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Sample records for 5-l stirred tank

  1. Culture of human mesenchymal stem cells on microcarriers in a 5 l stirred-tank bioreactor.

    PubMed

    Rafiq, Qasim A; Brosnan, Kathryn M; Coopman, Karen; Nienow, Alvin W; Hewitt, Christopher J

    2013-08-01

    For the first time, fully functional human mesenchymal stem cells (hMSCs) have been cultured at the litre-scale on microcarriers in a stirred-tank 5 l bioreactor, (2.5 l working volume) and were harvested via a potentially scalable detachment protocol that allowed for the successful detachment of hMSCs from the cell-microcarrier suspension. Over 12 days, the dissolved O2 concentration was >45 % of saturation and the pH between 7.2 and 6.7 giving a maximum cell density in the 5 l bioreactor of 1.7 × 10(5) cells/ml; this represents >sixfold expansion of the hMSCs, equivalent to that achievable from 65 fully-confluent T-175 flasks. During this time, the average specific O2 uptake of the cells in the 5 l bioreactor was 8.1 fmol/cell h and, in all cases, the 5 l bioreactors outperformed the equivalent 100 ml spinner-flasks run in parallel with respect to cell yields and growth rates. In addition, yield coefficients, specific growth rates and doubling times were calculated for all systems. Neither the upstream nor downstream bioprocessing unit operations had a discernible effect on cell quality with the harvested cells retaining their immunophenotypic markers, key morphological features and differentiation capacity.

  2. Stirring system for radioactive waste water storage tank

    SciTech Connect

    Ogata, Yoshimune; Nishizawa, Kunihide . Radioisotope Research Center)

    1999-07-01

    A stirring system for 100-m[sup 3] radioactive liquid waste tanks was constructed to unify radioactive concentrations in the tank. The stirring system is effective in certifying that the radioactive concentrations in the tanks are less than the legal limits before they are drained away as waste liquid. This system is composed of discharge units, pipe lines, and a controller. The performance of the system was assessed by comparing the calculated red ink and [sup 32]P concentrations with those monitored at six locations in the tanks. The concentration reached equilibrium after stirring 60 o 120 min with discharge units equipped with six fixed openings configured in differing directions. Residual chlorine in city water used for dilution occasionally bleached the red ink and reduced its concentration. The adsorption of [sup 32]P by slime on the walls of the tanks storing actual waste water lowered the equilibrium concentration.

  3. Nonequilibrium chemical instabilities in continuous flow stirred tank reactors: The effect of stirring

    NASA Astrophysics Data System (ADS)

    Horsthemke, W.; Hannon, L.

    1984-11-01

    We present a stochastic model for stirred chemical reactors. In the limiting case of practical interest, i.e., fast stirring, we solve for the characteristic function in steady state and derive expressions for the stationary moments through a perturbation expansion. Moments are explicitly calculated for a generic model of bistable behavior. We find that stirring decreases the area of the bistable region essentially by changing the point of transition from the high reaction rate state to the low reaction rate state. This is in remarkable agreement with the experimental findings of Roux, et al. Our results indicate that stirring should not be considered simply as an ``enhanced diffusion'' process and that nucleation plays only a minor role in transitions between multiple steady states in a continuous flow stirred tank reactor (CSTR).

  4. 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.

  5. Shear-induced flocculation of colloidal particles in stirred tanks

    SciTech Connect

    Chin, C.J.; Yiacoumi, S.; Tsouris, C.

    1998-10-15

    Colloidal polystyrene and paramagnetic particles consisting of mixtures of polystyrene and magnetite are used to experimentally investigate flocculation kinetics in a stirred tank under turbulent shear flow. The effects of various parameters--agitation speed, solution pH, ionic strength, particle size, and particle concentration--on the flocculation rate are investigated. A trajectory model applicable for shear-flow systems is formulated to describe particle flocculation in stirred tanks. The collision efficiency of particles is obtained from the limiting trajectory of one particle moving toward another and is a function of interparticle forces and flow properties. The collision frequency is determined as a function of particle size and energy dissipation. The flocculation frequency is then determined by multiplying the collision frequency by the collision efficiency and is incorporated into a population balance model to predict the particle size evolution. Results suggest that the flocculation rate is enhanced by increasing the agitation speed, even though the collision efficiency is decreased at a higher agitation speed. It is also found that the collision rate increases and the collision efficiency decreases as the particle size ratio is increased. Results also suggest that the breakup rate of aggregates in a turbulent shear flow could be significant and may need to be included in the population balance modeling to correctly predict the evolution of particle size distribution.

  6. Kinetics of propionate conversion in anaerobic continuously stirred tank reactors.

    PubMed

    Nielsen, H B; Mladenovska, Z; Ahring, B K

    2008-02-01

    The kinetic parameters of anaerobic propionate degradation by biomass from 7 continuously stirred tank reactors differing in temperature, hydraulic retention time and substrate composition were investigated. In substrate-depletion experiments (batch) the maximum propionate degradation rate, Amax, and the half saturation constant, Km, were initially estimated by applying the integrated Michaelis-Menten equation. Amax was in the range from 22.8 to 29.1 micromol gVS(-1) h(-1) while Km was in the range from 0.46-0.95 mM. In general, Amax gave a good reflection of the reactor performances. Secondly, the accuracy of the applied method was evaluated by use of radiotracer methodology. Amax was found to be 14-15% lower in the substrate-depletion experiment than in the radioisotope experiment due to endogenous propionate production. By including the endogenous propionate production, a 42-49% lower Km was estimated. The results demonstrate that the rate of endogenous substrate (propionate) production should be taken into account when estimating kinetic parameters in biomass from manure-based anaerobic reactors.

  7. 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

  8. 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.

  9. New miniature stirred-tank bioreactors for parallel study of enzymatic biomass hydrolysis.

    PubMed

    Riedlberger, Peter; Weuster-Botz, Dirk

    2012-02-01

    Many factors strongly influence the enzymatic hydrolysis of biomass to fermentable sugars (feedstock composition, pretreatment, enzymes and enzyme loading). In order to optimize the reaction conditions for the hydrolysis of biomass, an accurate high-throughput bioprocess development tool is mandatory, which enables a parallelization and an easy scale-up. New S-shaped impellers were developed for magnetically inductive driven stirred-tank bioreactors at a 10mL-scale. An efficient and reproducible homogenization was shown at 20% w/w solids loading of microcrystalline cellulose and at, 4-10% with wheat straw in 48 parallel operated stirred-tank bioreactors. The scale-up was successfully validated for the enzymatic hydrolysis of wheat straw suspensions and microcrystalline cellulose mixtures by application of a cellulase complex at a milliliter- and liter-scale. As an example, the parallel stirred-tank bioreactor system was applied for the evaluation of enzymatic batch hydrolyses of plant materials with varying pretreatments.

  10. 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. PMID:16646479

  11. 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.

  12. 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.

  13. 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.

  14. 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…

  15. 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.

  16. Chaotic behavior in the dynamical system of a continuous stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Retzloff, D. G.; Chan, P. C.-H.; Chicone, C.; Offin, D.; Mohamed, R.

    1987-03-01

    The dynamical system describing a continuous stirred tank reactor (CSTR) for the reactions A→B→C and A→C, B→D is considered. A circulating attractor with accompanying circulating orbits is shown to exist when the critical point of the system is unique and unstable. The orbit structure has been numerically found to consist of periodic orbits and chaotic behavior.

  17. 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.

  18. 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.

  19. 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

  20. Modelling of solids distribution in stirred tanks: analysis of simulation strategies and comparison with experimental data

    NASA Astrophysics Data System (ADS)

    Montante, G.; Magelli, F.

    2005-03-01

    The predictive capabilities of CFD techniques as applied to solid liquid stirred vessels are investigated. The distribution of solid particles was simulated in three baffled stirred tanks agitated with single and multiple impellers. Suspensions of glass beads of different diameters and average concentration up to 6 vol. % in water were studied. The simulations of solid liquid suspensions in the stirred vessels were performed by using fully predictive approaches. Eulerian multiphase models were adopted for modelling the solid liquid flow, coupled with three different extensions of the standard k-ɛ model to the case of multiphase flows. The simulated particle axial concentration profiles are compared with experimental data and critically discussed. The most successful simulation strategy and one possible implementation are described.

  1. 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.

  2. 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.

  3. Comparison of two methods for designing calorimeters using stirred tank reactors.

    PubMed

    Regestein, Lars; Giese, Heiner; Zavrel, Michael; Büchs, Jochen

    2013-01-01

    Calorimetry is a robust method for online monitoring and controlling bioprocesses in stirred tank reactors. Up to now, reactor calorimeters have not been optimally constructed for pilot scale applications. Thus, the objective of this paper is to compare two different ways for designing reactor calorimeters and validate them. The "heat capacity" method based on the mass flow of the cooling liquid in the jacket was compared with the "heat transfer" method based on the heat transfer coefficient continuously measured in the cultivation of Escherichia coli VH33 in a 50 L stirred tank reactor. It was found that the values of the "heat transfer" method agreed very well with the calculated values from the oxygen consumption. By contrast, the curve of the "heat capacity" method deviated from that of the oxygen consumption calculated with the oxycaloric equivalent. In conclusion, the "heat transfer" method has been proven to have a higher degree of validity than the "heat capacity" method. Thus, it is a better and more robust means to measure heat generation of fermentations in stirred tank bioreactors on a pilot scale.

  4. 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.

  5. A new microfluidic concept for parallel operated milliliter-scale stirred tank bioreactors.

    PubMed

    Gebhardt, Gabi; Hortsch, Ralf; Kaufmann, Klaus; Arnold, Matthias; Weuster-Botz, Dirk

    2011-01-01

    Parallel miniaturized stirred tank bioreactors are an efficient tool for "high-throughput bioprocess design." As most industrial bioprocesses are pH-controlled and/or are operated in a fed-batch mode, an exact scale-down of these reactions with continuous dosing of fluids into the miniaturized bioreactors is highly desirable. Here, we present the development, characterization, and application of a novel concept for a highly integrated microfluidic device for a bioreaction block with 48 parallel milliliter-scale stirred tank reactors (V = 12 mL). The device consists of an autoclavable fluidic section to dispense up to three liquids individually per reactor. The fluidic section contains 144 membrane pumps, which are magnetically driven by a clamped-on actuator section. The micropumps are designed to dose 1.6 μL per pump lift. Each micropump enables a continuous addition of liquid with a flow rate of up to 3 mL h(-1) . Viscous liquids up to a viscosity of 8.2 mPa s (corresponds to a 60% v/v glycerine solution) can be pumped without changes in the flow rates. Thus, nearly all feeding solutions can be delivered, which are commonly used in bioprocesses. The functionality of the first prototype of this microfluidic device was demonstrated by double-sided pH-controlled cultivations of Saccharomyces cerevisiae based on signals of fluorimetric sensors embedded at the bottom of the bioreactors. Furthermore, fed-batch cultivations with constant and exponential feeding profiles were successfully performed. Thus, the presented novel microfluidic device will be a useful tool for parallel and, thus, efficient optimization of controlled fed-batch bioprocesses in small-scale stirred tank bioreactors. This can help to reduce bioprocess development times drastically.

  6. Cultivation of microplantlets derived from the marine red alga Agardhiella subulata in a stirred tank photobioreactor.

    PubMed

    Huang, Yao-Ming; Rorrer, Gregory L

    2003-01-01

    Macrophytic marine red algae are a diverse source of bioactive natural compounds. "Microplantlet" suspension cultures established from red algae are potential platforms for biosynthesis of these compounds, provided suitable bioreactor configurations for mass culture can be identified. The stirred tank bioreactor offers high rates of gas-liquid mass transfer, which may facilitate the delivery of the CO(2) in the aeration gas to the phototrophic microplantlet suspension culture. Therefore, the effects of impeller speed and CO(2) delivery on the long-term production of microplantlet biomass of the model red alga Agardhiella subulata was studied within a stirred tank photobioreactor equipped with a paddle blade impeller (D(i)/D(T) = 0.5). Nutrient medium replacement was required for sustained biomass production, and the biomass yield coefficient based on nitrate consumption was 1.08 +/- 0.09 g dry biomass per mmol N consumed. Biomass production went through two exponential phases of growth, followed by a CO(2) delivery limited growth phase. The CO(2)-limited growth phase was observed only if the specific growth rate in the second exponential phase of growth was at least 0.03 day(-)(1), the CO(2) delivery rate was less than 0.258 mmol CO(2) L(-)(1) culture h(-)(1), and the plantlet density was at least 10 g fresh mass L(-)(1). Increasing the aeration gas CO(2) partial pressure from 0.00035 to 0.0072 atm decreased the cultivation pH from 8.8 to 7.8, prolonged the second exponential phase of growth by increasing the CO(2) delivery rate, and also increased the photosynthetic oxygen evolution rate. Impeller speeds ranging from 60 to 250 rpm, which generated average shear rates of 2-10 s(-)(1), did not have a significant effect on biomass production rate. However, microplantlets cultivated in a stirred tank bioreactor ultimately assumed compact spherical shape, presumably to minimize exposure to hydrodynamic stress.

  7. Measuring carbon monoxide gas-liquid mass transfer in a stirred tank reactor for syngas fermentation.

    PubMed

    Riggs, Seth S; Heindel, Theodore J

    2006-01-01

    Carbon monoxide-liquid mass transfer rates in a water-filled stirred tank reactor are determined using a myoglobin protein method to measure dissolved carbon monoxide concentrations as a function of time. Data are acquired over a range of stirrer speeds (200 < or = N < or = 600 rpm) and gas flow rates (1 < or = Q < or = 6 L/min), corresponding to a gas retention time range of 1.2-7 min. Volumetric CO-water mass transfer coefficients range from 0.003 to 0.043 s(-1) and are well-correlated using the power density and the superficial gas velocity.

  8. 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. PMID:25635665

  9. 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.

  10. 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.

  11. A simple eccentric stirred tank mini-bioreactor: mixing characterization and mammalian cell culture experiments.

    PubMed

    Bulnes-Abundis, David; Carrillo-Cocom, Leydi M; Aráiz-Hernández, Diana; García-Ulloa, Alfonso; Granados-Pastor, Marisa; Sánchez-Arreola, Pamela B; Murugappan, Gayathree; Alvarez, Mario M

    2013-04-01

    In industrial practice, stirred tank bioreactors are the most common mammalian cell culture platform. However, research and screening protocols at the laboratory scale (i.e., 5-100 mL) rely primarily on Petri dishes, culture bottles, or Erlenmeyer flasks. There is a clear need for simple-easy to assemble, easy to use, easy to clean-cell culture mini-bioreactors for lab-scale and/or screening applications. Here, we study the mixing performance and culture adequacy of a 30 mL eccentric stirred tank mini-bioreactor. A detailed mixing characterization of the proposed bioreactor is presented. Laser induced fluorescence (LIF) experiments and computational fluid dynamics (CFD) computations are used to identify the operational conditions required for adequate mixing. Mammalian cell culture experiments were conducted with two different cell models. The specific growth rate and the maximum cell density of Chinese hamster ovary (CHO) cell cultures grown in the mini-bioreactor were comparable to those observed for 6-well culture plates, Erlenmeyer flasks, and 1 L fully instrumented bioreactors. Human hematopoietic stem cells were successfully expanded tenfold in suspension conditions using the eccentric mini-bioreactor system. Our results demonstrate good mixing performance and suggest the practicality and adequacy of the proposed mini-bioreactor.

  12. Economic comparison of diagnostic antibody production in perfusion stirred tank and in hollow fiber bioreactor processes.

    PubMed

    Vermasvuori, Raisa; Hurme, Markku

    2011-01-01

    The total operating costs of small-scale monoclonal antibody production were calculated for two different upstream options and general downstream procedure based on protein A chromatography. The upstream options were a spin-filter equipped stirred-tank bioreactor (STR) and a hollow fiber bioreactor (HFB). Both the bioreactors were operated in perfusion mode. The total operating costs of the processes were 6,900 €/g for STR option and 6,400 €/g for the HFB option. In the both systems, the costs were dominated by expenses derived from the downstream section (almost 80%) that was almost identical in the both systems. In the upstream section, the investment depreciation was the largest cost item. The lower total costs of the HFB option were a result of lower investment costs and more concentrated product that led into savings also in downstream section. This study brings out the HFB as on viable alternative for stirred-tank bioreactor, especially in small-scale diagnostic monoclonal antibody production. PMID:21954092

  13. A simple eccentric stirred tank mini-bioreactor: mixing characterization and mammalian cell culture experiments.

    PubMed

    Bulnes-Abundis, David; Carrillo-Cocom, Leydi M; Aráiz-Hernández, Diana; García-Ulloa, Alfonso; Granados-Pastor, Marisa; Sánchez-Arreola, Pamela B; Murugappan, Gayathree; Alvarez, Mario M

    2013-04-01

    In industrial practice, stirred tank bioreactors are the most common mammalian cell culture platform. However, research and screening protocols at the laboratory scale (i.e., 5-100 mL) rely primarily on Petri dishes, culture bottles, or Erlenmeyer flasks. There is a clear need for simple-easy to assemble, easy to use, easy to clean-cell culture mini-bioreactors for lab-scale and/or screening applications. Here, we study the mixing performance and culture adequacy of a 30 mL eccentric stirred tank mini-bioreactor. A detailed mixing characterization of the proposed bioreactor is presented. Laser induced fluorescence (LIF) experiments and computational fluid dynamics (CFD) computations are used to identify the operational conditions required for adequate mixing. Mammalian cell culture experiments were conducted with two different cell models. The specific growth rate and the maximum cell density of Chinese hamster ovary (CHO) cell cultures grown in the mini-bioreactor were comparable to those observed for 6-well culture plates, Erlenmeyer flasks, and 1 L fully instrumented bioreactors. Human hematopoietic stem cells were successfully expanded tenfold in suspension conditions using the eccentric mini-bioreactor system. Our results demonstrate good mixing performance and suggest the practicality and adequacy of the proposed mini-bioreactor. PMID:23124589

  14. 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. PMID:26417848

  15. 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

  16. A new halogen-free chemical oscillator: the reaction between permanganate ion and ninhydrin in a continuously stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Treindl, Ľudovít; Nagy, Arpád

    1987-07-01

    The reaction between permanganate ion and ninhydrin in the presence of phosphoric acid in aqueous solution shows sustained oscillations in a continuously stirred tank reactor (CSTR). It exhibits a kinetic bistability between an oscillatory and a stationary state. Our new oscillating system seems to be a second permanganate chemical oscillator, thus broadening the small group of non-halogen-based chemical oscillators.

  17. Growth of Saccharomycopsis fibuligera in a continuous-stirred-tank fermentor

    SciTech Connect

    Admassu, W.; Korus, R.A.; Heimsch, R.C.; Lemmel, S.A.

    1981-10-01

    Growth rates and amylase production rates were determined for the yeast Saccharomycopsis fibuligera grown on a simulated potato processing waste in a continuous-stirred-tank fermentor. Saccharomycopsis fibuligera formed large multicellular flocs in the fermentor, and cell growth was reduced at low dilution rates because of mass-transfer resistance. The average Thiele modulus, which is the measure of extent of substrate diffusion, had a value ranging from phi (average) = 2.2 for D = 0.10 to 0.3 for D = 0.40. Growth rates were described by the Monod equation modified to include mass-transfer effects. This modified Monod equation was used to predict growth rates from measured floc-size distribution. Experimentally determined growth rates were in close agreement with these predicted values. (Refs. 21).

  18. 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.

  19. Non-invasive online detection of microbial lysine formation in stirred tank bioreactors by using calorespirometry.

    PubMed

    Regestein, Lars; Maskow, Thomas; Tack, Andreas; Knabben, Ingo; Wunderlich, Martin; Lerchner, Johannes; Büchs, Jochen

    2013-05-01

    Non-invasive methods for online monitoring of biotechnological processes without compromising the integrity of the reactor system are very important to generate continuous data. Even though calorimetry has been used in conventional biochemical analysis for decades, it has not yet been specifically applied for online detection of product formation at technical scale. Thus, this article demonstrates a calorespirometric method for online detection of microbial lysine formation in stirred tank bioreactors. The respective heat generation of two bacterial strains, Corynebacterium glutamicum ATCC 13032 (wild-type) and C. glutamicum DM1730 (lysine producer), was compared with the O2 -consumption in order to determine whether lysine was formed. As validation of the proposed calorespirometric method, the online results agreed well with the offline measured data. This study has proven that calorespirometry is a viable non-invasive technique to detect product formation at any time point.

  20. 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.

  1. An approximate solution for a transient two-phase stirred tank bioreactor with nonlinear kinetics.

    PubMed

    Valdés-Parada, Francisco J; Alvarez-Ramírez, José; Ochoa-Tapia, J Alberto

    2005-01-01

    The derivation of an approximate solution method for models of a continuous stirred tank bioreactor where the reaction takes place in pellets suspended in a well-mixed fluid is presented. It is assumed that the reaction follows a Michaelis-Menten-type kinetics. Analytic solution of the differential equations is obtained by expanding the reaction rate expression at pellet surface concentration using Taylor series. The concept of a pellet's dead zone is incorporated; improving the predictions and avoiding negative values of the reagent concentration. The results include the concentration expressions obtained for (a) the steady state, (b) the transient case, imposing the quasi-steady-state assumption for the pellet equation, and (c) the complete solution of the approximate transient problem. The convenience of the approximate method is assessed by comparison of the predictions with the ones obtained from the numerical solution of the original problem. The differences are in general quite acceptable.

  2. Modeling of organic pollutant destruction in a stirred-tank reactor by ozonation.

    PubMed

    Cheng, J; Yang, Z R; Chen, H Q; Kuo, C H; Zappi, E M

    2001-10-01

    Destruction of organic contaminants in water by ozonation is a gas-liquid process which involves ozone mass transfer and fast irreversible chemical reactions. Ozonation reactor design and process optimizing require the modeling of the gas-liquid interactions within the reactor. In this paper a theoretical model combining the fluid dynamic and reaction kinetic parameters is proposed for predicting the destruction rates of organic pollutants in a semi-batch stirred-tank reactor by ozonation. A simple expression for the enhancement factor as our previous work has been applied to evaluate the chemical mass transfer coefficient in ozone absorption, 2,4-dichlorophenol (2,4-DCP) and 2,6-DCP or their mixture are chosen as the model compounds for simulating, and the predicted DCP concentrations are compared with some measured data.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Completely stirred tank reactor behavior in an unmixed anaerobic digester: the induced bed reactor.

    PubMed

    Dustin, J Shaun; Hansen, Conly L

    2012-09-01

    The induced bed reactor (IBR) was developed to apply high-rate anaerobic digestion techniques to high suspended solids substrates (6 to 12% total solids). This technology has been implemented at multiple full-scale installations in the United States and Canada. Residence time distribution studies for 58-L laboratory-scale reactors operated at a 3.8-day hydraulic retention time were conducted at 35, 45, and 55 degrees C under control and active digestion conditions. Rhodamine WT and lithium ion were used as tracers. The results show that the IBR most closely approximated completely stirred tank reactor behavior when operated under the study conditions. Mixing was likely a result of a (1) combination of energy inputs from thermal gradients induced by heat flux through the reactors, and (2) shear induced by gas evolution in the sludge bed. PMID:23012770

  8. Numerical Simulation of Three-dimensional Flow Field in Quadrate Stirred Tanks

    NASA Astrophysics Data System (ADS)

    Wu, Y. B.; Feng, W.

    In the paper based on the Computational Fluid Dynamics (CFD) method three-dimensional flow fields are studied using FLUENT software. Sliding mesh method, RNG к - ɛ turbulent model and second-order upwind difference scheme are used to perform the numerical simulation. Firstly, the prediction capabilities of the turbulence models used in the simulation are assessed in detail. Secondly, numerical study is focused on the velocity field of an actual quadrate stirred tank with a dual 45 degrees pitched four-blade turbine in given conditions of design and operation parameters. Finally, the influences of design and operation parameters on mixing effects are analyzed by the simulation of the turbulence intensity. The study provides reference aids for optimization of design and operation parameters.

  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. 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.

  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

    2013-01-01

    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

  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. Prediction of gas-liquid mass transfer coefficient in sparged stirred tank bioreactors.

    PubMed

    Garcia-Ochoa, Felix; Gomez, Emilio

    2005-12-20

    Oxygen mass transfer in sparged stirred tank bioreactors has been studied. The rate of oxygen mass transfer into a culture in a bioreactor is affected by operational conditions and geometrical parameters as well as the physicochemical properties of the medium (nutrients, substances excreted by the micro-organism, and surface active agents that are often added to the medium) and the presence of the micro-organism. Thus, oxygen mass transfer coefficient values in fermentation broths often differ substantially from values estimated for simple aqueous solutions. The influence of liquid phase physicochemical properties on kLa must be divided into the influence on k(L) and a, because they are affected in different ways. The presence of micro-organisms (cells, bacteria, or yeasts) can affect the mass transfer rate, and thus kLa values, due to the consumption of oxygen for both cell growth and metabolite production. In this work, theoretical equations for kLa prediction, developed for sparged and stirred tanks, taking into account the possible oxygen mass transfer enhancement due to the consumption by biochemical reactions, are proposed. The estimation of kLa is carried out taking into account a strong increase of viscosity broth, changes in surface tension and different oxygen uptake rates (OURs), and the biological enhancement factor, E, is also estimated. These different operational conditions and changes in several variables are performed using different systems and cultures (xanthan aqueous solutions, xanthan production cultures by Xanthomonas campestris, sophorolipids production by Candida bombicola, etc.). Experimental and theoretical results are presented and compared, with very good results.

  14. 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

  15. Solubilization of Trace Metals from FGD Gypsum Using a Continuously Stirred Tank Reactor

    SciTech Connect

    Kairies, C.L.; Schroeder, K.T.; Thompson, R.L.; Cardone, C.R.; Rohar, P.C.

    2007-07-01

    A continuous, stirred-tank extractor (CSTX) is an effective technique for evaluating the leachability of contaminants from flue gas desulfurization (FGD) products and other materials with low permeability or cementitious properties and allows the chemistry of the leaching process to be studied at a level unachievable through more traditional batch and column techniques. In this study, metal release patterns were examined in detail over a range of pH values extending from the material’s natural, slightly alkaline pH to acidic pH conditions. Understanding the fundamental mechanisms operating during the leaching process provides a basis for evaluating the safety of FGD byproducts and ensuring these materials are used and disposed of appropriately. The results indicate that the leaching behavior of individual elements depends on several factors including, but not limited to, the solubility of the mineral phases present, sorption properties of the remaining phases, behavior of the solubilized material in the tank, the type of species in solution and the neutralization capacity of the minerals. Bulk gypsum is moderately soluble; dissolution is controlled by its solubility product and hydration reactions rather than pH. Elution and pH profiles indicate the presence of alkaline material(s) that buffer the system during the initial leaching. Iron and aluminum are not leached until the buffering capacity is exhausted. Any elements bound to these phases can be mobilized during this dissolution. Arsenic, lead and mercury are not released during the leaching of most samples and become concentrated in a minor, insoluble residue remaining at the end of each experiment

  16. 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.

  17. 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.

  18. Biodegradation of high concentrations of benzene vapors in a two phase partition stirred tank bioreactor.

    PubMed

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

    2013-01-15

    The present study examined the biodegradation rate of benzene vapors in a two phase stirred tank bioreactor by a bacterial consortium obtained from wastewater of an oil industry refinery house. Initially, the ability of the microbial consortium for degrading benzene was evaluated before running the bioreactor. The gaseous samples from inlet and outlet of bioreactor were directly injected into a gas chromatograph to determine benzene concentrations. Carbone oxide concentration at the inlet and outlet of bioreactor were also measured with a CO2 meter to determine the mineralization rate of benzene. Influence of the second non-aqueous phase (silicon oil) has been emphasized, so at the first stage the removal efficiency (RE) and elimination capacity (EC) of benzene vapors were evaluated without any organic phase and in the second stage, 10% of silicon oil was added to bioreactor media as an organic phase. Addition of silicon oil increased the biodegradation performance up to an inlet loading of 5580 mg/m3, a condition at which, the elimination capacity and removal efficiency were 181 g/m3/h and 95% respectively. The elimination rate of benzene increased by 38% in the presence of 10% of silicone oil. The finding of this study demonstrated that two phase partition bioreactors (TPPBs) are potentially effective tools for the treatment of gas streams contaminated with high concentrations of poorly water soluble organic contaminant, such as benzene.

  19. Enhanced production of recombinant aspartase of Aeromonas media NFB-5 in a stirred tank reactor.

    PubMed

    Singh, Ram Sarup; Yadav, Mukesh

    2013-10-01

    Aspartase gene (aspA) from Aeromonas media NFB-5 was cloned and expressed in Escherichia coli BL21 using pET21b(+) expression vector. Maximum production of aspartase was obtained at shake-flask after 5 h of IPTG (1.5 mM) induction at 37°C and by supplementing the media with KH2PO4 (0.3%, w/v) and K2HPO4 (0.3%, w/v). Further production was investigated at a laboratory scale stirred tank reactor using response surface methodology (RSM). Agitation (130-270 rpm), aeration (0.30-1.70 vvm) and IPTG induction time (3-7 h) was optimized. Optimal levels of agitation (250 rpm), aeration (1.25 vvm) and induction time (6h) were determined by statistical analysis of the experimental data. More than 7-fold increase in recombinant aspartase (1234 U/g wet weight) was observed than the parent strain (172 U/g wet wt). Homogenized immobilized permeabilized recombinant cells (566 mg/g wet cells) produced more L-aspartic acid as compared to permeabilized recombinant free cells (154 mg/g wet cells).

  20. [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.

  1. 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.

  2. A model for treating polluted air streams in a continuous two liquid phase stirred tank bioreactor.

    PubMed

    Fazaelipoor, Mohammad Hassan

    2007-09-01

    Biological air treatment systems have been widely under investigation in recent years. Inclusion of non-biodegradable organic solvents to these systems is a way to improve the biotic removal capacity of the systems. In this article the process of absorption and biodegradation of a hydrophobic organic compound in a two liquid phase stirred tank bioreactor has been modeled. Using the model it has been shown that the inclusion of an organic solvent is advantageous if certain conditions are met. Some simulation examples showed that the usefulness of adding an organic solvent to the system depends on kinetic parameters of biological reactions and mass transfer coefficients of pollutants and oxygen between the air and liquid phases. Since different factors influence the process, the usefulness of including an organic solvent to the system should be checked in each special case. The simple model presented in this article can help the prediction of the effect of amending a solvent to the bioreactor under a set of given conditions.

