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Sample records for aerated stirred tank

  1. Effect of aeration and agitation regimes on lipase production by newly isolated Rhodotorula mucilaginosa-MTCC 8737 in stirred tank reactor using molasses as sole production medium.

    PubMed

    Potumarthi, Ravichandra; Subhakar, Chennupati; Vanajakshi, J; Jetty, Annapurna

    2008-12-01

    The influence of media and process parameters (aeration and agitation) on fermentation broth rheology and biomass formation has been studied in 1.5-l stirred tank reactor for lipase production using Rhodotorula mucilaginosa MTCC 8737. Molasses, as sole production medium, is used for lipase production by varying aeration (1, 2, and 3 vvm) and agitation speeds (100, 200, and 300 rpm). Maximum lipase activity of 72 U/ml was obtained during 96 h of fermentation at 2 vvm, 200 rpm, pH 7, and 25 +/- 2 degrees C temperature. Lipase production kinetics with respect to dry cell weight of biomass showed Y (P/S) of 25.71 U/mg, specific product formation of 10.9 U/mg DC, and Y (X/S) 2.35 mg/mg. Maximum lipase activity (MC 2) of 56 U/ml was observed at 1% molasses, and a further increase in the molasses concentration of (%) 1.5 and 2 inhibited the product formation of lipase with 15 and 8.5 U/ml, respectively. The production kinetics of molasses media showed Y (P/X) was 14 U/mg DC, Y (P/S) 16 U/mg, and Y (X/S) 1.14 mg/mg during 96 h of bioreactor operation. The k(L)a values for all batches (MC 1-MC 4) at 96 h of fermentation were 32, 28, 21, and 19/h, and the |oxygen transfer rate were 54.4, 56, 35.7, and 17.29 mg/l h, respectively. Increase in molasses concentration resulted in decreased lipase activity by increase in viscosity of the fermentation broth.

  2. Applying fine bubble aeration to small aeration tanks.

    PubMed

    Duchène, P; Cotteux, E; Capela, S

    2001-01-01

    Because the aeration system in an activated sludge plant typically represents a large part of the total energy requirements, designers and operators need accurate oxygen transfer information to make the aeration system as energy efficient as possible. This paper presents clean water tests performed at 38 wastewater treatment plants. The Specific Aeration Efficiency results (SAE, kgO2/kWh) are reported for: (1) large open channels (volume higher than 1000 m3), (2) small open channels, (3) total floor coverage cylindrical tanks, and (4) cylindrical tanks with a grid arrangement. Some practical guidelines can be drawn, some of them being: (1) high SAE can be achieved at small aeration tanks (< 1000 m3), applying cylindrical tanks with a total floor coverage arrangement of diffusers, volumetric blowers, and moderate air flow rates per diffuser area; (2) the high investment cost of this configuration can be justified with respect to a grid layout characterized by spiral liquid circulation which affects the oxygen transfer; (3) small open channels can meet sufficient SAE values but fail to meet in this range of tank volumes those of total floor coverage cylindrical tanks.

  3. Comparison of a production process in a membrane-aerated stirred tank and up to 1000-L airlift bioreactors using BHK-21 cells and chemically defined protein-free medium.

    PubMed

    Hesse, Friedemann; Ebel, Maria; Konisch, Nadine; Sterlinski, Reinhard; Kessler, Wolfgang; Wagner, Roland

    2003-01-01

    The applicability of a protein-free medium for the production of recombinant human interleukin-2 with baby hamster kidney cells in airlift bioreactors was investigated. For this purpose, a BHK-21 cell line, adapted to grow and produce in protein-free SMIF7 medium without forming spheroids in membrane-aerated bubble-free bioreactors, was used as the producer cell line. First, cultivation of the cells was established at a 20-L scale using an internal loop airlift bioreactor system. During the culturing process the medium formulation was optimized according to the specific requirements associated with cultivation of mammalian cells under protein-free conditions in a bubble-aerated system. The effects of the addition of an antifoam agent on growth, viability, productivity, metabolic rates, and release of lactate dehydrogenase were investigated. Although it was possible to establish cultivation and production at a 20-L scale without the use of antifoaming substances, the addition of 0.002% silicon-oil-based antifoaming reagent improved the cultivation system by completely preventing foam formation. This reduced the release of lactate dehydrogenase activity to the level found in bubble-free aerated stirred tank membrane bioreactors and led to a reduction in generation doubling times by about 5 h (17%). Using the optimized medium formulation, cells were cultivated at a 1000-L scale, resulting in a culture performance comparable to the 20-L airlift bioreactor. For comparison, cultivations with protein-containing SMIF7 medium were carried out at 20- and 1000-L scales. The application of protein supplements did not lead to a significant improvement in the cultivation conditions. The results were also compared with experiments performed in a bubble-free aerated stirred tank membrane bioreactor to evaluate the influence of bubbles on the investigated culture parameters. The data implied a higher metabolic activity of the cells in airlift bioreactors with a 150% higher glucose

  4. Oxygen transfer in circular surface aeration tanks.

    PubMed

    Rao, Achanta Ramakrishna; Patel, Ajey Kumar; Kumar, Bimlesh

    2009-06-01

    Surface aeration systems employed in activated sludge plants are the most energy-intensive units of the plants and typically account for a higher percentage of the treatment facility's total energy use. The geometry of the aeration tank imparts a major effect on the system efficiency. It is said that at optimal geometric conditions, systems exhibits the maximum efficiency. Thus the quantification of the optimal geometric conditions in surface aeration tanks is needed. Optimal geometric conditions are also needed to scale up the laboratory result to the field installation. In the present work, experimental studies have been carried out on baffled and unbaffled circular surface aeration tanks to ascertain the optimal geometric conditions. It is found that no optimal geometric conditions exist for the liquid/water depth in circular surface aeration tanks; however, for design purposes, a standard value has been assumed. Based on the optimal geometric conditions, a scale-up equation has been developed for the baffled circular surface aeration tanks.

  5. Characterization of hydromechanical stress in aerated stirred tanks up to 40 m3 scale by measurement of maximum stable drop size

    PubMed Central

    2014-01-01

    Background Turbulence intensity, or hydromechanical stress, is a parameter that influences a broad range of processes in the fields of chemical engineering and biotechnology. Fermentation processes are often characterized by high agitation and aeration intensity resulting in high gas void fractions of up to 20% in large scale reactors. Very little experimental data on hydromechanical stress for such operating conditions exists because of the problems associated with measuring hydromechanical stress under aeration and intense agitation. Results An indirect method to quantify hydromechanical stress for aerated operating conditions by the measurement of maximum stable drop size in a break-up controlled dispersion was applied to characterize hydromechanical stress in reactor scales of 50 L, 3 m3 and 40 m3 volume with a broad range of operating conditions and impeller geometries (Rushton turbines). Results for impellers within each scale for the ratio of maximum to specific energy dissipation rate ϕ based on measured values of maximum stable drop size for aerated operating conditions are qualitatively in agreement with results from literature correlations for unaerated operating conditions. Comparison of data in the different scales shows that there is a scale effect that results in higher values for ϕ in larger reactors. This behavior is not covered by the classic theory of turbulent drop dispersion but is in good agreement with the theory of turbulence intermittency. The data for all impeller configurations and all aeration rates for the three scales can be correlated within ±20% when calculated values for ϕ based on the measured values for dmax are used to calculate the maximum local energy dissipation rate. A correlation of the data for all scales and all impeller configurations in the form ϕ = 2.3∙(ϕunaerated)0.34∙(DR)0.543 is suggested that successfully models the influence of scale and impeller geometry on ϕ for aerated operating conditions

  6. Adaptive Model of Wastewater Aeration Tank

    NASA Astrophysics Data System (ADS)

    Sniders, Andris; Laizans, Aigars

    2011-01-01

    The paper discusses the methodology of oxygen transfer virtual simulation in a wastewater biological treatment process, using the MATLAB/SIMULINK technology. A self-tuning adaptive model of a wastewater aeration tank, as a non-stationary object, with variable time dependent sensitivity and inertia indexes, as the functions of input variable - air pneumatic supply capacity Lg(t) (m3/min), output variable - dissolved oxygen concentration C(t) (g/m3) and oxygen expenditure, as a load - q(t) (g/min), required for wastewater complete purification, is expounded. Virtual models, applying Laplace transforms and SIMULINK blocks library, are composed in order to compare the transient processes of dissolved oxygen concentration in the simplified stationary model with constant sensitivity and inertia coefficients, and in the non-stationary model with variable sensitivity and inertia indexes. The simulation block-diagram for non-stationary model adoption to the variable parameters is developed, using informative links from input variable Lg(t), from variable load q(t) and feedback from output variable C(t) as inputs of calculation modulus, allowing to instantly re-calculate the variable indexes during simulation time. Comparison of the simplified stationary model and the non-stationary model shows that the simulation results of oxygen transfer differ up to 50%.

  7. Production of xylanolytic enzymes by Aspergillus terricola in stirred tank and airlift tower loop bioreactors.

    PubMed

    Michelin, Michele; Polizeli, Maria de Lourdes Teixeira de Moraes; Silva, Daniel Pereira da; Ruzene, Denise Santos; Vicente, António Augusto; Jorge, João Atílio; Terenzi, Héctor Francisco; Teixeira, José António

    2011-12-01

    Fungi producing high xylanase levels have attracted considerable attention because of their potential industrial applications. Batch cultivations of Aspergillus terricola fungus were evaluated in stirred tank and airlift bioreactors, by using wheat bran particles suspended in the cultivation medium as substrate for xylanase and β-xylosidase production. In the stirred tank bioreactor, in physical conditions of 30°C, 300 rpm, and aeration of 1 vvm (1 l min⁻¹), with direct inoculation of fungal spores, 7,475 U l⁻¹ xylanase was obtained after 36 h of operation, remaining constant after 24 h. In the absence of air injection in the stirred tank reactor, limited xylanase production was observed (final concentration 740 U l⁻¹). When the fermentation process was realized in the airlift bioreactor, xylanase production was higher than that observed in the stirred tank bioreactor, being 9,265 U l⁻¹ at 0.07 vvm (0.4 l min⁻¹) and 12,845 U l⁻¹ at 0.17 vvm (1 l min⁻¹) aeration rate.

  8. New milliliter-scale stirred tank bioreactors for the cultivation of mycelium forming microorganisms.

    PubMed

    Hortsch, Ralf; Stratmann, Ansgar; Weuster-Botz, Dirk

    2010-06-15

    A novel milliliter-scale stirred tank bioreactor was developed for the cultivation of mycelium forming microorganisms on a 10 milliliter-scale. A newly designed one-sided paddle impeller is driven magnetically and rotates freely on an axis in an unbaffled reaction vessel made of polystyrene. A rotating lamella is formed which spreads out along the reactor wall. Thus an enhanced surface-to-volume ratio of the liquid phase is generated where oxygen is introduced via surface aeration. Volumetric oxygen transfer coefficients (k(L)a) > 0.15 s(-1) were measured. The fast moving liquid lamella efficiently prevents wall growth and foaming. Mean power consumption and maximum local energy dissipation were measured as function of operating conditions in the milliliter-scale stirred tank bioreactor (V = 10 mL) and compared to a standard laboratory-scale stirred tank bioreactor with six-bladed Rushton turbines (V = 2,000 mL). Mean power consumption increases with increasing impeller speed and shows the same characteristics and values on both scales. The maximum local energy dissipation of the milliliter-scale stirred tank bioreactor was reduced compared to the laboratory-scale at the same mean volumetric power input. Hence the milliliter impeller distributes power more uniformly in the reaction medium. Based on these data a reliable and robust scale-up of fermentation processes is possible. This was demonstrated with the cultivation of the actinomycete Streptomyces tendae on both scales. It was shown that the process performances were equivalent with regard to biomass concentration, mannitol consumption and production of the pharmaceutical relevant fungicide nikkomycin Z up to a process time of 120 h. A high parallel reproducibility was observed on the milliliter-scale (standard deviation < 8%) with up to 48 stirred tank bioreactors operated in a magnetic inductive drive. Rheological behavior of the culture broth was measured and showed a highly viscous shear-thinning non

  9. Friction Stir Welded Thin Wall Cryogenic Tank Skins

    NASA Astrophysics Data System (ADS)

    Potter, David M.; Takeshita, Jennifer A.; Holguin, Michael J.

    2007-01-01

    A cryogenic propellant tank is the common element of trans-planetary transportation systems, in-space storage depots, lunar landers, in-space habitats/laboratories, ascent/descent, and launch vehicles. Lockheed Martin's (LM) cryogenic tank approach integrates Friction Stir Welding (FSW) with thin-gage aluminum monocoque structural design, common spin formed FSW domes and variable tank lengths to tailor the cryogenic tank from smaller stages, such as landers or ascent/descent stages, to very large on-orbit or In Space Resource Utilization (ISRU) storage systems. Thin gage corrosion resistant steel (CRES) construction combined with normal fusion welding as used on LM's Centaur has already been demonstrated to provide the highest cryogenic tank mass fraction (~.90) for large scale, cryogenic propellant storage. However, current fusion welding technology is limited by the alloys that are considered weldable and typically achieves only 50% of the parent material ultimate strength at the weld joint. Preliminary LM technology development indicates that in certain aluminum alloys, the FSW joint retains up to 100% of the parent material ultimate strength at LH2 temperatures. Combining FSW and aluminum monocoque tank design would create a large scale cryogenic tank with a mass fraction in excess of the current industry standard and therefore is ideal for affordable, reliable, high capacity propellant storage required for all facets of space exploration.

  10. Computational fluid dynamics modelling of hydraulics and sedimentation in process reactors during aeration tank settling.

    PubMed

    Jensen, M D; Ingildsen, P; Rasmussen, M R; Laursen, J

    2006-01-01

    Aeration tank settling is a control method allowing settling in the process tank during high hydraulic load. The control method is patented. Aeration tank settling has been applied in several waste water treatment plants using the present design of the process tanks. Some process tank designs have shown to be more effective than others. To improve the design of less effective plants, computational fluid dynamics (CFD) modelling of hydraulics and sedimentation has been applied. This paper discusses the results at one particular plant experiencing problems with partly short-circuiting of the inlet and outlet causing a disruption of the sludge blanket at the outlet and thereby reducing the retention of sludge in the process tank. The model has allowed us to establish a clear picture of the problems arising at the plant during aeration tank settling. Secondly, several process tank design changes have been suggested and tested by means of computational fluid dynamics modelling. The most promising design changes have been found and reported.

  11. Oxygen mass transfer in a stirred tank bioreactor using different impeller configurations for environmental purposes.

    PubMed

    Karimi, Ali; Golbabaei, Farideh; Mehrnia, Momammad Reza; Neghab, Masoud; Mohammad, Kazem; Nikpey, Ahmad; Pourmand, Mohammad Reza

    2013-01-07

    In this study, a miniature stirred tank bioreactor was designed for treatment of waste gas containing benzene, toluene and xylene. Oxygen mass transfer characteristics for various twin and single-impeller systems were investigated for 6 configurations in a vessel with 10 cm of inner diameter and working volume of 1.77L. Three types of impellers, namely, Rushton turbine, Pitched 4blades and Pitched 2blades impellers with downward pumping have been used. Deionized water was used as a liquid phase. With respect to other independent variables such as agitation speed, aeration rate, type of sparger, number of impellers, the relative performance of these impellers was assessed by comparing the values of (KLa) as a key parameter. Based on the experimental data, empirical correlations as a function of the operational conditions have been proposed, to study the oxygen transfer rates from air bubbles generated in the bioreactor. It was shown that twin Rushton turbine configuration demonstrates superior performance (23% to 77% enhancement in KLa) compared with other impeller compositions and that sparger type has negligible effect on oxygen mass transfer rate. Agitation speeds of 400 to 800 rpm were the most efficient speeds for oxygen mass transfer in the stirred bioreactor.

  12. Oxygen mass transfer in a stirred tank bioreactor using different impeller configurations for environmental purposes

    PubMed Central

    2013-01-01

    In this study, a miniature stirred tank bioreactor was designed for treatment of waste gas containing benzene, toluene and xylene. Oxygen mass transfer characteristics for various twin and single-impeller systems were investigated for 6 configurations in a vessel with 10 cm of inner diameter and working volume of 1.77L. Three types of impellers, namely, Rushton turbine, Pitched 4blades and Pitched 2blades impellers with downward pumping have been used. Deionized water was used as a liquid phase. With respect to other independent variables such as agitation speed, aeration rate, type of sparger, number of impellers, the relative performance of these impellers was assessed by comparing the values of (KLa) as a key parameter. Based on the experimental data, empirical correlations as a function of the operational conditions have been proposed, to study the oxygen transfer rates from air bubbles generated in the bioreactor. It was shown that twin Rushton turbine configuration demonstrates superior performance (23% to 77% enhancement in KLa) compared with other impeller compositions and that sparger type has negligible effect on oxygen mass transfer rate. Agitation speeds of 400 to 800 rpm were the most efficient speeds for oxygen mass transfer in the stirred bioreactor. PMID:23369581

  13. A cubic autocatalytic reaction in a continuous stirred tank reactor

    SciTech Connect

    Yakubu, Aisha Aliyu; Yatim, Yazariah Mohd

    2015-10-22

    In the present study, the dynamics of the cubic autocatalytic reaction model in a continuous stirred tank reactor with linear autocatalyst decay is studied. This model describes the behavior of two chemicals (reactant and autocatalyst) flowing into the tank reactor. The behavior of the model is studied analytically and numerically. The steady state solutions are obtained for two cases, i.e. with the presence of an autocatalyst and its absence in the inflow. In the case with an autocatalyst, the model has a stable steady state. While in the case without an autocatalyst, the model exhibits three steady states, where one of the steady state is stable, the second is a saddle point while the last is spiral node. The last steady state losses stability through Hopf bifurcation and the location is determined. The physical interpretations of the results are also presented.

  14. A cubic autocatalytic reaction in a continuous stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Yakubu, Aisha Aliyu; Yatim, Yazariah Mohd

    2015-10-01

    In the present study, the dynamics of the cubic autocatalytic reaction model in a continuous stirred tank reactor with linear autocatalyst decay is studied. This model describes the behavior of two chemicals (reactant and autocatalyst) flowing into the tank reactor. The behavior of the model is studied analytically and numerically. The steady state solutions are obtained for two cases, i.e. with the presence of an autocatalyst and its absence in the inflow. In the case with an autocatalyst, the model has a stable steady state. While in the case without an autocatalyst, the model exhibits three steady states, where one of the steady state is stable, the second is a saddle point while the last is spiral node. The last steady state losses stability through Hopf bifurcation and the location is determined. The physical interpretations of the results are also presented.

  15. Processes to improve energy efficiency during pumping and aeration of recirculating water in circular tank systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional gas transfer technologies for aquaculture systems occupy a large amount of space, require considerable capital investment, and can contribute to high electricity demand. In addition, diffused aeration in a circular tank can interfere with the hydrodynamics of water rotation and the spee...

  16. Effect of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions.

    PubMed

    Diak, James; Örmeci, Banu; Kennedy, Kevin J

    2013-04-01

    Micro-aeration, which refers to the addition of very small amounts of air, is a simple technology that can potentially be incorporated in septic tanks to improve the digestion performance. The purpose of this study was to investigate and compare the effects of micro-aeration on anaerobic digestion of primary sludge under septic tank conditions. 1.6 L batch reactor experiments were carried out in duplicate using raw primary sludge, with 4.1 % total solids, and diluted primary sludge, with 2.1 % total solids. Reactors were operated for 5 weeks at room temperature to simulate septic tank conditions. Micro-aeration rate of 0.00156 vvm effectively solubilised chemical oxygen demand (COD) and improved the subsequent degradation of COD. Micro-aeration also increased the generation of ammonia and soluble proteins, but did not improve the reduction in total and volatile solids, or the reduction in carbohydrates. Experiments using diluted sludge samples showed similar trends as the experiments with raw sludge, which suggest that initial solids concentration did not have a significant effect on the degradation of primary sludge under septic tank conditions.

  17. Process design and dynamics of a series of continuously fed aerated tank reactors treating dairy manure.

    PubMed

    Alitalo, Anni; Alakukku, Laura; Aura, Erkki

    2013-09-01

    A 6-month trial was carried out to study operational conditions and process dynamics in a system of six continuously fed aerated tank bioreactors grouped by serial connection. Feedback was with NH3-stripped solution after biological treatment, with the purpose of lowering the NH3 content of the feedback solution in order to improve the process. The fate of carbon and nutrients during treatment were determined, as well as the ammonia stripping performance of the biological treatment. The results of the study confirmed the dynamic nature of the serial system and indicated its resistance to process disturbances. The feedback of slurry resulted in a dilution effect and significantly reduced the carbon and nutrients concentrations in the first tank, increasing the treatment efficiency. Overall, after mechanical separation, low intensity aeration treatment and ammonia stripping, up to 61%, 67%, 79% and 83% average reductions of TS, Ntot, NH4(+)-N and Ptot, respectively, were reached.

  18. Growth kinetics of biopigment production by Thai isolated Monascus purpureus in a stirred tank bioreactor.

    PubMed

    Kongruang, Sasithorn

    2011-01-01

    Monascus purpureus is a biopigment-producing fungi whose pigments can be used in many biotechnological and food industries. The growth kinetics of biopigment production were investigated in a liquid fermentation medium in a 5-l stirred tank bioreactor at 30°C, pH 7, for 8 days with 100 rpm agitation and 1.38 × 10(5) N/m(2) aeration. Thai Monascus purpureus strains TISTR 3002, 3180, 3090 and 3385 were studied for color production, growth kinetics and productivity. Citrinin as a toxic metabolite was measured from the Monascus fermentation broth. The biopigment productions were detected from fermentation broth by scanning spectra of each strain produced. Results showed a mixture of yellow, orange and red pigments with absorption peaks of pigments occurring at different wavelengths for the four strains. It was found that for each pigment color, the color production from the strains increased in the order TISTR 3002, 3180, 3090, 3385 with 3385 production being approximately 10 times that of 3002. Similar results were found for growth kinetics and productivity. HPLC results showed that citrinin was not produced under the culture conditions of this study. The L*, a* and b* values of the CIELAB color system were also obtained for the yellow, orange and red pigments produced from the TISTR 3002, 3180, 3090 and 3385 strains. The colors of the pigments ranged from burnt umber to deep red.

  19. Energy-efficient stirred-tank photobioreactors for simultaneous carbon capture and municipal wastewater treatment.

    PubMed

    Mohammed, K; Ahammad, S Z; Sallis, P J; Mota, C R

    2014-01-01

    Algal based wastewater treatment (WWT) technologies are attracting renewed attention because they couple energy-efficient sustainable treatment with carbon capture, and reduce the carbon footprint of the process. A low-cost energy-efficient mixed microalgal culture-based pilot WWT system, coupled with carbon dioxide (CO2) sequestration, was investigated. The 21 L stirred-tank photobioreactors (STPBR) used light-emitting diodes as the light source, resulting in substantially reduced operational costs. The STPBR were operated at average optimal light intensity of 582.7 μmol.s(-1).m(-2), treating synthetic municipal wastewater containing approximately 250, 90 and 10 mg.L(-1) of soluble chemical oxygen demand (SCOD), ammonium (NH4-N), and phosphate, respectively. The STPBR were maintained for 64 days without oxygen supplementation, but had a supply of CO2 (25 mL.min(-1), 25% v/v in N2). Relatively high SCOD removal efficiency (>70%) was achieved in all STPBR. Low operational cost was achieved by eliminating the need for mechanical aeration, with microalgal photosynthesis providing all oxygenation. The STPBR achieved an energy saving of up to 95%, compared to the conventional AS system. This study demonstrates that microalgal photobioreactors can provide effective WWT and carbon capture, simultaneously, in a system with potential for scaling-up to municipal WWT plants.

  20. Kinetic modeling and scale up of lipoic acid (LA) production from Saccharomyces cerevisiae in a stirred tank bioreactor.

    PubMed

    Jayakar, Shilpa S; Singhal, Rekha S

    2013-08-01

    Scale up studies for production of lipoic acid (LA) from Saccharomyces cerevisiae have been reported in this paper for the first time. LA production in batch mode was carried out in a stirred tank bioreactor at varying agitation and aeration with maximum LA production of 512 mg/L obtained at 350 rpm and 25 % dissolved oxygen in batch culture conditions. Thus, LA production increased from 352 mg/L in shake flask to 512 mg/L in batch mode in a 5 L stirred tank bioreactor. Biomass production under these conditions was mathematically explained using logistic equation and data obtained for LA production and substrate utilization were successfully fitted using Luedeking-Piret and Mercier's models. The kinetic studies showed LA production to be growth associated. Further enhancement of LA production was carried out using fed-batch (variable volume) and semi-continuous modes of fermentation. Semi-continuous fermentation with three feeding cycles of sucrose effectively increased the production of LA from 512 to 725 mg/L.

  1. Modeling and simulation of large scale stirred tank

    NASA Astrophysics Data System (ADS)

    Neuville, John R.

    The purpose of this dissertation is to provide a written record of the evaluation performed on the DWPF mixing process by the construction of numerical models that resemble the geometry of this process. There were seven numerical models constructed to evaluate the DWPF mixing process and four pilot plants. The models were developed with Fluent software and the results from these models were used to evaluate the structure of the flow field and the power demand of the agitator. The results from the numerical models were compared with empirical data collected from these pilot plants that had been operated at an earlier date. Mixing is commonly used in a variety ways throughout industry to blend miscible liquids, disperse gas through liquid, form emulsions, promote heat transfer and, suspend solid particles. The DOE Sites at Hanford in Richland Washington, West Valley in New York, and Savannah River Site in Aiken South Carolina have developed a process that immobilizes highly radioactive liquid waste. The radioactive liquid waste at DWPF is an opaque sludge that is mixed in a stirred tank with glass frit particles and water to form slurry of specified proportions. The DWPF mixing process is composed of a flat bottom cylindrical mixing vessel with a centrally located helical coil, and agitator. The helical coil is used to heat and cool the contents of the tank and can improve flow circulation. The agitator shaft has two impellers; a radial blade and a hydrofoil blade. The hydrofoil is used to circulate the mixture between the top region and bottom region of the tank. The radial blade sweeps the bottom of the tank and pushes the fluid in the outward radial direction. The full scale vessel contains about 9500 gallons of slurry with flow behavior characterized as a Bingham Plastic. Particles in the mixture have an abrasive characteristic that cause excessive erosion to internal vessel components at higher impeller speeds. The desire for this mixing process is to ensure the

  2. CFD simulation of an unbaffled stirred tank reactor driven by a magnetic rod: assessment of turbulence models.

    PubMed

    Li, Jiajia; Deng, Baoqing; Zhang, Bing; Shen, Xiuzhong; Kim, Chang Nyung

    2015-01-01

    A simulation of an unbaffled stirred tank reactor driven by a magnetic stirring rod was carried out in a moving reference frame. The free surface of unbaffled stirred tank was captured by Euler-Euler model coupled with the volume of fluid (VOF) method. The re-normalization group (RNG) k-ɛ model, large eddy simulation (LES) model and detached eddy simulation (DES) model were evaluated for simulating the flow field in the stirred tank. All turbulence models can reproduce the tangential velocity in an unbaffled stirred tank with a rotational speed of 150 rpm, 250 rpm and 400 rpm, respectively. Radial velocity is underpredicted by the three models. LES model and RNG k-ɛ model predict the better tangential velocity and axial velocity, respectively. RNG k-ɛ model is recommended for the simulation of the flow in an unbaffled stirred tank with magnetic rod due to its computational effort.

  3. Biodegradation of Fresh vs. Oven-Dried Inedible Crop Residue in a Continuously Stirred Tank Reactor

    NASA Technical Reports Server (NTRS)

    Crawford, Kamau; Strayer, Richard

    1998-01-01

    The degradation of soluble organics and mineral recovery from fresh and oven-dried biomass were compared in an Intermediate-Scale Aerobic Bioreactor (8 L working volume) to determine if drying crop residue improves performance in a continuously stirred tank reactor (CSTR). The study was conducted in an Intermediate-Scale Aerobic Bioreactor (ISAB) CSTR with dimensions of 390 mm height x 204 mm diameter. The pH in the bioreactor was controlled at 6.0, temperature at 30 C, and aeration at 7.0 L/min. Gases monitored were CO2 evolution and dissolved oxygen. Homogeneously mixed wheat cultures, used either fresh or oven-dried biomass and were leached, then placed in the ISAB for a 4-day degradation period. Studies found that mineral recovery was greater for leached oven-dried crop residue. However, after activity by the mixed microbial communities in the ISAB CSTR, there were little notable differences in the measured mineral recovery and degradation of soluble organic compounds. Degradation of soluble organic compounds was also shown to improve for leached oven-dried crop residue, but after mixing in the CSTR the degradation of the fresh biomass seemed to be slightly greater. Time for the biomass to turn in the CSTR appeared to be one factor for the experimental differences between the fresh and oven-dried biomass. Other factors, although not as defined, were the differing physical structures in the cell walls and varying microbial components of the fresh and oven-dried treatments due to changes in chemical composition after drying of the biomass.

  4. Experimental Study on Scale-Up of Solid-Liquid Stirred Tank with an Intermig Impeller

    NASA Astrophysics Data System (ADS)

    Zhao, Hongliang; Zhao, Xing; Zhang, Lifeng; Yin, Pan

    2017-02-01

    The scale-up of a solid-liquid stirred tank with an Intermig impeller was characterized via experiments. Solid concentration, impeller just-off-bottom speed and power consumption were measured in stirred tanks of different scales. The scale-up criteria for achieving the same effect of solid suspension in small-scale and large-scale vessels were evaluated. The solids distribution improves if the operating conditions are held constant as the tank is scaled-up. The results of impeller just-off-bottom speed gave X = 0.868 in the scale-up relationship ND X = constant. Based on this criterion, the stirring power per unit volume obviously decreased at N = N js, and the power number ( N P) was approximately equal to 0.3 when the solids are uniformly distributed in the vessels.

  5. Loading Considerations for Implementing Friction STIR Welding for Large Diameter Tank Fabrication

    NASA Technical Reports Server (NTRS)

    Adams, Glynn

    1998-01-01

    The main objectives of the research presented here are to determine the reaction loads associated with friction stir welding (FSW) and to determine the suitability of an existing welding fixture for implementing this welding process in the fabrication of large diameter tanks. Friction stir welding is a relatively new process which is being investigated as a method for joining aluminum alloys. The aluminum-lithium alloy, Al-Li 2195, which is being used to fabricate the super-light-weight shuttle external tank has proven difficult to join using fusion techniques. Therefore, FSW and its potential applicability to joining Al-Li 2195 are of particular interest to NASA.

  6. Friction Stir Welding of Large Scale Cryogenic Tanks for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Russell, Carolyn; Ding, R. Jeffrey

    1998-01-01

    The Marshall Space Flight Center (MSFC) has established a facility for the joining of large-scale aluminum cryogenic propellant tanks using the friction stir welding process. Longitudinal welds, approximately five meters in length, have been made by retrofitting an existing vertical fusion weld system, designed to fabricate tank barrel sections ranging from two to ten meters in diameter. The structural design requirements of the tooling, clamping and travel system will be described in this presentation along with process controls and real-time data acquisition developed for this application. The approach to retrofitting other large welding tools at MSFC with the friction stir welding process will also be discussed.

  7. Effect of gradual-increasing aeration mode in an aerobic tank on nutrients' removal and functional microbial communities.

    PubMed

    Zhao, Yang-Guo; Guo, Xiaoma; She, Zonglian; Gao, Mengchun; Guo, Liang

    2016-12-30

    Different aeration rates and modes in an aerobic tank of an anaerobic/anoxic/aerobic (A(2)O) process were investigated to reveal their influence on nitrogen and phosphorus removal efficiency. Meanwhile, Illumina high-throughput sequencing of partial 16S rRNA gene of bacteria was conducted to monitor the abundance and composition of microbial communities. The results showed that higher aeration rate led to better nutrients' removal efficiency. The gradual-increasing aeration mode along the wastewater stream enhanced the contaminants' removal and the system achieved chemical oxygen demand, [Formula: see text]-N, total nitrogen (TN) removal rates of 72%, 96% and 51%, respectively. However, the gradual-decreasing or uniform aeration modes resulted in inefficient removal of TN, especially the ammonia due to low DO in the end parts of A(2)O. Microbial community analysis indicated that denitrifying phosphorus-accumulating bacteria Acinetobacter spp. were the most dominant groups under the gradual-increasing aeration mode in all tanks of the A(2)O bioreactor. Moreover, the members of genera Clostridium, Thauera and Dechloromonas also largely existed in the system. The gradual-increasing aeration mode and cooperation of different groups of bacteria made the system stable and high-performance.

  8. Optimal Impeller Clearance for a Dual Stirred Unbaffled Tank with a Concave Blade Impeller

    NASA Astrophysics Data System (ADS)

    Devi, T. T.; Kumar, B.

    2016-07-01

    An experimental investigation of unbaffled stirred tanks is carried out with the use of a dual concave blade impeller to evaluate the mass transfer coefficient, power number, and vortex depth. The effect of the impeller clearance on mass transfer is analyzed to estimate the optimal impeller clearance for lower and upper impellers. It is found that the lower impeller positioned at 0.25 of the tank diameter with the clearance between the lower and upper impellers equal to 0.38 of the tank diameter gives the maximum mass transfer coefficient. A comparison with the results for dual Rushton and Rushton-concave impellers at the optimal clearance shows that the concave-concave impellers are most efficient. The scale-up criteria for optimal, geometrically similar systems of unbaffled stirred tanks with a dual concave impeller are proposed.

  9. Oil filaments produced by an impeller in a water stirred tank

    NASA Astrophysics Data System (ADS)

    Sanjuan-Galindo, Rene; Soto, Enrique; Ascanio, Gabriel; Zenit, Roberto

    2010-11-01

    Oil dispersions in aqueous media produced in stirred tanks are part of many industrial processes. The oil drops size and dispersion stability are determined by the impeller geometry, stirring velocity and the physicochemical properties of the mixture. A critical parameter is the total interfacial area which is increased as the drop size is decreased. The mechanism that disperses the oil and generates the drops has not been completely explained. In the present work, castor oil (1% v/v, viscosity 500mPa) and water are stirred with a Scaba impeller in a flat bottom cylindrical tank. The process was recorded with high-speed video and the Reynolds number was fixed to 24,000. Before the stirring, the oil is added at the air water interface. At the beginning of the stirring, the oil is suctioned at the impeller shaft and incorporated into the flow ejected by the impeller. In this region, the flow is turbulent and exhibits velocity gradients that elongate the oil phase. Viscous thin filaments are generated and expelled from the impeller. Thereafter, the filaments are elongated and break to form drops. This process is repeated in all the oil phase and drops are incorporated into the dispersion. Two main zones can be identified in the tank: the impeller discharge characterized by high turbulence and the rest of the flow where low velocity gradients appear. In this region surface forces dominate the inertial ones, and drops became spheroidal.

  10. Drawdown of floating solids in stirred tanks: scale-up study using CFD modeling.

    PubMed

    Waghmare, Yogesh; Falk, Rick; Graham, Lisa; Koganti, Venkat

    2011-10-14

    This work shows development of a scale up correlation using computational fluid dynamic (CFD) simulations for floating solids drawdown operation in stirred tanks. Discrete phase modeling (DPM) simulations were used in conjunction with the lab scale experimental measurements to develop a semi-empirical correlation for the prediction of rate of drawdown of floating solid particles. The rate was correlated to average liquid velocity at the free liquid surface. Since, this correlation is based on a fundamental hydrodynamic parameter, velocity, rather than an operating parameters such as the impeller speed, it can be used for a variety of impeller types and tank geometries. The correlation was developed based on the data obtained from the 2L tank using four different tank designs and was validated against the data obtained from the 10L scale tank. The correlation was further extended to the pilot and the commercial scale tanks ranging from 40L to 4000L scale based solely on the CFD model.

  11. A Colorful Mixing Experiment in a Stirred Tank Using Non-Newtonian Blue Maize Flour Suspensions

    ERIC Educational Resources Information Center

    Trujilo-de Santiago, Grissel; Rojas-de Gante, Cecillia; García-Lara, Silverio; Ballesca´-Estrada, Adriana; Alvarez, Marion Moise´s

    2014-01-01

    A simple experiment designed to study mixing of a material of complex rheology in a stirred tank is described. Non-Newtonian suspensions of blue maize flour that naturally contain anthocyanins have been chosen as a model fluid. These anthocyanins act as a native, wide spectrum pH indicator exhibiting greenish colors in alkaline environments, blue…

  12. Monoterpenoid oxindole alkaloid production by Uncaria tomentosa (Willd) D.C. cell suspension cultures in a stirred tank bioreactor.

    PubMed

    Trejo-Tapia, Gabriela; Cerda-García-Rojas, Carlos M; Rodríguez-Monroy, Mario; Ramos-Valdivia, Ana C

    2005-01-01

    Cell growth, monoterpenoid oxindole alkaloid (MOA) production, and morphological properties of Uncaria tomentosa cell suspension cultures in a 2-L stirred tank bioreactor were investigated. U. tomentosa (cell line green Uth-3) was able to grow in a stirred tank at an impeller tip speed of 95 cm/s (agitation speed of 400 rpm), showing a maximum biomass yield of 11.9 +/- 0.6 g DW/L and a specific growth rate of 0.102 d(-1). U. tomentosa cells growing in a stirred tank achieved maximum volumetric and specific MOA concentration (467.7 +/- 40.0 microg/L, 44.6 +/- 5.2 microg/g DW) at 16 days of culture. MOA chemical profile of cell suspension cultures growing in a stirred tank resembled that of the plant. Depending on culture time, from the total MOA produced, 37-100% was found in the medium in the bioreactor culture. MOA concentration achieved in a stirred tank was up to 10-fold higher than that obtained in Erlenmeyer flasks (agitated at 110 rpm). In a stirred tank, average area of the single cells of U. tomentosa increased up to 4-fold, and elliptical form factor increased from 1.40 to 2.55, indicating enlargement of U. tomentosa single cells. This work presents the first report of U. tomentosa green cell suspension cultures that grow and produce MOA in a stirred tank bioreactor.

  13. 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...

  14. Biological treatment of sewage treatment plant sludge by pure bacterial culture with optimum process conditions in a stirred tank bioreactor.

    PubMed

    Alam, M Z; Muyibi, Suleyman A; Jamal, P

    2007-09-01

    Biological treatment of sewage treatment plant (STP) sludge by potential pure bacterial culture (Bacillus sp.) with optimum process conditions for effective biodegradation and bioseparation was carried out in the laboratory. The effective and efficient bioconversion was evaluated with the treatment of pure bacterial culture and existing microbes (uninnoculated) in sludge. The optimum process conditions i.e., temperature, 40 degrees C; pH, 6; inoculum, 5% (v/v); aeration, 1 vvm; agitation speed, 50 rpm obtained from the previous studies with chemical oxygen demand COD at 30 mgL(-1) were applied for the biological treatment of sludge. The results indicated that pure bacterial culture (Bacillus sp.) showed higher degradation and separation of treated sludge compared to treatment with the existing mixed microbes in a stirred tank bioreactor. The treated STP sludge by potential pure bacterial culture and existing microbes gave 30% and 11%; 91.2% and 59.1; 88.5% and 52.3%; 98.4% and 51.3%; 96.1% and 75.2%; 99.4% and 72.8% reduction of total suspended solids (TSS, biosolids), COD, soluble protein, turbidity, total dissolved solids (TDS) and specific resistance to filtration (SRF), respectively within 7 days of treatment. The pH was observed at 6.5 and 4 during the treatment of sludge by pure culture and existing microbes, respectively.

  15. In situ investigation of tubular microbial fuel cells deployed in an aeration tank at a municipal wastewater treatment plant.

    PubMed

    Zhang, Fei; Ge, Zheng; Grimaud, Julien; Hurst, Jim; He, Zhen

    2013-05-01

    To examine the feasibility of integrating microbial fuel cells (MFCs) into an activated sludge process, three MFCs with different ion exchange membranes and/or cathode catalysts were installed in an aeration tank to treat primary effluent. Both contaminant treatment and electricity generation were studied during the operation for more than 400 days. The effects of membrane/catalysts on MFC performance were not observed, likely due to the low removal of chemical oxygen demand (COD) (<53%) caused by low electricity generation. The MFCs did not achieve any obvious removal of nutrients. The produced energy was lower than the theoretic energy consumption. The performance was seriously affected by cathode biofouling, variation of wastewater quality, and other operating conditions. Unlike prior lab studies by others, the results of this study suggest that MFCs may not be suitable for deployment in an aeration tank, unless the key problems such as biofouling are solved.

  16. Friction-Stir Welding of Large Scale Cryogenic Fuel Tanks for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Jones, Clyde S., III; Venable, Richard A.

    1998-01-01

    The Marshall Space Flight Center has established a facility for the joining of large-scale aluminum-lithium alloy 2195 cryogenic fuel tanks using the friction-stir welding process. Longitudinal welds, approximately five meters in length, were made possible by retrofitting an existing vertical fusion weld system, designed to fabricate tank barrel sections ranging from two to ten meters in diameter. The structural design requirements of the tooling, clamping and the spindle travel system will be described in this paper. Process controls and real-time data acquisition will also be described, and were critical elements contributing to successful weld operation.

  17. Bistability in an uncatalyzed bromate oscillator in a continuously fed stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Dutt, Arun K.; Müller, S. C.

    1996-01-01

    Uncatalyzed gallic acid oscillating system has been investigated in a continuously fed stirred tank reactor (CSTR). In the [Bromate]0-[Bromide]0 concentration space, a region has been located where a bistability is observed between an oscillatory branch and a flow branch. To our knowledge this is the first evidence of bistability in an uncatalyzed bromate oscillator. Some observations have been explained in terms of the skeleton mechanism proposed in the past.

  18. Growth and production of microencapsulated recombinant CHO in a stirred tank bioreactor.

    PubMed

    Wang, Yu; Zhang, Ying; Li, Na; Chen, Li; Zhang, Demeng; Sun, Dongsheng; Lv, Guojun; Yu, Weiting; Guo, Xin; Ma, Xiaojun

    2015-07-01

    Microencapsulation supplies cells with a three-dimensional microenvironment enhancing the metabolic activity, cell density and recombinant protein expression in a stirred tank bioreactor which is used widely to culture mammalian cells in many biochemical processes. In this paper, we address the growth and Desmodus rotundus salivary plasminogen activator (DSPA) production of recombinant CHO (rCHO) in a stirred tank bioreactor. Cells were cultured using two different methods--in an unmicroencapsulated versus microencapsulated culture--and compared differences between them in terms of cell reproduction and DSPA protein productivity. Compared to the unmicroencapsulated rCHO, microencapsulated cells got higher cell density and prolonged the plateau phase. Microencapsulated rCHO promoted DSPA production, with a maximum rate that was 4.8 times higher than in unmicroencapsulated cells, and the accumulated production of DSPA was 3.3 higher than in unmicroencapsulated cells. Negative relationship was found between specific growth rate and DSPA production capacity of unit cells. These findings will facilitate the methods for higher DSPA production in stirred tank bioreactors.

  19. Continuous production of diatom Entomoneis sp. in mechanically stirred tank and flat-panel airlift photobioreactors.

    PubMed

    Viriyayingsiri, Thunyaporn; Sittplangkoon, Pantaporn; Powtongsook, Sorawit; Nootong, Kasidit

    2016-10-02

    Continuous production of diatom Entomonies sp. was performed in mechanically stirred tank and flat-panel airlift photobioreactors (FPAP). The maximum specific growth rate of diatom from the batch experiment was 0.98 d(-1). A series of dilution rate and macronutrient concentration adjustments were performed in a stirred tank photobioreactor and found that the dilution rate ranged from 0.7 to 0.8 d(-1) and modified F/2 growth media containing nitrate at 3.09 mg N/L, phosphate at 2.24 mg P/L, and silicate at 11.91 mg Si/L yielded the maximum cell number density. Finally, the continuous cultivation of Entomonies sp. was conducted in FPAP using the optimal conditions determined earlier, resulting in the maximum cell number density of 19.69 × 10(4) cells/mL, which was approximately 47 and 73% increase from the result using the stirred tank photobioreactor fed with modified and standard F/2 growth media, respectively.

  20. Continuous-flow stirred-tank reactor 20-L demonstration test: Final report

    SciTech Connect

    Lee, D.D.; Collins, J.L.

    2000-02-01

    One of the proposed methods of removing the cesium, strontium, and transuranics from the radioactive waste storage tanks at Savannah River is the small-tank tetraphenylborate (TPB) precipitation process. A two-reactor-in-series (15-L working volume each) continuous-flow stirred-tank reactor (CSTR) system was designed, constructed, and installed in a hot cell to test the Savannah River process. The system also includes two cross-flow filtration systems to concentrate and wash the slurry produced in the process, which contains the bulk of radioactivity from the supernatant processed through the system. Installation, operational readiness reviews, and system preparation and testing were completed. The first test using the filtration systems, two CSTRs, and the slurry concentration system was conducted over a 61-h period with design removal of Cs, Sr, and U achieved. With the successful completion of Test 1a, the following tests, 1b and 1c, were not required.

  1. High cell density cultivation of recombinant yeasts and bacteria under non-pressurized and pressurized conditions in stirred tank bioreactors.

    PubMed

    Knoll, Arnd; Bartsch, Stefan; Husemann, Bernward; Engel, Philip; Schroer, Kirsten; Ribeiro, Betina; Stöckmann, Christoph; Seletzky, Juri; Büchs, Jochen

    2007-10-31

    This study demonstrates the applicability of pressurized stirred tank bioreactors for oxygen transfer enhancement in aerobic cultivation processes. The specific power input and the reactor pressure was employed as process variable. As model organism Escherichia coli, Arxula adeninivorans, Saccharomyces cerevisiae and Corynebacterium glutamicum were cultivated to high cell densities. By applying specific power inputs of approx. 48kWm(-3) the oxygen transfer rate of a E. coli culture in the non-pressurized stirred tank bioreactor was lifted up to values of 0.51moll(-1)h(-1). When a reactor pressure up to 10bar was applied, the oxygen transfer rate of a pressurized stirred tank bioreactor was lifted up to values of 0.89moll(-1)h(-1). The non-pressurized stirred tank bioreactor was able to support non-oxygen limited growth of cell densities of more than 40gl(-1) cell dry weight (CDW) of E. coli, whereas the pressurized stirred tank bioreactor was able to support non-oxygen limited growth of cell densities up to 225gl(-1) CDW of A. adeninivorans, 89gl(-1) CDW of S. cerevisiae, 226gl(-1) CDW of C. glutamicum and 110gl(-1) CDW of E. coli. Compared to literature data, some of these cell densities are the highest values ever achieved in high cell density cultivation of microorganisms in stirred tank bioreactors. By comparing the specific power inputs as well as the k(L)a values of both systems, it is demonstrated that only the pressure is a scaleable tool for oxygen transfer enhancement in industrial stirred tank bioreactors. Furthermore, it was shown that increased carbon dioxide partial pressures did not remarkably inhibit the growth of the investigated model organisms.

  2. Fluid dynamic analysis of a continuous stirred tank reactor for technical optimization of wastewater digestion.

    PubMed

    Hurtado, F J; Kaiser, A S; Zamora, B

    2015-03-15

    Continuous stirred tank reactors (CSTR) are widely used in wastewater treatment plants to reduce the organic matter and microorganism present in sludge by anaerobic digestion. The present study carries out a numerical analysis of the fluid dynamic behaviour of a CSTR in order to optimize the process energetically. The characterization of the sludge flow inside the digester tank, the residence time distribution and the active volume of the reactor under different criteria are determined. The effects of design and power of the mixing system on the active volume of the CSTR are analyzed. The numerical model is solved under non-steady conditions by examining the evolution of the flow during the stop and restart of the mixing system. An intermittent regime of the mixing system, which kept the active volume between 94% and 99%, is achieved. The results obtained can lead to the eventual energy optimization of the mixing system of the CSTR.

  3. Friction-Stir-Welded and Spin-Formed End Domes for Cryogenic Tanks

    NASA Technical Reports Server (NTRS)

    Hales, S. J.; Tayon, W. A.; Domack, M. S.

    2012-01-01

    Manufacturing of single-piece end domes for cryogenic tanks employing spin forming of tailored, friction-stir-welded blanks of Al-Li alloy 2195 plate offers cost and reliability benefits. The introduction of plastic deformation into a friction stir weld is a unique feature of the proposed manufacturing route. This investigation addressed abnormal grain growth [AGG] within the friction stir weldments during postfabrication processing of a prototype dome. The phenomenon of AGG was observed during the solution heat treatment [SHT] phase of T8 tempering and is a major concern for meeting specifications. Such abrupt microstructural transitions can be detrimental to notch-sensitive mechanical properties, such as ductility and/or fracture toughness. If the issue of AGG cannot be resolved, then the acceptance of this approach as a viable manufacturing route may be in jeopardy. The innovative approach adopted in this investigation was the insertion of a stand-alone, Intermediate Annealing Treatment [IAT] between the spin forming and T8 processing operations. A simple, recovery annealing step was deemed to be the most readily-scalable solution when fabricating thin-walled, ellipsoidal domes. The research effort culminated in the development of an effective IAT, which resulted in a significant decrease in AGG following SHT. The processing philosophy adopted in designing the IAT is outlined and the microstructural reasons for success are discussed. The analytical results presented are consistent with promoting continuous grain growth during the IAT, thereby suppressing AGG during the SHT.

  4. The cumulative and sublethal effects of turbulence on erythrocytes in a stirred-tank model.

    PubMed

    Aziz, Abdulhameed; Werner, Brian C; Epting, Kevin L; Agosti, Christopher D; Curtis, Wayne R

    2007-12-01

    Mechanical forces generated by prosthetic heart devices (artificial valves, artificial hearts, ventricular assist devices) have been known to cause damage and destruction of erythrocytes. Turbulent flow within such devices generates shear stresses and can induce cell damage. Current models of cell damage rate utilize only the power input per unit mass as a modeling parameter. A stirred-tank reactor provides for a more extensive characterization of turbulence through eddy scale calculations. Through a simplified model, turbulence can be characterized by evaluating the Kolmogorov microscale. Our analysis of erythrocyte rupture in a stirred tank reactor suggests that parameters such as eddy wavelength and eddy velocity may better characterize and model the turbulent damage. Further, hemolysis of red blood cells by turbulent effects has been shown to have a fixed rate for constant levels of power input. Damage inflicted on the remaining, intact erythrocytes (sublethal damage) was evaluated by exposure to turbulence followed by osmotic fragility (OF) testing. Logistic models were fit to the OF data indicating a significant osmotic sensitivity in the sublethal damaged population between control and turbulence-exposed cells (chi(2) test; p < 0.001). This susceptibility indicates a significant cell population more susceptible to destruction as a result of turbulent exposure. This work has therefore helped identify optimization parameters for evaluating cell damage potential when engineering cardiovascular prosthetic devices.

  5. Effects of baffle configuration and tank size on spherical agglomerates of dimethyl fumarate in a common stirred tank.

    PubMed

    Lin, Po Yen; Lee, Hung Lin; Chen, Chih Wei; Lee, Tu

    2015-11-30

    To pave the way for technology transfer and scale up of the spherical agglomeration (SA) process for dimethyl fumarate, effects of the US, European and Kawashima type baffles and 0.5, 2.0 and 10 L-sized common stirred tank were studied. It was found that the particle size distribution varied significantly. However, the size-related properties such as dissolution profile and flowability of agglomerates from the same size cut after sieving could remain unchanged. The interior structure-related properties such as particle density and mechanical property of agglomerates upon baffle change and scale up from the same size cut were decayed and the agglomerates could become denser and stronger by prolonged maturation time. To maintain the same size distribution, agglomerates from any batch could have been separated and classified by sieving and then blended back together artificially by the desired weight% of each cut.

  6. Using spatio-temporal asymmetry to enhance mixing in chaotic flows: From maps to stirred tanks

    NASA Astrophysics Data System (ADS)

    Alvarez, Mario Moises

    Under laminar flow conditions, chaos is the only route to achieve effective mixing. Indeed, industrially relevant devices such as static mixers, stirred tanks, and roller bottles work because they create chaotic flows. However, they are generally operated and designed in a symmetric fashion (e.g. symmetric construction, periodic operation). Under such circumstances, chaotic and nonchaotic regions always co-exist, often hindering mixing performance. The introduction of asymmetries (in space or time) has been proposed as a means to improve mixing performance by generating globally chaotic systems in which the entire flow domain is subject to the action of exponential stretching and repeated folding, key features of chaotic flows capable of good mixing. Here we compare mixing performance of symmetric and asymmetric mixing flows from the point of view of the properties of the structure that they generate. In particular, we analyze two classes of systems: We use computer simulations to follow the process of elongation and deformation of interfaces as they are advected by time-periodic and aperiodic protocols in an idealized 2-D flow (the sine flow). The distribution of length scales characteristic of the partially mixed structures in this flow is calculated and their statistical properties are investigated. As the main conclusion, we find that the distribution of length scales is universal (independently on the periodic or aperiodic nature of the flow), and predictable (based on stretching calculations) for any globally chaotic flow. Subsequently, mixing structures and flow patterns in stirred tank systems of geometries encountered in engineering practice and operated in the laminar regime are investigated experimentally using UV visualization techniques, Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (p-LIF). It is experimentally demonstrated that concentric stirred tank configurations achieve partial chaos only by virtue of the small

  7. Lycopene production from synthetic medium by Blakeslea trispora NRRL 2895 (+) and 2896 (-) in a stirred-tank fermenter.

    PubMed

    Liu, Xiu-Ji; Liu, Rui-Sang; Li, Hong-Mei; Tang, Ya-Jie

    2012-06-01

    The dissolved oxygen tension of 20% of air saturation, pH-shift from 4.0 to 5.5 on day 3, and a moderate shear stress (calculated as an impeller tip speed, V(tip) = 0.926 - 2.161 m/s) were identified to be the key factors in scaling-up the mated fermentation of Blakeslea trispora NRRL 2895 (+) and 2896 (-) for lycopene production from a shake flask to a stirred-tank fermenter. The maximal lycopene production of 183.3 mg/L was obtained in 7.5-L stirred-tank fermenter, and then the mated fermentation process was successfully step-wise scaled-up from 7.5- to 200-L stirred-tank fermenter. The comparability of the fermentation process was well controlled and the lycopene production was maintained during the process scale-up. Furthermore, with the integrated addition of 150 μmol/L abscisic acid on day 3, 0.5 g/L leucine and 0.1 g/L penicillin on day 4, the highest lycopene production of 270.3 mg/L was achieved in the mated fermentation of B. trispora in stirred-tank fermenter.

  8. High-performance recombinant protein production with Escherichia coli in continuously operated cascades of stirred-tank reactors.

    PubMed

    Schmideder, Andreas; Weuster-Botz, Dirk

    2017-03-01

    The microbial expression of intracellular, recombinant proteins in continuous bioprocesses suffers from low product concentrations. Hence, a process for the intracellular production of photoactivatable mCherry with Escherichia coli in a continuously operated cascade of two stirred-tank reactors was established to separate biomass formation (first reactor) and protein expression (second reactor) spatially. Cascades of miniaturized stirred-tank reactors were implemented, which enable the 24-fold parallel characterization of cascade processes and the direct scale-up of results to the liter scale. With PAmCherry concentrations of 1.15 g L(-1) cascades of stirred-tank reactors improved the process performance significantly compared to production processes in chemostats. In addition, an optimized fed-batch process was outperformed regarding space-time yield (149 mg L(-1) h(-1)). This study implicates continuous cascade processes to be a promising alternative to fed-batch processes for microbial protein production and demonstrates that miniaturized stirred-tank reactors can reduce the timeline and costs for cascade process characterization.

  9. CFD optimization of continuous stirred-tank (CSTR) reactor for biohydrogen production.

    PubMed

    Ding, Jie; Wang, Xu; Zhou, Xue-Fei; Ren, Nan-Qi; Guo, Wan-Qian

    2010-09-01

    There has been little work on the optimal configuration of biohydrogen production reactors. This paper describes three-dimensional computational fluid dynamics (CFD) simulations of gas-liquid flow in a laboratory-scale continuous stirred-tank reactor used for biohydrogen production. To evaluate the role of hydrodynamics in reactor design and optimize the reactor configuration, an optimized impeller design has been constructed and validated with CFD simulations of the normal and optimized impeller over a range of speeds and the numerical results were also validated by examination of residence time distribution. By integrating the CFD simulation with an ethanol-type fermentation process experiment, it was shown that impellers with different type and speed generated different flow patterns, and hence offered different efficiencies for biohydrogen production. The hydrodynamic behavior of the optimized impeller at speeds between 50 and 70 rev/min is most suited for economical biohydrogen production.

  10. Biohydrogen production from waste bread in a continuous stirred tank reactor: A techno-economic analysis.

    PubMed

    Han, Wei; Hu, Yun Yi; Li, Shi Yi; Li, Fei Fei; Tang, Jun Hong

    2016-12-01

    Biohydrogen production from waste bread in a continuous stirred tank reactor (CSTR) was techno-economically assessed. The treating capacity of the H2-producing plant was assumed to be 2 ton waste bread per day with lifetime of 10years. Aspen Plus was used to simulate the mass and energy balance of the plant. The total capital investment (TCI), total annual production cost (TAPC) and annual revenue of the plant were USD931020, USD299746/year and USD639920/year, respectively. The unit hydrogen production cost was USD1.34/m(3) H2 (or USD14.89/kg H2). The payback period and net present value (NPV) of the plant were 4.8years and USD1266654, respectively. Hydrogen price and operators cost were the most important variables on the NPV. It was concluded that biohydrogen production from waste bread in the CSTR was feasible for practical application.

  11. Thermodynamics of open nonlinear systems far from equilibrium: The continuously stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Yoshida, Nobuo

    1993-11-01

    A thermodynamic analysis is made of a continuously stirred tank reactor (CSTR) which is fed with ideal gases and in which arbitrary types of chemical reactions take place. For stationary states and oscillatory ones in which limit cycles are established, expressions are derived which describe the change of entropy of the reactor contents relative to the feed in terms of explicit quantities, including the rate of entropy production due to the chemical reactions. This entropy change is shown to be always greater than what would be observed in closed systems under comparable circumstances. It is pointed out that this statement is beyond what the second law of thermodynamics can predict. In previous articles, entropy and entropy production have been found to follow certain systematic trends in some specific models based on the CSTR. That work is compared with the present theory.

  12. Effect of inoculation process on lycopene production by Blakeslea trispora in a stirred-tank reactor.

    PubMed

    Wang, Qiang; Feng, Ling-Ran; Luo, Wei; Li, Han-Guang; Zhou, Ya; Yu, Xiao-Bin

    2015-01-01

    Lycopene biosynthesis by Blakeslea trispora was greatly enhanced in a stirred-tank reactor when a nonsynchronous inoculation process, in which the (+) mating type was inoculated after the (-) mating type has been grown for a certain period of time, was applied. The lycopene concentration with nonsynchronous inoculation in a 24-h inoculation interval was 33 % higher than that with synchronous inoculation. The optimum inoculation ratio was 1:2 (+/-) at the 36 and 48 h inoculum age of mating types (+) and (-), respectively. Fermentation time for the individual strains and mated conditions showed that the (+) mating type grows faster than the (-) mating type. Morphological observation showed that the mycelium ratio of B. trispora (-) in mating culture with nonsynchronous inoculation was higher than that with synchronous inoculation. The results indicated that nonsynchronous inoculation process increased the dominance of B. trispora (-) in joint cultivation and hence stimulated lycopene biosynthesis.

  13. Nonlinear versus Ordinary Adaptive Control of Continuous Stirred-Tank Reactor

    PubMed Central

    Vojtesek, Jiri; Dostal, Petr

    2015-01-01

    Unfortunately, the major group of the systems in industry has nonlinear behavior and control of such processes with conventional control approaches with fixed parameters causes problems and suboptimal or unstable control results. An adaptive control is one way to how we can cope with nonlinearity of the system. This contribution compares classic adaptive control and its modification with Wiener system. This configuration divides nonlinear controller into the dynamic linear part and the static nonlinear part. The dynamic linear part is constructed with the use of polynomial synthesis together with the pole-placement method and the spectral factorization. The static nonlinear part uses static analysis of the controlled plant for introducing the mathematical nonlinear description of the relation between the controlled output and the change of the control input. Proposed controller is tested by the simulations on the mathematical model of the continuous stirred-tank reactor with cooling in the jacket as a typical nonlinear system. PMID:26346878

  14. Performance of continuous stirred tank reactor (CSTR) on fermentative biohydrogen production from melon waste

    NASA Astrophysics Data System (ADS)

    Cahyari, K.; Sarto; Syamsiah, S.; Prasetya, A.

    2016-11-01

    This research was meant to investigate performance of continuous stirred tank reactor (CSTR) as bioreactor for producing biohydrogen from melon waste through dark fermentation method. Melon waste are commonly generated from agricultural processing stages i.e. cultivation, post-harvesting, industrial processing, and transportation. It accounted for more than 50% of total harvested fruit. Feedstock of melon waste was fed regularly to CSTR according to organic loading rate at value 1.2 - 3.6 g VS/ (l.d). Optimum condition was achieved at OLR 2.4 g VS/ (l.d) with the highest total gas volume 196 ml STP. Implication of higher OLR value is reduction of total gas volume due to accumulation of acids (pH 4.0), and lower substrate volatile solid removal. In summary, application of this method might valorize melon waste and generates renewable energy sources.

  15. Bio-hydrogen production from molasses by anaerobic fermentation in continuous stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Han, Wei; Li, Yong-feng; Chen, Hong; Deng, Jie-xuan; Yang, Chuan-ping

    2010-11-01

    A study of bio-hydrogen production was performed in a continuous flow anaerobic fermentation reactor (with an available volume of 5.4 L). The continuous stirred tank reactor (CSTR) for bio-hydrogen production was operated under the organic loading rates (OLR) of 8-32 kg COD/m3 reactor/d (COD: chemical oxygen demand) with molasses as the substrate. The maximum hydrogen production yield of 8.19 L/d was obtained in the reactor with the OLR increased from 8 kg COD/m3 reactor/d to 24 kg COD/m3 d. However, the hydrogen production and volatile fatty acids (VFAs) drastically decreased at an OLR of 32 kg COD/m3 reactor/d. Ethanoi, acetic, butyric and propionic were the main liquid fermentation products with the percentages of 31%, 24%, 20% and 18%, which formed the mixed-type fermentation.

