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Sample records for entrained bed process

  1. Research on the pyrolysis of hardwood in an entrained bed process development unit

    SciTech Connect

    Kovac, R.J.; Gorton, C.W.; Knight, J.A.; Newman, C.J.; O'Neil, D.J. . Research Inst.)

    1991-08-01

    An atmospheric flash pyrolysis process, the Georgia Tech Entrained Flow Pyrolysis Process, for the production of liquid biofuels from oak hardwood is described. The development of the process began with bench-scale studies and a conceptual design in the 1978--1981 timeframe. Its development and successful demonstration through research on the pyrolysis of hardwood in an entrained bed process development unit (PDU), in the period of 1982--1989, is presented. Oil yields (dry basis) up to 60% were achieved in the 1.5 ton-per-day PDU, far exceeding the initial target/forecast of 40% oil yields. Experimental data, based on over forty runs under steady-state conditions, supported by material and energy balances of near-100% closures, have been used to establish a process model which indicates that oil yields well in excess of 60% (dry basis) can be achieved in a commercial reactor. Experimental results demonstrate a gross product thermal efficiency of 94% and a net product thermal efficiency of 72% or more; the highest values yet achieved with a large-scale biomass liquefaction process. A conceptual manufacturing process and an economic analysis for liquid biofuel production at 60% oil yield from a 200-TPD commercial plant is reported. The plant appears to be profitable at contemporary fuel costs of $21/barrel oil-equivalent. Total capital investment is estimated at under $2.5 million. A rate-of-return on investment of 39.4% and a pay-out period of 2.1 years has been estimated. The manufacturing cost of the combustible pyrolysis oil is $2.70 per gigajoule. 20 figs., 87 tabs.

  2. An integrated process for hydrogen-rich gas production from cotton stalks: The simultaneous gasification of pyrolysis gases and char in an entrained flow bed reactor.

    PubMed

    Chen, Zhiyuan; Zhang, Suping; Chen, Zhenqi; Ding, Ding

    2015-12-01

    An integrated process (pyrolysis, gas-solid simultaneous gasification and catalytic steam reforming) was utilized to produce hydrogen-rich gas from cotton stalks. The simultaneous conversion of the pyrolysis products (char and pyrolysis gases) was emphatically investigated using an entrained flow bed reactor. More carbon of char is converted into hydrogen-rich gas in the simultaneous conversion process and the carbon conversion is increased from 78.84% to 92.06% compared with the two stages process (pyrolysis and catalytic steam reforming). The distribution of tar components is also changed in this process. The polycyclic aromatic compounds (PACs) of tar are converted into low-ring compounds or even chain compounds due to the catalysis of char. In addition, the carbon deposition yield over NiO/MgO catalyst in the steam reforming process is approximately 4 times higher without the simultaneous process. The potential H2 yield increases from 47.71 to 78.19g/kg cotton stalks due to the simultaneous conversion process.

  3. An integrated process for hydrogen-rich gas production from cotton stalks: The simultaneous gasification of pyrolysis gases and char in an entrained flow bed reactor.

    PubMed

    Chen, Zhiyuan; Zhang, Suping; Chen, Zhenqi; Ding, Ding

    2015-12-01

    An integrated process (pyrolysis, gas-solid simultaneous gasification and catalytic steam reforming) was utilized to produce hydrogen-rich gas from cotton stalks. The simultaneous conversion of the pyrolysis products (char and pyrolysis gases) was emphatically investigated using an entrained flow bed reactor. More carbon of char is converted into hydrogen-rich gas in the simultaneous conversion process and the carbon conversion is increased from 78.84% to 92.06% compared with the two stages process (pyrolysis and catalytic steam reforming). The distribution of tar components is also changed in this process. The polycyclic aromatic compounds (PACs) of tar are converted into low-ring compounds or even chain compounds due to the catalysis of char. In addition, the carbon deposition yield over NiO/MgO catalyst in the steam reforming process is approximately 4 times higher without the simultaneous process. The potential H2 yield increases from 47.71 to 78.19g/kg cotton stalks due to the simultaneous conversion process. PMID:26433156

  4. Entrainment of bed sediment by debris flows: results from large-scale experiments

    USGS Publications Warehouse

    Reid, Mark E.; Iverson, Richard M.; Logan, Matthew; LaHusen, Richard G.; Godt, Jonathan W.; Griswold, Julie P.

    2011-01-01

    When debris flows grow by entraining sediment, they can become especially hazardous owing to increased volume, speed, and runout. To investigate the entrainment process, we conducted eight largescale experiments in the USGS debris-flow flume. In each experiment, we released a 6 m3 water-saturated debris flow across a 47-m long, ~12-cm thick bed of partially saturated sediment lining the 31º flume. Prior to release, we used low-intensity overhead sprinkling and real-time monitoring to control the bed-sediment wetness. As each debris flow descended the flume, we measured the evolution of flow thickness, basal total normal stress, basal pore-fluid pressure, and sediment scour depth. When debris flows traveled over relatively dry sediment, net scour was minimal, but when debris flows traveled over wetter sediment (volumetric water content > 0.22), debris-flow volume grew rapidly and flow speed and runout were enhanced. Data from scour sensors showed that entrainment occurred by rapid (5-10 cm/s), progressive scour rather than by mass failure at depth. Overriding debris flows rapidly generated high basal pore-fluid pressures when they loaded and deformed bed sediment, and in wetter beds these pressures approached lithostatic levels. Reduction of intergranular friction within the bed sediment thereby enhanced scour efficiency, entrainment, and runout.

  5. An analysis of the entrainment effect of dry debris avalanches on loose bed materials.

    PubMed

    Lu, Peng-Yuan; Yang, Xing-Guo; Xu, Fu-Gang; Hou, Tian-Xing; Zhou, Jia-Wen

    2016-01-01

    Substrate entrainment can greatly influence the mass movement process of a debris avalanche because it can enlarge the landslide volume and change the motion characteristics of the sliding masses. To study the interaction between debris avalanches and erodible substrate, physical modeling experiments varying in the mass of granular flow and substrate thickness were performed. The experimental results show that both the entrained materials and the maximum erosion depth are increased with increasing mass of the debris avalanche and decreasing substrate thickness. During the experiment, several tests were recorded using a high-speed digital camera with a frequency of 500 frames per second, so that the process of entrainment could be clearly observed. Combined with the experiment result and results of previous studies from predecessors, the entrainment mechanism during debris avalanches are analyzed and discussed. The entrainment effect of the sliding masses on the loose bed materials include basal abrasion and impact erosion of the avalanche front, the latter of which can contribute to the former by failing or yielding the erodible bed.

  6. An analysis of the entrainment effect of dry debris avalanches on loose bed materials.

    PubMed

    Lu, Peng-Yuan; Yang, Xing-Guo; Xu, Fu-Gang; Hou, Tian-Xing; Zhou, Jia-Wen

    2016-01-01

    Substrate entrainment can greatly influence the mass movement process of a debris avalanche because it can enlarge the landslide volume and change the motion characteristics of the sliding masses. To study the interaction between debris avalanches and erodible substrate, physical modeling experiments varying in the mass of granular flow and substrate thickness were performed. The experimental results show that both the entrained materials and the maximum erosion depth are increased with increasing mass of the debris avalanche and decreasing substrate thickness. During the experiment, several tests were recorded using a high-speed digital camera with a frequency of 500 frames per second, so that the process of entrainment could be clearly observed. Combined with the experiment result and results of previous studies from predecessors, the entrainment mechanism during debris avalanches are analyzed and discussed. The entrainment effect of the sliding masses on the loose bed materials include basal abrasion and impact erosion of the avalanche front, the latter of which can contribute to the former by failing or yielding the erodible bed. PMID:27652194

  7. Process of entrainment in particulate gravity currents

    NASA Astrophysics Data System (ADS)

    Shringarpure, Mrugesh; Salinas, Jorge; Cantero, Mariano; Balachandar, S.

    2014-11-01

    Various geophysical flows like turbidity currents, river flows, dust storms etc transport huge quantities of dispersed phase over large distances. Typically in such flows a dispersed phase rich layer is swept along with the flow. The amount of dispersed phase carried depends on the dynamics of this layer which are governed by a strong coupling between turbulence and suspended particles. This layer evolves, i.e., grows/shrinks in size, due to entrainment/detrainment of surrounding clear fluid at its interface (where a sharp change from particle rich fluid to surrounding clear fluid occurs). Also in many applications there is entrainment and detainment of particles at the bottom boundary due to settling and resuspension. The entrainment processes that occur here have important consequences. Consistent entrainment means the flow is energetic enough to mix/distribute the dispersed phase layer in the bulk flow. To study these processes, we introduce a layer of suspended particles into a fully turbulent channel flow and capture the entrainment processes in detail. Three parameters - Reynolds number, particle size and Richardson number dictate the entrainment process. Various simulations have been performed that explores this parametric space and identifies various entrainment regimes. We acknowledge support from US NSF through Grant OISE 0968313 and OCE 1131016.

  8. Positive feedback and momentum growth during debris-flow entrainment of wet bed sediment

    USGS Publications Warehouse

    Iverson, R.M.; Reid, M.E.; Logan, M.; LaHusen, R.G.; Godt, J.W.; Griswold, J.P.

    2011-01-01

    Debris flows typically occur when intense rainfall or snowmelt triggers landslides or extensive erosion on steep, debris-mantled slopes. The flows can then grow dramatically in size and speed as they entrain material from their beds and banks, but the mechanism of this growth is unclear. Indeed, momentum conservation implies that entrainment of static material should retard the motion of the flows if friction remains unchanged. Here we use data from large-scale experiments to assess the entrainment of bed material by debris flows. We find that entrainment is accompanied by increased flow momentum and speed only if large positive pore pressures develop in wet bed sediments as the sediments are overridden by debris flows. The increased pore pressure facilitates progressive scour of the bed, reduces basal friction and instigates positive feedback that causes flow speed, mass and momentum to increase. If dryer bed sediment is entrained, however, the feedback becomes negative and flow momentum declines. We infer that analogous feedbacks could operate in other types of gravity-driven mass flow that interact with erodible beds. ?? 2011 Macmillan Publishers Limited. All rights reserved.

  9. Entrainment.

    ERIC Educational Resources Information Center

    Carrier, Romance F.

    1978-01-01

    Presents a literature review including: (1) theoretical studies concerned with the development of methdology to determine the significance of entrainment effects to whale populations and ecosystems; and (2) site and laboratory studies. A list of 107 references drawn from the 1976 and 1977 literature is also presented. (HM)

  10. Bed-material entrainment potential, Roaring Fork River at Basalt, Colorado

    USGS Publications Warehouse

    Elliott, John G.

    2002-01-01

    The Roaring Fork River at Basalt, Colorado, has a frequently mobile streambed composed of gravel, cobbles, and boulders. Recent urban and highway development on the flood plain, earlier attempts to realign and confine the channel, and flow obstructions such as bridge openings and piers have altered the hydrology, hydraulics, sediment transport, and sediment deposition areas of the Roaring Fork. Entrainment and deposition of coarse sediment on the streambed and in large alluvial bars have reduced the flood-conveying capacity of the river. Previous engineering studies have identified flood-prone areas and hazards related to inundation and high streamflow velocity, but those studies have not evaluated the potential response of the channel to discharges that entrain the coarse streambed. This study builds upon the results of earlier flood studies and identifies some potential areas of concern associated with bed-material entrainment. Cross-section surveys and simulated water-surface elevations from a previously run HEC?RAS model were used to calculate the boundary shear stress on the mean streambed, in the thalweg, and on the tops of adjacent alluvial bars for four reference streamflows. Sediment-size characteristics were determined for surficial material on the streambed, on large alluvial bars, and on a streambank. The median particle size (d50) for the streambed samples was 165 millimeters and for the alluvial bars and bank samples was 107 millimeters. Shear stresses generated by the 10-, 50-, and 100-year floods, and by a more common flow that just inundated most of the alluvial bars in the study reach were calculated at 14 of the cross sections used in the Roaring Fork River HEC?RAS model. The Shields equation was used with a Shields parameter of 0.030 to estimate the critical shear stress for entrainment of the median sediment particle size on the mean streambed, in the thalweg, and on adjacent alluvial bar surfaces at the 14 cross sections. Sediment-entrainment

  11. Development of an entrained flow gasifier model for process optimization study

    SciTech Connect

    Biagini, E.; Bardi, A.; Pannocchia, G.; Tognotti, L.

    2009-10-15

    Coal gasification is a versatile process to convert a solid fuel in syngas, which can be further converted and separated in hydrogen, which is a valuable and environmentally acceptable energy carrier. Different technologies (fixed beds, fluidized beds, entrained flow reactors) are used, operating under different conditions of temperature, pressure, and residence time. Process studies should be performed for defining the best plant configurations and operating conditions. Although 'gasification models' can be found in the literature simulating equilibrium reactors, a more detailed approach is required for process analysis and optimization procedures. In this work, a gasifier model is developed by using AspenPlus as a tool to be implemented in a comprehensive process model for the production of hydrogen via coal gasification. It is developed as a multizonal model by interconnecting each step of gasification (preheating, devolatilization, combustion, gasification, quench) according to the reactor configuration, that is in entrained flow reactor. The model removes the hypothesis of equilibrium by introducing the kinetics of all steps and solves the heat balance by relating the gasification temperature to the operating conditions. The model allows to predict the syngas composition as well as quantity the heat recovery (for calculating the plant efficiency), 'byproducts', and residual char. Finally, in view of future works, the development of a 'gasifier model' instead of a 'gasification model' will allow different reactor configurations to be compared.

  12. Bed particle entrainment and motion in turbulent open-channel flows: a high-resolution experimental study

    NASA Astrophysics Data System (ADS)

    Nikora, Vladimir; Cameron, Stuart; Amir, Mohammad; Stewart, Mark; Witz, Matthew

    2015-04-01

    In spite of significant efforts of geoscientists and engineers, the exact mechanics of sediment entrainment and transport by turbulent flows remains unclear and continues to be the focus of many research groups worldwide. The talk outlines current developments in this direction at the University of Aberdeen, where an extensive experimental programme has recently been completed. The experiments were conducted in the Aberdeen Open Channel Facility (AOCF, 20 m long, 1.18 m wide) over wide ranges of flow submergence (1.9-8.0), bulk Reynolds number (4400-83000), and channel aspect ratio (9-39). The flume bed was covered by hexagonally-packed glass beads 16 mm in diameter. For entrainment experiments, selected glass particles were replaced with lighter particles (nylon and delrin). Instantaneous velocity fields before, during, and after entrainment were measured with an advanced multi-mode Particle Image Velocimetry (PIV) system developed by S. Cameron. This system was also used for 3D particle tracking in the entrainment experiments. The main types of experiments included: (1) multi-mode turbulence measurements with fixed-bed conditions to assess the background flow structure (10 min to 120 min duration of velocity records); (2) simultaneous measurements of fluctuating differential pressure acting on 23 fixed particles with in-built pressure sensors, synchronously with PIV; (3) measurements of waiting times for particle entrainment, employing a specially designed system (SMC-1) for automatic placement of the particles on the bed and subsequent measurement of the time before entrainment; (4) long-term direct measurements of the instantaneous drag force acting on a single particle (attached to the bed) at different protrusions, synchronously with PIV; and (5) synchronous measurements of the flow field around a particle before, at, and during entrainment, supplemented with 3D particle tracking. The key results include: (1) the refined turbulence structure of a rough-bed

  13. Creepy landscapes : river sediment entrainment develops granular flow rheology on creeping bed.

    NASA Astrophysics Data System (ADS)

    Prancevic, J.; Chatanantavet, P.; Ortiz, C. P.; Houssais, M.; Durian, D. J.; Jerolmack, D. J.

    2015-12-01

    To predict rates of river sediment transport, one must first address the zeroth-order question: when does sediment move? The concept and determination of the critical fluid shear stress remains hazy, as observing particle motion and determining sediment flux becomes increasingly hard in its vicinity. To tackle this problem, we designed a novel annular flume experiment - reproducing an infinite river channel - where the refractive index of particles and the fluid are matched. The fluid is dyed with a fluorescent powder and a green laser sheet illuminates the fluid only, allowing us to observe particle displacements in a vertical plane. Experiments are designed to highlight the basic granular interactions of sediment transport while suppressing the complicating effects of turbulence; accordingly, particles are uniform spheres and Reynolds numbers are of order 1. We have performed sediment transport measurements close to the onset of particle motion, at steady state, and over long enough time to record averaged rheological behavior of particles. We find that particles entrained by a fluid exhibit successively from top to bottom: a suspension regime, a dense granular flow regime, and - instead of a static bed - a creeping regime. Data from experiments at a range of fluid stresses can be collapsed onto one universal rheologic curve that indicates the effective friction is a monotonic function of a dimensionless number called the viscous number. These data are in remarkable agreement with the local rheology model proposed by Boyer et al., which means that dense granular flows, suspensions and bed-load transport are unified under a common frictional flow law. Importantly, we observe slow creeping of the granular bed even in the absence of bed load, at fluid stresses that are below the apparent critical value. This last observation challenges the classical definition of the onset of sediment transport, and points to a continuous transition from quasi-static deformation to

  14. The Macroscopic Entrainment Processes of Simulated Cumulus Ensemble. Part II: Testing the Entraining-Plume Model.

    NASA Astrophysics Data System (ADS)

    Lin, Chichung; Arakawa, Akio

    1997-04-01

    According to Part I of this paper, it seems that ignoring the contribution from descendent cloud air in a cloud model for cumulus parameterization (CMCP), such as the spectral cumulus ensemble model in the Arakawa-Schubert parameterization, is an acceptable simplification for tropical deep convection. Since each subensemble in the spectral cumulus ensemble model is formally analogous to an entraining plume, the latter is examined using the simulated data from a cloud-resolving model (CRM). The authors first follow the analysis procedure of Warner. With the data from a nonprecipitating experiment, the authors show that the entraining-plume model cannot simultaneously predict the mean liquid water profile and cloud top height of the clouds simulated by the CRM. However, the mean properties of active elements of clouds, which are characterized by strong updrafts, can be described by an entraining plume of similar top height.With the data from a precipitating experiment, the authors examine the spectral cumulus ensemble model using the Paluch diagram. It is found that the spectral cumulus ensemble model appears adequate if different types of clouds in the spectrum are interpreted as subcloud elements with different entrainment characteristics. The resolved internal structure of clouds can thus be viewed as a manifestation of a cloud spectrum. To further investigate whether the fractional rate of entrainment is an appropriate parameter for characterizing cloud types in the spectral cumulus ensemble model, the authors stratify the simulated saturated updrafts (subcloud elements) into different types according to their eventual heights and calculate the cloud mass flux and mean moist static energy for each type. Entrainment characteristics are then inferred through the cloud mass flux and in-cloud moist static energy. It is found that different types of subcloud elements have distinguishable thermodynamic properties and entrainment characteristics. However, for each cloud

  15. Partial entrainment of gravel bars during floods

    USGS Publications Warehouse

    Konrad, C.P.; Booth, D.B.; Burges, S.J.; Montgomery, D.R.

    2002-01-01

    Spatial patterns of bed material entrainment by floods were documented at seven gravel bars using arrays of metal washers (bed tags) placed in the streambed. The observed patterns were used to test a general stochastic model that bed material entrainment is a spatially independent, random process where the probability of entrainment is uniform over a gravel bar and a function of the peak dimensionless shear stress ??*0 of the flood. The fraction of tags missing from a gravel bar during a flood, or partial entrainment, had an approximately normal distribution with respect to ??*0 with a mean value (50% of the tags entrained) of 0.085 and standard deviation of 0.022 (root-mean-square error of 0.09). Variation in partial entrainment for a given ??*0 demonstrated the effects of flow conditioning on bed strength, with lower values of partial entrainment after intermediate magnitude floods (0.065 < ??*0 < 0.08) than after higher magnitude floods. Although the probability of bed material entrainment was approximately uniform over a gravel bar during individual floods and independent from flood to flood, regions of preferential stability and instability emerged at some bars over the course of a wet season. Deviations from spatially uniform and independent bed material entrainment were most pronounced for reaches with varied flow and in consecutive floods with small to intermediate magnitudes.

  16. Fecal Indicator Bacteria Entrainment from Streambed to Water Column: Transport by Unsteady Flow over a Sand Bed.

    PubMed

    Surbeck, Cristiane Q; Douglas Shields, F; Cooper, Alexandra M

    2016-05-01

    Storms cause a substantial increase in the fecal indicator bacteria (FIB) concentrations in stream water as a result of FIB-laden runoff and the release of FIB from stream sediments. Previous work has emphasized the association between FIB and bed sediments finer than sand. The objectives of this work were to elucidate the effect of various velocities on the entrainment of bed-dwelling coliforms in sand-bed streams and to refine methodologies for quantifying sandy streambeds as sources of FIB. Pump-induced hydrographs were created using a stainless steel nonrecirculating flume. Experiments consisted of simulating four storm hydrographs and collecting water samples upstream and downstream of a sand bed at selected intervals. Bed sediment samples were collected before and after each event. The highest concentrations of total coliform and suspended sediments generally occurred in the downstream samples during the rising limb of the hydrographs as a result of entrainment of coliforms and sand from the bed to the water column. There was a first flush effect in the system, as the upper layer of sand was influenced by a rapidly increasing velocity at ∼0.2 m s. Coliforms downstream of the sand bed increased rapidly as velocity exceeded this threshold but then declined even as velocity and discharge continued to increase. This likely reflects the depletion of coliforms as the more densely populated sediment layer was flushed out. There is evidence that streams with sand beds harbor enough FIB that development of total maximum daily loads (TMDLs) should include consideration of them as a source. PMID:27136173

  17. Bed-material entrainment and associated transportation infrastructure problems in streams of the Edwards Plateau, central Texas

    USGS Publications Warehouse

    Heitmuller, Franklin T.; Asquith, William H.

    2008-01-01

    The Texas Department of Transportation commonly builds and maintains low-water crossings (LWCs) over streams in the Edwards Plateau in Central Texas. LWCs are low-height structures, typically constructed of concrete and asphalt, that provide acceptable passage over seasonal rivers or streams with relatively low normal-depth flow. They are designed to accommodate flow by roadway overtopping during high-flow events. The streams of the Edwards Plateau are characterized by cobble- and gravel-sized bed material and highly variable flow regimes. Low base flows that occur most of the time occasionally are interrupted by severe floods. The floods entrain and transport substantial loads of bed material in the stream channels. As a result, LWCs over streams in the Edwards Plateau are bombarded and abraded by bed material during floods and periodically must be maintained or even replaced.

  18. Potential for bed-material entrainment in selected streams of the Edwards Plateau - Edwards, Kimble, and Real Counties, Texas, and vicinity

    USGS Publications Warehouse

    Heitmuller, Franklin T.; Asquith, William H.

    2008-01-01

    The Texas Department of Transportation spends considerable money for maintenance and replacement of low-water crossings of streams in the Edwards Plateau in Central Texas as a result of damages caused in part by the transport of cobble- and gravel-sized bed material. An investigation of the problem at low-water crossings was made by the U.S. Geological Survey in cooperation with the Texas Department of Transportation, and in collaboration with Texas Tech University, Lamar University, and the University of Houston. The bed-material entrainment problem for low-water crossings occurs at two spatial scales - watershed scale and channel-reach scale. First, the relative abundance and activity of cobble- and gravel-sized bed material along a given channel reach becomes greater with increasingly steeper watershed slopes. Second, the stresses required to mobilize bed material at a location can be attributed to reach-scale hydraulic factors, including channel geometry and particle size. The frequency of entrainment generally increases with downstream distance, as a result of decreasing particle size and increased flood magnitudes. An average of 1 year occurs between flows that initially entrain bed material as large as the median particle size, and an average of 1.5 years occurs between flows that completely entrain bed material as large as the median particle size. The Froude numbers associated with initial and complete entrainment of bed material up to the median particle size approximately are 0.40 and 0.45, respectively.

  19. Crystallization of synthetic coal-petcoke slag mixtures simulating those encountered in entrained bed slagging gasifiers

    SciTech Connect

    Jinichiro Nakano; Seetharaman Sridhar; Tyler Moss; James Bennett; Kyei-Sing Kwong

    2009-09-15

    Commercial entrained bed slagging gasifiers use a carbon feedstock of coal, petcoke, or combinations of them to produce CO and H{sub 2}. These carbon sources contain mineral impurities that liquefy during gasification and flow down the gasification sidewall, interacting with the refractory linear and solidifying in the cooler zones of the gasifier. Proper slag flow is critical to good gasifier operation. A hot-stage confocal scanning laser microscope (CSLM) was used to analyze the kinetic behavior of slag crystallization for a range of synthetic coal-petcoke mixtures. On the basis of the observed precipitation during cool down studies in the 1200-1700{sup o}C temperature range, a time-temperature-transformation (TTT) diagram was created. The crystallization studies were conducted with a CO/CO{sub 2} (=1.8) corresponding to a gasification PO{sub 2} of approximately 10-8 atm at 1500{sup o}C. Ash chemistries were chosen such that they correspond to coal-petcoke feedstock mixtures with coal ash amounts of 0, 10, 30, 50, 70, and 100% (by weight), with the balance being petcoke ash. The TTT diagram exhibited two crystallization areas, one above and one below 1350{sup o}C. At the nose of the higher temperature curves, karelianite (V{sub 2}O{sub 3}) crystallization occurred and was fastest for a 30% coal-petcoke ash mixture. The second nose was located below 1350{sup o}C and had spinel-type phases that formed at 1200{sup o}C, in which preferred atomic occupation at the octahedral and tetrahedral sites varied depending upon the ash composition. At 1200{sup o}C, an Al-rich spinel formed for 100% coal slag and a Fe-rich spinel formed in petcoke-enriched slags. The addition of petcoke ash to coal ash promoted crystallization in the slag, with additional crystalline phases, such as V-rich spinel, forming at the lower temperatures. These phases were not predicted using commercially available databases. 30 refs., 18 figs.

  20. The Role of High-Level Processes for Oscillatory Phase Entrainment to Speech Sound.

    PubMed

    Zoefel, Benedikt; VanRullen, Rufin

    2015-01-01

    Constantly bombarded with input, the brain has the need to filter out relevant information while ignoring the irrelevant rest. A powerful tool may be represented by neural oscillations which entrain their high-excitability phase to important input while their low-excitability phase attenuates irrelevant information. Indeed, the alignment between brain oscillations and speech improves intelligibility and helps dissociating speakers during a "cocktail party". Although well-investigated, the contribution of low- and high-level processes to phase entrainment to speech sound has only recently begun to be understood. Here, we review those findings, and concentrate on three main results: (1) Phase entrainment to speech sound is modulated by attention or predictions, likely supported by top-down signals and indicating higher-level processes involved in the brain's adjustment to speech. (2) As phase entrainment to speech can be observed without systematic fluctuations in sound amplitude or spectral content, it does not only reflect a passive steady-state "ringing" of the cochlea, but entails a higher-level process. (3) The role of intelligibility for phase entrainment is debated. Recent results suggest that intelligibility modulates the behavioral consequences of entrainment, rather than directly affecting the strength of entrainment in auditory regions. We conclude that phase entrainment to speech reflects a sophisticated mechanism: several high-level processes interact to optimally align neural oscillations with predicted events of high relevance, even when they are hidden in a continuous stream of background noise. PMID:26696863

  1. The Role of High-Level Processes for Oscillatory Phase Entrainment to Speech Sound

    PubMed Central

    Zoefel, Benedikt; VanRullen, Rufin

    2015-01-01

    Constantly bombarded with input, the brain has the need to filter out relevant information while ignoring the irrelevant rest. A powerful tool may be represented by neural oscillations which entrain their high-excitability phase to important input while their low-excitability phase attenuates irrelevant information. Indeed, the alignment between brain oscillations and speech improves intelligibility and helps dissociating speakers during a “cocktail party”. Although well-investigated, the contribution of low- and high-level processes to phase entrainment to speech sound has only recently begun to be understood. Here, we review those findings, and concentrate on three main results: (1) Phase entrainment to speech sound is modulated by attention or predictions, likely supported by top-down signals and indicating higher-level processes involved in the brain’s adjustment to speech. (2) As phase entrainment to speech can be observed without systematic fluctuations in sound amplitude or spectral content, it does not only reflect a passive steady-state “ringing” of the cochlea, but entails a higher-level process. (3) The role of intelligibility for phase entrainment is debated. Recent results suggest that intelligibility modulates the behavioral consequences of entrainment, rather than directly affecting the strength of entrainment in auditory regions. We conclude that phase entrainment to speech reflects a sophisticated mechanism: several high-level processes interact to optimally align neural oscillations with predicted events of high relevance, even when they are hidden in a continuous stream of background noise. PMID:26696863

  2. Entrainment of bed material by Earth-surface mass flows: review and reformulation of depth-integrated theory

    USGS Publications Warehouse

    Iverson, Richard M.; Chaojun Ouyang,

    2015-01-01

    Earth-surface mass flows such as debris flows, rock avalanches, and dam-break floods can grow greatly in size and destructive potential by entraining bed material they encounter. Increasing use of depth-integrated mass- and momentum-conservation equations to model these erosive flows motivates a review of the underlying theory. Our review indicates that many existing models apply depth-integrated conservation principles incorrectly, leading to spurious inferences about the role of mass and momentum exchanges at flow-bed boundaries. Model discrepancies can be rectified by analyzing conservation of mass and momentum in a two-layer system consisting of a moving upper layer and static lower layer. Our analysis shows that erosion or deposition rates at the interface between layers must in general satisfy three jump conditions. These conditions impose constraints on valid erosion formulas, and they help determine the correct forms of depth-integrated conservation equations. Two of the three jump conditions are closely analogous to Rankine-Hugoniot conditions that describe the behavior of shocks in compressible gasses, and the third jump condition describes shear traction discontinuities that necessarily exist across eroding boundaries. Grain-fluid mixtures commonly behave as compressible materials as they undergo entrainment, because changes in bulk density occur as the mixtures mobilize and merge with an overriding flow. If no bulk density change occurs, then only the shear-traction jump condition applies. Even for this special case, however, accurate formulation of depth-integrated momentum equations requires a clear distinction between boundary shear tractions that exist in the presence or absence of bed erosion.

  3. Apparatus and process for controlling fluidized beds

    DOEpatents

    Rehmat, Amirali G.; Patel, Jitendra G.

    1985-10-01

    An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

  4. Modeling and Experimental Studies of Mercury Oxidation and Adsorption in a Fixed-Bed and Entrained-Flow Reactor

    SciTech Connect

    Buitrago, Paula A.; Morrill, Mike; Lighty, JoAnn S.; Silcox, Geoffrey D.

    2009-06-01

    This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150°C. All methane, air, SO2, and halogen species were introduced through the burner to produce a radical pool representative of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150°C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO2, and NO2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and

  5. Modeling of fluidized bed silicon deposition process

    NASA Technical Reports Server (NTRS)

    Kim, K.; Hsu, G.; Lutwack, R.; PRATURI A. K.

    1977-01-01

    The model is intended for use as a means of improving fluidized bed reactor design and for the formulation of the research program in support of the contracts of Silicon Material Task for the development of the fluidized bed silicon deposition process. A computer program derived from the simple modeling is also described. Results of some sample calculations using the computer program are shown.

  6. A time-variant processing approach for the analysis of alpha and gamma MEG oscillations during flicker stimulus generated entrainment.

    PubMed

    Wacker, Matthias; Galicki, Miroslav; Putsche, Peter; Milde, Thomas; Schwab, Karin; Haueisen, Jens; Ligges, Carolin; Witte, Herbert

    2011-11-01

    Repetitive flicker stimulation (photic driving) offers the possibility to study the properties and coupling characteristics of stimulation-sensitive neuronal oscillators by means of the MEG/EEG analysis. With flicker frequencies in the region of the individual alpha band frequency, the dynamics of the entrainment process of the alpha oscillation, as well as the dynamics of the accompanying gamma oscillations and the coupling between the oscillations, are investigated by means of an appropriate combination of time-variant analysis methods. The Hilbert and the Gabor transformation reveal time-variant properties (frequency entrainment, phase locking, and n:m synchronization) of the entrainment process in the whole frequency range. Additionally, time-variant partial directed coherence is applied to identify ocular saccadic interferences and to study the directed information transfer between the recording sites of the simultaneously derived MEG/EEG data during the entrainment. The MEG data is the focus of this methodological study as the entrainment effects of the alpha oscillation are stronger in MEG than in the EEG. The occipital brain region (visual cortex) was mainly investigated and the dynamics of the alpha entrainment quantified. It can be shown that at the beginning of this entrainment, a transient, strongly phase-locked "40-Hz" gamma oscillation occurs. PMID:21712153

  7. Fluid-bed reaction process

    SciTech Connect

    Harandi, M.N.; Owen, H.

    1990-05-29

    This patent describes a process for the conversion of hydrocarbons. It comprises: fluidizing a finely divided dehydrogenation catalyst in a dehydrogenation reaction zone; withdrawing spent dehydrogenation catalyst from the dehydrogenation reaction zone; contacting an aliphatic feedstream with the spent dehydrogenation catalyst in a preheat zone to preheat the aliphatic feedstream and to convert at least a portion of the coke precursors in the aliphatic feedstream to coke; and depositing the coke on the spent dehydrogenation catalyst in the preheat zone.

  8. Observing Entrainment Processes Using a Small Unmanned Aerial Vehicle: A Feasibility Study

    NASA Astrophysics Data System (ADS)

    Martin, Sabrina; Beyrich, Frank; Bange, Jens

    2014-03-01

    Measurement flights with the meteorological mini aerial vehicle (MAV) were performed in spring 2011 to assess the capability of an unmanned aerial vehicle (UAV) to measure the structure of the transition zone between the convective boundary layer and the stably stratified free atmosphere. The campaign took place at the Meteorological Observatory Lindenberg/Richard-Aßmann-Observatory of the German Meteorological Service. Besides the MAV flights, observations were made from a 12-m and a 99-m tower, a sodar, two ceilometers, radiosondes, and a tethered balloon with sensor packages at six different levels. MAV measurements were intentionally combined with remote sensing systems. The height range of the entrainment zone as well as its diurnal cycle were provided by the remote sensing instruments. The UAV provided the high-resolution in situ data of temperature and wind for the study of turbulent processes. It is shown that the MAV is able to maintain constant altitude with very small deviations—a pre-requisite to study processes inside the often quite thin entrainment zone and that MAV high-resolution wind and temperature measurements allow for very detailed studies of the fine structure of the atmosphere and thus for the identification of quite local and/or short-duration processes such as overshooting thermals or downward intrusions of warm air. Spatial series measured by the MAV during horizontal flights show turbulent exchange of heat in short turbulent bursts at heights close to and within the entrainment zone. Scaled vertical profiles of vertical velocity, potential temperature variance, and sensible heat flux confirm the general shape found by previous measurements and numerical studies.

  9. Process for coal liquefaction by separation of entrained gases from slurry exiting staged dissolvers

    DOEpatents

    Givens, Edwin N.; Ying, David H. S.

    1983-01-01

    There is described an improved liquefaction process by which coal is converted to a low ash and low sulfur carbonaceous material that can be used as a fuel in an environmentally acceptable manner without costly gas scrubbing equipment. In the process, coal is slurried with a solvent, passed through a preheater and at least two dissolvers in series in the presence of hydrogen-rich gases at elevated temperatures and pressures. Solids, including mineral ash and unconverted coal macerals are separated from the condensed dissolver effluent. In accordance with the improved process, fresh hydrogen is fed to each dissolver and the entrained gas from each dissolver is separated from the slurry phase and removed from the reactor system before the condensed phase is passed to the next dissolver in the series. In accordance with another process, the feeds to the dissolvers are such that the top of each downstream dissolver is used as a gas-liquid separator.

  10. Measurement of powder bed density in powder bed fusion additive manufacturing processes

    NASA Astrophysics Data System (ADS)

    Jacob, G.; Donmez, A.; Slotwinski, J.; Moylan, S.

    2016-11-01

    Many factors influence the performance of additive manufacturing (AM) processes, resulting in a high degree of variation in process outcomes. Therefore, quantifying these factors and their correlations to process outcomes are important challenges to overcome to enable widespread adoption of emerging AM technologies. In the powder bed fusion AM process, the density of the powder layers in the powder bed is a key influencing factor. This paper introduces a method to determine the powder bed density (PBD) during the powder bed fusion (PBF) process. A complete uncertainty analysis associated with the measurement method was also described. The resulting expanded measurement uncertainty, U PBD (k  =  2), was determined as 0.004 g · cm‑3. It was shown that this expanded measurement uncertainty is about three orders of magnitude smaller than the typical powder bed density. This method enables establishing correlations between the changes in PBD and the direction of motion of the powder recoating arm.

  11. Fluidized bed heating process and apparatus

    NASA Technical Reports Server (NTRS)

    McHale, Edward J. (Inventor)

    1981-01-01

    Capacitive electrical heating of a fluidized bed enables the individual solid particles within the bed to constitute the hottest portion thereof. This effect is achieved by applying an A. C. voltage potential between dielectric coated electrodes, one of which is advantageously the wall of the fluidized bed rejection zone, sufficient to create electrical currents in said particles so as to dissipate heat therein. In the decomposition of silane or halosilanes in a fluidized bed reaction zone, such heating enhances the desired deposition of silicon product on the surface of the seed particles within the fluidized bed and minimizes undesired coating of silicon on the wall of the reaction zone and the homogeneous formation of fine silicon powder within said zone.

  12. Fluidized bed catalytic coal gasification process

    DOEpatents

    Euker, Jr., Charles A.; Wesselhoft, Robert D.; Dunkleman, John J.; Aquino, Dolores C.; Gouker, Toby R.

    1984-01-01

    Coal or similar carbonaceous solids impregnated with gasification catalyst constituents (16) are oxidized by contact with a gas containing between 2 volume percent and 21 volume percent oxygen at a temperature between 50.degree. C. and 250.degree. C. in an oxidation zone (24) and the resultant oxidized, catalyst impregnated solids are then gasified in a fluidized bed gasification zone (44) at an elevated pressure. The oxidation of the catalyst impregnated solids under these conditions insures that the bed density in the fluidized bed gasification zone will be relatively high even though the solids are gasified at elevated pressure and temperature.

  13. Landslide boost from entrainment of erodible material along the slope

    NASA Astrophysics Data System (ADS)

    Farin, M.; Mangeney, A.; Roche, O.; Ionescu, I.; Hungr, O.

    2011-12-01

    Landslides, debris flows, pyroclastic flows and avalanches are natural hazards that threaten life and property in mountainous, volcanic, coastal and seismically active areas. The granular mass tends to accelerate as gravity pulls it down the slope, and will slow on more gentle slopes, when interaction forces dissipating energy overcome the driving forces. The entrainment of underlying sediments or debris into the gravitational granular flows is suspected to be critical to their dynamics, but direct measurement of material entrainment in natural flows is very difficult. Nevertheless, qualitative and quantitative field observations suggest that material entrainment can either increase or decrease flow velocity and deposit extent, depending on the geological setting and the type of gravitational flow. Based on laboratory experiments on dry granular flows, we show here that erosion of granular material already present on the bed can significantly increase the size and mobility of the flow and possibly generate surges. We present laboratory experiments of granular material flowing over an inclined plane covered by an erodible bed, designed to mimic erosion processes of natural flows traveling over deposits built up by earlier events. The controlling parameters are the inclination of the plane and the thickness of the erodible layer. Different methods are used to prepare the erodible bed, thus leading to various degrees of compaction. We show that erosion processes increases the flow mobility (i. e. runout) by up to 40 % over slopes with inclination close to the repose angle of the grains. The effect is observed even for very thin erodible beds. We demonstrate that the increase of mass of the flowing grains caused by entrainment of the erodible layer is not enough to explain the observed increase in velocity and runout of the granular mass. Erosion efficiency is shown to strongly depend on the slope and on the nature (i. e. degree of compaction) of the erodible bed

  14. Air Entraining Flows

    NASA Astrophysics Data System (ADS)

    Prosperetti, Andrea

    2001-11-01

    Air entraining flows are frequently encountered in Nature (e.g. breaking waves, waterfalls, rain over water bodies) and in technological applications (gas-liquid chemical reactors, water treatment, aquaculture, and others). Superficially, one may distinguish between transient events, such as a breaking wave, and steady situations, e.g. a falling jet. However, when viscosity is not important, the process of air entrainment turns out to be the consequence of local transient events even in steady flows. For example, surface disturbances convected by a nominally steady jet impact the receiving liquid, create a deep depression, which collapses entraining an air pocket. (In practice this basic mechanism is complicated by the presence of waves, vortical flows, and other factors.) This talk will describe several examples of air-entraining flows illustrating the fluid mechanic principles involved with high-speed movies and numerical computations.

  15. Process wastewater treatability study for Westinghouse fluidized-bed coal gasification

    SciTech Connect

    Winton, S.L.; Buvinger, B.J.; Evans, J.M.; French, W.E.; Page, G.C.; Rhodes, W.J.

    1983-11-01

    In the development of a synthetic fuels facility, water usage and wastewater treatment are major areas of concern. Coal gasification processes generally produce relatively large volumes of gas condensates. These wastewaters are typically composed of a variety of suspended and dissolved organic and inorganic solids and dissolved gaseous contaminants. Fluidized-bed coal gasification (FBG) processes are no exception to this rule. The Department of Energy's Morgantown Energy Technology Center (METC), the Gas Research Institute (GRI), and the Environmental Protection Agency (EPA/IERLRTP) recognized the need for a FBG treatment program to provide process design data for FBG wastewaters during the environmental, health, and safety characterization of the Westinghouse Process Development Unit (PDU). In response to this need, METC developed conceptual designs and a program plan to obtain process design and performance data for treating wastewater from commercial-scale Westinghouse-based synfuels plants. As a result of this plan, METC, GRI, and EPA entered into a joint program to develop performance data, design parameters, conceptual designs, and cost estimates for treating wastewaters from a FBG plant. Wastewater from the Westinghouse PDU consists of process quench and gas cooling condensates which are similar to those produced by other FBG processes such as U-Gas, and entrained-bed gasification processes such as Texaco. Therefore, wastewater from this facility was selected as the basis for this study. This paper outlines the current program for developing process design and cost data for the treatment of these wastewaters.

  16. Development of an advanced process for drying fine coal in an inclined fluidized bed

    SciTech Connect

    Boysen, J.E.; Cha, C.Y.; Barbour, F.A.; Turner, T.F.; Kang, T.W.; Berggren, M.H.; Hogsett, R.F.; Jha, M.C.

    1990-02-01

    The objective of this research project was to demonstrate a technically feasible and economically viable process for drying and stabilizing high-moisture subbituminous coal. Controlled thermal drying of coal fines was achieved using the inclined fluidized-bed drying and stabilization process developed by the Western Research Institute. The project scope of work required completion of five tasks: (1) project planning, (2) characterization of two feed coals, (3) bench-scale inclined fluidized-bed drying studies, (4) product characterization and testing, and (5) technical and economic evaluation of the process. High moisture subbituminous coals from AMAX Eagle Butte mine located in the Powder River Basin of Wyoming and from Usibelli Coal Mine, Inc. in Healy, Alaska were tested in a 10-lb/hr bench-scale inclined fluidized-bed. Experimental results show that the dried coal contains less than 1.5% moisture and has a heating value over 11,500 Btu/lb. The coal fines entrainment can be kept below 15 wt % of the feed. The equilibrium moisture of dried coal was less than 50% of feed coal equilibrium moisture. 7 refs., 60 figs., 47 tabs.

  17. Processes limiting mussel bed restoration in the Wadden-Sea

    NASA Astrophysics Data System (ADS)

    de Paoli, Hélène; van de Koppel, Johan; van der Zee, Els; Kangeri, Arno; van Belzen, Jim; Holthuijsen, Sander; van den Berg, Aniek; Herman, Peter; Olff, Han; van der Heide, Tjisse

    2015-09-01

    This paper reports on experimental restoration of mussel beds in the Wadden Sea and the processes that might limit successful restoration of this foundation species (i.e. substrate, predation, hydrodynamics). The importance of substrate, predation, hydrodynamic conditions and location on mussel restoration success was studied using artificially created mussel beds. Experimental beds established on a stable substrate (coir net) were compared with control beds established on sand, at three locations in the Wadden Sea. Their persistence was followed over time. The results revealed a near disappearance of all experimental beds in just over 7 months. Providing a stable substrate did not improve mussel survival. Predation could not explain the disappearance of the beds, as the maximal predation rate by birds was found to be insufficient to have a significant effect on mussel cover. Differences in wave conditions alone could also not explain the variation in decline of mussel cover between the locations. However, the gradual disappearance of mussels from the seaward side of the bed strongly suggested that hydrodynamic conditions (i.e. combined effects of waves and current) played an important role in the poor persistence of the artificial beds. Our results highlight the fact that restoration of mussel beds in dynamic areas cannot simply be implemented by mussel transplantation, particularly if additional measures to prevent wave losses are not taken, even when artificial substrate is provided to facilitate mussel adhesion.

  18. Oil production by entrained pyrolysis of biomass and processing of oil and char

    DOEpatents

    Knight, James A.; Gorton, Charles W.

    1990-01-02

    Entrained pyrolysis of lignocellulosic material proceeds from a controlled pyrolysis-initiating temperature to completion of an oxygen free environment at atmospheric pressure and controlled residence time to provide a high yield recovery of pyrolysis oil together with char and non-condensable, combustible gases. The residence time is a function of gas flow rate and the initiating temperature is likewise a function of the gas flow rate, varying therewith. A controlled initiating temperature range of about 400.degree. C. to 550.degree. C. with corresponding gas flow rates to maximize oil yield is disclosed.

  19. Laboratory experiments investigating entrainment by debris flows and associated increased mobility

    NASA Astrophysics Data System (ADS)

    Moberly, D.; Maki, L.; Hill, K. M.

    2014-12-01

    As debris flows course down a steep hillside they entrain bed materials such as loose sediments. The entrainment of materials not only increases the size of the debris flows but the mobility as well. The mechanics underlying the particle entrainment and the associated increased mobility are not well-understood. Existing models for the entrainment process include those that explicitly consider stress ratios, the angle of inclination, and the particle fluxes relative to those achieved under steady conditions. Others include an explicit consideration of the physics of the granular state: the visco-elastic nature of particle flows and, alternatively, the role of macroscopic force chains. Understanding how well these different approaches account for entrainment and deposition rates is important for accurate debris flow modeling, both in terms of the rate of growth and also in terms of the increased mobility associated with the entrainment. We investigate how total and instantaneous entrainment and deposition vary with macroscopic stresses and particle-scale interactions for different particle sizes and different fluid contents using laboratory experiments in an instrumented experimental laboratory debris flow flume. The flume has separate, independent water supplies for the bed and "supply" (parent debris flow), and the bed is instrumented with pore pressure sensors and a basal stress transducer. We monitor flow velocities, local structure, and instantaneous entrainment and deposition rates using a high speed camera. We have found that systems with a mixture of particle sizes are less erosive and more depositional than systems of one particle size under otherwise the same conditions. For both mixtures and single-sized particle systems, we have observed a relatively linear relationship between total erosion and the slope angle for dry flows. Increasing fluid content typically increases entrainment. Measurements of instantaneous entrainment indicate similar dependencies

  20. Bubbling bed catalytic hydropyrolysis process utilizing larger catalyst particles and smaller biomass particles featuring an anti-slugging reactor

    DOEpatents

    Marker, Terry L; Felix, Larry G; Linck, Martin B; Roberts, Michael J

    2014-09-23

    This invention relates to a process for thermochemically transforming biomass or other oxygenated feedstocks into high quality liquid hydrocarbon fuels. In particular, a catalytic hydropyrolysis reactor, containing a deep bed of fluidized catalyst particles is utilized to accept particles of biomass or other oxygenated feedstocks that are significantly smaller than the particles of catalyst in the fluidized bed. The reactor features an insert or other structure disposed within the reactor vessel that inhibits slugging of the bed and thereby minimizes attrition of the catalyst. Within the bed, the biomass feedstock is converted into a vapor-phase product, containing hydrocarbon molecules and other process vapors, and an entrained solid char product, which is separated from the vapor stream after the vapor stream has been exhausted from the top of the reactor. When the product vapor stream is cooled to ambient temperatures, a significant proportion of the hydrocarbons in the product vapor stream can be recovered as a liquid stream of hydrophobic hydrocarbons, with properties consistent with those of gasoline, kerosene, and diesel fuel. Separate streams of gasoline, kerosene, and diesel fuel may also be obtained, either via selective condensation of each type of fuel, or via later distillation of the combined hydrocarbon liquid.

  1. A model for entrainment in avalanches and debris flows based on PIV measurements of viscous gravity currents

    NASA Astrophysics Data System (ADS)

    Bates, Belinda; Ancey, Christophe

    2014-05-01

    A simple experiment, designed to investigate entrainment in geophysical free-surface flows such as avalanches and debris flows, was performed using a dam break of viscous fluid which travels over a rigid bed until meeting a shallow layer of the same fluid at rest; this represents an avalanche which begins entraining material along its path. Particle image velocimetry (PIV) on a streamwise section in the entrainment zone allowed the measurement of internal flow velocities and the observation of entrainment processes such as bed excavation. Image processing techniques were used to identify surface height and the current/substrate interface. A model was derived for this system, starting from the viscous Navier-Stokes equations for conservation of mass and momentum in domains including entrainable material. The flow is shallow and there is a rigid base, b(x) below z=0, representing the beginning of an entrainable region (modelled by a hyperbolic tangent). The free-surface kinematic boundary condition was used to link surface height and flow velocity, thus removing the need for depth-averaging. The derived equations are solved using a parabolic solver to obtain the surface height and velocity field throughout the flow and the velocities are used in a simple advection scheme, examining the progression of the current/substrate interface at the base of the dam-break. The numerical predictions closely match the experimental observations. Sharp surface height gradients diffuse quickly upon entry into the entrainment zone and the flow front accelerates. The current sinks into the bed and downstream bed material is forced upwards as found in the laboratory. The rates that the current excavates the bed, both in the vertical and streamwise directions, follow the same power laws as observed, and the surface height and internal velocities are in agreement in the model and the experiments.

  2. Pulsed atmospheric fluidized bed combustor apparatus and process

    DOEpatents

    Mansour, Momtaz N.

    1992-01-01

    A pulsed atmospheric fluidized bed reactor system is disclosed and claimed along with a process for utilization of same for the combustion of, e.g. high sulfur content coal. The system affords a economical, ecologically acceptable alternative to oil and gas fired combustors. The apparatus may also be employed for endothermic reaction, combustion of waste products, e.g. organic and medical waste, drying, calcining and the like.

  3. Low-Frequency Cortical Entrainment to Speech Reflects Phoneme-Level Processing.

    PubMed

    Di Liberto, Giovanni M; O'Sullivan, James A; Lalor, Edmund C

    2015-10-01

    The human ability to understand speech is underpinned by a hierarchical auditory system whose successive stages process increasingly complex attributes of the acoustic input. It has been suggested that to produce categorical speech perception, this system must elicit consistent neural responses to speech tokens (e.g., phonemes) despite variations in their acoustics. Here, using electroencephalography (EEG), we provide evidence for this categorical phoneme-level speech processing by showing that the relationship between continuous speech and neural activity is best described when that speech is represented using both low-level spectrotemporal information and categorical labeling of phonetic features. Furthermore, the mapping between phonemes and EEG becomes more discriminative for phonetic features at longer latencies, in line with what one might expect from a hierarchical system. Importantly, these effects are not seen for time-reversed speech. These findings may form the basis for future research on natural language processing in specific cohorts of interest and for broader insights into how brains transform acoustic input into meaning. PMID:26412129

  4. Tracking cortical entrainment in neural activity: auditory processes in human temporal cortex

    PubMed Central

    Thwaites, Andrew; Nimmo-Smith, Ian; Fonteneau, Elisabeth; Patterson, Roy D.; Buttery, Paula; Marslen-Wilson, William D.

    2015-01-01

    A primary objective for cognitive neuroscience is to identify how features of the sensory environment are encoded in neural activity. Current auditory models of loudness perception can be used to make detailed predictions about the neural activity of the cortex as an individual listens to speech. We used two such models (loudness-sones and loudness-phons), varying in their psychophysiological realism, to predict the instantaneous loudness contours produced by 480 isolated words. These two sets of 480 contours were used to search for electrophysiological evidence of loudness processing in whole-brain recordings of electro- and magneto-encephalographic (EMEG) activity, recorded while subjects listened to the words. The technique identified a bilateral sequence of loudness processes, predicted by the more realistic loudness-sones model, that begin in auditory cortex at ~80 ms and subsequently reappear, tracking progressively down the superior temporal sulcus (STS) at lags from 230 to 330 ms. The technique was then extended to search for regions sensitive to the fundamental frequency (F0) of the voiced parts of the speech. It identified a bilateral F0 process in auditory cortex at a lag of ~90 ms, which was not followed by activity in STS. The results suggest that loudness information is being used to guide the analysis of the speech stream as it proceeds beyond auditory cortex down STS toward the temporal pole. PMID:25713530

  5. Enhanced Productivity of Chemical Processes Using Dense Fluidized Beds

    SciTech Connect

    Sibashis Banerjee; Alvin Chen; Rutton Patel; Dale Snider; Ken Williams; Timothy O'Hern; Paul Tortora

    2008-02-29

    The work detailed in this report addresses Enabling Technologies within Computational Technology by integrating a “breakthrough” particle-fluid computational technology into traditional Process Science and Engineering Technology. The work completed under this DOE project addresses five major development areas 1) gas chemistry in dense fluidized beds 2) thermal cracking of liquid film on solids producing gas products 3) liquid injection in a fluidized bed with particle-to-particle liquid film transport 4) solid-gas chemistry and 5) first level validation of models. Because of the nature of the research using tightly coupled solids and fluid phases with a Lagrangian description of the solids and continuum description of fluid, the work provides ground-breaking advances in reactor prediction capability. This capability has been tested against experimental data where available. The commercial product arising out of this work is called Barracuda and is suitable for a wide (dense-to-dilute) range of industrial scale gas-solid flows with and without reactions. Commercial applications include dense gas-solid beds, gasifiers, riser reactors and cyclones.

  6. Entrainment Rates in POST Stratocumulus

    NASA Astrophysics Data System (ADS)

    Gerber, H. E.; Frick, G.

    2010-12-01

    A recent field study (POST; Physics of Stratocumulus top; July-Aug., 2008) off the California Coast used the CIRPAS Twin Otter aircraft to observe mostly unbroken stratocumulus clouds (Sc). Seventeen flights were made in a quasi-Lagrangian horizontal pattern and in a vertical profiling pattern +/- 100 m about Sc top that was repeated numerous times. The aircraft carried a full complement of probes, including the high rate (1000-hz) UFT (ultra-fast temperature) and PVM (LWC and effective radius) probes both of which provided data within cloud and were located near the aircraft’s gust probe. The latter two probes were used to estimate the entrainment velocity (we) into the Sc using the “conditional sampling” approach. The range of we values fall within previous estimates of we, and examples of the measurements are presented. This we data set provides new insight on the entrainment process with findings including the following: About on half the POST flights the Sc showed entrainment behavior unlike that expected from previous applications of the “conditional sampling” method. Higher wind speeds and shear near Sc top generated significant turbulence both above and below the cloud-top interface causing the linear entrainment flux approximation near Sc top to be invalid. This behavior would also affect the “flux-jump” method used previously for estimating we., leading to questions about the validity of previous we measurements. In addition the required sharp jump at the interface of the entrainment scalar was not present in some cases. The “conditional sampling” method yields pdfs of the entrainment parcel length which are variable depending on the flight. The lengths are sufficiently large in some cases and are compatible with practical LES grid spacing suggesting a LES modeling and measurement comparison, where the more robust measurement is the entrainment flux into the POST Sc rather than the estimate of we.

  7. Entrainment in interacting vortex rings

    NASA Astrophysics Data System (ADS)

    Shami, Rammah; Ganapathisubramani, Bharathram

    2014-11-01

    The efficiency of entrainment in single vortex rings has been examined by various studies in the literature. These studies have shown that this efficiency is greatly increased for smaller stroke-time to nozzle-diameter ratios, L/D. However, no clear consensus exists regarding the effect on the entrainment process for the sectioned delivery of the vortex forming impulse. In the present work the entrainment mechanism associated with the interaction between two co-axially separated vortex rings is explored. Planar, time-resolved particle image velocimetry (PIV) measurements are taken of a interacting vortex flow field. Lagrangian coherent structures (LCS) extracted from the finite-time Lyapunov exponent (FTLE) fields are employed to determine the vortex boundaries of the interacting rings and is then used to measure entrainment. Preliminary results indicate that whilst the most efficient entrainment of ambient fluid by the ring pairs occurs at larger separations, the rate and overall mass transport increase can be controlled by altering the spatial/temporal separation between successive rings and is higher at smaller ring spacing. Variation in mass transport behaviour for different ring strengths (L/D) and Reynolds numbers will also be discussed.

  8. Process simulation of a circulating fluidized bed coal combustor

    SciTech Connect

    Legros, R.; Sotudeh-Gharebaagh, R.; Paris, J.; Chaouki, J.; Preto, F.

    1995-12-31

    The focus of this work is the development of a process simulator for a Circulating Fluidized Bed coal Combustor (CFBC). The development of a simple comprehensive model for coal combustion in a CFBC is based on existing work reported in the literature. The model combines the hydrodynamic features of a CFBC riser with the different reaction steps involved during coal combustion, including the sulphur capture by limestone particles. The commercial process simulation program ASPEN PLUS was chosen as a framework for the development of the CFBC process simulator. ASPEN PLUS has been widely accepted in the chemical industry as a design tool because of its ability to simulate various chemical processes, including power generation cycles. In ASPEN PLUS, several ideal chemical reactor models involving solids are available for simulation purposes. The CFBC process simulator is constructed using several ASPEN PLUS unit operation blocks. The information required for each block is obtained from the combustion and hydrodynamic models, which are inserted into the simulation flowsheet as subroutines or internal programs. The resulting CFBC process simulator is used to predict the performance of the CFBC pilot plant at Energy Research laboratories, CANMET in Ottawa.

  9. Application of ultrasonic backscattering for level measurement and process monitoring of expanded-bed adsorption columns.

    PubMed

    Thelen, T V; Mairal, A P; Thorsen, C S; Ramirez, W F

    1997-01-01

    Expanded-bed adsorption is a newly commercialized technique for the purification of proteins from cellular debris in downstream processing. An expanded bed presents the possibility of protein recovery in a single step, eliminating the often costly clarification processing steps such as ultrafiltration, centrifugation, and precipitation. A major obstacle to the successful commercialization of this technology is the inability to accurately monitor and control the bed height in these systems. Fluctuations in the feedstock viscosity are common during normal operation and tend to make the operation and control of expanded beds for biological applications complex and difficult. We develop a level measurement technique based upon ultrasonics. It is shown that this technique has great promise for bed-height measurement in expanded-bed adsorption systems. Furthermore, the bed-height measurement can be used in feedback control strategies for bed-height regulation. The proposed ultrasonic sensor is also capable of monitoring for plugging and bubbling in the column. PMID:9336988

  10. Innovations in wastewater treatment: the moving bed biofilm process.

    PubMed

    Odegaard, Hallvard

    2006-01-01

    This paper describes the moving bed biofilm reactor (MBBR) and presents applications of wastewater treatment processes in which this reactor is used. The MBBR processes have been extensively used for BOD/COD-removal, as well as for nitrification and denitrification in municipal and industrial wastewater treatment. This paper focuses on the municipal applications. The most frequent process combinations are presented and discussed. Basic design data obtained through research, as well as data from practical operation of various plants, are presented. It is demonstrated that the MBBR may be used in an extremely compact high-rate process (<1 h total HRT) for secondary treatment. Most European plants require P-removal and performance data from plants combining MBBR and chemical precipitation is presented. Likewise, data from plants in Italy and Switzerland that are implementing nitrification in addition to secondary treatment are presented. The results from three Norwegian plants that are using the so-called combined denitrification MBBR process are discussed. Nitrification rates as high as 1.2 g NH4-N/m2 d at complete nitrification were demonstrated in practical operation at low temperatures (11 degrees C), while denitrification rates were as high as 3.5g NO3-Nequiv./m2.d. Depending on the extent of pretreatment, the total HRT of the MBBR for N-removal will be in the range of 3 to 5 h. PMID:16841724

  11. Moving bed biofilm reactor technology: process applications, design, and performance.

    PubMed

    McQuarrie, James P; Boltz, Joshua P

    2011-06-01

    The moving bed biofilm reactor (MBBR) can operate as a 2- (anoxic) or 3-(aerobic) phase system with buoyant free-moving plastic biofilm carriers. These systems can be used for municipal and industrial wastewater treatment, aquaculture, potable water denitrification, and, in roughing, secondary, tertiary, and sidestream applications. The system includes a submerged biofilm reactor and liquid-solids separation unit. The MBBR process benefits include the following: (1) capacity to meet treatment objectives similar to activated sludge systems with respect to carbon-oxidation and nitrogen removal, but requires a smaller tank volume than a clarifier-coupled activated sludge system; (2) biomass retention is clarifier-independent and solids loading to the liquid-solids separation unit is reduced significantly when compared with activated sludge systems; (3) the MBBR is a continuous-flow process that does not require a special operational cycle for biofilm thickness, L(F), control (e.g., biologically active filter backwashing); and (4) liquid-solids separation can be achieved with a variety of processes, including conventional and compact high-rate processes. Information related to system design is fragmented and poorly documented. This paper seeks to address this issue by summarizing state-of-the art MBBR design procedures and providing the reader with an overview of some commercially available systems and their components. PMID:21751715

  12. Moving bed biofilm reactor technology: process applications, design, and performance.

    PubMed

    McQuarrie, James P; Boltz, Joshua P

    2011-06-01

    The moving bed biofilm reactor (MBBR) can operate as a 2- (anoxic) or 3-(aerobic) phase system with buoyant free-moving plastic biofilm carriers. These systems can be used for municipal and industrial wastewater treatment, aquaculture, potable water denitrification, and, in roughing, secondary, tertiary, and sidestream applications. The system includes a submerged biofilm reactor and liquid-solids separation unit. The MBBR process benefits include the following: (1) capacity to meet treatment objectives similar to activated sludge systems with respect to carbon-oxidation and nitrogen removal, but requires a smaller tank volume than a clarifier-coupled activated sludge system; (2) biomass retention is clarifier-independent and solids loading to the liquid-solids separation unit is reduced significantly when compared with activated sludge systems; (3) the MBBR is a continuous-flow process that does not require a special operational cycle for biofilm thickness, L(F), control (e.g., biologically active filter backwashing); and (4) liquid-solids separation can be achieved with a variety of processes, including conventional and compact high-rate processes. Information related to system design is fragmented and poorly documented. This paper seeks to address this issue by summarizing state-of-the art MBBR design procedures and providing the reader with an overview of some commercially available systems and their components.

  13. Bed occupancy monitoring: data processing and clinician user interface design.

    PubMed

    Pouliot, Melanie; Joshi, Vilas; Goubran, Rafik; Knoefel, Frank

    2012-01-01

    Unobtrusive and continuous monitoring of patients, especially at their place of residence, is becoming a significant part of the healthcare model. A variety of sensors are being used to monitor different patient conditions. Bed occupancy monitoring provides clinicians a quantitative measure of bed entry/exit patterns and may provide information relating to sleep quality. This paper presents a bed occupancy monitoring system using a bed pressure mat sensor. A clinical trial was performed involving 8 patients to collect bed occupancy data. The trial period for each patient ranged from 5-10 weeks. This data was analyzed using a participatory design methodology incorporating clinician feedback to obtain bed occupancy parameters. The parameters extracted include the number of bed exits per night, the bed exit weekly average (including minimum and maximum), the time of day of a particular exit, and the amount of uninterrupted bed occupancy per night. The design of a clinical user interface plays a significant role in the acceptance of such patient monitoring systems by clinicians. The clinician user interface proposed in this paper was designed to be intuitive, easy to navigate and not cause information overload. An iterative design methodology was used for the interface design. The interface design is extendible to incorporate data from multiple sensors. This allows the interface to be part of a comprehensive remote patient monitoring system.

  14. Entrainment Rate in Shallow Cumuli: Dependence on Entrained Dry Air Sources and Probability Density Functions

    NASA Astrophysics Data System (ADS)

    Lu, C.; Liu, Y.; Niu, S.; Vogelmann, A. M.

    2012-12-01

    In situ aircraft cumulus observations from the RACORO field campaign are used to estimate entrainment rate for individual clouds using a recently developed mixing fraction approach. The entrainment rate is computed based on the observed state of the cloud core and the state of the air that is laterally mixed into the cloud at its edge. The computed entrainment rate decreases when the air is entrained from increasing distance from the cloud core edge; this is because the air farther away from cloud edge is drier than the neighboring air that is within the humid shells around cumulus clouds. Probability density functions of entrainment rate are well fitted by lognormal distributions at different heights above cloud base for different dry air sources (i.e., different source distances from the cloud core edge). Such lognormal distribution functions are appropriate for inclusion into future entrainment rate parameterization in large scale models. To the authors' knowledge, this is the first time that probability density functions of entrainment rate have been obtained in shallow cumulus clouds based on in situ observations. The reason for the wide spread of entrainment rate is that the observed clouds are affected by entrainment mixing processes to different extents, which is verified by the relationships between the entrainment rate and cloud microphysics/dynamics. The entrainment rate is negatively correlated with liquid water content and cloud droplet number concentration due to the dilution and evaporation in entrainment mixing processes. The entrainment rate is positively correlated with relative dispersion (i.e., ratio of standard deviation to mean value) of liquid water content and droplet size distributions, consistent with the theoretical expectation that entrainment mixing processes are responsible for microphysics fluctuations and spectral broadening. The entrainment rate is negatively correlated with vertical velocity and dissipation rate because entrainment

  15. Prediction and measurement of entrained flow coal gasification processes. Interim report, September 8, 1981-September 7, 1983

    SciTech Connect

    Hedman, P.O.; Smoot, L.D.; Fletcher, T.H.; Smith, P.J.; Blackham, A.U.

    1984-01-31

    This volume reports interim experimental and theoretical results of the first two years of a three year study of entrained coal gasification with steam and oxygen. The gasifier facility and testing methods were revised and improved. The gasifier was also modified for high pressure operation. Six successful check-out tests at elevated pressure were performed (55, 75, 100, 130, 170, and 215 psig), and 8 successful mapping tests were performed with the Utah bituminous coal at an elevated pressure of 137.5 psig. Also, mapping tests were performed at atmospheric pressure with a Utah bituminous coal (9 tests) and with a Wyoming subbituminous coal (14 tests). The LDV system was used on the cold-flow facility to make additional nonreactive jets mixing measurements (local mean and turbulent velocity) that could be used to help validate the two-dimensional code. The previously completed two-dimensional entrained coal gasification code, PCGC-2, was evaluated through rigorous comparison with cold-flow, pulverized coal combustion, and entrained coal gasification data. Data from this laboratory were primarily used but data from other laboratories were used when available. A complete set of the data used has been compiled into a Data Book which is included as a supplemental volume of this interim report. A revised user's manual for the two-dimensional code has been prepared and is also included as a part of this interim report. Three technical papers based on the results of this study were published or prepared. 107 references, 57 figures, 35 tables.

  16. Observational constraints on entrainment in stratocumulus

    NASA Astrophysics Data System (ADS)

    Chuang, P. Y.; Carman, J. K.; Rossiter, D. L.; Khelif, D.; Jonsson, H.; Faloona, I. C.

    2012-12-01

    Aircraft sampling of the stratocumulus-topped boundary layer (STBL) during the Physics of Stratocumulus Top (POST) experiment was primarily achieved using sawtooth flight patterns, during which the atmospheric layer 100 m above and below cloud top was sampled at a frequency of once every 2 min. The large data set that resulted from each of the 16 flights document the complex vertical structure and variability of this interfacial region. In this study, we utilize the POST data to shed light on and constrain processes relevant to entrainment. We define "entrainment efficiency" as the ratio of the turbulent kinetic energy consumed by entrainment to that generated within the STBL (primarily by cloud-top cooling). We find values for the entrainment efficiency that vary by 1.5 orders of magnitude, which is even greater than the one order-of-magnitude that previous modeling results have suggested. Our analysis also demonstrates that the entrainment efficiency depends on the strength of the stratification across the entrainment interface layer, but not on the strength of turbulence in the cloud top region. The relationships between entrainment efficiency and other STBL parameters serve as novel observational contraints for simulations of entrainment in such systems.

  17. Avoiding Carbon Bed Hot Spots in Thermal Process Off-Gas Systems

    SciTech Connect

    Nick Soelberg; Joe Enneking

    2011-05-01

    Mercury has had various uses in nuclear fuel reprocessing and other nuclear processes, and so is often present in radioactive and mixed (radioactive and hazardous) wastes. Test programs performed in recent years have shown that mercury in off-gas streams from processes that treat radioactive wastes can be controlled using fixed beds of activated sulfur-impregnated carbon, to levels low enough to comply with air emission regulations such as the Hazardous Waste Combustor (HWC) Maximum Achievable Control Technology (MACT) standards. Carbon bed hot spots or fires have occurred several times during these tests, and also during a remediation of tanks that contained mixed waste. Hot spots occur when localized areas in a carbon bed become heated to temperatures where oxidation occurs. This heating typically occurs due to heat of absoption of gas species onto the carbon, but it can also be caused through external means such as external heaters used to heat the carbon bed vessel. Hot spots, if not promptly mitigated, can grow into bed fires. Carbon bed hot spots and fires must be avoided in processes that treat radioactive and mixed waste. Hot spots are detected by (a) monitoring in-bed and bed outlet gas temperatures, and (b) more important, monitoring of bed outlet gas CO concentrations. Hot spots are mitigated by (a) designing for appropriate in-bed gas velocity, for avoiding gas flow maldistribution, and for sufficient but not excessive bed depth, (b) appropriate monitoring and control of gas and bed temperatures and compositions, and (c) prompt implementation of corrective actions if bed hot spots are detected. Corrective actions must be implemented quickly if bed hot spots are detected, using a graded approach and sequence starting with corrective actions that are simple, quick, cause the least impact to the process, and are easiest to recover from.

  18. Granular motions near the threshold of entrainment

    NASA Astrophysics Data System (ADS)

    Valyrakis, Manousos; Alexakis, athanasios-Theodosios

    2016-04-01

    Our society is continuously impacted by significant weather events many times resulting in catastrophes that interrupt our normal way of life. In the context of climate change and increasing urbanisation these "extreme" hydrologic events are intensified both in magnitude and frequency, inducing costs of the order of billions of pounds. The vast majority of such costs and impacts (even more to developed societies) are due to water related catastrophes such as the geomorphic action of flowing water (including scouring of critical infrastructure, bed and bank destabilisation) and flooding. New tools and radically novel concepts are in need, to enable our society becoming more resilient. This presentation, emphasises the utility of inertial sensors in gaining new insights on the interaction of flow hydrodynamics with the granular surface at the particle scale and for near threshold flow conditions. In particular, new designs of the "smart-sphere" device are discussed with focus on the purpose specific sets of flume experiments, designed to identify the exact response of the particle resting at the bed surface for various below, near and above threshold flow conditions. New sets of measurements are presented for particle entrainment from a Lagrangian viewpoint. Further to finding direct application in addressing real world challenges in the water sector, it is shown that such novel sensor systems can also help the research community (both experimentalists and computational modellers) gain a better insight on the underlying processes governing granular dynamics.

