Science.gov

Sample records for recirculation sump performance

  1. Containment-emergency-sump performance. Technical findings related to Unresolved Safety Issue A-43. [PWR

    SciTech Connect

    Not Available

    1983-04-01

    This report summarizes key technical findings related to the Unresolved Safety Issue A-43, Containment Emergency Sump Performance, and provides recommendations for resolution of attendant safety issues. The key safety questions relate to: (a) effects of insulation debris on sump performance; (b) sump hydraulic performance as determined by design features, submergence, and plant induced effects, and (c) recirculation pump performance wherein air and/or particulate ingestion can occur. The technical findings presented in this report provide information relevant to the design and performance evaluation of the containment emergency sump.

  2. Results of vortex-suppressor tests, single-outlet sump tests and miscellaneous sensitivity tests. Containment sump reliability studies generic task A-43. [PWR; BWR

    SciTech Connect

    Padmanabhan, M.

    1982-09-01

    Full scale tests of flow conditions in Containment Recirculation Sumps for nuclear power stations were conducted at the Alden Research Laboratory (ARL) of Worcester Polytechnic Institute (WPI) to provide sump hydraulic design and performance data for use in resolving the Unresolved Safety Issue, A-43, Containment Sump Performance. This document is a report of the results of investigations conducted as a part of Phase II of the test program, including: (a) vortex suppressor tests to study in detail the hydraulic behavior of two commonly used suppressors; namely, cubic cage and horizontal floor grating; (b) single outlet sump tests to ascertain the hydraulic performance of single outlet sumps compared to double outlet sumps; and (c) tests to study the effects on the hydraulic performance of a solid partition wall in a double outlet sump, pump overspeed (i.e., higher flow), outlet pipe diameter, and bellmouth entrances.

  3. Containment Sump Neutralization Using Trisodium Phosphate: Parametric Analysis

    SciTech Connect

    Zaki, Tarek G.

    2002-07-01

    For post-LOCA conditions, the pH of the aqueous solution collected in the containment sump after completion of injection of containment spray and ECC water, and all additives for reactivity control, fission product removal, and other purposes, should be maintained at a level sufficiently high to provide assurance that significant long-term iodine re-evolution does not occur. Long-term iodine retention may be assumed only when the equilibrium sump solution pH is above 7. This pH value should be achieved by the onset of the spray recirculation mode. A trisodium phosphate (TSP)-based, passive system can be used to achieve this pH value. This is a proven technology that is already in use in nuclear power plants. This system consists of several wire mesh baskets, filled with TSP and strategically located in the sump in order to insure timely dissolution of TSP and rapid pH rise under LOCA conditions. Accurate determination of the total quantity of TSP required to raise the pH of borated water in the sump to within the acceptable range is the key element to a proper design of this system. However, this type of analysis is quite involved and highly iterative, which requires the use of a computer program. This paper describes the basis for a computer program that determines the required quantity of TSP as a function of the quantity of borated water in the sump, the boron concentration, the sump temperature, and the specified pH value. The equilibrium quantities of boric acid species are calculated iteratively based on its molal equilibrium quotients. The equilibrium quantities of phosphoric acid species are calculated iteratively based on its dissociation constants. The charge balance error (CBE) is the sum of ionic charges for all species and ions in the solution, including sodium. All species are in equilibrium when the CBE reduces to zero. The paper also presents the results of a parametric analysis that is performed using this computer program. Ranges of borated water

  4. SUMP MEASURING SYSTEM

    SciTech Connect

    Vrettos, N; Athneal Marzolf, A; Casandra Robinson, C; James Fiscus, J; Daniel Krementz, D; Thomas Nance, T

    2007-11-26

    The process sumps in H-Canyon at the Savannah River Site (SRS) collect leaks from process tanks and jumpers. To prevent build-up of fissile material the sumps are frequently flushed which generates liquid waste and is prone to human error. The development of inserts filled with a neutron poison will allow a reduction in the frequency of flushing. Due to concrete deterioration and deformation of the sump liners the current dimensions of the sumps are unknown. Knowledge of these dimensions is necessary for development of the inserts. To solve this problem a remote Sump Measurement System was designed, fabricated, and tested to aid development of the sump inserts.

  5. Towards Non-thrombogenic Performance of Blood Recirculating Devices

    PubMed Central

    Bluestein, D.; Chandran, K. B.; Manning, K. B.

    2010-01-01

    Implantable blood recirculating devices have provided life saving solutions to patients with severe cardiovascular diseases. However, common problems of hemolysis and thromboembolism remain an impediment to these devices. In this article, we present a brief review of the work by several groups in the field that has led to the development of new methodologies that may facilitate achieving the daunting goal of optimizing the thrombogenic performance of blood recirculating devices. The aim is to describe work which pertains to the interaction between flow-induced stresses and the blood constituents, and that supports the hypothesis that thromboembolism in prosthetic blood recirculating devices is initiated and maintained primarily by the non-physiological flow patterns and stresses that activate and enhance the aggregation of blood platelets, increasing the risk of thromboembolism and cardioembolic stroke. Such work includes state-of-the-art numerical and experimental tools used to elucidate flow-induced mechanisms leading to thromboembolism in prosthetic devices. Following the review, the paper describes several efforts conducted by some of the groups active in the field, and points to several directions that should be pursued in the future in order to achieve the goal for blood recirculating prosthetic devices becoming more effective as destination therapy in the future. PMID:20131098

  6. Aircraft Engine Sump Fire Mitigation

    NASA Technical Reports Server (NTRS)

    Rosenlieb, J. W.

    1973-01-01

    An investigation was performed of the conditions in which fires can result and be controlled within the bearing sump simulating that of a gas turbine engine; Esso 4040 Turbo Oil, Mobil Jet 2, and Monsanto MCS-2931 lubricants were used. Control variables include the oil inlet temperature, bearing temperature, oil inlet and scavenge rates, hot air inlet temperature and flow rate, and internal sump baffling. In addition to attempting spontaneous combustion, an electric spark and a rub (friction) mechanism were employed to ignite fires. Spontaneous combustion was not obtained; however, fires were readily ignited with the electric spark while using each of the three test lubricants. Fires were also ignited using the rub mechanism with the only test lubricant evaluated, Esso 4040. Major parameters controlling ignitions were: Sump configuration; Bearing and oil temperatures, hot air temperature and flow and bearing speed. Rubbing between stationary parts and rotating parts (eg. labyrinth seal and mating rub strip) is a very potent fire source suggesting that observed accidental fires in gas turbine sumps may well arise from this cause.

  7. Self-Recirculating Casing Treatment Concept for Enhanced Compressor Performance

    NASA Technical Reports Server (NTRS)

    Hathaway, Michael D.

    2002-01-01

    A state-of-the-art CFD code (APNASA) was employed in a computationally based investigation of the impact of casing bleed and injection on the stability and performance of a moderate speed fan rotor wherein the stalling mass flow is controlled by tip flow field breakdown. The investigation was guided by observed trends in endwall flow characteristics (e.g., increasing endwall aerodynamic blockage) as stall is approached and based on the hypothesis that application of bleed or injection can mitigate these trends. The "best" bleed and injection configurations were then combined to yield a self-recirculating casing treatment concept. The results of this investigation yielded: 1) identification of the fluid mechanisms which precipitate stall of tip critical blade rows, and 2) an approach to recirculated casing treatment which results in increased compressor stall range with minimal or no loss in efficiency. Subsequent application of this approach to a high speed transonic rotor successfully yielded significant improvements in stall range with no loss in compressor efficiency.

  8. At 750 Gallery, (sump level) view of drain to sump ...

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

    At 750 Gallery, (sump level) view of drain to sump pumps, looking north. This level contains the "art gallery" which features graffiti from the 1940s-1990s. - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

  9. Effect of irradiation on nonlinear optical recirculation cavity performance

    NASA Astrophysics Data System (ADS)

    Saitta, M.; Tikhoplav, R.; Jovanovic, I.

    2012-02-01

    In applications such as the production of hydrogen ions for accelerators in spallation neutron sources, charge stripping of hydrogen ions using high-power lasers represents an attractive technical approach. The use of laser-ion interaction in conjunction with a laser recirculation cavity holds promise for improved efficiency, but the high-radiation environment raises concerns about the longevity of the key components of such a system, especially the nonlinear crystal used for frequency conversion. We present the results of an in-reactor irradiation experiment in which a sample beta-barium borate crystal has been irradiated with fast neutrons and gamma-rays, accompanied with the Monte Carlo analysis of the irradiation dose and its comparison with typical conditions at the Spallation Neutron Source at Oak Ridge National Laboratory. The results suggest that our design of the laser recirculation cavity exhibits a radiation hardness consistent with maintaining enhancement factors of the order of 10 over >10 years, but a more detailed experimental study is needed to investigate the radiation hardness of cavity designs exhibiting greater enhancement factors.

  10. Performance model of a recirculating stack nickel hydrogen cell

    NASA Technical Reports Server (NTRS)

    Zimmerman, Albert H.

    1994-01-01

    A theoretical model of the nickel hydrogen battery cell has been utilized to describe the chemical and physical changes during charge and overcharge in a recirculating stack nickel hydrogen cell. In particular, the movement of gas and electrolyte have been examined as a function of the amount of electrolyte put into the cell stack during cell activation, and as a function of flooding in regions of the gas screen in this cell design. Additionally, a two-dimensional variation on this model has been utilized to describe the effects of non-uniform loading in the nickel-electrode on the movement of gas and electrolyte within the recirculating stack nickel hydrogen cell. The type of nonuniform loading that has been examined here is that associated with higher than average loading near the surface of the sintered nickel electrode, a condition present to some degree in many nickel electrodes made by electrochemical impregnation methods. The effects of high surface loading were examined primarily under conditions of overcharge, since the movement of gas and electrolyte in the overcharging condition was typically where the greatest effects of non-uniform loading were found. The results indicate that significant changes in the capillary forces between cell components occur as the percentage of free volume in the stack filled by electrolyte becomes very high. These changes create large gradients in gas-filled space and oxygen concentrations near the boundary between the separator and the hydrogen electrode when the electrolyte fill is much greater than about 95 percent of the stack free volume. At lower electrolyte fill levels, these gaseous and electrolyte gradients become less extreme, and shift through the separator towards the nickel electrode. Similarly, flooding of areas in the gas screen cause higher concentrations of oxygen gas to approach the platinum/hydrogen electrode that is opposite the back side of the nickel electrode. These results illustrate the need for

  11. Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a recirculating control loop which had no water quality maintenance. Results show that periodic water maintenance can improve performance of the SWME. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage of this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing sublimator technology. The driver for the evaluation of water recirculation maintenance components was to enhance the robustness of the SWME through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A patented bed design that was developed for a United Technologies Aerospace System military application provided a low pressure drop means for water maintenance in the SWME recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for the ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  12. Environmental performance of air staged combustor with flue gas recirculation to burn coal/biomass

    SciTech Connect

    Anuar, S.H.; Keener, H.M.

    1995-12-31

    The environmental and thermal performance of a 1.07 m diameter, 440 kW atmospheric fluidized bed combustor operated at 700{degrees}C-920{degrees}C and burning coal was studied. Flue gas recirculation was incorporated to enhance the thermal performance and air staging was used to control emissions of SO{sub 2}, CO, NO{sub x} and N{sub 2}O. Studies focused on the effect of excess air, firing rate, and use of sorbent on system performance. The recirculation-staging mode with limestone had the highest thermal efficiency (0.67) using the firing equation. Emission data showed that flue gas recirculation (ratio of 0.7) significantly reduced NO{sub x} emissions; and that use of limestone sorbent at a Ca/S ratio of 3 reduced SO{sub 2} emissions by 64% to approximately 0.310 g/MJ.

  13. Effects of anti-recirculation ring on performance of an automotive cooling fan

    NASA Astrophysics Data System (ADS)

    Chen, Q. G.; Zhang, Y. C.; Li, F.; Kong, X. Z.; Luan, X. H.

    2013-12-01

    An investigation has been conducted to evaluate the effects of anti-recirculation ring on performance of automotive axial flow cooling fan by CFD simulation. In order to reduce the element size and save computing time, periodic boundary condition and single flow channel has been applied to the simulation. The grid is composed of tetrahedral mesh and hexahedral mesh. The SST k - ω turbulence model and standard wall function method have been used. CFD results show that optimal design of pressure loss anti-recirculation ring can not only increase P-Q performance and aerodynamic efficiency, but also can improve the pressure distribution on fan tip which can reduce the axial deformation of cooling fan. So it can be proved that good design of anti-recirculation ring will not increase the total axial size of an axial cooling fan.

  14. Dry sump crankcase

    SciTech Connect

    Berger, A.H.; Dichi, R.E.

    1987-06-23

    A dry sump type crankcase is described for an automotive type internal combustion engine having an intake manifold and a positive crankcase ventilation (PCV) system for automatically and continuously ventilating the crankcase. The system includes an essentially atmospheric pressure fresh air inlet to the engine passing air through to the crankcase and a connection from the oil pan to the vacuum in the intake manifold establishing a constant flow of crankcase vapors. The oil pan has a baffle partitioning it into an inner oil collecting funnel-like crankcase cavity and an outer oil reservoir. The inner cavity has an opening at its lower-most point for communication of oil with the reservoir. The opening is of a controlled vertical height for creating a pressure differential across the baffle during operation of the engine. Means connects the inner cavity to the air inlet pressure side of the PCV System while connecting the reservoir to the vacuum side of the PCV system for establishing a constant pressure differential across the baffle sufficient to displace the oil against gravity and maintain the oil level in the crankcase during operation of the engine at the height of the opening in the baffle. Gravity causes the oil to seek a level higher than the opening upon shutdown of the engine and the consequential decay of vacuum in the intake manifold.

  15. Measurement of SRS reactor recirculation pump performance using pump motor power

    SciTech Connect

    Whitehouse, J.C.

    1994-03-01

    In order to accurately predict reactor hydraulic behavior during a hypothetical Loss-of-Coolant-Accident (LOCA) the performance of reactor coolant pumps under off-design conditions must be understood. The LOCA of primary interest for the Savannah River Site (SRS) production reactors involves the aspiration of air into the recirculated heavy water flow as reactor tank inventory is lost (system temperatures are too low to result in significant flashing of water coolant into steam). Entrained air causes degradation in the performance of the large recirculation pumps. The amount of degradation is a parameter used in computer codes which predict the course of the accident. This paper describes the analysis of data obtained during in-reactor simulated LOCA tests, and presents the head degradation curve for the SRS reactor recirculation pumps. The greatest challenge of the analysis was to determine a reasonable estimate of mixture density at the pump suction. Specially designed three-beam densitometers were used to determine mixture density. Since it was not feasible to place them in the most advantageous location the measured pump motor power, along with other techniques (pressure corrected gamma densitometer void fraction), were used to calculate the average mixture density at the pump impeller. These techniques provided good estimates of pump suction mixture density. Measurements from more conventional instruments were used to arrive at the value of pump two-component head over a wide range of flows. The results were significantly different from previous work with commercial reactor recirculation pumps.

  16. Aircraft Engine Sump Fire Mitigation, Phase 2

    NASA Technical Reports Server (NTRS)

    Rosenlieb, J. W.

    1978-01-01

    The effect of changes in the input parameters (air leakage flow rate and temperature and lubricating oil inlet flow rate and temperature) over a specified range on the flammability conditions within an aircraft engine bearing sump was investigated. An analytical study was performed to determine the effect of various parameters on the generation rate of oil vapor from oil droplets in a hot air stream flowing in a cylindrical tube. The ignition of the vapor-air mixture by an ignition source was considered. The experimental investigation demonstrated that fires would be ignited by a spark ignitor over the full range of air and oil flow rates and air temperatures evaluated. However, no fires could be ignited when the oil inlet temperature was maintained below 41.7 K (290 F). The severity of the fires ignited were found to be directly proportional to the hot air flow rate. Reasonably good correlation was found between the mixture temperature in the sump at the ignitor location and the flammability limits as defined by flammability theory; thus a fairly reliable experimental method of determining flammable conditions within a sump was demonstrated. The computerized mathematical model shows that oil droplet size and air temperature have the greatest influence on the generation rate of oil vapor.

  17. Performance of two-stage vegetable waste anaerobic digestion depending on varying recirculation rates.

    PubMed

    Zuo, Zhuang; Wu, Shubiao; Zhang, Wanqin; Dong, Renjie

    2014-06-01

    Vegetable waste, which characterized by high moisture content, was evaluated as a substrate for biogas production. The effects of recirculation rate (RR) on the performance of two-stage anaerobic digestion were investigated. The system was operated at an organic loading rate of 1.7 g VS/L/d with varying RRs (0, 0.6, 1, and 1.4). Results demonstrated that volumetric biogas production rates in acidogenic reactor increased from approximately 0.2 7 L/L/d to 0.97 L/L/d, when pH is increased from approximately 5.1 to 6.7. These indicate that recirculation of alkaline effluent from the methanogenic reactor helps create a favorable condition for biogas production in the acidogenic reactor. The decrease in chemical oxygen demand (COD) concentrations from approximately 21,000 mg/L to 6800 mg/L was also observed in the acidogenic reactor. This condition may be attributed to dilution under recirculation. The dynamics between hydrolysis and methanogenesis under recirculation indicated that mass transfer capacity between two-stage reactors improved. PMID:24759642

  18. Performance of Water Recirculation Loop Maintenance Components for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessons learned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  19. Performance of Water Recirculation Loop Maintentance Components for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

    Water loop maintenance components to maintain the water quality of the Advanced Spacesuit Water Membrane Evaporation (SWME) water recirculation loop have undergone a comparative performance evaluation with a second SWME water recirculation loop with no water quality maintenance. Results show the benefits of periodic water maintenance. The SWME is a heat rejection device under development at the NASA Johnson Space Center to perform thermal control for advanced spacesuits. One advantage to this technology is the potential for a significantly greater degree of tolerance to contamination when compared to the existing Sublimator technology. The driver for the evaluation of water recirculation maintenance components was to further enhance this advantage through the leveraging of fluid loop management lessonslearned from the International Space Station (ISS). A bed design that was developed for a UTAS military application, and considered for a potential ISS application with the Urine Processor Assembly, provided a low pressure drop means for water maintenance in a recirculation loop. The bed design is coupled with high capacity ion exchange resins, organic adsorbents, and a cyclic methodology developed for the Extravehicular Mobility Unit (EMU) Transport Water loop. The maintenance cycle included the use of a biocide delivery component developed for ISS to introduce a biocide in a microgravity-compatible manner for the Internal Active Thermal Control System (IATCS). The leveraging of these water maintenance technologies to the SWME recirculation loop is a unique demonstration of applying the valuable lessons learned on the ISS to the next generation of manned spaceflight Environmental Control and Life Support System (ECLSS) hardware.

  20. Air-Operated Sump Pump

    NASA Technical Reports Server (NTRS)

    Nolt, Gary D.

    1988-01-01

    Pump removes liquid seepage from small, restricted area and against large pressure head. Developed for moving small amounts of water and oil from sump pit 85 ft (25.91 m) deep. Fits in space only 6 1/2 in. (16.5 cm) in diameter and 18 in. (45.7 cm) long. In discharge part of pumping cycle, air forces liquid out of pump chamber through pipe. During filling part of pumping cycle, water enters pump chamber from sump pit. Float in chamber next to pump chamber controls pressurization through timer and solenoid valve.

  1. Anaerobic digestion of food waste - Effect of recirculation and temperature on performance and microbiology.

    PubMed

    Zamanzadeh, Mirzaman; Hagen, Live H; Svensson, Kine; Linjordet, Roar; Horn, Svein J

    2016-06-01

    Recirculation of digestate was investigated as a strategy to dilute the food waste before feeding to anaerobic digesters, and its effects on microbial community structure and performance were studied. Two anaerobic digesters with digestate recirculation were operated at 37 °C (MD + R) and 55 °C (TD + R) and compared to two additional digesters without digestate recirculation operated at the same temperatures (MD and TD). The MD + R digester demonstrated quite stable and similar performance to the MD digester in terms of the methane yield (around 480 mL CH4 per gVSadded). In both MD and MD + R Methanosaeta was the dominant archaea. However, the bacterial community structure was significantly different in the two digesters. Firmicutes dominated in the MD + R, while Chloroflexi was the dominant phylum in the MD. Regarding the thermophilic digesters, the TD + R showed the lowest methane yield (401 mL CH4 per gVSadded) and accumulation of VFAs. In contrast to the mesophilic digesters, the microbial communities in the thermophilic digesters were rather similar, consisting mainly of the phyla Firmicutes, Thermotoga, Synergistetes and the hydrogenotrophic methanogen Methanothermobacter. The impact of ammonia inhibition was different depending on the digesters configurations and operating temperatures. PMID:27060528

  2. Performance of an in-situ rotating biological contactor in a recirculating aquaculture system.

    PubMed

    Marin, P; Donoso-Bravo, A; Campos, J L; Ruiz-Filippi, G; Chamy, R

    2011-01-01

    The start-up and activation of a nitrifying rotating biological contactor (RBC) and its performance inside a culture tank of rainbow trout were studied. First, in a lab-scale operation, the system was fed with a synthetic medium containing a high ammonia concentration (567 mg NH(4)(+)-N L(-1)) and operated at a high hydraulic retention time (HRT) (6.5 days) to minimize the wash-out of the biomass and promote the biofilm formation. Then, both inlet ammonia concentration and HRT were decreased in order to obtain operational conditions similar to those of the culture tank. During this period, the RBC was able to treat an ammonia loading rate (ALR) of 0.64 g N-NH(4)(+) L(-1) d(-1) with a removal efficiency within 70-100%. Pilot-scale experiments were carried out in culture tanks of rainbow trout. The operation of a recirculating system with the RBC unit was compared with a recirculating system without biological treatment and with a flow-through system. The use of this in-situ nitrifying unit allowed working at a recirculation ratio of 90% without negative effects on either growth or the condition factor of fishes. Up to 70% of ammonia generated was removed and a removal rate of 1.41 g NH(4)(+)-N m(-2) d(-1) was reached. PMID:22156125

  3. Flue gas recirculation and enhanced performance of waste incinerators under waste uncertainty.

    PubMed

    Tsiliyannis, Christos Aristeides

    2013-07-16

    Variations in waste quantities and composition affect incinerator operating conditions and performance. Fluegas volumes consititute a dominant environmental and financial consideration for efficient waste incinerator (WI) operation, since they affect the temperature, throughput, air pollution control system (APCS) residence time, and pollutant emissions, when the charging rate or composition of any waste is varying. Fluegas recirculation (FGR) in WI is an effective technique for reducing WI atmospheric pollution, mainly NOx emissions, albeit affecting WI throughput, temperature and destruction/removal efficiency. FGR refers to mass recirculation of a possibly cooled fraction of fluegases and differs substantially from fluegas heat recovery. The present work shows that, besides emission control, suitable manipulation of FGR enhances WI performance under waste uncertainty, enabling higher throughput, at the desired temperature and within the allowed APCS residence time range. A dimensionless parameter related to the uncertain wastes' net enthalpy contribution is isolated, which encompasses heat of reaction and enthalpy outflows from fluegas and solids and which reveals whether throughput is decreasing or increasing with temperature and FGR ratio. Normalized throughput and total fluegas volume isotherms manifest the interdependence and enable manipulation for enhanced environmental and economic performance. PMID:23781842

  4. DWPF DECON FRIT: SUMP AND SLURRY SOLIDS ANALYSIS

    SciTech Connect

    Crawford, C.; Peeler, D.; Click, D.

    2010-10-20

    The Savannah River National Laboratory (SRNL) has been requested to perform analyses on samples of the Defense Waste Processing Facility (DWPF) decon frit slurry (i.e., supernate samples and sump solid samples). Four 1-L liquid slurry samples were provided to SRNL by Savannah River Remediation (SRR) from the 'front-end' decon activities. Additionally, two 1-L sump solids samples were provided to SRNL for compositional and physical analysis. In this report, the physical and chemical characterization results of the slurry solids and sump solids are reported. Crawford et al. (2010) provide the results of the supernate analysis. The results of the sump solids are reported on a mass basis given the samples were essentially dry upon receipt. The results of the slurry solids were converted to a volume basis given approximately 2.4 grams of slurry solids were obtained from the {approx}4 liters of liquid slurry sample. Although there were slight differences in the analytical results between the sump solids and slurry solids the following general summary statements can be made. Slight differences in the results are also captured for specific analysis. (1) Physical characterization - (a) SEM/EDS analysis suggested that the samples were enriched in Li and Si (B and Na not detectable using the current EDS system) which is consistent with two of the four principle oxides of Frit 418 (B{sub 2}O{sub 3}, Na{sub 2}O, Li{sub 2}O and SiO{sub 2}). (b) SEM/EDS analysis also identified impurities which were elementally consistent with stainless steel (i.e., Fe, Ni, Cr contamination). (c) XRD results indicated that the sump solids samples were amorphous which is consistent with XRD results expected for a Frit 418 based sample. (d) For the sump solids, SEM/EDS analysis indicated that the particle size of the sump solids were consistent with that of an as received Frit 418 sample from a current DWPF vendor. (e) For the slurry solids, SEM/EDS analysis indicated that the particle size range

  5. Study of performances, stability and microbial characterization of a Sequencing Batch Biofilter Granular Reactor working at low recirculation flow.

    PubMed

    De Sanctis, Marco; Beccari, Mario; Di Iaconi, Claudio; Majone, Mauro; Rossetti, Simona; Tandoi, Valter

    2013-02-01

    The Sequencing Batch Biofilter Granular Reactor (SBBGR) is a promising wastewater treatment technology characterized by high biomass concentration in the system, good depuration performance and low sludge production. Its main drawback is the high energy consumption required for wastewater recirculation through the reactor bed to ensure both shear stress and oxygen supply. Therefore, the effect of low recirculation flow on the long-term (38 months) performance of a laboratory scale SBBGR was studied. Both the microbial components of the granules, and their main metabolic activities were evaluated (heterotrophic oxidation, nitrification, denitrification, fermentation, sulphate reduction and methanogenesis). The results indicate that despite reduced recirculation, the SBBGR system maintained many of its advantageous characteristics. PMID:23313178

  6. Anode gas recirculation for improving the performance and cost of a 5-kW solid oxide fuel cell system

    NASA Astrophysics Data System (ADS)

    Torii, Ryohei; Tachikawa, Yuya; Sasaki, Kazunari; Ito, Kohei

    2016-09-01

    Solid oxide fuel cells (SOFCs) have the potential to efficiently convert chemical energy into electricity and heat and are expected to be implemented in stationary combined heat and power (CHP) systems. This paper presents the heat balance analysis for a 5-kW medium-sized integrated SOFC system and the evaluation of the effect of anode gas recirculation on the system performance. The risk of carbon deposition on an SOFC anode due to anode gas recirculation is also assessed using the C-H-O diagram obtained from thermodynamic equilibrium calculations. These results suggest that a higher recirculation ratio increases net fuel utilization and improves the electrical efficiency of the SOFC system. Furthermore, cost simulation of the SOFC system and comparison with the cost of electricity supply by a power grid indicates that the capital cost is sufficiently low to popularize the SOFC system in terms of the total cost over one decade.