  16. Ozone degradation of alkylbenzene sulfonate in aqueous solutions using a stirred tank reactor with recirculation.

    PubMed

    Jurado-Alameda, Encarnación; Vicaria, José M; Altmajer-Vaz, Deisi; Luzón, Germán; Jiménez-Pérez, José L; Moya-Ramírez, Ignacio

    2012-01-01

    The degradation of linear alkylbenzene sulfonates (LAS) in aqueous solutions by ozone has been investigated. The ozonation process was performed in a stirred tank reactor with recirculation which simulates the clean-in-place process used in many industrial facilities. The gas-liquid mass transfer of ozone in a buffer solution at different temperatures (25-55°C) was also studied in the same device, revealing that ozone decomposition can be considered negligible under the experimental conditions assayed. The effect of the initial LAS concentration, temperature, and ozone concentration on the concentration of homologues and total LAS were analysed as a function of time. Both concentrations diminished with time, this effect being more significant when higher temperatures were assayed. The relative proportion of homologues shows that the homologues of higher chain length are degraded in a greater proportion than are the homologues with shorter chain lengths.

  17. Anaerobic digestion performance of vinegar residue in continuously stirred tank reactor.

    PubMed

    Li, Lin; Feng, Lu; Zhang, Ruihong; He, Yanfeng; Wang, Wen; Chen, Chang; Liu, Guangqing

    2015-06-01

    Anaerobic digestion (AD) of vinegar residue was investigated in continuously stirred tank reactor (CSTR). The influence of organic loading rate (OLR) and effluent recirculation on AD performance of vinegar residue was tested. Five OLRs, 1.0, 1.5, 2.0, 2.5, and 3.0 g(vs) L(-1) d(-1), were used. The highest volumetric methane productivity of 581.88 mL L(-1) was achieved at OLR of 2.5 g(vs) L(-1) d(-1). Effluent reflux ratio was set as 50%, the results showed that effluent recirculation could effectively neutralize the acidity of vinegar residue, raise the pH of the feedstock, and enhance the buffering capacity of the AD system. Anaerobic digestion of vinegar residue could be a promising way not only for converting this waste into gas energy but also alleviating environmental pollution which might be useful for future industrial application.

  18. Sidewall-box airlift pump provides large flows for aeration, CO2 stripping, and water rotation in large dual-drain circular tanks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional gas transfer technologies for aquaculture systems occupy a large amount of space, require a considerable capital investment, and can contribute to high electricity demand. In addition, diffused aeration in a circular culture tank can interfere with the hydrodynamics of water rotation a...

  19. Azadirachtin production by hairy root cultivation of Azadirachta indica in a modified stirred tank reactor.

    PubMed

    Srivastava, Smita; Srivastava, A K

    2012-11-01

    Present investigation involves hairy root cultivation of Azadirachta indica in a modified stirred tank reactor under optimized culture conditions for maximum volumetric productivity of azadirachtin. The selected hairy root line (Az-35) was induced via Agrobacterium rhizogenes LBA 920-mediated transformation of A. indica leaf explants (Coimbatore variety, India). Liquid culture of the hairy roots was developed in a modified Murashige and Skoog medium (MM2). To further enhance the productivity of azadirachtin, selected growth regulators (1.0 mg/l IAA and 0.025 mg/l GA(3)), permeabilizing agent (0.5 % v/v DNBP), a biotic elicitor (1 % v/v Curvularia (culture filtrate)) and an indirectly linked biosynthetic precursor (50 mg/l cholesterol) were added in the growth medium on 15th day of the hairy root cultivation period in shake flask. Highest azadirachtin production (113 mg/l) was obtained on 25th day of the growth cycle with a biomass of 21 g/l DW. Further, batch cultivation of hairy roots was carried out in a novel liquid-phase bioreactor configuration (modified stirred tank reactor with polyurethane foam as root support) to investigate the possible scale-up of the established A. indica hairy root culture. A biomass production of 15.2 g/l with azadirachtin accumulation in the hairy roots of 6.4 mg/g (97.28 mg/l) could be achieved after 25 days of the batch cultivation period, which was ~27 and ~14 % less biomass and azadirachtin concentration obtained respectively, in shake flasks. An overall volumetric productivity of 3.89 mg/(l day) of azadirachtin was obtained in the bioreactor.

  20. CONTINUOSLY STIRRED TANK REACTOR PARAMETERS THAT AFFECT SLUDGE BATCH 6 SIMULANT PROPERTIES

    SciTech Connect

    Newell, J.; Lambert, D.; Stone, M.; Fernandez, A.

    2010-05-28

    The High Level Radioactive Waste (HLW) Sludge in Savannah River Site (SRS) waste tanks was produced over a period of over 60 years by neutralizing the acidic waste produced in the F and H Separations Canyons with sodium hydroxide. The HLW slurries have been stored at free hydroxide concentrations above 1 M to minimize the corrosion of the carbon steel waste tanks. Sodium nitrite is periodically added as a corrosion inhibitor. The resulting waste has been subjected to supernate evaporation to minimize the volume of the stored waste. In addition, some of the waste tanks experienced high temperatures so some of the waste has been at elevated temperatures. Because the waste is radioactive, the waste is transforming through the decay of shorter lived radioactive species and the radiation damage that the decay releases. The goal of the Savannah River National Laboratory (SRNL) simulant development program is to develop a method to produce a sludge simulant that matches both the chemical and physical characteristics of the HLW without the time, temperature profile, chemical or radiation exposure of that of the real waste. Several different approaches have been taken historically toward preparing simulated waste slurries. All of the approaches used in the past dozen years involve some precipitation of the species using similar chemistry to that which formed the radioactive waste solids in the tank farm. All of the approaches add certain chemical species as commercially available insoluble solid compounds. The number of species introduced in this manner, however, has varied widely. All of the simulant preparation approaches make the simulated aqueous phase by adding the appropriate ratios of various sodium salts. The simulant preparation sequence generally starts with an acidic pH and ends up with a caustic pH (typically in the 10-12 range). The current method for making sludge simulant involves the use of a temperature controlled continuously stirred tank reactor (CSTR

  1. Study on Influence Caused by Design and Operation Factors of Contact Aeration Tank on Effluent ATU-BOD·N-BOD Concentrations from Sedimentation Tank in Rural Sewerage Facilities with Biofilm Processes

    NASA Astrophysics Data System (ADS)

    Nakano, Takuji

    The design and operation factors on the effluent ATU-BOD·N-BOD concentrations in sedimentation tank were investigated by using observed data in the rural sewerage facilities with biofilm processes. It was found that the effluent N-BOD accounted for approximate 50 percent of the effluent BOD concentration in sedimentation tank because of the effluent ATU-BOD decrease(about 70 percent) and the effluent N-BOD increase (about 4 times) by treatment processes of contact aeration tank. It was recognized that the effluent ATU-BOD concentration in sedimentation tank was influenced by the design and operation factors such as influent ATU-BOD concentration, specific surface area of contact filter for fixed bed submerged filter, and average DO in contact aeration tank. The effluent ATU-BOD concentration in sedimentation tank was assumed to be governed by first-order function with complete-mix system of biological treatment processes. The effluent ATU-BOD concentration in sedimentation tank was found to be predicted by the empirical formula of hydraulic retention time, influent ATU-BOD concentration, specific surface area of contact filter for fixed bed submerged filter, and average DO in contact aeration tank. It was recognized that the peak effluent N-BOD concentration in sedimentation tank occurred in the around 10∼15 hour of hydraulic retention time under the influence of biological nitrification reaction and nitrogenous compound. The effluent N-BOD concentration in sedimentation tank was also influenced by the effluent SS concentration in sedimentation tank.

  2. Improving the production yield and productivity of 1,3-dihydroxyacetone from glycerol fermentation using Gluconobacter oxydans NL71 in a compressed oxygen supply-sealed and stirred tank reactor (COS-SSTR).

    PubMed

    Zhou, Xin; Zhou, Xuelian; Xu, Yong; Yu, Shiyuan

    2016-08-01

    In this study, a compressed oxygen gas supply was connected to a sealed aerated stirred tank reactor (COS-SSTR) bio-system, leading to a high-oxygen pressure bioreactor used to improve the bio-transformative performance in the production of 1,3-dihydroxyacetone (DHA) from glycerol using Gluconobacter oxydans NL71. A concentration of 301.2 ± 8.2 g L(-1) DHA was obtained from glycerol after 32 h of fed-batch fermentation in the COS-SSTR system. The volumetric productivity for this process was 9.41 ± 0.23 g L(-1) h(-1), which is presently the highest obtained level of glycerol bioconversion into DHA. These results show that the application of this bioreactor would enable microbial production of DHA from glycerol at the industrial scale.

  3. A novel milliliter-scale chemostat system for parallel cultivation of microorganisms in stirred-tank bioreactors.

    PubMed

    Schmideder, Andreas; Severin, Timm Steffen; Cremer, Johannes Heinrich; Weuster-Botz, Dirk

    2015-09-20

    A pH-controlled parallel stirred-tank bioreactor system was modified for parallel continuous cultivation on a 10 mL-scale by connecting multichannel peristaltic pumps for feeding and medium removal with micro-pipes (250 μm inner diameter). Parallel chemostat processes with Escherichia coli as an example showed high reproducibility with regard to culture volume and flow rates as well as dry cell weight, dissolved oxygen concentration and pH control at steady states (n=8, coefficient of variation <5%). Reliable estimation of kinetic growth parameters of E. coli was easily achieved within one parallel experiment by preselecting ten different steady states. Scalability of milliliter-scale steady state results was demonstrated by chemostat studies with a stirred-tank bioreactor on a liter-scale. Thus, parallel and continuously operated stirred-tank bioreactors on a milliliter-scale facilitate timesaving and cost reducing steady state studies with microorganisms. The applied continuous bioreactor system overcomes the drawbacks of existing miniaturized bioreactors, like poor mass transfer and insufficient process control.

  4. Carbon monoxide mass transfer for syngas fermentation in a stirred tank reactor with dual impeller configurations.

    PubMed

    Ungerman, Andrew J; Heindel, Theodore J

    2007-01-01

    This study compares the power demand and gas-liquid volumetric mass transfer coefficient, kLa, in a stirred tank reactor (STR) (T = 0.211 m) using different impeller designs and schemes in a carbon monoxide-water system, which is applicable to synthesis gas (syngas) fermentation. Eleven different impeller schemes were tested over a range of operating conditions typically associated with the "after large cavity" region (ALC) of a Rushton-type turbine (D/T = 0.35). It is found that the dual Rushton-type impeller scheme exhibits the highest volumetric mass transfer rates for all operating conditions; however, it also displays the lowest mass transfer performance (defined as the volumetric mass transfer coefficient per unit power input) for all conditions due to its high power consumption. Dual impeller schemes with an axial flow impeller as the top impeller show improved mass transfer rates without dramatic increases in power draw. At high gas flow rates, dual impeller schemes with a lower concave impeller have kLa values similar to those of the Rushton-type dual impeller schemes but show improved mass transfer performance. It is believed that the mass transfer performance can be further enhanced for the bottom concave impeller schemes by operating at conditions beyond the ALC region defined for Rushton-type impellers because the concave impeller can handle higher gas flow rates prior to flooding.

  5. [Research on change process of nitrosation granular sludge in continuous stirred-tank reactor].

    PubMed

    Yin, Fang-Fang; Liu, Wen-Ru; Wang, Jian-Fang; Wu, Peng; Shen, Yao-Liang

    2014-11-01

    In order to investigate the effect of different types of reactors on the nitrosation granular sludge, a continuous stirred-tank reactor (CSTR) was studied, using mature nitrosation granular sludge cultivated in sequencing batch reactor (SBR) as seed sludge. Results indicated that the change of reactor type and influent mode could induce part of granules to lose stability with gradual decrease in sludge settling ability during the initial period of operation. However, the flocs in CSTR achieved fast granulation in the following reactor operation. In spite of the changes of particle size distribution, e. g. the decreasing number of granules with diameter larger than 2.5 mm and the increasing number of granules with diameter smaller than 0.3 mm, granular sludge held the absolute predominance of sludge morphology in CSTR during the entire experimental period. Moreover, results showed that the change of reactor type and influent mode didn't affect the nitrite accumulation rate which was still kept at about 85% in effluent. Additionally, the average activity of the sludge in CSTR was stronger than that of the seed sludge, because the newly generated small particles in CSTR had higher specific reactive activity than the larger granules.

  6. Scale-up synthesis of lipase-catalyzed palm esters in stirred-tank reactor.

    PubMed

    Keng, P S; Basri, M; Ariff, A B; Abdul Rahman, M B; Abdul Rahman, R N Z; Salleh, A B

    2008-09-01

    Lipase-catalyzed production of palm esters by alcoholysis of palm oil with oleyl alcohol in n-hexane was performed in 2L stirred-tank reactor (STR). Investigation on the performance of reactor operation was carried out in batch mode STR with single impeller mounted on the centrally located shaft. Rushton turbine (RT) impellers provide the highest reaction yield (95.8%) at lower agitation speed as compared to AL-hydrofoil (AL-H) and 2-bladed elephant ear (EE) impellers. Homogenous enzyme particles suspension was obtained at 250 rpm by using RT impeller. At higher impeller speed, the shear effect on the enzyme particles caused by agitation has decreased the reaction performance. Palm esters reaction mixture in STR follows Newtons' law due to the linear relation between the shear stress (tau) and shear rate (dupsilon/dy). High stability of Lipozyme RM IM was observed as shown by its ability to be repeatedly used to give high percentage yield (79%) of palm esters even after 15 cycles of reaction. The process was successfully scale-up to 75 L STR (50 L working volume) based on a constant impeller tip speed approach, which gave the yield of 97.2% after 5h reaction time.

  7. Dynamics of the microbial community during continuous methane fermentation in continuously stirred tank reactors.

    PubMed

    Tang, Yue-Qin; Shigematsu, Toru; Morimura, Shigeru; Kida, Kenji

    2015-04-01

    Methane fermentation is an attractive technology for the treatment of organic wastes and wastewaters. However, the process is difficult to control, and treatment rates and digestion efficiency require further optimization. Understanding the microbiology mechanisms of methane fermentation is of fundamental importance to improving this process. In this review, we summarize the dynamics of microbial communities in methane fermentation chemostats that are operated using completely stirred tank reactors (CSTRs). Each chemostat was supplied with one substrate as the sole carbon source. The substrates include acetate, propionate, butyrate, long-chain fatty acids, glycerol, protein, glucose, and starch. These carbon sources are general substrates and intermediates of methane fermentation. The factors that affect the structure of the microbial community are discussed. The carbon source, the final product, and the operation conditions appear to be the main factors that affect methane fermentation and determine the structure of the microbial community. Understanding the structure of the microbial community during methane fermentation will guide the design and operation of practical wastewater treatments.

  8. Cassava Stillage Treatment by Thermophilic Anaerobic Continuously Stirred Tank Reactor (CSTR)

    NASA Astrophysics Data System (ADS)

    Luo, Gang; Xie, Li; Zou, Zhonghai; Zhou, Qi

    2010-11-01

    This paper assesses the performance of a thermophilic anaerobic Continuously Stirred Tank Reactor (CSTR) in the treatment of cassava stillage under various organic loading rates (OLRs) without suspended solids (SS) separation. The reactor was seeded with mesophilic anaerobic granular sludge, and the OLR increased by increments to 13.80 kg COD/m3/d (HRT 5d) over 80 days. Total COD removal efficiency remained stable at 90%, with biogas production at 18 L/d (60% methane). Increase in the OLR to 19.30 kg COD/m3/d (HRT 3d), however, led to a decrease in TCOD removal efficiency to 79% due to accumulation of suspended solids and incomplete degradation after shortened retention time. Reactor performance subsequently increased after OLR reduction. Alkalinity, VFA and pH levels were not significantly affected by OLR variation, indicating that no additional alkaline or pH adjustment is required. More than half of the SS in the cassava stillage could be digested in the process when HRT was 5 days, which demonstrated the suitability of anaerobic treatment of cassava stillage without SS separation.

  9. Online measurement of viscosity for biological systems in stirred tank bioreactors.

    PubMed

    Schelden, Maximilian; Lima, William; Doerr, Eric Will; Wunderlich, Martin; Rehmann, Lars; Büchs, Jochen; Regestein, Lars

    2016-11-14

    One of the most critical parameters in chemical and biochemical processes is the viscosity of the medium. Its impact on mixing, as well as on mass and energy transfer is substantial. An increase of viscosity with reaction time can be caused by the formation of biopolymers like xanthan or by filamentous growth of microorganisms. In either case the properties of fermentation broth are changing and frequently non-Newtonian behavior are observed, resulting in major challenges for the measurement and control of mixing and mass transfer. This study demonstrates a method for the online determination of the viscosity inside a stirred tank reactor. The presented method is based on online measurement of heat transfer capacity from the bulk medium to the jacket of the reactor. To prove the feasibility of the method, fermentations with the xanthan producing bacterium Xanthomonas campestris pv. campestris B100 as model system were performed. Excellent correlation between offline measured apparent viscosity and online determined heat transfer capacity were found. The developed tool should be applicable to any other process with formation of biopolymers and filamentous growth. Biotechnol. Bioeng. 2016;9999: 1-8. © 2016 Wiley Periodicals, Inc.

  10. Effect of acidity consumption/production on the pH of aeration tank during the biodegradation of acetic acid/epichlorohydrin.

    PubMed

    Yoon, Seong-Hoon; Kim, Hyung-Soo; Chung, Yun-Chul

    2002-06-01

    In order to elucidate the biologically driven pH fluctuation phenomena in industrial wastewater treatment, the contrary effects of acetic acid (AA) and epichlorohydrin (ECH) on the pH of aeration tank were investigated. Two simple equations were derived to estimate optimum neutralization pHs for the biological AA/ECH wastewater treatment, and the calculated optimum neutralization pHs were compared with experimental results. The pH in aeration tank was expected to fluctuate sharply with the smallest deviation of neutralization pH from the optimum value. However experimental results showed that real pH fluctuation is smaller than the theoretical one. It was considered that carbonate buffer in aqueous system relieves the pH fluctuation. The deviation between experimental and theoretical optimum neutralization pH could be mainly caused by volatility of AA and ECH. The deviation was larger with ECH wastewater of which volatility is larger than AA. Finally, this theory was successfully applied to the real petrochemical wastewater treatment. The pH of aeration tank was properly maintained when acidified wastewater (pH 3.4) was supplied.

  11. Unique differentiation profile of mouse embryonic stem cells in rotary and stirred tank bioreactors.

    PubMed

    Fridley, Krista M; Fernandez, Irina; Li, Mon-Tzu Alice; Kettlewell, Robert B; Roy, Krishnendu

    2010-11-01

    Embryonic stem (ES)-cell-derived lineage-specific stem cells, for example, hematopoietic stem cells, could provide a potentially unlimited source for transplantable cells, especially for cell-based therapies. However, reproducible methods must be developed to maximize and scale-up ES cell differentiation to produce clinically relevant numbers of therapeutic cells. Bioreactor-based dynamic culture conditions are amenable to large-scale cell production, but few studies have evaluated how various bioreactor types and culture parameters influence ES cell differentiation, especially hematopoiesis. Our results indicate that cell seeding density and bioreactor speed significantly affect embryoid body formation and subsequent generation of hematopoietic stem and progenitor cells in both stirred tank (spinner flask) and rotary microgravity (Synthecon™) type bioreactors. In general, high percentages of hematopoietic stem and progenitor cells were generated in both bioreactors, especially at high cell densities. In addition, Synthecon bioreactors produced more sca-1(+) progenitors and spinner flasks generated more c-Kit(+) progenitors, demonstrating their unique differentiation profiles. cDNA microarray analysis of genes involved in pluripotency, germ layer formation, and hematopoietic differentiation showed that on day 7 of differentiation, embryoid bodies from both bioreactors consisted of all three germ layers of embryonic development. However, unique gene expression profiles were observed in the two bioreactors; for example, expression of specific hematopoietic genes were significantly more upregulated in the Synthecon cultures than in spinner flasks. We conclude that bioreactor type and culture parameters can be used to control ES cell differentiation, enhance unique progenitor cell populations, and provide means for large-scale production of transplantable therapeutic cells.

  12. Fully automated single-use stirred-tank bioreactors for parallel microbial cultivations.

    PubMed

    Kusterer, Andreas; Krause, Christian; Kaufmann, Klaus; Arnold, Matthias; Weuster-Botz, Dirk

    2008-04-01

    Single-use stirred tank bioreactors on a 10-mL scale operated in a magnetic-inductive bioreaction block for 48 bioreactors were equipped with individual stirrer-speed tracing, as well as individual DO- and pH-monitoring and control. A Hall-effect sensor system was integrated into the bioreaction block to measure individually the changes in magnetic field density caused by the rotating permanent magnets. A restart of the magnetic inductive drive was initiated automatically each time a Hall-effect sensor indicates one non-rotating gas-inducing stirrer. Individual DO and pH were monitored online by measuring the fluorescence decay time of two chemical sensors immobilized at the bottom of each single-use bioreactor. Parallel DO measurements were shown to be very reliable and independently from the fermentation media applied in this study for the cultivation of Escherichia coli and Saccharomyces cerevisiae. The standard deviation of parallel pH measurements was pH 0.1 at pH 7.0 at the minimum and increased to a standard deviation of pH 0.2 at pH 6.0 or at pH 8.5 with the complex medium applied for fermentations with S. cerevisiae. Parallel pH-control was thus shown to be meaningful with a tolerance band around the pH set-point of +/- pH 0.2 if the set-point is pH 6.0 or lower.

  13. The nonequilibrium electromotive force. I. Measurements in a continuously stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Keizer, Joel; Chang, On-Kok

    1987-10-01

    Based on a statistical thermodynamic theory, it has been predicted [J. Keizer, J. Chem. Phys. 82, 2751 (1985)] that at nonequilibrium steady states the electromotive force (EMF) of an electrochemical cell will differ from the local equilibrium value given by the Nernst equation. We describe here experiments designed to test this prediction for aqueous solutions of Fe2+ and Fe3+ in sulfate buffer. Using a continuously stirred tank reactor driven by a peristaltic pump, a feed solution containing Fe2+ and Fe3+ was mixed with a second feed solution containing the oxidant sodium peroxydisulfate Na2S2O8. The reaction leads to a steady nonequilibrium mixture, which at acidic pH in sulfate buffer is composed of Fe2+ and the ferric sulfate complexes FeSO+4 and Fe(SO4)-2. The EMF of this half-cell was measured vs a saturated calomel reference electrode as a function of residence time in the reactor. These potentials were compared to the Nernst potential calculated on the basis of the concentration ratio of Fe2+ to total Fe3+ at the steady states. The Nernst potential was reproducibly larger than the measured EMF by values that depended on the concentration ratio of Fe2+/Fe3+ in the feed solution and the residence time. The largest deviations were -1.8 mV, which occurred when the Fe2+/Fe3+ ratio was small and the residence time was about 40 s. We have ruled out streaming potentials, junction potentials, and incomplete mixing as the origin of this effect. We show that the dependence of the nonequilibrium portion of the EMF on feed concentrations and residence time is in good agreement with calculations based on methods that are described in the second paper in this series.

  14. Friction Stir Weld Tooling Development for Application on the 2195 Al-Cu-Li Space Transportation System External Tank

    NASA Technical Reports Server (NTRS)

    Loftus, Zachary; Arbegast, W. J.; Hartley, P. J.

    1998-01-01

    Friction Stir Welding (FSW) is a new and innovative solid-state joining process which can be applied to difficult-to- weld aluminum alloys. However, the large forces involved with the process have posed a production tooling challenge. Lockheed Martin Michoud Space Systems has overcome many of these challenges on the Super Lightweight External Tank (ET) program. Utilizing Aluminum-Copper-Lithium alloy 2195 in the form of plate and extrusions, investigations of FSW process parameters have been completed. Major loading mechanisms are discussed in conjunction with deflection measurements. Since the ET program is a cryogenic application, a brief comparison of cryogenic material properties with room temperature material properties is offered for both FSW and fusion welds. Finally, a new approach to controlling the FSW process from a load perspective is introduced. Emphasis will be put on tooling development, as well as the impact of tooling design and philosophy on Friction Stir Weld success probability.

  15. Numerical Simulation of Bubbly Flows in an Aeration Tank with Biochemical Reactions

    NASA Astrophysics Data System (ADS)

    Noor Ul Huda, Khateeb; Shimizu, Kazuya; Gong, Xiaobo; Takagi, Shu

    2016-11-01

    For bubbly flow with biochemical reactions, all the analyses including overall fluid flow, bubble motion, bubble dissolution at local level and bacterial reactions/consumption of substrates are important. The developed system is provided by mixed Eulerian-Lagrangian formulation in which liquid media is represented in Eulerian system and bubbles are tracked individually. Murai and Matsumoto developed a model to track bubbles to predict plume structure in finely dispersed domain. Gong et al. developed the model further to include mass transfer, gas dissolution and mixing phenomenon entrained in this model. In this research we are using the model to include simulation of bacterial biochemical reactions for the purification of water and make it resemble as the wastewater purification tank. The gas bubble dissolution and mass transfer from gas to liquid phase is linked with biochemical reactions for an overall comprehensive study. The main area associated with this research is to incorporate all biochemical reactions in this bubbly flow based on situation of water and demand. In this particular study, various kinds of biomass and substrates are considered. A detailed model for biological wastewater purification involving reactions using bacteria's is developed and primary validation has been carried out based on experimental study. Finally, we tried to achieve physical optimization for this biochemical reactions.

  16. Extended continuous-flow stirred-tank reactor (ECSTR) as a simple model of life under thermodynamically open conditions

    NASA Astrophysics Data System (ADS)

    Takinoue, Masahiro; Ma, Yue; Mori, Yoshihito; Yoshikawa, Kenichi

    2009-07-01

    A continuous-flow stirred-tank reactor (CSTR) is a vital tool for investigating the nonlinear dynamics of chemical systems. This report proposes an extended CSTR (ECSTR) inspired by active and passive transports through a closed membrane in living systems. In addition to the externally-controlled flow in a conventional CSTR, we introduce passive diffusion through a membrane into the ECSTR. This extension allows us to control the chemical dynamics with a larger parameter-dimension. Numerical analyses show that the ECSTR can expand an oscillatory region in the parameter space and can convert a non-oscillatory chemical system to an oscillatory system.

  17. Production of Newcastle Disease Virus by Vero Cells Grown on Cytodex 1 Microcarriers in a 2-Litre Stirred Tank Bioreactor

    PubMed Central

    Arifin, Mohd Azmir; Mel, Maizirwan; Abdul Karim, Mohamed Ismail; Ideris, Aini

    2010-01-01

    The aim of this study is to prepare a model for the production of Newcastle disease virus (NDV) lentogenic F strain using cell culture in bioreactor for live attenuated vaccine preparation. In this study, firstly we investigated the growth of Vero cells in several culture media. The maximum cell number was yielded by culture of Vero cells in Dulbecco's Modified Eagle Medium (DMEM) which was 1.93 × 106 cells/ml. Secondly Vero cells were grown in two-litre stirred tank bioreactor by using several commercial microcarriers. We achieved the maximum cell concentration about 7.95 × 105 cells/ml when using Cytodex 1. Later we produced Newcastle Disease virus in stirred tank bioreactor based on the design developed using Taguchi L4 method. Results reveal that higher multiplicity of infection (MOI) and size of cell inoculums can yield higher virus titer. Finally, virus samples were purified using high-speed centrifugation based on 3∗∗(3-1) Fractional Factorial Design. Statistical analysis showed that the maximum virus titer can be achieved at virus sample concentration of 58.45% (v/v), centrifugation speed of 13729 rpm, and centrifugation time of 4 hours. As a conclusion, high yield of virus titer could be achieved through optimization of cell culture in bioreactor and separation by high-speed centrifugation. PMID:20625497

  18. Establishment of cultivating strategy for highly aggregated mycelia of Morchella esculenta in a stirred-tank bioreactor.

    PubMed

    Ma, Te-Wei; Xiao, Bo-Yuan; Yang, Fan-Chiang

    2012-11-01

    Mycelia of Morchella esculenta were found to aggregate rapidly in a submerged culture, which caused the decrease in dispersed mycelia and the problem of diffusion limitation. The effect of different agitation schemes on the growth of mycelia was investigated in a stirred-tank bioreactor. At the constant speed of 100 or 300 rpm, rapid aggregation caused the biomass concentration to drop to zero in 30 h, which was even worse than achieved under static culture. Intermittent agitation maintained a higher mycelium fragment concentration for 48 h and enhanced the biomass concentration to 4.73 g/L at 120 h. The operation with a polytron connection disrupted effectively mycelium aggregation, thus increasing the specific growth rate, biomass concentration and maximum productivity to 0.0613 1/h, 7.73 g/L and 0.0878 g/L h at 88 h, respectively. Moreover, logistic equations and genetic algorithm (GA) were used for the simulation of biomass growth and estimation of all kinetic coefficients. The operating strategy developed in this study could be used for the production of highly aggregated mycelia, which could also achieve a high cell-density culture in a stirred tank reactor.

  19. Large Spun Formed Friction-Stir Welded Tank Domes for Liquid Propellant Tanks Made from AA2195: A Technology Demonstration for the Next Generation of Heavy Lift Launchers

    NASA Technical Reports Server (NTRS)

    Stachulla, M.; Pernpeinter, R.; Brewster J.; Curreri, P.; Hoffman, E.

    2010-01-01

    Improving structural efficiency while reducing manufacturing costs are key objectives when making future heavy-lift launchers more performing and cost efficient. The main enabling technologies are the application of advanced high performance materials as well as cost effective manufacture processes. This paper presents the status and main results of a joint industrial research & development effort to demonstrate TRL 6 of a novel manufacturing process for large liquid propellant tanks for launcher applications. Using high strength aluminium-lithium alloy combined with the spin forming manufacturing technique, this development aims at thinner wall thickness and weight savings up to 25% as well as a significant reduction in manufacturing effort. In this program, the concave spin forming process is used to manufacture tank domes from a single flat plate. Applied to aluminium alloy, this process allows reaching the highest possible material strength status T8, eliminating numerous welding steps which are typically necessary to assemble tank domes from 3D-curved panels. To minimize raw material costs for large diameter tank domes for launchers, the dome blank has been composed from standard plates welded together prior to spin forming by friction stir welding. After welding, the dome blank is contoured in order to meet the required wall thickness distribution. For achieving a material state of T8, also in the welding seams, the applied spin forming process allows the required cold stretching of the 3D-curved dome, with a subsequent ageing in a furnace. This combined manufacturing process has been demonstrated up to TRL 6 for tank domes with a 5.4 m diameter. In this paper, the manufacturing process as well as test results are presented. Plans are shown how this process could be applied to future heavy-lift launch vehicles developments, also for larger dome diameters.

  20. [Studies on the cell suspension culture of Saussarea medusa in a stirred tank bioreactor].

    PubMed

    Huang, Y; Zhao, D X; Lu, D P; Yan, F; Li, Z H; Chen, H Z; Zhao, Q

    2001-09-01

    The cell suspension culture of Saussarea medusa in a 2L aerated and agitated bioreactor with a four-pitch-blade impeller was investigated. The effects of agitation speed, aeration and inoculum size on cell growth and flavonoids production were studied and it was found that cells had optimum growth and flavonoids production when cultivated at 75 r/min, 700-1000 L/min and an inoculum of 4.0-5.0 g/L. A high cell biomass of 13.8 g/L and flavonoids production of 416 mg/L were achieved after 12 days of cultivation. Time course study revealed that flavonoids biosynthesis was growth-associated. The studies on aggregates size distribution in the bioreactor showed that the aggregates break-up caused by hydrodynamic stress might adversely affect cell growth and lead to significant reduction of cell biomass and flavonoids production.

  1. Nondestructive Inspection Techniques for Friction Stir Weld Verification on the Space Shuttle External Tank

    NASA Technical Reports Server (NTRS)

    Suits, Michael W.; Leak, Jeffery; Bryson, Craig

    2003-01-01

    Friction Stir Welding (FSW) has gained wide acceptance as a reliable joining process for aerospace hardware as witnessed by its recent incorporation into the Delta Launch vehicle cryotanks. This paper describes the development of nondestructive evaluation methods and techniques used to verify the FSW process for NASA's Space Shuttle.

  2. Production of polygalacturonases by Aspergillus oryzae in stirred tank and internal- and external-loop airlift reactors.

    PubMed

    Fontana, Roselei Claudete; da Silveira, Maurício Moura

    2012-11-01

    The production of endo- and exo-polygalacturonase (PG) by Aspergillus oryzae was assessed in stirred tank reactors (STRs), internal-loop airlift reactors (ILARs) and external-loop airlift reactors (ELARs). For STR production, we compared culture media formulated with either pectin (WBE) or partially hydrolyzed pectin. The highest enzyme activities were obtained in medium that contained 50% pectin in hydrolyzed form (WBE5). PG production in the three reactor types was compared for WBE5 and low salt WBE medium, with additional salts added at 48, 60 and 72h (WBES). The ELARs performed better than the ILARs in WBES medium where the exo-PG was the same concentration as for STRs and the endo-PG was 20% lower. These results indicate that PG production is higher under experimental conditions that result in higher cell growth with minimum pH values less than 3.0.

  3. CFD simulation of the laminar flow in stirred tanks generated by double helical ribbons and double helical screw ribbons impellers

    NASA Astrophysics Data System (ADS)

    Driss, Zied; Karray, Sarhan; Kchaou, Hedi; Abid, Mohamed Salah

    2011-12-01

    In this paper, the mixing performance of double helical ribbons and double helical screw ribbons impellers mounted on stirred tanks is numerical investigated. The computer simulations are conducted within a specific computational fluid dynamic (CFD) code, based on resolution of the Naviers-Stokes equations in the laminar flow with a finite volume discretization. The field velocity and the viscous dissipation rate are presented in different vessel planes. The global characteristics and the power consumption of these impellers are also studied. The numerical results showed that the velocity field is more active with the double helical screw ribbons impeller. In this case, the effectiveness of the viscous dissipation and the pumping flow has been obviously noted. Also, the pumping and the energy efficiency reach the highest values at the same Reynolds number. The good agreement between the numerical results and the experimental data quietly confirmed the analysed method.

  4. Stochastic resonance in the presence or absence of external signal in the continuous stirred tank reactor system

    NASA Astrophysics Data System (ADS)

    Hou, Zhonghuai; Xin, Houwen

    1999-07-01

    A two variable model, which has been proposed to describe a first-order, exothermic, irreversible reaction A→B carried out in a continuous stirred tank reactor (CSTR), is investigated when the control parameter is modulated by random and/or periodic forces. Within the bistable region where a limit cycle and a stable node coexist, stochastic resonance (SR) is observed when both random and periodic modulations are present. In the absence of periodic external signal noise induced coherent oscillations (NICO) appear when the control parameter is randomly modulated near the supercritical Hopf bifurcation point. In addition, the NICO-strength goes through a maximum with the increment of the noise intensity, characteristic for the occurrence of internal signal stochastic resonance (ISSR).

  5. Comparison between continuous stirred tank reactor extractor and soxhlet extractor for extraction of El-Lajjun oil shale

    SciTech Connect

    Anabtawi, M.Z.

    1996-02-01

    Extraction on El-Lajjun oil shale in a continuous stirred tank reactor extractor (CSTRE) and a Soxhlet extractor was carried out using toluene and chloroform as solvents. Solvents were recovered using two distillation stages, a simple distillation followed by a fractional distillation. Gas chromotography was used to test for the existence of trapped solvent in the yield. It was found that extraction using a CSTRE gave a 12% increase in yield on average compared with the Soxhlet extractor, and an optimum shale size of 1.0mm offered a better yield and solvent recovery for both techniques. It was also found that an optimum ratio of solvent to oil shale of 2:1 gave the best oil yield. The Soxhlet extractor was found to offer an extraction rate of 1 hour to complete extraction compared with 4 hours in a CSTRE. The yield in a CSTRE was found to increase on increase of stirring. When extraction was carried out at the boiling point of the solvents in a CSTRE, the yield was found to increase by 30% on average compared to that of extraction when the solvent was at room temperature. When toluene was used for extraction, the average amount of bitumen extracted was 0.032 g/g of oil shale and 76.4% of the solvent recovered, compared with 0.037 g/g of oil shale and 84.1% of the solvent recovered using a Soxhlet extractor.

  6. Gaseous hexane biodegradation by Fusarium solani in two liquid phase packed-bed and stirred-tank bioreactors.

    PubMed

    Arriaga, Sonia; Muñoz, Raúl; Hernández, Sergio; Guieysse, Benoit; Revah, Sergio

    2006-04-01

    Biofiltration of hydrophobic volatile pollutants is intrinsically limited by poor transfer of the pollutants from the gaseous to the liquid biotic phase, where biodegradation occurs. This study was conducted to evaluate the potential of silicone oil for enhancing the transport and subsequent biodegradation of hexane by the fungus Fusarium solani in various bioreactor configurations. Silicone oil was first selected among various solvents for its biocompatibility, nonbiodegradability, and good partitioning properties toward hexane. In batch tests, the use of silicone oil improved hexane specific biodegradation by approximately 60%. Subsequent biodegradation experiments were conducted in stirred-tank (1.5 L) and packed-bed (2.5 L) bioreactors fed with a constant gaseous hexane load of 180 g x m(-3)(reactor) x h(-1) and operated for 12 and 40 days, respectively. In the stirred reactors, the maximum hexane elimination capacity (EC) increased from 50 g x m(-3)(reactor) x h(-1) (removal efficiency, RE of 28%) in the control not supplied with silicone oil to 120 g x m(-3)(reactor) x h(-1) in the biphasic system (67% RE). In the packed-bed bioreactors, the maximum EC ranged from 110 (50% RE) to 180 g x m(-3)(reactor) x h(-1) (> 90% RE) in the control and two-liquid-phase systems, respectively. These results represent, to the best of our knowledge, the first reported case of fungi use in a two-liquid-phase bioreactor and the highest hexane removal capacities so far reported in biofilters.

  7. Monitoring the aeration efficiency and carbon footprint of a medium-sized WWTP: experimental results on oxidation tank and aerobic digester.

    PubMed

    Caivano, Marianna; Bellandi, Giacomo; Mancini, Ignazio M; Masi, Salvatore; Brienza, Rosanna; Panariello, Simona; Gori, Riccardo; Caniani, Donatella

    2017-03-01

    The efficiency of aeration systems should be monitored to guarantee suitable biological processes. Among the available tools for evaluating the aeration efficiency, the off-gas method is one of the most useful. Increasing interest towards reducing greenhouse gas (GHG) emissions from biological processes has resulted in researchers using this method to quantify N2O and CO2 concentrations in the off-gas. Experimental measurements of direct GHG emissions from aerobic digesters (AeDs) are not available in literature yet. In this study, the floating hood technique was used for the first time to monitor AeDs. The floating hood technique was used to evaluate oxygen transfer rates in an activated sludge (AS) tank of a medium-sized municipal wastewater treatment plant located in Italy. Very low values of oxygen transfer efficiency were found, confirming that small-to-medium-sized plants are often scarcely monitored and wrongly managed. Average CO2 and N2O emissions from the AS tank were 0.14 kgCO2/kgbCOD and 0.007 kgCO2,eq/kgbCOD, respectively. For an AeD, 3 × 10(-10) kgCO2/kgbCOD direct CO2 emissions were measured, while CO2,eq emissions from N2O were 4 × 10(-9) kgCO2,eq/kgbCOD. The results for the AS tank and the AeD were used to estimate the net carbon and energy footprint of the entire plant.

  8. Protozoan Fauna and Abundance in Aeration Tanks of Three Municipal Wastewater Treatment Plants in the Eastern Cape Province of South Africa

    NASA Astrophysics Data System (ADS)

    Sibewu, M.; Momba, M. N. B.; Okoh, A. L.

    This study focuses on the assessment of the protozoan fauna and abundance in the mixed liquors of aeration tanks of the three municipal wastewater treatment plants located in Fort Beaufort, Dimbaza and East London in the Eastern Cape Province of South Africa and their implication to the production of effluents of good quality. The samples were collected between September and December 2005 and protozoa species were identified by direct microscopic observations at x400 magnification by comparison with existing protozoa gallery collections. A total of 68 protozoan genera made up of 44 ciliates, 16 flagellates and 8 others were identified in wastewater treatment plants. Although in all aerobic zones the average density of ciliates was 104 cells mL-1, which indicated that these plants were able to produce clear effluent of good quality, a better performance was found in Dimbaza and East London, which had total protozoan genera of 27 and 26, respectively.

  9. Numerical simulation on macro-instability of coupling flow field structure in jet-stirred tank

    NASA Astrophysics Data System (ADS)

    Luan, D. Y.; Lu, J. P.; Bu, Q. X.; Zhang, S. F.; Zheng, S. X.

    2016-05-01

    The velocity field macro-instability (MI) can help to improve the mixing efficiency. In this work, the MI features of flow field induced by jet-stirred coupling action is studied by using computational fluid dynamics (CFD) simulations. The numerical simulation method of jet-stirred model was established based on standard turbulent equations, and the impeller rotation was modeled by means of the Sliding Mesh (SM) technology. The numerical results of test fluid (water) power consumption were compared with the data obtained by power test experiments. The effects of jet flow velocity and impeller speed on MI frequency were analyzed thoroughly. The results show that the calculated values of power consumption agree well with the experiment measured data, which validates the turbulent model, and the flow structure and MI frequency distribution are affected by both impeller speed and jet flow rate. The amplitude of MI frequency increases obviously with the increasing rotation speed of impeller and the eccentric jet rate, and it can be enhanced observably by eccentric jet rate, in condition of comparatively high impeller speed. At this time, the MI phenomenon disappears with the overall chaotic mixing.

  10. Development of Inspection for Friction Stir Welds for Rocket Fuel Tanks

    NASA Technical Reports Server (NTRS)

    Russell, Samuel S.

    2012-01-01

    During development of the Ares I weld processes nondestructive and destructive testing were used to identify and characterize defects that occurred. These defects were named and character noted. This catalogue of defects and characteristics was then used to develop inspection methods for Self Reacting Friction Stir Welds (SR ]FSW) and Conventional Friction Stir Welds (C ]FSW). Dye penetrant, eddy current, x ]radiography, single element ultrasonic, and phased array ultrasonic (PAUT) inspection procedures were developed to target the expected defects. Once the method procedure was developed a comparison was performed to allow for selection of the best inspection method. Tests of the effectiveness of the inspection were performed on purposely fabricated flawed specimens and electrodischarge machined notches. The initial test results prompted a revisit of the PAUT procedure and a redesign of the inspection. Subsequent testing showed that a multi ]angle PAUT inspection resulted in better detection capability. A discussion of the most effective orientations of the PAUT transducer will be presented. Also, the implementation of the inspection on production hardware will be presented. In some cases the weld tool is used as the transducer manipulator and in some cases a portable scanner is used

  11. Modeling of gas-liquid mass transfer in a stirred tank bioreactor agitated by a Rushton turbine or a new pitched blade impeller.

    PubMed

    Gelves, Ricardo; Dietrich, A; Takors, Ralf

    2014-03-01

    A combined computational fluid dynamics (CFD) and population balance model (PBM) approach has been applied to simulate hydrodynamics and mass transfer in a 0.18 m(3) gas-liquid stirred bioreactor agitated by (1) a Rushton turbine, and (2) a new pitched blade geometry with rotating cartridges. The operating conditions chosen were motivated by typical settings used for culturing mammalian cells. The effects of turbulence, rotating flow, bubbles breakage and coalescence were simulated using the k-ε, multiple reference frame (MRF), Sliding mesh (SM) and PBM approaches, respectively. Considering the new pitched blade geometry with rotating aeration microspargers, [Formula: see text] mass transfer was estimated to be 34 times higher than the conventional Rushton turbine set-up. Notably, the impeller power consumption was modeled to be about 50 % lower. Independent [Formula: see text] measurements applying the same operational conditions confirmed this finding. Motivated by these simulated and experimental results, the new aeration and stirring device is qualified as a very promising tool especially useful for cell culture applications which are characterized by the challenging problem of achieving relatively high mass transfer conditions while inserting only low stirrer energy.

  12. Scale-up of biotransformation process in stirred tank reactor using dual impeller bioreactor.

    PubMed

    Shukla, V B.; Parasu Veera, U; Kulkarni, P R.; Pandit, A B.

    2001-07-01

    The gas-liquid mass transfer coefficient K(L)a in the fermenter is a strong function of mode of energy dissipation and physico-chemical properties of the liquid media. A combination of disc turbine (DT) and pitched blade turbine down flow (PTD) impellers has been tested in laboratory bioreactor for gas hold-up and gas-liquid mass transfer performance for the growth and biotransformation medium for an yeast isolate VS1 capable of biotransforming benzaldehyde to L-phenyl acetyl carbinol (L-PAC) and compared with those in water.Correlations have been developed for the prediction of the fractional gas hold-up and gas-liquid mass transfer coefficient for the above media. The mass transfer coefficient and respiration rate have been determined in the shake flask for the growth as well as for biotransformation medium. These results, then have been used to optimize the operating parameters (impeller speed and aeration) for growth and biotransformation in a laboratory bioreactor. The comparison of cell mass production and L-PAC production in the bioreactor has been done with that obtained in shake flask studies.

  13. Bio-processing of copper from combined smelter dust and flotation concentrate: a comparative study on the stirred tank and airlift reactors.

    PubMed

    Vakylabad, Ali Behrad; Schaffie, Mahin; Ranjbar, Mohammad; Manafi, Zahra; Darezereshki, Esmaeel

    2012-11-30

    To scrutinize the influence of the design and type of the bioreactors on the bioleaching efficiency, the bioleaching were evaluated in a batch airlift and a batch stirred tank bioreactors with mixed mesophilic and mixed moderately thermophilic bacteria. According to the results, maximum copper recoveries were achieved using the cultures in the stirred tank bioreactors. It is worth noting that the main phase of the flotation concentrate was chalcopyrite (as a primary sulphide), but the smelter dust mainly contained secondary copper sulphides such as Cu(2)S, CuS, and Cu(5)FeS(4).Under optimum conditions, copper dissolution from the combined flotation concentrate and smelter dust (as an environmental hazard) reached 94.50% in the STR, and 88.02% in the airlift reactor with moderately thermophilic, after 23 days. Also, copper extractions calculated for the bioleaching using mesophilic bacteria were 48.73% and 37.19% in the STR (stirred tank reactor) and the airlift bioreactor, respectively. In addition, the SEM/EDS, XRD, chemical, and mineralogical analyses and studies confirmed the above results.

  14. Efficient azo dye decolorization in a continuous stirred tank reactor (CSTR) with built-in bioelectrochemical system.

    PubMed

    Cui, Min-Hua; Cui, Dan; Gao, Lei; Cheng, Hao-Yi; Wang, Ai-Jie

    2016-10-01

    A continuous stirred tank reactor with built-in bioelectrochemical system (CSTR-BES) was developed for azo dye Alizarin Yellow R (AYR) containing wastewater treatment. The decolorization efficiency (DE) of the CSTR-BES was 97.04±0.06% for 7h with sludge concentration of 3000mg/L and initial AYR concentration of 100mg/L, which was superior to that of the sole CSTR mode (open circuit: 54.87±4.34%) and the sole BES mode (without sludge addition: 91.37±0.44%). The effects of sludge concentration and sodium acetate (NaAc) concentration on azo dye decolorization were investigated. The highest DE of CSTR-BES for 4h was 87.66±2.93% with sludge concentration of 12,000mg/L, NaAc concentration of 2000mg/L and initial AYR concentration of 100mg/L. The results in this study indicated that CSTR-BES could be a practical strategy for upgrading conventional anaerobic facilities against refractory wastewater treatment.

  15. Continuous stirred-tank-reactor investigation of the gas-phase reaction of hydroxyl radicals and toluene

    SciTech Connect

    Gery, M.W.; Fox, D.L.; Jeffries, H.E.; Stockburger, L.; Weathers, W.S.

    1985-01-01

    A continuous stirred-tank reactor (CSTR) was used to study the gas-phase reaction between HO and toluene. HO was generated by the in situ photolysis of nitrous acid. Flow-reactor operation at steady-state conditions with a residence time of 20 minutes allowed investigation of primary and very rapid secondary reactions. CSTR and batch-reactor experiments were also performed with selected products. Both gas-phase and aerosol products were identified by chromatography and mass spectroscopy, with total product yields between 55 and 75% of reacted carbon. Toluene reaction products included cresols, nitrocresols, nitrotoluenes, 3,5-dinitrotoluene, benzaldehyde, benzyl nitrate, nitrophenols, methyl-p-benzoquinone, methylglyoxal, glyoxal, formaldehyde, methyl nitrate, PAN, and CO. The fraction of HO methyl hydrogen abstraction was calculated to be 0.13 + or - 0.04. The ratio of reaction rate constants for nitrotoluene versus cresol formation from the HO adduct was calculated to be about 3.3 x 10,000. Also, the ratio of cresol formation versus O2 addition to the HO adduct was estimated to be > or = 0.55. Comparisons of these measurements with previous values and the implications with respect to photochemical kinetics modeling of the atmosphere are discussed.

  16. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor.

    PubMed

    Jitrwung, Rujira; Yargeau, Viviane

    2015-05-11

    Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR). Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol) and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol.

  17. Biohydrogen and Bioethanol Production from Biodiesel-Based Glycerol by Enterobacter aerogenes in a Continuous Stir Tank Reactor

    PubMed Central

    Jitrwung, Rujira; Yargeau, Viviane

    2015-01-01

    Crude glycerol from the biodiesel manufacturing process is being produced in increasing quantities due to the expanding number of biodiesel plants. It has been previously shown that, in batch mode, semi-anaerobic fermentation of crude glycerol by Enterobacter aerogenes can produce biohydrogen and bioethanol simultaneously. The present study demonstrated the possible scaling-up of this process from small batches performed in small bottles to a 3.6-L continuous stir tank reactor (CSTR). Fresh feed rate, liquid recycling, pH, mixing speed, glycerol concentration, and waste recycling were optimized for biohydrogen and bioethanol production. Results confirmed that E. aerogenes uses small amounts of oxygen under semi-anaerobic conditions for growth before using oxygen from decomposable salts, mainly NH4NO3, under anaerobic condition to produce hydrogen and ethanol. The optimal conditions were determined to be 500 rpm, pH 6.4, 18.5 g/L crude glycerol (15 g/L glycerol) and 33% liquid recycling for a fresh feed rate of 0.44 mL/min. Using these optimized conditions, the process ran at a lower media cost than previous studies, was stable after 7 days without further inoculation and resulted in yields of 0.86 mol H2/mol glycerol and 0.75 mol ethanol/mole glycerol. PMID:25970750

  18. Application of a continuously stirred tank bioreactor (CSTR) for bioremediation of hydrocarbon-rich industrial wastewater effluents.

    PubMed

    Gargouri, Boutheina; Karray, Fatma; Mhiri, Najla; Aloui, Fathi; Sayadi, Sami

    2011-05-15

    A continuously stirred tank bioreactor (CSTR) was used to optimize feasible and reliable bioprocess system in order to treat hydrocarbon-rich industrial wastewaters. A successful bioremediation was developed by an efficient acclimatized microbial consortium. After an experimental period of 225 days, the process was shown to be highly efficient in decontaminating the wastewater. The performance of the bioaugmented reactor was demonstrated by the reduction of COD rates up to 95%. The residual total petroleum hydrocarbon (TPH) decreased from 320 mg TPH l(-1) to 8 mg TPH l(-1). Analysis using gas chromatography-mass spectrometry (GC-MS) identified 26 hydrocarbons. The use of the mixed cultures demonstrated high degradation performance for hydrocarbons range n-alkanes (C10-C35). Six microbial isolates from the CSTR were characterized and species identification was confirmed by sequencing the 16S rRNA genes. The partial 16S rRNA gene sequences demonstrated that 5 strains were closely related to Aeromonas punctata (Aeromonas caviae), Bacillus cereus, Ochrobactrum intermedium, Stenotrophomonas maltophilia and Rhodococcus sp. The 6th isolate was affiliated to genera Achromobacter. Besides, the treated wastewater could be considered as non toxic according to the phytotoxicity test since the germination index of Lepidium sativum ranged between 57 and 95%. The treatment provided satisfactory results and presents a feasible technology for the treatment of hydrocarbon-rich wastewater from petrochemical industries and petroleum refineries.

  19. Citrus peel influences the production of an extracellular naringinase by Staphylococcus xylosus MAK2 in a stirred tank reactor.

    PubMed

    Puri, Munish; Kaur, Aneet; Barrow, Colin J; Singh, Ram Sarup

    2011-02-01

    Staphylococcus xylosus MAK2, Gram-positive coccus, a nonpathogenic member of the coagulase-negative Staphylococcus family was isolated from soil and used to produce naringinase in a stirred tank reactor. An initial medium at pH 5.5 and a cultivation temperature of 30°C was found to be optimal for enzyme production. The addition of Ca(+)² caused stimulation of enzyme activity. The effect of various physico-chemical parameters, such as pH, temperature, agitation, and inducer concentration was studied. The enzyme production was enhanced by the addition of citrus peel powder (CPP) in the optimized medium. A twofold increase in naringinase production was achieved using different technological combinations. The process optimization using technological combinations allowed rapid optimization of large number of variables, which significantly improved enzyme production in a 5-l reactor in 34 h. An increase in sugar concentration (15 g l⁻¹) in the fermentation medium further increased naringinase production (8.9 IU ml⁻¹) in the bioreactor. Thus, availability of naringinase renders it attractive for potential biotechnological applications in citrus processing industry.

  20. Production of biohythane from food waste via an integrated system of continuously stirred tank and anaerobic fixed bed reactors.

    PubMed

    Yeshanew, Martha M; Frunzo, Luigi; Pirozzi, Francesco; Lens, Piet N L; Esposito, Giovanni

    2016-11-01

    The continuous production of biohythane (mixture of biohydrogen and methane) from food waste using an integrated system of a continuously stirred tank reactor (CSTR) and anaerobic fixed bed reactor (AFBR) was carried out in this study. The system performance was evaluated for an operation period of 200days, by stepwise shortening the hydraulic retention time (HRT). An increasing trend of biohydrogen in the CSTR and methane production rate in the AFBR was observed regardless of the HRT shortening. The highest biohydrogen yield in the CSTR and methane yield in the AFBR were 115.2 (±5.3)L H2/kgVSadded and 334.7 (±18.6)L CH4/kgCODadded, respectively. The AFBR presented a stable operation and excellent performance, indicated by the increased methane production rate at each shortened HRT. Besides, recirculation of the AFBR effluent to the CSTR was effective in providing alkalinity, maintaining the pH in optimal ranges (5.0-5.3) for the hydrogen producing bacteria.

  1. Reuse of drinking water treatment residuals in a continuous stirred tank reactor for phosphate removal from urban wastewater.

    PubMed

    Bai, Leilei; Wang, Changhui; Pei, Yuansheng; Zhao, Jinbo

    2014-01-01

    This work proposed a new approach of reusing drinking water treatment residuals (WTR) in a continuous stirred tank reactor (CSTR) to remove phosphate (P) from urban wastewater. The results revealed that the P removal efficiency of the WTR was more than 94% for urban wastewater, in the condition of initial P concentration (P0) of 10 mg L⁻¹, hydraulic retention time (HRT) of 2 h and WTR dosage (M0) of 10 g L⁻¹. The P mass transfer from the bulk to the solid-liquid interface in the CSTR system increased at lower P0, higher M0 and longer HRT. The P adsorption capacity of WTR from urban wastewater was comparable to that of the 201 × 4 resin and unaffected by ions competition. Moreover, WTR had a limited effect on the metals' (Fe, Al, Zn, Cu, Mn and Ni) concentrations of the urban wastewater. Based on the principle of waste recycling, the reuse of WTR in CSTR is a promising alternative technology for P removal from urban wastewater.

  2. Enhanced production of artemisinin by hairy root cultivation of Artemisia annua in a modified stirred tank reactor.

    PubMed

    Patra, Nivedita; Srivastava, Ashok K

    2014-11-01

    Artemisinin is an important drug commonly used in the treatment of malaria as a combination therapy. It is primarily produced by a plant Artemisia annua, however, its supply from plant is significantly lower than its huge demand and therefore alternative in vitro production routes are sought. Hairy root cultivation could be one such alternative production protocol. Agrobacterium rhizogenes was used to induce hairy roots of A. annua. Statistical optimization of media was thereafter attempted to maximize the biomass/artemisinin production. The growth and product formation kinetics and the significant role of O2 in hairy root propagation were established in optimized media. Mass cultivation of hairy roots was, thereafter, attempted in a modified 3-L Stirred Tank Bioreactor (Applikon Dependable Instruments, The Netherlands) using optimized culture conditions. The reactor was suitably modified to obtain profuse growth of hairy roots by segregating and protecting the growing roots from the agitator rotation in the reactor using a perforated Teflon disk. It was possible to produce 18 g biomass L(-1) (on dry weight basis) and 4.63 mg L(-1) of artemisinin in 28 days, which increased to 10.33 mg L(-1) by the addition of elicitor methyl jasmonate.

  3. Entropy production in a chemical system involving an autocatalytic reaction in an isothermal, continuous stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Yoshida, Nobuo

    1990-02-01

    The rate of entropy production due to chemical reaction is calculated for various combinations of parameter values in the cubic autocatalator model in an isothermal, continuous stirred tank reactor (CSTR) proposed by Gray and Scott and by Escher and Ross. Values of the entropy production averaged over periods of limit cycle oscillations are compared with those in coexistent unstable stationary states. It is found that in ranges of the residence time over which there are limit cycles, the entropy production in coexisting stationary states increases as the residence time is shortened, i.e., as the system is removed farther from thermodynamic equilibrium. The average entropy production over a limit cycle is less than that in the corresponding stationary state over wide ranges of parameter values, but not necessarily for the whole oscillatory region. More specifically, the former inequality always prevails in ranges where the entropy production of stationary states is larger, i.e., the residence time is shorter, but in some cases the inequality is reversed in ranges of lower magnitudes of the entropy production.

  4. Serial completely stirred tank reactors for improving biogas production and substance degradation during anaerobic digestion of corn stover.

    PubMed

    Li, YuQian; Liu, ChunMei; Wachemo, Akiber Chufo; Yuan, HaiRong; Zou, DeXun; Liu, YanPing; Li, XiuJin

    2017-03-11

    Several completely stirred tank reactors (CSTR) connected in series for anaerobic digestion of corn stover were investigated in laboratory scale. Serial anaerobic digestion systems operated at a total HRT of 40days, and distribution of HRT are 10+30days (HRT10+30d), 20+20days (HRT20+20d), and 30+10days (HRT30+10d) were compared to a conventional one-step CSTR at the same HRT of 40d. The results showed that in HRT10+30d serial system, the process became very unstable at organic load of 50gTS·L(-1). The HRT20+20d and HRT30+10d serial systems improved methane production by 8.3-14.6% compared to the one-step system in all loads of 50, 70, 90gTS·L(-1). The conversion rates of total solid, cellulose, and hemicellulose were increased in serial anaerobic digestion systems compared to single system. The serial systems showed more stable process performance in high organic load. HRT30+10d system showed the best biogas production and conversions among all systems.

  5. Quantifying the Reactive Uptake of OH by Organic Aerosols in aContinuous Flow Stirred Tank Reactor

    SciTech Connect

    Che, Dung L.; Smith, Jared D.; Leone, Stephen R.; Ahmed, Musahid; Wilson, Kevin R.

    2009-03-01

    Here we report a new method for measuring the heterogeneous chemistry of submicron organic aerosol particles using a continuous flow stirred tank reactor. This approach is designed to quantify the real time heterogeneous kinetics, using a relative rate method, under conditions of low oxidant concentration and long reaction times that more closely mimic the real atmosphere. A general analytical expression, which couples the aerosol chemistry with the flow dynamics in the chamber is developed and applied to the heterogeneous oxidation of squalane particles by hydroxyl radicals (OH) in the presence of O2. The particle phase reaction is monitored via photoionization aerosol mass spectrometry and yields a reactive uptake coefficient of 0.51+-0.10, using OH concentrations of 1-7x108 molec cdot cm-3 and reaction times of 1.5+-3 hours. This uptake coefficient is larger than that found for the reaction carried out under high OH concentrations (~;;1x1010 molec cdot cm-3) and short reaction times in a flow tube reactor. This difference suggests that oxidant concentration and reaction time are not interchangeable quantities in reactions of organic aerosols with radicals. In general, this approach provides a new way to examine how the chemical aging of organic particles measured at short reaction times and high oxidant concentrations in flow tubes might differ from the long reaction times and low oxidant levels found in the real atmosphere.

  6. Batch and Pulsed Fed-Batch Cultures of Aspergillus flavipes FP-500 Growing on Lemon Peel at Stirred Tank Reactor.

    PubMed

    Wolf-Márquez, V E; García-García, E; García-Rivero, M; Aguilar-Osorio, G; Martínez Trujillo, M A

    2015-11-01

    Aspergillus flavipes FP-500 grew up on submerged cultures using lemon peel as the only carbon source, developing several batch and pulsed fed-batch trials on a stirred tank reactor. The effect of carbon source concentration, reducing sugar presence and initial pH on exopectinase and endopectinase production, was analyzed on batch cultures. From this, we observed that the highest substrate concentration favored biomass (X max) but had not influence on the corresponding specific production (q p) of both pectinases; the most acid condition provoked higher endopectinase-specific productions but had not a significant effect on those corresponding to exopectinases; and reducing sugar concentrations higher than 1.5 g/L retarded pectinase production. On the other hand, by employing the pulsed fed-batch operation mode, we observed a prolonged growth phase, and an increase of about twofold on endopectinase production without a significant raise on biomass concentration. So, pulsed fed-batch seems to be a good alternative for obtaining higher endopectinase titers by using high lemon peel quantities without having mixing and repression problems to the system. The usefulness of unstructured kinetic models for explaining, under a theoretic level, the behavior of the fungus along the batch culture with regard to pectinase production was evident.