  3. Bacterial monitoring by molecular tools of a continuous stirred tank reactor treating textile wastewater.

    PubMed

    Khelifi, Eltaief; Bouallagui, Hassib; Touhami, Youssef; Godon, Jean-Jacques; Hamdi, Moktar

    2009-01-01

    This study was performed to examine the effect of the bacterial diversity changes on the performances of a continuously stirred tank reactor (CSTR) treating textile wastewater. The molecular fingerprint established using polymerase chain reaction-single stranded conformation polymorphism (PCR-SSCP) methods showed that bacterial community profiles changed simultaneously with the increase of the wastewater loading rates (WLR). For the two WLR of 0.28 g l(-1)d(-1) and 0.37 g l(-1)d(-1), the reactor maintained good performances, suggesting that the large bacterial community present a high specific activity. The increase of the WLR from 0.37 to 1.12 g l(-1)d(-1) decreased the colour and the chemical oxygen demand (COD) removal efficiencies from 90% to 55% and from 85% to 30%, respectively, explained by the decrease of the bacterial diversity and activity. The changes of the bacterial dominance had no affect on the reactor performances. However, the decrease of the bacterial diversity significantly affected the colour and the COD removal efficiencies. It should conclude that indigo dye-containing textile wastewater treatment required the concerted activity of multiple bacterial populations.

  4. 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.

  5. Improvement of foam breaking and oxygen-transfer performance in a stirred-tank fermenter.

    PubMed

    Takesono, Satoshi; Onodera, Masayuki; Toda, Kiyoshi; Yoshida, Masanori; Yamagiwa, Kazuaki; Ohkawa, Akira

    2006-03-01

    This study examined a stirred-tank fermenter (STF) containing low-viscosity foaming liquids with an agitation impeller and foam-breaking impeller mounted on the same shaft. Results showed that the performance of the foam-breaking impeller can be improved by changing a conventional six-blade turbine impeller into a rod impeller as the agitation impeller. The volumetric oxygen-transfer coefficient, kLa, in the mechanical foam-control method (MFM) using a six-blade vaned disk as the foam-breaking impeller in the STF with the rod impeller was approximately five times greater than that of the chemical foam-control method (CFM) adding an anti-foaming agent in the STF with the six-blade turbine impeller. Application of the present method to the cultivation of Saccharomyces cerevisiae K-7 demonstrated that the cultivation time up to the maximum cell concentration was remarkably shorter than that achieved using a conventional CFM. PMID:16208498

  6. 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.

  7. Production of halophilic proteins using Haloferax volcanii H1895 in a stirred-tank bioreactor.

    PubMed

    Strillinger, Eva; Grötzinger, Stefan Wolfgang; Allers, Thorsten; Eppinger, Jörg; Weuster-Botz, Dirk

    2016-02-01

    The success of biotechnological processes is based on the availability of efficient and highly specific biocatalysts, which can satisfy industrial demands. Extreme and remote environments like the deep brine pools of the Red Sea represent highly interesting habitats for the discovery of novel halophilic and thermophilic enzymes. Haloferax volcanii constitutes a suitable expression system for halophilic enzymes obtained from such brine pools. We developed a batch process for the cultivation of H. volcanii H1895 in controlled stirred-tank bioreactors utilising knockouts of components of the flagella assembly system. The standard medium Hv-YPC was supplemented to reach a higher cell density. Without protein expression, cell dry weight reaches 10 g L(-1). Two halophilic alcohol dehydrogenases were expressed under the control of the tryptophanase promoter p.tna with 16.8 and 3.2 mg gCDW (-1), respectively, at a maximum cell dry weight of 6.5 g L(-1). Protein expression was induced by the addition of L-tryptophan. Investigation of various expression strategies leads to an optimised two-step induction protocol introducing 6 mM L-tryptophan at an OD650 of 0.4 followed by incubation for 16 h and a second induction step with 3 mM L-tryptophan followed by a final incubation time of 4 h. Compared with the uncontrolled shaker-flask cultivations used until date, dry cell mass concentrations were improved by a factor of more than 5 and cell-specific enzyme activities showed an up to 28-fold increased yield of the heterologous proteins.

  8. Shear conditions in clavulanic acid production by Streptomyces clavuligerus in stirred tank and airlift bioreactors.

    PubMed

    Cerri, M O; Badino, A C

    2012-08-01

    In biochemical processes involving filamentous microorganisms, the high shear rate may damage suspended cells leading to viability loss and cell disruption. In this work, the influence of the shear conditions in clavulanic acid (CA) production by Streptomyces clavuligerus was evaluated in a 4-dm(3) conventional stirred tank (STB) and in 6-dm(3) concentric-tube airlift (ALB) bioreactors. Batch cultivations were performed in a STB at 600 and 800 rpm and 0.5 vvm (cultivations B1 and B2) and in ALB at 3.0 and 4.1 vvm (cultivations A1 and A2) to define two initial oxygen transfer conditions in both bioreactors. The average shear rate ([Formula: see text]) of the cultivations was estimated using correlations of recent literature based on experimental data of rheological properties of the broth (consistency index, K, and flow index, n) and operating conditions, impeller speed (N) for STB and superficial gas velocity in the riser (UGR) for ALB. In the same oxygen transfer condition, the [Formula: see text] values for ALB were higher than those obtained in STB. The maximum [Formula: see text] presented a strong correlation with a maximum consistency index (K (max)) of the broth. Close values of maximum CA production were obtained in cultivations A1 and A2 (454 and 442 mg L(-1)) with similar maximum [Formula: see text] values of 4,247 and 4,225 s(-1). In cultivations B1 and B2, the maximum CA production of 269 and 402 mg L(-1) were reached with a maximum [Formula: see text] of 904 and 1,786 s(-1). The results show that high values of average shear rate increase the CA production regardless of the oxygen transfer condition and bioreactor model.

  9. The nonequilibrium electromotive force. II. Theory for a continuously stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Keizer, Joel

    1987-10-01

    In previous work [J. Keizer, J. Chem. Phys. 82, 2751 (1985)] we used statistical nonequilibrium thermodynamics to predict a non-Nernstian component to the electromotive force (EMF) for half-reactions involving reactants at nonequilibrium steady states. In this paper we present a simple theory for calculating the nonequilibrium component of the EMF based on the elementary transport processes occurring in a continuously stirred tank reactor (CSTR). The calculations utilize the density-density correlation function, which is obtained from the statistical theory of nonequilibrium thermodynamics. This gives rise to an expression for the second partial derivatives of the generalized entropy, or sigma function, which is used to calculate generalized chemical potentials. The generalized chemical potentials are related to the EMF through a generalization of the Nernst equation. The calculations presented here depend on the residence time in the CSTR, reaction rate constants, feed line concentrations in the CSTR, and the diffusion constants of reactants and products. A characteristic diffusion length is used to represent the length scale below which turbulent mixing effects are not important. Calculations with the theory are carried out for several different reaction mechanisms, including A+B⇄C; A+B⇄C, D+E⇄B; A+B⇄2B; and A+B→C+D, A+D→C+E. Values of the nonequilibrium EMF depend on the mechanism as well as all of the transport parameters cited above. For a plausible choice of the diffusion length, corrections to the Nernst formula can be as large as 10-15 mV. Specific calculations for the reaction of Fe2+ with S2O2-8 are shown in the preceding paper to agree with experimental measurements on this system in a CSTR.

  10. 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.

  11. 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.

  12. Application of LIF to investigate gas transfer near the air-water interface in a grid-stirred tank

    NASA Astrophysics Data System (ADS)

    Herlina; Jirka, G. H.

    The interaction between oxygen absorption into liquids and bottom shear-induced turbulence was investigated in a grid-stirred tank using a laser-induced fluorescence (LIF) technique. The LIF technique enabled visualization as well as quantification of planar concentration fields of the dissolved oxygen (DO) near the air-water interface. Qualitative observation of the images provided more insight into the physical mechanism controlling the gas transfer process. The high data resolution is an advantage for revealing the concentration distribution within the boundary layer, which is a few hundreds of a micrometer thick. Mean and turbulent fluctuation characteristics were obtained and compared with previous results.

  13. 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.

  14. Perfusion Stirred-Tank Bioreactors for 3D Differentiation of Human Neural Stem Cells.

    PubMed

    Simão, Daniel; Arez, Francisca; Terasso, Ana P; Pinto, Catarina; Sousa, Marcos F Q; Brito, Catarina; Alves, Paula M

    2016-01-01

    Therapeutic breakthroughs in neurological disorders have been hampered by the lack of accurate central nervous system (CNS) models. The development of these models allows the study of the disease onset/progression mechanisms and the preclinical evaluation of new therapeutics. This has traditionally relied on genetically engineered animal models that often diverge considerably from the human phenotype (developmental, anatomic, and physiological) and 2D in vitro cell models, which fail to recapitulate the characteristics of the target tissue (cell-cell and cell-matrix interactions, cell polarity, etc.). Recapitulation of CNS phenotypic and functional features in vitro requires the implementation of advanced culture strategies, such as 3D culture systems, which enable to mimic the in vivo structural and molecular complexity. Models based on differentiation of human neural stem cells (hNSC) in 3D cultures have great potential as complementary tools in preclinical research, bridging the gap between human clinical studies and animal models. The development of robust and scalable processes for the 3D differentiation of hNSC can improve the accuracy of early stage development in preclinical research. In this context, the use of software-controlled stirred-tank bioreactors (STB) provides an efficient technological platform for hNSC aggregation and differentiation. This system enables to monitor and control important physicochemical parameters for hNSC culture, such as dissolved oxygen. Importantly, the adoption of a perfusion operation mode allows a stable flow of nutrients and differentiation/neurotrophic factors, while clearing the toxic by-products. This contributes to a setting closer to the physiological, by mimicking the in vivo microenvironment. In this chapter, we address the technical requirements and procedures for the implementation of 3D differentiation strategies of hNSC, by operating STB under perfusion mode for long-term cultures. This strategy is suitable

  15. Perfusion Stirred-Tank Bioreactors for 3D Differentiation of Human Neural Stem Cells.

    PubMed

    Simão, Daniel; Arez, Francisca; Terasso, Ana P; Pinto, Catarina; Sousa, Marcos F Q; Brito, Catarina; Alves, Paula M

    2016-01-01

    Therapeutic breakthroughs in neurological disorders have been hampered by the lack of accurate central nervous system (CNS) models. The development of these models allows the study of the disease onset/progression mechanisms and the preclinical evaluation of new therapeutics. This has traditionally relied on genetically engineered animal models that often diverge considerably from the human phenotype (developmental, anatomic, and physiological) and 2D in vitro cell models, which fail to recapitulate the characteristics of the target tissue (cell-cell and cell-matrix interactions, cell polarity, etc.). Recapitulation of CNS phenotypic and functional features in vitro requires the implementation of advanced culture strategies, such as 3D culture systems, which enable to mimic the in vivo structural and molecular complexity. Models based on differentiation of human neural stem cells (hNSC) in 3D cultures have great potential as complementary tools in preclinical research, bridging the gap between human clinical studies and animal models. The development of robust and scalable processes for the 3D differentiation of hNSC can improve the accuracy of early stage development in preclinical research. In this context, the use of software-controlled stirred-tank bioreactors (STB) provides an efficient technological platform for hNSC aggregation and differentiation. This system enables to monitor and control important physicochemical parameters for hNSC culture, such as dissolved oxygen. Importantly, the adoption of a perfusion operation mode allows a stable flow of nutrients and differentiation/neurotrophic factors, while clearing the toxic by-products. This contributes to a setting closer to the physiological, by mimicking the in vivo microenvironment. In this chapter, we address the technical requirements and procedures for the implementation of 3D differentiation strategies of hNSC, by operating STB under perfusion mode for long-term cultures. This strategy is suitable

  16. 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.

  17. 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).

  18. 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.

  19. The effect of hydrodynamic stress on the growth of Xanthomonas campestris cultures in a stirred and sparged tank bioreactor.

    PubMed

    Garcia-Ochoa, F; Gomez, E; Alcon, A; Santos, V E

    2013-07-01

    The specific growth and the xanthan production rates by the bacterium Xanthomonas campestris under different shear levels in shake flasks and in a stirred and sparged tank bioreactor have been studied. The shake flask has been used as a reference for studying the shear effects. An effectiveness factor expressed by the ratio of the observed growth rate and the growth rate without oxygen limitation or cell damage was calculated in both modes of cultures. It was observed that the effectiveness factor was strongly dependent on the operational conditions. A strong oxygen transfer limitation at low stirring rates, indicated by a 54 % decrease in the effectiveness factor was observed. In contrast, at higher stirrer speed, cell damage was caused by hydrodynamic stress in the turbulent bulk of the broth, yielding again a decrease in the effectiveness factor values for stirrer speeds higher than 500 rpm. Cell morphological changes were also observed depending on the agitation conditions, differences in morphology being evident at high shear stress.

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. 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. PMID:23046698

  5. 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.

  6. 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. PMID:27591517

  7. Biohydrogen production in a continuous stirred tank bioreactor from synthesis gas by anaerobic photosynthetic bacterium: Rhodopirillum rubrum.

    PubMed

    Younesi, Habibollah; Najafpour, Ghasem; Ku Ismail, Ku Syahidah; Mohamed, Abdul Rahman; Kamaruddin, Azlina Harun

    2008-05-01

    Hydrogen may be considered a potential fuel for the future since it is carbon-free and oxidized to water as a combustion product. Bioconversion of synthesis gas (syngas) to hydrogen was demonstrated in continuous stirred tank bioreactor (CSTBR) utilizing acetate as a carbon source. An anaerobic photosynthetic bacterium, Rhodospirillum rubrum catalyzed water-gas shift reaction which was applied for the bioconversion of syngas to hydrogen. The continuous fermentation of syngas in the bioreactor was continuously operated at various gas flow rates and agitation speeds, for the period of two months. The gas flow rates were varied from 5 to 14 ml/min. The agitation speeds were increasingly altered in the range of 150-500 rpm. The pH and temperature of the bioreactor was set at 6.5 and 30 degrees C. The liquid flow rate was kept constant at 0.65 ml/min for the duration of 60 days. The inlet acetate concentration was fed at 4 g/l into the bioreactor. The hydrogen production rate and yield were 16+/-1.1 mmol g(-1)cell h(-1) and 87+/-2.4% at fixed agitation speed of 500 rpm and syngas flow rate of 14 ml/min, respectively. The mass transfer coefficient (KLa) at this condition was approximately 72.8h(-1). This new approach, using a biocatalyst was considered as an alternative method of conventional Fischer-Tropsch synthetic reactions, which were able to convert syngas into hydrogen.

  8. Decolourization of anaerobically digested and polyaluminium chloride treated distillery spentwash in a fungal stirred tank aerobic reactor.

    PubMed

    Singh, S S; Dikshit, A K

    2011-11-01

    Decolourization of anaerobically digested and polyaluminium chloride treated distillery spentwash was studied in a fungal stirred tank aerobic reactor without dilution of wastewater. Aspergillus niger isolate IITB-V8 was used as the fungal inoculum. The main objectives of the study were to optimize the stirrer speed for achieving maximum decolourization and to determine the kinetic parameters. A mathematical model was developed to describe the batch culture kinetics. Volumetric oxygen transfer coefficient (k (L) a) was obtained using dynamic method. The maximum specific growth rate and growth yield of fungus were determined using Logistic equation and using Luedeking-Piret equation. 150 rpm was found to be optimum stirrer speed for overall decolourization of 87%. At the optimum stirrer speed, volumetric oxygen transfer coefficient (k (L) a) was 0.4957 min(-1) and the maximum specific growth rate of fungus was 0.224 h(-1). The values of yield coefficient (Y ( x/s)) and maintenance coefficient (m (s)) were found to be 0.48 g cells (g substrate)(-1) and 0.015 g substrate (g cells)(-1) h(-1).

  9. Effect of tryptone and ammonia on the biogas process in continuously stirred tank reactors treating cattle manure.

    PubMed

    Nielsen, H B; Ahring, B K

    2007-08-01

    Two thermophilic continuously stirred tank reactors, R1 and R2, were subject to pulses of tryptone and ammonia. R1 was operated at an ammonia-N concentration of 3.0 g l(-1) and R2 was operated at an ammonia-N concentration of 1.7 g l(-1). Shock loads of tryptone (10 g l(-1), 10 g l(-1), 15 g l(-1)) had an immediate stimulating effect on methanogenesis for both reactors illustrated by significant peaks in methane production but also led to an organic overloading illustrated by a steep increase in volatile fatty acids (VFA) concentration. Three days after the pulses a second peak in acetate concentration and a decrease in methane production indicated an ammonia-inhibition of the acetoclastic methanogens. During the pulses of tryptone the performance of R1 was slightly more affected than R2. Pulses of ammonia (0.79 g l(-1) as N) resulted in a decrease in methane production of both reactors but no immediate increases in VFA concentrations was observed illustrating that the ammonia inhibition during this experiment was an overall inhibition of the biogas process and not only an inhibition of the methanogens.

  10. 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.

  11. 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.

  12. Removal of dichloromethane from waste gases in one- and two-liquid-phase stirred tank bioreactors and biotrickling filters.

    PubMed

    Bailón, Laura; Nikolausz, Marcell; Kästner, Matthias; Veiga, María C; Kennes, Christian

    2009-01-01

    The removal of dichloromethane (DCM) from polluted air was studied both in biotrickling filters and in continuous stirred tank bioreactors, using either a single-liquid aqueous phase or a combination of an aqueous-organic liquid phase. The presence of the organic phase, i.e. silicone oil, at a volume ratio of 10% of the liquid phase, increased the maximum EC by about 25% in the BTF, reaching 200 gm(3)/h, and by as much as 300% in the CSTB, reaching 350 gm(3)/h. Based on data of chloride release in the aqueous phase and carbon dioxide production in the gas phase, complete dechlorination and mineralization of the pollutant could be confirmed. When applying shock loads, a more stable behaviour was observed in the presence of the organic phase. Generally, the completely mixed reactors were also more stable than the plug-flow biotrickling filters, irrespective of the presence of the organic phase. The use of molecular techniques allowed showing that the originally inoculated DCM-degrading Hyphomicrobium strains remained present, although not dominant, after long-term bioreactor operation. Different new bacterial populations did also appear in the systems, some of which were unable to degrade DCM. PMID:18945466

  13. Production of bioethanol by direct bioconversion of oil-palm industrial effluent in a stirred-tank bioreactor.

    PubMed

    Alam, Md Zahangir; Kabbashi, Nassereldeen A; Hussin, S Nahdatul I S

    2009-06-01

    The purpose of this study was to evaluate the feasibility of producing bioethanol from palm-oil mill effluent generated by the oil-palm industries through direct bioconversion process. The bioethanol production was carried out through the treatment of compatible mixed cultures such as Thrichoderma harzianum, Phanerochaete chrysosporium, Mucor hiemalis, and yeast, Saccharomyces cerevisiae. Simultaneous inoculation of T. harzianum and S. cerevisiae was found to be the mixed culture that yielded the highest ethanol production (4% v/v or 31.6 g/l). Statistical optimization was carried out to determine the operating conditions of the stirred-tank bioreactor for maximum bioethanol production by a two-level fractional factorial design with a single central point. The factors involved were oxygen saturation level (pO(2)%), temperature, and pH. A polynomial regression model was developed using the experimental data including the linear, quadratic, and interaction effects. Statistical analysis showed that the maximum ethanol production of 4.6% (v/v) or 36.3 g/l was achieved at a temperature of 32 degrees C, pH of 6, and pO(2) of 30%. The results of the model validation test under the developed optimum process conditions indicated that the maximum production was increased from 4.6% (v/v) to 6.5% (v/v) or 51.3 g/l with 89.1% chemical-oxygen-demand removal.

  14. A comparison of mass transfer coefficients between trickle-bed, hollow fiber membrane and stirred tank reactors.

    PubMed

    Orgill, James J; Atiyeh, Hasan K; Devarapalli, Mamatha; Phillips, John R; Lewis, Randy S; Huhnke, Raymond L

    2013-04-01

    Trickle-bed reactor (TBR), hollow fiber membrane reactor (HFR) and stirred tank reactor (STR) can be used in fermentation of sparingly soluble gasses such as CO and H2 to produce biofuels and bio-based chemicals. Gas fermenting reactors must provide high mass transfer capabilities that match the kinetic requirements of the microorganisms used. The present study compared the volumetric mass transfer coefficient (K(tot)A/V(L)) of three reactor types; the TBR with 3 mm and 6 mm beads, five different modules of HFRs, and the STR. The analysis was performed using O2 as the gaseous mass transfer agent. The non-porous polydimethylsiloxane (PDMS) HFR provided the highest K(tot)A/V(L) (1062 h(-1)), followed by the TBR with 6mm beads (421 h(-1)), and then the STR (114 h(-1)). The mass transfer characteristics in each reactor were affected by agitation speed, and gas and liquid flow rates. Furthermore, issues regarding the comparison of mass transfer coefficients are discussed.

  15. Hydrogen-producing capability of anaerobic activated sludge in three types of fermentations in a continuous stirred-tank reactor.

    PubMed

    Li, Jianzheng; Zheng, Guochen; He, Junguo; Chang, Sheng; Qin, Zhi

    2009-01-01

    A continuous stirred-tank reactor was used as an anaerobic sludge system and the hydrogen production capabilities of three typical fermentations, in terms of specific hydrogen production rates, were investigated under the same hydraulic retention times (8 h) and influent chemical oxygen demand (5000 mg/L) at 35 degrees C. The reactor was continuously fed with diluted molasses, while the pH and oxidation reduction potential in the reactor were regulated to control the type of fermentation. The specific hydrogen production rate of the anaerobic sludge reached 2.96 mol/kg mixed liquid volatile suspended solid (MLVSS)/day, (mol x kg MLVSS(-1) d(-1)), in ethanol-type fermentation, while 0.57 mol x kg MLVSS(-1) d(-1) in butyric acid-type fermentation, and 0.022 mol x kg MLVSS(-1) d(-1) in propionic acid-type fermentation. The hydrogen production capability of ethanol-type fermentation was 4.11 times greater than that of butyric acid-type fermentation and 148 times that of propionic acid-type fermentation.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  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. 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. PMID:26304128

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

    PubMed

    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

  4. 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

  5. A comparison of mass transfer coefficients between trickle-bed, hollow fiber membrane and stirred tank reactors.

    PubMed

    Orgill, James J; Atiyeh, Hasan K; Devarapalli, Mamatha; Phillips, John R; Lewis, Randy S; Huhnke, Raymond L

    2013-04-01

    Trickle-bed reactor (TBR), hollow fiber membrane reactor (HFR) and stirred tank reactor (STR) can be used in fermentation of sparingly soluble gasses such as CO and H2 to produce biofuels and bio-based chemicals. Gas fermenting reactors must provide high mass transfer capabilities that match the kinetic requirements of the microorganisms used. The present study compared the volumetric mass transfer coefficient (K(tot)A/V(L)) of three reactor types; the TBR with 3 mm and 6 mm beads, five different modules of HFRs, and the STR. The analysis was performed using O2 as the gaseous mass transfer agent. The non-porous polydimethylsiloxane (PDMS) HFR provided the highest K(tot)A/V(L) (1062 h(-1)), followed by the TBR with 6mm beads (421 h(-1)), and then the STR (114 h(-1)). The mass transfer characteristics in each reactor were affected by agitation speed, and gas and liquid flow rates. Furthermore, issues regarding the comparison of mass transfer coefficients are discussed. PMID:23434811

  6. 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.

  7. 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.

  8. Combined effect of hydrodynamic and interfacial flow parameters on lysozyme deactivation in a stirred tank bioreactor.

    PubMed

    Ghadge, Rajaram S; Patwardhan, Ashwin W; Joshi, Jyeshtharaj B

    2006-01-01

    The dynamic environment within a bioreactor and in the purification equipment is known to affect the activity and yield of enzyme production. The present research focuses on the effect of hydrodynamic flow parameters (average energy dissipation rate, maximum energy dissipation rate, average shear rate, and average normal stress) and the interfacial flow parameters (specific interfacial area and mass transfer coefficient) on the activity of lysozyme. Flow parameters were estimated using CFD simulation based on the k-epsilon approach. Enzyme deactivation was investigated in 0.1, 0.3, 0.57, and 1 m i.d. vessels. Enzyme solution was subjected to hydrodynamic stress using various types of impellers and impeller combinations over a wide range of power consumption (0.03 < P(G)/V < 7, kW/m3). The effects of tank diameter, impeller diameter, blade width, blade angle, and the number of blades on the extent of deactivation were investigated. At equal value of P(G)/V, epsilon(max), and gamma(avg), the extent of deactivation was dramatically different for different impeller types. The extent of deactivation was found to correlate well with the average turbulent normal stress and the mass transfer coefficient.

  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. Operational strategies for thermophilic anaerobic digestion of organic fraction of municipal solid waste in continuously stirred tank reactors.

    PubMed

    Angelidaki, I; Cui, J; Chen, X; Kaparaju, P

    2006-08-01

    Three operational strategies to reduce inhibition due to ammonia during thermophilic anaerobic digestion of source-sorted organic fraction of municipal solid waste (SS-OFMSW) rich in proteins were investigated. Feed was prepared by diluting SS-OFMSW (ratio of 1:4) with tap water or reactor process water with or without stripping ammonia. Three continuously stirred tank reactors were operated at 55 degrees C with 11.4 gVS d(-1) loading rate and 15 d retention time. Total ammonia nitrogen (TAN) level in the reactor fed with recirculated water alone was spiked to 3.5 and 5.5 g-N l(-1) through ammonium bicarbonate additions. Dilution of SS-OFMSW with fresh water showed a stable performance with volatile fatty acids of < 1g l(-1) and methane yield of 0.40 m3 kg(-1) volatile solids (VS). Use of recirculated process water after stripping ammonia showed even better performance with a methane yield of 0.43 m3 kg(-1) VS. Recirculation of process water alone on the other hand, resulted in process inhibition at both TAN levels of 3.5 and 5.5 g-N l(-1). However, after a short period, the process recovered and adapted to the tested TAN levels. Thus, use of recirculated process water after stripping ammonia would not only evade potential inhibition due to ammonia but could avoid the use of fresh water for dilution of high solids protein-rich SS-OFMSW.

  11. Influence of aeration-homogenization system in stirred tank bioreactors, dissolved oxygen concentration and pH control mode on BHK-21 cell growth and metabolism.

    PubMed

    Núñez, Eutimio Gustavo Fernández; Leme, Jaci; de Almeida Parizotto, Letícia; Chagas, Wagner Antonio; de Rezende, Alexandre Gonçalves; da Costa, Bruno Labate Vale; Monteiro, Daniela Cristina Ventini; Boldorini, Vera Lucia Lopes; Jorge, Soraia Attie Calil; Astray, Renato Mancini; Pereira, Carlos Augusto; Caricati, Celso Pereira; Tonso, Aldo

    2014-08-01

    This work focused on determining the effect of dissolved oxygen concentration (DO) on growth and metabolism of BHK-21 cell line (host cell for recombinant proteins manufacturing and viral vaccines) cultured in two stirred tank bioreactors with different aeration-homogenization systems, as well as pH control mode. BHK-21 cell line adapted to single-cell suspension was cultured in Celligen without aeration cage (rotating gas-sparger) and Bioflo 110, at 10, 30 and 50 % air saturation (impeller for gas dispersion from sparger-ring). The pH was controlled at 7.2 as far as it was possible with gas mixtures. In other runs, at 30 and 50 % (DO) in Bioflo 110, the cells grew at pH controlled with CO2 and NaHCO3 solution. Glucose, lactate, glutamine, and ammonium were quantified by enzymatic methods. Cell concentration, size and specific oxygen consumption were also determined. When NaHCO3 solution was not used, the optimal DOs were 10 and 50 % air saturation for Celligen and Bioflo 110, respectively. In this condition maximum cell concentrations were higher than 4 × 10(6) cell/mL. An increase in maximum cell concentration of 36 % was observed in batch carried out at 30 % air saturation in a classical stirred tank bioreactor (Bioflo 110) with base solution addition. The optimal parameters defined in this work allow for bioprocess developing of viral vaccines, transient protein expression and viral vector for gene therapy based on BHK-21 cell line in two stirred tank bioreactors with different agitation-aeration systems.

  12. 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.

  13. 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. PMID:27168373

  14. Evaluation of parallel milliliter-scale stirred-tank bioreactors for the study of biphasic whole-cell biocatalysis with ionic liquids.

    PubMed

    Dennewald, Danielle; Hortsch, Ralf; Weuster-Botz, Dirk

    2012-01-01

    As clear structure-activity relationships are still rare for ionic liquids, preliminary experiments are necessary for the process development of biphasic whole-cell processes involving these solvents. To reduce the time investment and the material costs, the process development of such biphasic reaction systems would profit from a small-scale high-throughput platform. Exemplarily, the reduction of 2-octanone to (R)-2-octanol by a recombinant Escherichia coli in a biphasic ionic liquid/water system was studied in a miniaturized stirred-tank bioreactor system allowing the parallel operation of up to 48 reactors at the mL-scale. The results were compared to those obtained in a 20-fold larger stirred-tank reactor. The maximum local energy dissipation was evaluated at the larger scale and compared to the data available for the small-scale reactors, to verify if similar mass transfer could be obtained at both scales. Thereafter, the reaction kinetics and final conversions reached in different reactions setups were analysed. The results were in good agreement between both scales for varying ionic liquids and for ionic liquid volume fractions up to 40%. The parallel bioreactor system can thus be used for the process development of the majority of biphasic reaction systems involving ionic liquids, reducing the time and resource investment during the process development of this type of applications.

  15. Comparative reaction engineering studies for succinic acid production from sucrose by metabolically engineered Escherichia coli in fed-batch-operated stirred tank bioreactors.

