  16. Effect of cohesion on granular-fluid flows in spouted beds: PIV measurement and DEM simulations

    NASA Astrophysics Data System (ADS)

    Zhu, Runru; LI, Shuiqing; Yao, Qiang

    2013-06-01

    In contrast to wet granular flows, the effect of cohesion on complex granular-fluid flows is intriguing but much challenging. The liquid bridges, forming between binary particles with the addition of a small amount of liquids, might significantly change the granular-fluid system due to both cohesion and lubrication effects. In this paper, a spouted bed, among various fluidization technologies, is particularly selected as a prototypical system for studying granular-fluid flows, since it can provide a quasi-steady flow pattern of granular particles, i.e., a core of upward granular-fluid flow called the "spout" and a surrounding region of downward quasi-static granular flow called the "annulus". Firstly, using self-developed particle image velocimetery (PIV) technique, the effects of cohesion on the spout-annulus interface (namely the spout width) and on the particle velocity profiles in distinct zones are examined. Further, the discrete element method (DEM), by incorporating liquid bridge adhesion into soft-sphere model, is established and used to predict the microdynamic behavior of particles in spouted beds. Finally, based on both experiments and DEM validation, the effects on the granular patterns in these two zones are comparatively discussed.

  17. Multi-stage barites in partially melted UHP eclogite: implications for fluid/melt activities during deep continental subduction in the Sulu orogenic belt

    NASA Astrophysics Data System (ADS)

    Wang, Songjie; Wang, Lu

    2015-04-01

    . Zr-in-rutile thermometry shows their formation temperature to be 586-664 oC at 1.5-2.5 GPa. Barite-bearing MS inclusions with Ba-bearing K-feldspar (type-II) connected by Kfs+Pl+Bt veinlets of in-situ phengite breakdown and thin barite veinlets along grain boundaries (type-III) are products of phengite breakdown and induced fluid flow during exhumation. These barites have witnessed the gradational separation process of melt/ fluid from miscibility on/above the second critical endpoint during UHP metamorphism, to immiscibility along the exhumation path of the subducted slab. Associated reactions from pyrite to hematite and goethite with the type-III barite ring surrounding the pyrite provide evidence for a local high oxygen fugacity environment during eclogite partial melting and subsequent melt/fluid crystallization processes. Moreover, large grain barite aggregations (type-IV) modified by amphibole+albite symplectite are most likely formed by release of molecular and hydroxyl water from anhydrous minerals of eclogite during high-grade amphibolite-facies retrogression. The growth of multi-stage barites in UHP eclogite further advances our understanding of fluid/melt transfer, crystallization processes along the subduction-exhumation path of the partially melted eclogite, broadening our knowledge of melt/fluid evolution within subduction-collision zones worldwide. REFERENCES Chen Y.X., et al., 2014, Lithos, 200, 1-21. Liu J.B., et al., 2000, Acta Petrologica Sinica 16(4), 482-484. Zeng L.S., et al., 2007, Chinese Science Bulletin, 52(21), 2995-3001. Gao X.Y., et al., 2012, Journal of Metamorphic Geology, 30(2), 193-212.

  18. Fluid-particle interaction and generation of coherent structures over permeable beds: an experimental analysis

    NASA Astrophysics Data System (ADS)

    Corvaro, Sara; Miozzi, Massimo; Postacchini, Matteo; Mancinelli, Alessandro; Brocchini, Maurizio

    2014-10-01

    process, while the former occurs before flow inversion and close to the porous bed. This result reveals that nearbed small-scale phenomena are weakly influenced by the wave mean flow. A detailed description of fluid suction and injection is proposed in terms of the mean flow dynamics (at wave scale), while the actual inflow/outflow of particles at the bed is seen to depend on local, small-scale flow properties. Suction and injection are generated during positive and negative water surface elevations and either squeeze or expand the flow downward/upward. The suction/injection perturbations contribute to the triggering of sweep and ejection events. Suction is mainly concentrated very close to the bed, injection is rapidly transported above the BBL, but the highest turbulence occurs in correspondence of suction events.

  19. Multi-stage flash degaser

    DOEpatents

    Rapier, Pascal M.

    1982-01-01

    A multi-stage flash degaser (18) is incorporated in an energy conversion system (10) having a direct-contact, binary-fluid heat exchanger to remove essentially all of the noncondensable gases from geothermal brine ahead of the direct-contact binary-fluid heat exchanger (22) in order that the heat exchanger (22) and a turbine (48) and condenser (32) of the system (10) can operate at optimal efficiency.

  20. Fluid modelling of a packed bed dielectric barrier discharge plasma reactor

    NASA Astrophysics Data System (ADS)

    Van Laer, Koen; Bogaerts, Annemie

    2016-02-01

    A packed bed dielectric barrier discharge plasma reactor is computationally studied with a fluid model. Two different complementary axisymmetric 2D geometries are used to mimic the intrinsic 3D problem. It is found that a packing enhances the electric field strength and electron temperature at the contact points of the dielectric material due to polarization of the beads by the applied potential. As a result, these contact points prove to be of direct importance to initiate the plasma. At low applied potential, the discharge stays at the contact points, and shows the properties of a Townsend discharge. When a high enough potential is applied, the plasma will be able to travel through the gaps in between the beads from wall to wall, forming a kind of glow discharge. Therefore, the inclusion of a so-called ‘channel of voids’ is indispensable in any type of packed bed modelling.

  1. Effect of dietary sodium on fluid/electrolyte regulation during bed rest

    NASA Technical Reports Server (NTRS)

    Williams, W. Jon; Schneider, Suzanne M.; Gretebeck, Randall J.; Lane, Helen W.; Stuart, Charles A.; Whitson, Peggy A.

    2003-01-01

    BACKGROUND: A negative fluid balance during bed rest (BR) is accompanied by decreased plasma volume (PV) which contributes to cardiovascular deconditioning. HYPOTHESIS: We hypothesized that increasing dietary sodium while controlling fluid intake would increase plasma osmolality (POSM), stimulate fluid conserving hormones, and reduce fluid/electrolyte (F/E) losses during BR; conversely, decreasing dietary sodium would decrease POSM, suppress fluid conserving hormones, and increase F/E losses. METHODS: We controlled fluid intake (30 ml x kg(-1) x d(-1)) in 17 men who consumed either a 4.0 +/- 0.06 g x d(-1) (174 mmol x d(-1)) (CONT; n = 6), 1.0 +/- 0.02 g x d(-1) (43 mmol x d(-1)) (LS; n = 6), or 10.0 +/- 0.04 g x d(-1) (430 mmol x d(-1)) (HS; n = 5) sodium diet before, during, and after 21 d of 6 degrees head-down BR. PV, total body water, urine volume and osmolality, POSM, and F/E controlling hormone concentrations were measured. RESULTS: In HS subjects, plasma renin activity (-92%), plasma/urinary aldosterone (-59%; -64%), and PV (-15.0%; 6.0 ml x kg(-1); p < 0.05) decreased while plasma atrial natriuretic peptide (+34%) and urine antidiuretic hormone (+24%) increased during BR (p < 0.05) compared with CONT. In LS, plasma renin activity (+166%), plasma aldosterone (+167%), plasma antidiuretic hormone (+19%), and urinary aldosterone (+335%) increased with no change in PV compared with CONT (p < 0.05). Total body water did not change in any of the subjects. CONCLUSIONS: Contrary to our hypothesis, increasing dietary sodium while controlling fluid intake during BR resulted in a greater loss of PV compared with the CONT subjects. Reducing dietary sodium while controlling fluid intake did not alter the PV response during BR compared with CONT subjects.

  2. CFD study on local fluid-to-wall heat transfer in packed beds and field synergy analysis

    NASA Astrophysics Data System (ADS)

    Peng, Wenping; Xu, Min; Huai, Xiulan; Liu, Zhigang

    2016-04-01

    To reach the target of smaller pressure drop and better heat transfer performance, packed beds with small tube-to-particle diameter ratio ( D/d p<10) have now been considered in many areas. Fluid-to-wall heat transfer coefficient is an important factor determining the performance of this type of beds. In this work, local fluid- to-wall heat transfer characteristic in packed beds was studied by Computational Fluid Dynamics (CFD) at different Reynolds number for D/d p=1.5, 3.0 and 5.6. The results show that the fluid-to-wall heat transfer coefficient is oscillating along the bed with small tube-to-particle diameter ratio. Moreover, this phenomenon was explained by field synergy principle in detail. Two arrangement structures of particles in packed beds were recommended based on the synergy characteristic between flow and temperature fields. This study provides a new local understanding of fluid-to-wall heat transfer in packed beds with small tube-to-particle diameter ratio.

  3. Study of ebullated bed fluid dynamics. Final progress report, September 1980-July 1983

    SciTech Connect

    Schaefer, R.J.; Rundell, D.N.; Shou, J.K.

    1983-07-01

    The fluid dynamics occurring in HRI's H-coal process development unit coal liquefaction reactor during Run PDU-10 were measured and compared with Amoco Oil cold-flow fluidization results. It was found that catalyst bed expansions and gas holdups are higher in the PDU than those observed in the cold-flow tests for slurries having the same nominal viscosity. Comparison of PDU results with cold-flow results shows that the bulk of the operating reactor gas flow lies in the ideal bubbly regime. It also appears that the gas bubbles in these PDU tests are rising quite slowly. Only two of the operating points in our test program on the PDU were found to lie in the churn turbulent regime. Existence of churn turbulent behavior during these two experiments is consistent with trends observed in earlier cold-flow experiments. Two- and three-phase fluidization experiments were carried out in Amoco's cold-flow fluid dynamics unit. The data base now includes fluidization results for coal char/kerosene slurry concentrations of 4.0, 9.8, and 20.7 vol% in addition to the 15.5 and 17.8 vol% data from our earlier work. Both HDS-2A and Amocat-1A catalysts were used in the tests. Bed expansion is primarily a function of slurry velocity, with gas velocity having only a weak effect. Bed contractions have been observed in some cases at sufficiently high gas velocity. Gas and liquid holdups were found to be uniform across the cross-section of the Amoco cold-flow fluid dynamics pilot plant. A viscometer was adapted for measurement of the viscosity of coal slurries at high temperature and pressure. Based on experiments carried out in the Amoco cold-flow unit, a significant degree of backmixing was found to occur in the H-Coal system. 70 references, 93 figures, 32 tables.

  4. 3D numerical simulation on fluid flow and heat transfer characteristics in multistage heat exchanger with slit fins

    NASA Astrophysics Data System (ADS)

    Tao, W. Q.; Cheng, Y. P.; Lee, T. S.

    2007-11-01

    In this paper, a numerical investigation is performed for three-stage heat exchangers with plain plate fins and slit fins respectively, with a three-dimensional laminar conjugated model. The tubes are arranged in a staggered way, and heat conduction in fins is considered. In order to save the computer resource and speed up the numerical simulation, the numerical modeling is carried out stage by stage. In order to avoid the large pressure drop penalty in enhancing heat transfer, a slit fin is presented with the strip arrangement of “front coarse and rear dense” along the flow direction. The numerical simulation shows that, compared to the plain plate fin heat exchanger, the increase in the heat transfer in the slit fin heat exchanger is higher than that of the pressure drop, which proves the excellent performance of this slit fin. The fluid flow and heat transfer performance along the stages is also provided.

  5. Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD

    SciTech Connect

    Soria, José; Gauthier, Daniel; Flamant, Gilles; Rodriguez, Rosa; Mazza, Germán

    2015-09-15

    Highlights: • A CFD two-scale model is formulated to simulate heavy metal vaporization from waste incineration in fluidized beds. • MSW particle is modelled with the macroscopic particle model. • Influence of bed dynamics on HM vaporization is included. • CFD predicted results agree well with experimental data reported in literature. • This approach may be helpful for fluidized bed reactor modelling purposes. - Abstract: Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073 K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator.

  6. Multistage Electrophoretic Separators

    NASA Technical Reports Server (NTRS)

    Thomas, Nathan; Doyle, John F.; Kurk, Andy; Vellinger, John C.; Todd, Paul

    2006-01-01

    A multistage electrophoresis apparatus has been invented for use in the separation of cells, protein molecules, and other particles and solutes in concentrated aqueous solutions and suspensions. The design exploits free electrophoresis but overcomes the deficiencies of prior free-electrophoretic separators by incorporating a combination of published advances in mathematical modeling of convection, sedimentation, electro-osmotic flow, and the sedimentation and aggregation of droplets. In comparison with other electrophoretic separators, these apparatuses are easier to use and are better suited to separation in relatively large quantities characterized in the art as preparative (in contradistinction to smaller quantities characterized in the art as analytical). In a multistage electrophoretic separator according to the invention, an applied vertical steady electric field draws the electrically charged particles of interest from within a cuvette to within a collection cavity that has been moved into position of the cuvette. There are multiple collection cavities arranged in a circle; each is aligned with the cuvette for a prescribed short time. The multistage, short-migration-path character of the invention solves, possibly for the first time, the fluid-instability problems associated with free electrophoresis. The figure shows a prototype multistage electrophoretic separator that includes four sample stations and five collection stages per sample. At each sample station, an aqueous solution or suspension containing charged species to be separated is loaded into a cuvette, which is machined into a top plate. The apparatus includes a lower plate, into which 20 collection cavities have been milled. Each cavity is filled with an electrophoresis buffer solution. For the collection of an electrophoretic fraction, the lower plate is rotated to move a designated collection cavity into alignment with the opening of the cuvette. An electric field is then applied between a non

  7. Fluid bed drying of guarana (Paullinia cupana HBK) extract: effect of process factors on caffeine content.

    PubMed

    Pagliarussi, Renata S; Bastos, Jairo K; Freitas, Luis A P

    2006-01-01

    The aim of this study was to study the convective drying of the hydroalcoholic extracts obtained from powdered guarana seeds in a spouted bed dryer. The influence of process variables, such as the convective airflow rate, extract feed rate, and air inlet temperature, on the quality of the dry extract was determined using the caffeine and moisture content for the process evaluation. The caffeine content in the alcoholic and dried extracts was determined by capillary gas chromatography. The experiments were performed following a 3(3) factorial design and the data analyzed by response surface. The analysis of dry extract showed that the air and extract feed rates did not significantly affect (25% level) the caffeine content, but that drying temperature is a major factor to consider when the extract is submitted to fluid bed drying. Caffeine losses were significant (1% level) for drying temperatures above 120 degrees C, while moisture content was lower than 3% for temperatures above 120 degrees C. The data showed that there is an optimum temperature for the drying of guarana extracts in spouted beds, and under the conditions used in this study it was 120 degrees C. PMID:16796371

  8. Effects of Daily Centrifugation on Segmental Fluid Distribution in Bed-rested Subjects

    NASA Technical Reports Server (NTRS)

    Diedrich, Andre; Moore, S. T.; Stenger, M.; Arya, T. M.; Newby, N.; Tucker, J. M.; Milstead, L.; Acock, K.; Knapp, C.; Jevans, J.; Paloski, W.

    2007-01-01

    The effect of daily centrifugation on segmental fluid distribution have been studied during 21 days of 6 degree head down bedrest. One group (N=7) underwent no countermeasure while the other (N=8) received a daily, one hour, dose (2.5 gz at the foot, decreasing to 1.0 gz at the heart) of artificial gravity (AG) training on the Johnson Space Center short radius centrifuge. Fluid shifts of thoracic(VTO), abdominal (VAB), thigh (VTH), and calf (VCA) regions were measured by the tetrapolar segmental body impedance technique. Untrained subjects reduced their total volume from 18.9 plus or minus 0.5L to 17.9 plus or minus 0.9L (MN plus or minus SE, P less than 0.05) while trained subjects maintained their total volume. In untrained, control, subjects after bed rest, there was a trend toward reduced volume in all segments, with significant reductions in thigh and calf (fig, P less than 0.05). Trained subjects maintained volume in all segments. Our data indicate that artificial gravity treatment counteracts bed rest-induced hypovolemia.

  9. Influence of in line monitored fluid bed granulation process parameters on the stability of Ethinylestradiol.

    PubMed

    Roßteuscher-Carl, Katrin; Fricke, Sabine; Hacker, Michael C; Schulz-Siegmund, Michaela

    2015-12-30

    Ethinylestradiol (EE) as a highly active and low dosed compound is prone to oxidative degradation. The stability of the drug substance is therefore a critical parameter that has to be considered during drug formulation. Beside the stability of the drug substance, granule particle size and moisture are critical quality attributes (CQA) of the fluid bed granulation process which influence the tableting ability of the resulting granules. Both CQA should therefore be monitored during the production process by process analytic technology (PAT) according to ICH Q8. This work focusses on the effects of drying conditions on the stability of EE in a fluid-bed granulation process. We quantified EE degradation products 6-alpha-hydroxy-EE, 6-beta-hydroxy-EE, 9(11)-dehydro-EE and 6-oxo-EE during long time storage and accelerated conditions. PAT-tools that monitor granule particle size (Spatial filtering technology) and granule moisture (Microwave resonance technology) were applied and compared with off-line methods. We found a relevant influence of residual granule moisture and thermic stress applied during granulation on the storage stability of EE, whereas no degradation was found immediately after processing. Hence we conclude that drying parameters have a relevant influence on long term EE stability. PMID:26541302

  10. Development and optimization of a solid dispersion hot-melt fluid bed coating method.

    PubMed

    Kennedy, J P; Niebergall, P J

    1996-04-01

    A new hot-melt fluid bed coating process has been developed, characterized, and optimized. Polyethylene glycol served as the model coating agent and was charged with substrate into the fluid bed chamber in the solid state. The processing stages included: (A) warm-up, (B) preheating, (C) melting-spreading, and (D) cooling-congealing. A central composite design was utilized to characterize and optimize the process. Substrate porosity and density evaluations were conducted by mercury intrusion. The method proved capable of coating nonpareils from 10 to 35 mesh (0.500 to 2.00 mm) and tablets up to 1 g. The nonpareils were coated as individual particles, while particle sizes significantly smaller than 40 mesh (0.420 mm) tended to agglomerate. The porosity and density values of dissimilar nonpareil batches showed a large degree of variation, affecting the method's reproducibility. Additive coatings were achieved by sequential runs using coating agents of diminishing melting points. The method is a viable alternative to hot-melt spray-coating processes. Organic solvents, spraying equipment, steam jackets, and/or heating tape are eliminated from the process. PMID:9552331

  11. Rapid formulation screening with a Multipart Microscale Fluid bed Powder processor.

    PubMed

    Kivikero, Niina; Murtomaa, Matti; Antikainen, Osmo; Hatara, Juha; Juppo, Anne-Mari; Sandler, Niklas

    2011-08-01

    The aim of this study was to investigate early formulation screening in small scale with a miniaturized fluid bed device. Altogether eight different batches were granulated in a Multipart Microscale Fluid bed Powder processor (MMFP) with constant process conditions using electrostatic atomization. Atomization voltage and granulation liquid flow rate were kept constant. Acid acetylsalicylic was used as model active pharmaceutical ingredient (API), lactose monohydrate, microcrystalline cellulose and polyvinylpyrrolidone were used as excipients. Granule size distributions were measured with spatial filtering technique. Friability test was performed by spinning granules in the mixer with glass beads. Compressibility of the granules was evaluated by tableting and the breaking force of the tablets was measured. Multivariate analysis, namely partial least squares regression and multilinear regression were applied to the data. It was possible to generate granules of different compositions rapidly employing MMFP with electrostatic atomization fast and acquire reliable and logical results with only small amount of material. However, a major challenge was to find suitable analytical methods for such small batches. PMID:20387990

  12. Fluid Flow through a High Cell Density Fluidized-Bed during Centrifugal Bioreactor Culture

    PubMed Central

    Detzel, Christopher J.; Van Wie, Bernard J.; Ivory, Cornelius F.

    2010-01-01

    An increasing demand for products such as tissues, proteins, and antibodies from mammalian cell suspension cultures is driving interest in increasing production through high-cell density bioreactors. The centrifugal bioreactor (CCBR) retains cells by balancing settling forces with surface drag forces due to medium throughput and is capable of maintaining cell densities above 108 cells/mL. This article builds on a previous study where the fluid mechanics of an empty CCBR were investigated showing fluid flow is nonuniform and dominated by Coriolis forces, raising concerns about nutrient and cell distribution. In this article, we demonstrate that the previously reported Coriolis forces are still present in the CCBR, but masked by the presence of cells. Experimental dye injection observations during culture of 15 μm hybridoma cells show a continual uniform darkening of the cell bed, indicating the region of the reactor containing cells is well mixed. Simulation results also indicate the cell bed is well mixed during culture of mammalian cells ranging in size from 10 to 20 μm. However, simulations also allow for a slight concentration gradient to be identified and attributed to Coriolis forces. Experimental results show cell density increases from 0.16 to 0.26 when centrifugal force is doubled by increasing RPM from 650 to 920 at a constant inlet velocity of 6.5 cm/s; an effect also observed in the simulation. Results presented in this article indicate cells maintained in the CCBR behave as a high-density fluidized bed of cells providing a homogeneous environment to ensure optimal growth conditions. PMID:20205172

  13. Fluid-driven multiple fracture growth from a permeable bedding plane intersected by an ascending hydraulic fracture

    NASA Astrophysics Data System (ADS)

    Zhang, Xi; Jeffrey, Robert G.

    2012-12-01

    In bedded sedimentary rocks, the energy for spontaneous growth of multiple vertical fractures from a bedding plane may be provided by an overpressurized sublayer fracture that connects a fluid source to the bedding plane. In this paper, using our coupled deformation and flow model, we study the processes and mechanisms involved in the formation and interaction of closely space fractures from preexisting flaws or starter fractures located along the bedding plane. Fracture growth from multiple flaws can be convergent, parallel or divergent, depending on the factors like contrasts in moduli and far-field stresses, flaw sizes and locations, and initial bed conductivity, fluid viscosity, and injection rate, as well as time. The results presented here have been obtained for conditions where fluid viscous dissipation is dominant, in contrast to other results available in literature based on uniform pressure assumption equivalent to use of an inviscid fluid. It is demonstrated that the earlier a hydraulic fracture starts to extend, the more likely it is to become the primary fracture in a system of closely spaced fractures. The fracture closest to the fluid source typically grows faster as a result of a higher pressure level because viscous dissipation results in a decrease in pressure with distance from the fluid source. But its development does not completely inhibit the growth of other hydraulic fractures. Simultaneous growth of closely spaced fractures is supported by the local stress and energetic analyses, and the fracture distance can be very small. Their length to spacing ratio is accordingly much larger than that predicted previously. Under certain circumstances, a longer and more permeable fracture may grow to a greater extent than a shorter fracture closer to the fluid source, which may grow toward and merge with the longer fracture to create fracture clusters adjacent to a bedding plane.