  7. Design of high efficiency and energy saving aeration device for aquaculture

    NASA Astrophysics Data System (ADS)

    Liu, Sibo

    2017-03-01

    Energy efficient aeration device for aquaculture, in line with "by more than a generation, dynamic aeration" train of thought for technical design and improvement. Removable aeration terminal as the core, multi-level water to improve the method, the mobile fading pore aeration, intelligent mobile and open and close as the main function, aimed at solving the existing pond aeration efficiency, low energy consumption is high, the function of a single problem. From energy saving, efficiency, biological bacteria on the three directions, the aquaculture industry of energy conservation and emissions reduction. Device of the main advantages are: 1, original mobile fading aerator on the one hand, to expand the scope of work, playing a micro porous aeration of dissolved oxygen with high efficiency and to achieve "by more than a generation", on the other hand, through the sports equipment, stir the mixture of water, the water surface of photosynthesis of plants rich in dissolved oxygen input parts of the tank, compared to the stillness of the aerator can be more fully dissolved oxygen.2, through the opening of the pressure sensor indirect control device, can make the equipment timely and stop operation, convenient in use at the same time avoid the waste of energy.3, the biofilm suspension in aeration terminal, can be accomplished by nitration of microbial multi-level water improvement, still can make biofilm increase rate of netting in the movement process, the biological and mechanical aerobic promote each other, improve the efficiency of both. In addition, the device has small power consumption, low cost of characteristics. And have a certain degree of technical barriers, have their own intellectual property rights, and high degree of product market demand, easily accepted by customers, has a very high popularization value.

  8. Kinetics of batch single cell protein production from rice polishings with Candida utilis in continuously aerated tank reactors.

    PubMed

    Rajoka, M Ibrahim; Khan, Sohail Hassan; Jabbar, M A; Awan, M S; Hashmi, A S

    2006-10-01

    Single cell protein was produced from the defatted rice polishings by fermentation with Candida utilis in an aerated 14-L fermentor to optimize bioprocess variables. Maximum values of specific growth rate coefficient (mu, h(-1)), cell mass yield (Y(X/S), g/g) and cell mass productivity (g/Lh) were 0.31, 0.65, and 1.24, respectively under optimized conditions of aeration rate (1 v.v(-1) m(-1)), dissolved oxygen (50%), corn steep liquor (5%), temperature (35 degrees C), and substrate concentration (90 g rice polishings/L) in yeast salt medium (pH 6.0). The kinetic parameters for 50-L fermentor under same conditions were 0.33 h(-1), 0.66 g/g, 1.33 g/Lh, 2.25 g/Lh, 1.23 g/Lh, 0.45 g/g substrate and 0.20 g/g cell h for mu, Y(X/S), Q(X), Q(S), Q(CP), Y(TP/S), and q(CP), respectively and were significantly higher than their respective values reported on C. utilis in batch culture studies. This biomass protein contained 23.6%, 32.75%, 11.50%, 12.95%, 10.5%, and 0.275% true protein, crude protein, crude fiber, ash, cellulose and RNA content respectively. This implied that the fermentation process could be up scaled to manufacture animal feed. Gross metabolizable energy content of dried SCP was 29,711 kcal/kg and indicated that the SCP could serve both as energy as well as a protein source. Yeast can replace expensive feed ingredients currently being incorporated in poultry feed and can reduce cost of poultry ration by 0.33 US dollars-0.51 US dollars/100 kg bag and improve the economics of feed production in our country.

  9. Biodegradation of perchlorate from real and synthetic effluent by Proteobacterium ARJR SMBS in a stirred tank bioreactor system.

    PubMed

    Raj, J R Anoop; Muruganandam, L

    2013-01-01

    The present work is a laboratory-scale study of perchlorate degradation using Proteobacterium ARJR SMBS in a stirred tank bioreactor (STBR). Anaerobically grown cultures of ARJR SMBS exposed to a variety of ClO4(-) levels within the range 30 to 150 mg L(-1) under anoxic conditions have been studied. The chloride released was measured and the average value found to be 43.55 mg L(-1). The average daily value of perchlorate degradation rate in this system was 17.24 mg L(-1) at optimum pH 7.5 and 0.25% NaCl salinity. The mixed liquor suspension solids of the system gradually increased from 0.025-0.156 g L(-1) during the operating period of 55 days. Mass balance indicated that the chloride produced was 0.45 mole per mole of perchlorate. The salinity of the system varied from 2.50-18.46 g L(-1), dependent primarily upon the inlet perchlorate concentration. The degradation mechanism, which obeyed a first-order substrate-utilizing kinetic model, allowed the growth rates and the half-saturation constants to be determined. The maximum observed anoxic growth rates (0.83-1.2 h(-1)) for ARJR SMBS in a synthetic effluent (SE) were considerably higher than in real effluent (RE) (0.45-0.59 h(-1)). The biomass yield of ARJR SMBS in STBR was higher in SE (1 +/- 0.4 mg L(-1)) than in RE (1 +/- 0.1 mg L(-1)). From the experimental findings, the uptake of perchlorate by the bacterium is suggested to be a non-interfacially-based mechanism. Under steady state operating condition the performance of the reactor was comparatively lower for RE than for SE but still offers significant control over the degradation of perchlorate under full-scale conditions.

  10. High-density mammalian cell cultures in stirred-tank bioreactor without external pH control.

    PubMed

    Xu, Sen; Chen, Hao

    2016-08-10

    Maintaining desired pH is a necessity for optimal cell growth and protein production. It is typically achieved through a two-sided pH control loop on the bioreactor controller. Here we investigated cell culture processes with minimum or no pH control and demonstrated that high-density mammalian cell cultures could be maintained for long-term protein production without pH control. The intrinsic interactions between pCO2, lactate, and pH were leveraged to maintain culture pH. Fed-batch cultures at the same lower pH limit of 6.75 but different upper pH limits (7.05, 7.30, 7.45, 7.65) were evaluated in the 3L bioreactors and comparable results were obtained. Neither CO2 sparging nor base addition was required to control pH in the pH range of 6.75-7.65. The impact of sparger configurations (drilled hole sparger vs. frit sparger) and scales (3L vs. 200L) on CO2 accumulation and culture pH was also demonstrated. The same principle was applied in two perfusion cultures with steady state cell densities at 42.5±3.3 or 68.3±6.0×10(6)cells/mL with low cell specific perfusion rates (15±2 to 23±3pL/cell/day), achieving up to 1.9±0.1g/L/day bioreactor productivity. Culture pH level in the 3L perfusion bioreactors was steadily maintained by controlling the residual lactate and pCO2 levels without the requirement of external pH control for up to 40days with consistent productivity and product quality. Furthermore, culture pH could be potentially modulated via adjusting residual glucose levels and CO2 stripping capability in perfusion cultures. To the best of our knowledge, this is the first time a systematic study was performed to evaluate the long-term cell cultivation and protein production in stirred-tank bioreactors without external pH control.

  11. Stirred tank bioreactor culture combined with serum-/xenogeneic-free culture medium enables an efficient expansion of umbilical cord-derived mesenchymal stem/stromal cells.

    PubMed

    Mizukami, Amanda; Fernandes-Platzgummer, Ana; Carmelo, Joana G; Swiech, Kamilla; Covas, Dimas T; Cabral, Joaquim M S; da Silva, Cláudia L

    2016-08-01

    Mesenchymal stem/stromal cells (MSC) are being widely explored as promising candidates for cell-based therapies. Among the different human MSC origins exploited, umbilical cord represents an attractive and readily available source of MSC that involves a non-invasive collection procedure. In order to achieve relevant cell numbers of human MSC for clinical applications, it is crucial to develop scalable culture systems that allow bioprocess control and monitoring, combined with the use of serum/xenogeneic (xeno)-free culture media. In the present study, we firstly established a spinner flask culture system combining gelatin-based Cultispher(®) S microcarriers and xeno-free culture medium for the expansion of umbilical cord matrix (UCM)-derived MSC. This system enabled the production of 2.4 (±1.1) x10(5) cells/mL (n = 4) after 5 days of culture, corresponding to a 5.3 (±1.6)-fold increase in cell number. The established protocol was then implemented in a stirred-tank bioreactor (800 mL working volume) (n = 3) yielding 115 million cells after 4 days. Upon expansion under stirred conditions, cells retained their differentiation ability and immunomodulatory potential. The development of a scalable microcarrier-based stirred culture system, using xeno-free culture medium that suits the intrinsic features of UCM-derived MSC represents an important step towards a GMP compliant large-scale production platform for these promising cell therapy candidates.

  12. Comparative performance evaluation of conventional and two-phase hydrophobic stirred tank reactors for methane abatement: Mass transfer and biological considerations.

    PubMed

    Cantera, Sara; Estrada, José M; Lebrero, Raquel; García-Encina, Pedro A; Muñoz, Raúl

    2016-06-01

    This study demonstrated for the first time the capability of methanotrophs to grow inside silicone oil (SO200) and identified the optimum cultivation conditions for enrichment of hydrophobic methanotrophs (high dilution rates (D) and low CH4 transfer rates). The potential of the hydrophobic methanotrophs enriched was assessed in a single-phase stirred tank reactor (1P-STR) and in a two-phase stirred tank reactor (2P-STR). Different operational conditions were systematically evaluated in both reactors (SO200 fractions of 30 and 60 %, stirring rates of 250 and 500 rpm, and D of 0.1-0.35 day(-1) with and without biomass retention). The results showed that the TPPB only supported a superior CH4 abatement performance compared to the 1P-STR (40% enhancement at 250 rpm and 25% enhancement at 500 rpm) at a D of 0.3 day(-1) due to the retention of the biocatalytic activity inside the SO200, while the 1P-STR achieved higher elimination capacities (EC up to ≈3 times) than the TPPB under the rest of conditions tested (ECmax  = 91.1 g m(-3)  h(-1) ). Furthermore, the microscopic examination and DGGE-sequencing of the communities showed that the presence of SO200 influenced the microbial population structure, impacting on bacterial biodiversity and favoring the growth of methanotrophs such as Methylosarcina. Biotechnol. Bioeng. 2016;113: 1203-1212. © 2015 Wiley Periodicals, Inc.

  13. Effect of noise correlation on noise-induced oscillation frequency in the photosensitive Belousov-Zhabotinsky reaction in a continuous stirred tank reactor.

    PubMed

    Simakov, David S A; Pérez-Mercader, Juan

    2013-12-27

    We report on the experimental study of noise-induced oscillations in the photosensitive Ru(bpy)3(2+)-catalyzed Belousov-Zhabotinsky reaction in a continuous stirred tank reactor (CSTR). In the absence of deterministic oscillations and any external periodic forcing, oscillations appear when the system is perturbed by stochastic fluctuations in light irradiation with sufficiently high amplitude in the vicinity of the bifurcation point. The frequency distribution of the noise-induced oscillations is strongly affected by noise correlation. There is a shift of the noise-induced oscillation frequency toward higher frequencies for an intermediate range of the noise correlation exponent, indicating the occurrence of coherence resonance. Our findings indicate that, in principle, noise correlation can be used to direct chemical reactions toward certain behavior.

  14. Friction Stir Welding Development

    NASA Technical Reports Server (NTRS)

    Romine, Peter L.

    1998-01-01

    The research of this summer was a continuation of work started during the previous summer faculty fellowship period. The Friction Stir Welding process (FSW) patented by The Welding Institute (TWI), in Great Britain, has become a popular topic at the Marshall Space Flight Center over the past year. Last year it was considered a novel approach to welding but few people took it very seriously as a near term solution. However, due to continued problems with cracks in the new aluminum-lithium space shuttle external tank (ET), the friction stir process is being mobilized at full speed in an effort to mature this process for the potential manufacture of flight hardware. It is now the goal of NASA and Lockheed-Martin Corporation (LMC) to demonstrate a full-scale friction stir welding system capable of welding ET size barrel sections. The objectives this summer were: (1) Implementation and validation of the rotating dynamometer on the MSFC FSW system; (2) Collection of data for FSW process modeling efforts; (3) Specification development for FSW implementation on the vertical weld tool; (4) Controls and user interface development for the adjustable pin tool; and (5) Development of an instrumentation system for the planishing process. The projects started this summer will lead to a full scale friction stir welding system that is expected to produce a friction stir welded shuttle external tank type barrel section. The success of this could lead to the implementation of the friction stir process for manufacturing future shuttle external tanks.

  15. Data Pre-Processing Method to Remove Interference of Gas Bubbles and Cell Clusters During Anaerobic and Aerobic Yeast Fermentations in a Stirred Tank Bioreactor

    NASA Astrophysics Data System (ADS)

    Princz, S.; Wenzel, U.; Miller, R.; Hessling, M.

    2014-11-01

    One aerobic and four anaerobic batch fermentations of the yeast Saccharomyces cerevisiae were conducted in a stirred bioreactor and monitored inline by NIR spectroscopy and a transflectance dip probe. From the acquired NIR spectra, chemometric partial least squares regression (PLSR) models for predicting biomass, glucose and ethanol were constructed. The spectra were directly measured in the fermentation broth and successfully inspected for adulteration using our novel data pre-processing method. These adulterations manifested as strong fluctuations in the shape and offset of the absorption spectra. They resulted from cells, cell clusters, or gas bubbles intercepting the optical path of the dip probe. In the proposed data pre-processing method, adulterated signals are removed by passing the time-scanned non-averaged spectra through two filter algorithms with a 5% quantile cutoff. The filtered spectra containing meaningful data are then averaged. A second step checks whether the whole time scan is analyzable. If true, the average is calculated and used to prepare the PLSR models. This new method distinctly improved the prediction results. To dissociate possible correlations between analyte concentrations, such as glucose and ethanol, the feeding analytes were alternately supplied at different concentrations (spiking) at the end of the four anaerobic fermentations. This procedure yielded low-error (anaerobic) PLSR models for predicting analyte concentrations of 0.31 g/l for biomass, 3.41 g/l for glucose, and 2.17 g/l for ethanol. The maximum concentrations were 14 g/l biomass, 167 g/l glucose, and 80 g/l ethanol. Data from the aerobic fermentation, carried out under high agitation and high aeration, were incorporated to realize combined PLSR models, which have not been previously reported to our knowledge.

  16. Effect of the 6PBT stirrer eccentricity and off-bottom clearance on mixing of pseudoplastic fluid in a stirred tank

    NASA Astrophysics Data System (ADS)

    Luan, Deyu; Zhang, Shengfeng; Wei, Xing; Duan, Zhenya

    The aim of this work is to investigate the effect of the shaft eccentricity on the flow field and mixing characteristics in a stirred tank with the novel stirrer composed of perturbed six-bent-bladed turbine (6PBT). The difference between coaxial and eccentric agitations is studied using computational fluid dynamics (CFD) simulations combined with standard k-ε turbulent equations, that offer a complete image of the three-dimensional flow field. In order to determine the capability of CFD to forecast the mixing process, particle image velocimetry (PIV), which provide an accurate representation of the time-averaged velocity, was used to measure fluid velocity. The test liquid used was 1.25% (wt) xanthan gum solution, a pseudoplastic fluid with a yield stress. The comparison of the experimental and simulated mean flow fields has demonstrated that calculations based on Reynolds-averaged Navier-Stokes equations are suitable for obtaining accurate results. The effects of the shaft eccentricity and the stirrer off-bottom distance on the flow model, mixing time and mixing efficiency were extensively analyzed. It is observed that the microstructure of the flow field has a significant effect on the tracer mixing process. The eccentric agitation can lead to the flow model change and the non-symmetric flow structure, which would possess an obvious superiority of mixing behavior. Moreover, the mixing rate and mixing efficiency are dependent on the shaft eccentricity and the stirrer off-bottom distance, showing the corresponding increase of the eccentricity with the off-bottom distance. The efficient mixing process of pseudoplastic fluid stirred by 6PBT impeller is obtained with the considerably low mixing energy per unit volume when the stirrer off-bottom distance, C, is T/3 and the eccentricity, e, is 0.2. The research results provide valuable references for the improvement of pseudoplastic fluid agitation technology.

  17. A pilot-scale study of struvite precipitation in a stirred tank reactor: conditions influencing the process.

    PubMed

    Pastor, L; Mangin, D; Barat, R; Seco, A

    2008-09-01

    Currently, the two most developed techniques for recovering phosphorus from wastewater consist of the formation of calcium phosphates and struvite (MgNH(4)PO(4).6H(2)O). In this work the influence of the operational conditions on the struvite precipitation process (pH in the reactor, hydraulic retention time, and magnesium:phosphorus, nitrogen:phosphorus, and calcium:magnesium molar ratios) have been studied. Twenty-three experiments with artificial wastewater were performed in a stirred reactor. In order to obtain the pH value maintenance during the crystallization process, a fuzzy logic control has been developed. High phosphorus removal efficiencies were reliably achieved precipitating the struvite as easily dried crystals or as pellets made up of agglomerated crystals.

  18. Comprehensive clone screening and evaluation of fed-batch strategies in a microbioreactor and lab scale stirred tank bioreactor system: application on Pichia pastoris producing Rhizopus oryzae lipase

    PubMed Central

    2014-01-01

    Background In Pichia pastoris bioprocess engineering, classic approaches for clone selection and bioprocess optimization at small/micro scale using the promoter of the alcohol oxidase 1 gene (PAOX1), induced by methanol, present low reproducibility leading to high time and resource consumption. Results An automated microfermentation platform (RoboLector) was successfully tested to overcome the chronic problems of clone selection and optimization of fed-batch strategies. Different clones from Mut+P. pastoris phenotype strains expressing heterologous Rhizopus oryzae lipase (ROL), including a subset also overexpressing the transcription factor HAC1, were tested to select the most promising clones. The RoboLector showed high performance for the selection and optimization of cultivation media with minimal cost and time. Syn6 medium was better than conventional YNB medium in terms of production of heterologous protein. The RoboLector microbioreactor was also tested for different fed-batch strategies with three clones producing different lipase levels. Two mixed substrates fed-batch strategies were evaluated. The first strategy was the enzymatic release of glucose from a soluble glucose polymer by a glucosidase, and methanol addition every 24 hours. The second strategy used glycerol as co-substrate jointly with methanol at two different feeding rates. The implementation of these simple fed-batch strategies increased the levels of lipolytic activity 80-fold compared to classical batch strategies used in clone selection. Thus, these strategies minimize the risk of errors in the clone selection and increase the detection level of the desired product. Finally, the performance of two fed-batch strategies was compared for lipase production between the RoboLector microbioreactor and 5 liter stirred tank bioreactor for three selected clones. In both scales, the same clone ranking was achieved. Conclusion The RoboLector showed excellent performance in clone selection of P

  19. Optimisation of Cellulase Production by Penicillium funiculosum in a Stirred Tank Bioreactor Using Multivariate Response Surface Analysis

    PubMed Central

    de Albuquerque de Carvalho, Marcelle Lins; Carvalho, Daniele Fernandes; de Barros Gomes, Edelvio; Nobuyuki Maeda, Roberto; Melo Santa Anna, Lidia Maria; de Castro, Aline Machado; Pereira, Nei

    2014-01-01

    Increasing interest in the production of second-generation ethanol necessitates the low-cost production of enzymes from the cellulolytic complex (endoglucanases, exoglucanases, and β-glucosidases), which act synergistically in cellulose breakdown. The present work aimed to optimise a bioprocess to produce these biocatalysts from the fungus Penicillium funiculosum ATCC11797. A statistical full factorial design (FFD) was employed to determine the optimal conditions for cellulase production. The optimal composition of culture media using Avicel (10 g·L−1) as carbon source was determined to include urea (1.2 g·L−1), yeast extract (1.0 g·L−1), KH2PO4 (6.0 g·L−1), and MgSO4·7H2O (1.2 g·L−1). The growth process was performed in batches in a bioreactor. Using a different FFD strategy, the optimised bioreactor operational conditions of an agitation speed of 220 rpm and aeration rate of 0.6 vvm allowed the obtainment of an enzyme pool with activities of 508 U·L−1 for FPase, 9,204 U·L−1 for endoglucanase, and 2,395 U·L−1 for β-glucosidase. The sequential optimisation strategy was effective and afforded increased cellulase production in the order from 3.6 to 9.5 times higher than production using nonoptimised conditions. PMID:25057412

  20. Optimisation of Cellulase Production by Penicillium funiculosum in a Stirred Tank Bioreactor Using Multivariate Response Surface Analysis.

    PubMed

    de Albuquerque de Carvalho, Marcelle Lins; Carvalho, Daniele Fernandes; de Barros Gomes, Edelvio; Nobuyuki Maeda, Roberto; Melo Santa Anna, Lidia Maria; de Castro, Aline Machado; Pereira, Nei

    2014-01-01

    Increasing interest in the production of second-generation ethanol necessitates the low-cost production of enzymes from the cellulolytic complex (endoglucanases, exoglucanases, and β-glucosidases), which act synergistically in cellulose breakdown. The present work aimed to optimise a bioprocess to produce these biocatalysts from the fungus Penicillium funiculosum ATCC11797. A statistical full factorial design (FFD) was employed to determine the optimal conditions for cellulase production. The optimal composition of culture media using Avicel (10 g·L(-1)) as carbon source was determined to include urea (1.2 g·L(-1)), yeast extract (1.0 g·L(-1)), KH2PO4 (6.0 g·L(-1)), and MgSO4 ·7H2O (1.2 g·L(-1)). The growth process was performed in batches in a bioreactor. Using a different FFD strategy, the optimised bioreactor operational conditions of an agitation speed of 220 rpm and aeration rate of 0.6 vvm allowed the obtainment of an enzyme pool with activities of 508 U·L(-1) for FPase, 9,204 U·L(-1) for endoglucanase, and 2,395 U·L(-1) for β-glucosidase. The sequential optimisation strategy was effective and afforded increased cellulase production in the order from 3.6 to 9.5 times higher than production using nonoptimised conditions.

  1. Production in stirred-tank bioreactor of recombinant bovine chymosin B by a high-level expression transformant clone of Pichia pastoris.

    PubMed

    Noseda, Diego Gabriel; Recúpero, Matías; Blasco, Martín; Bozzo, Joaquín; Galvagno, Miguel Ángel

    2016-07-01

    An intense screening of Pichia pastoris clones transformed with the gene of bovine chymosin under methanol-inducible AOX1 promoter was performed, obtaining a transformant clone with a higher milk-clotting activity value in comparison with our previous studies. The scaling of recombinant-chymosin production was carried out by a fed-batch strategy in a stirred-tank bioreactor using biodiesel-byproduct crude glycerol as the carbon source and pure methanol for the induction of chymosin expression, achieving a biomass concentration of 158 g DCW/L and a maximum coagulant activity of 192 IMCU/ml after 120 h of methanol induction. Recombinant bovine chymosin was purified from bioreactor-fermentation culture by a procedure including anion-exchange chromatography which allowed obtaining heterologous chymosin with high level of purity and activity; suggesting that this downstream step could be scaled up in a successful manner for chymosin purification. Thermoestability assay permitted to establish that unformulated recombinant chymosin could be stored at 5 °C without decrease of enzyme activity throughout at least 120 days. Finally, reiterative methanol-inductions of recombinant chymosin expression in bioreactor demonstrated that the reutilization of cell biomass overcame the low enzyme productivity usually reached by P. pastoris system.

  2. Determination of Noncovalent Binding Using a Continuous Stirred Tank Reactor as a Flow Injection Device Coupled to Electrospray Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Santos, Inês C.; Waybright, Veronica B.; Fan, Hui; Ramirez, Sabra; Mesquita, Raquel B. R.; Rangel, António O. S. S.; Fryčák, Petr; Schug, Kevin A.

    2015-07-01

    Described is a new method based on the concept of controlled band dispersion, achieved by hyphenating flow injection analysis with ESI-MS for noncovalent binding determinations. A continuous stirred tank reactor (CSTR) was used as a FIA device for exponential dilution of an equimolar host-guest solution over time. The data obtained was treated for the noncovalent binding determination using an equimolar binding model. Dissociation constants between vancomycin and Ac-Lys(Ac)-Ala-Ala-OH peptide stereoisomers were determined using both the positive and negative ionization modes. The results obtained for Ac- L-Lys(Ac)- D-Ala- D-Ala (a model for a Gram-positive bacterial cell wall) binding were in reasonable agreement with literature values made by other mass spectrometry binding determination techniques. Also, the developed method allowed the determination of dissociation constants for vancomycin with Ac- L-Lys(Ac)- D-Ala- L-Ala, Ac- L-Lys(Ac)- L-Ala- D-Ala, and Ac- L-Lys(Ac)- L-Ala- L-Ala. Although some differences in measured binding affinities were noted using different ionization modes, the results of each determination were generally consistent. Differences are likely attributable to the influence of a pseudo-physiological ammonium acetate buffer solution on the formation of positively- and negatively-charged ionic complexes.

  3. Spatially-resolved current and impedance analysis of a stirred tank reactor and serpentine fuel cell flow-field at low relative humidity

    NASA Astrophysics Data System (ADS)

    Hogarth, Warren H. J.; Steiner, Johannes; Benziger, Jay B.; Hakenjos, Alex

    A 20 cm 2 segmented anode fuel cell is used to investigate the performance of a hydrogen-air fuel cell at 1 atm. with two different flow-fields using spatially-resolved current and impedance measurements. A self-draining stirred tank reactor (STR) fuel cell and a single-channel serpentine fuel cell are compared with humidified and dry feed conditions. The current density distribution, impedance distribution, heat distribution and water evolution are compared for the two different flow-fields. With inlet feed dew points of 30 °C, the STR fuel cell and serpentine system performed comparably with moderate current gradients. With drier feeds, however, the STR fuel cell exhibited superior overall performance in terms of a higher total current and lower current, impedance and temperature distribution gradients. The STR fuel cell design is superior to a single-channel serpentine design under dry conditions because its open channel design allows the feed gases to mix with the product water and auto-humidify the cell.

  4. Coproduction of hydrogen and methane via anaerobic fermentation of cornstalk waste in continuous stirred tank reactor integrated with up-flow anaerobic sludge bed.

    PubMed

    Cheng, Xi-Yu; Li, Qian; Liu, Chun-Zhao

    2012-06-01

    A 10 L continuous stirred tank reactor (CSTR) system was developed for a two-stage hydrogen fermentation process with an integrated alkaline treatment. The maximum hydrogen production rate reached 218.5 mL/L h at a cornstalk concentration of 30 g/L, and the total hydrogen yield and volumetric hydrogen production rate reached 58.0 mL/g-cornstalk and 0.55-0.57 L/L d, respectively. A 10 L up-flow anaerobic sludge bed (UASB) was used for continuous methane fermentation of the effluents obtained from the two-stage hydrogen fermentation. At the optimal organic loading rate of 15.0 g-COD/Ld, the COD removal efficiency and volumetric biogas production rate reached 83.3% and 4.6L/Ld, respectively. Total methane yield reached 200.9 mL/g-cornstalk in anaerobic fermentation with the effluents and alkaline hydrolysate. As a result, the total energy recovery by coproduction of hydrogen and methane with anaerobic fermentation of cornstalk reached 67.1%.

  5. Defluoridation of drinking water by electrocoagulation/electroflotation in a stirred tank reactor with a comparative performance to an external-loop airlift reactor.

    PubMed

    Essadki, A H; Gourich, B; Vial, Ch; Delmas, H; Bennajah, M

    2009-09-15

    Defluoridation using batch electrocoagulation/electroflotation (EC/EF) was carried out in two reactors for comparison purpose: a stirred tank reactor (STR) close to a conventional EC cell and an external-loop airlift reactor (ELAR) that was recently described as an innovative reactor for EC. The respective influences of current density, initial concentration and initial pH on the efficiency of defluoridation were investigated. The same trends were observed in both reactors, but the efficiency was higher in the STR at the beginning of the electrolysis, whereas similar values were usually achieved after 15min operation. The influence of the initial pH was explained using the analyses of sludge composition and residual soluble aluminum species in the effluents, and it was related to the prevailing mechanisms of defluoridation. Fluoride removal and sludge reduction were both favored by an initial pH around 4, but this value required an additional pre-treatment for pH adjustment. Finally, electric energy consumption was similar in both reactors when current density was lower than 12mA/cm(2), but mixing and complete flotation of the pollutants were achieved without additional mechanical power in the ELAR, using only the overall liquid recirculation induced by H(2) microbubbles generated by water electrolysis, which makes subsequent treatments easier to carry out.

  6. Effect of organic loading rate on dark fermentative hydrogen production in the continuous stirred tank reactor and continuous mixed immobilized sludge reactor from waste pastry hydrolysate.

    PubMed

    Han, Wei; Hu, Yunyi; Li, Shiyi; Nie, Qiulin; Zhao, Hongting; Tang, Junhong

    2016-12-01

    Waste pastry (6%, w/v) was hydrolyzed by the produced glucoamylase and protease to obtain the glucose (19.8g/L) and free amino nitrogen (179mg/L) solution. Then, the effect of organic loading rate (OLR) (8-40kgCOD/(m(3)d)) on dark fermentative hydrogen production in the continuous stirred tank reactor (CSTR) and continuous mixed immobilized sludge reactor (CMISR) from waste pastry hydrolysate was investigated and compared. The maximum hydrogen production rate of CSTR (277.76mL/(hL)) and CMISR (320.2mL/(hL)) were achieved at OLR of 24kgCOD/(m(3)d) and 32kgCOD/(m(3)d), respectively. Carbon recovery ranged from 75.2-84.1% in the CSTR and CMISR with the balance assumed to be converted to biomass. One gram waste pastry could produce 0.33g (1.83mmol) glucose which could be further converted to 79.24mL (3.54mmol) hydrogen in the CMISR or 91.66mL (4.09mmol) hydrogen in the CSTR. This is the first study which reports dark fermentative hydrogen production from waste pastry.

  7. A comparison of orbitally-shaken and stirred-tank bioreactors: pH modulation and bioreactor type affect CHO cell growth and protein glycosylation.

    PubMed

    Monteil, Dominique T; Juvet, Valentin; Paz, Jonathan; Moniatte, Marc; Baldi, Lucia; Hacker, David L; Wurm, Florian M

    2016-09-01

    Orbitally shaken bioreactors (OSRs) support the suspension cultivation of animal cells at volumetric scales up to 200 L and are a potential alternative to stirred-tank bioreactors (STRs) due to their rapid and homogeneous mixing and high oxygen transfer rate. In this study, a Chinese hamster ovary cell line producing a recombinant antibody was cultivated in a 5 L OSR and a 3 L STR, both operated with or without pH control. Effects of bioreactor type and pH control on cell growth and metabolism and on recombinant protein production and glycosylation were determined. In pH-controlled bioreactors, the glucose consumption and lactate production rates were higher relative to cultures grown in bioreactors without pH control. The cell density and viability were higher in the OSRs than in the STRs, either with or without pH control. Volumetric recombinant antibody yields were not affected by the process conditions, and a glycan analysis of the antibody by mass spectrometry did not reveal major process-dependent differences in the galactosylation index. The results demonstrated that OSRs are suitable for recombinant protein production from suspension-adapted animal cells. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1174-1180, 2016.

  8. Remediation of a mixture of analgesics in a stirred-tank photobioreactor using microalgal-bacterial consortium coupled with attempt to valorise the harvested biomass.

    PubMed

    Ismail, Maha M; Essam, Tamer M; Ragab, Yasser M; El-Sayed, Abo El-Khair B; Mourad, Fathia E

    2017-05-01

    An artificial microalgal-bacterial consortium was used to remediate a mixture of analgesics (ketoprofen, paracetamol and aspirin) in a stirred-tank photobioreactor. A hydraulic retention time (HRT) of 3days supported poor treatment because of the formation of p-aminophenol (paracetamol toxic metabolite). Increasing the HRT to 4days enhanced the bioremediation efficiency. After applying an acclimatization regime, 95% removal of the analgesics mixture, p-aminophenol and COD reduction were achieved. However, shortening the HRT again to 3days neither improved the COD reduction nor ketoprofen removal. Applying continuous illumination achieved the best analgesics removal results. The harvested biomass contained 50% protein, which included almost all essential amino acids. The detected fatty acid profile suggested the harvested biomass to be a good biodiesel-producing candidate. The water-extractable fraction possessed the highest phenolic content and antioxidant capacity. These findings suggest the whole process to be an integrated eco-friendly and cost-efficient strategy for remediating pharmaceutical wastewater.

  9. Characterization of dissolved organic matter in full scale continuous stirred tank biogas reactors using ultrahigh resolution mass spectrometry: a qualitative overview.

    PubMed

    Yekta, Sepehr Shakeri; Gonsior, Michael; Schmitt-Kopplin, Philippe; Svensson, Bo H

    2012-11-20

    Dissolved organic matter (DOM) was characterized in eight full scale continuous stirred tank biogas reactors (CSTBR) using solid-phase extraction and electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FT-ICR-MS). An overview of the DOM molecular complexity in the samples from biogas reactors with conventional operational conditions and various substrate profiles is provided by assignments of unambiguous exact molecular formulas for each measured mass peak. Analysis of triplicate samples for each reactor demonstrated the reproducibility of the solid-phase extraction procedure and ESI-FT-ICR-MS which allowed precise evaluation of the DOM molecular differences among the different reactors. Cluster analysis on mass spectrometric data set showed that the biogas reactors treating sewage sludge had distinctly different DOM characteristics compared to the codigesters treating a combination of organic wastes. Furthermore, the samples from thermophilic and mesophilic codigesters had different DOM composition in terms of identified masses and corresponding intensities. Despite the differences, the results demonstrated that compositionally linked organic compounds comprising 28-59% of the total number of assigned formulas for the samples were shared in all the reactors. This suggested that the shared assigned formulas in studied CSTBRs might be related to common biochemical transformation in anaerobic digestion process and therefore, performance of the CSTBRs.

  10. Hydrolysis-acidogenesis of food waste in solid-liquid-separating continuous stirred tank reactor (SLS-CSTR) for volatile organic acid production.

    PubMed

    Karthikeyan, Obulisamy Parthiba; Selvam, Ammaiyappan; Wong, Jonathan W C

    2016-01-01

    The use of conventional continuous stirred tank reactor (CSTR) can affect the methane (CH4) recovery in a two-stage anaerobic digestion of food waste (FW) due to carbon short circuiting in the hydrolysis-acidogenesis (Hy-Aci) stage. In this research, we have designed and tested a solid-liquid-separating CSTR (SLS-CSTR) for effective Hy-Aci of FW. The working conditions were pH 6 and 9 (SLS-CSTR-1 and -2, respectively); temperature-37°C; agitation-300rpm; and organic loading rate (OLR)-2gVSL(-1)day(-1). The volatile fatty acids (VFA), enzyme activities and bacterial population (by qPCR) were determined as test parameters. Results showed that the Hy-Aci of FW at pH 9 produced ∼35% excess VFA as compared to that at pH 6, with acetic and butyric acids as major precursors, which correlated with the high enzyme activities and low lactic acid bacteria. The design provided efficient solid-liquid separation there by improved the organic acid yields from FW.

  11. Determination of Noncovalent Binding Using a Continuous Stirred Tank Reactor as a Flow Injection Device Coupled to Electrospray Ionization Mass Spectrometry.

    PubMed

    Santos, Inês C; Waybright, Veronica B; Fan, Hui; Ramirez, Sabra; Mesquita, Raquel B R; Rangel, António O S S; Fryčák, Petr; Schug, Kevin A

    2015-07-01

    Described is a new method based on the concept of controlled band dispersion, achieved by hyphenating flow injection analysis with ESI-MS for noncovalent binding determinations. A continuous stirred tank reactor (CSTR) was used as a FIA device for exponential dilution of an equimolar host-guest solution over time. The data obtained was treated for the noncovalent binding determination using an equimolar binding model. Dissociation constants between vancomycin and Ac-Lys(Ac)-Ala-Ala-OH peptide stereoisomers were determined using both the positive and negative ionization modes. The results obtained for Ac-L-Lys(Ac)-D-Ala-D-Ala (a model for a Gram-positive bacterial cell wall) binding were in reasonable agreement with literature values made by other mass spectrometry binding determination techniques. Also, the developed method allowed the determination of dissociation constants for vancomycin with Ac-L-Lys(Ac)-D-Ala-L-Ala, Ac-L-Lys(Ac)-L-Ala-D-Ala, and Ac-L-Lys(Ac)-L-Ala-L-Ala. Although some differences in measured binding affinities were noted using different ionization modes, the results of each determination were generally consistent. Differences are likely attributable to the influence of a pseudo-physiological ammonium acetate buffer solution on the formation of positively- and negatively-charged ionic complexes.

  12. Submerged fermentation of the edible mushroom Pleurotus ostreatus in a batch stirred tank bioreactor as a promising alternative for the effective production of bioactive metabolites.

    PubMed

    Papaspyridi, Lefki-Maria; Aligiannis, Nektarios; Topakas, Evangelos; Christakopoulos, Paul; Skaltsounis, Alexandros-Leandros; Fokialakis, Nikolas

    2012-03-06

    The aim of this study was to investigate the potential of the submerged fermentation procedure in the production of bioactive metabolites of the common edible mushroom Pleurotus ostreatus. The biomass of the mushroom strain was produced by submerged fermentation in a batch stirred tank bioreactor and extracted by solvents of increasing polarity. The dichloromethane and methanol extract were fractioned by different techniques including Adsorption Chromatography and Fast Centrifugal Partition Chromatography (FCPC). The structures of pure compounds were elucidated with 1D/2D NMR-spectroscopic analyses, and chemical correlations combined with GC/MS and LC/MS experiments. Nineteen metabolites (e.g., fatty acids, phenolic metabolites, nucleotides and alkaloids) were isolated. Beyond the production of known metabolites, we report herein the production also of trans-3,4-dihydro-3,4,8-trihydroxynapthalen-1(2H)-one, indolo-3-carboxylic acid, 3-formylpyrrole and 4-hydroxybenzoic acid, that have pharmaceutical interest and are isolated for the first time from Pleurotus strains. This work indicates the great potential of the established bioprocess for the production of P. ostreatus mycelia with enhanced metabolic profile.

  13. Removal of oxytetracycline (OTC) in a synthetic pharmaceutical wastewater by a sequential anaerobic multichamber bed reactor (AMCBR)/completely stirred tank reactor (CSTR) system: biodegradation and inhibition kinetics.

    PubMed

    Sponza, Delia Teresa; Çelebi, Hakan

    2012-01-01

    An anaerobic multichamber bed reactor (AMCBR) was effective in removing both molasses-chemical oxygen demand (COD), and the antibiotic oxytetracycline (OTC). The maximum COD and OTC removals were 99% in sequential AMCBR/completely stirred tank reactor (CSTR) at an OTC concentration of 300 mg L(-1). 51%, 29% and 9% of the total volatile fatty acid (TVFA) was composed of acetic, propionic acid and butyric acids, respectively. The OTC loading rates at between 22.22 and 133.33 g OTC m(-3) d(-1) improved the hydrolysis of molasses-COD (k), the maximum specific utilization of molasses-COD (k(mh)) and the maximum specific utilization rate of TVFA (k(TVFA)). The direct effect of high OTC loadings (155.56 and -177.78 g OTC m(-3) d(-1)) on acidogens and methanogens were evaluated with Haldane inhibition kinetic. A significant decrease of the Haldane inhibition constant was indicative of increases in toxicity at increasing loading rates.

  14. Influence of Light Intensity and Temperature on Cultivation of Microalgae Desmodesmus Communis in Flasks and Laboratory-Scale Stirred Tank Photobioreactor

    NASA Astrophysics Data System (ADS)

    Vanags, J.; Kunga, L.; Dubencovs, K.; Galvanauskas, V.; Grīgs, O.

    2015-04-01

    Optimization of the microalgae cultivation process and of the bioprocess in general traditionally starts with cultivation experiments in flasks. Then the scale-up follows, when the process from flasks is transferred into a laboratory-scale bioreactor, in which further experiments are performed before developing the process in a pilot-scale reactor. This research was done in order to scale-up the process from a 0.4 1 shake flask to a 4.0 1 laboratory-scale stirred-tank photobioreactor for the cultivation of Desmodesmus (D.) communis microalgae. First, the effect of variation in temperature (21-29 ºC) and in light intensity (200-600 μmol m-2s-1) was studied in the shake-flask experiments. It was shown that the best results (the maximum biomass concentration of 2.72 g 1-1 with a specific growth rate of 0.65 g g-1d-1) can be achieved at the cultivation temperature and light intensity being 25 °C and 300 μmol m2s-1, respectively. At the same time, D. communis cultivation under the same conditions in stirred-tank photobioreactor resulted in average volumetric productivities of biomass due to the light limitation even when the light intensity was increased during the experiment (the maximum biomass productivity 0.25 g 1-1d-1; the maximum biomass concentration 1.78 g 1-1). Mikroaļģu kultivēšanas procesa optimizēšana parasti sākas ar kultivēšanas eksperimentiem kolbās. Tālāk seko procesa pārnese uz laboratorijas mēroga fotobioreaktoru, kurā tiek veikti tālāki eksperimenti, pirms tiek izveidots pilota mēroga reaktors. Šis pētījums tika veikts ar mērķi, pārnest Desmodesmus communis kultivēšanas procesu no 0.4 1 kolbas uz 4.0 1 laboratorijas fotobioreaktoru. Vispirms tika pētīta dažādu temperatūru (21-29 ºC) un gaismas intensitātes (200-600 μmol m-2s-1) ietekme uz aļģu biomasu veicot eksperimentus kolbās. Labākie rezultāti (maksimālā biomasas koncentrācija 2.72 g 1-1; īpatnējais augšanas ātrums 0.65 g g-1d-1) sasniegti, kad

  15. Photocatalytic inactivation of Flavobacterium and E. coli in water by a continuous stirred tank reactor (CSTR) fed with suspended/immobilised TiO2 medium.

    PubMed

    Cohen-Yaniv, Vered; Narkis, Nava; Armon, Robert

    2008-01-01

    A photocatalytic continuous stirred tank reactor (CSTR) was built at laboratory scale to inactivate two environmental bacteria strains (Flavobacterium and E. coli) in tap water. Several parameters were found to impact reactor efficiency. Bacterial initial concentration is an important factor in inactivation rate. After 30 minutes of irradiation at 10(8)-10(9) CFU mL(-1) starting concentration, a >5 log reduction was achieved while at 10(4)-10(6) CFU mL(-1) only a 2 log reduction was observed. Water hardness and pH have an important influence on the photocatalytic inactivation process. Soft water, with low Ca(+2) and Mg(+2) at low pH approximately 5.3 resulted in increased inactivation of Flavobacterium reaching >6 orders of magnitude reduction. E. coli and Flavobacterium at pH 5 were inactivated by 3 logs more as compared to pH 7 under similar conditions. pH below TiO2 isoelectric point (approximately 5.6) supports better contact between bacteria and anatase particles resulting in superior inactivation. TiO2 powder suspension was compared with immobilised powder in sol-gel coated glass beads in order to exclude the need for particles separation from the treated water. TiO2 suspension was more effective by 3 orders of magnitude when compared to coated glass beads. An interesting observation was found between the two bacterial strains based on their hydrophobicity/hydrophilicity balance. The more hydrophobic Flavobacterium compared to E. coli was inactivated photocatalytically by >3 logs more then E. coli in the first 30 minutes of irradiation interval. The results indicate the importance of the parameters involved in the contact between TiO2 particles and microorganisms that govern the successful inactivation rate in CSTR.

  16. Reactor models for a series of continuous stirred tank reactors with a gas-liquid-solid leaching system: Part I. Surface reaction control

    NASA Astrophysics Data System (ADS)

    Papangelakis, V. G.; Demopoulos, G. P.

    1992-12-01

    In this three-part series of articles, comprehensive three-phase steady-state hydrometallurgical reactor models of the continuous stirred tank reactor (CSTR) type are developed and applied to a commercial (pressure oxidation) process. The key features of the developed models are the coupling of both mass and heat balance equations, the description of the nonisothermal performance (autothermal) of a multistage continuous reactor, and the treatment of multimineral feed materials. The model considers only the oxidation reactions, because they mainly affect the thermal balance of the reactor. The stoichiometries and intrinsic kinetics of the heterogeneous leaching reactions, which are established via independent experiments, are the foundation of the developed model. A three-phase (g-l-s) reaction process might be controlled by either surface reaction control, i.e., the rate(s) of the heterogeneous leaching reaction(s), or by gas transfer control, i.e., the rate of transfer of the gaseous reactant into the liquid phase. In the present article (Part I), the case of surface reaction control is treated. The article addresses, in particular, the following topics: (1) it outlines the basic mass and heat balance equations which describe the performance of a multistage leaching reactor; (2) it presents a continuous function to describe the particle size distribution of the feed; and (3) it develops, on the basis of probability theory, number- and mass-particle size density functions which give the size distribution of particle populations reacting according to the surface reaction control-shrinking core model.

  17. Effects of nitrobenzene concentration and hydraulic retention time on the treatment of nitrobenzene in sequential anaerobic baffled reactor (ABR)/continuously stirred tank reactor (CSTR) system.

    PubMed

    Kuscu, Ozlem Selcuk; Sponza, Delia Teresa

    2009-04-01

    The effects of increasing nitrobenzene (NB) concentrations and hydraulic retention times (HRT) on the treatment of NB were investigated in a sequential anaerobic baffled reactor (ABR)/aerobic completely stirred tank reactor (CSTR) system. In the first step of the study, the maximum COD removal efficiencies were found as 88% and 92% at NB concentrations varying between 30 mg L(-1) and 210 mg L(-1) in ABR. The minimum COD removal efficiency was 79% at a NB concentration of 700 mg L(-1). The removal efficiency of NB was nearly 100% for all NB concentrations in the ABR reactor. The methane gas production and the methane gas percentage remained stable (1500 mL day(-1) and 48-50%, respectively) as the NB concentration was increased from 30 to 210 mg L(-1). In the second step of the study it was found that as the HRT decreased from 10.38 days to 2.5 days the COD removal efficiencies decreased slightly from 94% to 92% in the ABR. For maximum COD and NB removal efficiencies the optimum HRT was found as 2.5 days in the ABR. The total COD removal efficiency was 95% in sequential anaerobic (ABR)/aerobic (CSTR) reactor system at a minimum HRT of 1 day. When the HRT was decreased from 10.38 days to 1 day, the methane percentage decreased from 42% to 29% in an ABR reactor treating 100 mg L(-1) NB. Nitrobenzene was reduced to aniline under anaerobic conditions while aniline was mineralized to catechol with meta cleavage under aerobic conditions.

  18. Recovery of resources for advanced life support space applications: effect of retention time on biodegradation of two crop residues in a fed-batch, continuous stirred tank reactor

    NASA Technical Reports Server (NTRS)

    Strayer, R. F.; Finger, B. W.; Alazraki, M. P.; Cook, K.; Garland, J. L.

    2002-01-01

    Bioreactor retention time is a key process variable that will influence costs that are relevant to long distance space travel or long duration space habitation. However. little is known about the effects of this parameter on the microbiological treatment options that are being proposed for Advanced Life Support (ALS) systems. Two bioreactor studies were designed to examine this variable. In the first one, six retention times ranging from 1.3 to 21.3 days--were run in duplicate, 81 working-volume continuous stirred tank reactors (CSTR) that were fed ALS wheat residues. Ash-free dry weight loss, carbon mineralization, soluble TOC reduction, changes in fiber content (cellulose, hemicellulose, and lignin), bacterial numbers, and mineral recoveries were monitored. At short retention times--1.33 days--biodegradation was poor (total: 16-20%, cellulose - 12%, hemicellulose - 28%) but soluble TOC was decreased by 75-80% and recovery of major crop inorganic nutrients was adequate, except for phosphorus. A high proportion of the total bacteria (ca. 83%) was actively respiring. At the longest retention time tested, 21.3 days, biodegradation was good (total: 55-60%, cellulose ca. 70%, hemicellulose - ca. 55%) and soluble TOC was decreased by 80%. Recovery of major nutrients, except phosphorus, remained adequate. A very low proportion of total bacteria was actively respiring (ca. 16%). The second bioreactor study used potato residue to determine if even shorter retention times could be used (range 0.25-2.0 days). Although overall biodegradation deteriorated, the degradation of soluble TOC continued to be ca. 75%. We conclude that if the goal of ALS bioprocessing is maximal degradation of crop residues, including cellulose, then retention times of 10 days or longer will be needed. If the goal is to provide inorganic nutrients with the smallest volume/weight bioreactor possible, then a retention time of 1 day (or less) is sufficient.

  19. Interpreting hydrodynamic behaviour by the model of stirred tanks in series with exchanged zones: preliminary study in lab-scale trickling filters.

    PubMed

    Zeng, Ming; Soric, Audrey; Ferrasse, Jean-Henry; Roche, Nicolas

    2013-01-01

    In trickling filters for wastewater treatment, hydrodynamic behaviour is affected by the growth of biofilm on the porous medium. Therefore, modelling hydrodynamic behaviour is necessary and efficient to predict the biodegradation of pollutants. In this study, laboratory-scale trickling filters were filled with two different porous media (glass beads and plastic rings) and were fed by a synthetic substrate in batch mode. Total organic carbon (TOC) of the effluent was measured and retention time distribution (RTD) was determined by injecting NaCl. Results showed that medium had no significant effect on TOC removal rate (around 80% and 60% respectively for batch time of seven and two days). However, regarding the hydrodynamic behaviour, the effective volume ratio and hydraulic efficiency in the glass beads bed increased remarkably from 28% and 18% to 80% and 70%, respectively, with the reduction of dispersion coefficient (from 4.55 to 1.53). Moreover, the short batch time accelerated this change. Conversely, no variation of hydrodynamic behaviour in plastic rings bed was evident. Along with the feeding of synthetic substrate, biofilm concentration ranged from 1.5 to 10.1 g/L in the glass beads reactor and it achieved around 2.8 g/L in the plastic rings reactor. Hydrodynamic modelling indicated that the model of stirred tanks in series with exchanged zones fitted the experimental results well. These gave values of mobile and immobile volumes of 51 mL and 17 mL, respectively, in the glass beads filter and 25 mL and 15 mL, respectively, in the plastic rings filter.

  20. Coupling of acrylic dyeing wastewater treatment by heterogeneous Fenton oxidation in a continuous stirred tank reactor with biological degradation in a sequential batch reactor.

    PubMed

    Esteves, Bruno M; Rodrigues, Carmen S D; Boaventura, Rui A R; Maldonado-Hódar, F J; Madeira, Luís M

    2016-01-15

    This work deals with the treatment of a recalcitrant effluent, from the dyeing stage of acrylic fibres, by combination of the heterogeneous Fenton's process in a continuous stirred tank reactor (CSTR) with biological degradation in a sequential batch reactor (SBR). Three different catalysts (a commercial Fe/ZSM-5 zeolite and two distinct Fe-containing activated carbons - ACs - prepared by wet impregnation of iron acetate and iron nitrate) were employed on the Fenton's process, and afterwards a parametric study was carried out to determine the effect of the main operating conditions, namely the hydrogen peroxide feed concentration, temperature and contact time. Under the best operating conditions found, using the activated carbon impregnated with iron nitrate, 62.7% of discolouration and 39.9% of total organic carbon (TOC) reduction were achieved, at steady-state. Furthermore, a considerable increase in the effluent's biodegradability was attained (BOD5:COD ratio increased from <0.001 to 0.27 and SOUR - specific oxygen uptake rate - from <0.2 to 11.1 mg O2/(gVSS·h)), alongside a major decrease in its toxicity (from 92.1 to 94.0% of Vibrio fischeri inhibition down to 6.9-9.9%). This allowed the application of the subsequent biological degradation stage. The combination of the two processes provided a treated effluent that clearly complies with the legislated discharge limits. It was also found that the iron leaching from the three catalysts tested was very small in all runs, a crucial factor for the stability and long-term use of such materials.

  1. Aeration tank settling and real time control as a tool to improve the hydraulic capacity and treatment efficiency during wet weather: results from 7 years' full-scale operational data.

    PubMed

    Sharma, A K; Guildal, T; Thomsen, H A R; Mikkelsen, P S; Jacobsen, B N

    2013-01-01

    This paper investigates the aeration tank settling (ATS) operation in combination with real time control (RTC) as a tool for increasing the hydraulic capacity and improving the treatment efficiency of a wastewater treatment plant (WWTP) during wet weather flows. Results from 7 years' full-scale operational data at the Avedøre WWTP, Denmark, show that ATS operation in combination with RTC increases the hydraulic capacity of the treatment plant with up to 150 and 67% of the design capacity during winter and summer respectively. Compared to the conventional wet weather operation, the ATS in combination with RTC operation resulted in lower effluent concentrations for total phosphate (40-50%), suspended solids (30-60%) and chemical oxygen demand (30-50%), whereas no significant effect was observed on total nitrogen. Apart from the reduced effluent concentrations, the RTC resulted in economic savings in the form of reduced costs for electricity and green taxes. However, in very few cases the ATS operation in combination with RTC was not able to handle design capacity, and some overflows occurred at flows below the design capacity. The frequency of these overflows may increase in the future due to increased rain intensity resulting in shorter prediction time available for ATS.

  2. Aeration of groundwater at a superfund site

    SciTech Connect

    Connors, P.

    1992-07-01

    One of the promising environmental cleanup activities underway at Lawrence Livermore National Laboratory is remediation of groundwater pollution by aeration techniques at the laboratory`s Site 300. The treatment facility extracts groundwater from a shallow aquifer and contaminants are removed by spraying the water into one end of a trailer mounted, polyethylene air-sparging tank. As the water passes through the tank, it is subjected to vigorous aeration from a large blower. By the time the water reaches the other end of the sparging tank, it has been stripped of volatile organic compounds(VOCs). The VOCs are stripped into the air and then collected by passing the air through two in-series, granular, activated-carbon canisters.

  3. Thermophilic anaerobic digestion of source-sorted organic fraction of household municipal solid waste: start-up procedure for continuously stirred tank reactor.

    PubMed

    Angelidaki, Irini; Chen, Xingxing; Cui, Junbo; Kaparaju, Prasad; Ellegaard, Lars

    2006-08-01

    Two feeding strategies for start-up of continuously stirred tank reactors (CSTR) treating source-sorted organic fraction of household municipal solid waste (SS-OFMSW) at 55 degrees C were evaluated. Two reactors were started up separately with a limited amount of initial inoculum (i.e. 10% of the final volume of 3.5l) and operated in a fed batch mode until the reactors were filled (30 days). A reference reactor was filled up with 3.5l of inoculum and fed at a constant rate (11.4 g volatile solids (VS)/d). Loading at progressively increasing rate (from 1.7 to 15 gVS/d), as calculated based on an activated biomass concept, showed superior process performance compared to a fixed feed rate (5.7 gVS/d). Methane yield of 0.32 m(3)/kg VS was produced during the start-up in reactor filled at progressively increasing rate and was comparable to the reference reactor. On the contrary, significant inhibition due to volatile fatty acid (VFA) build-up, mainly due to butyrate, was noticed in the reactor filled at constant rate. Thus, low initial and progressive increasing inoculum loading rate could be used as a strategy for a successful start-up of CSTR treating SS-OFMSW as it allowed a gradual acclimation of the biomass. Lab-scale results were further reaffirmed from the start-up of a full-scale plant (7000 m(3) total capacity) which was supplied with inoculum corresponding to approx. 16% of final volume and operated in a fed batch mode until the reactors were filled (58 days). Stable biogas production with low VFA (<3 g/L; based on titration method) were noticed during the start-up period when fed at progressively increasing rate. Thus, a controlled and reliable start-up procedure was found essential, which could allow rapid process stabilization and time to focus on other technical aspects of plant operation. In addition, the influence of substrate to inoculum amount (1.5-30% TS) and temperature (5-65 degrees C) on anaerobic degradation and methane production of SS-OFMSW was

  4. USING AERATION FOR CORROSION CONTROL

    EPA Science Inventory

    Aeration is a useful drinking water treatment process. Aeration has been used to remove hydrogen sulfide, methane, radon, iron, manganese, and volatile organic contaminants (VOCs) from drinking water. Aeration is also effective in removing carbon dioxide which directly impacts ...

  5. Scale translation from shaken to diffused bubble aerated systems for lycopene production by Blakeslea trispora under stimulated conditions.

    PubMed

    Mantzouridou, Fani Th; Naziri, Eleni

    2017-03-01

    This study deals with the scale up of Blakeslea trispora culture from the successful surface-aerated shake flasks to dispersed-bubble aerated column reactor for lycopene production in the presence of lycopene cyclase inhibitor 2-methyl imidazole. Controlling the initial volumetric oxygen mass transfer coefficient (kLa) via airflow rate contributes to increasing cell mass and lycopene accumulation. Inhibitor effectiveness seems to decrease in conditions of high cell mass. Optimization of crude soybean oil (CSO), airflow rate, and 2-methyl imidazole was arranged according to central composite statistical design. The optimized levels of factors were 110.5 g/L, 2.3 vvm, and 29.5 mg/L, respectively. At this optimum setting, maximum lycopene yield (256 mg/L) was comparable or even higher to those reported in shake flasks and stirred tank reactor. 2-Methyl imidazole use at levels significantly lower than those reported for other inhibitors in the literature was successful in terms of process selectivity. CSO provides economic benefits to the process through its ability to stimulate lycopene synthesis, as an inexpensive carbon source and oxygen vector at the same time.

  6. Computational fluid dynamics (CFD) tools for investigating flow and mixing in industrial systems: The Koch-Glitsch SMX(RTM) static mixer and a three Rushton turbine stirred tank

    NASA Astrophysics Data System (ADS)

    Zalc, Jeffrey Michael

    2000-11-01

    A suite of numerical tools, encompassing both commercial software and algorithms developed over the course of this dissertation research, is implemented for a detailed analysis of laminar flow and mixing in two industrial systems. A four element SMX static mixer geometry and a batch stirred tank equipped with three Rushton turbines are considered. Computational fluid dynamics (CFD) is used to compute the fully three-dimensional flow fields over tine unstructured tetrahedral meshes; at least ten flow conditions are considered for each system. Particle tracking routines are then employed to characterize the velocity components, pressure fields, and local mixing rates. Lagrangian mixing analysis is based on the dispersion of tracer particles. The stretching of fluid elements is used to quantify mixing performance. In the SMX static mixer, CFD results are validated through comparison of computed pressure drops with experimental results reported in the literature. Flow behavior is characterized by contour plots and probability density functions of velocity components and the magnitude of the deformation tensor. It is found that the flow in the static mixer is essentially independent of flow rate up through a Reynolds number of 1, beyond which inertial effects become significant and substantial differences in the nature of the flow are observed. Computed mixing patterns exhibit self-similarity and asymptotic directionality, which are fingerprints of chaotic behavior. Statistical characterization of the partially mixed structures reveals an exponential decay of the coefficient of variance with increasing axial distance. In the three Rushton turbine stirred tank, planar velocity vectors extracted from the CFD results are compared with experimental results obtained from particle imaging velocimetry (PIV). Planar laser-induced fluorescence (PLIF) and Poincare sections are both used to expose persistent poor-mixing regions, whose sizes and shapes depend strongly on the

  7. FSW Implementation on the Space Shuttle's External Tank

    NASA Technical Reports Server (NTRS)

    Hartley, David; Smelser, Jerry W. (Technical Monitor)

    2001-01-01

    This paper presents, in viewgraph form, friction stir welding on the external tank of the Space Shuttle. The topics include: 1) Friction Stir Welding Process; 2) Implementation Status; and 3) Summary.

  8. Enhancement of oxygen mass transfer and gas holdup using palm oil in stirred tank bioreactors with xanthan solutions as simulated viscous fermentation broths.

    PubMed

    Mohd Sauid, Suhaila; Krishnan, Jagannathan; Huey Ling, Tan; Veluri, Murthy V P S

    2013-01-01

    Volumetric mass transfer coefficient (kLa) is an important parameter in bioreactors handling viscous fermentations such as xanthan gum production, as it affects the reactor performance and productivity. Published literatures showed that adding an organic phase such as hydrocarbons or vegetable oil could increase the kLa. The present study opted for palm oil as the organic phase as it is plentiful in Malaysia. Experiments were carried out to study the effect of viscosity, gas holdup, and kLa on the xanthan solution with different palm oil fractions by varying the agitation rate and aeration rate in a 5 L bench-top bioreactor fitted with twin Rushton turbines. Results showed that 10% (v/v) of palm oil raised the kLa of xanthan solution by 1.5 to 3 folds with the highest kLa value of 84.44 h(-1). It was also found that palm oil increased the gas holdup and viscosity of the xanthan solution. The kLa values obtained as a function of power input, superficial gas velocity, and palm oil fraction were validated by two different empirical equations. Similarly, the gas holdup obtained as a function of power input and superficial gas velocity was validated by another empirical equation. All correlations were found to fit well with higher determination coefficients.

  9. Enhancement of Oxygen Mass Transfer and Gas Holdup Using Palm Oil in Stirred Tank Bioreactors with Xanthan Solutions as Simulated Viscous Fermentation Broths

    PubMed Central

    Mohd Sauid, Suhaila; Huey Ling, Tan; Veluri, Murthy V. P. S.

    2013-01-01

    Volumetric mass transfer coefficient (kLa) is an important parameter in bioreactors handling viscous fermentations such as xanthan gum production, as it affects the reactor performance and productivity. Published literatures showed that adding an organic phase such as hydrocarbons or vegetable oil could increase the kLa. The present study opted for palm oil as the organic phase as it is plentiful in Malaysia. Experiments were carried out to study the effect of viscosity, gas holdup, and kLa on the xanthan solution with different palm oil fractions by varying the agitation rate and aeration rate in a 5 L bench-top bioreactor fitted with twin Rushton turbines. Results showed that 10% (v/v) of palm oil raised the kLa of xanthan solution by 1.5 to 3 folds with the highest kLa value of 84.44 h−1. It was also found that palm oil increased the gas holdup and viscosity of the xanthan solution. The kLa values obtained as a function of power input, superficial gas velocity, and palm oil fraction were validated by two different empirical equations. Similarly, the gas holdup obtained as a function of power input and superficial gas velocity was validated by another empirical equation. All correlations were found to fit well with higher determination coefficients. PMID:24350269

  10. Improvement of the conversion of polystyrene to polyhydroxyalkanoate through the manipulation of the microbial aspect of the process: a nitrogen feeding strategy for bacterial cells in a stirred tank reactor.