    PubMed

    Hoefel, Torben; Faust, Georg; Reinecke, Liv; Rudinger, Nicolas; Weuster-Botz, Dirk

    2012-10-01

    This study presents a comparative reaction engineering analysis of metabolically engineered sucrose-utilizing Escherichia coli derived from E. coli K12 MG1655 for the anaerobic production of succinic acid. Production capacities of 16 different recombinant strains were evaluated in 48 parallel fed-batch-operated milliliter-scale stirred tank bioreactors (10 mL) with continuous CO₂ sparging. The effects of recombinant sucrose-utilization systems (csc-operon or scr-operon), enhancements of anaplerotic reactions (pck, ppc, maeA, maeB or heterologous pyc) and gene deletions (ldhA, adhE, ack-pta and ptsG) were studied with respect to the overall process performances of the respective recombinant strains. Both sucrose-utilization systems enabled the production of succinic acid from sucrose in E. coli K12 MG1655. Maximum succinate production was observed by overexpressing the pyruvate carboxylase from Corynebacterium glutamicum resulting in a succinate concentration of 26.8 g L⁻¹ after 48 h and a cell-specific productivity of 0.14 g g⁻¹ h⁻¹. Further experiments in a fed-batch-operated laboratory-scale stirred tank bioreactor (2 L) showed that micro-aerobic conditions preceding the anaerobic phase enhance succinic acid production of E. coli K12 MG1655-derived strains. The work demonstrates the importance of parallel approaches within the scope of applied metabolic engineering studies.

  16. 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.

  17. Oscillations in the reduction of permanganate by hydrogen peroxide or by ninhydrin in a batch reactor and mixed-mode oscillations in a continuous-flow stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Tóthová, Mária; Nagy, Arpád; Treindl, Ľudovít.

    1999-01-01

    The periodical reduction of permanganate by hydrogen peroxide or by ninhydrin with transient oscillations in a closed system has been observed and discussed in relation to the first two permanganate oscillators described earlier. The mixed-mode oscillations of the permanganate-H 2O 2 oscillating system in a continuous-flow stirred tank reactor have been described.

  18. 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.

  19. 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.

  20. 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

  1. Evaluation of the Small-Tank Tetraphenylborate Process Using a Bench-Scale, 20-L Continuous Stirred Tank Reactor System at Oak Ridge National Laboratory: Results of Test 5

    SciTech Connect

    Lee, D.D.

    2001-08-30

    The goal of the Savannah River Salt Waste Processing Program (SPP) is to evaluate the presently available technologies and select the most effective approach for treatment of high-level waste salt solutions currently stored in underground tanks at the U.S. Department of Energy's Savannah River Site in Aiken, South Carolina. One of the three technologies currently being developed for this application is the Small-Tank Tetraphenylborate Process (STTP). This process uses sodium tetraphenylborate (TPB) to precipitate and remove radioactive cesium from the waste and monosodium titanate (MST) to sorb and remove radioactive strontium and actinides. Oak Ridge National Laboratory is demonstrating this process at the 1:4000 scale using a 20-L-capacity continuous-flow stirred-tank reactor (CSTR) system. Since March 1999, five operating campaigns of the 20-L CSTR have been conducted. The ultimate goal is to verify that this process, under certain extremes of operating conditions, can meet the minimum treatment criteria necessary for processing and disposing of the salt waste at the Savannah River Saltstone Facility. The waste acceptance criteria (WAC) for {sup 137}Cs, {sup 90}Sr, and total alpha nuclides are <40 nCi/g, <40 nCi/g, and <18 nCi/g, respectively. However, to allow for changes in process conditions, the SPP is seeking a level of treatment that is about 50% of the WAC. The bounding separation goals for {sup 137}Cs and {sup 90}Sr are to obtain decontamination factors (DFs) of 40,000 (99.998% removal) and 26 (96.15% removal), respectively. (DF is mathematically defined as the concentration of contaminant in the waste feed divided by the concentration of contaminant in the effluent stream.)

  2. Performance comparison of a continuous-flow stirred-tank reactor and an anaerobic sequencing batch reactor for fermentative hydrogen production depending on substrate concentration.

    PubMed

    Kim, S-H; Han, S-K; Shin, H-S

    2005-01-01

    This study was conducted to compare the performance of a continuous-flow stirred-tank reactor (CSTR) and an anaerobic sequencing batch reactor (ASBR) for fermentative hydrogen production at various substrate concentrations. Heat-treated anaerobic sludge was utilized as an inoculum, and hydraulic retention time (HRT) for each reactor was maintained at 12 h. At the influent sucrose concentration of 5 g COD/L, start-up was not successful in both reactors. The CSTR, which was started-up at 10 g COD/L, showed stable hydrogen production at the influent sucrose concentrations of 10-60 g COD/L during 203 days. Hydrogen production was dependent on substrate concentration, resulting in the highest performance at 30 g COD/L. At the lower substrate concentration, the hydrogen yield (based on hexose consumed) decreased with biomass reduction and changes in fermentation products. At the higher substrate concentration, substrate inhibition on biomass growth caused the decrease of carbohydrate degradation and hydrogen yield (based on hexose added). The ASBR showed higher biomass concentration and carbohydrate degradation efficiency than the CSTR, but hydrogen production in the ASBR was less effective than that in the CSTR at all the substrate concentrations.

  3. Comparison of bioleaching of heavy metals from municipal sludge using indigenous sulfur and iron-oxidizing microorganisms: continuous stirred tank reactor studies.

    PubMed

    Pathak, Ashish; Kothari, Richa; Dastidar, M G; Sreekrishnan, T R; Kim, Dong J

    2014-01-01

    A comparative study was undertaken using indigenous sulfur-oxidizing microorganisms and iron-oxidizing microorganisms in separate 12 litre continuous stirred tank reactors (CSTRs) for solubilization of heavy metals from anaerobically digested sewage sludge. The CSTRs were operated at hydraulic retention times (HRTs) ranging from 4 to 10 days using sewage sludge feed having near neutral pH. The pH, oxidation-reduction potential (ORP) and solubilization efficiency of metals were found to be highly dependent on HRT and an increase in HRT led to higher solubilization of metals in both the CSTRs. In both the CSTRs, the CSTR operated with sulfur-oxidizing microorganisms at an HRT of 8 days was found to be optimum in solubilizing 58% Cu, 52% Ni, 72% Zn and 43% Cu from the sludge. The nutrient value, nitrogen and phosphorus of bioleached sludge was also conserved (<20% loss) at 8 days HRT. The metals fractionation study conducted using BCR sequential extraction procedure suggested that most of the metals remaining in the bioleached sludge were in the more stable fractions (F3 and F4) and, therefore, can be safely apply as a fertilizer on land.

  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. 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.

  6. On the effect of added impurity on crystal purity of urea in an oscillatory baffled crystallizer and a stirred tank crystallizer

    NASA Astrophysics Data System (ADS)

    McLachlan, Hannah; Ni, Xiong-Wei

    2016-05-01

    Previous work has indicated that crystals produced in oscillatory baffled crystallisers (OBC) from a relatively 'pure' starting environment gave statistically higher purities than that in stirred tank crystallisers (STC) under comparable conditions. In this work, a known amount of biuret (the impurity) was added to the 'pure' urea system and the results show that the OBC still produced higher purity crystals than the STC, although these purity values were statistically lower than from the 'pure' environment in both vessels. By evaluating crystallisation rates of both urea and biuret, we noticed that these rates are higher in the STC than in the OBC, which would have led to small crystals in the former vessel. The CSD data however gave the opposite result where the CSD is wider with more, large crystals in the STC than in the OBC, in particular in the presence of added impurity. These larger crystals are likely formed due to agglomeration coupled with incorporation of impurity, which leads to a lower purity.

  7. 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. PMID:27033608

  8. 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.

  9. 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%. PMID:22487130

  10. Bistability in isothermal photochemical systems: The A ⇆ h nu B --> h nu C reaction in a continuous flow stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Laplante, J. P.; Lavabre, D.; Micheau, J. C.

    1988-08-01

    In this paper we present a kinetic analysis of the consecutive photoreaction scheme A⇄hνB→hνC assuming the reaction is carried out in a continuous flow stirred tank reactor (CSTR). The reactor is kept at constant temperature and fed with reactant A at a constant flow rate. A numerical analysis of the model's stationary states reveals a range of constraints for which the system possesses multiple steady states. The observed bistability depends strongly on the rate constant of the B→A reaction k2 . It is typically observed when k2 is much larger than the other rate constants. Our numerical calculations also reveal a marked dependency on parameters such as the molar absorptivities and the irradiation intensity I0 . Interestingly, multiple steady states are only observed for intermediate values of I0 . Analytical approximations are obtained for the stationary states in the limit where the end-product C does not absorb light. These approximations are used to clarify the mechanism responsible for the light-induced instability.

  11. 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.

  12. 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.

  13. 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.

  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. 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. PMID:26513317

  16. 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.

    PubMed

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

    2002-09-01

    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.

  17. 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.

  18. The effect of heavy metals on microbial community structure of a sulfidogenic consortium in anaerobic semi-continuous stirred tank reactors.

    PubMed

    Kieu, Hoa T Q; Horn, Harald; Müller, Elisabeth

    2014-03-01

    The effect of heavy metals on community structure of a heavy metal tolerant sulfidogenic consortium was evaluated by using a combination of denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene and dissimilatory sulfite reductase (dsrB) gene fragments, 16S rRNA gene cloning analysis and fluorescence in situ hybridization (FISH). For this purpose, four anaerobic semi-continuous stirred tank reactors (referred as R1-R4) were run in parallel for 12 weeks at heavy metal loading rates of 1.5, 3, 4.5 and 7.5 mg l(-1) d(-1) each of Cu(2+), Ni(2+), Zn(2+), and Cr(6+), respectively. The abundance ratio of Desulfovibrio vulgaris detected by FISH to total cell counts was consistent with the obtained results of cloning and DGGE. This indicated that D. vulgaris was dominant in all analyzed samples and played a key role in heavy metal removal in R1, R2, and R3. In contrast, after 4 weeks of operation of R4, a distinct biomass loss was observed and no positive hybridized cells were detected by specific probes for the domain Bacteria, sulfate-reducing bacteria and D. vulgris. High removal efficiencies of heavy metals were achieved in R1, R2 and R3 after 12 weeks, whereas the precipitation of heavy metals in R4 was significantly decreased after 4 weeks and almost not observed after 6 weeks of operation. In addition, the anaerobic bacteria, such as Pertrimonas sulfuriphila, Clostridium sp., Citrobacter amalonaticus, and Klebsiella sp., identified from DGGE bands and clone library were hypothesized as heavy metal resistant bacteria at a loading rate of 1.5 mg l(-1) d(-1) of Cu(2+), Ni(2+), Zn(2+), and Cr(6+.)

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Complete genome sequence of Peptoniphilus sp. strain ING2-D1G isolated from a mesophilic lab-scale completely stirred tank reactor utilizing maize silage in co-digestion with pig and cattle manure for biomethanation.

    PubMed

    Tomazetto, Geizecler; Hahnke, Sarah; Maus, Irena; Wibberg, Daniel; Pühler, Alfred; Schlüter, Andreas; Klocke, Michael

    2014-12-20

    The bacterium Peptoniphilus sp. strain ING2-D1G (DSM 28672), a mesophilic and obligate anaerobic bacterium belonging to the order Clostridiales was isolated from a biogas-producing lab-scale completely stirred tank reactor (CSTR) optimized for anaerobic digestion of maize silage in co-fermentation with pig and cattle manure. In this study, the whole genome sequence of Peptoniphilus sp. strain ING2-D1G, a new isolate potentially involved in protein breakdown and acidogenesis during biomass degradation, is reported. The chromosome of this strain is 1.6Mb in size and encodes genes predicted to be involved in the production of acetate, lactate and butyrate specifying the acidogenic metabolism of the isolate.

  5. 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.

  6. 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. PMID:23828243

  7. Aperiodicity resulting from two-cycle coupling in the Belousov-Zhabotinskii reaction. III. Analysis of a model of the effect of spatial inhomogeneities at the input ports of a continuous-flow, stirred tank reactor

    NASA Astrophysics Data System (ADS)

    Györgyi, László; Field, Richard J.

    1989-11-01

    Deterministic chaos is a well-established phenomenon in continuous-flow, stirred tank reactor (CSTR) experiments with the oscillatory Belousov-Zhabotinskii (BZ) reaction. However, it has not yet been possible to reproduce the experimentally observed, robust chaos in simulations using realistic models of the homogeneous chemical kinetics of the BZ reaction. That it may be necessary to consider spatial inhomogeneities in modeling the BZ chaos is suggested by the existence of strong stirring effects on the aperiodic behavior and by the difficulty of reproducing chaos under the same conditions in reactors of different physical configuration. Such inhomogeneity might result from a lack of perfect mixing in the CSTR, especially near the inlets, or from diffusion of species at low flow rates from the CSTR reaction mixture into the tips of the inlets. The presence of spatial inhomogeneities allows coupling between essentially independent oscillators, a well-known source of chaos. Such a model using a realistic representation of the BZ kinetics leads to an eight-variable set of ordinary differential equations. Numerical analysis of these equations by continuation methods and by numerical integration shows the existence of broad regions of chaos and various hysteresis effects involving limit cycles, a steady state and/or a strange attractor. Tristability was found in calculations in a narrow flow rate range. The computed behavior appears for parameter values closely related to the values used experimentally to obtain similar phenomena, and the visual similarity of the computed and experimental strange attractors is striking. The experimental routes to chaos, period doubling, intermittency, and secondary Hopf bifurcations are all reproduced in the simulations. The computed and experimental structures of periodic windows observed within chaotic regions also are very similar.

  8. 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

  9. 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.

  10. 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. PMID:25911592

  11. 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.

  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. 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.

  14. 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.

  15. 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. PMID:24576559

  16. 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.

  17. Effects of dissolved oxygen and agitation on production of serratiopeptidase by Serratia marcescens NRRL B-23112 in stirred tank bioreactor and its kinetic modeling.

    PubMed

    Pansuriya, Ruchir; Singhal, Rekha

    2011-04-01

    The effects of the agitation and aeration rates on the production of serratiopeptidase (SRP) in a 5-L fermentor (working volume 2-l) were systematically investigated using Serratia marcescens NRRL B-23112. The dissolved oxygen concentration, pH, biomass, SRP yield, and maltose utilization were all continuously measured during the course of the fermentation runs. The efficiencies of the aeration and agitation were evaluated based on the volumetric mass transfer coefficient (K(L)a). The maximum SRP production of 11,580 EU/ml with a specific SRP productivity of 78.8 EU/g/h was obtained with an agitation of 400 rpm and aeration of 0.075 vvm, which was 58% higher than the shake-flask level. The KLa for the fermentation system supporting the maximum production (400 rpm, 0.075 vvm) was 11.3 h(-1). Under these fermentor optimized conditions, kinetic modeling was performed to understand the detailed course of the fermentation process. The resulting logistic and Luedeking-Piret models provided an effective description of the SRP fermentation, where the correlation coefficients for cell growth, SRP formation, and substrate consumption were 0.99, 0.94, and 0.84, respectively, revealing a good agreement between the model-predicted and experimental results. The kinetic analysis of the batch fermentation process for the production of SRP demonstrated the SRP production to be mixed growth associated.

  18. F-5-L Boat Seaplane : performance characteristics

    NASA Technical Reports Server (NTRS)

    Diehl, W S

    1922-01-01

    Performance characteristics for the F-5-L Boat Seaplane are given. Characteristic curves for the RAF-6 airfoil and the F-5-L wings, parasite resistance and velocity data, engine and propeller characteristics, effective and maximum horsepower, and cruising performance are discussed.

  19. Effects of shock 2,4-dichlorophenol (DCP) and cod loading rates on the removal of 2,4-DCP in a sequential upflow anaerobic sludge blanket/aerobic completely stirred tank reactor system.

    PubMed

    Uluköy, A; Sponza, D T

    2008-04-01

    The treatability of 2,4-dwichlorophenol (DCP) was studied in an anaerobic/aerobic sequential reactor system. Laboratory scale upflow anaerobic sludge blanket (UASB) reactor/completely stirred tank reactors (CSTR) were operated at constant 2,4-DCP concentrations, and increasing chemical oxygen demand (COD) loading rates. The effect of shock organic loading rates on 2,4-DCP, COD removal efficiencies and methane gas production were investigated in the UASB reactor. When the organic loading rate was increased from 3.6 g l(-1) d(-1) to 30.16 g l(-1) d(-1), the COD and 2,4-DCP removal efficiencies decreased from 80 to 25% and from 99 to 60% in the UASB reactor. The optimum organic loading rates for maximum 2,4-DCP (E=99-100%) and COD (E=65-85%) removal efficiencies were 25-30 and 8-20 g-COD l(-1) d(-1), respectively. The percentage of methane of the total gas varied between 70 and 80 while the organic loadings were 18 g-COD l(-1) d(-1) and 20.36 g-COD l(-1) d(-1), respectively. During 80 days of operation, 2,4-DCP concentration was found to be below 0.5 and 0.1 mg l(-1) in aerobic reactor effluent resulting in 78 and 100% removal efficiencies. When the hydraulic retention time (HRT) was 18.72 h, the 2,4-DCP removal efficiency was 97% in the aerobic reactor. The optimum COD removal efficiency was 78.83% in anaerobic reactor effluent at an influent COD loading rate of 7.238 g-COD l(-1) d(-1) while 83.6% maximum COD removal efficiency was obtained in the aerobic reactor, resulting in a total COD removal efficiency of 96.83% in the whole system. The 2,4-DCP removal efficiency was 99% in the sequential anaerobic (UASB)/aerobic (CSTR) reactor system at COD loading rates varying between 11.46 and 30.16 g-COD l(-1) d(-1).

  20. 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.

  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. 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.

  3. 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.

  4. Stirring rate regulates the proliferation and metabolism of microencapsulated recombinant CHO cells.

    PubMed

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

    2015-01-01

    Stirred tank bioreactors are the most widely used method for the large-scale culture of mammalian cells. However, the scale of stirred tank bioreactors is limited by insufficient oxygen/nutrient mixing and the accumulation of waste products in high cell density cultures. The most effective method to solve these problems is to increase the stirring rate; this usually leads to increased cell proliferation, but can decrease the utilization of nutrients for recombinant protein synthesis. To investigate the effects of stirring rate on the proliferation, metabolism, and recombinant protein yield of microencapsulated recombinant Chinese hamster ovary (rCHO) cells, the cells were cultured under different stirring rates, and cell viability, metabolic activity, and protein yield were measured. Microencapsulation promoted Desmodus rotundus salivary plasminogen activator expression, and higher stirring rates promoted increases in microencapsulated cell density and metabolic activity. However, the maximum yield of recombinant protein was obtained at a moderate stirring rate, whereas protein yield was decreased at the highest tested stirring rate. The stirring rate had a significant impact on the growth and protein expression of microencapsulated rCHO cells, and a specific stirring rate was identified to maximize the yield of recombinant protein. PMID:25524589

  5. 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.

  6. 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.

  7. Multiple test tubes stirred mechanically

    NASA Technical Reports Server (NTRS)

    Leon, H. J.; Strong, I. J.

    1965-01-01

    Mechanical device simultaneously stirs multiple test tubes under controlled laboratory conditions. The invention provides a variable stirring rate, minimal amount of contamination of tube contents, unattended and simple operation, and easy maintenance and cleaning.

  8. 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.

  9. 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.

  10. 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.

  11. 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. PMID:23860724

  12. 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.

  13. 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.

  14. 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.

  15. DIALYSIS WITH STIRRING.

    PubMed

    Kunitz, M; Simms, H S

    1928-05-20

    Substances to be purified by dialysis are placed in collodion bags together with a toy "marble" or a bubble of air. The bags are stoppered and placed in glass tubes of a rocking machine. Distilled water of the desired temperature is circulated through the tubes (around the bags) at a rate of about 8 cc. per minute per bag while the machine is in motion. The rolling of the marbles or bubbles causes stirring which makes it possible to remove the salts from a protein solution in 24 to 48 hours.

  16. Stirring turbulence with turbulence

    NASA Astrophysics Data System (ADS)

    Cekli, Hakki Ergun; Joosten, René; van de Water, Willem

    2015-12-01

    We stir wind-tunnel turbulence with an active grid that consists of rods with attached vanes. The time-varying angle of these rods is controlled by random numbers. We study the response of turbulence on the statistical properties of these random numbers. The random numbers are generated by the Gledzer-Ohkitani-Yamada shell model, which is a simple dynamical model of turbulence that produces a velocity field displaying inertial-range scaling behavior. The range of scales can be adjusted by selection of shells. We find that the largest energy input and the smallest anisotropy are reached when the time scale of the random numbers matches that of the largest eddies of the wind-tunnel turbulence. A large mismatch of these times creates a highly intermittent random flow with interesting but quite anomalous statistics.

  17. Stirring turbulence with turbulence

    NASA Astrophysics Data System (ADS)

    van de Water, Willem; Ergun Cekli, Hakki; Joosten, Rene

    2011-11-01

    We stir wind-tunnel turbulence with an active grid that consists of rods with attached vanes. The time-varying angle of these rods is controlled by random numbers. We study the response of turbulence on the statistical properties of these random numbers. The random numbers are generated by the Gledzer-Ohkitani-Yamada shell model, which is a simple dynamical model of turbulence that produces a velocity field displaying inertial-range scaling behavior. The range of scales can be adjusted by selection of shells. We find that the largest energy input and the smallest anisotropy are reached when the time scale of the random numbers matches that of the large eddies in the wind-tunnel turbulence. A large mismatch of these times creates a flow with interesting statistics, but it is not turbulence.

  18. 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.

  19. Vitrification of Cesium-Laden Organic Ion Exchange Resin in a Stirred Melter

    SciTech Connect

    Cicero-Herman, C.A; Sargent, T.N.; Overcamp, T.J.; Bickford, D.F.

    1997-07-09

    The goal of this research was a feasibility study for vitrifying the organic ion exchange resin in a stirred-tank melter. Tests were conducted to determine the fate of cesium including the feed, exit glass, and offgas streams and to assess any impact of feeding the resin on the melter or its performance.

  20. Stirring effects and bistability in the iodate-arsenous acid reaction: Premixed vs segregated flows

    NASA Astrophysics Data System (ADS)

    Hannon, L.; Horsthemke, W.

    1987-01-01

    Using a coalescence-dispersion model of the continuous flow-stirred tank reactor (CSTR), we study the effect of premixed vs nonpremixed reactant flows on chemical bistability. The region of bistability is smaller for segregated feed streams than for a fully premixed feed stream. The transition from flow branch to thermodynamic branch is particularly sensitive to the feed stream configuration.

  1. The 5L Instructional Design For Exploring Legacies through Biography

    ERIC Educational Resources Information Center

    Boulware, Beverly J.; Monroe, Eula E.; Wilcox, Bradley Ray

    2013-01-01

    People who have impacted generations have left legacies we can explore today through biographies. The 5L instructional design introduced in this article includes five components: Listen, Learn, Locate, Link, and Legacy. In the "Listen" section, teachers use storytelling and read-alouds to introduce individuals who shaped history. During…

  2. kLa of stirred tank bioreactors revisited.

    PubMed

    Schaepe, S; Kuprijanov, A; Sieblist, C; Jenzsch, M; Simutis, R; Lübbert, A

    2013-12-01

    By means of improved feedback control kLa measurements become possible at a precision and reproducibility that now allow a closer look at the influences of power input and aeration rate on the oxygen mass transfer. These measurements are performed online during running fermentations without a notable impact on the biochemical conversion processes. A closer inspection of the mass transfer during cultivations showed that at least the number of impellers influences mass transfer and mixing: On the laboratory scale, two hollow blade impellers clearly showed a larger kLa than the usually employed three impeller versions when operated at the same agitation power and aeration rate. Hollow blade impellers are preferable under most operational conditions because of their perfect gas handling capacity. Mixing time studies showed that these two impeller systems are also preferable with respect to mixing. Furthermore the widths of the baffle bars depict a significant influence on the kLa. All this clearly supports the fact that it is not only the integral power density that finally determines kLa.

  3. 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.

  4. 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.

  5. kLa of stirred tank bioreactors revisited.

    PubMed

    Schaepe, S; Kuprijanov, A; Sieblist, C; Jenzsch, M; Simutis, R; Lübbert, A

    2013-12-01

    By means of improved feedback control kLa measurements become possible at a precision and reproducibility that now allow a closer look at the influences of power input and aeration rate on the oxygen mass transfer. These measurements are performed online during running fermentations without a notable impact on the biochemical conversion processes. A closer inspection of the mass transfer during cultivations showed that at least the number of impellers influences mass transfer and mixing: On the laboratory scale, two hollow blade impellers clearly showed a larger kLa than the usually employed three impeller versions when operated at the same agitation power and aeration rate. Hollow blade impellers are preferable under most operational conditions because of their perfect gas handling capacity. Mixing time studies showed that these two impeller systems are also preferable with respect to mixing. Furthermore the widths of the baffle bars depict a significant influence on the kLa. All this clearly supports the fact that it is not only the integral power density that finally determines kLa. PMID:24021302

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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)

  13. Protein crystallization in stirred systems--scale-up via the maximum local energy dissipation.

    PubMed

    Smejkal, Benjamin; Helk, Bernhard; Rondeau, Jean-Michel; Anton, Sabine; Wilke, Angelika; Scheyerer, Peter; Fries, Jacqueline; Hekmat, Dariusch; Weuster-Botz, Dirk

    2013-07-01

    Macromolecular bioproducts like therapeutic proteins have usually been crystallized with µL-scale vapor diffusion experiments for structure determination by X-ray diffraction. Little systematic know-how exists for technical-scale protein crystallization in stirred vessels. In this study, the Fab-fragment of the therapeutic antibody Canakinumab was successfully crystallized in a stirred-tank reactor on a 6 mL-scale. A four times faster onset of crystallization of the Fab-fragment was observed compared to the non-agitated 10 µL-scale. Further studies on a liter-scale with lysozyme confirmed this effect. A 10 times faster onset of crystallization was observed in this case at an optimum stirrer speed. Commonly suggested scale-up criteria (i.e., minimum stirrer speed to keep the protein crystals in suspension or constant impeller tip speed) were shown not to be successful. Therefore, the criterion of constant maximum local energy dissipation was applied for scale-up of the stirred crystallization process for the first time. The maximum local energy dissipation was estimated by measuring the drop size distribution of an oil/surfactant/water emulsion in stirred-tank reactors on a 6 mL-, 100 mL-, and 1 L-scale. A comparable crystallization behavior was achieved in all stirred-tank reactors when the maximum local energy dissipation was kept constant for scale-up. A maximum local energy dissipation of 2.2 W kg(-1) was identified to be the optimum for lysozyme crystallization at all scales under study.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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. PMID:26992498

  1. 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.

  2. 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.

  3. 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.

  4. 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…

  5. 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

  6. Scalable ex vivo expansion of human mesenchymal stem/stromal cells in microcarrier-based stirred culture systems.

    PubMed

    Carmelo, Joana G; Fernandes-Platzgummer, Ana; Cabral, Joaquim M S; da Silva, Cláudia Lobato

    2015-01-01

    The clinical demand for human mesenchymal stem/stromal cells (MSC) drives the need for reproducible, cost-effective, and good manufacturing practices (GMP)-compliant ex vivo expansion protocols. Bioprocess engineering strategies, namely controlled stirred bioreactor systems combined with the use of xenogeneic(xeno)-free materials, provide proper tools to develop and optimize cell manufacturing for the rapid expansion of human MSC for cellular therapies. Herein we describe a microcarrier-based stirred culture system operating under xeno-free conditions using a controlled stirred-tank bioreactor for an efficient and controlled ex vivo expansion of human MSC. This culture platform can be applied to MSC from different human sources, as well as different microcarriers and xeno-free medium formulations.

  7. Scalable ex vivo expansion of human mesenchymal stem/stromal cells in microcarrier-based stirred culture systems.

    PubMed

    Carmelo, Joana G; Fernandes-Platzgummer, Ana; Cabral, Joaquim M S; da Silva, Cláudia Lobato

    2015-01-01

    The clinical demand for human mesenchymal stem/stromal cells (MSC) drives the need for reproducible, cost-effective, and good manufacturing practices (GMP)-compliant ex vivo expansion protocols. Bioprocess engineering strategies, namely controlled stirred bioreactor systems combined with the use of xenogeneic(xeno)-free materials, provide proper tools to develop and optimize cell manufacturing for the rapid expansion of human MSC for cellular therapies. Herein we describe a microcarrier-based stirred culture system operating under xeno-free conditions using a controlled stirred-tank bioreactor for an efficient and controlled ex vivo expansion of human MSC. This culture platform can be applied to MSC from different human sources, as well as different microcarriers and xeno-free medium formulations. PMID:25063496

  8. Tank 241-S-111: Tank characterization plan

    SciTech Connect

    Homi, C.S.

    1995-03-07

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, ORNL, and PNL tank vapor program. Scope of this plan is to provide guidance for sampling and analysis of vapor samples from tank 241-S-111 (this tank is on the organic and flammable gas watch list). This tank received Redox plant waste, among other wastes.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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.

  20. 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.

  1. Structural basis for acyl-group discrimination by human Gcn5L2

    PubMed Central

    Ringel, Alison E.; Wolberger, Cynthia

    2016-01-01

    Gcn5 is a conserved acetyltransferase that regulates transcription by acetylating the N-terminal tails of histones. Motivated by recent studies identifying a chemically diverse array of lysine acyl modifications in vivo, the acyl-chain specificity of the acetyltransferase human Gcn5 (Gcn5L2) was examined. Whereas Gcn5L2 robustly catalyzes lysine acetylation, the acyltransferase activity of Gcn5L2 becomes progressively weaker with increasing acyl-chain length. To understand how Gcn5 discriminates between different acyl-CoA molecules, structures of the catalytic domain of human Gcn5L2 bound to propionyl-CoA and butyryl-CoA were determined. Although the active site of Gcn5L2 can accommodate propionyl-CoA and butyryl-CoA without major structural rearrangements, butyryl-CoA adopts a conformation incompatible with catalysis that obstructs the path of the incoming lysine residue and acts as a competitive inhibitor of Gcn5L2 versus acetyl-CoA. These structures demonstrate how Gcn5L2 discriminates between acyl-chain donors and explain why Gcn5L2 has weak activity for acyl moieties that are larger than an acetyl group. PMID:27377381

  2. 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.

  3. Tank 241-BX-106: Tank characterization plan

    SciTech Connect

    Schreiber, R.D.