  19. Prediction and measurement of optimum operating conditions for entrained coal gasification processes. Quarterly technical progress report, No. 1, 1 November 1979-31 January 1980

    SciTech Connect

    Smoot, L.D.; Hedman, P.O.; Smith, P.J.

    1980-02-15

    This report summarizes work completed to predict and measure optimum operating conditions for entrained coal gasifications processes. This study is the third in a series designed to investigate mixing and reaction in entrained coal gasifiers. A new team of graduate and undergraduate students was formed to conduct the experiments on optimum gasification operating conditions. Additional coal types, which will be tested in the gasifier were identified, ordered, and delivered. Characterization of these coals will be initiated. Hardware design modifications to introduce swirl into the secondary were initiated. Minor modifications were made to the gasifier to allow laser diagnostics to be made on an independently funded study with the Los Alamos Scientific Laboratory. The tasks completed on the two-dimensional model included the substantiation of a Gaussian PDF for the top-hat PDF in BURN and the completion of a Lagrangian particle turbulent dispersion module. The reacting submodel is progressing into the final stages of debug. The formulation of the radiation submodel is nearly complete and coding has been initiated. A device was designed, fabricated, and used to calibrate the actual Swirl Number of the cold-flow swirl generator used in the Phase 2 study. Swirl calibrations were obtained at the normal tests flow rates and at reduced flow rates. Two cold-flow tests were also performed to gather local velocity data under swirling conditions. Further analysis of the cold-flow coal-dust and swirl test results from the previous Phase 2 study were completed.

  20. Process analytical tools for monitoring, understanding, and control of pharmaceutical fluidized bed granulation: A review.

    PubMed

    Burggraeve, Anneleen; Monteyne, Tinne; Vervaet, Chris; Remon, Jean Paul; De Beer, Thomas

    2013-01-01

    Fluidized bed granulation is a widely applied wet granulation technique in the pharmaceutical industry to produce solid dosage forms. The process involves the spraying of a binder liquid onto fluidizing powder particles. As a result, the (wetted) particles collide with each other and form larger permanent aggregates (granules). After spraying the required amount of granulation liquid, the wet granules are rapidly dried in the fluid bed granulator. Since the FDA launched its Process Analytical Technology initiative (and even before), a wide range of analytical process sensors has been used for real-time monitoring and control of fluid bed granulation processes. By applying various data analysis techniques to the multitude of data collected from the process analyzers implemented in fluid bed granulators, a deeper understanding of the process has been achieved. This review gives an overview of the process analytical technologies used during fluid bed granulation to monitor and control the process. The fundamentals of the mechanisms contributing to wet granule growth and the characteristics of fluid bed granulation processing are briefly discussed. This is followed by a detailed overview of the in-line applied process analyzers, contributing to improved fluid bed granulation understanding, modeling, control, and endpoint detection. Analysis and modeling tools enabling the extraction of the relevant information from the complex data collected during granulation and the control of the process are highlighted.

  1. Fluidized-bed bioreactor process for the microbial solubiliztion of coal

    DOEpatents

    Scott, Charles D.; Strandberg, Gerald W.

    1989-01-01

    A fluidized-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fluidized-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fluidized-bed bioreactor.

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

    NASA Technical Reports Server (NTRS)

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

    1967-01-01

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

  3. Basal entrainment by Newtonian gravity-driven flows

    NASA Astrophysics Data System (ADS)

    Bates, Belinda; Andreini, Nicolas; Ancey, Christophe

    2016-04-01

    Gravity-driven flows can erode the bed along which they descend and increase their mass by a factor of 10 or more. This process is called basal entrainment. Although documented by field observations and laboratory experiments, it remains poorly understood. We look into this issue by studying eroding dam-break waves. More specifically we would like to determine what happens when a viscous gravity-driven flow generated by releasing a fixed volume of incompressible Newtonian fluid encounters a stationary erodible layer (composed of fluid with the same density and viscosity). Models based on depth-averaged mass and momentum balance equations deal with bed-flow interfaces as shock waves. In contrast, we use an approach involving the long-wave approximation of the Navier-Stokes equations (lubrication theory), and in this context, bed-flow interfaces are acceleration waves that move quickly across thin stationary layers. The incoming flow digs down into the bed, pushing up downstream material, thus advancing the flow front. Extending the method used by Huppert [J. Fluid Mech. 121, 43--58 (1982)] for modelling viscous dam-break waves, we end up with a nonlinear diffusion equation for the flow depth, which is solved numerically. Theory is compared with experimental results. Excellent agreement is found in the limit of low Reynolds numbers (i.e., for flow Reynolds numbers lower than 20) for the front position over time and flow depth profile. The Newtonian model has sometimes been used to describe the flow behaviour of natural materials such as snow and debris suspensions, but the majority of existing approaches rely on more elaborate constitutive equations. So there is no direct application of the results presented here to real flow conditions. Yet, our study sheds light on the mechanisms involved in basal entrainment. We provide evidence that the whole layer of loose material is entrained quickly once the flow makes contact with the erodible layer. As this process occurs

  4. Scale-up of a fluid-bed process for production of light olefins from methanol

    SciTech Connect

    Gould, R.M.; Avidan, A.A.; Soto, J.L.; Chang, C.D.; Socha, R.F.

    1986-01-01

    Mobil Research and Development Corporation has developed a fluid-bed process for the production of olefins from methanol. The olefins can be converted to gasoline, distillate, and/or aviation fuels by commercially available technologies. The process is based on the ZSM-5 family of shape selective zeolite catalysts. Initial development in fixed and fluid-bed micro-units gave total olefins selectivities exceeding 75 wt% of hydrocarbons with complete methanol conversion. Scale-up to a 4 BPD fluid-bed pilot plant was successful in maintaining high olefin yield. The process has recently been scaled up in a 100 BPD demonstration plant in Germany.

  5. Adsorbent and adsorbent bed for materials capture and separation processes

    SciTech Connect

    Liu, Wei

    2011-01-25

    A method device and material for performing adsorption wherein a fluid mixture is passed through a channel in a structured adsorbent bed having a solid adsorbent comprised of adsorbent particles having a general diameter less than 100 um, loaded in a porous support matrix defining at least one straight flow channel. The adsorbent bed is configured to allow passage of a fluid through said channel and diffusion of a target material into said adsorbent under a pressure gradient driving force. The targeted molecular species in the fluid mixture diffuses across the porous support retaining layer, contacts the adsorbent, and adsorbs on the adsorbent, while the remaining species in the fluid mixture flows out of the channel.

  6. A fluidized bed process for electron sterilization of powders

    NASA Astrophysics Data System (ADS)

    Nablo, Sam V.; Wood, James C.; Desrosiers, Marc F.; Nagy, Vitaly Yu.

    1998-06-01

    A small capacity (100 g.s -1) pilot system is described for presentation of powders and fine aggregates at high velocity, to an electron beam. Electron beam dose rate is continuously monitored in real time, while the thickness of the fluidized bed used to pneumatically transport the product can be monitored and controlled using beta-gauge techniques. Using electron paramagnetic resonance (EPR) techniques, alanine power mixed with the product is used for precise determination of dose delivered to the powder stream. Thin film dosimeters transported in the bed are also used for dose determination. Results with a variety of products are presented using both dose rate and velocity as the independent variables. Lethality data for the bioburdens present in several powdered foodstuffs are discussed.

  7. Fluidized bed gasification ash reduction and removal process

    DOEpatents

    Schenone, Carl E.; Rosinski, Joseph

    1984-12-04

    In a fluidized bed gasification system an ash removal system to reduce the particulate ash to a maximum size or smaller, allow the ash to cool to a temperature lower than the gasifier and remove the ash from the gasifier system. The system consists of a crusher, a container containing level probes and a means for controlling the rotational speed of the crusher based on the level of ash within the container.

  8. Basal entrainment by Newtonian gravity-driven flows

    NASA Astrophysics Data System (ADS)

    Bates, Belinda M.; Andreini, Nicolas; Ancey, Christophe

    2016-05-01

    Gravity-driven flows can erode the bed along which they descend and increase their mass by a factor of 10 or more. This process is called "basal entrainment." Although documented by field observations and laboratory experiments, it remains poorly understood. This paper examines what happens when a viscous gravity-driven flow generated by releasing a fixed volume of incompressible Newtonian fluid encounters a stationary layer (composed of fluid with the same density and viscosity). Models based on depth-averaged mass and momentum balance equations deal with bed-flow interfaces as shock waves. In contrast, we use an approach involving the long-wave approximation of the Navier-Stokes equations (lubrication theory), and in this context, bed-flow interfaces are acceleration waves that move quickly across thin stationary layers. The incoming flow digs down into the bed, pushing up downstream material, thus advancing the flow front. Extending the method used by Huppert ["The propagation of two-dimensional and axisymmetric viscous gravity currents over a rigid horizontal surface," J. Fluid Mech. 121, 43-58 (1982)] for modeling viscous dam-break waves, we end up with a nonlinear diffusion equation for the flow depth, which is solved numerically. Theory is compared with experimental results. Excellent agreement is found in the limit of low Reynolds numbers (i.e., for flow Reynolds numbers lower than 20) for the front position over time and flow depth profile.

  9. Exploring Entrainment Patterns of Human Emotion in Social Media

    PubMed Central

    Luo, Chuan; Zhang, Zhu

    2016-01-01

    Emotion entrainment, which is generally defined as the synchronous convergence of human emotions, performs many important social functions. However, what the specific mechanisms of emotion entrainment are beyond in-person interactions, and how human emotions evolve under different entrainment patterns in large-scale social communities, are still unknown. In this paper, we aim to examine the massive emotion entrainment patterns and understand the underlying mechanisms in the context of social media. As modeling emotion dynamics on a large scale is often challenging, we elaborate a pragmatic framework to characterize and quantify the entrainment phenomenon. By applying this framework on the datasets from two large-scale social media platforms, we find that the emotions of online users entrain through social networks. We further uncover that online users often form their relations via dual entrainment, while maintain it through single entrainment. Remarkably, the emotions of online users are more convergent in nonreciprocal entrainment. Building on these findings, we develop an entrainment augmented model for emotion prediction. Experimental results suggest that entrainment patterns inform emotion proximity in dyads, and encoding their associations promotes emotion prediction. This work can further help us to understand the underlying dynamic process of large-scale online interactions and make more reasonable decisions regarding emergency situations, epidemic diseases, and political campaigns in cyberspace. PMID:26953692

  10. Exploring Entrainment Patterns of Human Emotion in Social Media.

    PubMed

    He, Saike; Zheng, Xiaolong; Zeng, Daniel; Luo, Chuan; Zhang, Zhu

    2016-01-01

    Emotion entrainment, which is generally defined as the synchronous convergence of human emotions, performs many important social functions. However, what the specific mechanisms of emotion entrainment are beyond in-person interactions, and how human emotions evolve under different entrainment patterns in large-scale social communities, are still unknown. In this paper, we aim to examine the massive emotion entrainment patterns and understand the underlying mechanisms in the context of social media. As modeling emotion dynamics on a large scale is often challenging, we elaborate a pragmatic framework to characterize and quantify the entrainment phenomenon. By applying this framework on the datasets from two large-scale social media platforms, we find that the emotions of online users entrain through social networks. We further uncover that online users often form their relations via dual entrainment, while maintain it through single entrainment. Remarkably, the emotions of online users are more convergent in nonreciprocal entrainment. Building on these findings, we develop an entrainment augmented model for emotion prediction. Experimental results suggest that entrainment patterns inform emotion proximity in dyads, and encoding their associations promotes emotion prediction. This work can further help us to understand the underlying dynamic process of large-scale online interactions and make more reasonable decisions regarding emergency situations, epidemic diseases, and political campaigns in cyberspace.

  11. Exploring Entrainment Patterns of Human Emotion in Social Media.

    PubMed

    He, Saike; Zheng, Xiaolong; Zeng, Daniel; Luo, Chuan; Zhang, Zhu

    2016-01-01

    Emotion entrainment, which is generally defined as the synchronous convergence of human emotions, performs many important social functions. However, what the specific mechanisms of emotion entrainment are beyond in-person interactions, and how human emotions evolve under different entrainment patterns in large-scale social communities, are still unknown. In this paper, we aim to examine the massive emotion entrainment patterns and understand the underlying mechanisms in the context of social media. As modeling emotion dynamics on a large scale is often challenging, we elaborate a pragmatic framework to characterize and quantify the entrainment phenomenon. By applying this framework on the datasets from two large-scale social media platforms, we find that the emotions of online users entrain through social networks. We further uncover that online users often form their relations via dual entrainment, while maintain it through single entrainment. Remarkably, the emotions of online users are more convergent in nonreciprocal entrainment. Building on these findings, we develop an entrainment augmented model for emotion prediction. Experimental results suggest that entrainment patterns inform emotion proximity in dyads, and encoding their associations promotes emotion prediction. This work can further help us to understand the underlying dynamic process of large-scale online interactions and make more reasonable decisions regarding emergency situations, epidemic diseases, and political campaigns in cyberspace. PMID:26953692

  12. Effect of ash content on the combustion process of simulated MSW in the fixed bed.

    PubMed

    Sun, Rui; Ismail, Tamer M; Ren, Xiaohan; Abd El-Salam, M

    2016-02-01

    This paper experimentally and numerically investigates the effects of ash content on the combustion process of simulated Municipal Solid Waste (MSW). A fixed-bed experimental reactor was utilized to reveal the combustion characteristics. Temperature distributions, ignition front velocity, and the characteristics of gas species' release were measured and simulated during the combustion process. In the present work, the two-dimensional unsteady mathematical heterogeneous model was developed to simulate the combustion process in the bed, including the process rate model as well as NOx production model. The simulation results in the bed are accordant with the experimental results. The results show that as ash content increases, the lower burning rate of fuel results in char particles leaving the grate without being fully burned, causing a loss of combustible material in the MSW in a fixed bed and therefore reducing the combustion efficiency and increasing the burning time of the MSW.

  13. Modeling electrowinning process in an expanded bed electrode.

    PubMed

    Thilakavathi, R; Balasubramanian, N; Ahmed Basha, C

    2009-02-15

    A theoretical model has been developed to describe the flow behavior of conducting particles in a fluidized bed electrode for electro winning of metal ions present in the dilute solution. Model equations have been developed for potential and current distributions and mass transfer rates. The influence of operating parameters on particle growth has been critically examined. It has been observed from the present investigation that the particle size increased with electrolysis time. The present model simulations have been compared with the experimental data reported in the literature and observed that the model predictions satisfactorily match with the reported experimental findings. PMID:18562092

  14. Physiology of circadian entrainment.

    PubMed

    Golombek, Diego A; Rosenstein, Ruth E

    2010-07-01

    Mammalian circadian rhythms are controlled by endogenous biological oscillators, including a master clock located in the hypothalamic suprachiasmatic nuclei (SCN). Since the period of this oscillation is of approximately 24 h, to keep synchrony with the environment, circadian rhythms need to be entrained daily by means of Zeitgeber ("time giver") signals, such as the light-dark cycle. Recent advances in the neurophysiology and molecular biology of circadian rhythmicity allow a better understanding of synchronization. In this review we cover several aspects of the mechanisms for photic entrainment of mammalian circadian rhythms, including retinal sensitivity to light by means of novel photopigments as well as circadian variations in the retina that contribute to the regulation of retinal physiology. Downstream from the retina, we examine retinohypothalamic communication through neurotransmitter (glutamate, aspartate, pituitary adenylate cyclase-activating polypeptide) interaction with SCN receptors and the resulting signal transduction pathways in suprachiasmatic neurons, as well as putative neuron-glia interactions. Finally, we describe and analyze clock gene expression and its importance in entrainment mechanisms, as well as circadian disorders or retinal diseases related to entrainment deficits, including experimental and clinical treatments. PMID:20664079

  15. Fast fluidized bed steam generator

    DOEpatents

    Bryers, Richard W.; Taylor, Thomas E.

    1980-01-01

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

  16. Development of second-generation pressurized fluidized bed combustion process

    SciTech Connect

    Wolowodiuk, W.; Robertson, A.; Bonk, D.

    1995-12-01

    Under the sponsorship of the United States Department of Energy, Foster Wheeler Development Corporation, and its team members, Westinghouse, Gilbert/Commonwealth, and the Institute of Gas Technology are developing second-generation pressurized fluidized bed combustion technology capable of achieving net plant efficiency in excess of 45 percent based on the higher heating value of the coal. A three-phase program entails design and costing of a 500 MWe power plant and identification of developments needed to commercialize this technology (Phase 1), testing of individual components (Phase 2), and finally testing these components in an integrated mode (Phase 3). This paper briefly describes the results of the first two phases as well as the progress on the third phase. Since other projects which use the same technology are in construction or in negotiation stages-namely, the Power System Development Facility and the Four Rivers Energy Modernization Projects-brief descriptions of these are also included.

  17. Mesler entrainment in alcohols

    NASA Astrophysics Data System (ADS)

    Saylor, J. R.; Sundberg, R. K.

    2012-11-01

    When a drop impacts a flat surface of the same liquid at an intermediate velocity, the impact can result in the formation of a very large number of very small bubbles. At lower velocities, drops bounce or float, and at larger velocities a single bubble forms, or there is a splash. The formation of large numbers of small bubbles during intermediate velocity impacts is termed Mesler entrainment and its controlling mechanism is poorly understood. Existing research has shown that Mesler entrainment is highly irreproducible when water is the working fluid, and very reproducible when silicone oil is the working fluid. Whether this is because water is problematic, or silicone oil is uniquely well-suited, is unclear. To answer this question, experiments were conducted using three different alcohols. The results of these experiments were very reproducible for all alcohols tested, suggesting that there is something unique about water which accounts for its lack of reproducibility. The data from these experiments were also used to develop a dimensionless group that quantifies the conditions under which Mesler entrainment occurs. This dimensionless group is used to provide insight into the mechanism of this unique method of bubble formation.

  18. Estimating rates of debris flow entrainment from ground vibrations

    NASA Astrophysics Data System (ADS)

    Kean, J. W.; Coe, J. A.; Coviello, V.; Smith, J. B.; McCoy, S. W.; Arattano, M.

    2015-08-01

    Debris flows generate seismic waves as they travel downslope and can become more dangerous as they entrain sediment along their path. We present field observations that show a systematic relation between the magnitude of seismic waves and the amount of erodible sediment beneath the flow. Specifically, we observe that a debris flow traveling along a channel filled initially with sediment 0.34 m thick generates about 2 orders of magnitude less spectral power than a similar-sized flow over the same channel without sediment fill. We adapt a model from fluvial seismology to explain this observation and then invert it to estimate the level of bed sediment (and rate of entrainment) beneath a passing series of surges. Our estimates compare favorably with previous direct measurements of entrainment rates at the site, suggesting the approach may be a new indirect way to obtain rare field constraints needed to test models of debris flow entrainment.

  19. MEASUREMENT OF ENTRAINED ORGANIC DROPLET SIZES AND TOTAL CONCENTRATION FOR AQUEOUS STREAMS FROM THE CAUSTIC-SIDE SOLVENT EXTRACTION PROCESS

    SciTech Connect

    Nash, C; Samuel Fink, S; Michael Restivo, M; Dan Burns, D; Wallace Smith, W; S Crump, S; Zane Nelson, Z; Thomas Peters, T; Fernando Fondeur, F; Michael Norato, M

    2007-02-01

    The Modular Caustic-Side Solvent Extraction Unit (MCU) and the Salt Waste Processing Facility will remove radioactive cesium from Savannah River Site supernate wastes using an organic solvent system. Both designs include decanters and coalescers to reduce carryover of organic solvent droplets. Savannah River National Laboratory personnel conducted experimental demonstrations using a series of four 2-cm centrifugal contactors. They also examined organic carryover during operation of a CINC (Costner Industries Nevada Corporation) V-5 contactor under prototypical conditions covering the range of expected MCU operation. This report details the findings from those studies and the implications on design for the MCU.

  20. Infrared thermography for laser-based powder bed fusion additive manufacturing processes

    NASA Astrophysics Data System (ADS)

    Moylan, Shawn; Whitenton, Eric; Lane, Brandon; Slotwinski, John

    2014-02-01

    Additive manufacturing (AM) has the potential to revolutionize discrete part manufacturing, but improvements in processing of metallic materials are necessary before AM will see widespread adoption. A better understanding of AM processes, resulting from physics-based modeling as well as direct process metrology, will form the basis for these improvements. Infrared (IR) thermography of AM processes can provide direct process metrology, as well as data necessary for the verification of physics-based models. We review selected works examining how IR thermography was implemented and used in various powder-bed AM processes. This previous work, as well as significant experience at the National Institute of Standards and Technology in temperature measurement and IR thermography for machining processes, shapes our own research in AM process metrology with IR thermography. We discuss our experimental design, as well as plans for future IR measurements of a laser-based powder bed fusion AM process.

  1. Infrared thermography for laser-based powder bed fusion additive manufacturing processes

    SciTech Connect

    Moylan, Shawn; Whitenton, Eric; Lane, Brandon; Slotwinski, John

    2014-02-18

    Additive manufacturing (AM) has the potential to revolutionize discrete part manufacturing, but improvements in processing of metallic materials are necessary before AM will see widespread adoption. A better understanding of AM processes, resulting from physics-based modeling as well as direct process metrology, will form the basis for these improvements. Infrared (IR) thermography of AM processes can provide direct process metrology, as well as data necessary for the verification of physics-based models. We review selected works examining how IR thermography was implemented and used in various powder-bed AM processes. This previous work, as well as significant experience at the National Institute of Standards and Technology in temperature measurement and IR thermography for machining processes, shapes our own research in AM process metrology with IR thermography. We discuss our experimental design, as well as plans for future IR measurements of a laser-based powder bed fusion AM process.

  2. Observational constraints on entrainment and the entrainment interface layer in stratocumulus

    NASA Astrophysics Data System (ADS)

    Carman, J. K.; Rossiter, D. L.; Khelif, D.; Jonsson, H. H.; Faloona, I. C.; Chuang, P. Y.

    2012-01-01

    Aircraft sampling of the stratocumulus-topped boundary layer (STBL) during the Physics of Stratocumulus Top (POST) experiment was primarily achieved using sawtooth flight patterns, during which the atmospheric layer 100 m above and below cloud top was sampled at a frequency of once every 2 min. The large data set that resulted from each of the 16 flights document the complex structure and variability of this interfacial region in a variety of conditions. In this study, we first describe some properties of the entrainment interface layer (EIL), where strong gradients in turbulent kinetic energy (TKE), potential temperature and moisture can be found. We find that defining the EIL by the first two properties tend to yield similar results, but that moisture can be a misleading tracer of the EIL. These results are consistent with studies using large-eddy simulations. We next utilize the POST data to shed light on and constrain processes relevant to entrainment, a key process in the evolution of the STBL that to-date is not well-represented even by high resolution models. We define "entrainment efficiency" as the ratio of the TKE consumed by entrainment to that generated within the STBL (primarily by cloud-top cooling). We find values for the entrainment efficiency that vary by 1.5 orders of magnitude, which is even greater than the one order magnitude that previous modeling results have suggested. Our analysis also demonstrate that the entrainment efficiency depends on the strength of the stratification of the EIL, but not on the TKE in the cloud top region. The relationships between entrainment efficiency and other STBL parameters serve as novel observational contraints for simulations of entrainment in such systems.

  3. Observational constraints on entrainment and the entrainment interface layer in stratocumulus

    NASA Astrophysics Data System (ADS)

    Carman, J. K.; Rossiter, D. L.; Khelif, D.; Jonsson, H. H.; Faloona, I. C.; Chuang, P. Y.

    2012-11-01

    Aircraft sampling of the stratocumulus-topped boundary layer (STBL) during the Physics of Stratocumulus Top (POST) experiment was primarily achieved using sawtooth flight patterns, during which the atmospheric layer 100 m above and below cloud top was sampled at a frequency of once every 2 min. The large data set that resulted from each of the 16 flights document the complex structure and variability of this interfacial region in a variety of conditions. In this study, we first describe some properties of the entrainment interface layer (EIL), where strong gradients in turbulent kinetic energy (TKE), potential temperature and moisture can be found. We find that defining the EIL by the first two properties tends to yield similar results, but that moisture can be a misleading tracer of the EIL. These results are consistent with studies using large-eddy simulations. We next utilize the POST data to shed light on and constrain processes relevant to entrainment, a key process in the evolution of the STBL that to-date is not well-represented even by high resolution models. We define "entrainment efficiency" as the ratio of the TKE consumed by entrainment to that generated within the STBL (primarily by cloud-top cooling). We find values for the entrainment efficiency that vary by 1.5 orders of magnitude, which is even greater than the one order magnitude that previous modeling results have suggested. Our analysis also demonstrates that the entrainment efficiency depends on the strength of the stratification of the EIL, but not on the TKE in the cloud top region. The relationships between entrainment efficiency and other STBL parameters serve as novel observational contraints for simulations of entrainment in such systems.

  4. Development of the fluidized bed thermal treatment process for treating mixed waste

    SciTech Connect

    Semones, G.B.; Williams, P.M.; Stiefvater, S.P.; Mitchell, D.L.; Roecker, B.D.

    1993-05-01

    A fluidized bed system is being developed at Rocky Flats for the treatment of mixed waste (a mixture of radioactive and chemically hazardous waste). The current program builds on experience gained in the 1970`s and 1980`s in tests with bench-scale, pilot-scale, and demonstration-scale fluidized bed systems. The system operates at low temperatures ({approx} 525--600{degree}C) which eliminates many of the disadvantages associated with high temperature thermal treatment processes. The process has shown the ability to destroy polychlorinated biphenyls (PCB`s) with 99.9999% (``six-nines``) destruction efficiency in tests monitored by the Environmental Protection Agency (EPA). The bed makes use of in situ neutralization of acidic off-gases by incorporating sodium carbonate (Na{sub 2}CO{sub 3}) in the bed media. This eliminates using wet scrubbers to treat the off-gas; these produce a high volume of secondary waste. Once in operation, it is expected that the fluidized bed process will yield up to a 40:1 reduction in the volume of the waste.

  5. Entrainment and mixing mechanism in monsoon clouds

    NASA Astrophysics Data System (ADS)

    Bera, Sudarsan; Prabhakaran, Thara; Pandithurai, Govindan; Brenguier, Jean-Louis

    2015-04-01

    Entrainment and consequent mixing impacts the cloud microphysical parameters and droplet size distribution (DSD) significantly which are very important for cloud radiative properties and the mechanism for first rain drop formation. The entrainment and mixing mechanisms are investigated in this study using in situ observations in warm cumulus clouds over monsoon region. Entrainment is discussed in the framework of the homogeneous and inhomogeneous mixing concepts and their effects on cloud droplet size distribution, number concentration, liquid water content and mean radius are described. The degree of homogeneity increases with droplet number concentration and adiabatic fraction, indicating homogeneous type mixing in the cloud core where dilution is less. Inhomogeneous mixing is found to be a dominating process at cloud edges where dilution is significant. Cloud droplet size distribution (DSD) is found to shift towards lower sizes during a homogeneous mixing event in the cloud core whereas spectral width of DSD decreases due to inhomogeneous mixing at cloud edges. Droplet size spectra suggests that largest droplets are mainly formed in the less diluted cloud core while diluted cloud edges have relatively smaller droplets, so that raindrop formation occurs mainly in the core of the cloud. The origin of the entrained parcels in deep cumulus clouds is investigated using conservative thermodynamical parameters. The entrained parcels originate from a level close to the observation level or slightly below through lateral edges. Cloud edges are significantly diluted due to entrainment of sub-saturated environmental air which can penetrate several hundred meters inside the cloud before it gets mixed completely with the cloud mass. Less diluted parcels inside the cloud core originates from a level much below the cloud base height. Penetrating downdraft from cloud top is seldom observed at the observation level and strong downdrafts may be attributed to in-cloud oscillation

  6. Entrainment of neural oscillations as a modifiable substrate of attention.

    PubMed

    Calderone, Daniel J; Lakatos, Peter; Butler, Pamela D; Castellanos, F Xavier

    2014-06-01

    Brain operation is profoundly rhythmic. Oscillations of neural excitability shape sensory, motor, and cognitive processes. Intrinsic oscillations also entrain to external rhythms, allowing the brain to optimize the processing of predictable events such as speech. Moreover, selective attention to a particular rhythm in a complex environment entails entrainment of neural oscillations to its temporal structure. Entrainment appears to form one of the core mechanisms of selective attention, which is likely to be relevant to certain psychiatric disorders. Deficient entrainment has been found in schizophrenia and dyslexia and mounting evidence also suggests that it may be abnormal in attention-deficit/hyperactivity disorder (ADHD). Accordingly, we suggest that studying entrainment in selective-attention paradigms is likely to reveal mechanisms underlying deficits across multiple disorders.

  7. Automatic River Bed Grain Size Measurement Using Image Processing and Support Vector Machines

    NASA Astrophysics Data System (ADS)

    Bellugi, D.; Nelson, P. A.; Dietrich, W. E.

    2010-12-01

    Gravel-bedded rivers cut through hilly and mountainous areas, driving landscape evolution and creating a diverse habitat upon which river food web ecosystems develop. Our understanding of the mechanics underlying important processes in fluvial geomorphology, hydrodynamics, and aquatic ecology inevitably requires knowledge about the grain size distribution of river bed material. Standard methods of sampling bed surface material may introduce errors due to biases and inadequate sample size. Alternative areal or volumetric sampling procedures are often impractical, particularly in coarse channel beds. Furthermore, all invasive sampling techniques can compromise laboratory flume experiments. These concerns suggest that there is a practical need for a reliable, automated, non-invasive procedure for obtaining the grain size distribution of bed surface material. Although considerable effort has been made to automatically generate grain size distributions using image processing and analysis techniques, the problem remains quite challenging: issues such as varying lighting conditions, partial immersion of particles in water, and heterogeneous mineralogy result in ambiguities that cannot be easily resolved. Feature extraction introduces further biases due to over- or under-segmentation of the image. Moreover, unless the grain distributions are fairly homogeneous between different locations, and images are collected in similar fashion, it is difficult to parametrize any such method in a transferable manner. In this study we present an image processing and machine learning procedure to automatically identify and measure grains from photographic images of gravel-bedded rivers. We apply the state-of-the-art of image segmentation techniques, making use of local cues such as brightness, color, and texture in a multi-scale approach. These cues are globalized using a graph partitioning method on the oriented contour signal. The resulting boundary probability signal is treated by a

  8. Powder Bed Layer Characteristics: The Overseen First-Order Process Input

    NASA Astrophysics Data System (ADS)

    Mindt, H. W.; Megahed, M.; Lavery, N. P.; Holmes, M. A.; Brown, S. G. R.

    2016-08-01

    Powder Bed Additive Manufacturing offers unique advantages in terms of manufacturing cost, lot size, and product complexity compared to traditional processes such as casting, where a minimum lot size is mandatory to achieve economic competitiveness. Many studies—both experimental and numerical—are dedicated to the analysis of how process parameters such as heat source power, scan speed, and scan strategy affect the final material properties. Apart from the general urge to increase the build rate using thicker powder layers, the coating process and how the powder is distributed on the processing table has received very little attention to date. This paper focuses on the first step of every powder bed build process: Coating the process table. A numerical study is performed to investigate how powder is transferred from the source to the processing table. A solid coating blade is modeled to spread commercial Ti-6Al-4V powder. The resulting powder layer is analyzed statistically to determine the packing density and its variation across the processing table. The results are compared with literature reports using the so-called "rain" models. A parameter study is performed to identify the influence of process table displacement and wiper velocity on the powder distribution. The achieved packing density and how that affects subsequent heat source interaction with the powder bed is also investigated numerically.

  9. Study of instrumentation needs for process control and safety in coal fluidized-bed combustion systems

    SciTech Connect

    Herzenberg, C.L.; Griggs, K.E.; Henry, R.F.; Podolski, W.F.

    1981-02-01

    A study was conducted to evaluate the current state of the art of instrumentation for planned and operating fluidized-bed combustion systems. This study is intended to identify instrumentation needs and serve as a data base for projects to develop this instrumentation. A considerable number of needs for measurements for which presently available instrumentation is not suitable were reported by respondents. The identified deficiencies are presented with the associated physical parameter ranges for FBC processes. New techniques and instrumentation under development, as well as some available alternative instruments, are discussed briefly. Also, newly instituted mechanisms for technical information exchange on instrumentation for fossil energy applications are identified. Development of instruments to meet the identified measurement deficiencies is recommended in order to ensure the feasibility of automatic control of large-scale fluidized-bed combustion systems, and to advance the state of the art of fluidized-bed combustion technology.

  10. Linking River Management-Induced Perturbations of Hydrologic and Sediment Regimes to Geomorphic Processes Along a Highly-Dynamic Gravel-Bed River: Snake River, WY.

    NASA Astrophysics Data System (ADS)

    Leonard, C.; Legleiter, C. J.

    2015-12-01

    Encroachment of human development onto river floodplains creates a need to stabilize rivers and provide flood protection. Structural interventions, such as levees, often perturb hydrologic and sediment regimes and thus can initiate morphological responses. An understanding of how human activities affect river morphodynamics and trigger channel change is needed to anticipate future river responses and facilitate effective restoration. This study examines approximately 66 km of the Snake River, WY, USA, and links sediment transport processes to channel form and behavior by developing a morphological sediment budget that spans both a natural, unconfined reach and a reach confined by artificial levees. Sediment transport rates are inferred from the morphological sediment budget and a bed mobility study is used to estimate entrainment thresholds that allow us to link the hydrological regime during the sediment budget period to the observed channel changes. Results indicate that lateral constriction by levees triggers a positive feedback mechanism by incising the bed, focusing flow energy, thus increasing transport capacity, and leading to armoring of the bed. In other systems, armoring promotes widening of the channel but in this case levees prevent widening and the channel instead migrates across the braidplain rapidly, producing further erosion of bars and vegetated islands that is expressed as negative net volumetric changes and increased sediment transport rates. Furthermore, decreased slopes and reduced discharges due to dam regulation in the upstream unconfined reach cause gravel sheets to stall on bars and in other areas of storage, creating a spatial discontinuity in sediment conveyance downstream, and thus contributing to the sediment deficit within the leveed reach.

  11. Entrainment and mixing in stratified shear flows

    NASA Astrophysics Data System (ADS)

    Strang, Eric James

    1997-12-01

    The results of a laboratory experiment designed to study turbulent entrainment at sheared density interfaces are described. In the parameter ranges investigated the entrainment problem is mainly determined by two parameters, the bulk Richardson number RiB = /Delta bD//Delta U2 and the frequency ratio fN = ND//Delta U. When RiB > 1.5, the buoyancy effects play a governing role, whence interfacial instabilities locally mix heavy and light fluids. The nature of interfacial instabilities is governed by RiB or a related quantity, the mean local gradient Richardson number /overline [Ri]g=/overline [N(z)]2/(/overline[/partial u//partial z)]2, where N(z) is the Brunt-Vaisala frequency local to the interface. When RiB < 5 (or /overline [Rig] < 1), the interfacial mixing is dominated by Kelvin- Helmholtz (K-H) instabilities. Interfacial swelling as a result of the collective breakdown of K-H billows into turbulence persists for a time dictated by the rates of local generation and removal of mixed fluid, and the two processes appear to be coadjutant (with a maximum flux Richardson number or mixing efficiency of Rif ~ 0.15-0.4) when RiB≃ 3-5. At RiB~ 5, the K-H regime transitions to a new regime wherein the interface is dominated by interfacial/Holmboe wave instabilities. Here, the entrainment rates are much smaller and there is no evidence of interfacial swelling. In the K-H regime, the swelling of the interface introduces its own forcing time scale, which excites and radiates internal waves in the lower layer if it is continuously stratified. Consequently, the amount of energy available for entrainment decreases and, depending on fN, the entrainment velocities in the linearly stratified case can be substantially smaller than the two-layer case (up to 50%). In the interfacial/Holmboe wave breaking regime, internal wave radiation to the bottom layer is much smaller, so as the difference in entrainment rates of the two-layer and linearly stratified cases. Furthermore, when Ri

  12. Evaluation of process errors in bed load sampling using a dune model

    USGS Publications Warehouse

    Gomez, B.; Troutman, B.M.

    1997-01-01

    Reliable estimates of the streamwide bed load discharge obtained using sampling devices are dependent upon good at-a-point knowledge across the full width of the channel. Using field data and information derived from a model that describes the geometric features of a dune train in terms of a spatial process observed at a fixed point in time, we show that sampling errors decrease as the number of samples collected increases, and the number of traverses of the channel over which the samples are collected increases. It also is preferable that bed load sampling be conducted at a pace which allows a number of bed forms to pass through the sampling cross section. The situations we analyze and simulate pertain to moderate transport conditions in small rivers. In such circumstances, bed load sampling schemes typically should involve four or five traverses of a river, and the collection of 20-40 samples at a rate of five or six samples per hour. By ensuring that spatial and temporal variability in the transport process is accounted for, such a sampling design reduces both random and systematic errors and hence minimizes the total error involved in the sampling process.

  13. Development of an inclined liquid fluidized bed for tar sand processing

    SciTech Connect

    Johnson, L.A. Jr.

    1989-12-01

    An inclined liquid fluidized-bed reactor (ILFBR) system has been developed and successfully operated for 24 hours. Modifications to the previously tested ILFBR systems include incorporation of a oil fluidizing zone in the front of the fluid bed, an increase in the angle of the fluid bed to {minus}12{degree} (the minus sign shows that the discharges is below the horizontal level of the inlet), and reduction of the fluidizing gas velocities equal to or below the minimum fluidization velocity. These changes produced a functional bubbling slurry bed for the processing of tar sand. The produced oils and spent sand resemble the products from screw pyrolysis reactor (SPR) tests suggesting that the ILFBR system functioned similar to the SPR systems with the recycle oil pyrolysis and extraction (ROPE{copyright}) process. With slight modifications in the heater control and placement, the system will be ready for development of operational parameters for the surface processing of tar sand. 10 refs., 2 figs., 1 tab.

  14. Entraining synthetic genetic oscillators

    NASA Astrophysics Data System (ADS)

    Wagemakers, Alexandre; Buldú, Javier M.; Sanjuán, Miguel A. F.; de Luis, Oscar; Izquierdo, Adriana; Coloma, Antonio

    2009-09-01

    We propose a new approach for synchronizing a population of synthetic genetic oscillators, which consists in the entrainment of a colony of repressilators by external modulation. We present a model where the repressilator dynamics is affected by periodic changes in temperature. We introduce an additional plasmid in the bacteria in order to correlate the temperature variations with the enhancement of the transcription rate of a certain gene. This can be done by introducing a promoter that is related to the heat shock response. This way, the expression of that gene results in a protein that enhances the overall oscillations. Numerical results show coherent oscillations of the population for a certain range of the external frequency, which is in turn related to the natural oscillation frequency of the modified repressilator. Finally we study the transient times related with the loss of synchronization and we discuss possible applications in biotechnology of large-scale production coupled to synchronization events induced by heat shock.

  15. Power plant intake entrainment analysis

    SciTech Connect

    Edinger, J.E.; Kolluru, V.S.

    2000-04-01

    Power plant condenser cooling water intake entrainment of fish eggs and larvae is becoming an issue in evaluating environmental impacts around the plants. Methods are required to evaluate intake entrainment on different types of water bodies. Presented in this paper is a derivation of the basic relationships for evaluating entrainment from the standing crop of fish eggs and larvae for different regions of a water body, and evaluating the rate of entrainment from the standing crop. These relationships are coupled with a 3D hydrodynamic and transport model that provides the currents and flows required to complete the entrainment evaluation. Case examples are presented for a simple river system, and for the more complex Delaware River Estuary with multiple intakes. Example evaluations are made for individual intakes, and for the cumulative impacts of multiple intakes.

  16. Mechanistic modelling of fluidized bed drying processes of wet porous granules: a review.

    PubMed

    Mortier, Séverine Thérèse F C; De Beer, Thomas; Gernaey, Krist V; Remon, Jean Paul; Vervaet, Chris; Nopens, Ingmar

    2011-10-01

    Fluidized bed dryers are frequently used in industrial applications and also in the pharmaceutical industry. The general incentives to develop mechanistic models for pharmaceutical processes are listed, and our vision on how this can particularly be done for fluidized bed drying processes of wet granules is given. This review provides a basis for future mechanistic model development for the drying process of wet granules in pharmaceutical processes. It is intended for a broad audience with a varying level of knowledge on pharmaceutical processes and mathematical modelling. Mathematical models are powerful tools to gain process insight and eventually develop well-controlled processes. The level of detail embedded in such a model depends on the goal of the model. Several models have therefore been proposed in the literature and are reviewed here. The drying behaviour of one single granule, a porous particle, can be described using the continuum approach, the pore network modelling method and the shrinkage of the diameter of the wet core approach. As several granules dry at a drying rate dependent on the gas temperature, gas velocity, porosity, etc., the moisture content of a batch of granules will reside in a certain interval. Population Balance Model (ling) (PBM) offers a tool to describe the distribution of particle properties which can be of interest for the application. PBM formulation and solution methods are therefore reviewed. In a fluidized bed, the granules show a fluidization pattern depending on the geometry of the gas inlet, the gas velocity, characteristics of the particles, the dryer design, etc. Computational Fluid Dynamics (CFD) allows to model this behaviour. Moreover, turbulence can be modelled using several approaches: Reynolds-averaged Navier-Stokes Equations (RANS) or Large Eddy Simulation (LES). Another important aspect of CFD is the choice between the Eulerian-Lagrangian and the Eulerian-Eulerian approach. Finally, the PBM and CFD frameworks

  17. Monitoring granulation rate processes using three PAT tools in a pilot-scale fluidized bed.

    PubMed

    Tok, Ai Tee; Goh, Xueping; Ng, Wai Kiong; Tan, Reginald B H

    2008-01-01

    The purpose of this research was to analyze and compare the responses of three Process Analytical Technology (PAT) techniques applied simultaneously to monitor a pilot-scale fluidized bed granulation process. Real-time measurements using focused beam reflectance measurement (Lasentec FBRM) and near-infra red spectroscopy (Bruker NIR) were taken by inserting in-line probes into the fluidized bed. Non-intrusive acoustic emission measurements (Physical Acoustic AE) were performed by attaching piezoelectric sensors on the external wall of the fluidized bed. Powder samples were collected at regular intervals during the granulation process and characterized offline using laser diffraction, scanning electron microscopy, stereo-optical microscopy and loss on drying method. PAT data comprising chord length distribution and chord count (from FBRM), absorption spectra (from NIR) and average signal levels and counts (from AE) were compared with the particle properties measured using offline samples. All three PAT techniques were able to detect the three granulation regimes or rate processes (wetting and nucleation, consolidation and growth, breakage) to varying degrees of sensitivity. Being dependent on optical signals, the sensitivities of the FBRM and NIR techniques were susceptible to fouling on probe windows. The AE technique was sensitive to background fluidizing air flows and external interferences. The sensitivity, strengths and weaknesses of the PAT techniques examined may facilitate the selection of suitable PAT tools for process development and scale-up studies.

  18. The development of an integrated multistaged fluid bed retorting process. Annual report, October 1991--September 1992

    SciTech Connect

    Carter, S.; Vego, A.; Stehn, J.; Taulbee, D.; Robl, T.; Hower, J.; Mahboub, K.; Robertson, R.; Hornsberger, P.; Oduroh, P.; Simpson, A.

    1992-12-01

    This report summarizes the progress made on the development of an integrated multistage fluidized bed retorting process (KENTORT II) during the period of October 1, 1991 through September 30, 1992. The KENTORT II process includes integral fluidized bed zones for pyrolysis (shale oil production), gasification (synthesis gas production), and combustion of the spent oil shale for process heat. The purpose of this program is to design and test the KENTORT II process at the 50-lb/hr scale. The work completed this year involved several different areas. Basic studies of the cracking and coking kinetics of shale oil vapors were carried out in fluidized and fixed bed reactors using both freshly generated shale oil vapors and model compounds. The design and fabrication of the 50-lb/hr KENTORT II reactor was completed and installation of the process components was initiated. The raw oil shale sample (Cleveland Member from Montgomery County, Kentucky) for the program was mined, prepared, characterized and stored. A preliminary study of KENTORT II-derived oil for possible paving applications was completed, and it was concluded that the shale exhibits acceptable properties as an asphalt recycling agent.

  19. The development of an integrated multistage fluid bed retorting process. Annual report, September 1990--September 1991

    SciTech Connect

    Carter, S.; Vego, A.; Taulbee, D.; Stehn, J.

    1992-01-01

    This report summarizes the progress made on the development of an integrated multistage fluidized bed retorting process (KENTORT II). The KENTORT II process includes integral fluidized bed zone for pyrolysis, gasification, and combustion of the oil shale. The purpose of this program is to design and test the KENTORT II process at the 50-lb/hr scale. The work performed during this year involved projects that will contribute physical and chemical data for the final design of the 50-lb/hr retort. A cold-flow model of the 50-lb/hr retort was built and tested. The unit demonstrated stable operation and proper fluidization of all beds. Good control of solid recirculation up to the maximum design rate for each loop (200 and 500 lb/hr, respectively) was achieved simultaneously. Basically, the cold-flow model is completely operational and translation of the cold-flow design parameters to the design of the retort is ready to begin. In another aspect of the program, a study of the cracking and coking kinetics of shale oil vapors passed over processed shales was initiated. The addition of a mass spectrometer to the system to monitor total carbon, nitrogen and sulfur evolution in real-time was successful. Coking activities of processed shales were ranked as follows: combusted shale > gasified shale > pyrolyzed shale. Arrangements for conducting an evaluation of KENTORT-derived oil for asphalt applications were finalized and testing was initiated.

  20. Process intensification by direct product sequestration from batch fermentations: application of a fluidised bed, multi-bed external loop contactor

    PubMed

    Hamilton; Morton; Young; Lyddiatt

    1999-08-01

    A critical comparison has been made of the relative efficacy of the primary purification of an extracellular acid protease produced by the yeast Yarrowia lipolytica. The performance of conventional, discrete sequences of fermentation, broth clarification and fixed bed, anion exchange chromatography has been compared with fluidised bed adsorption directly interfaced with post-term fermentation broth and fluidised bed adsorption directly integrated with productive fermentations (so-called direct product sequestration; DPS). Advantages of the latter, in terms of the improved yield and molecular quality of the protease end product are discussed in terms of the design, assembly and operation of component parts of DPS devices and their generic application to other extracellular bioproducts of microbial fermentations. Copyright 1999 John Wiley & Sons, Inc.

  1. Bedload Transport Processes in Armored, Gravel-bed Channels: Impacts of Hydrograph Form

    NASA Astrophysics Data System (ADS)

    Kenworthy, M.; Yager, E.; Yarnell, S. M.

    2014-12-01

    Accurately predicting bed load transport rates remains challenging, with many influential factors still poorly understood, including unsteady flows and stream bed armoring. Nearly all natural channels experience unsteady flows, and hydrograph form varies significantly from gradually (i.e. snowmelt) to rapidly changing flows (i.e. rain driven or many regulated flows). However, most predictive methods neglect hydrograph impacts, and nearly all bedload transport experiments use steady flows. Stream bed armoring likely influences bedload transport rates as well, with the coarser surface limiting the availability of the finer, more mobile grain sizes in the subsurface. It remains uncertain whether armor persists, breaks up, or exchanges particles with bedload during high flow events. Coupled effects of hydrograph form and armor may also be significant, and previous work indicates that more gradual changes in flow promote more significant armoring compared to rapid changes in flow. To better understand the impacts of hydrograph form and armoring on bedload transport processes in gravel-bed rivers, flume experiments were conducted at the University of Idaho's Stream Lab. An armored, equilibrium bed was established as the initial condition for all experiments, which included steady-state discharges and a variety of hydrograph forms from gradually to rapidly changing. Steady-state runs allowed for comparison of bedload transport for a given discharge run singularly and in the context of various hydrographs. Though hydrograph form varied, minimum and peak flow rates and the total estimated transport capacity were held constant between runs. Armor ratios were estimated before and after runs by sampling the surface and subsurface separately. Armor behavior during runs was tracked by spray-painting the bed surface in three cross-sections that were repeatedly photographed then excavated after runs. Additional data collection during runs included photos for bed grain size

  2. The development of a fluidized bed process for the heat treatment of aluminum alloys

    NASA Astrophysics Data System (ADS)

    Keist, Jay

    2005-04-01

    Heat treating of aluminum alloys is often necessary to achieve the mechanical properties required for a part. With conventional furnaces, though, the heat-treating process requires several hours and manufacturers have traditionally utilized off-line, batch heat-treating operations. The long cycle times required for heat treating with conventional systems go contrary to lean manufacturing where the goal is to reduce the time a part spends in the factory. The fluidized bed technology offers rapid heating rates and excellent temperature control that allows one to significantly reduce the time required for heat treating by an order of magnitude. Technomics developed a fluidized bed conveying system that allows the manufacturer to bring the heat-treating system in-line with the casting or forging operation, obtaining a true lean manufacturing process.

  3. Speech Entrainment Compensates for Broca's Area Damage

    PubMed Central

    Fridriksson, Julius; Basilakos, Alexandra; Hickok, Gregory; Bonilha, Leonardo; Rorden, Chris

    2015-01-01

    Speech entrainment (SE), the online mimicking of an audiovisual speech model, has been shown to increase speech fluency in patients with Broca's aphasia. However, not all individuals with aphasia benefit from SE. The purpose of this study was to identify patterns of cortical damage that predict a positive response SE's fluency-inducing effects. Forty-four chronic patients with left hemisphere stroke (15 female) were included in this study. Participants completed two tasks: 1) spontaneous speech production, and 2) audiovisual SE. Number of different words per minute was calculated as a speech output measure for each task, with the difference between SE and spontaneous speech conditions yielding a measure of fluency improvement. Voxel-wise lesion-symptom mapping (VLSM) was used to relate the number of different words per minute for spontaneous speech, SE, and SE-related improvement to patterns of brain damage in order to predict lesion locations associated with the fluency-inducing response to speech entrainment. Individuals with Broca's aphasia demonstrated a significant increase in different words per minute during speech entrainment versus spontaneous speech. A similar pattern of improvement was not seen in patients with other types of aphasia. VLSM analysis revealed damage to the inferior frontal gyrus predicted this response. Results suggest that SE exerts its fluency-inducing effects by providing a surrogate target for speech production via internal monitoring processes. Clinically, these results add further support for the use of speech entrainment to improve speech production and may help select patients for speech entrainment treatment. PMID:25989443

  4. Array Processing for Radar Clutter Reduction and Imaging of Ice-Bed Interface

    NASA Astrophysics Data System (ADS)

    Gogineni, P.; Leuschen, C.; Li, J.; Hoch, A.; Rodriguez-Morales, F.; Ledford, J.; Jezek, K.

    2007-12-01

    A major challenge in sounding of fast-flowing glaciers in Greenland and Antarctica is surface clutter, which masks weak returns from the ice-bed interface. The surface clutter is also a major problem in sounding and imaging sub-surface interfaces on Mars and other planets. We successfully applied array-processing techniques to reduce clutter and image ice-bed interfaces of polar ice sheets. These techniques and tools have potential applications to planetary observations. We developed a radar with array-processing capability to measure thickness of fast-flowing outlet glaciers and image the ice-bed interface. The radar operates over the frequency range from 140 to 160 MHz with about an 800- Watt peak transmit power with transmit and receive antenna arrays. The radar is designed such that pulse width and duration are programmable. The transmit-antenna array is fed with a beamshaping network to obtain low sidelobes. We designed the receiver such that it can process and digitize signals for each element of an eight- channel array. We collected data over several fast-flowing glaciers using a five-element antenna array, limited by available hardpoints to mount antennas, on a Twin Otter aircraft during the 2006 field season and a four-element array on a NASA P-3 aircraft during the 2007 field season. We used both adaptive and non-adaptive signal-processing algorithms to reduce clutter. We collected data over the Jacobshavn Isbrae and other fast-flowing outlet glaciers, and successfully measured the ice thickness and imaged the ice-bed interface. In this paper, we will provide a brief description of the radar, discuss clutter-reduction algorithms, present sample results, and discuss the application of these techniques to planetary observations.

  5. The development of an integrated multistage fluid bed retorting process. [KENTORT II process--50-lb/hr

    SciTech Connect

    Carter, S.; Vego, A.; Taulbee, D.; Stehn, J.

    1992-01-01

    This report summarizes the progress made on the development of an integrated multistage fluidized bed retorting process (KENTORT II). The KENTORT II process includes integral fluidized bed zone for pyrolysis, gasification, and combustion of the oil shale. The purpose of this program is to design and test the KENTORT II process at the 50-lb/hr scale. The work performed during this year involved projects that will contribute physical and chemical data for the final design of the 50-lb/hr retort. A cold-flow model of the 50-lb/hr retort was built and tested. The unit demonstrated stable operation and proper fluidization of all beds. Good control of solid recirculation up to the maximum design rate for each loop (200 and 500 lb/hr, respectively) was achieved simultaneously. Basically, the cold-flow model is completely operational and translation of the cold-flow design parameters to the design of the retort is ready to begin. In another aspect of the program, a study of the cracking and coking kinetics of shale oil vapors passed over processed shales was initiated. The addition of a mass spectrometer to the system to monitor total carbon, nitrogen and sulfur evolution in real-time was successful. Coking activities of processed shales were ranked as follows: combusted shale > gasified shale > pyrolyzed shale. Arrangements for conducting an evaluation of KENTORT-derived oil for asphalt applications were finalized and testing was initiated.

  6. Analysis of fluidized bed granulation process using conventional and novel modeling techniques.

    PubMed

    Petrović, Jelena; Chansanroj, Krisanin; Meier, Brigitte; Ibrić, Svetlana; Betz, Gabriele

    2011-10-01

    Various modeling techniques have been applied to analyze fluidized-bed granulation process. Influence of various input parameters (product, inlet and outlet air temperature, consumption of liquid-binder, granulation liquid-binder spray rate, spray pressure, drying time) on granulation output properties (granule flow rate, granule size determined using light scattering method and sieve analysis, granules Hausner ratio, porosity and residual moisture) has been assessed. Both conventional and novel modeling techniques were used, such as screening test, multiple regression analysis, self-organizing maps, artificial neural networks, decision trees and rule induction. Diverse testing of developed models (internal and external validation) has been discussed. Good correlation has been obtained between the predicted and the experimental data. It has been shown that nonlinear methods based on artificial intelligence, such as neural networks, are far better in generalization and prediction in comparison to conventional methods. Possibility of usage of SOMs, decision trees and rule induction technique to monitor and optimize fluidized-bed granulation process has also been demonstrated. Obtained findings can serve as guidance to implementation of modeling techniques in fluidized-bed granulation process understanding and control. PMID:21839830

  7. Glacier beds that will be exposed in the future: How will geomorphologic and hydrologic processes develop?

    NASA Astrophysics Data System (ADS)

    Linsbauer, Andreas; Paul, Frank; Haeberli, Wilfried

    2014-05-01

    The rapid shrinkage of glaciers in the Alps has widespread impacts on relief development and hydrology. Slope failures, collapse of lateral moraines, loose debris in glacier fore-fields, new lakes and changing river beds are among the most visible impacts. They already require increased attention by tourists, monitoring by local authorities and mitigation measures (e.g. www.gletschersee.ch). A view into potential future developments (after glaciers have disappeared) is thus of high interest. With recently developed models that reconstruct glacier bed topography from easily available datasets (e.g. glacier outlines and a DEM) over entire mountain ranges, potential developments of the landscape and hydrology can be quantitatively determined. The modelled glacier beds - though they must be seen as a rough first order approximation only - also allows the investigation of a wide range of glaciological relations and dependencies that have been widely applied but were never investigated for a large sample of glaciers so far. A key reason is that information on glacier thickness distribution and total ice volume is sparse and that the future development of glaciers can only be modelled realistically when a glacier bed is available. Hence, with the glacier beds now available there is a larger number of geomorphological, glaciological and hydrological studies ahead of us. This presentation is providing an overview on the lessons learned about glaciers and their future development from the modelled glacier beds, the expected changes in hydrology (e.g. decreasing glacier volume and formation of new lakes) and potential impacts from the altered geomorphology (e.g. debuttressing of rock walls). In particular the flat tongues of larger valley glaciers are rather thick and leave oversteepened lateral moraines or rock walls behind, towering above overdeepenings in the glacier bed that might be filled with water. It is thus expected that the hazard potential will further increase in

  8. The role of hydrologic processes and geomorphology on the morphology and evolution of sediment clusters in gravel-bed rivers

    NASA Astrophysics Data System (ADS)

    Hendrick, Ross R.; Ely, Lisa L.; Papanicolaou, A. N.

    2010-01-01

    The effect of geomorphic features and hydraulic conditions on the formation, evolution, and morphology of sediment cluster microforms in an unregulated gravel-bed stream were investigated at field sites on the Entiat River, which drains the eastern slopes of the Cascade Mountains in central Washington state, USA. Sediment clusters were marked, described, and photographed before and after a series of moderate to high discharges over an 18-month period to quantify the evolution of the cluster morphologies. Individual sediment particles were tracked to calculate the range of flows and bed shear stresses that maintain and destroy clusters. Examination of geomorphic settings, channel morphology, and particle size distributions documented the conditions that favor cluster formation. The investigation tested the hypotheses that clusters in this environment delay sediment entrainment and that their morphology and evolution follow a predictable evolution similar to that found in laboratory studies. Clusters formed on gravel bars adjacent to riffles with slopes ≥ 1%, poor to moderate sorting, and mean and maximum particle size values 1.5 times greater than those associated with noncluster bars. Clusters were more stable under the bimodal sediment size distribution contributed by a tributary alluvial fan and were destroyed with and without anchor clast mobilization at sites where sediment size was more uniform. The six cluster morphologies identified in the field were similar to those in flume studies, but did not follow the same evolutionary cycle over multiple flow events. This contrast was attributed to the flow events resetting the cluster cycle, leading to a high percentage of upstream triangles. The dimensionless critical shear stress required to entrain the mean grain size ranged from 0.06 to 0.08. The hydraulic thresholds and geomorphic features that result in stable vs. mobilized cluster microforms in this setting can serve as a model for regulated rivers and

  9. Inversion of Bedding and Parasequence Types Preserved in Shelfal Mudstone Strata to Significant Marine Processes

    NASA Astrophysics Data System (ADS)

    Bohacs, K.; Lazar, R.; Demko, T.

    2012-12-01

    Mudstone strata contain an almost bewildering variety of physical, chemical, and biogenic attributes at the lamina to bed scale (mm - dm). Our observations of more than 7 km of Paleozoic to Pliocene mudstone revealed patterns in this variety of such macroscopic attributes as lithofacies, bedding, sedimentary structures, and stratal stacking patterns at the bedset to parasequence scale (cm - m). We quantified characteristics of each association and linked them to sets of depositional processes. Most shelfal mudstone strata appear to have accumulated in one of three end-member facies association successions (FASs) that can be related to physiographic settings and depositional regimes through characteristic modes of sediment transport and accumulation, as well as variations in benthic-energy and oxygen levels. FAS-1 comprises 1- to 10-meter-thick coarsening/thickening-upward stratal units, defined by lithologic indices: percent sandstone/siltstone/grainstone (Ss/Zs/Gs), maximum grain size, thickness of individual Ss/Zs/Gs bedsets. These FASs also have increasing total-organic-carbon content (TOC) and planktonic material in basal bedsets, overlain by an interval with an upward decrease in TOC and planktonic microfossil abundance along with an upward increase in skeletal phosphate, palynomorph content, and bioturbation. FAS-2 comprise 1- to 14-meter-thick coarsening/thickening-upward stratal units, defined by similar lithologic indices and changes as FAS-1; FAS-2 also has an upward decrease in content of TOC and planktonic microfossils, skeletal phosphate, and ichnofossil abundance and diversity. Very basal bedsets tend to have relatively low concentrations of planktonic material. Also distinctive are the common occurrence of palynodebris throughout (in post-Silurian rocks), with thin lags of macrofossils and skeletal phosphate in basal portions, Bouma B-C bedsets, and soft-sediment deformation with minimal, horizontal burrows in its middle portions, and scours, graded

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

    PubMed

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

    2006-06-16

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

  11. Industrial demonstration plant for the gasification of herb residue by fluidized bed two-stage process.

    PubMed

    Zeng, Xi; Shao, Ruyi; Wang, Fang; Dong, Pengwei; Yu, Jian; Xu, Guangwen

    2016-04-01

    A fluidized bed two-stage gasification process, consisting of a fluidized-bed (FB) pyrolyzer and a transport fluidized bed (TFB) gasifier, has been proposed to gasify biomass for fuel gas production with low tar content. On the basis of our previous fundamental study, an autothermal two-stage gasifier has been designed and built for gasify a kind of Chinese herb residue with a treating capacity of 600 kg/h. The testing data in the operational stable stage of the industrial demonstration plant showed that when keeping the reaction temperatures of pyrolyzer and gasifier respectively at about 700 °C and 850 °C, the heating value of fuel gas can reach 1200 kcal/Nm(3), and the tar content in the produced fuel gas was about 0.4 g/Nm(3). The results from this pilot industrial demonstration plant fully verified the feasibility and technical features of the proposed FB two-stage gasification process.

  12. Industrial demonstration plant for the gasification of herb residue by fluidized bed two-stage process.

    PubMed

    Zeng, Xi; Shao, Ruyi; Wang, Fang; Dong, Pengwei; Yu, Jian; Xu, Guangwen

    2016-04-01

    A fluidized bed two-stage gasification process, consisting of a fluidized-bed (FB) pyrolyzer and a transport fluidized bed (TFB) gasifier, has been proposed to gasify biomass for fuel gas production with low tar content. On the basis of our previous fundamental study, an autothermal two-stage gasifier has been designed and built for gasify a kind of Chinese herb residue with a treating capacity of 600 kg/h. The testing data in the operational stable stage of the industrial demonstration plant showed that when keeping the reaction temperatures of pyrolyzer and gasifier respectively at about 700 °C and 850 °C, the heating value of fuel gas can reach 1200 kcal/Nm(3), and the tar content in the produced fuel gas was about 0.4 g/Nm(3). The results from this pilot industrial demonstration plant fully verified the feasibility and technical features of the proposed FB two-stage gasification process. PMID:26849201

  13. THE SCALE-UP OF LARGE PRESSURIZED FLUIDIZED BEDS FOR ADVANCED COAL FIRED PROCESSES

    SciTech Connect

    Leon Glicksman; Hesham Younis; Richard Hing-Fung Tan; Michel Louge; Elizabeth Griffith; Vincent Bricout

    1998-04-30

    Pressurized fluidization is a promising new technology for the clean and efficient combustion of coal. Its principle is to operate a coal combustor at high inlet gas velocity to increase the flow of reactants, at an elevated pressure to raise the overall efficiency of the process. Unfortunately, commercialization of large pressurized fluidized beds is inhibited by uncertainties in scaling up units from the current pilot plant levels. In this context, our objective is to conduct a study of the fluid dynamics and solid capture of a large pressurized coal-fired unit. The idea is to employ dimensional similitude to simulate in a cold laboratory model the flow in a Pressurized Circulating Fluid Bed ''Pyrolyzer,'' which is part of a High Performance Power System (HIPPS) developed by Foster Wheeler Development Corporation (FWDC) under the DOE's Combustion 2000 program.

  14. Cortical entrainment to music and its modulation by expertise.

    PubMed

    Doelling, Keith B; Poeppel, David

    2015-11-10

    Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (<8 Hz; delta-theta) oscillations, similarly entrain to music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15-30 Hz)-often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition.

  15. Laboratory Experiments on Convective Entrainment Using a Saline Water Tank

    NASA Astrophysics Data System (ADS)

    Jonker, Harmen J. J.; Jiménez, Maria A.

    2014-06-01

    Entrainment fluxes in a shear-free convective boundary layer have been measured with a saline water tank set-up. The experiments were targeted towards measuring the entrainment behaviour for medium to high Richardson numbers and use a two-layer design, i.e. two stacked non-stratified (neutral) layers with different densities. With laser induced fluorescence (LIF), the entrainment flux of a fluorescent dye is measured for bulk Richardson numbers in the range 30-260. It is proposed that a carefully chosen combination of top-down and bottom-up processes improves the accuracy of LIF-based entrainment observations. The observed entrainment fluxes are about an order of magnitude lower than reported for thermal water tanks: the derived buoyancy entrainment ratio, , is found to be , which is to be compared with for a thermal convection tank (Deardorff et al., J Fluid Mech 100:41-64, 1980). An extensive discussion is devoted to the influence of the Reynolds and Prandtl numbers in laboratory experiments on entrainment.

  16. Cortical entrainment to music and its modulation by expertise.

    PubMed

    Doelling, Keith B; Poeppel, David

    2015-11-10

    Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (<8 Hz; delta-theta) oscillations, similarly entrain to music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15-30 Hz)-often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition. PMID:26504238

  17. Cortical entrainment to music and its modulation by expertise

    PubMed Central

    Doelling, Keith B.; Poeppel, David

    2015-01-01

    Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (<8 Hz; delta–theta) oscillations, similarly entrain to music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15–30 Hz)—often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition. PMID:26504238

  18. Method of removing sulfur emissions from a fluidized-bed combustion process

    DOEpatents

    Vogel, Gerhard John; Jonke, Albert A.; Snyder, Robert B.

    1978-01-01

    Alkali metal or alkaline earth metal oxides are impregnated within refractory support material such as alumina and introduced into a fluidized-bed process for the combustion of coal. Sulfur dioxide produced during combustion reacts with the metal oxide to form metal sulfates within the porous support material. The support material is removed from the process and the metal sulfate regenerated to metal oxide by chemical reduction. Suitable pore sizes are originally developed within the support material by heat-treating to accommodate both the sulfation and regeneration while still maintaining good particle strength.

  19. Rhythmic bedding in prodeltaic deposits of the ancient Colorado River: Exploring genetic processes

    NASA Astrophysics Data System (ADS)

    Waresak, Sandra; Nalin, Ronald; Lucarelli, Andrea

    2016-04-01

    Prodeltaic deposits represent a valuable archive for the characterization of deltaic depositional systems, offering a distal, minimally reworked record of dominant processes active at the fluvial-marine interface. The Fish Creek Basin (CA, US) preserves a ~ 3-km thick, lower Pliocene, progradational deltaic succession formed when the ancestral Colorado River infiltrated a marine rift basin (the early Gulf of California). The unit in this succession interpreted as prodeltaic, corresponding to the upper Mud Hills Member of the Deguynos Formation, consists of ~ 300 m of muddy siltstones. A striking attribute of parts of this unit is the presence of rhythmic bedding, with consistently alternating silt- to fine sand-dominated and clay-dominated beds forming couplets with an average thickness of 12 cm. By performing a detailed sedimentological analysis of the rhythmites and investigating periodicities in bed thickness, our study aimed at reconstructing the mode of deposition of this enigmatic prodeltaic succession. We measured at high stratigraphic resolution 265 consecutive couplets, for a total thickness of 33 m. Individual beds have good lateral persistence of at least tens of meters and gradational to sharp, flat contacts. Observed sedimentary structures are concentrated on the coarser portion of the couplets and mostly consist of parallel and wavy lamination, with subordinate ripple cross-lamination and localized internal scours. Bioturbation appears low in intensity or absent. Most notably, grain size analysis performed with laser diffraction techniques on several couplets shows a consistent pattern of inverse grading transitioning to normal grading. The cumulative evidence of these sedimentological features indicates that deposition of the rhythmites was accomplished via hyperpycnal flows, each couplet most likely representing an individual event in a setting characterized by high overall depositional rates. We performed time series analysis on bed thickness of

  20. Four stage, fluidized bed gasification process minimizes NO{sub x}

    SciTech Connect

    Lewis, F.M.; Haug, R.T.

    1999-07-01

    In 1981, after a long and thorough study of alternative methods of sewage sludge (biosolids) disposal, the City of Los Angeles (CLA) embarked on a pilot test program to incinerate dried sewage sludge from its Hyperion Wastewater Treatment Plant. This dried sludge is typically 47% ash, 53% combustible, and has an average higher heating value (HHV), moisture, ash-free (MAF) of 10,675 Btu/Lbm. The dried sludge is called sludge derived fuel (SDF). Approximately 8% of the MAF fraction of SDF is fuel-bound nitrogen. When SDF, with its extremely high fuel-bound nitrogen, was combusted in conventional multiple hearth and fluidized bed pilot plant furnaces, NO{sub x} emissions were extremely high ({gt}1,000 ppm). Faced with this dilemma, the CLA initiated an R and D program to reduce NO{sub x}. The pilot tests with a sub-stoichiometric fluid bed and an excess air afterburner (two-stages) reduced NO{sub x} to 400--600 ppm. With one intermediate stage added (three-stage), NO{sub x} was reduced to 130--150 ppm. However, when the following four-stage process was developed and tested, NO{sub x} was reduced to 50--75 ppm. Stage 1: Sub-stoichiometric fluidized bed operating at a nominal 30% stoichiometric air (SA). Stage 2:Sub-stoichiometric zone operating at a nominal 80% SA. Stage 3: Stoichiometric zone operating at a nominal 100% SA. Stage 4: Excess air zone (Afterburner) operating at a nominal 135% SA (35% excess air). After pilot testing was complete and design parameters established, three full-size, fluid bed gasifiers (two operational--one standby) were designed, constructed and operated until 1996. This paper describes the design, operation, and emission testing of these four-stage fluid bed gasifiers with special emphasis on the problems of (a) pneumatic feeding of SDF powder into the pressurized bed and (b) baghouse fabrics (expanded PTEE membrane on PTFE scrim). Final emission test results for NO{sub x} and other criteria pollutants are also presented.

  1. Flue gas cleanup using the Moving-Bed Copper Oxide Process

    SciTech Connect

    Pennline, Henry W; Hoffman, James S

    2013-10-01

    The use of copper oxide on a support had been envisioned as a gas cleanup technique to remove sulfur dioxide (SO{sub 2}) and nitric oxides (NO{sub x}) from flue gas produced by the combustion of coal for electric power generation. In general, dry, regenerable flue gas cleanup techniques that use a sorbent can have various advantages, such as simultaneous removal of pollutants, production of a salable by-product, and low costs when compared to commercially available wet scrubbing technology. Due to the temperature of reaction, the placement of the process into an advanced power system could actually increase the thermal efficiency of the plant. The Moving-Bed Copper Oxide Process is capable of simultaneously removing sulfur oxides and nitric oxides within the reactor system. In this regenerable sorbent technique, the use of the copper oxide sorbent was originally in a fluidized bed, but the more recent effort developed the use of the sorbent in a moving-bed reactor design. A pilot facility or life-cycle test system was constructed so that an integrated testing of the sorbent over absorption/regeneration cycles could be conducted. A parametric study of the total process was then performed where all process steps, including absorption and regeneration, were continuously operated and experimentally evaluated. The parametric effects, including absorption temperature, sorbent and gas residence times, inlet SO{sub 2} and NO{sub x} concentration, and flyash loadings, on removal efficiencies and overall operational performance were determined. Although some of the research results have not been previously published because of previous collaborative restrictions, a summary of these past findings is presented in this communication. Additionally, the potential use of the process for criteria pollutant removal in oxy-firing of fossil fuel for carbon sequestration purposes is discussed.

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

    PubMed

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

    2015-12-30

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

  3. The role of vegetation and bed-level fluctuations in the process of channel narrowing

    USGS Publications Warehouse

    Friedman, J.M.; Osterkamp, W.R.; Lewis, W.M.