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  8. Effects of organic loading rate and effluent recirculation on the performance of two-stage anaerobic digestion of vegetable waste.

    PubMed

    Zuo, Zhuang; Wu, Shubiao; Zhang, Wanqin; Dong, Renjie

    2013-10-01

    The effects of organic loading rates (OLR) and effluent recirculation on dynamics of acidogenic and methanogenic processes in two-stage anaerobic digestion of vegetable waste were investigated. Two systems were performed at OLRs of 1.3, 1.7, 2.1 and 2.6 g VS/L/d. One system recirculated the effluent from the methanogenic reactor to acidogenic reactor. With increasing OLRs, total volatile fatty acid (VFA) concentration increased to approximately 8500 mg/L in acidogenic digester, where pH decreased from 6.4 to 5.2. Daily biogas production and methane content in methanogenic reactor increased from 1.2 to 4.4 L/d and from 27.4% to 60.5%, respectively. However, inhibition of hydrolysis in acidogenic reactor was demonstrated under the OLR of 2.6 g VS/L/d without recirculation, thus indicating system overloading. Effluent recirculation shown a considerable positive effect on alleviating VFA inhibition and improving biogas production in acidogenic reactor because of the effect of dilution and pH adjustment, particularly at high OLRs. PMID:23973975

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  10. Improvement of anaerobic digester performance by wastewater recirculation through an aerated membrane.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Swine wastewater from an anaerobic digester was recirculated through a silicone hose located in an external aeration chamber to determine its effect on wastewater malodorants and biogas composition. The silicone hose acted as a semipermeable membrane for the passage of small molecules. In the first...

  11. 14 CFR 25.971 - Fuel tank sump.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... must have a sump with an effective capacity, in the normal ground attitude, of not less than the... with the airplane in the ground attitude. (c) Each fuel tank sump must have an accessible drain...

  12. 14 CFR 29.971 - Fuel tank sump.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... effective with the rotorcraft in any normal attitude, and must be located so that the sump contents cannot... water from each part of the tank to the sump with the rotorcraft in any ground attitude to be...

  13. Effect of self recirculation casing treatment on the performance of a turbocharger centrifugal compressor

    NASA Astrophysics Data System (ADS)

    Gancedo, Matthieu

    Increase in emission regulations in the transport industry brings the need to have more efficient engines. A path followed by the automobile industry is to downsize the size of the internal combustion engine and increase the air density at the intake to keep the engine power when needed. Typically a centrifugal compressor is used to force the air into the engine, it can be powered from the engine shaft (superchargers) or extracting energy contained into the hot exhaust gases with a turbine (turbochargers). The flow range of the compressor needs to match the one of the engine. However compressors mass flow operating range is limited by choke on the high end and surge on the low end. In order to extend the operation at low mass flow rates, the use of passive devices for turbocharger centrifugal compressors was explored since the late 80's. Hence, casing treatments including flow recirculation from the inducer part of the compressor have been shown to move the surge limit to lower flows. Yet, the working mechanisms are still not well understood and thus, to optimize the design of this by-pass system, it is necessary to determine the nature of the changes induced by the device both on the dynamic stability of the pressure delivery and on the flow at the inlet. The compressor studied here features a self-recirculating casing treatment at the inlet. The recirculation passage could be blocked to carry a direct comparison between the cases with and without the flow feature. To grasp the effect on compressor stability, pressure measurements were taken in the different constituting elements of the compressor. The study of the mean pressure variations across the operating map showed that the tongue region is a limiting element. Dynamic pressure measurements revealed that the instabilities generated near the inducer when the recirculation is blocked increase the overall instability levels at the compressor outlet and propagating pressure waves starting at the tongue occurred

  14. 14 CFR 23.971 - Fuel tank sump.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel tank sump. 23.971 Section 23.971... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Fuel System § 23.971 Fuel tank sump. (a) Each fuel tank must have a drainable sump with an effective capacity, in the...

  15. 14 CFR 23.971 - Fuel tank sump.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank sump. 23.971 Section 23.971... STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Powerplant Fuel System § 23.971 Fuel tank sump. (a) Each fuel tank must have a drainable sump with an effective capacity, in the...

  16. 14 CFR 25.971 - Fuel tank sump.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... fuel tank must allow drainage of any hazardous quantity of water from any part of the tank to its sump... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank sump. 25.971 Section 25.971... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.971 Fuel tank sump. (a) Each fuel...

  17. 14 CFR 25.971 - Fuel tank sump.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... fuel tank must allow drainage of any hazardous quantity of water from any part of the tank to its sump... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel tank sump. 25.971 Section 25.971... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.971 Fuel tank sump. (a) Each fuel...

  18. Sump bay fever: inhalational fever associated with a biologically contaminated water aerosol.

    PubMed Central

    Anderson, K; McSharry, C P; Clark, C; Clark, C J; Barclay, G R; Morris, G P

    1996-01-01

    OBJECTIVE: To investigate the clinical, serological, and environmental features of a work related inhalational fever associated with exposure to an aerosol generated from a biologically contaminated 130,000 gallon water pool in a building used for testing scientific equipment. METHOD: Cross sectional survey of all exposed subjects (n = 83) by symptom questionnaire, clinical examination, spirometry, and serology for antibody to Pseudomonads, pool water extract, and endotoxin. In symptomatic patients diffusion capacity was measured, and chest radiology was performed if this was abnormal. Serial peak flow was recorded in those subjects with wheeze. Bacterial and fungal air sampling was performed before and during operation of the water pool pump mechanism. Endotoxin was measured in the trapped waters and in the pumps. Serum cotinine was measured as an objective indicator of smoking. RESULTS: Of the 20 symptomatic subjects, fever was most common in those with the highest exposure (chi 2 42.7, P < 0.001) in the sump bay when the water was (torrentially) recirculated by the water pumps. Symptoms occurred late in the working day only on days when the water pumps were used, and were independent of the serum cotinine. Pulmonary function was normal in most subjects (spirometry was normal in 79/83, diffusion capacity was low in five subjects, chest radiology was normal). Peak flow recording did not suggest a work relation. The bacterial content of the aerosol rose from 6 to > 10,000 colony forming units per cubic metre (cfu/m3) (predominantly environmental Pseudomonads) when the pumps were operating. High endotoxin concentrations were measured in the waters and oil sumps in the pumps. Low concentrations of antibody to the organisms isolated were detected (apart from two subjects with high antibody) but there was no relation to exposure or the presence of symptoms and similar antibody was found in the serum samples from a non-exposed population. The fever symptoms settled

  19. Effect of stocking density on performances of juvenile turbot ( Scophthalmus maximus) in recirculating aquaculture systems

    NASA Astrophysics Data System (ADS)

    Li, Xian; Liu, Ying; Blancheton, Jean-Paul

    2013-05-01

    Limited information has been available about the influence of loading density on the performances of Scophthalmus maximus, especially in recirculating aquaculture systems (RAS). In this study, turbot (13.84±2.74 g; average weight±SD) were reared at four different initial densities (low 0.66, medium 1.26, sub-high 2.56, high 4.00 kg/m2) for 10 weeks in RAS at 23±1°C. Final densities were 4.67, 7.25, 14.16, and 17.47 kg/m2, respectively, which translate to 82, 108, 214, and 282 percent coverage of the tank bottom. Density had both negative and independent impacts on growth. The final mean weight, specific growth rate (SGR), and voluntary feed intake significantly decreased and the coefficient of variation (CV) of final body weight increased with increase in stocking density. The medium and sub-high density groups did not differ significantly in SGR, mean weight, CV, food conversion rate (FCR), feed intake, blood parameters, and digestive enzymes. The protease activities of the digestive tract at pH 7, 8.5, 9, and 10 were significantly higher for the highest density group, but tended to be lower (not significantly) at pH 4 and 8.5 for the lowest density group. The intensity of protease activity was inversely related to feed intake at the different densities. Catalase activity was higher (but not significantly) at the highest density, perhaps because high density started to induce an oxidative effect in turbot. In conclusion, turbot can be cultured in RAS at a density of less than 17.47 kg/m2. With good water quality and no feed limitation, initial density between 1.26 and 2.56 kg/m2 (final: 7.25 and 14.16 kg/m2) would not negatively affect the turbot cultured in RAS. For culture at higher density, multi-level feeding devices are suggested to ease feeding competition.

  20. Influence of alkalinity and VFAs on the performance of an UASB reactor with recirculation for the treatment of Tequila vinasses.

    PubMed

    López-López, Alberto; León-Becerril, Elizabeth; Rosales-Contreras, María Elena; Villegas-García, Edgardo

    2015-01-01

    The main problem linked to the stability of upflow anaerobic sludge blanket (UASB) reactors during the treatment of Tequila vinasse is the high acidity and the null alkalinity present in this effluent. This research evaluates the effect of alkalinity and volatile fatty acids (VFAs) concentration on the performance of an UASB reactor with recirculation of the effluent for removing organic matter and biogas production from Tequila vinasses. Recirculation of the effluent reduces the impact of VFAs and organic matter concentration present in the influent, inducing the stability of the reactor. The UASB reactor was operated during 235 days at organic loading rates from 2.5 to 20.0 kg m(-3) d(-1), attaining a removal efficiency of COD greater than 75% with a methane yield of 335 ml CH4 g(-1) COD at SPT, maintaining a ratio of VFAs/Alk ≤ 0.5. Therefore, an optimal ratio of VFAs/Alk was established for the system operating in stable conditions for the treatment of Tequila vinasses. Under these conditions, the alkalinity was recuperated by the system itself, without the addition of external alkalinity. PMID:25827467

  1. The effects of ozone and water exchange rates on water quality and rainbow trout Oncorhynchus mykiss performance in replicated water recirculating systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rainbow trout Oncorhynchus mykiss performance and water quality were evaluated and compared within six replicated 9.5 cubic meter water recirculating aquaculture systems (WRAS) operated with and without ozone at various water exchange rates. Three separate studies were conducted: 1) low water exchan...

  2. 14 CFR 23.971 - Fuel tank sump.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... system must have a sediment bowl or chamber that is accessible for drainage; has a capacity of 1 ounce... normal flight attitude, water will drain from all parts of the tank except the sump to the sediment bowl or chamber. (d) Each sump, sediment bowl, and sediment chamber drain required by paragraphs (a),...

  3. 14 CFR 23.971 - Fuel tank sump.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... system must have a sediment bowl or chamber that is accessible for drainage; has a capacity of 1 ounce... normal flight attitude, water will drain from all parts of the tank except the sump to the sediment bowl or chamber. (d) Each sump, sediment bowl, and sediment chamber drain required by paragraphs (a),...

  4. 40 CFR 61.133 - Standard: Light-oil sumps.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... detectable emissions, using Method 21 (40 CFR part 60, appendix A) and the procedures specified in § 61.245(c... 40 Protection of Environment 9 2012-07-01 2012-07-01 false Standard: Light-oil sumps. 61.133... Emissions from Coke By-Product Recovery Plants § 61.133 Standard: Light-oil sumps. (a) Each owner...

  5. 40 CFR 61.133 - Standard: Light-oil sumps.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... detectable emissions, using Method 21 (40 CFR part 60, appendix A) and the procedures specified in § 61.245(c... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Standard: Light-oil sumps. 61.133... Emissions from Coke By-Product Recovery Plants § 61.133 Standard: Light-oil sumps. (a) Each owner...

  6. 40 CFR 61.133 - Standard: Light-oil sumps.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... detectable emissions, using Method 21 (40 CFR part 60, appendix A) and the procedures specified in § 61.245(c... 40 Protection of Environment 9 2013-07-01 2013-07-01 false Standard: Light-oil sumps. 61.133... Emissions from Coke By-Product Recovery Plants § 61.133 Standard: Light-oil sumps. (a) Each owner...

  7. 14 CFR 25.971 - Fuel tank sump.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank sump. 25.971 Section 25.971... STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System § 25.971 Fuel tank sump. (a) Each fuel tank... fuel tank must allow drainage of any hazardous quantity of water from any part of the tank to its...

  8. 14 CFR 27.971 - Fuel tank sump.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank sump. 27.971 Section 27.971... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Fuel System § 27.971 Fuel tank sump. (a) Each fuel tank... of 0.25 percent of the tank capacity or 1/16 gallon, whichever is greater, unless— (1) The...

  9. 14 CFR 23.971 - Fuel tank sump.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... system must have a sediment bowl or chamber that is accessible for drainage; has a capacity of 1 ounce... normal flight attitude, water will drain from all parts of the tank except the sump to the sediment bowl or chamber. (d) Each sump, sediment bowl, and sediment chamber drain required by paragraphs (a),...

  10. 14 CFR 29.971 - Fuel tank sump.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel tank sump. 29.971 Section 29.971... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.971 Fuel tank sump. (a) Each fuel tank... escape through the tank outlet opening. (c) Each fuel tank must allow drainage of hazardous quantities...

  11. 14 CFR 29.971 - Fuel tank sump.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank sump. 29.971 Section 29.971... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.971 Fuel tank sump. (a) Each fuel tank... escape through the tank outlet opening. (c) Each fuel tank must allow drainage of hazardous quantities...

  12. 14 CFR 29.971 - Fuel tank sump.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank sump. 29.971 Section 29.971... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System § 29.971 Fuel tank sump. (a) Each fuel tank... escape through the tank outlet opening. (c) Each fuel tank must allow drainage of hazardous quantities...

  13. The eddy-eliminating method of guide cone in the closed sump

    NASA Astrophysics Data System (ADS)

    Wang, Y. J.; Cheng, L.; Xia, C. Z.; Zhou, J. R.; Yan, H. Q.; Jiang, H. Y.

    2016-05-01

    In order to explore the effect on eddy-eliminating method of guide cone in the closed sump, the simple factor analysis and CFD numerical simulation are applied to calculate the flow field of closed sump and select ω-shaped back wall. ω-shaped back wall is consistent with the stream line in the suction sump, on this basis, CFD numerical simulation is conducted with the eddy-eliminating of the triangle guide cone and traditional guide cone. The results show that, for eddy-eliminating measures, with the height of triangular guide cone from 0 to 0.407HZ/DL , the excessive triangle guide cone hinder water into the flared pipe. With the width of triangular guide cone from 0.5 to 1.0BZ/DL , increasing width of triangular guide cone may increase the pumping hydraulic performance and pumping efficiency. However with the width of triangular guide cone from 0.5 to 1.0 BZ/DL , too broad traditional guide cone hinder water into the flared pipe. In the design discharge, whether triangle guide cone or traditional guide cone have a little effect on the efficiency of the pumping station. But in terms of the eddy-eliminating on the bottom of suction sump, it is necessary to set up guide cone.

  14. Investigations on sump cooling after core melt down

    SciTech Connect

    Knebel, J.U.

    1995-09-01

    This article presents the basic physical phenomena and scaling criteria of decay heat removal from a large coolant pool by single-phase and two-phase natural circulation flow. The physical significance of the dimensionless similarity groups derived is evaluated. The above results are applied to the SUCO program that is performed at the Forschungszentrum Karlsruhe. The SUCO program is a three-step series of scaled model experiments investigating the possibility of an optional sump cooling concept for the European Pressurized Water Reactor EPR. This concept is entirely based on passive safety features within the containment. The work is supported by the German utilities and the Siemens dimensional SUCOS-2D test facility. The experimental results of the model geometry are transformed to prototypic conditions.

  15. AREVA Team Develops Sump Strainer Blockage Solution for PWRs

    SciTech Connect

    Phan, Ray

    2006-07-01

    The purpose of this paper is to discuss the methodology, testing challenges, and results of testing that a team of experts from Areva NP, Alden Research Laboratory, Inc (ALDEN), and Performance Contracting Inc. (PCI) has developed. The team is currently implementing a comprehensive solution to the issue of Emergency Core Cooling System (ECCS) sump strainer blockage facing Pressurized Water Reactor (PWR) Nuclear Plants. The team has successfully demonstrated two key results from the testing of passive Sure-FlowTM strainers, which were designed to distribute the required flow over a large surface area resulting in extremely low approach velocities. First, the actual head loss (pressure drop) as tested, across the prototype strainers, was much lower than the calculated head loss using the Nuclear Regulatory Commission (NRC) approved NUREG/CR-6224 head loss correlation. Second, the penetration fractions were much lower than those seen in the NRC sponsored debris penetration tests. (author)

  16. Design and performance characteristics of a low-head recirculating aquaculture tank system for low salinity finfish production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water treatment components of a recirculating aquaculture system (RAS) consist mainly of: solid removal devices, biofiltration, aeration, degassing units, and water distribution. For each component, multiple options are available and the selection is based on system volume, system hydrodynamics, fis...

  17. The effects of different seeding ratios on nitrification performance and biofilm formation in marine recirculating aquaculture system biofilter.

    PubMed

    Zhu, Songming; Shen, Jiazheng; Ruan, Yunjie; Guo, Xishan; Ye, Zhangying; Deng, Yale; Shi, Mingming

    2016-07-01

    Rapid start-up of biofilter is essential for intensive marine recirculating aquaculture system (RAS) production. This study evaluated the nitrifying biofilm formation using mature biofilm as an inoculum to accelerate the process in RAS practice. The effects of inoculation ratios (0-15 %) on the reactor performance and biofilm structure were investigated. Complete nitrification was achieved rapidly in reactors with inoculated mature biofilm (even in 32 days when 15 % seeding ratio was applied). However, the growth of target biofilm on blank carrier was affected by the mature biofilm inoculated through substrate competition. The analysis of extracellular polymeric substance (EPS) and nitrification rates confirmed the divergence of biofilm cultivation among reactors. Besides, three N-acyl-homoserine lactones (AHLs) were found in the process, which might regulate the activities of biofilm. Multivariate analysis based on non-metric multidimensional scaling (nMDS) also indicated the great roles of AHLs and substrate supply which might fundamentally determine varied cultivation performance on target biofilm. PMID:27068911

  18. A simple high-performance matrix-free biomass molten carbonate fuel cell without CO2 recirculation

    PubMed Central

    Lan, Rong; Tao, Shanwen

    2016-01-01

    In previous reports, flowing CO2 at the cathode is essential for either conventional molten carbonate fuel cells (MCFCs) based on molten carbonate/LiAlO2 electrolytes or matrix-free MCFCs. For the first time, we demonstrate a high-performance matrix-free MCFC without CO2 recirculation. At 800°C, power densities of 430 and 410 mW/cm2 are achieved when biomass—bamboo charcoal and wood, respectively–is used as fuel. At 600°C, a stable performance is observed during the measured 90 hours after the initial degradation. In this MCFC, CO2 is produced at the anode when carbon-containing fuels are used. The produced CO2 then dissolves and diffuses to the cathode to react with oxygen in open air, forming the required CO32− or CO42− ions for continuous operation. The dissolved O2− ions may also take part in the cell reactions. This provides a simple new fuel cell technology to directly convert carbon-containing fuels such as carbon and biomass into electricity with high efficiency. PMID:27540588

  19. A simple high-performance matrix-free biomass molten carbonate fuel cell without CO2 recirculation.

    PubMed

    Lan, Rong; Tao, Shanwen

    2016-08-01

    In previous reports, flowing CO2 at the cathode is essential for either conventional molten carbonate fuel cells (MCFCs) based on molten carbonate/LiAlO2 electrolytes or matrix-free MCFCs. For the first time, we demonstrate a high-performance matrix-free MCFC without CO2 recirculation. At 800°C, power densities of 430 and 410 mW/cm(2) are achieved when biomass-bamboo charcoal and wood, respectively-is used as fuel. At 600°C, a stable performance is observed during the measured 90 hours after the initial degradation. In this MCFC, CO2 is produced at the anode when carbon-containing fuels are used. The produced CO2 then dissolves and diffuses to the cathode to react with oxygen in open air, forming the required [Formula: see text] or [Formula: see text] ions for continuous operation. The dissolved [Formula: see text] ions may also take part in the cell reactions. This provides a simple new fuel cell technology to directly convert carbon-containing fuels such as carbon and biomass into electricity with high efficiency. PMID:27540588

  20. 14 CFR 27.971 - Fuel tank sump.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... system has a sediment bowl or chamber that is accessible for preflight drainage and has a minimum... the sediment bowl or chamber. (b) Each sump, sediment bowl, and sediment chamber drain required...

  1. 14 CFR 27.971 - Fuel tank sump.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... system has a sediment bowl or chamber that is accessible for preflight drainage and has a minimum... the sediment bowl or chamber. (b) Each sump, sediment bowl, and sediment chamber drain required...

  2. 14 CFR 27.971 - Fuel tank sump.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... system has a sediment bowl or chamber that is accessible for preflight drainage and has a minimum... the sediment bowl or chamber. (b) Each sump, sediment bowl, and sediment chamber drain required...

  3. 14 CFR 27.971 - Fuel tank sump.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... system has a sediment bowl or chamber that is accessible for preflight drainage and has a minimum... the sediment bowl or chamber. (b) Each sump, sediment bowl, and sediment chamber drain required...

  4. Final report for Tank 100 Sump sludge (KON332) for polychlorinated biphenyl`s (PCB)

    SciTech Connect

    Fuller, R.K.

    1998-07-30

    Final Report for Tank 100 Sump Sludge (KON332) for Polychlorinated Biphenyl`s (PCB) Sample Receipt Sample KON332 was received from Tank 100-Sump (WESF) on May 18, 1998. The laboratory number issued for this sample is S98BOO0207 as shown on the Request for Sample Analysis (RSA) form (Attachment 4). The sample breakdown diagram (Attachment 3) provides a cross-reference of customer sample identification to the laboratory identification number. Attachment 4 provides copies of the Request for Sample Analysis (RSA) and Chain of Custody (COC) forms. The sample was received in the laboratory in a 125-ml polybottle. Breakdown and subsampling was performed on June 6, 1998. PCB analysis was performed on the wet sludge. A discussion of the results is presented in Attachment 2. The 222-S extraction bench sheets are presented in Attachment 5. The PCB raw data are presented in Attachment 6.

  5. The impact of water exchange rate on the health and performance of rainbow trout Oncorhynchus mykiss in recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fish mortality in recirculating aquaculture systems (RAS) has been observed by the authors to increase when RAS are managed at low makeup water exchange rates with relatively high feed loading. The precise etiology of this elevated mortality was unknown, all typical water quality parameters were wit...

  6. The effects of carbon dioxide on performance and histopathology of rainbow trout Oncorhynchus mykiss in water recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Chronic exposure to elevated levels of dissolved carbon dioxide (CO2) has been linked to reduced growth, physiological disturbances and negative health outcomes in intensively reared fish. Although pumping to a degassing tower can lower concentrations of dissolved CO2 in water recirculation aquacult...

  7. Beam breakup in superconducting recirculating linacs

    SciTech Connect

    Joseph J. Bisognano

    1988-05-01

    The performance and operational flexibility of superconducting recirculating linacs can be limited by a variety of collective phenomena which are grouped under the name beam breakup. In this note the various beam breakup phenomena found in recirculating superconducting radio frequency linacs are described and appraised relative to beam performance.

  8. Dynamic effect of leachate recirculation on batch mode solid state anaerobic digestion: Influence of recirculated volume, leachate to substrate ratio and recirculation periodicity.

    PubMed

    Degueurce, Axelle; Trémier, Anne; Peu, Pascal

    2016-09-01

    Performances of batch mode solid state anaerobic digestion (SSAD) were investigated through several leachate recirculation strategies. Three parameters were shown to particularly influence methane production rates (MPR) and methane yields: the length of the interval between two recirculation events, the leachate to substrate (L:S) ratio and the volume of leachate recirculated. A central composite factor design was used to determine the influence of each parameter on methane production. Results showed that lengthening the interval between two recirculation events reduced methane yield. This effect can be counteracted by recirculating a large volume of leachate at a low L:S ratio. Steady methane production can be obtained by recirculating small amounts of leachate, and by lengthening the interval between two recirculations, regardless of the L:S ratio. However, several combinations of these parameters led to similar performances meaning that leachate recirculation practices can be modified as required by the specific constraints SSAD plants configurations. PMID:27281433

  9. Liability issues surrounding oil drilling mud sumps

    SciTech Connect

    Dillon, J.J.

    1994-04-01

    This presentation examines liability issues surrounding oil drilling mud sumps and discusses them in relation to two recent cases that arose in Ventura County, California. Following a brief history of regulatory interest in oil drilling mud and its common hazardous substances, various cause of action arising from oil drilling mud deposits are enumerated, followed by defenses to these causes of action. Section 8002 (m) of the Resource Conservation and Recovery Act is mentioned, as are constituents of oil and gas waste not inherent in petroleum and therefore not exempt from regulation under the petroleum exclusion in the Comprehensive Environmental Response, Compensation and Recovery Act. Key legal words such as hazardous substance, release, public and private nuisance, trespass, responsible parties, joint and several liability, negligence, and strict liability are explained. The effects on liability of knowledge of the deposits, duty to restore land to its original condition, consent to the deposit of oil drilling mud, and noncompliance and compliance with permit conditions are analyzed. The state-of-the-art defense and research to establish this defense are mentioned. The newly created cause of action for fear of increased risk of cancer is discussed. Issues on transfer of property where oil drilling mud has been deposited are explored, such as knowledge of prior owners being imputed to later owners, claims of fraudulent concealment, and as is' clauses. The effects on the oil and gas industry of the California Court of Appeals for the Second District rulings in Dolan v. Humacid-MacLeod and Stevens v. McQueen are speculated.

  10. Performance of a constructed wetland in treating brackish wastewater from commercial recirculating and super-intensive shrimp growout systems.