    1995-03-06

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, and WHC 222-S Laboratory. Scope of this plan is to provide guidance for sampling and analysis of samples for tank 241-BX-106. (Waste from this tank shall be transferred to a double-shell tank.)

  4. The effect of stirring in the hydrothermal process to convert the mixed municipal solid waste into uniform solid fuel

    NASA Astrophysics Data System (ADS)

    Prawisudha, P.; Mu'min, G. F.; Yoshikawa, K.; Pasek, A. D.

    2016-06-01

    An innovative waste treatment technology has been developed in Indonesia to treat the mixed municipal solid waste into a solid fuel by employing the hydrothermal process. A mixture of organic and plastic waste was treated in a 2.5 L reactor using saturated steam in the temperature range of 120 to 180 °C. Two modes of operation were employed to achieve two different goals, i.e. without stirring (NS mode) and with stirring (WS mode). It was observed that both modes resulted in increasing density of product up to twofold of the raw MSW. In NS mode, the processed mixed MSW was converted into two different products; however, in WS mode the bulky plastic was converted into small granules, producing a uniform product. The results suggest that by hydrothermal treatment, the organic fibers in the organic parts are trapped into the plastic, and the stirring breaks the bulky plastics, producing uniform granules suitable as solid fuel. Therefore, the stirring during the hydrothermal process can be a solution to treat the MSW as it is, without any separation, to produce a clean and renewable energy source.

  5. 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…

  6. Stirring the Ashes of Public Discourse.

    ERIC Educational Resources Information Center

    Marinara, Martha

    Sylvia Plath's confessional poem, "Lady Lazarus" can be used to illustrate a connection between autobiography and social critique. "You poke and stir" among the institutions that form social relations--the educational system, the court system, the economic system--to find individuals whose lives, whose joys and pains, and struggles for survival…

  7. 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.

  8. C5L2: a controversial receptor of complement anaphylatoxin, C5a.

    PubMed

    Li, Rui; Coulthard, Liam G; Wu, M C L; Taylor, Stephen M; Woodruff, Trent M

    2013-03-01

    C5a is the paramount proinflammatory mediator of the complement cascade, and has been previously thought to act only through a single, G-protein-coupled, C5a receptor (C5aR; also termed CD88). In 2000, a second C5a receptor, C5L2 (previously known as GPR77), was discovered; yet, despite 12 yr of intensive research, its biological, or pathophysiological, function is both enigmatic and controversial. Unlike C5aR, this receptor does not couple to G proteins, and early studies promoted the hypothesis that C5L2 functions as a decoy receptor. However, recent data have provided other evidence for more complicated and conflicting interactions between C5L2 and other inflammatory mediators. C5L2 has been recently demonstrated to physically interact with both C5aR and β-arrestin to negatively regulate C5aR signaling toward an anti-inflammatory manner, and to reduce pathology, in several disease models in vivo. In direct contrast, other groups have demonstrated that C5L2 stimulation caused release of HMGB1 both in vitro and in vivo, and enhanced pathology in sepsis models, suggesting a clear proinflammatory signaling role. These astoundingly contradictory data challenge our precepts and complicate the foundational bases for the possible targeting of C5L2 as a therapeutic option in inflammatory disease. C5L2 may be the great masquerader in complement biology; its function dependent on the cell type, species, and disease context. Because of these unusual and unforeseen complexities, we present the current state of knowledge on C5L2 structure, expression and, most controversially, its putative functions.-Li, R., Coulthard, L.G., Wu, M. C. L., Taylor, S. M., Woodruff, T. M. C5L2: a controversial receptor of complement anaphylatoxin, C5a. PMID:23239822

  9. Stirred batch crystallization of a therapeutic antibody fragment.

    PubMed

    Hebel, Dirk; Huber, Sabine; Stanislawski, Bernd; Hekmat, Dariusch

    2013-07-20

    Technical-scale crystallization of therapeutic proteins may not only allow for a significant cost-reduction in downstream processing, but also enable new applications, e.g., the use of crystal suspensions for subcutaneous drug delivery. In this work, the crystallization of the antigen-binding fragment FabC225 was studied. First, vapor diffusion crystallization conditions from the literature were transferred to 10μL-scale microbatch experiments. A phase diagram was developed in order to identify the crystallization window. The conditions obtained from the microbatch experiments were subsequently transferred to parallelized 5mL-scale stirred-tank crystallizers. This scalable and reproducible agitated crystallization system allowed for an optimization of the crystallization process based on quantitative measurements. The optimized crystallization process resulted in an excellent yield of 99% in less than 2h by increasing the concentration of the crystallization agent ammonium sulfate during the process. The successful scalability of the Fab fragment crystallization process to 100mL-scale crystallizers based on geometric similarity was demonstrated. A favorable crystal size distribution was obtained. Furthermore, a wash step was introduced in order to remove unfavorable low-molecular substances from the crystals.

  10. 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.

  11. Scale-up of mouse embryonic stem cell expansion in stirred bioreactors.

    PubMed

    Fernandes-Platzgummer, Ana; Diogo, Maria M; Baptista, Ricardo P; da Silva, Cláudia Lobato; Cabral, Joaquim M S

    2011-01-01

    The aim of this study was to develop a robust, quality controlled and reproducible large-scale culture system using serum-free (SF) medium to obtain vast numbers of embryonic stem (ES) cells as a starting source for potential applications in tissue regeneration, as well as for drug screening studies. Mouse ES (mES) cells were firstly cultured on microcarriers in spinner flasks to investigate the effect of different parameters such as the agitation rate and the feeding regimen. Cells were successfully expanded at agitation rates up to 60 rpm using the SF medium and no significant differences in terms of growth kinetics or metabolic profiles were found between the two feeding regimens evaluated: 50% medium renewal every 24 h or 25% every 12 h. Overall, cells reached maximum concentrations of (4.2 ± 0.4) and (5.6 ± 0.8) ×10(6) cells/mL at Day 8 for cells fed once or twice per day; which corresponds to an increase in total cell number of 85 ± 7 and 108 ± 16, respectively. To have a more precise control over culture conditions and to yield a higher number of cells, the scale-up of the spinner flask culture system was successfully accomplished by using a fully controlled stirred tank bioreactor. In this case, the concentration of mES cells cultured on microcarriers increased 85 ± 15-fold over 11 days. Importantly, mES cells expanded under stirred conditions, in both spinner flask and fully controlled stirred tank bioreactor, using SF medium, retained the expression of pluripotency markers such as Oct-4, Nanog, and SSEA-1 and their differentiation potential into cells of the three embryonic germ layers.

  12. 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.

  13. Friction Stir Processing Technology: A Review

    NASA Astrophysics Data System (ADS)

    Ma, Z. Y.

    2008-03-01

    Friction stir processing (FSP), developed based on the basic principles of friction stir welding (FSW), a solid-state joining process originally developed for aluminum alloys, is an emerging metalworking technique that can provide localized modification and control of microstructures in near-surface layers of processed metallic components. The FSP causes intense plastic deformation, material mixing, and thermal exposure, resulting in significant microstructural refinement, densification, and homogeneity of the processed zone. The FSP technique has been successfully used for producing the fine-grained structure and surface composite, modifying the microstructure of materials, and synthesizing the composite and intermetallic compound in situ. In this review article, the current state of the understanding and development of FSP is addressed.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Homozygous mutation of STXBP5L explains an autosomal recessive infantile-onset neurodegenerative disorder.

    PubMed

    Kumar, Raman; Corbett, Mark A; Smith, Nicholas J C; Jolly, Lachlan A; Tan, Chuan; Keating, Damien J; Duffield, Michael D; Utsumi, Toshihiko; Moriya, Koko; Smith, Katherine R; Hoischen, Alexander; Abbott, Kim; Harbord, Michael G; Compton, Alison G; Woenig, Joshua A; Arts, Peer; Kwint, Michael; Wieskamp, Nienke; Gijsen, Sabine; Veltman, Joris A; Bahlo, Melanie; Gleeson, Joseph G; Haan, Eric; Gecz, Jozef

    2015-04-01

    We report siblings of consanguineous parents with an infantile-onset neurodegenerative disorder manifesting a predominant sensorimotor axonal neuropathy, optic atrophy and cognitive deficit. We used homozygosity mapping to identify an ∼12-Mbp interval identical by descent (IBD) between the affected individuals on chromosome 3q13.13-21.1 with an LOD score of 2.31. We combined family-based whole-exome and whole-genome sequencing of parents and affected siblings and, after filtering of likely non-pathogenic variants, identified a unique missense variant in syntaxin-binding protein 5-like (STXBP5L c.3127G>A, p.Val1043Ile [CCDS43137.1]) in the IBD interval. Considering other modes of inheritance, we also found compound heterozygous variants in FMNL3 (c.114G>C, p.Phe38Leu and c.1372T>G, p.Ile458Leu [CCDS44874.1]) located on chromosome 12. STXBP5L (or Tomosyn-2) is expressed in the central and peripheral nervous system and is known to inhibit neurotransmitter release through inhibition of the formation of the SNARE complexes between synaptic vesicles and the plasma membrane. FMNL3 is expressed more widely and is a formin family protein that is involved in the regulation of cell morphology and cytoskeletal organization. The STXBP5L p.Val1043Ile variant enhanced inhibition of exocytosis in comparison with wild-type (WT) STXBP5L. Furthermore, WT STXBP5L, but not variant STXBP5L, promoted axonal outgrowth in manipulated mouse primary hippocampal neurons. However, the FMNL3 p.Phe38Leu and p.Ile458Leu variants showed minimal effects in these cells. Collectively, our clinical, genetic and molecular data suggest that the IBD variant in STXBP5L is the likely cause of the disorder.

  19. Assemblies of Conformal Tanks

    NASA Technical Reports Server (NTRS)

    DeLay, Tom

    2009-01-01

    Assemblies of tanks having shapes that conform to each other and/or conform to other proximate objects have been investigated for use in storing fuels and oxidizers in small available spaces in upper stages of spacecraft. Such assemblies might also prove useful in aircraft, automobiles, boats, and other terrestrial vehicles in which space available for tanks is limited. The basic concept of using conformal tanks to maximize the utilization of limited space is not new in itself: for example, conformal tanks are used in some automobiles to store windshield -washer liquid and coolant that overflows from radiators. The novelty of the present development lies in the concept of an assembly of smaller conformal tanks, as distinguished from a single larger conformal tank. In an assembly of smaller tanks, it would be possible to store different liquids in different tanks. Even if the same liquid were stored in all the tanks, the assembly would offer an advantage by reducing the mechanical disturbance caused by sloshing of fuel in a single larger tank: indeed, the requirement to reduce sloshing is critical in some applications. The figure shows a prototype assembly of conformal tanks. Each tank was fabricated by (1) copper plating a wax tank mandrel to form a liner and (2) wrapping and curing layers of graphite/epoxy composite to form a shell supporting the liner. In this case, the conformal tank surfaces are flat ones where they come in contact with the adjacent tanks. A band of fibers around the outside binds the tanks together tightly in the assembly, which has a quasi-toroidal shape. For proper functioning, it would be necessary to maintain equal pressure in all the tanks.

  20. 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

  1. Tank 241-BX-104 tank characterization plan

    SciTech Connect

    Carpenter, B.C.

    1994-12-14

    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-BX-104.

  2. 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.

  3. 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.

  4. Mixing of dye in a model scald tank.

    PubMed

    Cason, J A; Shackelford, A D

    1999-10-01

    A model scald tank was constructed to study the mixing pattern of water in a poultry scalding system. Tank dimensions were approximately 6 m long by 10.5 cm wide with a water depth of 18 cm. Water was vigorously agitated with compressed air delivered through a 1.9-cm polyvinyl chloride pipe on the bottom of the tank. Food coloring was added to the tank at a single point, and water samples were taken at distances of 0, 0.5, 1.0, 1.5, and 2.5 m every 30 s for 10 min, with 0 or 10 L/min water flow through the tank. Dye concentration was determined spectrophotometrically. A chain drive was then installed above the tank with aluminum paddles (area about 25% of tank cross-sectional area) attached to the chain every 15.2 cm to simulate the movement of carcasses through the water at 140 carcasses per minute. Food coloring was added to the tank, and water samples were taken every 15 s for 2.5 min, with 0 or 13.5 L/min water flow through the tank. A computer program based on perfect mixing of water in small slices or cells within the tank was adjusted until predicted dye movement matched sampling data, with correlations of 0.91 or better at all sampling points. For scalder designs with uniform mixing of water, the computer model can predict mixing patterns, including counterflow conditions in a single tank, well enough to yield realistic residence time patterns for bacteria suspended in scald water. PMID:10536796

  5. 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.

  6. 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)

  7. 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...

  8. 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...

  9. 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..., Large Packaging, cargo tank, or multi-unit tank car tank) containing a hazardous material in...

  10. 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...

  11. Large scale validation of the M5L lung CAD on heterogeneous CT datasets

    SciTech Connect

    Lopez Torres, E. E-mail: cerello@to.infn.it; Fiorina, E.; Pennazio, F.; Peroni, C.; Saletta, M.; Cerello, P. E-mail: cerello@to.infn.it; Camarlinghi, N.; Fantacci, M. E.

    2015-04-15

    Purpose: M5L, a fully automated computer-aided detection (CAD) system for the detection and segmentation of lung nodules in thoracic computed tomography (CT), is presented and validated on several image datasets. Methods: M5L is the combination of two independent subsystems, based on the Channeler Ant Model as a segmentation tool [lung channeler ant model (lungCAM)] and on the voxel-based neural approach. The lungCAM was upgraded with a scan equalization module and a new procedure to recover the nodules connected to other lung structures; its classification module, which makes use of a feed-forward neural network, is based of a small number of features (13), so as to minimize the risk of lacking generalization, which could be possible given the large difference between the size of the training and testing datasets, which contain 94 and 1019 CTs, respectively. The lungCAM (standalone) and M5L (combined) performance was extensively tested on 1043 CT scans from three independent datasets, including a detailed analysis of the full Lung Image Database Consortium/Image Database Resource Initiative database, which is not yet found in literature. Results: The lungCAM and M5L performance is consistent across the databases, with a sensitivity of about 70% and 80%, respectively, at eight false positive findings per scan, despite the variable annotation criteria and acquisition and reconstruction conditions. A reduced sensitivity is found for subtle nodules and ground glass opacities (GGO) structures. A comparison with other CAD systems is also presented. Conclusions: The M5L performance on a large and heterogeneous dataset is stable and satisfactory, although the development of a dedicated module for GGOs detection could further improve it, as well as an iterative optimization of the training procedure. The main aim of the present study was accomplished: M5L results do not deteriorate when increasing the dataset size, making it a candidate for supporting radiologists on large

  12. 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.

  13. Automated multisyringe stir bar sorptive extraction using robust montmorillonite/epoxy-coated stir bars.

    PubMed

    Ghani, Milad; Saraji, Mohammad; Maya, Fernando; Cerdà, Víctor

    2016-05-01

    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.

  14. 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.

  15. 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.

  16. 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....

  17. Tank 241-BX-110 tank characterization report

    SciTech Connect

    Schreiber, R.D., Westinghouse Hanford

    1996-05-22

    This document summarizes the information on the historical uses, present status and the sampling and analysis results of waste stored in Tank 241-BX-110. This reports supports the requirements of Tri-Party Agreement Milestone M-44-09.

  18. Recent developments in stir bar sorptive extraction.

    PubMed

    He, Man; Chen, Beibei; Hu, Bin

    2014-03-01

    As a crucial step in qualitative and quantitative analysis, sample pretreatment is commonly used to isolate the target analytes, concentrate them, or convert them into the forms tailored to the instrumental analysis. In recent years, there has been a trend for sample pretreatment techniques to become more miniaturized and more environmentally friendly. Stir bar sorptive extraction (SBSE), which was developed in 1999, is such an environmentally friendly microextraction technique. Compared with other microextraction techniques, including solid phase microextraction and liquid phase microextraction, SBSE provides a higher extraction efficiency and better reproducibility owing to the much greater amount of the extraction phase, and no special skills are required. However, there are some problems associated with SBSE, such as the limited applicable coatings, coating abrasion of the laboratory-made stir bar, and the difficulty in automation, which restrict the further improvement and application of SBSE. This review focuses on the development of SBSE in the past decade, in terms of coating preparation, automated systems, novel extraction modes, its use with various instruments, and applications in food, environmental, and biological samples.

  19. 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.

  20. 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.

  1. Certification of a weld produced by friction stir welding

    SciTech Connect

    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.

  2. 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.

  3. 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.

  4. 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...

  5. 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

  6. 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.

  7. 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.

  8. Large-Scale Expansion and Differentiation of Mesenchymal Stem Cells in Microcarrier-Based Stirred Bioreactors.

    PubMed

    Sart, Sébastien; Agathos, Spiros N

    2016-01-01

    Mesenchymal stem cells (MSCs) have emerged as an important tool for tissue engineering, thanks to their differentiation potential and their broad trophic activities. However, for clinical purposes or for relevant in vitro applications, large quantities of MSCs are required, which could hardly be reached using conventional cultivation in plastic dishes. Microcarriers have high surface to volume ratio, which enables the easy scale-up of the expansion and differentiation of MSCs. In addition, the agitation in stirred tank bioreactors limits the diffusion gradient of nutrients or morphogens, thus providing a physiologically relevant environment to favor MSC production at large scale. This work describes a simple method for the mass expansion and differentiation of MSCs, including the procedures to monitor the proliferation, metabolic status and phenotype of MSCs during suspension culture. Moreover, this work proposes suitable materials for cGMP compliant culture conditions enabling the clinical grade production of MSCs.

  9. 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. PMID:26094049

  10. 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.

  11. 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.

  12. Microstructure Characterization and Stress Corrosion Evaluation of Autogenous and Hybrid Friction Stir Welded Al-Cu-Li 2195 Alloy

    NASA Technical Reports Server (NTRS)

    Li, Zhixian; Arbegast, William J.; Meletis, Efstathios I.

    1997-01-01

    Friction stir welding process is being evaluated for application on the Al-Cu-Li 2195 Super-Light Weight External Tank of the Space Transportation System. In the present investigation Al-Cu-Li 2195 plates were joined by autogenous friction stir welding (FSW) and hybrid FSW (friction stir welding over existing variable polarity plasma arc weld). Optical microscopy and transmission electron microscopy (TEM) were utilized to characterize microstructures of the weldments processed by both welding methods. TEM observations of autogenous FSW coupons in the center section of the dynamically-recrystallized zone showed an equiaxed recrystallized microstructure with an average grain size of approx. 3.8 microns. No T(sub 1), precipitates were present in the above-mentioned zone. Instead, T(sub B) and alpha precipitates were found in this zone with a lower population. Alternate immersion, anodic polarization, constant load, and slow strain tests were carried out to evaluate the general corrosion and stress-corrosion properties of autogenous and hybrid FSW prepared coupons. The experimental results will be discussed.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Small angle X-ray scattering studies of CTNNBL1 dimerization and CTNNBL1/CDC5L complex

    PubMed Central

    Ahn, Jae-Woo; Sik Jin, Kyeong; Francis Son, Hyeoncheol; Ho Chang, Jeong; Kim, Kyung-Jin

    2015-01-01

    The hPrp19/CDC5L complex is a non-snRNP spliceosome complex that plays a key role in the spliceosome activation during pre-mRNA splicing, and CTNNBL1 and CDC5L are essential components of the complex. In this study, to investigate the oligomeric state of CTNNBL1 in solution, we performed small angle X-ray scattering experiments in various concentrations of NaCl. We observed that CTNNBL1 existed as a dimer in physiological NaCl concentrations. Site-directed mutagenesis experiment of CTNNBL1 confirmed that N-terminal capping region and the first four ARM repeats are important for dimerization of the protein. We also found that the positively-charged NLS3-containing region (residues 197–235) of CDC5L bound to the negatively-charged patch of CTNNBL1 and that the CTNNBL1/CDC5L complex formed a heterotetramer consisting of one CTNNBL1 dimer and one CDC5L dimer. Moreover, reconstruction of 3D models of CTNNBL1/CDC5L complexes containing CTNNBL1 and three different truncated forms of CDC5L showed that the CDC5L141–196 region and the CDC5L236–377 region were positioned at the top of the N-terminal capping region and at the bottom of ARM VII of CTNNBL1, respectively. PMID:26381213

  20. 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)

  1. 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.

  2. 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.

  3. Friction stir processing on high carbon steel U12

    NASA Astrophysics Data System (ADS)

    Tarasov, S. Yu.; Melnikov, A. G.; Rubtsov, V. E.

    2015-10-01

    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.

  4. 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.

  5. 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.

  6. 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....

  7. NORMATIVE VALUES OF EQ-5D-5L FOR DIABETES PATIENTS FROM SPAIN.

    PubMed

    Collado Mateo, Daniel; García Gordillo, Miguel A; Olivares, Pedro R; Adsuar, José C

    2015-10-01

    Introducción: la diabetes es una enfermedad metabólica que puede conllevar una reducción de la calidad de vida relacionada con la salud. El EQ-5D es un cuestionario genérico de calidad de vida relacionada con la salud basado en preferencias sociales. Este cuestionario ha sido muy utilizado en pacientes con diabetes. Objetivo: el objetivo del presente artículo es informar sobre los valores normativos del cuestionario EQ-5D-5L en personas españolas con diabetes. Métodos: se utilizaron datos de la Encuesta Española de Salud (2011/2012). Un total de 1.857 personas con diabetes participaron en la encuesta. La puntuación del EQ-5D-5L se ha reflejado en función del sexo, región (incluyendo las 17 comunidades autónomas y las 2 ciudades autónomas de España), y 8 grupos de edad. Resultados: la media del índice de utilidad para toda la muestra fue de 0,742. Esta fue mejor para hombres (0,826) que para mujeres (0,673). Resultados similares se observaron en la Escala Visual Analógica. El efecto techo fue mucho mayor en hombres (44,83%) que en mujeres (24,41%). Conclusiones: el presente estudio recoge datos normativos representativos del EQ-5D-5L en España de personas con diabetes.

  8. Tank 241-AX-104 tank characterization plan

    SciTech Connect

    Sathyanarayana, P.

    1994-08-26

    This document is a plan which serves as the contractual agreement between the Characterization Program, Sampling Operations, WHC 222-S Laboratory, and PNL 325 Analytical Chemistry Laboratory. The scope of this plan is to provide guidance for the sampling and analysis of auger samples from tank 241-AX-104.

  9. 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.

  10. 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.

  11. Inhibitive Performance of Monoethylene Glycol on CO2 Corrosion of API 5L X52 Steel

    NASA Astrophysics Data System (ADS)

    Javidi, M.; Khodaparast, M.

    2015-04-01

    Monoethylene glycol has been utilized in wet natural gas transportation to avoid hydrate formation and corrosion. The inhibitive performance of monoethylene glycol (MEG) on CO2 corrosion of API 5L X52 steel in saline solution at 50 °C was studied using electrochemical techniques. Change in inhibition mechanism of MEG against CO2 corrosion was observed including the blocking of reaction sites by MEG in low concentration and slow down of corrosion reactions at high concentration. The presence of different concentrations of sodium chloride affects the corrosion rate in a different manner for rich and lean glycol solution.

  12. 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

  13. Evidence of induced chirality in stirred solutions of supramolecular nanofibers.

    PubMed

    Arteaga, Oriol; Canillas, Adolf; Purrello, Roberto; Ribó, Josep M

    2009-07-15

    Two-modulator generalized ellipsometry is used to determine the spectroscopic Mueller matrix of a solution of porphyrin supramolecular aggregates that have fibrous form. During the measurements the solutions were stirred in clockwise and anticlockwise directions. The pseudopolar decompostion is applied to the experimental Mueller matrices to unveil the birefringent and dichroics properties of the sample. The vortex flow in the stirred solution is found to modify the optical response of the aggregates to polarized light, and, in particular, its chiral signature is determined by the stirring direction in a totally reversible process. The data found show that chirality can be induced by stirring in solutions of supramolecular fibers and that a effective transfer of chirality from a macroscopic phenomenon to the supramolecular structures takes place. PMID:19823540

  14. Friction Stir Spot Welding of DP780 Carbon Steel

    SciTech Connect

    Santella, M. L.; Hovanski, Yuri; Frederick, Alan; Grant, Glenn J.; Dahl, Michael E.

    2009-09-15

    Friction stir spot welds were made in uncoated and galvannneled DP780 sheets using polycrystalline boron nitride stir tools. The tools were plunged at either a single continuous rate or in two segments consisting of a relatively high rate followed by a slower rate of shorter depth. Welding times ranged from 1-10 s. Increasing tool rotation speed from 800 to 1600 rpm increased strength values. The 2-segment welding procedures also produced higher strength joints. Average lap-shear strengths exceeding 10.3 kN were consistently obtained in 4 s on both the uncoated and the galvannealed DP780. The likelihood of diffusion and mechanical interlocking contributing to bond formation was supported by metallographic examinations. A cost analysis based on spot welding in automobile assembly showed that for friction stir spot welding to be economically competitive with resistance spot welding the cost of stir tools must approach that of resistance spot welding electrode tips.

  15. 17. DETAIL VIEW OF WHAT APPEARS TO BE STIRRING FORK ...

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

    17. DETAIL VIEW OF WHAT APPEARS TO BE STIRRING FORK THAT MIXED COFFEE BEANS AS THEY WERE HUSKED - Hacienda Cafetalera Santa Clara, Coffee Mill, KM 19, PR Route 372, Hacienda La Juanita, Yauco Municipio, PR

  16. Condensed-matter physics: History matters for a stirred superfluid

    NASA Astrophysics Data System (ADS)

    Davis, Matthew J.; Helmerson, Kristian

    2014-02-01

    The observation of path dependence in the response of a superfluid to stirring promises potential applications in precision rotation sensing, and provides a test bed for microscopic theories of ultracold atomic gases. See Letter p.200

  17. 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

  18. 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.

  19. 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.

  20. Friction Stir Processing for Efficient Manufacturing

    SciTech Connect

    Mr. Christopher B. Smith; Dr. Oyelayo Ajayi

    2012-01-31

    Friction at contacting surfaces in relative motion is a major source of parasitic energy loss in machine systems and manufacturing processes. Consequently, friction reduction usually translates to efficiency gain and reduction in energy consumption. Furthermore, friction at surfaces eventually leads to wear and failure of the components thereby compromising reliability and durability. In order to reduce friction and wear in tribological components, material surfaces are often hardened by a variety of methods, including conventional heat treatment, laser surface hardening, and thin-film coatings. While these surface treatments are effective when used in conjunction with lubrication to prevent failure, they are all energy intensive and could potentially add significant cost. A new concept for surface hardening of metallic materials and components is Friction Stir Processing (FSP). Compared to the current surface hardening technologies, FSP is more energy efficient has no emission or waste by products and may result in better tribological performance. FSP involves plunging a rotating tool to a predetermined depth (case layer thickness) and translating the FSP tool along the area to be processed. This action of the tool produces heating and severe plastic deformation of the processed area. For steel the temperature is high enough to cause phase transformation, ultimately forming hard martensitic phase. Indeed, FSP has been used for surface modification of several metals and alloys so as to homogenize the microstructure and refine the grain size, both of which led to improved fatigue and corrosion resistance. Based on the effect of FSP on near-surface layer material, it was expected to have beneficial effects on friction and wear performance of metallic materials. However, little or no knowledge existed on the impact of FSP concerning friction and wear performance the subject of the this project and final report. Specifically for steel, which is the most dominant

  1. Thermo-Mechanical Processing in Friction Stir Welds

    NASA Technical Reports Server (NTRS)

    Schneider, J. A.; Nunes, A. C., Jr.

    2002-01-01

    In Friction Stir Welding (FSW) a rotating pin-tool inserted into a weld seam literally stirs the edges of the seam together. In this study, two flow paths are proposed that define the FWS zone. Studies using a longitudinal tungsten wire (0.0025 dia.) were used to visualize and document the material flow. The material flow path is described using a mathematical model.

  2. 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.

  3. Mathematical model for ethanol production by extractive fermentation in a continuous stirred tank fermentor

    SciTech Connect

    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 flow rates entering and leaving the system, since it was found that the aqueous outlet flow rate could be up to 35% lower than the inlet flow rate 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/sup -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.

  4. Performance and simulation of ozone absorption and reactions in a stirred-tank reactor.

    PubMed

    Qiu, Y; Kuo, C H; Zappi, M E

    2001-01-01

    This research investigates the mass transport of gaseous ozone accompanied by decomposition and ozonation reactions in the liquid phase. Absorption experiments were carried out under semibatch mode by continued injection of gaseous ozone into an agitated vessel containing an aqueous solution of 2,4- or 2,6-dichlorophenol at 25 degrees C. Under the influence of a fast reaction between the dissolved ozone and dichlorophenol, the mass transfer rate of ozone is enhanced greatly resulting in rapid destruction of the dichlorophenol. Simulations of the experimental results suggest that the complete mixing model can be applied to describe the fluid flow patterns in both the gas and liquid phases. The results of this study indicate that dichlorophenols can be removed effectively from aqueous solutions of pH near neutrality and that there is little additional advantage in carrying out the treatment process in alkaline solutions.

  5. 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.

  6. 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

  7. Quantification of brewers' yeast flocculation in a stirred tank: effect of physical parameters on flocculation.

    PubMed

    van Hamersveld, E H; van der Lans, R G; Luyben, K C

    1997-10-20

    Quantification of yeast flocculation under defined conditions will help to understand the physical mechanisms of the flocculation process used in beer fermentation. Flocculation was quantified by measuring the size of yeast flocs and the number of single cells. For this purpose, a method to measure floc size and number of single cells in situ was developed. In this way, it was possible to quantify the actual flocculation during fermentation, without influencing flocculation. The effects of three physical parameters, floc strength, fluid shear, and yeast cell concentration, on flocculation during beer fermentation, were examined. Increasing floc strength results in larger flocs and lower numbers of single cells. If the fluid shear is increased, the size of the flocs decreases, and the number of single cells remains constant at approximately 10% of the total cells present. The cell concentration also influences flocculation, a reduction of 50% in cell concentration leads to a decrease of about 25% in floc size. The number of single cells decreases in linear proportion to the cell concentration. This means that, during yeast settling at full scale, the number of single cells decreases. The results of this study are used in a model for yeast flocculation. With respect to full scale fermentation the effect of cell concentration will play an important role, for flocculation and sedimentation will occur simultaneously leading to a quasi steady state between these phenomena. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 190-200, 1997.