    1996-01-01

    A catastrophic flood in 1965 on Plum Creek, a perennial sandbed stream in the western Great Plains, removed most of the bottomland vegetation and transformed the single-thalweg stream into a wider, braided channel. Following eight years of further widening associated with minor high flows, a process of channel narrowing began in 1973; narrowing continues today. The history of channel narrowing was reconstructed by counting the annual rings of 129 trees and shrubs along a 5-km reach of Plum Creek near Louviers, Colorado. Sixty-three of these plants were excavated in order to determine the age and elevation of the germination point. The reconstructed record of channel change was verified from historical aerial photographs, and then compared to sediment stratigraphy and records of discharge and bed elevation from a streamflow gaging station in the study reach. Channel narrowing at Plum Creek occurs in two ways. First, during periods of high flow, sand and fine gravel are delivered to the channel, temporarily raising the general bed-level. Subsequently, several years of uninterrupted low flows incise a narrower channel. Second, during years of low flow, vegetation becomes established on the subaerial part of the present channel bed. In both cases, surfaces stabilize as a result of vegetation growth and vertical accretion of sediment.

  4. Chemical looping combustion in a rotating bed reactor--finding optimal process conditions for prototype reactor.

    PubMed

    Håkonsen, Silje Fosse; Blom, Richard

    2011-11-15

    A lab-scale rotating bed reactor for chemical looping combustion has been designed, constructed, and tested using a CuO/Al(2)O(3) oxygen carrier and methane as fuel. Process parameters such as bed rotating frequency, gas flows, and reactor temperature have been varied to find optimal performance of the prototype reactor. Around 90% CH(4) conversion and >90% CO(2) capture efficiency based on converted methane have been obtained. Stable operation has been accomplished over several hours, and also--stable operation can be regained after intentionally running into unstable conditions. Relatively high gas velocities are used to avoid fully reduced oxygen carrier in part of the bed. Potential CO(2) purity obtained is in the range 30 to 65%--mostly due to air slippage from the air sector--which seems to be the major drawback of the prototype reactor design. Considering the prototype nature of the first version of the rotating reactor setup, it is believed that significant improvements can be made to further avoid gas mixing in future modified and up-scaled reactor versions.

  5. Melt granulation of pharmaceutical powders: a comparison of high-shear mixer and fluidised bed processes.

    PubMed

    Passerini, Nadia; Calogerà, Giacomo; Albertini, Beatrice; Rodriguez, Lorenzo

    2010-05-31

    The main aim of this research was to compare in situ melt granulation process in high-shear mixers and fluidised bed equipments with particular attention to the final properties of granules. In addition, the study evaluated the suitability of melt granulation in fluidised bed for improving the dissolution rate of drugs. Agglomerates having identical composition (10%, w/w, of ibuprofen or ketoprofen, 20%, w/w, of PEG 6000 and 70%, w/w, of lactose monohydrate) were produced using both equipments and their morphology, particle size, flowability, friability, drug loading, dissolution behaviors at pH 1.2 and 7.4 and physicochemical properties (DSC and XRD analysis) have been evaluated and compared. The results showed that melt granulation can be successfully performed in both granulators. The utilization of a different equipment had strong impact on the particle size distribution of the granules and on their morphology, while the effect on others physical properties was little, as all the granules possess low friability and excellent flowability. Moreover both the solid state characteristics of the products and the dissolution behaviors of ibuprofen and ketoprofen granules were found to be practically independent of the equipment and all granules showed a significant increase of the drug dissolution rate in acidic conditions. In conclusion in situ melt granulation in fluidised beds could be considered a suitable alternative to the melt granulation in high-shear mixers. PMID:20214959

  6. Vistula River bed erosion processes and their influence on Warsaw's flood safety

    NASA Astrophysics Data System (ADS)

    Magnuszewski, A.; Moran, S.

    2015-03-01

    Large cities have historically been well protected against floods as a function of their importance to society. In Warsaw, Poland, located on a narrow passage of the Vistula River valley, urban flood disasters were not unusual. Beginning at the end of the 19th century, the construction of river embankment and training works caused the narrowing of the flood passage path in the downtown reach of the river. The process of bed erosion lowered the elevation of the river bed by 205 cm over the 20th century, and the consequences of bed lowering are reflected by the rating curve change. Conditions of the flood passage have been analysed by the CCHE2D hydrodynamic model both in retro-modelling and scenario simulation modelling. The high water mark of the 1844 flood and iterative calculations in retro-modelling made possible estimation of the discharge, Q = 8250 m3 s-1. This highest observed historical flood in a natural river has been compared to recent conditions of the Vistula River in Warsaw by scenario modelling. The result shows dramatic changes in water surface elevation, velocities, and shear stress. The vertical velocity in the proximity of Port Praski gauge at km 513 can reach 3.5 m s-1, a very high value for a lowland river. The average flow conveyance is improving due to channel erosion but also declining in the case of extreme floods due to high resistance from vegetation on the flood plains.

  7. Measurement of air entrainment in plasma jets

    NASA Astrophysics Data System (ADS)

    Fincke, J. R.; Rodriquez, R.; Pentecost, C. G.

    The concentration and temperature of air entrained into argon and helium plasma jets has been measured using coherent anti-Stokes Raman spectroscopy (CARS). The argon plasma flow field is characterized by a short region of well behaved laminar flow near the nozzle exit followed by an abrupt transition to turbulence. Once the transition of turbulence occurs, air is rapidly mixed into the jet core. The location of the transition region is determined by the rapid cooling of the jet and the resulting increase in Reynolds number. In contrast, the helium plasma flow field never exceeds a Reynolds number of 200 and remains laminar. The entrainment process in this case is controlled by molecular diffusion rather than turbulent mixing.

  8. Measurement of air entrainment in plasma jets

    SciTech Connect

    Fincke, J.R.; Rodriquez, R.; Pentecost, C.G.

    1990-01-01

    The concentration and temperature of air entrained into argon and helium plasma jets has been measured using coherent anti-Stokes Raman spectroscopy (CARS). The argon plasma flow field is characterized by a short region of well behaved laminar flow near the nozzle exit followed by an abrupt transition to turbulence. Once the transition of turbulence occurs, air is rapidly mixed into the jet core. The location of the transition region is determined by the rapid cooling of the jet and the resulting increase in Reynolds number. In contrast, the helium plasma flow field never exceeds a Reynolds number of 200 and remains laminar. The entrainment process in this case is controlled by molecular diffusion rather than turbulent mixing. 9 refs., 5 figs., 1 tab.

  9. Effects of process parameters on solid self-microemulsifying particles in a laboratory scale fluid bed.

    PubMed

    Mukherjee, Tusharmouli; Plakogiannis, Fotios M

    2012-01-01

    The purpose of this study was to select the critical process parameters of the fluid bed processes impacting the quality attribute of a solid self-microemulsifying (SME) system of albendazole (ABZ). A fractional factorial design (2(4-1)) with four parameters (spray rate, inlet air temperature, inlet air flow, and atomization air pressure) was created by MINITAB software. Batches were manufactured in a laboratory top-spray fluid bed at 625-g scale. Loss on drying (LOD) samples were taken throughout each batch to build the entire moisture profiles. All dried granulation were sieved using mesh 20 and analyzed for particle size distribution (PSD), morphology, density, and flow. It was found that as spray rate increased, sauter-mean diameter (D(s)) also increased. The effect of inlet air temperature on the peak moisture which is directly related to the mean particle size was found to be significant. There were two-way interactions between studied process parameters. The main effects of inlet air flow rate and atomization air pressure could not be found as the data were inconclusive. The partial least square (PLS) regression model was found significant (P < 0.01) and predictive for optimization. This study established a design space for the parameters for solid SME manufacturing process.

  10. Flicker Regularity Is Crucial for Entrainment of Alpha Oscillations

    PubMed Central

    Notbohm, Annika; Herrmann, Christoph S.

    2016-01-01

    compared to those presented during the maximum. In the second experiment stimulation with higher light intensity during both rhythmic and arrhythmic stimulation lead to an increased behavioral modulation depth, supposedly as a consequence of stronger entrainment during rhythmic stimulation. Altogether, our results reveal evidence for rhythmic and arrhythmic visual stimulation to induce fundamentally different processes in the brain: we suggest that rhythmic but not arrhythmic stimulation interacts with ongoing alpha oscillations via entrainment. PMID:27790105

  11. Vortex shedding and morphodynamic response of bed surfaces containing non-erodible roughness elements

    NASA Astrophysics Data System (ADS)

    McKenna Neuman, Cheryl; Sanderson, Robert Steven; Sutton, Stephen

    2013-09-01

    A series of wind tunnel experiments was carried out to investigate particle entrainment from surfaces in which one or more roughness elements were embedded. Thin sand strips were employed to eliminate impact and ejection, and thus isolate entrainment by fluid drag. The pattern of erosion is consistent with the presence of coherent vortices, inclusive of trailing vortices in the wake flow. The shape and orientation of the roughness element strongly influence this pattern. When an upwind supply of saltators is introduced, the majority of particles within the bed are entrained through impact, with the exception of a sand tail to the lee of the roughness element. That is, the effect of coherent structures within the airflow, as related to spatial variation in the fluid drag exerted on the bed surface, is completely overprinted by the saltation cloud and the blocking of particle trajectories by the upwind face of the roughness element. In a repeated set of experiments, the bed was allowed to fully adjust its morphology to the transport system. In this case, particle entrainment did not selectively occur within the zone of wake flow, and by inference the fluid stress across the test surface appeared to be uniform. These experiments support the hypothesis that vortex annihilation occurs on morphodynamically adjusted surfaces. In summary, the system response to the emergence of non-erodible roughness elements on surfaces affected by wind erosion involves a suite of geophysical processes, each of which attains varied levels of dominance within a given morphodynamic domain.

  12. Applicability of fluidized bed reactor in recalcitrant compound degradation through advanced oxidation processes: a review.

    PubMed

    Tisa, Farhana; Abdul Raman, Abdul Aziz; Wan Daud, Wan Mohd Ashri

    2014-12-15

    Treatment of industrial waste water (e.g. textile waste water, phenol waste water, pharmaceutical etc) faces limitation in conventional treatment procedures. Advanced oxidation processes (AOPs) do not suffer from the limits of conventional treatment processes and consequently degrade toxic pollutants more efficiently. Complexity is faced in eradicating the restrictions of AOPs such as sludge formation, toxic intermediates formation and high requirement for oxidants. Increased mass-transfer in AOPs is an alternate solution to this problem. AOPs combined with Fluidized bed reactor (FBR) can be a potential choice compared to fixed bed or moving bed reactor, as AOP catalysts life-span last for only maximum of 5-10 cycles. Hence, FBR-AOPs require lesser operational and maintenance cost by reducing material resources. The time required for AOP can be minimized using FBR and also treatable working volume can be increased. FBR-AOP can process from 1 to 10 L of volume which is 10 times more than simple batch reaction. The mass transfer is higher thus the reaction time is lesser. For having increased mass transfer sludge production can be successfully avoided. The review study suggests that, optimum particle size, catalyst to reactor volume ratio, catalyst diameter and liquid or gas velocity is required for efficient FBR-AOP systems. However, FBR-AOPs are still under lab-scale investigation and for industrial application cost study is needed. Cost of FBR-AOPs highly depends on energy density needed and the mechanism of degradation of the pollutant. The cost of waste water treatment containing azo dyes was found to be US$ 50 to US$ 500 per 1000 gallons where, the cost for treating phenol water was US$ 50 to US$ 800 per 1000 gallons. The analysis for FBR-AOP costs has been found to depend on the targeted pollutant, degradation mechanism (zero order, 1st order and 2nd order) and energy consumptions by the AOPs.

  13. Applicability of fluidized bed reactor in recalcitrant compound degradation through advanced oxidation processes: a review.

    PubMed

    Tisa, Farhana; Abdul Raman, Abdul Aziz; Wan Daud, Wan Mohd Ashri

    2014-12-15

    Treatment of industrial waste water (e.g. textile waste water, phenol waste water, pharmaceutical etc) faces limitation in conventional treatment procedures. Advanced oxidation processes (AOPs) do not suffer from the limits of conventional treatment processes and consequently degrade toxic pollutants more efficiently. Complexity is faced in eradicating the restrictions of AOPs such as sludge formation, toxic intermediates formation and high requirement for oxidants. Increased mass-transfer in AOPs is an alternate solution to this problem. AOPs combined with Fluidized bed reactor (FBR) can be a potential choice compared to fixed bed or moving bed reactor, as AOP catalysts life-span last for only maximum of 5-10 cycles. Hence, FBR-AOPs require lesser operational and maintenance cost by reducing material resources. The time required for AOP can be minimized using FBR and also treatable working volume can be increased. FBR-AOP can process from 1 to 10 L of volume which is 10 times more than simple batch reaction. The mass transfer is higher thus the reaction time is lesser. For having increased mass transfer sludge production can be successfully avoided. The review study suggests that, optimum particle size, catalyst to reactor volume ratio, catalyst diameter and liquid or gas velocity is required for efficient FBR-AOP systems. However, FBR-AOPs are still under lab-scale investigation and for industrial application cost study is needed. Cost of FBR-AOPs highly depends on energy density needed and the mechanism of degradation of the pollutant. The cost of waste water treatment containing azo dyes was found to be US$ 50 to US$ 500 per 1000 gallons where, the cost for treating phenol water was US$ 50 to US$ 800 per 1000 gallons. The analysis for FBR-AOP costs has been found to depend on the targeted pollutant, degradation mechanism (zero order, 1st order and 2nd order) and energy consumptions by the AOPs. PMID:25190594

  14. The use of fixed bed absorbents for flexible operation on the SAGE gas processing plant

    SciTech Connect

    Carnell, P.J.H.; Joslin, K.W.; Woodham, P.R.

    1995-11-01

    Mobil North Sea Ltd. operates the SAGE Gas Terminal at St. Fergus, Scotland on behalf of the SAGE partners. This terminal is capable of processing 1,150 MMscfd of sour gas with the sales gas being delivered into the British Gas distribution network and NGL`s exported by pipelines to Shell`s NGL fractionation plant at Mossmorran and BP`s fractionation plant at Kinneil. In order to meet the specifications for the sales gas and NGL produced while processing different mixtures of three separate feed gases produced by three independently operated production platforms the SAGE Gas Terminal has utilized ICI Katalco`s PURASPEC{trademark} processes to provide flexibility and reduce cost. This paper discusses how and where these fixed bed processes are utilized.

  15. Mechanisms of granular activated carbon anaerobic fluidized-bed process for treating phenols wastewater.

    PubMed

    Lao, Shan-gen

    2002-01-01

    Granular activated carbon (GAC) anaerobic fluidized-bed reactor was applied to treating phenols wastewater. When influent phenol concentration was 1000 mg/L, volume loadings of phenol and CODCr were 0.39 kg/(m3.d) and 0.98 kg/(m3.d), their removal rates were 99.9% and 96.4% respectively. From analyzing above results, the main mechanisms of the process are that through fluidizing GAC, its adsorption is combined with biodegradation, both activities are brought into full play, and phenol in wastewater is effectively decomposed. Meanwhile problems concerning gas-liquid separation and medium plugging are well solved. PMID:11887310

  16. A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes

    NASA Technical Reports Server (NTRS)

    Fridlin, Ann; vanDiedenhoven, Bastiaan; Ackerman, Andrew S.; Avramov, Alexander; Mrowiec, Agnieszka; Morrison, Hugh; Zuidema, Paquita; Shupe, Matthew D.

    2012-01-01

    Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)Arctic Cloud Experiment (ACE)Surface Heat Budget of the Arctic Ocean (SHEBA) campaign provide a unique opportunity to test understanding of cloud ice formation. Under the microphysically simple conditions observed (apparently negligible ice aggregation, sublimation, and multiplication), the only expected source of new ice crystals is activation of heterogeneous ice nuclei (IN) and the only sink is sedimentation. Large-eddy simulations with size-resolved microphysics are initialized with IN number concentration N(sub IN) measured above cloud top, but details of IN activation behavior are unknown. If activated rapidly (in deposition, condensation, or immersion modes), as commonly assumed, IN are depleted from the well-mixed boundary layer within minutes. Quasi-equilibrium ice number concentration N(sub i) is then limited to a small fraction of overlying N(sub IN) that is determined by the cloud-top entrainment rate w(sub e) divided by the number-weighted ice fall speed at the surface v(sub f). Because w(sub c)< 1 cm/s and v(sub f)> 10 cm/s, N(sub i)/N(sub IN)<< 1. Such conditions may be common for this cloud type, which has implications for modeling IN diagnostically, interpreting measurements, and quantifying sensitivity to increasing N(sub IN) (when w(sub e)/v(sub f)< 1, entrainment rate limitations serve to buffer cloud system response). To reproduce observed ice crystal size distributions and cloud radar reflectivities with rapidly consumed IN in this case, the measured above-cloud N(sub IN) must be multiplied by approximately 30. However, results are sensitive to assumed ice crystal properties not constrained by measurements. In addition, simulations do not reproduce the pronounced mesoscale heterogeneity in radar reflectivity that is observed.

  17. Process development and modeling of fluidized-bed reactor with coimmobilized biocatalyst for fuel ethanol production

    NASA Astrophysics Data System (ADS)

    Sun, May Yongmei

    This research focuses on two steps of commercial fuel ethanol production processes: the hydrolysis starch process and the fermentation process. The goal of this research is to evaluate the performance of co-immobilized biocatalysts in a fluidized bed reactor with emphasis on economic and engineering aspects and to develop a predictive mathematical model for this system. The productivity of an FBR is higher than productivity of a traditional batch reactor or CSTR. Fluidized beds offer great advantages over packed beds for immobilized cells when small particles are used or when the reactant feed contains suspended solids. Plugging problems, excessive pressure drops (and thus attrition), or crushing risks may be avoided. No mechanical stirring is required as mixing occurs due to the natural turbulence in the fluidized process. Both enzyme and microorganism are immobilized in one catalyst bead which is called co-immobilization. Inside this biocatalyst matrix, starch is hydrolyzed by the enzyme glucoamylase to form glucose and then converted to ethanol and carbon dioxide by microorganisms. Two biocatalysts were evaluated: (1) co-immobilized yeast strain Saccharomyces cerevisiae and glucoamylase. (2) co-immobilized Zymomonas mobilis and glucoamylase. A co-immobilized biocatalyst accomplishes the simultaneous saccharification and fermentation (SSF process). When compared to a two-step process involving separate saccharification and fermentation stages, the SSF process has productivity values twice that given by the pre-saccharified process when the time required for pre-saccharification (15--25 h) was taken into account. The SSF process should also save capital cost. The information about productivity, fermentation yield, concentration profiles along the bed, ethanol inhibition, et al., was obtained from the experimental data. For the yeast system, experimental results showed that: no apparent decrease of productivity occurred after two and half months, the productivity

  18. Process Analysis of Lignite Circulating Fluidized Bed Boiler Coupled with Pyrolysis Topping

    NASA Astrophysics Data System (ADS)

    Wang, Baoqun; Dong, Li; Wang, Yin; Matsuzawa, Y.; Xu, Guangwen

    We developed a comprehensive process model in ASPEN Plus to simulate the energy and mass balances of a lignite-fueled atmospheric circulating fluidized bed (CFB) boiler integrated with coal predrying and pyrolysis topping. In this model, it is assumed that the heat from exhausted flue gas was employed for coal predrying, and the sensible heat derived from circulated bed material was used for the pyrolysis topping (endothermic process). The simulation was conducted with respectto the Yunnan Kaiyuan CFB boiler, and two representative lignite coals from Xiao Long Tan (XLT) and Xin Shao (XS) were considered. The result shows that the predrying of coal with the sensible heat of above 363 K from flue gas, the amount of coal consumed in the boiler can be reduced by 3.5% and 5.3% for XLT lignite and XS lignite, respectively. It was also found that integration of pyrolysis topping with the boiler increased the coal consumption of the boiler, and the extent of consumption-increase varies with the yields of tar and gas in the pyrolysis topping process. For agas yield of 5.2% and a tar yield of 5-6%, the consumption of XS lignite increased by about 20% comparing to that in the case without topping.

  19. Performance analysis of RDF gasification in a two stage fluidized bed-plasma process.

    PubMed

    Materazzi, M; Lettieri, P; Taylor, R; Chapman, C

    2016-01-01

    The major technical problems faced by stand-alone fluidized bed gasifiers (FBG) for waste-to gas applications are intrinsically related to the composition and physical properties of waste materials, such as RDF. The high quantity of ash and volatile material in RDF can provide a decrease in thermal output, create high ash clinkering, and increase emission of tars and CO2, thus affecting the operability for clean syngas generation at industrial scale. By contrast, a two-stage process which separates primary gasification and selective tar and ash conversion would be inherently more forgiving and stable. This can be achieved with the use of a separate plasma converter, which has been successfully used in conjunction with conventional thermal treatment units, for the ability to 'polish' the producer gas by organic contaminants and collect the inorganic fraction in a molten (and inert) state. This research focused on the performance analysis of a two-stage fluid bed gasification-plasma process to transform solid waste into clean syngas. Thermodynamic assessment using the two-stage equilibrium method was carried out to determine optimum conditions for the gasification of RDF and to understand the limitations and influence of the second stage on the process performance (gas heating value, cold gas efficiency, carbon conversion efficiency), along with other parameters. Comparison with a different thermal refining stage, i.e. thermal cracking (via partial oxidation) was also performed. The analysis is supported by experimental data from a pilot plant.

  20. Performance analysis of RDF gasification in a two stage fluidized bed-plasma process.

    PubMed

    Materazzi, M; Lettieri, P; Taylor, R; Chapman, C

    2016-01-01

    The major technical problems faced by stand-alone fluidized bed gasifiers (FBG) for waste-to gas applications are intrinsically related to the composition and physical properties of waste materials, such as RDF. The high quantity of ash and volatile material in RDF can provide a decrease in thermal output, create high ash clinkering, and increase emission of tars and CO2, thus affecting the operability for clean syngas generation at industrial scale. By contrast, a two-stage process which separates primary gasification and selective tar and ash conversion would be inherently more forgiving and stable. This can be achieved with the use of a separate plasma converter, which has been successfully used in conjunction with conventional thermal treatment units, for the ability to 'polish' the producer gas by organic contaminants and collect the inorganic fraction in a molten (and inert) state. This research focused on the performance analysis of a two-stage fluid bed gasification-plasma process to transform solid waste into clean syngas. Thermodynamic assessment using the two-stage equilibrium method was carried out to determine optimum conditions for the gasification of RDF and to understand the limitations and influence of the second stage on the process performance (gas heating value, cold gas efficiency, carbon conversion efficiency), along with other parameters. Comparison with a different thermal refining stage, i.e. thermal cracking (via partial oxidation) was also performed. The analysis is supported by experimental data from a pilot plant. PMID:26184896

  1. Air entrainment in hairy surfaces

    NASA Astrophysics Data System (ADS)

    Nasto, Alice; Regli, Marianne; Brun, P.-T.; Alvarado, José; Clanet, Christophe; Hosoi, A. E.

    2016-07-01

    Motivated by diving semiaquatic mammals, we investigate the mechanism of dynamic air entrainment in hairy surfaces submerged in liquid. Hairy surfaces are cast out of polydimethylsiloxane elastomer and plunged into a fluid bath at different velocities. Experimentally, we find that the amount of air entrained is greater than what is expected for smooth surfaces. Theoretically, we show that the hairy surface can be considered as a porous medium and we describe the air entrainment via a competition between the hydrostatic forcing and the viscous resistance in the pores. A phase diagram that includes data from our experiments and biological data from diving semiaquatic mammals is included to place the model system in a biological context and predict the regime for which the animal is protected by a plastron of air.

  2. Synthesis of Entrainment and Detrainment formulations for Convection Parameterizations

    NASA Astrophysics Data System (ADS)

    Siebesma, P.

    2015-12-01

    Mixing between convective clouds and its environment, usually parameterized in terms of entrainment and detrainment, are among the most important processes that determine the strength of the climate model sensitivity. This notion has led to a renaissance of research in exploring the mechanisms of these mixing processes and, as a result, to a wide range of seemingly different parameterized formulations. In this study we are aiming to synthesize these results as to offer a solid framework for use in parameterized formulations of convection. Detailed LES analyses in which clouds are subsampled according to their size show that entrainment rates are inversely proportional to the typical cloud radius, in accordance with original entraining plume models. These results can be shown analytically to be consistent with entrainment rate formulations of cloud ensembles that decrease inversely proportional with height, by making only mild assumptions on the shape of the associated cloud size distribution. In addition there are additional dependencies of the entrainment rates on the environmental thermodynamics such as the relative humidity and stability but these are of second order. In contrast detrainment rates do depend to first order on the environmental thermodynamics such as relative humidity and stability. This can be understood by realizing that i) the details of the cloud size distribution do depend on these environmental factors and ii) that detrainment rates have a much stronger dependency on the shape of the cloud size distribution than entrainment rates.

  3. Fluidized bed gasification of industrial solid recovered fuels.

    PubMed

    Arena, Umberto; Di Gregorio, Fabrizio

    2016-04-01

    The study evaluates the technical feasibility of the fluidized bed gasification of three solid recovered fuels (SRFs), obtained as co-products of a recycling process. The SRFs were pelletized and fed to a pilot scale bubbling fluidized bed reactor, operated in gasification and co-gasification mode. The tests were carried out under conditions of thermal and chemical steady state, with a bed of olivine particles and at different values of equivalence ratio. The results provide a complete syngas characterization, in terms of its heating value and composition (including tars, particulates, and acid/basic pollutants) and of the chemical and physical characterization of bed material and entrained fines collected at the cyclone outlet. The feasibility of the fluidized bed gasification process of the different SRFs was evaluated with the support of a material and substance flow analysis, and a feedstock energy analysis. The results confirm the flexibility of fluidized bed reactor, which makes it one of the preferable technologies for the gasification of different kind of wastes, even in co-gasification mode. The fluidized bed gasification process of the tested SRFs appears technically feasible, yielding a syngas of valuable quality for energy applications in an appropriate plant configuration. PMID:26896004

  4. Fluidized bed gasification of industrial solid recovered fuels.

    PubMed

    Arena, Umberto; Di Gregorio, Fabrizio

    2016-04-01

    The study evaluates the technical feasibility of the fluidized bed gasification of three solid recovered fuels (SRFs), obtained as co-products of a recycling process. The SRFs were pelletized and fed to a pilot scale bubbling fluidized bed reactor, operated in gasification and co-gasification mode. The tests were carried out under conditions of thermal and chemical steady state, with a bed of olivine particles and at different values of equivalence ratio. The results provide a complete syngas characterization, in terms of its heating value and composition (including tars, particulates, and acid/basic pollutants) and of the chemical and physical characterization of bed material and entrained fines collected at the cyclone outlet. The feasibility of the fluidized bed gasification process of the different SRFs was evaluated with the support of a material and substance flow analysis, and a feedstock energy analysis. The results confirm the flexibility of fluidized bed reactor, which makes it one of the preferable technologies for the gasification of different kind of wastes, even in co-gasification mode. The fluidized bed gasification process of the tested SRFs appears technically feasible, yielding a syngas of valuable quality for energy applications in an appropriate plant configuration.

  5. Modified graphical autocatalytic set model of combustion process in circulating fluidized bed boiler

    NASA Astrophysics Data System (ADS)

    Yusof, Nurul Syazwani; Bakar, Sumarni Abu; Ismail, Razidah

    2014-07-01

    Circulating Fluidized Bed Boiler (CFB) is a device for generating steam by burning fossil fuels in a furnace operating under a special hydrodynamic condition. Autocatalytic Set has provided a graphical model of chemical reactions that occurred during combustion process in CFB. Eight important chemical substances known as species were represented as nodes and catalytic relationships between nodes are represented by the edges in the graph. In this paper, the model is extended and modified by considering other relevant chemical reactions that also exist during the process. Catalytic relationship among the species in the model is discussed. The result reveals that the modified model is able to gives more explanation of the relationship among the species during the process at initial time t.

  6. Quantifying entrainment in pyroclastic density currents from the Tungurahua eruption, Ecuador: Integrating field proxies with numerical simulations

    NASA Astrophysics Data System (ADS)

    Benage, M. C.; Dufek, J.; Mothes, P. A.

    2016-07-01

    The entrainment of air into pyroclastic density currents (PDCs) impacts the dynamics and thermal history of these highly mobile currents. However, direct measurement of entrainment in PDCs is hampered due to hazardous conditions and opaqueness of these flows. We combine three-dimensional multiphase Eulerian-Eulerian-Lagrangian calculations with proxies of thermal conditions preserved in deposits to quantify air entrainment in PDCs at Tungurahua volcano, Ecuador. We conclude that small-volume PDCs develop a particle concentration gradient that results in disparate thermal characteristics for the concentrated bed load (>600 to ~800 K) and the overlying dilute suspended load (~300-600 K). The dilute suspended load has effective entrainment coefficients 2-3 times larger than the bed load. This investigation reveals a dichotomy in entrainment and thermal history between two regions in the current and provides a mechanism to interpret the depositional thermal characteristics of small-volume but frequently occurring PDCs.

  7. Chemical effect of entrained particles in coal conversion streams. Sixth quarterly technical progress report, November 1, 1982-January 31, 1983

    SciTech Connect

    Stinespring, C.; Yousefian, V.; Gruninger, J.; Annen, K.; Frankel, D.; Stewart, G.

    1983-01-01

    A major objective of the US Department of Energy is to increase coal utilization through the development of combustion stream cleanup technologies. Many of the existing cleanup devices as well as advanced concepts rely on heterogeneous processes (i.e., gas-solid interactions) to achieve efficient stream removal. Examples of such devices include particle injection and granular bed filters for alkali removal, limestone injection for SO/sub x/ removal in fluid bed combustors, dry injection for SO/sub x/removal in entrained combustion, and trace metal adsorption and removal on fly ash. Recent studies indicate that the successful use of turbines in combined cycle processes may depend on understanding the interaction between the gas phase alkali and particles in the combustion stream to substantially reduce turbine corrosion. This report documents progress in efforts to model the heterogeneous chemistry of coal combustion streams as well as laboratory studies to obtain critical input data for the report. 5 references, 15 figures.

  8. Proof-of-concept testing of fluidized-bed copper oxide process

    SciTech Connect

    Gala, H.B.

    1992-01-01

    The objective of Phase IV of the contract is to design a conceptual flue gas treating unit based on the fluidized-bed copper oxide (FBCO) process for a new coal-fired 500 MW(e) power plant. A technical and economic evaluation of the FBCO process that is based on the conceptual design will also be completed. The scope of the work during this reporting period was limited to Task 4.0, Proposal review and negotiations, and Task 4.1, Definition of design basis. In the revised Statement of Work (SO/At) for Phase IV, a cold-circulation dense-phase testing of the sorbent material is proposed. Presently, UOP does not manufacture the sorbents, SOX-3 and SOX-4, that were used in the life-cycle testing of the fluidized-bed copper oxide unit at PETC. So as an alternative to the sorbent, UOP proposed that the alumina support be used In the cold-circulation tests. Under Task 4.1, the feasibility of using the support material was evaluated in a series of attrition tests conducted on the SOX-3 sorbent and the alumina support. The testing took place during this reporting period. The objective of these tests was to examine the relative strength of the two materials.

  9. Examination of turbulent entrainment-mixing mechanisms using a combined approach

    SciTech Connect

    Lu, C.; Liu, Y.; Niu, S.

    2011-10-01

    Turbulent entrainment-mixing mechanisms are investigated by applying a combined approach to the aircraft measurements of three drizzling and two nondrizzling stratocumulus clouds collected over the U.S. Department of Energy's Atmospheric Radiation Measurement Southern Great Plains site during the March 2000 cloud Intensive Observation Period. Microphysical analysis shows that the inhomogeneous entrainment-mixing process occurs much more frequently than the homogeneous counterpart, and most cases of the inhomogeneous entrainment-mixing process are close to the extreme scenario, having drastically varying cloud droplet concentration but roughly constant volume-mean radius. It is also found that the inhomogeneous entrainment-mixing process can occur both near the cloud top and in the middle level of a cloud, and in both the nondrizzling clouds and nondrizzling legs in the drizzling clouds. A new dimensionless number, the scale number, is introduced as a dynamical measure for different entrainment-mixing processes, with a larger scale number corresponding to a higher degree of homogeneous entrainment mixing. Further empirical analysis shows that the scale number that separates the homogeneous from the inhomogeneous entrainment-mixing process is around 50, and most legs have smaller scale numbers. Thermodynamic analysis shows that sampling average of filament structures finer than the instrumental spatial resolution also contributes to the dominance of inhomogeneous entrainment-mixing mechanism. The combined microphysical-dynamical-thermodynamic analysis sheds new light on developing parameterization of entrainment-mixing processes and their microphysical and radiative effects in large-scale models.

  10. Biomass Torrefaction Process Review and Moving Bed Torrefaction System Model Development

    SciTech Connect

    Jaya Shakar Tumuluru; Shahab Sokhansanj; Christopher T. Wright; Richard D. Boardman

    2010-08-01

    Torrefaction is currently developing as an important preprocessing step to improve the quality of biomass in terms of physical properties, and proximate and ultimate composition. Torrefaction is a slow heating of biomass in an inert or reduced environment to a maximum temperature of 300 C. Torrefaction can also be defined as a group of products resulting from the partially controlled and isothermal pyrolysis of biomass occurring in a temperature range of 200-230 C and 270-280 C. Thus, the process can also be called a mild pyrolysis as it occurs at the lower temperature range of the pyrolysis process. At the end of the torrefaction process, a solid uniform product with lower moisture content and higher energy content than raw biomass is produced. Most of the smoke-producing compounds and other volatiles are removed during torrefaction, producing a final product that will have a lower mass but a higher heating value. An important aspect of research is to establish a degree of torrefaction where gains in heating value offset the loss of mass. There is a lack of literature on torrefaction reactor designs and a design sheet for estimating the dimensions of the torrefier based on capacity. This study includes (a) conducting a detailed review on the torrefaction of biomass in terms of understanding the process, product properties, off-gas compositions, and methods used, and (b) to design a moving bed torrefier, taking into account the basic fundamental heat and mass transfer calculations. Specific objectives include calculating the dimensions like diameter and height of the moving packed bed for different capacities, designing the heat loads and gas flow rates, and developing an interactive excel sheet where the user can define design specifications. In this report, 25-1000 kg/hr are used in equations for the design of the torrefier, examples of calculations, and specifications for the torrefier.

  11. Biomass Torrefaction Process Review and Moving Bed Torrefaction System Model Development

    SciTech Connect

    Jaya Shakar Tumuluru; Shahab Sokhansanj; Christopher T. Wright

    2010-08-01

    Torrefaction is currently developing as an important preprocessing step to improve the quality of biomass in terms of physical properties, and proximate and ultimate composition. Torrefaction is a slow heating of biomass in an inert or reduced environment to a maximum temperature of 300°C. Torrefaction can also be defined as a group of products resulting from the partially controlled and isothermal pyrolysis of biomass occurring in a temperature range of 200–230ºC and 270–280ºC. Thus, the process can also be called a mild pyrolysis as it occurs at the lower temperature range of the pyrolysis process. At the end of the torrefaction process, a solid uniform product with lower moisture content and higher energy content than raw biomass is produced. Most of the smoke-producing compounds and other volatiles are removed during torrefaction, producing a final product that will have a lower mass but a higher heating value. An important aspect of research is to establish a degree of torrefaction where gains in heating value offset the loss of mass. There is a lack of literature on torrefaction reactor designs and a design sheet for estimating the dimensions of the torrefier based on capacity. This study includes a) conducting a detailed review on the torrefaction of biomass in terms of understanding the process, product properties, off-gas compositions, and methods used, and b) to design a moving bed torrefier, taking into account the basic fundamental heat and mass transfer calculations. Specific objectives include calculating the dimensions like diameter and height of the moving packed bed for different capacities, designing the heat loads and gas flow rates, and developing an interactive excel sheet where the user can define design specifications. In this report, 25–1000 kg/hr are used in equations for the design of the torrefier, examples of calculations, and specifications for the torrefier.

  12. Numerical simulation of film coating process in a novel rotating fluidized bed.

    PubMed

    Nakamura, Hideya; Iwasaki, Tomohiro; Watano, Satoru

    2006-06-01

    In this study, numerical simulation of film coating process in a novel rotating fluidized bed (RFB) was conducted by using a Discrete Element Method (DEM)-Computational Fluid Dynamics (CFD) coupling model. Particle movements and fluid motions in a centrifugal force field were simulated at three-dimensional cylindrical coordinate, and this model was applied to film coating process. Film coating process in a RFB was numerically analyzed by using a simplified assumption that a particle was coated only when a particle existed within a spray zone. The experiments were also conducted and uniformity of sprayed material was evaluated by investigating color difference of the coated particles. As a result of the numerical simulation, three-dimensional bubble movements and particle circulation could be well simulated. In addition, mass of the sprayed material on a single particle in a RFB could be visualized by using our proposed model. The relationship between distribution of the sprayed material and the coating time was also analyzed. Calculated mass distributions of the sprayed material could be expressed by a normal distribution function, showing qualitative good agreement with the previous studies. Effect of the operating parameters, such as gas velocity and centrifugal acceleration, on the uniformity of the sprayed material was also investigated by both numerical and experimental approaches. Comparison of the coating process in a RFB with that in a conventional fluidized bed was also conducted by the numerical simulation. The result showed that uniformity of the sprayed material was greatly improved in a RFB due to the much smaller circulation time. PMID:16755055

  13. MODELING AND DESIGN FOR A DIRECT CARBON FUEL CELL WITH ENTRAINED FUEL AND OXIDIZER

    SciTech Connect

    Alan A. Kornhauser; Ritesh Agarwal

    2005-04-01

    The novel molten carbonate fuel cell design described in this report uses porous bed electrodes. Molten carbonate, with carbon fuel particles and oxidizer entrained, is circulated through the electrodes. Carbon may be reacted directly, without gasification, in a molten carbonate fuel cell. The cathode reaction is 2CO{sub 2} + O{sub 2} 4e{sup -} {yields} 2CO{sub 3}{sup =}, while the anode reaction can be either C + 2CO{sub 3}{sup =} {yields} 3CO{sub 2} + 4e{sup -} or 2C + CO{sub 3}{sup =} {yields} 3CO + 2e{sup -}. The direct carbon fuel cell has an advantage over fuel cells using coal-derived synthesis gas in that it provides better overall efficiency and reduces equipment requirements. Also, the liquid electrolyte provides a means for transporting the solid carbon. The porous bed cell makes use of this carbon transport ability of the molten salt electrolyte. A one-dimensional model has been developed for predicting the performance of this cell. For the cathode, dependent variables are superficial O{sub 2} and CO{sub 2} fluxes in the gas phase, superficial O{sub 2} and CO{sub 2} fluxes in the liquid phase, superficial current density through the electrolyte, and electrolyte potential. The variables are related by correlations, from the literature, for gas-liquid mass transfer, liquid-solid mass transfer, cathode current density, electrode overpotential, and resistivity of a liquid with entrained gas. For the anode, dependent variables are superficial CO{sub 2} flux in the gas phase, superficial CO{sub 2} flux in the liquid phase, superficial C flux, superficial current density through the electrolyte, and electrolyte potential. The same types of correlations relate the variables as in the cathode, with the addition of a correlation for resistivity of a fluidized bed. CO production is not considered, and axial dispersion is neglected. The model shows behavior typical of porous bed electrodes used in electrochemical processes. Efficiency is comparable to that of

  14. System for producing a uniform rubble bed for in situ processes

    DOEpatents

    Galloway, Terry R.

    1983-01-01

    A method and a cutter for producing a large cavity filled with a uniform bed of rubblized oil shale or other material, for in situ processing. A raise drill head (72) has a hollow body (76) with a generally circular base and sloping upper surface. A hollow shaft (74) extends from the hollow body (76). Cutter teeth (78) are mounted on the upper surface of the body (76) and relatively small holes (77) are formed in the body (76) between the cutter teeth (78). Relatively large peripheral flutes (80) around the body (76) allow material to drop below the drill head (72). A pilot hole is drilled into the oil shale deposit. The pilot hole is reamed into a large diameter hole by means of a large diameter raise drill head or cutter to produce a cavity filled with rubble. A flushing fluid, such as air, is circulated through the pilot hole during the reaming operation to remove fines through the raise drill, thereby removing sufficient material to create sufficient void space, and allowing the larger particles to fill the cavity and provide a uniform bed of rubblized oil shale.

  15. System for producing a uniform rubble bed for in situ processes

    DOEpatents

    Galloway, T.R.

    1983-07-05

    A method and a cutter are disclosed for producing a large cavity filled with a uniform bed of rubblized oil shale or other material, for in situ processing. A raise drill head has a hollow body with a generally circular base and sloping upper surface. A hollow shaft extends from the hollow body. Cutter teeth are mounted on the upper surface of the body and relatively small holes are formed in the body between the cutter teeth. Relatively large peripheral flutes around the body allow material to drop below the drill head. A pilot hole is drilled into the oil shale deposit. The pilot hole is reamed into a large diameter hole by means of a large diameter raise drill head or cutter to produce a cavity filled with rubble. A flushing fluid, such as air, is circulated through the pilot hole during the reaming operation to remove fines through the raise drill, thereby removing sufficient material to create sufficient void space, and allowing the larger particles to fill the cavity and provide a uniform bed of rubblized oil shale. 4 figs.

  16. Timescales of massive human entrainment.

    PubMed

    Fusaroli, Riccardo; Perlman, Marcus; Mislove, Alan; Paxton, Alexandra; Matlock, Teenie; Dale, Rick

    2015-01-01

    The past two decades have seen an upsurge of interest in the collective behaviors of complex systems composed of many agents entrained to each other and to external events. In this paper, we extend the concept of entrainment to the dynamics of human collective attention. We conducted a detailed investigation of the unfolding of human entrainment--as expressed by the content and patterns of hundreds of thousands of messages on Twitter--during the 2012 US presidential debates. By time-locking these data sources, we quantify the impact of the unfolding debate on human attention at three time scales. We show that collective social behavior covaries second-by-second to the interactional dynamics of the debates: A candidate speaking induces rapid increases in mentions of his name on social media and decreases in mentions of the other candidate. Moreover, interruptions by an interlocutor increase the attention received. We also highlight a distinct time scale for the impact of salient content during the debates: Across well-known remarks in each debate, mentions in social media start within 5-10 seconds after it occurs; peak at approximately one minute; and slowly decay in a consistent fashion across well-known events during the debates. Finally, we show that public attention after an initial burst slowly decays through the course of the debates. Thus we demonstrate that large-scale human entrainment may hold across a number of distinct scales, in an exquisitely time-locked fashion. The methods and results pave the way for careful study of the dynamics and mechanisms of large-scale human entrainment. PMID:25880357

  17. Timescales of massive human entrainment.

    PubMed

    Fusaroli, Riccardo; Perlman, Marcus; Mislove, Alan; Paxton, Alexandra; Matlock, Teenie; Dale, Rick

    2015-01-01

    The past two decades have seen an upsurge of interest in the collective behaviors of complex systems composed of many agents entrained to each other and to external events. In this paper, we extend the concept of entrainment to the dynamics of human collective attention. We conducted a detailed investigation of the unfolding of human entrainment--as expressed by the content and patterns of hundreds of thousands of messages on Twitter--during the 2012 US presidential debates. By time-locking these data sources, we quantify the impact of the unfolding debate on human attention at three time scales. We show that collective social behavior covaries second-by-second to the interactional dynamics of the debates: A candidate speaking induces rapid increases in mentions of his name on social media and decreases in mentions of the other candidate. Moreover, interruptions by an interlocutor increase the attention received. We also highlight a distinct time scale for the impact of salient content during the debates: Across well-known remarks in each debate, mentions in social media start within 5-10 seconds after it occurs; peak at approximately one minute; and slowly decay in a consistent fashion across well-known events during the debates. Finally, we show that public attention after an initial burst slowly decays through the course of the debates. Thus we demonstrate that large-scale human entrainment may hold across a number of distinct scales, in an exquisitely time-locked fashion. The methods and results pave the way for careful study of the dynamics and mechanisms of large-scale human entrainment.

  18. Preparative chromatography with supercritical fluids. Comparison of simulated moving bed and batch processes.

    PubMed

    Peper, Stephanie; Johannsen, Monika; Brunner, Gerd

    2007-12-28

    Preparative chromatography is a key technology for the separation of fine chemicals in production scale. Most of the published studies are carried out using liquid solvents as mobile phase. However, the used organic solvents can often be replaced by supercritical fluids. A reduction or renouncement of organic solvents does not only correspond to the trend of the so-called green chemistry--a sustainable, environmentally friendly production of chemical products. But a changeover to chromatography with supercritical fluids can also be reasonable under economic criteria. In this contribution a comparison between the Batch-supercritical fluid chromatography (Batch-SFC) process and the simulated moving bed (SMB)-SFC process is presented. Because of the minor importance of solvent consumption and solvent recovery in SFC, the separation systems were optimized primarily in terms of their specific productivity. For three of the four investigated model systems, the specific productivity of the SMB process is significantly higher than the productivity of the Batch process. Due to the fact, that the process with the higher specific productivity is not inevitably the more economical process, supplementary the costs of the process were considered. Therefore the comparison of the two processes was done from an economic point of view considering the minimum product price that has to be realized to fulfill the defined economic aim. It was found that although the optimized specific productivities of the SMB process were significantly higher than the productivities of the Batch process, the Batch process is the more profitable process for the investigated production rate range between 0.4 and 5t/a.

  19. Entrainment of coarse grains using a discrete particle model

    SciTech Connect

    Valyrakis, Manousos; Arnold, Roger B. Jr.

    2014-10-06

    Conventional bedload transport models and incipient motion theories relying on a time-averaged boundary shear stress are incapable of accounting for the effects of fluctuating near-bed velocity in turbulent flow and are therefore prone to significant errors. Impulse, the product of an instantaneous force magnitude and its duration, has been recently proposed as an appropriate criterion for quantifying the effects of flow turbulence in removing coarse grains from the bed surface. Here, a discrete particle model (DPM) is used to examine the effects of impulse, representing a single idealized turbulent event, on particle entrainment. The results are classified according to the degree of grain movement into the following categories: motion prior to entrainment, initial dislodgement, and energetic displacement. The results indicate that in all three cases the degree of particle motion depends on both the force magnitude and the duration of its application and suggest that the effects of turbulence must be adequately accounted for in order to develop a more accurate method of determining incipient motion. DPM is capable of simulating the dynamics of grain entrainment and is an appropriate tool for further study of the fundamental mechanisms of sediment transport.

  20. A new process control strategy for aqueous film coating of pellets in fluidised bed.

    PubMed

    Larsen, Crilles C; Sonnergaard, Jørn M; Bertelsen, Poul; Holm, Per

    2003-11-01

    The parameters with effect on maximum spray rate and maximum relative outlet air humidity when coating pellets in a fluidised bed were investigated. The tested variables include type of water based modified release film coating (Eudragit NE 30D, Eudragit RS 30D, Aquacoat ECD) coating principle (top spray, bottom spray), inlet air humidity and type of pellets (sugar spheres, microcrystalline cellulose pellets). The maximum spray rate was not influenced by the coating principles. The highest spray rate was obtained for the film polymer with the lowest tackiness which is assumed to be the controlling factor. The type of pellets affected the maximum spray rate. A thermodynamic model for the coating process is employed throughout the process and not just during steady state. The thermodynamic model is incorporated into a new process control strategy. The process control strategy is based on in-process calculation of degree of utilisation of the potential evaporation energy (DUE) of the outlet air and the relative outlet air humidity (RH). The spray rate is maximised using set points of DUE and RH as control parameters. The product temperature is controlled simultaneously by regulating the inlet air temperature. PMID:14592693

  1. A new process control strategy for aqueous film coating of pellets in fluidised bed.

    PubMed

    Larsen, Crilles C; Sonnergaard, Jørn M; Bertelsen, Poul; Holm, Per

    2003-11-01

    The parameters with effect on maximum spray rate and maximum relative outlet air humidity when coating pellets in a fluidised bed were investigated. The tested variables include type of water based modified release film coating (Eudragit NE 30D, Eudragit RS 30D, Aquacoat ECD) coating principle (top spray, bottom spray), inlet air humidity and type of pellets (sugar spheres, microcrystalline cellulose pellets). The maximum spray rate was not influenced by the coating principles. The highest spray rate was obtained for the film polymer with the lowest tackiness which is assumed to be the controlling factor. The type of pellets affected the maximum spray rate. A thermodynamic model for the coating process is employed throughout the process and not just during steady state. The thermodynamic model is incorporated into a new process control strategy. The process control strategy is based on in-process calculation of degree of utilisation of the potential evaporation energy (DUE) of the outlet air and the relative outlet air humidity (RH). The spray rate is maximised using set points of DUE and RH as control parameters. The product temperature is controlled simultaneously by regulating the inlet air temperature.

  2. Process for generating electricity in a pressurized fluidized-bed combustor system

    DOEpatents

    Kasper, Stanley

    1991-01-01

    A process and apparatus for generating electricity using a gas turbine as part of a pressurized fluidized-bed combustor system wherein coal is fed as a fuel in a slurry in which other constituents, including a sulfur sorbent such as limestone, are added. The coal is combusted with air in a pressurized combustion chamber wherein most of the residual sulfur in the coal is captured by the sulfur sorbent. After particulates are removed from the flue gas, the gas expands in a turbine, thereby generating electric power. The spent flue gas is cooled by heat exchange with system combustion air and/or system liquid streams, and the condensate is returned to the feed slurry.

  3. Scale-up research in a dual fluidized bed gasification process.

    PubMed

    Narobe, Miha; Golob, Janvit; Mele, Jernej; Sekavčnik, Mihael; Senegačnik, Andrej; Klinar, Dušan

    2015-01-01

    A successful co-gasification of plastics and biomass was achieved on the 100 kW dual fluidized bed (DFB) gasification pilot plant. The results of a pilot plant experiment were used as a sound basis for scale-up prediction to 750 kW semi-industrial DFB plant. By an eightfold increase of mass and heat flows a rather simplified co-gasification process was predicted. Namely, the losses occurring in gasification plants are expected to be relatively smaller in larger plants. The effect of decreased losses was studied with an equilibrium model. Three different situations were simulated with the following fixed values of losses: 70 kW, 115 kW and 160 kW. The model showed an increase in fuel conversion when losses were reduced.

  4. Scale-up research in a dual fluidized bed gasification process.

    PubMed

    Narobe, Miha; Golob, Janvit; Mele, Jernej; Sekavčnik, Mihael; Senegačnik, Andrej; Klinar, Dušan

    2015-01-01

    A successful co-gasification of plastics and biomass was achieved on the 100 kW dual fluidized bed (DFB) gasification pilot plant. The results of a pilot plant experiment were used as a sound basis for scale-up prediction to 750 kW semi-industrial DFB plant. By an eightfold increase of mass and heat flows a rather simplified co-gasification process was predicted. Namely, the losses occurring in gasification plants are expected to be relatively smaller in larger plants. The effect of decreased losses was studied with an equilibrium model. Three different situations were simulated with the following fixed values of losses: 70 kW, 115 kW and 160 kW. The model showed an increase in fuel conversion when losses were reduced. PMID:26085423

  5. Irregular Speech Rate Dissociates Auditory Cortical Entrainment, Evoked Responses, and Frontal Alpha

    PubMed Central

    Kayser, Stephanie J.; Ince, Robin A.A.; Gross, Joachim

    2015-01-01

    The entrainment of slow rhythmic auditory cortical activity to the temporal regularities in speech is considered to be a central mechanism underlying auditory perception. Previous work has shown that entrainment is reduced when the quality of the acoustic input is degraded, but has also linked rhythmic activity at similar time scales to the encoding of temporal expectations. To understand these bottom-up and top-down contributions to rhythmic entrainment, we manipulated the temporal predictive structure of speech by parametrically altering the distribution of pauses between syllables or words, thereby rendering the local speech rate irregular while preserving intelligibility and the envelope fluctuations of the acoustic signal. Recording EEG activity in human participants, we found that this manipulation did not alter neural processes reflecting the encoding of individual sound transients, such as evoked potentials. However, the manipulation significantly reduced the fidelity of auditory delta (but not theta) band entrainment to the speech envelope. It also reduced left frontal alpha power and this alpha reduction was predictive of the reduced delta entrainment across participants. Our results show that rhythmic auditory entrainment in delta and theta bands reflect functionally distinct processes. Furthermore, they reveal that delta entrainment is under top-down control and likely reflects prefrontal processes that are sensitive to acoustical regularities rather than the bottom-up encoding of acoustic features. SIGNIFICANCE STATEMENT The entrainment of rhythmic auditory cortical activity to the speech envelope is considered to be critical for hearing. Previous work has proposed divergent views in which entrainment reflects either early evoked responses related to sound encoding or high-level processes related to expectation or cognitive selection. Using a manipulation of speech rate, we dissociated auditory entrainment at different time scales. Specifically, our

  6. Doing Duo - a case study of entrainment in William Forsythe's choreography "Duo".

    PubMed

    Waterhouse, Elizabeth; Watts, Riley; Bläsing, Bettina E

    2014-01-01

    Entrainment theory focuses on processes in which interacting (i.e., coupled) rhythmic systems stabilize, producing synchronization in the ideal sense, and forms of phase related rhythmic coordination in complex cases. In human action, entrainment involves spatiotemporal and social aspects, characterizing the meaningful activities of music, dance, and communication. How can the phenomenon of human entrainment be meaningfully studied in complex situations such as dance? We present an in-progress case study of entrainment in William Forsythe's choreography Duo, a duet in which coordinated rhythmic activity is achieved without an external musical beat and without touch-based interaction. Using concepts of entrainment from different disciplines as well as insight from Duo performer Riley Watts, we question definitions of entrainment in the context of dance. The functions of chorusing, turn-taking, complementary action, cues, and alignments are discussed and linked to supporting annotated video material. While Duo challenges the definition of entrainment in dance as coordinated response to an external musical or rhythmic signal, it supports the definition of entrainment as coordinated interplay of motion and sound production by active agents (i.e., dancers) in the field. Agreeing that human entrainment should be studied on multiple levels, we suggest that entrainment between the dancers in Duo is elastic in time and propose how to test this hypothesis empirically. We do not claim that our proposed model of elasticity is applicable to all forms of human entrainment nor to all examples of entrainment in dance. Rather, we suggest studying higher order phase correction (the stabilizing tendency of entrainment) as a potential aspect to be incorporated into other models.

  7. Doing Duo - a case study of entrainment in William Forsythe's choreography "Duo".

    PubMed

    Waterhouse, Elizabeth; Watts, Riley; Bläsing, Bettina E

    2014-01-01

    Entrainment theory focuses on processes in which interacting (i.e., coupled) rhythmic systems stabilize, producing synchronization in the ideal sense, and forms of phase related rhythmic coordination in complex cases. In human action, entrainment involves spatiotemporal and social aspects, characterizing the meaningful activities of music, dance, and communication. How can the phenomenon of human entrainment be meaningfully studied in complex situations such as dance? We present an in-progress case study of entrainment in William Forsythe's choreography Duo, a duet in which coordinated rhythmic activity is achieved without an external musical beat and without touch-based interaction. Using concepts of entrainment from different disciplines as well as insight from Duo performer Riley Watts, we question definitions of entrainment in the context of dance. The functions of chorusing, turn-taking, complementary action, cues, and alignments are discussed and linked to supporting annotated video material. While Duo challenges the definition of entrainment in dance as coordinated response to an external musical or rhythmic signal, it supports the definition of entrainment as coordinated interplay of motion and sound production by active agents (i.e., dancers) in the field. Agreeing that human entrainment should be studied on multiple levels, we suggest that entrainment between the dancers in Duo is elastic in time and propose how to test this hypothesis empirically. We do not claim that our proposed model of elasticity is applicable to all forms of human entrainment nor to all examples of entrainment in dance. Rather, we suggest studying higher order phase correction (the stabilizing tendency of entrainment) as a potential aspect to be incorporated into other models. PMID:25374522

  8. Particle-Scale Controls on Entrainment and Deposition due to Debris Flows

    NASA Astrophysics Data System (ADS)

    Hill, K. M.; Maki, L.; Kaitna, R.

    2013-12-01

    When a debris flow - a large flow of boulders, gravels, sands, and mud - course down mountains, it can entrain materials many times the initial mass of the debris flow. The material is deposited at lower slopes. The amount of material they entrain and deposit can influence both the potential damage they do to habitat and communities in their paths and the landscape along the way. There is little quantitative understanding of the controls of entrainment and deposition along a debris flow path. We present experiments in a novel laboratory flume developed at the University of Minnesota to study particle-scale controls on entrainment and deposition due to debris flows. We control particle size distribution and water content in the flow itself and in an erodible bed over which the mixture flows, independently. Particle velocities, pore pressures, and local particle size distributions can be monitored, as can total erosion and deposition. Here, we first demonstrate how subtle differences in the bed structure or 'fabric' induced by the bed preparation can have dramatic differences on the entrainment rate of bed particles by the flowing mixture. Then we demonstrate the dependence of entrainment on particle size distribution in the flow and in the bed itself as it varies with angle of inclination of the bed. In all cases, we find that the erosion increases (or at lower angles, deposition decreases) with increasing angle of inclination of the bed. When the particles in the flow are uniform and the same size as those in the bed, we find the dependence of erosion on angle of inclination is linear. We find that single-sized systems exhibit more erosion and less deposition under the same conditions as their mixed counterparts. When the flow has a larger or smaller average particle size than that in the bed, the dependence of erosion on angle is somewhat more complicated. We model the variability by considering granular temperature in the flow, average stress on the bed, and the

  9. Particle-Scale Controls on Entrainment and Deposition due to Debris Flows

    NASA Astrophysics Data System (ADS)

    Hurst, M. D.; Mudd, S. M.; Walcott, R.; Attal, M.; Yoo, K.; Weinman, B. A.

    2011-12-01

    When a debris flow - a large flow of boulders, gravels, sands, and mud - course down mountains, it can entrain materials many times the initial mass of the debris flow. The material is deposited at lower slopes. The amount of material they entrain and deposit can influence both the potential damage they do to habitat and communities in their paths and the landscape along the way. There is little quantitative understanding of the controls of entrainment and deposition along a debris flow path. We present experiments in a novel laboratory flume developed at the University of Minnesota to study particle-scale controls on entrainment and deposition due to debris flows. We control particle size distribution and water content in the flow itself and in an erodible bed over which the mixture flows, independently. Particle velocities, pore pressures, and local particle size distributions can be monitored, as can total erosion and deposition. Here, we first demonstrate how subtle differences in the bed structure or 'fabric' induced by the bed preparation can have dramatic differences on the entrainment rate of bed particles by the flowing mixture. Then we demonstrate the dependence of entrainment on particle size distribution in the flow and in the bed itself as it varies with angle of inclination of the bed. In all cases, we find that the erosion increases (or at lower angles, deposition decreases) with increasing angle of inclination of the bed. When the particles in the flow are uniform and the same size as those in the bed, we find the dependence of erosion on angle of inclination is linear. We find that single-sized systems exhibit more erosion and less deposition under the same conditions as their mixed counterparts. When the flow has a larger or smaller average particle size than that in the bed, the dependence of erosion on angle is somewhat more complicated. We model the variability by considering granular temperature in the flow, average stress on the bed, and the

  10. Simulating entrainment and particle fluxes in stratified estuaries

    SciTech Connect

    Jensen, A.; Jirka, G.; Lion, L.W.; Brunk, B.

    1999-04-01

    Settling and entrainment are the dominant processes governing noncohesive particle concentration throughout the water column of salt-wedge estuaries. Determination of the relative contribution of these transport processes is complicated by vertical gradients in turbulence and fluid density. A differential-turbulence column (DTC) was designed to simulate a vertical section of a natural water column. With satisfactory characterization of turbulence dissipation and saltwater entrainment, the DTC facilitates controlled studies of suspended particles under estuarine conditions. The vertical decay of turbulence in the DTC was found to obey standard scaling law relations when the characteristic length scale for turbulence in the apparatus was incorporated. The entrainment rate of a density interface also followed established grid-stirred turbulence scaling laws. These relations were used to model the change in concentration of noncohesive particles above a density interface. Model simulations and experimental data from the DTC were consistent over the range of conditions encountered in natural salt-wedge estuaries. Results suggest that when the ratio of entrainment rate to particle settling velocity is small, sedimentation is the dominant transport process, while entrainment becomes significant as the ratio increases.

  11. Acoustic bed velocity and bed load dynamics in a large sand bed river

    USGS Publications Warehouse

    Gaeuman, D.; Jacobson, R.B.

    2006-01-01

    Development of a practical technology for rapid quantification of bed load transport in large rivers would represent a revolutionary advance for sediment monitoring and the investigation of fluvial dynamics. Measurement of bed load motion with acoustic Doppler current profiles (ADCPs) has emerged as a promising approach for evaluating bed load transport. However, a better understanding of how ADCP data relate to conditions near the stream bed is necessary to make the method practical for quantitative applications. In this paper, we discuss the response of ADCP bed velocity measurements, defined as the near-bed sediment velocity detected by the instrument's bottom-tracking feature, to changing sediment-transporting conditions in the lower Missouri River. Bed velocity represents a weighted average of backscatter from moving bed load particles and spectral reflections from the immobile bed. The ratio of bed velocity to mean bed load particle velocity depends on the concentration of the particles moving in the bed load layer, the bed load layer thickness, and the backscatter strength from a unit area of moving particles relative to the echo strength from a unit area of unobstructed bed. A model based on existing bed load transport theory predicted measured bed velocities from hydraulic and grain size measurements with reasonable success. Bed velocities become more variable and increase more rapidly with shear stress when the transport stage, defined as the ratio of skin friction to the critical shear stress for particle entrainment, exceeds a threshold of about 17. This transition in bed velocity response appears to be associated with the appearance of longer, flatter bed forms at high transport stages.

  12. Timescales of Massive Human Entrainment

    PubMed Central

    Fusaroli, Riccardo; Perlman, Marcus; Mislove, Alan; Paxton, Alexandra; Matlock, Teenie; Dale, Rick

    2015-01-01

    The past two decades have seen an upsurge of interest in the collective behaviors of complex systems composed of many agents entrained to each other and to external events. In this paper, we extend the concept of entrainment to the dynamics of human collective attention. We conducted a detailed investigation of the unfolding of human entrainment—as expressed by the content and patterns of hundreds of thousands of messages on Twitter—during the 2012 US presidential debates. By time-locking these data sources, we quantify the impact of the unfolding debate on human attention at three time scales. We show that collective social behavior covaries second-by-second to the interactional dynamics of the debates: A candidate speaking induces rapid increases in mentions of his name on social media and decreases in mentions of the other candidate. Moreover, interruptions by an interlocutor increase the attention received. We also highlight a distinct time scale for the impact of salient content during the debates: Across well-known remarks in each debate, mentions in social media start within 5–10 seconds after it occurs; peak at approximately one minute; and slowly decay in a consistent fashion across well-known events during the debates. Finally, we show that public attention after an initial burst slowly decays through the course of the debates. Thus we demonstrate that large-scale human entrainment may hold across a number of distinct scales, in an exquisitely time-locked fashion. The methods and results pave the way for careful study of the dynamics and mechanisms of large-scale human entrainment. PMID:25880357

  13. Evaluation of Selected Chemical Processes for Production of Low-cost Silicon, Phase 3. [using a fluidized bed reactor

    NASA Technical Reports Server (NTRS)

    Blocher, J. M., Jr.; Browning, M. F.

    1979-01-01

    The construction and operation of an experimental process system development unit (EPSDU) for the production of granular semiconductor grade silicon by the zinc vapor reduction of silicon tetrachloride in a fluidized bed of seed particles is presented. The construction of the process development unit (PDU) is reported. The PDU consists of four critical units of the EPSDU: the fluidized bed reactor, the reactor by product condenser, the zinc vaporizer, and the electrolytic cell. An experimental wetted wall condenser and its operation are described. Procedures are established for safe handling of SiCl4 leaks and spills from the EPSDU and PDU.

  14. Pyrolucite fluidized-bed reactor (PFBR): a robust and compact process for removing manganese from groundwater.

    PubMed

    Dashtban Kenari, Seyedeh Laleh; Barbeau, Benoit

    2014-02-01

    The purpose of this paper is to introduce a pyrolucite fluidized-bed reactor (PFBR) as a potential drinking water process to treat groundwater containing high levels of dissolved manganese (Mn(II)) (0.5-3 mg/L) and reduce its concentration to <0.02 mg/L in treated water. A pilot-scale study was conducted under dynamic conditions using synthetic groundwater (SGW), to elucidate the effect of operational conditions and groundwater composition on manganese (Mn) removal achieved by the PFBR. Results demonstrated almost complete Mn removal (close to 100%) in less than 1 min under all tested operational conditions (influent Mn concentration of 0.5-3 mg/L, calcium (Ca(2+)) hardness of 0-200 mg CaCO3/L, pH of 6.2-7.8, temperature of 9 & 23 °C and high hydraulic loading rate (HLR) of 24-63 m/h (i.e., bed expansion of 0-30%)). Improved Mn removal profile was achieved at higher water temperature. Also, the results showed that adsorption of Mn(II) onto pyrolucite and subsequent slower surface oxidation of sorbed Mn(II) was the only mechanism responsible for Mn removal while direct oxidation of Mn(II) by free chlorine did not occur even at high concentrations of Mn(II) and free chlorine and elevated temperatures. Higher average mass transfer coefficient and consequently adsorption rate was achieved at elevated HLR. Increasing effluent free chlorine residuals from 1.0 to 2.0-2.6 mg Cl2/L allowed increasing the operation time needed for media regeneration from 6 days to >12 days. Turbidity was maintained around 0.2 NTU during the entire test periods indicating good capture of MnOx colloids within the PFBR. PMID:24183400

  15. Nitrogen cycling processes and microbial community composition in bed sediments in the Yukon River at Pilot Station

    USGS Publications Warehouse

    Repert, Deborah A.; Underwood, Jennifer C.; Smith, Richard L.; Song, Bongkeun

    2014-01-01

    Information on the contribution of nitrogen (N)-cycling processes in bed sediments to river nutrient fluxes in large northern latitude river systems is limited. This study examined the relationship between N-cycling processes in bed sediments and N speciation and loading in the Yukon River near its mouth at the Bering Sea. We conducted laboratory bioassays to measure N-cycling processes in sediment samples collected over distinct water cycle seasons. In conjunction, the microbial community composition in the bed sediments using genes involved in N-cycling (narG, napA, nosZ, and amoA) and 16S rRNA gene pyrosequences was examined. Temporal variation was observed in net N mineralization, nitrate uptake, and denitrification rate potentials and correlated strongly with sediment carbon (C) and extractable N content and microbial community composition rather than with river water nutrient concentrations. The C content of the bed sediment was notably impacted by the spring flood, ranging from 1.1% in the midst of an ice-jam to 0.1% immediately after ice-out, suggesting a buildup of organic material (OM) prior to scouring of the bed sediments during ice break up. The dominant members of the microbial community that explained differences in N-processing rates belonged to the genera Crenothrix,Flavobacterium, and the family of Comamonadaceae. Our results suggest that biogeochemical processing rates in the bed sediments appear to be more coupled to hydrology, nutrient availability in the sediments, and microbial community composition rather than river nutrient concentrations at Pilot Station.

  16. Nitrogen cycling processes and microbial community composition in bed sediments in the Yukon River at Pilot Station

    NASA Astrophysics Data System (ADS)

    Repert, Deborah A.; Underwood, Jennifer C.; Smith, Richard L.; Song, Bongkeun

    2014-12-01

    Information on the contribution of nitrogen (N)-cycling processes in bed sediments to river nutrient fluxes in large northern latitude river systems is limited. This study examined the relationship between N-cycling processes in bed sediments and N speciation and loading in the Yukon River near its mouth at the Bering Sea. We conducted laboratory bioassays to measure N-cycling processes in sediment samples collected over distinct water cycle seasons. In conjunction, the microbial community composition in the bed sediments using genes involved in N-cycling (narG, napA, nosZ, and amoA) and 16S rRNA gene pyrosequences was examined. Temporal variation was observed in net N mineralization, nitrate uptake, and denitrification rate potentials and correlated strongly with sediment carbon (C) and extractable N content and microbial community composition rather than with river water nutrient concentrations. The C content of the bed sediment was notably impacted by the spring flood, ranging from 1.1% in the midst of an ice-jam to 0.1% immediately after ice-out, suggesting a buildup of organic material (OM) prior to scouring of the bed sediments during ice break up. The dominant members of the microbial community that explained differences in N-processing rates belonged to the genera Crenothrix, Flavobacterium, and the family of Comamonadaceae. Our results suggest that biogeochemical processing rates in the bed sediments appear to be more coupled to hydrology, nutrient availability in the sediments, and microbial community composition rather than river nutrient concentrations at Pilot Station.

  17. Initial operating capability for the hypercluster parallel-processing test bed

    NASA Technical Reports Server (NTRS)

    Cole, Gary L.; Blech, Richard A.; Quealy, Angela

    1989-01-01

    The NASA Lewis Research Center is investigating the benefits of parallel processing to applications in computational fluid and structural mechanics. To aid this investigation, NASA Lewis is developing the Hypercluster, a multi-architecture, parallel-processing test bed. The initial operating capability (IOC) being developed for the Hypercluster is described. The IOC will provide a user with a programming/operating environment that is interactive, responsive, and easy to use. The IOC effort includes the development of the Hypercluster Operating System (HYCLOPS). HYCLOPS runs in conjunction with a vendor-supplied disk operating system on a Front-End Processor (FEP) to provide interactive, run-time operations such as program loading, execution, memory editing, and data retrieval. Run-time libraries, that augment the FEP FORTRAN libraries, are being developed to support parallel and vector processing on the Hypercluster. Special utilities are being provided to enable passage of information about application programs and their mapping to the operating system. Communications between the FEP and the Hypercluster are being handled by dedicated processors, each running a Message-Passing Kernel, (MPK). A shared-memory interface allows rapid data exchange between HYCLOPS and the communications processors. Input/output handlers are built into the HYCLOPS-MPK interface, eliminating the need for the user to supply separate I/O support programs on the FEP.

  18. Combined production and purification of hydrogen from methanol using steam iron process in fixed bed reactor

    NASA Astrophysics Data System (ADS)

    Campo, R.; Durán, P.; Plou, J.; Herguido, J.; Peña, J. A.

    2013-11-01

    A research work is being conducted to study the combined production and purification of hydrogen by means of redox processes departing from biomass fast pyrolysis oils (bio-oils). To achieve that goal, methanol has been used as featured material because it is the most representative compound of the alcoholic fraction of bio-oils. The study has been carried out in a fixed bed reactor where methanol decomposes in H2 and CO when gets in contact with a reactive solid based in an iron oxide at temperatures above 600 °C. During the first stage of the “steam-iron” process, reactive gases reduce the iron oxide to metallic iron. Afterward, in a following step, the previously reduced iron is reoxidized by steam producing a high purity hydrogen stream. Although coke deposition does exist during the reducing stage, this behaves as inert during the reoxidation process. Coke inert role has been corroborated by GC, SEM and TEM techniques, showing that carbon deposits were constituted by ordered structures (carbon nanotubes). The determination of the hydrogen production along successive cycles allowed the evaluation of the effect of temperature and alternating reactive atmospheres on the stability of the solid, as well as the optimum conditions for such purpose.