    PubMed

    Goff, Miriam; Ward, Patrick G; O'Connor, Kevin E

    2007-11-01

    Pseudomonas putida CA-3 has been shown to accumulate the biodegradable plastic polyhydroxyalkanoate (PHA) when fed styrene or polystyrene pyrolysis oil as the sole carbon and energy source under nitrogen limiting growth conditions (67 mg nitrogen per litre at time 0). Batch fermentation of P. putida CA-3 grown on styrene or polystyrene pyrolysis oil in a stirred tank reactor yields PHA at 30% of the cell dry weight (CDW). The feeding of nitrogen at a rate of 1mg N/l/h resulted in a 1.1-fold increase in the percentage of CDW accumulated as PHA. An increase in the rate of nitrogen feeding up to 1.5mg N/l/h resulted in further increases in the percentage of the cell dry weight composed of PHA. However, feeding rates of 1.75 and 2mg N/l/h resulted in dramatic decreases in the percentage of cell dry weight composed of PHA. Interestingly nitrogen was not detectable in the growth medium after 16 h, in any of the growth conditions tested. A higher cell density was observed in cells supplied with nitrogen and thus further increases in the overall production of PHA were observed through nitrogen feeding. The highest yield of PHA was 0.28 g PHA per g styrene supplied with a nitrogen feeding rate of 1.5mg/l/h.

  11. Evaluation and Improvement of Liquid Propellant Rocket Chugging Analysis Techniques. Part 2: a Study of Low Frequency Combustion Instability in Rocket Engine Preburners Using a Heterogeneous Stirred Tank Reactor Model. Final Report M.S. Thesis - Aug. 1987

    NASA Technical Reports Server (NTRS)

    Bartrand, Timothy A.

    1988-01-01

    During the shutdown of the space shuttle main engine, oxygen flow is shut off from the fuel preburner and helium is used to push the residual oxygen into the combustion chamber. During this process a low frequency combustion instability, or chug, occurs. This chug has resulted in damage to the engine's augmented spark igniter due to backflow of the contents of the preburner combustion chamber into the oxidizer feed system. To determine possible causes and fixes for the chug, the fuel preburner was modeled as a heterogeneous stirred tank combustion chamber, a variable mass flow rate oxidizer feed system, a constant mass flow rate fuel feed system and an exit turbine. Within the combustion chamber gases were assumed perfectly mixed. To account for liquid in the combustion chamber, a uniform droplet distribution was assumed to exist in the chamber, with mean droplet diameter determined from an empirical relation. A computer program was written to integrate the resulting differential equations. Because chamber contents were assumed perfectly mixed, the fuel preburner model erroneously predicted that combustion would not take place during shutdown. The combustion rate model was modified to assume that all liquid oxygen that vaporized instantaneously combusted with fuel. Using this combustion model, the effect of engine parameters on chamber pressure oscillations during the SSME shutdown was calculated.

  12. Anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure in a single continuously stirred tank reactor process: Limits in co-substrate ratios and organic loading rate.

    PubMed

    Rico, Carlos; Muñoz, Noelia; Rico, José Luis

    2015-01-01

    Mesophilic anaerobic co-digestion of cheese whey and the screened liquid fraction of dairy manure was investigated with the aim of determining the treatment limits in terms of the cheese whey fraction in feed and the organic loading rate. The results of a continuous stirred tank reactor that was operated with a hydraulic retention time of 15.6 days showed that the co-digestion process was possible with a cheese whey fraction as high as 85% in the feed. The efficiency of the process was similar within the range of the 15-85% cheese whey fraction. To study the effect of the increasing loading rate, the HRT was progressively shortened with the 65% cheese whey fraction in the feed. The reactor efficiency dropped as the HRT decreased but enabled a stable operation over 8.7 days of HRT. At these operating conditions, a volumetric methane production rate of 1.37 m(3) CH4 m(-3) d(-1) was achieved.

  13. Importance of reduced sulfur for the equilibrium chemistry and kinetics of Fe(II), Co(II) and Ni(II) supplemented to semi-continuous stirred tank biogas reactors fed with stillage.

    PubMed

    Shakeri Yekta, Sepehr; Lindmark, Amanda; Skyllberg, Ulf; Danielsson, Asa; Svensson, Bo H

    2014-03-30

    The objective of the present study was to assess major chemical reactions and chemical forms contributing to solubility and speciation of Fe(II), Co(II), and Ni(II) during anaerobic digestion of sulfur (S)-rich stillage in semi-continuous stirred tank biogas reactors (SCSTR). These metals are essential supplements for efficient and stable performance of stillage-fed SCSTR. In particular, the influence of reduced inorganic and organic S species on kinetics and thermodynamics of the metals and their partitioning between aqueous and solid phases were investigated. Solid phase S speciation was determined by use of S K-edge X-ray absorption near-edge spectroscopy. Results demonstrated that the solubility and speciation of supplemented Fe were controlled by precipitation of FeS(s) and formation of the aqueous complexes of Fe-sulfide and Fe-thiol. The relatively high solubility of Co (∼ 20% of total Co content) was attributed to the formation of compounds other than Co-sulfide and Co-thiol, presumably of microbial origin. Nickel had lower solubility than Co and its speciation was regulated by interactions with FeS(s) (e.g. co-precipitation, adsorption, and ion substitution) in addition to precipitation/dissolution of discrete NiS(s) phase and formation of aqueous Ni-sulfide complexes.

  14. Ce-Zr-La/Al2O3 prepared in a continuous stirred-tank reactor: a highly thermostable support for an efficient Rh-based three-way catalyst.

    PubMed

    Wang, Su-Ning; Lan, Li; Hua, Wei-Bo; Shi, Zhong-Hua; Chen, Yao-Qiang; Gong, Mao-Chu; Zhong, Lin

    2015-12-21

    Two Ce-Zr-La/Al2O3 composite oxides, CZLA-C and CZLA-B, were synthesized using a co-precipitation method in a continuous stirred-tank reactor (CSTR) and a batch reactor (BR), respectively. Two Rh-based three-way catalysts (TWCs), Rh/CZLA-C and Rh/CZLA-B were obtained by a wet-impregnation method using the two composites as the supports. The physicochemical properties of the samples before and after thermal treatment at 1000 °C were characterized by N2 adsorption-desorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), H2-temperature programmed reduction (H2-TPR) and CO chemisorption. The results indicated that CZLA-C shows higher thermal stability than CZLA-B due to a sparsely-agglomerated morphology. Compared with Rh/CZLA-B, Rh/CZLA-C displayed better reducibility and higher thermal stability and exhibited significantly higher activity in the catalytic removal of the simulated gasoline vehicle exhaust emission (NO, CO and C3H8). Our work can provide a facile and economical synthesis route to advanced support materials and catalysts for exhaust emission control.

  15. Effects of methocel A15LV, polyethylene glycol, and polyvinyl alcohol on CD13 and CD33 receptor surface content and metabolism of HL60 cells cultured in stirred tank bioreactors.

    PubMed

    McDowell, C L; Carver, R T; Papoutsakis, E T

    1998-10-20

    Flow cytometry was used to examine the effect of hydrodynamic forces in a stirred tank bioreactor on the CD13 and CD33 receptor surface content of HL60 (human promyelocytic leukemia) cells. A step increase in agitation rate from 80 to 400 rpm reduced the HL60 cell apparent growth rate and increased the CD13 receptor surface content per cell, on average, by 95%. In contrast, this step increase in agitation rate to 400 rpm decreased the CD33 receptor surface content per cell, on average, by 10%. The protective effects of 0.1% Methocel A15LV, polyethylene glycol (PEG), and polyvinyl alcohol (PVA) on CD13 and CD33 receptor surface content were examined under agitation at 300 rpm in parallel 2 L bioreactor runs. The average CD33 receptor surface content was unaffected by the presence of Methocel A15LV or PEG, while PVA had a slight protective effect. In contrast, in terms of CD13 receptor content, HL60 cells agitated at 300 rpm with Methocel A15LV, PEG, or PVA behaved like cells agitated at 80 rpm with no media additives (McDowell and Papoutsakis, 1998). That is, Methocel A15LV, PEG, and PVA prevented the transduction of mechanical forces which affect CD13 cell content. HL60 cells cultured with 0.1% A15LV, PEG or PVA under conditions of mild agitation (60 rpm) in spinner flasks exhibited glucose consumption and lactate production rates that were approximately 20% lower than values of cultures containing no additive. Under conditions of agitation at 300 rpm in the 2 L bioreactor, the presence of A15LV, PEG, and PVA reduced the HL60 glucose consumption and lactate production rates by approximately 50%. Thus, media additives can dramatically reduce lactate accumulation in agitated bioreactors due to cell growth, in addition to providing protection from cellular injury.

  16. Lawson Aerator applications on rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rangeland drills, brush hogs, Dixie harrows, tandem discs and other equipment have played an important role in treating degraded rangeland environments. The Lawson Aerator is one of the newer implements to enter the scene for rangeland improvements. The Lawson Aerator was designed as a pasture renov...

  17. Application of Box-Wilson experimental design method for 2,4-dinitrotoluene treatment in a sequential anaerobic migrating blanket reactor (AMBR)/aerobic completely stirred tank reactor (CSTR) system.

    PubMed

    Kuşçu, Özlem Selçuk; Sponza, Delia Teresa

    2011-03-15

    A sequential aerobic completely stirred tank reactor (CSTR) following the anaerobic migrating blanket reactor (AMBR) was used to treat a synthetic wastewater containing 2,4-dinitrotoluene (2,4-DNT). A Box-Wilson statistical experiment design was used to determine the effects of 2,4-DNT and the hydraulic retention times (HRTs) on 2,4-DNT and COD removal efficiencies in the AMBR reactor. The 2,4-DNT concentrations in the feed (0-280 mg/L) and the HRT (0.5-10 days) were considered as the independent variables while the 2,4-DNT and chemical oxygen demand (COD) removal efficiencies, total and methane gas productions, methane gas percentage, pH, total volatile fatty acid (TVFA) and total volatile fatty acid/bicarbonate alkalinity (TVFA/Bic.Alk.) ratio were considered as the objective functions in the Box-Wilson statistical experiment design in the AMBR. The predicted data for the parameters given above were determined from the response functions by regression analysis of the experimental data and exhibited excellent agreement with the experimental results. The optimum HRT which gave the maximum COD (97.00%) and 2,4-DNT removal (99.90%) efficiencies was between 5 and 10 days at influent 2,4-DNT concentrations 1-280 mg/L in the AMBR. The aerobic CSTR was used for removals of residual COD remaining from the AMBR, and for metabolites of 2,4-DNT. The maximum COD removal efficiency was 99% at an HRT of 1.89 days at a 2,4-DNT concentration of 239 mg/L in the aerobic CSTR. It was found that 280 mg/L 2,4-DNT transformed to 2,4-diaminotoluene (2,4-DAT) via 2-amino-4-nitrotoluene (2-A-4-NT) and 4-amino-2-nitrotoluene (4-A-2-NT) in the AMBR. The maximum 2,4-DAT removal was 82% at an HRT of 8.61 days in the aerobic CSTR. The maximum total COD and 2,4-DNT removal efficiencies were 99.00% and 99.99%, respectively, at an influent 2,4-DNT concentration of 239 mg/L and at 1.89 days of HRT in the sequential AMBR/CSTR.

  18. Surfactant effects on alpha factors in full-scale wastewater aeration systems.

    PubMed

    Rosso, D; Larson, L E; Stenstrom, M K

    2006-01-01

    Aeration is an essential process in the majority of wastewater treatment processes, and accounts for the largest fraction of plant energy costs. Aeration systems can achieve wastewater oxygenation by shearing the surface (surface aerators) or releasing bubbles at the bottom of the tank (coarse- or fine-bubble aerators). Surfactants accumulate on gas-liquid interfaces and reduce mass transfer rates. This reduction in general is larger for fine-bubble aerators. This study was conducted to evaluate mass transfer effects on the characterization and specification of aeration systems in clean and process water conditions. Tests at different interfacial turbulence regimes were analysed, showing higher gas transfer depression for lower turbulence regimes. Higher turbulence regimes can offset contamination effects, at the expense of operating efficiency. This phenomenon is characteristic of surface aerators and coarse bubble diffusers and is here discussed. The results explain the variability of alpha factors measured at small scale, due to uncontrolled energy density. Results are also reported in dimensionless empirical correlations that describe mass transfer as a function of physiochemical and geometrical characteristics of the aeration process.

  19. Aeration equipment for small depths

    NASA Astrophysics Data System (ADS)

    Sluše, Jan; Pochylý, František

    2015-05-01

    Deficit of air in water causes complications with cyanobacteria mainly in the summer months. Cyanobacteria is a bacteria that produces poison called cyanotoxin. When the concentration of cyanobacteria increases, the phenomena "algal bloom" appears, which is very toxic and may kill all the organisms. This article describes new equipment for aeration of water in dams, ponds and reservoirs with small depth. This equipment is mobile and it is able to work without any human factor because its control is provided by a GPS module. The main part of this equipment consists of a floating pump which pumps water from the surface. Another important part of this equipment is an aerator where water and air are blended. Final aeration process runs in the nozzles which provide movement of all this equipment and aeration of the water. Simulations of the flow are solved by multiphase flow with diffusion in open source program called OpenFOAM. Results will be verified by an experiment.

  20. Evaluation of aeration energy saving in two modified activated sludge processes.

    PubMed

    Lee, Ingyu; Lim, Honglae; Jung, Byunghun; Colosimo, Mark F; Kim, Hyunook

    2015-12-01

    A variety of modified activated sludge processes are widely used in wastewater treatment plants (WWTPs) for removing organics and nutrients (N and P). Since energy consumption in aeration basin accounts for the major part of the overall energy usage in WWTPs, efforts have been made to find ways to reduce aeration energy. In this study, two modified activated sludge processes in a pilot scale designed for nutrient removal were evaluated for the extent of energy saving: (1) ABA(2) process - adjusting air on/off period (i.e., with a temporal change); and (2) MB-A(2)O process - changing volume ratio of aerobic tank to anoxic tank (i.e., with a spatial change). For the 1st process, the air on/off period was fixed at 60min/45min with aerobic fraction being 0.57, while for the 2nd process, the aerobic/anoxic volume ratio was reduced from 0.58 to 0.42. The results demonstrate that the effluent COD, TN, NH4(+) and TP concentrations are acceptable while reduced aeration time/volume certainly saves significant energy consumption. To the best of our knowledge, this is 1st attempt to reduce the aeration period or aeration volume to save the aeration energy in these two modified activated sludge processes. The implication of these observations is further discussed.

  1. Ultrasonic Stir Welding

    NASA Technical Reports Server (NTRS)

    Nabors, Sammy

    2015-01-01

    NASA Marshall Space Flight Center (MSFC) developed Ultrasonic Stir Welding (USW) to join large pieces of very high-strength metals such as titanium and Inconel. USW, a solid-state weld process, improves current thermal stir welding processes by adding high-power ultrasonic (HPU) energy at 20 kHz frequency. The addition of ultrasonic energy significantly reduces axial, frictional, and shear forces; increases travel rates; and reduces wear on the stir rod, which results in extended stir rod life. The USW process decouples the heating, stirring, and forging elements found in the friction stir welding process allowing for independent control of each process element and, ultimately, greater process control and repeatability. Because of the independent control of USW process elements, closed-loop temperature control can be integrated into the system so that a constant weld nugget temperature can be maintained during welding.

  2. A new dynamic model for highly efficient mass transfer in aerated bioreactors and consequences for kLa identification.

    PubMed

    Müller, Stefan; Murray, Douglas B; Machne, Rainer

    2012-12-01

    Gas-liquid mass transfer is often rate-limiting in laboratory and industrial cultures of aerobic or autotrophic organisms. The volumetric mass transfer coefficient k(L) a is a crucial characteristic for comparing, optimizing, and upscaling mass transfer efficiency of bioreactors. Reliable dynamic models and resulting methods for parameter identification are needed for quantitative modeling of microbial growth dynamics. We describe a laboratory-scale stirred tank reactor (STR) with a highly efficient aeration system (k(L) a ≈ 570 h(-1)). The reactor can sustain yeast culture with high cell density and high oxygen uptake rate, leading to a significant drop in gas concentration from inflow to outflow (by 21%). Standard models fail to predict the observed mass transfer dynamics and to identify k(L) a correctly. In order to capture the concentration gradient in the gas phase, we refine a standard ordinary differential equation (ODE) model and obtain a system of partial integro-differential equations (PIDE), for which we derive an approximate analytical solution. Specific reactor configurations, in particular a relatively short bubble residence time, allow a quasi steady-state approximation of the PIDE system by a simpler ODE model which still accounts for the concentration gradient. Moreover, we perform an appropriate scaling of all variables and parameters. In particular, we introduce the dimensionless overall efficiency κ, which is more informative than k(L) a since it combines the effects of gas inflow, exchange, and solution. Current standard models of mass transfer in laboratory-scale aerated STRs neglect the gradient in the gas concentration, which arises from highly efficient bubbling systems and high cellular exchange rates. The resulting error in the identification of κ (and hence k(L) a) increases dramatically with increasing mass transfer efficiency. Notably, the error differs between cell-free and culture-based methods of parameter identification

  3. Two-level multivariable control system of dissolved oxygen tracking and aeration system for activated sludge processes.

    PubMed

    Piotrowski, Robert

    2015-01-01

    The problem of tracking dissolved oxygen is one of the most complex and fundamental issues related to biological processes. The dissolved oxygen level in aerobic tanks has a significant influence on the behavior and activity of microorganisms. Aerated tanks are supplied with air from an aeration system (blowers, pipes, throttling valves, and diffusers). It is a complex, dynamic system governed by nonlinear hybrid dynamics. Control of the aeration system is also difficult in terms of control of the dissolved oxygen. In this article, a two-level multivariable control system for tracking dissolved oxygen and controlling an aeration system is designed. A nonlinear model predictive control algorithm was applied to design controllers for each level. This overall hierarchical control system was validated by simulation based on real data records provided by a water resource recovery facility located in Kartuzy, Northern Poland. The effect of control system parameters and disturbances was also investigated.

  4. Microstructural investigations on aerated concrete

    SciTech Connect

    Narayanan, N.; Ramamurthy, K.

    2000-03-01

    Aerated concrete is characterized by the presence of large voids deliberately included in its matrix to reduce the density. This study reports the investigations conducted on the structure of cement-based autoclaved aerated concrete (AAC) and non-AAC with sand or fly ash as the filler. The reasons for changes in compressive strength and drying shrinkage are explained with reference to the changes in the microstructure. Compositional analysis was carried out using XRD. It was observed that fly ash responds poorly to autoclaving. The process of pore refinement in fly ash mixes is discussed with reference to the formation of Hadley grains as well as fly ash hydration. The paste-void interface in aerated concrete investigated in relation to the paste-aggregate interface in normal concrete revealed the existence of an interfacial transition zone.

  5. Stirring and mixing effects on oscillations and inhomogeneities in the minimal bromate oscillator

    NASA Astrophysics Data System (ADS)

    Dutt, A. K.; Menzinger, M.

    1999-04-01

    Stirring and mixing effects on the oscillations and inhomogeneities in the bromate-bromide-cerous system (minimal bromate oscillator) have been investigated in a continuously fed stirred tank reactor (CSTR). A movable microelectrode is used to monitor the inhomogeneities inside the CSTR in an oscillating phase. The results are explained in terms of the theory of imperfect mixing.

  6. Damage Tolerance Behavior of Friction Stir Welds in Aluminum Alloys

    NASA Technical Reports Server (NTRS)

    McGill, Preston; Burkholder, Jonathan

    2012-01-01

    Friction stir welding is a solid state welding process used in the fabrication of various aerospace structures. Self-reacting and conventional friction stir welding are variations of the friction stir weld process employed in the fabrication of cryogenic propellant tanks which are classified as pressurized structure in many spaceflight vehicle architectures. In order to address damage tolerance behavior associated with friction stir welds in these safety critical structures, nondestructive inspection and proof testing may be required to screen hardware for mission critical defects. The efficacy of the nondestructive evaluation or the proof test is based on an assessment of the critical flaw size. Test data describing fracture behavior, residual strength capability, and cyclic mission life capability of friction stir welds at ambient and cryogenic temperatures have been generated and will be presented in this paper. Fracture behavior will include fracture toughness and tearing (R-curve) response of the friction stir welds. Residual strength behavior will include an evaluation of the effects of lack of penetration on conventional friction stir welds, the effects of internal defects (wormholes) on self-reacting friction stir welds, and an evaluation of the effects of fatigue cycled surface cracks on both conventional and selfreacting welds. Cyclic mission life capability will demonstrate the effects of surface crack defects on service load cycle capability. The fracture data will be used to evaluate nondestructive inspection and proof test requirements for the welds.

  7. Reducing aeration energy consumption in a large-scale membrane bioreactor: Process simulation and engineering application.

    PubMed

    Sun, Jianyu; Liang, Peng; Yan, Xiaoxu; Zuo, Kuichang; Xiao, Kang; Xia, Junlin; Qiu, Yong; Wu, Qing; Wu, Shijia; Huang, Xia; Qi, Meng; Wen, Xianghua

    2016-04-15

    Reducing the energy consumption of membrane bioreactors (MBRs) is highly important for their wider application in wastewater treatment engineering. Of particular significance is reducing aeration in aerobic tanks to reduce the overall energy consumption. This study proposed an in situ ammonia-N-based feedback control strategy for aeration in aerobic tanks; this was tested via model simulation and through a large-scale (50,000 m(3)/d) engineering application. A full-scale MBR model was developed based on the activated sludge model (ASM) and was calibrated to the actual MBR. The aeration control strategy took the form of a two-step cascaded proportion-integration (PI) feedback algorithm. Algorithmic parameters were optimized via model simulation. The strategy achieved real-time adjustment of aeration amounts based on feedback from effluent quality (i.e., ammonia-N). The effectiveness of the strategy was evaluated through both the model platform and the full-scale engineering application. In the former, the aeration flow rate was reduced by 15-20%. In the engineering application, the aeration flow rate was reduced by 20%, and overall specific energy consumption correspondingly reduced by 4% to 0.45 kWh/m(3)-effluent, using the present practice of regulating the angle of guide vanes of fixed-frequency blowers. Potential energy savings are expected to be higher for MBRs with variable-frequency blowers. This study indicated that the ammonia-N-based aeration control strategy holds promise for application in full-scale MBRs.

  8. Friction stir welding tool

    DOEpatents

    Tolle; Charles R. , Clark; Denis E. , Barnes; Timothy A.

    2008-04-15

    A friction stir welding tool is described and which includes a shank portion; a shoulder portion which is releasably engageable with the shank portion; and a pin which is releasably engageable with the shoulder portion.

  9. Friction-Stir Processing

    DTIC Science & Technology

    2006-01-01

    fatigue results for friction stir welded 2219 aluminum in the following conditions: 1) milled, 2) milled + LPB, 3) milled + 100 hours in a salt...same alloy following friction stir processing. Increased fatigue life in 5083-H321 aluminum fusion welds It will not be possible to friction...fine grain and weld defects near the surface will be eliminated. Potential benefits include both increased corrosion resistance and fatigue life

  10. Shaken helical track bioreactors: Providing oxygen to high-density cultures of mammalian cells at volumes up to 1000 L by surface aeration with air.

    PubMed

    Zhang, Xiaowei; Stettler, Matthieu; Reif, Oscar; Kocourek, Andreas; Dejesus, Maria; Hacker, David L; Wurm, Florian M

    2008-06-01

    A new scalable reactor was developed by applying a novel mixing principle that allows the large-scale cultivation of mammalian cells simply with surface aeration using air owing to increased liquid-gas transfer compared to standard stirred-tank bioreactors. In the cylindrical vessels (50 mL-1500 L) with a helical track attached to the inside wall, the liquid moved upward onto the track as the result of orbital shaking to increase the liquid-gas interface area significantly. This typically resulted in a 5-10-fold improvement in the volumetric mass transfer coefficient (k(L)a). In a 1500-L helical track vessel with a working volume of 1000 L, a k(L)a of 10h(-1) was obtained at a shaking speed of 39 rpm. Cultivations of CHO cells in a shaken 55-L helical track bioreactor resulted in improved cell growth profiles compared to control cultures in standard systems. These results demonstrated the possibility of using these new bioreactors at scales of 1000 L or more.

  11. Aerated Lagoons. Student Manual. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Andersen, Lorri

    This student manual contains the textual material for a unit which focuses on the structural and operationally unique features of aerated lagoons. Topic areas discussed include: (1) characteristics of completely mixed aerated lagoons; (2) facultative aerated lagoons; (3) aerated oxidation ponds; (4) effects of temperature on aerated lagoons; (5)…

  12. Pilot scale experiment with MBR operated in intermittent aeration condition: analysis of biological performance.

    PubMed

    Capodici, M; Di Bella, G; Di Trapani, D; Torregrossa, M

    2015-02-01

    The effect of intermittent aeration (IA) on a MBR system was investigated. The study was aimed at analyzing different working conditions and the influence of different IA cycles on the biological performance of the MBR pilot plant, in terms of organic carbon and ammonium removal as well as extracellular polymeric substances (EPSs) production. The membrane modules were placed in a separate compartment, continuously aerated. This configuration allowed to disconnect from the filtration stage the biological phenomena occurring into the IA bioreactor. The observed results highlighted good efficiencies, in terms of organic carbon and ammonium removal. It was noticed a significant soluble microbial products (SMPs) release, likely related to the higher metabolic stress that anoxic conditions exerted on the biomass. However, the proposed configuration, with the membranes in a separate compartment, allowed to reduce the EPSs in the membrane tank even during the non-aerated phase, thus lowering fouling development.

  13. Purging dissolved oxygen by nitrogen bubble aeration

    NASA Astrophysics Data System (ADS)

    Yamashita, Tatsuya; Ando, Keita

    2016-11-01

    We apply aeration with nitrogen microbubbles to water in order to see whether oxygen gas originally dissolved in the water at one atmosphere is purged by the aeration. The concentration of dissolved oxygen (DO) is detected by a commercial DO meter. To detect the dissolved nitrogen (DN) level, we observe the growth of millimetre-sized bubbles nucleated at glass surfaces in contact with the aerated water and compare it with the Epstein-Plesset theory that accounts for DO/DN diffusions and the presence of the glass surfaces. Comparisons between the experiment and the theory suggest that the DO in the water are effectively purged by the aeration.

  14. Stirring-induced bifurcation driven by the chaotic regime in the Belousov—Zhabotinsky reaction in a CSTR

    NASA Astrophysics Data System (ADS)

    Strizhak, Peter E.

    1995-09-01

    The stirring-induced bifurcation at low stirring rate S 0 = 23 rpm of the reaction volume has been observed for the chaotic regime in the Belousov—Zhabotinsky oscillating chemical reaction (malonic acidbromatecerium(III)sulfuric acid) in a continuously stirred tank reactor in premixing mode. This bifurcation is characterized by a stepwise growth of the macroscopic spatial concentration gradients that is shown by the use of the time dependencies of the potential difference between two platinum electrodes.

  15. Tanks and Tank Troops

    DTIC Science & Technology

    1982-03-01

    operational in the Bundeswehr. These include the well-known U.S. M113 APC, the HS-30 APC, developed by the Swiss company Hispano- Suiza , as well as the...powered by the Leyland L-60 engine, and the French AMX-30, powered by the Hispano- Suiza HS-110 engine. The new Japanese STB-6 tank (ඒ") is...of all foreign series-produced tank engines. A complete tank engine replacement can be performed in four hours. The Hispano- Suiza HS-110 engine

  16. [Diurnal variations in purifying-tanks when use Pontederia cordata treating the Malodorous River water].

    PubMed

    Chen, Jian-jun; Lu, Xiao-ming; Lu, Shao-yong; Jin, Xiang-can; Huang, Min-sheng; Zhang, Yong; Zhao, Feng

    2009-12-01

    Aquatic plants (Ponsederie cordaza) were waked in two purifying-tanks to investigate the effects of illumination intensity and aeration on diurnal variations of Chla, SP, POD of Ponsederia cordaza and pH, DO, COD, NH4+ -N, TP of water from purifying-tanks when treating the malodorous river water at seven different times, another blank purifying-tank was set as a control. Comparative studies and correlation analysis of these different indicators were carried out to improve the plants working efficiency and provide scientific basis for optimal operation of plant purifying-tanks. Results showed that all indicators affected by changes of light, TP shows best correlation coefficient Cr = 0.93, p < 0.01) of physicochemical indicators and SP behaves best correlation coefficient Cr = 0.91 , p < 0.01) of plant physiology indicators in non-aeration purifying-tank;aeration is necessary as diurnal average of DO shows an increase of 0.13 mg/L by treatment of plant meanwhile 1.8 mg/L by plant with aeration,purifying-tanks with aeration got 7.1%, 6.3% higher removing rates of COD, NH4+ -N and 38% less TP removing rate than non-aeration plant purifying-tanks (p < 0.01); with aeration treatment, significant reduction of Chla, SP content (p < 0.05) and increase of POD activity (p < 0.05) observed in plants; the changes of illumination intensity and aeration can significantly affect physiological characteristics of plants and should be considered carefully and need further study when treating malodorous river water by plant purifying-tanks.

  17. Planar oscillatory stirring apparatus

    NASA Astrophysics Data System (ADS)

    Wolf, M. F.

    1985-08-01

    The present invention is directed to an apparatus for stirring materials using planar orthogonal axes oscillations. The apparatus has a movable slide plate sandwiched between two fixed parallel support plates. Pressurized air is supplied to the movable slide plate which employs a tri-arm air bearing vent structure which allows the slide plate to float and to translate between the parallel support plates. The container having a material to be stirred is secured to the upper surface of the slide plate through an aperture in the upper support plate. A motor driven eccentric shaft loosely extends into a center hole bearing of the slide plate to cause the horizontal oscillations. Novelty lies in the combination of elements which exploits the discovery that low frequency, orthogonal oscillations applied horizontally to a Bridgman crucible provides a very rigorous stirring action, comparable with and more effective by an order of magnitude than the accelerated crucible rotation technique.

  18. Planar oscillatory stirring apparatus

    NASA Technical Reports Server (NTRS)

    Wolf, M. F. (Inventor)

    1985-01-01

    The present invention is directed to an apparatus for stirring materials using planar orthogonal axes oscillations. The apparatus has a movable slide plate sandwiched between two fixed parallel support plates. Pressurized air is supplied to the movable slide plate which employs a tri-arm air bearing vent structure which allows the slide plate to float and to translate between the parallel support plates. The container having a material to be stirred is secured to the upper surface of the slide plate through an aperture in the upper support plate. A motor driven eccentric shaft loosely extends into a center hole bearing of the slide plate to cause the horizontal oscillations. Novelty lies in the combination of elements which exploits the discovery that low frequency, orthogonal oscillations applied horizontally to a Bridgman crucible provides a very rigorous stirring action, comparable with and more effective by an order of magnitude than the accelerated crucible rotation technique.

  19. High performance aerated lagoon systems

    SciTech Connect

    Rich, L.

    1999-08-01

    At a time when less money is available for wastewater treatment facilities and there is increased competition for the local tax dollar, regulatory agencies are enforcing stricter effluent limits on treatment discharges. A solution for both municipalities and industry is to use aerated lagoon systems designed to meet these limits. This monograph, prepared by a recognized expert in the field, provides methods for the rational design of a wide variety of high-performance aerated lagoon systems. Such systems range from those that can be depended upon to meet secondary treatment standards alone to those that, with the inclusion of intermittent sand filters or elements of sequenced biological reactor (SBR) technology, can also provide for nitrification and nutrient removal. Considerable emphasis is placed on the use of appropriate performance parameters, and an entire chapter is devoted to diagnosing performance failures. Contents include: principles of microbiological processes, control of algae, benthal stabilization, design for CBOD removal, design for nitrification and denitrification in suspended-growth systems, design for nitrification in attached-growth systems, phosphorus removal, diagnosing performance.

  20. Friction Stir Welding at MSFC: Kinematics

    NASA Technical Reports Server (NTRS)

    Nunes, A. C., Jr.

    2001-01-01

    In 1991 The Welding Institute of the United Kingdom patented the Friction Stir Welding (FSW) process. In FSW a rotating pin-tool is inserted into a weld seam and literally stirs the faying surfaces together as it moves up the seam. By April 2000 the American Welding Society International Welding and Fabricating Exposition featured several exhibits of commercial FSW processes and the 81st Annual Convention devoted a technical session to the process. The FSW process is of interest to Marshall Space Flight Center (MSFC) as a means of avoiding hot-cracking problems presented by the 2195 aluminum-lithium alloy, which is the primary constituent of the Lightweight Space Shuttle External Tank. The process has been under development at MSFC for External Tank applications since the early 1990's. Early development of the FSW process proceeded by cut-and-try empirical methods. A substantial and complex body of data resulted. A theoretical model was wanted to deal with the complexity and reduce the data to concepts serviceable for process diagnostics, optimization, parameter selection, etc. A first step in understanding the FSW process is to determine the kinematics, i.e., the flow field in the metal in the vicinity of the pin-tool. Given the kinematics, the dynamics, i.e., the forces, can be targeted. Given a completed model of the FSW process, attempts at rational design of tools and selection of process parameters can be made.

  1. Aerated concrete with mineral dispersed reinforcing additives

    NASA Astrophysics Data System (ADS)

    Berdov, G. I.; Ilina, L. V.; Mukhina, I. N.; Rakov, M. A.

    2015-01-01

    To guarantee the production of aerated concrete with the lowest average density while ensuring the required strength it is necessary to use a silica component with a surface area of 250-300 m2 / kg. The article presents experimental data on grinding the silica component together with clinker to the optimum dispersion. This allows increasing the strength of non-autoclaved aerated concrete up to 33%. Furthermore, the addition to aerated concrete the mixture of dispersed reinforcing agents (wollastonite, diopside) and electrolytes with multiply charged cations and anions (1% Fe2 (SO4)3; Al2 (SO4)3) provides the growth of aerated concrete strength at 30 - 75%. As a cohesive the clinker, crushed together with silica and mineral supplements should be used. This increases the strength of aerated concrete at 65% in comparing with Portland cement.

  2. Prediction of inclusion body solubilization from shaken to stirred reactors.

    PubMed

    Walther, Cornelia; Mayer, Sabrina; Trefilov, Alexandru; Sekot, Gerhard; Hahn, Rainer; Jungbauer, Alois; Dürauer, Astrid

    2014-01-01

    Inclusion bodies (IBs) were solubilized in a µ-scale system using shaking microtiter plates or a stirred tank reactor in a laboratory setting. Characteristic dimensionless numbers for mixing, the Phase number Ph and Reynolds number Re did not correlate with the kinetics and equilibrium of protein solubilization. The solubilization kinetics was independent of the mixing system, stirring or shaking rate, shaking diameter, and energy input. Good agreement was observed between the solubilization kinetics and yield on the µ-scale and laboratory setting. We show that the IB solubilization process is controlled predominantly by pore diffusion. Thus, for the process it is sufficient to keep the IBs homogeneously suspended, and additional power input will not improve the process. The high-throughput system developed on the µ-scale can predict solubilization in stirred reactors up to a factor of 500 and can therefore be used to determine optimal solubilization conditions on laboratory and industrial scale.

  3. STIR: Advanced Quantum Sensing

    DTIC Science & Technology

    2014-07-18

    STIR: Advanced Quantum Sensing Recycling unmeasured photons in a system utilizing weak measurements can substantially improve the signal-to- noise...Quantum Sensing Report Title Recycling unmeasured photons in a system utilizing weak measurements can substantially improve the signal-to-noise ratio. We...Kevin Lyons, Andrew N. Jordan, Trent M. Graham, Paul G. Kwiat. Strengthening weak- value amplification with recycled photons , Physical Review A, (08

  4. Friction Stir Weld Tools

    NASA Technical Reports Server (NTRS)

    Carter, Robert W. (Inventor); Payton, Lewis N. (Inventor)

    2007-01-01

    A friction stir weld tool sleeve is supported by an underlying support pin. The pin material is preferably selected for toughness and fracture characteristics. The pin sleeve preferably has a geometry which employs the use of an interrupted thread, a plurality of flutes and/or eccentric path to provide greater flow through. Paddles have been found to assist in imparting friction and directing plastic metal during the welding process.

  5. Friction stir weld tools

    NASA Technical Reports Server (NTRS)

    Carter, Robert W. (Inventor); Payton, Lewis N. (Inventor)

    2007-01-01

    A friction stir weld tool sleeve is supported by an underlying support pin. The pin material is preferably selected for toughness and fracture characteristics. The pin sleeve preferably has a geometry which employs the use of an interrupted thread, a plurality of flutes and/or eccentric path to provide greater flow through. Paddles have been found to assist in imparting friction and directing plastic metal during the welding process.

  6. Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Nunes, Arthur C., Jr.

    2008-01-01

    Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and promises to be an important welding process for any industries where welds of optimal quality are demanded. This article provides an introduction to the FSW process. The chief concern is the physical effect of the tool on the weld metal: how weld seam bonding takes place, what kind of weld structure is generated, potential problems, possible defects for example, and implications for process parameters and tool design. Weld properties are determined by structure, and the structure of friction stir welds is determined by the weld metal flow field in the vicinity of the weld tool. Metal flow in the vicinity of the weld tool is explained through a simple kinematic flow model that decomposes the flow field into three basic component flows: a uniform translation, a rotating solid cylinder, and a ring vortex encircling the tool. The flow components, superposed to construct the flow model, can be related to particular aspects of weld process parameters and tool design; they provide a bridge to an understanding of a complex-at-first-glance weld structure. Torques and forces are also discussed. Some simple mathematical models of structural aspects, torques, and forces are included.

  7. DESIGN INFORMATION ON FINE PORE AERATION SYSTEMS

    EPA Science Inventory

    Field studies were conducted over several years at municipal wastewater treatment plants employing line pore diffused aeration systems. These studies were designed to produce reliable information on the performance and operational requirements of fine pore devices under process ...

  8. Predicting oxygen transfer of fine bubble diffused aeration systems--model issued from dimensional analysis.

    PubMed

    Gillot, S; Capela-Marsal, S; Roustan, M; Héduit, A

    2005-04-01

    The standard oxygenation performances of fine bubble diffused aeration systems in clean water, measured in 12 cylindrical tanks (water depth from 2.4 to 6.1m), were analysed using dimensional analysis. A relationship was established to estimate the scale-up factor for oxygen transfer, the transfer number (N(T)) The transfer number, which is written as a function of the oxygen transfer coefficient (k(L)a(20)), the gas superficial velocity (U(G)), the kinematic viscosity of water (nu) and the acceleration due to gravity (g), has the same physical meaning as the specific oxygen transfer efficiency. N(T) only depends on the geometry of the tank/aeration system [the total surface of the perforated membrane (S(p)), the surface of the tank (S) or its diameter (D), the total surface of the zones covered by the diffusers ("aerated area", S(a)) and the submergence of the diffusers (h)]. This analysis allowed to better describe the mass transfer in cylindrical tanks. Within the range of the parameters considered, the oxygen transfer coefficient (k(L)a(20)) is an increasing linear function of the air flow rate. For a given air flow rate and a given tank surface area, k(L)a(20) decreases with the water depth (submergence of the diffusers). For a given water depth, k(L)a(20) increases with the number of diffusers, and, for an equal number of diffusers, with the total area of the zones covered by the diffusers. The latter result evidences the superiority of the total floor coverage over an arrangement whereby the diffusers are placed on separate grids. The specific standard oxygen transfer efficiency is independent of the air flow rate and the water depth, the drop in the k(L)a(20) being offset by the increase of the saturation concentration. For a given tank area, the impact of the total surface of the perforated membrane (S(p)) and of the aerated area (S(a)) is the same as on the oxygen transfer coefficient.

  9. Effect of Stirring Method on Protein Crystallization

    NASA Astrophysics Data System (ADS)

    Yaoi, Mari; Adachi, Hiroaki; Takano, Kazufumi; Matsumura, Hiroyoshi; Inoue, Tsuyoshi; Mori, Yusuke; Sasaki, Takatomo

    2004-10-01

    We previously proposed the use of solution stirring during the growth of protein crystals using the Micro-Stirring technique with a rotary shaker. In this paper, we report on the effects of a new type solution flow on the crystallization of hen egg-white lysozyme (HEWL) using a wave shaker. The time required for nucleation was reduced by wave stirring, but increased by rotary stirring. Nucleation was stimulated by wave stirring. This result indicates that protein crystal growth in a stirred solution is strongly dependent on the stirring method used and the solution flow. Therefore, optimized stirring conditions are essential for producing high-quality protein crystals.

  10. Biopulsing: An in situ aeration remediation strategy

    SciTech Connect

    Gupta, H.S.; Marshall, T.R.

    1997-12-31

    In situ soil aeration is an accepted technology for remediation of soil and groundwater impacted with petroleum hydrocarbons and halogenated hydrocarbons. This technology was utilized for remediating soil and groundwater at an aerospace components manufacturing facility located in southern California, Soil and groundwater had been impacted at the facility from historical releases of petroleum and halogenated hydrocarbons. Innovations in remediation system design, installation and monitoring strategies are described in this paper. The following tasks were conducted; (1) evaluation of the extent of impacted soil and groundwater; (2) collection of site-specific data necessary to evaluate and implement an appropriate remediation system to address the hydrocarbon-impacted soil; and (3) design, installation and operation of an in situ aeration system for remediation of soil and groundwater. The in situ aeration system operates on the principles of bioventing. Air was injected weekly into the subsurface by a system of wells placed at selected locations in short pulses lasting several hours. Oxygen utilization in the subsurface was monitored using subsurface sensors. Subsurface oxygen utilization rates of up to 1.5 percent resulted in an estimate of mass reduction of 71 pounds of hydrocarbons. The concentration of halogenated hydrocarbons was reduced in groundwater following commencement of aeration was observed in subsequent sampling events. The contribution of vadose zone aeration in reducing the concentrations of halogenated hydrocarbons in groundwater is currently being evaluated.

  11. Soil Aeration deficiencies in urban sites

    NASA Astrophysics Data System (ADS)

    Weltecke, Katharina; Gaertig, Thorsten

    2010-05-01

    Soil aeration deficiencies in urban sites Katharina Weltecke and Thorsten Gaertig On urban tree sites reduction of soil aeration by compaction or sealing is an important but frequently underestimated factor for tree growth. Up to 50% of the CO2 assimilated during the vegetation period is respired in the root space (Qi et al. 1994). An adequate supply of the soil with oxygen and a proper disposal of the exhaled carbon dioxide are essential for an undisturbed root respiration. If the soil surface is smeared, compacted or sealed, soil aeration is interrupted. Several references show that root activity and fine root growth are controlled by the carbon dioxide concentration in soil air (Qi et al.1994, Burton et al. 1997). Gaertig (2001) found that decreasing topsoil gas permeability leads to reduced fine root density and hence to injury in crown structure of oaks. In forest soils a critical CO2 concentration of more than 0.6 % indicates a bad aeration status (Gaertig 2001). The majority of urban tree sites are compacted or sealed. The reduction of soil aeration may lead to dysfunctions in the root space and consequently to stress during periods of drought, which has its visible affects in crown structure. It is reasonable to assume that disturbances in soil aeration lead to reduced tree vigour and roadworthiness, resulting in high maintenance costs. The assessment of soil aeration in urban sites is difficult. In natural ecosystems the measurement of gas diffusivity and the gas-chromatical analysis of CO2 in soil air are accepted procedures in analyzing the state of aeration (Schack-Kirchner et al. 2001, Gaertig 2001). It has been found that these methods can also be applied for analyzing urban sites. In particular CO2 concentration in the soil atmosphere can be considered as a rapidly assessable, relevant and integrating indicator of the aeration situation of urban soils. This study tested the working hypothesis that soil aeration deficiencies lead to a decrease of fine

  12. Landfill aeration worldwide: Concepts, indications and findings

    SciTech Connect

    Ritzkowski, M.; Stegmann, R.

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer Different landfill aeration concepts and accordant application areas are described. Black-Right-Pointing-Pointer Examples of full scale projects are provided for Europe, North-America and Asia. Black-Right-Pointing-Pointer Major project findings are summarised, including prospects and limitations. Black-Right-Pointing-Pointer Inconsistencies between laboratory and full scale results have been elaborated. Black-Right-Pointing-Pointer An explanatory approach in connection with the inconsistencies is provided. - Abstract: The creation of sustainable landfills is a fundamental goal in waste management worldwide. In this connection landfill aeration contributes towards an accelerated, controlled and sustainable conversion of conventional anaerobic landfills into a biological stabilized state associated with a minimised emission potential. The technology has been successfully applied to landfills in Europe, North America and Asia, following different strategies depending on the geographical region, the specific legislation and the available financial resources. Furthermore, methodologies for the incorporation of landfill aeration into the carbon trade mechanisms have been developed in recent years. This manuscript gives an overview on existing concepts for landfill aeration; their application ranges and specifications. For all of the described concepts examples from different countries worldwide are provided, including details regarding their potentials and limitations. Some of the most important findings from these aeration projects are summarised and future research needs have been identified. It becomes apparent that there is a great demand for a systematisation of the available results and implications in order to further develop and optimise this very promising technology. The IWWG (International Waste Working Group) Task Group 'Landfill Aeration' contributes towards the achievement of this goal.

  13. Acid mine water aeration and treatment system

    DOEpatents

    Ackman, Terry E.; Place, John M.

    1987-01-01

    An in-line system is provided for treating acid mine drainage which basically comprises the combination of a jet pump (or pumps) and a static mixer. The jet pump entrains air into the acid waste water using a Venturi effect so as to provide aeration of the waste water while further aeration is provided by the helical vanes of the static mixer. A neutralizing agent is injected into the suction chamber of the jet pump and the static mixer is formed by plural sections offset by 90 degrees.

  14. Think Tanks

    NASA Technical Reports Server (NTRS)

    2001-01-01

    A new inspection robot from Solex Robotics Systems was designed to eliminate hazardous inspections of petroleum and chemical storage tanks. The submersible robot, named Maverick, is used to inspect the bottoms of tanks, keeping the tanks operational during inspection. Maverick is able to provide services that will make manual tank inspections obsolete. While the inspection is conducted, Maverick's remote human operators remain safe outside of the tank. The risk to human health and life is now virtually eliminated. The risk to the environment is also minimal because there is a reduced chance of spillage from emptying and cleaning the tanks, where previously, tons of pollutants were released through the process of draining and refilling.

  15. Friction-Stir Welding of Aluminum For the Space Program

    NASA Technical Reports Server (NTRS)

    Jones, Clyde S.; Smelser, Jerry W. (Technical Monitor)

    2002-01-01

    The Marshall Space Flight Center is developing and characterizing the friction stir welding process for the Space Shuttle and other space programs. This revolutionary process, invented and patented by The Weld Institute in England, offers tremendous advantages for joining aluminum for high performance applications. It is particularly suited for advanced aluminum-lithium alloys, such as 2195, the primary structural alloy used in the External Tank. The friction stir welding process joins metals with minimal heat input, resulting in high-strength joints with high ductility. It is a simple process to demonstrate using a common milling machine for sample parts, but relatively expensive to implement on large-scale hardware, due to the high cost of tooling needed to handle the high forging pressures characteristic of the process. Recent developments at the Marshall Space Flight Center have demonstrated friction stir welding on linear joints up to 5 meters (15 ft.), with material thickness ranging between 2.5 mm and 16.5 mm (0.100" to 0.650"). High efficiency weld joints have been produced in aluminum from the 2000, 5000, and 6000 series alloy systems. A "retractable pin tool" system was patented by MSFC that allows use of friction stir welding for joints with changing material thickness, and with less rigid tooling than previously considered. This presentation will describe the details of alloys welded to-date and technical advances under development at MSFC. These developments could have substantial benefit to industrial applications for welding aluminum.

  16. Thermal Stir Welds in Titanium

    NASA Astrophysics Data System (ADS)

    Fonda, Richard W.; Knipling, Keith E.; Pilchak, Adam L.

    2016-01-01

    Although conventional friction stir welding (FSW) has proven unsuccessful in joining thick sections of alpha and near-alpha titanium alloys, thermal stir welding, a variant of the FSW process in which an external heat source is used to preheat the workpiece, is demonstrated to be able to reliably join 12.3-mm-thick plates of CP titanium. This paper describes the microstructures and textures that develop in these thermal stir welds. The observed microstructure was used to reconstruct the high-temperature microstructure and texture present during the welding process and therefore reveal the genesis of the welding structures.

  17. Foaming and media surfactant effects on the cultivation of animal cells in stirred and sparged bioreactors.

    PubMed

    Zhang, S; Handa-Corrigan, A; Spier, R E

    1992-09-01

    Foam formation and the subsequent cell damage/losses in the foam layer were found to be the major problems affecting cell growth and monoclonal antibody (MAb) production in stirred and sparged bioreactors for both serum-supplemented and serum-free media. Surfactants in the culture media had a profound effect on cell growth by changing both the properties of bubbles and the qualities of foam formed. Comparable cell growth and MAb production in sparged bioreactors and in stirred and surface-aerated control cultures were observed only in Pluronic F-68 containing culture media. In media devoid of Pluronic F-68, cells became more sensitive to direct bubble aeration in the presence of antifoam agent which was used to suppress foam formation. Compared with serum-supplemented medium, more severe cell damage effects were observed in serum-free medium. In addition, serum-free medium devoid of cells was partially degraded under continuous air sparging. The mechanism of this damage effect was not clear. Pluronic F-68 provided protective effect to cells but not to the medium. A theoretical model based on the surface active properties of Pluronic F-68 was proposed to account for its protective effect on cell growth. Optimum media surfactant composition in terms of maximum cell growth and minimum foam formation was proposed for stirred and sparged animal cell bioreactor.

  18. Package plant of extended aeration membrane bioreactors: a study on aeration intensity and biofouling control.

    PubMed

    Ujang, Z; Ng, S S; Nagaoka, H

    2005-01-01

    Biofouling control is important for effective process of membrane bioreactor (MBR). In this study, phenomena of biofouling for immersed type extended aeration MBR with two different anti-fouling aeration intensities were studied through a laboratory set up. The objectives of this study were (a) to observe biofouling phenomena of MBR that operates under different anti-fouling bubbling intensity, and simultaneously monitors performance of the MBR in organic carbon and nutrients removal; (b) to compare effectiveness of detergent and detergent-enzyme cleaning solutions in recovering biofouled membranes that operated in the extended aeration MBR. For MBR, which operated under continuous anti-fouling aeration, deposition and accumulation of suspended biomass on membrane surface were prohibited. However, flux loss was inescapable that biofilm layer was the main problem. Membrane cleaning was successfully carried out with detergent-enzyme mixture solutions and its effectiveness was compared with result from cleaning with just detergent solution.

  19. The Effect of Friction on Penetration in Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Rapp, Steve

    2002-01-01

    "Friction stir butt welding," as it was originally termed by Wayne Thomas and Christopher Dawes, in the early 1990s, but now commonly called "friction stir welding," has made great progress as a new welding technique. Marshall Space Flight Center has been investigating the use of FSW for assembly of the Shuttle's external fuel tank since the late 1990s and hopes to have the process in use by the summer of 2002. In FSW, a cylindrical pin tool of hardened steel, is rotated and plunged into the abutting edges of the parts to be joined. The tool is plunged into the weldment to within about .050 in of the bottom to assure full penetration. As the tool moves along the joint, the tool shoulder helps produce frictional heating, causing the material to plasticize. The metal of the two abutting plates flows from the front of the tool to the back where it cools and coalesces to form a weld in the solid phase. One quarter inch thick plates of aluminum alloy 2219 were used in this study. Two samples, each consisting of two 4 in x 12 in plates, were friction stir welded. The anvil for one sample was coated with molybdenum sulfide, while for the other sample a sheet of roughened stainless steel was placed between the anvil and the sample. The retractable pin tool was used so that the depth of the pin tool penetration could be varied. As welding proceeded, the length of the pin tool was gradually increased from the starting point. The purpose of this investigation is to find out at what point, in the down ramp, penetration occurs. Differences in root structure of the friction stir weld due to differences in anvil friction will be observed. These observations will be analyzed using friction stir weld theory.

  20. Phased array ultrasonic inspection of Friction Stir Weldments

    NASA Astrophysics Data System (ADS)

    Lamarre, André; Moles, Michael; Lupien, Vincent

    2000-05-01

    Phased array ultrasonic inspection methods have been developed for the rapid inspection of Friction Stir Weldments (FSW) on Delta rocket cryogenic tanks. A comprehensive review was performed to identify NDE methods that are suitable for the detection of defects in this new welding process. The search included a review of traditional and advanced NDE methods that were capable of demonstrating both the sensitivity and inspection rates required for this examination. This paper will discuss the theory behind phased array techniques, fundamentals of several probe designs for FSW configurations, and the advantages of using phased arrays over conventional NDE methods for this applications.

  1. Method of chaotic mixing and improved stirred tank reactors

    DOEpatents

    Muzzio, F.J.; Lamberto, D.J.

    1999-07-13

    The invention provides a method and apparatus for efficiently achieving a homogeneous mixture of fluid components by introducing said components having a Reynolds number of between about [le]1 to about 500 into a vessel and continuously perturbing the mixing flow by altering the flow speed and mixing time until homogeneity is reached. This method prevents the components from aggregating into non-homogeneous segregated regions within said vessel during mixing and substantially reduces the time the admixed components reach homogeneity. 19 figs.

  2. Method of chaotic mixing and improved stirred tank reactors

    DOEpatents

    Muzzio, Fernando J.; Lamberto, David J.

    1999-01-01

    The invention provides a method and apparatus for efficiently achieving a homogeneous mixture of fluid components by introducing said components having a Reynolds number of between about .ltoreq.1 to about 500 into a vessel and continuously perturbing the mixing flow by altering the flow speed and mixing time until homogeniety is reached. This method prevents the components from aggregating into non-homogeneous segregated regions within said vessel during mixing and substantially reduces the time the admixed components reach homogeneity.

  3. Bifurcation Phenomena in Stirred Tanks and Catalytic Reactors.

    DTIC Science & Technology

    1980-02-01

    AO-AOM IO UISIN MNIV-NDZSG MATEMATICS inEARCH CWTV 71 BIURCATION PHCHMIN S Di IT AWS AM CATALYTIC MEACOMI.(WI Pmo SO NAY. KFJI PAAS-,g-COWa...bifurcation analysis for the case of two consecutive reactions A + P + C in a CSTR and have shown secondary static branching and a rich variety of...do not readily ignite, but must be "activated" by heat treatment which rouahens the surface. (ii) Smooth wires do not oscillate and analysis of simple

  4. Improving industrial full-scale production of baker's yeast by optimizing aeration control.

    PubMed

    Blanco, Carlos A; Rayo, Julia; Giralda, José M

    2008-01-01

    This work analyzes the control of optimum dissolved oxygen of an industrial fed-batch procedure in which baker's yeast (Saccharomyces cerevisiae) is grown under aerobic conditions. Sugar oxidative metabolism was controlled by monitoring aeration, molasses flows, and yeast concentration in the propagator along the later stage of the propagation, and keeping pH and temperature under controlled conditions. A large number of fed-batch growth experiments were performed in the tank for a period of 16 h, for each of the 3 manufactured commercial products. For optimization and control of cultivations, the growth and metabolite formation were quantified through measurement of specific growth and ethanol concentration. Data were adjusted to a model of multiple lineal regression, and correlations representing dissolved oxygen as a function of aeration, molasses, yeast concentration in the broth, temperature, and pH were obtained. The actual influence of each variable was consistent with the mathematical model, further justified by significant levels of each variable, and optimum aeration profile during the yeast propagation.

  5. Modeling analysis for grout hopper waste tank

    SciTech Connect

    Lee, S. Y.; Ryans, J. M.

    2012-07-01

    The Saltstone facility at Savannah River Site (SRS) has a grout hopper tank to provide agitator stirring of the Saltstone feed materials. The tank has about 300 gallon capacity to provide a larger working volume for the grout nuclear waste slurry to be held in case of a process upset, and it is equipped with a mechanical agitator, which is intended to keep the grout in motion and agitated so that it won't start to set up. The primary objective of the work was to evaluate the flow performance for mechanical agitators to keep an adequate stirring of the feed materials and to estimate an agitator speed which provides acceptable flow performance with a 45 deg. pitched four-blade agitator. In addition, the power consumption required for the agitator operation was estimated. The modeling calculations were performed by taking two steps of the Computational Fluid Dynamics (CFD) modeling approach. A series of sensitivity calculations for different designs of agitators and operating conditions have been performed to investigate the impact of key parameters on the grout hydraulic performance in a 300-gallon hopper tank. Recommended operational guidance was developed by using the basic concept that local shear rates and flow patterns can be used as a measure of hydraulic performance and spatial stirring. Flow patterns and fluid residence time were estimated by a Lagrangian integration technique along the flow paths from the material feed inlet. (authors)

  6. Transfer number in fine bubble diffused aeration systems.

    PubMed

    Capela, S; Roustan, M; Héduit, A

    2001-01-01

    On the basis of full-scale data from 58 clean water tests performed in 26 activated sludge tanks equipped with fine bubble diffusers and of a theoretical approach, it can be stated that fine bubble aeration systems with total floor coverage arrangement provide higher kLa values and the lowest spiral liquid circulation. An efficiency criterion for oxygen transfer (NT) was defined on the basis of the dimensional analysis. The transfer number NT allows us to take account of the impact of vertical liquid circulation movements on oxygen transfer. The values of NT calculated from the results of full scale nonsteady-state clean water tests vary from 5.3 x 10(-5) to 9.1 x 10(-5) and are directly dependent upon the arrangement of air diffusers. It has been shown that the highest transfer numbers corresponded to the total floor coverage arrangement and the average calculated NT values is 7.7 x 10(-5), independently of the diffuser density and of the gas velocity, over the ranges studied. The lowest transfer numbers are obtained when the diffusers are located in separate grids, and the transfer number is reduced with increasing air flow rate.

  7. CFD model of an aerating hydrofoil

    NASA Astrophysics Data System (ADS)

    Scott, D.; Sabourin, M.; Beaulieu, S.; Papillon, B.; Ellis, C.

    2014-03-01

    Improving water quality in the tailrace below hydroelectric dams has become a priority in many river systems. In warm climates, water drawn by the turbine from deep in a reservoir can be deficient in dissolved oxygen (DO), a critical element in maintaining a healthy aquatic ecosystem. Many different solutions have been proposed in order to increase the DO levels in turbine discharge, including: turbine aeration systems (adding air to the water through either the turbine hub, the periphery or through distributed aeration in the runner blades); bubble diffusers in the reservoir or in the tailrace; aerating weirs downstream of the dams; and surface water pumps in the reservoir near the dam. There is a significant potential to increase the effectiveness of these solutions by improving the way that oxygen is introduced into the water; better distributions of bubbles will result in better oxygen transfer. In the present study, a two-phase Computational Fluid Dynamics model has been formulated using a commercial code to study the distribution of air downstream of a simple aerating hydrofoil. The two-phase model uses the Eulerian-Eulerian approach. Appropriate relations are used to model the interphase forces, including the Grace drag force model, the Favre averaged drag force and the Sato enhanced eddy viscosity. The model is validated using experimental results obtained in the water tunnel at the University of Minnesota's Saint Anthony Falls Laboratory. Results are obtained for water velocities between 5 and 10 m/s, air flow rates between 0.5 and 1.5 sL/min and for angles of attack between 0° and -8°. The results of this study show that the CFD model provides a good qualitative comparison to the experimental results by well predicting the wake location at the different flow rates and angles of attack used.

  8. Supersonic Injection of Aerated Liquid Jet

    NASA Astrophysics Data System (ADS)

    Choudhari, Abhijit; Sallam, Khaled

    2016-11-01

    A computational study of the exit flow of an aerated two-dimensional jet from an under-expanded supersonic nozzle is presented. The liquid sheet is operating within the annular flow regime and the study is motivated by the application of supersonic nozzles in air-breathing propulsion systems, e.g. scramjet engines, ramjet engines and afterburners. The simulation was conducted using VOF model and SST k- ω turbulence model. The test conditions included: jet exit of 1 mm and mass flow rate of 1.8 kg/s. The results show that air reaches transonic condition at the injector exit due to the Fanno flow effects in the injector passage. The aerated liquid jet is alternately expanded by Prandtl-Meyer expansion fan and compressed by oblique shock waves due to the difference between the back (chamber) pressure and the flow pressure. The process then repeats itself and shock (Mach) diamonds are formed at downstream of injector exit similar to those typical of exhaust plumes of propulsion system. The present results, however, indicate that the flow field of supersonic aerated liquid jet is different from supersonic gas jets due to the effects of water evaporation from the liquid sheet. The contours of the Mach number, static pressure of both cases are compared to the theory of gas dynamics.

  9. Bioreactor aeration conditions modulate growth and antigen expression during Erysipelothrix rhusiopathiae cultivation.

    PubMed

    da Silva, Adilson José; de Baptista-Neto, Alvaro; do Carmo Cilento, Maria; de Campos Giordano, Roberto; Zangirolami, Teresa Cristina

    2008-05-01

    Erysipelothrix rhusiopathiae, the causative agent of swine erysipelas, was cultivated in a 5-L stirred and aerated bioreactor under different dissolved oxygen tensions (0%, 5%, and 30% of saturation) for evaluation of the influence of oxygen on cell growth as well as on the production of the main antigenic component of the vaccine against erysipelas, a 64-69 kDa protein (SpaA). The microorganism presented different growth profiles for different aeration conditions. However, at the end of the batch cultivations, similar cell concentrations were obtained under the studied conditions. In order to maximize biomass titers and antigen production, the microorganism was cultivated in fed-batch operation mode under aerobic conditions. Under this condition, there was a fivefold increase in biomass production in comparison to the results attained in batch cultivations. To follow up antigen expression, samples collected during batch cultivations were concentrated and treated with choline for antigen extraction. Antigen expression was then assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and by murine immunization tests. It was observed a direct influence of oxygen availability upon antigen expression, which is favored in the presence of oxygen. Analysis of the samples collected throughout the fed-batch process also revealed that antigen production is growth associated.