  8. Suppressing the Neurospora crassa circadian clock while maintaining light responsiveness in continuous stirred tank reactors.

    PubMed

    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.

  9. The human CD5L/AIM-CD36 axis: A novel autophagy inducer in macrophages that modulates inflammatory responses.

    PubMed

    Sanjurjo, Lucía; Amézaga, Núria; Aran, Gemma; Naranjo-Gómez, Mar; Arias, Lilibeth; Armengol, Carolina; Borràs, Francesc E; Sarrias, Maria-Rosa

    2015-01-01

    CD5L (CD5 molecule-like) is a secreted glycoprotein that participates in host response to bacterial infection. CD5L influences the monocyte inflammatory response to the bacterial surface molecules lipopolysaccharide (LPS) and lipoteichoic acid (LTA) by inhibiting TNF secretion. Here we studied the intracellular events that lead to macrophage TNF inhibition by human CD5L. To accomplish this goal, we performed functional analyses with human monocytic THP1 macrophages, as well as with peripheral blood monocytes. Inhibition of phosphatidylinositol 3-kinase (PtdIns3K) reversed the inhibitory effect of CD5L on TNF secretion. Among the various PtdIns3K isoforms, our results indicated that CD5L activates PtdIns3K (whose catalytic subunit is termed PIK3C3), a key modulator involved in autophagy. Further analysis revealed a concomitant enhancement of autophagy markers such as cellular LC3-II content, increased LC3 puncta, as well as LC3-LysoTracker Red colocalization. Moreover, electron microscopy showed an increased presence of cytosolic autophagosomes in THP1 macrophages overexpressing CD5L. Besides preventing TNF secretion, CD5L also inhibited IL1B and enhanced IL10 secretion. This macrophage anti-inflammatory pattern of CD5L was reverted upon silencing of autophagy protein ATG7 by siRNA transfection. Additional siRNA experiments in THP1 macrophages indicated that the induction of autophagy mechanisms by CD5L was achieved through cell-surface scavenger receptor CD36, a multiligand receptor expressed in a wide variety of cell types. Our data represent the first evidence that CD36 is involved in autophagy and point to a significant contribution of the CD5L-CD36 axis to the induction of macrophage autophagy.

  10. The human CD5L/AIM-CD36 axis: A novel autophagy inducer in macrophages that modulates inflammatory responses.

    PubMed

    Sanjurjo, Lucía; Amézaga, Núria; Aran, Gemma; Naranjo-Gómez, Mar; Arias, Lilibeth; Armengol, Carolina; Borràs, Francesc E; Sarrias, Maria-Rosa

    2015-01-01

    CD5L (CD5 molecule-like) is a secreted glycoprotein that participates in host response to bacterial infection. CD5L influences the monocyte inflammatory response to the bacterial surface molecules lipopolysaccharide (LPS) and lipoteichoic acid (LTA) by inhibiting TNF secretion. Here we studied the intracellular events that lead to macrophage TNF inhibition by human CD5L. To accomplish this goal, we performed functional analyses with human monocytic THP1 macrophages, as well as with peripheral blood monocytes. Inhibition of phosphatidylinositol 3-kinase (PtdIns3K) reversed the inhibitory effect of CD5L on TNF secretion. Among the various PtdIns3K isoforms, our results indicated that CD5L activates PtdIns3K (whose catalytic subunit is termed PIK3C3), a key modulator involved in autophagy. Further analysis revealed a concomitant enhancement of autophagy markers such as cellular LC3-II content, increased LC3 puncta, as well as LC3-LysoTracker Red colocalization. Moreover, electron microscopy showed an increased presence of cytosolic autophagosomes in THP1 macrophages overexpressing CD5L. Besides preventing TNF secretion, CD5L also inhibited IL1B and enhanced IL10 secretion. This macrophage anti-inflammatory pattern of CD5L was reverted upon silencing of autophagy protein ATG7 by siRNA transfection. Additional siRNA experiments in THP1 macrophages indicated that the induction of autophagy mechanisms by CD5L was achieved through cell-surface scavenger receptor CD36, a multiligand receptor expressed in a wide variety of cell types. Our data represent the first evidence that CD36 is involved in autophagy and point to a significant contribution of the CD5L-CD36 axis to the induction of macrophage autophagy. PMID:25713983

  11. Mechanism for Self-Reacted Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Venable, Richard; Bucher, Joseph

    2004-01-01

    A mechanism has been designed to apply the loads (the stirring and the resection forces and torques) in self-reacted friction stir welding. This mechanism differs somewhat from mechanisms used in conventional friction stir welding, as described below. The tooling needed to apply the large reaction loads in conventional friction stir welding can be complex. Self-reacted friction stir welding has become popular in the solid-state welding community as a means of reducing the complexity of tooling and to reduce costs. The main problems inherent in self-reacted friction stir welding originate in the high stresses encountered by the pin-and-shoulder assembly that produces the weld. The design of the present mechanism solves the problems. The mechanism includes a redesigned pin-and-shoulder assembly. The welding torque is transmitted into the welding pin by a square pin that fits into a square bushing with set-screws. The opposite or back shoulder is held in place by a Woodruff key and high-strength nut on a threaded shaft. The Woodruff key reacts the torque, while the nut reacts the tensile load on the shaft.

  12. 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.

  13. Magnetic Properties of Friction Stir Processed Composite

    NASA Astrophysics Data System (ADS)

    Das, Shamiparna; Martinez, Nelson Y.; Das, Santanu; Mishra, Rajiv S.; Grant, Glenn J.; Jana, Saumyadeep; Polikarpov, Evgueni

    2016-07-01

    Of the many existing inspection or monitoring systems, each has its own advantages and drawbacks. These systems are usually comprised of semi-remote sensors that frequently cause difficulty in reaching complex areas of a component. This study proposes to overcome that difficulty by developing embedded functional composites, so that embedding can be achieved in virtually any component part and periodically can be interrogated by a reading device. The "reinforcement rich" processed areas can then be used to record properties such as strain, temperature, and stress state, to name a few, depending on the reinforcement material. Friction stir processing was used to fabricate a magnetostrictive composite by embedding galfenol particles into a nonmagnetic aluminum matrix. The aim was to develop a composite that produces strain in response to a varying magnetic field. Reinforcements were distributed uniformly in the matrix. Magnetization curves were studied using a vibrating sample magnetometer. A simple and cost-effective setup was developed to measure the magnetostrictive strain of the composites. Important factors affecting the magnetic properties were identified and the processing route was modified to improve the magnetic response.

  14. Nondestructive Ultrasonic Inspection of Friction Stir Welds

    NASA Astrophysics Data System (ADS)

    Tabatabaeipour, M.; Hettler, J.; Delrue, S.; Van Den Abeele, K.

    Friction Stir Welding (FSW) is a relatively new solid-state welding procedure developed at The Welding Institute (TWI-UK) and the technique is widely employed for welding aluminum alloys in various applications. In order to examine the quality of the welds and to detect a variety of welding flaws such as wormholes and root-flaws, it is required to develop a methodical inspection technique that can be used for the identification and localization of such defects. The most prevalent and risky defect in this type of welding is the barely visible root flaw with a length varying from 100-700 μm. Due to the extreme characteristics of the flaw, off-the-shelf ultrasonic weld inspection methods are not always able to readily detect this type of minute defect feature. Here, we propose a novel approach to characterize root flaws using an oblique incident ultrasonic C-scan backscattering analysis. The implementation consists of an immersion ultrasonic testing method in pulse echo (i.e. backscatter) mode with a 3.5 MHz transducer, and makes use of an empirical procedure to engender of a shear wave dominated excitation at the root surface, and to properly gate the received signal for root flaw examination. By scanning the surface above the welded component, a C-scan image displaying the backscatter response from the root surface of the nugget zone can be obtained which allows a simple interpretation of the root flaw status of the weld.

  15. Inspecting Friction Stir Welding using Electromagnetic Probes

    NASA Technical Reports Server (NTRS)

    Kinchen, David G.

    2004-01-01

    A report describes the use of advanced electromagnetic probes to measure the dimensions, the spatial distribution of electrical conductivity, and related other properties of friction stir welds (FSWs) between parts made of the same or different aluminum alloy(s). The probes are of the type described in in another Tech Brief. To recapitulate: A probe of this type is essentially an eddy-current probe that includes a primary (driver) winding that meanders and multiple secondary (sensing) windings that meander along the primary winding. Electrical conductivity is commonly used as a measure of heat treatment and tempering of aluminum alloys, but prior to the development of these probes, the inadequate sensitivity and limited accuracy of electrical-conductivity probes precluded such use on FSWs between different aluminum alloys, and the resolution of those probes was inadequate for measurement of FSW dimensions with positions and metallurgical properties. In contrast, the present probes afford adequate accuracy and spatial resolution for the purposes of measuring the dimensions of FSW welds and correlating spatially varying electrical conductivities with metallurgical properties, including surface defects.

  16. The Plunge Phase of Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    McClure, John C.

    2005-01-01

    The many advantages of Friction Stir Welding have led to a relatively rapid acceptance in the often conservative welding community. Because the process is so different from traditional fusion welding, with which most investigators are most familiar, there remain many aspects of FSW for which there is no clear consensus. For example, the well known onion rings seen in transverse sections have been variously interpreted as grain size variations, variation in density of second phase particles and parts of the carousel of material rotating with the pin that have been shed from the carousel. Using Orientation Imaging Microscopy, Schneider has recently noted that the onion rings have a different orientation (and hence etch differently) than the surrounding material, and this orientation is consistent with slip plane orientations at the edge of the carousel. Likewise, the forces and torque exerted by the FSW tool on the work piece largely remain unaccounted for. Although these forces are routinely measured by investigators with commercial instrumented welders, they are rarely reported or even qualitatively analyzed. This paper will introduce a model based on a carousel or disk of material that rotates with the tool to estimate the torque and plunge force required to plunge a tool into the work piece. A stationary tool is modeled rather than the moving tool because effects such as thermal transients and metallurgical changes in the sample (primarily aging in aluminum) can be more easily accounted for. It is believed, however, that with some modifications the model should be applicable to a moving tool also.

  17. 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.

  18. 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.

  19. 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.

  20. Tank waste characterization basis

    SciTech Connect

    Brown, T.M.

    1996-08-09

    This document describes the issues requiring characterization information, the process of determining high priority tanks to obtain information, and the outcome of the prioritization process. In addition, this document provides the reasoning for establishing and revising priorities and plans.

  1. LOX Tank Rupture

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The bright luminous glow at the top is attributed to the rupture of the liquid oxygen tank just above the SRB/ET attachment. At this point, Challenger is completely engulfed in a firey flow of escaping liquid propellant.

  2. 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.

  3. 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).

  4. Liquid Oxygen Tank of the External Tank

    NASA Technical Reports Server (NTRS)

    1978-01-01

    This photograph shows a liquid oxygen tank for the Shuttle External Tank (ET) during a hydroelastic modal survey test at the Marshall Space Flight Center. The ET provides liquid hydrogen and liquid oxygen to the Shuttle's three main engines during the first 8.5 minutes of flight. At 154-feet long and more than 27-feet in diameter, the ET is the largest component of the Space Shuttle, the structural backbone of the entire Shuttle system, and is the only part of the vehicle that is not reusable. The ET is manufactured at the Michoud Assembly Facility near New Orleans, Louisiana, by the Martin Marietta Corporation under management of the Marshall Space Flight Center.

  5. Application of Celluclast 1.5L in apple pectin extraction.

    PubMed

    Wikiera, Agnieszka; Mika, Magdalena; Starzyńska-Janiszewska, Anna; Stodolak, Bożena

    2015-12-10

    Pectins were extracted from apple pomace with Celluclast 1.5L at a dose of 25, 50 and 75 μl per 1g of material. In obtained pectin, the galacturonic acid (GalA) content, the neutral sugars (NS) profile, the degree of methylation (DM) and acetylation (DAc), the molecular mass, protein, ash and polyphenol levels as well as antioxidant and antitumor activity were determined. The lowest dose of enzymatic preparation resulted in the yield of pectin isolation comparable with acidic treatment (15.3%). Application of higher dose caused further, almost 4% increase in polymer recovery. Enzymatically isolated pectin was characterised by larger molecular mass and contained more GalA of higher DM and DAc than polymer extracted with acid. It was also richer in protein and polyphenols, and had different NS profile, which resulted in higher antiradical activity as well as the ability to inhibit the proliferation and invasion of Caco-2 adenocarcinoma cells. PMID:26428122

  6. Application of Celluclast 1.5L in apple pectin extraction.

    PubMed

    Wikiera, Agnieszka; Mika, Magdalena; Starzyńska-Janiszewska, Anna; Stodolak, Bożena

    2015-12-10

    Pectins were extracted from apple pomace with Celluclast 1.5L at a dose of 25, 50 and 75 μl per 1g of material. In obtained pectin, the galacturonic acid (GalA) content, the neutral sugars (NS) profile, the degree of methylation (DM) and acetylation (DAc), the molecular mass, protein, ash and polyphenol levels as well as antioxidant and antitumor activity were determined. The lowest dose of enzymatic preparation resulted in the yield of pectin isolation comparable with acidic treatment (15.3%). Application of higher dose caused further, almost 4% increase in polymer recovery. Enzymatically isolated pectin was characterised by larger molecular mass and contained more GalA of higher DM and DAc than polymer extracted with acid. It was also richer in protein and polyphenols, and had different NS profile, which resulted in higher antiradical activity as well as the ability to inhibit the proliferation and invasion of Caco-2 adenocarcinoma cells.

  7. Thermal Stir Welding Development at Marshall Space Flight Center

    NASA Technical Reports Server (NTRS)

    Ding, Robert J.

    2008-01-01

    Solid state welding processes have become the focus of welding process development at NASA's Marshall Space Flight Center. Unlike fusion weld processes such as tungsten inert gas (TIG), variable polarity plasma arc (VPPA), electron beam (EB), etc., solid state welding processes do not melt the material during welding. The resultant microstructure can be characterized as a dynamically recrystallized morphology much different than the casted, dentritic structure typical of fusion weld processes. The primary benefits of solid state processes over fusion weld processes include superior mechanic properties and the elimination of thermal distortion and residual stresses. These solid state processes attributes have profoundly influenced the direction of advanced welding research and development within the NASA agency. Thermal Stir Welding (TSW) is a new solid state welding process being developed at the Marshall Space Flight Center. Unlike friction stir welding, the heating, stirring and forging elements of the weld process can be decoupled for independent control. An induction coil induces energy into a workpiece to attain a desired plastic temperature. An independently controlled stir rod, captured within non-rotating containment plates, then stirs the plasticized material followed by forging plates/rollers that work the stirred weld joint. The independent control (decoupling) of heating, stirring and forging allows, theoretically, for the precision control of microstructure morphology. The TSW process is being used to evaluate the solid state joining of Haynes 230 for ARES J-2X applications. It is also being developed for 500-in (12.5 mm) thick commercially pure grade 2 titanium for navy applications. Other interests include Inconel 718 and stainless steel. This presentation will provide metallurgical and mechanical property data for these high melting temperature alloys.

  8. 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.

  9. Vitrification of simulated radioactive Rocky Flats plutonium containing ash residue with a Stir Melter System

    SciTech Connect

    Marra, J.C.; Kormanyos, K.R.; Overcamp, T.J.

    1996-10-01

    A demonstration trial has been completed in which a simulated Rocky Flats ash consisting of an industrial fly-ash material doped with cerium oxide was vitrified in an alloy tank Stir-Melter{trademark} System. The cerium oxide served as a substitute for plutonium oxide present in the actual Rocky Flats residue stream. The glass developed falls within the SiO{sub 2} + Al{sub 2}O{sub 3}/{Sigma}Alkali/B{sub 2}O{sub 3} system. The glass batch contained approximately 40 wt% of ash, the ash was modified to contain {approximately} 5 wt% CeO{sub 2} to simulate plutonium chemistry in the glass. The ash simulant was mixed with water and fed to the Stir-Melter as a slurry with a 60 wt% water to 40 wt% solids ratio. Glass melting temperature was maintained at approximately 1,050 C during the melting trials. Melting rates as functions of impeller speed and slurry feed rate were determined. An optimal melting rate was established through a series of evolutionary variations of the control variables` settings. The optimal melting rate condition was used for a continuous six hour steady state run of the vitrification system. Glass mass flow rates of the melter were measured and correlated with the slurry feed mass flow. Melter off-gas was sampled for particulate and volatile species over a period of four hours during the steady state run. Glass composition and durability studies were run on samples collected during the steady state run.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Nanoscale magnetic stirring bars for heterogeneous catalysis in microscopic systems.

    PubMed

    Yang, Shuliang; Cao, Changyan; Sun, Yongbin; Huang, Peipei; Wei, Fangfang; Song, Weiguo

    2015-02-23

    Nanometer-sized magnetic stirring bars containing Pd nanoparticles (denoted as Fe3 O4 -NC-PZS-Pd) for heterogeneous catalysis in microscopic system were prepared through a facile two-step process. In the hydrogenation of styrene, Fe3 O4 -NC-PZS-Pd showed an activity similar to that of the commercial Pd/C catalyst, but much better stability. In microscopic catalytic systems, Fe3 O4 -NC-PZS-Pd can effectively stir the reaction solution within microdrops to accelerate mass transfer, and displays far better catalytic activity than the commercial Pd/C for the hydrogenation of methylene blue in an array of microdroplets. These results suggested that the Fe3 O4 -NC-PZS-Pd could be used as nanoscale stirring bars in nanoreactors.

  15. A Brief Introduction to the Theory of 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 is already an important welding process for the aerospace industry, where welds of optimal quality are demanded. The structure of welds determines weld properties. The structure of friction stir welds is determined by the flow field in the weld metal in the vicinity of the weld tool. A simple kinematic model of the FSW flow field developed at Marshall Space Flight Center, which enables the basic features of FSW microstructure to be understood and related to weld process parameters and tool design, is explained.

  16. Wet gringing of zeolite in stirred media mill

    NASA Astrophysics Data System (ADS)

    Mucsi, G.; Bohács, K.

    2016-04-01

    In the present study the results of systematic experimental series are presented with the specific goal of optimizing the zeolite nanoparticles' production using a wet stirred media mill. The diameter of the grinding media as well as the rotor velocity were varied in the experiments. Particle size distribution and "outer" specific surface area of the ground samples were measured by a laser particle size analyser. Additionally, BET, XRD and FT-IR analyses were performed for the characterization of the "total" specific surface area as well as the crystalline and material structure, respectively. Based on the results of the laboratory experiments it was found that wet stirred media milling provided significant reductions in the particle size of zeolite. Furthermore, the crystallinity of the samples also decreased, so not only the physical but the mineralogical characteristics of zeolite can be controlled by stirred media milling.

  17. Vortex excitation in a stirred toroidal Bose-Einstein condensate

    NASA Astrophysics Data System (ADS)

    Yakimenko, A. I.; Isaieva, K. O.; Vilchinskii, S. I.; Ostrovskaya, E. A.

    2015-02-01

    Motivated by a recent experiment [K. C. Wright et al., Phys. Rev. A 88, 063633 (2013), 10.1103/PhysRevA.88.063633], we investigate the microscopic mechanism for excitation of vortices and formation of a persistent current in an annular BEC stirred by a narrow blue-detuned optical beam. In the framework of a two-dimensional mean-field model, we study the dissipative dynamics of the condensate with parameters that reflect realistic experimental conditions. Vortex-antivortex pairs appear near the center of the stirrer in the bulk of the condensate for slow motion of the stirring beam. When the barrier angular velocity is above some critical value, an outer edge surface mode develops and breaks into the vortices entering the condensate annulus. We determine the conditions for creation of vortex excitations in the stirred toroidal condensate and compare our results with experimental observations.

  18. Weld Nugget Temperature Control in Thermal Stir Welding

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey (Inventor)

    2014-01-01

    A control system for a thermal stir welding system is provided. The control system includes a sensor and a controller. The sensor is coupled to the welding system's containment plate assembly and generates signals indicative of temperature of a region adjacent and parallel to the welding system's stir rod. The controller is coupled to the sensor and generates at least one control signal using the sensor signals indicative of temperature. The controller is also coupled to the welding system such that at least one of rotational speed of the stir rod, heat supplied by the welding system's induction heater, and feed speed of the welding system's weld material feeder are controlled based on the control signal(s).

  19. External Tank Assembly

    NASA Technical Reports Server (NTRS)

    1977-01-01

    This photograph shows the liquid hydrogen tank and liquid oxygen tank for the Space Shuttle external tank (ET) being assembled in the weld assembly area of the Michoud Assembly Facility (MAF). The ET provides liquid hydrogen and liquid oxygen to the Shuttle's three main engines during the first eight 8.5 minutes of flight. At 154-feet long and more than 27-feet in diameter, the ET is the largest component of the Space Shuttle, the structural backbone of the entire Shuttle system, and the only part of the vehicle that is not reusable. The ET is manufactured at the Michoud Assembly Facility near New Orleans, Louisiana, by the Martin Marietta Corporation under management of the Marshall Space Flight Center.

  20. Heat Control via Torque Control in Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Venable, Richard; Colligan, Kevin; Knapp, Alan

    2004-01-01

    In a proposed advance in friction stir welding, the torque exerted on the workpiece by the friction stir pin would be measured and controlled in an effort to measure and control the total heat input to the workpiece. The total heat input to the workpiece is an important parameter of any welding process (fusion or friction stir welding). In fusion welding, measurement and control of heat input is a difficult problem. However, in friction stir welding, the basic principle of operation affords the potential of a straightforward solution: Neglecting thermal losses through the pin and the spindle that supports it, the rate of heat input to the workpiece is the product of the torque and the speed of rotation of the friction stir weld pin and, hence, of the spindle. Therefore, if one acquires and suitably processes data on torque and rotation and controls the torque, the rotation, or both, one should be able to control the heat input into the workpiece. In conventional practice in friction stir welding, one uses feedback control of the spindle motor to maintain a constant speed of rotation. According to the proposal, one would not maintain a constant speed of rotation: Instead, one would use feedback control to maintain a constant torque and would measure the speed of rotation while allowing it to vary. The torque exerted on the workpiece would be estimated as the product of (1) the torque-multiplication ratio of the spindle belt and/or gear drive, (2) the force measured by a load cell mechanically coupled to the spindle motor, and (3) the moment arm of the load cell. Hence, the output of the load cell would be used as a feedback signal for controlling the torque (see figure).

  1. 33 CFR 157.15 - Slop tanks in tank vessels.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... affecting § 157.15, see the List of CFR Sections Affected, which appears in the Finding Aids section of the... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Slop tanks in tank vessels. 157... (CONTINUED) POLLUTION RULES FOR THE PROTECTION OF THE MARINE ENVIRONMENT RELATING TO TANK VESSELS...

  2. 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.

  3. 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.

  4. Computational Fluid Dynamics (CFD) Simulations on Multiphase Flow in Mechanically Agitated Seed Precipitation Tank

    NASA Astrophysics Data System (ADS)

    Zhao, Hong-Liang; Liu, Yan; Zhang, Ting-An; Gu, Songqing; Zhang, Chao

    2014-07-01

    The large-scale mechanically agitated tank has been widely used in the decomposition process of sodium aluminate solution in the alumina industry. The mixing process in three types of seed precipitation tanks (Robin, Ekato, and improved Ekato) stirred with multiple impellers was compared by using computational fluid dynamics, respectively. The flow field, solid distribution, mixing time, and power consumption were numerically simulated by adopting a Eulerian granular multiphase model and a standard k- ɛ turbulence model. A steady multiple reference frame approach was used to represent impeller rotation. Compared with the Robin tank, the Ekato tank can generate an axial circulation loop, which is better for fluid mixing and solid suspension; meanwhile about half of the power can be saved. With future improvements in the Ekato tank, the fluid mixing and exchanging can be enhanced under the interaction of a lengthened Intermig impeller coupled with sloped baffles. With a little increase in power consumption, the maximum of the relative solid concentration difference in the whole tank can be maintained within 3%, which meets the design requirement.

  5. Characterization of the Micro Textures in a Friction Stir Weld

    NASA Technical Reports Server (NTRS)

    Schneider, Judy; Nunes, Arthur C.

    2004-01-01

    In friction stir welding (FSW), a rotating threaded pin tool is inserted into a weld seam and literally stirs the edges of the seam together. The Dynamically-Recrystallized-Zone (DXZ) of a polished and etched FSW cross-section exhibits contrasting bands (the "onion-ring" structure), the origins of which are unclear. An orientation image mapping (OIM) study suggests that the corresponding bands may correspond respectively to a "straight-through" current of metal bypassing the pin tool in a single rotation or less and a "maelstrom" current rotating a number of times around the pin tool.

  6. Friction stir weld tools having fine grain structure

    DOEpatents

    Grant, Glenn J.; Frye, John G.; Kim, Jin Yong; Lavender, Curt A.; Weil, Kenneth Scott

    2016-03-15

    Tools for friction stir welding can be made with fewer process steps, lower cost techniques, and/or lower cost ingredients than other state-of-the-art processes by utilizing improved compositions and processes of fabrication. Furthermore, the tools resulting from the improved compositions and processes of fabrication can exhibit better distribution and homogeneity of chemical constituents, greater strength, and/or increased durability. In one example, a friction stir weld tool includes tungsten and rhenium and is characterized by carbide and oxide dispersoids, by carbide particulates, and by grains that comprise a solid solution of the tungsten and rhenium. The grains do not exceed 10 micrometers in diameter.

  7. Near Net Manufacturing Using Thin Gage Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Takeshita, Jennifer; Potter, David; Holquin, Michael

    2006-01-01

    Friction Stir Welding (FSW) and near net spin forming of FSW aluminumn blanks were investigated for large-scale pressure vessel applications. With a specific focus on very thin gage 2xxx and 7xxx aluminum alloys, the program concentrated on the following: the criteria used for material selection, a potential manufacturing flow, and the effectiveness and associated risks of near net spin forming. Discussion will include the mechanical properties of the friction stir welds and the parent material from before and after the spin forming process. This effort was performed under a NASA Space Exploration initiative focused on increasing the affordability, reliability and performance of pressure vessels larger than 10 ft. diameter.

  8. Unraveling the Processing Parameters in Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Schneider, Judy; Nunes, Arthur C., Jr.

    2005-01-01

    In friction stir welding (FSW), a rotating threaded pin tool is translated along a weld seam, literally stirring the edges of the seam together. To determine optimal processing parameters for producing a defect free weld, a better understanding of the resulting metal deformation flow path or paths is required. In this study, various markers are used to trace the flow paths of the metal. X-ray radiographs record the segmentation and position of the wire. Several variations in the trajectories can be differentiated within the weld zone.

  9. 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.'

  10. Robotic Manufacturing of 18-ft (5.5m) Diameter Cryogenic Fuel Tank Dome Assemblies for the NASA Ares I Rocket

    NASA Technical Reports Server (NTRS)

    Jones, Ronald E.; Carter, Robert W.

    2012-01-01

    The Ares I rocket was the first launch vehicle scheduled for manufacture under the National Aeronautic and Space Administration's Constellation program. A series of full-scale Ares I development articles were constructed on the Robotic Weld Tool at the NASA George C. Marshall Space Flight Center in Huntsville, Alabama. The Robotic Weld Tool is a 100 ton, 7- axis, robotic manufacturing system capable of machining and friction stir welding large-scale space hardware. This paper will focus on the friction stir welding of 18-ft (5.5m) diameter cryogenic fuel tank components; specifically, the liquid hydrogen forward dome and two common bulkhead manufacturing development articles.

  11. Urinary excretion of 5-L-oxoproline (pyroglutamic acid) is increased in normal adults consuming vegetarian or low protein diets.

    PubMed

    Jackson, A A; Persaud, C; Meakins, T S; Bundy, R

    1996-11-01

    A method for measuring 5-L-oxoproline in urine, which involves isolation by short-column chromatography, acid hydrolysis to glutamic acid and enzymic assay of glutamic acid, was used to measure the rate of excretion in normal adults, aged 20 to 45 y. There was no difference in the daily excretion between omnivorous males (217 micromol/d) and females (195 micromol/d). In vegetarian males, urinary 5-L-oxoproline (404 micromol/d) was significantly greater than in vegetarian females (267 micromol/d, P = 0.013). Compared with omnivorous males or females, excretion of 5-L-oxoproline was significantly greater in vegetarian males (P < 0.0001) and females (P= 0.005). When normal adults consumed a diet in which the protein content was controlled at either 4.0 or 6.2 g N/d for 5 d, there was a significant increase in urinary 5-L-oxoproline on d 5, compared with either d 1 or 4. There was a significant inverse linear relationship between the increased urinary 5-L-oxoproline on the fifth dietary day and the nitrogen content of the diet. On the basis of this relationship, when the urinary excretion of 5-L-oxoproline (320 micromol/d) for vegetarians was predicted from an estimate of their dietary intake of nitrogen, the estimate was, on average, close to the measured value (345 micromol/d). As a matter of course, vegetarians excrete more 5-L-oxoproline in urine than do omnivores, and we speculated that this difference might be accounted for by differences in dietary nitrogen and the endogenous capacity for de novo synthesis of glycine.

  12. Space Shuttle ET Friction Stir Weld Machines

    NASA Technical Reports Server (NTRS)

    Thompson, Jack M.

    2003-01-01

    NASA and Lockheed-Martin approached the FSW machine vendor community with a specification for longitudinal barrel production FSW weld machines and a shorter travel process development machine in June of 2000. This specification was based on three years of FSW process development on the Space Shuttle External Tank alloys, AL2 195-T8M4 and AL22 19-T87. The primary motivations for changing the ET longitudinal welds from the existing variable polarity Plasma Arc plasma weld process included: (1) Significantly reduced weld defect rates and related reduction in cycle time and uncertainty; (2) Many fewer process variables to control (5 vs. 17); (3) Fewer manufacturing steps; (4) Lower residual stresses and distortion; (5) Improved weld strengths, particularly at cryogenic temperatures; (6) Fewer hazards to production personnel. General Tool was the successful bidder. The equipment is at this writing installed and welding flight hardware. This paper is a means of sharing with the rest of the FSW community the unique features developed to assure NASA/L-M of successful production welds.

  13. Tank 50H Flammability Calculations

    SciTech Connect

    Lambert, D.P.