    PubMed

    Shi, Yonghai; Zhang, Genyu; Liu, Jianzhong; Zhu, Yazhu; Xu, Jiabo

    2011-10-01

    A recirculating aquaculture system was developed for treating Pacific white shrimp (Litopenaeus vannamei) production wastewater using an integrated vertical-flow (IVF) and five connected integrated horizontal flow (IHF) constructed wetlands as water treatment filters for mesohaline conditions (8.25‰-8.26‰ salinity). The constructed wetlands demonstrated the ability to reduce total nitrogen, total ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total phosphorous, chemical oxygen demand, and total suspended solids to levels significantly lower than those in effluents from culture tanks. Various water quality parameters in the culture tanks were deemed suitable for shrimp culture. The actual ratio of wetland area (A(w)) to culture tank area (A(t)) was 1.1439, and the estimated optimal ratio A(w)/A(t) was approximately 1. The IVF-IHF wetlands showed flexibility and reliability in consistently removing the main pollutants from commercial recirculating and super-intensive shrimp growout systems throughout the culture period. PMID:21852127

  11. Numerical simulation on geometrical parameters for closed sump

    NASA Astrophysics Data System (ADS)

    Wang, Y. X.; Cheng, L.; Xia, C. Z.; Zhou, J. R.; Yan, H. Q.; Jiang, H. Y.

    2016-05-01

    The closed sump is a typical inlet passage of middle and small pumping station. It has the characteristics of low channel height, small foundation excavation depth, simple structure, a single cross sectional shape changes, ease of construction and other features, so more and more attention and application has been paying on this closed sump in pumping station project. However the flowing pattern within the closed sump is complex, the design is not perfect in some respects, the structure size does not be optimized. Based on the background for renewal and transformation of a pumping station, according to the three-dimensional incompressible fluid Reynolds-averaged N-S equations, the RNG k-e model, the CFD technology. The study on the draught in closed sump might reduce the length of pump shaft to enhance the stability of the pump unit operation. The results reveal the effect of the change of the height of plate. The turbulence in back wall might cause vortex when the height is high. The height of plate had be recommended control in 0.65D-0.85D.The better parameter combination of geometry of closed sump had be given through comparing the results of the orthogonal test and the comprehensive test. The floor clearance should be control in 1.0D. (D is the diameter of flared pipe)

  12. 20. Station Unwatering Pumps and Sump Pump, view to the ...

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

    20. Station Unwatering Pumps and Sump Pump, view to the north. The station unwatering pumps are the two large units in the center and right foreground of photograph and are marked with the numbers 1 and 2. The sump pump is the smaller unit in left foreground of photograph. These pumps are used for unwatering the draft chests for maintenance. Note the draft tube unwatering valve visible in background between the two unwatering pumps. - Washington Water Power Clark Fork River Noxon Rapids Hydroelectric Development, Powerhouse, South bank of Clark Fork River at Noxon Rapids, Noxon, Sanders County, MT

  13. 5. Station Unwatering Pumps and Sump Pump for Units 1 ...

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

    5. Station Unwatering Pumps and Sump Pump for Units 1 and 2, view to the west. The unwatering pumps are the two larger items toward the right side of the photograph (one in foreground and one in background. The smaller item toward the left of the photograph is the sump pump. These pumps are used for draining water from the draft chest for maintenance. - Washington Water Power Clark Fork River Cabinet Gorge Hydroelectric Development, Powerhouse, North Bank of Clark Fork River at Cabinet Gorge, Cabinet, Bonner County, ID

  14. Experimental and CFD analysis for prediction of vortex and swirl angle in the pump sump station model

    NASA Astrophysics Data System (ADS)

    Kim, C. G.; Kim, B. H.; Bang, B. H.; Lee, Y. H.

    2015-01-01

    Sump model testing is mainly used to check flow conditions around the intake structure. In present paper, numerical simulation with SST turbulence model for a scaled sump model was carried out with air entrainment and two phases for prediction of locations of vortex generation. The sump model used for the CFD and experimental analysis was scaled down by a ratio of 1:10. The experiment was performed in Korea Maritime and Ocean University (KMOU) and the flow conditions around pump's intake structure were investigated. In this study, uniformity of flow distribution in the pump intake channel was examined to find out the specific causes of vortex occurrence. Furthermore, the effectiveness of an Anti Vortex Device (AVD) to suppress the vortex occurrence in a single intake pump sump model was examined. CFD and experimental analysis carried out with and without AVDs produced very similar results. Without the AVDs, the maximum swirl angle obtained for experimental and CFD analysis were 10.9 and 11.3 degree respectively. Similarly, with AVDs, the maximum swirl angle obtained for experimental and CFD analysis was 2.7 and 0.2 degree respectively. So, with reference to the ANSI/HI 98 standard that permits a maximum swirl angle of 5 degree, the use of AVDs in experimental and CFD analysis produced very desirable results which is well within the limit.

  15. 40 CFR 61.133 - Standard: Light-oil sumps.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... detectable emissions, using Method 21 (40 CFR part 60, appendix A) and the procedures specified in § 61.245(c... Emissions from Coke By-Product Recovery Plants § 61.133 Standard: Light-oil sumps. (a) Each owner...

  16. Relationship between Ethanol in Fuel and Corrosion in STP Sumps

    EPA Science Inventory

    Steve Pollock is a Compliance Inspector with the Petroleum Program in the Virginia Department of Environmental Quality. During his inspections of the STP sumps of underground storage tanks at gasoline service stations in Virginia, Mr. Pollock noticed odd corrosion reactions in so...

  17. TANK MIXING STUDY WITH FLOW RECIRCULATION

    SciTech Connect

    Lee, S.

    2014-06-25

    The primary objective of this work is to quantify the mixing time when two miscible fluids are mixed by one recirculation pump and to evaluate adequacy of 2.5 hours of pump recirculation to be considered well mixed in SRS tanks, JT-71/72. The work scope described here consists of two modeling analyses. They are the steady state flow pattern analysis during pump recirculation operation of the tank liquid and transient species transport calculations based on the initial steady state flow patterns. The modeling calculations for the mixing time are performed by using the 99% homogeneity criterion for the entire domain of the tank contents.

  18. Comparing the effects of feeding a grain- or a fish meal-based diet on water quality, waste production, and rainbow trout Oncorhynchus mykiss performance within low exchange water recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Feeding a fish meal-free grain-based diet (GB) was compared to feeding a fish meal-based diet (FM) relative to water quality criteria, waste production, water treatment process performance, and rainbow trout Oncorhynchus mykiss performance within six replicated water recirculating aquaculture system...

  19. Performance analysis on quality of optical frequency comb generated by the recirculating frequency shifter based on linear IQ modulator

    NASA Astrophysics Data System (ADS)

    Sun, Lu; Li, Jianping; Lin, Jiachuan; Xi, Lixia; Tang, Xianfeng; Zhang, Xiaoguang

    2015-11-01

    An optical frequency comb generator using a modified single-sideband recirculating frequency shifter scheme adopting a linear IQ modulator as the kernel device (SSB-RFS-LIQM) is proposed. The optical comb lines generated by the proposed scheme possess good features such as extreme flatness and high optical signal-to-noise ratio (OSNR), compared to the quality we can obtain when we use a conventional IQ modulator in the SSB-RFS structure (called SSB-RFS-CIQM scheme). The mechanism of how the SSB-RFS-LIQM works is carefully analyzed with analytical and numerical methods. With the capability of strong suppression of high-order crosstalk and less demand of the gain of erbium-doped fiber amplifiers (and hence less amplified spontaneous noise induced) in the loop, 5.5 dB OSNR improvement can be achieved when 100 extreme flat comb lines are generated using the SSB-RFS-LIQM scheme compared to using the SSB-RFS-CIQM scheme.

  20. Case report of sump syndrome after laser conjunctivodacryocystorhinostomy.

    PubMed

    Goel, Ruchi; Kishore, Divya; Kumar, Sushil; Agarwal, Tushar; Nagpal, Smriti; Apoorva, A G

    2015-01-01

    The sump syndrome was initially described in relation to patients who had undergone external dacryocystorhinostomy. Here we report a case of sump syndrome that developed following laser conjunctivodacryocystorhinostomy (CDCR) due to tube displacement after a bout of forceful sneezing. Unlike cases of external dacryocystorhinostomy where flaps are sutured, there is a potential space created by the sac remnants in laser CDCR. Hence, any displacement of the tube will lead to the improper drainage of secretions with superadded infections of the contents (as occurred in this case). Therefore, in laser CDCR, it is imperative to create an appropriately placed osteotomy with a correctly sized tube that is well secured to avoid displacement along with patient education regarding tube care. PMID:25960734

  1. Case Report of Sump Syndrome after Laser Conjunctivodacryocystorhinostomy

    PubMed Central

    Goel, Ruchi; Kishore, Divya; Kumar, Sushil; Agarwal, Tushar; Nagpal, Smriti; Apoorva, A.G.

    2015-01-01

    The sump syndrome was initially described in relation to patients who had undergone external dacryocystorhinostomy. Here we report a case of sump syndrome that developed following laser conjunctivodacryocystorhinostomy (CDCR) due to tube displacement after a bout of forceful sneezing. Unlike cases of external dacryocystorhinostomy where flaps are sutured, there is a potential space created by the sac remnants in laser CDCR. Hence, any displacement of the tube will lead to the improper drainage of secretions with superadded infections of the contents (as occurred in this case). Therefore, in laser CDCR, it is imperative to create an appropriately placed osteotomy with a correctly sized tube that is well secured to avoid displacement along with patient education regarding tube care. PMID:25960734

  2. Recirculating rotary gas compressor

    DOEpatents

    Weinbrecht, John F.

    1992-01-01

    A positive displacement, recirculating Roots-type rotary gas compressor which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits (24 and 26) which return compressed discharge gas to the compressor housing (14), where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers (10 and 12) and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor.

  3. Recirculating rotary gas compressor

    DOEpatents

    Weinbrecht, J.F.

    1992-02-25

    A positive displacement, recirculating Roots-type rotary gas compressor is described which operates on the basis of flow work compression. The compressor includes a pair of large diameter recirculation conduits which return compressed discharge gas to the compressor housing, where it is mixed with low pressure inlet gas, thereby minimizing adiabatic heating of the gas. The compressor includes a pair of involutely lobed impellers and an associated port configuration which together result in uninterrupted flow of recirculation gas. The large diameter recirculation conduits equalize gas flow velocities within the compressor and minimize gas flow losses. The compressor is particularly suited to applications requiring sustained operation at higher gas compression ratios than have previously been feasible with rotary pumps, and is particularly applicable to refrigeration or other applications requiring condensation of a vapor. 12 figs.

  4. Pump tank divider plate for sump suction sodium pumps

    DOEpatents

    George, John A.; Nixon, Donald R.

    1977-01-01

    A circular plate extends across the diameter of "sump suction" pump, with a close clearance between the edge of the plate and the wall of the pump tank. The plate is located above the pump impeller, inlet and outlet flow nozzles but below the sodium free surface and effectively divides the pump tank into two separate chambers. On change of pump speed, the close fitting flow restriction plate limits the rate of flow into or out of the upper chamber, thereby minimizing the rate of level change in the tank and permitting time for the pump cover gas pressure to be varied to maintain an essentially constant level.

  5. Evaluation of feed and feeding regime on growth performance, flesh quality and fecal viscosity of Atlantic salmon ( Salmo salar L.) in recirculating aquaculture systems

    NASA Astrophysics Data System (ADS)

    Sun, Guoxiang; Liu, Ying; Li, Yong; Li, Xian; Wang, Shunkui

    2015-10-01

    The effects of different feeds and feeding regimes on growth performance, flesh quality and fecal viscosity of Atlantic salmon ( Salmo salar L.) in recirculating aquaculture systems (RAS) were investigated. Fish (initial body weight of 1677 g ± 157 g) were fed with four commercial feeds (Nosan salmon-NS, Aller gold-AG, Skretting salmon-SS and Han ye-HY) in two feeding regimes (80% and 100% satiation) for 78 d. The results showed that salmon specific growth ratio (SGR) and weight gain ratio (WGR) were significantly affected by feed type and feeding regime ( P < 0.05). Feed conversion ratio (FCR) varied between 0.93 and 3.40, which was significantly affected by feed type ( P < 0.05), and slightly improved with increased satiation degree. The activities of digestive enzymes including protease, lipase and amylase were also significantly affected by feed type and feeding regime ( P < 0.05), increasing with satiation degree. Flesh qualities for vitamin E, hydroxyproline (HYP), liquid loss and muscle pH among all groups showed significant differences ( P < 0.05), ranging from 26.67 to 29.67, while no obvious difference was found in flesh color. Fecal viscosity for different treatments showed no significant difference, though improvement was found in 100% satiation group. From present experiment, it was concluded that both feed type and feeding regime can affect the important quality attributes of Atlantic salmon.

  6. Corrosion in a STP Sump. (Subtitle: What Causes It and What Can Be Done About It?)

    EPA Science Inventory

    State regulators have noticed extensive corrosion in the sumps for the submersible turbine pump (STP) of an underground storage tanks storing gasoline and E85. Acetic acid produced by biodegradation of ethanol that found its way into the sump is one plausible explanation. Resea...

  7. Two-phase numerical study of the flow field formed in water pump sump: influence of air entrainment

    NASA Astrophysics Data System (ADS)

    Bayeul-Lainé, A. C.; Simonet, S.; Bois, G.; Issa, A.

    2012-11-01

    In a pump sump it is imperative that the amount of non-homogenous flow and entrained air be kept to a minimum. Free air-core vortex occurring at a water-intake pipe is an important problem encountered in hydraulic engineering. These vortices reduce pump performances, may have large effects on the operating conditions and lead to increase plant operating costs.This work is an extended study starting from 2006 in LML and published by ISSA and al. in 2008, 2009 and 2010. Several cases of sump configuration have been numerically investigated using two specific commercial codes and based on the initial geometry proposed by Constantinescu and Patel. Fluent and Star CCM+ codes are used in the previous studies. The results, obtained with a structured mesh, were strongly dependant on main geometrical sump configuration such as the suction pipe position, the submergence of the suction pipe on one hand and the turbulence model on the other hand. Part of the results showed a good agreement with experimental investigations already published. Experiments, conducted in order to select best positions of the suction pipe of a water-intake sump, gave qualitative results concerning flow disturbances in the pump-intake related to sump geometries and position of the pump intake. The purpose of this paper is to reproduce the flow pattern of experiments and to confirm the geometrical parameter that influences the flow structure in such a pump. The numerical model solves the Reynolds averaged Navier-Stokes (RANS) equations and VOF multiphase model. STAR CCM+ with an adapted mesh configuration using hexahedral mesh with prism layer near walls was used. Attempts have been made to calculate two phase unsteady flow for stronger mass flow rates and stronger submergence with low water level in order to be able to capture air entrainment. The results allow the knowledge of some limits of numerical models, of mass flow rates and of submergences for air entrainment. In the validation of this

  8. Growth performance, fillet quality, and reproductive maturity of rainbow trout (Oncorhynchus mykiss) cultured to 5 kilograms within freshwater recirculating systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rainbow trout are commonly cultured within aquaculture systems to one pound or less and marketed as pan-sized fillets. Production of larger rainbow trout provides a distinguishable product. Research that describes the growth performance and fillet quality of large rainbow trout is limited, particula...

  9. Mill recirculation system

    SciTech Connect

    Musto, R.L.

    1984-10-23

    A mill recirculation system that is operative for purposes of effecting the pulverization and firing of solid fuels, while yet possessing all of the desirable features of a direct fired system. The subject system includes pulverizer means classifier means and burner means as well as a preestablished fluid flow path by which the pulverizer means and the classifier means are interconnected in fluid flow relation with the burner means. In accord with the mode of operation of the subject mill recirculation system a stream of solid fuel is made to flow along the fluid flow path such that the solid fuel is pulverized in the pulverizer means, classified according to particle size in the classifier means and fired in the burner means. Further, a stream of a suitable gaseous medium is made to flow along the flow path such that the gaseous medium is operative to cause the solid fuel to be conveyed therewith through the pulverizer means while being dried thereby and to be conveyed therewith from the pulverizer means to the classifier means. At the classifier means a separation is had of the stream of the gaseous medium such that a portion of the gaseous medium is recirculated along with the oversize solid fuel particles bach to the pulverizer means, while the remainder of the gaseous medium is operative to convey the solid fuel particles that are of the desired size from the classifier means to the burner means for burning, i.e., firing, in the latter.

  10. Comparing the effects of high vs. low nitrate on the health, performance, and welfare of juvenile rainbow trout Oncorhynchus mykiss within water recirculating aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research indicates that rainbow trout (Oncorhynchus mykiss) begin to exhibit health and welfare problems when cultured within water recirculating aquaculture systems (WRAS) operated at low exchange (6.7 days hydraulic retention time) and a mean feed loading rate of 4.1 kg feed/m3 daily make...

  11. Design and performance of recirculating systems for Atlantic salmon (Salmo salar) at the USDA ARS National Cold Water Marine Aquaculture Center (Franklin, Maine)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atlantic salmon cultured in the NCWMAC breeding program have grown well in the fish culture systems during the first 3 years of operation. The systems were operated at approximately 98% reuse (2% makeup water on the basis of flow rate). The water recirculating systems maintained acceptable water qua...

  12. Development of a building sump database for the Y-12 Plant, Oak Ridge, Tennessee

    SciTech Connect

    Sepanski, R.J.; Field, S.M.

    1997-07-01

    Operations at the Oak Ridge Y-12 Plant have resulted in contamination of Upper East Fork Poplar Creek (UEFPC) and shallow groundwater through soil erosion, infiltration, and outfall discharges. The contamination of groundwater has been documented for nearly two decades, largely through well monitoring efforts. This study represents the first effort to formally identify and compile location data on sumps at the Y-12 Plant, several of which are known or are suspected to pump groundwater. Operation of several of these sumps have been documented to affect groundwater hydraulics and contaminant pathways. This report presents preliminary results of an investigation attempting to identify sources of data on building sumps that have not previously been incorporated into existing Y-12 Plant groundwater databases. This investigation involved acquiring information on building sumps, such as location, building number, water source, discharge location, and availability of analytical data. This information was used to construct an ARC/INFO database capable of simultaneously storing spatial data on sump locations and attribute information concerning the operation of individual building sumps. This database will be referred to hereafter as the Y-12 Plant Building Sump Database.

  13. SAFL Baffle retrofit for suspended sediment removal in storm sewer sumps.

    PubMed

    Howard, Adam; Mohseni, Omid; Gulliver, John; Stefan, Heinz

    2011-11-15

    Standard sumps (manholes) provide a location for pipe junctions and maintenance access in stormwater drainage systems. Standard sumps can also remove sand and silt particles from stormwater, but have a high propensity for washout of the collected sediment. With appropriate maintenance these sumps may qualify as a stormwater best management practice (BMP) device for the removal of suspended sediment from stormwater runoff. To decrease the maintenance frequency and prevent standard sumps from becoming a source of suspended sediment under high flow conditions, a porous baffle, named the SAFL Baffle, has been designed and tested as a retrofit to the sump. Multiple configurations with varying percent open area and different angles of attack were evaluated in scale models. An optimum configuration was then constructed at the prototype scale and evaluated for both removal efficiency and washout. Results obtained with the retrofit indicate that with the right baffle dimensions and porosity, sediment washout from the sump at high flow rates can be almost eliminated, and removal efficiency can be significantly increased at low flow rates. Removal efficiency and washout functions have been developed for standard sumps retrofitted with the SAFL Baffle. The results of this research provide a new, versatile stormwater treatment device and implemented new washout and removal efficiency testing procedures that will improve research and development of stormwater treatment devices. PMID:21943570

  14. High ratio recirculating gas compressor

    DOEpatents

    Weinbrecht, John F.

    1989-01-01

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor.

  15. High ratio recirculating gas compressor

    DOEpatents

    Weinbrecht, J.F.

    1989-08-22

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

  16. Airlift recirculation well test results -- Southern sector

    SciTech Connect

    White, R.M.; Hiergesell, R.A.

    1997-08-01

    Chlorinated solvents used in the A and M-Areas at the Savannah River Site (SRS) from 1952--1982 have contaminated the groundwater under the site. A plume of groundwater contaminated with trichloroethylene (TCE) and perchloroethylene (PCE) in the Lost Lake aquifer is moving generally southward with the natural flow of groundwater. To comply with the requirements of the current SCDHEC Part B Permit, a series of wells is being installed to contain and treat the plume. Airlift Recirculation Wells (ARW) are a new and innovative technology with potential for more cost effective implementation than conventional pump and treat systems. Two Airlift Recirculation Wells have been installed and tested to quantify performance parameters needed to locate a line of these wells along the leading edge of the contaminant plume. The wells proved to be very sensitive to proper development, but after this requirement was met, performance was very good. The Zone of Capture has been estimated to be within a radius of 130--160 ft. around the wells. Thus a line of wells spaced at 250 ft. intervals could intercept the contaminant plume. At SSR-012, TCE was stripped from the groundwater at approximately 1.2 lb./day. The longer term effect of the recirculation wells upon the plume and the degree of recirculation within the aquifer itself will require additional data over a longer time period for an accurate review. Data collection is ongoing.

  17. Mind the Sump! – Diagnostic Challenge of a Rare Complication of Choledochoduodenostomy

    PubMed Central

    Zeuge, Ulf; Fehr, Martin; Meyenberger, Christa; Sulz, Michael Christian

    2014-01-01

    Sump syndrome is a rare long-term complication of side-to-side choledochoduodenostomy (CDD), a common surgical procedure in patients with biliary tract disease in the era before endoscopic retrograde cholangiopancreatography (ERCP). Frequently only pneumobilia, serving as sign for functioning biliary-enteric anastomosis, is reminiscent of the former surgery. We present the case of an 81-year-old patient with sump syndrome who presented with clinical signs of ascending cholangitis, decades after the initial CDD procedure. Finally the detailed medical history that was taken very thoroughly in combination with the presence of pneumobilia led to the suspicion of sump syndrome. Sump syndrome was diagnosed by ERCP, and after endoscopic debris extraction and antibiotic treatment the patient recovered quickly. In the ERCP era little is known about CDD and its long-term complications, especially by young colleagues and trainees. Therefore this report provides an excellent opportunity to refresh the knowledge and raise awareness for this syndrome. PMID:25520606

  18. Combustion-gas recirculation system

    DOEpatents

    Baldwin, Darryl Dean

    2007-10-09

    A combustion-gas recirculation system has a mixing chamber with a mixing-chamber inlet and a mixing-chamber outlet. The combustion-gas recirculation system may further include a duct connected to the mixing-chamber inlet. Additionally, the combustion-gas recirculation system may include an open inlet channel with a solid outer wall. The open inlet channel may extend into the mixing chamber such that an end of the open inlet channel is disposed between the mixing-chamber inlet and the mixing-chamber outlet. Furthermore, air within the open inlet channel may be at a pressure near or below atmospheric pressure.

  19. Effects of sludge recirculation rate and mixing time on performance of a prototype single-stage anaerobic digester for conversion of food wastes to biogas and energy recovery.

    PubMed

    Ratanatamskul, Chavalit; Saleart, Tawinan

    2016-04-01

    Food wastes have been recognized as the largest waste stream and accounts for 39.25 % of total municipal solid waste in Thailand. Chulalongkorn University has participated in the program of in situ energy recovery from food wastes under the Ministry of Energy (MOE), Thailand. This research aims to develop a prototype single-stage anaerobic digestion system for biogas production and energy recovery from food wastes inside Chulalongkorn University. Here, the effects of sludge recirculation rate and mixing time were investigated as the main key parameters for the system design and operation. From the results obtained in this study, it was found that the sludge recirculation rate of 100 % and the mixing time of 60 min per day were the most suitable design parameters to achieve high efficiencies in terms of chemical oxygen demand (COD), total solids (TS), and total volatile solid (TVS) removal and also biogas production by this prototype anaerobic digester. The obtained biogas production was found to be 0.71 m(3)/kg COD and the composition of methane was 61.6 %. Moreover, the efficiencies of COD removal were as high as 82.9 % and TVS removal could reach 83.9 % at the optimal condition. Therefore, the developed prototype single-stage anaerobic digester can be highly promising for university canteen application to recover energy from food wastes via biogas production. PMID:25864735

  20. Analysis on pressure characteristics of pump turbine guide bearing rotating sump based on VOF model

    NASA Astrophysics Data System (ADS)

    Zhai, L. M.; Yao, Z.; Huang, Q. S.; Xiao, Y. X.; Wang, Z. W.

    2013-12-01

    With the technology of Computational Fluid Dynamics (CFD), this paper conducts a 3D numerical simulation for the oil and gas flow field in the Pump turbine guide bearing rotating sump. VOF model is adopted in this simulation. This study calculates distribution of the oil-air phase and characteristics of the pressure. The influence of sump rotating speed, oil level and oil viscosity on the pressure at the inlet of oil-immersion plate are discussed. The results demonstrate that the static pressure at the inlet is roughly proportional to oil level. Too low level may result in the separation between lubrication oil and supply hole on the oil-immersion plate, which then disables the oil supply. The static pressure at the inlet increases parabola as the sump rotating speed increases. To ensure the supply pressure, the unit is not suitable for long time operation under low rotating speed. The temperature-viscosity effect of the lubricant oil has little influence on the oil pressure at the supply hole. This paper provides a theoretical base for the safe design and operation of the pump turbine rotating sump, and offers the inlet boundary condition for the analysis of the oil film dynamic characteristics of the turbine guide bearing.

  1. Characterization of the flow in the molten metal sump during direct chill aluminum casting

    NASA Astrophysics Data System (ADS)

    Reese, Jason M.

    1997-06-01

    A recent analytical model for the liquid aluminum flow in a direct chill (DC) casting sump has been investigated and the scaling coefficients evaluated. The magnitudes of flow-field features, such as the depth of the temperature stratification in the sump and the velocity of the metal in the thermal boundary layer close to the solidification front, have been calculated. The results broadly agree with recent full numerical calculations of the flow in the sump. The variation of these essential flow features has been investigated across a range of typical ingot sizes, casting speeds, and superheats, and critical macro-casting-parameter combinations have been identified. The limitations of the model are discussed and the possible effects the identified structure has on macrosegregation are briefly explored. Finally, the influence on the flow field of the method of feeding the ingot is investigated, and it is concluded that the model and these results are not invalidated if the feeding is nonuniform over the top surface of the sump.

  2. Interior sump/sewerage room from entry, view facing northeast U.S. ...

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

    Interior sump/sewerage room from entry, view facing northeast - U.S. Naval Base, Pearl Harbor, Dry Dock No. 1, Pumpwell, By-Pass Valve & Saltwater Pumphouse, North end of Fifth Street, between Dry Dock No. 1 & Facility GD2 , Pearl City, Honolulu County, HI

  3. Interior of sump/sewerage room looking up four levels, ladder on ...

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

    Interior of sump/sewerage room looking up four levels, ladder on pipe, view facing southwest - U.S. Naval Base, Pearl Harbor, Dry Dock No. 1, Pumpwell, By-Pass Valve & Saltwater Pumphouse, North end of Fifth Street, between Dry Dock No. 1 & Facility GD2 , Pearl City, Honolulu County, HI

  4. Case study of controlled recirculation at a Wyoming trona mine

    PubMed Central

    Pritchard, C.; Scott, D.; Frey, G.