  10. Effects of aeration method and aeration rate on greenhouse gas emissions during composting of pig feces in pilot scale.

    PubMed

    Jiang, Tao; Li, Guoxue; Tang, Qiong; Ma, Xuguang; Wang, Gang; Schuchardt, Frank

    2015-05-01

    The aim of this study was to uncover ways to mitigate greenhouse gas (GHG) emissions and reduce energy consumption during the composting process. We assessed the effects of different aeration rates (0, 0.18, 0.36, and 0.54 L/(kg dry matter (dm)·min)) and methods (continuous and intermittent) on GHG emissions. Pig feces and corn stalks were mixed at a ratio of 7:1. The composting process lasted for 10 weeks, and the compost was turned approximately every 2 weeks. Results showed that both aeration rate and method significantly affected GHG emissions. Higher aeration rates increased NH3 and N2O losses, but reduced CH4 emissions. The exception is that the CH4 emission of the passive aeration treatment was lower than that of the low aeration rate treatment. Without forced aeration, the CH4 diffusion rates in the center of the piles were very low and part of the CH4 was oxidized in the surface layer. Intermittent aeration reduced NH3 and CH4 losses, but significantly increased N2O production during the maturing periods. Intermittent aeration increased the nitrification/denitrification alternation and thus enhanced the N2O production. Forced aeration treatments had higher GHG emission rates than the passive aeration treatment. Forced aeration accelerated the maturing process, but could not improve the quality of the end product. Compared with continuous aeration, intermittent aeration could increase the O2 supply efficiency and reduced the total GHG emission by 17.8%, and this reduction increased to 47.4% when composting was ended after 36 days.

  11. Effects of aeration and internal recycle flow on nitrous oxide emissions from a modified Ludzak-Ettinger process fed with glycerol.

    PubMed

    Song, Kang; Suenaga, Toshikazu; Harper, Willie F; Hori, Tomoyuki; Riya, Shohei; Hosomi, Masaaki; Terada, Akihiko

    2015-12-01

    Nitrous oxide (N2O) is emitted from a modified Ludzak-Ettinger (MLE) process, as a primary activated sludge system, which requires mitigation. The effects of aeration rates and internal recycle flow (IRF) ratios on N2O emission were investigated in an MLE process fed with glycerol. Reducing the aeration rate from 1.5 to 0.5 L/min increased gaseous the N2O concentration from the aerobic tank and the dissolved N2O concentration in the anoxic tank by 54.4 and 53.4 %, respectively. During the period of higher aeration, the N2O-N conversion ratio was 0.9 % and the potential N2O reducers were predominantly Rhodobacter, which accounted for 21.8 % of the total population. Increasing the IRF ratio from 3.6 to 7.2 decreased the N2O emission rate from the aerobic tank and the dissolved N2O concentration in the anoxic tank by 56 and 48 %, respectively. This study suggests effective N2O mitigation strategies for MLE systems.

  12. Methodology, data collection, and data analysis for determination of water-mixing patterns induced by aerators and mixers

    USGS Publications Warehouse

    Johnson, Gary P.; Hornewer, N.J.; Robertson, D.M.; Olson, D.T.; Gioja, Josh

    2000-01-01

    The U.S. Geological Survey collected and analyzed data to describe mixing patterns induced by aerators and mixers to aid in the calibration and verification of a three-dimensional hydrodynamic model. During September 1995, three-dimensional water-velocity profiles were collected during the operation of fine-bubble and coarse-bubble aerators in a test tank at the U.S. Army Corps of Engineers Waterways Experiment Station. Three-dimensional water velocity, water-temperature, pH, dissolved oxygen concentration, and specific conductivity profiles were collected during operation of a coarse-bubble aerator in a reservoir in Schaumburg, Illinois, during summer 1996 and summer 1997, during strongly stratified and weakly stratified conditions. The effects of a submersible mixer alone and in combination with coarse-bubble aerators and a surface mixer alone also were investigated during summer 1997. The mixing patterns induced by the operation of aerators, submersible mixers, and surface mixers were described and compared with mixing patterns predicted by model simulations. Bubble-plume characteristics during tests in strongly stratified and weakly stratified conditions in the reservoir were documented and compared with characteristics simulated by different models. Lemckert and Imberger?s model simulates an entrainment rate similar to the rate measured during a test in the reservoir under strongly stratified conditions, whereas Schladow?s one-dimensional model appears to underestimate the total entrainment rate by about 50 percent. Schladow?s model was accurate during weak stratification but underestimated the radius of the plume during strong stratification. For 5 days during daylight hours, water temperature profiles were collected continuously during the operation of four aerators. Water temperatures in the reservoir were significantly affected by the operation of the aeration system. These changes were compared to simulations from a one-dimensional Dynamic Lake Model (DLM

  13. A microcarrier cell culture process for propagating rabies virus in Vero cells grown in a stirred bioreactor under fully animal component free conditions.

    PubMed

    Rourou, Samia; van der Ark, Arno; van der Velden, Tiny; Kallel, Héla

    2007-05-10

    Rabies virus strain production in Vero cells grown on Cytodex 1 in a 2 L stirred tank bioreactor and in a medium free of components of human or animal origin (VP-SFM) is described. Cell banking procedure in VP-SFM supplemented with an animal components free mixture (10%DMSO+0.1%methylcellulose) was reported and cell growth after revitalization was assessed. Vero cells exhibited growth performances (specific growth rate and cell division number) similar to that obtained in serum containing medium. To design a scalable process that is totally free of animal-derived substances, two proteases: TrypLE Select and Accutase, were assessed as an alternative to trypsin which is routinely used for cell passage. Growth performance of Vero cells grown in VP-SFM and MEM+10% fetal calf serum (FCS) over four passages and subcultivated with either TrypLE Select or Accutase was evaluated. TrypLE Select showed the best performance in terms of specific growth rate and cell division number. Kinetics of cell growth and rabies virus production (LP2061/Vero strain) were investigated in spinner flask and in a 2 L bioreactor. In spinner flask, a maximal cell density level of 1.85x10(6) cells/mL was achieved when the cells were grown in VP-SFM on 2 g/L Cytodex 1. Cell infection experiments conducted at an MOI of 0.3 and without the medium exchange step, typically needed for serum containing rabies virus production, resulted in a maximal virus titer equal to 2x10(7) (Fluorescent Focus Unit) FFU/mL. In stirred tank bioreactor, Vero cell growth in VP-SFM on 3 g/L Cytodex 1 was shown to be sensitive to the aeration mode. Sparging the culture was detrimental for cell growth, whereas cell density level was greatly enhanced when only headspace aeration was used. A cell density level of 2.6x10(6) cells/mL was obtained when the cells were grown on 3g/L Cytodex 1 and in batch culture mode. Cell infection at an MOI of 0.1 without any medium exchange, yielded a maximal rabies virus titer of 2.4x10

  14. Deformation During Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    White, Henry J.

    2002-01-01

    Friction Stir Welding (FSW) is a solid state welding process that exhibits characteristics similar to traditional metal cutting processes. The plastic deformation that occurs during friction stir welding is due to the superposition of three flow fields: a primary rotation of a radially symmetric solid plug of metal surrounding the pin tool, a secondary uniform translation, and a tertiary ring vortex flow (smoke rings) surrounding the tool. If the metal sticks to the tool, the plug surface extends down into the metal from the outer edge of the tool shoulder, decreases in diameter like a funnel, and closes up beneath the pin. Since its invention, ten years have gone by and still very little is known about the physics of the friction stir welding process. In this experiment, an H13 steel weld tool (shoulder diameter, 0.797 in; pin diameter, 0.312 in; and pin length, 0.2506 in) was used to weld three 0.255 in thick plates. The deformation behavior during friction stir welding was investigated by metallographically preparing a plan view sections of the weldment and taking Vickers hardness test in the key-hole region.

  15. Laser-Assisted Stir Welding of 25-mm-Thick HSLA-65 Plate

    NASA Astrophysics Data System (ADS)

    Williamson, Keith M.

    2002-12-01

    Laser-assisted stir welding is a hybrid process that combines energy from a laser with functional heating and mechanical energy to join materials in the solid state. The technology is an adaptation of friction stir welding which is particularly suited for joining thick plates. Aluminum plates up to 75 mm thick have been successfully joined using friction stir welding. Since joining occurs in the solid state, stir technology offers the capability for fabricating full penetration joints in thick plates with better mechanical properties and less weld distortion than is possible by fusion processes. Currently friction stir welding is being used in several industries to improve productivity, reduce weight, and increase the strength of welded structures. Examples include: (a) the aircraft/aerospace industry where stir technology is currently being used to fabricate the space shuttle's external tank as well as components of the Delta family of rockets; (b) the shipping industry where container manufacturers are using stir technology to produce lighter containers with more payload capacity; and (c) the oil industry where offshore platform manufactures are using automated stir welding plants to fabricate large panels and structures up to 16 meters long with widths as required. In all these cases, stir technology has been restricted to aluminum alloys; however, stainless and HSLA 65 steels have been recently stir welded with friction as the primary heat source. One of the difficulties in adapting stir welding to steel is tool wear aggravated by the high tool rubbing velocities needed to provide frictional heat input into the material. Early work showed that the tool shoulder reached temperatures above 1000 C and the weld seam behind the tool stayed within this temperature range for up to 25 mm behind the tool. Cross sections of stir welded samples showed that the heat-affected zone is relatively wide and follows the profile of the tool shoulder. Besides minimizing the tool

  16. Dual Tank Fuel System

    DOEpatents

    Wagner, Richard William; Burkhard, James Frank; Dauer, Kenneth John

    1999-11-16

    A dual tank fuel system has primary and secondary fuel tanks, with the primary tank including a filler pipe to receive fuel and a discharge line to deliver fuel to an engine, and with a balance pipe interconnecting the primary tank and the secondary tank. The balance pipe opens close to the bottom of each tank to direct fuel from the primary tank to the secondary tank as the primary tank is filled, and to direct fuel from the secondary tank to the primary tank as fuel is discharged from the primary tank through the discharge line. A vent line has branches connected to each tank to direct fuel vapor from the tanks as the tanks are filled, and to admit air to the tanks as fuel is delivered to the engine.

  17. Tristability in the iodate-As(III) chemical system arising from a model of stirring and mixing effects

    NASA Astrophysics Data System (ADS)

    Ganapathisubramanian, N.

    1991-08-01

    The iodate-As(III) system which exhibits bistability in an ideal continuous flow stirred tank reactor (CSTR), exhibits tristability when subjected to the mixing model of Kumpinsky and Epstein [J. Chem. Phys. 82, 53 (1985)]. The cross flow between the major and minor reactors influences the system's lower hysteresis limit more than its upper hysteresis limit.

  18. Tank Platoon

    DTIC Science & Technology

    1996-04-03

    mobility , sophisticated communications, enhanced target acquisition, lethal firepower, and effective armor protection. In combi- nation, these factors...including the platoon’s individual tank crews and OPs; the effects of terrain, weather, and movement; and the ranges of all available platoon...dismounted soldiers with automatic weapons. Likewise, enemy activity can range from an entrenched force using prepared fighting positions to a unit

  19. Think Tank.

    ERIC Educational Resources Information Center

    Governick, Heather; Wellington, Thom

    1998-01-01

    Examines the options for upgrading, replacing, and removal or closure of underground storage tanks (UST). Reveals the diverse regulatory control involving USTs, the Environmental Protection Agency's interest in pursuing violators, and stresses the need for administrators to be knowledgeable about state and local agency definitions of regulated…

  20. Microtiter plates versus stirred mini-bioreactors in biocatalysis: a scalable approach.

    PubMed

    Nunes, Mário A P; Fernandes, Pedro C B; Ribeiro, Maria H L

    2013-05-01

    To place the application of miniaturized vessels as microbioreactors on a firm footing, focus has been given to engineering characterization. Studies on this matter have mostly involved carrier-free biological systems, while support-based systems have been overlooked. The present work aims to contribute to fill in such gap. Thus, it intended to establish a robust scaled down approach to identify and optimize relevant operational conditions of naringin hydrolysis by naringinase in PVA lens-shaped particles. The influence of geometric and dynamic (viz. Reynolds number) parameters was evaluated. Naringin hydrolysis in round, flat bottom MTP proved more effective than in square, pyramidal bottom. The bioconversion at MTP and stirred tank reactors scales showed that, given the 12.5-fold scale difference was in agreement between the bioconversion rates. The external mass transfer resistances were negligible as deduced from Damkohler modulus ≤1. The bioconversion was effectively scaled-up 200-fold from shaken microtiter plates to stirred tank reactors.

  1. Peak Stir Zone Temperature During Friction Stir Processing

    DTIC Science & Technology

    2010-03-01

    processing (FSP) and friction stir welding ( FSW ) are allied technologies involving local- ized severe plastic deformation induced by the action of a...nonconsumable tool on a deformable material. In both FSP and FSW , the tool generally consists of a cylindrical shoulder portion with a projecting, concen- tric...macroscopic shape change.[2,3] Heating during FSP/ FSW is due to a combination of adiabatic deformation in a volume of material surround- ing the tool pin

  2. Structural properties of autoclaved aerated concrete masonry

    SciTech Connect

    Matthys, J.H.; Nelson, R.L.

    1999-07-01

    Autoclaved aerated concrete masonry units are manufactured from portland cement, quartz sand, water, lime, gypsum and a gas forming agent. The units are steam cured under pressure in an autoclave transforming the material into a hard calcium silicate. The autoclaved aerated concrete masonry units are large-size solid rectangular prisms which are laid using thin-bed mortar layers into masonry assemblages. The system and product are not new--patented in 1924 by Swedish architect Johan Eriksson. Over a period of 60 years this product has been used in all areas of residential and industrial construction and in virtually all climates. However, the principal locations of application have been generally outside the US Little information in the US is available on the structural properties of this product. Due to the interest in use of this product in the construction industry and the construction of production plants in the US, the Construction Research Center at the University of Texas at Arlington and Robert L. Nelson & Associates conducted a series of tests to determine some of the basic structural properties of this product. This paper presents the findings of those investigations.

  3. FOULING OF FINE PORE DIFFUSED AERATORS: AN INTER- PLANT COMPARISON

    EPA Science Inventory

    There has been increasing interest in fine pore aeration systems, along with concerned about diffuser fouling and the subsequent loss of aeration efficiency. The objective of this study was to assess the relative fouling tendency of fine bubble diffusers t nine activated sludge ...

  4. OXIDATION OF AS(III) BY AERATION AND STORAGE

    EPA Science Inventory

    A study of the effects of aeration and storage on the oxidation of arsenic(III) was undertaken at three utilities in the US to establish the engineering significance of aeration as a potential pre-treatment method for arsenic removal. The results of this study clearly establish t...

  5. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  6. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  7. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  8. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  9. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone...

  10. 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.

  11. Friction Stir Welding of Curved Plates

    NASA Technical Reports Server (NTRS)

    Sanchez, Nestor

    1999-01-01

    Friction stir welding (FSW) is a remarkable technology for making butt and lap joints in aluminum alloys. The process operates by passing a rotating tool between two closely butted plates. This process generates heat and the heated material is stirred from both sides of the plates to generate a high quality weld. Application of this technique has a very broad field for NASA. In particular, NASA is interested in using this welding process to manufacture tanks and curved elements. Therefore, this research has been oriented to the study the FSW of curved plates. The study has covered a number of topics that are important in the model development and to uncover the physical process involve in the welding itself. The materials used for the experimental welds were as close to each other as we could possibly find, aluminum 5454-0 and 5456-0 with properties listed at http://matweb.com. The application of FSW to curved plates needs to consider the behavior that we observed in this study. There is going to be larger force in the normal direction (Fz) as the curvature of the plate increases. A particular model needs to be derived for each material and thickness. A more complete study should also include parameters such as spin rate, tool velocity, and power used. The force in the direction of motion (Fx) needs to be reconsidered to make sure of its variability with respect to other parameters such as velocity, thickness, etc. It seems like the curvature does not play a role in this case. Variations in temperature were found with respect to the curvature. However, these changes seem to be smaller than the effect on Fz. The temperatures were all below the melting point. We understand now that the process of FSW produces a three dimensional flow of material that takes place during the weld. This flow needs to be study in a more detailed way to see in which directions the flow of material is stronger. It could be possible to model the flow using a 2-dimensional model in the

  12. Tank 241-U-204 tank characterization plan

    SciTech Connect

    Bell, K.E.

    1995-03-23

    This document is the tank characterization plan for Tank 241-U-204 located in the 200 Area Tank Farm on the Hanford Reservation in Richland, Washington. This plan describes Data Quality Objectives (DQO) and presents historical information and scheduled sampling events for tank 241-U-204.

  13. Friction Stir Process Mapping Methodology

    NASA Technical Reports Server (NTRS)

    Kooney, Alex; Bjorkman, Gerry; Russell, Carolyn; Smelser, Jerry (Technical Monitor)

    2002-01-01

    In FSW (friction stir welding), the weld process performance for a given weld joint configuration and tool setup is summarized on a 2-D plot of RPM vs. IPM. A process envelope is drawn within the map to identify the range of acceptable welds. The sweet spot is selected as the nominal weld schedule. The nominal weld schedule is characterized in the expected manufacturing environment. The nominal weld schedule in conjunction with process control ensures a consistent and predictable weld performance.

  14. Pulsed ultrasonic stir welding system

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    An ultrasonic stir welding system includes a welding head assembly having a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. During a welding operation, ultrasonic pulses are applied to the rod as it rotates about its longitudinal axis. The ultrasonic pulses are applied in such a way that they propagate parallel to the longitudinal axis of the rod.

  15. Flexible Friction Stir Joining Technology

    SciTech Connect

    Feng, Zhili; Lim, Yong Chae; Mahoney, Murray; Sanderson, Samuel; Larsen, Steve; Steel, Russel; Fleck, Dale; Fairchild, Doug P; Wasson, Andrew J; Babb, Jon; Higgins, Paul

    2015-07-23

    Reported herein is the final report on a U.S. Department of Energy (DOE) Advanced Manufacturing Office (AMO) project with industry cost-share that was jointly carried out by Oak Ridge National Laboratory (ORNL), ExxonMobil Upstream Research Company (ExxonMobil), and MegaStir Technologies (MegaStir). The project was aimed to advance the state of the art of friction stir welding (FSW) technology, a highly energy-efficient solid-state joining process, for field deployable, on-site fabrications of large, complex and thick-sectioned structures of high-performance and high-temperature materials. The technology innovations developed herein attempted to address two fundamental shortcomings of FSW: 1) the inability for on-site welding and 2) the inability to weld thick section steels, both of which have impeded widespread use of FSW in manufacturing. Through this work, major advance has been made toward transforming FSW technology from a “specialty” process to a mainstream materials joining technology to realize its pervasive energy, environmental, and economic benefits across industry.

  16. External Tank - The Structure Backbone

    NASA Technical Reports Server (NTRS)

    Welzyn, Kenneth; Pilet, Jeffrey C.; Diecidue-Conners, Dawn; Worden, Michelle; Guillot, Michelle

    2011-01-01

    The External Tank forms the structural backbone of the Space Shuttle in the launch configuration. Because the tank flies to orbital velocity with the Space Shuttle Orbiter, minimization of weight is mandatory, to maximize payload performance. Choice of lightweight materials both for structure and thermal conditioning was necessary. The tank is large, and unique manufacturing facilities, tooling, handling, and transportation operations were required. Weld processes and tooling evolved with the design as it matured through several block changes, to reduce weight. Non Destructive Evaluation methods were used to assure integrity of welds and thermal protection system materials. The aluminum-lithium alloy was used near the end of the program and weld processes and weld repair techniques had to be refined. Development and implementation of friction stir welding was a substantial technology development incorporated during the Program. Automated thermal protection system application processes were developed for the majority of the tank surface. Material obsolescence was an issue throughout the 40 year program. The final configuration and tank weight enabled international space station assembly in a high inclination orbit allowing international cooperation with the Russian Federal Space Agency. Numerous process controls were implemented to assure product quality, and innovative proof testing was accomplished prior to delivery. Process controls were implemented to assure cleanliness in the production environment, to control contaminants, and to preclude corrosion. Each tank was accepted via rigorous inspections, including non-destructive evaluation techniques, proof testing, and all systems testing. In the post STS-107 era, the project focused on ascent debris risk reduction. This was accomplished via stringent process controls, post flight assessment using substantially improved imagery, and selective redesigns. These efforts were supported with a number of test programs to

  17. Feed tank transfer requirements

    SciTech Connect

    Freeman-Pollard, J.R.

    1998-09-16

    This document presents a definition of tank turnover. Also, DOE and PC responsibilities; TWRS DST permitting requirements; TWRS Authorization Basis (AB) requirements; TWRS AP Tank Farm operational requirements; unreviewed safety question (USQ) requirements are presented for two cases (i.e., tank modifications occurring before tank turnover and tank modification occurring after tank turnover). Finally, records and reporting requirements, and documentation which will require revision in support of transferring a DST in AP Tank Farm to a privatization contractor are presented.

  18. Tank Insulation

    NASA Technical Reports Server (NTRS)

    1979-01-01

    For NASA's Apollo program, McDonnell Douglas Astronautics Company, Huntington Beach, California, developed and built the S-IVB, uppermost stage of the three-stage Saturn V moonbooster. An important part of the development task was fabrication of a tank to contain liquid hydrogen fuel for the stage's rocket engine. The liquid hydrogen had to be contained at the supercold temperature of 423 degrees below zero Fahrenheit. The tank had to be perfectly insulated to keep engine or solar heat from reaching the fuel; if the hydrogen were permitted to warm up, it would have boiled off, or converted to gaseous form, reducing the amount of fuel available to the engine. McDonnell Douglas' answer was a supereffective insulation called 3D, which consisted of a one-inch thickness of polyurethane foam reinforced in three dimensions with fiberglass threads. Over a 13-year development and construction period, the company built 30 tanks and never experienced a failure. Now, after years of additional development, an advanced version of 3D is finding application as part of a containment system for transporting Liquefied Natural Gas (LNG) by ship.

  19. The carbonation of autoclaved aerated concrete

    SciTech Connect

    Hanecka, K.; Koronthalyova, O.; Matiasovsky, P.

    1997-04-01

    During the long-term investigation of the physical properties of autoclaved aerated concrete (AAC) in the indoor environment with changing relative humidity and temperature the significant increase of the AAC density was found. It was proved that the increase of the density was a consequence of carbonation process. For the investigated types of the AAC the ultimate increase of density was proportional to initial dry density of the AAC. It was found as well that relative volumes of the micropores (with radius from 3.5 nm to 7,500 nm) of the investigated types of the AAC are proportional to their dry densities. The simulation of the time courses of density increase due to carbonation based on solution of modified diffusion equation was done. In spite of using simplifications (constant value of CO{sub 2} diffusion coefficient, neglecting the relative humidity changes), the calculated time courses coincided sufficiently with the measured ones.

  20. Stirring effect on kaolinite dissolution rate

    NASA Astrophysics Data System (ADS)

    Metz, Volker; Ganor, Jiwchar

    2001-10-01

    Experiments were carried out measuring kaolinite dissolution rates using stirred and nonstirred flow-through reactors at pHs 2 to 4 and temperatures of 25°C, 50°C, and 70°C. The results show an increase of kaolinite dissolution rate with increasing stirring speed. The stirring effect is reversible, i.e., as the stirring slows down the dissolution rate decreases. The effect of stirring speed on kaolinite dissolution rate is higher at 25°C than at 50°C and 70°C and at pH 4 than at pHs 2 and 3. It is suggested that fine kaolinite particles are formed as a result of stirring-induced spalling or abrasion of kaolinite. These very fine particles have an increased ratio of reactive surface area to specific surface area, which results in enhancement of kaolinite dissolution rate. A balance between production and dissolution of the fine particles explains both the reversibility and the temperature and pH dependence of the stirring effect. Since the stirring effect on kaolinite dissolution rate varies with temperature and pH, measurement of kinetic parameters such as activation energy may be influenced by stirring. Therefore, standard use of nonagitated reaction vessels for kinetic experiments of mineral dissolution and precipitation is recommended, at least for slow reactions that are surface controlled.

  1. Effect of aeration rate on composting of penicillin mycelial dreg.

    PubMed

    Chen, Zhiqiang; Zhang, Shihua; Wen, Qinxue; Zheng, Jun

    2015-11-01

    Pilot scale experiments with forced aeration were conducted to estimate effects of aeration rates on the performance of composting penicillin mycelial dreg using sewage sludge as inoculation. Three aeration rates of 0.15, 0.50 and 0.90L/(min·kg) organic matter (OM) were examined. The principal physicochemical parameters were monitored during the 32day composting period. Results showed that the higher aeration rate of 0.90L/(min·kg) did not corresponded to a longer thermophilic duration and higher rates of OM degradation; but the lower aeration rate of 0.15L/(min·kg) did induce an accumulation of NH4(+)-N contents due to the inhibition of nitrification. On the other hand, aeration rate has little effect on degradation of penicillin. The results show that the longest phase of thermophilic temperatures≥55°C, the maximum NO3(-)-N content and seed germination, and the minimum C/N ratio were obtained with 0.50L/(min·kg) OM. Therefore, aeration rates of 0.50L/(min·kg) OM can be recommended for composting penicillin mycelial dreg.

  2. 49 CFR 172.331 - Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. 172.331 Section 172.331 Transportation Other Regulations... packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. (a) Each...

  3. 49 CFR 172.331 - Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. 172.331 Section 172.331 Transportation Other Regulations... packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. (a) Each...

  4. 49 CFR 172.331 - Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. 172.331 Section 172.331 Transportation Other Regulations... packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. (a) Each...

  5. 49 CFR 172.331 - Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. 172.331 Section 172.331 Transportation Other Regulations... packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. (a) Each...

  6. 49 CFR 172.331 - Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Bulk packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. 172.331 Section 172.331 Transportation Other Regulations... packagings other than portable tanks, cargo tanks, tank cars and multi-unit tank car tanks. (a) Each...

  7. Analysis of up-flow aerated biological activated carbon filter technology in drinking water treatment.

    PubMed

    Lu, Shaoming; Liu, Jincui; Li, Shaowen; Biney, Elizabeth

    2013-01-01

    Problems have been found in the traditional post-positioned down-flow biological activated carbon filter (DBACF), such as microorganism leakage and low biodegradability. A pilot test was carried out to place a BACF between the sediment tank and the sand filter; a new technology of dual media up-flow aerated biological activated carbon filter (UBACF) was developed. Results showed that in terms of the new process, the up-flow mode was better than the down-flow. Compared with the DBACF, the problem of microorganism leakage could be well resolved with the UBACF process by adding disinfectant before the sand filtration, and a similar adsorption effect could be obtained. For the tested raw water, the COD(Mn) and NH3-N removal rate was 54.6% and 85.0%, respectively, similar to the waterworks with the DBACF process. The UBACF greatly enhanced oxygen supply capability and mass transfer rate via aeration, and the NH3-N removal ability was significantly improved from 1.5 mg/L to more than 3 mg/L. Influent to the UBACF with higher turbidity could be coped with through the primary filtration of the ceramisite layer combined with fluid-bed technology, which gave the carbon bed a low-turbidity environment of less than 1.0 NTU. The backwashing parameters and carbon abrasion rate of the two processes were almost the same.

  8. Optimisation of aeration for activated sludge treatment with simultaneous nitrification denitrification.

    PubMed

    Thauré, David; Lemoine, Cyrille; Daniel, Olivier; Moatamri, Nader; Chabrol, Julien

    2008-01-01

    Following a promising study at pilot scale a new aeration control law has been implemented at a full scale wastewater treatment plant displaying a conventional activated sludge process. The new control law is based on the direct measurements of ammonium and nitrate concentration in the biological tank by ion selective electrodes. This control law features a cascade of two Predictive Function Controls and calculates an optimal air flow rate to be provided to the biomass through fine bubble diffusers. The results obtained at the full scale plant confirmed the high performance of this control strategy allowing to substantially reduce the amount of diffused air while providing an easy means to manage the effluent quality to the plant operator.

  9. Pulsed ultrasonic stir welding method

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    A method of performing ultrasonic stir welding uses a welding head assembly to include a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. In the method, the rod is rotated about its longitudinal axis during a welding operation. During the welding operation, a series of on-off ultrasonic pulses are applied to the rod such that they propagate parallel to the rod's longitudinal axis. At least a pulse rate associated with the on-off ultrasonic pulses is controlled.

  10. Retractable Pin Tools for the Friction Stir Welding Process

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Two companies have successfully commercialized a specialized welding tool developed at the Marshall Space Flight Center (MSFC). Friction stir welding uses the high rotational speed of a tool and the resulting frictional heat created from contact to crush, 'stir' together, and forge a bond between two metal alloys. It has had a major drawback, reliance on a single-piece pin tool. The pin is slowly plunged into the joint between two materials to be welded and rotated as high speed. At the end of the weld, the single-piece pin tool is retracted and leaves a 'keyhole,' something which is unacceptable when welding cylindrical objects such as drums, pipes and storage tanks. Another drawback is the requirement for different-length pin tools when welding materials of varying thickness. An engineer at the MSFC helped design an automatic retractable pin tool that uses a computer-controlled motor to automatically retract the pin into the shoulder of the tool at the end of the weld, preventing keyholes. This design allows the pin angle and length to be adjusted for changes in material thickness and results in a smooth hole closure at the end of the weld. Benefits of friction stir welding, using the MSFC retractable pin tool technology, include the following: The ability to weld a wide range of alloys, including previously unweldable and composite materials; provision of twice the fatigue resistance of fusion welds and no keyholes; minimization of material distortion; no creation of hazards such as welding fumes, radiation, high voltage, liquid metals, or arcing; automatic retraction of the pin at the end of the weld; and maintaining full penetration of the pin.

  11. Friction Stir Weld Restart+Reweld Repair Allowables

    NASA Technical Reports Server (NTRS)

    Clifton, Andrew

    2008-01-01

    A friction stir weld (FSW) repair method has been developed and successfully implemented on Al 2195 plate material for the Space Shuttle External Fuel Tank (ET). The method includes restarting the friction stir weld in the termination hole of the original weld followed by two reweld passes. Room temperature and cryogenic temperature mechanical properties exceeded minimum FSW design strength and compared well with the development data. Simulated service test results also compared closely to historical data for initial FSW, confirming no change to the critical flaw size or inspection requirements for the repaired weld. Testing of VPPA fusion/FSW intersection weld specimens exhibited acceptable strength and exceeded the minimum design value. Porosity, when present at the intersection was on the root side toe of the fusion weld, the "worst case" being 0.7 inch long. While such porosity may be removed by sanding, this "worst case" porosity condition was tested "as is" and demonstrated that porosity did not negatively affect the strength of the intersection weld. Large, 15-inch "wide panels" FSW repair welds were tested to demonstrate strength and evaluate residual stresses using photo stress analysis. All results exceeded design minimums, and photo stress analysis showed no significant stress gradients due to the presence of the restart and multi-pass FSW repair weld.

  12. Investigation of Machine Design for Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Romine, Peter L.

    1996-01-01

    The process of joining two pieces of metal together has not significantly changed over the last few decades. The basic idea used is to bring the pieces together and apply enough heat to melt the metal at the interface. The molten metal mixes and after cooling forms a strong joint. This process is called the fusion process. The most significant difference between the many fusion processes is how the heat is generated and applied. The Welding Institute (TWI), in Great Britain, has recently patented an innovative application of mechanical friction. TWI designed a tool and process called Friction Stir Welding (FSW) that uses friction to heat the metal to within a few hundred degrees Fahrenheit of melting, just to the point of being plastic-like. The tool then stirs the plasticized metal together forming a joint that has been shown to be as good or better than an equivalent fusion joint. The FSW process is well suited for the joining of the aluminum alloys used in the aerospace industry. The relatively low melting point of aluminum eliminates the requirements for exotic materials for pin tool design. The FSW process has been successfully used to join alloys such as 7075 which were before considered "unweldable", and aluminum-lithium 2195 which exhibits many problems when fusion welded. The objective this summer was to investigate the design of a FSW system that could take this process from the laboratory to the manufacturing floor. In particular, it was the goal of my NASA colleague to develop a concept for applying the FSW process to the manufacturing of aluminum cryogenic oxygen and hydrogen tanks, of the sort used to make the Shuttle External Tank.

  13. Wiping Metal Transfer in Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Nunes, Arthur C., Jr.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Much evidence suggests that as the friction stir pin-tool moves along a weld seam the displacement of metal takes place by a wiping action at the surface of a plug of metal that rotates with the tool. The wiping model is explained and some consequences for the friction stir welding process are drawn.

  14. Gimbaled-shoulder friction stir welding tool

    NASA Technical Reports Server (NTRS)

    Carter, Robert W. (Inventor); Lawless, Kirby G. (Inventor)

    2010-01-01

    A gimbaled-shoulder friction stir welding tool includes a pin and first and second annular shoulders coupled to the pin. At least one of the annular shoulders is coupled to the pin for gimbaled motion with respect thereto as the tool is rotated by a friction stir welding apparatus.

  15. INVESTIGATIONS INTO BIOFOULING PHENOMENA IN FINE PORE AERATION DEVICES

    EPA Science Inventory

    Microbiologically-based procedures were used to describe biofouling phenomena on fine pore aeration devices and to determine whether biofilm characteristics could be related to diffuser process performance parameters. Fine pore diffusers were obtained from five municipal wastewa...

  16. Calibration of a passive sampler based on stir bar sorptive extraction for the monitoring of hydrophobic organic pollutants in water.

    PubMed

    Vrana, Branislav; Komancová, Lucie; Sobotka, Jaromír

    2016-05-15

    A passive sampler based on stir bars coated with polydimethylsiloxane (PDMS) was calibrated for the measurement of time-weighted average concentrations of hydrophobic micropollutants, including polycyclic aromatic hydrocarbons, polychlorinated biphenyls and organochlorine pesticides, in water. Stir bar/water partition coefficients were measured by equilibrating bars with sheets made of silicone rubber material for which partition coefficients had been reported previously. Kinetic parameters characterising the exchange of analytes between stir bars and water were determined under controlled exposure conditions using a passive dosing system. The dosing system consisted of silicone rubber sheets with a large surface area, spiked with analytes. During stir bar sampler exposure, analytes partitioned from dosing sheets to water in the exposure tank and maintained constant exposure concentrations. Reversible and isotropic exchange kinetics of analytes between sampler and water was confirmed by measuring the release of a range of performance reference compounds (PRCs) from stir bars. Application of a two-resistance model confirmed that, except for hexachlorocyclohexane isomers, uptake of the test compounds under the experimental conditions was controlled by diffusion in the water boundary layer. This permits the application of PRCs for in situ calibration of uptake kinetics of test compounds to stir bars.

  17. AX Tank Farm tank removal study

    SciTech Connect

    SKELLY, W.A.

    1999-02-24

    This report examines the feasibility of remediating ancillary equipment associated with the 241-AX Tank Farm at the Hanford Site. Ancillary equipment includes surface structures and equipment, process waste piping, ventilation components, wells, and pits, boxes, sumps, and tanks used to make waste transfers to/from the AX tanks and adjoining tank farms. Two remedial alternatives are considered: (1) excavation and removal of all ancillary equipment items, and (2) in-situ stabilization by grout filling, the 241-AX Tank Farm is being employed as a strawman in engineering studies evaluating clean and landfill closure options for Hanford single-shell tanks. This is one of several reports being prepared for use by the Hanford Tanks Initiative Project to explore potential closure options and to develop retrieval performance evaluation criteria for tank farms.

  18. Stirring properties of vortex rings

    NASA Astrophysics Data System (ADS)

    Auerbach, David

    1991-05-01

    Ring vortex evolution, from the initial roll-up phase through to the final turbulent phase, was experimentally studied to see the dependence of its stirring properties on both the initial (accelerating, constant, decelerating, slow, fast) piston motion as well as on the boundary (tube/hole geometry) conditions. Stirring between fluid initially upstream and that initially downstream of the nozzle plane is done more by convective entrainment at the beginning (roll-up and contraction phases), by diffusive entrainment during the laminar and wavy phases, and by mixed entrainment and ejection during the transition to turbulence and the turbulent phase itself. During vortex roll-up, it was found that tubes eject shorter streaklines than do holes, and that there is less Re dependence for this for tubes than for holes. During the contraction phase, entrainment ends, save for minimal entrainment due to axial inflow into the ring from along the cores of Goertler-type vortices. Generally, the rate of fluid ejected is largest during the transition from the wavy to the turbulent state. As far as the stability of the vortices is concerned, rings generated at holes are less stable than those generated at tubes. During the final turbulent phase, rings not only entrain fluid but eject it periodically into the wake: Between two and four hairpin vortices are generated and laid off in the wake during each ejection. The frequency at which such ejections takes place scales as a Strouhal number that takes on values of between 2 and 4.

  19. Tank 241-U-203: Tank Characterization Plan

    SciTech Connect

    Sathyanarayana, P.

    1995-03-27

    The revised Federal Facility Agreement and Consent Order states that a tank characterization plan will be developed for each double-shell tank and single-shell tank using the data quality objective process. The plans are intended to allow users and regulators to ensure their needs will be met and resources are devoted to gaining only necessary information. This document satisfies that requirement for Tank 241-U-203 sampling activities.

  20. Enhancement of Nitrogen Removal in an Intermittent Aeration Membrane Bioreactor

    NASA Astrophysics Data System (ADS)

    He, Xiaojuan; Wisniewski, Christelle; Li, Xudong; Zhou, Qi

    2010-11-01

    An intermittent aerated membrane bioreactor was applied in laboratory scale to treat synthetic household wastewater. The system organic load and nitrogen load were 0.34 kgCODṡm-3ṡd-1 and 0.06 kgTNṡm-3ṡd-1, respectively. The hydraulic residence time was equal to 12 h and very long sludge residence times were imposed. Intermittent aeration, with anoxic-aerobic cycle of 30/60 minutes, was employed in the system. The results showed that 100% SS and >90% COD could be removed. The average removal efficiency of NH4-N and TN was 99.7% and 80%, respectively. A linear relationship between the fouling rate and the MLSS, MLVSS concentration was founded. The denitrification seemed to be the rate-limiting step for nitrogen removal. To enhance denitrification, the following strategies could be considered: 1) to select suitable aeration/non-aeration cycle, 2) to control the aeration intensity, 3) to feed the system at the beginning of non-aeration period, 4) to maintain high MLSS concentration.

  1. 49 CFR 172.330 - Tank cars and multi-unit tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Tank cars and multi-unit tank car tanks. 172.330..., TRAINING REQUIREMENTS, AND SECURITY PLANS Marking § 172.330 Tank cars and multi-unit tank car tanks. (a... material— (1) In a tank car unless the following conditions are met: (i) The tank car must be marked...

  2. Thermal inertia properties of autoclaved aerated concrete

    SciTech Connect

    Ropelewski, L.; Neufeld, R.D.

    1999-08-01

    Autoclaved aerated concrete (AAC) is a lightweight, porous concrete with advanced thermal properties. AAC is unique among construction materials in combining excellent thermal resistance and thermal inertia. Generally, low-density construction materials do not provide good thermal inertia, while heavier ones commonly have poor thermal resistance. Five different 10.2 cm (4 in.) AAC samples made from US electric utility fly ash as the silica source, along with three 10.2 cm (4 in.) conventional building material specimens, were tested for thermal inertia properties. Three primary issues addressed by these experiments were: (1) to develop and compare AAC thermal inertia to conventional building materials; (2) to document differences in thermal inertia characteristics of the AAC blocks produced by the various utilities; and (3) to determine if a periodic heat flow model using the thermal inertia approach adequately predicts the observed thermal inertia parameters of a material. A theoretical periodic heat flow model in the literature for thermal inertia did an adequate job of predicting the observed thermal inertia parameters for the AAC and conventional construction samples.

  3. The influence of pH and aeration rate on the fermentation of D-xylose by Candida shehatae.

    PubMed

    Sánchez, S; Bravo, V; Castro, E; Moya, A J; Camacho, F

    1997-10-01

    The effects of the initial pH and air supply on the production of ethanol from D-xylose using the yeast Candida shehatae in a batch reactor were investigated. The initial pH was altered within the range of 2.5-6.5 and the specific aeration rate from 0.0-0.3 vv-1 min-1. The results showed that the most favorable initial pH for ethanol production was 4.5 and aeration via the stirring vortex of the bioreactor was sufficient. Under these conditions, the maximum specific growth rate (mu(m)) was 0.329 h-1; biomass production rate (b), 0.024 kg m-3 h-1; overall biomass yield (YGx/s), 0.036 kg kg-1; the specific uptake rate of D-xylose (qs), 2.0 kg kg-1 h-1; and the specific ethanol production rate (qE), 0.72 kg kg-1 h-1 (both at 20 h culture time). The average xylitol yield (Yxy/s) was 0.078 kg kg-1 and the overall ethanol yield (YGE/s), 0.41 kg kg-1. Both qs and qE diminished once the exponential growth phase was over.

  4. AX Tank Farm tank removal study

    SciTech Connect

    SKELLY, W.A.

    1998-10-14

    This report considers the feasibility of exposing, demolishing, and removing underground storage tanks from the 241-AX Tank Farm at the Hanford Site. For the study, it was assumed that the tanks would each contain 360 ft{sup 3} of residual waste (corresponding to the one percent residual Inventory target cited in the Tri-Party Agreement) at the time of demolition. The 241-AX Tank Farm is being employed as a ''strawman'' in engineering studies evaluating clean and landfill closure options for Hanford single-shell tank farms. The report is one of several reports being prepared for use by the Hanford Tanks Initiative Project to explore potential closure options and to develop retrieval performance evaluation criteria for tank farms.

  5. Macrostructure of Friction Stir Welds

    NASA Technical Reports Server (NTRS)

    Aloor, S.; Nowak, B.; Vargas, R.; McClure, J. C.; Murr, L. E.; Nunes, A. C.; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    This paper will discuss two of the well know large scale features of friction stir welds: the "onion rings" seen in transverse sections, and the striations on the surface of the work piece. It will be shown that the surface features (sometimes called "tool marks") are the result of irregularities on the rotating shoulder of the pin tool and disappear when the shoulder is polished. The "onion ring" structure seen in transverse cross sections is formed by parts of the "carousel", the zone of material adjacent to and rotating with the pin tool, that are shed off in each rotation. The relation between the carousel and the "ring vortex", a rotational flow extending both in and out of the carousel and resembling a smoke-ring with the hole centered on the pin tool, will be discussed.

  6. Friction Stir Welding and Processing

    SciTech Connect

    Hovanski, Yuri; Carsley, John; Clarke, Kester D.; Krajewski, Paul E.

    2015-05-01

    With nearly twenty years of international research and collaboration in friction stir welding (FSW) and processing industrial applications have spread into nearly every feasible market. Currently applications exist in aerospace, railway, automotive, personal computers, technology, marine, cutlery, construction, as well as several other markets. Implementation of FSW has demonstrated diverse opportunities ranging from enabling new materials to reducing the production costs of current welding technologies by enabling condensed packaging solutions for traditional fabrication and assembly. TMS has sponsored focused instruction and communication in this technology area for more than fifteen years, with leadership from the Shaping and Forming Committee, which organizes a biannual symposium each odd year at the annual meeting. A focused publication produced from each of these symposia now comprises eight volumes detailing the primary research and development activities in this area over the last two decades. The articles assembled herein focus on both recent developments and technology reviews of several key markets from international experts in this area.

  7. Characterization of Odorant Compounds from Mechanical Aerated Pile Composting and Static Aerated Pile Composting

    PubMed Central

    Kumari, Priyanka; Lee, Joonhee; Choi, Hong-Lim

    2016-01-01

    We studied airborne contaminants (airborne particulates and odorous compounds) emitted from compost facilities in South Korea. There are primarily two different types of composting systems operating in Korean farms, namely mechanical aerated pile composting (MAPC) and aerated static pile composting (SAPC). In this study, we analyzed various particulate matters (PM10, PM7, PM2.5, PM1, and total suspended particles), volatile organic compounds and ammonia, and correlated these airborne contaminants with microclimatic parameters, i.e., temperature and relative humidity. Most of the analyzed airborne particulates (PM7, PM2.5, and PM1) were detected in high concentration at SAPC facilities compered to MAPC; however these differences were statistically non-significant. Similarly, most of the odorants did not vary significantly between MAPC and SAPC facilities, except for dimethyl sulfide (DMS) and skatole. DMS concentrations were significantly higher in MAPC facilities, whereas skatole concentrations were significantly higher in SAPC facilities. The microclimate variables also did not vary significantly between MAPC and SAPC facilities, and did not correlate significantly with most of the airborne particles and odorous compounds, suggesting that microclimate variables did not influence their emission from compost facilities. These findings provide insight into the airborne contaminants that are emitted from compost facilities and the two different types of composting agitation systems. PMID:26949962

  8. Integrated in-line coagulation-aerated ultrafiltration for drinking-water production: A case study from laboratory to pilot plant.

    PubMed

    Rojas-Serrano, Fátima; Pérez, Jorge I; Gómez, Miguel A

    2015-01-01

    A pilot-scale study was made for drinking-water production from low-quality influents with in-line coagulation as pre-treatment of aerated ultrafiltration. Optimum flocculation parameters were previously determined in the laboratory, searching for large and strong flocs that could resist aeration without increasing the membrane fouling. Nevertheless, the comparison of the jar tests and the pilot-scale results showed that the former could help pre-dimensioning the flocculation facilities but could not precisely reproduce the behavior of the flocs in the membrane tank. The optimum coagulant dosage enabled the highest dissolved organic carbon (DOC) removal without affecting membrane fouling. Additionally, as opposed to the jar-test results, long retention times led to the lowest fouling rates while the velocity gradient affected neither the effluent quality nor the membrane fouling. These findings suggested that the influence of the flocculation parameters was masked by aeration inside the membrane tank but, even so, 43% and 82% DOC and UVA254 removals, respectively, were reached. Furthermore, the growth of the total membrane resistance with time was logarithmic instead of linear, confirming the suitability of the pre-treatment for low-quality influents.

  9. [Research of controlling condition for aeration stabilization pond dealing with sanitary waste of countryside].

    PubMed

    Li, Huai-Zheng; Yao, Shu-Jun; Xu, Zu-Xin; Chen, Wei-Bing

    2012-10-01

    According to research of some problems, such as the hydraulic detention time that aeration stabilization pond deals with sanitary waste of countryside, dissolved oxygen in pond during the process of aeration, the concentration distribution of sludge and different aeration periods affecting on the treatment efficiency, we can acquire good treatment efficiency and energy consumption of economy. The results indicate that under the aeration stabilization pond of this experiment, 4 d is the best hydraulic detention time with this aeration stabilization pond. Time of the discontinuous running aeration should be greater than 15 min. The concentration distribution of sludge can reach equilibrium at each point of aeration stabilization pond between 2 min and 10 min. The best aeration period of dislodging the pollutant is 0.5 h aeration/1.0 h cut-off.

  10. [Effects of nitrogen source and aeration mode on algae growth in freshwater].

    PubMed

    Liu, Chun-Guang; Jin, Xiang-Can; Sun, Ling; Sun, Hong-Wen; Zhu, Lin; Yu, Yang; Dai, Shu-Gui; Zhuang, Yuan-Yi

    2006-01-01

    Aquarium microcosms were used to study the effects of nitrogen source and aeration mode on the growth and species changes of algae in freshwater. Nitrate nitrogen(NO3(-) -N) and ammonia nitrogen(NH4(+) -N) were used as nitrogen sources. For each nitrogen source, four modes of aeration were selected, including control, continuous aeration, aeration during the day, and aeration at night. In the early stage of the experiment, algae in the NH4(+) -N treatment experiment grew well. In the later stage, algae in the NO3(-) -N treatment experiment grew better. For different aeration modes, continuous aeration show varied effects on algae growth in the two nitrogen source treatments. Day-only aeration had little effect on algae growth. Night-only aeration inhibited algae growth considerably. In NH(+) -N treatments, cyanophyta became dominant species easily. In contrast, chlorophyta dominated in NO3(-) -N treatments.

  11. HANFORD TANK CLEANUP UPDATE

    SciTech Connect

    BERRIOCHOA MV

    2011-04-07

    Access to Hanford's single-shell radioactive waste storage tank C-107 was significantly improved when workers completed the cut of a 55-inch diameter hole in the top of the tank. The core and its associated cutting equipment were removed from the tank and encased in a plastic sleeve to prevent any potential spread of contamination. The larger tank opening allows use of a new more efficient robotic arm to complete tank retrieval.

  12. Process Model for Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Adams, Glynn

    1996-01-01

    Friction stir welding (FSW) is a relatively new process being applied for joining of metal alloys. The process was initially developed by The Welding Institute (TWI) in Cambridge, UK. The FSW process is being investigated at NASA/MSEC as a repair/initial weld procedure for fabrication of the super-light-weight aluminum-lithium shuttle external tank. The FSW investigations at MSFC were conducted on a horizontal mill to produce butt welds of flat plate material. The weldment plates are butted together and fixed to a backing plate on the mill bed. A pin tool is placed into the tool holder of the mill spindle and rotated at approximately 400 rpm. The pin tool is then plunged into the plates such that the center of the probe lies at, one end of the line of contact, between the plates and the shoulder of the pin tool penetrates the top surface of the weldment. The weld is produced by traversing the tool along the line of contact between the plates. A lead angle allows the leading edge of the shoulder to remain above the top surface of the plate. The work presented here is the first attempt at modeling a complex phenomenon. The mechanical aspects of conducting the weld process are easily defined and the process itself is controlled by relatively few input parameters. However, in the region of the weld, plasticizing and forging of the parent material occurs. These are difficult processes to model. The model presented here addresses only variations in the radial dimension outward from the pin tool axis. Examinations of the grain structure of the weld reveal that a considerable amount of material deformation also occurs in the direction parallel to the pin tool axis of rotation, through the material thickness. In addition, measurements of the axial load on the pin tool demonstrate that the forging affect of the pin tool shoulder is an important process phenomenon. Therefore, the model needs to be expanded to account for the deformations through the material thickness and the

  13. Spray Nozzles, Pressures, Additives and Stirring Time on Viability and Pathogenicity of Entomopathogenic Nematodes (Nematoda: Rhabditida) for Greenhouses

    PubMed Central

    Moreira, Grazielle Furtado; Batista, Elder Simões de Paula; Campos, Henrique Borges Neves; Lemos, Raphael Emilio; Ferreira, Marcelo da Costa

    2013-01-01

    The objective of this study was to evaluate different strategies for the application of entomopathogenic nematodes (EPN). Three different models of spray nozzles with air induction (AI 11003, TTI 11003 and AD-IA 11004), three spray pressures (207, 413 and 720 kPa), four different additives for tank mixtures (cane molasses, mineral oil, vegetable oil and glycerin) and the influence of tank mixture stirring time were all evaluated for their effect on EPN (Steinernema feltiae) viability and pathogenicity. The different nozzles, at pressures of up to 620 kPa, were found to be compatible with S. feltiae. Vegetable oil, mineral oil and molasses were found to be compatible adjuvants for S. feltiae, and stirring in a motorized backpack sprayer for 30 minutes did not impact the viability or pathogenicity of this nematode. Appropriate techniques for the application of nematodes with backpack sprayers are discussed. PMID:23755280

  14. Spray nozzles, pressures, additives and stirring time on viability and pathogenicity of entomopathogenic nematodes (nematoda: rhabditida) for greenhouses.

    PubMed

    Moreira, Grazielle Furtado; Batista, Elder Simões de Paula; Campos, Henrique Borges Neves; Lemos, Raphael Emilio; Ferreira, Marcelo da Costa

    2013-01-01

    The objective of this study was to evaluate different strategies for the application of entomopathogenic nematodes (EPN). Three different models of spray nozzles with air induction (AI 11003, TTI 11003 and AD-IA 11004), three spray pressures (207, 413 and 720 kPa), four different additives for tank mixtures (cane molasses, mineral oil, vegetable oil and glycerin) and the influence of tank mixture stirring time were all evaluated for their effect on EPN (Steinernema feltiae) viability and pathogenicity. The different nozzles, at pressures of up to 620 kPa, were found to be compatible with S. feltiae. Vegetable oil, mineral oil and molasses were found to be compatible adjuvants for S. feltiae, and stirring in a motorized backpack sprayer for 30 minutes did not impact the viability or pathogenicity of this nematode. Appropriate techniques for the application of nematodes with backpack sprayers are discussed.

  15. Tank 241-C-103 tank characterization plan

    SciTech Connect

    Schreiber, R.D.

    1994-10-06

    The data quality objective (DQO) process was chosen as a tool to be used to identify the sampling analytical needs for the resolution of safety issues. A Tank Characterization Plant (TCP) will be developed for each double shell tank (DST) and single-shell tank (SST) using the DQO process. There are four Watch list tank classifications (ferrocyanide, organic salts, hydrogen/flammable gas, and high heat load). These classifications cover the six safety issues related to public and worker health that have been associated with the Hanford Site underground storage tanks. These safety issues are as follows: ferrocyanide, flammable gas, organic, criticality, high heat, and vapor safety issues. Tank C-103 is one of the twenty tanks currently on the Organic Salts Watch List. This TCP will identify characterization objectives pertaining to sample collection, hot cell sample isolation, and laboratory analytical evaluation and reporting requirements in accordance with the appropriate DQO documents. In addition, the current contents and status of the tank are projected from historical information. The relevant safety issues that are of concern for tanks on the Organic Salts Watch List are: the potential for an exothermic reaction occurring from the flammable mixture of organic materials and nitrate/nitrite salts that could result in a release of radioactive material and the possibility that other safety issues may exist for the tank.

  16. Influence of aeration rate on nitrogen dynamics during composting.

    PubMed

    de Guardia, A; Petiot, C; Rogeau, D; Druilhe, C

    2008-01-01

    The paper aimed to study the influence of aeration rate on nitrogen dynamics during composting of wastewater sludge with wood chips. Wastewater sludge was sampled at a pig slaughterhouse 24h before each composting experiment, and mixtures were made at the same mass ratio. Six composting experiments were performed in a lab reactor (300 L) under forced aeration. Aeration flow was constant throughout the experiment and aeration rates applied ranged between 1.69 and 16.63 L/h/kg DM of mixture. Material temperature and oxygen consumption were monitored continuously. Nitrogen losses in leachates as organic and total ammoniacal nitrogen, nitrite and nitrate, and losses in exhaust gases as ammonia were measured daily. Concentrations of total carbon and nitrogen i.e., organic nitrogen, total ammoniacal nitrogen, and nitrite and nitrate were measured in the initial substrates and in the composted materials. The results showed that organic nitrogen, which was released as NH4+/NH3 by ammonification, was closely correlated to the ratio of carbon removed from the material to TC/N(org) of the initial substrates. The increase of aeration was responsible for the increase in ammonia emissions and for the decrease in nitrogen losses through leaching. At high aeration rates, losses of nitrogen in leachates and as ammonia in exhaust gases accounted for 90-99% of the nitrogen removed from the material. At low aeration rates, those accounted for 47-85% of the nitrogen removed from the material. The highest concentrations of total ammoniacal nitrogen in composts occurred at the lowest aeration rate. Due to the correlation of ammonification with biodegradation and to the measurements of losses in leachates and in exhaust gases, the pool NH4+/NH3 in the composting material was calculated as a function of time. The nitrification rate was found to be proportional to the mean content of NH4+/NH3 in the material, i.e., initial NH4+/NH3 plus NH4+/NH3 released by ammonification minus losses in

  17. Evaluation of an integrated continuous stirred microbial electrochemical reactor: Wastewater treatment, energy recovery and microbial community.

    PubMed

    Wang, Haiman; Qu, Youpeng; Li, Da; Zhou, Xiangtong; Feng, Yujie

    2015-11-01

    A continuous stirred microbial electrochemical reactor (CSMER) was developed by integrating anaerobic digestion (AD) and microbial electrochemical system (MES). The system was capable of treating high strength artificial wastewater and simultaneously recovering electric and methane energy. Maximum power density of 583±9, 562±7, 533±10 and 572±6 mW m(-2) were obtained by each cell in a four-independent circuit mode operation at an OLR of 12 kg COD m(-3) d(-1). COD removal and energy recovery efficiency were 87.1% and 32.1%, which were 1.6 and 2.5 times higher than that of a continuous stirred tank reactor (CSTR). Larger amount of Deltaproteobacteria (5.3%) and hydrogenotrophic methanogens (47%) can account for the better performance of CSMER, since syntrophic associations among them provided more degradation pathways compared to the CSTR. Results demonstrate the CSMER holds great promise for efficient wastewater treatment and energy recovery.

  18. Numerical simulation of landfill aeration using computational fluid dynamics.

    PubMed

    Fytanidis, Dimitrios K; Voudrias, Evangelos A

    2014-04-01

    The present study is an application of Computational Fluid Dynamics (CFD) to the numerical simulation of landfill aeration systems. Specifically, the CFD algorithms provided by the commercial solver ANSYS Fluent 14.0, combined with an in-house source code developed to modify the main solver, were used. The unsaturated multiphase flow of air and liquid phases and the biochemical processes for aerobic biodegradation of the organic fraction of municipal solid waste were simulated taking into consideration their temporal and spatial evolution, as well as complex effects, such as oxygen mass transfer across phases, unsaturated flow effects (capillary suction and unsaturated hydraulic conductivity), temperature variations due to biochemical processes and environmental correction factors for the applied kinetics (Monod and 1st order kinetics). The developed model results were compared with literature experimental data. Also, pilot scale simulations and sensitivity analysis were implemented. Moreover, simulation results of a hypothetical single aeration well were shown, while its zone of influence was estimated using both the pressure and oxygen distribution. Finally, a case study was simulated for a hypothetical landfill aeration system. Both a static (steadily positive or negative relative pressure with time) and a hybrid (following a square wave pattern of positive and negative values of relative pressure with time) scenarios for the aeration wells were examined. The results showed that the present model is capable of simulating landfill aeration and the obtained results were in good agreement with corresponding previous experimental and numerical investigations.

  19. Sludge reduction using aquatic worms under different aeration regimes.

    PubMed

    Cai, Lu; Gao, Ding; Wang, Kan; Liu, Hong-Tao; Wan, Xiao-Ming

    2017-03-01

    Adding aquatic worms to a wastewater treatment system can reduce sludge production through predation. The aeration level is crucial for success. To evaluate aeration impacts on sludge reduction and determine an optimal aeration regime, this study investigated the processes of in-situ sludge reduction, using aquatic worms exposed to different aeration levels. The experiment also compared treatment results between a conventional reactor and an aquatic worm reactor (WR). Results indicated that the recommended concentration of dissolved oxygen (DO) was 2.5 mg L(-1). The removal rate of chemical oxygen demand remained steady at 80% when the DO concentration was higher than 2.5 mg L(-1), while the removal rate of ammonia nitrogen continued to moderately increase. Increasing the DO concentration to 5 mg L(-1) did not improve sludge reduction, and consumed more power. With a DO concentration of 2.5 mg L(-1) and a power of 0.19 kWh t(-1) water, the absolute sludge reduction and relative sludge reduction rates in the WR were 60.0% and 45.7%, respectively, and the daily aquatic worm growth rate was 0.150 d(-1) during the 17-d test. Therefore, at the recommended aeration regime, aquatic worms reduced the sludge without increasing the power consumption or deteriorating the effluent.

  20. Cardiopulmonary changes with aeration of the newborn lung.

    PubMed

    Hooper, Stuart Brian; Polglase, Graeme Roger; Roehr, Charles Christoph

    2015-06-01

    The newborn's transition from fetal to neonatal life includes aeration of the lungs, establishment of pulmonary gas exchange and changing the fetal circulation into the adult phenotype. This review summarizes the latest research findings, which show that lung aeration, airway liquid clearance and cardiovascular changes are directly interconnected at birth. The mechanisms of airway liquid clearance at birth are reviewed and the particular importance of the transpulmonary pressure gradient during lung aeration is discussed. Further, we summarize research findings which prove that lung aeration triggers the increase in pulmonary blood flow (PBF) at birth, and how the increase in PBF secures the preload for left ventricular output. Consequently, we review animal experiments which suggest that delaying umbilical cord clamping until breathing commences facilitates hemodynamic stability during transition. These data are reviewed with respect to the clinical applicability: As lung aeration is the key to successful transition to newborn life, providing adequate respiratory support at birth must be the primary objective of neonatal staff attending to the newborn infant. Clinical studies are needed to demonstrate whether the obvious benefits of delaying cord clamping until breathing commences hold true in human babies.

  1. Cardiopulmonary changes with aeration of the newborn lung

    PubMed Central

    Hooper, Stuart Brian; Polglase, Graeme Roger; Roehr, Charles Christoph

    2015-01-01

    The newborns transition from fetal to neonatal life includes aeration of the lungs, establishment of pulmonary gas exchange and a changing the fetal circulation into the adult phenotype. This review summarizes the latest research findings, which show that lung aeration, airway liquid clearance and cardiovascular changes are directly interconnected at birth. The mechanisms of airway liquid clearance at birth are reviewed and the particular importance of the transpulmonary pressure gradient during lung aeration is discussed. Further, we summarize research findings which prove that lung aeration triggers the increased in pulmonary blood flow (PBF) at birth, and how the increase in PBF secures the preload for left ventricular output. Consequently, we review animal experiments which suggest that delaying umbilical cord clamping until breathing commences facilitates hemodynamic stability during transition. These data are reviewed with respect to the clinical applicability: As lung aeration is the key to successful transition to newborn life, providing adequate respiratory support at birth must be the primary objective of neonatal staff attending to the newborn infant. Clinical studies are needed to demonstrate whether the obvious benefits of delaying cord clamping until breathing commences hold true in human babies. PMID:25870083

  2. TANK 50 BATCH 0 SALTSTONE FORMULATION CONFIRMATION

    SciTech Connect

    Langton, C.