    2003-05-26

    This report presents the results form the Phase 1 testing. Phase 1 was designed to determine the tetraphenylborate decomposition rate of the 4PB present in Tank 50H if Tank 23H or Inhibited Water is added to the tank.

  14. Accelerated Tank Closure Demonstration Project

    SciTech Connect

    SAMS, T.L.

    2003-02-01

    Among the highest priorities for action under the ''Hanford Federal Facility and Agreement and Consent Order'', hereafter referred to as the Tri-Party Agreement, is the retrieval, treatment and disposal of Hanford Site tank waste. Tank waste is recognized as one of the primary threats to the Columbia River and one of the most complex technical challenges. Progress has been made in resolving safety issues, characterizing tank waste and past tank leaks, enhancing double-shell tank waste transfer and operations systems, retrieving single-shell tank waste, deploying waste treatment facilities, and planning for the disposal of immobilized waste product. However, limited progress has been made in developing technologies and providing a sound technical basis for tank system closure. To address this limitation the Accelerated Tank Closure Demonstration Project was created to develop information through technology demonstrations in support of waste retrieval and closure decisions. To complete its mission the Accelerated Tank Closure Demonstration Project has adopted performance objectives that include: protecting human health and the environment; minimizing/eliminating potential waste releases to the soil and groundwater; preventing water infiltration into the tank; maintaining accessibility of surrounding tanks for future closure; maintaining tank structural integrity; complying with applicable waste retrieval, disposal, and closure regulations; and maintaining flexibility for final closure options in the future.

  15. Cascade degradation of organic matters in brewery wastewater using a continuous stirred microbial electrochemical reactor and analysis of microbial communities.

    PubMed

    Wang, Haiman; Qu, Youpeng; Li, Da; Ambuchi, John J; He, Weihua; Zhou, Xiangtong; Liu, Jia; Feng, Yujie

    2016-01-01

    A continuous stirred microbial electrochemical reactor (CSMER), comprising of a complete mixing zone (CMZ) and microbial electrochemical zone (MEZ), was used for brewery wastewater treatment. The system realized 75.4 ± 5.7% of TCOD and 64.9 ± 4.9% of TSS when fed with brewery wastewater concomitantly achieving an average maximum power density of 304 ± 31 m W m(-2). Cascade utilization of organic matters made the CSMER remove a wider range of substrates compared with a continuous stirred tank reactor (CSTR), in which process 79.1 ± 5.6% of soluble protein and 86.6 ± 2.2% of soluble carbohydrates were degraded by anaerobic digestion in the CMZ and short-chain volatile fatty acids were further decomposed and generated current in the MEZ. Co-existence of fermentative bacteria (Clostridium and Bacteroides, 19.7% and 5.0%), acetogenic bacteria (Syntrophobacter, 20.8%), methanogenic archaea (Methanosaeta and Methanobacterium, 40.3% and 38.4%) and exoelectrogens (Geobacter, 12.4%) as well as a clear spatial distribution and syntrophic interaction among them contributed to the cascade degradation process in CSMER. The CSMER shows great promise for practical wastewater treatment application due to high pre-hydrolysis and acidification rate, high energy recovery and low capital cost. PMID:27270788

  16. Cascade degradation of organic matters in brewery wastewater using a continuous stirred microbial electrochemical reactor and analysis of microbial communities.

    PubMed

    Wang, Haiman; Qu, Youpeng; Li, Da; Ambuchi, John J; He, Weihua; Zhou, Xiangtong; Liu, Jia; Feng, Yujie

    2016-06-07

    A continuous stirred microbial electrochemical reactor (CSMER), comprising of a complete mixing zone (CMZ) and microbial electrochemical zone (MEZ), was used for brewery wastewater treatment. The system realized 75.4 ± 5.7% of TCOD and 64.9 ± 4.9% of TSS when fed with brewery wastewater concomitantly achieving an average maximum power density of 304 ± 31 m W m(-2). Cascade utilization of organic matters made the CSMER remove a wider range of substrates compared with a continuous stirred tank reactor (CSTR), in which process 79.1 ± 5.6% of soluble protein and 86.6 ± 2.2% of soluble carbohydrates were degraded by anaerobic digestion in the CMZ and short-chain volatile fatty acids were further decomposed and generated current in the MEZ. Co-existence of fermentative bacteria (Clostridium and Bacteroides, 19.7% and 5.0%), acetogenic bacteria (Syntrophobacter, 20.8%), methanogenic archaea (Methanosaeta and Methanobacterium, 40.3% and 38.4%) and exoelectrogens (Geobacter, 12.4%) as well as a clear spatial distribution and syntrophic interaction among them contributed to the cascade degradation process in CSMER. The CSMER shows great promise for practical wastewater treatment application due to high pre-hydrolysis and acidification rate, high energy recovery and low capital cost.

  17. Cascade degradation of organic matters in brewery wastewater using a continuous stirred microbial electrochemical reactor and analysis of microbial communities

    PubMed Central

    Wang, Haiman; Qu, Youpeng; Li, Da; Ambuchi, John J.; He, Weihua; Zhou, Xiangtong; Liu, Jia; Feng, Yujie

    2016-01-01

    A continuous stirred microbial electrochemical reactor (CSMER), comprising of a complete mixing zone (CMZ) and microbial electrochemical zone (MEZ), was used for brewery wastewater treatment. The system realized 75.4 ± 5.7% of TCOD and 64.9 ± 4.9% of TSS when fed with brewery wastewater concomitantly achieving an average maximum power density of 304 ± 31 m W m−2. Cascade utilization of organic matters made the CSMER remove a wider range of substrates compared with a continuous stirred tank reactor (CSTR), in which process 79.1 ± 5.6% of soluble protein and 86.6 ± 2.2% of soluble carbohydrates were degraded by anaerobic digestion in the CMZ and short-chain volatile fatty acids were further decomposed and generated current in the MEZ. Co-existence of fermentative bacteria (Clostridium and Bacteroides, 19.7% and 5.0%), acetogenic bacteria (Syntrophobacter, 20.8%), methanogenic archaea (Methanosaeta and Methanobacterium, 40.3% and 38.4%) and exoelectrogens (Geobacter, 12.4%) as well as a clear spatial distribution and syntrophic interaction among them contributed to the cascade degradation process in CSMER. The CSMER shows great promise for practical wastewater treatment application due to high pre-hydrolysis and acidification rate, high energy recovery and low capital cost. PMID:27270788

  18. Microhardness and Strain Field Characterization of Self-Reacting Friction Stir and Plug Welds of Dissimilar Aluminum Alloys

    NASA Technical Reports Server (NTRS)

    Horton, Karla Renee

    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. Friction plug welding is used to seal the exit hole that remains in a circumferential SR-FSW. This work reports on material properties and strain patterns developed in a SR-FSW with a friction plug weld. Specifically, this study examines the behavior of a SR-FSW formed between an AA 2014-T6 plate on the advancing side and an AA 2219-T87 plate on the retreating side and a SR-FSW (AA 2014-T6 to AA 2219-T87) with a 2219-T87 plug weld. This study presents the results of a characterization of the micro-hardness, joint strength, and strain field characterization of SR-FSW and FPW joints tested at room temperature and cryogenic temperatures.

  19. Plating Tank Control Software

    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.

  20. 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.

  1. Tank bump consequence analysis

    SciTech Connect

    Board, B.D.

    1996-09-01

    The purpose of this document is to derive radiological and toxicological consequences for a tank bump event based on analysis performed using the GOTH computer model, to estimate the mitigative effect of pump and sluice pit cover blocks, and to discuss preventative measures.

  2. Tank bump consequence analysis

    SciTech Connect

    Board, B.D.

    1996-08-07

    The purpose of this document is to derive radiological and toxicological consequences for a tank bump event based on analysis performed using the GOTH computer model, to estimate the mitigative effect of pump and sluice pit cover blocks, and to discuss preventative measures.

  3. Underground storage tank program

    SciTech Connect

    Lewis, M.W.

    1994-12-31

    Underground storage tanks, UST`S, have become a major component of the Louisville District`s Environmental Support Program. The District`s Geotechnical and Environmental Engineering Branch has spear-headed an innovative effort to streamline the time, effort and expense for removal, replacement, upgrade and associated cleanup of USTs at military and civil work installations. This program, called Yank-A-Tank, creates generic state-wide contracts for removal, remediation, installation and upgrade of storage tanks for which individual delivery orders are written under the basic contract. The idea is to create a ``JOC type`` contract containing all the components of work necessary to remove, reinstall or upgrade an underground or above ground tank. The contract documents contain a set of generic specifications and unit price books in addition to the standard ``boiler plate`` information. Each contract requires conformance to the specific regulations for the state in which it is issued. The contractor`s bid consists of a bid factor which in the multiplier used with the prices in the unit price book. The solicitation is issued as a Request for Proposal (RPP) which allows the government to select a contractor based on technical qualification an well as bid factor. Once the basic contract is awarded individual delivery orders addressing specific areas of work are scoped, negotiated and awarded an modifications to the original contract. The delivery orders utilize the prepriced components and the contractor`s factor to determine the value of the work.

  4. SCATHA measurements of electron decay times at 5 < L ≤ 8

    NASA Astrophysics Data System (ADS)

    Su, Yi-Jiun; Johnston, W. R.; Albert, J. M.; Ginet, G. P.; Starks, M. J.; Roth, C. J.

    2012-08-01

    The electron decay timescale (τ) is well known to be associated with radiation belt loss processes. Knowledge of τ is important for understanding pitch angle and radial diffusion mechanisms. Previous studies reported decay timescales from the inner belt to geosynchronous orbits; however, relatively few statistical studies have been focused on the region beyond the traditional outer belt. In this paper, a systematic calculation of electron decay times at 5 < L ≤ 8 is performed using 11 years (1979-1989) of electron data from the Spacecraft Charging AT High Altitudes (SCATHA) satellite. The decay timescale is determined using daily median fluxes, providing resolution of τ > 1 day. τ is examined as a function of energy, pitch angle, L shell, Kp, and AE during magnetically disturbed periods when Dst ≤ -50 nT. Results show that τ increases with increasing electron energy at L < 6.6 for electron energies from 50 to 300 keV, but is independent of energy at L > 6.6. This suggests radial transport as the dominant effect at L > 6.6. Additionally, τ decreases with increasing L-shell. This dependence has the strongest correlation and is seen in all energies and pitch angles. However,τ has no systematic dependence with pitch angle suggesting that pitch angle diffusion also plays a key role in the electron loss process. Based on our results, τ can be expressed as a function of energy and L, and coefficients are provided for a two-variable fit. Surprisingly,τ is slightly longer for higher activity cases at L < 6.6, which is inconsistent with the current radial or pitch angle diffusion models. Global effective decay times on the timescale of days place an upper bound on the true loss timescale.

  5. Tanks focus area. Annual report

    SciTech Connect

    Frey, J.

    1997-12-31

    The U.S. Department of Energy Office of Environmental Management is tasked with a major remediation project to treat and dispose of radioactive waste in hundreds of underground storage tanks. These tanks contain about 90,000,000 gallons of high-level and transuranic wastes. We have 68 known or assumed leaking tanks, that have allowed waste to migrate into the soil surrounding the tank. In some cases, the tank contents have reacted to form flammable gases, introducing additional safety risks. These tanks must be maintained in the safest possible condition until their eventual remediation to reduce the risk of waste migration and exposure to workers, the public, and the environment. Science and technology development for safer, more efficient, and cost-effective waste treatment methods will speed up progress toward the final remediation of these tanks. The DOE Office of Environmental Management established the Tanks Focus Area to serve as the DOE-EM`s technology development program for radioactive waste tank remediation in partnership with the Offices of Waste Management and Environmental Restoration. The Tanks Focus Area is responsible for leading, coordinating, and facilitating science and technology development to support remediation at DOE`s four major tank sites: the Hanford Site in Washington State, Idaho National Engineering and Environmental Laboratory in Idaho, Oak Ridge Reservation in Tennessee, and the Savannah River Site in South Carolina. The technical scope covers the major functions that comprise a complete tank remediation system: waste retrieval, waste pretreatment, waste immobilization, tank closure, and characterization of both the waste and tank. Safety is integrated across all the functions and is a key component of the Tanks Focus Area program.

  6. 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...

  7. 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...

  8. 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....

  9. 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...

  10. 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...

  11. 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....

  12. 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...

  13. 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)...

  14. 49 CFR 179.500 - Specification DOT-107A * * * * seamless steel tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... car tanks. 179.500 Section 179.500 Transportation Other Regulations Relating to Transportation... 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, 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....

  16. 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....

  17. 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....

  18. 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....

  19. 49 CFR 179.500 - Specification DOT-107A * * * * seamless steel tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... car tanks. 179.500 Section 179.500 Transportation Other Regulations Relating to Transportation...) 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....

  20. 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...

  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. Recent developments in Micro Friction Stir Welding: A review

    NASA Astrophysics Data System (ADS)

    Sithole, Keydon; Vasudeva Rao, Veeredhi

    2016-02-01

    The advent of friction stir welding (FSW) in 1991 has been evolutionary in the joining of metals and related materials. Friction stir welding has enabled the joining of metals that could not be joined by other welding processes. Research has shown that dissimilar materials with very different properties, plastics, composites and even wood can be joined by FSW. Recent activities in the application of FSW has seen the development of micro friction stir welding (μFSW), which is the FSW of very thin sections of thickness 1000 μm (1 mm) or less. Micro friction stir welding further extends the applications of FSW to areas such as copper electrical contacts, tailor-welded blanks, wood. Though μFSW is relatively new development significant work has been done to date with interesting research findings being reported. This paper aims to review developments in μFSW to date. The focus of the paper will be on problems peculiar to μFSW due to downscaling to the micro scale and other practical considerations.

  3. Stirring and mixing of liquids using acoustic radiation force.

    PubMed

    Sarvazyan, Armen; Ostrovsky, Lev

    2009-06-01

    The possibility of using acoustic radiation force in standing waves for stirring and mixing small volumes of liquids is theoretically analyzed. The principle of stirring considered in this paper is based on moving the microparticles suspended in a standing acoustic wave by changing the frequency so that one standing wave mode is replaced by the other, with differently positioned minima of potential energy. The period-average transient dynamics of solid microparticles and gas microbubbles is considered, and simple analytical solutions are obtained for the case of standing waves of variable amplitude. It is shown that bubbles can be moved from one equilibrium position to another two to three orders of magnitude faster than solid particles. For example, radiation force in a standing acoustic wave field may induce movement of microbubbles with a speed of the order of a few m/s at a frequency of 1 MHz and ultrasound pressure amplitude of 100 kPa, whereas the speed of rigid particles does not exceed 1 cms under the same conditions. The stirring effect can be additionally enhanced due to the fact that the bubbles that are larger and smaller than the resonant bubbles move in opposite directions. Possible applications of the analyzed stirring mechanism, such as in microarrays, are discussed. PMID:19507936

  4. Laboratory Experiment for the Transient Response of a Stirred Vessel.

    ERIC Educational Resources Information Center

    Noble, R. D.; And Others

    1983-01-01

    Provides background information, apparatus needed, and procedures for an experiment to measure transient response of a stirred vessel. The inexpensive apparatus can be used for two different experiments, reducing cost per experiment. Both experiments use salt dilution as the method of demonstration. (Author/JN)

  5. Friction Stir Spot Welding of Advanced High Strength Steels

    SciTech Connect

    Santella, M. L.; Hovanski, Yuri; Grant, Glenn J.; Carpenter, Joseph A.; Warren, C. D.; Smith, Mark T.

    2008-12-28

    Experiments are continuing to evaluate the feasibility of friction stir spot welding advanced high-strength steels including, DP780, martensitic hot-stamp boron steel, and TRIP steels. Spot weld lap-shear strengths can exceed those required by industry standards such as AWS D8.1.

  6. Lateral position detection and control for friction stir systems

    DOEpatents

    Fleming, Paul; Lammlein, David; Cook, George E.; Wilkes, Don Mitchell; Strauss, Alvin M.; Delapp, David; Hartman, Daniel A.

    2010-12-14

    A friction stir system for processing at least a first workpiece includes a spindle actuator coupled to a rotary tool comprising a rotating member for contacting and processing the first workpiece. A detection system is provided for obtaining information related to a lateral alignment of the rotating member. The detection system comprises at least one sensor for measuring a force experienced by the rotary tool or a parameter related to the force experienced by the rotary tool during processing, wherein the sensor provides sensor signals. A signal processing system is coupled to receive and analyze the sensor signals and determine a lateral alignment of the rotating member relative to a selected lateral position, a selected path, or a direction to decrease a lateral distance relative to the selected lateral position or selected path. In one embodiment, the friction stir system can be embodied as a closed loop tracking system, such as a robot-based tracked friction stir welding (FSW) or friction stir processing (FSP) system.

  7. Defect Detectability Improvement for Conventional Friction Stir Welds

    NASA Technical Reports Server (NTRS)

    Hill, Chris

    2013-01-01

    This research was conducted to evaluate the effects of defect detectability via phased array ultrasound technology in conventional friction stir welds by comparing conventionally prepped post weld surfaces to a machined surface finish. A machined surface is hypothesized to improve defect detectability and increase material strength.

  8. The Care Tradition: Beyond "Add Women and Stir."

    ERIC Educational Resources Information Center

    Noddings, Nel

    2001-01-01

    Examines problems of curricular inclusion, emphasizing ways of including the interests and contributions of women in social studies curricula. After describing the inadequacy of the "add women and stir" approach to inclusion, the paper discusses the tradition of care long identified with female life, then explores ways to preserve and extend this…

  9. Friction Stir Spot Welding of DP780 Carbon Steel

    SciTech Connect

    Santella, Michael L; Hovanski, Yuri; Frederick, David Alan; Grant, Glenn J; Dahl, Michael E

    2010-01-01

    Friction stir spot welds were made in uncoated and galvannealed DP780 sheets using polycrystalline boron nitride stir tools. The tools were plunged at either a single continuous rate or in two segments consisting of a relatively high rate followed by a slower rate of shorter depth. Welding times ranged from 1 to 10 s. Increasing tool rotation speed from 800 to 1600 rev min{sup -1} increased strength values. The 2-segment welding procedures also produced higher strength joints. Average lap shear strengths exceeding 10 {center_dot} 3 kN were consistently obtained in 4 s on both the uncoated and the galvannealed DP780. The likelihood of diffusion and mechanical interlocking contributing to bond formation was supported by metallographic examinations. A cost analysis based on spot welding in automobile assembly showed that for friction stir spot welding to be economically competitive with resistance spot welding the cost of stir tools must approach that of resistance spot welding electrode tips.

  10. Temporarily alloying titanium to facilitate friction stir welding

    SciTech Connect

    Hovanski, Yuri

    2009-05-01

    While historically hydrogen has been considered an impurity in titanium, when used as a temporary alloying agent it promotes beneficial changes to material properties that increase the hot-workability of the metal. This technique known as thermohydrogen processing was used to temporarily alloy hydrogen with commercially pure titanium sheet as a means of facilitating the friction stir welding process. Specific alloying parameters were developed to increase the overall hydrogen content of the titanium sheet ranging from commercially pure to 30 atomic percent. Each sheet was evaluated to determine the effect of the hydrogen content on process loads and tool deformation during the plunge phase of the friction stir welding process. Two materials, H-13 tool steel and pure tungsten, were used to fabricate friction stir welding tools that were plunged into each of the thermohydrogen processed titanium sheets. Tool wear was characterized and variations in machine loads were quantified for each tool material and weld metal combination. Thermohydrogen processing was shown to beneficially lower plunge forces and stabilize machine torques at specific hydrogen concentrations. The resulting effects of hydrogen addition to titanium metal undergoing the friction stir welding process are compared with modifications in titanium properties documented in modern literature. Such comparative analysis is used to explain the variance in resulting process loads as a function of the initial hydrogen concentration of the titanium.

  11. Stop Tobacco in Restaurants: Fifth Grade Students STIR City Hall

    ERIC Educational Resources Information Center

    Morris, Ronald Vaughan

    2008-01-01

    This article discusses a campaign called STIR: Stop Tobacco in Restaurants, that was started by fourth and fifth grade students. The goal was to end smoking in public places, including restaurants, bowling alleys, sports bars, and pool halls. For two years they motivated their peers, coordinated an information campaign to urge kids and adults to…

  12. Hanford Waste Tank Grouping Study

    SciTech Connect

    Remund, K.M.; Simpson, B.C.

    1996-09-30

    This letter report discusses the progress and accomplishments of the Tank Grouping Study in FY96. Forty-one single-shell tanks (SSTs) were included in the FY95. In FY96, technical enhancements were also made to data transformations and tank grouping methods. The first focus of the FY96 effort was a general tank grouping study in which the 41 SSTs were grouped into classes with similar waste properties. The second FY96 focus was a demonstration of how multivariate statistical methods can be used to help resolve tank safety issues.

  13. Numerical Investigation of Effect of Stirring Blades on Mixing Efficiency of a Planetary Kneading Mixer with Non-Newtonian and Viscoplastic Materials

    NASA Astrophysics Data System (ADS)

    Yi, Pengxing; Hu, Youmin; Liu, Shiyuan

    2008-07-01

    Methods to visualize and analyze the mixing process happening in the planetary kneading mixers, which are used to mix Non-Newtonian and viscoplastic fluid, are proposed. These methods include developing three-dimensional model of the stirring blades, establishing the physical and mathematical models of the flow field in the mixing tank of the planetary kneading mixers, determining the boundary conditions of numerical simulation be virtue of rheological theory and rules, and deeply investigating the characteristics of velocity field and flow pattern of the mixing field numerically simulated by using CFD software. On the other hand, some mixing efficiency evaluating indexes for this type of mixers and their calculating methods are proposed. Based on above mentioned methods, the relationship of the geometrical parameters of stirring blades and the mixing efficiency of the planetary kneading mixers was investigated. The investigating results illustrate that preferable mixing efficiency can be achieved when the value of the helix angle, mounting central distance and mounting clearance of the stirring blades are chosen properly.

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

    NASA Technical Reports Server (NTRS)

    Hartley, Paula J.; Hartley, David E.; McCool, Alex (Technical Monitor)

    2002-01-01

    The Friction Stir Welding process developed by The Welding Institute (TWI) has found application throughout the transportation industry. This technique has proven to be a viable joining process for aluminum alloys, producing virtually defect free welds with improved mechanical properties as compared to conventional fusion welding. Lockheed Martin Space Systems - Michoud Operations has been developing this technology for application on aluminum 2219 and 2195 cryogenic tankage since 1995. This effort will come to fruition with implementation on the longitudinal welds of the External Fuel Tank (ET) of the Shuttle. To this end, sub-and full-scale demonstration programs coupled with process development and optimization have been complete. Full size ET tool has been designed, fabricated and are being installed at the Michoud Assembly Facility. Upon completion of the tooling certification and materials allowables testing, production will commence. This implementation will result in increased reliability and safety of flight for the Shuttle.

  15. 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.

  16. DEEP Study: does EQ-5D-5L measure the impacts of persistent oro-facial pain?

    PubMed

    Durham, J; Steele, J G; Breckons, M; Story, W; Vale, L

    2015-09-01

    The EQ-5D-5L is a generic quality of life (QOL) measure widely used throughout the world, which has the advantage that it allows health-state preferences to be elicited. The aim of this study was to examine whether: a) variation in the standardised reference period for EQ-5D-5L from 'today' to 'the last month' had a minimal clinically meaningful difference; (b) EQ-5D-5L had convergent validity with a multidimensional pain measure in quantifying the impacts of pain. As part of a larger study into the effectiveness and efficiency of care pathways for persistent orofacial pain (POFP) (http://research.ncl.ac.uk/deepstudy), participants with POFP (n = 100) completed two versions of the EQ-5D-5L at the same time with different reference periods ('today' vs. 'last month'). Participants also completed the first section of the West Haven-Yale Multidimensional Pain Inventory (v3) to assess convergent validity. Two-tailed nonparametric inferential statistics, intra-class correlation coefficients (ICC), and within-subject change scores were used to compare the two EQ-5D-5L versions. Convergent validity was assessed using Spearman's rho correlation coefficients. Health-state valuations were significantly different (P < 0.01), and there was good similarity between the two versions' ICC 0.86 (95% CI 0.79-0.91). The within-subject mean change was 0.03 (95% CI 0.01-0.06). For convergent validity, all relationships were significant (P < 0.05) and in the expected directions. EQ-5D-5L demonstrates sufficient convergent validity to be used with POFP, and a change in the standard reference period may be unnecessary if a multidimensional pain measure is also used.

  17. Adhesions of extracellular surface-layer associated proteins in Lactobacillus M5-L and Q8-L.

    PubMed

    Zhang, Yingchun; Xiang, Xinling; Lu, Qianhui; Zhang, Lanwei; Ma, Fang; Wang, Linlin

    2016-02-01

    Surface-layer associated proteins (SLAP) that envelop Lactobacillus paracasei ssp. paracasei M5-L and Lactobacillus casei Q8-L cell surfaces are involved in the adherence of these strain to the human intestinal cell line HT-29. To further elucidate some of the properties of these proteins, we assessed the yields and expressions of SLAP under different incubation conditions. An efficient and selective extraction of SLAP was obtained when cells of Lactobacillus were treated with 5 M LiCl at 37°C in aerobic conditions. The SLAP of Lactobacillus M5-L and Q8-L in cell extracts were visualized by SDS-PAGE and identified by Western blotting with sulfo-N-hydroxysuccinimide-biotin-labeled HT-29 cells as adhesion proteins. Atomic force microscopy contact imaging revealed that Lactobacillus strains M5-L and Q8-L normally display a smooth, homogeneous surface, whereas the surfaces of M5-L and Q8-L treated with 5 M LiCl were rough and more heterogeneous. Analysis of adhesion forces revealed that the initial adhesion forces of 1.41 and 1.28 nN obtained for normal Lactobacillus M5-L and Q8-L strains, respectively, decreased to 0.70 and 0.48 nN, respectively, following 5 M LiCl treatment. Finally, the dominant 45-kDa protein bands of Lactobacillus Q8-L and Lactobacillus M5-L were identified as elongation factor Tu and surface antigen, respectively, by liquid chromatography-tandem mass spectrometry.

  18. Adhesions of extracellular surface-layer associated proteins in Lactobacillus M5-L and Q8-L.

    PubMed

    Zhang, Yingchun; Xiang, Xinling; Lu, Qianhui; Zhang, Lanwei; Ma, Fang; Wang, Linlin

    2016-02-01

    Surface-layer associated proteins (SLAP) that envelop Lactobacillus paracasei ssp. paracasei M5-L and Lactobacillus casei Q8-L cell surfaces are involved in the adherence of these strain to the human intestinal cell line HT-29. To further elucidate some of the properties of these proteins, we assessed the yields and expressions of SLAP under different incubation conditions. An efficient and selective extraction of SLAP was obtained when cells of Lactobacillus were treated with 5 M LiCl at 37°C in aerobic conditions. The SLAP of Lactobacillus M5-L and Q8-L in cell extracts were visualized by SDS-PAGE and identified by Western blotting with sulfo-N-hydroxysuccinimide-biotin-labeled HT-29 cells as adhesion proteins. Atomic force microscopy contact imaging revealed that Lactobacillus strains M5-L and Q8-L normally display a smooth, homogeneous surface, whereas the surfaces of M5-L and Q8-L treated with 5 M LiCl were rough and more heterogeneous. Analysis of adhesion forces revealed that the initial adhesion forces of 1.41 and 1.28 nN obtained for normal Lactobacillus M5-L and Q8-L strains, respectively, decreased to 0.70 and 0.48 nN, respectively, following 5 M LiCl treatment. Finally, the dominant 45-kDa protein bands of Lactobacillus Q8-L and Lactobacillus M5-L were identified as elongation factor Tu and surface antigen, respectively, by liquid chromatography-tandem mass spectrometry. PMID:26709174

  19. DEEP Study: does EQ-5D-5L measure the impacts of persistent oro-facial pain?

    PubMed

    Durham, J; Steele, J G; Breckons, M; Story, W; Vale, L

    2015-09-01

    The EQ-5D-5L is a generic quality of life (QOL) measure widely used throughout the world, which has the advantage that it allows health-state preferences to be elicited. The aim of this study was to examine whether: a) variation in the standardised reference period for EQ-5D-5L from 'today' to 'the last month' had a minimal clinically meaningful difference; (b) EQ-5D-5L had convergent validity with a multidimensional pain measure in quantifying the impacts of pain. As part of a larger study into the effectiveness and efficiency of care pathways for persistent orofacial pain (POFP) (http://research.ncl.ac.uk/deepstudy), participants with POFP (n = 100) completed two versions of the EQ-5D-5L at the same time with different reference periods ('today' vs. 'last month'). Participants also completed the first section of the West Haven-Yale Multidimensional Pain Inventory (v3) to assess convergent validity. Two-tailed nonparametric inferential statistics, intra-class correlation coefficients (ICC), and within-subject change scores were used to compare the two EQ-5D-5L versions. Convergent validity was assessed using Spearman's rho correlation coefficients. Health-state valuations were significantly different (P < 0.01), and there was good similarity between the two versions' ICC 0.86 (95% CI 0.79-0.91). The within-subject mean change was 0.03 (95% CI 0.01-0.06). For convergent validity, all relationships were significant (P < 0.05) and in the expected directions. EQ-5D-5L demonstrates sufficient convergent validity to be used with POFP, and a change in the standard reference period may be unnecessary if a multidimensional pain measure is also used. PMID:25818477

  20. Suspension culture of human pluripotent stem cells in controlled, stirred bioreactors.

    PubMed

    Olmer, Ruth; Lange, Andreas; Selzer, Sebastian; Kasper, Cornelia; Haverich, Axel; Martin, Ulrich; Zweigerdt, Robert

    2012-10-01

    Therapeutic and industrial applications of pluripotent stem cells and their derivatives require large cell quantities generated in defined conditions. To this end, we have translated single cell-inoculated suspension cultures of human pluripotent stem cells (hPSCs; including human induced pluripotent stem cells [hiPS] and human embryonic stem cells [hESC]) to stirred tank bioreactors. These systems that are widely used in biopharmaceutical industry allow straightforward scale up and detailed online monitoring of key process parameters. To ensure minimum medium consumption, but in parallel functional integration of all probes mandatory for process monitoring, that is, for pO₂ and pH, experiments were performed in 100 mL culture volume in a "mini reactor platform" consisting of four independently controlled vessels. By establishing defined parameters for tightly controlled cell inoculation and aggregate formation up to 2×10⁸ hiPSCs/100 mL were generated in a single process run in 7 days. Expression of pluripotency markers and ability of cells to differentiate into derivates of all three germ layers in vitro was maintained, underlining practical utility of this new process. The presented data provide key steps toward scalable mass expansion of human iPS and ES cells thereby enabling translation of stem cell research to (pre)clinical application in relevant large animal models and valuable in vitro assays for drug development and validation as well.