    2015-01-01

    Controlled recirculation has been used in the metal/nonmetal mining industry for energy savings when heating and cooling air, in undersea mining and for increasing airflow to mining areas. For safe and effective use of controlled district recirculation, adequate airflow to dilute contaminants must exist prior to implementation, ventilation circuit parameters must be accurately quantified, ventilation network modeling must be up to date, emergency planning scenarios must be performed and effective monitoring and control systems must be installed and used. Safety and health issues that must be considered and may be improved through the use of controlled district recirculation include blasting fumes, dust, diesel emissions, radon and contaminants from mine fires. Controlled recirculation methods are expected to become more widely used as mines reach greater working depths, requiring that these health and safety issues be well understood. The U.S. National Institute for Occupational Safety and Health (NIOSH) conducted two controlled recirculation tests over three days at a Wyoming trona mine, utilizing an inline booster fan to improve airflow to a remote and difficult-to-ventilate development section. Test results were used to determine the effect that recirculation had on air qualities and quantities measured in that section and in other adjacent areas. Pre-test conditions, including ventilation quantities and pressures, were modeled using VnetPC. During each test, ventilation quantities and pressures were measured, as well as levels of total dust. Sulfur hexafluoride (SF6) tracer gas was used to simulate a mine contaminant to monitor recirculation wave cycles. Results showed good correlation between the model results and measured values for airflows, pressure differentials, tracer gas arrival times, mine gasses and dust levels. PMID:26251567

  5. Recirculated and Energy Recovered Linacs

    SciTech Connect

    Geoffrey Krafft

    2003-05-01

    Linacs that are recirculated share many characteristics with ordinary linacs, including the ability to accelerate electron beams from an injector to high energy with relatively little (normalized) emittance growth and the ability to deliver ultrashort bunch duration pulses to users. When such linacs are energy recovered, the additional possibility of accelerating very high average beam current arises. Because this combination of beam properties is not possible from either a conventional linac, or from storage rings where emittance and pulse length are set by the equilibrium between radiation damping and quantum excitation of oscillations about the closed orbit, energy recovered linacs are being considered for an increasing variety of applications. These possibilities extend from high power free-electron lasers and recirculated linac light sources, to electron coolers for high energy colliders or actual electron-ion colliding- beam machines based on an energy recovered linac for the electrons.

  6. Benson Beach Demonstration Project: Composition and Abundance of Biota at Three Alternative Sump Sites

    SciTech Connect

    Williams, Greg D.; Pearson, Walter H.; Evans, Nathan R.; Anderson, Michael G.

    2004-01-15

    The Portland District of the U.S. Army Corps of Engineers is investigating plans to provide sediment to nourish beaches north of the Mouth of the Columbia River (MCR). Under the currently designed proposal, sediment dredged from the MCR will be temporarily stored at one of three proposed areas south of the North Jetty before being redredged and moved by a cutterhead pipeline dredge over the jetty to nourish Benson Beach. Resulting potential impacts to resident Dungeness crab (Cancer magister) and fishes represent one of the criteria for evaluating each of the alternative locations. To establish the species composition and relative abundance of crabs and fishes associated with each of the three proposed sump areas, researchers from the Pacific Northwest National Laboratory Marine Sciences Division completed nine field sampling trips from July 8, 2003, to November 1, 2003, for a total of 113 successful trawls comprising an area of over 7.4 ha (74,156 m2). This report documents the results of that effort. To understand the relative risk of losses to crab populations associated with dredging impacts at the sump alternative areas, it is recommended that a modified dredge impact model be developed using the data collected in this study. This model should estimate crab adult equivalent loss and associated error rates to gain a population-level perspective on the potential entrainment impacts at each of the three alternative sump areas. As well, a sustained survey of Dungeness crab distribution and movement within the Columbia River estuary would clarify the relative value of the sump areas as a migratory corridor for crab populations, and support management decisions relative to issues associated with dredged material handling and disposal.

  7. Industrial Energy Conservation, Forced Internal Recirculation Burner

    SciTech Connect

    Joseph Rabovitser

    2003-06-19

    The overall objective of this research project is to develop and evaluate an industrial low NOx burner for existing and new gas-fired combustion systems for intermediate temperature (1400 degree to 2000 degree F) industrial heating devices such as watertube boilers and process fluid heaters. A multi-phase effort is being pursued with decision points to determine advisability of continuance. The current contract over Phases II and III of this work. The objectives of each phase are as follows. Phase II - to design, fabricate, and evaluate prototype burners based on the Forced Internal Recirculation (FIR) concept. Phase III - to evaluate the performance of an FIR burner under actual operating conditions in a full-scale field test and establish the performance necessary for subsequent commercialization

  8. Recirculation in multiple wave conversions

    SciTech Connect

    Kaufman, A. N.; Brizard, A.J.; Kaufman, A.N.; Tracy, E.R.

    2008-07-30

    A one-dimensional multiple wave-conversion model is constructed that allows energy recirculation in ray phase space. Using a modular eikonal approach, the connection coefficients for this model are calculated by ray phase-space methods. Analytical results (confirmed numerically) show that all connection coefficients exhibit interference effects that depend on an interference phase, calculated from the coupling constants and the area enclosed by the intersecting rays. This conceptual model, which focuses on the topology of intersecting rays in phase space, is used to investigate how mode conversion between primary and secondary waves is modified by the presence of a tertiary wave.

  9. The effects of ozonation on performance, health and welfare of rainbow trout Oncorhynchus mykiss in low-exchange water recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A controlled four-month trial was conducted to compare the effects of ozonation (oxidation-reduction potential setpoint = 250 mV) versus no ozonation on rainbow trout Oncorhynchus mykiss performance, health, and welfare in replicated WRAS operated at low exchange rates (0.26% of the total recirculat...

  10. Assessment of residual heat removal and containment spray pump performance under air and debris ingesting conditions. [PWR

    SciTech Connect

    Kamath, P.S.; Tantillo, T.J.; Swift, W.L.

    1982-09-01

    This report presents an assessment of the performance of Residual Heat Removal (RHR) and Containment Spray (CS) pumps during the recirculation phase of reactor core and containment cooldown following a Loss-of-Coolant Accident (LOCA). The pumped fluid is expected to contain debris such as insulation and may ingest air depending on sump conditions. Findings are based on information collected from the literature and from interviews with pump and seal manufacturers. These findings show that for pumps at normal flow rates operating with sufficient Net Positive Suction Head (NPSH), pump performance degradation is negligible if air ingestion quantities are less than 2% by volume. For air ingestion between 3% and 15% by volume, head degradation depends on individual pump design and operating conditions and for air quantities greater than 15% performance of most pumps will be fully degraded. Also, small quantities of air will increase NPSH requirements for these pumps. For the types and quantities of debris likely to be present in the recirculating fluid, pump performance degradation is expected to be negligible.

  11. Gas turbine combustor stabilization by heat recirculation

    NASA Technical Reports Server (NTRS)

    Ganji, A.; Short, J.; Branch, M. C.; Oppenheim, A. K.

    1975-01-01

    The feasibility of heat recirculation for stabilization of lean mixtures and emission reduction has been studied in detail for a typical aircraft gas turbine combustor. Thermodynamic calculations have indicated temperature and heat recirculation rates for operation of the combustor over a range of combustion zone equivalence ratios and for varying modes of desired engine operation. Calculations indicate the feasibility of stabilizing the combustion zone at equivalence ratios as low as 0.2 with achievable heat recirculation rates. Detailed chemical kinetic calculations suggest that combustor heat release is maintained with reaction completion substantially before the NO forming reactions, even though CO is rapidly oxidized in this same region.

  12. Lattice Design for the LHEC Recirculating Linac

    SciTech Connect

    Sun, Yipeng; Eide, Anders; Zimmermann, Frank; Adolphsen, Chris; /SLAC

    2011-05-20

    In this paper, we present a lattice design for the Large Hadron Electron Collider (LHeC) recirculating linac. The recirculating linac consists of one roughly 3-km long linac hosting superconducting RF (SRF) accelerating cavities, two arcs and one transfer line for the recirculation. In two passes through a pulsed SRF linac the electron beam can get a maximum energy of 140 GeV. Alternatively, in the Energy Recovery Linac (ERL) option the beam passes through a CW linac four times (two passes for acceleration and two for deceleration) for a maximum energy of 60 GeV.

  13. Coastal and synoptic recirculation affecting air pollutants dispersion: A numerical study

    NASA Astrophysics Data System (ADS)

    Levy, Ilan; Mahrer, Yizhak; Dayan, Uri

    This study examines the spatial distribution of potential recirculation over the East Mediterranean Sea, and the combined effect of synoptic and meso-scale recirculations on plume dispersion in the region. For this purpose, three case studies are performed by the RAMS-HYPACT modeling system, each for a different synoptic scale flow pattern. Both a quantitative measure of the recirculation potential at each grid cell and particle dispersion are calculated. Although the recirculation index is an Eulerian quantity for the wind field and plume dispersion is a manifestation of the Lagrangian behavior of the wind, good correlation is found between the two. Several locations are identified as having high recirculation potential, including southern Cyprus, the coasts of Israel and Lebanon, the eastern slopes of the Judean Mountains and the Haifa Bay in particular. In the latter location, high recirculation potential could be explained by strong interaction between the land-sea surfaces, curvature of the bay and proximity of the Carmel ridge. It is shown that the synoptic and meso-scale recirculations may, under certain conditions, act together and at the same time in determining particle distribution. Under weak synoptic scale flows, particles are recirculated over the entire East Mediterranean Sea basin, returning onshore after a period of 2-3 days to join freshly emitted particles. At the same time, near-shore land-sea breeze effects cause particles to recirculate on smaller time scales of less then one day, sometimes passing as much as three times over the same airshed. A single elevated emission source is shown to have the potential to impair air quality at a coastal strip as long as 100-200 km upon returning onshore.

  14. Recirculating cross-correlation detector

    DOEpatents

    Andrews, W.H. Jr.; Roberts, M.J.

    1985-01-18

    A digital cross-correlation detector is provided in which two time-varying signals are correlated by repetitively comparing data samples stored in digital form to detect correlation between the two signals. The signals are sampled at a selected rate converted to digital form, and stored in separate locations in separate memories. When the memories are filled, the data samples from each memory are first fed word-by-word through a multiplier and summing circuit and each result is compared to the last in a peak memory circuit and if larger than the last is retained in the peak memory. Then the address line to leading signal memory is offset by one byte to affect one sample period delay of a known amount in that memory and the data in the two memories are then multiplied word-by-word once again and summed. If a new result is larger than a former sum, it is saved in the peak memory together with the time delay. The recirculating process continues with the address of the one memory being offset one additional byte each cycle until the address is shifted through the length of the memory. The correlation between the two signals is indicated by the peak signal stored in the peak memory together with the delay time at which the peak occurred. The circuit is faster and considerably less expensive than comparable accuracy correlation detectors.

  15. Flume simulation of sedimentation in recirculating flow

    SciTech Connect

    Schmidt, J.C. ); Rubin, D.M. ); Ikeda, H. )

    1990-05-01

    A 4-m-wide flume at the University of Tsukuba Environmental Research Center was used to simulate flow conditions near debris fans in bedrock gorges. Flow was constricted to 2 m by a semicircular obstruction. During the authors experiments (discharge = 600 L/sec; Froude number of constricted flow = 1) a zone of recirculating current extended 25-30 m downstream from the separation point at the constriction. The pattern and velocity of surface flow was determined using time-lapse photography; subsurface velocity was measured with a two-dimensional electromagnetic current meter. During 32-hr of run time, a fine, very coarse sand mixture was fed into the flow at a rate between 0.5-1 kg/sec. Oscillation ripples developed beneath the separation surface that bounds the recirculation zone, and upstream-migrating dunes and ripples developed within the recirculation zone upstream from the reattachment point. A mid-channel expansion bar was deposited downstream from the reattachment point. Sedimentation within the recirculation zone continued by vertical aggradation and by upstream migration of dunes and ripples. Sediments within the recirculation zone were areally sorted with the finest sediment deposited near the separation point. These patterns are consistent with field observations of bars along the Colorado River in the Grand Canyon.

  16. Diagnostics For Recirculating And Energy Recovered Linacs

    SciTech Connect

    Geoffrey A. Krafft; Jean-Claude Denard

    2002-12-18

    In this paper, the electron beam diagnostics developed for recirculating electron accelerators will be reviewed. The main novelties in dealing with such accelerators are: to have sufficient information and control possibilities for the longitudinal phase space, to have means to accurately set the recirculation path length, and to have a means to distinguish the beam passes on measurements of position in the linac proper. The solutions to these problems obtained at Jefferson Laboratory and elsewhere will be discussed. In addition, more standard instrumentation (profiling and emittance measurements) will be reviewed in the context of recirculating linacs. Finally, and looking forward, electron beam diagnostics for applications to high current energy recovered linacs will be discussed.

  17. Peach bottom recirculation piping replacement ALARA program

    SciTech Connect

    Englesson, G.A.; Hilsmeier, A.E.; Mann, B.J.

    1986-01-01

    In late 1983, Philadelphia Electric Company (PECo) began detailed planning to replace the recirculation, residual heat removal, and part of the reactor water cleanup piping of the Peach Bottom Unit 2 reactor. Included in this work was an estimate of the collective exposure expected during piping replacement. That initial estimate, 1945 man-rem, is compared with the actual collective dose incurred during the piping replacement program. Also included are the exposures incurred during two additional tasks (safe end replacement and recirculation pump disassembly and decontamination) not considered in the initial estimate.

  18. Multi-Point Interferometric Rayleigh Scattering using Dual-Pass Light Recirculation

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Danehy, Paul M.; Cutler, Andrew D.

    2008-01-01

    This paper describes for the first time an interferometric Rayleigh scattering system using dual-pass light recirculation (IRS-LR) capable of simultaneously measuring at multiple points two orthogonal components of flow velocity in combustion flows using single shot laser probing. An additional optical path containing the interferometer input mirror, a quarter-wave plate, a polarization dependent beam combiner, and a high reflectivity mirror partially recirculates the light that is rejected by the interferometer. Temporally- and spatially-resolved acquisitions of Rayleigh spectra in a large-scale combustion-heated supersonic axi-symmetric jet were performed to demonstrate the technique. Recirculating of Rayleigh scattered light increases the number of photons analyzed by the system up to a factor of 1.8 compared with previous configurations. This is equivalent to performing measurements with less laser energy or performing measurements with the previous system in gas flows at higher temperatures.

  19. Nitrogen removal in recirculated duckweed ponds system.

    PubMed

    Benjawan, L; Koottatep, T

    2007-01-01

    Duckweed-based ponds (DWBPs) have the potential for nitrogen (N) removal from wastewater; however, operational problems such as duckweed die-off regularly occur. In this study, effluent recirculation was applied to the DWBPs to solve the above problem as well as to investigate N removal mechanisms. Two pilot scale recirculated DWBPs were employed to treat municipal wastewater. The average removal efficiencies for TN, TKN and NH4-N were 75%, 89% and 92%, respectively at TN loading of 1.3 g/m2.d and were 73%, 74% and 76%, respectively at TN loading of 3.3 g/m2.d. The effluent of the system under both operational conditions had stable quality and met the effluent standard. Duckweed die-off was not observed during the study, which proves the system stability and effluent recirculation which is thought to be a reason. N-mass balance revealed that nitrification-denitrification and duckweed uptake play major roles in these recirculated DWBPs. The rates of nitrification-denitrification were increased as TN loading was higher, which might be an influence from an abundance of N and a suitable condition. The rates of N uptake by duckweed were found similar and did not depend on the higher TN loading applied, as the duckweed has limited capacity to assimilate it. PMID:17591202

  20. Recirculation as a Form of Conservation.

    ERIC Educational Resources Information Center

    Gordon, Jeffrey J.

    1982-01-01

    Discusses nine forms of conservation practices: sustained yield, repair, careful use, greater efficiency, lower consumption, doing without, substitution, new resources, and recycling. Suggests recirculation (saving goods from discard and from being broken down in a new manufacturing stage) as a 10th form of conservation practice. (Author/JN)

  1. Better Management Practices for Recirculating Aquaculture Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Under the 2004 federal aquaculture effluent limitation guidelines (Federal Register 2004), recirculating aquaculture systems with an annual production exceeding 45,454 kg (100,000 pounds) are classified as concentrated aquatic animal production (CAAP) facilities and are required to obtain a National...

  2. 21 CFR 880.5045 - Medical recirculating air cleaner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Medical recirculating air cleaner. 880.5045... Therapeutic Devices § 880.5045 Medical recirculating air cleaner. (a) Identification. A medical recirculating air cleaner is a device used to remove particles from the air for medical purposes. The device...

  3. 21 CFR 880.5045 - Medical recirculating air cleaner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Medical recirculating air cleaner. 880.5045... Therapeutic Devices § 880.5045 Medical recirculating air cleaner. (a) Identification. A medical recirculating air cleaner is a device used to remove particles from the air for medical purposes. The device...

  4. 21 CFR 880.5045 - Medical recirculating air cleaner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical recirculating air cleaner. 880.5045... Therapeutic Devices § 880.5045 Medical recirculating air cleaner. (a) Identification. A medical recirculating air cleaner is a device used to remove particles from the air for medical purposes. The device...

  5. Monitoring extent of moisture variations due to leachate recirculation in an ELR/bioreactor landfill using resistivity imaging.

    PubMed

    Manzur, Shahed Rezwan; Hossain, Md Sahadat; Kemler, Vance; Khan, Mohammad Sadik

    2016-09-01

    Bioreactor or enhanced leachate recirculation (ELR) landfills are designed and operated for accelerated waste stabilization, accelerated decomposition, and an increased rate of gas generation. The major aspects of a bioreactor landfill are the addition of liquid and the recirculation of collected leachate back into the waste mass through the subsurface leachate recirculation system (LRS). The performance of the ELR landfill largely depends on the existing moisture content within the waste mass; therefore, it is of utmost importance to determine the moisture variations within the landfill. Traditionally, the moisture variation of the ELR landfill is determined by collecting samples through a bucket auger boring from the landfill, followed by laboratory investigation. Collecting the samples through a bucket auger boring is time consuming, labor intensive, and cost prohibitive. Moreover, it provides the information for a single point within the waste mass, but not for the moisture distribution within the landfill. Fortunately, 2D resistivity imaging (RI) can be performed to assess the moisture variations within the landfill and provide a continuous image of the subsurface, which can be utilized to evaluate the performance of the ELR landfill. During this study, the 2D resistivity imaging technique was utilized to determine the moisture distribution and moisture movement during the recirculation process of an ELR landfill in Denton, Texas, USA. A horizontal recirculation pipe was selected and monitored periodically for 2.5years, using the RI technique, to investigate the performance of the leachate recirculation. The RI profile indicated that the resistivity of the solid waste decreased as much as 80% with the addition of water/leachate through the recirculation pipe. In addition, the recirculated leachate traveled laterally between 11m and 16m. Based on the resistivity results, it was also observed that the leachate flow throughout the pipe was non-uniform. The non

  6. Re-circulating linac vacuum system

    SciTech Connect

    Wells, Russell P.; Corlett, John N.; Zholents, Alexander A.

    2003-05-09

    The vacuum system for a proposed 2.5 GeV, 10{Mu}A recirculating linac synchrotron light source [1] is readily achievable with conventional vacuum hardware and established fabrication processes. Some of the difficult technical challenges associated with synchrotron light source storage rings are sidestepped by the relatively low beam current and short beam lifetime requirements of a re-circulating linac. This minimal lifetime requirement leads directly to relatively high limits on the background gas pressure through much of the facility. The 10{Mu}A average beam current produces very little synchrotron radiation induced gas desorption and thus the need for an ante-chamber in the vacuum chamber is eliminated. In the arc bend magnets, and the insertion devices, the vacuum chamber dimensions can be selected to balance the coherent synchrotron radiation and resistive wall wakefield effects, while maintaining the modest limits on the gas pressure and minimal outgassing.

  7. Preoperational test report, recirculation condenser cooling systems

    SciTech Connect

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Recirculation Condenser Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The four system provide condenser cooling water for vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102. Each system consists of a valved piping loop, a pair of redundant recirculation pumps, a closed-loop evaporative cooling tower, and supporting instrumentation; equipment is located outside the farm on concrete slabs. Piping is routed to the each ventilation condenser inside the farm via below-grade concrete trenches. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  8. Investigation of hydrocarbon oil transformation by gliding arc discharge: comparison of batch and recirculated configurations

    NASA Astrophysics Data System (ADS)

    Whitehead, J. Christopher; Prantsidou, Maria

    2016-04-01

    The degradation of liquid dodecane was studied in a gliding arc discharge (GAD) of humid argon or nitrogen. A batch or recirculating configuration was used. The products in the gaseous and liquid phase were analysed by infrared and chromatography and optical emission spectroscopy was used to identify the excited species in the discharge. The best degradation performance comes from the use of humid N2 but a GAD of humid argon produces fewer gas-phase products but more liquid-phase end-products. A wide range of products such as heavier saturated or unsaturated hydrocarbons both aliphatic and aromatic, and oxidation products mainly alcohols, but also aldehydes, ketones and esters are produced in the liquid-phase. The recirculating treatment mode is more effective than the batch mode increasing the reactivity and changing the product selectivities. Overall, the study shows promising results for the organic liquid waste treatment, especially in the recirculating mode.

  9. High Power Picosecond Laser Pulse Recirculation

    SciTech Connect

    Shverdin, M Y; Jovanovic, I; Semenov, V A; Betts, S M; Brown, C; Gibson, D J; Shuttlesworth, R M; Hartemann, F V; Siders, C W; Barty, C P

    2010-04-12

    We demonstrate a nonlinear crystal-based short pulse recirculation cavity for trapping the second harmonic of an incident high power laser pulse. This scheme aims to increase the efficiency and flux of Compton-scattering based light sources. We demonstrate up to 36x average power enhancement of frequency doubled sub-millijoule picosecond pulses, and 17x average power enhancement of 177 mJ, 10 ps, 10 Hz pulses.

  10. Scaling of Wakefield Effects in Recirculating Linacs

    SciTech Connect

    L. Merminga; G. R. Neil; B. C. Yunn; J. J. Bisognano

    2001-07-01

    Expressions for the induced energy spread and emittance degradation of a single bunch due to the longitudinal and transverse impedance of rf cavities at the end of a linac structure are presented. Scaling of the formulae with rf frequency is derived. Scaling of the threshold current for the multibunch, multipass beam breakup (BBU) instability in recirculating linacs with accelerator and beam parameters is also derived.

  11. Hybrid heat exchange for the compression capture of CO2 from recirculated flue gas

    SciTech Connect

    Oryshchyn, Danylo B.; Ochs, Thomas L.; Summers, Cathy A.

    2004-01-01

    An approach proposed for removal of CO2 from flue gas cools and compresses a portion of a recirculated flue-gas stream, condensing its volatile materials for capture. Recirculating the flue gas concentrates SOx, H2O and CO2 while dramatically reducing N2 and NOx, enabling this approach, which uses readily available industrial components. A hybrid system of indirect and direct-contact heat exchange performs heat and mass transfer for pollutant removal and energy recovery. Computer modeling and experimentation combine to investigate the thermodynamics, heat and mass transfer, chemistry and engineering design of this integrated pollutant removal (IPR) system.

  12. Recirculating gas separator for electric submersible

    SciTech Connect

    Powers, M.L.

    1991-01-01

    This patent describes a gas separator apparatus for a submersible well pump. It comprises: a rotary gas separator means; and recirculating means for recirculating a portion of the liquid discharged from the discharge outlet back to the separating chamber so that a gas-to-liquid ratio in the separator means is substantially lower than a gas-to-liquid ratio of well fluid entering the well fluid inlet wherein the recirculating means. This patent also describes a method of pumping liquid from a well producing well fluids having a relatively high gas-to-liquid ratio. It comprises: centrifugally separating the well fluid into a liquid and a gas with a separator located downhole in the well; directing the separated liquid toward an inlet of a submersible well pump; recycling a portion of the separated liquid to the separator; and providing an effective gas-to-liquid ratio in the separator substantially lower than a gas-to-liquid ratio of the well fluid prior to separation.

  13. Harmonic Generation in the Multifrequency Recirculating Planar Magnetron

    NASA Astrophysics Data System (ADS)

    Exelby, S. C.; Greening, G. B.; Jordan, N. M.; Simon, D.; Zhang, P.; Lau, Y. Y.; Gilgenbach, R. M.

    2015-11-01

    The Multifrequency Recirculating Planar Magnetron (MFRPM) is a high power microwave source adapted from the Recirculating Planar Magnetrona, currently under investigation at the University of Michigan. The device features 2 dissimilar periodic structures allowing for the generation of (L-band) 1- and (S-band) 2-GHz high power microwave pulses simultaneously. These distinct frequencies offer the potential for variable coupling for defense applications, such as counter-IED. Experiments have been performed on the RPM, driven by the Michigan Electron Long Beam Accelerator with a Ceramic insulator (MELBA-C) using a -300kV, 1-10 kA, 0.3-1.0 us pulse applied to the cathode. Using the Mode Control Cathodeb and a coax-to-waveguide extraction system, the MFRPM has demonstrated simultaneous production of 20 MW at 1 GHz and 10 MW at 2 GHz. The L-band oscillator also produced both 2- and 4-GHz oscillations when the S-band oscillator turns on. These harmonics persist after the S-band oscillator turns off. Ongoing work will attempt to isolate these harmonics to measure the power accurately and confirm these observations. Supported by the Office of Naval Research grant no. N00014-13-1-0566 and L-3 Communications.

  14. A one-equation turbulence model for recirculating flows

    NASA Astrophysics Data System (ADS)

    Zhang, Yang; Bai, JunQiang; Xu, JingLei; Li, Yi

    2016-06-01

    A one-equation turbulence model which relies on the turbulent kinetic energy transport equation has been developed to predict the flow properties of the recirculating flows. The turbulent eddy-viscosity coefficient is computed from a recalibrated Bradshaw's assumption that the constant a 1 = 0.31 is recalibrated to a function based on a set of direct numerical simulation (DNS) data. The values of dissipation of turbulent kinetic energy consist of the near-wall part and isotropic part, and the isotropic part involves the von Karman length scale as the turbulent length scale. The performance of the new model is evaluated by the results from DNS for fully developed turbulence channel flow with a wide range of Reynolds numbers. However, the computed result of the recirculating flow at the separated bubble of NACA4412 demonstrates that an increase is needed on the turbulent dissipation, and this leads to an advanced tuning on the self-adjusted function. The improved model predicts better results in both the non-equilibrium and equilibrium flows, e.g. channel flows, backward-facing step flow and hump in a channel.