    2006-06-05

    Savannah River National Laboratory (SRNL) personnel were requested to confirm the Tank 50 Batch 0 grout formulation per Technical Task Request, SSF-TTR-2006-0001 (task 1 of 2) [1]. Earlier Batch 0 formulation testing used a Tank 50 sample collected in September 2005 and is described elsewhere [2]. The current testing was performed using a sample of Tank 50 waste collected in May 2006. This work was performed according to the Technical Task and Quality Assurance Plan (TT/QAP), WSRC-RP-2006-00594 [3]. The salt solution collected from Tank 50 in May 2006 contained approximately 3 weight percent more solids than the sample collected in September 2005. The insoluble solids took longer to settle in the new sample which was interpreted as indicating finer particles in the current sample. The saltstone formulation developed for the September 2005 Tank 50 Batch 0 sample was confirmed for the May 2006 sample with one minor exception. Saltstone prepared with the Tank 50 sample collected in May 2006 required 1.5 times more Daratard 17 set retarding admixture than the saltstone prepared with the September In addition, a sample prepared with lower shear mixing (stirring with a spatula) had a higher plastic viscosity (57 cP) than samples made with higher shear mixing in a blender (23cP). The static gel times of the saltstone slurries made with low shear mixing were also shorter ({approx}32 minutes) than those for comparable samples made in the blender ({approx}47 minutes). The addition of the various waste streams (ETP, HEU-HCAN, and GPE-HCAN) to Tank 50 from September 2005 to May 2006 has increased the amount of set retarder, Daratard 17, required for processing saltstone slurries through the Saltstone facility. If these streams are continued to be added to Tank 50, the quantity of admixtures required to maintain the same processing conditions for the Saltstone facility will probably change and additional testing is recommended to reconfirm the Tank 50 Saltstone formulation.

  3. Tank characterization report: Tank 241-C-109

    SciTech Connect

    Simpson, B.C.; Borshiem, G.L.; Jensen, L.

    1993-09-01

    Single-shell tank 241-C-109 is a Hanford Site Ferrocyanide Watch List tank that was most recently sampled in September 1992. Analyses of materials obtained from tank 241-C-109 were conducted to support the resolution of the ferrocyanide unreviewed safety question (USQ) and to support Hanford Federal Facility Agreement and consent Order (Tri- Party Agreement) Milestone M-10-00. This report describes this analysis.

  4. In situ groundwater aeration of polycyclic aromatic hydrocarbons

    SciTech Connect

    Symons, B.D.; Linkenheil, R.; Pritchard, D.; Shanke, C.A.; Seep, D.

    1995-12-31

    At a former wood treating site in Minnesota, the feasibility of in situ groundwater aeration was investigated in a laboratory treatability setting, to evaluate biodegradability and optimal operation conditions of the site aquifer. After concluding that an aeration system would increase the dissolved oxygen concentrations in the groundwater enough to sustain microbial life, a field demonstration system was designed and installed. The system was operated for 1 year, during which groundwater quality at upgradient and downgradient wells was monitored to evaluate the system`s effectiveness. The groundwater aeration system successfully reduced groundwater polycyclic aromatic hydrocarbon (PAH) concentrations, especially naphthalene. Naphthalene concentrations were reduced from 1,319 {micro}g/L to below the laboratory detection limit of 0.5 {micro}g/L. Cumulative concentrations of other PAH compounds were reduced from 98 {micro}g/L to 23 {micro}g/L during the 1-year test.

  5. Tank Characterization Report for Single Shell Tank 241-C-104

    SciTech Connect

    ADAMS, M.R.

    2000-04-06

    Interprets information about the tank answering a series of six questions covering areas such as information drivers, tank history, tank comparisons, disposal implications, data quality and quantity, and unique aspects of the tank.

  6. Aeration for plant root respiration in a tidal marsh

    NASA Astrophysics Data System (ADS)

    Li, Hailong; Li, Ling; Lockington, David

    2005-06-01

    This paper investigates the tidal effects on aeration conditions for plant root respiration in a tidal marsh. We extend the work of Ursino et al. (2004) by using a two-phase model for air and water flows in the marsh. Simulations have been conducted to examine directly the link between the airflow dynamics and the aeration condition in the marsh soil. The results show that the effects of entrapped air on water movement in the vadose zone are significant in certain circumstances. Single-phase models based on Richards' equation, which neglect such effects, may not be adequate for quantifying the aeration condition in tidal marsh. The optimal aeration condition, represented by the maximum of the integral magnitude of tidally advected air mass (TAAM) flux, is found to occur near the tidal creek for the four soil textures simulated. This may explain the observation that some salt marsh plant species grow better near tidal creeks than in the inner marsh areas. Our analyses, based on the two-phase model and predicted TAAM flux magnitude, provide further insight into the "positive feedback" mechanism proposed by Ursino et al. (2004). That is, pioneer plants may grow successfully near the creek where the root aeration condition is optimal. The roots of the pioneer plants can soften and loosen the rhizosphere soil, which increases the evapotranspiration rate, the soil porosity, and absolute permeability and weakens the capillary effects. These, in turn, improve further the root aeration conditions and may lead to colonization by plants less resistant to anaerobic conditions.

  7. Aeration for plant root respiration in a tidal marsh

    NASA Astrophysics Data System (ADS)

    Li, Hailong; Li, Ling; Lockington, David

    2005-06-01

    This paper investigates the tidal effects on aeration conditions for plant root respiration in a tidal marsh. We extend the work of Ursino et al. (2004) by using a two-phase model for air and water flows in the marsh. Simulations have been conducted to examine directly the link between the airflow dynamics and the aeration condition in the marsh soil. The results show that the effects of entrapped air on water movement in the vadose zone are significant in certain circumstances. Single-phase models based on Richards' equation, which neglect such effects, may not be adequate for quantifying the aeration condition in tidal marsh. The optimal aeration condition, represented by the maximum of the integral magnitude of tidally advected air mass (TAAM) flux, is found to occur near the tidal creek for the four soil textures simulated. This may explain the observation that some salt marsh plant species grow better near tidal creeks than in the inner marsh areas. Our analyses, based on the two-phase model and predicted TAAM flux magnitude, provide further insight into the ``positive feedback'' mechanism proposed by Ursino et al. (2004). That is, pioneer plants may grow successfully near the creek where the root aeration condition is optimal. The roots of the pioneer plants can soften and loosen the rhizosphere soil, which increases the evapotranspiration rate, the soil porosity, and absolute permeability and weakens the capillary effects. These, in turn, improve further the root aeration conditions and may lead to colonization by plants less resistant to anaerobic conditions.

  8. Tessaracoccus defluvii sp. nov., isolated from an aeration tank of a sewage treatment plant.

    PubMed

    Srinivasan, Sathiyaraj; Sundararaman, Aravind; Lee, Sang-Seob

    2017-01-01

    A Gram-positive, non-motile, aerobic, coccus-shaped bacterium, designated strain LNB-140(T), was isolated from a sewage treatment plant in the Republic of Korea and was characterised using a polyphasic taxonomic approach. Comparative 16S rRNA gene sequence analysis showed that strain LNB-140(T) belongs to genus Tessaracoccus in the family Propionibacteriaceae of the phylum Actinobacteria. The 16S rRNA gene sequence similarities between strain LNB-140(T) and type strains of the genus, Tessaracoccus flavescens SST-39(T) and Tessaracoccus rhinocerotis YIM101269(T) are 97.8 and 97.4 %, respectively. The chemotaxonomic properties of strain LNB-140(T) are consistent with those of members of the genus Tessaracoccus: a quinone system with MK-9(H4) as the predominant menaquinone; anteiso-C15:0 and iso C15:0 as the predominant cellular fatty acids; and LL-2,6-diaminopimelic acid as the diagnostic peptidoglycan diamino acid. The major polar lipids were identified as diphosphatidylglycerol and phosphatidylethanolamine. The G+C content of the genomic DNA was determined to be 67.1 mol%. Differential phenotypic properties along with low DNA-DNA relatedness (<30 ± 3.2 %) with closely related type strains show that strain LNB-140(T) is distinct from previously described members of the genus Tessaracoccus and represents a novel species in this genus, for which the name Tessaracoccus defluvii sp. nov. is proposed. The type strain is LNB-140(T) (=KEMB 5401-076(T) = JCM 17540(T)).

  9. Contact Aeration Wastewater Treatment Plant Upgrading Evaluation, Reese Air Force Base, Texas.

    DTIC Science & Technology

    1979-11-01

    id* If negoeory sruidanilU y bl Wok nusm) A 1940 vintage contact aeration wastewater treatment (Hays Process ) plant at Reese APE TX was upgraded by...aeration process is presented. The pet.rmance effticiencies of the Reese APE contact aeration treatment plant before and after upgrading are presented...Efeve SE~CURITY CLASSIFICATION OF TbIISP AGECIWa.. Does #ntiorgo). contact aeration process . It was found that the performance efficiencies of the

  10. Comparative hydraulics of two fishery research circular tanks and recommendations for control of experimental bias

    USGS Publications Warehouse

    Odeh, M.; Schrock, R.M.; Gannam, A.

    2003-01-01

    Hydraulic characteristics inside two research circular tanks (1.5-m and 1.2-m diameter) with the same volume of water were studied to understand how they might affect experimental bias by influencing the behavior and development of juvenile fish. Water velocities inside each tank were documented extensively and flow behavior studied. Surface inflow to the 1.5-m tank created a highly turbulent and aerated surface, and produced unevenly distributed velocities within the tank. A low-flow velocity, or "dead" zone, persisted just upstream of the surface inflow. A single submerged nozzle in the 1.2-m tank created uniform flow and did not cause undue turbulence or introduce air. Flow behavior in the 1.5-m tank is believed to have negatively affected the feeding behavior and physiological development of a group of juvenile fall chinook salmon, Oncorhynchus tshawytscha. A new inflow nozzle design provided comparable flow behavior regardless of tank size and water depth. Maintaining similar hydraulic conditions inside tanks used for various biological purposes, including fish research, would minimize experimental bias caused by differences in flow behavior. Other sources of experimental bias are discussed and recommendations given for reporting and control of experimental conditions in fishery research tank experiments.

  11. Gimballed Shoulders for Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Carter, Robert; Lawless, Kirby

    2008-01-01

    In a proposed improvement of tooling for friction stir welding, gimballed shoulders would supplant shoulders that, heretofore, have been fixedly aligned with pins. The proposal is especially relevant to self-reacting friction stir welding. Some definitions of terms, recapitulated from related prior NASA Tech Briefs articles, are prerequisite to a meaningful description of the proposed improvement. In friction stir welding, one uses a tool that includes (1) a rotating shoulder on top (or front) of the workpiece and (2) a pin that rotates with the shoulder and protrudes from the shoulder into the depth of the workpiece. In conventional friction stir welding, the main axial force exerted by the tool on the workpiece is reacted through a ridged backing anvil under (behind) the workpiece. When conventional friction stir welding is augmented with an auto-adjustable pin-tool (APT) capability, the depth of penetration of the pin into the workpiece is varied in real time by a position- or forcecontrol system that extends or retracts the pin as needed to obtain the desired effect. In self-reacting (also known as self-reacted) friction stir welding as practiced heretofore, there are two shoulders: one on top (or front) and one on the bottom (or back) of the workpiece. In this case, a threaded shaft protrudes from the tip of the pin to beyond the back surface of the workpiece. The back shoulder is held axially in place against tension by a nut on the threaded shaft. Both shoulders rotate with the pin and remain aligned coaxially with the pin. The main axial force exerted on the workpiece by the tool and front shoulder is reacted through the back shoulder and the threaded shaft into the friction-stir-welding machine head, so that a backing anvil is no longer needed. A key transmits torque between the bottom shoulder and the threaded shaft, so that the bottom shoulder rotates with the shaft. This concludes the prerequisite definitions of terms.

  12. Tank 241-SX-103 tank characterization plan

    SciTech Connect

    Homi, C.S.

    1995-03-08

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory, and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-SX-103.

  13. Tank 241-U-103 tank characterization plan

    SciTech Connect

    Carpenter, B.C.

    1995-01-24

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, Oak Ridge National Laboratory and PNL tank vapor program. The scope of this plan is to provide guidance for the sampling and analysis of vapor samples from tank 241-U-103.

  14. Liquid rocket metal tanks and tank components

    NASA Technical Reports Server (NTRS)

    Wagner, W. A.; Keller, R. B. (Editor)

    1974-01-01

    Significant guidelines are presented for the successful design of aerospace tanks and tank components, such as expulsion devices, standpipes, and baffles. The state of the art is reviewed, and the design criteria are presented along with recommended practices. Design monographs are listed.

  15. Temperature stratification and insect pest populations in stored wheat with suction versus pressure aeration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A three-year study was conducted to compare temperature profiles in the headspace and in the bulk mass of wheat aerated through pressure aeration and suction aeration. Insect pitfall traps were used to measure naturally-occurring populations of stored product insects. Results show uniform distributi...

  16. Dissolved Oxygen management in catfish ponds using electric paddlewheel aerators: new approaches with old technology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The electric paddlewheel aerator has been the main aerator used in the U.S. catfish industry for the post forty years. While it has its limitations, it is perhaps the most efficient shallow-water aerator yet to be developed. Its shortcomings result not so much from poor design, as from poor usage. U...

  17. Development and evaluation of a new aerator for the catfish industry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Traditional paddle-wheel aerators have been used for supplemental and emergency aeration in the aquaculture industry for over 30 years but distribute a high volume of water which dilutes the aeration effort over the entire pond volume. Thus, a great deal of equipment and a large amount of power is r...

  18. Flammable gas tank safety program: Technical basis for gas analysis and monitoring

    SciTech Connect

    Sherwood, D.J.

    1995-09-08

    Flammable gases generated in radioactive liquids. Twenty-five high level radioactive liquid waste storage tanks located underground at the Hanford Site are on a Flammable Gas Watch List because they contain waste which tends to retain the gases generated in it until rather large quantities are available for sudden release to the tank head space; if a tank is full it has little dome space, and a flammable concentration of gases could be produced--even if the tank is ventilated. If the waste has no tendency to retain gas generated in it then a continual flammable gas concentration in the tank dome space is established by the gas production rate and the tank ventilation rate (or breathing rate for unventilated tanks); this is also a potential problem for Flammable Gas Watch List tanks, and perhaps other Hanford tanks too. All Flammable Gas Watch List tanks will be fitted with Standard Hydorgen Monitoring Systems so that their behavior can be observed. In some cases, such as tank 241-SY-101, the data gathered from such observations will indicate that tank conditions need to be mitigated so that gas release events are either eliminated or rendered harmless. For example, a mixer pump was installed in tank 241-SY-101; operating the pump stirs the waste, replacing the large gas release events with small releases of gas that are kept below twenty-five percent of the lower flammability limit by the ventilation system. The concentration of hydrogen measured in Hanford waste tanks is greater than that of any other flammable gas. Hydrogen levels measured with a Standard Hydrogen Monitoring System in excess of 0.6 volume percent will cause Westinghouse Hanford Company to consider actions which will decrease the amount of flammable gas in the tank

  19. Ammonia tank failure

    SciTech Connect

    Sweat, M.E.

    1983-04-01

    An ammonia tank failure at Hawkeye Chemical of Clinton, Iowa is discussed. The tank was a double-wall, 27,000 metric-ton tank built in 1968 and commissioned in December 1969. The paper presented covers the cause of the failure, repair, and procedural changes made to prevent recurrence of the failure. (JMT)

  20. Feed tank transfer requirements

    SciTech Connect

    Freeman-Pollard, J.R.

    1998-09-16

    This document presents a definition of tank turnover; DOE responsibilities; TWRS DST permitting requirements; TWRS Authorization Basis (AB) requirements; TWRS AP Tank Farm operational requirements; unreviewed safety question (USQ) requirements; records and reporting requirements, and documentation which will require revision in support of transferring a DST in AP Tank Farm to a privatization contractor for use during Phase 1B.

  1. 49 CFR 174.63 - Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank car...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Packagings, cargo tanks, and multi-unit tank car tanks. 174.63 Section 174.63 Transportation Other....63 Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank car..., Large Packaging, cargo tank, or multi-unit tank car tank) containing a hazardous material in...

  2. 49 CFR 174.63 - Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank car...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Packagings, cargo tanks, and multi-unit tank car tanks. 174.63 Section 174.63 Transportation Other....63 Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank car..., Large Packaging, cargo tank, or multi-unit tank car tank) containing a hazardous material in...

  3. 49 CFR 174.63 - Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank car...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Packagings, cargo tanks, and multi-unit tank car tanks. 174.63 Section 174.63 Transportation Other....63 Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank car..., Large Packaging, cargo tank, or multi-unit tank car tank) containing a hazardous material in...

  4. 49 CFR 174.63 - Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank car...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Packagings, cargo tanks, and multi-unit tank car tanks. 174.63 Section 174.63 Transportation Other....63 Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank car tanks. (a) A carrier may not transport a bulk packaging (e.g., portable tank, IM portable tank,...

  5. Non-autoclaved aerated concrete with mineral additives

    NASA Astrophysics Data System (ADS)

    Il'ina, L. V.; Rakov, M. A.

    2016-01-01

    We investigated the effect of joint grinding of Portland cement clinker, silica and carbonate components and mineral additives to specific surface of 280 - 300 m2/kg on the properties (strength, average density and thermal conductivity) of non-autoclaved aerated concrete, and the porosity of the hardened cement paste produced from Portland cement clinker with mineral additives. The joint grinding of the Portland cement clinker with silica and carbonate components and mineral additives reduces the energy consumption of non-autoclaved aerated concrete production. The efficiency of mineral additives (diopside, wollastonite) is due to the closeness the composition, the type of chemical bonds, physical and chemical characteristics (specific enthalpy of formation, specific entropy) to anhydrous clinker minerals and their hydration products. Considering the influence of these additions on hydration of clinker minerals and formation of hardened cement paste structure, dispersed wollastonite and diopside should be used as mineral additives. The hardness and, consequently, the elastic modulus of diopside are higher than that of hardened cement paste. As a result, there is a redistribution of stresses in the hardened cement paste interporous partitions and hardening, both the partitions and aerated concrete on the whole. The mineral additives introduction allowed to obtain the non-autoclaved aerated concrete with average density 580 kg/m3, compressive strength of 3.3 MPa and thermal conductivity of 0.131 W/(m.°C).

  6. Landfill aeration for emission control before and during landfill mining.

    PubMed

    Raga, Roberto; Cossu, Raffaello; Heerenklage, Joern; Pivato, Alberto; Ritzkowski, Marco

    2015-12-01

    The landfill of Modena, in northern Italy, is now crossed by the new high velocity railway line connecting Milan and Bologna. Waste was completely removed from a part of the landfill and a trench for the train line was built. With the aim of facilitating excavation and further disposal of the material extracted, suitable measures were defined. In order to prevent undesired emissions into the excavation area, the aerobic in situ stabilisation by means of the Airflow technology took place before and during the Landfill Mining. Specific project features involved the pneumatic leachate extraction from the aeration wells (to keep the leachate table low inside the landfill and increase the volume of waste available for air migration) and the controlled moisture addition into a limited zone, for a preliminary evaluation of the effects on process enhancement. Waste and leachate were periodically sampled in the landfill during the aeration before the excavation, for quality assessment over time; the evolution of biogas composition in the landfill body and in the extraction system for different plant set-ups during the project was monitored, with specific focus on uncontrolled migration into the excavation area. Waste biological stability significantly increased during the aeration (waste respiration index dropped to 33% of the initial value after six months). Leachate head decreased from 4 to 1.5m; leachate recirculation tests proved the beneficial effects of moisture addition on temperature control, without hampering waste aerobization. Proper management of the aeration plant enabled the minimization of uncontrolled biogas emissions into the excavation area.

  7. Aerated Lagoons. Instructor's Guide. Biological Treatment Process Control.

    ERIC Educational Resources Information Center

    Andersen, Lorri

    This unit (which consists of a single lesson) describes the structural and operationally unique features of aerated lagoons. In addition, special troubleshooting and maintenance problems are discussed. The instructor's guide for the unit includes: (1) an overview of the lesson; (2) lesson plan; (3) lecture outline (keyed to a set of slides used…

  8. Towards advanced aeration modelling: from blower to bubbles to bulk.

    PubMed

    Amaral, Andreia; Schraa, Oliver; Rieger, Leiv; Gillot, Sylvie; Fayolle, Yannick; Bellandi, Giacomo; Amerlinck, Youri; Mortier, Séverine T F C; Gori, Riccardo; Neves, Ramiro; Nopens, Ingmar

    2017-02-01

    Aeration is an essential component of aerobic biological wastewater treatment and is the largest energy consumer at most water resource recovery facilities. Most modelling studies neglect the inherent complexity of the aeration systems used. Typically, the blowers, air piping, and diffusers are not modelled in detail, completely mixed reactors in a series are used to represent plug-flow reactors, and empirical correlations are used to describe the impact of operating conditions on bubble formation and transport, and oxygen transfer from the bubbles to the bulk liquid. However, the mechanisms involved are very complex in nature and require significant research efforts. This contribution highlights why and where there is a need for more detail in the different aspects of the aeration system and compiles recent efforts to develop physical models of the entire aeration system (blower, valves, air piping and diffusers), as well as adding rigour to the oxygen transfer efficiency modelling (impact of viscosity, bubble size distribution, shear and hydrodynamics). As a result of these model extensions, more realistic predictions of dissolved oxygen profiles and energy consumption have been achieved. Finally, the current needs for further model development are highlighted.

  9. 5. AERATOR VIEW FROM DOWNSTREAM. FLUSH VALVE AT RIGHT OPENS ...

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

    5. AERATOR VIEW FROM DOWNSTREAM. FLUSH VALVE AT RIGHT OPENS TO CLEAR THE SYSTEM ABOVE THE SILT AND DEBRIS AND TO STOP THE FLOW OF WATER INTO THE SYSTEM DOWN LINE. BOX FLUME CONTINUES DOWN LINE TO SEDIMENTATION CHAMBER. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

  10. Renewable energy for the aeration of wastewater ponds.

    PubMed

    Hobus, I; Hegemann, W

    2003-01-01

    The application of a decentralised renewable energy supply for the aeration of wastewater ponds, and the influence of an unsteady oxygen supply on the specific conversion rate and biocoenose was investigated. With the discontinuous aeration the specific conversion rate is increased as compared to facultative ponds. The estimation of the microorganisms consortia was done with in situ hybridisation techniques. A significant shift in the bacteria population with the chosen specific probes for anaerobic, sulphate reducing and nitrifying bacteria could not be detected. Wastewater ponds have sufficient buffer volume to compensate for the fluctuating energy supply. But the efficiency of the energy supply of a photovoltaic plant decreases in shallow lakes (d < 1.5 m) corresponding to a high oxygen production of algae. For the layout of the individual components: photovoltaic and wind power plant, energy management, aeration system and wastewater pond, a simulation model was developed and tested. The application of renewable energy for the aeration of wastewater ponds is a useful alternative for the redevelopment of overloaded ponds as well as the construction of new wastewater ponds, especially in areas with an inadequate central electricity grid and a high availability of wind and solar energy.

  11. 4. AERATOR AT 525, CONSTRUCTED 19371938, VIEW FROM UPSTREAM (TRASH ...

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

    4. AERATOR AT 525, CONSTRUCTED 1937-1938, VIEW FROM UPSTREAM (TRASH SCREEN REMOVED FOR CLARITY), WATER FROM INTAKE FLOWS THROUGH FLUME, THEN DAMS, AND SPILLS OVER STEPS TO MIX WITH OXYGEN, THUS REDUCING ACIDITY LEVELS. ACID INDUCES FASTER CORROSION OF PIPES AND SPOILS TASTE. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

  12. MODELING ANALYSIS FOR GROUT HOPPER WASTE TANK

    SciTech Connect

    Lee, S.

    2012-01-04

    The Saltstone facility at Savannah River Site (SRS) has a grout hopper tank to provide agitator stirring of the Saltstone feed materials. The tank has about 300 gallon capacity to provide a larger working volume for the grout nuclear waste slurry to be held in case of a process upset, and it is equipped with a mechanical agitator, which is intended to keep the grout in motion and agitated so that it won't start to set up. The primary objective of the work was to evaluate the flow performance for mechanical agitators to prevent vortex pull-through for an adequate stirring of the feed materials and to estimate an agitator speed which provides acceptable flow performance with a 45{sup o} pitched four-blade agitator. In addition, the power consumption required for the agitator operation was estimated. The modeling calculations were performed by taking two steps of the Computational Fluid Dynamics (CFD) modeling approach. As a first step, a simple single-stage agitator model with 45{sup o} pitched propeller blades was developed for the initial scoping analysis of the flow pattern behaviors for a range of different operating conditions. Based on the initial phase-1 results, the phase-2 model with a two-stage agitator was developed for the final performance evaluations. A series of sensitivity calculations for different designs of agitators and operating conditions have been performed to investigate the impact of key parameters on the grout hydraulic performance in a 300-gallon hopper tank. For the analysis, viscous shear was modeled by using the Bingham plastic approximation. Steady state analyses with a two-equation turbulence model were performed. All analyses were based on three-dimensional results. Recommended operational guidance was developed by using the basic concept that local shear rate profiles and flow patterns can be used as a measure of hydraulic performance and spatial stirring. Flow patterns were estimated by a Lagrangian integration technique along the

  13. Ventilation/perfusion mismatch during lung aeration at birth.

    PubMed

    Lang, Justin A R; Pearson, James T; te Pas, Arjan B; Wallace, Megan J; Siew, Melissa L; Kitchen, Marcus J; Fouras, Andreas; Lewis, Robert A; Wheeler, Kevin I; Polglase, Graeme R; Shirai, Mikiyasu; Sonobe, Takashi; Hooper, Stuart B

    2014-09-01

    At birth, the transition to newborn life is triggered by lung aeration, which stimulates a large increase in pulmonary blood flow (PBF). Current theories predict that the increase in PBF is spatially related to ventilated lung regions as they aerate after birth. Using simultaneous phase-contrast X-ray imaging and angiography we investigated the spatial relationships between lung aeration and the increase in PBF after birth. Six near-term (30-day gestation) rabbits were delivered by caesarean section, intubated and an intravenous catheter inserted, before they were positioned for X-ray imaging. During imaging, iodine was injected before ventilation onset, after ventilation of the right lung only, and after ventilation of both lungs. Unilateral ventilation increased iodine levels entering both left and right pulmonary arteries (PAs) and significantly increased heart rate, iodine ejection per beat, diameters of both left and right PAs, and number of visible vessels in both lungs. Within the 6th intercostal space, the mean gray level (relative measure of iodine level) increased from 68.3 ± 11.6 and 70.3 ± 7.5%·s to 136.3 ± 22.6 and 136.3 ± 23.7%·s in the left and right PAs, respectively. No differences were observed between vessels in the left and right lungs, despite the left lung not initially being ventilated. The increase in PBF at birth is not spatially related to lung aeration allowing a large ventilation/perfusion mismatch, or pulmonary shunting, to occur in the partially aerated lung at birth.

  14. The potential for aeration of MSW landfills to accelerate completion

    SciTech Connect

    Rich, Charlotte; Gronow, Jan; Voulvoulis, Nikolaos

    2008-07-01

    Landfilling is a popular waste disposal method, but, as it is practised currently, it is fundamentally unsustainable. The low short-term financial costs belie the potential long-term environmental costs, and traditional landfill sites require long-term management in order to mitigate any possible environmental damage. Old landfill sites might require aftercare for decades or even centuries, and in some cases remediation may be necessary. Biological stabilisation of a landfill is the key issue; completion criteria provide a yardstick by which the success of any new technology may be measured. In order for a site to achieve completion it must pose no risk to human health or the environment, meaning that attenuation of any emissions from the site must occur within the local environment without causing harm. Remediation of old landfill sites by aerating the waste has been undertaken in Germany, the United States, Italy and The Netherlands, with considerable success. At a pilot scale, aeration has also been used in newly emplaced waste to accelerate stabilisation. This paper reviews the use of aerobic landfill worldwide, and assesses the ways in which the use of aerobic landfill techniques can decrease the risks associated with current landfill practices, making landfill a more sustainable waste disposal option. It focuses on assessing ways to utilise aeration to enhance stabilisation. The results demonstrated that aeration of old landfill sites may be an efficient and cost-effective method of remediation and allow the date of completion to be brought forward by decades. Similarly, aeration of newly emplaced waste can be effective in enhancing degradation, assisting with completion and reducing environmental risks. However, further research is required to establish what procedure for adding air to a landfill would be most suitable for the UK and to investigate new risks that may arise, such as the possible emission of non-methane organic compounds.

  15. Tank 241-B-103 tank characterization plan

    SciTech Connect

    Carpenter, B.C.

    1995-01-23

    The Defense Nuclear Facilities Safety Board (DNFSB) has advised the US Department of Energy (DOE) to concentrate the near-term sampling and analysis activities on identification and resolution of safety issues. The data quality objective (DQO) process was chosen as a tool to be used to identify sampling and analytical needs for the resolution of safety issues. As a result, a revision in the Federal Facility Agreement and Consent Order (Tri-Party Agreement or TPA) milestone M-44-00 has been made, which states that ``A Tank Characterization Plan (TCP) will also be developed for each double-shell tank (DST) and single-shell tank (SST) using the DQO process... Development of TCPs by the DQO process is intended to allow users (e.g., Hanford Facility user groups, regulators) to ensure their needs will be met and that resources are devoted to gaining only necessary information.`` This document satisfies that requirement for Tank 241-B-103 (B-103) sampling activities. Tank B-103 was placed on the Organic Watch List in January 1991 due to review of TRAC data that predicts a TOC content of 3.3 dry weight percent. The tank was classified as an assumed leaker of approximately 30,280 liters (8,000 gallons) in 1978 and declared inactive. Tank B-103 is passively ventilated with interim stabilization and intrusion prevention measures completed in 1985.

  16. Selecting fuel storage tanks

    SciTech Connect

    Doherty, R. )

    1993-07-01

    Until the use of underground storage tanks (USTs) for fuel storage was mandated by the 1970 Uniform Fire Code, above-ground storage tanks (ASTs) were widely used. The tanks were relatively crude by today's standards so the technical superiority and fire protection afforded by use of underground tanks soon made USTs the system of choice for almost all uses. As a result, tens of thousands of tanks have been underground for more than 20 years, and at some point, many of them began leaking. Often, the first sign of these leaks appeared when groundwater became contaminated. The EPA responded to this major environmental problem by strictly regulating the use of below-ground tanks to store flammable liquids. These added regulations have had a severe effect on both service stations and private fueling. The removal of underground tanks and the removal and disposal of any contaminated soil is an extremely expensive proposition. Furthermore, new Uniform Fire Code regulations have added to the costs, imposing requirements for double-walled tanks, corrosion protection, electronic leak monitoring, and annual tank testing. These requirements, plus the financial responsibility requirements the EPA imposed on owners and users of below-ground tanks, led directly to a reconsideration of the use of above-ground tanks for some applications.

  17. Friction Stir Welding of Steel Alloys

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey; Munafo, Paul M. (Technical Monitor)

    2001-01-01

    The friction stir welding process has been developed primarily for the welding of aluminum alloys. Other higher melting allows such, as steels are much more difficult to join. Special attention must be given to pin tool material selection and welding techniques. This paper addresses the joining of steels and other high melting point materials using the friction stir welding process. Pin tool material and welding parameters will be presented. Mechanical properties of weldments will also be presented. Significance: There are many applications for the friction stir welding process other than low melting aluminum alloys. The FSW process can be expanded for use with high melting alloys in the pressure vessel, railroad and ship building industries.

  18. The continuous production of stir cast material

    NASA Astrophysics Data System (ADS)

    Hamoen, A.

    1986-06-01

    The production of AlSi8 extrusion billets using a semicontinuous caster is described. The continuous casting process and the process parameters are outlined. The mathematical model, developed to calculate the temperature distribution within the billet during casting as a function of the process parameters, is explained. Quality control focussed on inversion segregation which causes the formation of a surface layer with a different structure and composition, imposing peeling of billets. Product development focussed on the production of stir-cast material of the same AlSi8 alloy. The use of AlSi8 as a wrought alloy by modification of the structure by stirring is discussed.

  19. 49 CFR 179.400 - General specification applicable to cryogenic liquid tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... liquid tank car tanks. 179.400 Section 179.400 Transportation Other Regulations Relating to... MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and... liquid tank car tanks....

  20. Redox potential driven aeration during very-high-gravity ethanol fermentation by using flocculating yeast

    PubMed Central

    Liu, Chen-Guang; Hao, Xue-Mi; Lin, Yen-Han; Bai, Feng-Wu

    2016-01-01

    Ethanol fermentation requires oxygen to maintain high biomass and cell viability, especially under very-high-gravity (VHG) condition. In this work, fermentation redox potential (ORP) was applied to drive the aeration process at low dissolved oxygen (DO) levels, which is infeasible to be regulated by a DO sensor. The performance and characteristics of flocculating yeast grown under 300 and 260 g glucose/L conditions were subjected to various aeration strategies including: no aeration; controlled aeration at −150, −100 and −50 mV levels; and constant aeration at 0.05 and 0.2 vvm. The results showed that anaerobic fermentation produced the least ethanol and had the highest residual glucose after 72 h of fermentation. Controlled aerations, depending on the real-time oxygen demand, led to higher cell viability than the no-aeration counterpart. Constant aeration triggered a quick biomass formation, and fast glucose utilization. However, over aeration at 0.2 vvm caused a reduction of final ethanol concentration. The controlled aeration driven by ORP under VHG conditions resulted in the best fermentation performance. Moreover, the controlled aeration could enhance yeast flocculating activity, promote an increase of flocs size, and accelerate yeast separation near the end of fermentation. PMID:27161047

  1. Study of stirred layers on 316L steel created by friction stir processing

    NASA Astrophysics Data System (ADS)

    Langlade, C.; Roman, A.; Schlegel, D.; Gete, E.; Folea, M.

    2014-08-01

    Nanostructured materials are known to exhibit attractive properties, especially in the mechanical field where high hardness is of great interest. The friction stir process (FSP) is a recent surface engineering technique derived from the friction stir welding method (FSW). In this study, the FSP of an 316L austenitic stainless steel has been evaluated. The treated layers have been characterized in terms of hardness and microstructure and these results have been related to the FSP operational parameters. The process has been analysed using a Response Surface Method (RSM) to enable the stirred layer thickness prediction.

  2. Control of Protein Crystal Nucleation and Growth Using Stirring Solution

    NASA Astrophysics Data System (ADS)

    Niino, Ai; Adachi, Hiroaki; Takano, Kazufumi; Matsumura, Hiroyoshi; Kinoshita, Takayoshi; Warizaya, Masaichi; Inoue, Tsuyoshi; Mori, Yusuke; Sasaki, Takatomo

    2004-11-01

    We have previously developed a protein crystallization technique using a stirring protein solution and revealed that (i) continuous stirring prevents excess spontaneous nucleation and accelerates the growth of protein crystals and (ii) prestirring (solution stirring in advance) promotes the crystal nucleation of hen egg-white lysozyme. In bovine adenosine deaminase (ADA) crystallization, continuous stirring improves the crystal quality but elongates the nucleation time. In this paper, in order to control both the crystal nucleation and growth of ADA using a Micro-Stirring technique, we carried out five different stirring patterns such as (i) no stirring, (ii) continuous stirring, (iii) prestirring, (iv) poststirring (stirring late in the growth period) and (v) restirring (combined pre- and poststirring). The results showed that high-quality well-shaped crystals were obtained under the continuous stirring and restirring conditions and the nucleation time under the prestirring and restirring conditions was shorter than that under the continuous stirring and poststirring conditions. Consequently, high-quality crystals were promptly obtained under the restirring condition. These results suggest that we are able to control both the nucleation and growth of protein crystals with the stirring techniques.

  3. Effective pine bark composting with the Dome Aeration Technology

    SciTech Connect

    Trois, Cristina . E-mail: troisc@ukzn.ac.za; Polster, Andreas

    2007-07-01

    In South Africa garden refuse is primarily disposed of in domestic landfills. Due to the large quantities generated, any form of treatment would be beneficial for volume reduction, waste stabilization and resource recovery. Dome Aeration Technology (DAT) is an advanced process for aerobic biological degradation of garden refuse and general waste [Paar, S., Brummack, J., Gemende, B., 1999a. Advantages of dome aeration in mechanical-biological waste treatment. In: Proceedings of the 7th International Waste Management and Landfill Symposium, Cagliari, 4-8 October 1999; Paar, S., Brummack, J., Gemende, B., 1999b. Mechanical-biological waste stabilization by the dome aeration method. Environment Protection Engineering 25 (3/99). Mollekopf, N., Brummack, J., Paar, S., Vorster, K., 2002. Use of the Dome Aeration Technology for biochemical stabilization of waste prior to landfilling. In: Proceedings of the Wastecon 2002, Waste Congress and Exhibition, Durban, South Africa.]. It is a non-reactor open windrow composting process, with the main advantage being that the input material needs no periodic turning. A rotting time of only 3-4 months indicates the high efficiency. Additionally, the low capital/operational costs, low energy inputs and limited plant requirements provide potential for use in aerobic refuse stabilization. The innovation in the DAT process is the passive aeration achieved by thermally driven advection through open windrows caused by temperature differences between the degrading material and the outside environment. This paper investigates the application of Dome Aeration Technology to pine bark composting as part of an integrated waste management strategy. A full-scale field experiment was performed at the Bisasar Road Landfill Site in Durban to assess the influence of climate, waste composition and operational conditions on the process. A test windrow was constructed and measurements of temperature and airflow through the material were taken. The process

  4. BIOVENTING - Groundwater Aeration by Discontinuous Oxygen Gas Pulse Injections

    NASA Astrophysics Data System (ADS)

    Schirmer, M.

    2003-12-01

    Groundwater aeration by discontinuous oxygen gas pulse injections appears to be a promising concept for enhanced natural attenuation of dissolved contaminants that are susceptible for oxygenase enzyme attacks. Oxygen amendments facilitate indigenous microbiota to catabolize groundwater pollutants, such as aromatics, that are considered to be recalcitrant in absence of dissolved oxygen. As a rule, natural attenuation of many pollutants under aerobic conditions is considerably faster than under anaerobic conditions. Thus, enhancing the dissolved oxygen level appears to be worthwhile. In situ aeration of groundwater has been accomplished by air sparging, H2O2-supply, or by utilization of oxygen release compounds. However, continuous aeration of previously anaerobic groundwater is not desirable for several reasons: (a) economic efforts too high, (b) pollutant dislocation towards surface (desired only in air sparging), (c) risk of aquifer clogging (gas clogging, oxidation of ferrous iron, formation of bioslimes). In contrast, discontinuous oxygen gas sparging provides only for periodical groundwater aeration which is followed by microaerobic and suboxic conditions. Microaerobic conditions can prevail spatially (e.g., at plume fringes or within biofilms) or temporarily (e.g., at discontinuous bioventing). They still allow adapted bacteria to transform environmental pollutants to less toxic compounds, e.g., aromatic ring cleavage after dioxygenasis attack. Ring cleavage products, on the other hand, may be degraded more easily by anaerobic consortia than the initial aromatic compounds, making oxygen depletion periods highly intriguing in regard to an initiation of natural attenuation processes at plume fringes. In our work we outline the effect of oxygen depletion conditions on biodegradation of monchlorobenzene (MCB) as they occur subsequently to temporary aeration periods. For microaerobic conditions, relative to the oxygen supply, a stoichiometric transformation of MCB

  5. A two-phase flow model of the stirring of Al-SiC composite melt

    NASA Astrophysics Data System (ADS)

    Bui, R. T.; Ouellet, R.; Kocaefe, D.

    1994-08-01

    A two-phase flow, three-dimensional, steady-state model is developed to study the flow field and volume fraction distribution in a stirred tank used in the processing of silicon carbide-reinforced aluminum composites in the melt state. The aim is to optimize the stirring to obtain a good mixing of SiC particles. The model is based on the general-purpose code PHOENICS. In addition to the liquid-aluminum phase, the SiC particles are treated as a nonviscous second phase. Interphase momentum transfer occurs through a drag force. Sedimentation is simulated by assigning a high viscosity to the second phase and removing the gravity force when particle concentration reaches a critical value. The stirrers' blades impart a momentum on both phases, proportional to their respective volume fractions. A water model is simulated first, followed by the real Al-SiC melt. The study reveals the importance of particle size that affects the drag force applied on the particles and hence their motion and distribution. The model can be used to study the effect on mixing of tank geometry and the stirrers' operation.

  6. 49 CFR 174.63 - Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank car...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank car tanks. 174.63 Section 174.63 Transportation Other....63 Portable tanks, IM portable tanks, IBCs, Large Packagings, cargo tanks, and multi-unit tank...

  7. School-Meals Makeover Stirs the Pot

    ERIC Educational Resources Information Center

    Shah, Nirvi

    2011-01-01

    Proposed new federal rules governing the meals served to school children across the country each weekday are causing a stir among food industry groups, cafeteria managers, parents, and students. The skirmish is over the U.S. Department of Agriculture's efforts, prompted by the recent passage of the Healthy, Hunger-Free Kids Act, to rewrite the…

  8. Friction Stir & Ultrasonic Solid State Joining Magnesium

    SciTech Connect

    Grant, Glenn J.; Hovanski, Yuri; Santella, M. L.

    2009-12-30

    Solid state joining between automotive sheet steel and magnesium alloys was investigated. Both friction stir welding and ultrasonic welding were utilized to study the potential for creating structural bonds between these dissimilar materials. A detailed investigation into the joint characteristics was undertaken including an evaluation of joint strength, microstructure, chemical structures, and alloy formation.

  9. Tank overpressure: An uplifting experience

    SciTech Connect

    Morgenegg, E.E.

    1982-05-01

    One of the most common causes of tank damage is uplift. The paper discusses the sources and magnitude of pressure that causes tank uplift, repairs that can be performed on tanks that have lifted, and the prevention of tank uplift. Discussion and examples given are limited to tanks 70 feet or less in diameter.

  10. Fuel Tank Technology

    DTIC Science & Technology

    1989-11-01

    structures b) - Equal thermic inertia c) - Equal fluid volume d) - Equal pressure variation on both wings at the change of the room temperature - This...individual fuel sections. Each fuel section is further ccmpartmentated by metall tank shear walls and tank floors into three individual fuel cells to...plate Dy a stretch forming process, and the metallic tank floors . The air intake segments extend from one bulkhead to the other, thus reducing assembly

  11. Investigation and Discussion of Techniques for Hypolimnion Aeration/Oxygenation.

    DTIC Science & Technology

    1984-10-01

    limnion and hypolimnion was 0.1 mg/f/day. The inflow assumption was based upon field data; the latter two assumptions were based upon the.. Fontane and...the meta- limnion and hypolimnion. Because the centerlines of the RBRR penstocks -’ are approximately 70 ft below the surface and significant...technic Institute and State University, Blacksburg, Va.-.:..- Fast, A. W., Dorr, V. A., and Rosen, R. J. 1975. "A Submerged Hypo- limnion Aerator

  12. Underground petroleum tanks

    SciTech Connect

    Not Available

    1990-07-01

    This book presents the results of a survey of 46 state underground storage tank program officials. The survey covers: Whether petroleum tank insurance (mandated by the EPA) is available in each state and whether category 3 and 4 owners can obtain it; state programs that help owners meet the financial responsibility and/or technical requirements of such insurance; and lending institutions' attitudes towards providing loans to storage tank owners. A survey of the number and terms of insurance policies offered to tank owners is also presented.

  13. Hanford tanks initiative plan

    SciTech Connect

    McKinney, K.E.

    1997-07-01

    Abstract: The Hanford Tanks Initiative (HTI) is a five-year project resulting from the technical and financial partnership of the U.S. Department of Energy`s Office of Waste Management (EM-30) and Office of Science and Technology Development (EM-50). The HTI project accelerates activities to gain key technical, cost performance, and regulatory information on two high-level waste tanks. The HTI will provide a basis for design and regulatory decisions affecting the remainder of the Tank Waste Remediation System`s tank waste retrieval Program.

  14. Growth of Indigenous Organisms in Aerated Filtrate of Feedlot Waste

    PubMed Central

    Weiner, B. A.; Rhodes, R. A.

    1974-01-01

    Filtrates from feedlot waste were incubated under aerobic conditions to evaluate the availability of nutrients for cell production and to assess the capacity of indigenous flora to produce stabilized effluents. Incubation was carried out in 9-liter aerated jar fermentors. Three-fourths of the organic material and one-third of the nitrogen were taken up in 4 days; 90% utilization of organic material and nitrogen required almost a month. Acid was produced initially, but aerated liquid thereafter rapidly became alkaline. With pH controlled at 7.0, a comparable pattern of carbon utilization occurred, but nitrogen was incompletely used. The numerically dominant organisms in the waste inoculum were almost immediately displaced by an emergent population of a few types of organisms not originally evident. Maximal viable populations of 109 to 3 × 109 cells/ml were obtained in aerated waste liquid within 48 h; subsequently, numbers declined quickly to initial levels. Numbers of fungi, yeasts, and streptomycetes slowly increased but never exceeded their initial concentration by more than tenfold. PMID:4609184

  15. Soil aeration status in a lowland wet grassland

    NASA Astrophysics Data System (ADS)

    Barber, K. R.; Leeds-Harrison, P. B.; Lawson, C. S.; Gowing, D. J. G.

    2004-02-01

    The maintenance or development of plant community diversity in species-rich wet grasslands has been a focus of water management considerations in the UK for the past 20 years. Much attention has been given to the control of water levels in the ditch systems within these wet grassland systems. In this paper we report measurements of aeration status and water-table fluctuation made on a peat soil site at Tadham Moor in Somerset, UK, where water management has focused on the maintenance of wet conditions that often result in flooding in winter and wet soil conditions in the spring and summer. Measurement and modelling of the water-table fluctuation indicates the possibility of variability in the aeration of the root environment and anoxic conditions for much of the winter period and for part of the spring and summer. We have used water content and redox potential measurements to characterize the aeration status of the peat soil. We find that air-filled porosity is related to water-table depth in these situations. Redox potentials in the spring were generally found to be low, implying a reducing condition for nitrate and iron. A significant relationship (p < 0.01) between redox potential and water-table depth exists for data measured at 0.1 m depth, but no relationship could be found for data from 0.4 m depth.

  16. Thermal Stir Welding: A New Solid State Welding Process

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey

    2003-01-01

    Thermal stir welding is a new welding process developed at NASA's Marshall Space Flight Center in Huntsville, AL. Thermal stir welding is similar to friction stir welding in that it joins similar or dissimilar materials without melting the parent material. However, unlike friction stir welding, the heating, stirring and forging elements of the process are all independent of each other and are separately controlled. Furthermore, the heating element of the process can be either a solid-state process (such as a thermal blanket, induction type process, etc), or, a fusion process (YG laser, plasma torch, etc.) The separation of the heating, stirring, forging elements of the process allows more degrees of freedom for greater process control. This paper introduces the mechanics of the thermal stir welding process. In addition, weld mechanical property data is presented for selected alloys as well as metallurgical analysis.

  17. Thermal Stir Welding: A New Solid State Welding Process

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    Thermal stir welding is a new welding process developed at NASA's Marshall Space Flight Center in Huntsville, AL. Thermal stir welding is similar to friction stir welding in that it joins similar or dissimilar materials without melting the parent material. However, unlike friction stir welding, the heating, stirring and forging elements of the process are all independent of each other and are separately controlled. Furthermore, the heating element of the process can be either a solid-state process (such as a thermal blanket, induction type process, etc), or, a fusion process (YG laser, plasma torch, etc.) The separation of the heating, stirring, forging elements of the process allows more degrees of freedom for greater process control. This paper introduces the mechanics of the thermal stir welding process. In addition, weld mechanical property data is presented for selected alloys as well as metallurgical analysis.

  18. Effects of Solution Stirring on Protein Crystal Growth

    NASA Astrophysics Data System (ADS)

    Yaoi, Mari; Aadachi, Hiroaki; Takano, Kazufumi; Matsumura, Hiroyoshi; Inoue, Tsuyoshi; Mori, Yusuke; Sasaki, Takatomo

    2004-05-01

    We report the influence of solution stirring on the growth of hen egg white lysozyme crystals. Solution stirring rate was controlled by varying the rotation speed of a rotary shaker. A range of precipitation agent (sodium chloride) concentrations was also investigated. The time required for crystal nucleation to occur was observed to be much greater in stirred samples than in unstirred samples. Solution stirring resulted in a reduced number of crystals (at sodium chloride concentrations from 6 to 9%). These crystals were larger and of a higher quality. However, the time required for nucleation to occur was reduced by gentle stirring (25 and 50 rpm) in a 12.5% sodium chloride concentration solution, suggesting that stirring can stimulate nucleation. These results indicate that the optimization of solution stirring rates is a useful technique for controlling protein crystal growth.

  19. Data on the mixing of non-Newtonian fluids by a Rushton turbine in a cylindrical tank.

    PubMed

    Khapre, Akhilesh; Munshi, Basudeb

    2016-09-01

    The paper focuses on the data collected from the mixing of shear thinning non-Newtonian fluids in a cylindrical tank by a Rushton turbine. The data presented are obtained by using Computational Fluid Dynamics (CFD) simulation of fluid flow field in the entire tank volume. The CFD validation data for this study is reported in the research article 'Numerical investigation of hydrodynamic behavior of shear thinning fluids in stirred tank' (Khapre and Munshi, 2015) [1]. The tracer injection method is used for the prediction of mixing time and mixing efficiency of a Rushton turbine impeller.

  20. 49 CFR 179.401 - Individual specification requirements applicable to inner tanks for cryogenic liquid tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... to inner tanks for cryogenic liquid tank car tanks. 179.401 Section 179.401 Transportation Other..., DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank... requirements applicable to inner tanks for cryogenic liquid tank car tanks....

  1. 49 CFR 179.401 - Individual specification requirements applicable to inner tanks for cryogenic liquid tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... to inner tanks for cryogenic liquid tank car tanks. 179.401 Section 179.401 Transportation Other..., DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank... requirements applicable to inner tanks for cryogenic liquid tank car tanks....

  2. 49 CFR 179.401 - Individual specification requirements applicable to inner tanks for cryogenic liquid tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... to inner tanks for cryogenic liquid tank car tanks. 179.401 Section 179.401 Transportation Other..., DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank... requirements applicable to inner tanks for cryogenic liquid tank car tanks....

  3. 49 CFR 179.401 - Individual specification requirements applicable to inner tanks for cryogenic liquid tank car tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... to inner tanks for cryogenic liquid tank car tanks. 179.401 Section 179.401 Transportation Other..., DEPARTMENT OF TRANSPORTATION (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank... requirements applicable to inner tanks for cryogenic liquid tank car tanks....

  4. Comparative analysis of mixing distribution in aerobic stirred bioreactor for simulated yeasts and fungus broths.

    PubMed

    Cascaval, Dan; Galaction, Anca-Irina; Turnea, Marius

    2007-01-01

    The study on mixing distribution for an aerobic stirred bioreactor and simulated (solutions of carboxymethylcellulose sodium salt), yeasts (S. cerevisiae) and fungus (P. chrysogenum pellets and free mycelia) broths indicated the significant variation of mixing time on the bioreactor height. The experiments suggested the possibility to reach a uniform mixing in whole bulk of the real broths for a certain value of rotation speed or biomass concentration domain. For S. cerevisiae broths the optimum rotation speed increased to 500 rpm with the biomass accumulation from 40 to 150 g/l d.w. Irrespective of their morphology, for fungus cultures the existence of optimum rotation speed (500 rpm) has been recorded only for biomass concentration below 24 g/l d.w. The influence of aeration rate depends on the apparent viscosity/biomass concentration and on the impellers and sparger positions. By increasing the apparent viscosity for simulated broths, or biomass amount for real broths, the shape of the curves describing the mixing time variation is significantly changed for all the considered positions. The intensification of the aeration induced the increase of mixing time, which reached a maximum value, decreasing then, due to the flooding phenomena. This variation became more pronounced at higher viscosities for simulated broths, at higher yeasts concentration, and at lower pellets or filamentous fungus concentration, respectively. By means of the experimental data and using MATLAB software, some mathematical correlations for mixing time have been proposed for each broth and considered position inside the bioreactor. These equations offer a good agreement with the experiment, the maximum deviation being +/-7.3% for S. cerevisiae broths.

  5. Effect of aeration rate on production of xylitol from corncob hemicellulose hydrolysate.

    PubMed

    Ding, Xinghong; Xia, Liming

    2006-06-01

    The effects of different aeration conditions on xylitol production from corncob hemicellulose hydrolysate by Candida sp. ZU04 were investigated. Batch fermentations were carried out in a 3.7-L fermentor at 30 degrees C, pH 5.5, and agitation of 300 rpm. It was found that the two-phase aeration process was more effective than the one-phase aeration process in xylitol production. In the first 24 h of the aerobic phase, a high aeration rate was applied, glucose was soon consumed, and biomass increased quickly. In the second fermentation phase, aeration rate was reduced and an improved xylitol yield was obtained. The maximum xylitol yield (0.76 g/g) was obtained with an aeration rate of 1.5 vvm (KLa of 37 h-1) for the first 24 h and 0.3 vvm (KLa of 6 h-1) from 24 to 96 h.

  6. External Tank Program - Legacy of Success

    NASA Technical Reports Server (NTRS)

    Pilet, Jeffery C.; Diecidue-Conners, Dawn; Worden, Michelle; Guillot, Michelle; Welzyn, Kenneth

    2011-01-01

    The largest single element of Space Shuttle is the External Tank (ET), which serves as the structural backbone of the vehicle during ascent and provides liquid propellants to the Orbiter s three Main Engines. The ET absorbs most of the seven million pounds of thrust exerted by the Solid Rocket Boosters and Main Engines. The design evolved through several block changes, reducing weight each time. Because the tank flies to orbital velocity with the Space Shuttle Orbiter, minimization of weight is mandatory, to maximize payload performance. The initial configuration, the standard weight tank, weighed 76,000 pounds and was an aluminum 2219 structure. The light weight tank weighed 66,000 pounds and flew 86 missions. The super light weight tank weighed 58,500 pounds and was primarily an aluminum-lithium structure. The final configuration and low weight enabled system level performance sufficient for assembly of the International Space Station in a high inclination orbit, vital for international cooperation. Another significant challenge was the minimization of ice formation on the cryogenic tanks. This was essential due to the system configuration and the choice of ceramic thermal protection system materials on the Orbiter. Ice would have been a major debris hazard. Spray on foam insulation materials served multiple functions including thermal insulation, conditioning of cryogenic propellants, and thermal protection for the tank structure during ascent and entry. The tank is large, and unique manufacturing facilities, tooling, and handling, and transportation operations were developed. Weld processes and tooling evolved with the design as it matured through several block changes. Non Destructive Evaluation methods were used to assure integrity of welds and thermal protection system materials. The aluminum-lithium alloy was used near the end of the program and weld processes and weld repair techniques had to be refined. Development and implementation of friction stir

  7. Underground Tank Management.

    ERIC Educational Resources Information Center

    Bednar, Barbara A.

    1990-01-01

    The harm to human health and our environment caused by leaking underground storage tanks can be devastating. Schools can meet new federal waste management standards by instituting daily inventory monitoring, selecting a reliable volumetric testing company, locating and repairing leaks promptly, and removing and installing tanks appropriately. (MLH)

  8. Oxygen tank assemblies

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Structural design considerations for O2 tank shells and suspension systems of ground based storage and mobile tank systems are outlined. Safety factors, chemical compatibility, liquid slosh strength, and cryogenic temperature properties are summarized. Finally, costs, quality control measures, and long life characteristics are examined.

  9. Rainwater tank drowning.

    PubMed

    Byard, Roger W

    2008-11-01

    Drowning remains a significant cause of accidental death in young children. The site of drowning varies among communities and is influenced by cultural and geographic factors, including the availability of particular water sources. The drowning deaths of a twin two-year-old brother and sister in a rainwater tank are reported to demonstrate specific issues that may arise. Ladders, vegetation and trellises may provide access to tanks and should be removed. Secure child-proof access points should also be installed, particularly on in-ground tanks (given the ready accessibility of the latter). As there has been a recent trend in Australia to install more domestic rainwater tanks, the number of childhood rainwater tank drownings and near-drownings will need to be monitored by forensic pathologists and child death review committees to ensure that this has not led to the introduction of a new hazard into the home environment.

  10. Tank characterization reference guide

    SciTech Connect

    De Lorenzo, D.S.; DiCenso, A.T.; Hiller, D.B.; Johnson, K.W.; Rutherford, J.H.; Smith, D.J.; Simpson, B.C.

    1994-09-01

    Characterization of the Hanford Site high-level waste storage tanks supports safety issue resolution; operations and maintenance requirements; and retrieval, pretreatment, vitrification, and disposal technology development. Technical, historical, and programmatic information about the waste tanks is often scattered among many sources, if it is documented at all. This Tank Characterization Reference Guide, therefore, serves as a common location for much of the generic tank information that is otherwise contained in many documents. The report is intended to be an introduction to the issues and history surrounding the generation, storage, and management of the liquid process wastes, and a presentation of the sampling, analysis, and modeling activities that support the current waste characterization. This report should provide a basis upon which those unfamiliar with the Hanford Site tank farms can start their research.

  11. Stainless steel tanks

    SciTech Connect

    Hagen, T.

    1995-12-31

    There is currently no recognized code or standard for the design, fabrication and construction of atmospheric and low pressure stainless steel tanks. At the present time these tanks are being designed to individual specifications, manufacturers standards or utilizing other codes and standards that may not be entirely applicable. Recognizing the need, the American Petroleum Institute will be publishing a new appendix to the API STD 650 Standard which will cover stainless steel tanks. The new Appendix was put together by a Task Group of selected individuals from the API Subcommittee of Pressure Vessels and Tanks from the Committee on Refinery Equipment. This paper deals with the development and basis of the new appendix. The new appendix will provide a much needed standard to cover the material, design, fabrication, erection and testing requirements for vertical, cylindrical, austenitic stainless steel aboveground tanks in nonrefrigerated service.

  12. Effects of aeration position on organics, nitrogen and phosphorus removal in combined oxidation pond-constructed wetland systems.

    PubMed

    Wang, Xiaoou; Tian, Yimei; Zhao, Xinhua; Peng, Sen; Wu, Qing; Yan, Lijian

    2015-12-01

    Given that few studies investigated the effects of aeration position (AP) on the performance of aerated constructed wetlands, the aim of this study was to evaluate the effects of AP on organics, nitrogen and phosphorus removal in lab-scale combined oxidation pond-constructed wetland (OP-CW) systems. Results showed that middle aeration allowed the CW to possess more uniform oxygen distribution and to achieve greater removals of COD and NH3-N, while the CW under bottom aeration and surface aeration demonstrated more distinct stratification of oxygen distribution and surface aeration brought about better TN removal capacity for the OP-CW system. However, no significant influence of artificial aeration or AP on TP removal was observed. Overall, AP could significantly affect the spatial distribution of dissolved oxygen by influencing the oxygen diffusion paths in aerated CWs, thereby influencing the removal of pollutants, especially organics and nitrogen, which offers a reference for the design of aerated CWs.

  13. Prototype Evaluation of Sluiceway Aeration System Libby Dam, Kootenai River, Montana.

    DTIC Science & Technology

    1984-03-01

    during an emergency gate lowering operation.- Results of the data reduction indicated a virtual elimination of the cavitation-inducing negative... virtually been eliminated. the following tabulation lists The comparative data given in Plates 17 (without aerator) and 18 (with aerator, Series A). Sluice...pressures on the center sluice invert have been virtually eliminated with the introduction of the aerator. All calculated cavitation indices are

  14. Spray Structure in Near-Injector Region of Aerated Jet in Subsonic Crossflow (Postprint)

    DTIC Science & Technology

    2009-04-01

    diameter by introducing gas bubbles into the liquid stream inside the injector. Aerated injection is similar to the flash atomization because it...produces gas bubbles inside the injector for promoting atomization. However, unlike flash atomizers, aerated injection can easily control the amount of... bubbles and their sizes without the complications of dissolving gas or heating the liquid to its boiling point. The aerated liquid injector allows a

  15. EFFECT OF FLOW CHARACTERISTICS ON DO DISTRIBUTION IN A FULL SCALE OXIDATION DITCH WITH DIFFUSED AERATION AND VERTICAL FLOW BOOSTERS

    NASA Astrophysics Data System (ADS)

    Nakamachi, Kazuo; Fujiwara, Taku; Kawaguchi, Yukio; Tsuno, Hiroshi

    The high loading rate oxidation ditch (OD) system with dual dissolved oxygen (DO) control has been developed for the purpose of advanced wastewater treatment and cost saving. For the purpose of scale-up to the real scale, the clean water experiments were conducted, with the full scale oxidation ditch with diffused aeration and vertical flow boosters, to examine the effect to the dual DO control by the design and operational factors, which include a flow characteristics and a oxygen supply capability. In this study, the flow characteristics of the OD channel were analyzed using a tank number and circulation ratio as the parameters. The analysis showed the complicated flow characteristics of the OD channel, which changed from the plug flow to the completely mixing transiently. Based on the tank number N =65~100 which were obtained from the tracer tests, a model of DO mass balance was constructed, then the accurate method for estimate the overall oxygen transfer coefficients was proposed. The potential error of the conventional method in the specific conditions was indicated. In addition, the effect of the flow characteristics on the design and operational parameters of the dual DO control, which include the circulation time or the DO profile, was clarified.

  16. 49 CFR 179.201 - Individual specification requirements applicable to non-pressure tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... to non-pressure tank car tanks. 179.201 Section 179.201 Transportation Other Regulations Relating to... MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes... car tanks....

  17. Friction stir processing on carbon steel

    SciTech Connect

    Tarasov, Sergei Yu.; Melnikov, Alexander G.; Rubtsov, Valery E.

    2014-11-14

    Friction stir processing of medium carbon steel samples has been carried out using a milling machine and tools made of cemented tungsten carbide. Samples have been machined from 40 and 40X steels. The tools have been made in the shape of 5×5×1.5 mm and 3×3×1.5 mm tetrahedrons. The microstructure of stirred zone has been obtained using the smaller tool and consists of fine recrystallized 2-3 μm grains, whereas the larger tool has produced the 'onion-like' structures comprising hard quenched 'white' 500-600 MPa layers with 300-350 MPa interlayers of bainite needles. The mean values of wear intensity obtained after measuring the wear scar width were 0.02 mm/m and 0.001 mm/m for non-processed and processed samples, respectively.