  1. Simulated Service and Stress Corrosion Cracking Testing for Friction Stir Welded Spun Formed Domes

    NASA Technical Reports Server (NTRS)

    Stewart, Thomas J.; Torres, Pablo D.; Caratus, Andrei A.; Curreri, Peter A.

    2010-01-01

    Simulated service testing (SST) development was required to help qualify a new 2195 aluminum lithium (Al-Li) alloy spin forming dome fabrication process for the National Aeronautics and Space Administration (NASA) Exploration Development Technology Program. The application for the technology is to produce high strength low weight tank components for NASA s next generation launch vehicles. Since plate material is not currently manufactured large enough to fabricate these domes, two plates are joined by means of friction stir welding. The plates are then pre-contour machined to near final thicknesses allowing for a thicker weld land and anticipating the level of stretch induced by the spin forming process. The welded plates are then placed in a spin forming tool and hot stretched using a trace method producing incremental contours. Finally the dome receives a room temperature contour stretch to final dimensions, heat treatment, quenching, and artificial aging to emulate a T-8 condition of temper. Stress corrosion cracking (SCC) tests were also performed by alternate immersion in a sodium chloride (NaCl) solution using the typical double beam assembly and with 4-point loaded specimens and use of bent-beam stress-corrosion test specimens under alternate immersion conditions. In addition, experiments were conducted to determine the threshold stress intensity factor for SCC (K(sub ISCC)) which to our knowledge has not been determined previously for Al-Li 2195 alloy. The successful simulated service and stress corrosion testing helped to provide confidence to continue to Ares 1 scale dome fabrication

  2. Suspension Culture of Human Pluripotent Stem Cells in Controlled, Stirred Bioreactors

    PubMed Central

    Olmer, Ruth; Lange, Andreas; Selzer, Sebastian; Kasper, Cornelia; Haverich, Axel

    2012-01-01

    Therapeutic and industrial applications of pluripotent stem cells and their derivatives require large cell quantities generated in defined conditions. To this end, we have translated single cell-inoculated suspension cultures of human pluripotent stem cells (hPSCs; including human induced pluripotent stem cells [hiPS] and human embryonic stem cells [hESC]) to stirred tank bioreactors. These systems that are widely used in biopharmaceutical industry allow straightforward scale up and detailed online monitoring of key process parameters. To ensure minimum medium consumption, but in parallel functional integration of all probes mandatory for process monitoring, that is, for pO2 and pH, experiments were performed in 100 mL culture volume in a “mini reactor platform” consisting of four independently controlled vessels. By establishing defined parameters for tightly controlled cell inoculation and aggregate formation up to 2×108 hiPSCs/100 mL were generated in a single process run in 7 days. Expression of pluripotency markers and ability of cells to differentiate into derivates of all three germ layers in vitro was maintained, underlining practical utility of this new process. The presented data provide key steps toward scalable mass expansion of human iPS and ES cells thereby enabling translation of stem cell research to (pre)clinical application in relevant large animal models and valuable in vitro assays for drug development and validation as well. PMID:22519745

  3. Auto-Adjustable Tool for Self-Reacting and Conventional Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Carter, Robert W. (Inventor)

    2002-01-01

    A friction stir welding dcvice that is configured to perform convention friction stir welding as well as self-reacting friction stir welding is described. A pin passes hrough an upper shoulder and can selectively attach 10 and detach from a lower shoulder in a preferred embodiment. A controller maintains thc discrete position of, and/or force applied by, the upper and lower shoulders during self-reacting friction stir welding, or maintains the pin at a desired depth and/or applied force during conventional friction stir welding.

  4. TankSIM: A Cryogenic Tank Performance Prediction Program

    NASA Technical Reports Server (NTRS)

    Bolshinskiy, L. G.; Hedayat, A.; Hastings, L. J.; Moder, J. P.; Schnell, A. R.; Sutherlin, S. G.

    2015-01-01

    Accurate prediction of the thermodynamic state of the cryogenic propellants in launch vehicle tanks is necessary for mission planning and successful execution. Cryogenic propellant storage and transfer in space environments requires that tank pressure be controlled. The pressure rise rate is determined by the complex interaction of external heat leak, fluid temperature stratification, and interfacial heat and mass transfer. If the required storage duration of a space mission is longer than the period in which the tank pressure reaches its allowable maximum, an appropriate pressure control method must be applied. Therefore, predictions of the pressurization rate and performance of pressure control techniques in cryogenic tanks are required for development of cryogenic fluid long-duration storage technology and planning of future space exploration missions. This paper describes an analytical tool, Tank System Integrated Model (TankSIM), which can be used for modeling pressure control and predicting the behavior of cryogenic propellant for long-term storage for future space missions. It is written in the FORTRAN 90 language and can be compiled with any Visual FORTRAN compiler. A thermodynamic vent system (TVS) is used to achieve tank pressure control. Utilizing TankSIM, the following processes can be modeled: tank self-pressurization, boiloff, ullage venting, and mixing. Details of the TankSIM program and comparisons of its predictions with test data for liquid hydrogen and liquid methane will be presented in the final paper.

  5. Tank 241-AP-106 tank characterization plan: Revision 1

    SciTech Connect

    Valenzuela, B.D.

    1994-11-17

    Tank 241-AP-106 (AP-106) is a candidate feed tank which is expected to be processed at the 242-A Evaporator. Three issues related to the overall concern of the evaporator must be evaluated: compatibility of the candidate waste with respect to feed tank, slurry tank, and evaporator requirements; safety parameters of the candidate waste tank to avoid a facility condition which is outside the safety boundaries; and compliance of the waste as dictated by regulations from various government and environmental agencies. The characterization efforts of this Tank Characterization Plan are focused on the resolution of the issues above. To evaluate the potential for waste incompatibility with the feed tank, slurry tank, and evaporator, as well as relevant safety issues, analyses will be performed on the grab samples obtained from tank AP-106. These analyses are discussed in Section 4.0. Once the characterization of tank AP-106 has been performed, the waste compatibility and safety assessment shall be conducted. This effort is discussed elsewhere.

  6. Tank characterization report for Single-Shell Tank B-111

    SciTech Connect

    Remund, K.M.; Tingey, J.M.; Heasler, P.G.; Toth, J.J.; Ryan, F.M.; Hartley, S.A.; Simpson, D.B.; Simpson, B.C.

    1994-09-01

    Tank 241-B-111 (hereafter referred to as B-111) is a 2,006,300 liter (530,000 gallon) single-shell waste tank located in the 200 East B tank farm at Hanford. Two cores were taken from this tank in 1991 and analysis of the cores was conducted by Battelle`s 325-A Laboratory in 1993. Characterization of the waste in this tank is being done to support Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-44-05. Tank B-111 was constructed in 1943 and put into service in 1945; it is the second tank in a cascade system with Tanks B-110 and B-112. During its process history, B-111 received mostly second-decontamination-cycle waste and fission products waste via the cascade from Tank B-110. This tank was retired from service in 1976, and in 1978 the tank was assumed to have leaked 30,300 liters (8,000 gallons). The tank was interim stabilized and interim isolated in 1985. The tank presently contains approximately 893,400 liters (236,000 gallons) of sludge-like waste and approximately 3,800 liters (1,000 gallons) of supernate. 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 1991. An extensive set of analytical measurements was performed on the core composites. The major constituents (> 0.5 wt%) measured in the waste are water, sodium, nitrate, phosphate, nitrite, bismuth, iron, sulfate and silicon, ordered from largest concentration to the smallest. The concentrations and inventories of these and other constituents are given. Since Tanks B-110 and B-111 have similar process histories, their sampling results were compared. The results of the chemical analyses have been compared to the dangerous waste codes in the Washington Dangerous Waste Regulations (WAC 173-303). This assessment was conducted by comparing tank analyses against dangerous waste characteristics `D` waste codes; and against state waste codes.

  7. Tank characterization data report: Tank 241-C-112

    SciTech Connect

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

    1993-09-01

    Tank 241-C-112 is a Hanford Site Ferrocyanide Watch List tank that was most recently sampled in March 1992. Analyses of materials obtained from tank 241-C-112 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. Analysis of core samples obtained from tank 241-C-112 strongly indicates that the fuel concentration in the tank waste will not support a propagating exothermic reaction. Analysis of the process history of the tank as well as studies of simulants provided valuable information about the physical and chemical condition of the waste. This information, in combination with the analysis of the tank waste, sup ports the conclusion that an exothermic reaction in tank 241-C-112 is not plausible. Therefore, the contents of tank 241-C-112 present no imminent threat to the workers at the Hanford Site, the public, or the environment from its forrocyanide inventory. Because an exothermic reaction is not credible, the consequences of this accident scenario, as promulgated by the General Accounting Office, are not applicable.

  8. Tank Characterization Report for Double Shell Tank (DST) 241-AN-107

    SciTech Connect

    ADAMS, M.R.

    2000-03-23

    This report 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.

  9. Robotic Manufacturing of 5.5 Meter Cryogenic Fuel Tank Dome Assemblies for the NASA Ares I Rocket

    NASA Technical Reports Server (NTRS)

    Jones, Ronald E.

    2012-01-01

    The Ares I rocket is the first launch vehicle scheduled for manufacture under the National Aeronautic and Space Administration's (NASA's) Constellation program. A series of full-scale Ares I development articles have been constructed on the Robotic Weld Tool at the NASA George C. Marshall Space Flight Center in Huntsville, Alabama. The Robotic Weld Tool is a 100 ton, 7-axis, robotic manufacturing system capable of machining and friction stir welding large-scale space hardware. This presentation will focus on the friction stir welding of 5.5m diameter cryogenic fuel tank components; specifically, the liquid hydrogen forward dome (LH2 MDA), the common bulkhead manufacturing development articles (CBMDA) and the thermal protection system demonstration dome (TPS Dome). The LH2 MDA was the first full-scale, flight-like Ares I hardware produced under the Constellation Program. It is a 5.5m diameter elliptical dome assembly consisting of eight gore panels, a y-ring stiffener and a manhole fitting. All components are made from aluminumlithium alloy 2195. Conventional and self-reacting friction stir welding was used on this article. An overview of the manufacturing processes will be discussed. The LH2 MDA is the first known fully friction stir welded dome ever produced. The completion of four Common Bulkhead Manufacturing Development Articles (CBMDA) and the TPS Dome will also be highlighted. Each CBMDA and the TPS Dome consists of a 5.5m diameter spun-formed dome friction stir welded to a y-ring stiffener. The domes and y-rings are made of aluminum 2014 and 2219 respectively. The TPS Dome has an additional aluminum alloy 2195 barrel section welded to the y-ring. Manufacturing solutions will be discussed including "fixtureless" welding with self reacting friction stir welding.

  10. 27 CFR 19.183 - Scale tanks.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Tank Requirements § 19.183 Scale tanks. (a) Except as otherwise provided in paragraph (b) of this... quickly and accurately determined. (b) The requirement to mount tanks on scales does not apply to tanks... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Scale tanks....

  11. 27 CFR 19.183 - Scale tanks.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Tank Requirements § 19.183 Scale tanks. (a) Except as otherwise provided in paragraph (b) of this... quickly and accurately determined. (b) The requirement to mount tanks on scales does not apply to tanks... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Scale tanks....

  12. 27 CFR 19.183 - Scale tanks.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Tank Requirements § 19.183 Scale tanks. (a) Except as otherwise provided in paragraph (b) of this... quickly and accurately determined. (b) The requirement to mount tanks on scales does not apply to tanks... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Scale tanks....

  13. 27 CFR 19.183 - Scale tanks.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Tank Requirements § 19.183 Scale tanks. (a) Except as otherwise provided in paragraph (b) of this... quickly and accurately determined. (b) The requirement to mount tanks on scales does not apply to tanks... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Scale tanks....

  14. 46 CFR 154.439 - Tank design.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Tank design. 154.439 Section 154.439 Shipping COAST... Tank Type A § 154.439 Tank design. An independent tank type A must meet the deep tank standard of the American Bureau of Shipping published in “Rules for Building and Classing Steel Vessels”, 1981, and...

  15. 46 CFR 154.420 - Tank design.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Tank design. 154.420 Section 154.420 Shipping COAST... SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Integral Tanks § 154.420 Tank design. (a) The structure of an integral tank must meet the deep tank scantling...

  16. 46 CFR 154.439 - Tank design.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Tank design. 154.439 Section 154.439 Shipping COAST... Tank Type A § 154.439 Tank design. An independent tank type A must meet the deep tank standard of the American Bureau of Shipping published in “Rules for Building and Classing Steel Vessels”, 1981, and...

  17. 46 CFR 154.439 - Tank design.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Tank design. 154.439 Section 154.439 Shipping COAST... Tank Type A § 154.439 Tank design. An independent tank type A must meet the deep tank standard of the American Bureau of Shipping published in “Rules for Building and Classing Steel Vessels”, 1981, and...

  18. 46 CFR 154.420 - Tank design.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Tank design. 154.420 Section 154.420 Shipping COAST... SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Integral Tanks § 154.420 Tank design. (a) The structure of an integral tank must meet the deep tank scantling...

  19. 46 CFR 154.420 - Tank design.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Tank design. 154.420 Section 154.420 Shipping COAST... SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Integral Tanks § 154.420 Tank design. (a) The structure of an integral tank must meet the deep tank scantling...

  20. 46 CFR 154.420 - Tank design.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Tank design. 154.420 Section 154.420 Shipping COAST... SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Integral Tanks § 154.420 Tank design. (a) The structure of an integral tank must meet the deep tank scantling...

  1. 46 CFR 154.439 - Tank design.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Tank design. 154.439 Section 154.439 Shipping COAST... SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type A § 154.439 Tank design. An independent tank type A must meet the deep tank standard of...

  2. 46 CFR 154.420 - Tank design.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Tank design. 154.420 Section 154.420 Shipping COAST... SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Integral Tanks § 154.420 Tank design. (a) The structure of an integral tank must meet the deep tank scantling...

  3. 46 CFR 154.439 - Tank design.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Tank design. 154.439 Section 154.439 Shipping COAST... SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Independent Tank Type A § 154.439 Tank design. An independent tank type A must meet the deep tank standard of...

  4. 49 CFR 238.423 - Fuel tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Fuel tanks. 238.423 Section 238.423 Transportation....423 Fuel tanks. (a) External fuel tanks. Each type of external fuel tank must be approved by FRA's Associate Administrator for Safety upon a showing that the fuel tank provides a level of safety at...

  5. 49 CFR 238.423 - Fuel tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Fuel tanks. 238.423 Section 238.423 Transportation....423 Fuel tanks. (a) External fuel tanks. Each type of external fuel tank must be approved by FRA's Associate Administrator for Safety upon a showing that the fuel tank provides a level of safety at...

  6. 49 CFR 238.423 - Fuel tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Fuel tanks. 238.423 Section 238.423 Transportation....423 Fuel tanks. (a) External fuel tanks. Each type of external fuel tank must be approved by FRA's Associate Administrator for Safety upon a showing that the fuel tank provides a level of safety at...

  7. 49 CFR 238.423 - Fuel tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Fuel tanks. 238.423 Section 238.423 Transportation....423 Fuel tanks. (a) External fuel tanks. Each type of external fuel tank must be approved by FRA's Associate Administrator for Safety upon a showing that the fuel tank provides a level of safety at...

  8. 14 CFR 23.1013 - Oil tanks.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Oil tanks. 23.1013 Section 23.1013... tanks. (a) Installation. Each oil tank must be installed to— (1) Meet the requirements of § 23.967 (a...) Expansion space. Oil tank expansion space must be provided so that— (1) Each oil tank used with...

  9. 27 CFR 25.35 - Tanks.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Tanks. 25.35 Section 25.35... TREASURY LIQUORS BEER Construction and Equipment Equipment § 25.35 Tanks. Each stationary tank, vat, cask... contents of tanks or containers in lieu of providing each tank or container with a measuring device....

  10. 49 CFR 230.116 - Oil tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Oil tanks. 230.116 Section 230.116 Transportation... Locomotive Tanks § 230.116 Oil tanks. The oil tanks on oil burning steam locomotives shall be maintained free... adjacent to the fuel supply tank or in another safe location; (b) Closes automatically when tripped...

  11. 49 CFR 238.423 - Fuel tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Fuel tanks. 238.423 Section 238.423 Transportation....423 Fuel tanks. (a) External fuel tanks. Each type of external fuel tank must be approved by FRA's Associate Administrator for Safety upon a showing that the fuel tank provides a level of safety at...

  12. 46 CFR 153.266 - Tank linings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Tank linings. 153.266 Section 153.266 Shipping COAST... LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Tanks § 153.266 Tank linings. A tank lining must be: (a) At least as elastic as the tank material; and (b) Applied...

  13. Effect of friction stir welding parameters on defect formation

    NASA Astrophysics Data System (ADS)

    Tarasov, S. Yu.; Rubtsov, V. E.; Eliseev, A. A.; Kolubaev, E. A.; Filippov, A. V.; Ivanov, A. N.

    2015-10-01

    Friction stir welding is a perspective method for manufacturing automotive parts, aviation and space technology. One of the major problems is the formation of welding defects and weld around the welding zone. The formation of defect is the main reason failure of the joint. A possible way to obtain defect-free welded joints is the selection of the correct welding parameters. Experimental results describing the effect of friction stir welding process parameters on the defects of welded joints on aluminum alloy AMg5M have been shown. The weld joint defects have been characterized using the non-destructive radioscopic and ultrasound phase array methods. It was shown how the type and size of defects determine the welded joint strength.

  14. FRICTION STIR LAP WELDING OF ALUMINUM - POLYMER USING SCRIBE TECHNOLOGY

    SciTech Connect

    Upadhyay, Piyush; Hovanski, Yuri; Fifield, Leonard S.; Simmons, Kevin L.

    2015-02-16

    Friction Stir Scribe (FSS) technology is a relatively new variant of Friction Stir Welding (FSW) which enables lap joining of dissimilar material with very different melting points and different high temperature flow behaviors. The cutter scribe attached at the tip of FSW tool pin effectively cuts the high melting point material such that a mechanically interlocking feature is created between the dissimilar materials. The geometric shape of this interlocking feature determines the shear strength attained by the lap joint. This work presents first use of scribe technology in joining polymers to aluminum alloy. Details of the several runs of scribe welding performed in lap joining of ~3.175mm thick polymers including HDPE, filled and unfilled Nylon 66 to 2mm thick AA5182 are presented. The effect of scribe geometry and length on weld interlocking features is presented along with lap shear strength evaluations.

  15. Electromagnetic stirring with alternating current during electroslag remelting

    NASA Astrophysics Data System (ADS)

    Mitchell, Alec; Hernandez-Morales, Bernardo

    1990-08-01

    An alternating current (AC)-operated electromagnetic stirring (EMS) device, using line frequency, was designed and built to operate on a laboratory electroslag remelting (ESR) furnace for 150-mm-diameter ingots. Laboratory-scale experiments were conducted employing both 4340 alloy steel and INCONEL 718 alloy as electrode material. The initiation of stirring is accompanied by a thin strip of segregated material and favors the formation of spot segregation. Changes produced in the fluid flow conditions in the liquid pool ahead of the solidification front result in a transition from a highly directional columnar to an unoriented, branched structure. Except for small pockets of segregated liquid, the flow of molten metal does not penetrate into the mushy zone. Both electrode material and molten metal pool shape play an important role on the extent of promoting an equiaxed structure.

  16. Heat Treatment of Friction-Stir-Welded 7050 Aluminum Plates

    NASA Technical Reports Server (NTRS)

    Petter, George E.; Figert, John D.; Rybicki, Daniel J.; Burns, Timothy

    2006-01-01

    A method of heat treatment has been developed to reverse some of the deleterious effects of friction stir welding of plates of aluminum alloy 7050. This alloy is considered unweldable by arc and high-energy-density beam fusion welding processes. The alloy can be friction stir welded, but as-welded workpieces exhibit low ductility, low tensile and yield strengths, and low resistance to stress corrosion cracking. Heat treatment according to the present method increases tensile and yield strengths, and minimizes or eliminates stress corrosion cracking. It also increases ductility. This method of heat treatment is a superior alternative to a specification-required heat treatment that caused the formation of large columnar grains, which are undesired. Workpieces subjected to the prior heat treatment exhibited elongations <2 percent, and standard three-point bend specimens shattered. The development of the present heat treatment method was guided partly by the principles that (1) by minimizing grain sizes and relieving deformation stresses, one can minimize or eliminate stress corrosion cracking and (2) the key to maximizing strength and eliminating residual stresses is to perform post-weld solution heating for as long a time as possible while incurring little or no development of large columnar grains in friction stir weld nuggets. It is necessary to perform some of the solution heat treatment (to soften the alloy and improve machine welding parameters) before welding. The following is an example of thickness- dependent pre- and post-weld heat treatments according to the present method: For plates 0.270 in. (approx.6.86 mm) thick milled from plates 4.5 in. (114.3 mm) thick, perform pre-weld solution heating at 890 F (477 C) for 1 hour, then cool in air. After friction stir welding, perform solution heating for 10 minutes, quench, hold at room temperature for 96 hours, then age at 250 F (121 C) for 5 hours followed by 325 F (163 C) for 27 hours.

  17. Derivation of iPSCs in stirred suspension bioreactors.

    PubMed

    Shafa, Mehdi; Day, Brad; Yamashita, Akihiro; Meng, Guoliang; Liu, Shiying; Krawetz, Roman; Rancourt, Derrick E

    2012-04-08

    Induced pluripotent stem cells (iPSCs) are typically derived in adherent culture. Here we report fast and efficient derivation of mouse iPSCs in stirred suspension bioreactors, with and without the use of c-Myc. Suspension-reprogrammed cells expressed pluripotency markers, showed multilineage differentiation in vitro and in vivo, and contributed to the germline in chimeric mice. Suspension reprogramming has the potential to accelerate and standardize iPSC research.

  18. 49 CFR 179.100 - General specifications applicable to pressure tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... car tanks. 179.100 Section 179.100 Transportation Other Regulations Relating to Transportation...) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100 General specifications applicable to pressure tank car tanks....

  19. 27 CFR 27.174 - Tank cars and tank trucks to be sealed.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Tank cars and tank trucks... Tank cars and tank trucks to be sealed. Where a shipment of distilled spirits from customs custody to the distilled spirits plant is made in a tank car or tank truck, all openings affording access to...

  20. 49 CFR 179.102 - Special commodity requirements for pressure tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... car tanks. 179.102 Section 179.102 Transportation Other Regulations Relating to Transportation...) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.102 Special commodity requirements for pressure tank car tanks. (a) In addition to §§ 179.100...

  1. 49 CFR 179.100 - General specifications applicable to pressure tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... car tanks. 179.100 Section 179.100 Transportation Other Regulations Relating to Transportation...) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100 General specifications applicable to pressure tank car tanks....

  2. 49 CFR 179.102 - Special commodity requirements for pressure tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... car tanks. 179.102 Section 179.102 Transportation Other Regulations Relating to Transportation...) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.102 Special commodity requirements for pressure tank car tanks. (a) In addition to §§ 179.100...

  3. 49 CFR 179.103 - Special requirements for class 114A * * * tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Special requirements for class 114A * * * tank car...) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.103 Special requirements for class 114A * * * tank car tanks. (a) In addition to the...

  4. 49 CFR 179.101 - Individual specification requirements applicable to pressure tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... to pressure tank car tanks. 179.101 Section 179.101 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.101 Individual specification requirements applicable to pressure tank...

  5. 27 CFR 27.174 - Tank cars and tank trucks to be sealed.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Tank cars and tank trucks... Tank cars and tank trucks to be sealed. Where a shipment of distilled spirits from customs custody to the distilled spirits plant is made in a tank car or tank truck, all openings affording access to...

  6. 49 CFR 179.103 - Special requirements for class 114A * * * tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Special requirements for class 114A * * * tank car...) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.103 Special requirements for class 114A * * * tank car tanks. (a) In addition to the...

  7. 49 CFR 179.101 - Individual specification requirements applicable to pressure tank car tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... to pressure tank car tanks. 179.101 Section 179.101 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.101 Individual specification requirements applicable to pressure tank...

  8. 49 CFR 179.101 - Individual specification requirements applicable to pressure tank car tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... to pressure tank car tanks. 179.101 Section 179.101 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.101 Individual specification requirements applicable to pressure tank...

  9. 49 CFR 179.100 - General specifications applicable to pressure tank car tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... car tanks. 179.100 Section 179.100 Transportation Other Regulations Relating to Transportation...) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100 General specifications applicable to pressure tank car tanks....

  10. 33 CFR 157.208 - Dedicated Clean Ballast Tanks Operations Manual for foreign tank vessels: Submission.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Dedicated Clean Ballast Tanks... MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Dedicated Clean Ballast Tanks on Tank Vessels General § 157.208 Dedicated Clean Ballast Tanks Operations Manual for foreign tank...

  11. 33 CFR 157.208 - Dedicated Clean Ballast Tanks Operations Manual for foreign tank vessels: Submission.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Dedicated Clean Ballast Tanks... MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Dedicated Clean Ballast Tanks on Tank Vessels General § 157.208 Dedicated Clean Ballast Tanks Operations Manual for foreign tank...

  12. 33 CFR 157.208 - Dedicated Clean Ballast Tanks Operations Manual for foreign tank vessels: Submission.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Dedicated Clean Ballast Tanks... MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Dedicated Clean Ballast Tanks on Tank Vessels General § 157.208 Dedicated Clean Ballast Tanks Operations Manual for foreign tank...

  13. 33 CFR 157.208 - Dedicated Clean Ballast Tanks Operations Manual for foreign tank vessels: Submission.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Dedicated Clean Ballast Tanks... MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Dedicated Clean Ballast Tanks on Tank Vessels General § 157.208 Dedicated Clean Ballast Tanks Operations Manual for foreign tank...

  14. 49 CFR 179.103 - Special requirements for class 114A * * * tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Special requirements for class 114A * * * tank car... SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.103 Special requirements for class 114A * * * tank car tanks. (a) In addition to the...

  15. 49 CFR 179.102 - Special commodity requirements for pressure tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... car tanks. 179.102 Section 179.102 Transportation Other Regulations Relating to Transportation... REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.102 Special commodity requirements for pressure tank car tanks. (a) In addition...

  16. 49 CFR 179.100 - General specifications applicable to pressure tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... car tanks. 179.100 Section 179.100 Transportation Other Regulations Relating to Transportation... REGULATIONS SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100 General specifications applicable to pressure tank car tanks....

  17. 33 CFR 157.208 - Dedicated Clean Ballast Tanks Operations Manual for foreign tank vessels: Submission.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Dedicated Clean Ballast Tanks... MARINE ENVIRONMENT RELATING TO TANK VESSELS CARRYING OIL IN BULK Dedicated Clean Ballast Tanks on Tank Vessels General § 157.208 Dedicated Clean Ballast Tanks Operations Manual for foreign tank...

  18. 27 CFR 27.174 - Tank cars and tank trucks to be sealed.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Tank cars and tank trucks... Tank cars and tank trucks to be sealed. Where a shipment of distilled spirits from customs custody to the distilled spirits plant is made in a tank car or tank truck, all openings affording access to...

  19. 49 CFR 179.103 - Special requirements for class 114A * * * tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Special requirements for class 114A * * * tank car...) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.103 Special requirements for class 114A * * * tank car tanks. (a) In addition to the...

  20. 49 CFR 179.100 - General specifications applicable to pressure tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... car tanks. 179.100 Section 179.100 Transportation Other Regulations Relating to Transportation...) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100 General specifications applicable to pressure tank car tanks....

  1. 49 CFR 179.101 - Individual specification requirements applicable to pressure tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... to pressure tank car tanks. 179.101 Section 179.101 Transportation Other Regulations Relating to... (CONTINUED) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.101 Individual specification requirements applicable to pressure tank...

  2. 49 CFR 179.102 - Special commodity requirements for pressure tank car tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... car tanks. 179.102 Section 179.102 Transportation Other Regulations Relating to Transportation...) SPECIFICATIONS FOR TANK CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.102 Special commodity requirements for pressure tank car tanks. (a) In addition to §§ 179.100...

  3. 46 CFR 153.250 - Double-bottom and deep tanks as cargo tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Double-bottom and deep tanks as cargo tanks. 153.250... Equipment Cargo Tanks § 153.250 Double-bottom and deep tanks as cargo tanks. Except in those cases in which Commandant (CG-ENG) specifically approves another arrangement, such as a double-bottom or deep tank as...

  4. 46 CFR 153.250 - Double-bottom and deep tanks as cargo tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Double-bottom and deep tanks as cargo tanks. 153.250... Equipment Cargo Tanks § 153.250 Double-bottom and deep tanks as cargo tanks. Except in those cases in which Commandant (CG-522) specifically approves another arrangement, such as a double-bottom or deep tank as...

  5. 46 CFR 153.250 - Double-bottom and deep tanks as cargo tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Double-bottom and deep tanks as cargo tanks. 153.250... Equipment Cargo Tanks § 153.250 Double-bottom and deep tanks as cargo tanks. Except in those cases in which Commandant (CG-ENG) specifically approves another arrangement, such as a double-bottom or deep tank as...

  6. 46 CFR 153.250 - Double-bottom and deep tanks as cargo tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Double-bottom and deep tanks as cargo tanks. 153.250... Equipment Cargo Tanks § 153.250 Double-bottom and deep tanks as cargo tanks. Except in those cases in which Commandant (CG-ENG) specifically approves another arrangement, such as a double-bottom or deep tank as...

  7. 46 CFR 153.250 - Double-bottom and deep tanks as cargo tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Double-bottom and deep tanks as cargo tanks. 153.250... Equipment Cargo Tanks § 153.250 Double-bottom and deep tanks as cargo tanks. Except in those cases in which Commandant (CG-522) specifically approves another arrangement, such as a double-bottom or deep tank as...