  14. Comparison between finite volume and lattice-Boltzmann method simulations of gas-fluidised beds: bed expansion and particle-fluid interaction force

    NASA Astrophysics Data System (ADS)

    Third, J. R.; Chen, Y.; Müller, C. R.

    2016-07-01

    Lattice-Boltzmann method (LBM) simulations of a gas-fluidised bed have been performed. In contrast to the current state-of-the-art coupled computational fluid dynamics-discrete element method (CFD-DEM) simulations, the LBM does not require a closure relationship for the particle-fluid interaction force. Instead, the particle-fluid interaction can be calculated directly from the detailed flow profile around the particles. Here a comparison is performed between CFD-DEM and LBM simulations of a small fluidised bed. Simulations are performed for two different values of the superficial gas velocity and it is found that the LBM predicts a larger bed expansion for both flowrates. Furthermore the particle-fluid interaction force obtained for LBM simulations is compared to the force which would be predicted by a CFD-DEM model under the same conditions. On average the force predicted by the CFD-DEM closure relationship is found to be significantly smaller than the force obtained from the LBM.

  15. Scale-up of an electrical capacitance tomography sensor for imaging pharmaceutical fluidized beds and validation by computational fluid dynamics

    NASA Astrophysics Data System (ADS)

    Wang, Haigang; Yang, Wuqiang

    2011-10-01

    The aim of this research is to apply electrical capacitance tomography (ECT) in pharmaceutical fluidized beds and scale up the application of ECT from a lab-scale fluidized bed to a production-scale fluidized bed. The objective is to optimize the design of the production-scale fluidized bed and to improve the operation efficiency of the fluidization processes. This is the first time that ECT has been scaled up to a production-scale fluidized bed of 1.0 m diameter and batch process capacity of 100 kg in a real industrial environment. With a large-scale fluidized bed in a real industrial environment, some key issues on the ECT sensor design must be addressed. To validate ECT measurement results, a two-phase flow model has been used to simulate the process in a lab-scale and pilot-scale fluidized bed. The key process parameters include solid concentration, average concentration profiles, the frequency spectrum of signal fluctuation obtained by the fast Fourier transfer (FFT) and multi-level wavelet decomposition in the time domain. The results show different hydrodynamic behaviour of fluidized beds of different scales. The time-averaged parameters from ECT and computational fluid dynamics are compared. Future work on the ECT sensor design for large-scale fluidized beds are given in the end of the paper.

  16. Body fluid alterations during head-down bed rest in men at moderate altitude

    NASA Technical Reports Server (NTRS)

    Loeppky, J. A.; Roach, R. C.; Selland, M. A.; Scotto, P.; Luft, F. C.; Luft, U. C.

    1993-01-01

    To determine the effects of hypoxia on fluid balance responses to simulated zero-gravity, measurements were made in six subjects before and during -5 deg continuous head-down bed rest (HDBR) over 8 d at 10,678 ft. The same subjects were studied again at this altitude without HDBR as a control (CON) using a cross-over design. During this time, they maintained normal upright day-time activities, sleeping in the horizontal position at night. Fluid balance changes during HDBR in hypoxia were more pronounced than similar measurements previously reported from HDBR studies at sea level. Plasma volume loss was slightly greater and the diuresis and natriuresis were doubled in magnitude as compared to previous studies in normoxia and sustained for 4 d during hypoxia. These changes were associated with an immediate but transient rise in plasma atrial natriuretic peptide (ANP) to day 4 of 140 percent in HDBR and 41 percent in CON (p less than 0.005), followed by a decline towards baseline. Differences were less striking between HDBR and CON for plasma antidiuretic hormone and aldosterone, which were transiently reduced by HDBR. Plasma catecholamines showed a similar pattern to ANP in both HDBR and CON, suggesting that elevated ANP and catecholamines together accounted for the enhanced fluid shifts with HDBR during hypoxia.

  17. Circulating fluidized bed hydrodynamics experiments for the multiphase fluid dynamics research consortium (MFDRC).

    SciTech Connect

    Oelfke, John Barry; Torczynski, John Robert; O'Hern, Timothy John; Tortora, Paul Richard; Bhusarapu, Satish; Trujillo, Steven Mathew

    2006-08-01

    An experimental program was conducted to study the multiphase gas-solid flow in a pilot-scale circulating fluidized bed (CFB). This report describes the CFB experimental facility assembled for this program, the diagnostics developed and/or applied to make measurements in the riser section of the CFB, and the data acquired for several different flow conditions. Primary data acquired included pressures around the flow loop and solids loadings at selected locations in the riser. Tomographic techniques using gamma radiation and electrical capacitance were used to determine radial profiles of solids volume fraction in the riser, and axial profiles of the integrated solids volume fraction were produced. Computer Aided Radioactive Particle Tracking was used to measure solids velocities, fluxes, and residence time distributions. In addition, a series of computational fluid dynamics simulations was performed using the commercial code Arenaflow{trademark}.

  18. High temperature fluid-bed heat recovery for aluminum melting furnace

    SciTech Connect

    1982-12-01

    The objective of the study was to establish whether technical problems would be encountered in increasing the inlet temperature of the fluid bed heat exchanger unit at Alcoa above the 1100/sup 0/F target of the current contract. Specifically, the temperature range of up to, and potentially above, 1600/sup 0/F were investigated to establish the benefits of higher temperature, trade offs required, and plans to achieve that technology goal. The benefits are tabulated and are very significant, particularly at the temperature range of 1600 to 1800/sup 0/F. Relative to 1100/sup 0/F the heat recovery is increased by 24 to 29% at 1600 and 1800/sup 0/F respectively.

  19. Coupling scales for modelling heavy metal vaporization from municipal solid waste incineration in a fluid bed by CFD.

    PubMed

    Soria, José; Gauthier, Daniel; Flamant, Gilles; Rodriguez, Rosa; Mazza, Germán

    2015-09-01

    Municipal Solid Waste Incineration (MSWI) in fluidized bed is a very interesting technology mainly due to high combustion efficiency, great flexibility for treating several types of waste fuels and reduction in pollutants emitted with the flue gas. However, there is a great concern with respect to the fate of heavy metals (HM) contained in MSW and their environmental impact. In this study, a coupled two-scale CFD model was developed for MSWI in a bubbling fluidized bed. It presents an original scheme that combines a single particle model and a global fluidized bed model in order to represent the HM vaporization during MSW combustion. Two of the most representative HM (Cd and Pb) with bed temperatures ranging between 923 and 1073K have been considered. This new approach uses ANSYS FLUENT 14.0 as the modelling platform for the simulations along with a complete set of self-developed user-defined functions (UDFs). The simulation results are compared to the experimental data obtained previously by the research group in a lab-scale fluid bed incinerator. The comparison indicates that the proposed CFD model predicts well the evolution of the HM release for the bed temperatures analyzed. It shows that both bed temperature and bed dynamics have influence on the HM vaporization rate. It can be concluded that CFD is a rigorous tool that provides valuable information about HM vaporization and that the original two-scale simulation scheme adopted allows to better represent the actual particle behavior in a fluid bed incinerator. PMID:26050934

  20. Longitudinal Multistage Testing

    ERIC Educational Resources Information Center

    Pohl, Steffi

    2013-01-01

    This article introduces longitudinal multistage testing (lMST), a special form of multistage testing (MST), as a method for adaptive testing in longitudinal large-scale studies. In lMST designs, test forms of different difficulty levels are used, whereas the values on a pretest determine the routing to these test forms. Since lMST allows for…

  1. Taste masking of naproxen sodium granules by fluid-bed coating.

    PubMed

    Stange, Ulrike; Führling, Christian; Gieseler, Henning

    2014-03-01

    The taste of oral dosage forms is an important argument regarding patient's compliance and acceptability. For this reason, it is often necessary to mask an undesirable and unpleasant taste of an active pharmaceutical ingredient. The purpose of this study was to mask the taste of naproxen sodium by a new fluid-bed coating approach. Different compositions of coating suspensions were used to coat naproxen sodium granules. It was found that products with the addition of a plasticizer were not stable at 40 °C and tended to agglomerate. Subsequently, formulations without plasticizer were used and the ratio between water and Eudragit® E was varied. Increasing the fraction of water in the suspension from 3% to 14% reduced the effective release of naproxen sodium. An optimum ratio between naproxen sodium granules and Eudragit® E was found to be 1:1.576, where less naproxen sodium was released than the threshold bitter value and an appropriate taste masking for more than 5 min was guaranteed. Investigation of the particle size distribution revealed a d(10) of 138.35 ± 21.52 µm, a d(50 )= 256.40 ± 11.27 µm and a d(90 )= 500.85 ± 69.08 µm, which guarantees an acceptable mouthfeel for patients. PMID:23324020

  2. Optimization and scale-up of a fluid bed tangential spray rotogranulation process.

    PubMed

    Bouffard, J; Dumont, H; Bertrand, F; Legros, R

    2007-04-20

    The production of pellets in the pharmaceutical industry generally involves multi-step processing: (1) mixing, (2) wet granulation, (3) spheronization and (4) drying. While extrusion-spheronization processes have been popular because of their simplicity, fluid-bed rotogranulation (FBRG) is now being considered as an alternative, since it offers the advantages of combining the different steps into one processing unit, thus reducing processing time and material handling. This work aimed at the development of a FBRG process for the production of pellets in a 4.5-l Glatt GCPG1 tangential spray rotoprocessor and its optimization using factorial design. The factors considered were: (1) rotor disc velocity, (2) gap air pressure, (3) air flow rate, (4) binder spray rate and (5) atomization pressure. The pellets were characterized for their physical properties by measuring size distribution, roundness and flow properties. The results indicated that: pellet mean particle size is negatively affected by air flow rate and rotor plate speed, while binder spray rate has a positive effect on size; pellet flow properties are enhanced by operating with increased air flow rate and worsened with increased binder spray rate. Multiple regression analysis enabled the identification of an optimal operating window for production of acceptable pellets. Scale-up of these operating conditions was tested in a 30-l Glatt GPCG15 FBRG. PMID:17166677

  3. Catalytic ozonation of phenolic wastewater with activated carbon fiber in a fluid bed reactor.

    PubMed

    Qu, Xianfeng; Zheng, Jingtang; Zhang, Yanzong

    2007-05-15

    The effect of activated carbon fiber (ACF) on the ozonation of phenol in water in a fluid bed reactor was investigated. It was observed that this combined process could increase the yield of the oxidation process significantly for phenol and COD (chemical oxygen demand) removal, especially for the phenol removal. The efficiency of ozonation increased with an increase in the dose of ACF. Higher initial phenol concentration only caused a slight decrease of phenol and COD removal. The results of repeated use found that ozonation could efficiently regenerate ACF in situ in the reactor, which was considered easy to handle without the costly ex situ regeneration of the industrial treatment process. The Boehm titrations and FTIR studies indicate that the ozonation process in water can significantly change the composition of acidic surface oxygen-containing groups of ACF, leading to the increase of carboxylic, hydroxylic, and carbonylic groups and the slight decrease of the lactonic groups. Furthermore, this process can also increase the surface area and total pore volume of ACF. Due to the new micropore formation and some pore enlargement, the micropores became smaller, and the mesopores and macropores got bigger. PMID:17336995

  4. Fluid-particle interaction in turbulent open channel flow with fully-resolved mobile beds

    NASA Astrophysics Data System (ADS)

    Vowinckel, Bernhard; Kempe, Tobias; Fröhlich, Jochen

    2014-10-01

    The paper presents Direct Numerical Simulations of an open channel flow laden with spherical particles at a bulk Reynolds number of 2941. The transport of thousands of mobile particles is simulated propagating over a rough bed which consists of immobile particles of the same size in hexagonal ordering. An Immersed Boundary Method is used for the numerical representation of the particles. With 22 points per diameter even the viscous scales of the flow are resolved at this Reynolds number. The reference run contains just as many fixed as mobile particles with a relative density slightly above the nominal threshold of incipient motion. Further runs were conducted with decreased mass loading and decreased Shields number together with a simulation containing only immobile particles. The variation of the parameters defining the mobile sediment yields a strong modification of particle-fluid as well as particle-particle interactions yielding different structures in space and time. This is assessed by means of appropriate statistical quantities addressing the continuous and the disperse phase. The results are in qualitative agreement with experimental observations at higher Reynolds number.

  5. Development and evaluation of diltiazem hydrochloride controlled-release pellets by fluid bed coating process

    PubMed Central

    Prasad, Mikkilineni Bhanu; Vidyadhara, Suryadevara; Sasidhar, Reddyvalam Lankapalli C.; Balakrishna, Talamanchi; Trilochani, Pavuluri

    2013-01-01

    The aim of the present study was to develop controlled-release pellets of diltiazem HCl with ethyl cellulose and hydroxylpropyl methylcellulose phthalate as the release rate retarding polymers by fluid bed coating technique. The prepared pellets were evaluated for drug content, particle size, subjected to Scanning Electron Microscopy (SEM) and Differential Scanning Calori metry (DSC), and evaluated for in vitro release. Stability studies were carried out on the optimized formulations for a period of 3 months. The drug content was in the range of 97%-101%. The mean particle size of the drug-loaded pellets was in the range 700-785 μm. The drug release rate decreased as the concentration of ethyl cellulose increased in the pellet formulations. Among the prepared formulations, FDL10 and FDL11 showed 80% drug release in 16 h, matching with USP dissolution test 6 for diltiazem HCl extended-release capsules. SEM photographs confirmed that the prepared formulations were spherical in nature with a smooth surface. The compatibility between drug and polymers in the drug-loaded pellets was confirmed by DSC studies. Stability studies indicated that the pellets were stable. PMID:23833750

  6. Development of a fluid bed granulation design space using critical quality attribute weighted tolerance intervals.

    PubMed

    Zacour, Brian M; Drennen, James K; Anderson, Carl A

    2012-08-01

    The fluid bed granulation and drying unit operation were used as a case study for control systems implementation. This single processor was used to blend, granulate, dry, and cool the materials. The current study demonstrated control of each of the phases using a fully automated, hybrid control system that incorporated first-principle modeling, empirical design of experiments (DOE), and process analytical technology to assure the production of constant product quality. The system allowed data to be collected efficiently for the development of a rigorous design space that combined formulation factors, process factors, and their interactions to define a tolerance surface where risk of future product failure was significantly reduced. The DOE incorporated microcrystalline cellulose and lactose monohydrate, excipients with substantially different wetting properties, to elucidate the relationship between the critical process parameters of the unit operation and the material properties of the formulation components. The extended analysis of covariance model enabled these factors and their interaction terms to be described in a single model. The results indicate that the development of a tolerance interval-based weighted design space can enhance product understanding and thereby help to assure future product quality. PMID:22570275

  7. Cardiovascular and Body Fluid Adjustments During Bed Rest and Space Flight

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.; Tomko, David L. (Technical Monitor)

    1995-01-01

    Although a few scientific bed rest (BR) studies were conducted soon after World War II, advent of the space program provided impetus for utilizing prolonged (days-months) BR, which employed the horizontal or 6 degree head-down tilt (HDT) body positions, to simulate responses of healthy people to microgravity. Shorter (hours) HDT protocols were used to study initial mechanisms of the acclimation-deconditioning (reduction of physical fitness) syndromes. Of the major physiological factors modified during BR, reduced force on bones, ligaments, and muscles, and greatly reduced hydrostatic pressure within the cardiovascular system, the latter: which involves shifts of blood from the lower extremities into the upper body, increase in central venous pressure, and diuresis, appears to be the initial stimulus for acclimation. Increase in central venous pressure occurs in subjects during weightless parabolic flight, but not in astronauts early during orbital flight. But significant reduction in total body water (hypohydration) and plasma volume (hypovolemia) occurs in subjects during both BR and microgravity. Response of interstitial fluid volume is not as clear, It has been reported to increase during BR, and it may have increased in Skylab II and IV astronauts. Reduction of total body water, and greater proportional reduction of extracellular volume, indicates increased cellular volume which may contribute to inflight cephalic edema. Cerebral pressure abates after a few days of HDT, but not during flight. accompanied by normal (eugravity) blood constituent concentrations suggesting some degree of acclimation had occurred. But during reentry, with moderately increased +Gz (head-to-foot) acceleration and gravitational force, the microgravity "euhydration" becomes functional progressive dehydration contributing to the general reentry syndrome (GRS) which, upon landing the Shuttle, can and often results in gastrointestinal distress, disorientation, vertigo, fatigue, and

  8. Fluid bed gasification – Plasma converter process generating energy from solid waste: Experimental assessment of sulphur species

    SciTech Connect

    Morrin, Shane; Lettieri, Paola; Chapman, Chris; Taylor, Richard

    2014-01-15

    Highlights: • We investigate gaseous sulphur species whilst gasifying sulphur-enriched wood pellets. • Experiments performed using a two stage fluid bed gasifier – plasma converter process. • Notable SO{sub 2} and relatively low COS levels were identified. • Oxygen-rich regions of the bed are believed to facilitate SO{sub 2}, with a delayed release. • Gas phase reducing regions above the bed would facilitate more prompt COS generation. - Abstract: Often perceived as a Cinderella material, there is growing appreciation for solid waste as a renewable content thermal process feed. Nonetheless, research on solid waste gasification and sulphur mechanisms in particular is lacking. This paper presents results from two related experiments on a novel two stage gasification process, at demonstration scale, using a sulphur-enriched wood pellet feed. Notable SO{sub 2} and relatively low COS levels (before gas cleaning) were interesting features of the trials, and not normally expected under reducing gasification conditions. Analysis suggests that localised oxygen rich regions within the fluid bed played a role in SO{sub 2}’s generation. The response of COS to sulphur in the feed was quite prompt, whereas SO{sub 2} was more delayed. It is proposed that the bed material sequestered sulphur from the feed, later aiding SO{sub 2} generation. The more reducing gas phase regions above the bed would have facilitated COS – hence its faster response. These results provide a useful insight, with further analysis on a suite of performed experiments underway, along with thermodynamic modelling.

  9. The effect of powder type, free moisture and deformation behaviour of granules on the kinetics of fluid-bed granulation.

    PubMed

    Abberger, T

    2001-11-01

    The effects of two types of powder, lactose and corn starch, and of free moisture on the kinetics of fluid-bed granulation have been investigated using population balance modelling. A coalescence kernel that considered the deformation behaviour of the granules was used. The best fit of the experimental data was obtained for both materials by assuming that the granules underwent plastic deformation. The predicted cumulative number fractions were in very good agreement with the experimental data. The effect of free moisture (in the range of 5-10%) was investigated with lactose. The process was independent of the statistical distribution in free moisture within the approximate range 5-10%. The results suggest a local plasticity in fluid-bed spray granulation caused by the deposition of spray droplets onto the granules, with their subsequent absorption into the voids leading to regions of saturated voids. PMID:11677075

  10. Integrated low emissions cleanup system for direct coal fueled turbines (moving bed, fluid bed contactor/ceramic filter)

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1992-10-20

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meat this technical challenge: a baseline ceramic barrier filter ILEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300[degree]F. This document reports the status of a program in the nineteenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.

  11. Integrated low emissions cleanup system for direct coal fueled turbines (Moving bed, fluid bed contactor/ceramic filter)

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1992-01-20

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge: a baseline ceramic barrier filter ILEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300{degrees}F. This document reports the status of a program in the seventeenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.

  12. Study of ebullated bed fluid dynamics for H-Coal. Quarterly progress report No. 1, July 1-September 30, 1980

    SciTech Connect

    Schaefer, R. J.; Rundell, D. N.

    1980-12-01

    Cold flow experiments were completed with kerosene, nitrogen, and HDS-2A (3/16'' length) catalyst. Percent bed expansion, gas/liquid/catalyst holdups, and drift fluxes were determined for each test. Fluid dynamics data were obtained at HRI during Run PDU-10 (Wyodak coal and Amocat-1A catalyst). Reactor liquid samples were taken for later viscosity determination. A 6'' diameter test stand for bubble coalescence experiments was constructed and delivered to Northwestern University. A search was initiated to select suitable model fluids.

  13. Formulation and stability evaluation of ketoprofen sustained-release tablets prepared by fluid bed granulation with Carbopol 971P solution.

    PubMed

    Vaithiyalingam, S R; Tuliani, P; Wilber, W; Reddy, I K; Khan, M A

    2002-11-01

    The objectives of the present study were: (1) to investigate the possibility of using a Carbopol polymeric solution as granulating agent by the fluid bed granulating process; (2) to select a suitable method of tabletting for sustaining the release of ketoprofen for 12 hr; (3) to perform stability studies according to International Committee on Harmonization (ICH) guidelines and photostability on ketoprofen SR tablets; (4) to study the influence of the storage conditions on release kinetics and melting endotherm of ketoprofen; and (5) to predict the shelf-life of the ketoprofen SR tablets. Tabletting ingredients were ketoprofen, anhydrous dicalcium phosphate, Carbopol 971P, talc, and magnesium stearate. Carbopol 971P solution (0.8% w/v) was used as a granulating solution in the fluid bed granulator. For comparative evaluation, tablets were also prepared by direct compression and wet granulation, and subjected to dissolution. Tablets prepared by fluid bed granulation technique were stored in incubators maintained at 37, 40, 50, and 60 degrees C, 40 degrees C/75% RH, 30 degrees C/60% RH, and 25 degrees C/60% RH, and in a light chamber with light intensity of 600 ft candle at 25 degrees C. Melting endotherms were obtained for the drug as well as the tablets during stability studies by differential scanning calorimetry. Tablets prepared by fluid bed granulation technique prolonged the release of ketoprofen better than tablets obtained by direct compression and wet granulation. Further, it complied with the requirements of ICH guidelines for stability testing. Higher temperature and humidity (40 +/- 2 degrees C/75% RH, 40 degrees C, 50 degrees C, and 60 degrees C) adversely affected the rate and extent of the dissolution. Ketoprofen SR tablets stored in amber-colored bottles demonstrated a good photostability for 6 months at 600 ft candle. The shelf-life of the formulation was predicted as 32 months. PMID:12476869

  14. Improving design and operation of multiple-hearth and fluid bed sludge incinerators. Final report, June 1984-September 1985

    SciTech Connect

    Not Available

    1986-07-01

    The purpose of the investigation is to document improvements in design, operation, and maintenance of multiple-hearth and fluid-bed furnace incineration for combustion of sludge in municipal wastewater-treatment plants. The information contained in the report is intended to supplement and qualify information available from incinerator manufacturers and published literature. The report addresses incinerator and support systems design deficiencies and solutions, operation and maintenance problems and solutions, fuel efficient operation, upgrading of existing incinerators, administration, and personnel training.