  15. Impact of nitrate-enhanced leachate recirculation on gaseous releases from a landfill bioreactor cell.

    PubMed

    Tallec, G; Bureau, C; Peu, P; Benoist, J C; Lemunier, M; Budka, A; Presse, D; Bouchez, T

    2009-07-01

    This study evaluates the impact of nitrate injection on a full scale landfill bioreactor through the monitoring of gaseous releases and particularly N(2)O emissions. During several weeks, we monitored gas concentrations in the landfill gas collection system as well as surface gas releases with a series of seven static chambers. These devices were directly connected to a gas chromatograph coupled to a flame ionisation detector and an electron capture detector (GC-FID/ECD) placed directly on the field. Measurements were performed before, during and after recirculation of raw leachate and nitrate-enhanced leachate. Raw leachate recirculation did not have a significant effect on the biogas concentrations (CO(2), CH(4) and N(2)O) in the gas extraction network. However, nitrate-enhanced leachate recirculation induced a marked increase of the N(2)O concentrations in the gas collected from the recirculation trench (100-fold increase from 0.2 ppm to 23 ppm). In the common gas collection system however, this N(2)O increase was no more detectable because of dilution by gas coming from other cells or ambient air intrusion. Surface releases through the temporary cover were characterized by a large spatial and temporal variability. One automated chamber gave limited standard errors over each experimental period for N(2)O releases: 8.1 +/- 0.16 mg m(-2) d(-1) (n = 384), 4.2 +/- 0.14 mg m(-2) d(-1) (n = 132) and 1.9 +/- 0.10 mg m(-2) d(-1) (n = 49), during, after raw leachate and nitrate-enhanced leachate recirculation, respectively. No clear correlation between N(2)O gaseous surface releases and recirculation events were evidenced. Estimated N(2)O fluxes remained in the lower range of what is reported in the literature for landfill covers, even after nitrate injection. PMID:19297142

  16. Interaction of droplets in recirculation regions within microfluidic systems

    NASA Astrophysics Data System (ADS)

    Ghazi, Nastaran; Hosseini, Ashkan; Shojaei-Zadeh, Shahab

    2012-11-01

    We investigate the interaction of oil droplets in continuous water phase as they travel across the streamlines of a recirculation region using microfluidic devices. Oil droplets are first generated using hydrodynamic focusing and then enter a recirculation region. The droplets then keep recirculating until they are pushed out by the incoming ones. We show that the frequency of droplet generation, viscosity contrast (oil to water), and geometry determine which droplets to stay in the recirculation region and which one to leave. Using flow field simulations, we investigate the migration of droplets and their trajectories based on the geometry of the recirculation region, the bubble size, and fluid properties. Under favorable conditions, when droplets interact within the recirculation region for long enough time, the film thickness that separates the two interfaces reduces and droplets will coalesce. The proposed design thus provides a suitable platform to study droplet coalescence within microfluidic devices.

  17. Exhaust gas recirculation system for an internal combustion engine

    SciTech Connect

    Wu, Ko-Jen

    2013-05-21

    An exhaust gas recirculation system for an internal combustion engine comprises an exhaust driven turbocharger having a low pressure turbine outlet in fluid communication with an exhaust gas conduit. The turbocharger also includes a low pressure compressor intake and a high pressure compressor outlet in communication with an intake air conduit. An exhaust gas recirculation conduit fluidly communicates with the exhaust gas conduit to divert a portion of exhaust gas to a low pressure exhaust gas recirculation branch extending between the exhaust gas recirculation conduit and an engine intake system for delivery of exhaust gas thereto. A high pressure exhaust gas recirculation branch extends between the exhaust gas recirculation conduit and the compressor intake and delivers exhaust gas to the compressor for mixing with a compressed intake charge for delivery to the intake system.

  18. Exhaust gas recirculation in a homogeneous charge compression ignition engine

    DOEpatents

    Duffy, Kevin P.; Kieser, Andrew J.; Rodman, Anthony; Liechty, Michael P.; Hergart, Carl-Anders; Hardy, William L.

    2008-05-27

    A homogeneous charge compression ignition engine operates by injecting liquid fuel directly in a combustion chamber, and mixing the fuel with recirculated exhaust and fresh air through an auto ignition condition of the fuel. The engine includes at least one turbocharger for extracting energy from the engine exhaust and using that energy to boost intake pressure of recirculated exhaust gas and fresh air. Elevated proportions of exhaust gas recirculated to the engine are attained by throttling the fresh air inlet supply. These elevated exhaust gas recirculation rates allow the HCCI engine to be operated at higher speeds and loads rendering the HCCI engine a more viable alternative to a conventional diesel engine.

  19. Preoperational test report, recirculation ventilation systems

    SciTech Connect

    Clifton, F.T.

    1997-11-11

    This represents a preoperational test report for Recirculation Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides vapor space cooling of tanks AY1O1, AY102, AZ1O1, AZ102 and supports the ability to exhaust air from each tank. Each system consists of a valved piping loop, a fan, condenser, and moisture separator; equipment is located inside each respective tank farm in its own hardened building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  20. In-tank recirculating arsenic treatment system

    DOEpatents

    Brady, Patrick V.; Dwyer, Brian P.; Krumhansl, James L.; Chwirka, Joseph D.

    2009-04-07

    A low-cost, water treatment system and method for reducing arsenic contamination in small community water storage tanks. Arsenic is removed by using a submersible pump, sitting at the bottom of the tank, which continuously recirculates (at a low flow rate) arsenic-contaminated water through an attached and enclosed filter bed containing arsenic-sorbing media. The pump and treatment column can be either placed inside the tank (In-Tank) by manually-lowering through an access hole, or attached to the outside of the tank (Out-of-Tank), for easy replacement of the sorption media.

  1. Remaining Sites Verification Package for the 120-B-1, 105-B Battery Acid Sump, Waste Site Reclassification Form 2006-057

    SciTech Connect

    L. M. Dittmer

    2006-09-25

    The 120-B-1 waste site, located in the 100-BC-1 Operable Unit of the Hanford Site, consisted of a concrete battery acid sump that was used from 1944 to 1969 to neutralize the spent sulfuric acid from lead cell batteries of emergency power packs and the emergency lighting system. The battery acid sump was associated with the 105-B Reactor Building and was located adjacent to the building's northwest corner. The results of verification sampling demonstrated that residual contaminant concentrations do not preclude any future uses and allow for unrestricted use of shallow zone soils. The results also showed that residual contaminant concentrations are protective of groundwater and the Columbia River.

  2. Recirculating Planar Magnetron Modeling and Experiments

    NASA Astrophysics Data System (ADS)

    Franzi, Matthew; Gilgenbach, Ronald; Hoff, Brad; French, Dave; Lau, Y. Y.

    2011-10-01

    We present simulations and initial experimental results of a new class of crossed field device: Recirculating Planar Magnetrons (RPM). Two geometries of RPM are being explored: 1) Dual planar-magnetrons connected by a recirculating section with axial magnetic field and transverse electric field, and 2) Planar cathode and anode-cavity rings with radial magnetic field and axial electric field. These RPMs have numerous advantages for high power microwave generation by virtue of larger area cathodes and anodes. The axial B-field RPM can be configured in either the conventional or inverted (faster startup) configuration. Two and three-dimensional EM PIC simulations show rapid electron spoke formation and microwave oscillation in pi-mode. Smoothbore prototype axial-B RPM experiments are underway using the MELBA accelerator at parameters of -300 kV, 1-20 kA and pulselengths of 0.5-1 microsecond. Implementation and operation of the first RPM slow wave structure, operating at 1GHz, will be discussed. Research supported by AFOSR, AFRL, L-3 Communications, and Northrop Grumman. Done...processed 1830 records...17:52:57 Beginning APS data extraction...17:52:57

  3. High speed exhaust gas recirculation valve

    DOEpatents

    Fensom, Rod; Kidder, David J.

    2005-01-18

    In order to minimize pollutants such as Nox, internal combustion engines typically include an exhaust gas recirculation (EGR) valve that can be used to redirect a portion of exhaust gases to an intake conduit, such as an intake manifold, so that the redirected exhaust gases will be recycled. It is desirable to have an EGR valve with fast-acting capabilities, and it is also desirable to have the EGR valve take up as little space as possible. An exhaust gas recirculation valve is provided that includes an exhaust passage tube, a valve element pivotally mounted within the exhaust passage tube, a linear actuator; and a gear train. The gear train includes a rack gear operatively connected to the linear actuator, and at least one rotatable gear meshing with the rack gear and operatively connected to the valve element to cause rotation of the valve element upon actuation of the linear actuator. The apparatus provides a highly compact package having a high-speed valve actuation capability.

  4. Energy stability in recirculating, energy-recovering linacs

    SciTech Connect

    Merminga, L.; Bisognano, J.J.; Delayen, J.R.

    1996-07-01

    Recirculating, energy-recovering linacs can be used as driver accelerators for high power FELs. Instabilities which arise from fluctuations of the cavity fields are investigated. Energy changes can cause beam loss on apertures, or, when coupled to M{sub 56}, phase oscillations. Both effects change the beam induced voltage in the cavities and can lead to unstable variations of the accelerating field. Stability analysis for small perturbations from equilibrium is performed and threshold currents are determined. Furthermore, the analytical model is extended to include amplitude and phase feedback, with the transfer function in the feedback path presently modeled as a low-pass filter. The feedback gain and bandwidth required for stability are calculated for the high power UV FEL proposed for construction at CEBAF. 4 refs.

  5. Microbial diversity of biological filters in recirculating aquaculture systems.

    PubMed

    Schreier, Harold J; Mirzoyan, Natella; Saito, Keiko

    2010-06-01

    Development of environmentally sustainable farming of marine and freshwater species using recirculating aquaculture systems (RASs) requires a complete understanding of the biological component involved in wastewater treatment. This component integrates biofilters composed of microbial communities whose structure, dynamics, and activities are responsible for system success. Engineering highly efficient, environmentally sound, disease-free, and economically viable systems necessitates a thorough knowledge of microbial processes involved in all facets of RAS biofilters and has only recently been the focus of comprehensive studies. These studies have included the application of molecular tools to characterize community diversity and have identified key processes useful for improving system performance. In this paper we summarize the current understanding of the microbial diversity and physiology of RAS biofilters and discuss directions for future studies. PMID:20371171

  6. RECENT PROGRESS TOWARD A MUON RECIRCULATING LINEAR ACCELERATOR

    SciTech Connect

    Slawomir Bogacz, Vasiliy Morozov, Yves Roblin, Kevin Beard

    2012-07-01

    Both Neutrino Factories (NF) and Muon Colliders (MC) require very rapid acceleration due to the short lifetime of muons. After a capture and bunching section, a linac raises the energy to about 900 MeV, and is followed by one or more Recirculating Linear Accelerators (RLA), possibly followed by a Rapid Cycling Synchnotron (RCS) or Fixed-Field Alternating Gradient (FFAG) ring. A RLA reuses the expensive RF linac section for a number of passes at the price of having to deal with different energies within the same linac. Various techniques including pulsed focusing quadruopoles, beta frequency beating, and multipass arcs have been investigated via simulations to improve the performance and reduce the cost of such RLAs.

  7. Maximizing Number of Passes in Recirculating Energy Recovery Linacs

    NASA Astrophysics Data System (ADS)

    Bogacz, S. Alex

    2016-03-01

    The next generation of high energy recirculating linear accelerators (RLAs) will rely on the energy recovery (ER) process for their extreme high current operation. Here, we discuss optimum design of multi-pass linac optics for an RLA based on a large scale superconducting linac. Initial strategy used in the design of 60 GeV, 6 pass RLA for the LHeC, has been extended to 10 passes for the proposed CEBAF ER experiment. The presented optimization scheme addresses overall beam transport performance, as well as specific beam dynamics issues, such as, beam stability due to collective effects. Work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.

  8. Multi-point optimization of recirculation flow type casing treatment in centrifugal compressors

    NASA Astrophysics Data System (ADS)

    Tun, Min Thaw; Sakaguchi, Daisaku

    2016-06-01

    High-pressure ratio and wide operating range are highly required for a turbocharger in diesel engines. A recirculation flow type casing treatment is effective for flow range enhancement of centrifugal compressors. Two ring grooves on a suction pipe and a shroud casing wall are connected by means of an annular passage and stable recirculation flow is formed at small flow rates from the downstream groove toward the upstream groove through the annular bypass. The shape of baseline recirculation flow type casing is modified and optimized by using a multi-point optimization code with a metamodel assisted evolutionary algorithm embedding a commercial CFD code CFX from ANSYS. The numerical optimization results give the optimized design of casing with improving adiabatic efficiency in wide operating flow rate range. Sensitivity analysis of design parameters as a function of efficiency has been performed. It is found that the optimized casing design provides optimized recirculation flow rate, in which an increment of entropy rise is minimized at grooves and passages of the rotating impeller.

  9. The benefits of powdered activated carbon recirculation for micropollutant removal in advanced wastewater treatment.

    PubMed

    Meinel, F; Zietzschmann, F; Ruhl, A S; Sperlich, A; Jekel, M

    2016-03-15

    PAC adsorption is a widespread option for the removal of organic micropollutants (OMP) from secondary effluent. For an optimal exploitation of the adsorption capacity, PAC recirculation is nowadays a common practice, although the mechanistic interrelations of the complex recirculation process are not fully resolved. In this work, extensive multi-stage batch adsorption testing with repeated PAC and coagulant dosage was performed to evaluate the continuous-flow recirculation system. Partly loaded PAC showed a distinct amount of remaining capacity, as OMP and DOC removals considerably increased with each additional adsorption stage. At a low PAC dose of 10 mg PAC L(-1), removals of benzotriazole and carbamazepine were shown to rise from <40% in the first stage up to >80% in the 11th stage at 30 min adsorption time per stage. At a high PAC dose of 30 mg PAC L(-1), OMP and DOC removals were significantly higher and reached 98% (for benzotriazole and carbamazepine) after 11 stages. Coagulant dosage showed no influence on OMP removal, whereas a major part of DOC removal can be attributed to coagulation. Multi-stage adsorption is particularly beneficial for small PAC doses and significant PAC savings are feasible. A new model approach for predicting multi-stage OMP adsorption on the basis of a single-stage adsorption experiment was developed. It proved to predict OMP removals and PAC loadings accurately and thus contributes towards understanding the PAC recirculation process. PMID:26773491

  10. Inshore recirculating systems for the production of marine finfish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recirculating aquaculture systems (RAS) for both commercial and experimental uses have been developing for decades in many parts of the world. There are several driving forces behind the implementation of recirculating technology for aquaculture production systems. The availability of good and stab...

  11. Energy conservation by partial recirculation of peanut drying air

    SciTech Connect

    Young, J.H.

    1983-06-01

    Conventional, recirculating, and intermittent type peanut dryers were compared in a three-year study. Comparisons indicate that partial recirculation of peanut drying air may reduce energy consumption per unit of water removed by approximately 25% while also reducing required drying time and maintaining high quality.

  12. Energy savings from air recirculation in peanut curing

    SciTech Connect

    Cook, D.F.; Cundiff, J.S.; Vaughan, D.H.

    1982-12-01

    A thin-layer peanut drying simulation model was adapted to incorporate air recirculation. Laboratory crop dryers were designed and constructed to conduct experiments to verify the model. Five batches of peanuts were dried using different recirculation strategies. The model successfully predicted the results.

  13. Sensitivity of bandpass filters using recirculating delay-line structures

    NASA Astrophysics Data System (ADS)

    Heyde, Eric C.

    1996-12-01

    Recirculating delay lines have value notably as sensors and optical signal processors. Most useful applications depend on a high-finesse response from a network. A proof that, with given response parameters, more complex systems can produce behavior that is more stable to the effects of nonidealities than a single recirculating loop is presented.

  14. 21 CFR 880.5045 - Medical recirculating air cleaner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Medical recirculating air cleaner. 880.5045... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices § 880.5045 Medical recirculating air cleaner. (a) Identification. A medical...

  15. 21 CFR 880.5045 - Medical recirculating air cleaner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Medical recirculating air cleaner. 880.5045... (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices § 880.5045 Medical recirculating air cleaner. (a) Identification. A medical...

  16. 40 CFR 1065.127 - Exhaust gas recirculation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Exhaust gas recirculation. 1065.127 Section 1065.127 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.127 Exhaust gas recirculation. Use...

  17. 40 CFR 1065.127 - Exhaust gas recirculation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Exhaust gas recirculation. 1065.127 Section 1065.127 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.127 Exhaust gas recirculation. Use...

  18. 40 CFR 1065.127 - Exhaust gas recirculation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Exhaust gas recirculation. 1065.127 Section 1065.127 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.127 Exhaust gas recirculation. Use...

  19. 40 CFR 1065.127 - Exhaust gas recirculation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Exhaust gas recirculation. 1065.127 Section 1065.127 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.127 Exhaust gas recirculation. Use...

  20. 40 CFR 1065.127 - Exhaust gas recirculation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Exhaust gas recirculation. 1065.127 Section 1065.127 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Equipment Specifications § 1065.127 Exhaust gas recirculation. Use...

  1. Recirculation bubbler for glass melter apparatus

    DOEpatents

    Guerrero, Hector; Bickford, Dennis

    2007-06-05

    A gas bubbler device provides enhanced recirculation of molten glass within a glass melter apparatus. The bubbler device includes a tube member disposed within a pool of molten glass contained in the melter. The tube member includes a lower opening through which the molten glass enters and upper slots disposed close to (above or below) the upper surface of the pool of molten glass and from which the glass exits. A gas (air) line is disposed within the tube member and extends longitudinally thereof. A gas bubble distribution device, which is located adjacent to the lower end of the tube member and is connected to the lower end of the gas line, releases gas through openings therein so as to produce gas bubbles of a desired size in the molten glass and in a distributed pattern across the tube member.

  2. Recirculating Linac Accelerators For Future Muon Facilities

    SciTech Connect

    Yves Roblin, Alex Bogacz, Vasiliy Morozov, Kevin Beard

    2012-04-01

    Neutrino Factories (NF) and Muon Colliders (MC) require rapid acceleration of shortlived muons to multi-GeV and TeV energies. A Recirculating Linear Accelerator (RLA) that uses superconducting RF structures can provide exceptionally fast and economical acceleration to the extent that the focusing range of the RLA quadrupoles allows each muon to pass several times through each high-gradient cavity. A new concept of rapidly changing the strength of the RLA focusing quadrupoles as the muons gain energy is being developed to increase the number of passes that each muon will make in the RF cavities, leading to greater cost effectiveness. We discuss the optics and technical requirements for RLA designs, using RF cavities capable of simultaneous acceleration of both m+ and m- species. The design will include the optics for the multi-pass linac and droplet-shaped return arcs.

  3. Recirculating Molten Metal Supply System And Method

    DOEpatents

    Kinosz, Michael J.; Meyer, Thomas N.

    2003-07-01

    The melter furnace includes a heating chamber (16), a pump chamber (18), a degassing chamber (20), and a filter chamber (22). The pump chamber (18) is located adjacent the heating chamber (16) and houses a molten metal pump (30). The degassing chamber (20) is located adjacent and in fluid communication with the pump chamber (18), and houses a degassing mechanism (36). The filter chamber (22) is located adjacent and in fluid communication with the degassing chamber (20). The filter chamber (22) includes a molten metal filter (38). The melter furnace (12) is used to supply molten metal to an externally located holder furnace (14), which then recirculates molten metal back to the melter furnace (12).

  4. Nutrient Management in Recirculating Hydroponic Culture

    NASA Technical Reports Server (NTRS)

    Bugbee, Bruce

    2004-01-01

    There is an increasing need to recirculate and reuse nutrient solutions in order to reduce environmental and economic costs. However, one of the weakest points in hydroponics is the lack of information on managing the nutrient solution. Many growers and research scientists dump out nutrient solutions and refill at weekly intervals. Other authors have recommended measuring the concentrations of individual nutrients in solution as a key to nutrient control and maintenance. Dumping and replacing solution is unnecessary. Monitoring ions in solution is not always necessary; in fact the rapid depletion of some nutrients often causes people to add toxic amounts of nutrients to the solution. Monitoring ions in solution is interesting, but it is not the key to effective maintenance.

  5. Recirculating planar magnetrons: simulations and experiment

    SciTech Connect

    Franzi, Matthew; Gilgenbach, Ronald; French, David; Lau, Y.Y.; Simon, David; Hoff, Brad; Luginsland, John W.

    2011-07-01

    The Recirculating Planar Magnetron (RPM) is a novel crossed-field device whose geometry is expected to reduce thermal load, enhance current yield as well as ease the geometric limitations in scaling to high RF frequencies as compared to the conventional cylindrical magnetrons. The RPM has two different adaptations: A. Axial B field and radial E field; B. Radial B field and axial E field. The preliminary configuration (A) to be used in experiments at the University of Michigan consists of two parallel planar sections which join on either end by cylindrical regions to form a concentric extruded ellipse. Similar to conventional magnetrons, a voltage across the AK gap in conjunction with an axial magnetic field provides the electrons with an ExB drift. The device is named RPM because the drifting electrons recirculate from one planar region to the other. The drifting electrons interact with the resonantly tuned slow wave structure on the anode causing spoke formation. These electron spokes drive a RF electric field in the cavities from which RF power may be extracted to Waveguides. The RPM may be designed in either a conventional configuration with the anode on the outside, for simplified extraction, or as an inverted magnetron with the anode at the inner conductor, for fast start-up. Currently, experiments at the Pulsed Power and Microwave Laboratory at the University of Michigan are in the setup and design phase. A conventional RPM with planar cavities is to be installed on the Michigan Electron Long Beam Accelerator (MELBA) and is anticipated to operate at -200kV, 0.2T with a beam current of 1-10 kA at 1GHz. The conventional RPM consists of 12 identical planar cavities, 6 on each planar side, with simulated quality factor of 20.

  6. Capture Zone Analyses of Two Airlift Recirculation Wells in the Southern Sector of A/M Area

    SciTech Connect

    Aleman, S.E.

    1999-09-14

    This report documents a series of capture zone analyses performed to access the expected overall performance of two (of the twelve) vertical airlift recirculation wells (ARWs) (specifically, SSR-011 and SRR-012) located in the Southern Sector of A/M Area.

  7. Exhaust gas recirculation method for internal combustion engines

    SciTech Connect

    Kawanabe, T.; Kimura, K.; Asakura, M.; Shiina, T.

    1988-07-19

    This patent describes a method of controlling exhaust gas recirculation in an internal combustion engine having an exhaust passage, an intake passage, an exhaust gas recirculating passage communicating the exhaust passage with the intake passage, and exhaust gas recirculating valve; and a transmission having a shift lever. The valve opening of the exhaust gas recirculating valve is controlled in response to operating conditions of the engine so as to regulate the amount of exhaust gas recirculation to values appropriate to the operating conditions of the engine. The method comprising the steps of (1) determining whether or not the engine is in at least one of a predetermined accelerating condition and a predetermined decelerating condition; (2) varying the valve opening of the exhaust gas recirculating valve by a predetermined value when the engine is determined to be in at least one of the predetermined accelerating condition and the predetermined decelerating condition; (3) detecting a position of the shift lever of the transmission; and (4) correcting the predetermined value in accordance with the detected position of the shift lever so as to increase the valve opening of the exhaust gas recirculating valve as the shift lever of the transmission is set to a higher speed position.

  8. Recirculating induction accelerators for inertial fusion: Prospects and status

    SciTech Connect

    Friedman, A.; Barnard, J.J.; Cable, M.D.

    1995-09-03

    The US is developing the physics and technology of induction accelerators for heavy-ion beam-driven inertial fusion. The recirculating induction accelerator repeatedly passes beams through the same set of accelerating and focusing elements, thereby reducing both the length and gradient of the accelerator structure. This promises an attractive driver cost, if the technical challenges associated with recirculation can be met. Point designs for recirculator drivers were developed in a multi-year study by LLNL, LBNL, and FM Technologies, and that work is briefly reviewed here. To validate major elements of the recirculator concept, we are developing a small (4-5-m diameter) prototype recirculator which will accelerate a space-charge-dominated beam of K{sup +} ions through 15 laps, from 80 to 320 keV and from 2 to 8 mA. Transverse beam confinement is effected via permanent-magnet quadrupoles; bending is via electric dipoles. This ``Small Recirculator`` is being developed in a build-and-test sequence of experiments. An injector, matching section, and linear magnetic channel using seven half-lattice periods of permanent-magnet quadrupole lenses are operational. A prototype recirculator half-lattice period is being fabricated. This paper outlines the research program, and presents initial experimental results.

  9. Recirculating induction accelerators for inertial fusion: Prospects and status

    SciTech Connect

    Friedman, A.; Barnard, J.J.; Cable, M.D.

    1995-11-29

    The U.S. is developing the physics and technology of induction accelerators for heavy-ion beam-driven inertial fusion. The recirculating induction accelerator repeatedly passes beams through the same set of accelerating and focusing elements, thereby reducing both the length and gradient of the accelerator structure. This promises an attractive driver cost, if the technical challenges associated with recirculation can be met. Point designs for recirculator drivers were developed in a multi-year study by LLNL, LBNL, and FM Technologies, and that work is briefly reviewed here. To validate major elements of the recirculator concept, we are developing a small (4.5-m diameter) prototype recirculator which will accelerate a space-charge-dominated beam of K{sup +} ions through 15 laps, from 80 to 320 keV and from 2 to 8 mA. Transverse beam confinement is effected via permanent-magnet quadrupoles; bending is via electric dipoles. This {open_quotes}Small Recirculator{close_quotes} is being developed through a sequence of experiments. An injector, matching section, and linear magnetic channel using seven half-lattice periods of permanent-magnet quadrupole lenses are operational. A prototype recirculator half-lattice period is being fabricated. This paper outlines the research program, and presents initial experimental results.

  10. Design study of a gas turbine combustor with heat recirculation

    NASA Technical Reports Server (NTRS)

    Ganji, A.; Branch, M. C.; Oppenheim, A. K.