  18. Numerical Modeling of Mixing of Chemically Reacting, Non-Newtonian Slurry for Tank Waste Retrieval

    SciTech Connect

    Yuen, David A.; Onishi, Yasuo; Rustad, James R.; Michener, Thomas E.; Felmy, Andrew R.; Ten, Arkady A.; Hier, Catherine A.

    2000-06-01

    Many highly radioactive wastes will be retrieved by installing mixer pumps that inject high-speed jets to stir up the sludge, saltcake, and supernatant liquid in the tank, blending them into a slurry. This slurry will then be pumped out of the tank into a waste treatment facility. Our objectives are to investigate interactions-chemical reactions, waste rheology, and slurry mixing-occurring during the retrieval operation and to provide a scientific basis for the waste retrieval decision-making process. Specific objectives are to: (1) Evaluate numerical modeling of chemically active, non-Newtonian tank waste mixing, coupled with chemical reactions and realistic rheology; (2) Conduct numerical modeling analysis of local and global mixing of non-Newtonian and Newtonian slurries; and (3) Provide the bases to develop a scientifically justifiable, decision-making support tool for the tank waste retrieval operation.

  19. Fe-As sludge stability and effluent quality for a two-stage As-contaminated water treatment with Fe(II) and aeration.

    PubMed

    Zhuang, J Ming; Hobenshield, Evan; Walsh, Tony

    2009-02-01

    A two-stage (I and II) lab-scale treatment system has been studied for arsenic removal from water using Fe(II) and lignosulphonates with aeration. In stage I, using an Fe/As mole ratio of 1.5-2.5 at a pH of around 6.5-7.5, the dissolved arsenic can be reduced with Fe(II) oxidation-precipitation from an initial 72 mg L(-1) to < 2 mg L(-1). The generated sludge is entirely recycled to the second tank of stage II. In the first tank of stage II, the water is further treated with the same amount of Fe(II) as that used in stage I, in the presence of lignosulphonates and aeration. The air-oxidization of Fe(II) to Fe(III) is continued for about 30 minutes at a pH of around 7.0-8.0. The water output from the first tank is transferred to the second tank in which mixing under aeration occurs with the sludge recycled from stage I. Accordingly, the dissolved arsenic in the effluent is reduced to < 0.1 mg L(-1). The results show that this two-stage process can save more than 50% of total chemical costs, and reduce the amount of sludge by more than 50%, in comparison with the conventional Fe(III)/lime-treatment process. According to US EPA regulations, the final Fe-As sludge is classified as non-hazardous materials by the Toxicity Characteristic Leaching Procedure. But, the study shows that the instability of Fe-As sludge could be influenced by some factors, such as higher pH levels, a longer water-leaching time and larger water-leaching volume, leading to the liberation of more dissolvable As species. After being treated with Ligmet stabilizer, the Fe-As sludge showed an improved stability under varying pH conditions and large amounts of water leaching. The treated Fe-As sludge is suitable for landfill disposal.

  20. Microstructure characterization of the stir zone of submerged friction stir processed aluminum alloy 2219

    SciTech Connect

    Feng, Xiuli; Liu, Huijie; Lippold, John C.

    2013-08-15

    Aluminum alloy 2219-T6 was friction stir processed using a novel submerged processing technique to facilitate cooling. Processing was conducted at a constant tool traverse speed of 200 mm/min and spindle rotation speeds in the range from 600 to 800 rpm. The microstructural characteristics of the base metal and processed zone, including grain structure and precipitation behavior, were studied using optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Microhardness maps were constructed on polished cross sections of as-processed samples. The effect of tool rotation speed on the microstructure and hardness of the stir zone was investigated. The average grain size of the stir zone was much smaller than that of the base metal, but the hardness was also lower due to the formation of equilibrium θ precipitates from the base metal θ′ precipitates. Stir zone hardness was found to decrease with increasing rotation speed (heat input). The effect of processing conditions on strength (hardness) was rationalized based on the competition between grain refinement strengthening and softening due to precipitate overaging. - Highlights: • SZ grain size (∼ 1 μm) is reduced by over one order of magnitude relative to the BM. • Hardness in the SZ is lower than that of the precipitation strengthened BM. • Metastable θ′ in the base metal transforms to equilibrium θ in the stir zone. • Softening in the SZ results from a decrease of precipitation strengthening.

  1. An Eco-tank system containing microbes and different aquatic plant species for the bioremediation of N,N-dimethylformamide polluted river waters.

    PubMed

    Xiao, Jibo; Chu, Shuyi; Tian, Guangming; Thring, Ronald W; Cui, Lingzhou

    2016-12-15

    An Eco-tank system of 10m was designed to simulate the natural river. It consisted of five tanks sequentially connected containing microbes, biofilm carriers and four species of floating aquatic plants. The purification performance of the system for N,N-dimethylformamide (DMF) polluted river water was evaluated by operating in continuous mode. DMF was completely removed in Tanks 1 and 2 at influent DMF concentrations between 75.42 and 161.05mg L(-1). The NH4(+)-N concentration increased in Tank 1, followed by a gradual decrease in Tanks 2-5. Removal of NH4(+)-N was enhanced by aeration. The average effluent NH4(+)-N concentration of Tank 5 decreased to a minimum of 0.89mg L(-1), corresponding to a decrease of 84.8% when compared with that before aeration. TN concentration did not decrease significantly as expected after inoculation with denitrifying bacteria. The average effluent TN concentration of the system was determined to be 4.58mg L(-1), still unable to satisfy the Class V standard for surface water environmental quality. The results of this study demonstrated that the Eco-tank system is an efficient process in removing DMF, TOC, and NH4(+)-N from DMF polluted river water. However, if possible, alternative technologies should be adopted for controlling the effluent TN concentration.

  2. Fuel property effects in stirred combustors

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Soot formation in strongly backmixed combustion was investigated using the jet-stirred combustor (JSC). This device provided a combustion volume in which temperature and combustion were uniform. It simulated the recirculating characteristics of the gas turbine primary zone; it was in this zone where mixture conditions were sufficiently rich to produce soot. Results indicate that the JSC allows study of soot formation in an aerodynamic situation revelant to gas turbines.

  3. Magnesium Based Composite via Friction Stir Processing

    DTIC Science & Technology

    2013-04-01

    process developed by Mishra et.al [8] based on the principles of friction stir welding ( FSW ) is getting increased attention. It involves the traverse...compared to other thermomechanical processes [9]. Mishra et al. [10] have used FSP to fabricate a surface composite with SiC particulates in aluminum ...This work was followed by other reports of composite fabrication in aluminum alloys with various reinforcements, like Al3Ti, Al2Cu, Al2O3

  4. Flexible Hybrid Friction Stir Joining Technology

    SciTech Connect

    2008-12-01

    This factsheet describes a research project whose goal is to advance the friction stir welding (FSW) process as a manufacturing technology that can be deployed for on-site construction of large, complex and typically thick-sectioned structures made of high performance and high-temperature materials. This would transform FSW from a specialty joining process into one with pervasive application potential across a number of industrial sectors where the payoff of energy reduction, environmental and economic benefits would be significant.

  5. Ultrasonic stir welding process and apparatus

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey (Inventor)

    2009-01-01

    An ultrasonic stir welding device provides a method and apparatus for elevating the temperature of a work piece utilizing at least one ultrasonic heater. Instead of relying on a rotating shoulder to provide heat to a workpiece an ultrasonic heater is utilized to provide ultrasonic energy to the workpiece. A rotating pin driven by a motor assembly performs the weld on the workpiece. A handheld version can be constructed as well as a fixedly mounted embodiment.

  6. Landfill aeration in the framework of a reclamation project in Northern Italy.

    PubMed

    Raga, Roberto; Cossu, Raffaello

    2014-03-01

    In situ aeration by means of the Airflow technology was proposed for landfill conditioning before landfill mining in the framework of a reclamation project in Northern Italy. A 1-year aeration project was carried out on part of the landfill with the objective of evaluating the effectiveness of the Airflow technology for landfill aerobization, the evolution of waste biological stability during aeration and the effects on leachate and biogas quality and emissions. The main outcomes of the 1-year aeration project are presented in the paper. The beneficial effect of the aeration on waste biological stability was clear (63% reduction of the respiration index); however, the effectiveness of aeration on the lower part of the landfill is questionable, due to the limited potential for air migration into the leachate saturated layers. During the 1-year in situ aeration project approx. 275 MgC were discharged from the landfill body with the extracted gas, corresponding to 4.6 gC/kgDM. However, due to the presence of anaerobic niches in the aerated landfill, approx. 46% of this amount was extracted as CH4, which is higher than reported in other aeration projects. The O2 conversion quota was lower than reported in other similar projects, mainly due to the higher air flow rates applied. The results obtained enabled valuable recommendations to be made for the subsequent application of the Airflow technology to the whole landfill.

  7. Bioreactor tests preliminary to landfill in situ aeration: A case study

    SciTech Connect

    Raga, Roberto; Cossu, Raffaello

    2013-04-15

    Highlights: ► Carbon and nitrogen mass balances in aerated landfill simulation reactors. ► Waste stabilization in aerated landfill simulation reactors. ► Effect of temperature on biodegradation processes in aerated landfills. - Abstract: Lab scale tests in bioreactor were carried out in the framework of the characterization studies of a landfill where in situ aeration (possibly followed by landfill mining) had been proposed as part of the novel waste management strategy in a region in northern Italy. The tests were run to monitor the effects produced by aerobic conditions at different temperatures on waste sampled at different depths in the landfill, with focus on the carbon and nitrogen conversion during aeration. Temperatures ranging from 35 to 45 °C were chosen, in order to evaluate possible inhibition of biodegradation processes (namely nitrification) at 45 °C in the landfill. The results obtained showed positive effects of the aeration on leachate quality and a significant reduction of waste biodegradability. Although a delay of biodegradation processes was observed in the reactor run at 45 °C, biodegradation rates increased after 2 months of aeration, providing very low values of the relevant parameters (as in the other aerated reactors) by the end of the study. Mass balances were carried out for TOC and N-NH{sub 4}{sup +}; the findings obtained were encouraging and provided evidence of the effectiveness of carbon and nitrogen conversion processes in the aerated landfill simulation reactors.

  8. Method and apparatus for energy efficient self-aeration in chemical, biochemical, and wastewater treatment processes

    DOEpatents

    Gao, Johnway [Richland, WA; Skeen, Rodney S [Pendleton, OR

    2002-05-28

    The present invention is a pulse spilling self-aerator (PSSA) that has the potential to greatly lower the installation, operation, and maintenance cost associated with aerating and mixing aqueous solutions. Currently, large quantities of low-pressure air are required in aeration systems to support many biochemical production processes and wastewater treatment plants. Oxygen is traditionally supplied and mixed by a compressor or blower and a mechanical agitator. These systems have high-energy requirements and high installation and maintenance costs. The PSSA provides a mixing and aeration capability that can increase operational efficiency and reduce overall cost.

  9. Improvement of oxygen transfer efficiency in aerated ponds using liquid-film-assisted approach.

    PubMed

    Zhu, H; Imai, T; Tani, K; Ukita, M; Sekine, M; Higuchi, T; Zhang, Z

    2007-01-01

    In aerated ponds, oxygen is generally supplied through either diffused or mechanical aeration means. Surface transfer and bubble transfer both contribute significantly to oxygen transfer in a diffused aeration system. In the present study, a liquid-film-forming apparatus (LFFA) is successfully developed on a laboratory scale to improve considerably the surface transfer via the unique liquid film transfer technique. The experimental results show that the volumetric mass transfer coefficient for LFFA alone is found to be as much as 5.3 times higher than that for water surface and that the total volumetric mass transfer coefficient for the liquid film aeration system increases by 37% in comparison with a conventional aeration system. Additionally, by tuning finely the structural parameters of the LFFA, it can also lead to high dissolved oxygen (DO) water with the DO percent saturation greater than 90%. More importantly, this result is accomplished by simply offering a single-pass aeration at a depth as shallow as 26 cm. As a result, the objective of economical energy consumption in aerated ponds can be realized by lowering the aeration depth without sacrificing the aeration efficiency. It is noteworthy that the data presented in this study are acquired either numerically or experimentally.

  10. Partial nitritation ANAMMOX in submerged attached growth bioreactors with smart aeration at 20 °C.

    PubMed

    Shannon, James M; Hauser, Lee W; Liu, Xikun; Parkin, Gene F; Mattes, Timothy E; Just, Craig L

    2015-01-01

    Submerged attached growth bioreactors (SAGBs) were operated at 20 °C for 30 weeks in smart-aerated, partial nitritation ANAMMOX mode and in a timer-controlled, cyclic aeration mode. The smart-aerated SAGBs removed 48-53% of total nitrogen (TN) compared to 45% for SAGBs with timed aeration. Low dissolved oxygen concentrations and cyclic pH patterns in the smart-aerated SAGBs suggested conditions favorable to partial nitritation ANAMMOX and stoichiometrically-derived and numerically modeled estimations attributed 63-68% and 14-44% of TN removal to partial nitritation ANAMMOX in these bioreactors, respectively. Ammonia removals of 36-67% in the smart-aerated SAGBs, with measured oxygen and organic carbon limitations, further suggest partial nitritation ANAMMOX. The smart-aerated SAGBs required substantially less aeration to achieve TN removals similar to SAGBs with timer-controlled aeration. Genomic DNA testing confirmed that the dominant ANAMMOX seed bacteria, received from a treatment plant utilizing the DEMON® sidestream deammonification process, was a Candidatus Brocadia sp. (of the Planctomycetales order). The DNA from these bacteria was also present in the SAGBs at the conclusion of the study providing evidence for attached growth and limited biomass washout.

  11. Effect of influent aeration on removal of organic matter from coffee processing wastewater in constructed wetlands.

    PubMed

    Rossmann, Maike; Matos, Antonio Teixeira; Abreu, Edgar Carneiro; Silva, Fabyano Fonseca; Borges, Alisson Carraro

    2013-10-15

    The aim of the present study was to evaluate the influence of aeration and vegetation on the removal of organic matter in coffee processing wastewater (CPW) treated in 4 constructed wetlands (CWs), characterized as follows: (i) ryegrass (Lolium multiflorum) cultivated system operating with an aerated influent; (ii) non-cultivated system operating with an aerated influent, (iii) ryegrass cultivated system operating with a non-aerated influent; and (iv) non-cultivated system operating with a non-aerated influent. The lowest average chemical oxygen demand (COD), biochemical oxygen demand (BOD) and total suspended solids (TSS) removal efficiencies of 87, 84 and 73%, respectively, were obtained in the ryegrass cultivated system operating with a non-aerated influent. However, ryegrass cultivation did not influence the removal efficiency of organic matter. Artificial aeration of the CPW, prior to its injection in the CW, did not improve the removal efficiencies of organic matter. On other hand it did contribute to increase the instantaneous rate at which the maximum COD removal efficiency was reached. Although aeration did not result in greater organic matter removal efficiencies, it is important to consider the benefits of aeration on the removal of the other compounds.

  12. Stir bar sorptive extraction for trace analysis.

    PubMed

    David, Frank; Sandra, Pat

    2007-06-08

    Stir bar sorptive extraction (SBSE) was introduced in 1999 as a solventless sample preparation method for the extraction and enrichment of organic compounds from aqueous matrices. The method is based on sorptive extraction, whereby the solutes are extracted into a polymer coating on a magnetic stirring rod. The extraction is controlled by the partitioning coefficient of the solutes between the polymer coating and the sample matrix and by the phase ratio between the polymer coating and the sample volume. For a polydimethylsiloxane coating and aqueous samples, this partitioning coefficient resembles the octanol-water partitioning coefficient. In comparison to solid phase micro-extraction, a larger amount of sorptive extraction phase is used and consequently extremely high sensitivities can be obtained as illustrated by several successful applications in trace analysis in environmental, food and biomedical fields. Initially SBSE was mostly used for the extraction of compounds from aqueous matrices. The technique has also been applied in headspace mode for liquid and solid samples and in passive air sampling mode. In this review article, the principles of stir bar sorptive extraction are described and an overview of SBSE applications is given.

  13. Tank 241-U-202 tank characterization plan

    SciTech Connect

    Schreiber, R.D.

    1995-02-21

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 222-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-U-202.

  14. Tank 241-U-201 tank characterization plan

    SciTech Connect

    Schreiber, R.D.

    1995-02-21

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 22-S Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of samples for tank 241-U-201.

  15. ADM. Tanks: from left to right: fuel oil tank, fuel ...

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

    ADM. Tanks: from left to right: fuel oil tank, fuel pump house (TAN-611), engine fuel tank, water pump house, water storage tank. Camera facing northwest. Not edge of shielding berm at left of view. Date: November 25, 1953. INEEL negative no. 9217 - Idaho National Engineering Laboratory, Test Area North, Scoville, Butte County, ID

  16. Continuous tank reactors in series: an improved alternative in the removal of phenolic compounds with immobilized peroxidase.

    PubMed

    Gómez, E; Máximo, M F; Montiel, M C; Gómez, M; Murcia, M D; Ortega, S

    2012-01-01

    Immobilized derivatives of soybean peroxidase, covalently bound to a glass support, were used in a continuous stirred tank reactor in series, in order to study the removal of two phenolic compounds: phenol and 4-chlorophenol. The use of two reactors in series, rather than one continuous tank, improved the removal efficiencies of phenol and 4-chlorophenol. The distribution of different amounts of enzyme between the two tanks showed that the relative distributions influenced the removal efficiency reached and the degree of the enzyme deactivation. The highest removal percentages were reached at the outlet of the second tank for a distribution of 50% of the enzyme in each tank. However, with a distribution of 75% in the first tank and 25% in the second, the elimination percentage in the second tank was slightly lower than in the previous case, and the effects of deactivation of the enzyme in the first tank were less pronounced. In all the distributions assayed it was observed that the first tank acts as a filter for the second one, which receives a feed with a smaller load of phenolic compounds, thus diminishing enzyme deactivation in the second tank.

  17. Pressurizer tank upper support

    DOEpatents

    Baker, Tod H.; Ott, Howard L.

    1994-01-01

    A pressurizer tank in a pressurized water nuclear reactor is mounted between structural walls of the reactor on a substructure of the reactor, the tank extending upwardly from the substructure. For bearing lateral loads such as seismic shocks, a girder substantially encircles the pressurizer tank at a space above the substructure and is coupled to the structural walls via opposed sway struts. Each sway strut is attached at one end to the girder and at an opposite end to one of the structural walls, and the sway struts are oriented substantially horizontally in pairs aligned substantially along tangents to the wall of the circular tank. Preferably, eight sway struts attach to the girder at 90.degree. intervals. A compartment encloses the pressurizer tank and forms the structural wall. The sway struts attach to corners of the compartment for maximum stiffness and load bearing capacity. A valve support frame carrying the relief/discharge piping and valves of an automatic depressurization arrangement is fixed to the girder, whereby lateral loads on the relief/discharge piping are coupled directly to the compartment rather than through any portion of the pressurizer tank. Thermal insulation for the valve support frame prevents thermal loading of the piping and valves. The girder is shimmed to define a gap for reducing thermal transfer, and the girder is free to move vertically relative to the compartment walls, for accommodating dimensional variation of the pressurizer tank with changes in temperature and pressure.

  18. Pressurizer tank upper support

    DOEpatents

    Baker, T.H.; Ott, H.L.

    1994-01-11

    A pressurizer tank in a pressurized water nuclear reactor is mounted between structural walls of the reactor on a substructure of the reactor, the tank extending upwardly from the substructure. For bearing lateral loads such as seismic shocks, a girder substantially encircles the pressurizer tank at a space above the substructure and is coupled to the structural walls via opposed sway struts. Each sway strut is attached at one end to the girder and at an opposite end to one of the structural walls, and the sway struts are oriented substantially horizontally in pairs aligned substantially along tangents to the wall of the circular tank. Preferably, eight sway struts attach to the girder at 90[degree] intervals. A compartment encloses the pressurizer tank and forms the structural wall. The sway struts attach to corners of the compartment for maximum stiffness and load bearing capacity. A valve support frame carrying the relief/discharge piping and valves of an automatic depressurization arrangement is fixed to the girder, whereby lateral loads on the relief/discharge piping are coupled directly to the compartment rather than through any portion of the pressurizer tank. Thermal insulation for the valve support frame prevents thermal loading of the piping and valves. The girder is shimmed to define a gap for reducing thermal transfer, and the girder is free to move vertically relative to the compartment walls, for accommodating dimensional variation of the pressurizer tank with changes in temperature and pressure. 10 figures.

  19. [Biological phosphorus removal in intermittent aerated biological filter].

    PubMed

    Zeng, Long-Yun; Yang, Chun-Ping; Guo, Jun-Yuan; Luo, Sheng-Lian

    2012-01-01

    Under intermittent aerated and continuous fed operation where the biofilm system was subjected to alternated anaerobic/aerobic condition, the effect of influent volatile fatty acids (VFAs) concentrations, operation cycle and backwash on the biological phosphorus removal performance of the biofilter was studied. In the experiment, synthetic domestic wastewater was used, and the influent velocity was 5 L x h(-1) with gas versus liquid ratio of 8:1 and hydraulic retention time (HRT) of 1.3 h, resulting in average COD, ammonium and phosphorus load of 4.7, 0.41 and 0.095 g x (L x d) (-1) respectively. Results show that, (1) effective release and uptake of phosphorus was achieved in a operation cycle; (2) when influent VFAs was 100 mg x L(-1) (calculated by COD value) and operation cycle was 6 h the filter performed best in phosphorus removal, the phosphorus loading removal rate can be as much as 0.059 g x (L x d)(-1) at the aerated phase with those of COD and ammonium being 3.8 g x (L x d)(-1) and 0.28 g x (L x d)(-1) respectively, and with average effluent phosphorus, COD and ammonium concentrations being 1.8, 43.6 and 8.7 mg x L(-1), which shows nitrogen loss also happened; (3) the pause of backwash decreased the phosphorus removal performance rapidly with the removal efficiency lower than 40% in two days, but the consequent daily backwash operation gave a short improvement on the phosphorus removal, which disappeared in another two days. Thus, it is shown that biological phosphorus removal achieved with better phosphorus loading removal performance in the biofilter under intermittent aerated and continuous fed operation, and that sufficient and stable influent VFAs concentration, proper operation cycle, and more frequent backwash favored the performance.

  20. Pseudomonads Rule Degradation of Polyaromatic Hydrocarbons in Aerated Sediment

    PubMed Central

    Wald, Jiri; Hroudova, Miluse; Jansa, Jan; Vrchotova, Blanka; Macek, Tomas; Uhlik, Ondrej

    2015-01-01

    Given that the degradation of aromatic pollutants in anaerobic environments such as sediment is generally very slow, aeration could be an efficient bioremediation option. Using stable isotope probing (SIP) coupled with pyrosequencing analysis of 16S rRNA genes, we identified naphthalene-utilizing populations in aerated polyaromatic hydrocarbon (PAH)-polluted sediment. The results showed that naphthalene was metabolized at both 10 and 20°C following oxygen delivery, with increased degradation at 20°C as compared to 10°C—a temperature more similar to that found in situ. Naphthalene-derived 13C was primarily assimilated by pseudomonads. Additionally, Stenotrophomonas, Acidovorax, Comamonas, and other minor taxa were determined to incorporate 13C throughout the measured time course. The majority of SIP-detected bacteria were also isolated in pure cultures, which facilitated more reliable identification of naphthalene-utilizing populations as well as proper differentiation between primary consumers and cross-feeders. The pseudomonads acquiring the majority of carbon were identified as Pseudomonas veronii and Pseudomonas gessardii. Stenotrophomonads and Acidovorax defluvii, however, were identified as cross-feeders unable to directly utilize naphthalene as a growth substrate. PAH degradation assays with the isolated bacteria revealed that all pseudomonads as well as Comamonas testosteroni degraded acenaphthene, fluorene, and phenanthrene in addition to naphthalene. Furthermore, P. veronii and C. testosteroni were capable of transforming anthracene, fluoranthene, and pyrene. Screening of isolates for naphthalene dioxygenase genes using a set of in-house designed primers for Gram-negative bacteria revealed the presence of such genes in pseudomonads and C. testosteroni. Overall, our results indicated an apparent dominance of pseudomonads in the sequestration of carbon from naphthalene and potential degradation of other PAHs upon aeration of the sediment at both 20 and

  1. Quick-start of full-scale anaerobic digestion (AD) using aeration

    SciTech Connect

    Lagerkvist, Anders Pelkonen, Markku; Wikström, Tommy

    2015-04-15

    Highlights: • A fast, and original, start up procedure for anaerobic digestors has been applied at full scale. • The development of a methanogenic culture has been documented using fluorescent in situ hybridization. • The technique can be widely applied. - Abstract: A conventional 1300 m{sup 3} continuously stirred anaerobic tank reactor at the city of Boden, north Sweden, which was receiving a feed of both sewage sludge and food waste, was put out of operation due to the build-up of a float phase. The reactor was emptied and cleaned. At start-up there was no methanogenic sludge available, so an unconventional start-up procedure was applied: The reactor was rapidly (8 days with 1200 kg of total solids (TS) added daily) filled with thickened, and slightly acidic sewage sludge, showing only slight methane generation, which was subsequently heated to 55 °C. Then compressed air was blown into the digester and within a month a fully functional methanogenic culture was established. The transfer from acidogenic to methanogenic conditions happened in about one week. As a start-up technique this is fast and cost efficient, it only requires the access of a compressor, electricity and a source of air. In total, about 16 tonnes of oxygen were used. It is proposed that this method may also be used as an operational amendment technique, should a reactor tend to acidify.

  2. Stirring effects in models of oceanic plankton populations

    NASA Astrophysics Data System (ADS)

    Neufeld, Zoltan

    2012-09-01

    We present an overview and extend previous results on the effects of large scale oceanic transport processes on plankton population dynamics, considering different types of ecosystem models. We find that increasing stirring rate in an environment where the carrying capacity is non-uniformly distributed leads to an overall decrease of the effective carrying capacity of the system. This may lead to sharp regime shifts induced by stirring in systems with multiple steady states. In prey-predator type systems, stirring leads to resonant response of the population dynamics to fluctuations enhancing the spatial variability—patchiness—in a certain range of stirring rates. Oscillatory population models produce strongly heterogeneous patchy distribution of plankton blooms when the stirring is weak, while strong stirring may either synchronise the oscillatory dynamics, when the inhomogeneity is relatively weak, or suppress oscillations completely (oscillator death) by reducing the effective carrying capacity below the bifurcation point.

  3. Stirring effects in models of oceanic plankton populations.

    PubMed

    Neufeld, Zoltan

    2012-09-01

    We present an overview and extend previous results on the effects of large scale oceanic transport processes on plankton population dynamics, considering different types of ecosystem models. We find that increasing stirring rate in an environment where the carrying capacity is non-uniformly distributed leads to an overall decrease of the effective carrying capacity of the system. This may lead to sharp regime shifts induced by stirring in systems with multiple steady states. In prey-predator type systems, stirring leads to resonant response of the population dynamics to fluctuations enhancing the spatial variability-patchiness-in a certain range of stirring rates. Oscillatory population models produce strongly heterogeneous patchy distribution of plankton blooms when the stirring is weak, while strong stirring may either synchronise the oscillatory dynamics, when the inhomogeneity is relatively weak, or suppress oscillations completely (oscillator death) by reducing the effective carrying capacity below the bifurcation point.

  4. Pulverizing aeration as a method of lakes restoration

    NASA Astrophysics Data System (ADS)

    Kaczorowska, E.; Podsiadłowski, S.

    2012-04-01

    The principal threat to lakes of the temperate zone is posed by factors accelerating their eutrophication and causing marked deoxygenation of the deeper layers of water, mainly the hypo- and metalimnion. Among their effects are frequent phytoplankton blooms, including those of blue-green algae, and general deterioration of water quality also affecting the abundance and health status of fish. The chief concern is a disturbed proportion between the amount of complex chemical compounds, especially organic, and the oxygen content of lake waters. Natural processes of water oxygenation are not too intensive, because they are practically limited to the epilimnion layer, connected as they are with the activity of aquatic plants of the littoral and sublittoral zone (which tends to disappear in contaminated lakes) and wind energy (the effect of waving). In summer conditions, with a relatively great chemical activity of bottom deposits, the intensity of those processes is usually inadequate. Hence, in 1995 a research was launched in the Institute of Agricultural Engineering of the Agricultural University in Poznań on an integrated lake restoration technology whose core was a self-powered aerator capable of oxygenating also the bottom layers of water (the hypolimnion) of deep lakes. The aerator uses energy obtained from a Savonius rotor mainly to diffuse gases: to release hydrogen sulphide, which usually saturates the hypolimnion water completely, and then to saturate this water with oxygen. Even early studies showed the constructed device to be highly efficient in improving oxygen conditions in the bottom zone. They also made it clear that it should be equipped with an autonomous system designed to inactivate phosphorus, one of the principal factors determining the rate of lake degradation. In 2003 the first wind-driven pulverising aerator equipped with such a system was installed in Town Lake in Chodzież. The aim of this work is to present the principles of operation of a

  5. In situ aeration: Air sparging, bioventing, and related remediation process

    SciTech Connect

    Hinchee, R.E.; Miller, R.N.; Johnson, P.C.

    1995-12-31

    This volume is part of a ten volume set of papers derived from the Third International In Situ and On-Site Bioreclamation Symposium which was held in San Diego, California, in April 1995. The purpose of the conference was to provide a multidisciplinary forum for exchange of state-of-the-art information on bioremediation. This volume focuses on the use of air sparging, bioventing, and other aeration processes to remediate hydrocarbon-contaminated soils and groundwater. Individual papers have been processed separately for inclusion in the appropriate data bases.

  6. Influence of aeration implements, phosphorus fertilizers, and soil taxa on phosphorus losses from grasslands.

    PubMed

    Franklin, D H; Butler, D M; Cabrera, M L; Calvert, V H; West, L T; Rema, J A

    2011-01-01

    Attenuation of rainfall within the solum may help to move contaminants and nutrients into the soil to be better sequestered or utilized by crops. Surface application of phosphorus (P) amendments to grasslands may lead to elevated concentrations of P in surface runoff and eutrophication of surface waters. Aeration of grasslands has been proposed as a treatment to reduce losses of applied P. Here, results from two small-plot aeration studies and two field-scale, paired-watershed studies are supplemented with previously unpublished soil P data and synthesized. The overall objective of these studies was to determine the impact of aeration on soil P, runoff volume, and runoff P losses from mixed tall fescue [Lolium arundinaceum (Schreb.) Darbysh.]-bermudagrass (Cynodon dactylon L.) grasslands fertilized with P. Small-scale rainfall simulations were conducted on two soil taxa using three types of aeration implements: spikes, disks, and cores. The-field scale study was conducted on four soil taxa with slit and knife aeration. Small-plot studies showed that core aeration reduced loads of total P and dissolved reactive P (DRP) in runoff from plots fertilized with broiler litter and that aeration was effective in reducing P export when it increased soil P in the upper 5 cm. In the field-scale study, slit aeration reduced DRP losses by 35% in fields with well-drained soils but not in poorly drained soils. Flow-weighted concentrations of DRP in aerated fields were related to water-soluble P applied in amendments and soil test P in the upper 5 cm. These studies show that the overall effectiveness of mechanical soil aeration on runoff volume and P losses is controlled by the interaction of soil characteristics such as internal drainage and compaction, soil P, type of surface-applied manure, and type of aeration implement.

  7. Corrosion Behavior of Friction Stir Welded High Strength Aluminum Alloys

    DTIC Science & Technology

    2002-01-18

    Angelo Guinasso, " Stress Corrosion Susceptibility in 7050 -T751 Aluminum Following Friction Stir Welding", Proc. First Friction Stir Welding Symposium...potential of the nugget. Susceptibility to stress corrosion cracking (SCC) was evaluated using the slow strain rate (SSR) method described in ASTM Standards...UNCLASSIFIED Defense Technical Information Center Compilation Part Notice ADP015941 TITLE: Corrosion Behavior of Friction Stir Welded High Strength

  8. Microstructural Evolution in Friction Stir Welding of Ti-5111

    DTIC Science & Technology

    2010-08-01

    industry for aluminum alloys. FSW of steels is under continued development. 1.1.3.1 Friction Stir Welding of Metals Since the development of...or friction welding [Titanium handbook]. A potential welding technique for titanium that has shown promise for joining aluminum and steel is...combatants, this research examines an alternative joining technology, friction stir welding ( FSW ). Friction stir welding uses a non-consumable tool to

  9. Cryogenic-storage-tank support

    NASA Technical Reports Server (NTRS)

    Wisdom, G. H.

    1980-01-01

    Support isolates tank from thermal and mechanical loading by environment. Design uses combination of well-known common mechanisms to isolate tank and allow for tank expansion and contraction due to temperature and pressure changes. Similar support method is used on nitrogen tanks.

  10. Two-tank suspended growth process for accelerating the detoxification kinetics of hydrocarbons requiring initial monooxygenation reactions.

    PubMed

    Dahlen, Elizabeth P; Rittmann, Bruce E

    2002-01-01

    An experimental evaluation demonstrated that suspended growth systems operated in a two-tank accelerator/aerator configuration significantly increased the overall removal rates for phenol and 2,4-dichlorophenol (2,4-DCP), aromatic hydrocarbons that require initial monooxygenations. The accelerator tank is a small volume that receives the influent and recycled biomass. It has a high ratio of electron donor (BOD) to electron acceptor (O2). Biomass in the accelerator should be enriched in reduced nicotinamide adenine dinucleotide (NADH + H+) and have a very high specific growth rate, conditions that should accelerate the kinetics of monooxygenation reactions. For the more slowly degraded 2,4-DCP, the average percentage removal increased from 74% to 93%, even though the volume of the two-tank system was smaller than that of the one-tank system in most experiments. The average volumetric and biomass-specific removal rates increased by 50% and 100%, respectively, in the two-tank system, compared to a one-tank system. The greatest enhancement in 2,4-DCP removal occurred when the accelerator tank comprised approximately 20% of the system volume. Biomass in the accelerator tank was significantly enriched in NADH + H+ when its dissolved oxygen (DO) concentration was below 0.25 mg/L, a situation having a high ratio of donor to acceptor. The accelerator biomass had its highest NADH + H+ content for the experiments that had the highest rate of 2,4-DCP removal. Biomass in the accelerator also had a much higher specific growth rate than in the aerator or the system overall, and the specific growth rate in the accelerator was inversely correlated to the accelerator volume.

  11. Multiple steady states in coupled flow tank reactors

    NASA Astrophysics Data System (ADS)

    Hunt, Katharine L. C.; Kottalam, J.; Hatlee, Michael D.; Ross, John

    1992-05-01

    Coupling between continuous-flow, stirred tank reactors (CSTR's), each having multiple steady states, can produce new steady states with different concentrations of the chemical species in each of the coupled tanks. In this work, we identify a kinetic potential ψ that governs the deterministic time evolution of coupled tank reactors, when the reaction mechanism permits a single-variable description of the states of the individual tanks; examples include the iodate-arsenous acid reaction, a cubic model suggested by Noyes, and two quintic models. Stable steady states correspond to minima of ψ, and unstable steady states to maxima or saddle points; marginally stable states typically correspond to saddle-node points. We illustrate the variation in ψ due to changes in the rate constant for external material intake (k0) and for exchange between tanks (kx). For fixed k0 values, we analyze the changes in numbers and types of steady states as kx increases from zero. We show that steady states disappear by pairwise coalescence; we also show that new steady states may appear with increasing kx, when the reaction mechanism is sufficiently complex. For fixed initial conditions, the steady state ultimately reached in a mixing experiment may depend on the exchange rate constant as a function of time, kx(t) : Adiabatic mixing is obtained in the limit of slow changes in kx(t) and instantaneous mixing in the limit as kx(t)→∞ while t remains small. Analyses based on the potential ψ predict the outcome of mixing experiments for arbitrary kx(t). We show by explicit counterexamples that a prior theory developed by Noyes does not correctly predict the instability points or the transitions between steady states of coupled tanks, to be expected in mixing experiments. We further show that the outcome of such experiments is not connected to the relative stability of steady states in individual tank reactors. We find that coupling may effectively stabilize the tanks. We provide

  12. Tool For Friction Stir Tack Welding of Aluminum Alloys

    NASA Technical Reports Server (NTRS)

    Bjorkman, Gerald W.; Dingler, Johnny W.; Loftus, Zachary

    2003-01-01

    A small friction-stir-welding tool has been developed for use in tack welding of aluminum-alloy workpieces. It is necessary to tack-weld the workpieces in order to hold them together during friction stir welding because (1) in operation, a full-size friction-stir-welding tool exerts a large force that tends to separate the workpieces and (2) clamping the workpieces is not sufficient to resist this force. It is possible to tack the pieces together by gas tungsten arc welding, but the process can be awkward and time-consuming and can cause sufficient damage to necessitate rework. Friction stir tack welding does not entail these disadvantages. In addition, friction stir tack welding can be accomplished by use of the same automated equipment (except for the welding tool) used in subsequent full friction stir welding. The tool for friction stir tack welding resembles the tool for full friction stir welding, but has a narrower shoulder and a shorter pin. The shorter pin generates a smaller workpiece-separating force so that clamping suffices to keep the workpieces together. This tool produces a continuous or intermittent partial-penetration tack weld. The tack weld is subsequently consumed by action of the larger tool used in full friction stir welding tool.

  13. 49 CFR 179.401 - Individual specification requirements applicable to inner tanks for cryogenic liquid tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... to inner tanks for cryogenic liquid tank car tanks. 179.401 Section 179.401 Transportation Other... TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid... requirements applicable to inner tanks for cryogenic liquid tank car tanks....

  14. Tank 48 - Chemical Destruction

    SciTech Connect

    Simner, Steven P.; Aponte, Celia I.; Brass, Earl A.

    2013-01-09

    Small tank copper-catalyzed peroxide oxidation (CCPO) is a potentially viable technology to facilitate the destruction of tetraphenylborate (TPB) organic solids contained within the Tank 48H waste at the Savannah River Site (SRS). A maturation strategy was created that identified a number of near-term development activities required to determine the viability of the CCPO process, and subsequent disposition of the CCPO effluent. Critical activities included laboratory-scale validation of the process and identification of forward transfer paths for the CCPO effluent. The technical documentation and the successful application of the CCPO process on simulated Tank 48 waste confirm that the CCPO process is a viable process for the disposition of the Tank 48 contents.

  15. TANK 5 SAMPLING

    SciTech Connect

    Vrettos, N; William Cheng, W; Thomas Nance, T

    2007-11-26

    Tank 5 at the Savannah River Site has been used to store high level waste and is currently undergoing waste removal processes in preparation for tank closure. Samples were taken from two locations to determine the contents in support of Documented Safety Analysis (DSA) development for chemical cleaning. These samples were obtained through the use of the Drop Core Sampler and the Snowbank Sampler developed by the Engineered Equipment & Systems (EES) group of the Savannah River National Laboratory (SRNL).

  16. The use of bottle caps as submerged aerated filter medium.

    PubMed

    Damasceno de Oliveira, Laurence; Motlagh, Amir Mohaghegh; Goel, Ramesh; de Souza Missagia, Beatriz; Alves de Abreu Filho, Benício; Lautenschlager, Sandro Rogério

    2014-01-01

    In this study, a submerged aerated filter (SAF) using bottle caps as a support medium was evaluated. The system was fed with effluent from an upflow anaerobic sludge blanket system at ETE 2-South wastewater treatment plant, under different volumetric organic load rates (VOLRs). The population of a particular nitrifying microbial community was assessed by fluorescent in situ hybridization with specific oligonucleotide probes. The system showed an average removal of chemical oxygen demand (COD) equal to 76% for VOLRs between 2.6 and 13.6 kg COD m(-3)_media.day(-1). The process of nitrification in conjunction with the removal of organic matter was observed from applying VOLRs lower than 5.5 kg COD m(-3)_media.day(-1) resulting in 78% conversion of NH4(+)-N. As the applied organic load was reduced, an increase in the nitrifying bacteria population was observed compared with total 4'-6-diamidino-2-phenylindole (DAPI) stained cells. Generally, SAF using bottle caps as a biological aerated filter medium treating wastewater from an anaerobic system showed promising removal of chemical oxygen demand (COD) and conversion of NH4(+)-N.

  17. Galvanic corrosion of nitinol under deaerated and aerated conditions.

    PubMed

    Pound, Bruce G

    2016-10-01

    Various studies have examined the corrosion rate of nitinol generally under deaerated conditions. Likewise, galvanic corrosion studies have typically involved deaerated solutions. This work addressed the effect of galvanic coupling on the corrosion current of electropolished nitinol in phosphate buffered saline and 0.9% sodium chloride under dearated and aerated conditions for times up to 24 h. Tests were performed on nitinol alone and coupled with MP35N in both the mechanically polished and passivated conditions. Aeration and galvanic coupling were found to have relatively little effect, indicating that the corrosion current is controlled by the anodic reaction. The current can be attributed entirely to Ni(2+) dissolution, which appears to be governed by solid-state mass transport of Ni(2+) through the passive oxide film. Because corrosion of EP nitinol is controlled by the anodic reaction, contact between EP nitinol and MP35N or other biomedical Co-Cr alloys is unlikely to result in significant galvanic effects in vivo. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1322-1327, 2016.

  18. Aerated Shewanella oneidensis in Continuously-fed Bioelectrochemical Systems for Power and Hydrogen Production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We studied the effects of aeration of Shewanella oneidensis on potentiostatic current production, iron(III) reduction, hydrogen production in a microbial electrolysis cell, and electric power generation in a microbial fuel cell. The potentiostatic performance of aerated S. oneidensis was considerab...

  19. Comparative analysis of oxygen transfer rate distribution in stirred bioreactor for simulated and real fermentation broths.

    PubMed

    Caşcaval, Dan; Galaction, Anca-Irina; Turnea, Marius

    2011-09-01

    Study of the distribution of the oxygen mass transfer coefficient, k (l) a, for a stirred bioreactor and simulated (pseudoplastic solutions of carboxymethylcellulose sodium salt) bacterial (P. shermanii), yeast (S. cerevisiae), and fungal (P. chrysogenum free mycelia) broths indicated significant variation of transfer rate with bioreactor height. The magnitude of the influence of the considered factors differed from one region to another. As a consequence of cell adsorption to bubble surface, the results indicated the impossibility of achieving a uniform oxygen transfer rate throughout the whole bulk of the microbial broth, even when respecting the conditions for uniform mixing. Owing to the different affinity of biomass for bubble surface, the positive influence of power input on k (l) a is more important for fungal broths, while increasing aeration is favorable only for simulated, bacterial and yeast broths. The influence of the considered factors on k (l) a were included in mathematical correlations established based on experimental data. For all considered positions, the proposed equations for real broths have the general expression [Formula in text] exhibiting good agreement with experimental results (with maximum deviations of ± 10.7% for simulated broths, ± 8.4% for P. shermanii, ± 9.3% for S. cerevisiae, and ± 6.6% for P. chrysogenum).

  20. Automated multisyringe stir bar sorptive extraction using robust montmorillonite/epoxy-coated stir bars.

    PubMed

    Ghani, Milad; Saraji, Mohammad; Maya, Fernando; Cerdà, Víctor

    2016-05-06

    Herein we present a simple, rapid and low cost strategy for the preparation of robust stir bar coatings based on the combination of montmorillonite with epoxy resin. The composite stir bar was implemented in a novel automated multisyringe stir bar sorptive extraction system (MS-SBSE), and applied to the extraction of four chlorophenols (4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol and pentachlorophenol) as model compounds, followed by high performance liquid chromatography-diode array detection. The different experimental parameters of the MS-SBSE, such as sample volume, selection of the desorption solvent, desorption volume, desorption time, sample solution pH, salt effect and extraction time were studied. Under the optimum conditions, the detection limits were between 0.02 and 0.34μgL(-1). Relative standard deviations (RSD) of the method for the analytes at 10μgL(-1) concentration level ranged from 3.5% to 4.1% (as intra-day RSD) and from 3.9% to 4.3% (as inter-day RSD at 50μgL(-1) concentration level). Batch-to-batch reproducibility for three different stir bars was 4.6-5.1%. The enrichment factors were between 30 and 49. In order to investigate the capability of the developed technique for real sample analysis, well water, wastewater and leachates from a solid waste treatment plant were satisfactorily analyzed.

  1. Nitrogen removal in intermittently aerated vertical flow constructed wetlands: impact of influent COD/N ratios.

    PubMed

    Fan, Jinlin; Wang, Wengang; Zhang, Bo; Guo, Yeye; Ngo, Huu Hao; Guo, Wenshan; Zhang, Jian; Wu, Haiming

    2013-09-01

    The performance response of eight vertical flow constructed wetlands (VFCWs) to different influent COD/N ratios and intermittent aeration in domestic wastewater treatment was investigated. Almost complete nitrification was obtained by intermittent aeration, which well developed alternate anaerobic and aerobic conditions for nitrification and denitrification. Sufficient carbon source supply resulted from influent COD/N ratio of 10 simultaneously obtained high removals of COD (96%), ammonia nitrogen (99%) and total nitrogen (90%) in intermittently aerated VFCWs. In all non-aerated VFCWs, poor nitrification was observed due to oxygen deficiency whilst high COD/N ratios further led to lower COD and nitrogen removal efficiency. The results suggest that intermittent aeration combined with high influent COD/N ratios could achieve high nitrogen removal in VFCWs.

  2. Friction Stir Weld Modeling at MSFC: Kinematics

    NASA Technical Reports Server (NTRS)

    Nunes, Arthur C., Jr.

    2000-01-01

    A "merry-go-round" computation model makes it easier to visualize how tracer experiments of varied sorts (chemical, shot, wire) are consistent with a "moving plug model" of flow around the friction stir welding pin-tool. The moving plug model comprises a twofold flow: 1. a primary rotation of a plug of metal with the tool, which moves metal around the tool by wiping it on and off the plug, and 2. a secondary, relatively slow circulation induced by the threads on the tool resembling a circular vortex ring around the tool.

  3. Forming of aluminium alloy friction stir welds

    NASA Astrophysics Data System (ADS)

    Bruni, Carlo

    2016-10-01

    The present paper aims at investigating, through analytical models, numerical models and experiments, the effect of the warm deformation phase, realised with an in temperature upsetting, on the weld previously performed by friction stir lap welding on aluminium alloy blanks. The investigation allows to show the deformation zones after upsetting that determine the homogenisation of the weld section. The analytical model allows to relate the friction factor with the upsetting load. The presence on the weld of not elevated friction factor values determines the deformation and localisation levels very useful for the weld. Such methodology allows to improve the weld itself with the forming phase.

  4. Gas fluidized-bed stirred media mill

    DOEpatents

    Sadler, III, Leon Y.

    1997-01-01

    A gas fluidized-bed stirred media mill is provided for comminuting solid ticles. The mill includes a housing enclosing a porous fluidizing gas diffuser plate, a baffled rotor and stator, a hollow drive shaft with lateral vents, and baffled gas exhaust exit ports. In operation, fluidizing gas is forced through the mill, fluidizing the raw material and milling media. The rotating rotor, stator and milling media comminute the raw material to be ground. Small entrained particles may be carried from the mill by the gas through the exit ports when the particles reach a very fine size.

  5. Friction Stir Welding Development at National Aeronautics and Space Administration-Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Bhat, Biliyar N.; Carter, Robert W.; Ding, Robert J.; Lawless, Kirby G.; Nunes, Arthur C., Jr.; Russell, Carolyn K.; Shah, Sandeep R.; Munafo, Paul M. (Technical Monitor)

    2001-01-01

    This paper presents an over-view of friction stir welding (FSW) process development and applications at Marshall Space Flight Center (MSFC). FSW process development started as a laboratory curiosity but soon found support from many users. The FSW process advanced very quickly and has found many applications both within and outside the aerospace industry. It is currently being adapted for joining key elements of the Space Shuttle External Tank for improved producibility and reliability. FSW process modeling is done to better understand and improve the process. Special tools have been developed to weld variable thickness materials including very thin and very thick materials. FSW is now being applied to higher temperature materials such as copper and to advanced materials such as metal matrix composites. FSW technology is being successfully transferred from MSFC laboratory to shop floors of many commercial companies.

  6. Friction Stir Welding Development at NASA-Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Bhat, Biliyar N.; Carter, Robert W.; Ding, Robert J.; Lawless, Kirby G.; Nunes, Arthur C., Jr.; Russell, Carolyn K.; Shah, Sandeep R.

    2001-01-01

    This paper presents an overview of friction stir welding (FSW) process development and applications at Marshall Space Flight Center (MSFC). FSW process development started as a laboratory curiosity but soon found support from many users. The FSW process advanced very quickly and has found many applications both within and outside the aerospace industry. It is currently being adapted for joining key elements of the Space Shuttle External Tank for improved producibility and reliability. FSW process modeling is done to better understand and improve the process. Special tools have been developed to weld variable thickness materials including thin and thick materials. FSW is now being applied to higher temperature materials such as copper and to advanced materials such as metal matrix composites. FSW technology is being successfully transferred from MSFC laboratory to shop floors of many commercial companies.

  7. Certification of a weld produced by friction stir welding

    DOEpatents

    Obaditch, Chris; Grant, Glenn J

    2013-10-01

    Methods, devices, and systems for providing certification of friction stir welds are disclosed. A sensor is used to collect information related to a friction stir weld. Data from the sensor is compared to threshold values provided by an extrinsic standard setting organizations using a certification engine. The certification engine subsequently produces a report on the certification status of the weld.

  8. A Rotating Plug Model of Friction Stir Welding Heat Transfer

    NASA Technical Reports Server (NTRS)

    Raghulapadu J. K.; Peddieson, J.; Buchanan, G. R.; Nunes, A. C.

    2006-01-01

    A simplified rotating plug model is employed to study the heat transfer phenomena associated with the fiction stir welding process. An approximate analytical solution is obtained based on this idealized model and used both to demonstrate the qualitative influence of process parameters on predictions and to estimate temperatures produced in typical fiction stir welding situations.

  9. Friction stir method for forming structures and materials

    DOEpatents

    Feng, Zhili; David, Stan A.; Frederick, David Alan

    2011-11-22

    Processes for forming an enhanced material or structure are disclosed. The structure typically includes a preform that has a first common surface and a recess below the first common surface. A filler is added to the recess and seams are friction stir welded, and materials may be stir mixed.

  10. Friction Stir Welding of Lightweight Vehicle Structures: Final Report

    SciTech Connect

    Sanella, M L

    2008-08-31

    The purpose of this Cooperative Research and Development Agreement (CRADA) between UTBattelle, LLC and Ford Motor Company was to establish friction stir welding (FSW) and friction stir processing as viable options for use in construction of lightweight substructures for trucks and cars, including engine cradles, suspension sub frames, instrument panel supports, and intake manifolds.

  11. Flow Patterns During Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Guerra, M.; Schmidt, C.; McClure, J. C.; Murr, L. E.; Nunes, A. C.; Munafo, Paul M. (Technical Monitor)

    2002-01-01

    Friction Stir Welding is a relatively new technique for welding that uses a cylindrical pin or nib inserted along the weld seam. The nib (usually threaded) and the shoulder in which it is mounted are rapidly rotated and advanced along the seam. Extreme deformation takes place leaving a fine equiaxed structure in the weld region., The flow of metal during Friction Stir Welding is investigated using a faying surface tracer and a nib frozen in place during welding. It is shown that material is transported by two processes. The first is a wiping of material from the advancing front side of the nib onto a zone of material that rotates and advances with the nib. The material undergoes a helical motion within the rotational zone that both rotates and advances and descends in the wash of the threads on the nib and rises on the outer part of the rotational zone. After one or more rotations, this material is sloughed off in its wake of the nib, primarily on the advancing side. The second process is an entrainment of material from the front retreating side of the nib that fills in between the sloughed off pieces from the advancing side.

  12. The Plunge Phase of Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Nunes, Arthur; McClure, John; Avila, Ricardo

    2005-01-01

    Torque and plunge force during the initial plunge phase in Friction Stir Welding were measured for a 0.5 inch diameter pin entering a 2219 aluminum alloy plate. Weld structures were preserved for metallographic observation by making emergency stops at various plunge depths. The plunging pin tool is seen to be surrounded by a very fine grained layer of recrystallized metal extending substantially below the bottom of the pin, implying a shear interface in the metal below and not at the tool-metal interface. Torque and plunge force during the initial plunge phase in Friction Stir Welding are calculated from a straight forward model based on a concept to plastic flow in the vicinity of the plunging tool compatible with structural observations. The concept: a disk of weld metal seized to and rotating with the bottom of the pin is squeezed out laterally by the plunge force and extruded upwards in a hollow cylinder around the tool. As the shear surface separating rotating disk from stationary weld metal engulfs fresh metal, the fresh metal is subjected to severe shear deformation, which results in its recrystallization. Encouraging agreement between computations and measured torque and plunge force is obtained.

  13. New Tool Creates a Big Stir

    NASA Technical Reports Server (NTRS)

    2001-01-01

    A new self-adjusting, retractable pin tool for friction stir welding is now used in the manufacturing of components for NASA Space Shuttles. Friction stir welding is a process that makes straight-line welds without bringing the parent material to a liquid state. This is accomplished through high-speed rotation, which generates frictional heat between the welding tool and the piece being welded. This heat causes the material to soften to the point of plasticity without allowing it to melt. The plasticized material is then transferred from the front edge of the welding tool to the trail edge, where it joins the pieces being welded. However, a major flaw of this method is its reliance on a single-piece pin tool. The weld is left unfinished and a hole remains where the pin was inserted. The hole must be covered with a rivet in order to preserve the integrity of the weld. The NASA-developed pin tool, however, eliminates the need for this finishing step, as its retraction allows continuous rewelding at lesser depths, until the hole is completely closed. With this NASA technology, welding of higher strength alloys, as well as non-planer and variable thickness structures can be achieved.

  14. Tank waste remediation system high-level waste feed processability assessment report

    SciTech Connect

    Lambert, S.L.; Kim, D.S.

    1994-12-01

    This study evaluates the effect of feed composition on the performance of the high-level vitrification process. It is assumed in this study that the tank wastes are retrieved and blended by tank farms, producing 12 different blends from the single-shell tank farms, two blends of double-shell tank waste, and a separately defined all-tank blend. This blending scenario was chosen only for evaluating the impact of composition on the volume of high- level waste glass produced. Special glass compositions were formulated for each waste blend based on glass property models and the properties of similar glasses. These glasses were formulated to meet the applicable viscosity, electrical conductivity, and liquidus temperature constraints for the identified candidate melters. Candidate melters in this study include the low-temperature stirred melter, which operates at 1050{degrees}C; the reference Hanford Waste Vitrification Plant liquid-fed ceramic melter, which operates at 1150{degrees}C; and the high-temperature, joule-heated melter and the cold-crucible melter, which operate over a temperature range of 1150{degrees}C to 1400{degrees}C. In the most conservative case, it is estimated that 61,000 MT of glass will be produced if the Site`s high-level wastes are retrieved by tank farms and processed in the reference joule-heated melter. If an all-tank blend was processed under the same conditions, the reference melter would produce 21,250 MT of glass. If cross-tank blending were used, it is anticipated that $2.0 billion could be saved in repository disposal costs (based on an average disposal cost of $217,000 per canister) by blending the S, SX, B, and T Tank Farm wastes with other wastes prior to vitrification. General blending among all the tank farms is expected to produce great potential benefit.

  15. Optical Cryogenic Tank Level Sensor

    NASA Technical Reports Server (NTRS)

    Duffell, Amanda

    2005-01-01

    Cryogenic fluids play an important role in space transportation. Liquid oxygen and hydrogen are vital fuel components for liquid rocket engines. It is also difficult to accurately measure the liquid level in the cryogenic tanks containing the liquids. The current methods use thermocouple rakes, floats, or sonic meters to measure tank level. Thermocouples have problems examining the boundary between the boiling liquid and the gas inside the tanks. They are also slow to respond to temperature changes. Sonic meters need to be mounted inside the tank, but still above the liquid level. This causes problems for full tanks, or tanks that are being rotated to lie on their side.

  16. Improving the Quality of Protein Crystals Using Stirring Crystallization

    NASA Astrophysics Data System (ADS)

    Adachi, Hiroaki; Matsumura, Hiroyoshi; Niino, Ai; Takano, Kazufumi; Kinoshita, Takayoshi; Warizaya, Masaichi; Inoue, Tsuyoshi; Mori, Yusuke; Sasaki, Takatomo

    2004-04-01

    Recent reports state that a high magnetic field improves the crystal quality of bovine adenosine deaminase (ADA) with an inhibitor [Kinoshita et al.: Acta Cryst. D59 (2003) 1333]. In this paper, we examine the effect of stirring solution on ADA crystallization using a vapor-diffusion technique with rotary and figure-eight motion shakers. The probability of obtaining high-quality crystals is increased with stirring in a figure-eight pattern. Furthermore, rotary stirring greatly increased the probability of obtaining high-quality crystals, however, nucleation time was also increased. The crystal structure with the inhibitor was determined at a high resolution using a crystal obtained from a stirred solution. These results indicate that stirring with simple equipment is as useful as the high magnetic field technique for protein crystallization.

  17. Grain misorientation in thixo-billets prepared by melt stirring

    SciTech Connect

    Nafisi, S.; Szpunar, J.; Vali, H.; Ghomashchi, R.

    2009-09-15

    For semi solid metal (SSM) slurries, in addition to the morphology, size, distribution and percentage of the solid phase particles, the microstructure of individual solid particles is another important parameter to be considered. This is particularly an issue when SSM billets are prepared by continuous stirring of the melt to temperatures below liquidus, as in the case of electromagnetic stirring of Al-Si alloys. Microstructural evolution of the electromagnetically stirred Al-Si alloy is investigated by means of optical and electron microscopy. Electron backscatter diffraction (EBSD) analysis of the stirred and unstirred cast billets has shown stirring to generate local misorientation within individual solid particles. This is an indication of growing dendrites undergoing plastic deformation during the course of SSM slurry preparation. The formation of dislocations and their subsequent rearrangement into subgrain boundaries has been shown by EBSD analysis and TEM studies of thin foil specimens respectively.

  18. High-Powered, Ultrasonically Assisted Thermal Stir Welding

    NASA Technical Reports Server (NTRS)

    Ding, Robert

    2013-01-01

    This method is a solid-state weld process capable of joining metallic alloys without melting. The weld workpieces to be joined by thermal stir welding (TSW) are drawn, by heavy forces, between containment plates past the TSW stir tool that then causes joining of the weld workpiece. TSW is similar to friction stir welding (FSW) in that material is heated into a plastic state (not melted) and stirred using a stir rod. The FSW pin tool is an integrated geometrical structure consisting of a large-diameter shoulder, and a smaller-diameter stir pin protruding from the shoulder. When the pin is plunged into a weld workpiece, the shoulder spins on the surface of the weld workpiece, thus inducing frictional heat into the part. The pin stirs the fraying surfaces of the weld joint, thus joining the weld workpiece into one structure. The shoulder and stir pin of the FSW pin tool must rotate together at a desired rotational speed. The induced frictional energy control and stir pin control of the pin tool cannot be de-coupled. The two work as one integrated unit. TSW, on the other hand, de-couples the heating and stirring of FSW, and allows for independent control of each process element. A uniquely designed induction coil heats the weld workpiece to a desired temperature, and once heated, the part moves into a stir rod whose RPM is also independently controlled. As the weld workpiece moves into the stir rod, the piece is positioned, or sandwiched, between upper and lower containment plates. The plate squeezes together, thus compressing the upper and lower surfaces of the weld workpiece. This compressive force, also called consolidation force, consolidates the plastic material within the weld nugget material as it is being stirred by the stir rod. The stir rod is positioned through the center of the top containment plate and protrudes midway through the opposite lower containment plate where it is mechanically captured. The upper and lower containment plates are separated by a

  19. Effect of stirring and seeding on whey protein fibril formation.

    PubMed

    Bolder, Suzanne G; Sagis, Leonard M C; Venema, Paul; van der Linden, Erik

    2007-07-11

    The effect of stirring and seeding on the formation of fibrils in whey protein isolate (WPI) solutions was studied. More fibrils of a similar length are formed when WPI is stirred during heating at pH 2 and 80 degrees C compared to samples that were heated at rest. Addition of seeds did not show an additional effect compared to samples that were stirred. We propose a model for fibril formation, including an activation, nucleation, growth, and termination step. The activation and nucleation steps are the rate-determining steps. Fibril growth is relatively fast but terminates after prolonged heating. Two processes that possibly induce termination of fibril growth are hydrolysis of nonassembled monomers and inactivation of the growth ends of the fibrils. Stirring may break up immature fibrils, thus producing more active fibrils. Stirring also seems to accelerate the kinetics of fibril formation, resulting in an increase of the number of fibrils formed.

  20. 131. NORTH PLANT TANK CHEMICAL STORAGE TANKS FROM GB MANUFACTURING ...

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

    131. NORTH PLANT TANK CHEMICAL STORAGE TANKS FROM GB MANUFACTURING PLANT. VIEW TO SOUTHEAST. - Rocky Mountain Arsenal, Bounded by Ninety-sixth Avenue & Fifty-sixth Avenue, Buckley Road, Quebec Street & Colorado Highway 2, Commerce City, Adams County, CO

  1. Material selection for Multi-Function Waste Tank Facility tanks

    SciTech Connect

    Larrick, A.P.; Blackburn, L.D.; Brehm, W.F.; Carlos, W.C.; Hauptmann, J.P.; Danielson, M.J.; Westerman, R.E.; Divine, J.R.; Foster, G.M.

    1995-03-01

    This paper briefly summarizes the history of the materials selection for the US Department of Energy`s high-level waste carbon steel storage tanks. It also provides an evaluation of the materials for the construction of new tanks at the evaluation of the materials for the construction of new tanks at the Multi-Function Waste Tank Facility. The evaluation included a materials matrix that summarized the critical design, fabrication, construction, and corrosion resistance requirements: assessed. each requirement: and cataloged the advantages and disadvantages of each material. This evaluation is based on the mission of the Multi-Function Waste Tank Facility. On the basis of the compositions of the wastes stored in Hanford waste tanks, it is recommended that tanks for the Multi-Function Waste Tank Facility be constructed of ASME SA 515, Grade 70, carbon steel.