  15. In-line monitoring of particle size in a fluid bed granulator: investigations concerning positioning and configuration of the sensor.

    PubMed

    Roßteuscher-Carl, Katrin; Fricke, Sabine; Hacker, Michael C; Schulz-Siegmund, Michaela

    2014-05-15

    According to the ICH Q8 guideline, analytic technologies (PAT) are important tools for characterization and optimization of pharmaceutical manufacturing processes. Particle size as a critical quality attribute for granules is therefore an important parameter that should be monitored during the fluid bed granulation process. This work focusses on optimizing position and configuration of an SFT-sensor for the in-line measurement of particle size distribution in a Glatt GPCG 3 fluid bed granulator. As model-substances, different grades of microcrystalline cellulose were used. The in-line measured particle size and particle rate in the sensor were evaluated. A sensor position in the deceleration zone of the granulator was found to be promising for in-line particle size measurement. Most reliable data were generated in this position when the probe was placed in a distance of 11cm from the chamber wall to avoid bias by the inlet air stream. No major influence of rotation angle of the probe was found in this position. Furthermore, an entire fluid bed granulation process was successfully monitored with the sensor installed in the optimized setting. PMID:24589125

  16. Drug loaded and ethylcellulose coated mesoporous silica for controlled drug release prepared using a pilot scale fluid bed system.

    PubMed

    Hacene, Youcef Chakib; Singh, Abhishek; Van den Mooter, Guy

    2016-06-15

    The goal of this study was to test the feasibility to load non-ordered, non-spherical mesoporous silica with the model drug paracetamol, and subsequently coat the loaded particles using one single pilot scale fluid bed system equipped with a Wurster insert. Mesoporous silica particles (Davisil(®)) with a size ranging from 310 to 500μm and an average pore diameter of 15nm were loaded with paracetamol to 18.8% drug content. Subsequently, loaded cores were coated with ethylcellulose to obtain controlled drug release. Coating processing variables were varied following a full factorial design and their effect on drug release was assessed. Increasing coating solution feed rate and decreasing fluidizing air temperature were found to increase drug release rates. Increasing pore former level and decreasing coating level were found to increase drug release rates. The release medium's osmolality was varied using different sodium chloride concentrations, which was found to affect drug release rates. The results of this study clearly indicate the potential of non-ordered, non-spherical mesoporous silica as a reservoir carrier for the controlled release of drugs. Although non-spherical, we were able to reproducibly coat this carrier using a bottom spray fluid bed system. However, a major hurdle that needs to be tackled is the attrition the material suffers from during fluid bed processing. PMID:27107901

  17. Microencapsulation of fish oil by spray granulation and fluid bed film coating.

    PubMed

    Anwar, Sri Haryani; Weissbrodt, Jenny; Kunz, Benno

    2010-08-01

    The stability of microencapsulated fish oil prepared with 2 production processes, spray granulation (SG) and SG followed by film coating (SG-FC) using a fluid bed equipment, was investigated. In the 1st process, 3 types of fish oil used were based on the ratios of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (10/50, 33/22, and 18/12). Each type was emulsified with soluble soybean polysaccharide (SSPS) and maltodextrin to produce 25% oil powders. In the 2nd process, 15% film coating of hydroxypropyl betacyclodextrin (HPBCD) was applied to the granules from the 1st process. The powder stability against oxidation was examined by measurement of peroxide values (PV) and headspace propanal after storage at room temperature and at 3 to 4 degrees C for 6 wk. Uncoated powder containing the lowest concentration of PUFA (18/12) was found to be stable during storage at room temperature with maximum PV of 3.98 +/- 0.001 meq/kg oil. The PV increased sharply for uncoated powder with higher concentration of omega-3 (in 33/22 and 10/50 fish oils) after 3 wk storage. The PVs were in agreement with the concentration of propanal, and these 2 parameters remained constant for most of the uncoated powders stored at low temperature. Unexpectedly, the outcomes showed that the coated powders had lower stability than uncoated powders as indicated by higher initial PVs; more hydroperoxides were detected as well as increasing propanal concentration. The investigation suggests that the film-coating by HPBCD ineffectively protected fish oil as the coating process might have induced further oxidation; however, SG is a good method for producing fish oil powder and to protect it from oxidation because of the "onion skin" structure of granules produced in this process. PMID:20722921

  18. Combustor with multistage internal vortices

    DOEpatents

    Shang, Jer Yu; Harrington, R.E.

    1987-05-01

    A fluidized bed combustor is provided with a multistage arrangement of vortex generators in the freeboard area. The vortex generators are provided by nozzle means which extend into the interior of the freeboard for forming vortices within the freeboard areas to enhance the combustion of particulate material entrained in product gases ascending into the freeboard from the fluidized bed. Each of the nozzles are radially inwardly spaced from the combustor walls defining the freeboard to provide for the formation of an essentially vortex-free, vertically extending annulus about the vortices whereby the particulate material centrifuged from the vortices against the inner walls of the combustor is returned through the annulus to the fluidized bed. By adjusting the vortex pattern within the freeboard, a significant portion of the full cross-sectional area of the freeboard except for the peripheral annulus can be contacted with the turbulent vortical flow for removing the particulate material from the gaseous products and also for enhancing the combustion thereof within the freeboard. 2 figs.

  19. Combustor with multistage internal vortices

    DOEpatents

    Shang, Jer Y.; Harrington, Richard E.

    1989-01-01

    A fluidized bed combustor is provided with a multistage arrangement of vortex generators in the freeboard area. The vortex generators are provided by nozzle means which extend into the interior of the freeboard for forming vortices within the freeboard area to enhance the combustion of particulate material entrained in product gases ascending into the freeboard from the fluidized bed. Each of the nozzles are radially inwardly spaced from the combustor walls defining the freeboard to provide for the formation of an essentially vortex-free, vertically extending annulus about the vortices whereby the particulate material centrifuged from the vortices against the inner walls of the combustor is returned through the annulus to the fluidized bed. By adjusting the vortex pattern within the freeboard, a significant portion of the full cross-sectional area of the freeboard except for the peripheral annulus can be contacted with the turbulent vortical flow for removing the particulate material from the gaseous products and also for enhancing the combustion thereof within the freeboard.

  20. Integrated low emissions cleanup system for direct coal fueled turbines (moving bed, fluid bed contactor/ceramic filter)

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1992-04-20

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge: a baseline ceramic barrier filter nEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300[degrees]F. This document reports the status of a program in the eighteenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.

  1. Quantifying fluid and bed dynamics for characterizing benthic physical habitat in large rivers

    USGS Publications Warehouse

    Gaeuman, D.; Jacobson, R.B.

    2007-01-01

    Sturgeon use benthic habitats in and adjacent to main channels where environmental conditions can include bedload sediment transport and high near-bed flow velocities. Bed velocity measurements obtained with acoustic Doppler instruments provide a means to assess the concentration and velocity of sediment moving near the streambed, and are thus indicative of the bedload sediment transport rate, the near-bed flow velocity, and the stability of the substrate. Acoustic assessments of benthic conditions in the Missouri River were conducted at scales ranging from the stream reach to individual bedforms. Reach-scale results show that spatially-averaged bed velocities in excess of 0.5 m s-1 frequently occur in the navigation channel. At the local scale, bed velocities are highest near bedform crests, and lowest in the troughs. Low-velocity zones can persist in areas with extremely high mean bed velocities. Use of these low-velocity zones may allow sturgeon to make use of portions of the channel where the average conditions near the bed are severe. To obtain bed velocity measurements of the highest possible quality, it is necessary to extract bottom-track and GPS velocity information from the raw ADCP data files on a ping-by-ping basis. However, bed velocity measured from a point can also be estimated using a simplified method that is more easily implemented in the context of routine monitoring. The method requires only the transect distance and direction data displayed in standard ADCP data-logging software. Bed velocity estimates obtained using this method are usually within 5-10% of estimates obtained from ping-by-ping processing. ?? 2007 Blackwell Verlag.

  2. Integrated low emissions cleanup system for direct coal fueled turbines (moving bed, fluid bed contactor/ceramic filter). Twenty-ninth quarterly status report, October--December 1994

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.

    1996-02-01

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of advanced, coal-fueled turbine power plants such as pressurized fluid bed combustion and coal gasification combined cycles. A major technical challenge remaining for the development of the coal-fueled turbine is high-temperature gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure process gases. This document reports the status of a program in the twenty-seventh quarter to develop this ILEC technology.

  3. Integrated low emissions cleanup system for direct coal fueled turbines (moving bed, fluid bed contactor/ceramic filter). Twenty-seventh quarterly status report, April--June 1994

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1994-10-01

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of advanced, coal-fueled turbine power plants such as pressurized fluid bed combustion and coal gasification combined cycles. A major technical challenge remaining for the development of the coal-fueled turbine is high-temperature gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure process gases. This document reports the status of a program in the twenty-seventh quarter to develop this ILEC technology.

  4. Factorial design in the spheronization of ibuprofen microparticulates using the rotor disk fluid-bed technology.

    PubMed

    Chukwumezie, Beatrice Nkem; Wojcik, Mark; Malak, Paul; Damico, Frank; Adeyeye, Moji Christianah

    2004-01-01

    The aim of this study was to statistically evaluate the effects of some formulation and process variables in the spheronization of microparticulates of ibuprofen using the rotor disk fluid-bed technology and water as binder. Preliminary studies revealed that presence of surfactant, plate material type, and nature and content of binder influenced the process and quality of the spheronized material. A 2 x 2 x 3 full factorial randomized experiment was designed, demonstrating the influence of these factors on properties such as percent yield, particle size distribution, densities, ibuprofen release, moisture content, etc., as well as their interactions in the experimental response. A response known as the usable fraction was created representing microparticulates of 250 to 850 microm sizes (mesh size 20-60). The reproducibility of the spheronization process was assessed by blocking the experiments with the experiments within the blocks randomly replicated. The main effects included two binder levels (X1), two surfactant levels (X2), and a three-level plate type (X3) in which 2 two-level factors were collapsed into a single three-level factor. The results from the statistical analysis (general linear model, JMP 4) showed that the variables studied had a significant influence on most of the response variables evaluated (p < 0.05), with the binder level proving to be the most significant of the three. There was also significant interaction (p<0.05) between binder level and plate type with the drug content, friability, sphericity, loss on drying (LOD), and usable fraction response variables, and between the binder and the surfactant levels with the drug content, Q20, true density, geometric mean diameter, LOD, and usable fraction responses. High levels of surfactant and binder increased the sphere size, while low levels decreased it. Significant (p < 0.05) interaction was also observed between the plate type and surfactant level with the drug content, geometric mean

  5. CHEMICALLY ACTIVE FLUID BED FOR SOX CONTROL. VOLUME I. PROCESS EVALUATION STUDIES

    EPA Science Inventory

    The report describes selected process evaluation studies supporting the development of an atmospheric-pressure, fluidized-bed, chemically active gasification process, using a regenerative limestone sulfur sorbent to produce low- to intermediate-Btu fuel gas. Limestone sorbent sel...

  6. Solid self-nanoemulsifying cyclosporin A pellets prepared by fluid-bed coating: preparation, characterization and in vitro redispersibility

    PubMed Central

    Lei, Yang; Lu, Yi; Qi, Jianping; Nie, Sufang; Hu, Fuqiang; Pan, Weisan; Wu, Wei

    2011-01-01

    Background: The objective of this study was to evaluate fluid-bed coating as a new technique to prepare a pellet-based solid self-nanoemulsifying drug delivery system (SNEDDS) using cyclosporin A as a model of a poorly water-soluble drug. Methods: The rationale of this technique was to entrap a Liquid SNEDDS in the matrix of the coating material, polyvinylpyrrolidone K30, by fluid-bed coating. Pseudoternary phase diagrams were used to screen the liquid SNEDDS formulations. The optimal formulation was composed of Labrafil M® 1944 CS, Transcutol P®, and Cremophor® EL in a ratio of 9:14:7. To prepare solid SNEDDS pellets, liquid SNEDDS was first dispersed in an aqueous solution of polyvinylpyrrolidone and then sprayed onto the surface of non-pareil pellets. Upon evaporation of water, polyvinylpyrrolidone precipitated and formed tight films to entrap the liquid SNEDDS. Visual observation and scanning electron microscopic analysis confirmed good appearance of the solid SNEDDS pellets. Results: Our results indicated that up to 40% of the liquid SNEDDS could be entrapped in the coating layer. Powder x-ray diffraction analysis confirmed nonexistence of crystalline cyclosporin A in the formulation. Solid SNEDDS pellets showed a slower redispersion rate than the liquid SNEDDS. An increase in the total liquid SNEDDS loading led to faster redispersion, whereas increased coating weight (up to 400%) significantly decreased the redispersion rate. Both cyclosporin A loading and protective coating with 5% polyvinylpyrrolidone K30 did not significantly affect the redispersion rate. Conclusion: It is concluded that fluid-bed coating is a new technique with considerable potential for preparation of pellet-based solid SNEDDS formulations. PMID:21589647

  7. Multistage deformation of Au-quartz veins (Laurieras, French Massif Central): evidence for late gold introduction from microstructural, isotopic and fluid inclusion studies

    NASA Astrophysics Data System (ADS)

    Essarraj, S.; Boiron, M.-C.; Cathelineau, M.; Fourcade, S.

    2001-07-01

    The relative chronology of fluid migration, quartz and Au-deposition in a silicified fault from the main Au-district (Laurieras, St Yrieix district) from northern French Massif Central has been determined from microstructural, fluid inclusion, isotopic and ore mineral evidences. Three main stages of fluid circulation, microfracturing and quartz crystallization, and ore deposition were distinguished on the basis of textural relationships and the pressure, temperature and composition of the palaeo-fluids: (1) a series of early fluid events was responsible for the localized drainage of retrograde metamorphic fluids along the main fault and the subsequent sealing by milky and microcrystalline quartz preceeded the main Au-ore stages. Early fluids were aqueous-carbonic, trapped under lithostatic to sublithostatic pressures at temperatures in the range 350-500°C. Subsequently, several types of microstructures were developed in the early quartz matrix. (2) NS microfractures filled by clear quartz, arsenopyrite and boulangerite (I) contain significant refractory gold concentrations. Clear quartz formed from aqueous-carbonic fluids of lower densities than those of the earlier fluids. Significant pressure drops, down to pressures around 55 MPa were responsible for a local immiscibility of the aqueous-carbonic fluids at temperatures of 340±20°C. (3) The main ore stage is characterized by the formation of dense sets of sub-vertical (EW) microfractures, healed fluid inclusion planes in quartz, and filled by ore minerals (native gold, galena and boulangerite II) when they crosscut earlier sulfides. The fluids are aqueous with low and decreasing salinity, and probable trapping temperatures around 230°C. Isotopic data, obtained on microfissured quartz, indicate these dilute aqueous fluids may be considered as meteoric waters that deeply infiltrated the crust. Late microfissuring of a mesothermal quartz vein, originally barren (only with pyrite and arsenopyrite), appears to be

  8. Fluid bed gasification--plasma converter process generating energy from solid waste: experimental assessment of sulphur species.

    PubMed

    Morrin, Shane; Lettieri, Paola; Chapman, Chris; Taylor, Richard

    2014-01-01

    Often perceived as a Cinderella material, there is growing appreciation for solid waste as a renewable content thermal process feed. Nonetheless, research on solid waste gasification and sulphur mechanisms in particular is lacking. This paper presents results from two related experiments on a novel two stage gasification process, at demonstration scale, using a sulphur-enriched wood pellet feed. Notable SO2 and relatively low COS levels (before gas cleaning) were interesting features of the trials, and not normally expected under reducing gasification conditions. Analysis suggests that localised oxygen rich regions within the fluid bed played a role in SO2's generation. The response of COS to sulphur in the feed was quite prompt, whereas SO2 was more delayed. It is proposed that the bed material sequestered sulphur from the feed, later aiding SO2 generation. The more reducing gas phase regions above the bed would have facilitated COS--hence its faster response. These results provide a useful insight, with further analysis on a suite of performed experiments underway, along with thermodynamic modelling. PMID:24176239

  9. Two-compartmental population balance modeling of a pulsed spray fluidized bed granulation based on computational fluid dynamics (CFD) analysis.

    PubMed

    Liu, Huolong; Li, Mingzhong

    2014-11-20

    In this work a two-compartmental population balance model (TCPBM) was proposed to model a pulsed top-spray fluidized bed granulation. The proposed TCPBM considered the spatially heterogeneous granulation mechanisms of the granule growth by dividing the granulator into two perfectly mixed zones of the wetting compartment and drying compartment, in which the aggregation mechanism was assumed in the wetting compartment and the breakage mechanism was considered in the drying compartment. The sizes of the wetting and drying compartments were constant in the TCPBM, in which 30% of the bed was the wetting compartment and 70% of the bed was the drying compartment. The exchange rate of particles between the wetting and drying compartments was determined by the details of the flow properties and distribution of particles predicted by the computational fluid dynamics (CFD) simulation. The experimental validation has shown that the proposed TCPBM can predict evolution of the granule size and distribution within the granulator under different binder spray operating conditions accurately. PMID:25181553

  10. Local CFD kinetic model of cadmium vaporization during fluid bed incineration of municipal solid waste.

    PubMed

    Soria, J; Gauthier, D; Falcoz, Q; Flamant, G; Mazza, G

    2013-03-15

    The emissions of heavy metals during incineration of Municipal Solid Waste (MSW) are a major issue to health and the environment. It is then necessary to well quantify these emissions in order to accomplish an adequate control and prevent the heavy metals from leaving the stacks. In this study the kinetic behavior of Cadmium during Fluidized Bed Incineration (FBI) of artificial MSW pellets, for bed temperatures ranging from 923 to 1073 K, was modeled. FLUENT 12.1.4 was used as the modeling framework for the simulations and implemented together with a complete set of user-defined functions (UDFs). The CFD model combines the combustion of a single solid waste particle with heavy metal (HM) vaporization from the burning particle, and it takes also into account both pyrolysis and volatiles' combustion. A kinetic rate law for the Cd release, derived from the CFD thermal analysis of the combusting particle, is proposed. The simulation results are compared with experimental data obtained in a lab-scale fluidized bed incinerator reported in literature, and with the predicted values from a particulate non-isothermal model, formerly developed by the authors. The comparison shows that the proposed CFD model represents very well the evolution of the HM release for the considered range of bed temperature. PMID:23410804

  11. Performance improvement of a converted fluid bed boiler (from traveling grate type) for agro waste combustion -- A case study

    SciTech Connect

    Sethumadhavan, R.; Karthikeyan, G.; Raviprakash, A.V.; Vasudevan, R.

    1997-12-31

    This paper investigates the operational difficulty encountered while operating a fluid bed boiler--which was earlier serving with a traveling grate for agrowaste combustion. This boiler, although operating on fluid bed technology principle, could not produce required combustion efficiency while burning any of the agrowastes such as rice husk, de-oiled bran, ground nut shell, etc. While carrying out the performance assessment study, it was found that, this inefficient combustion was mainly due to the improper operating parameters and partly due to incorrect furnace configuration. The drawbacks of the system have been attended to and set right incurring a very minor expenditure. This has led to an annual fuel saving of approximately US $40,000. The major results achieved are: (1) boiler thermal efficiency increased from 66--73%; (2) boiler was loaded uniformly and on-time operation has increased to 100% from earlier 60%; (3) boiler shut down time due to operational problems has come down from 35 hours per month to 15 hours per month; (4) very effective dust collection system was achieved resulting in reduced ID fan erosion; and (5) an annual saving of US $100,000 (both direct and indirect) was achieved.

  12. 10,000 hours commercial operating experience with advanced-design, reflux circulating fluid bed scrubbing employing slaked lime reagent

    SciTech Connect

    Graf, R.E.; Huckriede, B.W.

    1995-06-01

    Details are presented of design, operating and maintenance experience with a commercial installation in Germany of a circulating fluid bed scrubber of advanced design (Reflux Circulating Fluid Bed Scrubber utilizing slaked lime slurry) retrofitted to a pulverized coal fired, 220 t/h, steam generating boiler, including problems encountered, corrections made and resulting technical improvements achieved. This state-of-the-art process design technology is described to highlight newly demonstrated innovative features that include cost effective means for minimizing amount of purchase of hydrated lime, at the same time substantially decreasing reagent cost. Other key details included are system effectiveness in achieving very high lime-utilization (free lime concentration in the residue below 1 %); means for by-product (residue) utilization; very high operational availability since initial startup in May 1993; SO{sub 2} removal efficiency up to 97 %; and optimization of process economics through efforts for simplification of system operation and maintenance; and attractiveness in cost-effectively meeting diverse environmental pollution control objectives in varied, worldwide, FGD applications.

  13. High-temperature air/steam-blown gasification of coal in a pressurized spout-fluid bed

    SciTech Connect

    Rui Xiao; Mingyao Zhang; Baosheng Jin; Yaji Huang; Hongcang Zhou

    2006-03-15

    The concept of high-temperature air/steam-blown gasification technology for converting coal into low-caloric-value gas for power generation is proposed and evaluated experimentally. Preliminary experiments are performed in a 0.1 MW thermal input pressurized spout-fluid bed gasifier. The influences of the gasifying agent preheat temperature, the gasification temperature and pressure, the equivalence ratio, the ratio of steam-to-coal on gas composition, gas higher heating value, carbon conversion, and cold gas efficiency are examined. The experimental results prove the feasibility of high-temperature air/steam-blown gasification process. The gas heating value is increased by 23%, when the gasifying agent temperature is increased from 300 to 700 C. For the operation conditions studied, the results show that gasification temperature is the most important factor influencing coal gasification in the spout-fluid bed. The gasifier performance is improved at elevated pressure mainly due to the better fluidization in the reactor. The operating parameters of the equivalence ratio and the ratio of steam-to-coal exist at optimum operating range for a certain coal gasification process. 21 refs., 10 figs., 4 tabs.