  19. Saturation point representation of cloud-top entrainment instability

    NASA Technical Reports Server (NTRS)

    Boers, Reinout

    1991-01-01

    Cloud-top entrainment instability was investigated using a mixing line analysis. Mixing time scales are closely related to the actual size of the parcel, so that local instabilities are largely dependent on the scales of mixing near the cloud top. Given a fixed transport velocity, variation over a small range of parcel length scales (parcel mixing velocities) turns an energy-producing mixing process into an energy-consuming mixing process. It is suggested that a single criterion for cloud-top entrainment instability will not be found due to the role of at least three factors operating more or less independently; the stability of the mixing line, the entrainment speed, and the strength of the internal boundary-layer circulation.

  20. Electrification of particulate entrained fluid flows-Mechanisms, applications, and numerical methodology

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Gu, Zhaolin

    2015-10-01

    Particulates in natural and industrial flows have two basic forms: liquid (droplet) and solid (particle). Droplets would be charged in the presence of the applied electric field (e.g. electrospray). Similar to the droplet charging, particles can also be charged under the external electric field (e.g. electrostatic precipitator), while in the absence of external electric field, tribo-electrostatic charging is almost unavoidable in gas-solid two-phase flows due to the consecutive particle contacts (e.g. electrostatic in fluidized bed or wind-blown sand). The particle charging may be beneficial, or detrimental. Although electrostatics in particulate entrained fluid flow systems have been so widely used and concerned, the mechanisms of particulate charging are still lack of a thorough understanding. The motivation of this review is to explore a clear understanding of particulate charging and movement of charged particulate in two-phase flows, by summarizing the electrification mechanisms, physical models of particulate charging, and methods of charging/charged particulate entrained fluid flow simulations. Two effective methods can make droplets charged in industrial applications: corona charging and induction charging. The droplet charge to mass ratio by corona charging is more than induction discharge. The particle charging through collisions could be attributed to electron transfer, ion transfer, material transfer, and/or aqueous ion shift on particle surfaces. The charges on charged particulate surface can be measured, nevertheless, the charging process in nature or industry is difficult to monitor. The simulation method might build a bridge of investigating from the charging process to finally charged state on particulate surface in particulate entrained fluid flows. The methodology combining the interface tracking under the action of the applied electric with the fluid flow governing equations is applicable to the study of electrohydrodynamics problems. The charge

  1. Incompressible SPH scour model for movable bed dam break flows

    NASA Astrophysics Data System (ADS)

    Ran, Qihua; Tong, Jian; Shao, Songdong; Fu, Xudong; Xu, Yueping

    2015-08-01

    In this study an incompressible smoothed particle hydrodynamics (ISPH) approach coupled with the sediment erosion model is developed to investigate the sediment bed scour and grain movement under the dam break flows. Two-phase formulations are used in the ISPH numerical algorithms to examine the free surface and bed evolution profiles, in which the entrained sediments are treated as a different fluid component as compared with the water. The sediment bed erosion model is based on the concept of pick-up flow velocity and the sediment is initiated when the local flow velocity exceeds a critical value. The proposed model is used to reproduce the sediment erosion and follow-on entrainment process under an instantaneous dam break flow and the results are compared with those from the weakly compressible moving particle semi-implicit (WCMPS) method as well as the experimental data. It has been demonstrated that the two-phase ISPH model performed well with the experimental data. The study shows that the ISPH modelling approach can accurately predict the dynamic sediment scouring process without the need to use empirical sediment transport formulas.

  2. Flow Transformation in Pyroclastic Density Currents: Entrainment and Granular Dynamics during the 2006 eruption of Tungurahua

    NASA Astrophysics Data System (ADS)

    Dufek, J.; Benage, M. C.; Geist, D.; Harpp, K. S.

    2013-12-01

    have conducted high resolution simulations in concert with detailed measurements of these flows from both up flow and down flow from the transformation to document the process of dense to dilute flow transition. The field characterization includes mapping of the flows, grain size analysis, documenting flow direction indicators, comminution rounding, thermal proxies for air entrainment, and bed form documentation. We used a three-dimensional, multiphase (Eulerian-Eulerian-Lagrangian, EEL) modeling approach to describe size sorting, concentration gradients, and stresses in these evolving flows using the topography of the near Chambo River crossing (Dufek and Bergantz, 2007a; Dufek and Bertgantz, 2007b). The numerical models reveal extensive entrainment in the surge-generating phase of the flow, and secondary plume generation as fine ash in transported by hot gases higher into the atmosphere. Granular waves develop in the confined channels of the dense flow resulting bed shear stress perturbations. These granular instabilities and entrainment result in pulsing conditions in the surge, accounting for much of the unsteady behavior that results in fluctuations in grain size and bed form in the surge deposits.

  3. Process Development of Adenoviral Vector Production in Fixed Bed Bioreactor: From Bench to Commercial Scale.

    PubMed

    Lesch, Hanna P; Heikkilä, Kati M; Lipponen, Eevi M; Valonen, Piia; Müller, Achim; Räsänen, Eva; Tuunanen, Tarja; Hassinen, Minna M; Parker, Nigel; Karhinen, Minna; Shaw, Robert; Ylä-Herttuala, Seppo

    2015-08-01

    Large-scale vector manufacturing for phase III and beyond has proven to be challenging. Upscaling the process with suspension cells is increasingly feasible, but many viral production applications are still applicable only in adherent settings. Scaling up the adherent system has proven to be troublesome. The iCELLis(®) disposable fixed-bed bioreactors offer a possible option for viral vector manufacturing in large quantities in an adherent environment. In this study, we have optimized adenovirus serotype 5 manufacturing using iCELLis Nano with a cultivation area up to 4 m(2). HEK293 cell cultivation, infection, and harvest of the virus (by lysing the cells inside the bioreactor) proved possible, reaching total yield of up to 1.6×10(14) viral particles (vp)/batch. The iCELLis 500 is designed to satisfy demand for large-scale requirements. Inoculating a large quantity of cell mass into the iCELLis 500 was achieved by first expanding the cell mass in suspension. Upscaling the process into an iCELLis 500/100 m(2) cultivation area cassette was practical and produced up to 6.1×10(15) vp. Flask productivity per cm(2) in iCELLis Nano and iCELLis 500 was in the same range. As a conclusion, we showed for the first time that iCELLis 500 equipment has provided an effective way to manufacture large batches of adenoviral vectors. PMID:26176404

  4. Investigation of non-intrusive radiometers for entrained gasifier temperature measurement. Fourth quarterly report, August 1-October 31, 1984. Revision 3

    SciTech Connect

    Gat, N.

    1985-03-11

    The objective of this project is to develop and test a nonintrusive radiometer for entrained bed gasifier/combustor temperature measurements. This quarterly report is focused on design, fabrication and testing of radiometers. 3 refs., 5 figs., 1 tab.

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

    SciTech Connect

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

    2014-01-15

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

  6. Observations of near-bed sediment convergence processes at Diamond Shoals, NC

    NASA Astrophysics Data System (ADS)

    Warner, J. C.; List, J. H.; Voulgaris, G.; Sanchez, A.

    2010-12-01

    Diamond Shoals is a large sedimentary deposit approximately 20 km in length that spans the shelf width from Cape Hatteras, NC to the shelf break. This shoal is part of a series of convergent features associated with the cuspate forelands of the Carolinas coast. The processes that have formed and maintain these shoals are not well understood, however, previous studies have suggested wind, wave, and tidal processes have maintaned these configurations. In this study we present field measurments of waves, bottom orbital velocities, near-bottom mean currents, and near-bed suspended-sediment concentration data from calibrated Acoustic Backscatter Sensors (ABSs) at two different sites on the north and south sides of the shoal. A rotating sonar was also placed at the North Site to measure sea floor bed forms. The instruments were deployed in approoximately 12 m of water from January through April of 2009. The time period is marked with several storms events that last on the order of a few days and reoccurred approximately every 5 days. Results demonstrate a strong correlation between the wind forcing (that reached up to 20 m/s) with the surface waves (up to 4m) demonstrating local generation. Bottom orbital velocities from surface waves exceeded threshold for sediment mobility during storms and correlate with increased sediment concentrations in the water column. Near-bottom currents also generate increased bottom stress capable of locally suspending sediment. Suspended-sediment concentrations reached up to 100 mg/l during high energy events. In addition, sonar images show re-orientation of the sea floor ripples during storm events. Advective sediment fluxes computed from the ABS and near-bottom mean currents show a net transport eastward at the south site and southward at the northern site. These fluxes indicate converging and offshore orientated net sediment transport, providing a mechanism to maintain the shoal. Observations are compared to atmospheric forcings

  7. Multiple sensor detection of process phenomena in laser powder bed fusion

    NASA Astrophysics Data System (ADS)

    Lane, Brandon; Whitenton, Eric; Moylan, Shawn

    2016-05-01

    Laser powder bed fusion (LPBF) is an additive manufacturing (AM) process in which a high power laser melts metal powder layers into complex, three-dimensional shapes. LPBF parts are known to exhibit relatively high residual stresses, anisotropic microstructure, and a variety of defects. To mitigate these issues, in-situ measurements of the melt-pool phenomena may illustrate relationships between part quality and process signatures. However, phenomena such as spatter, plume formation, laser modulation, and melt-pool oscillations may require data acquisition rates exceeding 10 kHz. This hinders use of relatively data-intensive, streaming imaging sensors in a real-time monitoring and feedback control system. Single-point sensors such as photodiodes provide the temporal bandwidth to capture process signatures, while providing little spatial information. This paper presents results from experiments conducted on a commercial LPBF machine which incorporated synchronized, in-situ acquisition of a thermal camera, high-speed visible camera, photodiode, and laser modulation signal during fabrication of a nickel alloy 625 AM part with an overhang geometry. Data from the thermal camera provides temperature information, the visible camera provides observation of spatter, and the photodiode signal provides high temporal bandwidth relative brightness stemming from the melt pool region. In addition, joint-time frequency analysis (JTFA) was performed on the photodiode signal. JTFA results indicate what digital filtering and signal processing are required to highlight particular signatures. Image fusion of the synchronized data obtained over multiple build layers allows visual comparison between the photodiode signal and relating phenomena observed in the imaging detectors.

  8. [The development of the multifunctional automatic rotating bed with process-monitoring].

    PubMed

    Geng, Hongzhu; Hu, Monong; Cheng, Ping; Dong, Kejiang; Zhang, Jiaxia; Sun, Juefei

    2013-04-01

    We have developed a new rotating bed for the old and the paralised people. This rotating bed is composed of two bed heads at front and at end, bed boards, guardrails, an electric motor, a reducer, an induction locator and a set of electronic controls. With the preestablished program, the angle between the left/right bed board and the middle board is changed by rotating the left/right board around the rotation axis, and the gravity direction between the human body and the ground is changed by the rotation of the middle board as a whole, so that the middle bed board and the left and right ones will act respectively as supporters of weight of the person who is lying on his back or on his side. In this way, a person can turn over automatically, comfortably and naturally when he/she is asleep. This rotating bed meets the physiological needs of a sleeping person, and people with turning over problems can turn over in a comfortable and natural way by means of biotechnology. It can also improve the quality of sleep and help avoid decubitus. In addition, it can be used to promote the rehabilitation of those who are paralysed by reason of its passive exercising function.

  9. Observing of entrainment using small UAS

    NASA Astrophysics Data System (ADS)

    Martin, S.; Bange, J.; Beyrich, F.

    2012-04-01

    Entrainment processes between the atmospheric boundary layer and the free atmosphere are important concerning vertical exchange of momentum, energy, water vapor, trace gases and aerosol. The transition zone between the convectively mixed boundary layer and the stably stratified free atmosphere is called the entrainment zone (EZ). The EZ restrains the domain of turbulence by a temperature inversion and acts as a lid to pollutants. Measurement flights of the mini meteorological aerial vehicle (M2AV) of the Technische Universität Braunschweig were performed in spring 2011 to determine the capability of the unmanned aerial system (UAS) to measure the structure of the EZ. The campaign took place at the Meteorological Observatory Lindenberg / Richard-Aßmann-Observatory of the German Meteorological Service, which is located close to Berlin. Besides the M2AV flights, standard observations were performed by a 12 m and 99 m tower, a sodar, ceilometer and radiosondes. A tethered balloon with measurement units at six different levels was operated especially for this campaign. The measurements of these systems were used to determine the inversion layer and to capture its diurnal cycle. The talk will be focused on vertical profiles of the M2AV up to the free atmosphere, detailed analysis of spatial series of w'θ' at different altitudes and on vertical profiles of normalized variances of the vertical wind component and the potential temperature.

  10. On robustness of phase resetting to cell division under entrainment.

    PubMed

    Ahmed, Hafiz; Ushirobira, Rosane; Efimov, Denis

    2015-12-21

    The problem of phase synchronization for a population of genetic oscillators (circadian clocks, synthetic oscillators, etc.) is considered in this paper, taking into account a cell division process and a common entrainment input in the population. The proposed analysis approach is based on the Phase Response Curve (PRC) model of an oscillator (the first order reduced model obtained for the linearized system and inputs with infinitesimal amplitude). The occurrence of cell division introduces state resetting in the model, placing it in the class of hybrid systems. It is shown that without common entraining input in all oscillators, the cell division acts as a disturbance causing phase drift, while the presence of entrainment guarantees boundedness of synchronization phase errors in the population. The performance of the obtained solutions is demonstrated via computer experiments for two different models of circadian/genetic oscillators (Neurospora׳s circadian oscillation model and the repressilator).

  11. On robustness of phase resetting to cell division under entrainment.

    PubMed

    Ahmed, Hafiz; Ushirobira, Rosane; Efimov, Denis

    2015-12-21

    The problem of phase synchronization for a population of genetic oscillators (circadian clocks, synthetic oscillators, etc.) is considered in this paper, taking into account a cell division process and a common entrainment input in the population. The proposed analysis approach is based on the Phase Response Curve (PRC) model of an oscillator (the first order reduced model obtained for the linearized system and inputs with infinitesimal amplitude). The occurrence of cell division introduces state resetting in the model, placing it in the class of hybrid systems. It is shown that without common entraining input in all oscillators, the cell division acts as a disturbance causing phase drift, while the presence of entrainment guarantees boundedness of synchronization phase errors in the population. The performance of the obtained solutions is demonstrated via computer experiments for two different models of circadian/genetic oscillators (Neurospora׳s circadian oscillation model and the repressilator). PMID:26463679

  12. Fluidized-bed catalytic coal-gasification process. [US patent; pretreatment to minimize agglomeration

    DOEpatents

    Euker, C.A. Jr.; Wesselhoft, R.D.; Dunkleman, J.J.; Aquino, D.C.; Gouker, T.R.

    1981-09-14

    Coal or similar carbonaceous solids impregnated with gasification catalyst constituents are oxidized by contact with a gas containing between 2 vol % and 21 vol % oxygen at a temperature between 50 and 250/sup 0/C in an oxidation zone and the resultant oxidized, catalyst impregnated solids are then gasified in a fluidized bed gasification zone at an elevated pressure. The oxidation of the catalyst impregnated solids under these conditions insures that the bed density in the fluidized bed gasification zone will be relatively high even though the solids are gasified at elevated pressure and temperature.

  13. Packaged fluidized bed boiler incorporates steam calorimeter to maintain steam quality. [Central Soya processing plant in Marian, Ohio

    SciTech Connect

    Toy, D.A.

    1984-04-01

    Engineers at the Central Soya processing plant in Marion, Ohio were faced with the problem of upgrading or replacing two 20 y old coal-fired steam boilers. A boiler design was chosen which could fire all types of coal, oil, and natural gas - either individually or simultaneously. Boiler efficiency and environmental quality were enhanced by several design features. By incorporating a throttling steam calorimeter into the boiler design, accurate measurements of the moisture of the motive steam produced were facilitated. To achieve high combustion efficiency, a concave fluidized bed was used to control the circulation of solids within the bed. In addition to environmental compliance, the fluidized bed boiler has saved 1000 tons of coal over a 2 y period at a production capacity of 4000 lb steam/h. System efficiency has increased from 75% to 85%. The conversion has provided both environmental and economic justification, while providing more reliable service with minimal operating and operating costs.

  14. Crustal entrainment and pulsar glitches.

    PubMed

    Chamel, N

    2013-01-01

    Large pulsar frequency glitches are generally interpreted as sudden transfers of angular momentum between the neutron superfluid permeating the inner crust and the rest of the star. Despite the absence of viscous drag, the neutron superfluid is strongly coupled to the crust due to nondissipative entrainment effects. These effects are shown to severely limit the maximum amount of angular momentum that can possibly be transferred during glitches. In particular, it is found that the glitches observed in the Vela pulsar require an additional reservoir of angular momentum.

  15. Crustal entrainment and pulsar glitches.

    PubMed

    Chamel, N

    2013-01-01

    Large pulsar frequency glitches are generally interpreted as sudden transfers of angular momentum between the neutron superfluid permeating the inner crust and the rest of the star. Despite the absence of viscous drag, the neutron superfluid is strongly coupled to the crust due to nondissipative entrainment effects. These effects are shown to severely limit the maximum amount of angular momentum that can possibly be transferred during glitches. In particular, it is found that the glitches observed in the Vela pulsar require an additional reservoir of angular momentum. PMID:23383772

  16. A process-based model for erosion of Macoma balthica-affected mud beds

    NASA Astrophysics Data System (ADS)

    van Prooijen, Bram C.; Montserrat, Francesc; Herman, Peter M. J.

    2011-04-01

    Modeling the effect of biota on sediment dynamics is a difficult task. In this paper we re-analyze experimental results of Willows et al. (1998) on the effects of Macoma balthica on sediment erosion. A process-based framework is proposed, fully compatible with a physical description of erosion processes in case of no biogenic influences. The bed is represented by a fluff layer on top of a substrate. A characteristic feature of the framework is that the sediment is represented by a probability density distribution for the critical shear stress, allowing for Type I and Type II erosion. M. balthica increases the sediment mass in the fluff layer. This increase is determined by considering the action radius, the overlap of feeding areas, and the feeding rate per animal. The calibrated action radius and feeding rate were in the range as found in the literature. The distribution of sediment over the erodibility classes and the erosion rate parameter are hardly influenced at all. Due to overlapping feeding areas, the effect is non-linear with density of the animals. The model results are in close agreement with the measured results, suggesting that no further formulations of biological effects are needed to simulate the experiments of Willows et al. (1998). In nature, other effects like disrupting the biofilm by grazing can be of importance and should be included in a later stage. This study emphasizes the crucial role of sediment availability and the effect of biota on it. This aspect needs more attention in future experiments. The proposed model turned out to work well for the effects of M. balthica and offers opportunities to include other biogenic effects in a process-based way as well.

  17. Reverse osmosis concentrate treatment by chemical oxidation and moving bed biofilm processes.

    PubMed

    Vendramel, S M R; Justo, A; González, O; Sans, C; Esplugas, S

    2013-01-01

    In the present work, four oxidation techniques were investigated (O3, O3/UV, H2O2/O3, O3/H2O2/UV) to pre-treat reverse osmosis (RO) concentrate before treatment in a moving-bed biofilm reactor (MBBR) system. Without previous oxidation, the MBBR was able to remove a small fraction of the chemical oxygen demand (COD) (5-20%) and dissolved organic carbon (DOC) (2-15%). When the concentrate was previously submitted to oxidation, DOC removal efficiencies in the MBBR increased to 40-55%. All the tested oxidation techniques improved concentrate biodegradability. The concentrate treated by the combined process (oxidation and MBBR) presented residual DOC and COD in the ranges of 6-12 and 25-41 mg L(-1), respectively. Nitrification of the RO concentrate, pre-treated by oxidation, was observed in the MBBR. Ammonium removal was comprised between 54 and 79%. The results indicate that the MBBR was effective for the treatment of the RO concentrate, previously submitted to oxidation, generating water with an improved quality. PMID:24334891

  18. Mechanisms of flow through compressible porous beds in sedimentation, filtration, centrifugation, deliquoring, and ceramic processing

    SciTech Connect

    Tiller, F.M.

    1992-06-01

    The University of Houston research program is aimed at the specific area of solid/liquid separation including sedimentation, thickening, cake filtration, centrifugation, expression, washing, deep-bed filtration, screening, and membrane separation. Unification of the theoretical approaches to the various solid/liquid separation operations is the principle objective of the research. Exploring new aspects of basic separation mechanisms, verification of theory with experiment, development of laboratory procedures for obtaining data for design, optimizing operational methods, and transferring the results to industry are a part of the Houston program. New methodology developed in our program now permits an engineer or scientist to handle thickening, cake filtration, centrigual filtration, and expression in a unified manner. The same fundamental equations are simply adapted to the differing parameters and conditions related to the various modes of separation. As the system is flexible and adaptable to computational software, new developments can continually be added. Discussions of the various research projects in this report have been kept to a minimum and are principally qualitative. The length of the report would be excessive if each topic were covered in depth. Although the number of research topics may appear larger than one would expect, many are closely interconnected and reflect our philosophy of working in apparently diverse fields such as ceramics, mining, wastewater, food, chemical processing, and oil well operations.

  19. Reverse osmosis concentrate treatment by chemical oxidation and moving bed biofilm processes.

    PubMed

    Vendramel, S M R; Justo, A; González, O; Sans, C; Esplugas, S

    2013-01-01

    In the present work, four oxidation techniques were investigated (O3, O3/UV, H2O2/O3, O3/H2O2/UV) to pre-treat reverse osmosis (RO) concentrate before treatment in a moving-bed biofilm reactor (MBBR) system. Without previous oxidation, the MBBR was able to remove a small fraction of the chemical oxygen demand (COD) (5-20%) and dissolved organic carbon (DOC) (2-15%). When the concentrate was previously submitted to oxidation, DOC removal efficiencies in the MBBR increased to 40-55%. All the tested oxidation techniques improved concentrate biodegradability. The concentrate treated by the combined process (oxidation and MBBR) presented residual DOC and COD in the ranges of 6-12 and 25-41 mg L(-1), respectively. Nitrification of the RO concentrate, pre-treated by oxidation, was observed in the MBBR. Ammonium removal was comprised between 54 and 79%. The results indicate that the MBBR was effective for the treatment of the RO concentrate, previously submitted to oxidation, generating water with an improved quality.

  20. Phase sensitivity analysis of circadian rhythm entrainment.

    PubMed

    Gunawan, Rudiyanto; Doyle, Francis J

    2007-04-01

    As a biological clock, circadian rhythms evolve to accomplish a stable (robust) entrainment to environmental cycles, of which light is the most obvious. The mechanism of photic entrainment is not known, but two models of entrainment have been proposed based on whether light has a continuous (parametric) or discrete (nonparametric) effect on the circadian pacemaker. A novel sensitivity analysis is developed to study the circadian entrainment in silico based on a limit cycle approach and applied to a model of Drosophila circadian rhythm. The comparative analyses of complete and skeleton photoperiods suggest a trade-off between the contribution of period modulation (parametric effect) and phase shift (nonparametric effect) in Drosophila circadian entrainment. The results also give suggestions for an experimental study to (in)validate the two models of entrainment.

  1. The development of an integrated multistage fluid bed retorting process. Quarterly technical report, April 1, 1993--June 30, 1993

    SciTech Connect

    Carter, S.; Stehn, J.; Vego, A.

    1993-07-01

    This report summarizes the progress made on the development of an integrated multistage fluidized bed retorting process (KENTORT II) during the period of April 1, 1993 through June 30, 1993 under Cooperative Agreement No. DE-FC21-90MC27286 with the Morgantown Energy Technology Center, U.S. Department of Energy. The KENTORT II process includes integral fluidized bed zones for pyrolysis, gasification, and combustion of the oil shale. The purpose of this program is to design and test the KENTORT II process at the 50-lb/hr scale. The major activities for this quarter included: system leak proofing, cold flow testing, shake down of the data acquisition system, instrumentation verification, and preparation for hot operation. Once the tasks necessary for heat up are completed, shake down and operation of the Process Demonstration Unit will begin.

  2. Optimal entrainment of heterogeneous noisy neurons

    PubMed Central

    Wilson, Dan; Holt, Abbey B.; Netoff, Theoden I.; Moehlis, Jeff

    2015-01-01

    We develop a methodology to design a stimulus optimized to entrain nonlinear, noisy limit cycle oscillators with uncertain properties. Conditions are derived which guarantee that the stimulus will entrain the oscillators despite these uncertainties. Using these conditions, we develop an energy optimal control strategy to design an efficient entraining stimulus and apply it to numerical models of noisy phase oscillators and to in vitro hippocampal neurons. In both instances, the optimal stimuli outperform other similar but suboptimal entraining stimuli. Because this control strategy explicitly accounts for both noise and inherent uncertainty of model parameters, it could have experimental relevance to neural circuits where robust spike timing plays an important role. PMID:26074762

  3. [Performance and substrate inhibition kinetics model of nitritation process in inverse turbulent bed reactor].

    PubMed

    Jin, Ren-Cun; Yang, Guang-Feng; Ma, Chun; Zheng, Ping

    2011-01-01

    The performance of a nitritation inverse turbulent bed (ITB) reactor was tested and the substrate inhibition kinetics characteristics of the reactor were analyzed. The results showed that a rapid reactor startup could be realized within 20 d with a strategy that combined the biofilm attachment method named "precoating carrier treatment" and "rapid suspending sludge discharge", with the feeding strategy named "low strength, high load". When operated at a hydraulic retention time of 3 h and influent NH4(+) -N of 700 mg x L(-1), corresponding to a nitrogen loading rate of 5.60 kg x (m3 x d)(-1), a maximum NH4(+) -N removal rate of 4.25 kg x (m3 x d)(-1) was observed. The maximum NO2(-) -N production rate was as high as 3.70 kg x (m3 x d)(-1). Four inhibition kinetic models (Haldane, Edwards, Aiba and Luong) were analyzed through non-linear regression to represent the inhibitions caused by substrate of nitritation process and the parameters of models were gained, which were r(max) of 1.84 kg x (m3 x d)(-1), K(IH) of 97.4 mg x L(-1) and K(m) of 0.188 mg x L(-1) for Haldane model, and r(max) of 1.83 kg x (m3 x d)(-1) and K(IA) of 114 mg x L(-1) for Aiba model. It was proposed that Haldane and Aiba models well fitted the process data harvested in the ITB reactor.

  4. Comparison of entrainment in constant volume and constant flux dense currents over sloping bottoms

    NASA Astrophysics Data System (ADS)

    Bhaganagar, K.; Nayamatullah, M.; Cenedese, C.

    2014-12-01

    Three dimensional high resolution large eddy simulations (LES) are employed to simulate lock-exchange and constant flux dense flows over inclined surface with the aim of investigating, visualizing and describing the turbulent structure and the evolution of bottom-propagating compositional density current at the channel bottom. The understanding of dynamics of density current is largely determined by the amount of interfacial mixing or entrainment between the ambient and dense fluids. No previous experimental or numerical studies have been done to estimate entrainment in classical lock-exchange system. The differences in entrainment between the lock-exchange and constant flux are explored. Comparing the results of flat bed with inclined surface results, flow exhibits significant differences near the leading edge or nose of the front of the density currents due to inclination of surface. Further, the instabilities are remarkably enhanced resulting Kelvin-Helmholtz and lobe-cleft type of instabilities arises much earlier in time. In this study, a brief analysis of entrainment on lock-exchange density current is presented using different bed slopes and a set of reduced gravity values (g'). We relate the entrainment value with different flow parameters such as Froude number (Fr) and Reynolds number (Re).

  5. Air Entrainment and Thermal Evolution of Pyroclastic Density Currents at Tungurahua, Ecuador

    NASA Astrophysics Data System (ADS)

    Benage, M. C.; Dufek, J.; Mothes, P. A.

    2015-12-01

    The entrainment of air into pyroclastic density currents (PDCs) impacts the thermal profile and evolution of the current. However, the associated hazards and opaqueness of PDCs make it difficult to discern internal dynamics and entrainment through direct observations. In this work, we use a three-dimensional multiphase Eulerian-Eulerian-Lagrangian (EEL) model, deposit descriptions, and pyroclast field data, such as paleomagnetic and rind thickness, to study the entrainment efficiency and thus the thermal history of PDCs down the Juive Grande quebrada during the August 16-17th 2006 eruption of Tungurahua volcano. We conclude that 1) the efficient entrainment of ambient air cools the nose and upper portion of the PDCs by 30-60% of the original temperature, 2) PDCs with an initial temperature of 727 °C are on average more efficient at entraining ambient air than PDCs with an initial temperature of 327 °C, 3) the channelized PDCs develop a particle concentration gradient with a concentrated bed load region and suspended load region that leads to a large vertical temperature gradient, and 4) observations and pyroclast temperatures and textures suggest that the PDCs had temperatures greater than 327 °C in the bed load region while the upper, exterior portion of the currents cooled down to temperatures less than 100 °C. By combining field data and numerical models, the structure and dynamics of a PDC can be deduced for these relatively common small volume PDCs.

  6. Dynamic evaluation of a fixed bed anaerobic digestion process in response to organic overloads and toxicant shock loads.

    PubMed

    Dupla, M; Conte, T; Bouvier, J C; Bernet, N; Steyer, J P

    2004-01-01

    This paper details a dynamic evaluation of a 1 m3 fixed bed anaerobic digestion reactor in response to organic overloads and toxicant shock loads. Raw industrial wine distillery wastewater was used as a reference substrate and several disturbances were applied to the process: (i) organic overloads with and without pH regulation in the feeding line, (ii) adding of ammonia in the input wastewater. The purpose of this study was to assess, using on-line instrumentation, the robustness of a fixed bed anaerobic digester. Anaerobic digestion processes have the reputation of being difficult to operate and prone to process instability due to external disturbances and the objective of this study was to demonstrate the possibility of such a reactor configuration for industrial use.

  7. Sorption processes affecting arsenic solubility in oxidized surface sediments from Tulare Lake Bed, California

    USGS Publications Warehouse

    Gao, S.; Goldberg, S.; Herbel, M.J.; Chalmers, A.T.; Fujii, R.; Tanji, K.K.

    2006-01-01

    Elevated concentrations of arsenic (As) in shallow groundwater in Tulare Basin pose an environmental risk because of the carcinogenic properties of As and the potential for its migration to deep aquifers that could serve as a future drinking water source. Adsorption and desorption are hypothesized to be the major processes controlling As solubility in oxidized surface sediments where arsenate [As(V)] is dominant. This study examined the relationship between sorption processes and arsenic solubility in shallow sediments from the dry Tulare Lake bed by determining sorption isotherms, pH effect on solubility, and desorption-readsorption behavior (hysteresis), and by using a surface complexation model to describe sorption. The sediments showed a high capacity to adsorb As(V). Estimates of the maximum adsorption capacity were 92 mg As kg- 1 at pH 7.5 and 70 mg As kg- 1 at pH 8.5 obtained using the Langmuir adsorption isotherm. Soluble arsenic [> 97% As(V)] did not increase dramatically until above pH 10. In the native pH range (7.5-8.5), soluble As concentrations were close to the lowest, indicating that As was strongly retained on the sediment. A surface complexation model, the constant capacitance model, was able to provide a simultaneous fit to both adsorption isotherms (pH 7.5 and 8.5) and the adsorption envelope (pH effect on soluble As), although the data ranges are one order of magnitude different. A hysteresis phenomenon between As adsorbed on the sediment and As in solution phase was observed in the desorption-readsorption processes and differs from conventional hysteresis observed in adsorption-desorption processes. The cause is most likely due to modification of adsorbent surfaces in sediment samples upon extensive extractions (or desorption). The significance of the hysteresis phenomenon in affecting As solubility and mobility may be better understood by further microscopic studies of As interaction mechanisms with sediments subjected to extensive leaching

  8. Cryogenic fractionator gas as stripping gas of fines slurry in a coking and gasification process

    DOEpatents

    DeGeorge, Charles W.

    1981-01-01

    In an integrated coking and gasification process wherein a stream of fluidized solids is passed from a fluidized bed coking zone to a second fluidized bed and wherein entrained solid fines are recovered by a scrubbing process and wherein the resulting solids-liquid slurry is stripped with a stripping gas to remove acidic gases, at least a portion of the stripping gas comprises a gas comprising hydrogen, nitrogen and methane separated from the coker products.

  9. Development of a trickle bed reactor of electro-Fenton process for wastewater treatment.

    PubMed

    Lei, Yangming; Liu, Hong; Shen, Zhemin; Wang, Wenhua

    2013-10-15

    To avoid electrolyte leakage and gas bubbles in the electro-Fenton (E-Fenton) reactors using a gas diffusion cathode, we developed a trickle bed cathode by coating a layer composed of carbon black and polytetrafluoroethylene (C-PTFE) onto graphite chips instead of carbon cloth. The trickle bed cathode was optimized by single-factor and orthogonal experiments, in which carbon black, PTFE, and a surfactant were considered as the determinant of the performance of graphite chips. In the reactor assembled by the trickle bed cathode, H2O2 was generated with a current of 0.3A and a current efficiency of 60%. This performance was attributed to the fine distribution of electrolyte and air, as well as the effective oxygen transfer from the gas phase to the electrolyte-cathode interface. In terms of H2O2 generation and current efficiency, the developed trickle bed reactor had a performance comparable to that of the conventional E-Fenton reactor using a gas diffusion cathode. Further, 123 mg L(-1) of reactive brilliant red X-3B in aqueous solution was decomposed in the optimized trickle bed reactor as E-Fenton reactor. The decolorization ratio reached 97% within 20 min, and the mineralization reached 87% within 3h.

  10. Fluvial processes and local lithology controlling abundance, structure, and composition of mussel beds

    PubMed Central

    Vannote, Robin L.; Minshall, G. Wayne

    1982-01-01

    In the Salmon River Canyon, Idaho, the fresh-water pearl mussel, Margaritifera falcata, attains maximum density and age in river reaches where large block-boulders structurally stabilize cobbles and interstitial gravels. We hypothesize that block-boulders prevent significant bed scour during major floods, and these boulder-sheltered mussel beds, although rare, may be critical for population recruitment elsewhere within the river, especially after periodic flood scour of less protected mussel habitat. Mussel shells in Indian middens adjacent to these boulder-stabilized areas suggest that prehistoric tribes selectively exploited the high-density old-aged mussel beds. Locally, canyon reaches are aggrading with sand and gravel, and M. falcata is being replaced by Gonidea angulata. PMID:16593208

  11. Using Ultrasound to Characterize Pulp Slurries with Entrained Air

    SciTech Connect

    Bamberger, Judith A.

    2006-08-06

    The development of fast and practical methods for inspecting fiber suspensions is of great interest in the paper making industry. For process control and paper quality prediction, several elements of the refining process during paper making must be accurately monitored, including specific fiber properties, weight percent fiber (composition), degree of refining, amount of solids, and entrained air content. The results of previous ultrasonic studies applied to wood pulp provide guidance that ultrasound attenuation is information rich, and it does potentially provide a tool for consistency measurement. Ultrasound has the ability to penetrate dense suspensions such as wood pulp slurries. It is has been shown, in some studies, that ultrasound is sensitive to degree of refining. The effects of entrained air, additives, the origin and treatment of the fibers do however all influence the measured data. A series of measurements were made with hardwood and softwood slurries to evaluate the ability of measuring pulp consistency, solids, and entrained air. The attenuation through the slurry was measured as the ultrasound travels from one transducer through the slurry to the other. The measurements identified the presence of entrained air in the pulp samples. To better understand the effects of air, measurements were made at increasing pressures to show how increased pressure reduced the amount of air observed in the spectrum.

  12. Development of a visiometric process analyzer for real-time monitoring of bottom spray fluid-bed coating.

    PubMed

    Liew, Celine Valeria; Wang, Li Kun; Wan Sia Heng, Paul

    2010-01-01

    Particle recirculation within the partition column is a major source of process variability in the bottom spray fluid-bed coating process. However, its locality and complex nature make it hidden from the operator. The aim of this study was to take snapshots of the process by employing a visiometric process analyzer based on high-speed imaging and ensemble correlation particle image velocimetry (PIV) to quantify particle recirculation. High-speed images of particles within the partition column of a bottom spray fluid-bed coater were captured and studied by morphological image processing and ensemble correlation PIV. Particle displacement probability density function (PDF) obtained from ensemble correlation PIV was consistent with validation experiments using an image tracking method. Particle displacement PDF was further resolved into particle velocity magnitude and particle velocity orientation histograms, which gave information about particle recirculation probability, thus quantifying the main source of process variability. Deeper insights into particle coating process were obtained and better control of coat uniformity can thus be achieved with use of the proposed visiometric process analyzer. The concept of visiometric process analyzers was proposed and their potential applications in pharmaceutical processes were further discussed. PMID:19504576

  13. Nitrogen removal in micro-polluted surface water by the combined process of bio-filter and ecological gravel bed.

    PubMed

    Sheng-Bing, He; Jian-Wen, Gao; Xue-Chu, Chen; Ding-Li, Dai

    2013-01-01

    Nitrogen removal in micro-polluted surface water by the combined process of a bio-filter and an ecological gravel bed was studied. Sodium acetate was added into micro-polluted surface water as carbon source and the nitrogen removal under different C/N ratio, hydraulic load and temperature were investigated. The results showed that the variations in C/N ratio, hydraulic load and temperature have significant influence on nitrogen removal in bio-filter. It was found that the denitrification rate was above 90% when C/N ratio reached 10; also, the denitrification was inhibited at low water temperature (2-10 °C); at the condition of water temperature above 20 °C, C/N ratio 10, hydraulic load 8 m(3)/(m(2) h), the combined process obtained the nitrogen removal of more than 90%, and the residual organics could be removed in ecological gravel bed.

  14. Integration and testing of hot desulfurization and entrained-flow gasification for power generation systems. Phase 2, Process optimization: Volume 1, Program summary and PDU operations

    SciTech Connect

    Robin, A.M.; Kassman, J.S.; Leininger, T.F.; Wolfenbarger, J.K.; Wu, C.M.; Yang, P.P.

    1991-09-01

    This second Topical Report describes the work that was completed between January 1, 1989 and December 31, 1990 in a Cooperative Agreement between Texaco and the US Department of Energy that began on September 30, 1987. During the period that is covered in this report, the development and optimization of in-situ and external desulfurization processes were pursued. The research effort included bench scale testing, PDU scoping tests, process economic studies and advanced instrument testing. Two bench scale studies were performed at the Research Triangle Institute with zinc titanate sorbent to obtain data on its cycle life, sulfur capacity, durability and the effect of chlorides. These studies quantify sulfur capture during simulated air and oxygen-blown gasification for two zinc titanate formulations. Eight PDU runs for a total of 20 days of operation were conducted to evaluate the performance of candidate sorbents for both in-situ and external desulfurization. A total of 47 tests were completed with oxygen and air-blown gasification. Candidate sorbents included iron oxide for in-situ desulfurization and calcium based and mixed metal oxides for external desulfurization. Gasifier performance and sorbent sulfur capture are compared for both air-blown and oxygen-blown operation.

  15. Numerical analysis of the process of combustion and gasification of the polydisperse coke residue of high-ash coal under pressure in a fluidized bed

    SciTech Connect

    A.Y. Maistrenko; V.P. Patskov; A.I. Topal; T.V. Patskova

    2007-09-15

    A numerical analysis of the process of 'wet' gasification of high-ash coal under pressure in a low-temperature fluidized bed has been performed. The applicability of the previously developed computational model, algorithm, and program for the case under consideration has been noted. The presence of 'hot spots' (short-time local heatings) at different points of the bed has been confirmed.

  16. The neurochemical basis of photic entrainment of the circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Rea, Michael A.; Buckley, Becky; Lutton, Lewis M.

    1992-01-01

    Circadian rhythmicity in mammals is controlled by the action of a light-entrainable hypothalamus, in association with two cell clusters known as the supra chiasmatic nuclei (SCN). In the absence of temporal environmental clues, this pacemaker continues to measure time by an endogenous mechanism (clock), driving biochemical, physiological, and behavioral rhythms that reflect the natural period of the pacemaker oscillation. This endogenous period usually differs slightly from 24 hours (i.e., circadian). When mammals are maintained under a 24 hour light-dark (LD) cycle, the pacemaker becomes entrained such that the period of the pacemaker oscillation matches that of the LD cycle. Potentially entraining photic information is conveyed to the SCN via a direct retinal projection, the retinohypothalamic tract (RHT). RHT neurotransmission is thought to be mediated by the release of excitatory amino acids (EAA) in the SCN. In support of this hypothesis, recent experiments using nocturnal rodents have shown that EAA antagonists block the effects of light on pacemaker-driven behavioral rhythms, and attenuate light induced gene expression in SCN cells. An understanding of the neurochemical basis of the photic entrainment process would facilitate the development of pharmacological strategies for maintaining synchrony among shift workers in environments, such as the Space Station, which provide unreliable or conflicting temporal photic clues.

  17. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

    DOE PAGESBeta

    Lu, Chunsong; Liu, Yangang; Niu, Shengjie; Endo, Satoshi

    2014-12-17

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasingmore » scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.« less

  18. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

    SciTech Connect

    Lu, Chunsong; Liu, Yangang; Niu, Shengjie; Endo, Satoshi

    2014-12-17

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasing scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.

  19. Bed Stability and Debris Flow Erosion: A Dynamic "Shields Criterion" Associated with Bed Structure

    NASA Astrophysics Data System (ADS)

    Longjas, A.; Hill, K. M.

    2015-12-01

    Debris flows are mass movements that play an important role in transporting sediment from steep uplands to rivers at lower slopes. As the debris flow moves downstream, it entrains materials such as loose boulders, gravel, sand and mud deposited locally by shorter flows such as slides and rockfalls. To capture the conditions under which debris flows entrain bed sediment, some models use something akin to the Shields' criterion and an excess shear stress of the flow. However, these models typically neglect granular-scale effects in the bed which can modify the conditions under which a debris flow is erosional or depositional. For example, it is well known that repeated shearing causes denser packing in loose dry soils, which undoubtedly changes their resistance to shear. Here, we present laboratory flume experiments showing that the conditions for entrainment by debris flows is significantly dependent on the aging of an erodible bed even for narrowly distributed spherical particles. We investigate this quantitatively using particle tracking measurements to quantify instantaneous erosion rates and the evolving bed structure or "fabric". With progressive experiments we find a signature that emerges in the bed fabric that is correlated with an increasing apparent "fragility" of the bed. Specifically, a system that is originally depositional may become erosional after repeated debris flow events, and an erodible bed becomes increasingly erodible with repeated flows. We hypothesize that related effects of bed aging at the field scale may be partly responsible for the increasing destructiveness of secondary flows of landslides and debris flows.

  20. Fine sediment erosion rate in immobile gravel bed

    NASA Astrophysics Data System (ADS)

    Tarekegn, T. H.

    2015-12-01

    The dynamics of fine sediment transport in immobile gravel bed is a complex process and is a common phenomenon downstream of dams during dam removal and flushing operations. Despite many developments in the field, the direct measurement of fine sediment erosion (entrainment) rates in immobile coarse beds remains challenging. We developed a new approach for measurement of fine sediment erosion rate in coarse immobile bed in laboratory experiment. The method uses single laser line, a video camera and a reflective mirror. It allows a non-intrusive, fast and accurate measurement of fine sediment erosion rate in running water and non-equilibrium transport conditions. The measurement method was conducted for flow depth that ranges from 3.0 cm to 8.0 cm. We present procedures developed to extract laser lines from series of images captured at high temporal resolution and to estimate rapid evolution of fine sediment erosion depth within the roughness layer of the immobile gravel bed. With the use of a reflective mirror the depth of erosion can be measured with sub-millimeter (350μm) resolution. The results of the measurements are used to describe vertical profile of fine sediment erosion rate in the gravel roughness layer and its spatial heterogeneity. The spatial pattern of erosion rates shows good agreement with gravel bed turbulent flow structures.

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

    SciTech Connect

    Rokkam, Ram

    2012-01-01

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

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

    PubMed

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

    2014-01-01

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

  3. Effect of different carriers and operating parameters on degradation of flax wastewater by fluidized-bed Fenton process.

    PubMed

    Chen, Mengtian; Ren, Hongqiang; Ding, Lili; Gao, Baotian

    2015-01-01

    This investigation evaluates the effectiveness of a fluidized-bed Fenton process in treating flax wastewater. Flax wastewater was taken from a paper-making factory in a secondary sedimentation tank effluent of a paper-making factory in Hebei. The performance of three carriers (SiO2, Al2O3, Fe2O3) used in the reactor was compared, and the effects of different operational conditions, and Fenton reagent concentrations were studied. Experimental results indicated that SiO2 was the most appropriate carrier in the system. The dose of Fe2+ and H2O2 was a significant operating factor in the degradation progress. The bed expansion was considered to be another factor influencing the treatment effect. Under the appropriate conditions (300 mg/L Fe2+, 600 mg/L H2O2, and 74.07 g/L SiO2 as the carrier, at pH=3, 50% bed expansion), the highest removal rate of total organic carbon (TOC) and color was 89% and 94%, respectively. The article also discussed the process of the colority removal of flax wastewater and the kinetics of TOC removal.

  4. Effect of different carriers and operating parameters on degradation of flax wastewater by fluidized-bed Fenton process.

    PubMed

    Chen, Mengtian; Ren, Hongqiang; Ding, Lili; Gao, Baotian

    2015-01-01

    This investigation evaluates the effectiveness of a fluidized-bed Fenton process in treating flax wastewater. Flax wastewater was taken from a paper-making factory in a secondary sedimentation tank effluent of a paper-making factory in Hebei. The performance of three carriers (SiO2, Al2O3, Fe2O3) used in the reactor was compared, and the effects of different operational conditions, and Fenton reagent concentrations were studied. Experimental results indicated that SiO2 was the most appropriate carrier in the system. The dose of Fe2+ and H2O2 was a significant operating factor in the degradation progress. The bed expansion was considered to be another factor influencing the treatment effect. Under the appropriate conditions (300 mg/L Fe2+, 600 mg/L H2O2, and 74.07 g/L SiO2 as the carrier, at pH=3, 50% bed expansion), the highest removal rate of total organic carbon (TOC) and color was 89% and 94%, respectively. The article also discussed the process of the colority removal of flax wastewater and the kinetics of TOC removal. PMID:26067494

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

    PubMed

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

    2014-01-01

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

  6. Temperature compensation and entrainment in circadian rhythms

    NASA Astrophysics Data System (ADS)

    Bodenstein, C.; Heiland, I.; Schuster, S.

    2012-06-01

    To anticipate daily variations in the environment and coordinate biological activities into a daily cycle many organisms possess a circadian clock. In the absence of external time cues the circadian rhythm persists with a period of approximately 24 h. The clock phase can be shifted by single pulses of light, darkness, chemicals, or temperature and this allows entrainment of the clock to exactly 24 h by cycles of these zeitgebers. On the other hand, the period of the circadian rhythm is kept relatively constant within a physiological range of constant temperatures, which means that the oscillator is temperature compensated. The mechanisms behind temperature compensation and temperature entrainment are not fully understood, neither biochemically nor mathematically. Here, we theoretically investigate the interplay of temperature compensation and entrainment in general oscillatory systems. We first give an analytical treatment for small temperature shifts and derive that every temperature-compensated oscillator is entrainable to external small-amplitude temperature cycles. Temperature compensation ensures that this entrainment region is always centered at the endogenous period regardless of possible seasonal temperature differences. Moreover, for small temperature cycles the entrainment region of the oscillator is potentially larger for rectangular pulses. For large temperature shifts we numerically analyze different circadian clock models proposed in the literature with respect to these properties. We observe that for such large temperature shifts sinusoidal or gradual temperature cycles allow a larger entrainment region than rectangular cycles.

  7. Entrainment rates and microphysics in POST stratocumulus

    NASA Astrophysics Data System (ADS)

    Gerber, H.; Frick, G.; Malinowski, Szymon P.; Jonsson, H.; Khelif, D.; Krueger, Steven K.

    2013-11-01

    An aircraft field study (POST; Physics of Stratocumulus Top) was conducted off the central California coast in July and August 2008 to deal with the known difficulty of measuring entrainment rates in the radiatively important stratocumulus (Sc) prevalent in that area. The Center for Interdisciplinary Remotely-Piloted Aircraft Studies Twin Otter research aircraft flew 15 quasi-Lagrangian flights in unbroken Sc and carried a full complement of probes including three high-data-rate probes: ultrafast temperature probe, particulate volume monitor probe, and gust probe. The probes' colocation near the nose of the Twin Otter permitted estimation of entrainment fluxes and rates with an in-cloud resolution of 1 m. Results include the following: Application of the conditional sampling variation of classical mixed layer theory for calculating the entrainment rate into cloud top for POST flights is shown to be inadequate for most of the Sc. Estimated rates resemble previous results after theory is modified to take into account both entrainment and evaporation at cloud top given the strong wind shear and mixing at cloud top. Entrainment rates show a tendency to decrease for large shear values, and the largest rates are for the smallest temperature jumps across the inversion. Measurements indirectly suggest that entrained parcels are primarily cooled by infrared flux divergence rather than cooling from droplet evaporation, while detrainment at cloud top causes droplet evaporation and cooling in the entrainment interface layer above cloud top.

  8. The performative pleasure of imprecision: a diachronic study of entrainment in music performance.

    PubMed

    Geeves, Andrew; McIlwain, Doris J; Sutton, John

    2014-01-01

    This study focuses in on a moment of live performance in which the entrainment amongst a musical quartet is threatened. Entrainment is asymmetric in so far as there is an ensemble leader who improvises and expands the structure of a last chorus of a piece of music beyond the limits tacitly negotiated during prior rehearsals and performances. Despite the risk of entrainment being disturbed and performance interrupted, the other three musicians in the quartet follow the leading performer and smoothly transition into unprecedented performance territory. We use this moment of live performance to work back through the fieldwork data, building a diachronic study of the development and bases of entrainment in live music performance. We introduce the concept of entrainment and profile previous theory and research relevant to entrainment in music performance. After outlining our methodology, we trace the evolution of the structure of the piece of music from first rehearsal to final performance. Using video clip analysis, interviews and field notes we consider how entrainment shaped and was shaped by the moment of performance in focus. The sense of trust between quartet musicians is established through entrainment processes, is consolidated via smooth adaptation to the threats of disruption. Non-verbal communicative exchanges, via eye contact, gesture, and spatial proximity, sustain entrainment through phase shifts occurring swiftly and on the fly in performance contexts. These exchanges permit smooth adaptation promoting trust. This frees the quartet members to play with the potential disturbance of equilibrium inherent in entrained relationships and to play with this tension in an improvisatory way that enhances audience engagement and the live quality of performance.

  9. The performative pleasure of imprecision: a diachronic study of entrainment in music performance

    PubMed Central

    Geeves, Andrew; McIlwain, Doris J.; Sutton, John

    2014-01-01

    This study focuses in on a moment of live performance in which the entrainment amongst a musical quartet is threatened. Entrainment is asymmetric in so far as there is an ensemble leader who improvises and expands the structure of a last chorus of a piece of music beyond the limits tacitly negotiated during prior rehearsals and performances. Despite the risk of entrainment being disturbed and performance interrupted, the other three musicians in the quartet follow the leading performer and smoothly transition into unprecedented performance territory. We use this moment of live performance to work back through the fieldwork data, building a diachronic study of the development and bases of entrainment in live music performance. We introduce the concept of entrainment and profile previous theory and research relevant to entrainment in music performance. After outlining our methodology, we trace the evolution of the structure of the piece of music from first rehearsal to final performance. Using video clip analysis, interviews and field notes we consider how entrainment shaped and was shaped by the moment of performance in focus. The sense of trust between quartet musicians is established through entrainment processes, is consolidated via smooth adaptation to the threats of disruption. Non-verbal communicative exchanges, via eye contact, gesture, and spatial proximity, sustain entrainment through phase shifts occurring swiftly and on the fly in performance contexts. These exchanges permit smooth adaptation promoting trust. This frees the quartet members to play with the potential disturbance of equilibrium inherent in entrained relationships and to play with this tension in an improvisatory way that enhances audience engagement and the live quality of performance. PMID:25400567

  10. A New Dry Flue Gas Desulfurization Process-Underfeed Circulating Spouted Bed

    NASA Astrophysics Data System (ADS)

    Tao, M.; Jin, B. S.; Yang, Y. P.

    Applying an underfeed system, the underfeed circulating spouted bed was designed as a desulfurization reactor. The main objective of the technology is to improve the mixing effect and distribution uniformity of solid particles, and therefore to advance the desulfurization efficiency and calcium utility. In this article, a series of experimental studies were conducted to investigate the fluidization behavior of the solid-gas two-phase flow in the riser. The results show that the technology can distinctly improve the distribution of gas velocity and particle flux on sections compared with the facefeed style. Analysis of pressure fluctuation signals indicates that the operation parameters have significant influence on the flow field in the reaction bed. The existence of injecting flow near the underfeed nozzle has an evident effect on strengthening the particle mixing.

  11. Review on Biomass Torrefaction Process and Product Properties and Design of Moving Bed Torrefaction System Model Development

    SciTech Connect

    Jaya Shankar Tumuluru; Christopher T. Wright; Shahab Sokhansanj

    2011-08-01

    A Review on Torrefaction Process and Design of Moving Bed Torrefaction System for Biomass Processing Jaya Shankar Tumuluru1, Shahab Sokhansanj2 and Christopher T. Wright1 Idaho National Laboratory Biofuels and Renewable Energy Technologies Department Idaho Falls, Idaho 83415 Oak Ridge National Laboratory Bioenergy Resource and Engineering Systems Group Oak Ridge, TN 37831 Abstract Torrefaction is currently developing as an important preprocessing step to improve the quality of biomass in terms of physical properties, and proximate and ultimate composition. Torrefaction is a slow heating of biomass in an inert or reduced environment to a maximum temperature of 300 C. Torrefaction can also be defined as a group of products resulting from the partially controlled and isothermal pyrolysis of biomass occurring in a temperature range of 200-230 C and 270-280 C. Thus, the process can also be called a mild pyrolysis as it occurs at the lower temperature range of the pyrolysis process. At the end of the torrefaction process, a solid uniform product with lower moisture content and higher energy content than raw biomass is produced. Most of the smoke-producing compounds and other volatiles are removed during torrefaction, which produces a final product that will have a lower mass but a higher heating value. There is a lack of literature on the design aspects of torrefaction reactor and a design sheet for estimating the dimensions of the torrefier based on capacity. This study includes (a) conducting a detailed review on the torrefaction of biomass in terms of understanding the process, product properties, off-gas compositions, and methods used, and (b) to design a moving bed torrefier, taking into account the basic fundamental heat and mass transfer calculations. Specific objectives include calculating the dimensions like diameter and height of the moving packed bed torrefier for different capacities ranging from 25-1000 kg/hr, designing the heat loads and gas flow rates, and

  12. Geochemical processes of formations of red-bed associated Cu-Co deposit at Kamoto, Zaire

    SciTech Connect

    Hoy, L.D.; Ohmoto, H.; Rose, A.W.

    1985-01-01

    In the stratiform Cu-Co deposit at Kamoto, ore minerals occur in layers conformable to bedding, or as replacement of nodular and/or bedded dolomite within marine to littoral sediments overlying a thick continental red-bed sequence. delta/sup 13/C and delta/sup 13/O values of more than 70 dolomite samples from the red-bed, ore zone and unmineralized hangingwall sediments were determined to be -9 to +3 per thousand (PDB) and + 7 to +24 per thousand(SMOW), respectively. The delta/sup 13/C values correlate negatively with the amount of relict organic matter in the samples. Poor correlation between delta/sup 13/C and delta/sup 18/O indicates that dolomitization incorporating oxidized organic carbon occurred through a large temperature range. delta/sup 34/S values of about 70 ore sulfide samples range from -15 to +17 per thousand (CDT), correlating positively with both total S content of the samples and the delta/sup 13/C of associated dolomite. The isotopic data, the overgrowth and replacement textures observed among ore and gangue minerals, and the results of thermochemical calculations on the solubility and stability of the sulfides suggest that: (1) less than 30% of the sulfide sulfur in the deposit was fixed as bacteriogenic pyrite during early diagenesis; and (2) the Cu and Co sulfides were formed by later reaction between Cu-, Co- and SO/sub 4/-bearing hot (50-200/sup 0/C.) brines and the diagenetic pyrite, augmented by additional sulfate reduction through organic matter oxidation.

  13. Doing Duo – a case study of entrainment in William Forsythe’s choreography “Duo”

    PubMed Central

    Waterhouse, Elizabeth; Watts, Riley; Bläsing, Bettina E.

    2014-01-01

    Entrainment theory focuses on processes in which interacting (i.e., coupled) rhythmic systems stabilize, producing synchronization in the ideal sense, and forms of phase related rhythmic coordination in complex cases. In human action, entrainment involves spatiotemporal and social aspects, characterizing the meaningful activities of music, dance, and communication. How can the phenomenon of human entrainment be meaningfully studied in complex situations such as dance? We present an in-progress case study of entrainment in William Forsythe’s choreography Duo, a duet in which coordinated rhythmic activity is achieved without an external musical beat and without touch-based interaction. Using concepts of entrainment from different disciplines as well as insight from Duo performer Riley Watts, we question definitions of entrainment in the context of dance. The functions of chorusing, turn-taking, complementary action, cues, and alignments are discussed and linked to supporting annotated video material. While Duo challenges the definition of entrainment in dance as coordinated response to an external musical or rhythmic signal, it supports the definition of entrainment as coordinated interplay of motion and sound production by active agents (i.e., dancers) in the field. Agreeing that human entrainment should be studied on multiple levels, we suggest that entrainment between the dancers in Duo is elastic in time and propose how to test this hypothesis empirically. We do not claim that our proposed model of elasticity is applicable to all forms of human entrainment nor to all examples of entrainment in dance. Rather, we suggest studying higher order phase correction (the stabilizing tendency of entrainment) as a potential aspect to be incorporated into other models. PMID:25374522

  14. Process for purifying geothermal steam

    DOEpatents

    Li, Charles T.

    1980-01-01

    Steam containing hydrogen sulfide is purified and sulfur recovered by passing the steam through a reactor packed with activated carbon in the presence of a stoichiometric amount of oxygen which oxidizes the hydrogen sulfide to elemental sulfur which is adsorbed on the bed. The carbon can be recycled after the sulfur has been recovered by vacuum distillation, inert gas entrainment or solvent extraction. The process is suitable for the purification of steam from geothermal sources which may also contain other noncondensable gases.

  15. Process for purifying geothermal steam

    DOEpatents

    Li, C.T.

    Steam containing hydrogen sulfide is purified and sulfur recovered by passing the steam through a reactor packed with activated carbon in the presence of a stoichiometric amount of oxygen which oxidizes the hydrogen sulfide to elemental sulfur which is adsorbed on the bed. The carbon can be recycled after the sulfur has been recovered by vacuum distillation, inert gas entrainment or solvent extraction. The process is suitable for the purification of steam from geothermal sources which may also contain other noncondensable gases.

  16. Functionalization of polymers using an atmospheric plasma jet in a fluidized bed reactor and the impact on SLM-processes

    SciTech Connect

    Sachs, M. Schmitt, A. Schmidt, J. Peukert, W. Wirth, K-E

    2014-05-15

    In order to improve thermoplastics (e.g. Polyamide, Polypropylene and Polyethylene) for Selective Laser Beam Melting (SLM) processes a new approach to functionalize temperature sensitive polymer powders in a large scale is investigated. This is achieved by combining an atmospheric pressure plasma jet and a fluidized bed reactor. Using pressurized air as the plasma gas, radicals like OH* are created. The functionalization leads to an increase of the hydrophilicity of the treated polymer powder without changing the bulk properties. Using the polymers in a SLM process to build single layers of melted material leads to an improvement of the melted layers.

  17. Functionalization of polymers using an atmospheric plasma jet in a fluidized bed reactor and the impact on SLM-processes

    NASA Astrophysics Data System (ADS)

    Sachs, M.; Schmitt, A.; Schmidt, J.; Peukert, W.; Wirth, K.-E.

    2014-05-01

    In order to improve thermoplastics (e.g. Polyamide, Polypropylene and Polyethylene) for Selective Laser Beam Melting (SLM) processes a new approach to functionalize temperature sensitive polymer powders in a large scale is investigated. This is achieved by combining an atmospheric pressure plasma jet and a fluidized bed reactor. Using pressurized air as the plasma gas, radicals like OH* are created. The functionalization leads to an increase of the hydrophilicity of the treated polymer powder without changing the bulk properties. Using the polymers in a SLM process to build single layers of melted material leads to an improvement of the melted layers.

  18. Modern processes controlling the sea bed sediment formation in Barents Sea

    NASA Astrophysics Data System (ADS)

    Balanyuk, I.; Dmitrievsky, A.; Shapovalov, S.; Chaikina, O.; Akivis, T.

    2009-04-01

    The Barents Sea is one of the key regions for understanding of the postglacial history of the climate and circulation of the World Ocean. There are the limits of warm North Atlantic waters penetration to the Arctic and a zone of interaction between Atlantic and Arctic waters. The Barents Se's limits are the deep Norwegian Sea in the West, the Spitsbergen Island and the Franz Josef Land and the deep Nansen trough in the North, the Novaya Zemlya archipelago in the East and the North shore of Europe in the South. An analysis of Eurasian-Arctic continental margin shows correspondence between the rift systems of the shelf with those of the ocean. This relation can be observed in the central Arctic region. All the rift systems underlying the sediment basin are expressed in the sea bed relief as spacious and extensive graben valleys burnished by lobes. Two transverse trenches cross both shelf and continental slope, namely the Medvezhinsky trench between Norway and Spitsbergen in the West and the Franz Victoria trench between Spitsbergen and the Franz Josef Land in the North. The Barents and the Kara Seas are connected by the Kara Gate Strait and wide transverse trough of Saint Anna in the North-West. The recent assessment of the eolian solid sediment supply to the Barents Sea is about 0.904 tons. The Barents Sea as a whole should be considered as "starving" in terms of its feeding with solid sediment matter. Observations show the considerable part of the sea bottom to be free of Holocene sediment cover. The more ancient Quaternary units or bedrock can be seen at the bottom surface. This phenomenon is the most typical for arches of relatively shallow elevations. Thick accumulations of new sediments are connected with fjords. The amount of sea ice delivered from the Barents Sea to the Arctic Ocean is 35 km3 a year. This value should be added by iceberg delivery from the North island of Novaya Zemlya, the Franz Josef Land, the Spitsbergen Island and North Norway but most of

  19. Entrained neural oscillations in multiple frequency bands comodulate behavior

    PubMed Central

    Henry, Molly J.; Herrmann, Björn

    2014-01-01

    Our sensory environment is teeming with complex rhythmic structure, to which neural oscillations can become synchronized. Neural synchronization to environmental rhythms (entrainment) is hypothesized to shape human perception, as rhythmic structure acts to temporally organize cortical excitability. In the current human electroencephalography study, we investigated how behavior is influenced by neural oscillatory dynamics when the rhythmic fluctuations in the sensory environment take on a naturalistic degree of complexity. Listeners detected near-threshold gaps in auditory stimuli that were simultaneously modulated in frequency (frequency modulation, 3.1 Hz) and amplitude (amplitude modulation, 5.075 Hz); modulation rates and types were chosen to mimic the complex rhythmic structure of natural speech. Neural oscillations were entrained by both the frequency modulation and amplitude modulation in the stimulation. Critically, listeners’ target-detection accuracy depended on the specific phase–phase relationship between entrained neural oscillations in both the 3.1-Hz and 5.075-Hz frequency bands, with the best performance occurring when the respective troughs in both neural oscillations coincided. Neural-phase effects were specific to the frequency bands entrained by the rhythmic stimulation. Moreover, the degree of behavioral comodulation by neural phase in both frequency bands exceeded the degree of behavioral modulation by either frequency band alone. Our results elucidate how fluctuating excitability, within and across multiple entrained frequency bands, shapes the effective neural processing of environmental stimuli. More generally, the frequency-specific nature of behavioral comodulation effects suggests that environmental rhythms act to reduce the complexity of high-dimensional neural states. PMID:25267634

  20. Advanced development of a pressurized ash agglomerating fluidized-bed coal gasification system: Topical report, Process analysis, FY 1983

    SciTech Connect

    1987-07-31

    KRW Energy Systems, Inc., is engaged in the continuing development of a pressurized, fluidized-bed gasification process at its Waltz Mill Site in Madison, Pennsylvania. The overall objective of the program is to demonstrate the viability of the KRW process for the environmentally-acceptable production of low- and medium-Btu fuel gas from a variety of fossilized carbonaceous feedstocks and industrial fuels. This report presents process analysis of the 24 ton-per-day Process Development Unit (PDU) operations and is a continuation of the process analysis work performed in 1980 and 1981. Included is work performed on PDU process data; gasification; char-ash separation; ash agglomeration; fines carryover, recycle, and consumption; deposit formation; materials; and environmental, health, and safety issues. 63 figs., 43 tabs.

  1. Neurobiological foundations of neurologic music therapy: rhythmic entrainment and the motor system

    PubMed Central

    Thaut, Michael H.; McIntosh, Gerald C.; Hoemberg, Volker

    2015-01-01

    Entrainment is defined by a temporal locking process in which one system’s motion or signal frequency entrains the frequency of another system. This process is a universal phenomenon that can be observed in physical (e.g., pendulum clocks) and biological systems (e.g., fire flies). However, entrainment can also be observed between human sensory and motor systems. The function of rhythmic entrainment in rehabilitative training and learning was established for the first time by Thaut and colleagues in several research studies in the early 1990s. It was shown that the inherent periodicity of auditory rhythmic patterns could entrain movement patterns in patients with movement disorders (see for a review: Thaut et al., 1999). Physiological, kinematic, and behavioral movement analysis showed very quickly that entrainment cues not only changed the timing of movement but also improved spatial and force parameters. Mathematical models have shown that anticipatory rhythmic templates as critical time constraints can result in the complete specification of the dynamics of a movement over the entire movement cycle, thereby optimizing motor planning and execution. Furthermore, temporal rhythmic entrainment has been successfully extended into applications in cognitive rehabilitation and speech and language rehabilitation, and thus become one of the major neurological mechanisms linking music and rhythm to brain rehabilitation. These findings provided a scientific basis for the development of neurologic music therapy. PMID:25774137

  2. Modified mass action law-based model to correlate the solubility of solids and liquids in entrained supercritical carbon dioxide.

    PubMed

    González, J C; Vieytes, M R; Botana, A M; Vieites, J M; Botana, L M

    2001-02-23

    The solubility of solids and liquids in supercritical CO2 with added entrainers was modeled with a modified version of the equation of Chrastil to include the effect of entrainers. By considering the formation of the solute-entrainer-solvent complexes an equation is obtained which predicts an exponential increase of solubility with fluid density and/or entrainer concentration. The correlating model was tested by non-linear regression through a computerized iterative process for several systems where an entrainer was present. Four experimental parameters are easily regressed from experimental data, hence the corresponding properties of components such as chemical potentials or critical parameters are not needed. Instead of its simplicity, this thermodynamical model provided a good correlation of the solubility enhancement in the presence of entrainer effect. PMID:11263564

  3. EEG oscillations entrain their phase to high-level features of speech sound.

    PubMed

    Zoefel, Benedikt; VanRullen, Rufin

    2016-01-01

    Phase entrainment of neural oscillations, the brain's adjustment to rhythmic stimulation, is a central component in recent theories of speech comprehension: the alignment between brain oscillations and speech sound improves speech intelligibility. However, phase entrainment to everyday speech sound could also be explained by oscillations passively following the low-level periodicities (e.g., in sound amplitude and spectral content) of auditory stimulation-and not by an adjustment to the speech rhythm per se. Recently, using novel speech/noise mixture stimuli, we have shown that behavioral performance can entrain to speech sound even when high-level features (including phonetic information) are not accompanied by fluctuations in sound amplitude and spectral content. In the present study, we report that neural phase entrainment might underlie our behavioral findings. We observed phase-locking between electroencephalogram (EEG) and speech sound in response not only to original (unprocessed) speech but also to our constructed "high-level" speech/noise mixture stimuli. Phase entrainment to original speech and speech/noise sound did not differ in the degree of entrainment, but rather in the actual phase difference between EEG signal and sound. Phase entrainment was not abolished when speech/noise stimuli were presented in reverse (which disrupts semantic processing), indicating that acoustic (rather than linguistic) high-level features play a major role in the observed neural entrainment. Our results provide further evidence for phase entrainment as a potential mechanism underlying speech processing and segmentation, and for the involvement of high-level processes in the adjustment to the rhythm of speech.

  4. Functionalization of polymer powders for SLS-processes using an atmospheric plasma jet in a fluidized bed reactor

    SciTech Connect

    Sachs, Marius; Schmitt, Adeliene; Schmidt, Jochen; Peukert, Wolfgang; Wirth, Karl-Ernst

    2015-05-22

    Recently additive manufacturing processes such as selective laser sintering (SLS) of polymers have gained more importance for industrial applications [1]. Tailor-made modification of polymers is essential in order to make these processes more efficient and to cover the industrial demands. The so far used polymer materials show weak performance regarding the mechanical stability of processed parts. To overcome this limitation, a new route to functionalize the surface of commercially available polymer particles (PA12; PE-HD; PP) using an atmospheric plasma jet in combination with a fluidized bed reactor has been investigated. Consequently, an improvement of adhesion and wettability [2] of the polymer surface without restraining the bulk properties of the powder is achieved. The atmospheric plasma jet process can provide reactive species at moderate temperatures which are suitable for polymer material. The functionalization of the polymer powders improves the quality of the devices build in a SLS-process.

  5. Analysis of the laser powder bed fusion additive manufacturing process through experimental measurement and finite element modeling

    NASA Astrophysics Data System (ADS)

    Dunbar, Alexander Jay

    The objective in this work is to provide rigourous experimental measurements to aid in the development of laser powder bed fusion (LPBF) additive manufacturing (AM). A specialized enclosed instrumented measurement system is designed to provide in situ experimental measurements of temperature and distortion. Experiments include comparisons of process parameters, materials and LPBF machines. In situ measurements of distortion and temperature made throughout the build process highlight inter-layer distortion effects previously undocumented for laser powder bed fusion. Results from these experiments are also be implemented in the development and validation of finite element models of the powder bed build process. Experimental analysis is extended from small-scale to larger part-scale builds where experimental post-build measurements are used in analysis of distortion profiles. Experimental results provided from this study are utilized in the validation of a finite element model capable of simulating production scale parts. The validated finite element model is then implemented in the analysis of the part to provide information regarding the distortion evolution process. A combination of experimental measurements and simulation results are used to identify the mechanism that results in the measured distortion profile for this geometry. Optimization of support structure primarily focuses on the minimization of material use and scan time, but no information regarding failure criteria for support structure is available. Tensile test samples of LPBF built support structure are designed, built, and tested to provide measurements of mechanical properties of the support structure. Experimental tests show that LPBF built support structure has only 30-40% of the ultimate tensile strength of solid material built in the same machine. Experimental measurement of LPBF built support structure provides clear failure criteria to be utilized in the future design and implementation of

  6. Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 1: Instability experiment

    NASA Technical Reports Server (NTRS)

    Shy, Shenqyang S.

    1990-01-01

    The existence and persistence of marine stratocumulus play a significant role in the overall energy budget of the earth. Their stability and entrainment process are important in global climate studies, as well as for local weather forecasting. The purposes of the experimental simulations are to study this process and to address this paradox. The effects of buoyancy reversal is investigated, followed by two types of experiments. An instability experiment involves the behavior of a fully turbulent wake near the inversion generated by a sliding plate. Due to buoyancy reversal, the heavy, mixed fluid starts to sink, turning the potential energy created by the mixing process into kinetic energy, thereby increasing the entrainment rate. An entrainment experiment, using a vertically oscillating grid driven by a controllable speed motor, produces many eddy-induced entrainments at a surface region on scales much less than the depth of the layer.