    1976-01-01

    A means of avoiding stoichiometric combustion, reducing emissions, and yet providing stable burning for lean mixtures is based on the use of heat recirculation rather than flow recirculation. This paper is concerned with the calculations of the design parameters of a gas turbine combustor with heat exchanger to produce the desired preheat temperature. The combustor inlet temperature, maximum temperature, equivalence ratio and recirculated heat are determined by thermodynamic analysis. The heat transfer analysis then provides the dimensions of the system to produce the predetermined boundary conditions. It is indicated that practical combustor design may be feasible for reactant mixtures as low as equivalence ratio 0.2.

  11. An advanced anaerobic biofilter with effluent recirculation for phenol removal and methane production in treatment of coal gasification wastewater.

    PubMed

    Li, Yajie; Tabassum, Salma; Zhang, Zhenjia

    2016-09-01

    An advanced anaerobic biofilter (AF) was introduced for the treatment of coal gasification wastewater (CGW), and effluent recirculation was adopted to enhance phenol removal and methane production. The results indicated that AF was reliable in treating diluted CGW, while its efficiency and stability were seriously reduced when directly treating raw CGW. However, its performance could be greatly enhanced by effluent recirculation. Under optimal effluent recirculation of 0.5 to the influent, concentrations of chemical oxygen demand (COD) and total phenol in the effluent could reach as low as 234.0 and 14.2mg/L, respectively. Also, the rate of methane production reached 169.0mLCH4/L/day. Though CGW seemed to restrain the growth of anaerobic microorganisms, especially methanogens, the inhibition was temporary and reversible, and anaerobic bacteria presented strong tolerance. The activities of methanogens cultivated in CGW could quickly recover on feeding with glucose wastewater (GW). However, the adaptability of anaerobic bacteria to the CGW was very poor and the activity of methanogens could not be improved by long-term domestication. By analysis using the Haldane model, it was further confirmed that high effluent recirculation could result in high activity for hydrolytic bacteria and substrate affinity for toxic matters, but only suitable effluent recirculation could result in high methanogenic activity. PMID:27593269

  12. Pulsed Magnet Arc Designs for Recirculating Linac Muon Accelerators

    SciTech Connect

    K.B. Beard, R.P. Johnson, S.A. Bogacz, G.M. Wang

    2009-05-01

    Recirculating linear accelerators (RLAs) using both pulsed quadrupoles and pulsed dipoles can be used to quickly accelerate muons in the 3 – 2000 GeV range. Estimates on the requirements for the pulsed quadrupoles and dipoles are presented.

  13. 33 CFR 159.127 - Safety coliform count: Recirculating devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... recirculating device must have less than 240 fecal coliform bacteria per 100 milliliters. These samples must be collected in accordance with § 159.123(b) and tested in accordance with 40 CFR Part 136....

  14. 33 CFR 159.127 - Safety coliform count: Recirculating devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... recirculating device must have less than 240 fecal coliform bacteria per 100 milliliters. These samples must be collected in accordance with § 159.123(b) and tested in accordance with 40 CFR part 136....

  15. 33 CFR 159.127 - Safety coliform count: Recirculating devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... recirculating device must have less than 240 fecal coliform bacteria per 100 milliliters. These samples must be collected in accordance with § 159.123(b) and tested in accordance with 40 CFR Part 136....

  16. 33 CFR 159.127 - Safety coliform count: Recirculating devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... recirculating device must have less than 240 fecal coliform bacteria per 100 milliliters. These samples must be collected in accordance with § 159.123(b) and tested in accordance with 40 CFR Part 136....

  17. 33 CFR 159.127 - Safety coliform count: Recirculating devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... recirculating device must have less than 240 fecal coliform bacteria per 100 milliliters. These samples must be collected in accordance with § 159.123(b) and tested in accordance with 40 CFR Part 136....

  18. Eddy-driven recirculation of Atlantic Water in Fram Strait

    NASA Astrophysics Data System (ADS)

    Hattermann, Tore; Isachsen, Pâl. Erik; Appen, Wilken-Jon; Albretsen, Jon; Sundfjord, Arild

    2016-04-01

    Eddy-resolving regional ocean model results in conjunction with synthetic float trajectories and observations provide new insights into the recirculation of the Atlantic Water (AW) in Fram Strait that significantly impacts the redistribution of oceanic heat between the Nordic Seas and the Arctic Ocean. The simulations confirm the existence of a cyclonic gyre around the Molloy Hole near 80°N, suggesting that most of the AW within the West Spitsbergen Current recirculates there, while colder AW recirculates in a westward mean flow south of 79°N that primarily relates to the eastern rim of the Greenland Sea Gyre. The fraction of waters recirculating in the northern branch roughly doubles during winter, coinciding with a seasonal increase of eddy activity along the Yermak Plateau slope that also facilitates subduction of AW beneath the ice edge in this area.

  19. Development of a hybrid k-epsilon turbulence model for swirling recirculating flows under moderate to strong swirl intensities

    NASA Astrophysics Data System (ADS)

    Chang, Keh-Chin; Chen, Ching-Shun

    1993-03-01

    A hybrid k-epsilon turbulence model, based on the concept that the modification of anisotropic effects should not be made in the flow regions inherent to small streamline curvatures, has been developed and examined with the swirling recirculating flows, with the swirl levels ranging from 0.6 to 1.23 in an abrupt pipe expansion. A fairly satisfactory agreement of model predictions with the experimental data shows that this hybrid k-epsilon model can perform better simulation of swirling recirculating flows as compared to the standard k-epsilon model and the modified k-epsilon model proposed by Abujelala and Lilley (1984).

  20. Recirculation of the Canary Current in Fall

    NASA Astrophysics Data System (ADS)

    Hernandez-Guerra, A.; Espino-Falcón, E.; Vélez-Belchí, P.; Pérez-Hernández, M. D.; Martínez, A.; Cana, L.

    2015-12-01

    CTD and LADCP data measured in October 2014 are used to describe water masses, geostrophic circulation and mass transport in the Eastern Boundary of the North Atlantic Subtropical Gyre. Initial geostrophic velocities are adjusted to velocities from the LADCP data to estimate an initial velocity at the reference layer. Final reference velocities and consequently circulation is estimated from an inverse box model applied to an ocean divided into 12 neutral density layers. This allows us to evaluate mass fluxes consistent with the thermal wind equation and mass conservation. Ekman transport derived from the Weather Research and Forecasting (WRF) model is added to the first layer and adjusted with the inverse model. The Canary Current (CC) transports southward a net mass of 3.8±0.7 Sv (1 Sv=106 m3/s≈109 kg/s) of North Atlantic Central Water (NACW) at the thermocline layers (~0-700 m) and 1.9±0.6 Sv of a mixture of Mediterranean Water (MW) and Antarctic Intermediate Water (AAIW) at intermediate layers (~800-1400 m). The CC recirculates northward at a rate of 4.8±0.8 Sv at the thermocline layers between the Lanzarote Island and the African coast (Lanzarote Passage) on this occasion. Separately, at intermediate layers, AAIW flows northward at a rate of 2.4±0.6 Sv through the Lanzarote Passage transported by the Intermediate Poleward Undercurrent (IPUC).

  1. A closed recirculated sea-water system

    USGS Publications Warehouse

    1967-01-01

    Study of a virus disease in the chinook salmon (Oncorhynchus tshawytscha) necessitated the use of a marine environment to study the long range effects of the disease and to complete the life cycle of its etiologic agent. A closed recirculated sea-water system was designed for use under experimental laboratory conditions so that controlled studies of the disease could be made. As others may wish to do marine environment studies in the laboratory, the design and operation of our system are presented. Other systems currently in use have been described by Chin (1959), DeWitt and Salo (1960), McCrimmon and Berst (1966), and the authors of collected papers edited by Clark and Clark (1964). Preparatory to the design and construction of the system in use in this laboratory, visits were made to marine systems in use at the University of Washington's College of Fisheries, Seattle, -washington, and Friday Harbor Laboratory, San Juan Island, Washington; the Washington State Department of Fisheries' Point whitney Shellfish Laboratory, Brinnon, Washington; Humboldt State College, Arcata, California; and the Steinhart Aquarium of the California Academy of Science, San Francisco, California.

  2. Heat recirculating cooler for fluid stream pollutant removal

    DOEpatents

    Richards, George A.; Berry, David A.

    2008-10-28

    A process by which heat is removed from a reactant fluid to reach the operating temperature of a known pollutant removal method and said heat is recirculated to raise the temperature of the product fluid. The process can be utilized whenever an intermediate step reaction requires a lower reaction temperature than the prior and next steps. The benefits of a heat-recirculating cooler include the ability to use known pollutant removal methods and increased thermal efficiency of the system.

  3. The Impact of Tropical Recirculation on Polar Composition

    NASA Technical Reports Server (NTRS)

    Strahan, S. E.; Schoeberl, M. R.; Steenrod, S. D.

    2009-01-01

    We derive the tropical modal age of air from an analysis of the water vapor tape recorder. We combine the observationally derived modal age with mean age of air from CO2 and SF6 to create diagnostics for the independent evaluation of the vertical transport rate and horizontal recirculation into the tropics between 16-32 km. These diagnostics are applied to two Global Modeling Initiative (GMI) chemistry and transport model (CTM) age tracer simulations to give new insights into the tropical transport characteristics of the meteorological fields from the GEOS4-GCM and the GEOS4-DAS. Both simulations are found to have modal ages that are in reasonable agreement with the empirically derived age (i.e ., transit times) over the entire altitude range. Both simulations show too little horizontal recirculation into the tropics above 22 km, with the GEOS4-DAS fields having greater recirculation. Using CH4 as a proxy for mean age, comparisons between HALOE and model CH4 in the Antarctic demonstrate how the strength of tropical recirculation affects polar composition in both CTM experiments. Better tropical recirculation tends to improve the CH4 simulation in the Antarctic. However, mean age in the Antarctic lower stratosphere can be compromised by poor representation of tropical ascent, tropical recirculation, or vortex barrier strength. The connection between polar and tropical composition shown in this study demonstrates the importance of diagnosing each of these processes separately in order to verify the adequate representation of the processes contributing to polar composition in models.

  4. Exhaust gas recirculation system for internal combustion engine

    SciTech Connect

    Yoshioka, S.; Nomoto, Y.; Oda, T.; Yokooku, K.

    1984-09-18

    An internal combustion engine is provided with an exhaust gas recirculating passage for communicating the intake passage and the exhaust passage thereof. The recirculating passage is provided with a valve for controlling the amount of recirculated exhaust gas. A fundamental air-fuel ratio control value for regulating the air-fuel ratio of the intake gas to a predetermined value is corrected by an operating condition correction value according to the operating condition of the engine. The operating condition correction value is successively changed to an optimal value by comparing the actually obtained air-fuel ratio with a predetermined value. The operating condition correction value for correcting the fundamental air-fuel ratio control value when the exhaust gas recirculation is carried out is changed independently from the same for correcting the fundamental air-fuel ratio correction value when the exhaust gas recirculation is not carried out. The initial values of the former correction value and the latter correction value are compared with each other, while the present values of the former correction value and the latter correction value are compared with each other. The comparison value of the initial values and the comparison value of the present values are compared with each other to detect clogging of the recirculating passage. When clogging is detected, the valve is controlled to compensate for the clogging.

  5. A block-corrected subdomain solution procedure for recirculating flow calculations

    NASA Technical Reports Server (NTRS)

    Braaten, M. E.; Patankar, S. V.

    1989-01-01

    This paper describes a robust and efficient subdomain solution procedure for two-dimensional recirculating flows. The solution domain is divided into a number of overlapping subdomains, and a direct fully coupled solution is obtained for each subdomain using a sparse matrix form of LU decomposition. An effective parabolic block correction procedure, which calculates global corrections to the tentative solution by a marching technique similar to that used for boundary layer flows, is used to accelerate the convergence of the basic procedure. The use of effective block correction is found to be essential for the success of the subdomain approach on strongly recirculating flows. In a number of laminar two-dimensional flows, the new block-corrected method performed extremely well, rivaling the best direct methods in execution time, while requiring substantially less computer storage. The new method proved to be from two to ten times faster than conventional iterative methods, while requiring only a moderate increase in storage.

  6. Thermal characterization of an AMTEC recirculating test cell. [Alkali Metal ThermoElectric Converter

    NASA Technical Reports Server (NTRS)

    Underwood, M. L.; O'Connor, D.; Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.; Bankston, C. P.

    1990-01-01

    An alkali metal thermoelectric converter (AMTEC) recirculating test cell has been operated in order to determine the magnitudes of the primary heat losses of the cell and the value of the emissivity of the condenser surface. The energy balance included radiation losses, conductive losses, and losses due to the flow of sodium into the cell. The radiative heat flux dominated the heat loss mechanism of the cell at open circuit, and the condenser emissivity was calculated to be about 0.1. It is shown that, if this emissivity can be reduced to 0.02, then parasitic losses in an AMTEC recirculating test cell operating near peak power would be less than 40 percent of the heat required by the cell. The condenser emissivity decreases with elapsed time, resulting in improved thermal performance of the cell.

  7. Analysis of a heat recirculating cooler for fuel gas sulfur removal in solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Richards, Geo. A.; Berry, David A.; Freed, Adam

    When using conventional fossil fuels, most fuel cell systems require sulfur removal as part of their fuel processing. A novel approach to enable conventional sulfur removal in high-temperature fuel processing is presented. Using established principles from heat-recirculating combustors, it is suggested that high-temperature syngas can be momentarily cooled to conditions that would permit conventional sulfur removal to be carried out at relatively low temperatures. The recirculated heat is then used to heat the gas back to conditions that are minimally less than the original temperature. A model for evaluating the performance of this concept is presented, and calculations suggest that relative to fuel cell applications, reasonable physical dimensions can be expected in actual applications. For high-pressure syngas (i.e., coal gasification), the physical dimensions will rise with the operating pressure.

  8. CFB combustor with internal solids recirculation -- Pilot testing and design applications

    SciTech Connect

    Belin, F.; Maryamchik, M.; Fuller, T.A.; Perna, M.A.

    1995-12-31

    The new generation of B and W`s CFB boilers with entirely internal recirculation of solids collected by the primary impact separator is uniquely compact and features a simple, low-maintenance solids collection system. Thorough testing of the new concept at the Cold CFB Model and the 2.5 MWth Pilot CFB combustor confirmed its effective performance equal to that of a CFB unit with external solids recirculation from the primary separator. While providing overall advantages of compactness and simplicity, the new design is especially valuable for repowering of the existing power plants where B and W`s CFB boiler fits into the plan area of PC-fired boilers.

  9. Efficiency of an AMTEC recirculating test cell, experiments and projections

    SciTech Connect

    Underwood, M.L.; O`Connor, D.; Williams, R.M.; Jeffries-Nakamura, B.; Ryan, M.A.

    1992-05-01

    The alkali metal thermal to electric converter (AMTEC) is an electrochemical device for the direct conversion of heat to electrical energy with efficiencies potentially near Carnot. The future usefulness of AMTEC for space power conversion depends on the efficiency of the devices. Systems studies have projected from 15% to 35% thermal to electric conversion efficiencies, and one experiment has demonstrated 19% efficiency for a short period of time. Recent experiments in a recirculating test cell (RTC) have demonstrated sustained conversion efficiencies as high as 10.2% early in cell life and 9.7% after maturity. Extensive thermal and electrochemical analysis of the cell during several experiments demonstrated that the efficiency could be improved in two ways. First, the electrode performance could be improved. The electrode for these tests operated at about one third the power density of state of the art electrodes. The low power density was caused by a combination of high series resistance and high mass flow resistance. Reducing these resistances could improve the efficiency to greater than 10%. Second, the cell thermal performance could be improved. Efficiencies greater than 14% could be realized through reducing the radiative thermal loss. Further improvements to the efficiency range predicted by systems studies can be accomplished through the development and use of an advanced condenser with improved reflectivity, close to that of a smooth sodium film, and the series connecting of individual cells to further reduce thermal losses.

  10. Oil content of sediments in the sump of a salt dome solution-mined cavern used for crude oil storage. Final report

    SciTech Connect

    Niederhoff, P.; Giles, H.N.

    1981-09-01

    The studies reported herein were conducted to ascertain if petroleum hydrocarbons are likely to accumulate in the sump sediments of a salt dome solution cavern used for crude oil storage and, if so, which hydrocarbons and in what concentrations. Cavern K 117 at Etzel, West Germany was selected for sampling because considerable data were available pertaining to the cavern and its crude oil inventory as a result of earlier studies. Mineralogical analyses of the sump samples revealed that they predominantly consist of uncemented halite crystals, ranging up to several centimeters in length, with subordinate anhydrite, and traces of gypsum and clay. Some of the mineral particles are colorless and translucent, while others are noticeably contaminated with oil. The samples exuded a distinct petroleum odor. Gas chromatographic analysis of an evolved gas sample showed the presence of the normal-paraffins propane through octane. Gas chromatographic analyses of a solvent extract of the sediment showed hydrocarbon and sulfur-compound distributions typical of crude oil. An infrared spectrum of the extract was also characteristic of a weathered or topped crude oil. The hydrocarbon content of the sediment samples was determined to be 780 ppM on the basis of a tetrachloromethane extract. It is believed that the petroleum present in the sump sediments principally results from cavern workover operations involving the pulling and resetting of the brine tubing string. When the brine string is reset it fills with oil because a packer is not used. To displace this oil, river water is pumped down the tubing at a moderately high rate. During this flushing process, clay particles dispersed in the river water adsorb a film of oil. As the oil-filmed clay particles enter the brine in the cavern they electrolytically flocculate and oil is sedimented to the cavern sump.

  11. Bio-desulfurization of biogas using acidic biotrickling filter with dissolved oxygen in step feed recirculation.

    PubMed

    Chaiprapat, Sumate; Charnnok, Boonya; Kantachote, Duangporn; Sung, Shihwu

    2015-03-01

    Triple stage and single stage biotrickling filters (T-BTF and S-BTF) were operated with oxygenated liquid recirculation to enhance bio-desulfurization of biogas. Empty bed retention time (EBRT 100-180 s) and liquid recirculation velocity (q 2.4-7.1 m/h) were applied. H2S removal and sulfuric acid recovery increased with higher EBRT and q. But the highest q at 7.1 m/h induced large amount of liquid through the media, causing a reduction in bed porosity in S-BTF and H2S removal. Equivalent performance of S-BTF and T-BTF was obtained under the lowest loading of 165 gH2S/m(3)/h. In the subsequent continuous operation test, it was found that T-BTF could maintain higher H2S elimination capacity and removal efficiency at 175.6±41.6 gH2S/m(3)/h and 89.0±6.8% versus S-BTF at 159.9±42.8 gH2S/m(3)/h and 80.1±10.2%, respectively. Finally, the relationship between outlet concentration and bed height was modeled. Step feeding of oxygenated liquid recirculation in multiple stages clearly demonstrated an advantage for sulfide oxidation. PMID:25569031

  12. Recirculating photonic filter: a wavelength-selective time delay for optically controlled phased-array antenna

    NASA Astrophysics Data System (ADS)

    Yegnanarayanan, Siva; Trinh, Paul D.; Jalali, Bahram

    1996-11-01

    A wavelength-selective photonic time delay filter is proposed and demonstrated. The device consists of an optical phased-array waveguide grating in a recirculating feedback configuration. It can function as a true-time-delay generator for squint-free beam steering in optically- controlled phased-array antennas. As the photonic filter uses the optical carrier wavelength to select the desired time delay, a one-to-one map is established between the optical carrier wavelength and the desired antenna direction, thus eliminating complex switching networks required to select the appropriate delay line. The proposed device can also function as the encoder/decoder in wavelength-CDMA. The concept uses a waveguide prism in a symmetric feedback (recirculating) configuration. The modulated optical carrier is steered by the waveguide prism to the appropriate integrated delay line depending on the carrier wavelength. The signal is delayed and is fed back into the symmetric input port. The prism then focuses the delayed beam into the common output port. Thus three sequential operations are performed: (1) wavelength demultiplexing, (2) time delay, and (3) wavelength multiplexing. It is important to note that the recirculating photonic filter has no 1/N loss; all the power at a given wavelength is diffracted into the output port. Furthermore, high resolution (6 - 8 bits) can be obtained in a compact integrated device. A prototype regular recirculating photonic filter true-time delay device was realized using a 8-channel arrayed-waveguide grating demultiplexer and external (off-chip) fiber delay lines. The grating was fabricated in the silica waveguide technology with 0.8 nm channel spacing (FSR equals 6.4 nm) and operating in the 1.5 micrometers wavelength range. Light from an external cavity tunable laser was rf modulated at 10 - 40 MHz and was coupled into the arrayed waveguide grating chip and time/phase measurements were performed sing a digital oscilloscope. Feedback delay

  13. Acceleration schedules for a recirculating heavy-ion accelerator

    SciTech Connect

    Sharp, W.M.; Grote, D.P.

    2002-05-01

    Recent advances in solid-state switches have made it feasible to design programmable, high-repetition-rate pulsers for induction accelerators. These switches could lower the cost of recirculating induction accelerators, such as the ''small recirculator'' at Lawrence Livermore National Laboratory (LLNL), by substantially reducing the number of induction modules. Numerical work is reported here to determine what effects the use of fewer pulsers at higher voltage would have on the beam quality of the LLNL small recirculator. Lattices with different numbers of pulsers are examined using the fluid/envelope code CIRCE, and several schedules for acceleration and compression are compared for each configuration. For selected schedules, the phase-space dynamics is also studied using the particle-in-cell code WARP3d.

  14. Boosting devices with integral features for recirculating exhaust gas

    SciTech Connect

    Wu, Ko-Jen

    2015-12-22

    According to one embodiment of the invention, a turbine housing includes a turbine inlet in fluid communication with a turbine volute configured to house a turbine wheel, the turbine inlet configured to direct an exhaust gas flow from an engine to the turbine wheel. The turbine housing also includes a turbine outlet in fluid communication with the turbine volute, the turbine outlet configured to direct the exhaust gas flow to an exhaust gas conduit and a first exhaust gas recirculation supply port located on and in fluid communication with the turbine outlet, the first exhaust gas recirculation supply port being configured to direct a portion of the exhaust gas flow to an exhaust gas recirculation supply conduit.

  15. Hydrothermal carbonization: process water characterization and effects of water recirculation.

    PubMed

    Stemann, Jan; Putschew, Anke; Ziegler, Felix

    2013-09-01

    Poplar wood chips were treated hydrothermally and the increase of process efficiency by water recirculation was examined. About 15% of the carbon in the biomass was dissolved in the liquid phase when biomass was treated in de-ionized water at 220 °C for 4 h. The dissolved organic matter contained oxygen and was partly aerobically biodegradable. About 30-50% of the total organic carbon originated from organic acids. A polar and aromatic fraction was extracted and a major portion of the organic load was of higher molecular weight. By process water recirculation organic acids in the liquid phase concentrated and catalyzed dehydration reactions. As a consequence, functional groups in hydrothermally synthesized coal declined and dewaterability was enhanced. Recirculated reactive substances polymerized and formed additional solid substance. As a result, carbon and energetic yields of the produced coal rose to 84% and 82%, respectively. PMID:23792664

  16. Boosting devices with integral features for recirculating exhaust gas

    DOEpatents

    Wu, Ko -Jen

    2015-09-15

    According to one embodiment of the invention, a compressor housing includes a compressor inlet in fluid communication with a compressor volute configured to house a compressor wheel, the compressor inlet configured to provide a first air flow to the compressor wheel and a compressor outlet in fluid communication with the compressor volute, the compressor outlet configured to direct a compressed gas to an intake manifold. The compressor housing further includes an exhaust gas recirculation inlet port in fluid communication with the compressor volute, the exhaust gas recirculation inlet port being configured to combine an exhaust gas flow with the air flow to the compressor wheel.

  17. Design and Evaluation of a Water Recirculation Loop Maintenance Device for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  18. Design and Evaluation of a Water Recirculation Loop Maintenance Device for the Advanced Spacesuit Water Membrane Evaporator

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  19. In-tank aeration, a necessary compliment of loaded systems in an airlift recirculating aquaculture system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water treatment components in recirculating aquaculture systems in generally address solids removal, nitrification, circulation, aeration, and degasification. Airlift pumps in a recirculating aquaculture system can address water circulation, aeration, and degasification. Recent data indicates oxygen...

  20. Low-head saltwater recirculating aquaculture systems utilized for juvenile red drum production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recirculating aquaculture systems reuse water with mechanical and biological treatment between each use and thus require wastewater treatment techniques for continuous waste removal. However, the traditional techniques and equipment utilized in recirculating aquaculture systems are expensive. The d...

  1. A Cure for Multipass Beam Breakup in Recirculating Linacs

    SciTech Connect

    Byung C. Yunn

    2004-07-02

    We investigate a method to control the multipass dipole beam breakup instability in a recirculating linac including energy recovery. Effectiveness of an external feedback system for such a goal is shown clearly in a simplified model. We also verify the theoretical result with a simulation study.

  2. A METHOD TO CONTROL MULTIPASS BEAM BREAKUP IN RECIRCULATING LINACS

    SciTech Connect

    Byung Yunn

    2003-05-01

    We investigate a method to control the multipass dipole beam breakup instability in a recirculating linac including energy recovery. Effectiveness of an external feedback system for such a goal is shown clearly in a simplified model. We also verify the theoretical result with a simulation study.

  3. In Situ Biotreatment of TBA with Recirculation/Oxygenation.

    PubMed

    North, Katharine P; Mackay, Douglas M; Kayne, Julian S; Petersen, Daniel; Rasa, Ehsan; Rastegarzadeh, Laleh; Holland, Reef B; Scow, Kate M

    2012-01-01

    The potential for in situ biodegradation of tert-butyl alcohol (TBA) by creation of aerobic conditions in the subsurface with recirculating well pairs was investigated in two field studies conducted at Vandenberg Air Force Base (VAFB). In the first experiment, a single recirculating well pair with bromide tracer and oxygen amendment successfully delivered oxygen to the subsurface for 42 days. TBA concentrations were reduced from approximately 500 μg/L to below the detection limit within the treatment zone and the treated water was detected in a monitoring transect several meters downgradient. In the second experiment, a site-calibrated model was used to design a double recirculating well pair with oxygen amendment, which successfully delivered oxygen to the subsurface for 291 days and also decreased TBA concentrations to below the detection limit. Methylibium petroleiphilum strain PM1, a known TBA-degrading bacterium, was detectable at the study site but addition of oxygen had little impact on the already low baseline population densities, suggesting that there was not enough carbon within the groundwater plume to support significant new growth in the PM1 population. Given favorable hydrogeologic and geochemical conditions, the use of recirculating well pairs to introduce dissolved oxygen into the subsurface is a viable method to stimulate in situ biodegradation of TBA or other aerobically-degradable aquifer contaminants. PMID:23358537

  4. In Situ Biotreatment of TBA with Recirculation/Oxygenation

    PubMed Central

    North, Katharine P.; Mackay, Douglas M.; Kayne, Julian S.; Petersen, Daniel; Rasa, Ehsan; Rastegarzadeh, Laleh; Holland, Reef B.; Scow, Kate M.