  14. Computational fluid dynamics modelling of biomass fast pyrolysis in fluidised bed reactors, focusing different kinetic schemes.

    PubMed

    Ranganathan, Panneerselvam; Gu, Sai

    2016-08-01

    The present work concerns with CFD modelling of biomass fast pyrolysis in a fluidised bed reactor. Initially, a study was conducted to understand the hydrodynamics of the fluidised bed reactor by investigating the particle density and size, and gas velocity effect. With the basic understanding of hydrodynamics, the study was further extended to investigate the different kinetic schemes for biomass fast pyrolysis process. The Eulerian-Eulerian approach was used to model the complex multiphase flows in the reactor. The yield of the products from the simulation was compared with the experimental data. A good comparison was obtained between the literature results and CFD simulation. It is also found that CFD prediction with the advanced kinetic scheme is better when compared to other schemes. With the confidence obtained from the CFD models, a parametric study was carried out to study the effect of biomass particle type and size and temperature on the yield of the products. PMID:26927234

  15. Spatiotemporal Structure and Covariance of Bedload Motion and Near-Bed Fluid Velocity over Bedforms: Laboratory and Numerical Experiments Downstream of a Backward-Facing Step

    NASA Astrophysics Data System (ADS)

    Leary, K. P.; Schmeeckle, M. W.

    2014-12-01

    Despite numerous experimental and numerical studies investigating transport over ripples and dunes in rivers, the spatiotemporal details of the pattern of transport over bedforms remain largely unknown. Here we report turbulence-resolving, simultaneous measurements of bedload motion and near-bed fluid velocity downstream of a backward facing step in a laboratory flume. Details are compared to a coupled large eddy simulation and distinct element simulation (LES-DEM) of the same geometry. Two synchronized high-speed video cameras simultaneously observed bed load motion and the motion of neutrally buoyant particles in a laser light sheet 6 mm above the bed at 250 frames/s downstream of a 3.8 cm backward-facing step. Particle imaging velocimetry algorithms were applied to the laser sheet images to obtain two-dimensional field of two-dimensional vectors while manual particle tracking techniques were applied to the video images of the bed. As expected, there is a strong positive correlation between sediment flux and near-bed fluid velocity. Sediment flux was determined by manually tracking grains that passed over a 6 cm long line in the middle of the field of view on the bedload images. Sediment flux increased monotonically downstream of flow reattachment. Localized, intermittent, high-magnitude transport events were more apparent near flow reattachment than further downstream. Often, these high-magnitude events were seen to have significant cross-stream particle velocities. These events are consistent with permeable "splat events" visualized in the LES-DEM numerical simulations, wherein a volume of fluid moves toward and impinges on the bed. Fluid impingement and penetration of the bed results in outward flow and sediment motion from the center of the splat. Work is ongoing to quantify spatial and temporal autocorrelations and covariances of the fluid velocity and sediment motions.

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

    SciTech Connect

    Serrato, M. G.

    2013-09-27

    The DOE Office of Environmental management (DOE EM) faces the challenge of decommissioning thousands of excess nuclear facilities, many of which are highly contaminated. A number of these excess facilities are massive and robust concrete structures that are suitable for isolating the contained contamination for hundreds of years, and a permanent decommissioning end state option for these facilities is in situ decommissioning (ISD). The ISD option is feasible for a limited, but meaningfull number of DOE contaminated facilities for which there is substantial incremental environmental, safety, and cost benefits versus alternate actions to demolish and excavate the entire facility and transport the rubble to a radioactive waste landfill. A general description of an ISD project encompasses an entombed facility; in some cases limited to the blow-grade portion of a facility. However, monitoring of the ISD structures is needed to demonstrate that the building retains its structural integrity and the contaminants remain entombed within the grout stabilization matrix. The DOE EM Office of Deactivation and Decommissioning and Facility Engineering (EM-13) Program Goal is to develop a monitoring system to demonstrate long-term performance of closed nuclear facilities using the ISD approach. The Savannah River National Laboratory (SRNL) has designed and implemented the In Situ Decommissioning Sensor Network, Meso-Scale Test Bed (ISDSN-MSTB) to address the feasibility of deploying a long-term monitoring system into an ISD closed nuclear facility. The ISDSN-MSTB goal is to demonstrate the feasibility of installing and operating a remote sensor network to assess cementitious material durability, moisture-fluid flow through the cementitious material, and resulting transport potential for contaminate mobility in a decommissioned closed nuclear facility. The original ISDSN-MSTB installation and remote sensor network operation was demonstrated in FY 2011-12 at the ISDSN-MSTB test cube

  17. Feasibility studies in spheronization and scale-up of ibuprofen microparticulates using the rotor disk fluid-bed technology.

    PubMed

    Chukwumezie, Beatrice Nkem; Wojcik, Mark; Malak, Paul; Adeyeye, Moji Christianah

    2002-01-01

    The aim of this study was to develop spheronized microparticulates as a drug delivery system using the 1-step closed rotor disk fluid-bed technology, and to scale up the batch spheronization process. Ibuprofen was used as the model drug and microcrystalline cellulose/sodium carboxymethyl cellulose hydrocolloid (Avicel(R) RC-581 or CL-611) was present as the diluent/binder. The mixture, in 1:1 ratio, was blended with and without 1% sodium lauryl sulfate (SLS) and spheronized with the rotor disk insert, using either water or hydroxypropylmethyl cellulose (HPMC) as binder. Fluid-bed machines (Vector/Freund Flo-Coater model) FLM-1 (with 9-inch rotor insert for 0.75 kg) and FLM-15 (with a 12-inch and 19-inch rotor inserts for 1 kg and 5, 10 kg, respectively) were used. The critical process parameters included inlet air temperature, rotor disk speed and configuration, air flow, and rate of binder application. The 1 kg batch containing SLS that was made with 12-inch smooth stainless steel or waffle teflon plates rotating at 500 rpm had desirable characteristics. The sphericity values were 0.88 and 0.91, with percent yield of 85.4 and 91.2 and drug content values of 94.47% and 91.44%, respectively. The spheroids showed good flow properties with respective rapid drug release (Q20 = 83.27 and 91.75). No difference was seen in the Avicel RC-581 and CL-611. Based on the 1 kg data, Avicel RC-581 and smooth stainless steel and waffle teflon plates (12 inch and 19 inch), the batch was scaled up to 5 and 10 kg. The scale-up parameters included rotor speed (124 -300 rpm) and spray rate (90-140 g/min). The scale-up batches had similar flow characteristics, release rate, and size distribution. The geometric mean diameter increased as batch size increased, and slightly bigger spheroids were obtained using the waffle teflon plate. Ibuprofen spheres with very good physical characteristics were developed using the rotor disk fluid-bed technology, a 1-step closed process that did not

  18. Operation and maintenance experience of the Shamokin and Wilkes-Barre fluid bed boilers

    SciTech Connect

    Bersani, A.A.; Laukaitis, J.F.

    1986-01-01

    During the past 150 years, the anthracite coal industry of Northeastern Pennsylvania has deposited, above ground, approximately 1 billion tons of refuse, disfiguring the landscape and generally polluting the environment. Anthracite refuse is made up of breaker refuse or culm, silt, mine refuse and tunnel rock. Culm, containing appreciable amounts of carbon, is essentially a low quality, low cost, alternate energy source. This fuel with its high ash content, low heating value and generally high moisture content is considered to be a feasible fuel for a fluidized bed boiler.

  19. Fluid and electrolyte shifts in women during +Gz acceleration after 15 days' bed rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Stinnett, H. O.; Davis, G. L.; Kollias, J.; Bernauer, E. M.

    1977-01-01

    Experiments were conducted on twelve women aged 23-34 yr - a bed rest (BR) group of eight subjects and an ambulatory (AMB) group of four subjects - to determine the effect of bed rest on shifts in plasma volume, electrolytes, and erythrocyte volume during +Gz acceleration on a centrifuge. The BR group underwent the +Gz acceleration during a two-week ambulatory control period, after 15 days of a 17-day BR period, and on the third day of ambulatory recovery. The AMB group underwent the same experimental procedures, but continued their normal daily routine during the BR period without additional prescribed physical exercise. Major conclusions are that (1) the higher the mean control tolerance, the greater the tolerance decline after BR; (2) relative confinement and reduced activity contribute as much to reduction in tolerance as does the horizontal body position during BR; (3) BR deconditioning has no effect on the erythrocyte volume during +3.0 Gz; and (4) about one-half the loss in tolerance after BR can be attributed to plasma volume and electrolyte shifts.

  20. Combine waste-to-energy, recycling with fluid-bed boiler

    SciTech Connect

    Murphy, M.L.

    1995-04-01

    This article describes a plant that will be the first to incorporate a fluidized-bed boiler to burn refuse-derived fuel exclusively. An effective long-term solid-waste management program will soon be a reality for Bladen, Cumberland, and Hoke counties, North Carolina. The key element of the program is a 600-ton/day waste-to-energy (WTE) facility, scheduled to begin commercial operation later this year. The BCH Energy project, which gets its name from the initials of the three counties it serves, will become the first fluidized-bed boiler in the US designed to be fueled solely by refuse-derived fuel (RDF). As such, it provides an innovative and efficient approach to solid-waste management in several ways: (1) Maximizes community participation in a recovery and recycling effort. (2) Maximizes additional waste handling and hauling efforts. (3) Significantly reducing waste flow into landfill. (4) Eliminating use of fossil fuel for a nearby chemical plant`s energy load. (5) Substantially improves air quality through use of the latest combustion and emissions control technology.

  1. Alumina calcination with the advanced circulating fluid bed technology: A design with increased efficiency combined with operating flexibility

    SciTech Connect

    Schmidt, H.W.; Stockhausen, W.; Silberberg, A.N.

    1996-10-01

    The Circulating Fluid Bed (CFB) technology has now been applied to alumina calcination for a quarter of a century. The combined capacity of the 32 units installed is greater than 10 million metric tons per year. The paper highlights the consistency of the product quality which is based upon the operating experience of the last decade and improvements to the calcination system which also provides lower heat consumption. The principal modifications are incorporated in the preheating and cooling sections of the plant. These design modifications have also reduced capital cost. Overall the plant retains its proven features of high flexibility, unique temperature control, high availability, reliable performance, and low maintenance cost. The design is applicable to single train units up to a capacity of 3,000 MTPD (alumina).

  2. Determination of kinetic law for toxic metals release during thermal treatment of model waste in a fluid-bed reactor.

    PubMed

    Liu, Jing; Abanades, S; Gauthier, D; Flamant, G; Zheng, Chuguang; Lu, Jidong

    2005-12-01

    Accumulation of toxic metals generated by thermal treatment of municipal solid waste presents a serious threat to the environment. A study was carried out to investigate the kinetic law of toxic metal release from municipal solid waste during their thermal treatment. Both direct and inverse models were developed in transient conditions. The direct mathematical model of the fluid-bed reactor is based on Kunii and Levenspiel's two-phase flow model for Geldart Group B particles. The inverse model intends to predict the metal's rate of vaporization from its concentration in the outlet gas. The derived models were found to predict reasonably well the experimental observations. A method to derive the kinetic law of toxic metals release during fluidized bed thermal treatment of model waste from the global model and the experimental measurements is derived and illustrated. A first-order law was fitted for the mineral matrix, and a second-order law (simplified) was fitted for the realistic model waste. The kinetic law obtained in this way could be integrated in a global model of combustion of municipal solid waste in order to simulate the effects of operating parameters on the metal's behavior. PMID:16382960

  3. Integrated low emissions cleanup system for direct coal fueled turbines: (moving bed, fluid bed contactor/ceramic filter). Thirtieth quarterly report for the period January--March 1995

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1995-10-01

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of advanced, coal-fueled turbine power plants such as pressurized fluid bed combustion and coal gasification combined cycles. A major technical challenge remaining for the development of the coal-fueled turbine is high-temperature gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge. These UEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure process gases. This document reports the status of a program in the thirtieth quarter to develop this ILEC technology. During this Quarter of the program, the Phase In bench-scale, high-temperature, high-pressure (HTHP) testing of PFBC fly ashes was continued. Tests have been completed to characterize the filter cake pulse cleaning, as a function of temperature. The behavior trends are consistent with field unit observations. Sulfur removal tests, looking at the influence of SO{sub 2} on filter cake permeability, as well as the ability to remove sulfur by injecting dolomite into the filter, have been completed. Alkali removal tests were initiated this quarter injecting emathlite into the filter. A complete summary of the test procedures; tests completed and test results is presented in Appendices A, B and C. Preparation has been made to prepare the Phase III final report.

  4. Combine waste-to-energy, recycling with fluid-bed boiler

    SciTech Connect

    Murphy, M.L.

    1995-09-01

    An effective long-term solid-waste management program will soon be a reality for Bladen, Cumberland, and Hoke counties, North Carolina. The key element of the program is a 600-ton/day waste-to-energy (WTE) facility, scheduled to begin commercial operation later this year. The BCH Energy project, which gets its name from the initials of the three counties it serves, will become the first fluidized-bed boiler in the US designed to be fueled solely by refuse-derived fuel (RDF). As such, it provides an innovative and efficient approach to solid-waste management in several ways: (1) maximimizes community participation in a recovery and recycling effort; (2) maximizes additional waste handling and hauling efforts; (3) significantly reducing waste flow into landfill; (4) eliminating use of fossil fuel for a nearby chemical plant`s energy load; and (5) substantially improves air quality through use of the latest combustoin and emissions control technology.

  5. Analysis and control of the METC fluid-bed gasifier. Quarterly report, October 1994--January 1995

    SciTech Connect

    Farell, A.E.; Reddy, S.

    1995-03-01

    This document summarizes work performed for the period 10/1/94 to 2/1/95. The initial phase of the work focuses on developing a simple transfer function model of the Fluidized Bed Gasifier (FBG). This transfer function model will be developed based purely on the gasifier responses to step changes in gasifier inputs (including reactor air, convey air, cone nitrogen, FBG pressure, and coal feedrate). This transfer function model will represent a linear, dynamic model that is valid near the operating point at which the data was taken. In addition, a similar transfer function model will be developed using MGAS in order to assess MGAS for use as a model of the FBG for control systems analysis.

  6. Granular spirals on erodible sand bed submitted to a circular fluid motion.

    PubMed

    Caps, H; Vandewalle, N

    2003-09-01

    An experimental study of a granular surface submitted to a circular fluid motion is presented. The appearance of an instability along the sand-water interface is observed beyond a critical radius r(c). This creates ripples with a spiral shape on the granular surface. A phase diagram of such patterns is constructed and discussed as a function of the rotation speed omega of the flow and as a function of the height of water h above the surface. The study of r(c) as a function of h, omega, and r parameters is reported. Thereafter, r(c) is shown to depend on the rotation speed according to a power law. The ripple wavelength is found to decrease when the rotation speed increases and is proportional to the radial distance r. The azimuthal angle epsilon of the spiral arms is studied. It is found that epsilon scales with homegar. This lead to the conclusion that epsilon depends on the fluid momentum. Comparison with experiments performed with fluids allows us to state that the spiral patterns are not the signature of an instability of the boundary layer. PMID:14524759

  7. Laboratory-Scale Dam-Break Study of Gravity Currents with Basal Entrainment: PIV Measurements of a Viscous Newtonian Fluid over a Horizontal Bed of the same fluid showing Erosion and Deposition

    NASA Astrophysics Data System (ADS)

    Bates, B.; Ancey, C.; Busson, J.

    2012-12-01

    Geophysical gravity flows such as avalanches and debris flows belong to a special class of hazardous environmental event, in which a mixture of solids and fluids (e.g. debris and mud, snow and air) flow as a liquid and may run out much further than expected over a slope less steep than the critical angle of repose. Exchange of material between the overriding flow and a loose bed layer underneath is known to affect the characteristics of such a flow however it is not well understood how this plays a part, nor the mechanism of such an exchange, due to the difficulties of seeing inside a flowing mass in the field and experiments. Research has been carried out on an entraining viscous gravity current in an laboratory flume using Particle Image Velocimetry. The aim was to investigate the flow properties in a vertical slice of fluid in the downstream direction, far from the side-walls, when a flowing layer overrides a basal layer of the same material. The parameter varied here is the volume of fluid released from the reservoir, which affects the height and velocity of the encroaching fluid current. An interface was identified between the overriding fluid and the initially stationary bed fluid. PIV was used to show the evolution of the velocity and shear fields throughout the system compared to the location of this interface and how this changes with the volume of fluid released. The overriding fluid displaces the bed fluid, either by plunging or spilling into the erodible layer depending on the initial volume, thus inciting the stationary material downstream and below to move. Initially, a large amount of bed material is suddenly mobilized by the front of overriding fluid and little deposition occurs. Shortly after this we see the clear development of a depositional region (with low velocities, predominantly in the downwards direction) and an eroding region (with high, almost uniformly horizontal velocities) within the front of material that enters the bed, separated by

  8. Genome-Centric Analysis of Microbial Populations Enriched by Hydraulic Fracture Fluid Additives in a Coal Bed Methane Production Well.

    PubMed

    Robbins, Steven J; Evans, Paul N; Parks, Donovan H; Golding, Suzanne D; Tyson, Gene W

    2016-01-01

    Coal bed methane (CBM) is generated primarily through the microbial degradation of coal. Despite a limited understanding of the microorganisms responsible for this process, there is significant interest in developing methods to stimulate additional methane production from CBM wells. Physical techniques including hydraulic fracture stimulation are commonly applied to CBM wells, however the effects of specific additives contained in hydraulic fracture fluids on native CBM microbial communities are poorly understood. Here, metagenomic sequencing was applied to the formation waters of a hydraulically fractured and several non-fractured CBM production wells to determine the effect of this stimulation technique on the in-situ microbial community. The hydraulically fractured well was dominated by two microbial populations belonging to the class Phycisphaerae (within phylum Planctomycetes) and candidate phylum Aminicenantes. Populations from these phyla were absent or present at extremely low abundance in non-fractured CBM wells. Detailed metabolic reconstruction of near-complete genomes from these populations showed that their high relative abundance in the hydraulically fractured CBM well could be explained by the introduction of additional carbon sources, electron acceptors, and biocides contained in the hydraulic fracture fluid. PMID:27375557

  9. Genome-Centric Analysis of Microbial Populations Enriched by Hydraulic Fracture Fluid Additives in a Coal Bed Methane Production Well

    PubMed Central

    Robbins, Steven J.; Evans, Paul N.; Parks, Donovan H.; Golding, Suzanne D.; Tyson, Gene W.

    2016-01-01

    Coal bed methane (CBM) is generated primarily through the microbial degradation of coal. Despite a limited understanding of the microorganisms responsible for this process, there is significant interest in developing methods to stimulate additional methane production from CBM wells. Physical techniques including hydraulic fracture stimulation are commonly applied to CBM wells, however the effects of specific additives contained in hydraulic fracture fluids on native CBM microbial communities are poorly understood. Here, metagenomic sequencing was applied to the formation waters of a hydraulically fractured and several non-fractured CBM production wells to determine the effect of this stimulation technique on the in-situ microbial community. The hydraulically fractured well was dominated by two microbial populations belonging to the class Phycisphaerae (within phylum Planctomycetes) and candidate phylum Aminicenantes. Populations from these phyla were absent or present at extremely low abundance in non-fractured CBM wells. Detailed metabolic reconstruction of near-complete genomes from these populations showed that their high relative abundance in the hydraulically fractured CBM well could be explained by the introduction of additional carbon sources, electron acceptors, and biocides contained in the hydraulic fracture fluid. PMID:27375557

  10. Two stage fluid bed-plasma gasification process for solid waste valorisation: Technical review and preliminary thermodynamic modelling of sulphur emissions

    SciTech Connect

    Morrin, Shane; Lettieri, Paola; Chapman, Chris; Mazzei, Luca

    2012-04-15

    Highlights: Black-Right-Pointing-Pointer We investigate sulphur during MSW gasification within a fluid bed-plasma process. Black-Right-Pointing-Pointer We review the literature on the feed, sulphur and process principles therein. Black-Right-Pointing-Pointer The need for research in this area was identified. Black-Right-Pointing-Pointer We perform thermodynamic modelling of the fluid bed stage. Black-Right-Pointing-Pointer Initial findings indicate the prominence of solid phase sulphur. - Abstract: Gasification of solid waste for energy has significant potential given an abundant feed supply and strong policy drivers. Nonetheless, significant ambiguities in the knowledge base are apparent. Consequently this study investigates sulphur mechanisms within a novel two stage fluid bed-plasma gasification process. This paper includes a detailed review of gasification and plasma fundamentals in relation to the specific process, along with insight on MSW based feedstock properties and sulphur pollutant therein. As a first step to understanding sulphur partitioning and speciation within the process, thermodynamic modelling of the fluid bed stage has been performed. Preliminary findings, supported by plant experience, indicate the prominence of solid phase sulphur species (as opposed to H{sub 2}S) - Na and K based species in particular. Work is underway to further investigate and validate this.

  11. High-performance effluent-free pickling plants with fluid bed hydrochloric acid regeneration

    SciTech Connect

    Rituper, R.

    1995-11-01

    There is perpetual need to increase the performance of production facilities in the steel industry. Cost and product quality advantages, increased productivity and environmental acceptable processing of steel are the most important considerations in today`s highly competitive market. The newly developed Keramchemie strip pickle line, the Vario process, consists of a high-velocity pickling cell comprising a shallow, horizontal channel section that results in a turbulent flow behavior in the pickling section. Optimization of the pickling process is achieved by automatic setting of the pickling parameters such as acid flow and pressure via process control. Spent pickle liquor is completely regenerated in a recovery system using the fluidized bed process. The pickle liquor recycled between the pickling tanks and regeneration unit, results in a nearly zero consumption apart from small evaporation losses. The rinse water is completely reused. This makes an effluent-free operation of the pickling plant possible. No environmental pollution is caused by the pickling process. Some effluent-free strip pickling plants are already in operation in Europe with HCl consumption of less than 0.2 kg/tonne of pickled material.