  7. Flow Dynamics and Sediment Entrainment in Natural Turbidity Currents Inferred from Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Traer, M. M.; Hilley, G. E.; Fildani, A.

    2009-12-01

    Submarine turbidity currents derive their momentum from gravity acting upon the density contrast between sediment-laden and clear water, and so unlike fluvial systems, the dynamics of such flows are inextricably linked to the rates at which they deposit and entrain sediment. We have analyzed the sensitivity of the growth and maintenance of turbidity currents to sediment entrainment and deposition using the layer-averaged equations of conservation of fluid and sediment mass, and conservation of momentum and turbulent kinetic energy. Our model results show that the dynamics of turbidity currents are extremely sensitive to the functional form and empirical constants of the relationship between sediment entrainment and friction velocity. Data on the relationship between sediment entrainment and friction velocity for submarine density flows are few and as a result, entrainment formulations are populated with data from sub-aerial flows not driven by the density contrast between clear and turbid water. If we entertain the possibility that sediment entrainment in sub-aerial rivers is different than in dense underflows, flow parameters such as velocity, height, and concentration were found nearly impossible to predict beyond a few hundred meters based on the limited laboratory data available that constrain the sediment entrainment process in turbidity currents. The sensitivity of flow dynamics to the functional relationship between friction velocity and sediment entrainment indicates that independent calibration of a sediment entrainment law in the submarine environment is necessary to realistically predict the dynamics of these flows and the resulting patterns of erosion and deposition. To calibrate such a relationship, we have developed an inverse methodology that utilizes existing submarine channel morphology as a means of constraining the sediment entrainment function parameters. We use a Bayesian Metropolis-Hastings sampler to determine the sediment entrainment

  8. Washing of the AN-107 entrained solids

    SciTech Connect

    GJ Lumetta; FV Hoopes

    2000-03-31

    This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing on the composition of the entrained solids in the diluted AN-107 low-activity waste (LAW) sample. The objective of this work was to gather data on the solubility of the AN-107 entrained solids in 0.01 M NaOH, so that BNFL can evaluate whether these solids require caustic leaching.

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

    SciTech Connect

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

    1995-02-01

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

  10. Soy protein recovery in a solvent-free process using continuous liquid-solid circulating fluidized bed ion exchanger.

    PubMed

    Prince, Andrew; Bassi, Amarjeet S; Haas, Christine; Zhu, Jesse X; Dawe, Jennifer

    2012-01-01

    Soy protein concentrates and soy protein isolates act as ingredients in bakery, meat and dairy products, baby formulas, starting materials for spun textured vegetable products, and other nutritional supplements. In this study, the effectiveness of a liquid-solid circulating fluidized bed (LSCFB) ion exchanger is demonstrated for the recovery of soluble soy proteins from full fat and defatted soy flour. Under steady-state operating conditions, about 50% of the proteins could be recovered from the feed streams entering the ion exchanger. The LSCFB was shown to be a promising system for the recovery of soy protein from both defatted and full fat soy flour solutions. As the ion exchange process captures dissolved proteins, the system may offer a less damaging form of processing compared with the acid precipitation process where soy protein aggregates form and functionality is affected. In addition, the LSCFB allows simultaneous adsorption and desorption of the proteins allowing for a continuous operation. No prefiltration of feed containing suspended particles is required as well, because fluidization is used in place of packed bed technology to improve on current ion exchange processes. PMID:22002948

  11. Mathematical modeling of slope flows with entrainment as flows of non-Newtonian fluids

    NASA Astrophysics Data System (ADS)

    Zayko, Julia; Eglit, Margarita

    2015-04-01

    Non-Newtonian fluids in which the shear stresses are nonlinear functions of the shear strain rates are used to model slope flows such as snow avalanches, mudflows, debris flows. The entrainment of bottom material is included into the model basing on the assumption that in entraining flows the bed friction is equal to the shear stress of the bottom material (Issler et al, 2011). Unsteady motion down long homogeneous slopes with constant inclines is studied numerically for different flow rheologies and different slope angles. Variation of the velocity profile, increase of the flow depth and velocity due to entrainment as well as the value of the entrainment rate is calculated. Asymptotic formulae for the entrainment rate are derived for unsteady flows of different rheological properties. REFERENCES Chowdhury M., Testik F., 2011. Laboratory testing of mathematical models for high-concentration fluid mud turbidity currents. Ocean Engineering 38, 256-270. Eglit, M.E., Demidov, K.S., 2005. Mathematical modeling of snow entrainment in avalanche motion. Cold Reg. Sci. Technol. 43 (1-2), 10-23. Eglit M. E., Yakubenko A. E., 2012, Mathematical Modeling of slope flows entraining bottom material. Eglit M. E., Yakubenko A. E., 2014, Numerical modeling of slope flows entraining bottom material. Cold Reg. Sci. Technol. 108, 139-148. Issler D, M. Pastor Peréz. 2011. Interplay of entrainment and rheology in snow avalanches; a numerical study. Annals of Glaciology, 52(58), pp.143-147 Kern M. A., Tiefenbacher F., McElwaine J., N., 2004. The rheology of snow in large chute flows. Cold Regions Science and Technology, 39, 181 -192. Naaim, M., Faug, T., Naaim-Bouvet, F., 2003. Dry granular flow modelling including erosion and deposition. Surv. Geophys. 24, 569-585. Naaim, M., Naaim-Bouvet, F., Faug, T., Bouchet, A., 2004. Dense snow avalanche modeling: flow, erosion, deposition and obstacle effects. Cold Reg. Sci. Technol. 39, 193-204. Rougier, J & Kern, M 2010, 'Predicting snow

  12. Coupling governs entrainment range of circadian clocks

    PubMed Central

    Abraham, Ute; Granada, Adrián E; Westermark, Pål O; Heine, Markus; Kramer, Achim; Herzel, Hanspeter

    2010-01-01

    Circadian clocks are endogenous oscillators driving daily rhythms in physiology and behavior. Synchronization of these timers to environmental light–dark cycles (‘entrainment') is crucial for an organism's fitness. Little is known about which oscillator qualities determine entrainment, i.e., entrainment range, phase and amplitude. In a systematic theoretical and experimental study, we uncovered these qualities for circadian oscillators in the suprachiasmatic nucleus (SCN—the master clock in mammals) and the lung (a peripheral clock): (i) the ratio between stimulus (zeitgeber) strength and oscillator amplitude and (ii) the rigidity of the oscillatory system (relaxation rate upon perturbation) determine entrainment properties. Coupling among oscillators affects both qualities resulting in increased amplitude and rigidity. These principles explain our experimental findings that lung clocks entrain to extreme zeitgeber cycles, whereas SCN clocks do not. We confirmed our theoretical predictions by showing that pharmacological inhibition of coupling in the SCN leads to larger ranges of entrainment. These differences between master and the peripheral clocks suggest that coupling-induced rigidity in the SCN filters environmental noise to create a robust circadian system. PMID:21119632

  13. Tuning the phase of circadian entrainment

    PubMed Central

    Bordyugov, Grigory; Abraham, Ute; Granada, Adrian; Rose, Pia; Imkeller, Katharina; Kramer, Achim; Herzel, Hanspeter

    2015-01-01

    The circadian clock coordinates daily physiological, metabolic and behavioural rhythms. These endogenous oscillations are synchronized with external cues (‘zeitgebers’), such as daily light and temperature cycles. When the circadian clock is entrained by a zeitgeber, the phase difference ψ between the phase of a clock-controlled rhythm and the phase of the zeitgeber is of fundamental importance for the fitness of the organism. The phase of entrainment ψ depends on the mismatch between the intrinsic period τ and the zeitgeber period T and on the ratio of the zeitgeber strength to oscillator amplitude. Motivated by the intriguing complexity of empirical data and by our own experiments on temperature entrainment of mouse suprachiasmatic nucleus (SCN) slices, we present a theory on how clock and zeitgeber properties determine the phase of entrainment. The wide applicability of the theory is demonstrated using mathematical models of different complexity as well as by experimental data. Predictions of the theory are confirmed by published data on Neurospora crassa strains for different period mismatches τ − T and varying photoperiods. We apply a novel regression technique to analyse entrainment of SCN slices by temperature cycles. We find that mathematical models can explain not only the stable asymptotic phase of entrainment, but also transient phase dynamics. Our theory provides the potential to explore seasonal variations of circadian rhythms, jet lag and shift work in forthcoming studies. PMID:26136227

  14. Informational Constraints on Spontaneous Visuomotor Entrainment

    PubMed Central

    Varlet, Manuel; Bucci, Colleen; Richardson, Michael J.; Schmidt, R. C.

    2015-01-01

    Past research has revealed that an individual's rhythmic limb movements become spontaneously entrained to an environmental rhythm if visual information about the rhythm is available and its frequency is near that of the individual's movements. Research has also demonstrated that if the eyes track an environmental stimulus, the spontaneous entrainment to the rhythm is strengthened. One hypothesis explaining this enhancement of spontaneous entrainment is that the limb movements and eye movements are linked through a neuromuscular coupling or synergy. Another is that eye-tracking facilitates the pick up of important coordinating information. Experiment 1 investigated the first hypothesis by evaluating whether any rhythmic movement of the eyes would facilitate spontaneous entrainment. Experiment 2 and 3 (respectively) explored whether eye-tracking strengthens spontaneous entrainment by allowing the pickup of trajectory direction change information or allowing an increase in the amount of information to be picked-up. Results suggest that the eye-tracking enhancement of spontaneous entrainment is a consequence of increasing the amount of information available to be picked-up. PMID:25866944

  15. Multi-stage circulating fluidized bed syngas cooling

    DOEpatents

    Liu, Guohai; Vimalchand, Pannalal; Guan, Xiaofeng; Peng, WanWang

    2016-10-11

    A method and apparatus for cooling hot gas streams in the temperature range 800.degree. C. to 1600.degree. C. using multi-stage circulating fluid bed (CFB) coolers is disclosed. The invention relates to cooling the hot syngas from coal gasifiers in which the hot syngas entrains substances that foul, erode and corrode heat transfer surfaces upon contact in conventional coolers. The hot syngas is cooled by extracting and indirectly transferring heat to heat transfer surfaces with circulating inert solid particles in CFB syngas coolers. The CFB syngas coolers are staged to facilitate generation of steam at multiple conditions and hot boiler feed water that are necessary for power generation in an IGCC process. The multi-stage syngas cooler can include internally circulating fluid bed coolers, externally circulating fluid bed coolers and hybrid coolers that incorporate features of both internally and externally circulating fluid bed coolers. Higher process efficiencies can be realized as the invention can handle hot syngas from various types of gasifiers without the need for a less efficient precooling step.

  16. Scheduled daily exercise or feeding alters the phase of photic entrainment in Syrian hamsters.

    PubMed

    Mistlberger, R E

    1991-12-01

    Single daily bouts of appropriately timed activity can phase-shift or entrain circadian rhythms in rodents maintained in constant dark (DD). Whether this apparent feedback of behavioral activity to the circadian pacemaker has any adaptive significance in nuclear; circadian rhythms are normally entrained by light-dark (LD) cycles, and this may override any effects of activity. To address this issue, the phase of entrainment to LD cycles was examined in hamsters exposed to a daily exercise schedule (3 h of induced wheel running). Hamsters exercised late in the dark showed a significant delay of entrained phase in LD (i.e., they became relative "night owls") and lengthening of free-running periodicity in DD, compared to controls and hamsters exercised in midlight. Hamsters fed in midlight (arousal without wheel running) showed a significant advance of LD entrained phase (i.e., they became "early birds"). These observations provide the necessary rationale for further examination of the functional significance of behavioral feedback for the normal entrainment process. In addition, they rise the possibility that the entrained phase of human circadian rhythms can be similarly manipulated by behavioral procedures such as timed exercise.

  17. Lignite air-steam gasification in the fluidized bed of iron-containing slag catalysts

    SciTech Connect

    Kuznetsov, B.N.; Shchipko, M.L.; Golovin, Yu.

    1995-12-01

    The influence of fluidized bed of iron-containing slag particles on air-steam gasification of powdered Kansk-Achinsk lignite in entrained flow was studied in pilot installation with productivity about 60 kg per hour. Slag of Martin process and boiler slag were used as catalytic active materials until their complete mechanical attrition. Two following methods of catalytic gasification of lignite were compared: the partial gasification in stationary fluidized bed of slag particles with degree of fuel conversion 40-70% and complete gasification in circulating bed of slag particles. In the first case only the most reactive part of fuel is gasified with the simultaneously formation of porous carbon residue with good sorption ability. It was found the catalytic fluidized bed improves heat transfer from combustion to reduction zone of gas-generator and increases the rate of fuel conversion at the temperature range 900-1000{degrees}C. At these temperatures the degree of conversion is depended considerably on the duration time of fuel particles in the catalytic fluidized bed. The influence of catalytic fluidized bed height and velocity of reaction mixture on the temperature profiles in the gas-generator was studied. The optimal relationship was found between the fluidized bed height and velocity of flow which makes possible to produce the gas with higher calorific value at maximum degree of fuel conversion.

  18. Music and emotions: from enchantment to entrainment.

    PubMed

    Vuilleumier, Patrik; Trost, Wiebke

    2015-03-01

    Producing and perceiving music engage a wide range of sensorimotor, cognitive, and emotional processes. Emotions are a central feature of the enjoyment of music, with a large variety of affective states consistently reported by people while listening to music. However, besides joy or sadness, music often elicits feelings of wonder, nostalgia, or tenderness, which do not correspond to emotion categories typically studied in neuroscience and whose neural substrates remain largely unknown. Here we review the similarities and differences in the neural substrates underlying these "complex" music-evoked emotions relative to other more "basic" emotional experiences. We suggest that these emotions emerge through a combination of activation in emotional and motivational brain systems (e.g., including reward pathways) that confer its valence to music, with activation in several other areas outside emotional systems, including motor, attention, or memory-related regions. We then discuss the neural substrates underlying the entrainment of cognitive and motor processes by music and their relation to affective experience. These effects have important implications for the potential therapeutic use of music in neurological or psychiatric diseases, particularly those associated with motor, attention, or affective disturbances. PMID:25773637

  19. Music and emotions: from enchantment to entrainment.

    PubMed

    Vuilleumier, Patrik; Trost, Wiebke

    2015-03-01

    Producing and perceiving music engage a wide range of sensorimotor, cognitive, and emotional processes. Emotions are a central feature of the enjoyment of music, with a large variety of affective states consistently reported by people while listening to music. However, besides joy or sadness, music often elicits feelings of wonder, nostalgia, or tenderness, which do not correspond to emotion categories typically studied in neuroscience and whose neural substrates remain largely unknown. Here we review the similarities and differences in the neural substrates underlying these "complex" music-evoked emotions relative to other more "basic" emotional experiences. We suggest that these emotions emerge through a combination of activation in emotional and motivational brain systems (e.g., including reward pathways) that confer its valence to music, with activation in several other areas outside emotional systems, including motor, attention, or memory-related regions. We then discuss the neural substrates underlying the entrainment of cognitive and motor processes by music and their relation to affective experience. These effects have important implications for the potential therapeutic use of music in neurological or psychiatric diseases, particularly those associated with motor, attention, or affective disturbances.

  20. Altered streamflow and sediment entrainment in the Gunnison Gorge

    USGS Publications Warehouse

    Elliott, J.G.; Parker, R.S.

    1997-01-01

    The Gunnison River in the Gunnison Gorge is a canyon river where upstream dams regulate mainstem discharge but do not affect debris-flow sediment supply from tributaries entering below the reservoirs. Regulation since 1966 has altered flood frequency, streambed mobility, and fluvial geomorphology creating potential resource-management issues. The duration of moderate streamflows between 32.3 and 85.0 m3/s has increased threefold since 1966. This, along with flood-peak attenuation, has facilitated fine-sediment deposition and vegetation encroachment on stream banks. The Shields equation and on-site channel geometry and bed-material measurements were used to assess changes in sediment entrainment in four alluvial reaches. Sand and fine gravel are transported through riffle/pool reaches at most discharges, but the cobbles and boulders composing the streambed in many reaches now are infrequently entrained. Periodic debris flows add coarse sediment to rapids and can increase pool elevation and the streambed area affected by backwater and fine-sediment accumulation. Debris-flow supplied boulders accumulate on fans and in rapids and constrict the channel until reworked by larger floods. The response to streamflow-regime changes in the Gunnison Gorge could serve as an analog for alluvial reaches in other regulated canyon rivers.

  1. Observation and simulation of heterogeneous 2D water and solute flow processes in ditch beds for subsequent catchment modelling

    NASA Astrophysics Data System (ADS)

    Dages, Cecile; Samouelian, Anatja; Lanoix, Marthe; Dollinger, Jeanne; Chakkour, Sara; Chovelon, Gabrielle; Trabelsi, Khouloud; Voltz, Marc

    2015-04-01

    Ditches are involved in the transfer of pesticide to surface and groundwaters (e.g. Louchart et al., 2001). Soil horizons underlying ditch beds may present specific soil characteristics compared to neighbouring field soils due to erosion/deposition processes, to the specific biological activities (rooting dynamic and animal habitat) in the ditches (e.g. Vaughan et al., 2008) and to management practices (burning, dredging, mowing,...). Moreover, in contrast to percolation processes in field soils that can be assumed to be mainly 1D vertical, those occurring in the ditch beds are by essence 2D or even 3D. Nevertheless, due to a lake of knowledge, these specific aspects of transfer within ditch beds are generally omitted for hydrological simulation at the catchment scale (Mottes et al., 2014). Accordingly, the aims of this study were i) to characterize subsurface solute transfer through ditch beds and ii) to determine equivalent hydraulic parameters of the ditch beds for use in catchment scale hydrological simulations. A complementary aim was to evaluate the error in predictions performed when percolation in ditches is assumed to be similar to that in the neighbouring field soil. First, bromide transfer experiments were performed on undisturbed soil column (15 cm long with a 15 cm inner-diameter), horizontally and vertically sampled within each soil horizon underlying a ditch bed and within the neighboring field. Columns were sampled at the Roujan catchment (Hérault, France), which belongs to the long term Mediterranean hydrological observatory OMERE (Voltz and Albergel, 2002). Second, for each column, a set of parameters was determined by inverse optimization with mobile-immobile or dual permeability models, with CXTFIT (Toride et al., 1999) or with HYDRUS (Simunek et al., 1998). Third, infiltration and percolation in the ditch was simulated by a 2D flow domain approach considering the 2D variation in hydraulic properties of the cross section of a ditch bed. Last

  2. Assessment Approach for Identifying Compatibility of Restoration Projects with Geomorphic and Flooding Processes in Gravel Bed Rivers.

    PubMed

    DeVries, Paul; Aldrich, Robert

    2015-08-01

    A critical requirement for a successful river restoration project in a dynamic gravel bed river is that it be compatible with natural hydraulic and sediment transport processes operating at the reach scale. The potential for failure is greater at locations where the influence of natural processes is inconsistent with intended project function and performance. We present an approach using practical GIS, hydrologic, hydraulic, and sediment transport analyses to identify locations where specific restoration project types have the greatest likelihood of working as intended because their function and design are matched with flooding and morphologic processes. The key premise is to identify whether a specific river analysis segment (length ~1-10 bankfull widths) within a longer reach is geomorphically active or inactive in the context of vertical and lateral stabilities, and hydrologically active for floodplain connectivity. Analyses involve empirical channel geometry relations, aerial photographic time series, LiDAR data, HEC-RAS hydraulic modeling, and a time-integrated sediment transport budget to evaluate trapping efficiency within each segment. The analysis segments are defined by HEC-RAS model cross sections. The results have been used effectively to identify feasible projects in a variety of alluvial gravel bed river reaches with lengths between 11 and 80 km and 2-year flood magnitudes between ~350 and 1330 m(3)/s. Projects constructed based on the results have all performed as planned. In addition, the results provide key criteria for formulating erosion and flood management plans. PMID:25910870

  3. Assessment Approach for Identifying Compatibility of Restoration Projects with Geomorphic and Flooding Processes in Gravel Bed Rivers.

    PubMed

    DeVries, Paul; Aldrich, Robert

    2015-08-01

    A critical requirement for a successful river restoration project in a dynamic gravel bed river is that it be compatible with natural hydraulic and sediment transport processes operating at the reach scale. The potential for failure is greater at locations where the influence of natural processes is inconsistent with intended project function and performance. We present an approach using practical GIS, hydrologic, hydraulic, and sediment transport analyses to identify locations where specific restoration project types have the greatest likelihood of working as intended because their function and design are matched with flooding and morphologic processes. The key premise is to identify whether a specific river analysis segment (length ~1-10 bankfull widths) within a longer reach is geomorphically active or inactive in the context of vertical and lateral stabilities, and hydrologically active for floodplain connectivity. Analyses involve empirical channel geometry relations, aerial photographic time series, LiDAR data, HEC-RAS hydraulic modeling, and a time-integrated sediment transport budget to evaluate trapping efficiency within each segment. The analysis segments are defined by HEC-RAS model cross sections. The results have been used effectively to identify feasible projects in a variety of alluvial gravel bed river reaches with lengths between 11 and 80 km and 2-year flood magnitudes between ~350 and 1330 m(3)/s. Projects constructed based on the results have all performed as planned. In addition, the results provide key criteria for formulating erosion and flood management plans.

  4. Experimental Investigation of Entrainment Rate by Debris Flows: from Shear Stress to Granular Temperature

    NASA Astrophysics Data System (ADS)

    Hill, K. M.; Longjas, A.; Moberly, D.

    2015-12-01

    Debris flows - flows of boulders, gravel, sand, fine particles, and fluids - erode sediment from steep hillsides and deposit them at lower slopes. Current model frameworks for erosion by debris flow vary significantly and include those that consider macroscopic fields such as excess shear stresses, similar to traditional models of bedload transport, to those that consider the "granular" physics, from force chains (related to bed fabric) to granular temperatures (related to random kinetic energy of the flow). We perform experiments to investigate the underlying mechanics associated with entrainment of bed materials by overlying flows in an instrumented laboratory debris flow flume. In particular, we investigate how the erosion rate of a flowing mass impinging on an erodible bed of particles depends on boundary conditions, dynamics of the flow, and the state of the bed. Using high speed imaging to capture average and instantaneous particle dynamics simultaneously with bed stress measurements, we investigate the effectiveness of a variety of model frameworks for capturing the relationships between flow dynamics and erosion rates. We find no correlation between the bed shear stress associated with the mass of the flow and erosion rate. Similarly, we found no correlation between the erosion rate and a Reynolds stress, that is, the stress associated with correlations between downstream and vertical velocity fluctuations. On the other hand, we found that granular temperature is well-correlated with entrainment rate during particular phases of our experimental debris flow. In particular, we found the instantaneous entrainment rate ɛ is linearly dependent on the ratio of the granular temperature Tg to the kinetic energy associated with the average flow velocity u: ɛ ~ (Tg / ρm u2) where ρm is the local instantaneous density of the flow. We present these results and discuss how they vary with the state of the flow, boundary conditions, and particle mixtures.

  5. Fluidized-bed combustion process evaluation and program support. Annual report, October 1979-September 1980

    SciTech Connect

    Johnson, I.; Podolski, W.F.; Swift, W.M.; Carls, E.L.; Helt, J.E.; Henry, R.F.; Herzenberg, C.L.; Hanway, J.E.; Griggs, K.E.

    1981-03-01

    The purpose of this program is to support the pressurized fluidized-bed combustion project management team at Morgantown Energy Technology Center by providing a core group of experienced personnel (1) to prepare (a) program interaction plans suitable for recommending program needs and (b) recommendations for the DOE-PFBC development program, (2) to analyze data and designs for two large pilot-scale PFBC programs (i.e., Curtiss-Wright and IEA Grimethorpe), and (3) to participate in design/review for the large PFBC programs. Results are reported on a development methodology for the commercialization of PFBC technology, a FBC instrumentation state-of-the-art review, the development of a sodium sulfate dew point measurement instrument, and the evaluation of cyclones for hot gas cleanup.

  6. Pedogenic slickensides, indicators of strain and deformation processes in red bed sequences of the Appalachian foreland

    SciTech Connect

    Gray, M.B. ); Nickelsen, R.P. )

    1989-01-01

    Pedogenic slickensides are convex-concave slip surfaces that form during expansion/contraction in expansive clay soils such as Vertisols. In the central Appalachians, they occur near the tops of fining-upward cycles in Paleozoic red beds such as the Bloomsburg, Catskill, and Mauch Chunk Formations. Pedogenic slickensides are found in association with other pedogenic (or paleosol) features such as clay-skinned peds, in situ calcareous nodules, and root impressions. Repeated movements along these shear planes during pedogenesis produce strongly aligned clay particles adjacent to pedogenic slickensides; as a result, they are preserved as discrete fractures throughout diagenesis, compaction, and superimposed tectonic deformation. During whole-rock deformation, pedogenic slickensides segregate penetratively deformed rocks into independent, foliate packets and serve as discontinuities that are followed by later structural features. Because the original morphology of pedogenic slickensides is known, they can be used as crude strain markers.

  7. Processing RoxAnn sonar data to improve its categorization of lake bed surficial sediments

    USGS Publications Warehouse

    Cholwek, Gary; Bonde, John; Li, Xing; Richards, Carl; Yin, Karen

    2000-01-01

    To categorize spawning and nursery habitat for lake trout in Minnesota's near shore waters of Lake Superior, data was collected with a single beam echo sounder coupled with a RoxAnn bottom classification sensor. Test areas representative of different bottom surficial substrates were sampled. The collected data consisted of acoustic signals which showed both depth and substrate type. The location of the signals was tagged in real-time with a DGPS. All data was imported into a GIS database. To better interpret the output signal from the RoxAnn, several pattern classifiers were developed by multivariate statistical method. From the data a detailed and accurate map of lake bed bathymetry and surficial substrate types was produced. This map will be of great value to fishery and other natural resource managers.

  8. Factors affecting the geochemistry of a thick, subbituminous coal bed in the Powder River Basin: volcanic, detrital, and peat-forming processes

    USGS Publications Warehouse

    Crowley, S.S.; Ruppert, L.F.; Belkin, H.E.; Stanton, R.W.; Moore, T.A.

    1993-01-01

    .provides further support for a volcanic ash component. Other factors that probably affected the geochemistry of the coal bed include (1) detrital input associated with the deposition of the roof rocks of the coal bed, (2) peat-forming processes and plant material, and (3) epigenetic ground-water flow. ?? 1993.

  9. Application of a combined process of moving-bed biofilm reactor (MBBR) and chemical coagulation for dyeing wastewater treatment.

    PubMed

    Shin, D H; Shin, W S; Kim, Y H; Han, Myung Ho; Choi, S J

    2006-01-01

    A combined process consisted of a Moving-Bed Biofilm Reactor (MBBR) and chemical coagulation was investigated for textile wastewater treatment. The pilot scale MBBR system is composed of three MBBRs (anaerobic, aerobic-1 and aerobic-2 in series), each reactor was filled with 20% (v/v) of polyurethane-activated carbon (PU-AC) carrier for biological treatment followed by chemical coagulation with FeCl2. ln the MBBR process, 85% of COD and 70% of color (influent COD = 807.5 mg/L and color = 3,400 PtCo unit) were removed using relatively low MLSS concentration and short hydraulic retention time (HRT = 44 hr). The biologically treated dyeing wastewater was subjected to chemical coagulation. After coagulation with FeCl2, 95% of COD and 97% of color were removed overall. The combined process of MBBR and chemical coagulation has promising potential for dyeing wastewater treatment. PMID:17163056

  10. Treatment of gas industry wastes using the biological granular activated carbon fluidized bed reactor process. Annual report, August 1994

    SciTech Connect

    Hickey, R.; Wagner, D.; Sunday, A.; Heine, B.; Rajan, R.

    1994-08-01

    The Granular Activated Carbon-Fluidized Bed Reactor (GAC-FBR) system is a high rate process that combines the advantages of biological and physical-chemical treatment in a single unit operation. The process is particularly well-suited to treatment of contaminants present in water and wastewater at relatively low concentrations. Process economics indicate the GAC-FBR can be extremely cost-effective compared to aqueous phase GAC adsorption and air stripping followed by vapor phase control. Accordingly, three field trials are scheduled for the next 18 months; one at a manufactured gas plant site (PAHs), one at a gas dehydration site (BTEX), and one to treat a chlorinated solvent (TCE) at a government installation.

  11. Speech entrainment compensates for Broca's area damage.

    PubMed

    Fridriksson, Julius; Basilakos, Alexandra; Hickok, Gregory; Bonilha, Leonardo; Rorden, Chris

    2015-08-01

    Speech entrainment (SE), the online mimicking of an audiovisual speech model, has been shown to increase speech fluency in patients with Broca's aphasia. However, not all individuals with aphasia benefit from SE. The purpose of this study was to identify patterns of cortical damage that predict a positive response SE's fluency-inducing effects. Forty-four chronic patients with left hemisphere stroke (15 female) were included in this study. Participants completed two tasks: 1) spontaneous speech production, and 2) audiovisual SE. Number of different words per minute was calculated as a speech output measure for each task, with the difference between SE and spontaneous speech conditions yielding a measure of fluency improvement. Voxel-wise lesion-symptom mapping (VLSM) was used to relate the number of different words per minute for spontaneous speech, SE, and SE-related improvement to patterns of brain damage in order to predict lesion locations associated with the fluency-inducing response to SE. Individuals with Broca's aphasia demonstrated a significant increase in different words per minute during SE versus spontaneous speech. A similar pattern of improvement was not seen in patients with other types of aphasia. VLSM analysis revealed damage to the inferior frontal gyrus predicted this response. Results suggest that SE exerts its fluency-inducing effects by providing a surrogate target for speech production via internal monitoring processes. Clinically, these results add further support for the use of SE to improve speech production and may help select patients for SE treatment. PMID:25989443

  12. Speech entrainment compensates for Broca's area damage.

    PubMed

    Fridriksson, Julius; Basilakos, Alexandra; Hickok, Gregory; Bonilha, Leonardo; Rorden, Chris

    2015-08-01

    Speech entrainment (SE), the online mimicking of an audiovisual speech model, has been shown to increase speech fluency in patients with Broca's aphasia. However, not all individuals with aphasia benefit from SE. The purpose of this study was to identify patterns of cortical damage that predict a positive response SE's fluency-inducing effects. Forty-four chronic patients with left hemisphere stroke (15 female) were included in this study. Participants completed two tasks: 1) spontaneous speech production, and 2) audiovisual SE. Number of different words per minute was calculated as a speech output measure for each task, with the difference between SE and spontaneous speech conditions yielding a measure of fluency improvement. Voxel-wise lesion-symptom mapping (VLSM) was used to relate the number of different words per minute for spontaneous speech, SE, and SE-related improvement to patterns of brain damage in order to predict lesion locations associated with the fluency-inducing response to SE. Individuals with Broca's aphasia demonstrated a significant increase in different words per minute during SE versus spontaneous speech. A similar pattern of improvement was not seen in patients with other types of aphasia. VLSM analysis revealed damage to the inferior frontal gyrus predicted this response. Results suggest that SE exerts its fluency-inducing effects by providing a surrogate target for speech production via internal monitoring processes. Clinically, these results add further support for the use of SE to improve speech production and may help select patients for SE treatment.

  13. Direct process integration of cell disruption and fluidised bed adsorption in the recovery of labile microbial enzymes.

    PubMed

    Bierau, H; Hinton, R J; Lyddiatt, A

    2001-01-01

    The practical feasibility and generic applicability of the direct integration of cell disruption by bead milling with the capture of intracellular products by fluidised bed adsorption has been demonstrated. Pilot-scale purification of the enzyme L-asparaginase from unclarified Erwinia chrysanthemi disruptates exploiting this novel approach yielded an interim product which rivalled or bettered that produced by the current commercial process employing discrete operations of alkaline lysis, centrifugal clarification and batch adsorption. In addition to improved yield and quality of product, the process time during primary stages of purification was greatly diminished. Two cation exchange adsorbents, CM HyperD LS (Biosepra/Life Technologies) and SP UpFront (custom made SP form of a prototype stainless steel/agarose matrix, UpFront Chromatography) were physically and biochemically evaluated for such direct product sequestration. Differences in performance with regard to product capacity and adsorption/desorption kinetics were demonstrated and are discussed with respect to the design of adsorbents for specific applications. In any purification of L-asparaginase (pI = 8.6), product-debris interactions commonly diminish the recovery of available product. It was demonstrated herein, that immediate disruptate exposure to a fluidised bed adsorbent promoted concomitant reduction of product in the liquid phase, which clearly counter-acted the product-debris interactions to the benefit of product yield.

  14. Column flooding and entrainment. [Estimation of maximum allowable vapor velocity and entrainment in a distillation column

    SciTech Connect

    Lygeros, A.I.; Magoulas, K.G.

    1986-12-01

    Here is a way to estimate maximum allowable vapor velocity and entrainment in a distillation column. The method can easily be computerized. It is based on equations derived from the widely accepted correlations. The equation for flooding velocity is applicable to bubble-cup, sieve and valve trays, while the entrainment equation applies only to sieve trays.

  15. Processes for washing a spent ion exchange bed and for treating biomass-derived pyrolysis oil, and apparatuses for treating biomass-derived pyrolysis oil

    SciTech Connect

    Baird, Lance Awender; Brandvold, Timothy A.

    2015-11-24

    Processes and apparatuses for washing a spent ion exchange bed and for treating biomass-derived pyrolysis oil are provided herein. An exemplary process for washing a spent ion exchange bed employed in purification of biomass-derived pyrolysis oil includes the step of providing a ion-depleted pyrolysis oil stream having an original oxygen content. The ion-depleted pyrolysis oil stream is partially hydrotreated to reduce the oxygen content thereof, thereby producing a partially hydrotreated pyrolysis oil stream having a residual oxygen content that is less than the original oxygen content. At least a portion of the partially hydrotreated pyrolysis oil stream is passed through the spent ion exchange bed. Water is passed through the spent ion exchange bed after passing at least the portion of the partially hydrotreated pyrolysis oil stream therethrough.

  16. Kinematics of flow and sediment particles at entrainment and deposition

    NASA Astrophysics Data System (ADS)

    Antico, Federica; Sanches, Pedro; Aleixo, Rui; Ferreira, Rui M. L.

    2015-04-01

    A cohesionless granular bed subjected to a turbulent open-channel flow is analysed. The key objective is to clarify the kinematics of entrainment and deposition of individual sediment particles. In particular, we quantify a) the turbulent flow field in the vicinity of particles at the instants of their entrainment and of their deposition; b) the initial particle velocity and the particle velocity immediately before returning to rest. The experimental work was performed at the Hydraulics Laboratory of IST-UL in a 12.5 m long, 0.405 m wide glass-walled flume recirculating water and sediment through independent circuits. The granular bed was a 4.0 m long and 2.5 cm deep reach filled with 5 mm diameter glass beads packed (with some vibration) to a void fraction of 0.356, typical of random packing. Upstream the mobile bed reach the bed was composed of glued particles to ensure the development of a boundary layer with the same roughness. Laboratory tests were run under conditions of weak beadload transport with Shields parameters in the range 0.007 to 0.03. Froude numbers ranged from 0.63 to 0.95 while boundary Reynolds numbers were in the range 130 to 300. It was observed that the bed featured patches of regular arrangements: face centered cubic (fcc) or hexagonal close packing (hcp) blocks alternate with and body centered cubic (bcc) blocks. The resulting bed surface exhibits cleavage lines between blocks and there are spatial variations of bed elevation. The option for artificial sediment allowed for a simplified description of particle positioning at the instant of entrainment. In particular support and pivoting angles are found analytically. Skin friction angles were determind experimentally. The only relevant variables are exposure (defined as the ratio of the actual frontal projection of the exposed area to the area of a circle with 5 mm diameter) and protrusion (defined as the vertical distance between the apex of the particle and the mean local bed elevation

  17. GC/MS characterization of condensable tars in the output stream of a stirred fixed-bed gasifier

    SciTech Connect

    Lamey, S.C.; McCaskill, K.B.; Smith, R.R.

    1981-12-01

    The output stream of the stirred fixed-bed gasifier at the Morgantown Energy Technology Center was sampled for total entrained material. A major portion of the entrained material, in addition to particles, is condensable tar that is subsequently removed from the process gas by wet scrubbing. Characterization of the entrained materials, specifically the tar, is important to establish contaminant levels and to evaluate performance of downstream cleanup units. Samples of tars were collected from the process unit in a combined ice, dry ice, and liquid nitrogen sampler and stored in a refrigerator. The tar samples were then separated into asphaltene, neutral oil, tar acid, and base fractions by solvent extraction using toluene, pentane, sulfuric acid, and potassium hydroxide extraction. Characterization of the fractions obtained from these tars include IR, UV, GC, and GC/MS analysis. The mass spectrometer analysis of the various isolates shows that many individual peaks in the gas chromatograph are in fact mixtures that can be readily identified by the mass spectrometer. It was found that many of the species identified in these fractions were members of aromatic homologous series consisting of parent, mono, di, and tri substituted compounds. Compound identification was made by comparison of the data system library and standard reference spectra. This paper will discuss the instrumental approach and limitation of the GC/MS and the results of the characterization studies of entrained hydrocarbons collected from the gasifier stream.

  18. Nonphotic entrainment of the human circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Klerman, E. B.; Rimmer, D. W.; Dijk, D. J.; Kronauer, R. E.; Rizzo, J. F. 3rd; Czeisler, C. A.

    1998-01-01

    In organisms as diverse as single-celled algae and humans, light is the primary stimulus mediating entrainment of the circadian biological clock. Reports that some totally blind individuals appear entrained to the 24-h day have suggested that nonphotic stimuli may also be effective circadian synchronizers in humans, although the nonphotic stimuli are probably comparatively weak synchronizers, because the circadian rhythms of many totally blind individuals "free run" even when they maintain a 24-h activity-rest schedule. To investigate entrainment by nonphotic synchronizers, we studied the endogenous circadian melatonin and core body temperature rhythms of 15 totally blind subjects who lacked conscious light perception and exhibited no suppression of plasma melatonin in response to ocular bright-light exposure. Nine of these fifteen blind individuals were able to maintain synchronization to the 24-h day, albeit often at an atypical phase angle of entrainment. Nonphotic stimuli also synchronized the endogenous circadian rhythms of a totally blind individual to a non-24-h schedule while living in constant near darkness. We conclude that nonphotic stimuli can entrain the human circadian pacemaker in some individuals lacking ocular circadian photoreception.

  19. On dust entrainment in photoevaporative winds

    NASA Astrophysics Data System (ADS)

    Hutchison, Mark A.; Price, Daniel J.; Laibe, Guillaume; Maddison, Sarah T.

    2016-09-01

    We investigate dust entrainment by photoevaporative winds in protoplanetary discs using dusty smoothed particle hydrodynamics. We use unequal-mass particles to resolve more than five orders of magnitude in disc/outflow density and a one-fluid formulation to efficiently simulate an equivalent magnitude range in drag stopping time. We find that only micron-sized dust grains and smaller can be entrained in extreme-UV radiation-driven winds. The maximum grain size is set by dust settling in the disc rather than aerodynamic drag in the wind. More generally, there is a linear relationship between the base flow density and the maximum entrainable grain size in the wind. A pileup of micron-sized dust grains can occur in the upper atmosphere at critical radii in the disc as grains decouple from the low-density wind. Entrainment is a strong function of location in the disc, resulting in a size sorting of grains in the outflow - the largest grain being carried out between 10 and 20 au. The peak dust density for each grain size occurs at the inner edge of its own entrainment region.

  20. Effect of algae on flocculation of suspended bed sediments in a large shallow lake. Consequences for ecology and sediment transport processes

    NASA Astrophysics Data System (ADS)

    de Lucas Pardo, Miguel Angel; Sarpe, Dirk; Winterwerp, Johan Christian

    2015-06-01

    Lake Markermeer, a large shallow lake in The Netherlands, suffers from turbidity and ecology problems. As part of a study aiming to mitigate these problems, we study flocculation processes in the lake; in particular, the possible mutual flocculation between algae and re-suspended bed sediments. We show that sediment re-suspended from the bed of the lake can flocculate, forming flocs for which size is a function of the turbulence level in the water column. Moreover, we also demonstrate that algae and re-suspended bed sediments can mutually flocculate, yielding organic-inorganic aggregates. These aggregates have different features to those of their individual components, some of which have been measured and characterized in this paper. Furthermore, the characteristics of the resulting organic-inorganic flocs are strongly influenced by the type of algae in the aggregate. We found that, in the case of flocs consisting of bed sediments and filamentous algae, flocculation yields smaller flocs than for bed sediments only, resulting in an increased turbidity in the water column. In the case of flocs consisting of bed sediments and colonial algae, flocs grow faster and become larger than bed sediment flocs, which may result in the depletion of most colonies from the water column.

  1. Individual Differences in Rhythmic Cortical Entrainment Correlate with Predictive Behavior in Sensorimotor Synchronization

    PubMed Central

    Nozaradan, Sylvie; Peretz, Isabelle; Keller, Peter E.

    2016-01-01

    The current study aims at characterizing the mechanisms that allow humans to entrain the mind and body to incoming rhythmic sensory inputs in real time. We addressed this unresolved issue by examining the relationship between covert neural processes and overt behavior in the context of musical rhythm. We measured temporal prediction abilities, sensorimotor synchronization accuracy and neural entrainment to auditory rhythms as captured using an EEG frequency-tagging approach. Importantly, movement synchronization accuracy with a rhythmic beat could be explained by the amplitude of neural activity selectively locked with the beat period when listening to the rhythmic inputs. Furthermore, stronger endogenous neural entrainment at the beat frequency was associated with superior temporal prediction abilities. Together, these results reveal a direct link between cortical and behavioral measures of rhythmic entrainment, thus providing evidence that frequency-tagged brain activity has functional relevance for beat perception and synchronization. PMID:26847160

  2. Strong effects of network architecture in the entrainment of coupled oscillator systems

    NASA Astrophysics Data System (ADS)

    Kori, Hiroshi; Mikhailov, Alexander S.

    2006-12-01

    Random networks of coupled phase oscillators, representing an approximation for systems of coupled limit-cycle oscillators, are considered. Entrainment of such networks by periodic external forcing applied to a subset of their elements is numerically and analytically investigated. For a large class of interaction functions, we find that the entrainment window with a tongue shape becomes exponentially narrow for networks with higher hierarchical organization. However, the entrainment is significantly facilitated if the networks are directionally biased—i.e., closer to the feedforward networks. Furthermore, we show that the networks with high entrainment ability can be constructed by evolutionary optimization processes. The neural network structure of the master clock of the circadian rhythm in mammals is discussed from the viewpoint of our results.

  3. Individual Differences in Rhythmic Cortical Entrainment Correlate with Predictive Behavior in Sensorimotor Synchronization.

    PubMed

    Nozaradan, Sylvie; Peretz, Isabelle; Keller, Peter E

    2016-01-01

    The current study aims at characterizing the mechanisms that allow humans to entrain the mind and body to incoming rhythmic sensory inputs in real time. We addressed this unresolved issue by examining the relationship between covert neural processes and overt behavior in the context of musical rhythm. We measured temporal prediction abilities, sensorimotor synchronization accuracy and neural entrainment to auditory rhythms as captured using an EEG frequency-tagging approach. Importantly, movement synchronization accuracy with a rhythmic beat could be explained by the amplitude of neural activity selectively locked with the beat period when listening to the rhythmic inputs. Furthermore, stronger endogenous neural entrainment at the beat frequency was associated with superior temporal prediction abilities. Together, these results reveal a direct link between cortical and behavioral measures of rhythmic entrainment, thus providing evidence that frequency-tagged brain activity has functional relevance for beat perception and synchronization. PMID:26847160

  4. Influence of simulated MSW sizes on the combustion process in a fixed bed: CFD and experimental approaches.

    PubMed

    Sun, Rui; Ismail, Tamer M; Ren, Xiaohan; Abd El-Salam, M

    2016-03-01

    This work presents the effect of the simulated sizes of Municipal Solid Waste (MSW) on the combustion process in a fixed bed experimentally and numerically. The effect of temperature, gas emissions, flame front velocity and process rate are discussed for three different sizes of MSW: 10, 30, and 50 mm. The study found that for the operating conditions of the current model, when the diameter of particles is decreased, the bulk density of the material is increased, resulting in a decrease of convective heat transfer as well as combustion speed. As the diameter size of the material particles increase, the height of the post-combustion zone is increased, while the temperature in a high temperature area is decreased, due to the decrease in the material's bulk density and the excessive increase in porosity. Results also show that the average emission concentration of CO and CO2 decreases gradually with an increase in the particle diameter size.

  5. Influence of simulated MSW sizes on the combustion process in a fixed bed: CFD and experimental approaches.

    PubMed

    Sun, Rui; Ismail, Tamer M; Ren, Xiaohan; Abd El-Salam, M

    2016-03-01

    This work presents the effect of the simulated sizes of Municipal Solid Waste (MSW) on the combustion process in a fixed bed experimentally and numerically. The effect of temperature, gas emissions, flame front velocity and process rate are discussed for three different sizes of MSW: 10, 30, and 50 mm. The study found that for the operating conditions of the current model, when the diameter of particles is decreased, the bulk density of the material is increased, resulting in a decrease of convective heat transfer as well as combustion speed. As the diameter size of the material particles increase, the height of the post-combustion zone is increased, while the temperature in a high temperature area is decreased, due to the decrease in the material's bulk density and the excessive increase in porosity. Results also show that the average emission concentration of CO and CO2 decreases gradually with an increase in the particle diameter size. PMID:26750870

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

    PubMed Central

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

    2013-01-01

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

  7. Entrainment of respiratory frequency to exercise rhythm during hypoxia.

    PubMed

    Paterson, D J; Wood, G A; Marshall, R N; Morton, A R; Harrison, A B

    1987-05-01

    Breathing frequency (f) is often reported as having an integer-multiple relationship to limb movement (entrainment) during rhythmic exercise. To investigate the strength of this coupling while running under hypoxic conditions, two male Caucasians and four male Nepalese porters were tested in the Annapurna region of the Himalayas at altitudes of 915, 2,135, 3,200, 4,420, and 5,030 m. In an additional study in a laboratory at sea level, three male and four female subjects inspired various O2-N2 mixtures [fraction of inspired O2 (FIO2) = 20.93, 17.39, 14.40, 11.81%] that were administered in a single-blind randomized fashion during a treadmill run (40% FIO2 maximum O2 consumption). Breathing and gait signals were stored on FM tape and later processed on a PDP 11/73 computer. The subharmonic relationships between these signals were determined from Fourier analysis (power spectrum), and the coincidence of coupling occurrence was statistically modeled. Entrainment decreased linearly during increasing hypoxia (P less than 0.01). Moreover, a significant linear increase in f occurred during hypoxia (P less than 0.05), whereas stride frequency and metabolic rate remained constant, suggesting that hypoxic-induced increases in f decreased the degree of entrainment. PMID:3597249

  8. The Entrainment Interface Layer of Stratocumulus-topped Boundary Layers

    NASA Astrophysics Data System (ADS)

    Krueger, S.; Hill, S.

    2010-09-01

    The entrainment interface layer (EIL) is the layer between cloud top and the free atmosphere. It contains mixtures of air from the cloud layer and the free atmosphere. In addition to turbulent mixing, phase changes and radiative heating or ccoling also affect the thermodynamic properties of air in the EIL. Eventually, air from the EIL is entrained into the cloud layer. How do processes in the EIL affect the entrainment rate? What is the structure of the EIL? Is cloud-top an interface (a region of high gradients), or simply an iso-surface? We are using airborne measuurements taken in the EIL during POST (Physics of Stratocumulus Top), which took place during July and August 2008 near Monterey, California, USA, to address these questions. High-rate measurements of temperature and liquid water content made just 0.5 m apart allow us to perform a high-resolution analysis of a conserved variable (liquid water potential temperature). When combined with lower-rate measurements of water vapor, they also allow us to perform a mixture fraction analysis following vanZanten and Duynkerke (2002).

  9. Velocity response curves demonstrate the complexity of modeling entrainable clocks.

    PubMed

    Taylor, Stephanie R; Cheever, Allyson; Harmon, Sarah M

    2014-12-21

    Circadian clocks are biological oscillators that regulate daily behaviors in organisms across the kingdoms of life. Their rhythms are generated by complex systems, generally involving interlocked regulatory feedback loops. These rhythms are entrained by the daily light/dark cycle, ensuring that the internal clock time is coordinated with the environment. Mathematical models play an important role in understanding how the components work together to function as a clock which can be entrained by light. For a clock to entrain, it must be possible for it to be sped up or slowed down at appropriate times. To understand how biophysical processes affect the speed of the clock, one can compute velocity response curves (VRCs). Here, in a case study involving the fruit fly clock, we demonstrate that VRC analysis provides insight into a clock׳s response to light. We also show that biochemical mechanisms and parameters together determine a model׳s ability to respond realistically to light. The implication is that, if one is developing a model and its current form has an unrealistic response to light, then one must reexamine one׳s model structure, because searching for better parameter values is unlikely to lead to a realistic response to light. PMID:25193284

  10. Flowmeter for gas-entrained solids flow

    DOEpatents

    Porges, Karl G.

    1990-01-01

    An apparatus and method for the measurement of solids feedrate in a gas-entrained solids flow conveyance system. The apparatus and method of the present invention include a vertical duct connecting a source of solids to the gas-entrained flow conveyance system, a control valve positioned in the vertical duct, and a capacitive densitometer positioned along the duct at a location a known distance below the control valved so that the solid feedrate, Q, of the gas entrained flow can be determined by Q=S.rho..phi.V.sub.S where S is the cross sectional area of the duct, .rho. is the density of the solid, .phi. is the solid volume fraction determined by the capacitive densitometer, and v.sub.S is the local solid velocity which can be inferred from the konown distance of the capacitive densitometer below the control valve.

  11. Apparatus for controlling fluidized beds

    DOEpatents

    Rehmat, A.G.; Patel, J.G.

    1987-05-12

    An apparatus and process are disclosed for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance. 2 figs.

  12. Apparatus for controlling fluidized beds

    DOEpatents

    Rehmat, Amirali G.; Patel, Jitendra G.

    1987-05-12

    An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

  13. Numerical Modeling of Deep Mantle Flow: Thermochemical Convection and Entrainment

    NASA Astrophysics Data System (ADS)

    Mulyukova, Elvira; Steinberger, Bernhard; Dabrowski, Marcin; Sobolev, Stephan

    2013-04-01

    ) upwelling of the ambient material in the vicinity of the dense material (mechanism of selective withdrawal (Lister, 1989)), and (iii) cold downwellings sliding along the bottom boundary, and forcing the dense material upwards. The objective of this study is to compare the efficiency of entrainment by each of these mechanisms, and its dependence on the density and viscosity anomaly of the dense material with respect to the ambient mantle. To perform this study, we have developed a two-dimensional FEM code to model thermal convection in a hollow cylinder domain with presence of chemical heterogeneities, and using a realistic viscosity profile. We present the results of the simulations that demonstrate the entrainment mechanisms described above. In addition, we perfom numerical experiments in a Cartesian box domain, where the bottom right boundary of the box is deformed to resemble the geometry of an LLSVP edge. In some of the experiments, the bottom left part of the boundary is moving towards the right boundary, simulating a slab sliding along the core-mantle boundary towards an LLSVP. These experiments allow a detailed study of the process of entrainment, and its role in the thermochemical evolution of the Earth.

  14. Bed bugs.

    PubMed

    Foulke, Galen T; Anderson, Bryan E

    2014-09-01

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

  15. A highly efficient polyampholyte hydrogel sorbent based fixed-bed process for heavy metal removal in actual industrial effluent.

    PubMed

    Zhou, Guiyin; Luo, Jinming; Liu, Chengbin; Chu, Lin; Ma, Jianhong; Tang, Yanhong; Zeng, Zebing; Luo, Shenglian

    2016-02-01

    High sorption capacity, high sorption rate, and fast separation and regeneration for qualified sorbents used in removing heavy metals from wastewater are urgently needed. In this study, a polyampholyte hydrogel was well designed and prepared via a simple radical polymerization procedure. Due to the remarkable mechanical strength, the three-dimensional polyampholyte hydrogel could be fast separated, easily regenerated and highly reused. The sorption capacities were as high as 216.1 mg/g for Pb(II) and 153.8 mg/g for Cd(II) owing to the existence of the large number of active groups. The adsorption could be conducted in a wide pH range of 3-6 and the equilibrium fast reached in 30 min due to its excellent water penetration for highly accessible to metal ions. The fixed-bed column sorption results indicated that the polyampholyte hydrogel was particularly effective in removing Pb(II) and Cd(II) from actual industrial effluent to meet the regulatory requirements. The treatment volumes of actual smelting effluent using one fixed bed column were as high as 684 bed volumes (BV) (7736 mL) for Pb(II) and 200 BV (2262 mL) for Cd(II). Furthermore, the treatment volumes of actual smelting effluent using tandem three columns reached 924 BV (31,351 mL) for Pb(II) and 250 BV (8483 mL) for Cd(II), producing only 4 BV (136 mL) eluent. Compared with the traditional high density slurry (HDS) process with large amount of sludge, the proposed process would be expected to produce only a small amount of sludge. When the treatment volume was controlled below 209.3 BV (7103 mL), all metal ions in the actual industrial effluent could be effectively removed (<0.01 mg/L). This wok develops a highly practical process based on polyampholyte hydrogel sorbents for the removal of heavy metal ions from practical wastewater.

  16. Methods of forming a fluidized bed of circulating particles

    DOEpatents

    Marshall, Douglas W.

    2011-05-24

    There is disclosed an apparatus for forming a fluidized bed of circulating particles. In an embodiment, the apparatus includes a bottom portion having a sidewall, the sidewall defining a curvilinear profile, and the bottom portion configured to contain a bed of particles; and a gas inlet configured to produce a column of gas to carry entrained particles therein. There is disclosed a method of forming a fluidized bed of circulating particles. In an embodiment, the method includes positioning particles within a bottom portion having a sidewall, the sidewall defining a curvilinear profile; producing a column of gas directed upwardly through a gas inlet; carrying entrained particles in the column of gas to produce a fountain of particles over the fluidized bed of circulating particles and subside in the particle bed until being directed inwardly into the column of gas within the curvilinear profile.

  17. Optimal performance of single-column chromatography and simulated moving bed processes for the separation of optical isomers

    NASA Astrophysics Data System (ADS)

    Medi, Bijan; Kazi, Monzure-Khoda; Amanullah, Mohammad

    2013-06-01

    Chromatography has been established as the method of choice for the separation and purification of optically pure drugs which has a market size of about 250 billion USD. Single column chromatography (SCC) is commonly used in the development and testing phase of drug development while multi-column Simulated Moving Bed (SMB) chromatography is more suitable for large scale production due to its continuous nature. In this study, optimal performance of SCC and SMB processes for the separation of optical isomers under linear and overloaded separation conditions has been investigated. The performance indicators, namely productivity and desorbent requirement have been compared under geometric similarity for the separation of a mixture of guaifenesin, and Tröger's base enantiomers. SCC process has been analyzed under equilibrium assumption i.e., assuming infinite column efficiency, and zero dispersion, and its optimal performance parameters are compared with the optimal prediction of an SMB process by triangle theory. Simulation results obtained using actual experimental data indicate that SCC may compete with SMB in terms of productivity depending on the molecules to be separated. Besides, insights into the process performances in terms of degree of freedom and relationship between the optimal operating point and solubility limit of the optical isomers have been ascertained. This investigation enables appropriate selection of single or multi-column chromatographic processes based on column packing properties and isotherm parameters.

  18. Application of the upflow anaerobic sludge bed (UASB) process for treatment of complex wastewaters at low temperatures

    SciTech Connect

    Koster, I.W.; Lettinga, G.

    1985-10-01

    The feasibility of the upflow anaerobic sludge bed (UASB) process for the treatment of potato starch wastewater at low ambient temperatures was demonstrated by operating two 5.65 l reactors at 14 degrees C and 20 degrees C, respectively. The organic space loading rates achieved in these laboratory-scale reactors were 3 kg COD/cubic m/day at 14 degrees C and 4-5 kg COD/cubic m/day at 20 degrees C. The corresponding sludge loading rates were 0.12 kg COD/kg VSS/day at 14 degrees C and 0.16-0.18 kg COD/kg VSS/day at 20 degrees C. These findings are of considerable practical importance because application of anaerobic treatment at low ambient temperatures will lead to considerable savings in energy needed for operating the process. As compared with various other anaerobic wastewater treatment processes, a granular sludge upflow process represents one of the best options developed so far. Although the overall sludge yield under psychrophilic conditions is slightly higher than under optimal mesophilic conditions, this doesn't seriously hamper the operation of the process. The extra sludge yield, due to accumulation of slowly hydrolyzing substrate ingredients, was 4.75% of the COD input at 14 degrees C and 1.22% of the COD input at 20 degrees C. 26 references.

  19. Neural Entrainment to Rhythmically Presented Auditory, Visual, and Audio-Visual Speech in Children

    PubMed Central

    Power, Alan James; Mead, Natasha; Barnes, Lisa; Goswami, Usha

    2012-01-01

    Auditory cortical oscillations have been proposed to play an important role in speech perception. It is suggested that the brain may take temporal “samples” of information from the speech stream at different rates, phase resetting ongoing oscillations so that they are aligned with similar frequency bands in the input (“phase locking”). Information from these frequency bands is then bound together for speech perception. To date, there are no explorations of neural phase locking and entrainment to speech input in children. However, it is clear from studies of language acquisition that infants use both visual speech information and auditory speech information in learning. In order to study neural entrainment to speech in typically developing children, we use a rhythmic entrainment paradigm (underlying 2 Hz or delta rate) based on repetition of the syllable “ba,” presented in either the auditory modality alone, the visual modality alone, or as auditory-visual speech (via a “talking head”). To ensure attention to the task, children aged 13 years were asked to press a button as fast as possible when the “ba” stimulus violated the rhythm for each stream type. Rhythmic violation depended on delaying the occurrence of a “ba” in the isochronous stream. Neural entrainment was demonstrated for all stream types, and individual differences in standardized measures of language processing were related to auditory entrainment at the theta rate. Further, there was significant modulation of the preferred phase of auditory entrainment in the theta band when visual speech cues were present, indicating cross-modal phase resetting. The rhythmic entrainment paradigm developed here offers a method for exploring individual differences in oscillatory phase locking during development. In particular, a method for assessing neural entrainment and cross-modal phase resetting would be useful for exploring developmental learning difficulties thought to involve temporal

  20. Entrainment of riparian gravel and cobbles in an alluvial reach of a regulated canyon river

    USGS Publications Warehouse

    Elliotp, J.G.; Hammack, L.A.

    2000-01-01

    Many canyon rivers have channels and riparian zones composed of alluvial materials and these reaches, dominated by fluvial processes, are sensitive to alterations in streamflow regime. Prior to reservoir construction in the mid-1960s, banks and bars in alluvial reaches of the Gunnison River in the Black Canyon National Monument, Colorado, USA, periodically were reworked and cleared of riparian vegetation by mainstem floods. Recent interest in maintaining near-natural conditions in the Black Canyon using reservoir releases has created a need to estimate sediment-entraining discharges for a variety of geomorphic surfaces composed of sediment ranging in size from gravel to small boulders. Sediment entrainment potential was studied at eight cross-sections in an alluvial reach of the Gunnison River in the Black Canyon in 1994 and 1995. A one-dimensional water-surface profile model was used to estimate water-surface elevations, flow depths, and hydraulic conditions on selected alluvial surfaces for discharges ranging from 57 to 570 m3/s. Onsite observations before and after a flood of 270 m3/s confirmed sediment entrainment on several surfaces inundated by the flood. Selective entrainment of all but the largest particle sizes on the surface occurred at some locations. Physical evidence of sediment entrainment, or absence of sediment entrainment, on inundated surfaces generally was consistent with critical shear stresses estimated with a dimensionless critical shear stress of 0.030. Sediment-entrainment potential over a range of discharges was summarized by the ratio of the local boundary shear stress to the critical shear stress for d50, given hydraulic geometry and sediment-size characteristics. Differing entrainment potential for similar geomorphic surfaces indicates that estimation of minimum streamflow requirements based on sediment mobility is site-specific and that there is no unique streamflow that will initiate movement of d50 at every geomorphically similar

  1. Treatment of wastewater from coffee bean processing in anaerobic fixed bed reactors with different support materials: performance and kinetic modeling.

    PubMed

    Fia, Fátima R L; Matos, Antonio T; Borges, Alisson C; Fia, Ronaldo; Cecon, Paulo R

    2012-10-15

    An evaluation was performed of three upflow anaerobic fixed bed reactors for the treatment of wastewater from coffee bean processing (WCP). The supports used were: blast furnace cinders, polyurethane foam and crushed stone with porosities of 53, 95 and 48%, respectively. The testing of these 139.5 L reactors consisted of increasing the COD of the influent (978; 2401 and 4545 mg L(-1)), while maintaining the retention time of 1.3 days. For the maximum COD applied, the reactor filled with foam presented removals of 80% (non-filtered samples) and 83% (filtered samples). The greater performance of the reactor filled with foam is attributed to its porosity, which promoted greater collection of biomass. From the results, it could be concluded that the reactors presented satisfactory performance, especially when using the foam as a support. Furthermore, the modified Stover-Kincannon and second order for multicomponent substrate degradation models were successfully used to develop a model of the experimental data.

  2. Microbial community of sulfate-reducing up-flow sludge bed in the SANI® process for saline sewage treatment.

    PubMed

    Wang, Jin; Shi, Manyuan; Lu, Hui; Wu, Di; Shao, Ming-Fei; Zhang, Tong; Ekama, George A; van Loosdrecht, Mark C M; Chen, Guang-Hao

    2011-06-01

    This study investigated the microbial community of the sulfate-reducing up-flow sludge bed (SRUSB) of a novel sulfate reduction, autotrophic denitrification, and nitrification integrated (SANI®) process for saline sewage treatment. The investigation involved a lab-scale SANI® system treating synthetic saline sewage and a pilot-scale SANI® plant treating 10 m(3)/day of screened saline sewage. Sulfate-reducing bacteria (SRB) were the dominant population, responsible for more than 80% of the chemical oxygen demand removal, and no methane-producing archaea were detected in both SRUSBs. Thermotogales-like bacteria were the dominant SRB in the pilot-scale SRUSB while Desulforhopalus-like bacteria were the major species in the lab-scale SRUSB.

  3. A daily palatable meal without food deprivation entrains the suprachiasmatic nucleus of rats.

    PubMed

    Mendoza, Jorge; Angeles-Castellanos, Manuel; Escobar, Carolina

    2005-12-01

    Food is considered a potent Zeitgeber for peripheral oscillators but not for the suprachiasmatic nucleus (SCN), which is entrained principally by the light-dark cycle. However, when food attains relevant properties in quantity and quality, it can be a potent Zeitgeber even for the SCN. Here we evaluated the entrainment influence of a daily palatable meal, without regular food deprivation, on the circadian rhythm of locomotor activity and the c-Fos and PER-1 protein expression in the SCN. Rats fed ad libitum, in constant darkness, received a palatable meal for 6 weeks starting in the middle of the subjective day. Locomotor activity showed entrainment when the offset of activity coincided with the palatable meal-time. In the SCN, the peak expression of c-Fos was observed at palatable meal-time and PER-1 showed a peak during the onset of subjective night, as predicted according to the behavioural entrained pattern. In addition, c-Fos and PER-1 expression in the paraventricular thalamic nucleus (PVT) showed increased expression at palatable meal-time, while the intergeniculate leaflet did not, suggesting that the PVT may be involved as an input pathway of palatable food-entrainment to the SCN. These results demonstrate that daily access to a palatable meal can entrain the SCN; several stimuli can be implicated in this process, including motivation and arousal.

  4. Apparatus for fluid-bed catalytic reactions

    SciTech Connect

    Harandi, M.; Owen, H.

    1991-09-17

    This patent describes an apparatus for the conversion of hydrocarbons. It comprises a reactor vessel for containing a fluid bed reaction zone including finely divided catalyst, the reactor vessel further comprising a feed distributor positioned in a lower portion of the reactor vessel, a heat exchange conduit within the reactor vessel in direct contact with the fluid bed reaction zone for transferring heat from a hot circulating fluid to the fluid bed reaction zone, and a catalyst separator positioned in an upper section of the reactor vessel for segregating reaction products from entrained spent catalyst; a first conduit for withdrawing spent catalyst from the fluid bed reaction zone; a feed preheater vessel operatively connected to the first conduit for contacting an aliphatic feedstream with a fluidized bed of the spent catalyst, the feed preheater vessel being sized to provide spent catalyst circulation through the preheater vessel of from about 0.1 to about 100 volumes of spent catalyst per hour.

  5. Fluidized bed combustion: Mechanical systems and chemical processes. December 1973-March 1990 (A Bibliography from the NTIS data base). Report for December 1973-March 1990

    SciTech Connect

    Not Available

    1990-03-01

    This bibliography contains citations concerning research and development activities of mechanical systems and chemical processes pertaining to fluidized-bed combustion systems. Descriptions and evaluations of the following topics are considered: combustion and ignition studies, mechanical elements, heating and cooling systems, industrial chemistry, and chemical-process engineering. (Contains 286 citations fully indexed and including a title list.)

  6. Laminar Entrained Flow Reactor (Fact Sheet)

    SciTech Connect

    Not Available

    2014-02-01

    The Laminar Entrained Flow Reactor (LEFR) is a modular, lab scale, single-user reactor for the study of catalytic fast pyrolysis (CFP). This system can be employed to study a variety of reactor conditions for both in situ and ex situ CFP.

  7. Washing of the AW-101 entrained solids

    SciTech Connect

    GJ Lumetta

    2000-03-31

    BNFL Inc. (BNFL) is under contract with the US Department of Energy, River Protection Project (DOE-RPP) to design, construct, and operate facilities for treating wastes stored in the single-shell and double-shell tanks at the Hanford Site, Richland, Washington. The DOE-BNFL RPP contract identifies two feeds to the waste treatment plant: (1) primarily liquid low-activity waste (LAW) consisting of less than 2 wt% entrained solids and (2) high-level waste (HLW) consisting of 10 to 200 g/L solids slurry. This report describes the results of a test conducted by Battelle to assess the effects of inhibited water washing on the composition of the entrained solids in the diluted AW-101 low-activity waste (LAW) sample. The objective of this work was to gather data on the solubility of the AW-101 entrained solids in 0.01 M NaOH, so that BNFL can evaluate whether these solids require caustic leaching. The work was conducted according to test plan BNFL-TP-29953-9, Rev. 0, LAW Entrained Solids Water Wash and Caustic Leach Testing. The test went according to plan, with no deviations from the test plan. Based on the results of the 0.01 M NaOH washing, a decision was made by BNFL to not proceed with the caustic leaching test. The composition of the washed solids was such that caustic leaching would not result in significant reduction in the immobilized HLW volume.

  8. Online process control of a pharmaceutical intermediate in a fluidized-bed drier environment using near-infrared spectroscopy.

    PubMed

    Märk, Julia; Karner, Martin; Andre, Max; Rueland, Jochen; Huck, Christian W

    2010-05-15

    In the production plant of an antibiotic substance, a new fluidized-bed drier has been installed. For online process control of the drying progress and determination of the ideal drying end point, a continuous near-infrared spectroscopic (NIRS) measuring setup was implemented to rapidly and simultaneously gain all essential product information. A bypass system outside the drier combined with a robust process probe proved to provide the best sampling system geometry. The spectrometer was equipped with an additional laboratory probe for complementary offline analysis. Multivariate calibrations for product assay, water content, and residual solvent were calculated, optimized, and compared for the two probes. The final root-mean-square error of cross validation (RMSECV) for the process probe could be reduced to 0.81% for the product assay, 0.25% for water, and 0.06% for acetone. The laboratory-probe prediction values show good agreement with reference data during the testing period. The calibrations of the process probe were checked by comparing its predictions to those of the validated laboratory probe. The monitoring system could be automated to a large extent, and product quality could be improved considerably. The established technology is of high importance for the pharmaceutical industry carrying out high-throughput routine analysis because of its advantages in terms of of time and cost reductions.

  9. Cloud top entrainment instability and cloud top distributions

    NASA Technical Reports Server (NTRS)

    Boers, Reinout; Spinhirne, James D.

    1990-01-01

    Classical cloud-top entrainment instability condition formulation is discussed. A saturation point diagram is used to investigate the details of mixing in cases where the cloud-top entrainment instability criterion is satisfied.

  10. HIGH SPATIAL RESOLUTION SURVEY OF GRAIN SIZE INFORMATION ON RIVER BED BY IMAGE PROCESSING

    NASA Astrophysics Data System (ADS)

    Ohashi, Keisuke; Ihara, Kazuki; Yasuda, Shingo

    We tried a method of grain sizing by image processing which is available to survey and analyze in short time. The high-efficiency method actualizes high spatial resolution information of grain size distribution. Thus, the information has a vailability to express a situation of stream flow better than traditional grain sizing methods. For this reason, we paid attention to 50 m reservoir area upper from the check dam in mountainous region and surveyed the grain distribution at 26 sites and river channel landform. The grain sizing by image processing provided the appropriate result qualitatively. Moreover we estimated the critical diameter of moving from hydraulic information simultaneously. A qualitative appropriate result is showed less than 50 mm error as a result, however, quantitative response is not found between the critical diameter of moving and the grain size distribution surveyed. Meanwhile,the different grain sizing methods that are image processing and traditional sieving are used to cover the bilateral weak point. Thereby, a peak of grain existence probability is found in the threshold diameter between image processing and sieving. This result indicates that it is necessary to change the threshold diameter much larger than the limit of image processing grain sizing.

  11. Entrainment and Microphysics in DYCOMS-II Stratocumulus

    NASA Astrophysics Data System (ADS)

    Gerber, H. E.; Frick, G.; Malinowski, S.; Burnet, F.; Brenguier, J.

    2005-12-01

    During the nine DYCOMS-II flights through stratocumulus (Sc) off the California Coast with the NCAR C-130 research aircraft measurements of thermodynamics and microphysics were made with unprecedented resolution by three co-located probes. The UFT (ultra-fast temperature probe; U. of Warsaw) and the PVM (LWC and effective radius; Gerber Scientific) measured incloud with a resolution of 10 cm, and the FFSSP (fast FSSP; Meteo-France) measured with a resolution of 2 m. Our measurements and their analyses have led to an improved understanding of the physical processes associated with entrainment and its affect on Sc microphysics. We describe our results including the following: Cloud-top interacts with the warm and dry free atmosphere above the Sc to create the EIL (entrainment interface layer) several tens of m thick on the average. Further cloud detrains and mixes with the EIL to generate cloud-free moisture and temperature conditions ranging between cloud-top and free-atmosphere conditions. Buoyancy sorting occurs in the EIL with some parcels approaching the buoyancy at cloud-top. At that point these parcels enter cloud in a near thermodynamically-neutral fashion as shown by comparing UFT measurements in entrainment features ("cloud holes") with unaffected adjacent cloud, and in a mixing manner that resembles inhomogeneous mixing by diluting droplet number but not reducing their size as shown by the PVM and the FFSSP. This behavior occurs despite nearly all the Sc showing strong CTEI (cloud-top entrainment instability). Thus cooling due to the evaporation of cloud water contributes a negligible amount to buoyancy production at cloud top, it simply contributes a small amount to conditioning the EIL. Further, supersaturation transients caused by mixing of saturated parcels at different temperature near cloud top are not present. We find that the holes with LWC reduced by entrainment and embedded in down-welling regions caused by radiative cooling can reach their SEL

  12. Treatment of oil sands process-affected water using moving bed biofilm reactors: With and without ozone pretreatment.