    2012-01-01

    The potential for in situ biodegradation of tert-butyl alcohol (TBA) by creation of aerobic conditions in the subsurface with recirculating well pairs was investigated in two field studies conducted at Vandenberg Air Force Base (VAFB). In the first experiment, a single recirculating well pair with bromide tracer and oxygen amendment successfully delivered oxygen to the subsurface for 42 days. TBA concentrations were reduced from approximately 500 μg/L to below the detection limit within the treatment zone and the treated water was detected in a monitoring transect several meters downgradient. In the second experiment, a site-calibrated model was used to design a double recirculating well pair with oxygen amendment, which successfully delivered oxygen to the subsurface for 291 days and also decreased TBA concentrations to below the detection limit. Methylibium petroleiphilum strain PM1, a known TBA-degrading bacterium, was detectable at the study site but addition of oxygen had little impact on the already low baseline population densities, suggesting that there was not enough carbon within the groundwater plume to support significant new growth in the PM1 population. Given favorable hydrogeologic and geochemical conditions, the use of recirculating well pairs to introduce dissolved oxygen into the subsurface is a viable method to stimulate in situ biodegradation of TBA or other aerobically-degradable aquifer contaminants. PMID:23358537

  5. An Inexpensive Recirculating Aquaculture System with Multiple Use Capabilities.

    ERIC Educational Resources Information Center

    Scurlock, Gerald Don, Jr.; Cook, S. Bradford; Scurlock, Carrie Ann

    1999-01-01

    Describes the construction of an inexpensive recirculating aquaculture system that can hold up to 46 pounds of fish, invertebrates, and mussels for classroom use. The system is versatile, requires little maintenance, and can be used for both teaching and research purposes. (WRM)

  6. Use of low temperature blowers for recirculation of hot gases

    DOEpatents

    Maru, H.C.; Forooque, M.

    1982-08-19

    An apparatus is described for maintaining motors at low operating temperatures during recirculation of hot gases in fuel cell operations and chemical processes such as fluidized bed coal gasification. The apparatus includes a means for separating the hot process gas from the motor using a secondary lower temperature gas, thereby minimizing the temperature increase of the motor and associated accessories.

  7. Application of airlift technology in recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Marine hatcheries implementing recirculating aquaculture technology require pristine water quality and must be designed to provide a disease free environment as much as possible to limit disease transmission. Given the aggressive nature of a variety of marine pathogens, design considerations with re...

  8. Confined Turbulent Swirling Recirculating Flow Predictions. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Abujelala, M. T.

    1984-01-01

    Turbulent swirling flow, the STARPIC computer code, turbulence modeling of turbulent flows, the k-xi turbulence model and extensions, turbulence parameters deduction from swirling confined flow measurements, extension of the k-xi to confined swirling recirculating flows, and general predictions for confined turbulent swirling flow are discussed.

  9. Recirculating Beam Breakup Study for the 12 GeV Upgrade at Jefferson Lab

    SciTech Connect

    Ilkyoung Shin, Todd Satogata, Shahid Ahmed, Slawomir Bogacz, Mircea Stirbet, Haipeng Wang, Yan Wang, Byung Yunn, Ryan Bodenstein

    2012-07-01

    Two new high gradient C100 cryomodules with a total of 16 new cavities were installed at the end of the CEBAF south linac during the 2011 summer shutdown as part of the 12-GeV upgrade project at Jefferson Lab. We surveyed the higher order modes (HOMs) of these cavities in the Jefferson Lab cryomodule test facility and CEBAF tunnel. We then studied recirculating beam breakup (BBU) in November 2011 to evaluate CEBAF low energy performance, measure transport optics, and evaluate BBU thresholds due to these HOMs. This paper discusses the experiment setup, cavity measurements, machine setup, optics measurements, and lower bounds on BBU thresholds by new cryomodules.

  10. Screening and identification of SUMP-proteins in sub-acute treatment with diazinon

    PubMed Central

    Yazdian-Robati, Rezvan; Pourtaji, Atena; Rashedinia, Marzieh; Hosseinzadeh, Hossein; Ghorbani, Maryam; Razavi, BiBi Marjan; Ramezani, Mohammad; Abnous, Khalil

    2015-01-01

    Objective(s): Small ubiquitin-like modifiers (SUMOs) are a family of ubiquitin-related, proteins that are involved in a wide variety of signaling pathways. SUMOylation, as a vital post translational modification, regulate protein function in manycellular processes. Diazinon (DZN), an organophosphate insecticide, causses oxidative stress and subsequently programmed cell death in different tissues. The aim of this study was to evaluate the role and pattern of SUMO modificationas a defense mechanism against stress oxidative, in the heart tissuesof the DZN treated rats. Materials and Methods: Diazinon (15 mg/kg/day), corn oil (control) were administered via gavageto male Wistar rats for four weeks. SUMO1 antibody was covalently crosslinked to protein A/G agarose. heart tissue lysate were added to agarosebeads, After isolation of target proteins(SUMO1- protein)SDS-PAGE gel electrophoresis was performed. Protein bands were identified using MALDI-TOF/TOF and MASCOT). Fold change of (DZN/Ctrl) separated proteins was evaluated using UVband software (UVITEC, UK). Results: Our result showed that subacute exposure to DZN increased SUMOylationoffour key proteins involved in the metabolic process including; Acyl-CoA dehydrogenase, creatine kinase, glyceraldehyde-3-phosphate dehydrogenase and ATP synthase, in the heart tissue of animals. A probability value of less than 0.05 was considered significant (P<0.05). Conclusion: It seems that protein SUMOylation provides a safeguard mechanism against DZN Toxicity. PMID:26877855

  11. The potential use of constructed wetlands in a recirculating aquaculture system for shrimp culture.

    PubMed

    Lin, Ying-Feng; Jing, Shuh-Ren; Lee, Der-Yuan

    2003-01-01

    A pilot-scale constructed wetland unit, consisting of free water surface (FWS) and subsurface flow (SF) constructed wetlands arranged in series, was integrated into an outdoor recirculating aquaculture system (RAS) for culturing Pacific white shrimp (Litopenaeus vannamei). This study evaluated the performance of the wetland unit in treating the recirculating wastewater and examined the effect of improvement in water quality of the culture tank on the growth and survival of shrimp postlarvae. During an 80-day culture period, the wetland unit operated at a mean hydraulic loading rate of 0.3 m/day and effectively reduced the influent concentrations of 5-day biochemical oxygen demand (BOD5, 24%), suspended solids (SS, 71%), chlorophyll a (chl-a, 88%), total ammonium (TAN, 57%), nitrite nitrogen (NO2-N, 90%) and nitrate nitrogen (NO3-N, 68%). Phosphate (PO4-P) reduction was the least efficient (5.4%). The concentrations of SS, Chl-a, turbidity and NO3-N in the culture tank water in RAS were significantly (Precirculating system. PMID:12663210

  12. Effect of flue gas recirculation on heat transfer in a supercritical circulating fluidized bed combustor

    NASA Astrophysics Data System (ADS)

    Błaszczuk, Artur

    2015-09-01

    This paper focuses on assessment of the effect of flue gas recirculation (FGR) on heat transfer behavior in 1296t/h supercritical coal-fired circulating fluidized bed (CFB) combustor. The performance test in supercritical CFB combustor with capacity 966 MWth was performed with the low level of flue gas recirculation rate 6.9% into furnace chamber, for 80% unit load at the bed pressure of 7.7 kPa and the ratio of secondary air to the primary air SA/PA = 0.33. Heat transfer behavior in a supercritical CFB furnace between the active heat transfer surfaces (membrane wall and superheater) and bed material has been analyzed for Geldart B particle with Sauter mean diameters of 0.219 and 0.246 mm. Bed material used in the heat transfer experiments had particle density of 2700 kg/m3. A mechanistic heat transfer model based on cluster renewal approach was used in this work. A heat transfer analysis of CFB combustion system with detailed consideration of bed-to-wall heat transfer coefficient distributions along furnace height is investigated. Heat transfer data for FGR test were compared with the data obtained for representative conditions without recycled flue gases back to the furnace through star-up burners.

  13. Research on leachate recirculation from different types of landfills

    SciTech Connect

    Wang Qi . E-mail: wangqi@craes.org.cn; Matsufuji, Yasushi; Dong Lu; Huang Qifei; Hirano, Fumiaki; Tanaka, Ayako

    2006-07-01

    Landfills can produce a great amount of leachate containing highly concentrated organic matter. This is especially true for the initial leachate from landfilled municipal solid wastes (MSW) that generally has concentrations of COD{sub Cr} and BOD{sub 5} up to 80,000 and 50,000 mg/L, respectively. The leachate could be disposed by means of recirculating technique, which decomposes the organics through the action of proliferating microorganisms and thereby purifies the leachate, and simultaneously accelerates organic decomposition through water saturation control. Data from experimental results indicated that leachate recirculating could reduce the organic concentration considerably, with a maximum reduction rate of COD{sub Cr} over 95%; and, using a semi-aerobic process, NH{sub 3}-N concentration of treated leachate could be under 10 mg/L. In addition, the organic concentration in MSW decreased greatly.

  14. Digital feedwater and recirculation flow control for GPUN Oyster Creek

    SciTech Connect

    Burjorjee, D. ); Gan, B. )

    1992-01-01

    This paper describes the digital system for feedwater and recirculation control that GPU Nuclear will be installing at Oyster Creek during its next outage - expected circa December 1992. The replacement was motivated by considerations of reliability and obsolescence - the analog equipment was aging and reaching the end of its useful life. The new system uses Atomic Energy of Canada Ltd.'s software platform running on dual, redundant, industrial-grade 386 computers with opto-isolated field input/output (I/O) accessed through a parallel bus. The feedwater controller controls three main feed regulating valves, two low flow regulating valves, and two block valves. The recirculation controller drives the five scoop positioners of the hydraulic couplers. The system also drives contacts that lock up the actuators on detecting an open circuit in their current loops.

  15. Leachate pre-treatment strategies before recirculation in landfill bioreactors.

    PubMed

    Vigneron, V; Bouchez, T; Bureau, C; Mailly, N; Mazeas, L; Duquennoi, C; Audic, J M; Hébé, L; Bernet, N

    2005-01-01

    Nitrified leachate recirculation represents a promising strategy for a more sustainable landfill management. Our objective was to determine the reactions involved in nitrate reduction in municipal solid waste batch biodegradation tests. Anaerobic digestion of waste in the three control reactors showed a good reproducibility. In two test reactors, nitrate was added at various moments of the waste degradation process. We observed that: (1) H2S concentration controlled the nitrate reduction pathway: above a certain threshold of H2S, dissimilatory nitrate reduction to ammonium (DNRA) replaced denitrification. (2) N2O/N2 ratio varied with the organic carbon concentration: the lower the easily biodegradable carbon concentration, the higher the N2O/N2 ratio. (3) N2 was consumed after denitrification. The possibility of a nitrogen fixation reaction in the presence of NH4 is discussed. Nitrified leachate recirculation during acidogenesis should be avoided because of higher H2S production which could induce DNRA. PMID:16180441

  16. Recirculation of reverse osmosis concentrate in lab-scale anaerobic and aerobic landfill simulation reactors.

    PubMed

    Morello, Luca; Cossu, Raffaello; Raga, Roberto; Pivato, Alberto; Lavagnolo, Maria Cristina

    2016-10-01

    Leachate treatment is a major issue in the context of landfill management, particularly in view of the consistent changes manifested over time in the quality and quantity of leachate produced, linked to both waste and landfill characteristics, which renders the procedure technically difficult and expensive. Leachate recirculation may afford a series of potential advantages, including improvement of leachate quality, enhancement of gas production, acceleration of biochemical processes, control of moisture content, as well as nutrients and microbe migration within the landfill. Recirculation of the products of leachate treatment, such as reverse osmosis (RO) concentrate, is a less common practice, with widespread controversy relating to its suitability, potential impacts on landfill management and future gaseous and leachable emissions. Scientific literature provides the results of only a few full-scale applications of concentrate recirculation. In some cases, an increase of COD and ammonium nitrogen in leachate was observed, coupled with an increase of salinity; which, additionally, might negatively affect performance of the RO plant itself. In other cases, not only did leachate production not increase significantly but the characteristics of leachate extracted from the well closest to the re-injection point also remained unchanged. This paper presents the results of lab-scale tests conducted in landfill simulation reactors, in which the effects of injection of municipal solid waste (MSW) landfill leachate RO concentrate were evaluated. Six reactors were managed with different weekly concentrate inputs, under both anaerobic and aerobic conditions, with the aim of investigating the short and long-term effects of this practice on landfill emissions. Lab-scale tests resulted in a more reliable identification of compound accumulation and kinetic changes than full-scale applications, further enhancing the development of a mass balance in which gaseous emissions and waste

  17. Control of synchrotron radiation effects during recirculation with bunch compression

    SciTech Connect

    Douglas, David; Benson, Stephen; Li, Rui; Roblin, Yves; Tennant, Christopher; Krafft, Geoffrey; Terzic, Balsa; Tsai, Cheng

    2015-05-01

    Studies of beam quality during recirculation have been extended to an arc providing bunch compression with positive momentum compaction. It controls both incoherent and coherent synchrotron radiation (ISR and CSR) using methods including optics balance and generates little microbunching gain. We detail the dynamical basis for the design, discuss the design process, give an example, and provide simulations of ISR and CSR effects. Reference will be made to a complete analysis of microbunching effects.

  18. Tracking studies in eRHIC energy-recovery recirculator

    SciTech Connect

    Meot, F.; Brooks, S.; Ptitsyn, V.; Trbojevic, D.; Tsoupas, N.

    2015-07-13

    Beam and polarization tracking studies in eRHIC energy recovery electron recirculator are presented, based on a very preliminary design of the FFAG lattice. These simulations provide examples of some of the beam and spin optics aspects of the linear FFAG lattice concept and its application in eRHIC, they provide code benchmarking for synchrotron radiation and spin diffusion in addition, and pave the way towards end-to-end 6-D(phasespace)+3D(spin) tracking simulations.

  19. Cyclone reactor with internal separation and axial recirculation

    DOEpatents

    Becker, F.E.; Smolensky, L.A.

    1988-07-19

    A cyclone combustor apparatus contains a circular partition plate containing a central circular aperture is described. The partition plate divides the apparatus into a cylindrical precombustor chamber and a combustor chamber. A coal-water slurry is passed axially into the inlet end of the precombustor chamber, and primary air is passed tangentially into said chamber to establish a cyclonic air flow. Combustion products pass through the partition plate aperture and into the combustor chamber. Secondary air may also be passed tangentially into the combustor chamber adjacent the partition plate to maintain the cyclonic flow. Flue gas is passed axially out of the combustor chamber at the outlet end and ash is withdrawn tangentially from the combustor chamber at the outlet end. A first mixture of flue gas and ash may be tangentially withdrawn from the combustor chamber at the outlet end and recirculated to the axial inlet of the precombustor chamber with the coal-water slurry. A second mixture may be tangentially withdrawn from the outlet end and passed to a heat exchanger for cooling. Cooled second mixture is then recirculated to the axial inlet of the precombustor chamber. In another embodiment a single cyclone combustor chamber is provided with both the recirculation streams of the first mixture and the second mixture. 10 figs.

  20. Cyclone reactor with internal separation and axial recirculation

    DOEpatents

    Becker, Frederick E.; Smolensky, Leo A.

    1989-01-01

    A cyclone combustor apparatus contains a circular partition plate containing a central circular aperture. The partition plate divides the apparatus into a cylindrical precombustor chamber and a combustor chamber. A coal-water slurry is passed axially into the inlet end of the precombustor chamber, and primary air is passed tangentially into said chamber to establish a cyclonic air flow. Combustion products pass through the partition plate aperture and into the combustor chamber. Secondary air may also be passed tangentially into the combustor chamber adjacent the partition plate to maintain the cyclonic flow. Flue gas is passed axially out of the combustor chamber at the outlet end and ash is withdrawn tangentially from the combuston chamber at the outlet end. A first mixture of flue gas and ash may be tangentially withdrawn from the combustor chamber at the outlet end and recirculated to the axial inlet of the precombustor chamber with the coal-water slurry. A second mixture of flue gas and ash may be tangentially withdrawn from the outlet end of the combustor chamber and passed to a heat exchanger for cooling. Cooled second mixture is then recirculated to the axial inlet of the precombustor chamber. In another embodiment a single cyclone combustor chamber is provided with both the recirculation streams of the first mixture and the second mixture.

  1. Hydroxyl time series and recirculation in turbulent nonpremixed swirling flames

    SciTech Connect

    Guttenfelder, Walter A.; Laurendeau, Normand M.; Ji, Jun; King, Galen B.; Gore, Jay P.; Renfro, Michael W.

    2006-10-15

    Time-series measurements of OH, as related to accompanying flow structures, are reported using picosecond time-resolved laser-induced fluorescence (PITLIF) and particle-imaging velocimetry (PIV) for turbulent, swirling, nonpremixed methane-air flames. The [OH] data portray a primary reaction zone surrounding the internal recirculation zone, with residual OH in the recirculation zone approaching chemical equilibrium. Modeling of the OH electronic quenching environment, when compared to fluorescence lifetime measurements, offers additional evidence that the reaction zone burns as a partially premixed flame. A time-series analysis affirms the presence of thin flamelet-like regions based on the relation between swirl-induced turbulence and fluctuations of [OH] in the reaction and recirculation zones. The OH integral time-scales are found to correspond qualitatively to local mean velocities. Furthermore, quantitative dependencies can be established with respect to axial position, Reynolds number, and global equivalence ratio. Given these relationships, the OH time-scales, and thus the primary reaction zone, appear to be dominated by convection-driven fluctuations. Surprisingly, the OH time-scales for these nominally swirling flames demonstrate significant similarities to previous PITLIF results in nonpremixed jet flames. (author)

  2. Recirculating, passive micromixer with a novel sawtooth structure.

    PubMed

    Nichols, Kevin P; Ferullo, Julia R; Baeumner, Antje J

    2006-02-01

    A microfluidic device capable of recirculating nano to microlitre volumes in order to efficiently mix solutions is described. The device consists of molded polydimethyl siloxane (PDMS) channels with pressure inlet and outlet holes sealed by a glass lid. Recirculation is accomplished by a repeatedly reciprocated flow over an iterated sawtooth structure. The sawtooth structure serves to change the fluid velocity of individual streamlines differently depending on whether the fluid is flowing backwards or forward over the structure. Thus, individual streamlines can be accelerated or decelerated relative to the other streamlines to allow sections of the fluid to interact that would normally be linearly separated. Low Reynolds numbers imply that the process is reversible, neglecting diffusion. Computer simulations were carried out using FLUENT. Subsequently, fluorescent indicators were employed to experimentally verify these numerical simulations of the recirculation principal. Finally, mixing of a carboxyfluorescein labeled DMSO plug with an unlabeled DMSO plug across an immiscible hydrocarbon plug was investigated. At cycling rates of 1 Hz across five sawtooth units, the time was recorded to reach steady state in the channels, i.e. until both DMSO plugs had the same fluorescence intensity. In the case of the sawtooth structures, steady state was reached five times faster than in channels without sawtooth structures, which verified what would be expected based on numerical simulations. The microfluidic mixer is unique due to its versatility with respect to scaling, its potential to also mix solutions containing small particles such as beads and cells, and its ease of fabrication and use. PMID:16450034

  3. Modeling of leachate recirculation using vertical wells in bioreactor landfills.

    PubMed

    Feng, Shi-Jin; Cao, Ben-Yi; Zhang, Xu; Xie, Hai-Jian

    2015-06-01

    Leachate recirculation (LR) in municipal solid waste (MSW) landfills operated as bioreactors offers significant economic and environmental benefits. The subsurface application method of vertical wells is one of the most common LR techniques. The objective of this study was to develop a novel two-dimensional model of leachate recirculation using vertical wells. This novel method can describe leachate flow considering the effects of MSW settlement while also accounting separately for leachate flow in saturated and unsaturated zones. In this paper, a settlement model for MSW when considering the effects of compression and biodegradation on the MSW porosity was adopted. A numerical model was proposed using new governing equations for the saturated and unsaturated zones of a landfill. The following design parameters were evaluated by simulating the recirculated leachate volume and the influence zones of waste under steady-state flow conditions: (1) the effect of MSW settlement, (2) the effect of the initial void ratio, (3) the effect of the injected head, (4) the effect of the unit weight, (5) the effect of the biodegradation rate, and (6) the effect of the compression coefficient. The influence zones of LR when considering the effect of MSW settlement are smaller than those when neglecting the effect. The influence zones and LR volume increased with an increase in the injection pressure head and initial void ratio of MSW. The proposed method and the calculation results can provide important insight into the hydrological behavior of bioreactor landfills. PMID:25874416

  4. Noscapine recirculates enterohepatically and induces self-clearance.

    PubMed

    Mukkavilli, Rao; Gundala, Sushma R; Yang, Chunhua; Jadhav, Gajanan R; Vangala, Subrahmanyam; Reid, Michelle D; Aneja, Ritu

    2015-09-18

    Noscapine (Nos), an antitussive benzylisoquinoline opium alkaloid, is a non-toxic tubulin-binding agent currently in Phase II clinical trials for cancer chemotherapy. While preclinical studies have established its tumor-inhibitory properties in various cancers, poor absorptivity and rapid first-pass metabolism producing several uncharacterized metabolites for efficacy, present an impediment in translating its efficacy in humans. Here we report novel formulations of Nos in combination with dietary agents like capsaicin (Cap), piperine (Pip), eugenol (Eu) and curcumin (Cur) known for modulating Phase I and II drug metabolizing enzymes. In vivo pharmacokinetic (PK), organ toxicity evaluation of combinations, microsomal stability and in vitro cytochrome P450 (CYP) inhibition effects of Nos, Cap and Pip using human liver microsomes were performed. Single-dose PK screening of combinations revealed that the relative exposure of Nos (2 μg h/mL) was enhanced by 2-fold (4 μg h/mL) by Cap and Pip and their plasma concentration-time profiles showed multiple peaking phenomena for Nos indicating enterohepatic recirculation or differential absorption from intestine. CYP inhibition studies confirmed that Nos, Cap and Pip are not potent CYP inhibitors (IC50>1 μM). Repeated oral dosing of Nos, Nos+Cap and Nos+Pip showed lower exposure (Cmax and AUClast) of Nos on day 7 compared to day 1. Nos Cmax decreased from 3087 ng/mL to 684 ng/mL and AUClast from 1024 ng h/mL to 508 ng h/mL. In presence of Cap and Pip, the decrease in Cmax and AUClast of Nos was similar. This may be due to potential enzyme induction leading to rapid clearance of Nos as the trend was observed in Nos alone group also. The lack of effect on intrinsic clearance of Nos suggests that the potential drug biotransformation modulators employed in this study did not contribute toward increased exposure of Nos on repeated dosing. We envision that Nos-induced enzyme induction could alter the therapeutic efficacy of co

  5. Investigation on inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet

    NASA Astrophysics Data System (ADS)

    Yang, Ce; Wang, Yingjun; Lao, Dazhong; Tong, Ding; Wei, Longyu; Liu, Yixiong

    2016-08-01

    The inlet recirculation characteristics of double suction centrifugal compressor with unsymmetrical inlet structures were studied in numerical method, mainly focused on three issues including the amounts and differences of the inlet recirculation in different working conditions, the circumferential non-uniform distributions of the inlet recirculation, the recirculation velocity distributions of the upstream slot of the rear impeller. The results show that there are some differences between the recirculation of the front impeller and that of the rear impeller in whole working conditions. In design speed, the recirculation flow rate of the rear impeller is larger than that of the front impeller in the large flow range, but in the small flow range, the recirculation flow rate of the rear impeller is smaller than that of the front impeller. In different working conditions, the recirculation velocity distributions of the front and rear impeller are non-uniform along the circumferential direction and their non-uniform extents are quite different. The circumferential non-uniform extent of the recirculation velocity varies with the working conditions change. The circumferential non-uniform extent of the recirculation velocity of front impeller and its distribution are determined by the static pressure distribution of the front impeller, but that of the rear impeller is decided by the coupling effects of the inlet flow distortion of the rear impeller, the circumferential unsymmetrical distribution of the upstream slot and the asymmetric structure of the volute. In the design flow and small flow conditions, the recirculation velocities at different circumferential positions of the mean line of the upstream slot cross-section of the rear impeller are quite different, and the recirculation velocities distribution forms at both sides of the mean line are different. The recirculation velocity distributions in the cross-section of the upstream slot depend on the static pressure

  6. Recirculation of Laser Power in an Atomic Fountain

    NASA Technical Reports Server (NTRS)

    Enzer, Daphna G.; Klipstein, WIlliam M.; Moore, James D.

    2007-01-01

    A new technique for laser-cooling atoms in a cesium atomic fountain frequency standard relies on recirculation of laser light through the atom-collection region of the fountain. The recirculation, accomplished by means of reflections from multiple fixed beam-splitter cubes, is such that each of two laser beams makes three passes. As described below, this recirculation scheme offers several advantages over prior designs, including simplification of the laser system, greater optical power throughput, fewer optical and electrical connections, and simplification of beam power balancing. A typical laser-cooled cesium fountain requires the use of six laser beams arranged as three orthogonal pairs of counter-propagating beams to decelerate the atoms and hold them in a three-dimensional optical trap in vacuum. Typically, these trapping/cooling beams are linearly polarized and are positioned and oriented so that (1) counter-propagating beams in each pair have opposite linear polarizations and (2) three of the six orthogonal beams have the sum of their propagation directions pointing up, while the other three have the sum of their propagation directions pointing down. In a typical prior design, two lasers are used - one to generate the three "up" beams, the other to generate the three "down" beams. For this purpose, the output of each laser is split three ways, then the resulting six beams are delivered to the vacuum system, independently of each other, via optical fibers. The present recirculating design also requires two lasers, but the beams are not split before delivery. Instead, only one "up" beam and one oppositely polarized "down" beam are delivered to the vacuum system, and each of these beams is sent through the collection region three times. The polarization of each beam on each pass through the collection region is set up to yield the same combination of polarization and propagation directions as described above. In comparison with the prior design, the present

  7. Investigating the influence of nitrate nitrogen on post-smolt Atlantic salmon Salmo salar reproductive physiology in water recirculation aquaculture systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An 8-month trial was carried out to assess the effects of NO3-N on a variety of performance and physiological outcomes in post-smolt Atlantic salmon Salmo salar (initial weight 102 plus or minus 1 g) reared in six replicated laboratory-scale water recirculation aquaculture systems (RAS). Three RAS r...