  12. Origin of fluid inclusion water in bedded salt deposits, Palo Duro Basin, Texas

    SciTech Connect

    Knauth, L.P.; Beeunas, M.A.

    1985-07-01

    Salt horizons in the Palo Duro Basin being considered for repository sites contain fluid inclusions which may represent connate water retained in the salt from the time of original salt deposition and/or external waters which have somehow penetrated the salt. The exact origin of this water is important to the question of whether or not internal portions of the salt deposit have been, and are likely to be, isolated from the hydrosphere for long periods of time. The /sup 18/O//sup 16/O and D/H ratios measured for water extracted from solid salt samples show the inclusions to be dissimilar in isotopic composition to meteoric waters and to formation waters above and below the salt. The fluid inclusions cannot be purely external waters which have migrated into the salt. The isotope data are readily explained in terms of mixed meteoric-marine connate evaporite waters which date back to the time of deposition and early diagenesis of the salt (>250 million years). Any later penetration of the salt by meteoric waters has been insufficient to flush out the connate brines.

  13. Stable isotope composition of fluid inclusions preserved in halite derived from Wieliczka and Bochnia Salt Beds (Southern Poland)

    NASA Astrophysics Data System (ADS)

    Dulinski, Marek; Rozanski, Kazimierz; Bukowski, Krzysztof

    2010-05-01

    Halite deposits located in the southern Poland, near Krakow, are famous mostly due to the medieval salt mine located in Wieliczka. Contrary to most salt deposits in Europe forming large domes, the halite deposits near Krakow form distinct beds, extending from west to east on the area of ca. 10 km2, with several types of salt identified. The deposits were formed in shallow environment, ca. 15 mln years ago and represent initial stages of Miocene sea water evaporation. Stable isotope composition of fluid inclusions trapped in the halite crystals originating from Wieliczka and Bochnia salt mines was investigated. Three distinct groups of samples were analysed: (i) samples derived from so-called 'green salt' beds forming extensive horizontal structures, (ii) samples derived from so-called zuber-type salt, and (iii) large monocrystals of halite collected in two crystal caves existing in the mine. The samples belonging to the first and second group were heated under vacuum to extract the fluid inclusions, according to the procedure used previously to extract inclusions from speleothem samples. The macro-inclusions present in some monocrystals of halite collected in crystal caves were removed for analysis without any thermal treatment. The concentration of bivalent cations (Ca2+, Mg2+) was measured in the bulk material (green salt). K+, Mg2+ and SO4-2 content was measured in the fluid inclusions derived from macro-crystals. The stable isotope data points form two clusters in the δ2H-δ18O space, representing crystal caves and green- and zuber-type salts, respectively. The cluster representing green- and zuber-type salt deposit is shifted to the right-hand side of the Local Meteoric Water Line (LMWL), towards more positive δ2H and δ18O values, pointing to evaporative conditions during formation of these deposits. Although the evaporation trajectories for the sea water in the δ2H - δ18O space suggest that fluid inclusions might represent remnants of the original

  14. Fluidized bed combustion

    SciTech Connect

    Sowards, N.K.; Murphy, M.L.

    1992-04-07

    This patent describes a method of incinerating a fuel containing difficult to remove tramp comprising wire. It comprises placing of a fluid bed within a downwardly and inwardly tapered centrally hollow air distributor disposed within a lower portion of a vessel; introducing fuel comprising combustible material and tramp comprising wire into the fluid bed; incinerating the combustible material in the fluid bed accommodating downward migration within the fluid bed of the wire without a central obstruction to such migration; in the course of performing the incinerating step, fluidizing the bed solely by introducing inwardly at several tiered locations directed air into the bed only around the tapered periphery along the lower portion of the vessel from a plurality of inwardly and downwardly parallel sites as causing the bed material and tramp to migrate downwardly and inwardly without central bed obstruction toward a discharge site.

  15. Activated sludge process performance using a multistage tower aeration tank

    SciTech Connect

    Shimizu, Tatsuo; Kudo, Kenzo; Nasu, Yoshikazu )

    1993-07-01

    This study's objective was to clarify both experimentally and theoretically whether a vertical multistage tower aeration tank system is advantageous as compared with a completely mixed system, particularly with respect to purification efficiency, sludge settleability, and excess sludge production. In comparing the two systems: (1) purification efficiency in the multistage tower aeration system with partial fluid mixing with a large Peclet number was higher than in a corresponding completely mixed system for all applied organic loadings; (2) the multistage tower aeration system had some definite advantages with respect to sludge settleability and excess sludge production; and (3) the activated sludge system's higher performance with partial fluid mixing was shown quantitatively with the axial dispersion model in conjunction with growth kinetics which involved rapid uptake such as biosorption and subsequent oxidative biodegradation processes of organic substances.

  16. Multistage vector (MSV) therapeutics.

    PubMed

    Wolfram, Joy; Shen, Haifa; Ferrari, Mauro

    2015-12-10

    One of the greatest challenges in the field of medicine is obtaining controlled distribution of systemically administered therapeutic agents within the body. Indeed, biological barriers such as physical compartmentalization, pressure gradients, and excretion pathways adversely affect localized delivery of drugs to pathological tissue. The diverse nature of these barriers requires the use of multifunctional drug delivery vehicles that can overcome a wide range of sequential obstacles. In this review, we explore the role of multifunctionality in nanomedicine by primarily focusing on multistage vectors (MSVs). The MSV is an example of a promising therapeutic platform that incorporates several components, including a microparticle, nanoparticles, and small molecules. In particular, these components are activated in a sequential manner in order to successively address transport barriers. PMID:26264836

  17. Slope effects on the fluid dynamics of a fire spreading across a fuel bed: PIV measurements and OH* chemiluminescence imaging

    NASA Astrophysics Data System (ADS)

    Morandini, F.; Silvani, X.; Honoré, D.; Boutin, G.; Susset, A.; Vernet, R.

    2014-08-01

    Slope is among the most influencing factor affecting the spread of wildfires. A contribution to the understanding of the fluid dynamics of a fire spreading in these terrain conditions is provided in the present paper. Coupled optical diagnostics are used to study the slope effects on the flow induced by a fire at laboratory scale. Optical diagnostics consist of particle image velocimetry, for investigating the 2D (vertical) velocity field of the reacting flow and chemiluminescence imaging, for visualizing the region of spontaneous emission of OH radical occurring during gaseous combustion processes. The coupling of these two techniques allows locating accurately the contour of the reaction zone within the computed velocity field. The series of experiments are performed across a bed of vegetative fuel, under both no-slope and 30° upslope conditions. The increase in the rate of fire spread with increasing slope is attributed to a significant change in fluid dynamics surrounding the flame. For horizontal fire spread, flame fronts exhibit quasi-vertical plume resulting in the buoyancy forces generated by the fire. These buoyancy effects induce an influx of ambient fresh air which is entrained laterally into the fire, equitably from both sides. For upward flame spread, the induced flow is strongly influenced by air entrainment on the burnt side of the fire and fire plume is tilted toward unburned vegetation. A particular attention is paid to the induced air flow ahead of the spreading flame. With increasing the slope angle beyond a threshold, highly dangerous conditions arise because this configuration induces wind blows away from the fire rather than toward it, suggesting the presence of convective heat transfers ahead of the fire front.

  18. Hydrodynamics and energy consumption studies in a three-phase liquid circulating three-phase fluid bed contactor

    SciTech Connect

    Rusumdar, Ahmad J; Abuthalib, A.; Mohan, Vaka Murali; Srinivasa Kumar, C.; Sujatha, V.; Rajendra Prasad, P.

    2009-07-15

    The hydrodynamics and energy consumption have been studied in a cold flow, bubbling and turbulent, pressurized gas-liquid-solid three-phase fluidized bed (0.15 m ID x 1 m height) with concurrent gas-liquid up flow is proposed with the intention of increasing the gas hold up. The hydrodynamic behaviour is described and characterised by some specific gas and liquid velocities. Particles are easily fluidized and can be uniformly distributed over the whole height of the column. The effect of parameters like liquid flow rate, gas flow rate, particle loading, particle size, and solid density on gas hold up and effect of gas flow rate, solid density and particle size on solid hold up, energy consumption and minimum fluidization velocity has been studied. At the elevated pressures a superior method for better prediction of minimum fluidization velocity and terminal settling velocities has been adopted. The results have been interpreted with Bernoulli's theorem and Richardson-Zaki equation. Based on the assumption of the gas and liquid as a pretend fluid, a simplification has been made to predict the particle terminal settling velocities. The Richardson-Zaki parameter n' was compared with Renzo's results. A correlation has been proposed with the experimental results for the three-phase fluidization. (author)

  19. The Multistage Compressor Facility

    NASA Technical Reports Server (NTRS)

    Flegel, Ashlie

    2004-01-01

    Research and developments of new aerospace technologies is one of Glenn Research Center's specialties. One facility that deals with the research of aerospace technologies is the High-speed Multistage Compressor Facility. This facility will be testing the performance and efficiency of an Ultra Efficient Engine Technology (UEET) two-stage compressor. There is a lot of preparation involved with testing something of this caliber. Before the test article can be installed into the test rig, the facility must be fully operational and ready to run. Meaning all the necessary instrumentation must be calibrated and installed in the facility. The test rig should also be in safe operating condition, and the proper safety permits obtained. In preparation for the test, the Multistage Compressor Facility went through a few changes. For instance the facility will now be utilizing slip rings, the gearbox went through some maintenance, new lubrications systems replaced the old ones, and special instrumentation needs to be fine tuned to achieve the maximum amount of accurate data. Slips rings help gather information off of a rotating device - in this case from a shaft - onto stationary contacts. The contacts (or brushes) need to be cooled to reduce the amount of frictional heat produced between the slip ring and brushes. The coolant being run through the slip ring is AK-225, a material hazardous to the ozone. To abide by the safety regulations the coolant must be run through a closed chiller system. A new chiller system was purchased but the reservoir that holds the coolant was ventilated which doesn t make the system truly closed and sealed. My task was to design and have a new reservoir built for the chiller system that complies with the safety guidelines. The gearbox had some safety issues also. Located in the back of the gearbox an inching drive was set up. When the inching drive is in use the gears and chain are bare and someone can easily get caught up in it. So to prevent

  20. Physiological responses to prolonged bed rest and fluid immersion in man: A compendium of research (1974 - 1980)

    NASA Technical Reports Server (NTRS)

    Greenleaf, J. E.; Silverstein, L.; Bliss, J.; Langenheim, V.; Rosson, H.; Chao, C.

    1982-01-01

    Water immersion and prolonged bed rest reproduce nearly all the physiological responses observed in astronauts in the weightless state. Related to actual weightlessness, given responses tend to occur sooner in immersion and later in bed rest. Much research was conducted on humans using these two techniques, especially by Russian scientists. Abstracts and annotations of reports that appeared in the literature from January 1974 through December 1980 are compiled and discussed.

  1. Integrated Low Emissions Cleanup system for direct coal fueled turbines, (moving bed, fluid bed contactor/ceramic filter). Twenty-fourth quarterly status report, July--September 1993

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1993-12-31

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge: a baseline ceramic barrier filter ILEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300{degree}F. This document reports the status of a program in the nineteenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.

  2. Integrated low emissions cleanup system for direct coal fueled turbines (moving bed, fluid bed contactor/ceramic filter). Twentieth quarterly status report, July--September 1992

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1992-10-20

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meat this technical challenge: a baseline ceramic barrier filter ILEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300{degree}F. This document reports the status of a program in the nineteenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.

  3. Integrated low emissions cleanup system for direct coal fueled turbines (moving bed, fluid bed contactor/ceramic filter). Twenty-third quarterly status report, April--June 1993

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1993-07-19

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge: A baseline ceramic barrier filter ILEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300{degrees}F. This document reports the status of a program in the nineteenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.

  4. Integrated low emissions cleanup system for direct coal fueled turbines (Moving bed, fluid bed contactor/ceramic filter). Seventeenth quarterly status report, October--December 1991

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1992-01-20

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge: a baseline ceramic barrier filter ILEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300{degrees}F. This document reports the status of a program in the seventeenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.

  5. Analysis and control of the METC fluid bed gasifier. Final report (includes technical progress report for October 1994--January 1995), September 1994--September 1996

    SciTech Connect

    1996-09-01

    This document presents a modeling and control study of the Fluid Bed Gasification (FBG) unit at the Morgantown Energy Technology Center (METC). The work is performed under contract no. DE-FG21-94MC31384. The purpose of this study is to generate a simple FBG model from process data, and then use the model to suggest an improved control scheme which will improve operation of the gasifier. The work first developes a simple linear model of the gasifier, then suggests an improved gasifier pressure and MGCR control configuration, and finally suggests the use of a multivariable control strategy for the gasifier.

  6. Integrated low emissions cleanup system for direct coal fueled turbines (moving bed, fluid bed contactor/ceramic filter). Eighteenth quarterly status report, January--March 1992

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1992-04-20

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge: a baseline ceramic barrier filter nEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300{degrees}F. This document reports the status of a program in the eighteenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.

  7. Integrated Low Emissions Cleanup system for direct coal fueled turbines (moving bed, fluid bed contactor/ceramic filter). Twenty-fifth quarterly report, October--December 1993

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1993-12-31

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been reconfigured to meet this technical challenge: a baseline ceramic barrier filter ILEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300{degree}F. This document reports the status of a program in the twenty-fifth quarter to develop this ILEC technology for direct coal-fired turbine power plants.

  8. Fluid mixing during deposition of bedded-replacement (BR) deposits in the Illinois-Kentucky fluorspar district

    SciTech Connect

    Spry, P.G.; Fuhrmann, G.D. . Dept. of Geological Atmospheric Sciences)

    1993-03-01

    The Illinois-Kentucky(IK) district is unusual by comparison to other Mississippi Valley-type (MVT) districts in the central US in that it contains fluorspar mineralization primarily, with subordinate quantities of base metals. This mineralization occurs as vein, BR, and breccia-hosted deposits. A clearly discernible paragenetic sequence of color banded fluorite sulfides, carbonates, and sulfates is present in BR deposits in three sub-districts: Cave-in-Rock, Harris Creek, and Carrsville. Homogenization temperatures (T[sub b]) and salinities of fluids in fluorite show that BR deposits formed from at least three fluids, a lower temperature-higher salinity connate fluid (F1) and a higher temperature-lower salinity connate fluid (F2) that mixed at the site of deposition. These fluids were followed by a lower temperature-lower salinity meteoric dominated fluid (F3). The involvement of two distinct regional fluids: a lower temperature, more-saline fluid, and a warmer, less-saline fluid, during mineralization of MVT deposits has previously been recognized for Pb-Zn deposits in southeast Missouri (Shelton et al., 1992), and east Tennessee (Zimmerman and Kesler, 1981; Taylor et al. 1983).

  9. CHEMICALLY ACTIVE FLUID-BED PROCESS FOR SULPHUR REMOVAL DURING GASIFICATION OF HEAVY FUEL OIL - FOURTH PHASE

    EPA Science Inventory

    The report gives results of Phase 4 of a study on the CAFB process for gasification/desulfurization of liquid and solid fuels in a bed of hot lime. A new pilot unit was designed and constructed, incorporating such novel features as: a new fluidizing air distributor, high-flow/low...

  10. CHEMICALLY ACTIVE FLUID-BED PROCESS FOR SULPHUR REMOVAL DURING GASIFICATION OF HEAVY FUEL OIL - SECOND PHASE

    EPA Science Inventory

    The report describes the second phase of studies on the CAFB process for desulfurizing gasification of heavy fuel oil in a bed of hot lime. The first continuous pilot plant test with U.S. limestone BCR 1691 experienced local stone sintering and severe production of sticky dust du...

  11. CHEMICALLY ACTIVE FLUID-BED PROCESS FOR SULPHUR REMOVAL DURING GASIFICATION OF HEAVY FUEL OIL - THIRD PHASE

    EPA Science Inventory

    The report describes the third phase of studies on the CAFB process for desulfurization/gasification of heavy fuel oil in a bed of hot lime. Major conclusions relating to process performance and operability are: (1) water, either in the fuel or in the fluidizing air, has a strong...

  12. Enhanced dissolution, stability and physicochemical characterization of ATRA/2-hydroxypropyl-β-cyclodextrin inclusion complex pellets prepared by fluid-bed coating technique.

    PubMed

    Chen, Zhongjian; Lu, Yi; Qi, Jianping; Wu, Wei

    2013-02-01

    The aim of this work was to prepare stable all-trans-retinoic acid (ATRA)/2-hydroxypropyl-β-cyclodextrin (HPCD) inclusion complex pellets with industrial feasible technology, the fluid-bed coating technique, using PVP K30 simultaneously as binder and reprecipitation retarder. The coating process was fluent with high coating efficiency. In vitro dissolution of the inclusion complex pellets in 5% w/v Cremopher EL solution was dramatically enhanced with no reprecipitation observed, and significantly improved stability against humidity (92.5% and 75% RH) and illumination (4500 lx ± 500 lx) was achieved by HPCD inclusion. Differential scanning calorimetry and powder X-ray diffractometry confirmed the absence of crystallinity of ATRA. Fourier transform-infrared spectrometry revealed interaction between ATRA and HPCD adding evidence on inclusion of ATRA moieties into HPCD cavities. Solid-state (13)C NMR spectrometry indicated possible inclusion of ATRA through the polyene chain, which was the main reason for the enhanced photostability. It is concluded that the fluid-bed coating technique has the potential use in the industrial preparation of ATRA/HPCD inclusion complex pellets. PMID:22304703

  13. Understand multistage compressor antisurge control

    SciTech Connect

    Rana, S.A.Z.

    1985-03-01

    Methods for, and the principles of antisurge control for multistage centrifugal compressors will be discussed without going into the mathematical details of the theories. Application of these principles is illustrated with an example for a three-stage centrifugal compressor with side suction lines. These principles are not normally discussed in the literature, so this article should be useful to beginners in this field and also serve as a review for more experienced engineers.

  14. Fluidized bed combustion

    SciTech Connect

    Sowards, N.K.; Murphy, M.L.

    1991-10-29

    This patent describes a vessel. It comprises a fluid bed for continuously incinerating fuel comprising tire segments and the like which comprise metallic wire tramp and for concurrently removing tramp and bed materials at a bottom effluent exit means of the vessel, the vessel further comprising static air distributor means at the periphery of the bed comprising a substantially centrally unobstructed relatively large central region in which the fluid bed and fuel only are disposed and through which bed material and tramp migrate without obstruction to and through the effluent exit means, downwardly and inwardly stepped lower vessel wall means and a plurality of peripherally located centrally directed vertically and horizontally offset spaced air influent means surrounding the central region and associated with the stepped lower vessel wall means by which the bed is supported and fluidized.

  15. Development of advanced fluid-bed agglomeration and cyclonic incineration for simultaneous waste disposal and energy recovery

    SciTech Connect

    Rehmat, A.; Khinkis, M.

    1991-01-01

    The Institute of Gas Technology (IGT) is currently developing a two-stage fluidized-bed/cyclonic agglomerating incineration system for waste disposal that is based on combining the fluidized-bed agglomeration/incineration and cyclonic combustion techologies. Both technologies have been developed individually at IGT over many years. This combination has resulted in a unique and extremely flexible incinerator for solid, liquid, and gaseous wastes including municipal sludges. The system can operate over a wide range of conditions in the first stage, from low temperature (desorption) to high temperature (agglomeration), including gasification of wastes. In the combined system, solid, liquid, and gaseous organic wastes are incinerated with ease and great efficiency (>99.99% destruction and removal efficiency (DRE)), while solid inorganic contaminants contained within a glassy matrix are rendered benign and suitable for disposal in an ordinary landfill. The heat generated within the incinerator can be recovered using the state-of-the-art boilers. The development of the two-stage incinerator is a culmination of extensive research and development efforts on each stage of the incinerator. The variety of data obtained with solid, liquid, and gaseous wastes for both stages includes agglomeration of ash, incineration and reclamation of used blast grit and foundry sand, partial combustion of carbonaceous fuels, in-situ desulfurization, combustion of low-Btu gases, incineration of industrial wastewater, and incineration of carbon tetrachloride. 5 refs., 7 figs., 12 tabs.

  16. Queuing register uses fluid logic elements

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Queuing register /a multistage bit-shifting device/ uses a series of pure fluid elements to perform the required logic operations. The register has several stages of three-state pure fluid elements combined with two-input NOR gates.

  17. Application of computational fluid dynamics for the simulation of cryogenic molecular sieve bed absorber of hydrogen isotopes recovery system for Indian LLCB-TBM

    SciTech Connect

    Gayathri Devi, V.; Sircar, A.; Sarkar, B.

    2015-03-15

    One of the most challenging tasks in the design of the fuel cycle system lies in the effective design of Tritium Extraction System (TES) which involves proper extraction and purification of tritium in the fuel cycle of the fusion reactor. Indian Lead Lithium cooled Ceramic Breeder Test Blanket Module (LLCB-TBM) would extract hydrogen isotopes through Cryogenic Molecular Sieve Bed (CMSB) adsorber system. A prototype Hydrogen Isotopes Recovery System (HIRS) is being developed to validate the concepts for tritium extraction by adsorption mass transfer mechanism. In this study, a design model has been developed and analyzed to simulate the adsorption mass transfer kinetics in a fixed bed adsorption column. The simulation leads primarily to effective design of HIRS, which is a state-of-the-art technology. The paper describes the process simulation approach and the results of Computational Fluid Dynamics (CFD) analysis. The effects of different operating conditions are studied to investigate their influence on the hydrogen isotopes adsorption capacity. The results of the present simulation study would be used to understand the best optimized transport phenomenon before realizing the TES as a system for LLCB-TBM. (authors)

  18. Multilevel codes and multistage decoding

    NASA Astrophysics Data System (ADS)

    Calderbank, A. R.