    PubMed

    Shi, Yijing; Huang, Chunkai; Rocha, Ketley Costa; El-Din, Mohamed Gamal; Liu, Yang

    2015-09-01

    Two moving bed biofilm reactors (MBBRs) were operated to treat raw (untreated) and 30 mg/L ozone-treated oil sands process-affected water (OSPW). After 210 days, the MBBR process showed 18.3% of acid-extractable fraction (AEF) and 34.8% of naphthenic acids (NAs) removal, while the ozonation combined MBBR process showed higher removal of AEF (41.0%) and NAs (78.8%). Biodegradation of raw and ozone treated OSPW showed similar performance. UPLC/HRMS analysis showed a highest NAs removal efficiency with a carbon number of 14 and a -Z number of 4. Confocal laser scanning microscopy (CLSM) showed thicker biofilms in the raw OSPW MBBR (97 ± 5 μm) than in the ozonated OSPW MBBR (71 ± 12 μm). Quantitative polymerase chain reaction (q-PCR) results showed higher abundance of gene copies of total bacteria and nitrogen removal relevant bacteria in the ozonated OSPW MBBR, but no significant difference was found. MiSeq sequencing showed Proteobacteria, Nitrospirae, and Acidobacteria were dominant. PMID:26038326

  13. Treatment of oil sands process-affected water using moving bed biofilm reactors: With and without ozone pretreatment.

    PubMed

    Shi, Yijing; Huang, Chunkai; Rocha, Ketley Costa; El-Din, Mohamed Gamal; Liu, Yang

    2015-09-01

    Two moving bed biofilm reactors (MBBRs) were operated to treat raw (untreated) and 30 mg/L ozone-treated oil sands process-affected water (OSPW). After 210 days, the MBBR process showed 18.3% of acid-extractable fraction (AEF) and 34.8% of naphthenic acids (NAs) removal, while the ozonation combined MBBR process showed higher removal of AEF (41.0%) and NAs (78.8%). Biodegradation of raw and ozone treated OSPW showed similar performance. UPLC/HRMS analysis showed a highest NAs removal efficiency with a carbon number of 14 and a -Z number of 4. Confocal laser scanning microscopy (CLSM) showed thicker biofilms in the raw OSPW MBBR (97 ± 5 μm) than in the ozonated OSPW MBBR (71 ± 12 μm). Quantitative polymerase chain reaction (q-PCR) results showed higher abundance of gene copies of total bacteria and nitrogen removal relevant bacteria in the ozonated OSPW MBBR, but no significant difference was found. MiSeq sequencing showed Proteobacteria, Nitrospirae, and Acidobacteria were dominant.

  14. A compact process for treating oilfield wastewater by combining hydrolysis acidification, moving bed biofilm, ozonation and biologically activated carbon techniques.

    PubMed

    Zheng, Tao

    2016-01-01

    A lab-scale hybrid system integrating a hybrid hydrolysis acidification (HA) reactor, a moving bed biofilm reactor (MBBR) and an ozonation-biologically activated carbon (O3-BAC) unit was used in the treatment of heavy oil wastewater with high chemical oxygen demand (COD) and low biodegradability. The effects of hydraulic retention time and ozonation time were investigated. The results show that under the optimal conditions, the effluent concentrations of COD, oil and ammonia were 48, 1.3 and 3.5 mg/L, respectively, corresponding to total removal efficiencies of 95.8%, 98.9% and 94.4%, respectively. The effluent could meet the grade I as required by the national discharge standard of China. The HA process remarkably improved the biodegradability of the wastewater, while the MBBR process played an important role in degrading COD. The ozonation process further enhanced the biodegradability of the MBBR effluent, and finally, deep treatment was completed in the BAC reactor. This work demonstrates that the hybrid HA/MBBR/O3-BAC system has the potential to be used for the treatment of high-strength oilfield wastewater.

  15. ENTRAINMENT BY LIGAMENT-CONTROLLED EFFERVESCENT ATOMIZER-PRODUCED SPRAYS

    EPA Science Inventory

    Entrainment of ambient air into sprays produced by a new type of effervescent atomizer is reported. Entrainment data were obtained using a device similar to that described by Ricou & Spalding (1961). Entrainment data were analyzed using the model of Bush & Sojka (1994), in concer...

  16. Evaluating Effects of Floodplain Constriction Along a High Energy Gravel-Bed River: Snake River, WY

    NASA Astrophysics Data System (ADS)

    Leonard, Christina M.

    This study examined approximately 66 km of the Snake River, WY, USA, spanning a natural reach within Grand Teton National Park and a reach immediately downstream that is confined by artificial levees. We linked the channel adjustments observed within these two reaches between 2007 and 2012 to sediment transport processes by developing a morphological sediment budget. A pair of digital elevation models (DEMs) was generated by fusing LiDAR topography with depth estimates derived from optical image data within wetted channels. Errors for both components of the DEMs (LiDAR and optical bathymetry) were propagated through the DEM of difference and sediment budget calculations. Our results indicated that even with the best available methods for acquiring high resolution topographic data over large areas, the uncertainty associated with bed elevation estimates implied that net volumetric changes were not statistically significant. In addition to the terrain analysis, we performed a tracer study to assess the mobility of different grain size classes in different morphological units. Grain sizes, hydraulic conditions, and flow resistance characteristics along cross-sections were used to calculate critical discharges for entrainment, but this bulk characterization of fluid driving forces failed to predict bed mobility. Our results indicated that over seasonal timescales specific grain classes were not preferentially entrained. Surface and subsurface grain size data were used to calculate armoring and dimensionless sediment transport ratios for both reaches; sediment supply exceeded transport capacity in the natural reach and vice versa in the confined reach. We used a conceptual model to describe channel adjustments to lateral constriction by levees. Initially we suggest levees focused flow energy and incised the bed, resulting in bed armoring. Bed armoring promoted channel widening, but levees prevented this and instead the channel migrated more rapidly within the

  17. Gaining fluid bed process understanding by in-line particle size analysis.

    PubMed

    Närvänen, Tero; Lipsanen, Tanja; Antikainen, Osmo; Räikkönen, Heikki; Heinämäki, Jyrki; Yliruusi, Jouko

    2009-03-01

    Different process phenomena and process failure modes could be monitored using the in-line particle size data measured by spatial filtering technique (SFT). In addition to the real-time granule growth monitoring, other events, such as the blocking of filter bags and the distributor plate, could be observed. SFT was used off-line, at-line and in-line in 14 differently manufactured granulation batches. No significant fouling occurred during the manufacturing due to the appropriate positioning of the probe. The off-line SFT results correlated well (R(2) = 0.97) with the sieve analysis results. It was also found that size segregation influenced both the in-line and at-line particle size results during the fluidization: in-line method underestimated and at-line method overestimated the final particle size.

  18. Bedload entrainment in low-gradient paraglacial coastal rivers of Maine, U.S.A.: Implications for habitat restoration

    NASA Astrophysics Data System (ADS)

    Snyder, Noah P.; Castele, Michael R.; Wright, Jed R.

    2009-02-01

    The rivers of coastal Maine flow through mainstem lakes and long low-gradient reaches that break the continuum of bedload transport expected in nonparaglacial landscapes. Stream erosion of glacial deposits supplies coarse sediment to these systems. The land use history includes intensive timber harvest and associated dam construction, which may have altered the frequency of substrate-mobilizing events. These watersheds are vital habitat for the last remaining wild anadromous Atlantic salmon in the United States. Future adjustments in channel morphology and habitat quality (via natural stream processes or restoration projects) depend on erosion, transport, and deposition of coarse sediment. These factors motivate our study of competence at four sites in the Sheepscot and Narraguagus watersheds. Three of the four sites behaved roughly similarly, with particle entrainment during intervals that include winter ice and spring flood conditions, and relatively minor bed mobilization during moderate floods in the summer and fall (with a recurrence interval of 2-3 years). The fourth site, on the Sheepscot River mainstem, exhibits more vigorous entrainment of marked particles and more complex three-dimensional channel morphology. This contrast is partially due to local geomorphic conditions that favor high shear stresses (particularly relatively steep gradient), but also likely to nourishment of the bedload saltation system by recruitment from an eroding glacial deposit upstream. Our results suggest that the frequency and magnitude of bedload transport are reach specific, depending on factors including local channel geometry, upstream sediment supply and transport, and formation of anchor ice. This presents a challenge for stream practitioners in this region: different reaches may require contrasting management strategies. Our results underscore the importance of understanding channel processes at a given site and assessing conditions upstream and downstream as a prerequisite

  19. HYDRODYNAMIC SIMULATIONS OF H ENTRAINMENT AT THE TOP OF He-SHELL FLASH CONVECTION

    SciTech Connect

    Woodward, Paul R.; Lin, Pei-Hung; Herwig, Falk E-mail: fherwig@uvic.ca

    2015-01-01

    We present the first three-dimensional, fully compressible gas-dynamics simulations in 4π geometry of He-shell flash convection with proton-rich fuel entrainment at the upper boundary. This work is motivated by the insufficiently understood observed consequences of the H-ingestion flash in post-asymptotic giant branch (post-AGB) stars (Sakurai's object) and metal-poor AGB stars. Our investigation is focused on the entrainment process at the top convection boundary and on the subsequent advection of H-rich material into deeper layers, and we therefore ignore the burning of the proton-rich fuel in this study. We find that for our deep convection zone, coherent convective motions of near global scale appear to dominate the flow. At the top boundary convective shear flows are stable against Kelvin-Helmholtz instabilities. However, such shear instabilities are induced by the boundary-layer separation in large-scale, opposing flows. This links the global nature of thick shell convection with the entrainment process. We establish the quantitative dependence of the entrainment rate on grid resolution. With our numerical technique, simulations with 1024{sup 3} cells or more are required to reach a numerical fidelity appropriate for this problem. However, only the result from the 1536{sup 3} simulation provides a clear indication that we approach convergence with regard to the entrainment rate. Our results demonstrate that our method, which is described in detail, can provide quantitative results related to entrainment and convective boundary mixing in deep stellar interior environments with very stiff convective boundaries. For the representative case we study in detail, we find an entrainment rate of 4.38 ± 1.48 × 10{sup –13} M {sub ☉} s{sup –1}.

  20. Apparatus for entrained coal pyrolysis

    DOEpatents

    Durai-Swamy, Kandaswamy

    1982-11-16

    This invention discloses a process and apparatus for pyrolyzing particulate coal by heating with a particulate solid heating media in a transport reactor. The invention tends to dampen fluctuations in the flow of heating media upstream of the pyrolysis zone, and by so doing forms a substantially continuous and substantially uniform annular column of heating media flowing downwardly along the inside diameter of the reactor. The invention is particularly useful for bituminous or agglomerative type coals.

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

    SciTech Connect

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

    2012-04-15

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

  2. Modifier mass transfer kinetic effect in the performance of solvent gradient simulated moving bed (SG-SMB) process

    NASA Astrophysics Data System (ADS)

    Câmara, L. D. T.

    2015-09-01

    The solvent-gradient simulated moving bed process (SG-SMB) is the new tendency in the performance improvement if compared to the traditional isocratic solvent conditions. In such SG-SMB separation process the modulation of the solvent strength leads to significant increase in the purities and productivity followed by reduction in the solvent consumption. A stepwise modelling approach was utilized in the representation of the interconnected chromatographic columns of the system combined with lumped mass transfer models between the solid and liquid phase. The influence of the solvent modifier was considered applying the Abel model which takes into account the effect of modifier volume fraction over the partition coefficient. The modelling and simulations were carried out and compared to the experimental SG-SMB separation of the amino acids phenylalanine and tryptophan. A lumped mass transfer kinetic model was applied for both the modifier (ethanol) as well as the solutes. The simulation results showed that such simple and global mass transfer models are enough to represent all the mass transfer effect between the solid adsorbent and the liquid phase. The separation performance can be improved reducing the interaction or the mass transfer kinetic effect between the solid adsorbent phase and the modifier. The simulations showed great agreement fitting the experimental data of the amino acids concentrations both at the extract as well as at the raffinate.

  3. Optimizing and modelling nitrogen removal in a new configuration of the moving-bed biofilm reactor process.

    PubMed

    Larrea, L; Albizuri, J; Abad, A; Larrea, A; Zalakain, G

    2007-01-01

    A new configuration of the moving-bed biofilm reactor process with pre-denitrification and nitrification was investigated in a pilot plant, which is fed with urban raw wastewater, the primary settler is located between the anoxic and the aerobic reactors, and primary sludge is recycled to the anoxic reactor as a hybrid pre-denitrification. The carriers used in the experiments are made of high-density polyethylene, with a diameter of 10 mm and a specific surface area of 400 m(2)/m(3). The new process was compared with conventional pre-denitrification-nitrification using in-series reactors fed with settled wastewater. The new configuration achieved an increase of 45% for the denitrification rate and of 30% for the nitrification rate when compared with conventional configuration. These results were analysed in light of the calibration study of the mixed-culture biofilm (MCB) model and simulations in AQUASIM 2.1 platform. Regarding denitrification, the high values obtained in the new configuration were attributed to a higher removal of the slowly biodegradable substrate (Xs) in the anoxic reactor due to the use of raw wastewater and sludge recycle. Accordingly, the amounts of heterotrophic biomass (XH) and Xs obtained in simulations were higher in both the biofilm and the bulk liquid. Regarding nitrification, the higher values were attributed to a lower removal of Xs in the aerobic reactors and accordingly, a lower accumulation of heterotrophic biomass in the biofilm was found in the simulations. PMID:17547001

  4. Improved fluid bed combustor efficiencies through fines recycle

    SciTech Connect

    Rickman, W.S.

    1980-04-01

    Carbon burnup efficiencies of 99.9% and higher have been attained on a 0.4-MW(t) atmospheric fluid bed combustor with fines recycle. A cyclone and sintered metal filter system separated the fines from the off-gas stream, returning them at 600/sup 0/C (1150/sup 0/F) to the fluid bed. The fines were metered through a unique rotary valve that also served as a pressure boundary between the fluid bed and the fines recycle hopper. Combustor operation was fully automated with a 100-channel process controller and supervisory computer. This high combustion efficiency is especially significant, since the fuel was graphite sized to less than 5 mm (1.3 in.) maximum size. More than 30% of the feed was fine enough to be quickly entrained, placing a substantial burden on the fines recycle system. Detailed modeling techniques were successfully developed to allow prediction of recycle rates and temperatures needed to maintain high combustion efficiency. This model has now been used to analyze coal combustion tests sponsored by Electric Power Research Institute. Surface reaction rate constants were first determined using combustor data taken during cold, low-flow fines recycle tests. These were then used to predict the effect of higher rates of recycle at various temperatures.

  5. AW-101 entrained solids - Solubility versus temperature

    SciTech Connect

    GJ Lumetta; RC Lettau; GF Piepel

    2000-03-31

    This report describes the results of a test conducted by Battelle to assess the solubility of the solids entrained in the diluted AW-101 low-activity waste (LAW) sample. BNFL requested Battelle to dilute the AW-1-1 sample using de-ionized water to mimic expected plant operating conditions. BNFL further requested Battelle to assess the solubility of the solids present in the diluted AW-101 sample versus temperature conditions of 30, 40, and 50 C. BNFL requested these tests to assess the composition of the LAW supernatant and solids versus expected plant-operating conditions. The work was conducted according to test plan BNFL-TP-29953-7, Rev. 0, Determination of the Solubility of LAW Entrained Solids. The test went according to plan, with no deviations from the test plan.

  6. Theoretical Investigation of the Process of Steam-Oxygen Gasification of Coke-Ash Particles in a Fluidized Bed Under Pressure

    NASA Astrophysics Data System (ADS)

    Rokhman, B. B.

    2015-03-01

    The problem on the evolution of the state of an ensemble of reacting coke-ash particles in a fluidized-bed gas generator is considered. A kinetic equation for the distribution function of particles within small ranges of carbon concentration variation for the stages of surface and bulk reaction has been constructed and integrated. Boundary conditions ("matching" conditions) at the boundaries between these ranges are formulated. The influence of the granulometric composition of the starting coal, height, porosity, and of the bed temperature on the process of steam-oxygen gasification of coke-ash particles of individual sorts of fuel and of a binary coal mixture has been investigated.

  7. THE SCALE-UP OF LARGE PRESSURIZED FLUIDIZED BEDS FOR ADVANCED COAL-FIRED POWER PROCESSES

    SciTech Connect

    Leon R. Glicksman; Michael Louge; Hesham F. Younis; Richard Tan; Mathew Hyre; Mark Torpey

    2003-11-24

    This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor an agency thereof, nor any of the their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, A combined-cycle High Performance Power System (HIPPS) capable of overall cycle efficiencies approaching 50% has been proposed and designed by Foster Wheeler Development Corporation (FWDC). A pyrolyzer in the first stage of the HIPPS process converts a coal feedstock into fuel gas and char at an elevated pressure of 1.4 Map. (206 psia) and elevated temperature of 930 C (1700 F). The generated char serves as the feedstock for a Pulverized Coal (PC) boiler operating at atmospheric pressure, and the fuel gas is directly fired in a gas turbine. The hydrodynamic behavior of the pyrolyzer strongly influences the quality of both the fuel gas and the generated char, the energy split between the gas turbine and the steam turbine, and hence the overall efficiency of the system. By utilizing a simplified set of scaling parameters (Glicksman et al.,1993), a 4/7th labscale cold model of the pyrolyzer operating at ambient temperature and pressure was constructed and tested. The scaling parameters matched include solid to gas density ratio, Froude number, length to diameter ratio; dimensionless superficial gas velocity and solid recycle rate, particle sphericity and particle size distribution (PSD).

  8. Rod Driven Frequency Entrainment and Resonance Phenomena

    PubMed Central

    Salchow, Christina; Strohmeier, Daniel; Klee, Sascha; Jannek, Dunja; Schiecke, Karin; Witte, Herbert; Nehorai, Arye; Haueisen, Jens

    2016-01-01

    A controversy exists on photic driving in the human visual cortex evoked by intermittent photic stimulation. Frequency entrainment and resonance phenomena are reported for frequencies higher than 12 Hz in some studies while missing in others. We hypothesized that this might be due to different experimental conditions, since both high and low intensity light stimulation were used. However, most studies do not report radiometric measurements, which makes it impossible to categorize the stimulation according to photopic, mesopic, and scotopic vision. Low intensity light stimulation might lead to scotopic vision, where rod perception dominates. In this study, we investigated photic driving for rod-dominated visual input under scotopic conditions. Twelve healthy volunteers were stimulated with low intensity light flashes at 20 stimulation frequencies, leading to rod activation only. The frequencies were multiples of the individual alpha frequency (α) of each volunteer in the range from 0.40 to 2.30∗α. Three hundred and six-channel whole head magnetoencephalography recordings were analyzed in time, frequency, and spatiotemporal domains with the Topographic Matching Pursuit algorithm. We found resonance phenomena and frequency entrainment for stimulations at or close to the individual alpha frequency (0.90–1.10∗α) and half of the alpha frequency (0.40–0.55∗α). No signs of resonance and frequency entrainment phenomena were revealed around 2.00∗α. Instead, on-responses at the beginning and off-responses at the end of each stimulation train were observed for the first time in a photic driving experiment at frequencies of 1.30–2.30∗α, indicating that the flicker fusion threshold was reached. All results, the resonance and entrainment as well as the fusion effects, provide evidence for rod-dominated photic driving in the visual cortex. PMID:27588002

  9. Rod Driven Frequency Entrainment and Resonance Phenomena.

    PubMed

    Salchow, Christina; Strohmeier, Daniel; Klee, Sascha; Jannek, Dunja; Schiecke, Karin; Witte, Herbert; Nehorai, Arye; Haueisen, Jens

    2016-01-01

    A controversy exists on photic driving in the human visual cortex evoked by intermittent photic stimulation. Frequency entrainment and resonance phenomena are reported for frequencies higher than 12 Hz in some studies while missing in others. We hypothesized that this might be due to different experimental conditions, since both high and low intensity light stimulation were used. However, most studies do not report radiometric measurements, which makes it impossible to categorize the stimulation according to photopic, mesopic, and scotopic vision. Low intensity light stimulation might lead to scotopic vision, where rod perception dominates. In this study, we investigated photic driving for rod-dominated visual input under scotopic conditions. Twelve healthy volunteers were stimulated with low intensity light flashes at 20 stimulation frequencies, leading to rod activation only. The frequencies were multiples of the individual alpha frequency (α) of each volunteer in the range from 0.40 to 2.30(∗)α. Three hundred and six-channel whole head magnetoencephalography recordings were analyzed in time, frequency, and spatiotemporal domains with the Topographic Matching Pursuit algorithm. We found resonance phenomena and frequency entrainment for stimulations at or close to the individual alpha frequency (0.90-1.10(∗)α) and half of the alpha frequency (0.40-0.55(∗)α). No signs of resonance and frequency entrainment phenomena were revealed around 2.00(∗)α. Instead, on-responses at the beginning and off-responses at the end of each stimulation train were observed for the first time in a photic driving experiment at frequencies of 1.30-2.30(∗)α, indicating that the flicker fusion threshold was reached. All results, the resonance and entrainment as well as the fusion effects, provide evidence for rod-dominated photic driving in the visual cortex. PMID:27588002

  10. Alignment strategies for the entrainment of music and movement rhythms.

    PubMed

    Moens, Bart; Leman, Marc

    2015-03-01

    Theories of entrainment assume that spontaneous entrainment emerges from dynamic laws that operate via mediators on interactions, whereby entrainment is facilitated if certain conditions are fulfilled. In this study, we show that mediators can be built that affect the entrainment of human locomotion to music. More specifically, we built D-Jogger, a music player that functions as a mediator between music and locomotion rhythms. The D-Jogger makes it possible to manipulate the timing differences between salient moments of the rhythms (beats and footfalls) through the manipulation of the musical period and phase, which affect the condition in which entrainment functions. We conducted several experiments to explore different strategies for manipulating the entrainment of locomotion and music. The results of these experiments showed that spontaneous entrainment can be manipulated, thereby suggesting different strategies on how to embark. The findings furthermore suggest a distinction among different modalities of entrainment: finding the beat (the most difficult part of entrainment), keeping the beat (easier, as a temporal scheme has been established), and being in phase (no entrainment is needed because the music is always adapted to the human rhythm). This study points to a new avenue of research on entrainment and opens new perspectives for the neuroscience of music.

  11. Treatment of food processing wastewater in a full-scale jet biogas internal loop anaerobic fluidized bed reactor.

    PubMed

    Wei, Chaohai; Zhang, Tao; Feng, Chunhua; Wu, Haizhen; Deng, Zhiyi; Wu, Chaofei; Lu, Bin

    2011-04-01

    A full-scale jet biogas internal loop anaerobic fluidized bed (JBILAFB) reactor, which requires low energy input and allows enhanced mass transfer, was constructed for the treatment of food processing wastewater. This reactor has an active volume of 798 m(3) and can treat 33.3 m(3) wastewater per hour. After pre-treating the raw wastewater by settling, oil separating and coagulation-air floating processes, the reactor was operated with a relatively shorter start-up time (55 days). Samples for the influent and effluent of the JBILAFB reactor were taken and analyzed daily for the whole process including both the start-up and stable running periods. When the volumetric COD loading fluctuated in the range of 1.6-5.6 kg COD m(-3) day(-1), the COD removal efficiency, the volatile fatty acid(VFA)/alkalinity ratio, the maximum biogas production and the content of CH(4) in total biogas of the reactor were found to be 80.1 ± 5%, 0.2-0.5, 348.5 m(3 )day(-1) and 94.5 ± 2.5%, respectively. Furthermore, the scanning electron microscope (SEM) results showed that anaerobic granular sludge and microorganism particles with biofilm coexisted in the reactor, and that the bacteria mainly in bacilli and cocci were observed as predominant species. All the data demonstrated that the enhanced mass transfer for gas, liquid and solid phases was achieved, and that the formation of microorganism granules and the removal of inhibitors increased the stability of the system.

  12. Interlinked Test Results for Fusion Fuel Processing and Blanket Tritium Recovery Systems Using Cryogenic Molecular Sieve Bed

    SciTech Connect

    Yamanishi, Toshihiko; Hayashi, Takumi; Kawamura, Yoshinori; Iwai, Yasunori; Isobe, Kanetsugu; Uzawa, Masayuki; Nishi, Masataka

    2005-07-15

    A simulated fuel processing (cryogenic distillation columns and a palladium diffuser) and CMSB (cryogenic molecular sieve bed) systems were linked together, and were operated. The validity of the CMSB was discussed through this experiment as an integrated system for the recovery of blanket tritium. A gas stream of hydrogen isotopes and He was supplied to the CMSB as the He sweep gas in blanket of a fusion reactor. After the breakthrough of tritium was observed, regeneration of the CMSB was carried out by evacuating and heating. The hydrogen isotopes were finally recovered by the diffuser. At first, only He gas was sent by the evacuating. The hydrogen isotopes gas was then rapidly released by the heating. The system worked well against the above drastic change of conditions. The amount of hydrogen isotopes gas finally recovered by the diffuser was in good agreement with that adsorbed by the CMSB. The dynamic behaviors (breakthrough and regeneration) of the system were explained well by a set of basic codes.

  13. Deammonification process start-up after enrichment of anammox microorganisms from reject water in a moving-bed biofilm reactor.

    PubMed

    Zekker, Ivar; Rikmann, Ergo; Tenno, Toomas; Kroon, Kristel; Vabamäe, Priit; Salo, Erik; Loorits, Liis; Rubin, Sergio S C dC; Vlaeminck, Siegfried E; Tenno, Taavo

    2013-01-01

    Deammonification via intermittent aeration in biofilm process for the treatment of sewage sludge digester supernatant (reject water) was started up using two opposite strategies. Two moving-bed biofilm reactors were operated for 2.5 years at 26 (+/- 0.5 degree C with spiked influent(and hence free ammonia (FA)) addition. In the first start-up strategy, an enrichment of anammox biomass was first established, followed by the development of nitrifying biomass in the system (R1). In contrast, the second strategy aimed at the enrichment of anammox organisms into a nitrifying biofilm (R2). The first strategy was most successful, reaching higher maximum total nitrogen (TN) removal rates over a shorter start-up period. For both reactors, increasing FA spiking frequency and increasing effluent concentrations of the anammox intermediate hydrazine correlated to decreasing aerobic nitrate production (nitritation). The bacterial consortium of aerobic and anaerobic ammonium oxidizing bacteria in the bioreactor was determined via denaturing gel gradient electrophoresis, polymerase chain reaction and pyrosequencing. In addition to a shorter start-up with a better TN removal rate, nitrite oxidizing bacteria (Nitrospira) were outcompeted by spiked ammonium feeding from R1.

  14. Inorganic nitrogen transformations in the bed of the Shingobee River, Minnesota: Integrating hydrologic and biological processes using sediment perfusion cores

    USGS Publications Warehouse

    Sheibley, R.W.; Duff, J.H.; Jackman, A.P.; Triska, F.J.

    2003-01-01

    Inorganic N transformations were examined in streambed sediments from the Shingobee River using sediment perfusion cores. The experimental design simulated groundwater-stream water mixing within sediment cores, which provided a well-defined one-dimensional representation of in situ hydrologic conditions. Two distinct hydrologic and chemical settings were preserved in the sediment cores: the lowermost sediments, perfused with groundwater, remained anaerobic during the incubations, whereas the uppermost sediments, perfused with oxic water pumped from the overlying water column, simulated stream water penetration into the bed. The maintenance of oxic and anoxic zones formed a biologically active aerobic-anaerobic interface. Ammonium (NH4+) dissolved in groundwater was transported conservatively through the lower core zone but was removed as it mixed with aerated recycle water. Concurrently, a small quantity of nitrate (NO3-) equaling ???25% of the NH4+ loss was produced in the upper sediments. The NH4+ and NO3- profiles in the uppermost sediments resulted from coupled nitrification-denitrification, because assimilation and sorption were negligible. We hypothesize that anaerobic microsites within the aerated upper sediments supported denitrification. Rates of nitrification and denitrification in the perfusion cores ranged 42-209 and 53-160 mg N m-2 day-1, respectively. The use of modified perfusion cores permitted the identification and quantification of N transformations and verified process control by surface water exchange into the shallow hyporheic zone of the Shingobee River.

  15. Physical Model and numerical modeling of earth-surface flows on erodible beds

    NASA Astrophysics Data System (ADS)

    Ouyang, Chaojun; He, Siming; Zhou, Gordan

    2015-04-01

    The bed sediment erosion and depositional processes along the channel play a significant role in geo-hazards like debris flows, landslides and dam failures. Large quantities of theoretical, experimental and field researches have shown that the final debris flow volume could possibly be several-fold beyond its initial volume as it incorporates material from the basal beds. A number of catastrophic events imply the damage is still generally underestimated, especially in the area influenced by strong earthquake such as Wenchuan 5.12 earthquake in 2008. An increasing number of researchers have been dedicated to using depth-integrated Na-vier-Stokes equations to determine the runout distance and final deposition volume of land-slides or debris flows over erodible beds. Nevertheless, it has been found out that the role of mass and momentum exchange at flow-bed boundaries in conservation equations was im-properly exhibited in some literatures, as reviewed by Iverson and Ouyang (2014). In addition, it is also illustrated that erosion or deposition rates at the interface between layers must satisfy three jump conditions which are similar to Rankine-Hugoniot conditions in gas dynamics. Here, several basal entrainment models satisfying the momentum jump conditions are proposed. Coupled mass and momentum equations integrated with sediment transport and morphological evolution are presented. A time and space second-order MacCormack-TVD finite difference method, which does not require the knowledge of the characteristic speeds of the system, is programmed to solve the coupled equations. A series of numerical simulations compared with theoretical solution and laboratory experiments were carried out to verify the accuracy and its robustness. Numerical comparisons with USGS flume experiment and Hongchun gully debris flow in Wenchuan earthquake-induced area are well carried out. It is exhibited the momentum exchange term between the flows and the basal materials has a sig

  16. Surge Across the Chambo: Entrainment, topographical influences, and flow transformation of pyroclastic density currents using a combined field and multiphase modeling approach

    NASA Astrophysics Data System (ADS)

    Benage, M. C.; Dufek, J.; Geist, D.; Harpp, K. S.

    2011-12-01

    simulations in concert with detailed measurements of these flows from both up flow and down flow from the transformation to document the process of dense to dilute flow transition. The field characterization includes mapping of the flows, grain size analysis, documenting flow direction indicators, comminution rounding, thermal proxies for air entrainment, and bed form documentation. We used a three-dimensional, multiphase (Eulerian-Eulerian-Lagrangian, EEL) modeling approach to describe size sorting, concentration gradients, and stresses in these evolving flows using the topography of the near Chambo River crossing (Dufek and Bergantz, 2007). The numerical models reveal extensive entrainment in the surge-generating phase of the flow, and secondary plume generation as fine ash in transported by hot gases higher into the atmosphere. Granular waves develop in the confined channels of the dense flow resulting bed shear stress perturbations. These granular instabilities and entrainment result in pulsing conditions in the surge, accounting for much of the unsteady behavior that results in fluctuations in grain size and bed form in the surge deposits.

  17. Word-by-word entrainment of speech rhythm during joint story building.

    PubMed

    Himberg, Tommi; Hirvenkari, Lotta; Mandel, Anne; Hari, Riitta

    2015-01-01

    Movements and behavior synchronize during social interaction at many levels, often unintentionally. During smooth conversation, for example, participants adapt to each others' speech rates. Here we aimed to find out to which extent speakers adapt their turn-taking rhythms during a story-building game. Nine sex-matched dyads of adults (12 males, 6 females) created two 5-min stories by contributing to them alternatingly one word at a time. The participants were located in different rooms, with audio connection during one story and audiovisual during the other. They were free to select the topic of the story. Although the participants received no instructions regarding the timing of the story building, their word rhythms were highly entrained (øverlineR = 0.70, p < 0.001) even though the rhythms as such were unstable (øverlineR = 0.14 for pooled data). Such high entrainment in the absence of steady word rhythm occurred in every individual story, independently of whether the subjects were connected via audio-only or audiovisual link. The observed entrainment was of similar strength as typical entrainment in finger-tapping tasks where participants are specifically instructed to synchronize their behavior. Thus, speech seems to spontaneously induce strong entrainment between the conversation partners, likely reflecting automatic alignment of their semantic and syntactic processes.

  18. Getting the beat: entrainment of brain activity by musical rhythm and pleasantness.

    PubMed

    Trost, Wiebke; Frühholz, Sascha; Schön, Daniele; Labbé, Carolina; Pichon, Swann; Grandjean, Didier; Vuilleumier, Patrik

    2014-12-01

    Rhythmic entrainment is an important component of emotion induction by music, but brain circuits recruited during spontaneous entrainment of attention by music and the influence of the subjective emotional feelings evoked by music remain still largely unresolved. In this study we used fMRI to test whether the metric structure of music entrains brain activity and how music pleasantness influences such entrainment. Participants listened to piano music while performing a speeded visuomotor detection task in which targets appeared time-locked to either strong or weak beats. Each musical piece was presented in both a consonant/pleasant and dissonant/unpleasant version. Consonant music facilitated target detection and targets presented synchronously with strong beats were detected faster. FMRI showed increased activation of bilateral caudate nucleus when responding on strong beats, whereas consonance enhanced activity in attentional networks. Meter and consonance selectively interacted in the caudate nucleus, with greater meter effects during dissonant than consonant music. These results reveal that the basal ganglia, involved both in emotion and rhythm processing, critically contribute to rhythmic entrainment of subcortical brain circuits by music.

  19. Word-by-word entrainment of speech rhythm during joint story building

    PubMed Central

    Himberg, Tommi; Hirvenkari, Lotta; Mandel, Anne; Hari, Riitta

    2015-01-01

    Movements and behavior synchronize during social interaction at many levels, often unintentionally. During smooth conversation, for example, participants adapt to each others' speech rates. Here we aimed to find out to which extent speakers adapt their turn-taking rhythms during a story-building game. Nine sex-matched dyads of adults (12 males, 6 females) created two 5-min stories by contributing to them alternatingly one word at a time. The participants were located in different rooms, with audio connection during one story and audiovisual during the other. They were free to select the topic of the story. Although the participants received no instructions regarding the timing of the story building, their word rhythms were highly entrained (øverlineR = 0.70, p < 0.001) even though the rhythms as such were unstable (øverlineR = 0.14 for pooled data). Such high entrainment in the absence of steady word rhythm occurred in every individual story, independently of whether the subjects were connected via audio-only or audiovisual link. The observed entrainment was of similar strength as typical entrainment in finger-tapping tasks where participants are specifically instructed to synchronize their behavior. Thus, speech seems to spontaneously induce strong entrainment between the conversation partners, likely reflecting automatic alignment of their semantic and syntactic processes. PMID:26124735

  20. Integration of stripping of fines slurry in a coking and gasification process

    DOEpatents

    DeGeorge, Charles W.

    1980-01-01

    In an integrated fluid coking and gasification process wherein a stream of fluidized solids is passed from a fluidized bed coking zone to a second fluidized bed and wherein entrained solid fines are recovered by a wet scrubbing process and wherein the resulting solids-liquid slurry is stripped to remove acidic gases, the stripped vapors of the stripping zone are sent to the gas cleanup stage of the gasification product gas. The improved stripping integration is particularly useful in the combination coal liquefaction process, fluid coking of bottoms of the coal liquefaction zone and gasification of the product coke.

  1. Predicting bed shear stress and its role in sediment dynamics and restoration potential of the Everglades and other vegetated flow systems

    USGS Publications Warehouse

    Larsen, L.G.; Harvey, J.W.; Crimaldi, J.P.

    2009-01-01

    Entrainment of sediment by flowing water affects topography, habitat suitability, and nutrient cycling in vegetated floodplains and wetlands, impacting ecosystem evolution and the success of restoration projects. Nonetheless, restoration managers lack simple decision-support tools for predicting shear stresses and sediment redistribution potential in different vegetation communities. Using a field-validated numerical model, we developed state-space diagrams that provide these predictions over a range of water-surface slopes, depths, and associated velocities in Everglades ridge and slough vegetation communities. Diminished bed shear stresses and a consequent decrease in bed sediment redistribution are hypothesized causes of a recent reduction in the topographic and vegetation heterogeneity of this ecosystem. Results confirmed the inability of present-day flows to entrain bed sediment. Further, our diagrams showed bed shear stresses to be highly sensitive to emergent vegetation density and water-surface slope but less sensitive to water depth and periphyton or floating vegetation abundance. These findings suggested that instituting a pulsing flow regime could be the most effective means to restore sediment redistribution to the Everglades. However, pulsing flows will not be sufficient to erode sediment from sloughs with abundant spikerush, unless spikerush density first decreases by natural or managed processes. Our methods provide a novel tool for identifying restoration parameters and performance measures in many types of vegetated aquatic environments where sediment erosion and deposition are involved.

  2. The controls and consequences of substrate entrainment by pyroclastic density currents at Mount St Helens, Washington (USA)

    NASA Astrophysics Data System (ADS)

    Pollock, N. M.; Brand, B. D.; Roche, O.

    2016-10-01

    Evidence in the deposits from the May 18, 1980 eruption at Mount St Helens demonstrates that pyroclastic density currents (PDCs) produced during the afternoon of the eruption became intermittently erosive. Using detailed componentry and granulometry we constrain the sources for lithic blocks in the deposits and identify deposits from PDCs that became locally erosive. The componentry of the lithics in the fall deposits is used as a proxy for vent erosion and assumed to represent the starting componentry for PDCs prior to entrainment from any other source. We find little evidence in the PDC deposits nearest to the base of the volcano for entrainment from the steep flanks; however, significant evidence indicates that PDCs eroded into the debris avalanche hummocks, suggesting that entrainment is favored as PDCs interact with highly irregular topography. Evidence for locally entrained material downstream from debris avalanche hummocks decreases with height in the outcrop, suggesting that less entrainment occurs as local relief decreases and upstream topography is buried. The prevalence of lithofacies containing locally entrained material at the base of unit contacts and only 10s of meters downstream from debris avalanche hummocks suggests that the majority of entrainment occurs at or near the head of the current. Occasionally, entrained material is located high above unit contacts and deposited well after the initial head of the current is inferred to have passed, indicating that entrainment can occur during periods of non-deposition either from the semi-sustained body of the current or from a pulsating current. Additionally, self-channelization of PDCs, either by levee deposition or scouring into earlier PDC deposits, occurs independently of interaction with topographic obstacles and can affect carrying capacity and runout distance. While we begin to explore the mechanisms and effects of erosion on current dynamics, additional laboratory and numerical studies are

  3. Fluidized bed coal desulfurization

    NASA Technical Reports Server (NTRS)

    Ravindram, M.

    1983-01-01

    Laboratory scale experiments were conducted on two high volatile bituminous coals in a bench scale batch fluidized bed reactor. Chemical pretreatment and posttreatment of coals were tried as a means of enhancing desulfurization. Sequential chlorination and dechlorination cum hydrodesulfurization under modest conditions relative to the water slurry process were found to result in substantial sulfur reductions of about 80%. Sulfur forms as well as proximate and ultimate analyses of the processed coals are included. These studies indicate that a fluidized bed reactor process has considerable potential for being developed into a simple and economic process for coal desulfurization.

  4. Relationship between Entrainment and Static Pressure Field on 2-D Jets.

    NASA Astrophysics Data System (ADS)

    Kimura, M.; Ono, K.; Saima, A.

    1996-11-01

    It is well know that entrainment carried out in wakes and jets. This experimental study aimes at investigation the relationship between the entrainment and the pressure field in 2-D jet. The 2-D jet was generated by 2-D rectangular wind tunnel. The velocity and prressure fields were observed in order to investigate the free shear layer of jet. These value were measured by the x type hot-wire anemometer, LDV and the newly developed static pressure probe. Jet diffusion process is visualized by smoke wire method. The result of the experiment was that the static pressure fluctuated intensively, and was negative mean value because of the velocity intermittence in the free shear layer of the 2-D jet. It seems reasonable to suppose that entrainment occurs owing to the negative static pressure by the eddy motion and large scale convection in the free shear layer.

  5. Conceptual process design and techno-economic assessment of ex situ catalytic fast pyrolysis of biomass: A fixed bed reactor implementation scenario for future feasibility

    DOE PAGESBeta

    Dutta, Abhijit; Schaidle, Joshua A.; Humbird, David; Baddour, Frederick G.; Sahir, Asad

    2015-10-06

    Ex situ catalytic fast pyrolysis of biomass is a promising route for the production of fungible liquid biofuels. There is significant ongoing research on the design and development of catalysts for this process. However, there are a limited number of studies investigating process configurations and their effects on biorefinery economics. Herein we present a conceptual process design with techno-economic assessment; it includes the production of upgraded bio-oil via fixed bed ex situ catalytic fast pyrolysis followed by final hydroprocessing to hydrocarbon fuel blendstocks. This study builds upon previous work using fluidized bed systems, as detailed in a recent design reportmore » led by the National Renewable Energy Laboratory (NREL/TP-5100-62455); overall yields are assumed to be similar, and are based on enabling future feasibility. Assuming similar yields provides a basis for easy comparison and for studying the impacts of areas of focus in this study, namely, fixed bed reactor configurations and their catalyst development requirements, and the impacts of an inline hot gas filter. A comparison with the fluidized bed system shows that there is potential for higher capital costs and lower catalyst costs in the fixed bed system, leading to comparable overall costs. The key catalyst requirement is to enable the effective transformation of highly oxygenated biomass into hydrocarbons products with properties suitable for blending into current fuels. Potential catalyst materials are discussed, along with their suitability for deoxygenation, hydrogenation and C–C coupling chemistry. This chemistry is necessary during pyrolysis vapor upgrading for improved bio-oil quality, which enables efficient downstream hydroprocessing; C–C coupling helps increase the proportion of diesel/jet fuel range product. One potential benefit of fixed bed upgrading over fluidized bed upgrading is catalyst flexibility, providing greater control over chemistry and product composition

  6. Conceptual process design and techno-economic assessment of ex situ catalytic fast pyrolysis of biomass: A fixed bed reactor implementation scenario for future feasibility

    SciTech Connect

    Dutta, Abhijit; Schaidle, Joshua A.; Humbird, David; Baddour, Frederick G.; Sahir, Asad

    2015-10-06

    Ex situ catalytic fast pyrolysis of biomass is a promising route for the production of fungible liquid biofuels. There is significant ongoing research on the design and development of catalysts for this process. However, there are a limited number of studies investigating process configurations and their effects on biorefinery economics. Herein we present a conceptual process design with techno-economic assessment; it includes the production of upgraded bio-oil via fixed bed ex situ catalytic fast pyrolysis followed by final hydroprocessing to hydrocarbon fuel blendstocks. This study builds upon previous work using fluidized bed systems, as detailed in a recent design report led by the National Renewable Energy Laboratory (NREL/TP-5100-62455); overall yields are assumed to be similar, and are based on enabling future feasibility. Assuming similar yields provides a basis for easy comparison and for studying the impacts of areas of focus in this study, namely, fixed bed reactor configurations and their catalyst development requirements, and the impacts of an inline hot gas filter. A comparison with the fluidized bed system shows that there is potential for higher capital costs and lower catalyst costs in the fixed bed system, leading to comparable overall costs. The key catalyst requirement is to enable the effective transformation of highly oxygenated biomass into hydrocarbons products with properties suitable for blending into current fuels. Potential catalyst materials are discussed, along with their suitability for deoxygenation, hydrogenation and C–C coupling chemistry. This chemistry is necessary during pyrolysis vapor upgrading for improved bio-oil quality, which enables efficient downstream hydroprocessing; C–C coupling helps increase the proportion of diesel/jet fuel range product. One potential benefit of fixed bed upgrading over fluidized bed upgrading is catalyst flexibility, providing greater control over chemistry and product composition. Since this

  7. On-line ultrasonic gas entrainment monitor

    DOEpatents

    Day, Clifford K.; Pedersen, Herbert N.

    1978-01-01

    Apparatus employing ultrasonic energy for detecting and measuring the quantity of gas bubbles present in liquids being transported through pipes. An ultrasonic transducer is positioned along the longitudinal axis of a fluid duct, oriented to transmit acoustic energy radially of the duct around the circumference of the enclosure walls. The back-reflected energy is received centrally of the duct and interpreted as a measure of gas entrainment. One specific embodiment employs a conical reflector to direct the transmitted acoustic energy radially of the duct and redirect the reflected energy back to the transducer for reception. A modified embodiment employs a cylindrical ultrasonic transducer for this purpose.

  8. Endogenous Delta/Theta Sound-Brain Phase Entrainment Accelerates the Buildup of Auditory Streaming.

    PubMed

    Riecke, Lars; Sack, Alexander T; Schroeder, Charles E

    2015-12-21

    In many natural listening situations, meaningful sounds (e.g., speech) fluctuate in slow rhythms among other sounds. When a slow rhythmic auditory stream is selectively attended, endogenous delta (1‒4 Hz) oscillations in auditory cortex may shift their timing so that higher-excitability neuronal phases become aligned with salient events in that stream [1, 2]. As a consequence of this stream-brain phase entrainment [3], these events are processed and perceived more readily than temporally non-overlapping events [4-11], essentially enhancing the neural segregation between the attended stream and temporally noncoherent streams [12]. Stream-brain phase entrainment is robust to acoustic interference [13-20] provided that target stream-evoked rhythmic activity can be segregated from noncoherent activity evoked by other sounds [21], a process that usually builds up over time [22-27]. However, it has remained unclear whether stream-brain phase entrainment functionally contributes to this buildup of rhythmic streams or whether it is merely an epiphenomenon of it. Here, we addressed this issue directly by experimentally manipulating endogenous stream-brain phase entrainment in human auditory cortex with non-invasive transcranial alternating current stimulation (TACS) [28-30]. We assessed the consequences of these manipulations on the perceptual buildup of the target stream (the time required to recognize its presence in a noisy background), using behavioral measures in 20 healthy listeners performing a naturalistic listening task. Experimentally induced cyclic 4-Hz variations in stream-brain phase entrainment reliably caused a cyclic 4-Hz pattern in perceptual buildup time. Our findings demonstrate that strong endogenous delta/theta stream-brain phase entrainment accelerates the perceptual emergence of task-relevant rhythmic streams in noisy environments. PMID:26628008

  9. Endogenous Delta/Theta Sound-Brain Phase Entrainment Accelerates the Buildup of Auditory Streaming.

    PubMed

    Riecke, Lars; Sack, Alexander T; Schroeder, Charles E

    2015-12-21

    In many natural listening situations, meaningful sounds (e.g., speech) fluctuate in slow rhythms among other sounds. When a slow rhythmic auditory stream is selectively attended, endogenous delta (1‒4 Hz) oscillations in auditory cortex may shift their timing so that higher-excitability neuronal phases become aligned with salient events in that stream [1, 2]. As a consequence of this stream-brain phase entrainment [3], these events are processed and perceived more readily than temporally non-overlapping events [4-11], essentially enhancing the neural segregation between the attended stream and temporally noncoherent streams [12]. Stream-brain phase entrainment is robust to acoustic interference [13-20] provided that target stream-evoked rhythmic activity can be segregated from noncoherent activity evoked by other sounds [21], a process that usually builds up over time [22-27]. However, it has remained unclear whether stream-brain phase entrainment functionally contributes to this buildup of rhythmic streams or whether it is merely an epiphenomenon of it. Here, we addressed this issue directly by experimentally manipulating endogenous stream-brain phase entrainment in human auditory cortex with non-invasive transcranial alternating current stimulation (TACS) [28-30]. We assessed the consequences of these manipulations on the perceptual buildup of the target stream (the time required to recognize its presence in a noisy background), using behavioral measures in 20 healthy listeners performing a naturalistic listening task. Experimentally induced cyclic 4-Hz variations in stream-brain phase entrainment reliably caused a cyclic 4-Hz pattern in perceptual buildup time. Our findings demonstrate that strong endogenous delta/theta stream-brain phase entrainment accelerates the perceptual emergence of task-relevant rhythmic streams in noisy environments.

  10. Entrainment to periodic initiation and transition rates in a computational model for gene translation.

    PubMed

    Margaliot, Michael; Sontag, Eduardo D; Tuller, Tamir

    2014-01-01

    Periodic oscillations play an important role in many biomedical systems. Proper functioning of biological systems that respond to periodic signals requires the ability to synchronize with the periodic excitation. For example, the sleep/wake cycle is a manifestation of an internal timing system that synchronizes to the solar day. In the terminology of systems theory, the biological system must entrain or phase-lock to the periodic excitation. Entrainment is also important in synthetic biology. For example, connecting several artificial biological systems that entrain to a common clock may lead to a well-functioning modular system. The cell-cycle is a periodic program that regulates DNA synthesis and cell division. Recent biological studies suggest that cell-cycle related genes entrain to this periodic program at the gene translation level, leading to periodically-varying protein levels of these genes. The ribosome flow model (RFM) is a deterministic model obtained via a mean-field approximation of a stochastic model from statistical physics that has been used to model numerous processes including ribosome flow along the mRNA. Here we analyze the RFM under the assumption that the initiation and/or transition rates vary periodically with a common period T. We show that the ribosome distribution profile in the RFM entrains to this periodic excitation. In particular, the protein synthesis pattern converges to a unique periodic solution with period T. To the best of our knowledge, this is the first proof of entrainment in a mathematical model for translation that encapsulates aspects such as initiation and termination rates, ribosomal movement and interactions, and non-homogeneous elongation speeds along the mRNA. Our results support the conjecture that periodic oscillations in tRNA levels and other factors related to the translation process can induce periodic oscillations in protein levels, and may suggest a new approach for re-engineering genetic systems to obtain a

  11. Update on performance tests from the COBRA Process, a combined SO{sub 2} and NO{sub x} removal system[Copper Oxide Bed Regenerable Adsorber

    SciTech Connect

    Breault, R.W.; Litka, T.

    1999-07-01

    The Low Emission Boiler System (LEBS) Program of the US Department of Energy (DOE) is developing advanced power systems to accelerate the commercialization of affordable, highly efficient, and low-emission pulverized coal-fueled electric generating technologies. DB Riley Inc.'s concept for LEBS includes a dry, regenerable flue gas desulfurization and denitrification process. The COBRA (Copper Oxide Bed Regenerable Adsorber) Process can efficiently remove sulfur dioxide (SO{sub 2}) and sulfur trioxide (SO{sub 3}) and reduce nitrogen oxides (NO{sub x}) from flue gas with no solid or liquid byproducts and at a competitive cost. The sulfur laden flue gas is contacted with copper oxide impregnated alumina substrate in a cross flow moving bed reactor operating at 700 F. Sulfur dioxide reacts with the copper to form copper sulfate and the copper oxide/copper sulfate bed acts as a selective catalyst for NO{sub x} reduction. The sulfated sorbent is transported from the bottom of the moving bed reactors to the regenerator vessels where methane is used to reduce the copper sulfate to copper and SO{sub 2}. The concentrated SO{sub 2} stream resulting from regeneration may be oxidized to SO{sub 3} and condensed to sulfuric acid or can be converted to elemental sulfur in a Claus Plant or scrubbed with ammonia to form an ammonium sulfate. This paper will present the results of performance testing conducted on a 1 MW Pilot Scale Facility located at the Illinois Coal Development Park. This facility was designed and built to demonstrate at a reasonable scale the component configurations to be utilized in a full-scale system and to verify and optimize the operation of the integrated system. The ability of laboratory tests, when combined with a model of the moving bed adsorber, to predict the performance of the pilot system will be shown.

  12. Remediation of acid mine drainage at the friendship hill national historic site with a pulsed limestone bed process

    USGS Publications Warehouse

    Sibrell, P.L.; Watten, B.; Boone, T.; ,

    2003-01-01

    A new process utilizing pulsed fluidized limestone beds was tested for the remediation of acid mine drainage at the Friendship Hill National Historic Site, in southwestern Pennsylvania. A 230 liter-per-minute treatment system was constructed and operated over a fourteen-month period from June 2000 through September 2001. Over this period of time, 50,000 metric tons of limestone were used to treat 50 million liters of water. The influent water pH was 2.5 and acidity was 1000 mg/L as CaCO3. Despite the high potential for armoring at the site, effluent pH during normal plant operation ranged from 5.7 to 7.8 and averaged 6.8. As a result of the high influent acidity, sufficient CO2 was generated and recycled to provide a net alkaline discharge with about 50 mg/L as CaCO3 alkalinity. Additions of commercial CO2 increased effluent alkalinity to as high as 300 mg/L, and could be a useful process management tool for transient high flows or acidities. Metal removal rates were 95% for aluminum (60 mg/L in influent), 50 to 90% for iron (Fe), depending on the ratio of ferrous to ferric iron, which varied seasonally (200 mg/L in influent), and <10% of manganese (Mn) (10 mg/L in influent). Ferrous iron and Mn removal was incomplete because of the high pH required for precipitation of these species. Iron removal could be improved by increased aeration following neutralization, and Mn removal could be effected by a post treatment passive settling/oxidation pond. Metal hydroxide sludges were settled in settling tanks, and then hauled from the site for aesthetic purposes. Over 450 metric tons of sludge were removed from the water over the life of the project. The dried sludge was tested by the Toxicity Characteristics Leaching Protocol (TCLP) and was found to be non-hazardous. Treatment costs were $43,000 per year and $1.08 per m 3, but could be decreased to $22,000 and $0.51 per m3 by decreasing labor use and by onsite sludge handling. These results confirm the utility of the new

  13. The ecology of entrainment: Foundations of coordinated rhythmic movement

    PubMed Central

    Phillips-Silver, Jessica; Aktipis, C. Athena; Bryant, Gregory A.

    2011-01-01

    Entrainment has been studied in a variety of contexts including music perception, dance, verbal communication and motor coordination more generally. Here we seek to provide a unifying framework that incorporates the key aspects of entrainment as it has been studied in these varying domains. We propose that there are a number of types of entrainment that build upon pre-existing adaptations that allow organisms to perceive stimuli as rhythmic, to produce periodic stimuli, and to integrate the two using sensory feedback. We suggest that social entrainment is a special case of spatiotemporal coordination where the rhythmic signal originates from another individual. We use this framework to understand the function and evolutionary basis for coordinated rhythmic movement and to explore questions about the nature of entrainment in music and dance. The framework of entrainment presented here has a number of implications for the vocal learning hypothesis and other proposals for the evolution of coordinated rhythmic behavior across an array of species. PMID:21776183

  14. The Influence of Relative Submergence on the Near-bed Flow Field: Implications for Bed-load Transport

    NASA Astrophysics Data System (ADS)

    Cooper, J.; Tait, S.; Marion, A.

    2005-12-01

    Bed-load is governed by interdependent mechanisms, the most significant being the interaction between bed roughness, surface layer composition and near-bed flow. Despite this, practically all transport rate equations are described as a function of average bed shear stress. Some workers have examined the role of turbulence in sediment transport (Nelson et al. 1995) but have not explored the potential significance of spatial variations in the near-bed flow field. This is unfortunate considering evidence showing that transport is spatially heterogeneous and could be linked to the spatial nature of the near-bed flow (Drake et al., 1988). An understanding is needed of both the temporal and spatial variability in the near-bed flow field. This paper presents detailed spatial velocity measurements of the near-bed flow field over a gravel-bed, obtained using Particle Image Velocimetry. These data have been collected in a laboratory flume under two regimes: (i) tests with one bed slope and different flow depths; and (ii) tests with a combination of flow depths and slopes at the same average bed shear stress. Results indicate spatial variation in the streamwise velocities of up to 45 per cent from the double-averaged velocity (averaged in both time and space). Under both regimes, as the depth increased, spatial variability in the flow field increased. The probability distributions of near-bed streamwise velocities became progressively more skewed towards the higher velocities. This change was more noticeable under regime (i). This has been combined with data from earlier tests in which the near-bed velocity close to an entraining grain was measured using a PIV/image analysis system (Chegini et al, 2002). This along with data on the shape of the probability density function of velocities capable of entraining individual grains derived from a discrete-particle model (Heald et al., 2004) has been used to estimate the distribution of local velocities required for grain motion in

  15. Wetlands and Aquatic Processes: A Bed Sediment Sampler for Precise Depth Profiling of Contaminant Concentrations in Aquatic Environments

    SciTech Connect

    Quinn, Nigel W. T.; Clyde, John R.

    1997-11-01

    A bed sediment and detritus sampler has been dec eloped for use in aquatic environments, such as in canals, rivers or lakes, for determining precise depth profiles of contaminants, The device is superior to currently available commercial push-tube and piston samplers in its simplicity, ease of use and its ability to retrieve and extrude sample cores. The sampler has been used with success during the past 12 mo to determine a profile of bed sediment Se concentrations within an earth-lined canal, alternatively used for conveyance of agricultural drainage and wetland water supply.

  16. CONTINUOUS PROCESS FOR PREPARING URANIUM HEXAFLUORIDE FROM URANIUM TETRAFLUORIDE AND OXYGEN

    DOEpatents

    Adams, J.B.; Bresee, J.C.; Ferris, L.M.

    1961-11-21

    A process for preparing UF/sub 6/ by reacting UF/sub 4/ and oxygen is described. The UF/sub 4/ and oxygen are continuously introduced into a fluidized bed of UO/sub 2/F/sub 2/ at a temperature of 600 to 900 deg C. The concentration of UF/sub 4/ in the bed is maintained below 25 weight per cent in order to avoid sintering and intermediate compound formation. By-product U0/sub 2/F/sub 2/ is continuously removed from the top of the bed recycled. In an alternative embodiment heat is supplied to the reaction bed by burning carbon monoxide in the bed. The product UF/sub 6/ is filtered to remove entrained particles and is recovered in cold traps and chemical traps. (AEC)

  17. An observational study of entrainment rate in deep convection

    SciTech Connect

    Guo, Xiaohao; Lu, Chunsong; Zhao, Tianliang; Zhang, Guang Jun; Liu, Yangang

    2015-09-22

    This study estimates entrainment rate and investigates its relationships with cloud properties in 156 deep convective clouds based on in-situ aircraft observations during the TOGA-COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment) field campaign over the western Pacific. To the authors’ knowledge, this is the first study on the probability density function of entrainment rate, the relationships between entrainment rate and cloud microphysics, and the effects of dry air sources on the calculated entrainment rate in deep convection from an observational perspective. Results show that the probability density function of entrainment rate can be well fitted by lognormal, gamma or Weibull distribution, with coefficients of determination being 0.82, 0.85 and 0.80, respectively. Entrainment tends to reduce temperature, water vapor content and moist static energy in cloud due to evaporative cooling and dilution. Inspection of the relationships between entrainment rate and microphysical properties reveals a negative correlation between volume-mean radius and entrainment rate, suggesting the potential dominance of homogeneous mechanism in the clouds examined. The entrainment rate and environmental water vapor content show similar tendencies of variation with the distance of the assumed environmental air to the cloud edges. Their variation tendencies are non-monotonic due to the relatively short distance between adjacent clouds.

  18. An observational study of entrainment rate in deep convection

    DOE PAGESBeta

    Guo, Xiaohao; Lu, Chunsong; Zhao, Tianliang; Zhang, Guang Jun; Liu, Yangang

    2015-09-22

    This study estimates entrainment rate and investigates its relationships with cloud properties in 156 deep convective clouds based on in-situ aircraft observations during the TOGA-COARE (Tropical Ocean Global Atmosphere Coupled Ocean Atmosphere Response Experiment) field campaign over the western Pacific. To the authors’ knowledge, this is the first study on the probability density function of entrainment rate, the relationships between entrainment rate and cloud microphysics, and the effects of dry air sources on the calculated entrainment rate in deep convection from an observational perspective. Results show that the probability density function of entrainment rate can be well fitted by lognormal,more » gamma or Weibull distribution, with coefficients of determination being 0.82, 0.85 and 0.80, respectively. Entrainment tends to reduce temperature, water vapor content and moist static energy in cloud due to evaporative cooling and dilution. Inspection of the relationships between entrainment rate and microphysical properties reveals a negative correlation between volume-mean radius and entrainment rate, suggesting the potential dominance of homogeneous mechanism in the clouds examined. The entrainment rate and environmental water vapor content show similar tendencies of variation with the distance of the assumed environmental air to the cloud edges. Their variation tendencies are non-monotonic due to the relatively short distance between adjacent clouds.« less

  19. The effect of entrainment on starting vortices

    NASA Astrophysics Data System (ADS)

    Rosi, Giuseppe; Rival, David

    2015-11-01

    Recent work shows that vortex detachment behind accelerating plates coincides with when streamlines enclosing the starting vortex (SV) form a full saddle. In the case of a linearly accelerating plate, it can be shown that vorticity-containing mass, and thus the SV's development scale with only dimensionless towed distance, while the SV's circulation scales with the acceleration rate. This results in shear-layer instabilities whose structure is Reynold-number independent, but whose strength scale with Reynolds number. It is hypothesized that the increased strength of the instabilities promotes entrainment, which causes the formation of the full saddle and thereby detachment to occur at an earlier dimensionless towed distance. To test this hypothesis, a circular plate is linearly accelerated from rest to pinch-off with chord-based Reynolds numbers of 103, 104, and 105 at the midpoint of the motion. Planar PIV data is acquired, from which FTLE and enstrophy fields are calculated. Vortex detachment is identified from the dynamics of the FTLE saddles, while the enstrophy fields are used to calculate both the vorticity-containing mass entering from the shear layer and the mass entrained from the quiescent surroundings.

  20. Stochastic entrainment of a stochastic oscillator.

    PubMed

    Wang, Guanyu; Peskin, Charles S

    2015-01-01

    In this work, we consider a stochastic oscillator described by a discrete-state continuous-time Markov chain, in which the states are arranged in a circle, and there is a constant probability per unit time of jumping from one state to the next in a specified direction around the circle. At each of a sequence of equally spaced times, the oscillator has a specified probability of being reset to a particular state. The focus of this work is the entrainment of the oscillator by this periodic but stochastic stimulus. We consider a distinguished limit, in which (i) the number of states of the oscillator approaches infinity, as does the probability per unit time of jumping from one state to the next, so that the natural mean period of the oscillator remains constant, (ii) the resetting probability approaches zero, and (iii) the period of the resetting signal approaches a multiple, by a ratio of small integers, of the natural mean period of the oscillator. In this distinguished limit, we use analytic and numerical methods to study the extent to which entrainment occurs.

  1. Application of the biological granular activated carbon fluidized bed reactor process for gas industry waste treatment. Topical report, January 1991-December 1992

    SciTech Connect

    Wagner, D.; Sunday, A.; Hickey, R.F.

    1993-06-01

    The research and development work is focused on evaluating the applicability of using the biological granular activated carbon-fluidized bed reactor (GAC-FBR) for helping to solve gas industry waste treatment needs. The specific goals are to use and modify the GAC-FBR process, as needed, for (1) remediation of groundwater contaminated by gas industry operations, and (2) treatment of gas production and exploration waters.

  2. SUPERFUND TREATABILITY CLEARINGHOUSE: BDAT TREATABILITY DATA FOR SOILS, SLUDGES AND DEBRIS FROM THE CIRCULATING BED COMBUSTION (CBC) PROCESS

    EPA Science Inventory

    The two papers provide a general overview of the Ogden circulating bed combustion and summary data of both PCB laden soils for EPA-TSCA and a test on RCRA liquid organic wastes for the California Air Resources Board (CARB). This abstract will discuss the results of the PCB...

  3. On Nonstationary Processes of Heat Transfer in a Bed of Finely Dispersed Capsules in the Presence of Phase Transition

    NASA Astrophysics Data System (ADS)

    Teplitskii, Yu. S.; Roslik, A. R.

    2015-11-01

    Within the framework of the two-temperature model, the authors have investigated the dynamics of charging and discharging of a bed of finely dispersed spherical capsules. Generalized dependences have been obtained for calculating the times of charging and discharging of a heat accumulator.

  4. Comparison of entrainment rates from a tank experiment with results using the one-dimensional turbulence model.

    SciTech Connect

    Kerstein, Alan R.; Sayler, B. J.; Wunsch, S.; Schmidt, H.; Nedelec, R.

    2010-05-01

    Recent work suggests that cloud effects remain one of the largest sources of uncertainty in model-based estimates of climate sensitivity. In particular, the entrainment rate in stratocumulus-topped mixed layers needs better models. More than thirty years ago a clever laboratory experiment was conducted by McEwan and Paltridge to examine an analog of the entrainment process at the top of stratiform clouds. Sayler and Breidenthal extended this pioneering work and determined the effect of the Richardson number on the dimensionless entrainment rate. The experiments gave hints that the interaction between molecular effects and the one-sided turbulence seems to be crucial for understanding entrainment. From the numerical point of view large-eddy simulation (LES) does not allow explicitly resolving all the fine scale processes at the entrainment interface. Direct numerical simulation (DNS) is limited due to the Reynolds number and is not the tool of choice for parameter studies. Therefore it is useful to investigate new modeling strategies, such as stochastic turbulence models which allow sufficient resolution at least in one dimension while having acceptable run times. We will present results of the One-Dimensional Turbulence stochastic simulation model applied to the experimental setup of Sayler and Breidenthal. The results on radiatively induced entrainment follow quite well the scaling of the entrainment rate with the Richardson number that was experimentally found for a set of trials. Moreover, we investigate the influence of molecular effects, the fluids optical properties, and the artifact of parasitic turbulence experimentally observed in the laminar layer. In the simulations the parameters are varied systematically for even larger ranges than in the experiment. Based on the obtained results a more complex parameterization of the entrainment rate than currently discussed in the literature seems to be necessary.

  5. Design of a fixed-bed ion-exchange process for the treatment of rinse waters generated in the galvanization process using Laminaria hyperborea as natural cation exchanger.

    PubMed

    Mazur, Luciana P; Pozdniakova, Tatiana A; Mayer, Diego A; Boaventura, Rui A R; Vilar, Vítor J P

    2016-03-01

    In this study, the removal of zinc from galvanization wastewaters was performed in a fixed bed column packed with brown macro-algae Laminaria hyperborea, acting as a natural cation exchanger (resin). The rinse wastewater presents a zinc concentration between 9 and 22 mg/L, a high concentration of light metals (mainly Na and Ca), a high conductivity (0.5-1.5 mS/cm) and a low organic content (DOC = 7-15 mg C/L). The zinc speciation diagram showed that approximately 80% of zinc is in the form of Zn(2+) and ≅20% as ZnSO4, considering the effluent matrix. From all operational conditions tested for zinc uptake (17 < bed height<27 cm, 4.5 < flow rate<18.2 BV/h, 0.8 < particle equivalent diameter<2.0 mm), the highest useful capacity (7.1 mg Zn/g algae) was obtained for D/dp = 31, L/D = 11, 9.1 BV/h, τ = 6.4 min, corresponding to a service capacity of 124 BV (endpoint of 2 mg Zn/L). Elution was faster and near to 100% effective using 10 BV of HCl (1 M, 3.0%, 363 g HCl/L of resin), for flow rates higher than 4.5 BV/h. Calcium chloride solution (0.1 M) was selected as the best regenerant, allowing the reuse of the natural resin for more than 3 saturation/elution/regeneration cycles. The best operation conditions were scaled-up and tested in a pre-pilot plant. The scale-up design of the cation exchange process was proposed for the treatment of 2.4 m(3)/day of galvanization wastewater, resulting in an estimated reactants cost of 2.44 €/m(3).

  6. Design of a fixed-bed ion-exchange process for the treatment of rinse waters generated in the galvanization process using Laminaria hyperborea as natural cation exchanger.

    PubMed

    Mazur, Luciana P; Pozdniakova, Tatiana A; Mayer, Diego A; Boaventura, Rui A R; Vilar, Vítor J P

    2016-03-01

    In this study, the removal of zinc from galvanization wastewaters was performed in a fixed bed column packed with brown macro-algae Laminaria hyperborea, acting as a natural cation exchanger (resin). The rinse wastewater presents a zinc concentration between 9 and 22 mg/L, a high concentration of light metals (mainly Na and Ca), a high conductivity (0.5-1.5 mS/cm) and a low organic content (DOC = 7-15 mg C/L). The zinc speciation diagram showed that approximately 80% of zinc is in the form of Zn(2+) and ≅20% as ZnSO4, considering the effluent matrix. From all operational conditions tested for zinc uptake (17 < bed height<27 cm, 4.5 < flow rate<18.2 BV/h, 0.8 < particle equivalent diameter<2.0 mm), the highest useful capacity (7.1 mg Zn/g algae) was obtained for D/dp = 31, L/D = 11, 9.1 BV/h, τ = 6.4 min, corresponding to a service capacity of 124 BV (endpoint of 2 mg Zn/L). Elution was faster and near to 100% effective using 10 BV of HCl (1 M, 3.0%, 363 g HCl/L of resin), for flow rates higher than 4.5 BV/h. Calcium chloride solution (0.1 M) was selected as the best regenerant, allowing the reuse of the natural resin for more than 3 saturation/elution/regeneration cycles. The best operation conditions were scaled-up and tested in a pre-pilot plant. The scale-up design of the cation exchange process was proposed for the treatment of 2.4 m(3)/day of galvanization wastewater, resulting in an estimated reactants cost of 2.44 €/m(3). PMID:26766159

  7. Turbulent mixing and entrainment in a gravity current

    SciTech Connect

    Ecke, Robert E; Odier, Philippe; Chen, Jun

    2010-01-01

    We present an experimental study of the mixing processes in a gravity current. The turbulent transport of momentum and buoyancy can be described in a very direct and compact form by a Prandtl mixing length model: the turbulent vertical fluxes of momentum and buoyancy are found to scale quadratically with the vertical mean gradients of velocity and density. The scaling coefficient is the square of the mixing lenth, approximately constant over the mixing zone of the stratified shear layer. We show how, in different flow configurations, this length can be related to the shear length of the flow ({var_epsilon}/{partial_derivative}{sub z}u{sup 3}){sup 1/2}. We also study the fluctuations of the momentum and density turbulent fluxes, showing how they relate to the mixing phenomena, and to the entrainment/detrainment balance.

  8. Phase-selective entrainment of nonlinear oscillator ensembles

    NASA Astrophysics Data System (ADS)

    Zlotnik, Anatoly; Nagao, Raphael; Kiss, István Z.; Li-Shin, Jr.

    2016-03-01

    The ability to organize and finely manipulate the hierarchy and timing of dynamic processes is important for understanding and influencing brain functions, sleep and metabolic cycles, and many other natural phenomena. However, establishing spatiotemporal structures in biological oscillator ensembles is a challenging task that requires controlling large collections of complex nonlinear dynamical units. In this report, we present a method to design entrainment signals that create stable phase patterns in ensembles of heterogeneous nonlinear oscillators without using state feedback information. We demonstrate the approach using experiments with electrochemical reactions on multielectrode arrays, in which we selectively assign ensemble subgroups into spatiotemporal patterns with multiple phase clusters. The experimentally confirmed mechanism elucidates the connection between the phases and natural frequencies of a collection of dynamical elements, the spatial and temporal information that is encoded within this ensemble, and how external signals can be used to retrieve this information.