  8. The impact of water exchange rate and treatment processes on water-borne hormones in recirculation aquaculture systems containing sexually maturing Atlantic salmon Salmo salar

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A controlled seven-month study was conducted in six replicated water recirculation aquaculture systems (WRAS) to assess post-smolt Atlantic salmon (Salmo salar) performance in relation to WRAS water exchange rate. Unexpectedly high numbers of precocious sexually mature fish were observed in all WRAS...

  9. Novel concept development of an internal recirculation catalyst for mild gasification

    SciTech Connect

    Knight, R.A.; Babu, S.P.; Martin, K.A.; Chao, S.C.

    1988-10-01

    The objective of this program is to provide an overall evaluation of a novel process concept for mild gasification by completing work in three major tasks: (1) Laboratory-Scale Experiments, (2) Bench-Scale Tests, and (3) Proof-of-Concept Tests and Evaluation (optional). During this quarter, experimental work involving potential recirculating catalysts for coal, initiated in the previous quarter, was continued. The construction and shakedown of an all quartz laboratory-scale isothermal free-fall reactor was completed. Three free-fall experiments were performed in an existing stainless-steel free-fall reactor with untreated and ammonia treated Illinois No. 6 high-voltatile bituminous coal, and the analyzed data are presented herein. A survey of available literature on catalyzed devolatilization of coal, coal pretreatment methods, and related topics was made. Based on the results of this survey, two potential recirculating catalysts, in addition to the already selected zinc chloride, were selected for study: ferrous chloride (FeCl{sub 2}) and ferric chloride (FeCl{sub 3}). Also, based on the survey, two coal pretreatment/chemical comminution methods were selected for study, in addition to methanol treatment: ammonia and n-butylamine pretreatment. A matrix of experiments was formulated to study the three catalysts and three pretreatment methods selected. 2 refs., 2 tabs.

  10. Nitrification in brackish water recirculating aquaculture system integrated with activated packed bed bioreactor.

    PubMed

    Rejish Kumar, V J; Joseph, Valsamma; Philip, Rosamma; Bright Singh, I S

    2010-01-01

    Recirculation aquaculture systems (RAS) depend on nitrifying biofilters for the maintenance of water quality, increased biosecurity and environmental sustainability. To satisfy these requirements a packed bed bioreactor (PBBR) activated with indigenous nitrifying bacterial consortia has been developed and commercialized for operation under different salinities for instant nitrification in shrimp and prawn hatchery systems. In the present study the nitrification efficiency of the bioreactor was tested in a laboratory level recirculating aquaculture system for the rearing of Penaeus monodon for a period of two months under higher feeding rates and no water exchange. Rapid setting up of nitrification was observed during the operation, as the volumetric total ammonia nitrogen removal rates (VTR) increased with total ammonia nitrogen (TAN) production in the system. The average Volumetric TAN Removal Rates (VTR) at the feeding rate of 160 g/day from 54-60th days of culture was 0.1533+/-0.0045 kg TAN/m(3)/day. The regression between VTR and TAN explained 86% variability in VTR (P<0.001). The laboratory level RAS demonstrated here showed high performance both in terms of shrimp biomass yield and nitrification and environmental quality maintenance. Fluorescent in-situ Hybridization analysis of the reactor biofilm ensured the presence of autotrophic nitrifier groups such as Nitrosococcus mobilis lineage, Nitrobacter spp and phylum Nitrospira, the constituent members present in the original consortia used for activating the reactors. This showed the stability of the consortia on long term operation. PMID:20150717

  11. Investigation of sludge re-circulating clarifiers design and optimization through numerical simulation.

    PubMed

    Davari, S; Lichayee, M J

    2003-01-01

    In steam thermal power plants (TPP) with open re-circulating wet cooling towers, elimination of water hardness and suspended solids (SS) is performed in clarifiers. Most of these clarifiers are of high efficiency sludge re-circulating type (SRC) with capacity between 500-1,500 m3/hr. Improper design and/or mal-operation of clarifiers in TPPs results in working conditions below design capacity or production of soft water with improper quality (hardness and S.S.). This causes accumulation of deposits in heat exchangers, condenser tubes, cooling and service water pipes and boiler tubes as well as increasing the ionic load of water at the demineralizing system inlet. It also increases the amount of chemical consumptions and produces more liquid and solid waste. In this regard, a software program for optimal design and simulation of SRCs has been developed. Then design parameters of existing SRCs in four TPPs in Iran were used as inputs to developed software program and resulting technical specifications were compared with existing ones. In some cases improper design was the main cause of poor outlet water quality. In order to achieve proper efficiency, further investigations were made to obtain control parameters as well as design parameters for both mal-designed and/or mal-operated SRCs. PMID:14753549

  12. Small scale recirculating vertical flow constructed wetland (RVFCW) for the treatment and reuse of wastewater.

    PubMed

    Gross, A; Sklarz, M Y; Yakirevich, A; Soares, M I M

    2008-01-01

    The quantity of freshwater available worldwide is declining, revealing a pressing need for its more efficient use. Moreover, in many developing countries and lightly populated areas, raw wastewater is discarded into the environment posing serious ecological and health problems. Unfortunately, this situation will persist unless low-cost, effective and simple technologies are brought in. The aim of this study is to present such a treatment method, a novel setup which is termed recirculating vertical flow constructed wetland (RVFCW). The RVFCW is composed of two components: (i) a three-layer bed consisting of planted organic soil over an upper layer of filtering media (i.e. tuff or beads) and a lower layer of limestone pebbles, and (ii) a reservoir located beneath the bed. Wastewater flows directly into the plant root zone and trickles down through the three-layer bed into the reservoir, allowing passive aeration. From the reservoir the water is recirculated back to the bed, several times, until the desired purification is achieved. The results obtained show that the RVFCW is an effective and convenient strategy to treat (domestic, grey and agro) wastewater for re-use in irrigation. The system performance is expected to be further improved once current optimization experiments and mathematical modeling studies are concluded. PMID:18701805

  13. Energy balance affected by electrolyte recirculation and operating modes in microbial fuel cells.

    PubMed

    Jacobson, Kyle S; Kelly, Patrick T; He, Zhen

    2015-03-01

    Energy recovery and consumption in a microbial fuel cell (MFC) can be significantly affected by the operating conditions. This study investigated the effects of electrolyte recirculation and operation mode (continuous vs sequence batch reactor) on the energy balance in a tubular MFC. It was found that decreasing the anolyte recirculation also decreased the energy recovery. Because of the open environment of the cathode electrode, the catholyte recirculation consumed 10 to 50 times more energy than the anolyte recirculation, and resulted in negative energy balances despite the reduction of the anolyte recirculation. Reducing the catholyte recirculation to 20% led to a positive energy balance of 0.0288 kWh m(-3). The MFC operated as a sequence batch reactor generated less energy and had a lower energy balance than the one with continuous operation. Those results encourage the further development of MFC technology to achieve neutral or even positive energy output. PMID:25842536

  14. Recirculation-aeration: Bibliography for aquaculture. Bibliographies and literature of agriculture (Final)

    SciTech Connect

    Perschbacher, P.W.; Powell, R.V.; Freeman, D.W.; Lorio, W.J.; Hanfman, D.T.

    1993-08-01

    The bibliography includes literature citations through 1992 related to water recirculation and aeration in aquaculture. The focus is on filtration, aeration, and circulation techniques in various aquaculture situations.

  15. The STREON Recirculation Chamber: An Advanced Tool to Quantify Stream Ecosystem Metabolism in the Benthic Zone

    NASA Astrophysics Data System (ADS)

    Brock, J. T.; Utz, R.; McLaughlin, B.

    2013-12-01

    ) under various velocity settings. The extent of exchange with the sediment was assessed by means of a saline tracer injection and adjustment using flow-regulating components was explored. Performance under a broad range of temperatures (1 to 30 °C) was assessed. Finally, a novel heat-exchange mechanism meant to minimize warming during operations was evaluated. All prototype assessments demonstrate the applicability of the STREON chamber under a broad range of conditions. Though the STREON recirculation chamber has been designed to satisfy the specific needs of the STREON program, the open-access nature of the NEON network should facilitate scope expansion in the coming decades. The STREON recirculation chamber design and all prototype testing data will be accessible to facilitate chamber use elsewhere. The large number of chamber assemblies required for STREON operations should facilitate the acquisition of units by researchers working outside of the NEON network. Furthermore, the current scope of STREON includes the use of the chambers only once annually, thus a valuable tool for stream ecosystem measurements will be readily available at STREON sites for potential use by researchers interested in such measurements.

  16. A recirculating hydroponic system for studying peanut (Arachis hypogaea L.)

    NASA Technical Reports Server (NTRS)

    Mackowiak, C. L.; Wheeler, R. M.; Stutte, G. W.; Yorio, N. C.; Ruffe, L. M.; Sager, J. C. (Principal Investigator)

    1998-01-01

    Peanut (Arachis hypogaea L.) plants were grown hydroponically, using continuously recirculating nutrient solution. Two culture tray designs were tested; one tray design used only nutrient solution, while the other used a sphagnum-filled pod development compartment just beneath the cover and above the nutrient solution. Both trays were fitted with slotted covers to allow developing gynophores to reach the root zone. Peanut seed yields averaged 350 gm-2 dry mass, regardless of tray design, suggesting that substrate is not required for hydroponic peanut production.

  17. Gun and optics calculations for the Fermilab recirculation experiment

    SciTech Connect

    Kroc, T.

    1997-10-01

    Fermilab is investigating electron cooling to recycle 8 Gev antiprotons recovered from the Tevatron. To do so, it is developing an experiment to recirculate 2 Mev electrons generated by a Pelletron at National Electrostatics Corporation. This paper reports on the optics calculations done in support of that work. We have used the computer codes EGN2 and MacTrace to represent the gun area and acceleration columns respectively. In addition to the results of our simulations, we discuss some of the problems encountered in interfacing the two codes.

  18. Tools to Predict Beam Breakup in Recirculating Linacs

    SciTech Connect

    Kevin Beard; Nikolitsa Merminga; Byung Yunn

    2003-05-01

    An important limitation on the maximum beam current in a recirculating linac is due to beam breakup caused by higher order modes (HOM) excited in the RF cavities. A HOM delivers a transverse kick to a beam bunch, the bunch on the next pass can then drive the HOM and cause it to grow until the beam is lost. Two codes, MATBBU1 and TDBBU2, have been written to estimate the threshold current for a set of HOMs and accelerator optics. The relative merits and limitations of each is discussed in detail.

  19. Bio-inspired robotic legs drive viscous recirculating flows

    NASA Astrophysics Data System (ADS)

    Takagi, Daisuke; Hayashi, Rintaro

    2015-11-01

    Crustaceans actuate multiple legs in a well-coordinated sequence to generate suitable flow for feeding and swimming. Inspired by tiny crustacean larvae operating at low Reynolds number, we study a scaled-up model in which slender rods oscillate independently in a bath of glycerol. Experiments reveal qualitatively different flow patterns depending on the phase and orientation of actuated rods. The observations are analyzed in the framework of slender-body theory for Stokes flow. This study shows that simple oscillatory motion of multiple legs can produce complex recirculating flows, with potential applications for mixing and pumping.

  20. Power plant including an exhaust gas recirculation system for injecting recirculated exhaust gases in the fuel and compressed air of a gas turbine engine

    DOEpatents

    Anand, Ashok Kumar; Nagarjuna Reddy, Thirumala Reddy; Shaffer, Jason Brian; York, William David

    2014-05-13

    A power plant is provided and includes a gas turbine engine having a combustor in which compressed gas and fuel are mixed and combusted, first and second supply lines respectively coupled to the combustor and respectively configured to supply the compressed gas and the fuel to the combustor and an exhaust gas recirculation (EGR) system to re-circulate exhaust gas produced by the gas turbine engine toward the combustor. The EGR system is coupled to the first and second supply lines and configured to combine first and second portions of the re-circulated exhaust gas with the compressed gas and the fuel at the first and second supply lines, respectively.

  1. GIT (Glucose Infusion Test): polycentric evaluation of a new test for vascular access recirculation.

    PubMed

    Alloatti, S; Magnasco, A; Bonfant, G; Bonello, F; Ciciani, A M; Fidelio, T; Filiberti, O; Forneris, G; Martina, G; Robaudo, C; Romano, U; Schelotto, C

    2000-01-01

    Introduction. Vascular access recirculation (AR), which is often unacknowledged, remains an important cause of inadequate dialytic dose. The glucose infusion test (GIT) is a new method for detecting and quantifying AR. This paper reports on a polycentric evaluation of the new test and a comparison with the classical Urea-test (UT). Methods. GIT protocol comprises withdrawal from the arterial port (sample A), injection into the venous drip chamber of 1 g glucose in 4 seconds, withdrawal from the arterial port (sample B) continuously from 13 to 17 seconds. Glucose is determined on A and B by a reflectance photometer. If B = A then there is no recirculation. If B exceeds A by at least 20 mg/dl there is recirculation. AR quantification: AR% = (B-A) / 20. GIT was performed on 623 patients from eleven dialysis centers to screen the patients for AR. Subsequently, GIT and Urea-test (UT) were compared in 189 paired tests. The reproducibility of GIT and UT was studied in 28 paired tests performed in sequence. Results. The screening test by GIT was positive in 68 cases (11 %). The majority of positivities was found in central venous catheters (CVC, 27/50 cases, 54 %), whereas only 7 % of artero-venous fistulas (AVF) were positive. In the CVC group, Tesio catheters were more frequently positive compared to Dual Lumen Catheters (64 % vs. 29 %). The comparison GIT - UT showed that results matched in 162 tests (79 negative and 83 positive both by GIT and UT), showing that on the grounds of UT, GIT has high sensitivity and specificity. In 27 tests GIT was positive, but UT negative. This disagreement is due to the different minimal limit of detection, 1 % for GIT and 5% for UT. The reproducibility was greater with GIT than with UT with a lower D% (respectively -0.6 +/- 2.5 and -0.4 +/- 6.1 %, p<0.001) and a lower coefficient of variation (17 vs 33 %). Conclusions. The screening of 623 patients by GIT confirmed that AR in AVF is normally absent, whereas an un-expectedly high

  2. Evaluation of a Shaker Dust Collector for Use in a Recirculating Ventilation System.

    PubMed

    Peters, Thomas M; Sawvel, Russell A; Park, Jae Hong; Anthony, T Renée

    2015-01-01

    General ventilation with recirculated air may be cost-effective to control the concentration of low-toxicity, contaminants in workplaces with diffuse, dusty operations, such as in agriculture. Such systems are, however, rarely adopted with little evidence showing improved air quality and ability to operate under harsh conditions. The goal of this work was to examine the initial and long-term performance of a fabric-filter shaker dust collector (SDC) in laboratory tests and as deployed within a recirculating ventilation system in an agricultural building. In laboratory tests, collection efficiency and pressure drop were tracked over several filter loading cycles, and the recovery of filter capacity (pressure drop) from filter shaking was examined. Collection efficiencies of particles larger than 5 μm was high (>95%) even when the filter was pristine, showing effective collection of large particles that dominate inhalable concentrations typical of agricultural dusts. For respirable-sized particles, collection efficiencies were low when the filter was pristine (e.g., 27% for 1 μm) but much higher when a dust cake developed on the filter (>99% for all size particles), even after shaking (e.g., 90% for 1 μm). The first shake of a filter was observed to recovery a substantial fraction of filter capacity, with subsequent shakes providing little benefit. In field tests, the SDC performed effectively over a period of three months in winter when incorporated in a recirculating ventilation system of a swine farrowing room. Trends in collection efficiency and pressure drop with loading were similar to those observed in the laboratory with overall collection efficiencies high (>80%) when pressure drop exceeded 230 Pa, or 23% of the maximum loading recommended by the manufacturer. This work shows that the SDC can function effectively over the harsh winter in swine rearing operations. Together with findings of improved air quality in the farrowing room reported in a

  3. Evaluation of a Shaker Dust Collector for Use in a Recirculating Ventilation System

    PubMed Central

    Sawvel, Russell A.; Park, Jae Hong; Anthony, T. Renée

    2016-01-01

    General ventilation with recirculated air may be cost-effective to control the concentration of low-toxicity, contaminants in workplaces with diffuse, dusty operations, such as in agriculture. Such systems are, however, rarely adopted with little evidence showing improved air quality and ability to operate under harsh conditions. The goal of this work was to examine the initial and long-term performance of a fabric-filter shaker dust collector (SDC) in laboratory tests and as deployed within a recirculating ventilation system in an agricultural building. In laboratory tests, collection efficiency and pressure drop were tracked over several filter loading cycles, and the recovery of filter capacity (pressure drop) from filter shaking was examined. Collection efficiencies of particles larger than 5 μm was high (>95%) even when the filter was pristine, showing effective collection of large particles that dominate inhalable concentrations typical of agricultural dusts. For respirable-sized particles, collection efficiencies were low when the filter was pristine (e.g., 27% for 1 μm) but much higher when a dust cake developed on the filter (>99% for all size particles), even after shaking (e.g., 90% for 1 μm). The first shake of a filter was observed to recovery a substantial fraction of filter capacity, with subsequent shakes providing little benefit. In field tests, the SDC performed effectively over a period of three months in winter when incorporated in a recirculating ventilation system of a swine farrowing room. Trends in collection efficiency and pressure drop with loading were similar to those observed in the laboratory with overall collection efficiencies high (>80%) when pressure drop exceeded 230 Pa, or 23% of the maximum loading recommended by the manufacturer. This work shows that the SDC can function effectively over the harsh winter in swine rearing operations. Together with findings of improved air quality in the farrowing room reported in a companion

  4. Passive mode control in the recirculating planar magnetron

    SciTech Connect

    Franzi, Matthew; Gilgenbach, Ronald; Lau, Y. Y.; Greening, Geoff; Zhang, Peng; Hoff, Brad

    2013-03-15

    Preliminary experiments of the recirculating planar magnetron microwave source have demonstrated that the device oscillates but is susceptible to intense mode competition due, in part, to poor coupling of RF fields between the two planar oscillators. A novel method of improving the cross-oscillator coupling has been simulated in the periodically slotted mode control cathode (MCC). The MCC, as opposed to a solid conductor, is designed to electromagnetically couple both planar oscillators by allowing for the propagation of RF fields and electrons through resonantly tuned gaps in the cathode. Using the MCC, a 12-cavity anode block with a simulated 1 GHz and 0.26 c phase velocity (where c is the speed of light) was able to achieve in-phase oscillations between the two sides of the device in as little as 30 ns. An analytic study of the modified resonant structure predicts the MCC's ability to direct the RF fields to provide tunable mode separation in the recirculating planar magnetron. The self-consistent solution is presented for both the degenerate even (in phase) and odd (180 Degree-Sign out of phase) modes that exist due to the twofold symmetry of the planar magnetrons.

  5. Passive mode control in the recirculating planar magnetron

    NASA Astrophysics Data System (ADS)

    Franzi, Matthew; Gilgenbach, Ronald; Lau, Y. Y.; Hoff, Brad; Greening, Geoff; Zhang, Peng

    2013-03-01

    Preliminary experiments of the recirculating planar magnetron microwave source have demonstrated that the device oscillates but is susceptible to intense mode competition due, in part, to poor coupling of RF fields between the two planar oscillators. A novel method of improving the cross-oscillator coupling has been simulated in the periodically slotted mode control cathode (MCC). The MCC, as opposed to a solid conductor, is designed to electromagnetically couple both planar oscillators by allowing for the propagation of RF fields and electrons through resonantly tuned gaps in the cathode. Using the MCC, a 12-cavity anode block with a simulated 1 GHz and 0.26 c phase velocity (where c is the speed of light) was able to achieve in-phase oscillations between the two sides of the device in as little as 30 ns. An analytic study of the modified resonant structure predicts the MCC's ability to direct the RF fields to provide tunable mode separation in the recirculating planar magnetron. The self-consistent solution is presented for both the degenerate even (in phase) and odd (180° out of phase) modes that exist due to the twofold symmetry of the planar magnetrons.

  6. High-energy Picosecond Laser Pulse Recirculation for Compton Scattering

    SciTech Connect

    Jovanovic, I; Anderson, S G; Betts, S M; Brown, C; Gibson, D J; Hartemann, F V; Hernandez, J E; Johnson, M; McNabb, D P; Messerly, M; Pruet, J; Shverdin, M Y; Siders, C W; Tremaine, A M; Barty, C J

    2007-06-12

    Frequency upconversion of laser-generated photons by inverse Compton scattering for applications such as nuclear spectroscopy and gamma-gamma collider concepts on the future ILC would benefit from an increase of average source brightness. The primary obstacle to higher average brightness is the relatively small Thomson scattering cross section. It has been proposed that this limitation can be partially overcome by use of laser pulse recirculation. The traditional approach to laser recirculation entails resonant coupling of low-energy pulse train to a cavity through a partially reflective mirror. Here we present an alternative, passive approach that is akin to 'burst-mode' operation and does not require interferometric alignment accuracy. Injection of a short and energetic laser pulse is achieved by placing a thin frequency converter, such as a nonlinear optical crystal, into the cavity in the path of the incident laser pulse. This method leads to the increase of x-ray/gamma-ray energy proportional to the increase in photon energy in frequency conversion. Furthermore, frequency tunability can be achieved by utilizing parametric amplifier in place of the frequency converter.

  7. Continuous hydroponic wheat production using a recirculating system

    NASA Technical Reports Server (NTRS)

    Mackowiak, C. L.; Owens, L. P.; Hinkle, C. R.; Prince, R. P.

    1989-01-01

    Continuous crop production, where plants of various ages are growing simultaneously in a single recirculating nutrient solution, is a possible alternative to batch production in a Controlled Ecological Life Support System. A study was conducted at John F. Kennedy Space Center where 8 trays (0.24 sq m per tray) of Triticum aestivum L. Yecora Rojo were grown simultaneously in a growth chamber at 23 C, 65 percent relative humidity, 1000 ppm CO2, continuous light, with a continuous flow, thin film nutrient delivery system. The same modified Hoagland nutrient solution was recirculated through the plant trays from an 80 L reservoir throughout the study. It was maintained by periodic addition of water and nutrients based on chemical analyses of the solution. The study was conducted for 216 days, during which 24 trays of wheat were consecutively planted (one every 9 days), 16 of which were grown to maturity and harvested. The remaining 8 trays were harvested on day 216. Grain yields averaged 520 g m(exp -2), and had an average edible biomass of 32 percent. Consecutive yields were unaffected by nutrient solution age. It was concluded that continual wheat production will work in this system over an extended period of time. Certain micronutrient deficiencies and toxicities posed problems and must be addressed in future continuous production systems.

  8. Designing and Testing of Self-Cleaning Recirculating Zebrafish Tanks.

    PubMed

    Nema, Shubham; Bhargava, Yogesh

    2016-08-01

    Maintenance of large number of zebrafish in captive conditions is a daunting task. This can be eased by the use of recirculating racks with self-cleaning zebrafish tanks. Commercially available systems are costly, and compatibility of intercompany products has never been investigated. Although various cost-effective designs and methods of construction of custom-made recirculating zebrafish racks are available in literature, the design of self-cleaning zebrafish tanks is still not available. In this study, we report the design and method of construction of the self-cleaning unit, which can be fitted in any zebrafish tank. We validated the design by investigating sediment cleaning process in rectangular and cylindrical tank geometries using time lapse imaging. Our results suggest that for both tank geometries, the tanks fitted with self-cleaning unit provided superior sediment cleaning than the tanks fitted with overflow-drain unit. Although the self-cleaning unit could clean the sediment completely from both geometries over prolonged period, the cleaning of sediments was faster in the cylindrical tank than the rectangular tank. In conclusion, cost and efforts of zebrafish maintenance could be significantly reduced through the installation of our self-cleaning unit in any custom-made zebrafish tank. PMID:27096937

  9. Suppression of Multipass, Multibunch Beam Breakup in Two Pass Recirculating Accelerators

    SciTech Connect

    Christopher Tennant; David Douglas; Kevin Jordan; Nikolitsa Merminga; Edvard Pozdeyev; Todd Smith

    2004-08-01

    Beam Breakup (BBU) occurs in all accelerators at sufficiently high currents. In recirculating accelerators, such as the energy recovery linacs used for high power FELs, the maximum current has historically been limited by multipass, multibunch BBU, a form that occurs when the electron beam interacts with the higher-order modes (HOMs) of an accelerating cavity on one pass and then again on the second pass. This effect is of particular concern in the designs of modern high average current energy recovery accelerators utilizing superconducting technology. In such two pass machines rotation of the betatron planes by 90a, first proposed by Smith and Rand in 1980 [1], should significantly increase the threshold current of the multibunch BBU. Using a newly developed two-dimensional tracking code, we study the effect of optical suppression techniques on the threshold current of the JLAB FEL Upgrade. We examine several optical rotator schemes and evaluate their performance in terms of the instability threshold current increase.

  10. Closed water recirculating system for fish rearing equipped with bioreactor capable of simultaneous nitrification and denitrification.

    PubMed

    Uemoto, H; Watanabe, A; Saitoh, S; Kondo, T; Matuki, Y; Masukawa, M; Matsumura, H; Koike, Y

    1999-12-01

    Five crucian carp, Carassius auratus langsdorfiicarps had been reared in a closed water recirculating system. The system was equipped with the compact bioreactor using the plate gels capable of both nitrification and denitrification in a single unit. Ammonia and nitrite concentrations in the rearing water had been maintained below 0.05 mg-N/L, and nitrate concentration also controlled between 2 and 8 mg-N/L with the bioreactor. As concerns nitrogen budget in the closed system, 95.0% of nitrogen income from feed was lost as nitrogen gas from the closed system. All fish was alive for 91 days without any unusual behavior. Thus, the bioreactor performed both nitrification and denitrification abilities enough to rear the five fish for 91 days. The bioreactor using the plate gels would be effective to simplify the closed system both physically and operationally, since it can remove the ammonia excreted from fish as nitrogen gas by a single step. PMID:11542800