    1989-03-01

    Imai and Hirakawa have proposed (1977) a multilevel coding method based on binary block codes that admits a staged decoding procedure. Here the coding method is extended to coset codes and it is shown how to calculate minimum squared distance and path multiplicity in terms of the norms and multiplicities of the different cosets. The multilevel structure allows the redundancy in the coset selection procedure to be allocated efficiently among the different levels. It also allows the use of suboptimal multistage decoding procedures that have performance/complexity advantages over maximum-likelihood decoding.

  19. Feet swelling in a multistage ultraendurance triathlete: a case study.

    PubMed

    Knechtle, Beat; Zingg, Matthias Alexander; Knechtle, Patrizia; Rosemann, Thomas; Rüst, Christoph Alexander

    2015-01-01

    Recent studies investigating ultraendurance athletes showed an association between excessive fluid intake and swelling of the lower limbs such as the feet. To date, this association has been investigated in single-stage ultraendurance races, but not in multistage ultraendurance races. In this case study, we investigated a potential association between fluid intake and feet swelling in a multistage ultraendurance race such as a Deca Iron ultratriathlon with ten Ironman triathlons within 10 consecutive days. A 49-year-old well-experienced ultratriathlete competed in autumn 2013 in the Deca Iron ultratriathlon held in Lonata del Garda, Italy, and finished the race as winner within 129:33 hours:minutes. Changes in body mass (including body fat and lean body mass), foot volume, total body water, and laboratory measurements were assessed. Food and fluid intake during rest and competing were recorded, and energy and fluid turnovers were estimated. During the ten stages, the volume of the feet increased, percentage body fat decreased, creatinine and urea levels increased, hematocrit and hemoglobin values decreased, and plasma [Na(+)] remained unchanged. The increase in foot volume was significantly and positively related to fluid intake during the stages. The poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. This case report shows that the volume of the foot increased during the ten stages, and the increase in volume was significantly and positively related to fluid intake during the stages. Furthermore, the poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. The continuous feet swelling during the race was most probably due to a combination of a high fluid intake and a progressive decline in renal function (ie, continuous increase in creatinine and urea), leading to body fluid retention (ie, increase in total body water). PMID:26508884

  20. Feet swelling in a multistage ultraendurance triathlete: a case study

    PubMed Central

    Knechtle, Beat; Zingg, Matthias Alexander; Knechtle, Patrizia; Rosemann, Thomas; Rüst, Christoph Alexander

    2015-01-01

    Recent studies investigating ultraendurance athletes showed an association between excessive fluid intake and swelling of the lower limbs such as the feet. To date, this association has been investigated in single-stage ultraendurance races, but not in multistage ultraendurance races. In this case study, we investigated a potential association between fluid intake and feet swelling in a multistage ultraendurance race such as a Deca Iron ultratriathlon with ten Ironman triathlons within 10 consecutive days. A 49-year-old well-experienced ultratriathlete competed in autumn 2013 in the Deca Iron ultratriathlon held in Lonata del Garda, Italy, and finished the race as winner within 129:33 hours:minutes. Changes in body mass (including body fat and lean body mass), foot volume, total body water, and laboratory measurements were assessed. Food and fluid intake during rest and competing were recorded, and energy and fluid turnovers were estimated. During the ten stages, the volume of the feet increased, percentage body fat decreased, creatinine and urea levels increased, hematocrit and hemoglobin values decreased, and plasma [Na+] remained unchanged. The increase in foot volume was significantly and positively related to fluid intake during the stages. The poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. This case report shows that the volume of the foot increased during the ten stages, and the increase in volume was significantly and positively related to fluid intake during the stages. Furthermore, the poststage volume of the foot was related to poststage total body water, poststage creatinine, and poststage urea. The continuous feet swelling during the race was most probably due to a combination of a high fluid intake and a progressive decline in renal function (ie, continuous increase in creatinine and urea), leading to body fluid retention (ie, increase in total body water). PMID:26508884

  1. An improved capillary model for describing the microstructure characteristics, fluid hydrodynamics and breakthrough performance of proteins in cryogel beds.

    PubMed

    Yun, Junxian; Jespersen, Gry Ravn; Kirsebom, Harald; Gustavsson, Per-Erik; Mattiasson, Bo; Galaev, Igor Yu

    2011-08-12

    A capillary-based model modified for characterization of monolithic cryogels is presented with key parameters like the pore size distribution, the tortuosity and the skeleton thickness employed for describing the porous structure characteristics of a cryogel matrix. Laminar flow, liquid dispersion and mass transfer in each capillary are considered and the model is solved numerically by the finite difference method. As examples, two poly(hydroxyethyl methacrylate) (pHEMA) based cryogel beds have been prepared by radical cryo-copolymerization of monomers and used to test the model. The axial dispersion behaviors, the pressure drop vs. flow rate performance as well as the non-adsorption breakthrough curves of different proteins, i.e., lysozyme, bovine serum albumin (BSA) and concanavalin A (Con A), at various flow velocities in the cryogel beds are measured experimentally. The lumped parameters in the model are determined by matching the model prediction with the experimental data. The results showed that for a given cryogel column, by using the model based on the physical properties of the cryogel (i.e., diameter, length, porosity, and permeability) together with the protein breakthrough curves one can obtain a reasonable estimate and detailed characterization of the porous structure properties of cryogel matrix, particularly regarding the number of capillaries, the capillary tortuousness, the pore size distribution and the skeleton thickness. The model is also effective with regards to predicting the flow performance and the non-adsorption breakthrough profiles of proteins at different flow velocities. It is thus expected to be applicable for characterizing the properties of cryogels and predicting the chromatographic performance under a given set of operating conditions. PMID:21742336

  2. Thermal energy storage systems using fluidized bed heat exchangers

    NASA Technical Reports Server (NTRS)

    Weast, T.; Shannon, L.

    1980-01-01

    A rotary cement kiln and an electric arc furnace were chosen for evaluation to determine the applicability of a fluid bed heat exchanger (FBHX) for thermal energy storage (TES). Multistage shallow bed FBHX's operating with high temperature differences were identified as the most suitable for TES applications. Analysis of the two selected conceptual systems included establishing a plant process flow configuration, an operational scenario, a preliminary FBHX/TES design, and parametric analysis. A computer model was developed to determine the effects of the number of stages, gas temperatures, gas flows, bed materials, charge and discharge time, and parasitic power required for operation. The maximum national energy conservation potential of the cement plant application with TES is 15.4 million barrels of oil or 3.9 million tons of coal per year. For the electric arc furnance application the maximum national conservation potential with TES is 4.5 million barrels of oil or 1.1 million tons of coal per year. Present time of day utility rates are near the breakeven point required for the TES system. Escalation of on-peak energy due to critical fuel shortages could make the FBHX/TES applications economically attractive in the future.

  3. Multi-stage complex contagions.

    PubMed

    Melnik, Sergey; Ward, Jonathan A; Gleeson, James P; Porter, Mason A

    2013-03-01

    The spread of ideas across a social network can be studied using complex contagion models, in which agents are activated by contact with multiple activated neighbors. The investigation of complex contagions can provide crucial insights into social influence and behavior-adoption cascades on networks. In this paper, we introduce a model of a multi-stage complex contagion on networks. Agents at different stages-which could, for example, represent differing levels of support for a social movement or differing levels of commitment to a certain product or idea-exert different amounts of influence on their neighbors. We demonstrate that the presence of even one additional stage introduces novel dynamical behavior, including interplay between multiple cascades, which cannot occur in single-stage contagion models. We find that cascades-and hence collective action-can be driven not only by high-stage influencers but also by low-stage influencers. PMID:23556961

  4. Multi-stage complex contagions

    NASA Astrophysics Data System (ADS)

    Melnik, Sergey; Ward, Jonathan A.; Gleeson, James P.; Porter, Mason A.

    2013-03-01

    The spread of ideas across a social network can be studied using complex contagion models, in which agents are activated by contact with multiple activated neighbors. The investigation of complex contagions can provide crucial insights into social influence and behavior-adoption cascades on networks. In this paper, we introduce a model of a multi-stage complex contagion on networks. Agents at different stages—which could, for example, represent differing levels of support for a social movement or differing levels of commitment to a certain product or idea—exert different amounts of influence on their neighbors. We demonstrate that the presence of even one additional stage introduces novel dynamical behavior, including interplay between multiple cascades, which cannot occur in single-stage contagion models. We find that cascades—and hence collective action—can be driven not only by high-stage influencers but also by low-stage influencers.

  5. Wadeite (K2ZrSi3O9), an alkali-zirconosilicate from the Saima agpaitic rocks in northeastern China: Its origin and response to multi-stage activities of alkaline fluids

    NASA Astrophysics Data System (ADS)

    Wu, Bin; Wang, Ru-Cheng; Yang, Jin-Hui; Wu, Fu-Yuan; Zhang, Wen-Lan; Gu, Xiang-Ping; Zhang, Ai-Cheng

    2015-05-01

    The Triassic Saima alkaline complex in the Liaodong Peninsula of northeastern China covers an area of about 20 km2 and is dominated by nepheline syenite, with phonolite at its center, and a concealed body of eudialyte-bearing nepheline syenite in the northwest of the complex. The phonolite has similar features to miaskite, while the nepheline syenites are classified in the agpaitic group according to their mineral assemblage, and the alkalinity and aluminum saturation indexes. Zircon is the dominant Zr-bearing mineral in the phonolite, whereas wadeite occurs as the only primary Zr-bearing mineral in the nepheline syenites. The transitional crystallization from zircon to wadeite reveals an increase in alkalis and a high K/Na ratio as the magmas evolved from the volcanic to the intrusive stage. The primary wadeite grains underwent varying degrees of hydrothermal alteration. Overall, the areas of weak, medium, and strong alteration are characterized by the following respective associations: (1) wadeite + secondary catapleiite/gaidonnayite, (2) wadeite + secondary catapleiite/gaidonnayite + zircon, and (3) pseudomorphs after wadeite. The pseudomorphs are widespread and mainly consist of residual wadeite, secondary zircon, catapleiite/gaidonnayite, K-feldspar, calcite, and some Zr-bearing titanite and vesuvianite. All of the secondary zircon grains in the three associations are typically enriched in Ca and Al compared with the primary Ca-free zircons of the phonolite. The progressive alteration of wadeite suggests that the Saima complex underwent multiple episodes of fluid activity during a hydrothermal stage, including an initial Na-metasomatism via alkaline fluids, then stages most likely involving progressively CO2-rich fluids, and an intensive episode involving a mixture of these fluids with externally derived Ca-rich fluids.

  6. Multi-stage desulfurizing fluid-bed combustor for coal-fired hot gas generator systems: Topical report No. 3. Task 6. Modifications to Materials Handling Equipment. Task 7. Testing

    SciTech Connect

    Lowell, C.

    1981-04-01

    This report covers the modification of Materials Handling Equipment, Testing and Program Management of Tasks 6, 7 and 8 of Phase 2. The Cohogg system contains a pyrolyzer for partial gasification of the coal through sub-stoichiometric combustion, a char burner which burns the char (generated in the pyrolyzer) in excess air, and an afterburner where the pyrolyzer gases and the char burner gases mix to produce a high temperature (approx. 3000/sup 0/F) environmentally clean flame capable of replacing an oil or gas burner. The system has operated successfully and demonstrated the capability of producing an environmentally clean high temperature flame. Operation with 15% excess air overall demonstrated a 3200/sup 0/F capability while sulfur retention was in excess of 90%. After more than 100 hours of operation the system shows itself to have flexibility in coal type, sorbent type, and operating temperatures while maintaining a clean high temperature flame and meeting or exceeding current pollution restrictions.

  7. Influence of binder properties, method of addition, powder type and operating conditions on fluid-bed melt granulation and resulting tablet properties.

    PubMed

    Abberger, T

    2001-12-01

    The aim of the study was to investigate melt granulation in a laboratory scale fluid-bed granulator with respect to granule growth, granule properties and resulting tablet properties. The parameters investigated were method of addition of PEG (spray-on or addition as flakes), binder concentration, PEG type (3000, 4000 and 6000, sprayed-on), size (PEG 4000, added as three different sized flakes), powder type (two different sized lactose types and corn starch) and operating conditions (volume air flow and heating temperature). Addition of binder as flakes led to layering as a growth mechanism when the size of the flakes was high. Coalescence occurred when the size was low. Coalescence also occurred when spraying was the method of addition. Due to the greater viscosity of the PEG 6000 melt it produced bigger granules than 3000 or 4000. The influence of volume air flow was moderate and the influence of heating temperature in the range of 70-90 degrees C was very low with both methods of addition. The disintegration time of tablets from granules where PEG was added as flakes was shorter than from granules where PEG was sprayed-on. The latter method of binder addition led to tablets which did not disintegrate but eroded. This was apparently caused by formation of a binder matrix, which could not be destroyed by the disintegrant. PMID:11802658

  8. Effectiveness of an anaerobic granular activated carbon fluidized-bed bioreactor to treat soil wash fluids: a proposed strategy for remediating PCP/PAH contaminated soils.

    PubMed

    Koran, K M; Suidan, M T; Khodadoust, A P; Sorial, G A; Brenner, R C

    2001-07-01

    An integrated system has been developed to remediate soils contaminated with pentachlorophenol (PCP) and polycyclic aromatic hydrocarbons (PAHs). This system involves the coupling of two treatment technologies, soil-solvent washing and anaerobic biotreatment of the extract. Specifically, this study evaluated the effectiveness of a granular activated carbon (GAC) fluidized-bed reactor to treat a synthetic-waste stream of PCP and four PAHs (naphthalene, acenaphthene, pyrene, and benzo(b)fluoranthene) under anaerobic conditions. This waste stream was intended to simulate the wash fluids from a soil washing process treating soils from a wood-preserving site. The reactor achieved a removal efficiency of greater than 99.8% for PCP with conversion to its dechlorination intermediates averaging 46.5%. Effluent, carbon extraction, and isotherm data also indicate that naphthalene and acenaphthene were removed from the liquid phase with efficiencies of 86 and 93%, respectively. Effluent levels of pyrene and benzo(b)fluoranthene were extremely low due to the high-adsorptive capacity of GAC for these compounds. Experimental evidence does not suggest that the latter two compounds were biochemically transformed within the reactor. PMID:11394769

  9. Multistage Simulations of the GE90 Turbine

    NASA Technical Reports Server (NTRS)

    Turner, Mark G.; Vitt, Paul H.; Topp, David A.; Saeidi, Sohrab; Hunter, Scott D.; Dailey, Lyle D.; Beach, Timothy A.

    1999-01-01

    The average passage approach has been used to analyze three multistage configurations of the GE90 turbine. These are a high pressure turbine rig, a low pressure turbine rig and a full turbine configuration comprising 18 blade rows of the GE90 engine at takeoff conditions. Cooling flows in the high pressure turbine have been simulated using source terms. This is the first time a dual-spool cooled turbine has been analyzed in 3D using a multistage approach. There is good agreement between the simulations and experimental results. Multistage and component interaction effects are also presented. The parallel efficiency of the code is excellent at 87.3% using 121 processors on an SGI Origin for the 18 blade row configuration. The accuracy and efficiency of the calculation now allow it to be effectively used in a design environment so that multistage effects can be accounted for in turbine design.

  10. EMERGING TECHNOLOGY BULLETIN: SPOUTED BED REACTOR

    EPA Science Inventory

    The Spouted Bed Reactor (SBR) technology utilizes the unique attributes of the "spouting " fluidization regime, which can provide heat transfer rates comparable to traditional fluid beds, while providing robust circulation of highly heterogeneous solids, concurrent with very agg...

  11. Fast fluidized bed steam generator

    DOEpatents

    Bryers, Richard W.; Taylor, Thomas E.

    1980-01-01

    A steam generator in which a high-velocity, combustion-supporting gas is passed through a bed of particulate material to provide a fluidized bed having a dense-phase portion and an entrained-phase portion for the combustion of fuel material. A first set of heat transfer elements connected to a steam drum is vertically disposed above the dense-phase fluidized bed to form a first flow circuit for heat transfer fluid which is heated primarily by the entrained-phase fluidized bed. A second set of heat transfer elements connected to the steam drum and forming the wall structure of the furnace provides a second flow circuit for the heat transfer fluid, the lower portion of which is heated by the dense-phase fluidized bed and the upper portion by the entrained-phase fluidized bed.

  12. Technology test bed review

    NASA Astrophysics Data System (ADS)

    McConnaughey, H. V.

    1992-07-01

    The topics are presented in viewgraph form and include the following: (1) Space Shuttle Main Engine (SSME) technology test bed (TTB) history; (2) TTB objectives; (3) TTB major accomplishments; (4) TTB contributions to SSME; (5) major impacts of 3001 testing; (6) some challenges to computational fluid dynamics (CFD); (7) the high pressure fuel turbopump (HPFTP); and (8) 3001 lessons learned in design and operations.

  13. Bed bugs.

    PubMed

    Foulke, Galen T; Anderson, Bryan E

    2014-09-01

    The term bed bug is applied to 2 species of genus Cimex: lectularius describes the common or temperate bed bug, and hemipterus its tropical cousin. Cimex lectularius is aptly named; its genus and species derive from the Latin words for bug and bed, respectively. Though the tiny pest is receiving increased public attention and scrutiny, the bed bug is hardly a new problem. PMID:25577850

  14. Separation Control in a Multistage Compressor Using Impulsive Surface Injection

    NASA Technical Reports Server (NTRS)

    Wundrow, David W.; Braunscheidel, Edward P.; Culley, Dennis E.; Bright, Michelle M.

    2006-01-01

    Control of flow separation using impulsive surface injection is investigated within the multistage environment of a low speed axial-flow compressor. Measured wake profiles behind a set of embedded stator vanes treated with suction-surface injection indicate significant reduction in flow separation at a variety of injection-pulse repetition rates and durations. The corresponding total pressure losses across the vanes reveal a bank of repetition rates at each pulse duration where the separation control remains nearly complete. This persistence allows for demands on the injected-mass delivery system to be economized while still achieving effective flow control. The response of the stator-vane boundary layers to infrequently applied short injection pulses is described in terms of the periodic excitation of turbulent strips whose growth and propagation characteristics dictate the lower bound on the band of optimal pulse repetition rates. The eventual falloff in separation control at higher repetition rates is linked to a competition between the benefits of pulse-induced mixing and the aggravation caused by the periodic introduction of low-momentum fluid. Use of these observations for impulsive actuator design is discussed and their impact on modeling the time-average effect of impulsive surface injection for multistage steady-flow simulation is considered.

  15. Multi-megavolt low jitter multistage switch

    DOEpatents

    Humphreys, D.R.; Penn, K.J. Jr.

    1985-06-19

    It is one object of the present invention to provide a multistage switch capable of holding off numerous megavolts, until triggered, from a particle beam accelerator of the type used for inertial confinement fusion. The invention provides a multistage switch having low timing jitter and capable of producing multiple spark channels for spreading current over a wider area to reduce electrode damage and increase switch lifetime. The switch has fairly uniform electric fields and a short spark gap for laser triggering and is engineered to prevent insulator breakdowns.

  16. Mars integrated transportation system multistage Mars mission

    NASA Technical Reports Server (NTRS)

    1991-01-01

    In accordance with the objective of the Mars Integrated Transport System (MITS) program, the Multistage Mars Mission (MSMM) design team developed a profile for a manned mission to Mars. The purpose of the multistage mission is to send a crew of five astronauts to the martian surface by the year 2019. The mission continues man's eternal quest for exploration of new frontiers. This mission has a scheduled duration of 426 days that includes experimentation en route as well as surface exploration and experimentation. The MSMM is also designed as a foundation for a continuing program leading to the colonization of the planet Mars.

  17. Multistage Magnetic Separator of Cells and Proteins

    NASA Technical Reports Server (NTRS)

    Barton, Ken; Ainsworth, Mark; Daily, Bruce; Dunn, Scott; Metz, Bill; Vellinger, John; Taylor, Brock; Meador, Bruce

    2005-01-01

    The multistage electromagnetic separator for purifying cells and magnetic particles (MAGSEP) is a laboratory apparatus for separating and/or purifying particles (especially biological cells) on the basis of their magnetic susceptibility and magnetophoretic mobility. Whereas a typical prior apparatus based on similar principles offers only a single stage of separation, the MAGSEP, as its full name indicates, offers multiple stages of separation; this makes it possible to refine a sample population of particles to a higher level of purity or to categorize multiple portions of the sample on the basis of magnetic susceptibility and/or magnetophoretic mobility. The MAGSEP includes a processing unit and an electronic unit coupled to a personal computer. The processing unit includes upper and lower plates, a plate-rotation system, an electromagnet, an electromagnet-translation system, and a capture-magnet assembly. The plates are bolted together through a roller bearing that allows the plates to rotate with respect to each other. An interface between the plates acts as a seal for separating fluids. A lower cuvette can be aligned with as many as 15 upper cuvette stations for fraction collection during processing. A two-phase stepping motor drives the rotation system, causing the upper plate to rotate for the collection of each fraction of the sample material. The electromagnet generates a magnetic field across the lower cuvette, while the translation system translates the electromagnet upward along the lower cuvette. The current supplied to the electromagnet, and thus the magnetic flux density at the pole face of the electromagnet, can be set at a programmed value between 0 and 1,400 gauss (0.14 T). The rate of translation can be programmed between 5 and 2,000 m/s so as to align all sample particles in the same position in the cuvette. The capture magnet can be a permanent magnet. It is mounted on an arm connected to a stepping motor. The stepping motor rotates the arm to

  18. A study of multistage multifunction column for fine particle separation: Quarterly technical report, October 1, 1996 - December 31, 1996

    SciTech Connect

    Chiang, Shiao Hung

    1997-01-01

    The overall objective of the research program is to explore the potential application of a new invention involving a multistage column equipped with concentric draft-tubes (hereafter referred to as the multistage column) for fine coal cleaning and other fluid/particle separation processes. The research work will identify the design parameters and their effects on the performance of the separation process. The results of this study will provide an engineering basis for further development of this technology in coal cleaning and in the general areas of fluid/particle separation. In the last quarter, we initiated the wastewater treatment tests program to verify the multifunction features of the multistage column. The set-up of the test equipment and analytic instrument were completed. During this period, we performed a series of oily water cleaning tests.