  9. Entrainment of Human Alpha Oscillations Selectively Enhances Visual Conjunction Search.

    PubMed

    Müller, Notger G; Vellage, Anne-Katrin; Heinze, Hans-Jochen; Zaehle, Tino

    2015-01-01

    The functional role of the alpha-rhythm which dominates the human electroencephalogram (EEG) is unclear. It has been related to visual processing, attentional selection and object coherence, respectively. Here we tested the interaction of alpha oscillations of the human brain with visual search tasks that differed in their attentional demands (pre-attentive vs. attentive) and also in the necessity to establish object coherence (conjunction vs. single feature). Between pre- and post-assessment elderly subjects received 20 min/d of repetitive transcranial alternating current stimulation (tACS) over the occipital cortex adjusted to their individual alpha frequency over five consecutive days. Compared to sham the entrained alpha oscillations led to a selective, set size independent improvement in the conjunction search task performance but not in the easy or in the hard feature search task. These findings suggest that cortical alpha oscillations play a specific role in establishing object coherence through suppression of distracting objects. PMID:26606255

  10. Phase-selective entrainment of nonlinear oscillator ensembles

    PubMed Central

    Zlotnik, Anatoly; Nagao, Raphael; Kiss, István Z.; Li, Jr-Shin

    2016-01-01

    The ability to organize and finely manipulate the hierarchy and timing of dynamic processes is important for understanding and influencing brain functions, sleep and metabolic cycles, and many other natural phenomena. However, establishing spatiotemporal structures in biological oscillator ensembles is a challenging task that requires controlling large collections of complex nonlinear dynamical units. In this report, we present a method to design entrainment signals that create stable phase patterns in ensembles of heterogeneous nonlinear oscillators without using state feedback information. We demonstrate the approach using experiments with electrochemical reactions on multielectrode arrays, in which we selectively assign ensemble subgroups into spatiotemporal patterns with multiple phase clusters. The experimentally confirmed mechanism elucidates the connection between the phases and natural frequencies of a collection of dynamical elements, the spatial and temporal information that is encoded within this ensemble, and how external signals can be used to retrieve this information. PMID:26988313

  11. Entrainment of Human Alpha Oscillations Selectively Enhances Visual Conjunction Search

    PubMed Central

    Müller, Notger G.; Vellage, Anne-Katrin; Heinze, Hans-Jochen; Zaehle, Tino

    2015-01-01

    The functional role of the alpha-rhythm which dominates the human electroencephalogram (EEG) is unclear. It has been related to visual processing, attentional selection and object coherence, respectively. Here we tested the interaction of alpha oscillations of the human brain with visual search tasks that differed in their attentional demands (pre-attentive vs. attentive) and also in the necessity to establish object coherence (conjunction vs. single feature). Between pre- and post-assessment elderly subjects received 20 min/d of repetitive transcranial alternating current stimulation (tACS) over the occipital cortex adjusted to their individual alpha frequency over five consecutive days. Compared to sham the entrained alpha oscillations led to a selective, set size independent improvement in the conjunction search task performance but not in the easy or in the hard feature search task. These findings suggest that cortical alpha oscillations play a specific role in establishing object coherence through suppression of distracting objects. PMID:26606255

  12. Phase-selective entrainment of nonlinear oscillator ensembles.

    PubMed

    Zlotnik, Anatoly; Nagao, Raphael; Kiss, István Z; Li, Jr-Shin

    2016-01-01

    The ability to organize and finely manipulate the hierarchy and timing of dynamic processes is important for understanding and influencing brain functions, sleep and metabolic cycles, and many other natural phenomena. However, establishing spatiotemporal structures in biological oscillator ensembles is a challenging task that requires controlling large collections of complex nonlinear dynamical units. In this report, we present a method to design entrainment signals that create stable phase patterns in ensembles of heterogeneous nonlinear oscillators without using state feedback information. We demonstrate the approach using experiments with electrochemical reactions on multielectrode arrays, in which we selectively assign ensemble subgroups into spatiotemporal patterns with multiple phase clusters. The experimentally confirmed mechanism elucidates the connection between the phases and natural frequencies of a collection of dynamical elements, the spatial and temporal information that is encoded within this ensemble, and how external signals can be used to retrieve this information. PMID:26988313

  13. Phase-selective entrainment of nonlinear oscillator ensembles

    DOE PAGESBeta

    Zlotnik, Anatoly V.; Nagao, Raphael; Kiss, Istvan Z.; Li, Jr -Shin

    2016-03-18

    The ability to organize and finely manipulate the hierarchy and timing of dynamic processes is important for understanding and influencing brain functions, sleep and metabolic cycles, and many other natural phenomena. However, establishing spatiotemporal structures in biological oscillator ensembles is a challenging task that requires controlling large collections of complex nonlinear dynamical units. In this report, we present a method to design entrainment signals that create stable phase patterns in ensembles of heterogeneous nonlinear oscillators without using state feedback information. We demonstrate the approach using experiments with electrochemical reactions on multielectrode arrays, in which we selectively assign ensemble subgroups intomore » spatiotemporal patterns with multiple phase clusters. As a result, the experimentally confirmed mechanism elucidates the connection between the phases and natural frequencies of a collection of dynamical elements, the spatial and temporal information that is encoded within this ensemble, and how external signals can be used to retrieve this information.« less

  14. Study of a three-stage fluidized bed process treating acrylic synthetic-fiber manufacturing wastewater containing high-strength nitrogenous compounds.

    PubMed

    Cheng, S S; Chen, Y N; Wu, K L; Chuang, H P; Chen, S D

    2004-01-01

    Polyacrylonitrile (PAN) is one of the major synthetic fibers commonly used in the mass production of clothing. The chemical synthesis of PAN is carried out by polymerization of the acrylonitrile (AN) monomers with co-monomers such as vinyl acetate, methyl acrylate and cyclohexyl acrylate. Using water quality analysis of the PAN wastewater, high concentration of organic nitrogen was found and the TKN/COD ratios achieved were 0.15-0.26, indicating the complicated biodegradation characteristics for the PAN wastewater. In order to enhance biodegradation of nitrogenous compounds in PAN wastewater, a combined three-stage process of thermophilic anaerobic/anoxic denitrification/aerobic nitrification fluidized bed reactors was employed. The results indicated that the concentration of effluent in the three-stage process of OD and organic nitrogen was 175 mg/L and 13 mg/L, respectively. Furthermore, molecular biotechnology was applied to study the microbial population in the thermophilic anaerobic fluidized bed reactor. From the results of denaturing gradient gel electrophoresis, the diversity of PAN-degrading bacteria would change in different volumetric loading. Furthermore, the bacteria communities in the thermophilic anaerobic fluidized bed reactor were also studied by fluorescence in situ hybridization and confocal laser scanning microscopy. Alpha and delta-Proteobacteria were dominant in the bacteria population, and some high G+C content bacteria and Clostridium could be characterized in this system. PMID:15137414

  15. Adapting Data Processing To Compare Model and Experiment Accurately: A Discrete Element Model and Magnetic Resonance Measurements of a 3D Cylindrical Fluidized Bed.

    PubMed

    Boyce, Christopher M; Holland, Daniel J; Scott, Stuart A; Dennis, John S

    2013-12-18

    Discrete element modeling is being used increasingly to simulate flow in fluidized beds. These models require complex measurement techniques to provide validation for the approximations inherent in the model. This paper introduces the idea of modeling the experiment to ensure that the validation is accurate. Specifically, a 3D, cylindrical gas-fluidized bed was simulated using a discrete element model (DEM) for particle motion coupled with computational fluid dynamics (CFD) to describe the flow of gas. The results for time-averaged, axial velocity during bubbling fluidization were compared with those from magnetic resonance (MR) experiments made on the bed. The DEM-CFD data were postprocessed with various methods to produce time-averaged velocity maps for comparison with the MR results, including a method which closely matched the pulse sequence and data processing procedure used in the MR experiments. The DEM-CFD results processed with the MR-type time-averaging closely matched experimental MR results, validating the DEM-CFD model. Analysis of different averaging procedures confirmed that MR time-averages of dynamic systems correspond to particle-weighted averaging, rather than frame-weighted averaging, and also demonstrated that the use of Gaussian slices in MR imaging of dynamic systems is valid. PMID:24478537

  16. Adapting Data Processing To Compare Model and Experiment Accurately: A Discrete Element Model and Magnetic Resonance Measurements of a 3D Cylindrical Fluidized Bed

    PubMed Central

    2013-01-01

    Discrete element modeling is being used increasingly to simulate flow in fluidized beds. These models require complex measurement techniques to provide validation for the approximations inherent in the model. This paper introduces the idea of modeling the experiment to ensure that the validation is accurate. Specifically, a 3D, cylindrical gas-fluidized bed was simulated using a discrete element model (DEM) for particle motion coupled with computational fluid dynamics (CFD) to describe the flow of gas. The results for time-averaged, axial velocity during bubbling fluidization were compared with those from magnetic resonance (MR) experiments made on the bed. The DEM-CFD data were postprocessed with various methods to produce time-averaged velocity maps for comparison with the MR results, including a method which closely matched the pulse sequence and data processing procedure used in the MR experiments. The DEM-CFD results processed with the MR-type time-averaging closely matched experimental MR results, validating the DEM-CFD model. Analysis of different averaging procedures confirmed that MR time-averages of dynamic systems correspond to particle-weighted averaging, rather than frame-weighted averaging, and also demonstrated that the use of Gaussian slices in MR imaging of dynamic systems is valid. PMID:24478537

  17. Continuous processing of recombinant proteins: Integration of inclusion body solubilization and refolding using simulated moving bed size exclusion chromatography with buffer recycling.

    PubMed

    Wellhoefer, Martin; Sprinzl, Wolfgang; Hahn, Rainer; Jungbauer, Alois

    2013-12-01

    An integrated process which combines continuous inclusion body dissolution with NaOH and continuous matrix-assisted refolding based on closed-loop simulated moving bed size exclusion chromatography was designed and experimentally evaluated at laboratory scale. Inclusion bodies from N(pro) fusion pep6His and N(pro) fusion MCP1 from high cell density fermentation were continuously dissolved with NaOH, filtered and mixed with concentrated refolding buffer prior to refolding by size exclusion chromatography (SEC). This process enabled an isocratic operation of the simulated moving bed (SMB) system with a closed-loop set-up with refolding buffer as the desorbent buffer and buffer recycling by concentrating the raffinate using tangential flow filtration. With this continuous refolding process, we increased the refolding and cleavage yield of both model proteins by 10% compared to batch dilution refolding. Furthermore, more than 99% of the refolding buffer of the raffinate could be recycled which reduced the buffer consumption significantly. Based on the actual refolding data, we compared throughput, productivity, and buffer consumption between two batch dilution refolding processes - one using urea for IB dissolution, the other one using NaOH for IB dissolution - and our continuous refolding process. The higher complexity of the continuous refolding process was rewarded with higher throughput and productivity as well as significantly lower buffer consumption compared to the batch dilution refolding processes.

  18. Pressurized fluidized-bed hydroretorting of eastern oil shales. Volume 2, Task 3, Testing of process improvement concepts: Final report, September 1987--May 1991

    SciTech Connect

    Not Available

    1992-03-01

    This final report, Volume 2, on ``Process Improvement Concepts`` presents the results of work conducted by the Institute of Gas Technology (IGT), the Illinois Institute of Technology (IIT), and the Ohio State University (OSU) to develop three novel approaches for desulfurization that have shown good potential with coal and could be cost-effective for oil shales. These are (1) In-Bed Sulfur Capture using different sorbents (IGT), (2) Electrostatic Desulfurization (IIT), and (3) Microbial Desulfurization and Denitrification (OSU and IGT). Results of work on electroseparation of shale oil and fines conducted by IIT is included in this report, as well as work conducted by IGT to evaluate the restricted pipe discharge system. The work was conducted as part of the overall program on ``Pressurized Fluidized-Bed Hydroretorting of Eastern Oil Shales.``

  19. Out-of-synchrony speech entrainment in developmental dyslexia.

    PubMed

    Molinaro, Nicola; Lizarazu, Mikel; Lallier, Marie; Bourguignon, Mathieu; Carreiras, Manuel

    2016-08-01

    Developmental dyslexia is a reading disorder often characterized by reduced awareness of speech units. Whether the neural source of this phonological disorder in dyslexic readers results from the malfunctioning of the primary auditory system or damaged feedback communication between higher-order phonological regions (i.e., left inferior frontal regions) and the auditory cortex is still under dispute. Here we recorded magnetoencephalographic (MEG) signals from 20 dyslexic readers and 20 age-matched controls while they were listening to ∼10-s-long spoken sentences. Compared to controls, dyslexic readers had (1) an impaired neural entrainment to speech in the delta band (0.5-1 Hz); (2) a reduced delta synchronization in both the right auditory cortex and the left inferior frontal gyrus; and (3) an impaired feedforward functional coupling between neural oscillations in the right auditory cortex and the left inferior frontal regions. This shows that during speech listening, individuals with developmental dyslexia present reduced neural synchrony to low-frequency speech oscillations in primary auditory regions that hinders higher-order speech processing steps. The present findings, thus, strengthen proposals assuming that improper low-frequency acoustic entrainment affects speech sampling. This low speech-brain synchronization has the strong potential to cause severe consequences for both phonological and reading skills. Interestingly, the reduced speech-brain synchronization in dyslexic readers compared to normal readers (and its higher-order consequences across the speech processing network) appears preserved through the development from childhood to adulthood. Thus, the evaluation of speech-brain synchronization could possibly serve as a diagnostic tool for early detection of children at risk of dyslexia. Hum Brain Mapp 37:2767-2783, 2016. © 2016 Wiley Periodicals, Inc.

  20. Out-of-synchrony speech entrainment in developmental dyslexia.

    PubMed

    Molinaro, Nicola; Lizarazu, Mikel; Lallier, Marie; Bourguignon, Mathieu; Carreiras, Manuel

    2016-08-01

    Developmental dyslexia is a reading disorder often characterized by reduced awareness of speech units. Whether the neural source of this phonological disorder in dyslexic readers results from the malfunctioning of the primary auditory system or damaged feedback communication between higher-order phonological regions (i.e., left inferior frontal regions) and the auditory cortex is still under dispute. Here we recorded magnetoencephalographic (MEG) signals from 20 dyslexic readers and 20 age-matched controls while they were listening to ∼10-s-long spoken sentences. Compared to controls, dyslexic readers had (1) an impaired neural entrainment to speech in the delta band (0.5-1 Hz); (2) a reduced delta synchronization in both the right auditory cortex and the left inferior frontal gyrus; and (3) an impaired feedforward functional coupling between neural oscillations in the right auditory cortex and the left inferior frontal regions. This shows that during speech listening, individuals with developmental dyslexia present reduced neural synchrony to low-frequency speech oscillations in primary auditory regions that hinders higher-order speech processing steps. The present findings, thus, strengthen proposals assuming that improper low-frequency acoustic entrainment affects speech sampling. This low speech-brain synchronization has the strong potential to cause severe consequences for both phonological and reading skills. Interestingly, the reduced speech-brain synchronization in dyslexic readers compared to normal readers (and its higher-order consequences across the speech processing network) appears preserved through the development from childhood to adulthood. Thus, the evaluation of speech-brain synchronization could possibly serve as a diagnostic tool for early detection of children at risk of dyslexia. Hum Brain Mapp 37:2767-2783, 2016. © 2016 Wiley Periodicals, Inc. PMID:27061643

  1. Listening to debris flows: What can ground vibrations tell us about debris-flow entrainment and flow density?

    NASA Astrophysics Data System (ADS)

    Kean, J. W.; Coe, J. A.; Coviello, V.; Smith, J. B.; McCoy, S. W.; Arattano, M.

    2015-12-01

    Debris flows generate seismic waves as they travel downslope and can grow in size and destructive potential by entraining sediment along their paths. Recent observations from the Chalk Cliffs monitoring site in central Colorado show there is a systematic relation between the magnitude of seismic waves and both (1) the amount of erodible sediment beneath the flow, and (2) the density of the flow. Specifically, we observed that the spectral power of debris-flow induced ground motion increased by two orders of magnitude after a 34-cm layer of bed sediment was eroded from a bedrock channel. We also observed that high-density (sediment-rich) debris-flow surges generate about two orders of magnitude greater spectral power than low-density (water-rich) surges of similar thickness. These observations lead us to the hypothesis that the recorded ground motions are generated primarily by the impacts of grains on bedrock sections of the channel. This hypothesis is supported by ball drop tests which showed that impacts on deformable loose bed sediment in the channel (if present) generate negligibly small surface waves compared to impacts on bedrock. We thus expect debris-flow induced ground motion to increase as sediment entrainment exposes bedrock in channel, and as the flow density (and number of grains) increase. We explored the connection between ground motions and debris-flow entrainment/density by adapting a model from fluvial seismology [Tsai et al., GRL, 2012]. We used the adapted model to estimate rates of sediment entrainment and the density of flows over bare bedrock channels. Our estimates of sediment entrainment compared favorably with previous direct measurements of entrainment rates at the site. Estimates of flow density are sufficiently accurate to distinguish between three density levels: low (<1200 kg/m3), medium (1200-1600 kg/m3), and high (<1600 kg/m3). Although more testing is needed, these initial results suggest the approach may be a new indirect way to

  2. Anaerobic/aerobic treatment of a petrochemical wastewater from two aromatic transformation processes by fluidized bed reactors.

    PubMed

    Estrada-Arriaga, Edson B; Ramirez-Camperos, Esperanza; Moeller-Chavez, Gabriela E; García-Sanchez, Liliana

    2012-01-01

    An integrated fluidized bed reactor (FBR) has been employed as the treatment for petrochemical industry wastewaters with high organic matter and aromatic compounds, under anaerobic and aerobic conditions. The system was operated at hydraulic residence time (HRT) of 2.7 and 2.2 h in the anaerobic and aerobic reactor, respectively. The degree of fluidization in the beds was 30%. This system showed a high performance on the removal of organic matter and aromatic compounds. At different organic loading rates (OLR), the chemical oxygen demand (COD) removal in the anaerobic reactor was close to 85% and removals of the COD up to 94% were obtained in the aerobic reactor. High removals of benzene, toluene, ethylbenzene, xylenes, styrene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene and naphthalene were achieved in this study. PMID:23109595

  3. Theoretical solution for the cool-down or warm-up process of a pipeline or a packed bed

    NASA Astrophysics Data System (ADS)

    Hofmann, A.

    2000-01-01

    For planning the start-up procedure of a pipeline under realistic conditions the cool-down or warm-up behaviour should be known in advance. The relation between the cool-down or warm-up time and the mass-flow rate in the pipeline should be known in particular. Based on heat balances theoretical relations had been derived to enable appropriate estimations. These derived theoretical relations are also valid for the cool-down or warm-up of packed beds used as heat accumulators, e.g., in regenerators. A simple experimental method is suggested to determine the heat transfer coefficient in a packed bed using the theoretical relation for the gas temperature as a function of time and length. As all variables in the formulae are dimensionless, normalized diagrams have been developed, which are valid for all the cases discussed.

  4. Coal processing for fuel cell utilization. Task 11: Fluidized bed coal gasification model; data analysis and predictions

    NASA Astrophysics Data System (ADS)

    Finson, M. L.

    1980-01-01

    Development and application of a computational model for fluidized bed gasification of coal is described. A two phase bubbling bed reactor model accounts for the development of bubbles, clouds, and emulsion, with a new statistical treatment to predict bubble size. Coal char reactivity is described in detail, using models for carbon heterogeneous chemistry, pore structure, and mass transport previously developed. Volatile release is handled in a semiempirical manner, and potential gas phase reactions between fuel and oxygen in the bubbles are allowed. The data imply larger gas by passing and particle carry over than predicted, and the computed performance exceeds that observed. The computer program was exercised to map out gasifier performance over a range of conditions. It is shown that proper fluidization often requires more gas flow than can be accommodated chemically, due to limited kinetics and mass transport.

  5. Rhythm as a Coordinating Device: Entrainment with Disordered Speech

    ERIC Educational Resources Information Center

    Borrie, Stephanie A.; Liss, Julie M.

    2014-01-01

    Purpose: The rhythmic entrainment (coordination) of behavior during human interaction is a powerful phenomenon, considered essential for successful communication, supporting social and emotional connection, and facilitating sense-making and information exchange. Disruption in entrainment likely occurs in conversations involving those with speech…

  6. Defining the Entrainment Zone in Stratocumulus-topped Boundary Layers

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Zhou, M.; Kalogiros, J. A.; Lenschow, D. H.; Dai, C.; Wang, S.

    2010-12-01

    The presence of an entrainment zone near the top of the stratocumulus-topped boundary layers has been identified by many early studies. However, the definition of the entrainment zone was rather vague. We have examined the fine vertical variations of cloud liquid water content, wind, temperature and humidity near the stratocumulus top and developed a new method to identify the entrainment zone objectively. Aircraft measurements from various field projects in stratocumulus-topped boundary layers are used, taking advantage of the fast sampling capability of many of the aircraft sensors. Because of the inhomogeneous mixing of two air masses with distinctively different thermodynamic properties, the magnitude of temperature perturbations within the entrainment zone is significantly larger than those above or below. This characteristics is used to define the upper and lower boundaries of the entrainment zone using a wavelet spectra analyses. The definition of the entrainment zone is further evaluated by the presence of a linear mixing line through mixing line analyses. Various other interfaces at the cloud top are also examined, including the cloud interface, temperature interface (inversion), and moisture interface. The heights of these interfaces are examined relative to the height of the entrainment zone. This study also systematically revealed the presence of turbulence above the local cloud top and/or above the entrainment zone. Wind shear near the cloud top is one possible source that generated local turbulence. Other potential sources of turbulence will also be discussed.

  7. "Who's been feeding in my bed?" Benthivorous fish affect fluvial sediment transport - fact or fairy tale?

    NASA Astrophysics Data System (ADS)

    Rice, Stephen; Pledger, Andrew; Smith, James; Toone, Julia

    2016-04-01

    Many species of fish are benthivorous - they forage for food in the river bed - and their foraging disturbs, displaces and sorts bed materials with implications for fluvial sediment transport. Flume experiments have confirmed that benthic foraging by Barbel (Barbus barbus (L.)) and Chub (Squalius cephalus (L.)) modifies the structure and topography of water-worked gravels, thereby increasing particle entrainment probabilities and the quantity of sediment mobilised during experimental high flows. Field experiments and observations have demonstrated the impact of foraging on patch-scale bed disturbance, gravel structure, grain displacements and grain-size sorting. Initial ex-situ experiments support the suggestion that in low gradient rivers, shoals of fish like Bream (Abramis brama (L.)) entrain fine bed sediments, adding a biotic surcharge to the suspended sediment flux and modifying bed topography. These results underpin a novel proposal: that there is an aggregate, cumulative effect of benthic foraging on fluvial sediment transport at larger scales, including at scales where the contribution to sediment movement and river channel behaviour generates management concerns. Evaluating this proposal is a long-term goal, which is based on two intermediate objectives: to develop deeper mechanistic understanding of foraging impacts and to establish the spatial and temporal extent of geomorphologically significant feeding behaviours in river systems. The latter is crucial because field data are currently limited to a single reach on one UK river. It is reasonable to hypothesise that foraging impacts are spatially and temporally widespread because obligate and opportunistic benthic feeding is common and fish feed throughout their life. However, the effectiveness of foraging as a geomorphological process is likely to vary with factors including substrate size, fish community composition, food availability, water temperature, river flows and seasonal changes in fish

  8. High-Resolution Entrainment in Stratocumulus During the POST Campaign

    NASA Astrophysics Data System (ADS)

    Gerber, H. E.

    2012-12-01

    In July and August of 2008 an NSF-supported field campaign called POST (Physics of Stratocumulus Top) was conducted off the California coast using the fully-instrumented Twin Otter aircraft from the Naval Post Graduate School. POST provided the first opportunity to closely co-locate on an aircraft high-rate and time synchronized microphysics (PVM; LWC and effective radius) and thermodynamics (UFT; Ultra-Fast Temperature) probes and a gust probe to produce measurements of entrainment fluxes and features over entrainment scales thought to be important in warm stratocumulus (Sc). This combination of probes permitted investigating the properties of individual entrained parcels Seventeen flights were conducted during POST in a quasi-Lagrangian fashion in largely unbroken stratocumulus. The horizontal fight path was adjusted to follow the mean air velocity in the Sc. The vertical flight path concentrated on flying between 100-m above and below the cloud-top interface; and some additional profiles were flown to various higher and lower levels where flux runs were made. This presentation describes the analysis of this unique and excellent data set including the following: The data permitted testing Lilly's classical theory for the entrainment velocity where its application requires strong jumps of temperature and moisture across the inversion located above cloud top, a linear flux of the entrained scalar below cloud top, and entrained parcels that descend. All flights showed Sc with wind shear and mixing at cloud top with some strong enough to dissipate the Sc. The relationship between shear and entrainment velocity is described. The pdf of the horizontal size of entrainment parcels vs entrainment flux is established for all flights to help in choosing grid-sizes for modeling. High -resolution in-cloud temperature and LWC measurements in entrained parcels reveal the relative importance of radiative cooling vs cooling by liquid water evaporation in causing buoyancy reversal

  9. Ground-Based Remote Retrievals of Cumulus Entrainment Rates

    SciTech Connect

    Wagner, Timothy J.; Turner, David D.; Berg, Larry K.; Krueger, Steven K.

    2013-07-26

    While fractional entrainment rates for cumulus clouds have typically been derived from airborne observations, this limits the size and scope of available data sets. To increase the number of continental cumulus entrainment rate observations available for study, an algorithm for retrieving them from ground-based remote sensing observations has been developed. This algorithm, called the Entrainment Rate In Cumulus Algorithm (ERICA), uses the suite of instruments at the Southern Great Plains (SGP) site of the United States Department of Energy's Atmospheric Radiation Measurement (ARM) Climate Research Facility as inputs into a Gauss-Newton optimal estimation scheme, in which an assumed guess of the entrainment rate is iteratively adjusted through intercomparison of modeled liquid water path and cloud droplet effective radius to their observed counterparts. The forward model in this algorithm is the Explicit Mixing Parcel Model (EMPM), a cloud parcel model that treats entrainment as a series of discrete entrainment events. A quantified value for measurement uncertainty is also returned as part of the retrieval. Sensitivity testing and information content analysis demonstrate the robust nature of this method for retrieving accurate observations of the entrainment rate without the drawbacks of airborne sampling. Results from a test of ERICA on three months of shallow cumulus cloud events show significant variability of the entrainment rate of clouds in a single day and from one day to the next. The mean value of 1.06 km-¹ for the entrainment rate in this dataset corresponds well with prior observations and simulations of the entrainment rate in cumulus clouds.

  10. Fluidized bed deposition of diamond

    DOEpatents

    Laia, Jr., Joseph R.; Carroll, David W.; Trkula, Mitchell; Anderson, Wallace E.; Valone, Steven M.

    1998-01-01

    A process for coating a substrate with diamond or diamond-like material including maintaining a substrate within a bed of particles capable of being fluidized, the particles having substantially uniform dimensions and the substrate characterized as having different dimensions than the bed particles, fluidizing the bed of particles, and depositing a coating of diamond or diamond-like material upon the substrate by chemical vapor deposition of a carbon-containing precursor gas mixture, the precursor gas mixture introduced into the fluidized bed under conditions resulting in excitation mechanisms sufficient to form the diamond coating.

  11. The relative importance of sunrise and sunset for entrainment of oviposition in the fowl.

    PubMed

    Bhatti, B M; Morris, T R

    1978-05-01

    1. A series of four "sunset" signals, without associated sunrises, was given to laying hens by reducing light intensity in steps from 190 lx to 63, 21, 7 and 2 lx at 24-h intervals. Four "sunrises" were given by reversing the process. Treatments involving single "sunrises", single "sunsets" and combinations of sunrises and sunsets at 12-h intervals were also tested. 2. Only treatments which included one or more sunset signals were found to give full entrainment of oviposition, as judged by the proportion of eggs laid in a modal 8-h segment of each 24-h cycle. Full entrainment was achieved if the sunset occurred between 16.00 h and midnight, but not if the sunset occurred in the morning hours. Treatments involving only sunrise signals did not fully entrain oviposition but did have effect on the timing and distribution of ovipositions. Sunrises given in association with sunsets increased the degree of entrainment achieved, as compared with the sunset signal alone. 3. This study indicates that sunset is a potent synchronising agent for phase setting oviposition and, presumably, for phase setting the endogenous circadian rhythm of the fowl. Sunrise can also exert a modifying influence.

  12. Exploring how musical rhythm entrains brain activity with electroencephalogram frequency-tagging.

    PubMed

    Nozaradan, Sylvie

    2014-12-19

    The ability to perceive a regular beat in music and synchronize to this beat is a widespread human skill. Fundamental to musical behaviour, beat and meter refer to the perception of periodicities while listening to musical rhythms and often involve spontaneous entrainment to move on these periodicities. Here, we present a novel experimental approach inspired by the frequency-tagging approach to understand the perception and production of rhythmic inputs. This approach is illustrated here by recording the human electroencephalogram responses at beat and meter frequencies elicited in various contexts: mental imagery of meter, spontaneous induction of a beat from rhythmic patterns, multisensory integration and sensorimotor synchronization. Collectively, our observations support the view that entrainment and resonance phenomena subtend the processing of musical rhythms in the human brain. More generally, they highlight the potential of this approach to help us understand the link between the phenomenology of musical beat and meter and the bias towards periodicities arising under certain circumstances in the nervous system. Entrainment to music provides a highly valuable framework to explore general entrainment mechanisms as embodied in the human brain. PMID:25385771

  13. A Simple State-Determined Model Reproduces Entrainment and Phase-Locking of Human Walking

    PubMed Central

    Ahn, Jooeun; Hogan, Neville

    2012-01-01

    Theoretical studies and robotic experiments have shown that asymptotically stable periodic walking may emerge from nonlinear limit-cycle oscillators in the neuro-mechanical periphery. We recently reported entrainment of human gait to periodic mechanical perturbations with two essential features: 1) entrainment occurred only when the perturbation period was close to the original (preferred) walking period, and 2) entrainment was always accompanied by phase locking so that the perturbation occurred at the end of the double-stance phase. In this study, we show that a highly-simplified state-determined walking model can reproduce several salient nonlinear limit-cycle behaviors of human walking: 1) periodic gait that is 2) asymptotically stable; 3) entrainment to periodic mechanical perturbations only when the perturbation period is close to the model's unperturbed period; and 4) phase-locking to locate the perturbation at the end of double stance. Importantly, this model requires neither supra-spinal control nor an intrinsic self-sustaining neural oscillator such as a rhythmic central pattern generator. Our results suggest that several prominent limit-cycle features of human walking may stem from simple afferent feedback processes without significant involvement of supra-spinal control or a self-sustaining oscillatory neural network. PMID:23152761

  14. Comparison of Machine Learning methods for incipient motion in gravel bed rivers

    NASA Astrophysics Data System (ADS)

    Valyrakis, Manousos

    2013-04-01

    Soil erosion and sediment transport of natural gravel bed streams are important processes which affect both the morphology as well as the ecology of earth's surface. For gravel bed rivers at near incipient flow conditions, particle entrainment dynamics are highly intermittent. This contribution reviews the use of modern Machine Learning (ML) methods implemented for short term prediction of entrainment instances of individual grains exposed in fully developed near boundary turbulent flows. Results obtained by network architectures of variable complexity based on two different ML methods namely the Artificial Neural Network (ANN) and the Adaptive Neuro-Fuzzy Inference System (ANFIS) are compared in terms of different error and performance indices, computational efficiency and complexity as well as predictive accuracy and forecast ability. Different model architectures are trained and tested with experimental time series obtained from mobile particle flume experiments. The experimental setup consists of a Laser Doppler Velocimeter (LDV) and a laser optics system, which acquire data for the instantaneous flow and particle response respectively, synchronously. The first is used to record the flow velocity components directly upstream of the test particle, while the later tracks the particle's displacements. The lengthy experimental data sets (millions of data points) are split into the training and validation subsets used to perform the corresponding learning and testing of the models. It is demonstrated that the ANFIS hybrid model, which is based on neural learning and fuzzy inference principles, better predicts the critical flow conditions above which sediment transport is initiated. In addition, it is illustrated that empirical knowledge can be extracted, validating the theoretical assumption that particle ejections occur due to energetic turbulent flow events. Such a tool may find application in management and regulation of stream flows downstream of dams for stream

  15. Staged fluidized bed

    DOEpatents

    Mallon, R.G.

    1983-05-13

    The invention relates to oil shale retorting and more particularly to staged fluidized bed oil shale retorting. Method and apparatus are disclosed for narrowing the distribution of residence times of any size particle and equalizing the residence times of large and small particles in fluidized beds. Particles are moved up one fluidized column and down a second fluidized column with the relative heights selected to equalize residence times of large and small particles. Additional pairs of columns are staged to narrow the distribution of residence times and provide complete processing of the material.

  16. Bed Bugs FAQs

    MedlinePlus

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

  17. Granular filtration in a fluidized bed

    SciTech Connect

    Mei, J.S.; Yue, P.C.; Halow, J.S.

    1995-12-01

    Successful development of advanced coal-fired power conversion systems often require reliable and efficient cleanup devices which can remove particulate and gaseous pollutants from high-temperature high-pressure gas streams. A novel filtration concept for particulate cleanup has been developed at the Morgantown Energy Technology Center (METC) of the U.S. Department of Energy. The filtration system consists of a fine metal screen filter immersed in a fluidized bed of granular material. As the gas stream passes through the fluidized bed, a layer of the bed granular material is entrained and deposited at the screen surface. This material provides a natural granular filter to separate fine particles from the gas stream passing through the bed. Since the filtering media is the granular material supplied by the fluidized bed, the filter is not subjected to blinding like candle filters. Because only the inflowing gas, not fine particle cohesive forces, maintains the granular layer at the screen surface, once the thickness and permeability of the granular layer is stabilized, it remains unchanged as long as the in-flowing gas flow rate remains constant. The weight of the particles and the turbulent nature of the fluidized bed limits the thickness of the granular layer on the filter leading to a self-cleaning attribute of the filter. This paper presents work since then on a continuous filtration system. The continuous filtration testing system consisted of a filter, a two-dimensional fluidized-bed, a continuous powder feeder, a laser-based in-line particle counting, sizing, and velocimeter (PCSV), and a continuous solids feeding/bed material withdrawal system. The two-dimensional, transparent fluidized-bed allowed clear observation of the general fluidized state of the granular material and the conditions under which fines are captured by the granular layer.

  18. Dry Air Entrainment into Hurricane Earl

    NASA Technical Reports Server (NTRS)

    Guillory, Anthony R.; Jedlovec, Gary J.; Atkinson, Robert J.; Hood, Robbie E.; LaFontaine, Frank J.

    2000-01-01

    Hurricane Earl formed in the Gulf of Mexico in September 1998. It quickly was upgraded from a tropical disturbance to tropical storm status and then to a hurricane. Earl possessed hybrid (tropical and extratropical) characteristics throughout its lifetime. The system maintained and erratic track, which led to wide variability in the operational track forecasts. It eventually made landfall on the Florida panhandle on 2 September and raced northeastward. During August and September 1998, NASA conducted the third Convection and Moisture Experiment (CAMEX-3). The experiment was focused on studying hurricanes with an emphasis toward developing a better understanding of their intensification and motion. Earl provides a unique opportunity to utilize high spatial and temporal resolution data collected from the DC-8 and high altitude ER-2 NASA platforms, which flew over Earl as it made landfall. These data can also be put into broader view provided by other instruments from the Geosychronous Operational Environmental Satellites (GOES) and the Tropical Rainfall Measuring Mission (TRMM) satellites. Hurricane Earl was affected by entrainment of dry air from the northwest. Hurricane Isis was intensifying and approaching the Mexican Pacific coast with its associated outflow potentially affecting the inflow into Earl as the storm neared Florida. In addition, a longwave synoptic trough circulation was present over the eastern U.S. Either or both of these could be responsible for the dry air into the system. This paper will focus on identifying the source of the dry by using upper-level wind and moisture fields derived from the GOES 6.7 um water vapor imagery. We will attempt to relate the large-scale observations to those from the NASA aircraft. An infrared instrument onboard the ER-2 also has a similar wavelength and may be able to confirm some of the GOES findings. In addition, a microwave radiometer with 4 channels focused on measuring precipitation and its associated ice

  19. Mutual regulation causes co-entrainment between a synthetic oscillator and the bacterial cell cycle.

    PubMed

    Dies, Marta; Galera-Laporta, Leticia; Garcia-Ojalvo, Jordi

    2016-04-18

    The correct functioning of cells requires the orchestration of multiple cellular processes, many of which are inherently dynamical. The conditions under which these dynamical processes entrain each other remain unclear. Here we use synthetic biology to address this question in the case of concurrent cellular oscillations. Specifically, we study at the single-cell level the interaction between the cell division cycle and a robust synthetic gene oscillator in Escherichia coli. Our results suggest that cell division is able to partially entrain the synthetic oscillations under normal growth conditions, by driving the periodic replication of the genes involved in the oscillator. Coupling the synthetic oscillations back into the cell cycle via the expression of a key regulator of chromosome replication increases the synchronization between the two periodic processes. A simple computational model allows us to confirm this effect.

  20. Method and apparatus for a combination moving bed thermal treatment reactor and moving bed filter

    DOEpatents

    Badger, Phillip C.; Dunn, Jr., Kenneth J.

    2015-09-01

    A moving bed gasification/thermal treatment reactor includes a geometry in which moving bed reactor particles serve as both a moving bed filter and a heat carrier to provide thermal energy for thermal treatment reactions, such that the moving bed filter and the heat carrier are one and the same to remove solid particulates or droplets generated by thermal treatment processes or injected into the moving bed filter from other sources.

  1. On the maximum grain size entrained by photoevaporative winds

    NASA Astrophysics Data System (ADS)

    Hutchison, Mark A.; Laibe, Guillaume; Maddison, Sarah T.

    2016-09-01

    We model the behaviour of dust grains entrained by photoevaporation-driven winds from protoplanetary discs assuming a non-rotating, plane-parallel disc. We obtain an analytic expression for the maximum entrainable grain size in extreme-UV radiation-driven winds, which we demonstrate to be proportional to the mass loss rate of the disc. When compared with our hydrodynamic simulations, the model reproduces almost all of the wind properties for the gas and dust. In typical turbulent discs, the entrained grain sizes in the wind are smaller than the theoretical maximum everywhere but the inner disc due to dust settling.

  2. The role of entrainment by falling raindrops in microbursts

    NASA Technical Reports Server (NTRS)

    Krueger, Steven K.

    1988-01-01

    The numerical model of Krueger et al. (1986) for dry microburst simulations is used to study the role of entrainment by falling raindrops. Two series of numerical simulations were conducted: a control series, and a series with the raindrop fall speed set to zero so that the rain moved with the air instead of falling through it. The results show that entrainment due to falling raindrops helps microbursts with large raindrop mixing ratios to form in stable stratifications. It is found that entrainment appears to contribute to the small spatial and temporal scales that characterize microburst outflows.

  3. 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.

  4. Microstructure measurements and estimates of entrainment in the Denmark Strait overflow plume

    NASA Astrophysics Data System (ADS)

    Paka, V.; Zhurbas, V.; Rudels, B.; Quadfasel, D.; Korzh, A.; Delisi, D.

    2013-07-01

    To examine processes controlling the entrainment of ambient water into the Denmark Strait overflow (DSO) plume/gravity current, measurements of turbulent dissipation rate were carried out by a quasi-free-falling (tethered) microstructure profiler (MSP). The MSP was specifically designed to collect data on dissipation-scale turbulence and fine thermohaline stratification in an ocean layer to depths of 3500 m. The task was to perform microstructure measurements in the DSO plume in the lower 300 m depth interval including the bottom mixed layer and the interfacial layer below the non-turbulent ambient water. The MSP was attached to a Rosette water sampler rack equipped with a SeaBird CTDO and an RD Instruments Lowered Acoustic Doppler Current Profiler (LADCP). At a chosen depth, the MSP was remotely released from the rack to perform measurements in a quasi-free-falling mode. Using the measured vertical profiles of dissipation, the entrainment rate as well as the bottom and interfacial stresses were estimated in the DSO plume at a location 200 km downstream of the sill at depths up to 1771 m. Dissipation-derived estimates of entrainment were found to be much smaller than bulk estimates of entrainment calculated from the downstream change of the mean properties in the plume, suggesting the lateral stirring due to meso-scale eddies rather than diapycnal mixing as the main contributor to entrainment. Dissipation-derived bottom stress estimates are argued to be roughly one-third the magnitude of those from log velocity profiles. In the interfacial layer, the Ozmidov scale calculated from turbulence dissipation rate and buoyancy frequency was found to be linearly proportional to the overturning scale extracted from conventional CTD data (the Thorpe scale), with a proportionality constant of 0.76, and a correlation coefficient of 0.77.

  5. Microstructure measurements and estimates of entrainment in the Denmark Strait overflow plume

    NASA Astrophysics Data System (ADS)

    Paka, V.; Zhurbas, V.; Rudels, B.; Quadfasel, D.; Korzh, A.; Delisi, D.

    2013-11-01

    To examine processes controlling the entrainment of ambient water into the Denmark Strait overflow (DSO) plume/gravity current, measurements of turbulent dissipation rate were carried out by a quasi-free-falling (tethered) microstructure profiler (MSP). The MSP was specifically designed to collect data on dissipation-scale turbulence and fine thermohaline stratification in an ocean layer located as deep as 3500 m. The task was to perform microstructure measurements in the DSO plume in the lower 300 m depth interval including the bottom mixed layer and the interfacial layer below the non-turbulent ambient water. The MSP was attached to a Rosette water sampler rack equipped with a SeaBird CTDO and an RD Instruments lowered acoustic Doppler current profiler (LADCP). At a chosen depth, the MSP was remotely released from the rack to perform measurements in a quasi-free-falling mode. Using the measured vertical profiles of dissipation, the entrainment rate as well as the bottom and interfacial stresses in the DSO plume were estimated at a location 200 km downstream of the sill at depths up to 1771 m. Dissipation-derived estimates of entrainment were found to be much smaller than bulk estimates of entrainment calculated from the downstream change of the mean properties in the plume, suggesting the lateral stirring due to mesoscale eddies rather than diapycnal mixing as the main contributor to entrainment. Dissipation-derived bottom stress estimates are argued to be roughly one third the magnitude of those derived from log velocity profiles. In the interfacial layer, the Ozmidov scale calculated from turbulence dissipation rate and buoyancy frequency was found to be linearly proportional to the overturning scale extracted from conventional CTD data (the Thorpe scale), with a proportionality constant of 0.76, and a correlation coefficient of 0.77.

  6. Organic Entrainment and Preservation in Volcanic Glasses

    NASA Technical Reports Server (NTRS)

    Wilhelm, Mary Beth; Ojha, Lujendra; Brunner, Anna E.; Dufek, Josef D.; Wray, James Joseph

    2014-01-01

    Unaltered pyroclastic deposits have previously been deemed to have "low" potential for the formation, concentration and preservation of organic material on the Martian surface. Yet volcanic glasses that have solidified very quickly after an eruption may be good candidates for containment and preservation of refractory organic material that existed in a biologic system pre-eruption due to their impermeability and ability to attenuate UV radiation. Analysis using NanoSIMS of volcanic glass could then be performed to both deduce carbon isotope ratios that indicate biologic origin and confirm entrainment during eruption. Terrestrial contamination is one of the biggest barriers to definitive Martian organic identification in soil and rock samples. While there is a greater potential to concentrate organics in sedimentary strata, volcanic glasses may better encapsulate and preserve organics over long time scales, and are widespread on Mars. If volcanic glass from many sites on Earth could be shown to contain biologically derived organics from the original environment, there could be significant implications for the search for biomarkers in ancient Martian environments.

  7. The role of attached kelp (seaweed) fronds in lowering threshold of coarse gravel entrainment in tidal flows.

    NASA Astrophysics Data System (ADS)

    Carling, Paul

    2014-05-01

    There is a long history of reports of attached kelp (seaweed) fronds aiding entrainment of coarse sediment by flotation. In the intertidal zone of the Severn Estuary (UK) cobbles were observed to overpass fine gravel plane-beds and pebble-gravel dunes in those instances where seaweed fronds were attached. However, overpassing clasts without attached fronds were rare. Flume experiments were conducted to measure the reduction in velocity and shear stresses required for initial motion when fronds were attached. A range of factors influence entrainment including the ratio of seaweed weight:clast weight and length:width ratio of the seaweed frond. Reynolds stresses for entrainment, and the critical velocity for entrainment were reduced by around a factor of two for attached fronds in contrast to stones without fronds. Reductions in the critical velocity were associated with an increase in the values of drag coefficients for clasts with attached fronds; the majority of the drag being associated with the frond widths rather than the frond lengths. The significance of this study is manifold with respect to deposition of outsized clasts in the modern marine environment and in the geological record. The reduced entrainment values explain the presence of large clasts in near-shore and off-shore environments where measured velocities otherwise are not competent. In addition, when clasts are deposited and buried by sediment the seaweed fronds decay and so the role of kelp is not immediately evident. Thus in the geological marine sedimentary record buried outsized clasts may be related to kelp transport in some instances.

  8. Formation and transport of PCDD/Fs in the packed bed of soil containing organic chloride during a thermal remediation process.

    PubMed

    Harjanto, Sri; Kasai, Eiki; Terui, Toshikatsu; Nakamura, Takashi

    2002-10-01

    The authors previously proposed the concept of a new thermal remediation process for particulate/powder materials contaminated by polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and experimentally verified its validity on the basis of process efficiency. However, contaminees such as soils and fly ashes from waste incinerators often contain a considerable amount of other chlorides, which may act as a main source of chlorine in the formation of PCDD/Fs via thermal processes. The present study aims to examine the formation and transport of PCDD/Fs in the packed bed of soil containing a chloride during the process. Polyvinyl chloride (PVC) polymer was mixed with soil sample as an organic chloride model. A laboratory-scale apparatus was employed as a process simulator. Further, a technique to quench the process was applied to observe the concentration distribution of PCDD/Fs in the solid bed in the vertical direction. The result shows that the PCDFs tend to form dominantly in the high temperature (calcination and/or combustion) zone and are successively trapped in the low temperature (wet) zone. Especially, TeCDF is the most dominant homologue contained in the wet zone and outlet gas. Although PCDD/Fs are once trapped at the wet zone, the concentration of the remediated materials gives fairly low value (1.9 pg/g-dry, 0.04 pg-TEQ/g-dry). It signifies that organic chlorides mingled in the solid contaminee not affect the removal efficiency of PCDD/Fs in the process. Nevertheless, attention should be paid to the potential emission of PCDD/Fs in the outlet gas due to the presence of organic chloride in the soil.

  9. A comparative efficacy study of photic driving brainwave entrainment technology with a novel form of more direct entrainment

    NASA Astrophysics Data System (ADS)

    Knowles, Richard Thomas

    This exploratory study compared the efficacy of a novel brainwave electromagnetic (EM) entrainment technology against a more conventional technology utilizing the photic-driving technique. Both experimental conditions were also compared with a 7-minute control session that took place immediately before each stimulation session. The Schumann Resonance (SR) frequency was selected as the delivery signal and was chosen because of previous findings suggesting that entrainment to this frequency can often produce transpersonal if not paranormal, experiences in the entrainee, which sometimes resemble remote viewing or out-of-body experiences. A pilot study determined which of two novel entrainment modalities (a copper coil or a 16-solenoid headset) worked most effectively for use with the rest of the study. In the main study, an artificial SR signal at 7.8Hz was delivered during the photic-driving sessions, but a recording of the real-time SR was used to deliver the entrainment signal during sessions devoted to the electromagnetic entrainment modality. Sixteen participants were recruited from the local area, and EEG recordings were acquired via a 32-channel Deymed electroencephalography system. Comparative analyses were performed between the control and experimental portions of each session to assess for efficacy of the novel entrainment modality used, and, in the main study, between the electromagnetic and photic-driving sessions, to assess for differential entrainment efficacy between these groups. A follow-up study was additionally performed primarily to determine whether responders could replicate their entrainment effect from the main study. Results showed that EM entrainment appeared to be possible but is not nearly as robust or reliable as photic driving. Additionally, no profound transpersonal or paranormal experiences were elicited during the course of the study, and, when asked, participants were not able to determine with any degree of success, when the

  10. Identification of data gaps found during the development of a zero-order model for a fluidized-bed retort/combustion process

    SciTech Connect

    Ammer, J.R.

    1986-01-01

    This technical note (TN) reports on the development of a zero-order ASPEN (Advanced System for Process Engineering) model for the fluidized-bed retort/combustion of an eastern oil shale. The objective of the work described was to identify data needs and to create a structure for future, more definitive models. New Albany shale was the initial reference eastern shale at the Department of Energy (DOE)/Morgantown Energy Technology Center (METC). A literature search on this shale was conducted to find the physical property data required for the ASPEN model. This TN discusses the types of missing or incomplete data, the process being modeled, and how process variables are affected by varying input parameters. The TN also presents recommendations for increasing the reliability of the simulation. 12 refs., 3 figs., 5 tabs.

  11. How coupling determines the entrainment of circadian clocks

    NASA Astrophysics Data System (ADS)

    Bordyugov, G.; Granada, A. E.; Herzel, H.

    2011-08-01

    Autonomous circadian clocks drive daily rhythms in physiology and behaviour. A network of coupled neurons, the suprachiasmatic nucleus (SCN), serves as a robust self-sustained circadian pacemaker. Synchronization of this timer to the environmental light-dark cycle is crucial for an organism's fitness. In a recent theoretical and experimental study it was shown that coupling governs the entrainment range of circadian clocks. We apply the theory of coupled oscillators to analyse how diffusive and mean-field coupling affects the entrainment range of interacting cells. Mean-field coupling leads to amplitude expansion of weak oscillators and, as a result, reduces the entrainment range. We also show that coupling determines the rigidity of the synchronized SCN network, i.e. the relaxation rates upon perturbation. Our simulations and analytical calculations using generic oscillator models help to elucidate how coupling determines the entrainment of the SCN. Our theoretical framework helps to interpret experimental data.

  12. The effects of antecedent flows on sediment entrainment in a mountain stream

    NASA Astrophysics Data System (ADS)

    Mao, L.; Comiti, F.; Dell'Agnese, A.; Engel, M.; Lucía, A.

    2014-12-01

    Bedload transport in mountain streams is notoriously difficult to measure, and substantial efforts are currently devoted to develop and test reliable surrogate techniques for quantifying bedload transport rates and size. Tracers, and in particular Passive Integrated Transponders (PITs), represent a powerful method to assess particle dynamics. PITs are usually searched after floods using a portable antenna, and grain size of tracers are typically related to the peak of the events. However, antennas fixed on the channel bed have the potential to identify the actual discharge at the time of transport. This work focuses on incipient motion of tracers measured with a stationary antenna in the upper part of a mountain basin (Saldur River, drainage area 18.6 km2, Italian Alps), where a glacier (2.3 km2) determines significant daily discharge fluctuations in summer. During the study period (2011 to 2013) flow discharge ranged from 1 to 10 m3s-1. Almost 600 clasts - ranging in diameter from 40 mm to about 0.5 m - were equipped with PITs and laid in a confined reach (6% slope) of the main channel featuring a bed morphology transitional from plane-bed to step-pool. PITs-clasts were gently placed on the bed surface few meters upstream of an antenna fixed on the channel bed, where flow stage is recorded every 10 min. Preliminary results indicate that discharge at the time of passage above the antenna is only slightly related to the size of transported tracers, providing little evidence of size-selectivity conditions in this stream. The influence of antecedent flows on incipient motion was then investigated dividing the maximum discharge recorded between each PIT placement and its subsequent entrainment by the actual critical discharge at the time of movement (ratio Qmax/Qc). It results that only 45% of tracers moved at Qmax/Qc ~ 1, and 70% of tracers moved at Qmax/Qc < 1.5. Therefore, about 30% of tracers had to previously experience a discharge substantially higher than the

  13. Lip movements entrain the observers' low-frequency brain oscillations to facilitate speech intelligibility.

    PubMed

    Park, Hyojin; Kayser, Christoph; Thut, Gregor; Gross, Joachim

    2016-01-01

    During continuous speech, lip movements provide visual temporal signals that facilitate speech processing. Here, using MEG we directly investigated how these visual signals interact with rhythmic brain activity in participants listening to and seeing the speaker. First, we investigated coherence between oscillatory brain activity and speaker's lip movements and demonstrated significant entrainment in visual cortex. We then used partial coherence to remove contributions of the coherent auditory speech signal from the lip-brain coherence. Comparing this synchronization between different attention conditions revealed that attending visual speech enhances the coherence between activity in visual cortex and the speaker's lips. Further, we identified a significant partial coherence between left motor cortex and lip movements and this partial coherence directly predicted comprehension accuracy. Our results emphasize the importance of visually entrained and attention-modulated rhythmic brain activity for the enhancement of audiovisual speech processing. PMID:27146891

  14. Fluidization quality analyzer for fluidized beds

    DOEpatents

    Daw, C.S.; Hawk, J.A.

    1995-07-25

    A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence. 9 figs.

  15. Fluidization quality analyzer for fluidized beds

    DOEpatents

    Daw, C. Stuart; Hawk, James A.

    1995-01-01

    A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence.

  16. Use of the Entrainment Form of the Exner Equation to Describe Effects of Patchy, Intermittent, Rarefied, Long-Distance Sediment Motions on Steepland Hillslopes

    NASA Astrophysics Data System (ADS)

    Furbish, D. J.

    2014-12-01

    Sediment particle motions on steepland hillslopes often are patchy, intermittent and rarefied. Such motions include particle skittering from rockfall, particle ravel, downslope dispersal of soil material due to tree throw and the activity of fossorial animals, soil slips, and transport by surface flows, particularly following fire. We may envision these as motions that start from the soil surface and then return to it after some finite time. Travel distances can be much larger than the soil thickness. Unless explicitly treated at the transport 'event' scale, the discontinuous qualities of these sediment motions in steeplands are at odds with continuum formulations of the sediment flux and the Exner equation of conservation as normally envisioned. The necessary averaging volumes and timescales are too large. Alternatively, the entrainment form of the Exner equation, when cast in probabilistic terms, provides a framework for describing the averaged effects of patchy, intermittent motions on the land surface. The formulation is mass conserving, "nonlocal" and scale independent, and it therefore does not require an averaging volume. However, there is a tradeoff. One must specify, based on theory or measurements, an ensemble distribution of particle travel distances that is to be considered a signature of the operative transport processes and extant hillslope conditions. Transport events (specifically, sediment travel distances) occurring over a specified interval of time represent "samples" drawn from this ensemble distribution. Predictions of changes in land-surface elevation are then statistically expected values, with associated uncertainty that depends on the frequency of transport. A growing set of field-based and high-resolution DEM measurements suggests that the nonlocal formulation is consistent with observed (one-dimensional) hillslope profiles in steeplands. We are extending the formulation to two-dimensional topography; initial results suggest a rich

  17. A parameterization of the depth of the entrainment zone

    NASA Technical Reports Server (NTRS)

    Boers, Reinout

    1989-01-01

    A theory of the parameterization of the entrainment zone depth has been developed based on conservation of energy. This theory suggests that the normalized entrainment zone depth is proportional to the inverse square root of the Richardson number. A comparison of this theory with atmospheric observations indicates excellent agreement. It does not adequately predict the laboratory data, although it improves on parcel theory, which is based on a momentum balance.

  18. How Entrainers Enhance Solubility in Supercritical Carbon Dioxide.

    PubMed

    Shimizu, Seishi; Abbott, Steven

    2016-04-21

    Supercritical carbon dioxide (scCO2) on its own can be a relatively poor solvent. However, the addition at relatively modest concentration of "entrainers", simple solvent molecules such as ethanol or acetone, can provide a significant boost in solubility, thereby enabling its industrial use. However, how entrainers work is still under debate; without an unambiguous explanation, it is hard to optimize entrainers for any specific solute. This paper demonstrates that a fundamental, assumption-free statistical thermodynamic theory, the Kirkwood-Buff (KB) theory, can provide an unambiguous explanation of the entrainer effect through an analysis of published experimental data. The KB theory shows that a strong solute-entrainer interaction accounts for the solubility enhancement, while CO2 density increase and/or CO2-entrainer interactions, which have been assumed widely in the literature, do not account for solubilization. This conclusion, despite the limited completeness of available data, is demonstrably robust; this can be shown by an order-of-magnitude analysis based upon the theory, and can be demonstrated directly through a public-domain "app", which has been developed to implement the theory.

  19. Entraining in trout: a behavioural and hydrodynamic analysis.

    PubMed

    Przybilla, Anja; Kunze, Sebastian; Rudert, Alexander; Bleckmann, Horst; Brücker, Christoph

    2010-09-01

    Rheophilic fish commonly experience unsteady flows and hydrodynamic perturbations. Instead of avoiding turbulent zones though, rheophilic fish often seek out these zones for station holding. A behaviour associated with station holding in running water is called entraining. We investigated the entraining behaviour of rainbow trout swimming in the wake of a D-shaped cylinder or sideways of a semi-infinite flat plate displaying a rounded leading edge. Entraining trout moved into specific positions close to and sideways of the submerged objects, where they often maintained their position without corrective body and/or fin motions. To identify the hydrodynamic mechanism of entraining, the flow characteristics around an artificial trout placed at the position preferred by entraining trout were analysed. Numerical simulations of the 3-D unsteady flow field were performed to obtain the unsteady pressure forces. Our results suggest that entraining trout minimise their energy expenditure during station holding by tilting their body into the mean flow direction at an angle, where the resulting lift force and wake suction force cancel out the drag. Small motions of the caudal and/or pectoral fins provide an efficient way to correct the angle, such that an equilibrium is even reached in case of unsteadiness imposed by the wake of an object. PMID:20709926

  20. Investigating the Sensitivity of Model Intraseasonal Variability to Minimum Entrainment

    NASA Astrophysics Data System (ADS)

    Hannah, W. M.; Maloney, E. D.

    2008-12-01

    Previous studies have shown that using a Relaxed Arakawa-Schubert (RAS) convective parameterization with appropriate convective triggers and assumptions about rain re-evaporation produces realistic intraseasonal variability. RAS represents convection with an ensemble of clouds detraining at different heights, each with different entrainment rate, the highest clouds having the lowest entrainment rates. If tropospheric temperature gradients are weak and boundary layer moist static energy is relatively constant, then by limiting the minimum entrainment rate deep convection is suppressed in the presence of dry tropospheric air. This allows moist static energy to accumulate and be discharged during strong intraseasonal convective events, which is consistent with the discharge/recharge paradigm. This study will examine the sensitivity of intra-seasonal variability to changes in minimum entrainment rate in the NCAR-CAM3 with the RAS scheme. Simulations using several minimum entrainment rate thresholds will be investigated. A frequency-wavenumber analysis will show the improvement of the MJO signal as minimum entrainment rate is increased. The spatial and vertical structure of MJO-like disturbances will be examined, including an analysis of the time evolution of vertical humidity distribution for each simulation. Simulated results will be compared to observed MJO events in NCEP-1 reanalysis and CMAP precipitation.

  1. Quality risk management of top spray fluidized bed process for antihypertensive drug formulation with control strategy engendered by Box-behnken experimental design space

    PubMed Central

    Mukharya, Amit; Patel, Paresh U; Shenoy, Dinesh; Chaudhary, Shivang

    2013-01-01

    Introduction: Lacidipine (LCDP) is a very low soluble and highly biovariable calcium channel blocker used in the treatment of hypertension. To increase its apparent solubility and to reduce its biovariability, solid dispersion fluid bed processing technology was explored, as it produces highly dispersible granules with a characteristic porous structure that enhances dispersibility, wettability, blend uniformity (by dissolving and spraying a solution of actives), flow ability and compressibility of granules for tableting and reducing variability by uniform drug-binder solution distribution on carrier molecules. Materials and Methods: Main object of this quality risk management (QRM) study is to provide a sophisticated “robust and rugged” Fluidized Bed Process (FBP) for the preparation of LCDP tablets with desired quality (stability) and performance (dissolution) by quality by design (QbD) concept. Results and Conclusion: This study is principally focusing on thorough mechanistic understanding of the FBP by which it is developed and scaled up with a knowledge of the critical risks involved in manufacturing process analyzed by risk assessment tools like: Qualitative Initial Risk-based Matrix Analysis (IRMA) and Quantitative Failure Mode Effective Analysis (FMEA) to identify and rank parameters with potential to have an impact on In Process/Finished Product Critical Quality Attributes (IP/FP CQAs). These Critical Process Parameters (CPPs) were further refined by DoE and MVDA to develop design space with Real Time Release Testing (RTRT) that leads to implementation of a control strategy to achieve consistent finished product quality at lab scale itself to prevent possible product failure at larger manufacturing scale. PMID:23799202

  2. Characteristics of rice husk gasification in an entrained flow reactor.

    PubMed

    Zhao, Yijun; Sun, Shaozeng; Tian, Hongming; Qian, Juan; Su, Fengming; Ling, Feng

    2009-12-01

    Experiments were performed in an entrained flow reactor to better understand the characteristics of biomass gasification. Rice husk was used in this study. Effects of the gasification temperature (700, 800, 900 and 1000 degrees C) and the equivalence ratio in the range of 0.22-0.34 on the biomass gasification and the axial gas distribution in the reactor were studied. The results showed that reactions of CnHm were less important in the gasification process except cracking reactions which occurred at higher temperature. In the oxidization zone, reactions between char and oxygen had a more prevailing role. The optimal gasification temperature of the rice husk could be above 900 degrees C, and the optimal value of ER was 0.25. The gasification process was finished in 1.42 s when the gasification temperature was above 800 degrees C. A first order kinetic model was developed for describing rice husk air gasification characteristics and the relevant kinetic parameters were determined.

  3. Development of a Cl-impregnated activated carbon for entrained-flow capture of elemental mercury.

    PubMed

    Ghorishi, S Behrooz; Keeney, Robert M; Serre, Shannon D; Gullett, Brian K; Jozewicz, Wojciech S

    2002-10-15

    Efforts to discern the role of an activated carbon's surface functional groups on the adsorption of elemental mercury (Hg0) and mercuric chloride demonstrated that chlorine (Cl) impregnation of a virgin activated carbon using dilute solutions of hydrogen chloride leads to increases (by a factor of 2-3) in fixed-bed capture of these mercury species. A commercially available activated carbon (DARCO FGD, NORITAmericas Inc. [FGD])was Cl-impregnated (Cl-FGD) [5 lb (2.3 kg) per batch] and tested for entrained-flow, short-time-scale capture of Hg0. In an entrained flow reactor, the Cl-FGD was introduced in Hg0-laden flue gases (86 ppb of Hg0) of varied compositions with gas/solid contact times of about 3-4 s, resulting in significant Hg0 removal (80-90%), compared to virgin FGD (10-15%). These levels of Hg0 removal were observed across a wide range of very low carbon-to-mercury weight ratios (1000-5000). Variation of the natural gas combustion flue gas composition, by doping with nitrogen oxides and sulfur dioxide, and the flow reactor temperature (100-200 degrees C) had minimal effects on Hg0 removal bythe Cl-FGD in these carbon-to-mercury weight ratios. These results demonstrate significant enhancement of activated carbon reactivity with minimal treatment and are applicable to combustion facilities equipped with downstream particulate matter removal such as an electrostatic precipitator.

  4. Recovery comparisons--hot nitrogen Vs steam regeneration of toxic dichloromethane from activated carbon beds in oil sands process.

    PubMed

    Ramalingam, Shivaji G; Pré, Pascaline; Giraudet, Sylvain; Le Coq, Laurence; Le Cloirec, Pierre; Baudouin, Olivier; Déchelotte, Stéphane

    2012-02-29

    The regeneration experiments of dichloromethane from activated carbon bed had been carried out by both hot nitrogen and steam to evaluate the regeneration performance and the operating cost of the regeneration step. Factorial Experimental Design (FED) tool had been implemented to optimize the temperature of nitrogen and the superficial velocity of the nitrogen to achieve maximum regeneration at an optimized operating cost. All the experimental results of adsorption step, hot nitrogen and steam regeneration step had been validated by the simulation model PROSIM. The average error percentage between the simulation and experiment based on the mass of adsorption of dichloromethane was 2.6%. The average error percentages between the simulations and experiments based on the mass of dichloromethane regenerated by nitrogen regeneration and steam regeneration were 3 and 12%, respectively. From the experiments, it had been shown that both the hot nitrogen and steam regeneration had regenerated 84% of dichloromethane. But the choice of hot nitrogen or steam regeneration depends on the regeneration time, operating costs, and purity of dichloromethane regenerated. A thorough investigation had been made about the advantages and limitations of both the hot nitrogen and steam regeneration of dichloromethane.

  5. Start-up performance of Anammox process in a fixed bed reactor (FBR) filled with honeycomb-like polypropylene carriers.

    PubMed

    Wang, Tao; Shen, Boxiong; Zhang, Sha; Wang, Zhiqiang; Tian, Li

    2016-01-01

    Novel honeycomb-like carriers, made of polypropylene, were applied to enhance biomass retention capacity so as to improve Anammox start-up performance in a fixed bed reactor (FBR). The reactor was operated for 3 months. On day 45, Anammox activity appeared. After 61 days' operation, the removal efficiencies of ammonium and nitrite were both over 91% based on 70 mg N L(-1) of the influent ammonium and influent nitrite, indicating that a remarkable Anammox activity was attained. A final specific Anammox activity of 0.12 g NH4(+)-N gVSS(-1) d(-1) was reached (VSS: volatile suspended solids). The FBR showed a good capacity for resisting shock loading and was more able to resist shock loading of nitrogen concentration than resist hydraulic shock loading. Phylogenetic analysis showed that Candidatus Brocadia anammoxidans' and Candidatus Kuenenia stuttgartiensis' were detected in the mature biofilm, and Candidatus Brocadia anammoxidans' was the dominant Anammox strain. Candidatus Kuenenia stuttgartiensis' played a positive role in the reactor performance, as it could consumed nitrite quickly and efficiently so as to avoid an adverse effect of temporary nitrite accumulation. The results showed that the honeycomb-like carriers were suitable for start-up of Anammox. PMID:27120639

  6. Disordered speech disrupts conversational entrainment: a study of acoustic-prosodic entrainment and communicative success in populations with communication challenges.

    PubMed

    Borrie, Stephanie A; Lubold, Nichola; Pon-Barry, Heather

    2015-01-01

    Conversational entrainment, a pervasive communication phenomenon in which dialogue partners adapt their behaviors to align more closely with one another, is considered essential for successful spoken interaction. While well-established in other disciplines, this phenomenon has received limited attention in the field of speech pathology and the study of communication breakdowns in clinical populations. The current study examined acoustic-prosodic entrainment, as well as a measure of communicative success, in three distinctly different dialogue groups: (i) healthy native vs. healthy native speakers (Control), (ii) healthy native vs. foreign-accented speakers (Accented), and (iii) healthy native vs. dysarthric speakers (Disordered). Dialogue group comparisons revealed significant differences in how the groups entrain on particular acoustic-prosodic features, including pitch, intensity, and jitter. Most notably, the Disordered dialogues were characterized by significantly less acoustic-prosodic entrainment than the Control dialogues. Further, a positive relationship between entrainment indices and communicative success was identified. These results suggest that the study of conversational entrainment in speech pathology will have essential implications for both scientific theory and clinical application in this domain.

  7. Disordered speech disrupts conversational entrainment: a study of acoustic-prosodic entrainment and communicative success in populations with communication challenges

    PubMed Central

    Borrie, Stephanie A.; Lubold, Nichola; Pon-Barry, Heather

    2015-01-01

    Conversational entrainment, a pervasive communication phenomenon in which dialogue partners adapt their behaviors to align more closely with one another, is considered essential for successful spoken interaction. While well-established in other disciplines, this phenomenon has received limited attention in the field of speech pathology and the study of communication breakdowns in clinical populations. The current study examined acoustic-prosodic entrainment, as well as a measure of communicative success, in three distinctly different dialogue groups: (i) healthy native vs. healthy native speakers (Control), (ii) healthy native vs. foreign-accented speakers (Accented), and (iii) healthy native vs. dysarthric speakers (Disordered). Dialogue group comparisons revealed significant differences in how the groups entrain on particular acoustic–prosodic features, including pitch, intensity, and jitter. Most notably, the Disordered dialogues were characterized by significantly less acoustic-prosodic entrainment than the Control dialogues. Further, a positive relationship between entrainment indices and communicative success was identified. These results suggest that the study of conversational entrainment in speech pathology will have essential implications for both scientific theory and clinical application in this domain. PMID:26321996

  8. Effects of ripening stage and steaming time on quality attributes of fat free banana snack obtained from drying process including fluidized bed puffing.

    PubMed

    Prachayawarakorn, Somkiat; Raikham, Chonlada; Soponronnarit, Somchart

    2016-02-01

    Healthy snacks have increasingly been interested in consumers. Puffing technique is an alternative to produce healthy snacks. Effects of ripening stage of banana and steaming time on quality of banana slices obtained from drying process including fluidized bed puffing were investigated. Bananas at the ripening stages 1 and 3 were steamed at 100 °C for 30 s up to 2 min and dried at 90 °C to moisture content of 25 % dry basis (d.b.). The samples were then puffed by fluidized bed dryer at 160 °C for 2 min and dried at the same temperature as the first stage drying. The experimental results showed that shrinkage, drying time, color, glycemic index and textural properties were affected by steaming time and ripening stage. Steaming provided more uniformity of banana color. Steaming positively or negatively affected the degree shrinkage of banana depending on the ripening stage. The banana texture in particular crispiness could be improved by the steaming for the ripening stage 1 banana whilst it did not improve for the ripening stage 3. During steaming, the C-type crystalline structure of banana starch disappeared and thus the value of glycemic index was increased. The ripening stage 1 banana was recommended for producing healthy snack in order to control glycemic response. PMID:27162374

  9. Post-treatment of anaerobically degraded azo dye Acid Red 18 using aerobic moving bed biofilm process: enhanced removal of aromatic amines.

    PubMed

    Koupaie, E Hosseini; Moghaddam, M R Alavi; Hashemi, S H

    2011-11-15

    The application of aerobic moving bed biofilm process as post-treatment of anaerobically degraded azo dye Acid Red 18 was investigated in this study. The main objective of this work was to enhance removal of anaerobically formed the dye aromatic metabolites. Three separate sequential treatment systems were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Each treatment system consisted of an anaerobic sequencing batch reactor (An-SBR) followed by an aerobic moving bed sequencing batch biofilm reactor (MB-SBBR). Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The obtained results suggested no significant difference in COD removal as well as the dye decolorization efficiency using three An-SBRs receiving different initial dye concentrations. Monitoring the dye metabolites through HPLC suggested that more than 80% of anaerobically formed 1-naphthylamine-4-sulfonate was completely removed in the aerobic biofilm reactors. Based on COD analysis results, at least 65-72% of the dye total metabolites were mineralized during the applied treatment systems. According to the measured biofilm mass and also based on respiration-inhibition test results, increasing the initial dye concentration inhibited the growth and final mass of the attached-growth biofilm in MB-SBBRs.