  2. Methane biofiltration using autoclaved aerated concrete as the carrier material.

    PubMed

    Ganendra, Giovanni; Mercado-Garcia, Daniel; Hernandez-Sanabria, Emma; Boeckx, Pascal; Ho, Adrian; Boon, Nico

    2015-09-01

    The methane removal capacity of mixed methane-oxidizing bacteria (MOB) culture in a biofilter setup using autoclaved aerated concrete (AAC) as a highly porous carrier material was tested. Batch experiment was performed to optimize MOB immobilization on AAC specimens where optimum methane removal was obtained when calcium chloride was not added during bacterial inoculation step and 10-mm-thick AAC specimens were used. The immobilized MOB could remove methane at low concentration (~1000 ppmv) in a biofilter setup for 127 days at average removal efficiency (RE) of 28.7 %. Unlike a plug flow reactor, increasing the total volume of the filter by adding a biofilter in series did not result in higher total RE. MOB also exhibited a higher abundance at the bottom of the filter, in proximity with the methane gas inlet where a high methane concentration was found. Overall, an efficient methane biofilter performance could be obtained using AAC as the carrier material.

  3. Microstructural investigations of naturally and artificially weathered autoclaved aerated concrete

    SciTech Connect

    Kus, Huelya; Carlsson, Thomas

    2003-09-01

    The microstructural changes in autoclaved aerated concrete (AAC), particularly due to chemical degradation, have been investigated. The carbonation process has been studied on naturally and artificially weathered AAC by spectrographic and microscopic analysis. Visual inspections of unexposed and aged AAC were made by means of light optical microscopy and scanning electron microscopy (SEM), while chemical and structural analysis were based on X-ray diffraction (XRD) and energy-dispersive spectroscopy (EDS). The results obtained from two different experimental exposure set-ups, i.e., natural and artificial weathering, are presented. Thin-section images clearly indicate leaching out of the surface layer resulting in open larger air voids. Both naturally and artificially weathered samples displayed similar ageing characteristics in terms of mineralogical changes. The XRD patterns confirm that tobermorite were gradually transforming into calcium carbonate with exposure time. Calcite and gypsum were the two main crystal structures growing during weathering as detected in the SEM+EDS examinations.

  4. Cracking in autoclaved aerated concrete: Experimental investigation and XFEM modeling

    SciTech Connect

    Ferretti, D.

    2015-01-15

    The paper aims to investigate and model cracking development in beams and deep-beams made of autoclaved aerated concrete (AAC). Fracture mechanics of AAC has been first studied by performing three-point bending tests on beams, similar to those commonly used for ordinary concrete elements. In some of these tests, crack growth has been also monitored by using ESPI laser technique. In this way, it has been possible to calibrate the main parameters of a proper cohesive law by means of extended finite element inverse analysis. Subsequently, cracking tests have been also performed on deep-beams, whose behavior is more representative of full scale walls. To validate the proposed cohesive law, deep-beam experimental behavior has been finally simulated through XFEM.

  5. A mouse model of orthotopic vascularized aerated lung transplantation.

    PubMed

    Okazaki, M; Krupnick, A S; Kornfeld, C G; Lai, J M; Ritter, J H; Richardson, S B; Huang, H J; Das, N A; Patterson, G A; Gelman, A E; Kreisel, D

    2007-06-01

    Outcomes after lung transplantation are markedly inferior to those after other solid organ transplants. A better understanding of cellular and molecular mechanisms contributing to lung graft injury will be critical to improve outcomes. Advances in this field have been hampered by the lack of a mouse model of lung transplantation. Here, we report a mouse model of vascularized aerated single lung transplantation utilizing cuff techniques. We show that syngeneic grafts have normal histological appearance with minimal infiltration of T lymphocytes. Allogeneic grafts show acute cellular rejection with infiltration of T lymphocytes and recipient-type antigen presenting cells. Our data show that we have developed a physiological model of lung transplantation in the mouse, which provides ample opportunity for the study of nonimmune and immune mechanisms that contribute to lung allograft injury.

  6. [Effects of substrate-aeration cultivation pattern on tomato growth].

    PubMed

    Zhao, Xu; Li, Tian-Lai; Sun, Zhou-Ping

    2010-01-01

    Aeroponics can increase the fruit yield of tomato plant, but its cost is very high. In this paper, tomato seedlings were planted with three cultures, i. e., whole perlite culture (CK), perlite-aeration culture (T1), and aeroponics (T2), and a comparative study was made on the seedlings growth. Compared with CK, T1 improved the gas environment in root zone significantly, with the CO2 and O2 concentrations in root zone being 0.2 and 1.17 times higher, and increased the plant height and stem diameter after 60 days of transplanting by 5.1% and 8.4%, respectively. The plant net photosynthetic rate of T1 was significantly higher than that of CK, with the maximum value after transplanting 45 days increased by 13%. T1 also increased the root activity and ion absorbing ability significantly, with the root activity after transplanting 45 days being 1.23 times of CK, and the root K, Ca, and Mg contents after transplanting 60 days increased by 31%, 37%, and 27%, respectively. The fruit yield of T1 was 1.16 times of CK. No significant differences in these indices were observed between T1 and T2, and less difference in the fruit soluble sugar and organic acid contents as well as the sugar-acid ratio was found among CK, T1, and T2. It was suggested that perlite-aeration cultivation pattern was an easy and feasible way to markedly improve the fruit yield of tomato plant.

  7. Intensification of aeration in treating natural water and mine water

    SciTech Connect

    Bochkarev, G.R.; Beloborodov, A.V.; Kondrat`ev, S.A.

    1995-03-01

    Apart from problems in supplying potable water for coal mining regions, other problems exist - and are becoming more acute - in protection of the environment against pollution by domestic and mine waters, where the most urgent task is biological treatment and disinfection of wastewater to eliminate organic and bacterial contaminants. The principal method of disinfection is chlorination, which has well-known adverse effects on the human organism. Hence there is a great demand for the replacement of chlorinating agents by the less toxic and more effective ozonation method; however, the practical application of ozone treatment is limited by its relatively high cost and the unavailability of commercial-scale ozonators. An analysis of the current problems in water treatment in coal mining regions of the country shows that the typical schemes used today to treat natural and mine waters are very ineffective and unwieldy; also, in most cases they do not meet the required treating standards. Any progress in solving these problems can be expected only on the basis of fundamental advances in understanding the mechanism of the processes on which water-system treating technology is based. The results from research on intensification of aeration processes of water treatment, based on new concepts of the mechanism of mass transfer in water-air systems are presented. It is known that the aeration process, which serves basically to saturate the water with oxygen, is accomplished through contact between the water and air phases in which the decisive factor is the state of the surfaces and the interacting phases.

  8. Above- and underground storage tanks

    SciTech Connect

    Canning, K.; Kilbourne, A.

    1997-09-01

    Storage tanks are the primary means of storing liquid, fluid and gas products. Federal and state environmental regulations, as well as local building and fire codes, take into account leaks and spills, tank emissions, underground tank seepage and safety issues, and they define standards for tank manufacturers and owners. For specific regulatory information pertaining to your application, contact the local authorities having jurisdiction. Storage tanks listed within this product guide have been classified as underground or aboveground, with subcategories including modular, process and temporary tanks. Tank construction materials include aluminum, carbon steel, concrete, fiberglass-reinforced plastic (FRP) and stainless steel. A variety of accessories, including automatic tank gauging systems, level monitors, leak detectors, overfill protection and tank inspection systems, also are listed. Aboveground storage tanks (ASTs) have less than 10 percent of their tank volume and piping below ground. Available in both vertical and horizontal configurations, they can be either erected in the field or fabricated in a factory. Underground storage tanks (USTs) are primarily used to contain regulated substances; USTs have at least 10% of their tank volume and piping buried belowground. Common UST construction materials include carbon steel, coated steel, cathodically protected steel and FRP. USTs are required to have corrosion protection, spill and overfill prevention and control and release detection in place by December 1998.

  9. Composite overwrapped metallic tanks

    NASA Technical Reports Server (NTRS)

    Caudill, C. L.; Kirlin, R. L.

    1972-01-01

    Work is reported for fabricating and testing the fiberglass overwrapped titanium pressure vessel for cryogenic service. Difficulties encountered in the tank liner fabrication phase involved explosive forming, vacuum annealing, chemical milling and electron beam welding. While each of these processes and the nondestructive test methods employed are normally considered to be individually reliable, the combination of poor material together with fabrication and development reversals prevented the full achievement of the desired end results. Eight tanks plus a prototype and tool proofing article were produced. Six of the vessels failed during the hydrostatic sizing operation. One of the remaining tanks was hydrostatically pressurized to burst and the other was pressurized repeatedly at 75 F from 100 psi to the operating pressure until failure occurred. As a result, it is not possible to draw firm conclusions as to the true value of the design concept due to the problems encountered in the program.

  10. Fireman's Air Tanks

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Together with NASA's Johnson Space Center, A-T-O Inc.'s Scott Aviation has developed light-weight firefighter's air tanks. New backpack system weighs only 20 pounds for 30 minute air supply, 13 pounds less than conventional firefighting tanks. They are pressurized at 4,500 psi, (twice current tanks). Made of aluminum liner wrapped by resin-impregnated glass fibers, eliminating corrosion as well as lightening the load. Redesigned face mask permits better vision. Warning device to tell fireman he is running out of air is personalized so it can't be heard by others reducing confusion in an already hectic environment. Structural Composites Inc., The Boeing Co., and Martin- Marietta Corp. have developed uses for this technology.

  11. Enhancement of oxygen transfer efficiency in diffused aeration systems using liquid-film-forming apparatus.

    PubMed

    Zhu, H; Imai, T; Tani, K; Ukita, M; Sekine, M; Higuchi, T; Zhang, Z J

    2007-05-01

    Surface transfer and bubble transfer both contribute significantly to oxygen transfer in a diffused aeration system. In the present study, liquid-film-forming apparatus is successfully developed on a laboratory scale to improve considerably the surface transfer via the unique liquid film transfer technique. The experimental results show that the volumetric mass transfer coefficient for liquid-film-forming apparatus alone is found to be as much as 5.3 times higher than that for water surface and that the total volumetric mass transfer coefficient for liquid film aeration system increases by 37 % in comparison with conventional aeration system. Additionally, by tuning finely the structural parameters of the liquid-film-forming apparatus, it can also lead to high dissolved oxygen water with the dissolved oxygen percent saturation greater than 90 %. More importantly, this result is accomplished by simply offering a single-pass aeration at the depth as shallow as 26 cm. As a result, the objective of economical energy consumption in diffused aeration systems can be realized by lowering the aeration depth without sacrificing the aeration efficiency.

  12. Development of a model for activated sludge aeration systems: linking air supply, distribution, and demand.

    PubMed

    Schraa, Oliver; Rieger, Leiv; Alex, Jens

    2017-02-01

    During the design of a water resource recovery facility, it is becoming industry practice to use simulation software to assist with process design. Aeration is one of the key components of the activated sludge process, and is one of the most important aspects of modelling wastewater treatment systems. However, aeration systems are typically not modelled in detail in most wastewater treatment process modelling studies. A comprehensive dynamic aeration system model has been developed that captures both air supply and demand. The model includes sub-models for blowers, pipes, fittings, and valves. An extended diffuser model predicts both oxygen transfer efficiency within an aeration basin and pressure drop across the diffusers. The aeration system model allows engineers to analyse aeration systems as a whole to determine biological air requirements, blower performance, air distribution, control valve impacts, controller design and tuning, and energy costs. This enables engineers to trouble-shoot the entire aeration system including process, equipment and controls. It also allows much more realistic design of these highly complex systems.

  13. Influence of aeration intensity on mature aerobic granules in sequencing batch reactor.

    PubMed

    Gao, Da-Wen; Liu, Lin; Liang, Hong

    2013-05-01

    Aeration intensity is well known as an important factor in the formation of aerobic granules. In this research, two identical lab-scale sequencing batch reactors with aeration intensity of 0.8 (R1) and 0.2 m(3)/h (R2) were operated to investigate the characteristics and kinetics of matured aerobic granules. Results showed that both aeration intensity conditions induced granulation, but they showed different effects on the characteristics of aerobic granules. Compared with the low aeration intensity (R2), the aerobic granules under the higher aeration intensity (R1) had better physical characteristics and settling ability. However, the observed biomass yield (Y obs) in R1 [0.673 kg mixed liquor volatile suspended solids (MLVSS)/kg chemical oxygen demand (COD)] was lower than R2 (0.749 kg MLVSS/kg COD). In addition, the maximum specific COD removal rates (q max) and apparent half rate constant (K) of mature aerobic granular sludge under the two aeration intensities were at a similar level. Therefore, the matured aerobic granule system does not require to be operated in a higher aeration intensity, which will reduce the energy consumption.

  14. Magnetic resonance imaging studies of spontaneous capillary water imbibition in aerated gypsum

    NASA Astrophysics Data System (ADS)

    Song, Kyung-Min; Mitchell, Jonathan; Jaffel, Hamouda; Gladden, Lynn F.

    2011-03-01

    In this paper we investigate both capillary water imbibition and the sorptivity of aerated gypsum plaster, and how these sorption characteristics are related to the pore structure of the material. These characteristics are examined by monitoring mass change using the conventional gravimetric method and by obtaining water content profiles using non-destructive magnetic resonance imaging (MRI) techniques during capillary imbibition of water. Here, three different gypsum samples are investigated: one non-aerated reference gypsum sample and two aerated gypsum samples produced with different volumetric air fractions. The capillary water absorption into the reference sample follows t1/2 kinetics (Fickian diffusion), where t is the time of ingress. However, in the aerated gypsum samples there are deviations from t1/2 kinetics. The MRI results show unambiguously that two wetting fronts advance through the aerated structure; an observation that cannot be made from the gravimetric data alone. The water content profiles of the aerated gypsum samples are therefore analysed by treating them as the sum of two separate absorption processes using sharp front analysis. The capillary water absorption properties of this material are well described as a parallel combination of fast absorption into fine matrix pores and slow absorption into a modified structure of matrix pores inter-connected to air voids introduced into the slurry by aeration.

  15. Influence of aeration during propagation of pitching yeast on fermentation and beer flavor.

    PubMed

    Cheong, Chul; Wackerbauer, Karl; Kang, Soon Ah

    2007-02-01

    The effect of yeast propagated at different aeration conditions on yeast physiology, fermentation ability, and beer quality was investigated using three strains of Saccharomyces cerevisiae. It was shown that yeast cells grown under continuous aeration conditions during propagation were almost two times higher as compared with discontinuous aeration conditions. The maximum of cell growth of all samples reached between 36 h and 48 h. The concentration of trehalose was increased under continuous aerated yeasts, whereas glycogen was decreased. It was also observed that the concentration of glycogen and trehalose in yeast cells had no direct effect on subsequent fermentation ability. The effect of yeast propagated under different aeration conditions on subsequent fermentation ability was different from yeast strains, in which the influence will be most pronounced at the first fermentation. Later, the yeasts might regain its original characteristics in the following fermentations. Generally, continuously propagated yeast had a positive effect on beer quality in subsequent fermentation. Hence, the concentration of aroma compounds obtained with yeast propagated under 6 1/h for 48 h aeration was lower than those grown under other aeration conditions in the bottom yeasts; in particular, the amounts of phenylethyl alcohol, ester, and fatty acids were decreased.

  16. Demonstration of membrane aeration panels: City of Geneva Wastewater Treatment Plant. Final report

    SciTech Connect

    1995-01-01

    This report describes the design, construction, and testing of membrane aeration panels at the Marsh Creek wastewater treatment plant (WWTP) in Geneva, NY. The operators at the Geneva plant have undertaken a long-term program to upgrade wastewater treatment processes and lower operating costs. The aging mechanical surface aerators at the Marsh Creek treatment plant were replaced by a state-of-the-art membrane panel system. This fine-bubble diffused air system offers higher oxygen transfer efficiency than surface aerators or other types of fine-bubble diffused-air systems. The project had four objectives: to decrease the amount of electricity used at the plant for aeration; to enable the plant`s existing aeration basins to accommodate higher organic loads and/or nitrify the wastewater should the need arise; to provide an even distribution of dissolved oxygen within the aeration basins to enhance biological wastewater treatment activity; and to provide technical data to assess the performance of the membrane panel system versus other forms of wastewater aeration.

  17. Induction of mitochondrial aldehyde dehydrogenase by submergence facilitates oxidation of acetaldehyde during re-aeration in rice.

    PubMed

    Tsuji, Hiroyuki; Meguro, Naoki; Suzuki, Yasuhiro; Tsutsumi, Nobuhiro; Hirai, Atsushi; Nakazono, Mikio

    2003-07-10

    Post-hypoxic injuries in plants are primarily caused by bursts of reactive oxygen species and acetaldehyde. In agreement with previous studies, we found accumulations of acetaldehyde in rice during re-aeration following submergence. During re-aeration, acetaldehyde-oxidizing aldehyde dehydrogenase (ALDH) activity increased, thereby causing the acetaldehyde content to decrease in rice. Interestingly, re-aerated rice plants showed an intense mitochondrial ALDH2a protein induction, even though ALDH2a mRNA was submergence induced and declined upon re-aeration. This suggests that rice ALDH2a mRNA is accumulated in order to quickly metabolize acetaldehyde that is produced upon re-aeration.

  18. 33 CFR 157.15 - Slop tanks in tank vessels.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING... ballast water containing an oily mixture of 3 percent or more of the oil carrying capacity. Two percent... tank. (2) A new vessel of 70,000 tons DWT or more must have at least two slop tanks. (b) Capacity....

  19. 33 CFR 157.15 - Slop tanks in tank vessels.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING... ballast water containing an oily mixture of 3 percent or more of the oil carrying capacity. Two percent... tank. (2) A new vessel of 70,000 tons DWT or more must have at least two slop tanks. (b) Capacity....

  20. 33 CFR 157.15 - Slop tanks in tank vessels.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING... ballast water containing an oily mixture of 3 percent or more of the oil carrying capacity. Two percent... tank. (2) A new vessel of 70,000 tons DWT or more must have at least two slop tanks. (b) Capacity....

  1. 33 CFR 157.15 - Slop tanks in tank vessels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING... ballast water containing an oily mixture of 3 percent or more of the oil carrying capacity. Two percent... tank. (2) A new vessel of 70,000 tons DWT or more must have at least two slop tanks. (b) Capacity....

  2. 33 CFR 157.15 - Slop tanks in tank vessels.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING... ballast water containing an oily mixture of 3 percent or more of the oil carrying capacity. Two percent... tank. (2) A new vessel of 70,000 tons DWT or more must have at least two slop tanks. (b) Capacity....

  3. Tank plan for tank 241-C-104 retrieval testing

    SciTech Connect

    HERTING, D.L.

    1999-05-21

    Tank 241-C-104 has been identified as one of the first tanks to be retrieved for high-level waste pretreatment and immobilization. Retrieval of the tank waste will require dilution. Laboratory tests are needed to determine the amount of dilution required for safe retrieval and transfer of feed. The proposed laboratory tests are described in this document.

  4. Tank depletion flow controller

    DOEpatents

    Georgeson, Melvin A.

    1976-10-26

    A flow control system includes two bubbler tubes installed at different levels within a tank containing such as radioactive liquid. As the tank is depleted, a differential pressure transmitter monitors pressure differences imparted by the two bubbler tubes at a remote, shielded location during uniform time intervals. At the end of each uniform interval, balance pots containing a dense liquid are valved together to equalize the pressures. The resulting sawtooth-shaped signal generated by the differential pressure transmitter is compared with a second sawtooth signal representing the desired flow rate during each time interval. Variations in the two signals are employed by a control instrument to regulate flow rate.

  5. TANK SPACE OPTIONS REPORT

    SciTech Connect

    WILLIS WL; AHRENDT MR

    2009-08-11

    Since this report was originally issued in 2001, several options proposed for increasing double-shell tank (DST) storage space were implemented or are in the process of implementation. Changes to the single-shell tank (SST) waste retrieval schedule, completion of DST space saving options, and the DST space saving options in progress have delayed the projected shortfall of DST storage space from the 2007-2011 to the 2018-2025 timeframe (ORP-11242, River Protection Project System Plan). This report reevaluates options from Rev. 0 and includes evaluations of new options for alleviating projected restrictions on SST waste retrieval beginning in 2018 because of the lack of DST storage space.

  6. [Removal nitrogen of integrated vertical-flow constructed wetland under aeration condition].

    PubMed

    Tao, Min; He, Feng; Xu, Dong; Zhou, Qiao-Hong; Liang, Wei; Chen, Shui-Ping; Wu, Zhen-Bin

    2011-03-01

    Oxygen is an important limit factor of nitrogen removal in constructed wetlands, so it is the key point for improving nitrogen removal efficiency of constructed wetlands that the optimization of oxygen distribution within wetlands. Therefore, oxygen status, nitrogen removal and purification mechanism of integrated vertical-flow constructed wetland (IVCW) under aeration condition in summer and winter have been studied. The results showed that both oxygen levels and aerobic zones were increased in the wetland substrates. The area of oxic zone I (expressing with depth) extended from 22 cm, 17 cm to 53 cm, 44 cm, in summer and winter, respectively. The electric potential (Eh) profiling demonstrated that artificial aeration maintained the pattern of sequential oxic-anoxic-oxic (O-A-O) redox zones within the aerated IVCW in winter, while only two oxic-anoxic (O-A) zones were present inside the non-aerated IVCW in the cold season. The decomposition of organic matter and nitrification were obviously enhanced by artificial aeration since the removal efficiency of COD, TN and NH4(+) -N were increased by 12.2%, 6.9% and 15.1% in winter, respectively. There was no significant accumulation of NO3(-) -N in the effluent with an aeration cycle of 8 h on and 16 h off in this experiment. Moreover, we found that oxic zone I was the main region of pollutants removal in IVCW system, and artificial aeration mainly acted to enhance the purification capacity of this oxic zone in the aerated IVCW. These results suggest that aeration is important for optimization and application of IVCW system.

  7. Design of nonlinear PID controller and nonlinear model predictive controller for a continuous stirred tank reactor.

    PubMed

    Prakash, J; Srinivasan, K

    2009-07-01

    In this paper, the authors have represented the nonlinear system as a family of local linear state space models, local PID controllers have been designed on the basis of linear models, and the weighted sum of the output from the local PID controllers (Nonlinear PID controller) has been used to control the nonlinear process. Further, Nonlinear Model Predictive Controller using the family of local linear state space models (F-NMPC) has been developed. The effectiveness of the proposed control schemes has been demonstrated on a CSTR process, which exhibits dynamic nonlinearity.

  8. Numerical Bifurcation Analysis of Delayed Recycle Stream in a Continuously Stirred Tank Reactor

    NASA Astrophysics Data System (ADS)

    Gangadhar, Nalwala Rohitbabu; Balasubramanian, Periyasamy

    2010-10-01

    In this paper, we present the stability analysis of delay differential equations which arise as a result of transportation lag in the CSTR-mechanical separator recycle system. A first order irreversible elementary reaction is considered to model the system and is governed by the delay differential equations. The DDE-BIFTOOL software package is used to analyze the stability of the delay system. The present analysis reveals that the system exhibits delay independent stability for isothermal operation of the CSTR. In the absence of delay, the system is dynamically unstable for non-isothermal operation of the CSTR, and as a result of delay, the system exhibits delay dependent stability.

  9. Stabilization of unstable steady states of a continuous stirred tank bioreactor with predator-prey kinetics.

    PubMed

    Tabiś, Bolesław; Skoneczny, Szymon

    2013-07-20

    Nonlinear properties of a bioreactor with a developed microbiological predator-prey food chain are discussed. The presence of the predator microorganism completely changes the position and stability of the stationary states. A wide range of unstable steady states appears, associated with high amplitude oscillations of the state variables. Without automatic control such a system can only operate in transient states, with the yield undergoing periodic changes following the dynamics of the stable limit cycle. Technologically, this is undesirable. It has been shown that the oscillations can be removed by employing continuous P or PI controllers. Moreover, with a PI-controller, the predator can be eliminated from the system.

  10. A Mathematical model for ethanol production by extractive fermentation in a continuous stirred tank fermentor.

    PubMed

    Kollerup, F; Daugulis, A J

    1985-09-01

    Extractive fermentation is a technique that can be used to reduce the effect of end product inhibition through the use of a water-immiscible phase that removes fermentation products in situ. This has the beneficial effect of not only removing inhibitory products as they are formed (thus keeping reaction rates high) but also has the potential for reducing product recovery costs. We have chosen to examine the ethanol fermentation as a model system for end product inhibition and extractive fermentation and have developed a computer model predicting the productivity enhancement possible with this technique together with other key parameters such as extraction efficiency and residual glucose concentration. The model accommodates variable liquid flowrates entering and leaving the system, since it was found that the aqueous outlet flowrate could be up to 35% lower than the inlet flowrate during extractive fermentation of concentrated glucose feeds due to the continuous removal of ethanol from the fermentation broth by solvent extraction. The model predicts a total ethanol productivity of 82.6 g/L h if a glucose feed of 750 g/L is fermented with a solvent having a distribution coefficient of 0.5 at a solvent dilution rate of 5.0 h(-1). This is more than 10 times higher than for a conventional chemostat fermentation of a 250 g/L glucose feed. The model has furthermore illustrated the possible trade-offs that exist between obtaining a high extraction efficiency and a low residual glucose concentration.

  11. Biogas production from different substrates in an experimental Continuously Stirred Tank Reactor anaerobic digester.

    PubMed

    Fantozzi, Francesco; Buratti, Cinzia

    2009-12-01

    Different mixtures were digested in a single-stage, batch, mixed, laboratory scale mesophilic anaerobic digester at the Biomass Research Centre Laboratory (University of Perugia). The yield and the composition of biogas from the different substrates were evaluated and the cumulative curves were estimated. Two experimental campaigns were carried out, the first on three mixtures (chicken, pig and bovine manures), the second on animal and vegetal biomasses (chicken and cow manure, olive husk) with different inocula (rumen fluid and digested sludge). In the first campaign pig manure mixture showed the maximum biogas production (0.35 N m(3)/kg) and energy content (1.35 kWh/kg VS); in the second one the differences in produced biogas from the different inocula were analyzed: olive husk with piggery manure anaerobically digested as inoculum showed the higher biogas (0.28 N m(3)/kg VS) and methane yield (0.11 N m(3)/kg VS), corresponding to an energetic content of 1.07 kWh/kg VS. All data obtained from the laboratory scale anaerobic digester are comparable to the values in literature for several biomass and in particular for olive husk, dairy manure and chicken manure.

  12. Suppressing the Neurospora crassa circadian clock while maintaining light responsiveness in continuous stirred tank reactors

    PubMed Central

    Cockrell, Allison L.; Pirlo, Russell K.; Babson, David M.; Cusick, Kathleen D.; Soto, Carissa M.; Petersen, Emily R.; Davis, Miah J.; Hong, Christian I.; Lee, Kwangwon; Fitzgerald, Lisa A.; Biffinger, Justin C.

    2015-01-01

    Neurospora crassa has been utilized as a model organism for studying biological, regulatory, and circadian rhythms for over 50 years. These circadian cycles are driven at the molecular level by gene transcription events to prepare for environmental changes. N. crassa is typically found on woody biomass and is commonly studied on agar-containing medium which mimics its natural environment. We report a novel method for disrupting circadian gene transcription while maintaining light responsiveness in N. crassa when held in a steady metabolic state using bioreactors. The arrhythmic transcription of core circadian genes and downstream clock-controlled genes was observed in constant darkness (DD) as determined by reverse transcription-quantitative PCR (RT-qPCR). Nearly all core circadian clock genes were up-regulated upon exposure to light during 11hr light/dark cycle experiments under identical conditions. Our results demonstrate that the natural timing of the robust circadian clock in N. crassa can be disrupted in the dark when maintained in a consistent metabolic state. Thus, these data lead to a path for the production of industrial scale enzymes in the model system, N. crassa, by removing the endogenous negative feedback regulation by the circadian oscillator. PMID:26031221

  13. Enhanced Waste Tank Level Model

    SciTech Connect

    Duignan, M.R.

    1999-06-24

    'With the increased sensitivity of waste-level measurements in the H-Area Tanks and with periods of isolation, when no mass transfer occurred for certain tanks, waste-level changes have been recorded with are unexplained.'

  14. Tanks Emissions for TRI Reporting

    EPA Pesticide Factsheets

    A presentation on overcoming the challenges of TRI reporting for and monitoring the hazardous air emissions from storage tanks, including a discussion on the most accurate and feasible methods of correctly reporting tank emissions to the TRI Program.

  15. Numerical modelling of the strength of highly porous aerated autoclaved concrete

    SciTech Connect

    Schenider, T.; Greil, P.; Schober, G.

    1998-12-31

    Highly porous building materials like aerated autoclaved concrete are characterized by low thermal conductivity and high mechanical strength, which both strongly depend on porosity. The influence of porosity distribution on the compressive strength of aerated autoclaved concrete was investigated by using finite element analysis and multiaxial Weibull theory. Calculations of failure probability of microstructures with ordered as well as random pore configurations show a dependence of compressive strength on the Weibull modulus of the matrix material and the size and arrangement of pores. The results of the calculations are compared to experimental data of aerated autoclaved concrete.

  16. Enhanced long-term organics and nitrogen removal and associated microbial community in intermittently aerated subsurface flow constructed wetlands.

    PubMed

    Fan, Jinlin; Zhang, Jian; Guo, Wenshan; Liang, Shuang; Wu, Haiming

    2016-08-01

    The long-term enhanced removal efficiency of organics and nitrogen in subsurface flow constructed wetlands (SSF CWs) with and without intermittent aeration for decentralized domestic wastewater was evaluated, and the function of intermittent aeration on microbial community was also investigated in this study. The high and long-term 95.6% COD, 96.1% NH4(+)-N and 85.8% TN removal efficiencies were achieved in experimental intermittently aerated SSF CW compared with non-aerated SSF CW. Aerated SSF CWs also exhibited the excellent removal performance when comparatively comparing with other strategies and techniques applied in CWs. In addition, fluorescence in situ hybridization (FISH) analysis revealed that associated microbial abundance significantly increased owing to intermittent aeration. These results indicated intermittent aeration CWs might be an effective and sustainable strategy for wastewater treatment in rural areas, but require further full-scale investigation in future.

  17. Improving microalgal growth with reduced diameters of aeration bubbles and enhanced mass transfer of solution in an oscillating flow field.

    PubMed

    Yang, Zongbo; Cheng, Jun; Lin, Richen; Zhou, Junhu; Cen, Kefa

    2016-07-01

    A novel oscillating gas aerator combined with an oscillating baffle was proposed to generate smaller aeration bubbles and enhance solution mass transfer, which can improve microalgal growth in a raceway pond. A high-speed photography system (HSP) was used to measure bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure mass-transfer coefficient and mixing time. Bubble diameter and generation time decreased with decreased aeration gas rate, decreased orifice diameter, and increased water velocity in the oscillating gas aerator. The optimized oscillating gas aerator decreased bubble diameter and generation time by 25% and 58%, respectively, compared with a horizontal tubular gas aerator. Using an oscillating gas aerator and an oscillating baffle in a raceway pond increased the solution mass-transfer coefficient by 15% and decreased mixing time by 32%; consequently, microalgal biomass yield increased by 19%.

  18. Metal Flow in Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Nunes, Arthur C., Jr.

    2006-01-01

    The plastic deformation field in Friction Stir Welding (FSW) is compared to that in metal cutting. A shear surface around the FSW tool analogous to the metal cutting shear plane is identified and comprises the basis of the "rotating plug" flow field model and the "wiping" model of tool interaction with weld metal. Within the context of these models: The FSW shear rate is estimated to be comparable to metal cutting shear rates. The effect of tool geometry on the FSW shear surface is discussed and related to published torque measurements. Various FS W structural features are explained, including a difference in structure of bimetallic welds when alloys on the advancing and retreating sides of the weld seam are exchanged. The joining mechanism and critical parameters of the FSW process are made clear.

  19. Tool Forces Developed During Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Melendez, M.; Tang, W.; Schmidt, C.; McClure, J. C.; Nunes, A. C.; Murr, L. E.

    2003-01-01

    This paper will describe a technique for measuring the various forces and the torque that exist on the Friction Stir Welding pin tool. Results for various plunge depths, weld speeds, rotational speed, and tool configurations will be presented. Welds made on 6061 aluminum with typical welding conditions require a downward force of 2800 lbs. (12.5 kN) a longitudinal force in the direction of motion of 300 lbs (1.33 kN), a transverse force in the omega x v direction of 30 lbs (135 N). Aluminum 2195 under typical weld conditions requires a downward force of 3100 lbs. (1.38 kN), a longitudinal force of 920 lbs. (4.1 kN), and a transverse force of 45 lbs. (200 N) in the omega x v direction.

  20. Laser Peening Effects on Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Hatamleh, Omar

    2011-01-01

    Friction Stir Welding (FSW) is a welding technique that uses frictional heating combined with forging pressure to produce high strength bonds. It is attractive for aerospace applications. Although residual stresses in FSW are generally lower when compared to conventional fusion welds, recent work has shown that significant tensile residual stresses can be present in the weld after fabrication. Therefore, laser shock peening was investigated as a means of moderating the tensile residual stresses produced during welding. This slide presentation reviews the effect of Laser Peening on the weld, in tensile strength, strain, surface roughness, microhardness, surface wear/friction, and fatigue crack growth rates. The study concluded that the laser peening process can result in considerable improvement to crack initiaion, propagation and mechanical properties in FSW.

  1. Ultrasonically-assisted Thermal Stir Welding System

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey (Inventor)

    2014-01-01

    A welding head assembly has a work piece disposed between its containment plates' opposing surfaces with the work piece being maintained in a plastic state thereof at least in a vicinity of the welding head assembly's stir rod as the rod is rotated about its longitudinal axis. The welding head assembly and the work piece experience relative movement there between in a direction perpendicular to the rod's longitudinal axis as the work piece is subjected to a compressive force applied by the containment plates. A first source coupled to the first containment plate applies a first ultrasonic wave thereto such that the first ultrasonic wave propagates parallel to the direction of relative movement. A second source coupled to the second containment plate applies a second ultrasonic wave thereto such that the second ultrasonic wave propagates parallel to the direction of relative movement.propagates parallel to the direction of relative movement.

  2. VOLUMETRIC TANK TESTING: AN OVERVIEW

    EPA Science Inventory

    This report summarizes the technical findings of an EPA study on volumetric tank testing. It describes the results of the EPA study, which evaluated the viability of volumetric tank tests as a means of detecting leaks in underground storage tanks. It explains the accuracy requi...

  3. VOLUMETRIC TANK TESTING: AN OVERVIEW

    EPA Science Inventory

    This report summarizes the technical findings of an EPA study on volumetric tank testing. The results of this study, which evaluated the viability of volumetric tank tests as a means of detecting leaks in underground storage tanks, are described. Also, the accuracy requirements s...

  4. In-process discontinuity detection during friction stir welding

    NASA Astrophysics Data System (ADS)

    Shrivastava, Amber

    The objective of this work is to develop a method for detecting the creation of discontinuities (e.g., voids) during friction stir welding. Friction stir welding is inherently cost-effective, however, the need for significant weld inspection can make the process cost-prohibitive. A new approach to weld inspection is required -- where an in-situ characterization of weld quality can be obtained, reducing the need for post-process inspection. Friction stir welds with discontinuity and without discontinuity were created. In this work, discontinuities are generated by reducing the friction stir tool rotation frequency and increasing the tool traverse speed in order to create "colder" welds. During the welds, forces are measured. Discontinuity sizes for welds are measured by computerized tomography. The relationship between the force transients and the discontinuity sizes indicate that the force measurement during friction stir welding can be effectively used for detecting discontinuities in friction stir welds. The normalized force transient data and normalized discontinuity size are correlated to develop a criterion for discontinuity detection. Additional welds are performed to validate the discontinuity detection method. The discontinuity sizes estimated by the force measurement based method are in good agreement with the discontinuity sizes measured by computerized tomography. These results show that the force measurement based discontinuity detection model method can be effectively used to detect discontinuities during friction stir welding.

  5. The effect of impeller type on silica sol formation in laboratory scale agitated tank

    NASA Astrophysics Data System (ADS)

    Nurtono, Tantular; Suprana, Yayang Ade; Latif, Abdul; Dewa, Restu Mulya; Machmudah, Siti; Widiyastuti, Winardi, Sugeng

    2016-02-01

    The multiphase polymerization reaction of the silica sol formation produced from silicic acid and potassium hydroxide solutions in laboratory scale agitated tank was studied. The reactor is equipped with four segmental baffle and top entering impeller. The inside diameter of reactor is 9 cm, the baffle width is 0.9 cm, and the impeller position is 3 cm from tank bottom. The diameter of standard six blades Rushton and three blades marine propeller impellers are 5 cm. The silicic acid solution was made from 0.2 volume fraction of water glass (sodium silicate) solution in which the sodium ion was exchanged by hydrogen ion from cation resin. The reactor initially filled with 286 ml silicic acid solution was operated in semi batch mode and the temperature was kept constant in 60 °C. The 3 ml/minute of 1 M potassium hydroxide solution was added into stirred tank and the solution was stirred. The impeller rotational speed was varied from 100 until 700 rpm. This titration was stopped if the solution in stirred tank had reached the pH of 10-The morphology of the silica particles in the silica sol product was analyzed by Scanning Electron Microscope (SEM). The size of silica particles in silica sol was measured based on the SEM image. The silica particle obtained in this research was amorphous particle and the shape was roughly cylinder. The flow field generated by different impeller gave significant effect on particle size and shape. The smallest geometric mean of length and diameter of particle (4.92 µm and 2.42 µm, respectively) was generated in reactor with marine propeller at 600 rpm. The reactor with Rushton impeller produced particle which the geometric mean of length and diameter of particle was 4.85 µm and 2.36 µm, respectively, at 150 rpm.

  6. Plating Tank Control Software

    SciTech Connect

    Krafcik, John

    1998-03-01

    The Plating Tank Control Software is a graphical user interface that controls and records plating process conditions for plating in high aspect ratio channels that require use of low current and long times. The software is written for a Pentium II PC with an 8 channel data acquisition card, and the necessary shunt resistors for measuring currents in the millampere range.

  7. Hybrid Tank Technology

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Researchers have accomplished great advances in pressure vessel technology by applying high-performance composite materials as an over-wrap to metal-lined pressure vessels. These composite over-wrapped pressure vessels (COPVs) are used in many areas, from air tanks for firefighters and compressed natural gas tanks for automobiles, to pressurant tanks for aerospace launch vehicles and propellant tanks for satellites and deep-space exploration vehicles. NASA and commercial industry are continually striving to find new ways to make high-performance pressure vessels safer and more reliable. While COPVs are much lighter than all-metal pressure vessels, the composite material, typically graphite fibers with an epoxy matrix resin, is vulnerable to impact damage. Carbon fiber is most frequently used for the high-performance COPV applications because of its high strength-to-weight characteristics. Other fibers have been used, but with limitations. For example, fiberglass is inexpensive but much heavier than carbon. Aramid fibers are impact resistant but have less strength than carbon and their performance tends to deteriorate.

  8. Wastewater treatment by radial freezing with stirring effects.

    PubMed

    Gay, Guillaume; Lorain, Olivier; Azouni, Aza; Aurelle, Yves

    2003-05-01

    Radial freezing experiments on wastewater models were conducted in the presence of imposed stirring in order to remove impurities. The studied samples (dilute Na-montmorillonite suspensions charged with nitrates and with zinc or lead) were placed inside a cylindrical annulus, cooled at a controlled temperature around -7 degrees C at its inner wall which rotated around a vertical axis. The freezing front propagated toward the still outer wall which was maintained at a constant temperature around +1 degrees C. Thanks to stirring, considerable purification rates up to 99.97% were attained. It was also demonstrated that combining radial freezing and stirring ended in residual concentrations which agreed with drinking water standards.

  9. Friction stir processing on high carbon steel U12

    SciTech Connect

    Tarasov, S. Yu. Rubtsov, V. E.; Melnikov, A. G.

    2015-10-27

    Friction stir processing (FSP) of high carbon steel (U12) samples has been carried out using a milling machine and tools made of cemented tungsten carbide. The FSP tool has been made in the shape of 5×5×1.5 mm. The microstructural characterization of obtained stir zone and heat affected zone has been carried out. Microhardness at the level of 700 MPa has been obtained in the stir zone with microstructure consisting of large grains and cementitte network. This high-level of microhardness is explained by bainitic reaction developing from decarburization of austenitic grains during cementite network formation.

  10. Friction Stir Spot Welding of Advanced High Strength Steels

    SciTech Connect

    Hovanski, Yuri; Grant, Glenn J.; Santella, M. L.

    2009-11-13

    Friction stir spot welding techniques were developed to successfully join several advanced high strength steels. Two distinct tool materials were evaluated to determine the effect of tool materials on the process parameters and joint properties. Welds were characterized primarily via lap shear, microhardness, and optical microscopy. Friction stir spot welds were compared to the resistance spot welds in similar strength alloys by using the AWS standard for resistance spot welding high strength steels. As further comparison, a primitive cost comparison between the two joining processes was developed, which included an evaluation of the future cost prospects of friction stir spot welding in advanced high strength steels.

  11. Tank characterization report for Single-Shell Tank T-102

    SciTech Connect

    Remund, K.M.; Hartley, S.A.; Toth, J.J.; Tingey, J.M.; Heasler, P.G.; Ryan, F.M.; Simpson, B.C.

    1994-09-01

    Tank 241-T-102 (hereafter referred to as T-102) is a 530,000 gallon single-shell waste tank located in the 200 West T Tank farm at the Hanford Site. In 1993, two cores were taken from this tank and analysis of the cores was conducted by Battelle`s 325-A Laboratory. Characterization of the waste in this tank was conducted to support Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-44-05. Tank T-102 was constructed in 1943 and put into service in 1945; it is the second tank in a cascade system with Tanks T-101 and T-103. During its process history, Tank T-102 received mostly Metal Waste (MW) from the Bismuth Phosphate Process and Coating Waste (CW) from the REDOX Process via the cascade from Tank T-101 and in transfers from Tank C-102. In 1956, the MW was removed from T-102 by pumping and sluicing`. This tank was declared inactive and retired from service in 1976. In 1981, intrusion prevention and stabilization measures were taken to isolate the waste in T-102. The tank presently contains approximately 121,100 liters (32,000 gallons) of liquid and sludge-like waste. Historically, there are no unreviewed safety issues associated with this tank and none were revealed after reviewing the data from the latest core sampling event in 1993. An extensive set of analytical measurements was performed on the core composites. The major constituents (>0.5 wt%) of the waste are water, aluminum, sodium, iron, and nitrate, ordered from the largest concentration to the smallest. The concentrations and inventories of these and other constituents are given. The results of the chemical analyses have been compared to the dangerous waste codes in the Washington Dangerous Waste Regulations (WAC 173-303).

  12. 49 CFR 179.500 - Specification DOT-107A * * * * seamless steel tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Specification DOT-107A * * * * seamless steel tank...) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500 Specification DOT-107A * * * * seamless steel tank car tanks....

  13. 49 CFR 179.500 - Specification DOT-107A * * * * seamless steel tank car tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Specification DOT-107A * * * * seamless steel tank...) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500 Specification DOT-107A * * * * seamless steel tank car tanks....

  14. 49 CFR 179.500 - Specification DOT-107A * * * * seamless steel tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Specification DOT-107A * * * * seamless steel tank... REGULATIONS SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500 Specification DOT-107A * * * * seamless steel tank car tanks....

  15. 49 CFR 179.500 - Specification DOT-107A * * * * seamless steel tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Specification DOT-107A * * * * seamless steel tank...) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500 Specification DOT-107A * * * * seamless steel tank car tanks....

  16. 49 CFR 179.500 - Specification DOT-107A * * * * seamless steel tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Specification DOT-107A * * * * seamless steel tank...) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.500 Specification DOT-107A * * * * seamless steel tank car tanks....

  17. 49 CFR 179.301 - Individual specification requirements for multi-unit tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-unit tank car tanks. 179.301 Section 179.301 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.301 Individual specification requirements for multi-unit tank car tanks. (a) In addition...

  18. 49 CFR 179.201 - Individual specification requirements applicable to non-pressure tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... to non-pressure tank car tanks. 179.201 Section 179.201 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.201 Individual specification requirements applicable to non-pressure tank car tanks....

  19. 49 CFR 179.201 - Individual specification requirements applicable to non-pressure tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... to non-pressure tank car tanks. 179.201 Section 179.201 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.201 Individual specification requirements applicable to non-pressure tank car tanks....

  20. 49 CFR 179.301 - Individual specification requirements for multi-unit tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-unit tank car tanks. 179.301 Section 179.301 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.301 Individual specification requirements for multi-unit tank car tanks. (a) In addition...

  1. 49 CFR 179.400 - General specification applicable to cryogenic liquid tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... liquid tank car tanks. 179.400 Section 179.400 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400 General specification applicable to cryogenic liquid tank...

  2. 49 CFR 179.400 - General specification applicable to cryogenic liquid tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... liquid tank car tanks. 179.400 Section 179.400 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400 General specification applicable to cryogenic liquid tank...

  3. 49 CFR 179.101 - Individual specification requirements applicable to pressure tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... to pressure tank car tanks. 179.101 Section 179.101 Transportation Other Regulations Relating to... MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT... tank car tanks. Editorial Note: At 66 FR 45186, Aug. 28, 2001, an amendment published amending a...

  4. 49 CFR 179.301 - Individual specification requirements for multi-unit tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-unit tank car tanks. 179.301 Section 179.301 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.301 Individual specification requirements for multi-unit tank car tanks. (a) In addition...

  5. 49 CFR 179.201 - Individual specification requirements applicable to non-pressure tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... to non-pressure tank car tanks. 179.201 Section 179.201 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.201 Individual specification requirements applicable to non-pressure tank car tanks....

  6. 49 CFR 179.400 - General specification applicable to cryogenic liquid tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... liquid tank car tanks. 179.400 Section 179.400 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400 General specification applicable to cryogenic liquid tank...

  7. 49 CFR 179.301 - Individual specification requirements for multi-unit tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-unit tank car tanks. 179.301 Section 179.301 Transportation Other Regulations Relating to... MATERIALS REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.301 Individual specification requirements for multi-unit tank car tanks. (a)...

  8. FY2003 Visual examination of In Tank and Tank annuli at 241-SY tank farm

    SciTech Connect

    AFTANAS, B.L.

    2003-07-08

    This report documents the completion of the FY 2003 in-tank and annulus video inspections for the 241-SY tank farms. Representative photos of observed anomalies, water-streaks, corrosion deposits, pitting, and in-tank strains on the 241-SY-101, 102 & 103

  9. Micro-aeration for hydrogen sulfide removal from biogas

    NASA Astrophysics Data System (ADS)

    Duangmanee, Thanapong

    The presence of sulfur compounds (e.g. protein, sulfate, thiosulfate, sulfite, etc.) in the feed stream generates highly corrosive and odorous hydrogen sulfide during anaerobic digestion. The high sulfide level in the biogas stream is not only poisonous to many novel metal catalysts employed in thermo-catalytic processes but also reduces the quality of methane to produce renewable energy. This study used an innovative, low-maintenance, low-cost biological sulfide removal technology to remove sulfides simultaneously from both gas and liquid phase. ORP (Oxidation-Reduction-Potential) was used as the controlling parameter to precisely regulate air injection to the sulfide oxidizing unit (SOU). The microaeration technique provided just enough oxygen to partially oxidize sulfides to elemental sulfur without inhibiting methanogenesis. The SOU was equipped with a diffuser at the bottom for the dispersion of sulfide-laden biogas and injected air throughout the column. The SOU can be operated as a standalone unit or coupled with an anaerobic digester to simultaneously remove sulfide from the biogas and effluent. The integrated system was capable of reducing hydrogen sulfide in biogas from 2,450 to less than 2 ppmV with minimal sulfate production at the highest available sulfide loading rate of 0.24 kg/m3-day. More than 98% of sulfide removed was recovered as elemental sulfur. However, the standalone SOU was able to operate at high hydrogen sulfide loading of 1.46 kg/m 3-day at inlet sulfide concentration of 3000 ppmV and reduce the off-gas hydrogen sulfide concentrations to less than 10 ppmV. The experiment also revealed that the ORP controlled aeration was sensitive enough to prevent oxygen overdosing (dampening effect) during unexpected surges of aeration. Using generalized linear regression, a model predicting output H2S concentration based on input H2S concentrations, SOU medium heights, and biogas flow rates, was derived. With 95% confidence, output H2S concentration

  10. Examination of the operator and compensator tank role in urban wastewater treatment using activated sludge method.

    PubMed

    Mokhtari Azar, Akbar; Ghadirpour Jelogir, Ali; Nabi Bidhendi, Gholam Reza; Zaredar, Narges

    2011-04-01

    No doubt, operator is one of the main fundaments in wastewater treatment plants. By identifying the inadequacies, the operator could be considered as an important key in treatment plant. Several methods are used for wastewater treatment that requires spending a lot of cost. However, all investments of treatment facilities are usable when the expected efficiency of the treatment plant was obtained. Using experienced operator, this goal is more easily accessible. In this research, the wastewater of an urban community contaminated with moderated, diluted and highly concentrated pollution has been treated using surface and deep aeration treatment method. Sampling of these pilots was performed during winter 2008 to summer 2009. The results indicate that all analyzed parameters were eliminated using activated sludge and surface aeration methods. However, in activated sludge and deep aeration methods in combination with suitable function of operator, more pollutants could be eliminated. Hence, existence of operator in wastewater treatment plants is the basic principle to achieve considered efficiency. Wastewater treatment system is not intelligent itself and that is the operator who can organize even an inefficient system by its continuous presence. The converse of this fact is also real. Despite the various units and appropriate design of wastewater treatment plant, without an operator, the studied process cannot be expected highly efficient. In places frequently affected by the shock of organic and hydraulic loads, the compensator tank is important to offset the wastewater treatment process. Finally, in regard to microbial parameters, existence of disinfection unit is very useful.

  11. Survival of Salmonella enterica in aerated and nonaerated wastewaters from dairy lagoons.

    PubMed

    Ravva, Subbarao V; Sarreal, Chester Z

    2014-10-29

    Salmonella is the most commonly identified foodborne pathogen in produce, meat and poultry. Cattle are known reservoirs of Salmonella and the pathogen excreted in feces ends up in manure flush lagoons. Salmonella enterica survival was monitored in wastewater from on-site holding lagoons equipped or not with circulating aerators at two dairies. All strains had poor survival rates and none proliferated in waters from aerated or settling lagoons. Populations of all three Salmonella serovars declined rapidly with decimal reduction times (D) of <2 days in aerated microcosms prepared from lagoon equipped with circulators. Populations of Salmonella decreased significantly in aerated microcosms (D = 4.2 d) compared to nonaerated waters (D = 7.4 d) and in summer (D = 3.4 d) compared to winter (D = 9.0 d). We propose holding the wastewater for sufficient decimal reduction cycles in lagoons to yield pathogen-free nutrient-rich water for crop irrigations and fertilization.

  12. Improving microalgal growth with small bubbles in a raceway pond with swing gas aerators.

    PubMed

    Yang, Zongbo; Cheng, Jun; Liu, Jianzhong; Zhou, Junhu; Cen, Kefa

    2016-09-01

    A novel swing gas aerator was developed to generate small bubbles for improving the mass transfer coefficient and microalgal growth rate in a raceway pond. A high-speed photography system (HSP) was used to measure the bubble diameter and generation time, and online precise dissolved oxygen probes and pH probes were used to measure the mass transfer coefficient and mixing time. Bubble generation time and diameter decreased by 21% and 9%, respectively, when rubber gas aerators were swung in the microalgae solution. When water pump power and gas aeration rate increased in a raceway pond with swing gas aerators and oscillating baffles (SGAOB), bubble generation time and diameter decreased but solution velocity and mass transfer coefficient increased. The mass transfer coefficient increased by 25% and the solution velocity increased by 11% when SGAOB was used, and the microalgal biomass yield increased by 18%.

  13. Storage tanks under earthquake loading

    SciTech Connect

    Rammerstorfer, F.G.; Scharf, K. ); Fisher, F.D. )

    1990-11-01

    This is a state-of-the-art review of various treatments of earthquake loaded liquid filled shells by the methods of earthquake engineering, fluid dynamics, structural and soil dynamics, as well as the theory of stability and computational mechanics. Different types of tanks and different possibilities of tank failure will be discussed. The authors will emphasize cylindrical above-ground liquid storage tanks with vertical axis. But many of the treatments are also valid for other tank configurations. For the calculation of the dynamically activated pressure due to an earthquake a fluid-structure-soil interaction problem must be solved. The review will describe the methods, proposed by different authors, to solve this interaction problem. To study the dynamic behavior of liquid storage tanks, one must distinguish between anchored and unanchored tanks. In the case of an anchored tank, the tank bottom edge is fixed to the foundation. If the tank is unanchored, partial lifting of the tank's bottom may occur, and a strongly nonlinear problem has to be solved. They will compare the various analytical and numerical models applicable to this problem, in combination with experimental data. An essential aim of this review is to give a summary of methods applicable as tools for an earthquake resistant design, which can be used by an engineer engaged in the construction of liquid storage tanks.

  14. Effects of Annealing Process on the Formability of Friction Stir Welded Al-Li Alloy 2195 Plates

    NASA Technical Reports Server (NTRS)

    Chen, Po-Shou; Bradford, Vann; Russell, Carolyn

    2011-01-01

    Large rocket cryogenic tank domes have typically been fabricated using Al-Cu based alloys like Al-Cu alloy 2219. The use of aluminum-lithium based alloys for rocket fuel tank domes can reduce weight because aluminum-lithium alloys have lower density and higher strength than Al-Cu alloy 2219. However, Al-Li alloys have rarely been used to fabricate rocket fuel tank domes because of the inherent low formability characteristic that make them susceptible to cracking during the forming operations. The ability to form metal by stretch forming or spin forming without excessive thinning or necking depends on the strain hardening exponent "n". The stain hardening exponent is a measure of how rapidly a metal becomes stronger and harder. A high strain hardening exponent is beneficial to a material's ability to uniformly distribute the imposed strain. Marshall Space Flight Center has developed a novel annealing process that can achieve a work hardening exponent on the order of 0.27 to 0.29, which is approximately 50% higher than what is typically obtained for Al-Li alloys using the conventional method. The strain hardening exponent of the Al-Li alloy plates or blanks heat treated using the conventional method is typically on the order of 0.17 to 0.19. The effects of this novel annealing process on the formability of friction stir welded Al-Li alloy blanks are being studied at Marshall Space Flight Center. The formability ratings will be generated using the strain hardening exponent, strain rate sensitivity and forming range. The effects of forming temperature on the formability will also be studied. The objective of this work is to study the deformation behavior of the friction stir welded Al-Li alloy 2195 blank and determine the formability enhancement by the new annealing process.

  15. Operational stability of naringinase PVA lens-shaped microparticles in batch stirred reactors and mini packed bed reactors-one step closer to industry.

    PubMed

    Nunes, Mário A P; Rosa, M Emilia; Fernandes, Pedro C B; Ribeiro, Maria H L

    2014-07-01

    The immobilization of naringinase in PVA lens-shaped particles, a cheap and biocompatible hydrogel was shown to provide an effective biocatalyst for naringin hydrolysis, an appealing reaction in the food and pharmaceutical industries. The present work addresses the operational stability and scale-up of the bioconversion system, in various types of reactors, namely shaken microtiter plates (volume ⩽ 2 mL), batch stirred tank reactors (volume <400 mL) and a packed-bed reactor (PBR, 6.8 mL). Consecutive batch runs were performed with the shaken/stirred vessels, with reproducible and encouraging results, related to operational stability. The PBR was used to establish the feasibility for continuous operation, running continuously for 54 days at 45°C. The biocatalyst activity remained constant for 40 days of continuous operation. The averaged specific productivity was 9.07 mmol h(-1) g enzyme(-1) and the half-life of 48 days.

  16. Investigation of Microstructure and Microhardness in Self-Reacting Friction Stir Welded AA2014-T6 and AA2219-T87

    NASA Technical Reports Server (NTRS)

    Horton, K. Renee; McGill, Preston; Barkey, Mark

    2011-01-01

    Friction stir welding (FSW) is a solid state welding process with potential advantages for aerospace and automotive industries dealing with light alloys. Self-reacting friction stir welding (SR-FSW) is one variation of the FSW process being developed at the National Aeronautics and Space Administration (NASA) for use in the fabrication of propellant tanks. This work reports on the microstructure and microhardness of SR-FSW between two dissimilar aluminum alloys. Specifically, the study examines the cross section of the weld joint formed between an AA2014-T6 plate on the advancing side and an AA2219-T87 plate on the retreating side. The microstructural analysis shows an irregularly displaced weld seam from the advancing side past the thermo-mechanical affected zone (TMAZ) into the weld nugget region. There are sharp variations in the microhardness across the weld. These variations are described in the paper and mechanisms for their formation are discussed.

  17. Aeration effect on Spirulina platensis growth and γ-Linolenic acid production.

    PubMed

    Ronda, Srinivasa Reddy; Bokka, Chandra Sekhar; Ketineni, Chandrika; Rijal, Binod; Allu, Prasada Rao

    2012-01-01

    The influence of aeration on algal growth and gamma-linolenic acid (GLA) production in a bubble column photobioreactor was investigated. Studies were performed in a 20-L reactor at different aeration rates (0.2- 2.5 vvm). Static, continuous, and periodic operation of air resulted in 41.9%, 88.4%, and 108% air saturation of dissolved oxygen, for which the corresponding values of GLA were 2.3, 6.5, and 7.5 mg·g(-1) dry cell weight, respectively. An increase in the aeration rate from 0.2 to 2.5 vvm enhanced both the specific growth rate and GLA content under periodic sparging in the bicarbonate medium. With a 6-fold increase in the aeration rate, the GLA content of the alga increased by 69.64% (5.6-9.5 mg· g(-1) dry cell weight). In addition, the total fatty acid (TFA) content in dry biomass increased from 2.22% to 4.41%, whereas the algae maintained a constant GLA to TFA ratio within the aeration rate tested. The dependence of GLA production on the aeration rate was explained by interrelating the GLA production rate with the specific growth rate using the Luedeking and Piret mixed growth model.

  18. Bioreactor tests preliminary to landfill in situ aeration: a case study.

    PubMed

    Raga, Roberto; Cossu, Raffaello

    2013-04-01

    Lab scale tests in bioreactor were carried out in the framework of the characterization studies of a landfill where in situ aeration (possibly followed by landfill mining) had been proposed as part of the novel waste management strategy in a region in northern Italy. The tests were run to monitor the effects produced by aerobic conditions at different temperatures on waste sampled at different depths in the landfill, with focus on the carbon and nitrogen conversion during aeration. Temperatures ranging from 35 to 45°C were chosen, in order to evaluate possible inhibition of biodegradation processes (namely nitrification) at 45°C in the landfill. The results obtained showed positive effects of the aeration on leachate quality and a significant reduction of waste biodegradability. Although a delay of biodegradation processes was observed in the reactor run at 45°C, biodegradation rates increased after 2 months of aeration, providing very low values of the relevant parameters (as in the other aerated reactors) by the end of the study. Mass balances were carried out for TOC and NNH4(+); the findings obtained were encouraging and provided evidence of the effectiveness of carbon and nitrogen conversion processes in the aerated landfill simulation reactors.

  19. Ecophysiology of wetland plant roots: A modelling comparison of aeration in relation to species distribution

    USGS Publications Warehouse

    Sorrell, B.K.; Mendelssohn, I.A.; McKee, K.L.; Woods, R.A.

    2000-01-01

    This study examined the potential for inter-specific differences in root aeration to determine wetland plant distribution in nature. We compared aeration in species that differ in the type of sediment and depth of water they colonize. Differences in root anatomy, structure and physiology were applied to aeration models that predicted the maximum possible aerobic lengths and development of anoxic zones in primary adventitious roots. Differences in anatomy and metabolism that provided higher axial fluxes of oxygen allowed deeper root growth in species that favour more reducing sediments and deeper water. Modelling identified factors that affected growth in anoxic soils through their effects on aeration. These included lateral root formation, which occurred at the expense of extension of the primary root because of the additional respiratory demand they imposed, reducing oxygen fluxes to the tip and stele, and the development of stelar anoxia. However, changes in sediment oxygen demand had little detectable effect on aeration in the primary roots due to their low wall permeability and high surface impedance, but appeared to reduce internal oxygen availability by accelerating loss from laterals. The development of pressurized convective gas flow in shoots and rhizomes was also found to be important in assisting root aeration, as it maintained higher basal oxygen concentrations at the rhizome-root junctions in species growing into deep water. (C) 2000 Annals of Botany Company.

  20. Improving arachidonic acid fermentation by Mortierella alpina through multistage temperature and aeration rate control in bioreactor.

    PubMed

    Gao, Min-Jie; Wang, Cheng; Zheng, Zhi-Yong; Zhu, Li; Zhan, Xiao-Bei; Lin, Chi-Chung

    2016-05-18

    Effective production of arachidonic acid (ARA) using Mortierella alpina was conducted in a 30-L airlift bioreactor. Varying the aeration rate and temperature significantly influenced cell morphology, cell growth, and ARA production, while the optimal aeration rate and temperature for cell growth and product formation were quite different. As a result, a two-stage aeration rate control strategy was constructed based on monitoring of cell morphology and ARA production under various aeration rate control levels (0.6-1.8 vvm). Using this strategy, ARA yield reached 4.7 g/L, an increase of 38.2% compared with the control (constant aeration rate control at 1.0 vvm). Dynamic temperature-control strategy was implemented based on the fermentation performance at various temperatures (13-28°C), with ARA level in total cellular lipid increased by 37.1% comparing to a constant-temperature control (25°C). On that basis, the combinatorial fermentation strategy of two-stage aeration rate control and dynamic temperature control was applied and ARA production achieved the highest level of 5.8 g/L.