  19. The design and development of transonic multistage compressors

    NASA Technical Reports Server (NTRS)

    Ball, C. L.; Steinke, R. J.; Newman, F. A.

    1988-01-01

    The development of the transonic multistage compressor is reviewed. Changing trends in design and performance parameters are noted. These changes are related to advances in compressor aerodynamics, computational fluid mechanics and other enabling technologies. The parameters normally given to the designer and those that need to be established during the design process are identified. Criteria and procedures used in the selection of these parameters are presented. The selection of tip speed, aerodynamic loading, flowpath geometry, incidence and deviation angles, blade/vane geometry, blade/vane solidity, stage reaction, aerodynamic blockage, inlet flow per unit annulus area, stage/overall velocity ratio, and aerodynamic losses are considered. Trends in these parameters both spanwise and axially through the machine are highlighted. The effects of flow mixing and methods for accounting for the mixing in the design process are discussed.

  20. A Multistage Approach for Image Registration.

    PubMed

    Bowen, Francis; Hu, Jianghai; Du, Eliza Yingzi

    2016-09-01

    Successful image registration is an important step for object recognition, target detection, remote sensing, multimodal content fusion, scene blending, and disaster assessment and management. The geometric and photometric variations between images adversely affect the ability for an algorithm to estimate the transformation parameters that relate the two images. Local deformations, lighting conditions, object obstructions, and perspective differences all contribute to the challenges faced by traditional registration techniques. In this paper, a novel multistage registration approach is proposed that is resilient to view point differences, image content variations, and lighting conditions. Robust registration is realized through the utilization of a novel region descriptor which couples with the spatial and texture characteristics of invariant feature points. The proposed region descriptor is exploited in a multistage approach. A multistage process allows the utilization of the graph-based descriptor in many scenarios thus allowing the algorithm to be applied to a broader set of images. Each successive stage of the registration technique is evaluated through an effective similarity metric which determines subsequent action. The registration of aerial and street view images from pre- and post-disaster provide strong evidence that the proposed method estimates more accurate global transformation parameters than traditional feature-based methods. Experimental results show the robustness and accuracy of the proposed multistage image registration methodology. PMID:26292357

  1. Phase stability in a multistage Zeeman decelerator

    NASA Astrophysics Data System (ADS)

    Wiederkehr, A. W.; Hogan, S. D.; Merkt, F.

    2010-10-01

    The phase stability of a multistage Zeeman decelerator is analyzed by numerical particle-trajectory simulations and experimental measurements. A one-dimensional model of the phase stability in multistage Stark deceleration [Bethlem , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.84.5744 84, 5744 (2000)] has been adapted to multistage Zeeman deceleration and compared with one- and three-dimensional particle-trajectory simulations, including the analysis of the effect of finite switch-on and -off times of the deceleration pulses. The comparison reveals that transverse effects in the decelerator lead to a considerable reduction of the phase-space acceptance at low values of the phase angle and an enhancement at high values. The optimal combinations of phase angles and currents with which a preset amount of kinetic energy can be removed from atoms and molecules in a pulsed supersonic beam using a multistage decelerator are determined by simulation. Quantitative analysis of the phase-space acceptance within a given volume reveals that for our decelerator (8 μs switch-off time) optimal conditions are achieved for values of the phase angle between 45° and 55°. This conclusion is examined and confirmed by experimental measurements using deuterium atoms. Alternative approaches to generate optimal deceleration pulse sequences, such as the implementation of evolutionary algorithms or the use of higher-order modes of the decelerator, are discussed.

  2. Multi-stage separations based on dielectrophoresis

    DOEpatents

    Mariella, Jr., Raymond P.

    2004-07-13

    A system utilizing multi-stage traps based on dielectrophoresis. Traps with electrodes arranged transverse to the flow and traps with electrodes arranged parallel to the flow with combinations of direct current and alternating voltage are used to trap, concentrate, separate, and/or purify target particles.

  3. Phase stability in a multistage Zeeman decelerator

    SciTech Connect

    Wiederkehr, A. W.; Hogan, S. D.; Merkt, F.

    2010-10-15

    The phase stability of a multistage Zeeman decelerator is analyzed by numerical particle-trajectory simulations and experimental measurements. A one-dimensional model of the phase stability in multistage Stark deceleration [Bethlem et al., Phys. Rev. Lett. 84, 5744 (2000)] has been adapted to multistage Zeeman deceleration and compared with one- and three-dimensional particle-trajectory simulations, including the analysis of the effect of finite switch-on and -off times of the deceleration pulses. The comparison reveals that transverse effects in the decelerator lead to a considerable reduction of the phase-space acceptance at low values of the phase angle and an enhancement at high values. The optimal combinations of phase angles and currents with which a preset amount of kinetic energy can be removed from atoms and molecules in a pulsed supersonic beam using a multistage decelerator are determined by simulation. Quantitative analysis of the phase-space acceptance within a given volume reveals that for our decelerator (8 {mu}s switch-off time) optimal conditions are achieved for values of the phase angle between 45 deg. and 55 deg. This conclusion is examined and confirmed by experimental measurements using deuterium atoms. Alternative approaches to generate optimal deceleration pulse sequences, such as the implementation of evolutionary algorithms or the use of higher-order modes of the decelerator, are discussed.

  4. Automated Simultaneous Assembly for Multistage Testing

    ERIC Educational Resources Information Center

    Breithaupt, Krista; Ariel, Adelaide; Veldkamp, Bernard P.

    2005-01-01

    This article offers some solutions used in the assembly of the computerized Uniform Certified Public Accountancy (CPA) licensing examination as practical alternatives for operational programs producing large numbers of forms. The Uniform CPA examination was offered as an adaptive multistage test (MST) beginning in April of 2004. Examples of…

  5. "MSTGen": Simulated Data Generator for Multistage Testing

    ERIC Educational Resources Information Center

    Han, Kyung T.

    2013-01-01

    Multistage testing, or MST, was developed as an alternative to computerized adaptive testing (CAT) for applications in which it is preferable to administer a test at the level of item sets (i.e., modules). As with CAT, the simulation technique in MST plays a critical role in the development and maintenance of tests. "MSTGen," a new MST…

  6. Removal of oxides of nitrogen from gases in multi-stage coal combustion

    DOEpatents

    Mollot, Darren J.; Bonk, Donald L.; Dowdy, Thomas E.

    1998-01-01

    Polluting NO.sub.x gas values are removed from off-gas of a multi-stage coal combustion process which includes an initial carbonizing reaction, firing of char from this reaction in a fluidized bed reactor, and burning of gases from the carbonizing and fluidized bed reactions in a topping combustor having a first, fuel-rich zone and a second, fuel-lean zone. The improvement by means of which NO.sub.x gases are removed is directed to introducing NO.sub.x -free oxidizing gas such as compressor air into the second, fuel-lean zone and completing combustion with this source of oxidizing gas. Excess air fed to the fluidized bed reactor is also controlled to obtain desired stoichiometry in the first, fuel-rich zone of the topping combustor.

  7. Removal of oxides of nitrogen from gases in multi-stage coal combustion

    DOEpatents

    Mollot, D.J.; Bonk, D.L.; Dowdy, T.E.

    1998-01-13

    Polluting NO{sub x} gas values are removed from off-gas of a multi-stage coal combustion process which includes an initial carbonizing reaction, firing of char from this reaction in a fluidized bed reactor, and burning of gases from the carbonizing and fluidized bed reactions in a topping combustor having a first, fuel-rich zone and a second, fuel-lean zone. The improvement by means of which NO{sub x} gases are removed is directed to introducing NO{sub x}-free oxidizing gas such as compressor air into the second, fuel-lean zone and completing combustion with this source of oxidizing gas. Excess air fed to the fluidized bed reactor is also controlled to obtain desired stoichiometry in the first, fuel-rich zone of the topping combustor. 2 figs.

  8. Numerical Study of Usage Efficiency of Multistage Filters on Mineral Leaching Process

    NASA Astrophysics Data System (ADS)

    Inkarbekov, Medet; Kuljabekov, Alibek; Alibayeva, Karlygash; Kaltayev, Aidarkhan

    2013-11-01

    The numerical study of the usage efficiency of the multistage filters setting technology is carried out on the basis of mathematical simulation. And its application on in-situ mineral leaching process is considered. So long as mineral bearing sandstone in deposit mostly is separated by interbedded layers of sands and clays, it's expedient to use multistage filters setting technology at the mineral extraction. A comparison of the extraction degree at single and multistage filters is implemented. The results of calculations show that the distribution of flow (inflow) on well height is not uniform. In the calculations the well accepted as high-permeability channel, depending on the construction of the filter. Obtained results for a multistage filters setting qualitatively conform to the experimental findings. Wellbore is considered as a surface with a constant reduced pressure in the bottomhole formation zone. But such assumption does not show a qualitative picture of the fluid flow in the bottomhole zone [Brovin K.G., Grabovnikov V.A., 1997]. To construct an accurate mathematical model it's necessary to use Navier-Stokes equation for the interior of a vertical wellbore, and the filtration law for modeling the filtration in the reservoir. Strictly speaking, it would have had to sew two laws on the contact surface of a rock and filter. Such review requires enormous computing, as far as computational grid must be sufficiently thick to cover the interior of the wellbore.

  9. Multistage hierarchy for fast image analysis

    NASA Astrophysics Data System (ADS)

    Grudin, Maxim A.; Harvey, David M.; Timchenko, Leonid I.

    1996-12-01

    In this paper, a novel approach is proposed, which allows for an efficient reduction of the amount of visual data required for representing structural information in the image. This is a multistage architecture which investigates partial correlations between structural image components. Mathematical description of the multistage hierarchical processing is provided, together with the network architecture. Initially the image is partitioned to be processed in parallel channels. In each channel, the structural components are transformed and subsequently separated, depending on their structural significance, to be then combined with the components from other channels for further processing. The output result is represented as a pattern vector, whose components are computed one at a time to allow the quickest possible response. The input gray- scale image is transformed before the processing begins, so that each pixel contains information about the spatial structure of its neighborhood. The most correlated information is extracted first, making the algorithm tolerant to minor structural changes.

  10. A Multistage Method for Multiobjective Route Selection

    NASA Astrophysics Data System (ADS)

    Wen, Feng; Gen, Mitsuo

    The multiobjective route selection problem (m-RSP) is a key research topic in the car navigation system (CNS) for ITS (Intelligent Transportation System). In this paper, we propose an interactive multistage weight-based Dijkstra genetic algorithm (mwD-GA) to solve it. The purpose of the proposed approach is to create enough Pareto-optimal routes with good distribution for the car driver depending on his/her preference. At the same time, the routes can be recalculated according to the driver's preferences by the multistage framework proposed. In the solution approach proposed, the accurate route searching ability of the Dijkstra algorithm and the exploration ability of the Genetic algorithm (GA) are effectively combined together for solving the m-RSP problems. Solutions provided by the proposed approach are compared with the current research to show the effectiveness and practicability of the solution approach proposed.

  11. Paragenesis and chemistry of multistage tourmaline formation in the sullivan Pb-Zn-Ag deposit, British Columbia

    USGS Publications Warehouse

    Jiang, S.-Y.; Palmer, M.R.; Slack, J.F.; Shaw, D.R.

    1998-01-01

    Detailed petrographic study, scanning electron microscope imaging, and electron microprobe analyses of tourmalines from the Sullivan Pb-Zn-Ag massive sulfide deposit (British Columbia, Canada) document multiple paragenetic stages and large compositional variations. The tourmalines mainly belong to two common solid-solution series: dravite-schorl and dravite-uvite. Ca- and Fe-rich feruvite and alkali-deficient tourmalines are present locally. Products of tourmaline-forming stages include (from oldest to youngest): (1) rare Fe-rich dravite-schorl within black tourmalinite clasts in footwall fragmental rocks; (2) widespread Mg-rich, very fine grained, felted dravite in the footwall (the main type of tourmaline in the footwall tourmalinite pipe); (3) recrystallized, Fe-rich dravite-schorl (locally Ca-Fe feruvite) in the tourmalinite pipe, which preferentially occurs near postore gabbroic intrusions; (4) Mg-rich dravite or uvite associated with chlorite-pyrrhotite and chlorite-albite-pyrite-altered rocks in the shallow footwall and hanging wall; (5) discrete Mg-rich tourmaline grains associated with chlorite and discordant Mg-rich tourmaline rims which occur on disseminated Fe-rich schorl in the bedded Pb-Zn-Ag ores. The timing of rare Fe-rich schorl in the bedded ores is uncertain, but it most likely occurred during or between stages 2 and 3. The different paragenetic stages and their respective tourmaline compositions are interpreted in terms of a multistage evolution involving contributions from: (1) variable mixtures of synsedimentary, Fe-rich hydrothermal fluids and entrained seawater; (2) postore, Fe-rich, gabbro-related hydrothermal fluids; and (3) postore metamorphic reactions. Early synsedimentary, Fe-rich hydrothermal fluids which contained little or no entrained seawater formed Fe-rich black tourmalinite clasts locally in the footwall. The major type of tourmaline in the footwall tourmalinite pipe is Mg rich, recording seawater entrainment under high water

  12. Impedance characteristics of multistage ion diodes

    SciTech Connect

    Desjarlais, M.

    1994-09-01

    We further develop a theory of multistage diodes that includes the possibility of emission of ions in the final stage. The exact solutions are extremely cumbersome and are not practical for most applications. We have developed approximate solutions that are very accurate, require no integrations, and may be rapidly calculated using a simple iterative scheme. These solutions for the total current as a function of voltage are used in time-dependent modeling of a two-stage diode.

  13. Handling Imbalanced Data Sets in Multistage Classification

    NASA Astrophysics Data System (ADS)

    López, M.

    Multistage classification is a logical approach, based on a divide-and-conquer solution, for dealing with problems with a high number of classes. The classification problem is divided into several sequential steps, each one associated to a single classifier that works with subgroups of the original classes. In each level, the current set of classes is split into smaller subgroups of classes until they (the subgroups) are composed of only one class. The resulting chain of classifiers can be represented as a tree, which (1) simplifies the classification process by using fewer categories in each classifier and (2) makes it possible to combine several algorithms or use different attributes in each stage. Most of the classification algorithms can be biased in the sense of selecting the most populated class in overlapping areas of the input space. This can degrade a multistage classifier performance if the training set sample frequencies do not reflect the real prevalence in the population. Several techniques such as applying prior probabilities, assigning weights to the classes, or replicating instances have been developed to overcome this handicap. Most of them are designed for two-class (accept-reject) problems. In this article, we evaluate several of these techniques as applied to multistage classification and analyze how they can be useful for astronomy. We compare the results obtained by classifying a data set based on Hipparcos with and without these methods.

  14. Multi-stage sampling in genetic epidemiology.

    PubMed

    Whittemore, A S; Halpern, J

    When data are expensive to collect, it can be cost-efficient to sample in two or more stages. In the first stage a simple random sample is drawn and then stratified according to some easily measured attribute. In each subsequent stage a random subset of previously selected units is sampled for more detailed observation, with a unit's sampling probability determined by its attributes as observed in the previous stages. These designs are useful in many medical studies; here we use them in genetic epidemiology. Two genetic studies illustrate the strengths and limitations of the approach. The first study evaluates nuclear and mitochondrial DNA in U.S. blacks. The goal is to estimate the relative contributions of white male genes and white female genes to the gene pool of African-Americans. This example shows that the Horvitz-Thompson estimators proposed for multi-stage designs can be inefficient, particularly when used with unnecessary stratification. The second example is a multi-stage study of familial prostate cancer. The goal is to gather pedigrees, blood samples and archived tissue for segregation and linkage analysis of familial prostate cancer data by first obtaining crude family data from prostate cancer cases and cancer-free controls. This second example shows the gains in efficiency from multi-stage sampling when the individual likelihood or quasilikelihood scores vary substantially across strata. PMID:9004389

  15. Biparticle fluidized bed reactor

    DOEpatents

    Scott, C.D.; Marasco, J.A.

    1995-04-25

    A fluidized bed reactor system utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figs.

  16. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.; Marasco, Joseph A.

    1995-01-01

    A fluidized bed reactor system utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves.

  17. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.; Marasco, Joseph A.

    1996-01-01

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary and tertiary particulate phases, continuously introduced and removed simultaneously in the cocurrent and countercurrent mode, act in a role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Means for introducing and removing the sorbent phases include feed screw mechanisms and multivane slurry valves.

  18. Biparticle fluidized bed reactor

    DOEpatents

    Scott, Charles D.

    1993-01-01

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves.

  19. Biparticle fluidized bed reactor

    DOEpatents

    Scott, C.D.; Marasco, J.A.

    1996-02-27

    A fluidized bed reactor system is described which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary and tertiary particulate phases, continuously introduced and removed simultaneously in the cocurrent and countercurrent mode, act in a role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Means for introducing and removing the sorbent phases include feed screw mechanisms and multivane slurry valves. 3 figs.

  20. Biparticle fluidized bed reactor

    DOEpatents

    Scott, C.D.

    1993-12-14

    A fluidized bed reactor system which utilizes a fluid phase, a retained fluidized primary particulate phase, and a migratory second particulate phase is described. The primary particulate phase is a particle such as a gel bead containing an immobilized biocatalyst. The secondary particulate phase, continuously introduced and removed in either cocurrent or countercurrent mode, acts in a secondary role such as a sorbent to continuously remove a product or by-product constituent from the fluid phase. Introduction and removal of the sorbent phase is accomplished through the use of feed screw mechanisms and multivane slurry valves. 3 figures.

  1. Advanced multistage turbine blade aerodynamics, performance, cooling, and heat transfer

    SciTech Connect

    Fleeter, S.; Lawless, P.B.

    1995-10-01

    The gas turbine has the potential for power production at the highest possible efficiency. The challenge is to ensure that gas turbines operate at the optimum efficiency so as to use the least fuel and produce minimum emissions. A key component to meeting this challenge is the turbine. Turbine performance, both aerodynamics and heat transfer, is one of the barrier advanced gas turbine development technologies. This is a result of the complex, highly three-dimensional and unsteady flow phenomena in the turbine. Improved turbine aerodynamic performance has been achieved with three-dimensional highly-loaded airfoil designs, accomplished utilizing Euler or Navier-Stokes Computational Fluid Dynamics (CFD) codes. These design codes consider steady flow through isolated blade rows. Thus they do not account for unsteady flow effects. However, unsteady flow effects have a significant impact on performance. Also, CFD codes predict the complete flow field. The experimental verification of these codes has traditionally been accomplished with point data - not corresponding plane field measurements. Thus, although advanced CFD predictions of the highly complex and three-dimensional turbine flow fields are available, corresponding data are not. To improve the design capability for high temperature turbines, a detailed understanding of the highly unsteady and three-dimensional flow through multi-stage turbines is necessary. Thus, unique data are required which quantify the unsteady three-dimensional flow through multi-stage turbine blade rows, including the effect of the film coolant flow. This requires experiments in appropriate research facilities in which complete flow field data, not only point measurements, are obtained and analyzed. Also, as design CFD codes do not account for unsteady flow effects, the next logical challenge and the current thrust in CFD code development is multiple-stage analyses that account for the interactions between neighboring blade rows.

  2. Aerodynamic Design Study of Advanced Multistage Axial Compressor

    NASA Technical Reports Server (NTRS)

    Larosiliere, Louis M.; Wood, Jerry R.; Hathaway, Michael D.; Medd, Adam J.; Dang, Thong Q.

    2002-01-01

    As a direct response to the need for further performance gains from current multistage axial compressors, an investigation of advanced aerodynamic design concepts that will lead to compact, high-efficiency, and wide-operability configurations is being pursued. Part I of this report describes the projected level of technical advancement relative to the state of the art and quantifies it in terms of basic aerodynamic technology elements of current design systems. A rational enhancement of these elements is shown to lead to a substantial expansion of the design and operability space. Aerodynamic design considerations for a four-stage core compressor intended to serve as a vehicle to develop, integrate, and demonstrate aerotechnology advancements are discussed. This design is biased toward high efficiency at high loading. Three-dimensional blading and spanwise tailoring of vector diagrams guided by computational fluid dynamics (CFD) are used to manage the aerodynamics of the high-loaded endwall regions. Certain deleterious flow features, such as leakage-vortex-dominated endwall flow and strong shock-boundary-layer interactions, were identified and targeted for improvement. However, the preliminary results were encouraging and the front two stages were extracted for further aerodynamic trimming using a three-dimensional inverse design method described in part II of this report. The benefits of the inverse design method are illustrated by developing an appropriate pressure-loading strategy for transonic blading and applying it to reblade the rotors in the front two stages of the four-stage configuration. Multistage CFD simulations based on the average passage formulation indicated an overall efficiency potential far exceeding current practice for the front two stages. Results of the CFD simulation at the aerodynamic design point are interrogated to identify areas requiring additional development. In spite of the significantly higher aerodynamic loadings, advanced CFD

  3. Multistage Schemes with Multigrid for Euler and Navier-Strokes Equations: Components and Analysis

    NASA Technical Reports Server (NTRS)

    Swanson, R. C.; Turkel, Eli

    1997-01-01

    A class of explicit multistage time-stepping schemes with centered spatial differencing and multigrids are considered for the compressible Euler and Navier-Stokes equations. These schemes are the basis for a family of computer programs (flow codes with multigrid (FLOMG) series) currently used to solve a wide range of fluid dynamics problems, including internal and external flows. In this paper, the components of these multistage time-stepping schemes are defined, discussed, and in many cases analyzed to provide additional insight into their behavior. Special emphasis is given to numerical dissipation, stability of Runge-Kutta schemes, and the convergence acceleration techniques of multigrid and implicit residual smoothing. Both the Baldwin and Lomax algebraic equilibrium model and the Johnson and King one-half equation nonequilibrium model are used to establish turbulence closure. Implementation of these models is described.

  4. 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

  5. Study of ebullated-bed fluid dynamics for h-coal. Quarterly progress report No. 2, October 1-December 31, 1980

    SciTech Connect

    Schaefer, R. J.; Rundell, D. N.

    1981-01-01

    Analysis of data from the fluid dynamics tests performed at Hydrocarbon Research, Inc., during Run PDU-10 was started. Data in the computer files were cross-checked with the original notebooks to verify accuracy. Gamma-ray mass absorption coefficients for material in the PDU reactor were calculated using characterization of selected oil and catalyst samples. Battelle Institute began viscosity measurement of PDU reactor liquid samples. Northwestern University began shakedown of the 6'' diameter test stand. Model fluids were selected and charged to the unit. Optical components were designed and assembly was started.