  8. Recent Developments in Friction Stir Welding of Al-alloys

    NASA Astrophysics Data System (ADS)

    Çam, Gürel; Mistikoglu, Selcuk

    2014-06-01

    The diversity and never-ending desire for a better life standard result in a continuous development of the existing manufacturing technologies. In line with these developments in the existing production technologies the demand for more complex products increases, which also stimulates new approaches in production routes of such products, e.g., novel welding procedures. For instance, the friction stir welding (FSW) technology, developed for joining difficult-to-weld Al-alloys, has been implemented by industry in manufacturing of several products. There are also numerous attempts to apply this method to other materials beyond Al-alloys. However, the process has not yet been implemented by industry for joining these materials with the exception of some limited applications. The microstructures and mechanical properties of friction stir welded Al-alloys existing in the open literature will be discussed in detail in this review. The correlations between weld parameters used during FSW and the microstructures evolved in the weld region and thus mechanical properties of the joints produced will be highlighted. However, the modeling studies, material flow, texture formation and developments in tool design are out of the scope of this work as well as the other variants of this technology, such as friction stir spot welding (FSSW).

  9. Continuously-stirred anaerobic digester to convert organic wastes into biogas: system setup and basic operation.

    PubMed

    Usack, Joseph G; Spirito, Catherine M; Angenent, Largus T

    2012-01-01

    Anaerobic digestion (AD) is a bioprocess that is commonly used to convert complex organic wastes into a useful biogas with methane as the energy carrier. Increasingly, AD is being used in industrial, agricultural, and municipal waste(water) treatment applications. The use of AD technology allows plant operators to reduce waste disposal costs and offset energy utility expenses. In addition to treating organic wastes, energy crops are being converted into the energy carrier methane. As the application of AD technology broadens for the treatment of new substrates and co-substrate mixtures, so does the demand for a reliable testing methodology at the pilot- and laboratory-scale. Anaerobic digestion systems have a variety of configurations, including the continuously stirred tank reactor (CSTR), plug flow (PF), and anaerobic sequencing batch reactor (ASBR) configurations. The CSTR is frequently used in research due to its simplicity in design and operation, but also for its advantages in experimentation. Compared to other configurations, the CSTR provides greater uniformity of system parameters, such as temperature, mixing, chemical concentration, and substrate concentration. Ultimately, when designing a full-scale reactor, the optimum reactor configuration will depend on the character of a given substrate among many other nontechnical considerations. However, all configurations share fundamental design features and operating parameters that render the CSTR appropriate for most preliminary assessments. If researchers and engineers use an influent stream with relatively high concentrations of solids, then lab-scale bioreactor configurations cannot be fed continuously due to plugging problems of lab-scale pumps with solids or settling of solids in tubing. For that scenario with continuous mixing requirements, lab-scale bioreactors are fed periodically and we refer to such configurations as continuously stirred anaerobic digesters (CSADs). This article presents a general

  10. Continuously-stirred anaerobic digester to convert organic wastes into biogas: system setup and basic operation.

    PubMed

    Usack, Joseph G; Spirito, Catherine M; Angenent, Largus T

    2012-01-01

    Anaerobic digestion (AD) is a bioprocess that is commonly used to convert complex organic wastes into a useful biogas with methane as the energy carrier. Increasingly, AD is being used in industrial, agricultural, and municipal waste(water) treatment applications. The use of AD technology allows plant operators to reduce waste disposal costs and offset energy utility expenses. In addition to treating organic wastes, energy crops are being converted into the energy carrier methane. As the application of AD technology broadens for the treatment of new substrates and co-substrate mixtures, so does the demand for a reliable testing methodology at the pilot- and laboratory-scale. Anaerobic digestion systems have a variety of configurations, including the continuously stirred tank reactor (CSTR), plug flow (PF), and anaerobic sequencing batch reactor (ASBR) configurations. The CSTR is frequently used in research due to its simplicity in design and operation, but also for its advantages in experimentation. Compared to other configurations, the CSTR provides greater uniformity of system parameters, such as temperature, mixing, chemical concentration, and substrate concentration. Ultimately, when designing a full-scale reactor, the optimum reactor configuration will depend on the character of a given substrate among many other nontechnical considerations. However, all configurations share fundamental design features and operating parameters that render the CSTR appropriate for most preliminary assessments. If researchers and engineers use an influent stream with relatively high concentrations of solids, then lab-scale bioreactor configurations cannot be fed continuously due to plugging problems of lab-scale pumps with solids or settling of solids in tubing. For that scenario with continuous mixing requirements, lab-scale bioreactors are fed periodically and we refer to such configurations as continuously stirred anaerobic digesters (CSADs). This article presents a general

  11. [High Pressure Gas Tanks

    NASA Technical Reports Server (NTRS)

    Quintana, Rolando

    2002-01-01

    Four high-pressure gas tanks, the basis of this study, were especially made by a private contractor and tested before being delivered to NASA Kennedy Space Center. In order to insure 100% reliability of each individual tank the staff at KSC decided to again submit the four tanks under more rigorous tests. These tests were conducted during a period from April 10 through May 8 at KSC. This application further validates the predictive safety model for accident prevention and system failure in the testing of four high-pressure gas tanks at Kennedy Space Center, called Continuous Hazard Tracking and Failure Prediction Methodology (CHTFPM). It is apparent from the variety of barriers available for a hazard control that some barriers will be more successful than others in providing protection. In order to complete the Barrier Analysis of the system, a Task Analysis and a Biomechanical Study were performed to establish the relationship between the degree of biomechanical non-conformities and the anomalies found within the system on particular joints of the body. This relationship was possible to obtain by conducting a Regression Analysis to the previously generated data. From the information derived the body segment with the lowest percentage of non-conformities was the neck flexion with 46.7%. Intense analysis of the system was conducted including Preliminary Hazard Analysis (PHA), Failure Mode and Effect Analysis (FMEA), and Barrier Analysis. These analyses resulted in the identification of occurrences of conditions, which may be becoming hazardous in the given system. These conditions, known as dendritics, may become hazards and could result in an accident, system malfunction, or unacceptable risk conditions. A total of 56 possible dendritics were identified. Work sampling was performed to observe the occurrence each dendritic. The out of control points generated from a Weighted c control chart along with a Pareto analysis indicate that the dendritics "Personnel not

  12. Tank closure reducing grout

    SciTech Connect

    Caldwell, T.B.

    1997-04-18

    A reducing grout has been developed for closing high level waste tanks at the Savannah River Site in Aiken, South Carolina. The grout has a low redox potential, which minimizes the mobility of Sr{sup 90}, the radionuclide with the highest dose potential after closure. The grout also has a high pH which reduces the solubility of the plutonium isotopes. The grout has a high compressive strength and low permeability, which enhances its ability to limit the migration of contaminants after closure. The grout was designed and tested by Construction Technology Laboratories, Inc. Placement methods were developed by the Savannah River Site personnel.

  13. 39. DIABLO POWERHOUSE: GRAVITY LUBRICATING OIL TANKS. THESE TANKS ARE ...

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

    39. DIABLO POWERHOUSE: GRAVITY LUBRICATING OIL TANKS. THESE TANKS ARE LOCATED AT ROOF LEVEL AT THE NORTHEAST REAR CORNER OF DIABLO POWERHOUSE, 1989. - Skagit Power Development, Diablo Powerhouse, On Skagit River, 6.1 miles upstream from Newhalem, Newhalem, Whatcom County, WA

  14. Health effects of tank cleaners.

    PubMed

    Lillienberg, L; Högstedt, B; Järvholm, B; Nilson, L

    1992-06-01

    A total of 29 tank cleaners and 31 referent controls participated in the study. In most cases, the tank cleaners were employed in small companies, usually specialized subcontractors such as firms only working in refineries cleaning oil tanks and handling oil spills. The air concentrations of hydrocarbons (HCs) in tanks containing residuals from heavy fuel oil were generally low, unless the oil was still warm. Addition of light fuel oil to facilitate the cleaning of tanks containing viscous, heavy fuel oils resulted in total airborne HC levels of 1000-1500 mg/m3. High levels of HC were measured in tanks with low-boiling petroleum fractions (naphtha and light fuel oils) of 1000-2600 mg/m3 (maximum). Today, most cleaners use air-supplied respirators or air-purifying respirator cartridges inside tanks with petroleum products or other chemicals. The exception is small firms handling fuel oils for heating purposes where only 50% of the workers use protective equipment regularly; the other workers only occasionally use protective equipment even if the air concentrations of HC are high. Protective equipment is rarely used in small, domestic tanks. Measurements of heart rate showed that tank cleaning is, at times, a highly strenuous job. No differences between tank cleaners and controls were found with respect to spirometry, liver enzymes, or frequency of micronuclei. Acute intoxications were not frequently reported in this group. However, this investigation may underestimate the true risk, as it is a cross-sectional study that found that exposures were highly variable, both quantitatively and qualitatively. In many cases, the tank cleaners knew very little about the potential hazards or the proper use of protective equipment.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1605110

  15. SINDA/FLUINT Stratified Tank Modeling for Cryrogenic Propellant Tanks

    NASA Technical Reports Server (NTRS)

    Sakowski, Barbara

    2014-01-01

    A general purpose SINDA/FLUINT (S/F) stratified tank model was created to simulate self-pressurization and axial jet TVS; Stratified layers in the vapor and liquid are modeled using S/F lumps.; The stratified tank model was constructed to permit incorporating the following additional features:, Multiple or singular lumps in the liquid and vapor regions of the tank, Real gases (also mixtures) and compressible liquids, Venting, pressurizing, and draining, Condensation and evaporation/boiling, Wall heat transfer, Elliptical, cylindrical, and spherical tank geometries; Extensive user logic is used to allow detailed tailoring - Don't have to rebuilt everything from scratch!!; Most code input for a specific case is done through the Registers Data Block:, Lump volumes are determined through user input:; Geometric tank dimensions (height, width, etc); Liquid level could be input as either a volume percentage of fill level or actual liquid level height

  16. Microstructural Characterization of Friction Stir Welded Aluminum-Steel Joints

    NASA Astrophysics Data System (ADS)

    Patterson, Erin E.; Hovanski, Yuri; Field, David P.

    2016-06-01

    This work focuses on the microstructural characterization of aluminum to steel friction stir welded joints. Lap weld configuration coupled with scribe technology used for the weld tool have produced joints of adequate quality, despite the significant differences in hardness and melting temperatures of the alloys. Common to friction stir processes, especially those of dissimilar alloys, are microstructural gradients including grain size, crystallographic texture, and precipitation of intermetallic compounds. Because of the significant influence that intermetallic compound formation has on mechanical and ballistic behavior, the characterization of the specific intermetallic phases and the degree to which they are formed in the weld microstructure is critical to predicting weld performance. This study used electron backscatter diffraction, energy dispersive spectroscopy, scanning electron microscopy, and Vickers micro-hardness indentation to explore and characterize the microstructures of lap friction stir welds between an applique 6061-T6 aluminum armor plate alloy and a RHA homogeneous armor plate steel alloy. Macroscopic defects such as micro-cracks were observed in the cross-sectional samples, and binary intermetallic compound layers were found to exist at the aluminum-steel interfaces of the steel particles stirred into the aluminum weld matrix and across the interfaces of the weld joints. Energy dispersive spectroscopy chemical analysis identified the intermetallic layer as monoclinic Al3Fe. Dramatic decreases in grain size in the thermo-mechanically affected zones and weld zones that evidenced grain refinement through plastic deformation and recrystallization. Crystallographic grain orientation and texture were examined using electron backscatter diffraction. Striated regions in the orientations of the aluminum alloy were determined to be the result of the severe deformation induced by the complex weld tool geometry. Many of the textures observed in the weld

  17. Stirring-assisted assembly of nanowires at liquid-solid interfaces

    NASA Astrophysics Data System (ADS)

    Li, Wen-Ze; Wei, Wei; Chen, Jun-Yi; He, Ji-Xiang; Xue, Sheng-Nan; Zhang, Jing; Liu, Xia; Li, Xiang; Fu, Yu; Jiao, Yong-Hua; Zhang, Kai; Liu, Fuchun; Han, En-Hou

    2013-03-01

    The assembly of Ag nanowires on quartz substrates from suspensions of water and ethylene glycol under stirring has been investigated. The introduction of stirring makes a remarkable difference to the assembly morphology. Firstly, the surface coverage of Ag nanowires is increased by a factor of 4 (in water) and 8 (in ethylene glycol) with stirring. Secondly, the Ag nanowires assembled in the stirred ethylene glycol dispersion were highly aligned. The influence of the surface of substrates, solvents and profile of the nanowires on the alignment has been explored, which indicates that stirring is an efficient way to generate nanowire arrays. This study has revealed the great potential of the stirring-assisted assembly technique in producing structurally controlled nanoarchitectures, opening up new opportunities for manufacturing ordered nanomaterials.

  18. Filling an Unvented Cryogenic Tank

    NASA Technical Reports Server (NTRS)

    Beck, Phillip; Willen, Gary S.

    1987-01-01

    Slow-cooling technique enables tank lacking top vent to be filled with cryogenic liquid. New technique: pressure buildup prevented through condensation of accumulating gas resulting in condensate being added to bulk liquid. Filling method developed for vibration test on vacuum-insulated spherical tank containing liquid hydrogen.

  19. 1990 waste tank inspection program

    SciTech Connect

    McNatt, F.G.

    1990-12-31

    Aqueous radioactive wastes from Savannah River Site separations processes are contained in large underground carbon steel tanks. Tank conditions are evaluated by inspection using periscopes, still photography, and video systems for visual imagery. Inspections made in 1990 are the subject of this report.

  20. 1990 waste tank inspection program

    SciTech Connect

    McNatt, F.G.

    1990-01-01

    Aqueous radioactive wastes from Savannah River Site separations processes are contained in large underground carbon steel tanks. Tank conditions are evaluated by inspection using periscopes, still photography, and video systems for visual imagery. Inspections made in 1990 are the subject of this report.

  1. Main tank injection pressurization program

    NASA Technical Reports Server (NTRS)

    Cady, E. C.; Kendle, D. W.

    1972-01-01

    Computer program predicts performance of fluorine-hydrogen main tank injection pressurization system for full range of liquid-hydrogen-fueled space vehicles. Analytical model includes provisions for heat transfer, injectant jet penetration, and ullage gas mixing. Analysis predicts GF2 usage, ullage gas and tank wall temperatures, and LH2 evaporation.

  2. NOX5-L can stimulate proliferation and apoptosis depending on its levels and cellular context, determining cancer cell susceptibility to cisplatin

    PubMed Central

    Kwon, Eun-Soo; Lim, Jae Cheong; Park, Sung Sup; Kwon, Ki-Sun

    2015-01-01

    The NADPH oxidase, NOX5, is known to stimulate cell proliferation in some cancers by generating reactive oxygen species (ROS). We show here that the long form of NOX5 (NOX5-L) also promotes cell death, and thus determines the balance of proliferation and death, in skin, breast and lung cancer cells. Moderate expression of NOX5-L induced cell proliferation accompanied by AKT and ERK phosphorylation, whereas an increase in NOX5-L above a certain threshold promoted cancer cell death accompanied by caspase-3 activation. Notably, cisplatin treatment increased NOX5-L levels through CREB activation and enhanced NOX5-L activity through augmentation of Ca2+ release and c-Abl expression, ultimately triggering ROS-mediated cancer cell death—a distinct pathway absent in normal cells. These results indicate that NOX5-L determines cellular responses in a concentration- and context-dependent manner. PMID:26513170

  3. Investigation of the Microstructure of Joints of Aluminum Alloys Produced by Friction Stir Welding

    NASA Astrophysics Data System (ADS)

    Kolubaev, E. A.

    2015-02-01

    Special features of the microstructure of joints of aluminum-magnesium and aluminum-copper alloys produced by friction stir welding are analyzed. It is demonstrated that a layered structure with ultradisperse grains is produced by friction stir welding at the center of the weld joint. An analogy is drawn between the microstructures of joints produced by friction stir welding and surface layer produced by sliding friction.

  4. Supporting document for the Southeast Quadrant historical tank content estimate report for SY-tank farm

    SciTech Connect

    Brevick, C.H.; Gaddis, L.A.; Consort, S.D.

    1995-12-31

    Historical Tank Content Estimate of the Southeast Quadrant provides historical evaluations on a tank by tank basis of the radioactive mixed wastes stored in the underground double-shell tanks of the Hanford 200 East and West Areas. This report summarizes historical information such as waste history, temperature profiles, psychrometric data, tank integrity, inventory estimates and tank level history on a tank by tank basis. Tank Farm aerial photos and in-tank photos of each tank are provided. A brief description of instrumentation methods used for waste tank surveillance are included. Components of the data management effort, such as Waste Status and Transaction Record Summary, Tank Layer Model, Supernatant Mixing Model, Defined Waste Types, and Inventory Estimates which generate these tank content estimates, are also given in this report.

  5. CST Suspension Analysis for Slurry Pumps of Tank 40

    SciTech Connect

    LEE, SIY.

    2004-04-01

    result s. The model results show that at least two pumps on opposite sides could keep suspending the CST material based on the slurry with 35 wt contents, but that at lower concentrations, particles larger than about 400 microns would tend to settle quickly and probably not remain in suspension long enough for the opposite jet to come around and stir that region of the tank. The main conclusions are as follows: The steady-state flow patterns on the horizontal discharge plane follow a series of parabolic curves similar to that of a free jet available in the literature. For the simulations, a series of the modeling calculations was performed with indexed stationary and rotating pump operations. The calculated results demonstrated that the existing slurry pumps running at 7600 gpm could suspend the CST particles from the tank with a 200 in liquid level, based on a minimum sludge suspension velocity of about 1.1 ft/sec for 700 micron CST particle. The suspension distance for the transient model with pump rotations is smaller than that of the steady-state model with indexed pump orientations for given operating conditions. However, total suspension extents for the two modeling cases have about the same area.

  6. Insulated solar storage tanks

    SciTech Connect

    Eldighidy, S.M. )

    1991-01-01

    This paper presents the theoretical and experimental investigation of an insulated parallelepiped, outdoor solar, water-filled storage tank of size 1 m {times} 0.5 m {times} 0.3 m, that is made from galvanized iron. The absorption coefficient of the insulating material has been determined. The effects of plastic covers and insulation thickness on the water temperature and the energy gained or lost by water are investigated. Moreover, the effects of insulation thickness on the temperature profiles of the insulating material are discussed. The results show that the absorption coefficient decreases as the insulation thickness increases. Also, it is found that the glass wool insulation of 2.5 cm thickness has the best results compared with the other thicknesses (5 cm, 7.5 cm, and 10 cm) as far as the water temperature and the energy gained by water are concerned.

  7. Tank farms hazards assessment

    SciTech Connect

    Broz, R.E.

    1994-09-30

    Hanford contractors are writing new facility specific emergency procedures in response to new and revised US Department of Energy (DOE) Orders on emergency preparedness. Emergency procedures are required for each Hanford facility that has the potential to exceed the criteria for the lowest level emergency, an Alert. The set includes: (1) a facility specific procedure on Recognition and Classification of Emergencies, (2) area procedures on Initial Emergency Response and, (3) an area procedure on Protective Action Guidance. The first steps in developing these procedures are to identify the hazards at each facility, identify the conditions that could release the hazardous material, and calculate the consequences of the releases. These steps are called a Hazards Assessment. The final product is a document that is similar in some respects to a Safety Analysis Report (SAR). The document could br produced in a month for a simple facility but could take much longer for a complex facility. Hanford has both types of facilities. A strategy has been adopted to permit completion of the first version of the new emergency procedures before all the facility hazards Assessments are complete. The procedures will initially be based on input from a task group for each facility. This strategy will but improved emergency procedures in place sooner and therefore enhance Hanford emergency preparedness. The purpose of this document is to summarize the applicable information contained within the Waste Tank Facility ``Interim Safety Basis Document, WHC-SD-WM-ISB-001`` as a resource, since the SARs covering Waste Tank Operations are not current in all cases. This hazards assessment serves to collect, organize, document and present the information utilized during the determination process.

  8. 49 CFR 180.519 - Periodic retest and inspection of tank cars other than single-unit tank car tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Periodic retest and inspection of tank cars other... § 180.519 Periodic retest and inspection of tank cars other than single-unit tank car tanks. (a) General... periodically as specified in Retest Table 1 of paragraph (b)(5) of this section. Retests may be made at...

  9. 49 CFR 180.519 - Periodic retest and inspection of tank cars other than single-unit tank car tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Periodic retest and inspection of tank cars other... of Tank Cars § 180.519 Periodic retest and inspection of tank cars other than single-unit tank car... devices must be retested periodically as specified in Retest Table 1 of paragraph (b)(5) of this...

  10. Friction Stir Welding of Metal Matrix Composites for use in aerospace structures

    NASA Astrophysics Data System (ADS)

    Prater, Tracie

    2014-01-01

    Friction Stir Welding (FSW) is a relatively nascent solid state joining technique developed at The Welding Institute (TWI) in 1991. The process was first used at NASA to weld the super lightweight external tank for the Space Shuttle. Today FSW is used to join structural components of the Delta IV, Atlas V, and Falcon IX rockets as well as the Orion Crew Exploration Vehicle. A current focus of FSW research is to extend the process to new materials which are difficult to weld using conventional fusion techniques. Metal Matrix Composites (MMCs) consist of a metal alloy reinforced with ceramics and have a very high strength to weight ratio, a property which makes them attractive for use in aerospace and defense applications. MMCs have found use in the space shuttle orbiter's structural tubing, the Hubble Space Telescope's antenna mast, control surfaces and propulsion systems for aircraft, and tank armors. The size of MMC components is severely limited by difficulties encountered in joining these materials using fusion welding. Melting of the material results in formation of an undesirable phase (formed when molten Aluminum reacts with the reinforcement) which leaves a strength depleted region along the joint line. Since FSW occurs below the melting point of the workpiece material, this deleterious phase is absent in FSW-ed MMC joints. FSW of MMCs is, however, plagued by rapid wear of the welding tool, a consequence of the large discrepancy in hardness between the steel tool and the reinforcement material. This work characterizes the effect of process parameters (spindle speed, traverse rate, and length of joint) on the wear process. Based on the results of these experiments, a phenomenological model of the wear process was constructed based on the rotating plug model for FSW. The effectiveness of harder tool materials (such as Tungsten Carbide, high speed steel, and tools with diamond coatings) to combat abrasive wear is explored. In-process force, torque, and

  11. On the fluid dynamics of a laboratory scale single-use stirred bioreactor

    PubMed Central

    Odeleye, A.O.O.; Marsh, D.T.J.; Osborne, M.D.; Lye, G.J.; Micheletti, M.

    2014-01-01

    The commercial success of mammalian cell-derived recombinant proteins has fostered an increase in demand for novel single-use bioreactor (SUB) systems that facilitate greater productivity, increased flexibility and reduced costs (Zhang et al., 2010). These systems exhibit fluid flow regimes unlike those encountered in traditional glass/stainless steel bioreactors because of the way in which they are designed. With such disparate hydrodynamic environments between SUBs currently on the market, traditional scale-up approaches applied to stirred tanks should be revised. One such SUB is the Mobius® 3 L CellReady, which consists of an upward-pumping marine scoping impeller. This work represents the first experimental study of the flow within the CellReady using a Particle Image Velocimetry (PIV) approach, combined with a biological study into the impact of these fluid dynamic characteristics on cell culture performance. The PIV study was conducted within the actual vessel, rather than using a purpose-built mimic. PIV measurements conveyed a degree of fluid compartmentalisation resulting from the up-pumping impeller. Both impeller tip speed and fluid working volume had an impact upon the fluid velocities and spatial distribution of turbulence within the vessel. Cell cultures were conducted using the GS-CHO cell-line (Lonza) producing an IgG4 antibody. Disparity in cellular growth and viability throughout the range of operating conditions used (80–350 rpm and 1–2.4 L working volume) was not substantial, although a significant reduction in recombinant protein productivity was found at 350 rpm and 1 L working volume (corresponding to the highest Reynolds number tested in this work). The study shows promise in the use of PIV to improve understanding of the hydrodynamic environment within individual SUBs and allows identification of the critical hydrodynamic parameters under the different flow regimes for compatibility and scalability across the range of bioreactor

  12. Controlling Force and Depth in Friction Stir Welding

    NASA Technical Reports Server (NTRS)

    Adams, Glynn; Loftus, Zachary; McCormac, Nathan; Venable, Richard

    2005-01-01

    Feedback control of the penetration force applied to a pin tool in friction stir welding has been found to be a robust and reliable means for controlling the depth of penetration of the tool. This discovery has made it possible to simplify depth control and to weld with greater repeatability, even on workpieces with long weld joints. Prior to this discovery, depths of penetration in friction stir welding were controlled by hard-tooled roller assemblies or by depth actuators controlled by feedback from such external sensors as linear variable-differential transformers or laser-based devices. These means of control are limited: A hard-tooled roller assembly confines a pin tool to a preset depth that cannot be changed easily during the welding process. A measurement by an external sensor is only an indirect indicative of the depth of penetration, and computations to correlate such a measurement with a depth of penetration are vulnerable to error. The present force-feedback approach exploits the proportionality between the depth and the force of penetration Unlike a depth measurement taken by an external sensor, a force measurement can be direct because it can be taken by a sensor coupled directly to the pin tool. The reading can be processed through a modern electronic servo control system to control an actuator to keep the applied penetration force at the desired level. In comparison with the older depth-control methods described above, this method offers greater sensitivity to plasticizing of the workpiece metal and is less sensitive to process noise, resulting in a more consistent process. In an experiment, a tapered panel was friction stir welded while controlling the force of penetration according to this method. The figure is a plot of measurements taken during the experiment, showing that force was controlled with a variation of 200 lb (890 N), resulting in control of the depth of penetration with a variation of 0.004 in. (0.1 mm).

  13. Reactivity of Primary Soil Minerals and Secondary Precipitates Beneath Leaking Hanford Waste Tanks

    SciTech Connect

    Nagy, Kathryn L.; Sturchio, Neil C.

    2003-06-01

    This project, renewal of a previous EMSP project of the same title, is in its first year of funding at the University of Illinois at Chicago. The purpose is to continue investigating rates and mechanisms of reactions between primary sediment minerals found in the Hanford subsurface and leaked waste tank solutions. The goals are to understand processes that result in (1) changes in porosity and permeability of the sediment and resultant changes in flow paths of the contaminant plumes, (2) formation of secondary precipitates that can take up contaminants in their structures, and (3) release of mineral components that can drive redox reactions affecting dissolved contaminant mobility. A post-doctoral scientist, Dr. Sherry Samson, has been hired and two masters of science students are beginning to conduct experimental research. One research project that is underway is focused on measurement of the dissolution rates of plagioclase feldspar in high pH, high nitrate, high Al-bearing solutions characteristic of the BX tank farms. The first set of experiments is being conduced at room temperature. Subsequent experiments will examine the role of temperature because tank solutions in many cases were near boiling when leakage is thought to have occurred and temperature gradients have been observed beneath the SX and BX tank farms. The dissolution experiments are being conducted in stirred-flow kinetic reactors using powdered labradorite feldspar from Pueblo Park, New Mexico.

  14. Developing Friction Stir Welding Process Model for ICME Application

    NASA Astrophysics Data System (ADS)

    Yang, Yu-Ping

    2015-01-01

    A framework for developing a product involving manufacturing processes was developed with integrated computational materials engineering approach. The key component in the framework is a process modeling tool which includes a thermal model, a microstructure model, a thermo-mechanical, and a property model. Using friction stir welding (FSW) process as an example, development of the process modeling tool was introduced in detail. The thermal model and the microstructure model of FSW of steels were validated with the experiment data. The model can predict reasonable temperature and hardness distributions as observed in the experiment. The model was applied to predict residual stress and joint strength of a pipe girth weld.

  15. Friction stir welding tool and process for welding dissimilar materials

    DOEpatents

    Hovanski, Yuri; Grant, Glenn J; Jana, Saumyadeep; Mattlin, Karl F

    2013-05-07

    A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

  16. Fatigue Crack Growth in Peened Friction Stir Welds

    NASA Technical Reports Server (NTRS)

    Forth, Scott C.; Hatamleh, Omar

    2008-01-01

    Friction stir welding induces residual stresses that accelerates fatigue crack growth in the weld nugget. Shot peening over the weld had little effect on growth rate. Laser peening over the weld retarded the growth rate: Final crack growth rate was comparable to the base, un-welded material. Crack tunneling evident from residual compressive stresses. 2195-T8 fracture surfaces were highly textured. Texturing makes comparisons difficult as the material system is affecting the data as much as the processing. Material usage becoming more common in space applications requiring additional work to develop useful datasets for damage tolerance analyses.

  17. Production of verruculogen by Penicillium estinogenum in stirred fermenters.

    PubMed

    Day, J B; Mantle, P G; Shaw, B I

    1980-04-01

    A spectrofluorometric assay for the estimation of the tremorgenic mycotoxin verruculogen in crude mycelial extract has been devised and used to determine concentrations as low as 0.2 microgram ml-1. Verruculogen production by Penicillium estinogenum has been extended from surface culture to submerged culture in 60 1 stirred fermenters, in which the maximum cell-associated mycotoxin yield [5 mg (100 ml culture)-1] was obtained within 7 d. It was found necessary to supplement the medium (Czapek Dox broth plus 0.5% yeast extract) with calcium chloride (2%) to induce profuse sporulation (2 X 10(7) conidia ml-1). PMID:7420051

  18. Tank characterization report for single shell tank 241-S-107

    SciTech Connect

    Simpson, B.C.

    1996-09-19

    This document summarizes the information on the historical uses, present status, and the sampling and analysis results of waste stored in Tank 241-S-107. This report supports the requirements of Tri- Party Agreement Milestone M-44-09.

  19. 33 CFR 157.15 - Slop tanks in tank vessels.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... affecting § 157.15, see the List of CFR Sections Affected, which appears in the Finding Aids section of the... washing water. (c) Design. A slop tank required in this section: (1) Must minimize turbulence,...

  20. 33 CFR 157.15 - Slop tanks in tank vessels.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... affecting § 157.15, see the List of CFR Sections Affected, which appears in the Finding Aids section of the... washing water. (c) Design. A slop tank required in this section: (1) Must minimize turbulence,...