  6. GREENHOUSE GAS EMISSIONS CONTROL BY OXYGEN FIRING IN CIRCULATING FLUID BED BOILERS (Phase II--Evaluation of the Oxyfuel CFB Concept)

    SciTech Connect

    John L. Marion; Nsakala ya Nsakala

    2003-11-09

    The overall project goal is to determine if carbon dioxide can be captured and sequestered at a cost of about $10/ton of carbon avoided, using a newly constructed Circulating Fluidized Bed combustor while burning coal with a mixture of oxygen and recycled flue gas, instead of air. This project is structured in two Phases. Phase I was performed between September 28, 2001 and May 15, 2002. Results from Phase I were documented in a Topical Report issued on May 15, 2003 (Nsakala, et al., 2003), with the recommendation to evaluate, during Phase II, the Oxyfuel-fired CFB concept. DOE NETL accepted this recommendation, and, hence approved the project continuation into Phase II. Phase 2. The second phase of the project--which includes pilot-scale tests of an oxygen-fired circulating fluidized bed test facility with performance and economic analyses--is currently underway at ALSTOM's Power Plant Laboratories, located in Windsor, CT (US). The objective of the pilot-scale testing is to generate detailed technical data needed to establish advanced CFB design requirements and performance when firing coals and delayed petroleum coke in oxygen/carbon dioxide mixtures. Results will be used in the design of oxygen-fired CFB boilers--both retrofit and new Greenfield--as well as to provide a generic performance database for other researchers. At the conclusion of Phase 2, revised costs and performance will be estimated for both retrofit and new Greenfield design concepts with CO2 capture, purification, compression, and liquefaction.

  7. Multistage Zeeman deceleration of metastable neon.

    PubMed

    Wiederkehr, Alex W; Motsch, Michael; Hogan, Stephen D; Andrist, Markus; Schmutz, Hansjürg; Lambillotte, Bruno; Agner, Josef A; Merkt, Frédéric

    2011-12-01

    A supersonic beam of metastable neon atoms has been decelerated by exploiting the interaction between the magnetic moment of the atoms and time-dependent inhomogeneous magnetic fields in a multistage Zeeman decelerator. Using 91 deceleration solenoids, the atoms were decelerated from an initial velocity of 580 m/s to final velocities as low as 105 m/s, corresponding to a removal of more than 95% of their initial kinetic energy. The phase-space distribution of the cold, decelerated atoms was characterized by time-of-flight and imaging measurements, from which a temperature of 10 mK was obtained in the moving frame of the decelerated sample. In combination with particle-trajectory simulations, these measurements allowed the phase-space acceptance of the decelerator to be quantified. The degree of isotope separation that can be achieved by multistage Zeeman deceleration was also studied by performing experiments with pulse sequences generated for (20)Ne and (22)Ne. PMID:22149785

  8. Multistage adsorption of diffusing macromolecules and viruses

    NASA Astrophysics Data System (ADS)

    Chou, Tom; D'Orsogna, Maria R.

    2007-09-01

    We derive the equations that describe adsorption of diffusing particles onto a surface followed by additional surface kinetic steps before being transported across the interface. Multistage surface kinetics occurs during membrane protein insertion, cell signaling, and the infection of cells by virus particles. For example, viral entry into healthy cells is possible only after a series of receptor and coreceptor binding events occurs at the cellular surface. We couple the diffusion of particles in the bulk phase with the multistage surface kinetics and derive an effective, integrodifferential boundary condition that contains a memory kernel embodying the delay induced by the surface reactions. This boundary condition takes the form of a singular perturbation problem in the limit where particle-surface interactions are short ranged. Moreover, depending on the surface kinetics, the delay kernel induces a nonmonotonic, transient replenishment of the bulk particle concentration near the interface. The approach generalizes that of Ward and Tordai [J. Chem. Phys. 14, 453 (1946)] and Diamant and Andelman [Colloids Surf. A 183-185, 259 (2001)] to include surface kinetics, giving rise to qualitatively new behaviors. Our analysis also suggests a simple scheme by which stochastic surface reactions may be coupled to deterministic bulk diffusion.

  9. Multistage Zeeman deceleration of metastable neon

    SciTech Connect

    Wiederkehr, Alex W.; Motsch, Michael; Hogan, Stephen D.; Andrist, Markus; Schmutz, Hansjuerg; Lambillotte, Bruno; Agner, Josef A.; Merkt, Frederic

    2011-12-07

    A supersonic beam of metastable neon atoms has been decelerated by exploiting the interaction between the magnetic moment of the atoms and time-dependent inhomogeneous magnetic fields in a multistage Zeeman decelerator. Using 91 deceleration solenoids, the atoms were decelerated from an initial velocity of 580 m/s to final velocities as low as 105 m/s, corresponding to a removal of more than 95% of their initial kinetic energy. The phase-space distribution of the cold, decelerated atoms was characterized by time-of-flight and imaging measurements, from which a temperature of 10 mK was obtained in the moving frame of the decelerated sample. In combination with particle-trajectory simulations, these measurements allowed the phase-space acceptance of the decelerator to be quantified. The degree of isotope separation that can be achieved by multistage Zeeman deceleration was also studied by performing experiments with pulse sequences generated for {sup 20}Ne and {sup 22}Ne.

  10. Solar heated fluidized bed gasification system

    NASA Technical Reports Server (NTRS)

    Qader, S. A. (Inventor)

    1981-01-01

    A solar-powered fluidized bed gasification system for gasifying carbonaceous material is presented. The system includes a solar gasifier which is heated by fluidizing gas and steam. Energy to heat the gas and steam is supplied by a high heat capacity refractory honeycomb which surrounds the fluid bed reactor zone. The high heat capacity refractory honeycomb is heated by solar energy focused on the honeycomb by solar concentrator through solar window. The fluid bed reaction zone is also heated directly and uniformly by thermal contact of the high heat capacity ceramic honeycomb with the walls of the fluidized bed reactor. Provisions are also made for recovering and recycling catalysts used in the gasification process. Back-up furnace is provided for start-up procedures and for supplying heat to the fluid bed reaction zone when adequate supplies of solar energy are not available.

  11. Exposure Control Using Adaptive Multi-Stage Item Bundles.

    ERIC Educational Resources Information Center

    Luecht, Richard M.

    This paper presents a multistage adaptive testing test development paradigm that promises to handle content balancing and other test development needs, psychometric reliability concerns, and item exposure. The bundled multistage adaptive testing (BMAT) framework is a modification of the computer-adaptive sequential testing framework introduced by…

  12. 40 CFR 600.316-78 - Multistage manufacture.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and Later Model Year Automobiles-Labeling § 600.316-78 Multistage manufacture. Where more than one person is the manufacturer of a vehicle, the final stage vehicle manufacturer (as defined in 49 CFR 549.3... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Multistage manufacture....

  13. 40 CFR 600.316-78 - Multistage manufacture.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and Later Model Year Automobiles-Labeling § 600.316-78 Multistage manufacture. Where more than one person is the manufacturer of a vehicle, the final stage vehicle manufacturer (as defined in 49 CFR 549.3... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Multistage manufacture....

  14. 40 CFR 600.316-08 - Multistage manufacture.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Multistage manufacture. Where more than one person is the manufacturer of a vehicle, the final stage manufacturer (as defined in 49 CFR 529.3) is treated as the vehicle manufacturer for purposes of compliance... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Multistage manufacture....

  15. Integrated Low Emissions Cleanup system for direct coal fueled turbines (moving bed, fluid contactor/ceramic filter). Twenty-second quarterly status report, January--March 1993

    SciTech Connect

    Newby, R.A.; Alvin, M.A.; Bachovchin, D.M.; Yang, W.C.; Smeltzer, E.E.; Lippert, T.E.

    1993-10-01

    The United States Department of Energy, Morgantown Energy Research Center (DOE/METC), is sponsoring the development of direct coal-fired turbine power plants as part of their Heat Engines program. A major technical challenge remaining for the development of the direct coal-fired turbine is high-temperature combustion gas cleaning to meet environmental standards for sulfur oxides and particulate emissions, as well as to provide acceptable turbine life. The Westinghouse Electric Corporation, Science & Technology Center, is evaluating two Integrated Low Emissions Cleanup (ILEC) concepts that have been configured to meet this technical challenge: A baseline ceramic barrier filter ILEC concept, and a fluidized bed ILEC concept. These ILEC concepts simultaneously control sulfur, particulate, and alkali contaminants in the high-pressure combustion gases at turbine inlet temperatures up to 2300{degrees}F. This document reports the status of a program in the nineteenth quarter to develop this ILEC technology for direct coal-fired turbine power plants.

  16. Biologically based multistage modeling of radiation effects

    SciTech Connect

    William Hazelton; Suresh Moolgavkar; E. Georg Luebeck

    2005-08-30

    This past year we have made substantial progress in modeling the contribution of homeostatic regulation to low-dose radiation effects and carcinogenesis. We have worked to refine and apply our multistage carcinogenesis models to explicitly incorporate cell cycle states, simple and complex damage, checkpoint delay, slow and fast repair, differentiation, and apoptosis to study the effects of low-dose ionizing radiation in mouse intestinal crypts, as well as in other tissues. We have one paper accepted for publication in ''Advances in Space Research'', and another manuscript in preparation describing this work. I also wrote a chapter describing our combined cell-cycle and multistage carcinogenesis model that will be published in a book on stochastic carcinogenesis models edited by Wei-Yuan Tan. In addition, we organized and held a workshop on ''Biologically Based Modeling of Human Health Effects of Low dose Ionizing Radiation'', July 28-29, 2005 at Fred Hutchinson Cancer Research Center in Seattle, Washington. We had over 20 participants, including Mary Helen Barcellos-Hoff as keynote speaker, talks by most of the low-dose modelers in the DOE low-dose program, experimentalists including Les Redpath (and Mary Helen), Noelle Metting from DOE, and Tony Brooks. It appears that homeostatic regulation may be central to understanding low-dose radiation phenomena. The primary effects of ionizing radiation (IR) are cell killing, delayed cell cycling, and induction of mutations. However, homeostatic regulation causes cells that are killed or damaged by IR to eventually be replaced. Cells with an initiating mutation may have a replacement advantage, leading to clonal expansion of these initiated cells. Thus we have focused particularly on modeling effects that disturb homeostatic regulation as early steps in the carcinogenic process. There are two primary considerations that support our focus on homeostatic regulation. First, a number of epidemiologic studies using multistage

  17. Physiology Of Prolonged Bed Rest

    NASA Technical Reports Server (NTRS)

    Greenleaf, John E.

    1991-01-01

    Report describes physiological effects of prolonged bed rest. Rest for periods of 24 hours or longer deconditions body to some extent; healing proceeds simultaneously with deconditioning. Report provides details on shifts in fluid electrolytes and loss of lean body mass, which comprises everything in body besides fat - that is, water, muscle, and bone. Based on published research.

  18. Multistaged stokes injected Raman capillary waveguide amplifier

    DOEpatents

    Kurnit, Norman A.

    1980-01-01

    A multistaged Stokes injected Raman capillary waveguide amplifier for providing a high gain Stokes output signal. The amplifier uses a plurality of optically coupled capillary waveguide amplifiers and one or more regenerative amplifiers to increase Stokes gain to a level sufficient for power amplification. Power amplification is provided by a multifocused Raman gain cell or a large diameter capillary waveguide. An external source of CO.sub.2 laser radiation can be injected into each of the capillary waveguide amplifier stages to increase Raman gain. Devices for injecting external sources of CO.sub.2 radiation include: dichroic mirrors, prisms, gratings and Ge Brewster plates. Alternatively, the CO.sub.2 input radiation to the first stage can be coupled and amplified between successive stages.

  19. Modern multistage depressed collectors - A review

    NASA Technical Reports Server (NTRS)

    Kosmahl, H. G.

    1982-01-01

    The design and performance of the Lewis Research Center (LeRC) electrostatic collector and the associated passive permanent magnetic beam reconditioning (refocusing) are discussed and compared with numerous experimental results on wide- and narrow-band TWT and two klystron cases. Universal designs for efficient collectors for TV klystrons are presented. Collectors other than those based on the symmetric LeRC concept are reviewed only briefly, either because they have not been treated analytically or because only sporadic or incomplete experimental evaluation results are available. It is concluded that significant, a priori predictable performance improvements for TWTs have been demonstrated and that a substantial reduction in the dc power input to TV klystron transmitters could be effected by using well-designed multistage depressed collectors.

  20. Vibration signature analysis of multistage gear transmission

    NASA Technical Reports Server (NTRS)

    Choy, F. K.; Tu, Y. K.; Savage, M.; Townsend, D. P.

    1989-01-01

    An analysis is presented for multistage multimesh gear transmission systems. The analysis predicts the overall system dynamics and the transmissibility to the gear box or the enclosed structure. The modal synthesis approach of the analysis treats the uncoupled lateral/torsional model characteristics of each stage or component independently. The vibration signature analysis evaluates the global dynamics coupling in the system. The method synthesizes the interaction of each modal component or stage with the nonlinear gear mesh dynamics and the modal support geometry characteristics. The analysis simulates transient and steady state vibration events to determine the resulting torque variations, speeds, changes, rotor imbalances, and support gear box motion excitations. A vibration signature analysis examines the overall dynamic characteristics of the system, and the individual model component responses. The gear box vibration analysis also examines the spectral characteristics of the support system.

  1. Modern multistage depressed collectors - A review

    NASA Astrophysics Data System (ADS)

    Kosmahl, H. G.

    1982-11-01

    The design and performance of the Lewis Research Center (LeRC) electrostatic collector and the associated passive permanent magnetic beam reconditioning (refocusing) are discussed and compared with numerous experimental results on wide- and narrow-band TWT and two klystron cases. Universal designs for efficient collectors for TV klystrons are presented. Collectors other than those based on the symmetric LeRC concept are reviewed only briefly, either because they have not been treated analytically or because only sporadic or incomplete experimental evaluation results are available. It is concluded that significant, a priori predictable performance improvements for TWTs have been demonstrated and that a substantial reduction in the dc power input to TV klystron transmitters could be effected by using well-designed multistage depressed collectors.

  2. Bed Bugs FAQs

    MedlinePlus

    ... Tropical Diseases Laboratory Diagnostic Assistance [DPDx] Parasites Home Bed Bugs FAQs Recommend on Facebook Tweet Share Compartir On ... are bed bugs treated and prevented? What are bed bugs? Bed bugs ( Cimex lectularius ) are small, flat, parasitic ...

  3. Dynamic bed reactor

    SciTech Connect

    Stormo, K.E.

    1996-07-02

    A dynamic bed reactor is disclosed in which a compressible open cell foam matrix is periodically compressed and expanded to move a liquid or fluid through the matrix. In preferred embodiments, the matrix contains an active material such as an enzyme, biological cell, chelating agent, oligonucleotide, adsorbent or other material that acts upon the liquid or fluid passing through the matrix. The active material may be physically immobilized in the matrix, or attached by covalent or ionic bonds. Microbeads, substantially all of which have diameters less than 50 microns, can be used to immobilize the active material in the matrix and further improve reactor efficiency. A particularly preferred matrix is made of open cell polyurethane foam, which adsorbs pollutants such as polychlorophenol or o-nitrophenol. The reactors of the present invention allow unidirectional non-laminar flow through the matrix, and promote intimate exposure of liquid reactants to active agents such as microorganisms immobilized in the matrix. 27 figs.

  4. Dynamic bed reactor

    DOEpatents

    Stormo, Keith E.

    1996-07-02

    A dynamic bed reactor is disclosed in which a compressible open cell foam matrix is periodically compressed and expanded to move a liquid or fluid through the matrix. In preferred embodiments, the matrix contains an active material such as an enzyme, biological cell, chelating agent, oligonucleotide, adsorbent or other material that acts upon the liquid or fluid passing through the matrix. The active material may be physically immobilized in the matrix, or attached by covalent or ionic bonds. Microbeads, substantially all of which have diameters less than 50 microns, can be used to immobilize the active material in the matrix and further improve reactor efficiency. A particularly preferred matrix is made of open cell polyurethane foam, which adsorbs pollutants such as polychlorophenol or o-nitrophenol. The reactors of the present invention allow unidirectional non-laminar flow through the matrix, and promote intimate exposure of liquid reactants to active agents such as microorganisms immobilized in the matrix.

  5. Multi-stage internal gear/turbine fuel pump

    DOEpatents

    Maier, Eugen; Raney, Michael Raymond

    2004-07-06

    A multi-stage internal gear/turbine fuel pump for a vehicle includes a housing having an inlet and an outlet and a motor disposed in the housing. The multi-stage internal gear/turbine fuel pump also includes a shaft extending axially and disposed in the housing. The multi-stage internal gear/turbine fuel pump further includes a plurality of pumping modules disposed axially along the shaft. One of the pumping modules is a turbine pumping module and another of the pumping modules is a gerotor pumping module for rotation by the motor to pump fuel from the inlet to the outlet.

  6. Combustion in fluidized beds

    SciTech Connect

    Dry, F.J.; La Nauze, R.D. )

    1990-07-01

    Circulating fluidized-bed (CFB) combustion systems have become popular since the late 1970s, and, given the current level of activity in the area,it is clear that this technology has a stable future in the boiler market. For standard coal combustion applications, competition is fierce with mature pulverized-fuel-based (PF) technology set to maintain a strong profile. CFB systems, however, can be more cost effective than PF systems when emission control is considered, and, as CFB technology matures, it is expected that an ever-increasing proportion of boiler installations will utilize the CFB concept. CFB systems have advantages in the combustion of low-grade fuels such as coal waste and biomass. In competition with conventional bubbling beds, the CFB boiler often demonstrates superior carbon burn-out efficiency. The key to this combustion technique is the hydrodynamic behavior of the fluidized bed. This article begins with a description of the fundamental fluid dynamic behavior of the CFB system. This is followed by an examination of the combustion process in such an environment and a discussion of the current status of the major CFB technologies.

  7. Inter-bed fluid triggered slope failures of the Kaoping Canyon upstream area: Results from memorial R/V Ocean Researcher 5

    NASA Astrophysics Data System (ADS)

    Yeh, Yi-Ching; Shen, Tsung-Fu; Liu, Shao-Yung; Yu, Pai-Sen

    2015-04-01

    As a major pathway of the sediment transportation, the submarine canyons sculpture the seafloor then deposit sediments at the deep ocean. The submarine canyons could be classified to two categories: erosive or deposition based on geological environment or fluid flow down to the canyon. The erosive canyons often 'attack' the levee which may result in submarine landslides or mass transportations due to slope failure. Once slope failure occurs at geological weakness area such as gas hydrate dissociation zone, giant mass slumping will be triggered. These kinds of mass transportations will further develop turbidity current or hyperpycnal flow, which could damage the submarine cables or pipes. The giant mass transportation even triggers devastated tsunami. In this study, a latest swath bathymetric map was compiled by comprising seven cruises between December, 2012 and March 2013. The result shows that regressive erosion may take a place north of 500 meters contour (gas hydrate dissociation region), southwest off Taiwan. Moreover, high resolution seismic image (acquired by Edgetech SB-424 sub-bottom profiler) show that gas rich sediments co-exist with submarine landslide deposits in the edge of the upstream of Kaoping submarine canyon. It implies that slope failures in the study area might be caused by weaken sediment collapse.

  8. Staged cascade fluidized bed combustor

    DOEpatents

    Cannon, Joseph N.; De Lucia, David E.; Jackson, William M.; Porter, James H.

    1984-01-01

    A fluid bed combustor comprising a plurality of fluidized bed stages interconnected by downcomers providing controlled solids transfer from stage to stage. Each stage is formed from a number of heat transfer tubes carried by a multiapertured web which passes fluidizing air to upper stages. The combustor cross section is tapered inwardly from the middle towards the top and bottom ends. Sorbent materials, as well as non-volatile solid fuels, are added to the top stages of the combustor, and volatile solid fuels are added at an intermediate stage.

  9. Catalytic multi-stage process for hydroconversion and refining hydrocarbon feeds

    DOEpatents

    Comolli, Alfred G.; Lee, Lap-Keung

    2001-01-01

    A multi-stage catalytic hydrogenation and hydroconversion process for heavy hydrocarbon feed materials such as coal, heavy petroleum fractions, and plastic waste materials. In the process, the feedstock is reacted in a first-stage, back-mixed catalytic reactor with a highly dispersed iron-based catalyst having a powder, gel or liquid form. The reactor effluent is pressure-reduced, vapors and light distillate fractions are removed overhead, and the heavier liquid fraction is fed to a second stage back-mixed catalytic reactor. The first and second stage catalytic reactors are operated at 700-850.degree. F. temperature, 1000-3500 psig hydrogen partial pressure and 20-80 lb./hr per ft.sup.3 reactor space velocity. The vapor and light distillates liquid fractions removed from both the first and second stage reactor effluent streams are combined and passed to an in-line, fixed-bed catalytic hydrotreater for heteroatom removal and for producing high quality naphtha and mid-distillate or a full-range distillate product. The remaining separator bottoms liquid fractions are distilled at successive atmospheric and vacuum pressures, low and intermediate-boiling hydrocarbon liquid products are withdrawn, and heavier distillate fractions are recycled and further upgraded to provide additional low-boiling hydrocarbon liquid products. This catalytic multistage hydrogenation process provides improved flexibility for hydroprocessing the various carbonaceous feedstocks and adjusting to desired product structures and for improved economy of operations.

  10. Solving a multistage partial inspection problem using genetic algorithms

    SciTech Connect

    Heredia-Langner, Alejandro ); Montgomery, D C.; Carlyle, W M.

    2002-01-01

    Traditionally, the multistage inspection problem has been formulated as consisting of a decision schedule where some manufacturing stages receive full inspection and the rest none. Dynamic programming and heuristic methods (like local search) are the most commonly used solution techniques. A highly constrained multistage inspection problem is presented where all stages must receive partial rectifying inspection and it is solved using a real-valued genetic algorithm. This solution technique can handle multiple objectives and quality constraints effectively.