  10. Effect of process temperature on morphology of CNTs grown in a vertically fluidized bed reactor with Fe2O3/Al2O3 catalyst

    NASA Astrophysics Data System (ADS)

    Shukrullah, Shazia; Mohamed, Norani Muti; Shaharun, Maizatul Shima

    2015-07-01

    Carbon nanotubes (CNTs) are one of the most researched materials due to their exceptional mechanical and electrical properties. Among the various techniques, catalytic chemical vapor deposition in a fluidized bed reactor is the most promising technique for bulk production of CNTs. To meet the demand of good quality along with the bulk production of CNTs, the effect of reaction temperature on the micro structures, morphology, diameter, quality and quantity of CNTs was investigated in these studies. CNTs were synthesized at process temperature ranging from 700-850°C by catalytic decomposition of C2H4 on Fe2O3/Al2O3 catalyst a vertical fluidized bed reactor. The microstructures of the grown CNTs at different reaction temperatures were investigated by using scanning electron microscope. The results of this study depicted a positive correlation between the average diameter of CNTs and reaction temperature. Narrow diameters (35˜40 nm) of CNTs with fewer defects were found at the low and mild temperatures, in particular 800°C. At this temperature, a dynamic equilibrium between the rate of C2H4 decomposition and CNTs quantity was found due to maximum carbon diffusion over catalyst. The CNTs produced with Fe2O3/Al2O3 catalyst wer e also exhibiting high quality with relatively small mean outer diameter and fewer surface defects.

  11. The impact of aquatic animals on bedload transport in gravel-bed rivers

    NASA Astrophysics Data System (ADS)

    Johnson, M.; Rice, S. P.

    2012-12-01

    Grain-scale processes are known to have large impacts on the transport of bed material in rivers. The structure, topography and distribution of grain sizes that make up a bed, all contribute to the mobility of fluvial substrates. Animals in rivers interact with the substrate in a multitude of ways, for example, when burrowing, moving and foraging for food. Alterations to the arrangement of grains that result from these activities have a demonstrable impact on particle stability and critical entrainment stresses. This raises the intriguing possibility that aquatic fauna have large, cumulative impacts on the structure of river bed material and, consequently, on the transport of bed material. The activities of signal crayfish (Pacifastacus leniusculus), a globally important invasive crustacean, alter the arrangement of surface grains in fluvial substrates. They also construct pits and mounds across surfaces within which they shelter. These structural and topographic alterations to surfaces were quantified using repeat laser scans to create Digital Elevation Models (DEMs) before and after crayfish activity. Crayfish moved grains up to 32 mm in diameter and with a submerged weight six times that of average adult crayfish. As a result of crayfish destroying grain-scale structures, 50% more material was entrained from disturbed fluvial substrates in comparison to control surfaces that had not been exposed to crayfish. Animals can also stabilise substrates. Hydropsychid caddisfly larvae bind grains together with silk, which is spun for a variety of purposes including the creation of nets to catch organic matter from the flow. Fine gravels (2-6 mm) that were colonised by natural densities of caddisfly, required 20% increases in shear stress to be mobilised in comparison to uncolonised, control gravels. Whilst these results demonstrate the potential for animals to affect grain-scale processes, their river-scale impact needs to be assessed in field environments, in the

  12. Parameterization of a numerical 2-D debris flow model with entrainment: a case study of the Faucon catchment, Southern French Alps

    NASA Astrophysics Data System (ADS)

    Hussin, H. Y.; Luna, B. Quan; van Westen, C. J.; Christen, M.; Malet, J.-P.; van Asch, Th. W. J.

    2012-10-01

    The occurrence of debris flows has been recorded for more than a century in the European Alps, accounting for the risk to settlements and other human infrastructure that have led to death, building damage and traffic disruptions. One of the difficulties in the quantitative hazard assessment of debris flows is estimating the run-out behavior, which includes the run-out distance and the related hazard intensities like the height and velocity of a debris flow. In addition, as observed in the French Alps, the process of entrainment of material during the run-out can be 10-50 times in volume with respect to the initially mobilized mass triggered at the source area. The entrainment process is evidently an important factor that can further determine the magnitude and intensity of debris flows. Research on numerical modeling of debris flow entrainment is still ongoing and involves some difficulties. This is partly due to our lack of knowledge of the actual process of the uptake and incorporation of material and due the effect of entrainment on the final behavior of a debris flow. Therefore, it is important to model the effects of this key erosional process on the formation of run-outs and related intensities. In this study we analyzed a debris flow with high entrainment rates that occurred in 2003 at the Faucon catchment in the Barcelonnette Basin (Southern French Alps). The historic event was back-analyzed using the Voellmy rheology and an entrainment model imbedded in the RAMMS 2-D numerical modeling software. A sensitivity analysis of the rheological and entrainment parameters was carried out and the effects of modeling with entrainment on the debris flow run-out, height and velocity were assessed.

  13. Entrained phase adsorption of PCDD/F from incinerator flue gases.

    PubMed

    Everaert, K; Baeyens, J; Degrève, J

    2003-03-15

    The emission abatement of polychlorinated dioxins and furans (PCDD/F) issued from municipal solid waste incineration (MSWI) is growing in importance because of more stringent emission standards and general health concern. These substances cannot be separated by conventional gas cleanup processes. They are successfully removed through adsorption onto carbonaceous materials, and the entrained-phase injection of pulverized adsorbents in the flue gas, followed by high-efficiency separation, is widely applied. Operating conditions and results obtained in Flemish MSWIs are given. The results illustrate the excellent overall removal efficiency: the regulation limit of 0.1 ng TEO/Nm3 dry gas at 11% O2 can be achieved. Furans are adsorbed to a slightly higher extent than the dioxins. The PCDD/F removal by carbonaceous adsorbents is thereafter modeled from first principles for the contribution of both entrained-phase (eta1) and cake filtration (eta2) to the overall efficiency (etaT), with dominant parameters being the operating temperature, the dosage and activity of adsorbent, and the fraction of adsorbent in the filter cake. Application of the model equations and comparison of measured and predicted overall efficiencies for the Flemish MSWIs demonstrate the validity of the model, which enables the MSWI operators both to predict the adsorption efficiencies for combinations of major operating parameters and to assess the sensitivity of the process to varying operating conditions. Finally, some practical difficulties encountered with the entrained-phase adsorption are discussed. PMID:12680678

  14. Auditory-motor entrainment and phonological skills: precise auditory timing hypothesis (PATH)

    PubMed Central

    Tierney, Adam; Kraus, Nina

    2014-01-01

    Phonological skills are enhanced by music training, but the mechanisms enabling this cross-domain enhancement remain unknown. To explain this cross-domain transfer, we propose a precise auditory timing hypothesis (PATH) whereby entrainment practice is the core mechanism underlying enhanced phonological abilities in musicians. Both rhythmic synchronization and language skills such as consonant discrimination, detection of word and phrase boundaries, and conversational turn-taking rely on the perception of extremely fine-grained timing details in sound. Auditory-motor timing is an acoustic feature which meets all five of the pre-conditions necessary for cross-domain enhancement to occur (Patel, 2011, 2012, 2014). There is overlap between the neural networks that process timing in the context of both music and language. Entrainment to music demands more precise timing sensitivity than does language processing. Moreover, auditory-motor timing integration captures the emotion of the trainee, is repeatedly practiced, and demands focused attention. The PATH predicts that musical training emphasizing entrainment will be particularly effective in enhancing phonological skills. PMID:25505879

  15. Evidence of micro-continent entrainment during crustal accretion.

    PubMed

    Pilia, S; Rawlinson, N; Cayley, R A; Bodin, T; Musgrave, R; Reading, A M; Direen, N G; Young, M K

    2015-01-01

    Simple models involving the gradual outboard accretion of material along curvilinear subduction zones are often inconsistent with field-based evidence. A recent study using 3-D geodynamic modelling has shown that the entrainment of an exotic continental fragment within a simple subduction system can result in a complex phase of growth. Although kinematic models based on structural mapping and high-resolution gravity and magnetic maps indicate that the pre-Carboniferous Tasmanides in southeastern Australia may have been subjected to this process, to date there has been little corroboration from crustal scale geophysical imaging. Here, we apply Bayesian transdimensional tomography to ambient noise data recorded by the WOMBAT transportable seismic array to constrain a detailed (20 km resolution in some areas) 3-D shear velocity model of the crust beneath southeast Australia. We find that many of the velocity variations that emerge from our inversion support the recently developed geodynamic and kinematic models. In particular, the full thickness of the exotic continental block, responsible for orocline formation and the tectonic escape of the back arc region, is imaged here for the first time. Our seismic results provide the first direct evidence that exotic continental fragments may profoundly affect the development of an accretionary orogen. PMID:25645934

  16. Liquid Droplet Detachment and Entrainment in Microscale Flows

    NASA Astrophysics Data System (ADS)

    Hidrovo, Carlos

    2005-11-01

    In this talk we will present a first order study of liquid water detachment and entrainment into air flows in hydrophobic microchannels. Silicon based microstructures consisting of 23 mm long U-shaped channels of different geometry were used for this purpose. The structures are treated with a Molecular Vapor Deposition (MVD) process that renders them hydrophobic. Liquid water is injected through a side slot located 2/3 of the way downstream from the air channel inlet. The water entering the air channel beads up into slugs or droplets that grow in size at this injection location until they fill and flood the channel or are carried away by the air flow. The slugs/droplets dimensions at detachment are correlated against superficial gas velocity and proper dimensionless parameters are postulated and examined to compare hydrodynamic forces against surface tension. It is found that slug/droplet detachment is dominated by two main forces: pressure gradient drag, arising from confinement of a viscous flow in the channel, and inertial drag, arising from the stagnation of the air due to obstruction by the slugs/droplets. A detachment regime map is postulated based on the relative importance of these forces under different flow conditions.

  17. Evidence of micro-continent entrainment during crustal accretion.

    PubMed

    Pilia, S; Rawlinson, N; Cayley, R A; Bodin, T; Musgrave, R; Reading, A M; Direen, N G; Young, M K

    2015-02-03

    Simple models involving the gradual outboard accretion of material along curvilinear subduction zones are often inconsistent with field-based evidence. A recent study using 3-D geodynamic modelling has shown that the entrainment of an exotic continental fragment within a simple subduction system can result in a complex phase of growth. Although kinematic models based on structural mapping and high-resolution gravity and magnetic maps indicate that the pre-Carboniferous Tasmanides in southeastern Australia may have been subjected to this process, to date there has been little corroboration from crustal scale geophysical imaging. Here, we apply Bayesian transdimensional tomography to ambient noise data recorded by the WOMBAT transportable seismic array to constrain a detailed (20 km resolution in some areas) 3-D shear velocity model of the crust beneath southeast Australia. We find that many of the velocity variations that emerge from our inversion support the recently developed geodynamic and kinematic models. In particular, the full thickness of the exotic continental block, responsible for orocline formation and the tectonic escape of the back arc region, is imaged here for the first time. Our seismic results provide the first direct evidence that exotic continental fragments may profoundly affect the development of an accretionary orogen.

  18. Colour As a Signal for Entraining the Mammalian Circadian Clock

    PubMed Central

    Walmsley, Lauren; Hanna, Lydia; Mouland, Josh; Martial, Franck; West, Alexander; Smedley, Andrew R.; Bechtold, David A.; Webb, Ann R.; Lucas, Robert J.; Brown, Timothy M.

    2015-01-01

    Twilight is characterised by changes in both quantity (“irradiance”) and quality (“colour”) of light. Animals use the variation in irradiance to adjust their internal circadian clocks, aligning their behaviour and physiology with the solar cycle. However, it is currently unknown whether changes in colour also contribute to this entrainment process. Using environmental measurements, we show here that mammalian blue–yellow colour discrimination provides a more reliable method of tracking twilight progression than simply measuring irradiance. We next use electrophysiological recordings to demonstrate that neurons in the mouse suprachiasmatic circadian clock display the cone-dependent spectral opponency required to make use of this information. Thus, our data show that some clock neurons are highly sensitive to changes in spectral composition occurring over twilight and that this input dictates their response to changes in irradiance. Finally, using mice housed under photoperiods with simulated dawn/dusk transitions, we confirm that spectral changes occurring during twilight are required for appropriate circadian alignment under natural conditions. Together, these data reveal a new sensory mechanism for telling time of day that would be available to any mammalian species capable of chromatic vision. PMID:25884537

  19. Evidence of micro-continent entrainment during crustal accretion

    PubMed Central

    Pilia, S.; Rawlinson, N.; Cayley, R. A.; Bodin, T.; Musgrave, R.; Reading, A. M.; Direen, N. G.; Young, M. K.

    2015-01-01

    Simple models involving the gradual outboard accretion of material along curvilinear subduction zones are often inconsistent with field-based evidence. A recent study using 3-D geodynamic modelling has shown that the entrainment of an exotic continental fragment within a simple subduction system can result in a complex phase of growth. Although kinematic models based on structural mapping and high-resolution gravity and magnetic maps indicate that the pre-Carboniferous Tasmanides in southeastern Australia may have been subjected to this process, to date there has been little corroboration from crustal scale geophysical imaging. Here, we apply Bayesian transdimensional tomography to ambient noise data recorded by the WOMBAT transportable seismic array to constrain a detailed (20 km resolution in some areas) 3-D shear velocity model of the crust beneath southeast Australia. We find that many of the velocity variations that emerge from our inversion support the recently developed geodynamic and kinematic models. In particular, the full thickness of the exotic continental block, responsible for orocline formation and the tectonic escape of the back arc region, is imaged here for the first time. Our seismic results provide the first direct evidence that exotic continental fragments may profoundly affect the development of an accretionary orogen. PMID:25645934

  20. Colour as a signal for entraining the mammalian circadian clock.

    PubMed

    Walmsley, Lauren; Hanna, Lydia; Mouland, Josh; Martial, Franck; West, Alexander; Smedley, Andrew R; Bechtold, David A; Webb, Ann R; Lucas, Robert J; Brown, Timothy M

    2015-04-01

    Twilight is characterised by changes in both quantity ("irradiance") and quality ("colour") of light. Animals use the variation in irradiance to adjust their internal circadian clocks, aligning their behaviour and physiology with the solar cycle. However, it is currently unknown whether changes in colour also contribute to this entrainment process. Using environmental measurements, we show here that mammalian blue-yellow colour discrimination provides a more reliable method of tracking twilight progression than simply measuring irradiance. We next use electrophysiological recordings to demonstrate that neurons in the mouse suprachiasmatic circadian clock display the cone-dependent spectral opponency required to make use of this information. Thus, our data show that some clock neurons are highly sensitive to changes in spectral composition occurring over twilight and that this input dictates their response to changes in irradiance. Finally, using mice housed under photoperiods with simulated dawn/dusk transitions, we confirm that spectral changes occurring during twilight are required for appropriate circadian alignment under natural conditions. Together, these data reveal a new sensory mechanism for telling time of day that would be available to any mammalian species capable of chromatic vision.

  1. Pulse and Entrainment to Non-Isochronous Auditory Stimuli: The Case of North Indian Alap

    PubMed Central

    Will, Udo; Clayton, Martin; Wertheim, Ira; Leante, Laura; Berg, Eric

    2015-01-01

    Pulse is often understood as a feature of a (quasi-) isochronous event sequence that is picked up by an entrained subject. However, entrainment does not only occur between quasi-periodic rhythms. This paper demonstrates the expression of pulse by subjects listening to non-periodic musical stimuli and investigates the processes behind this behaviour. The stimuli are extracts from the introductory sections of North Indian (Hindustani) classical music performances (alap, jor and jhala). The first of three experiments demonstrates regular motor responses to both irregular alap and more regular jor sections: responses to alap appear related to individual spontaneous tempi, while for jor they relate to the stimulus event rate. A second experiment investigated whether subjects respond to average periodicities of the alap section, and whether their responses show phase alignment to the musical events. In the third experiment we investigated responses to a broader sample of performances, testing their relationship to spontaneous tempo, and the effect of prior experience with this music. Our results suggest an entrainment model in which pulse is understood as the experience of one’s internal periodicity: it is not necessarily linked to temporally regular, structured sensory input streams; it can arise spontaneously through the performance of repetitive motor actions, or on exposure to event sequences with rather irregular temporal structures. Greater regularity in the external event sequence leads to entrainment between motor responses and stimulus sequence, modifying subjects’ internal periodicities in such a way that they are either identical or harmonically related to each other. This can be considered as the basis for shared (rhythmic) experience and may be an important process supporting ‘social’ effects of temporally regular music. PMID:25849357

  2. Packed Bed Reactor Experiment

    NASA Video Gallery

    The purpose of the Packed Bed Reactor Experiment in low gravity is to determine how a mixture of gas and liquid flows through a packed bed in reduced gravity. A packed bed consists of a metal pipe ...

  3. Avionics test bed development plan

    NASA Technical Reports Server (NTRS)

    Harris, L. H.; Parks, J. M.; Murdock, C. R.

    1981-01-01

    A development plan for a proposed avionics test bed facility for the early investigation and evaluation of new concepts for the control of large space structures, orbiter attached flex body experiments, and orbiter enhancements is presented. A distributed data processing facility that utilizes the current laboratory resources for the test bed development is outlined. Future studies required for implementation, the management system for project control, and the baseline system configuration are defined. A background analysis of the specific hardware system for the preliminary baseline avionics test bed system is included.

  4. Improvement of hydrogen solubility and entrainment in hydrocracker feedstocks. Quarterly technical report, January 1, 1995--March 31, 1995

    SciTech Connect

    Kabadi, V.N.

    1995-07-01

    The objective of this project is to determine the conditions for the hydrogen-heavy oil feed preparation so as to optimize the yield of hydrocracking reactions. Proper contacting of hydrogen with heavy oil on the catalytic bed is necessary to improve the yields of the hydrocracking reactions. It is most desirable to have the necessary amount of hydrogen available either in the dissolved or in entrained state, so that hydrogen diffusion to the reaction site does not provide rate controlling resistance to the overall rates of hydrocracking reactions. This project proposes to measure solubility and entrainment data for hydrogen in heavy oils at conditions such as in hydrocrackers, and investigate the improvement of these properties by usage of appropriate additives. Specifically, measurements will be carried out at temperatures up to 300{degrees}C and pressures up to 120 atmospheres. Correlations for solubility and entrainment kinetics will be developed from the measured data, and a method for estimating yield of hydrocracking reactions using these correlations will be suggested. Exxon Research and Engineering Company will serve as private sector collaborator providing A&T with test samples and some technical expertise that will assure successful completion of the project. Results are presented for solubility of hydrogen in hydrocarbons and in heavy petroleum fractions. Comparison with experimental data shows good agreements. It is also demonstrated that the model is easily applied to compute solubility of hydrogen in heavy petroleum fractions with fair degree of accuracy. Detailed results are presented.

  5. Systematic approach to determination of maximum achievable capture capacity via leaching and carbonation processes for alkaline steelmaking wastes in a rotating packed bed.

    PubMed

    Pan, Shu-Yuan; Chiang, Pen-Chi; Chen, Yi-Hung; Chen, Chun-Da; Lin, Hsun-Yu; Chang, E-E

    2013-01-01

    Accelerated carbonation of basic oxygen furnace slag (BOFS) coupled with cold-rolling wastewater (CRW) was performed in a rotating packed bed (RPB) as a promising process for both CO2 fixation and wastewater treatment. The maximum achievable capture capacity (MACC) via leaching and carbonation processes for BOFS in an RPB was systematically determined throughout this study. The leaching behavior of various metal ions from the BOFS into the CRW was investigated by a kinetic model. In addition, quantitative X-ray diffraction (QXRD) using the Rietveld method was carried out to determine the process chemistry of carbonation of BOFS with CRW in an RPB. According to the QXRD results, the major mineral phases reacting with CO2 in BOFS were Ca(OH)2, Ca2(HSiO4)(OH), CaSiO3, and Ca2Fe1.04Al0.986O5. Meanwhile, the carbonation product was identified as calcite according to the observations of SEM, XEDS, and mappings. Furthermore, the MACC of the lab-scale RPB process was determined by balancing the carbonation conversion and energy consumption. In that case, the overall energy consumption, including grinding, pumping, stirring, and rotating processes, was estimated to be 707 kWh/t-CO2. It was thus concluded that CO2 capture by accelerated carbonation of BOFS could be effectively and efficiently performed by coutilizing with CRW in an RPB. PMID:24236803

  6. Systematic approach to determination of maximum achievable capture capacity via leaching and carbonation processes for alkaline steelmaking wastes in a rotating packed bed.

    PubMed

    Pan, Shu-Yuan; Chiang, Pen-Chi; Chen, Yi-Hung; Chen, Chun-Da; Lin, Hsun-Yu; Chang, E-E

    2013-01-01

    Accelerated carbonation of basic oxygen furnace slag (BOFS) coupled with cold-rolling wastewater (CRW) was performed in a rotating packed bed (RPB) as a promising process for both CO2 fixation and wastewater treatment. The maximum achievable capture capacity (MACC) via leaching and carbonation processes for BOFS in an RPB was systematically determined throughout this study. The leaching behavior of various metal ions from the BOFS into the CRW was investigated by a kinetic model. In addition, quantitative X-ray diffraction (QXRD) using the Rietveld method was carried out to determine the process chemistry of carbonation of BOFS with CRW in an RPB. According to the QXRD results, the major mineral phases reacting with CO2 in BOFS were Ca(OH)2, Ca2(HSiO4)(OH), CaSiO3, and Ca2Fe1.04Al0.986O5. Meanwhile, the carbonation product was identified as calcite according to the observations of SEM, XEDS, and mappings. Furthermore, the MACC of the lab-scale RPB process was determined by balancing the carbonation conversion and energy consumption. In that case, the overall energy consumption, including grinding, pumping, stirring, and rotating processes, was estimated to be 707 kWh/t-CO2. It was thus concluded that CO2 capture by accelerated carbonation of BOFS could be effectively and efficiently performed by coutilizing with CRW in an RPB.

  7. The Shields number is a granular bed state parameter

    NASA Astrophysics Data System (ADS)

    Church, M. A.

    2011-12-01

    The Shields number can be interpreted as a fundamental measure of the state of a granular surface under shear flow, signifying the intensity of bed material transport over the surface. The 'critical' Shields number is interpreted as a measure of the threshold condition at which individual grains begin to be entrained or, in practice, the state beyond which rare entrainment events rapidly become more common. In fact, the Shields number is a measure of the aggregate state of the granular bed that reduces to a measure of individual grain mobility only under conditions of no intergranular constraint. Hiding, imbrication and more complex structural arrangements of granular stream beds always produce some degree of constraint and, in channels beyond about 3% gradient, constraint is essential if individual grains are to remain in the channel under flows that just submerge the grain. Indirect evidence for the Shields number as a bed state parameter is available from a large number of observations. How to assign a particular critical Shields number to a given bed is, however, by no means clear. By what mechanisms do bed configurations develop that lead to grain constraint? This question poses a problem in granular mechanics in a restricted active layer or, near threshold, essentially on a rough 2D plane. Such circumstances have been much less investigated than 3D granular flows. Modification of the bed state so that individual grains become more reluctant to move has been generally characterized as 'bed settlement' but details remain almost entirely open for investigation. Differential mobility of different grain sizes and interference between mobile and static grains are important aspects of the problem.

  8. Performance of on-site pilot static granular bed reactor (SGBR) for treating dairy processing wastewater and chemical oxygen demand balance modeling under different operational conditions.

    PubMed

    Oh, Jin Hwan; Park, Jaeyoung; Ellis, Timothy G

    2015-02-01

    The performance and operational stability of a pilot-scale static granular bed reactor (SGBR) for the treatment of dairy processing wastewater were investigated under a wide range of organic and hydraulic loading rates and temperature conditions. The SGBR achieved average chemical oxygen demand (COD), biological oxygen demand (BOD), and total suspended solids (TSS)-removal efficiencies higher than 90% even at high loading rates up to 7.3 kg COD/m(3)/day, with an hydraulic retention time (HRT) of 9 h, and at low temperatures of 11 °C. The average methane yield of 0.26 L CH4/g COD(removed) was possibly affected by a high fraction of particulate COD and operation at low temperatures. The COD mass balance indicated that soluble COD was responsible for most of the methane production. The reactor showed the capacity of the methanogens to maintain their activity and withstand organic and hydraulic shock loads.

  9. Performance of on-site pilot static granular bed reactor (SGBR) for treating dairy processing wastewater and chemical oxygen demand balance modeling under different operational conditions.

    PubMed

    Oh, Jin Hwan; Park, Jaeyoung; Ellis, Timothy G

    2015-02-01

    The performance and operational stability of a pilot-scale static granular bed reactor (SGBR) for the treatment of dairy processing wastewater were investigated under a wide range of organic and hydraulic loading rates and temperature conditions. The SGBR achieved average chemical oxygen demand (COD), biological oxygen demand (BOD), and total suspended solids (TSS)-removal efficiencies higher than 90% even at high loading rates up to 7.3 kg COD/m(3)/day, with an hydraulic retention time (HRT) of 9 h, and at low temperatures of 11 °C. The average methane yield of 0.26 L CH4/g COD(removed) was possibly affected by a high fraction of particulate COD and operation at low temperatures. The COD mass balance indicated that soluble COD was responsible for most of the methane production. The reactor showed the capacity of the methanogens to maintain their activity and withstand organic and hydraulic shock loads. PMID:25164570

  10. Process for combining the regeneratorless operation of tandem super-dense riser and fluid-bed oligomerization reactors containing a zeolite oligomerization catalyst

    SciTech Connect

    Harandi, M.N.; Owen, H.

    1990-05-15

    This patent describes a catalytic process for upgrading a C{sub 2}{sup +} olefin feedstream to a heavier product stream rich in C{sub 10}{sup +} aliphatic hydrocarbons in first and second oligomerization zones. It comprises: contacting the olefin feedstream in the first zone with a finely divided medium pore size zeolite metallosilicate catalyst having a silica:alumina ratio grater than 12, and a constraint index in the range from about 1 to about 12, at a weight hourly space velocity (WHSV) sufficient to maintain a transport zone, and, then with essentially the same catalyst maintained as a fluid bed, the first zone containing riser catalyst having a higher coke content than that of catalyst in the second zone maintained in a turbulent regime.

  11. Cortical entrainment of human hypoglossal motor unit activities

    PubMed Central

    Laine, Christopher M.; Nickerson, Laura A.

    2012-01-01

    Output from the primary motor cortex contains oscillations that can have frequency-specific effects on the firing of motoneurons (MNs). Whereas much is known about the effects of oscillatory cortical drive on the output of spinal MN pools, considerably less is known about the effects on cranial motor nuclei, which govern speech/oromotor control. Here, we investigated cortical input to one such motor pool, the hypoglossal motor nucleus (HMN), which controls muscles of the tongue. We recorded intramuscular genioglossus electromyogram (EMG) and scalp EEG from healthy adult subjects performing a tongue protrusion task. Cortical entrainment of HMN population activity was assessed by measuring coherence between EEG and multiunit EMG activity. In addition, cortical entrainment of individual MN firing activity was assessed by measuring phase locking between single motor unit (SMU) action potentials and EEG oscillations. We found that cortical entrainment of multiunit activity was detectable within the 15- to 40-Hz frequency range but was inconsistent across recordings. By comparison, cortical entrainment of SMU spike timing was reliable within the same frequency range. Furthermore, this effect was found to be intermittent over time. Our study represents an important step in understanding corticomuscular synchronization in the context of human oromotor control and is the first study to document SMU entrainment by cortical oscillations in vivo. PMID:22049332

  12. Exploring the role of flood transience in coarse bed load sediment transport

    NASA Astrophysics Data System (ADS)

    Phillips, C. B.; Singer, M. B.; Hill, K. M.; Paola, C.

    2015-12-01

    The rate of bed load transport under steady flow is known to vary both spatially and temporally due to various hydrologic and granular phenomena. Grain size distributions and riverbed properties (packing, imbrication, etc.) are known to affect flux for a particular value of applied flow stress, while hydrology is mainly assumed to control the magnitude of the applied bed stress above the threshold for bed material entrainment. The prediction of bed load sediment transport in field settings is further complicated by the inherent transience in flood hydrology, but little is known about how such flood transience influences bed load flux over a range of applied bed stress. Here we investigate the role of flood transience for gravel bed load transport through controlled laboratory experiments in a 28 m long 0.5 meter wide flume. We explore transient flow as the combination of unsteady and intermittent flow, where unsteady flow varies in magnitude over a given duration, and intermittent flow is characterized by turning the flow on and off. We systematically vary these details of flood hydrographs from one experiment to the next, and monitor the bed load as it varies with water discharge in real time by measuring sediment flux and tracking particles. We find that even with a narrow unimodal grain size distribution and constant sediment supply we observe hysteresis in bed load flux, different thresholds for entrainment and distrainment for the rising and falling limbs of a flood, and a threshold of entrainment that can vary one flood hydrograph to the next. Despite these complex phenomena we find that the total bed load transported for each flood plots along a linear trend with the integrated excess stress, consistent with prior field results. These results suggest that while the effects of transient flow and the shape of the hydrograph are measurable, they are second-order compared to the integrated excess stress.

  13. Material Properties Governing Co-Current Flame Spread: The Effect of Air Entrainment

    NASA Technical Reports Server (NTRS)

    Coutin, Mickael; Rangwala, Ali S.; Torero, Jose L.; Buckley, Steven G.

    2003-01-01

    A study on the effects of lateral air entrainment on an upward spreading flame has been conducted. The fuel is a flat PMMA plate of constant length and thickness but variable width. Video images and surface temperatures have allowed establishing the progression of the pyrolyis front and on the flame stand-off distance. These measurements have been incorporated into a theoretical formulation to establish characteristic mass transfer numbers ("B" numbers). The mass transfer number is deemed as a material related parameter that could be used to assess the potential of a material to sustain co-current flame spread. The experimental results show that the theoretical formulation fails to describe heat exchange between the flame and the surface. The discrepancies seem to be associated to lateral air entrainment that lifts the flame off the surface and leads to an over estimation of the local mass transfer number. Particle Image Velocimetry (PIV) measurements are in the process of being acquired. These measurements are intended to provide insight on the effect of air entrainment on the flame stand-off distance. A brief description of the methodology to be followed is presented here.

  14. CFD modeling of entrained-flow coal gasifiers with improved physical and chemical sub-models

    SciTech Connect

    Ma, J.; Zitney, S.

    2012-01-01

    Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. While the turbulent multiphase reacting flow inside entrained-flow gasifiers has been modeled through computational fluid dynamic (CFD), the accuracy of sub-models requires further improvement. Built upon a previously developed CFD model for entrained-flow gasification, the advanced physical and chemical sub-models presented here include a moisture vaporization model with consideration of high mass transfer rate, a coal devolatilization model with more species to represent coal volatiles and heating rate effect on volatile yield, and careful selection of global gas phase reaction kinetics. The enhanced CFD model is applied to simulate two typical oxygen-blown entrained-flow configurations including a single-stage down-fired gasifier and a two-stage up-fired gasifier. The CFD results are reasonable in terms of predicted carbon conversion, syngas exit temperature, and syngas exit composition. The predicted profiles of velocity, temperature, and species mole fractions inside the entrained-flow gasifier models show trends similar to those observed in a diffusion-type flame. The predicted distributions of mole fractions of major species inside both gasifiers can be explained by the heterogeneous combustion and gasification reactions and the homogeneous gas phase reactions. It was also found that the syngas compositions at the CFD model exits are not in chemical equilibrium, indicating the kinetics for both heterogeneous and gas phase homogeneous reactions are important. Overall, the results achieved here indicate that the gasifier models reported in this paper are reliable and accurate enough to be incorporated into process/CFD co-simulations of IGCC power plants for systemwide design and optimization.

  15. Degradation and COD removal of catechol in wastewater using the catalytic ozonation process combined with the cyclic rotating-bed biological reactor.

    PubMed

    Aghapour, Ali Ahmad; Moussavi, Gholamreza; Yaghmaeian, Kamyar

    2015-07-01

    The effect of ozonation catalyzed with MgO/granular activated carbon (MgO/GAC) composite as a pretreatment process on the performance of cyclic rotating-bed biological reactor (CRBR) for the catechol removal from wastewater has been investigated. CRBR with acclimated biomasses could efficiently remove catechol and its related COD from wastewater at organic loading rate (OLR) of 7.82 kg COD/m(3).d (HRT of 9 h). Then, OLR increased to 15.64 kg COD/m(3).d (HRT of 4.5 h) and CRBR failed. Catalytic ozonation process (COP) used as a pre-treatment and could improve the performance of the failed CRBR. The overall removal efficiency of the combined process attained respective steady states of 91% and 79% for degradation and COD removal of catechol. Therefore, the combined process is more effective in degradation and COD removal of catechol; it is also a viable alternative for upgrading industrial wastewater treatment plant.

  16. Potent social synchronization can override photic entrainment of circadian rhythms.

    PubMed

    Fuchikawa, Taro; Eban-Rothschild, Ada; Nagari, Moshe; Shemesh, Yair; Bloch, Guy

    2016-01-01

    Circadian rhythms in behaviour and physiology are important for animal health and survival. Studies with individually isolated animals in the laboratory have consistently emphasized the dominant role of light for the entrainment of circadian rhythms to relevant environmental cycles. Although in nature interactions with conspecifics are functionally significant, social signals are typically not considered important time-givers for the animal circadian clock. Our results challenge this view. By studying honeybees in an ecologically relevant context and using a massive data set, we demonstrate that social entrainment can be potent, may act without direct contact with other individuals and does not rely on gating the exposure to light. We show for the first time that social time cues stably entrain the clock, even in animals experiencing conflicting photic and social environmental cycles. These findings add to the growing appreciation for the importance of studying circadian rhythms in ecologically relevant contexts. PMID:27210069

  17. Potent social synchronization can override photic entrainment of circadian rhythms.

    PubMed

    Fuchikawa, Taro; Eban-Rothschild, Ada; Nagari, Moshe; Shemesh, Yair; Bloch, Guy

    2016-01-01

    Circadian rhythms in behaviour and physiology are important for animal health and survival. Studies with individually isolated animals in the laboratory have consistently emphasized the dominant role of light for the entrainment of circadian rhythms to relevant environmental cycles. Although in nature interactions with conspecifics are functionally significant, social signals are typically not considered important time-givers for the animal circadian clock. Our results challenge this view. By studying honeybees in an ecologically relevant context and using a massive data set, we demonstrate that social entrainment can be potent, may act without direct contact with other individuals and does not rely on gating the exposure to light. We show for the first time that social time cues stably entrain the clock, even in animals experiencing conflicting photic and social environmental cycles. These findings add to the growing appreciation for the importance of studying circadian rhythms in ecologically relevant contexts.

  18. Potent social synchronization can override photic entrainment of circadian rhythms

    PubMed Central

    Fuchikawa, Taro; Eban-Rothschild, Ada; Nagari, Moshe; Shemesh, Yair; Bloch, Guy

    2016-01-01

    Circadian rhythms in behaviour and physiology are important for animal health and survival. Studies with individually isolated animals in the laboratory have consistently emphasized the dominant role of light for the entrainment of circadian rhythms to relevant environmental cycles. Although in nature interactions with conspecifics are functionally significant, social signals are typically not considered important time-givers for the animal circadian clock. Our results challenge this view. By studying honeybees in an ecologically relevant context and using a massive data set, we demonstrate that social entrainment can be potent, may act without direct contact with other individuals and does not rely on gating the exposure to light. We show for the first time that social time cues stably entrain the clock, even in animals experiencing conflicting photic and social environmental cycles. These findings add to the growing appreciation for the importance of studying circadian rhythms in ecologically relevant contexts. PMID:27210069

  19. Dispersal and air entrainment in unconfined dilute pyroclastic density currents

    NASA Astrophysics Data System (ADS)

    Andrews, Benjamin J.

    2014-09-01

    Unconfined scaled laboratory experiments show that 3D structures control the behavior of dilute pyroclastic density currents (PDCs) during and after liftoff. Experiments comprise heated and ambient temperature 20 μm talc powder turbulently suspended in air to form density currents within an unobstructed 8.5 × 6 × 2.6-m chamber. Comparisons of Richardson, thermal Richardson, Froude, Stokes, and settling numbers and buoyant thermal to kinetic energy densities show good agreement between experimental currents and dilute PDCs. The experimental Reynolds numbers are lower than those of PDCs, but the experiments are fully turbulent; thus, the large-scale dynamics are similar between the two systems. High-frequency, simultaneous observation in three orthogonal planes shows that the currents behave very differently than previous 2D (i.e., confined) currents. Specifically, whereas ambient temperature currents show radial dispersal patterns, buoyancy reversal, and liftoff of heated currents focuses dispersal along narrow axes beneath the rising plumes. The aspect ratios, defined as the current length divided by a characteristic width, are typically 2.5-3.5 in heated currents and 1.5-2.5 in ambient temperature currents, reflecting differences in dispersal between the two types of currents. Mechanisms of air entrainment differ greatly between the two currents: entrainment occurs primarily behind the heads and through the upper margins of ambient temperature currents, but heated currents entrain air through their lateral margins. That lateral entrainment is much more efficient than the vertical entrainment, >0.5 compared to ˜0.1, where entrainment is defined as the ratio of cross-stream to streamwise velocity. These experiments suggest that generation of coignimbrite plumes should focus PDCs along narrow transport axes, resulting in elongate rather than radial deposits.

  20. Process and technological aspects of municipal solid waste gasification. A review.

    PubMed

    Arena, Umberto

    2012-04-01

    The paper proposes a critical assessment of municipal solid waste gasification today, starting from basic aspects of the process (process types and steps, operating and performance parameters) and arriving to a comparative analysis of the reactors (fixed bed, fluidized bed, entrained bed, vertical shaft, moving grate furnace, rotary kiln, plasma reactor) as well as of the possible plant configurations (heat gasifier and power gasifier) and the environmental performances of the main commercially available gasifiers for municipal solid wastes. The analysis indicates that gasification is a technically viable option for the solid waste conversion, including residual waste from separate collection of municipal solid waste. It is able to meet existing emission limits and can have a remarkable effect on reduction of landfill disposal option.

  1. Large-scale network-level processes during entrainment

    PubMed Central

    Lithari, Chrysa; Sánchez-García, Carolina; Ruhnau, Philipp; Weisz, Nathan

    2016-01-01

    Visual rhythmic stimulation evokes a robust power increase exactly at the stimulation frequency, the so-called steady-state response (SSR). Localization of visual SSRs normally shows a very focal modulation of power in visual cortex and led to the treatment and interpretation of SSRs as a local phenomenon. Given the brain network dynamics, we hypothesized that SSRs have additional large-scale effects on the brain functional network that can be revealed by means of graph theory. We used rhythmic visual stimulation at a range of frequencies (4–30 Hz), recorded MEG and investigated source level connectivity across the whole brain. Using graph theoretical measures we observed a frequency-unspecific reduction of global density in the alpha band “disconnecting” visual cortex from the rest of the network. Also, a frequency-specific increase of connectivity between occipital cortex and precuneus was found at the stimulation frequency that exhibited the highest resonance (30 Hz). In conclusion, we showed that SSRs dynamically re-organized the brain functional network. These large-scale effects should be taken into account not only when attempting to explain the nature of SSRs, but also when used in various experimental designs. PMID:26835557

  2. Large-scale network-level processes during entrainment.

    PubMed

    Lithari, Chrysa; Sánchez-García, Carolina; Ruhnau, Philipp; Weisz, Nathan

    2016-03-15

    Visual rhythmic stimulation evokes a robust power increase exactly at the stimulation frequency, the so-called steady-state response (SSR). Localization of visual SSRs normally shows a very focal modulation of power in visual cortex and led to the treatment and interpretation of SSRs as a local phenomenon. Given the brain network dynamics, we hypothesized that SSRs have additional large-scale effects on the brain functional network that can be revealed by means of graph theory. We used rhythmic visual stimulation at a range of frequencies (4-30 Hz), recorded MEG and investigated source level connectivity across the whole brain. Using graph theoretical measures we observed a frequency-unspecific reduction of global density in the alpha band "disconnecting" visual cortex from the rest of the network. Also, a frequency-specific increase of connectivity between occipital cortex and precuneus was found at the stimulation frequency that exhibited the highest resonance (30 Hz). In conclusion, we showed that SSRs dynamically re-organized the brain functional network. These large-scale effects should be taken into account not only when attempting to explain the nature of SSRs, but also when used in various experimental designs. PMID:26835557

  3. Novel Magnetically Fluidized Bed Reactor Development for the Looping Process: Coal to Hydrogen Production R&D

    SciTech Connect

    Mei, Renwei; Hahn, David; Klausner, James; Petrasch, Jorg; Mehdizadeh, Ayyoub; Allen, Kyle; Rahmatian, Nima; Stehle, Richard; Bobek, Mike; Al-Raqom, Fotouh; Greek, Ben; Li, Like; Chen, Chen; Singh, Abhishek; Takagi, Midori; Barde, Amey; Nili, Saman

    2013-09-30

    The coal to hydrogen project utilizes the iron/iron oxide looping process to produce high purity hydrogen. The input energy for the process is provided by syngas coming from gasification process of coal. The reaction pathways for this process have been studied and favorable conditions for energy efficient operation have been identified. The Magnetically Stabilized Porous Structure (MSPS) is invented. It is fabricated from iron and silica particles and its repeatable high performance has been demonstrated through many experiments under various conditions in thermogravimetric analyzer, a lab-scale reactor, and a large scale reactor. The chemical reaction kinetics for both oxidation and reduction steps has been investigated thoroughly inside MSPS as well as on the surface of very smooth iron rod. Hydrogen, CO, and syngas have been tested individually as the reducing agent in reduction step and their performance is compared. Syngas is found to be the most pragmatic reducing agent for the two-step water splitting process. The transport properties of MSPS including porosity, permeability, and effective thermal conductivity are determined based on high resolution 3D CT x-ray images obtained at Argonne National Laboratory and pore-level simulations using a lattice Boltzmann Equation (LBE)-based mesoscopic model developed during this investigation. The results of those measurements and simulations provide necessary inputs to the development of a reliable volume-averaging-based continuum model that is used to simulate the dynamics of the redox process in MSPS. Extensive efforts have been devoted to simulate the redox process in MSPS by developing a continuum model consist of various modules for conductive and radiative heat transfer, fluid flow, species transport, and reaction kinetics. Both the Lagrangian and Eulerian approaches for species transport of chemically reacting flow in porous media have been investigated and verified numerically. Both approaches lead to correct

  4. In-line spatial filtering velocimetry for particle size and film thickness determination in fluidized-bed pellet coating processes.

    PubMed

    Folttmann, Friederike; Knop, Klaus; Kleinebudde, Peter; Pein, Miriam

    2014-11-01

    A spatial filtering velocimetry (SFV) probe was applied to monitor the increase in particle size during pellet Wurster coating processes in-line. Accuracy of the in-line obtained pellet sizes was proven by at-line performed digital image analysis (DIA). Regarding particle growth, high conformity between both analytical methods (SFV/DIA) was examined for different coating processes. The influence of ring buffer size and the process of filling the buffer were investigated. With buffer sizes of 30,000-50,000 particles best results were obtained in this study. Investigated process parameters, such as inlet air volume and spray rate, had different effects on the impact of the SFV probe. While the particle rate (the number of particles detected by the SVF probe per second) was highly dependent on the inlet air volume, different spray rates of up to ・}1 g/min did not affect the detected particle growth. Artefacts and delays in SFV particle sizing appeared especially at the beginning of the coating processes. The slope of the particle growth during the final spraying period was therefore used to determine coating thickness.

  5. Updraft Fixed Bed Gasification Aspen Plus Model

    SciTech Connect

    2007-09-27

    The updraft fixed bed gasification model provides predictive modeling capabilities for updraft fixed bed gasifiers, when devolatilization data is available. The fixed bed model is constructed using Aspen Plus, process modeling software, coupled with a FORTRAN user kinetic subroutine. Current updraft gasification models created in Aspen Plus have limited predictive capabilities and must be "tuned" to reflect a generalized gas composition as specified in literature or by the gasifier manufacturer. This limits the applicability of the process model.

  6. Wind profiler mixing depth and entrainment measurements with chemical applications

    SciTech Connect

    Angevine, W.M.; Trainer, M.; Parrish, D.D.; Buhr, M.P.; Fehsenfeld, F.C.; Kok, G.L.

    1994-12-31

    Wind profiling radars operating at 915 MHz have been present at a number of regional air quality studies. The profilers can provide a continuous, accurate record of the depth of the convective mixed layer with good time resolution. Profilers also provide information about entrainment at the boundary layer top. Mixing depth data from several days of the Rural Oxidants in the Southern Environment II (ROSE II) study in Alabama in June, 1992 are presented. For several cases, chemical measurements from aircraft and ground-based instruments are shown to correspond to mixing depth and entrainment zone behavior observed by the profiler.

  7. Fluctuations of a receding contact line near the entrainment transition

    NASA Astrophysics Data System (ADS)

    Bico, Jose; Delon, Giles; Fermigier, Marc

    2004-11-01

    We study experimentally the fluctuations of a contact line receding on a plane solid substrate. The contact line is perturbed by localized defects and we follow the relaxation of perturbations induced by these defects, as a function of the mean contact line speed and wavelengths characteristic of the perturbations. We compare our results with theoretical predictions by Golestanian and Raphael showing a divergence of the relaxation time at the entrainment transition (when the receding velocity exceeds a critical value, the liquid is entrained by the solid).

  8. Evidence for Little Shallow Entrainment in Starting Mantle Plumes

    NASA Astrophysics Data System (ADS)

    Lohmann, F. C.; Phipps Morgan, J.; Hort, M.

    2005-12-01

    Basalts from intraplate or hotspot ocean islands show distinct geochemical signatures. Their diversity in composition is generally believed to result from the upwelling plume entraining shallow mantle material during ascent, while potentially also entraining other deep regions of the mantle. Here we present results from analogue laboratory experiments and numerical modelling that there is evidence for little shallow entrainment into ascending mantle plumes, i.e. most of the plume signature is inherited from the source. We conducted laboratory experiments using glucose syrup contaminated with glass beads to visualize fluid flow and origin. The plume is initiated by heating from below or by injecting hot, uncontaminated syrup. Particle movement is captured by a CCD camera. In our numerical experiments we solve the Stokes equations for a viscous fluid at infinite Prandtl number with passive tracer particles being used to track fluid flow and entrainment rates, simulating laboratory as well as mantle conditions. In both analogue experiments and numerical models we observe the classical plume structure being embedded in a `sheath' of material from the plume source region that retains little of the original temperature anomaly of the plume source. Yet, this sheath ascends in the `slipstream' of the plume at speeds close to the ascent speed of the plume head, and effectively prevents the entrainment of surrounding material into the plume head or plume tail. We find that the source region is most effectively sampled by an ascending plume and that compositional variations in the source region are preserved during plume ascent. The plume center and plume sheath combined are composed of up to 85% source material. However, there is also evidence of significant entrainment of up to 30% of surrounding material into the outer layers of the plume sheath. Entrainment rates are found to be influenced by mantle composition and structure, with the radial viscosity profile of the

  9. A one-stage system with partial nitritation and anammox processes in the moving-bed biofilm reactor.

    PubMed

    Szatkowska, B; Cema, G; Plaza, E; Trela, J; Hultman, B

    2007-01-01

    The ability of bacterial cultures to create biofilm brings a possibility to enhance biological wastewater treatment efficiency. Moreover, the ability of Anammox and Nitrosomonas species to grow within the same biofilm layer enabled a one-stage system for nitrogen removal to be designed. Such a system, with Kaldnes rings as carriers for biofilm growth, was tested in a technical pilot plant scale (2.1 m(3)) at the Himmerfjärden Waste Water Treatment Plant (WWTP) in the Stockholm region. The system was directly supplied with supernatant originating from dewatering of digested sludge containing high ammonium concentrations. Nearly 1-year of operational data showed that during the partial nitritation/Anammox process, alkalinity was utilised parallel to ammonium removal. The process resulted in a small pH drop, and its relationship with conductivity was found. The nitrogen removal rate for the whole period oscillated around 1.5g N m(-2)d(-1) with a maximum value equal to 1.9 g N m(-2)d(-1). Parallel to the pilot plant experiment, a series of batch tests were run to investigate the influence on removal rates of different dissolved oxygen conditions and addition of nitrite. The highest nitrogen removal rate (5.2g N m(-2)2d(-1)) in batch tests was obtained when the Anammox process was stimulated by the addition of nitrite. In the simultaneous partial nitritation and Anammox process, the partial nitritation was the rate-limiting step. PMID:17546965

  10. On simulation of transfer processes in the freeboard region of a steam-generator furnace with a circulating fluidized bed

    SciTech Connect

    B.B. Rokhman

    2006-01-15

    A semiempirical, stationary, two-zone model of transfer processes in the freeboard region of a reactor with a circulating boiling layer has been constructed. The features of the aerodynamics, heat and mass transfer, and combustion of anthracite culm in the core and near-wall ring region of a flow in a KFS-0.2 pilot plant have been investigated in detail.

  11. Effects of Powder Attributes and Laser Powder Bed Fusion (L-PBF) Process Conditions on the Densification and Mechanical Properties of 17-4 PH Stainless Steel

    NASA Astrophysics Data System (ADS)

    Irrinki, Harish; Dexter, Michael; Barmore, Brenton; Enneti, Ravi; Pasebani, Somayeh; Badwe, Sunil; Stitzel, Jason; Malhotra, Rajiv; Atre, Sundar V.

    2016-03-01

    The effects of powders attributes (shape and size distribution) and critical processing conditions (energy density) on the densification and mechanical properties of laser powder bed fusion (L-PBF) 17-4 PH stainless steel were studied using four types of powders. The % theoretical density, ultimate tensile strength and hardness of both water- and gas-atomized powders increased with increased energy density. Gas-atomized powders showed superior densification and mechanical properties when processed at low energy densities. However, the % theoretical density and mechanical properties of water-atomized powders were comparable to gas-atomized powders when sintered at a high energy density of 104 J/mm3. An important result of this study was that, even at high % theoretical density (97% ± 1%), the properties of as-printed parts could vary over a relatively large range (UTS: 500-1100 MPa; hardness: 25-39 HRC; elongation: 10-25%) depending on powder characteristics and process conditions. The results also demonstrate the feasibility of using relatively inexpensive water-atomized powders as starting raw material instead of the typically used gas-atomized powders to fabricate parts using L-PBF techniques by sintering at high energy densities.

  12. Guidelines for collecting and processing samples of stream bed sediment for analysis of trace elements and organic contaminants for the National Water-Quality Assessment Program

    USGS Publications Warehouse

    Shelton, Larry R.; Capel, Paul D.

    1994-01-01

    A major component of the U.S. Geological Survey's National Water-Quality Assessment program is to assess the occurrence and distribution of trace elements and organic contaminants in streams. The first phase of the strategy for the assessment is to analyze samples of bed sediments from depositional zones. Fine-grained particles deposited in these zones are natural accumulators of trace elements and hydrophobic organic compounds. For the information to be comparable among studies in many different parts of the Nation, strategies for selecting stream sites and depositional zones are critical. Fine-grained surficial sediments are obtained from several depositional zones within a stream reach and composited to yield a sample representing average conditions. Sample collection and processing must be done consistently and by procedures specifically designed to separate the fine material into fractions that yield uncontaminated samples for trace-level analytes in the laboratory. Special coring samplers and other instruments made of Teflon are used for collection. Samples are processed through a 2.0-millimeter stainless-steel mesh sieve for organic contaminate analysis and a 63-micrometer nylon-cloth sieve for trace-element analysis. Quality assurance is maintained by strict collection and processing procedures, duplicate samplings, and a rigid cleaning procedure.

  13. Fluid bed oligomerization of olefins

    SciTech Connect

    Harandi, M.N.; Owens, H.

    1991-08-27

    This patent describes a continuous process for upgrading lower olefins to increase gasoline yield and ease of LPG recovery. It comprises separating a C{sub 2}-C{sub 4} cracked olefinic gas into a primary overhead stream containing C{sub 2} hydrocarbons having at least about 10% ethene and a secondary stream comprising a major amount of C{sub 3}-c{sub 4} olefinic hydrocarbons; adding the primary stream containing C{sub 2} hydrocarbons to a primary fluidized reaction zone comprising solid crystalline zeolite catalyst particles in a reactor bed operating under high severity conditions; adding the secondary stream comprising C{sub 3}-C{sub 4} olefinic hydrocarbons to a secondary fluidized bed reaction zone comprising solid crystalline zeolite catalyst particles in a reactor bed operating under turbulent regime low severity conditions; and withdrawing a portion of partially deactivated catalyst particles from the primary high severity fluidized bed reaction zone.

  14. CFD modeling of commercial-scale entrained-flow coal gasifiers

    SciTech Connect

    Ma, J.; Zitney, S.

    2012-01-01

    Optimization of an advanced coal-fired integrated gasification combined cycle system requires an accurate numerical prediction of gasifier performance. Computational fluid dynamics (CFD) has been used to model the turbulent multiphase reacting flow inside commercial-scale entrained-flow coal gasifiers. Due to the complexity of the physical and chemical processes involved, the accuracy of sub-models requires further improvement. Built upon a previously developed CFD model for entrained-flow gasification, the advanced physical and chemical sub-models presented in this paper include a moisture vaporization model with consideration of high mass transfer rate and a coal devolatilization model with more species to represent coal volatiles and the heating rate effect on volatile yield. The global gas phase reaction kinetics is also carefully selected. To predict a reasonable peak temperature of the coal/O{sub 2} flame inside an entrained-flow gasifier, the reserve reaction of H{sub 2} oxidation is included in the gas phase reaction model. The enhanced CFD model is applied to simulate two typical commercial-scale oxygen-blown entrained-flow configurations including a single-stage down-fired gasifier and a two-stage up-fired gasifier. The CFD results are reasonable in terms of predicted carbon conversion, syngas exit temperature, and syngas exit composition. The predicted profiles of velocity, temperature, and species mole fractions inside the entrained-flow gasifier models show trends similar to those observed in a diffusion-type flame. The predicted distributions of mole fractions of major species inside both gasifiers can be explained by the heterogeneous combustion and gasification reactions and the homogeneous gas phase reactions. It was also found that the syngas compositions at the CFD model exits are not in chemical equilibrium, indicating the kinetics for both heterogeneous and gas phase homogeneous reactions are important. Overall, the results achieved here

  15. K Basin Sludge Conditioning Process Testing Project Results from Test 4, ''Acid Digestion of Mixed-Bed Ion Exchange Resin''

    SciTech Connect

    Pool, K.H.; Delegard, C.H.; Schmidt, A.J.; Thornton, B.M.; Silvers, K.L.

    1999-04-02

    Approximately 73 m{sup 3} of heterogeneous solid material, ''sludge,'' (upper bound estimate, Packer 1997) have accumulated at the bottom of the K Basins in the 100 K Area of the Hanford Site. This sludge is a mixture of spent fuel element corrosion products, ion exchange materials (organic and inorganic), graphite-based gasket materials, iron and aluminum metal corrosion products, sand, and debris (Makenas et al. 1996, 1997). In addition, small amounts of polychlorinated biphenyls (PCBs) have been found. Ultimately, it is planned to transfer the K Basins sludge to the Hanford double shell tanks (DSTs). The Hanford Spent Nuclear Fuel (HSNF) project has conducted a number of evaluations to examine technology and processing alternatives to pretreat K Basin sludge to meet storage and disposal requirements. From these evaluations, chemical pretreatment has been selected to address criticality issues, reactivity, and the destruction or removal of PCBs before the K Basin sludge can be transferred to the DSTs. Chemical pretreatment, referred to as the K Basin sludge conditioning process, includes nitric acid dissolution of the sludge (with removal of acid insoluble solids), neutrons absorber addition, neutralization, and reprecipitation. Laboratory testing is being conducted by the Pacific Northwest National Laboratory (PNNL) to provide data necessary to develop the sludge conditioning process.

  16. Parameterization of sheared entrainment in a well-developed CBL. Part II: A simple model for predicting the growth rate of the CBL

    NASA Astrophysics Data System (ADS)

    Liu, Peng; Sun, Jianning; Shen, Lidu

    2016-10-01

    Following the parameterization of sheared entrainment obtained in the companion paper, Liu et al. (2016), the present study aims to further investigate the characteristics of entrainment, and develop a simple model for predicting the growth rate of a well-developed and sheared CBL. The relative stratification, defined as the ratio of the stratification in the free atmosphere to that in the entrainment zone, is found to be a function of entrainment flux ratio ( A e). This leads to a simple expression of the entrainment rate, in which A e needs to be parameterized. According to the results in Liu et al. (2016), A e can be simply expressed as the ratio of the convective velocity scale in the sheared CBL to that in the shear-free CBL. The parameterization of the convective velocity scale in the sheared CBL is obtained by analytically solving the bulk model with several assumptions and approximations. Results indicate that the entrainment process is influenced by the dynamic effect, the interaction between mean shear and environmental stratification, and one other term that includes the Coriolis effect. These three parameterizations constitute a simple model for predicting the growth rate of a well-developed and sheared CBL. This model is validated by outputs of LESs, and the results show that it performs satisfactorily. Compared with bulk models, this model does not need to solve a set of equations for the CBL. It is more convenient to apply in numerical models.

  17. Finial Scientific/Technical Report: Application of a Circulating Fluidized Bed Process for the Chemical Looping Combustion of Solid Fuel

    SciTech Connect

    Dr. Wei-Ping Pan; Dr. John T. Riley

    2005-10-10

    Chemical Looping Combustion is a novel combustion technology for the inherent separation of the greenhouse gas, CO{sub 2}. In 1983, Richter and Knoche proposed reversible combustion, which utilized both the oxidation and reduction of metal. Metal associated with its oxidized form as an oxygen carrier was circulated between two reactors--oxidizer and reducer. In the reducer, the solid oxygen carrier reacts with the fuel to produce CO{sub 2}, H{sub 2}O and elemental metal only. Pure CO{sub 2} will be obtained in the exit gas stream from the reducer after H{sub 2}O is condensed. The pure CO{sub 2} is ready for subsequent sequestration. In the oxidizer, the elemental metal reacts with air to form metal oxide and separate oxygen from nitrogen. Only nitrogen and some unused oxygen are emitted from the oxidizer. The advantage of CLC compared to normal combustion is that CO{sub 2} is not diluted with nitrogen but obtained in a relatively pure form without any energy needed for separation. In addition to the energy-free purification of CO{sub 2}, the CLC process also provides two other benefits. First, NO{sub x} formation can be largely eliminated. Secondly, the thermal efficiency of a CLC system is very high. Presently, the CLC process has only been used with natural gas. An oxygen carrier based on an energy balance analysis and thermodynamics analysis was selected. Copper (Cu) seems to be the best choice for the CLC system for solid fuels. From this project, the mechanisms of CuO reduction by solid fuels may be as follows: (1) If pyrolysis products of solid fuels are available, reduction of CuO could start at about 400 C or less. (2) If pyrolysis products of solid fuels are unavailable and the reduction temperature is lower, reduction of CuO could occur at an onset temperature of about 500 C, char gasification reactivity in CO{sub 2} was lower at lower temperatures. (3) If pyrolysis products of solid fuels are unavailable and the reduction temperature is higher than 750 C

  18. Design, fabrication, operation and Aspen simulation of oil shale pyrolysis and biomass gasification process using a moving bed downdraft reactor

    NASA Astrophysics Data System (ADS)

    Golpour, Hassan

    Energy is the major facilitator of the modern life. Every developed and developing economy requires access to advanced sources of energy to support its growth and prosperity. Declining worldwide crude oil reserves and increasing energy needs has focused attention on developing existing unconventional fossil fuels like oil shale and renewable resources such as biomass. Sustainable, renewable and reliable resources of domestically produced biomass comparing to wind and solar energy is a sensible motivation to establish a small-scale power plant using biomass as feed to supply electricity demand and heat for rural development. The work in Paper I focuses on the possibility of water pollution from spent oil shale which should be studied before any significant commercial production is attempted. In Paper II, the proposed Aspen models for oil shale pyrolysis is to identify the key process parameters for the reactor and optimize the rate of production of syncrude from oil shale. The work in Paper III focuses on (1) Design and operation of a vertical downdraft reactor, (2) Establishing an optimum operating methodology and parameters to maximize syngas production through process testing. Finally in Paper IV, a proposed Aspen model for biomass gasification simulates a real biomass gasification system discussed in Paper III.

  19. Coenzyme Q(10) production by immobilized Sphingomonas sp. ZUTE03 via a conversion-extraction coupled process in a three-phase fluidized bed reactor.

    PubMed

    Qiu, Lequan; Ding, Hanbing; Wang, Weijian; Kong, Zhuoyi; Li, Xuanzhen; Shi, Yuping; Zhong, Weihong

    2012-02-10

    A three-phase fluidized bed reactor (TPFBR) was designed to evaluate the potential of CoQ(10) production by gel-entrapped Sphingomonas sp. ZUTE03 via a conversion-extract coupled process. In the reactor, the CoQ(10) yield reached 46.99 mg/L after 8 h of conversion; a high-level yield of about 45 mg/L was maintained even after 15 repetitions (8 h/batch). To fully utilize the residual precursor (para-hydroxybenzoic acid, PHB) in the aqueous phase, the organic phase was replaced with new solution containing 70 mg/L solanesol for each 8 h batch. The CoQ(10) yield of each batch was maintained at a level of about 43 mg/L until the PHB ran out. When solid solanesol was fed to the organic phase for every 8 h batch, CoQ(10) could accumulate and reach a yield of 171.52 mg/L. When solid solanesol and PHB were fed to the conversion system after every 8 h batch, the CoQ(10) yield reached 441.65 mg/L in the organic phase after 20 repetitions, suggesting that the conversion-extract coupled process could enhance CoQ(10) production in the TPFBR.

  20. Lexical Entrainment and Lexical Differentiation in Reference Phrase Choice

    ERIC Educational Resources Information Center

    Van Der Wege, Mija M.

    2009-01-01

    Speakers reuse prior references to objects when choosing reference phrases, a phenomenon known as lexical entrainment. One explanation is that speakers want to maintain a set of previously established referential precedents. Speakers may also contrast any new referents against this previously established set, thereby avoiding applying the same…

  1. Suppression of competing speech through entrainment of cortical oscillations.

    PubMed

    Horton, Cort; D'Zmura, Michael; Srinivasan, Ramesh

    2013-06-01

    People are highly skilled at attending to one speaker in the presence of competitors, but the neural mechanisms supporting this remain unclear. Recent studies have argued that the auditory system enhances the gain of a speech stream relative to competitors by entraining (or "phase-locking") to the rhythmic structure in its acoustic envelope, thus ensuring that syllables arrive during periods of high neuronal excitability. We hypothesized that such a mechanism could also suppress a competing speech stream by ensuring that syllables arrive during periods of low neuronal excitability. To test this, we analyzed high-density EEG recorded from human adults while they attended to one of two competing, naturalistic speech streams. By calculating the cross-correlation between the EEG channels and the speech envelopes, we found evidence of entrainment to the attended speech's acoustic envelope as well as weaker yet significant entrainment to the unattended speech's envelope. An independent component analysis (ICA) decomposition of the data revealed sources in the posterior temporal cortices that displayed robust correlations to both the attended and unattended envelopes. Critically, in these components the signs of the correlations when attended were opposite those when unattended, consistent with the hypothesized entrainment-based suppressive mechanism. PMID:23515789

  2. Attempted entrainment of circus movement tachycardias by ventricular stimulation.

    PubMed

    Saoudi, N C; Castellanos, A; Zaman, L; Portillo, B; Schwartz, A; Myerburg, R J

    1986-01-01

    Entrainment was attempted while pacing the right ventricle in 12 patients with circus movement tachycardias. At the onset of stimulation eight patients had short episodes of intraventricular and atrioventricular dissociation during which the paced impulses activated the various ventricular recording sites (right and left), but did not reach the atria. The latter occurred because the ventricular electrograms were recorded from parts of the ventricles which were not essential components of the reentry circuit. Relatively long (greater than 5 s) runs of entrainment were not possible in any case because of the relatively prompt termination of the tachycardias. Whereas in three patients this was due to the abrupt appearance of retrograde block in the accessory pathway, in nine patients it happened when the sequential, anterograde and retrograde, penetration of the AV node resulted in AV nodal block of the subsequent, reentering atrial impulse. The findings in this study showed that, with the methodology used, entrainment of circus movement tachycardias by ventricular stimulation had to be defined conceptually, by the fulfillment of requirements which did not include its occurrence for at least 5 seconds. Furthermore, the results also suggested that entrainment and tachycardia termination were best demonstrated by a technique which allowed the emission of the first stimulus in a constant (late) moment of the cycle, with deliverance of one additional stimulus at the same cycle length in successive pacing runs.

  3. Queueing-Based Synchronization and Entrainment for Synthetic Gene Oscillators

    NASA Astrophysics Data System (ADS)

    Mather, William; Butzin, Nicholas; Hochendoner, Philip; Ogle, Curtis

    Synthetic gene oscillators have been a major focus of synthetic biology research since the beginning of the field 15 years ago. They have proven to be useful both for biotechnological applications as well as a testing ground to significantly develop our understanding of the design principles behind synthetic and native gene oscillators. In particular, the principles governing synchronization and entrainment of biological oscillators have been explored using a synthetic biology approach. Our work combines experimental and theoretical approaches to specifically investigate how a bottleneck for protein degradation, which is present in most if not all existing synthetic oscillators, can be leveraged to robustly synchronize and entrain biological oscillators. We use both the terminology and mathematical tools of queueing theory to intuitively explain the role of this bottleneck in both synchronization and entrainment, which extends prior work demonstrating the usefulness of queueing theory in synthetic and native gene circuits. We conclude with an investigation of how synchronization and entrainment may be sensitive to the presence of multiple proteolytic pathways in a cell that couple weakly through crosstalk. This work was supported by NSF Grant #1330180.

  4. Evaluation of a debris-flow entrainment model on field cases from the Swiss Alps

    NASA Astrophysics Data System (ADS)

    Frank, Florian; McArdell, Brian; Huggel, Christian; Vieli, Andreas

    2015-04-01

    Debris-flow erosion is an important process for shaping the landscape and highly relevant in terms of hazard due to the potential of substantially increasing the flow magnitude. Here we describe the development and testing of a model for the erosion of sediment deposits by entrainment. The model is based on a generalization of field data from the Illgraben torrent channel in Switzerland, where the slope of the channel on the fan varies between 8% and 10%. The entrainment model predicts the maximum depth of erosion as a function of basal shear stress (Schürch et al., 2011), and limits the rate of erosion to be less than the maximum erosion rate observed at the Illgraben by Berger et al. (2010, 2011). The entrainment model is a module implemented in the RAMMS debris-flow runout model which solves the 2D shallow water equations of motion for granular flows and includes the Voellmy friction relation (Christen et al., 2012). The intention of the model is to provide a tool to researchers and practitioners to estimate and investigate the influence of debris-flow erosion on the runout of debris flows, at least until new physically-based models are available. After calibration of the friction coefficients without considering entrainment, the model was systematically tested at two field sites where both the sequence of debris flows is known and where differential terrain elevation models have been used to identify the spatial pattern of erosion. Tests at the field site Spreitgraben (Canton Berne), where the channel slope on the fan is approximately 30%, indicate that the new model is better at predicting the flow pattern in comparison with model results without entrainment. Additionally, when sediment erosion is included in model, the shape of the debris-flow wave (flow depth as a function of time) has a generally steep debris-flow front, which is typical of field observations of debris flows. The model as also evaluated at the field site Meretschibach catchment (Canton

  5. Do the coarsest bed fractions and stream power record contemporary trends in steep headwater channels?

    NASA Astrophysics Data System (ADS)

    Galia, Tomáš; Škarpich, Václav

    2016-11-01

    Three stream channels that were devoid of evidence of past debris flows and one headwater channel that contained debris flow deposits in the flysch western Carpathians, Czech Republic were selected to test relationships between in-channel processes, bed sediments, and unit stream power calculated for bankfull and Q20 flows. Contemporary depositional or erosional trends in the examined headwaters were linked with bed sediments that were represented by the coarsest cobble and boulder fraction with a mean calculated from the five largest particles. The downstream trends of the unit stream power were derived for a bankfull discharge and a well-documented 20-year flood event. In addition, the flow competences during the discharges were calculated using indirect bedload transport measurements. Downstream fining of the cobble and boulder fraction was observed in all of the studied headwaters, and unique downstream variations of the unit stream power were calculated for the longitudinal profiles. The single-thread streams that were devoid of evidence of debris flow events exhibited direct relations between the coarsest sediment size and the unit stream power, especially as calculated for the 20-year flood event and for erosional/depositional trends of the channel. The downstream coarsening of the bed material that was accompanied by an increase in the unit stream power was usually observed in the case of deeply incised (> 0.5 m above the assumed bankfull depth) channel reaches. The calculated competence of the 20-year flow was up to twofold higher than that required to entrain the largest bed particle diameters in those channel reaches, and even the bankfull flow was potentially capable of transporting the coarsest bed particles in certain of the reaches. On the other hand, some depositional channel reaches evidently led to the disconnectivity of transport of the coarsest bed material even in the case of the 20-year flood event. The longitudinal profile of the channel that

  6. Laser and electron-beam powder-bed additive manufacturing of metallic implants: A review on processes, materials and designs.

    PubMed

    Sing, Swee Leong; An, Jia; Yeong, Wai Yee; Wiria, Florencia Edith

    2016-03-01

    Additive manufacturing (AM), also commonly known as 3D printing, allows the direct fabrication of functional parts with complex shapes from digital models. In this review, the current progress of two AM processes suitable for metallic orthopaedic implant applications, namely selective laser melting (SLM) and electron beam melting (EBM) are presented. Several critical design factors such as the need for data acquisition for patient-specific design, design dependent porosity for osteo-inductive implants, surface topology of the implants and design for reduction of stress-shielding in implants are discussed. Additive manufactured biomaterials such as 316L stainless steel, titanium-6aluminium-4vanadium (Ti6Al4V) and cobalt-chromium (CoCr) are highlighted. Limitations and future potential of such technologies are also explored.

  7. Laser and electron-beam powder-bed additive manufacturing of metallic implants: A review on processes, materials and designs.

    PubMed

    Sing, Swee Leong; An, Jia; Yeong, Wai Yee; Wiria, Florencia Edith

    2016-03-01

    Additive manufacturing (AM), also commonly known as 3D printing, allows the direct fabrication of functional parts with complex shapes from digital models. In this review, the current progress of two AM processes suitable for metallic orthopaedic implant applications, namely selective laser melting (SLM) and electron beam melting (EBM) are presented. Several critical design factors such as the need for data acquisition for patient-specific design, design dependent porosity for osteo-inductive implants, surface topology of the implants and design for reduction of stress-shielding in implants are discussed. Additive manufactured biomaterials such as 316L stainless steel, titanium-6aluminium-4vanadium (Ti6Al4V) and cobalt-chromium (CoCr) are highlighted. Limitations and future potential of such technologies are also explored. PMID:26488900

  8. Northern European Satellite Test Bed

    NASA Astrophysics Data System (ADS)

    Schuster-Bruce, Alan; Lawson, James; Quinlan, Michael; McGregor, Andrew

    Satellite Based Augmentation Systems are being developed in Europe (EGNOS), the USA (WAAS), and in Japan (MSAS). As part of their support to EGNOS, NATS and Racal have developed and deployed a prototype SBAS system called the Northern European Satellite Test Bed (NEST Bed). NEST Bed uses GPS L1/L2 reference stations at: Aberdeen, Rotterdam, Ankara, Cadiz, Keflavik, and Bronnoysund. Data is sent to the Master Control Centre at NATS Gatwick Services Management Centre for processing. The resulting 250 bits-per-second message is sent to Goonhilly for up-linking by BT to the Navigation Payload of either the Inmarsat AOR-E or F5 spare satellite. NEST Bed was deployed and commissioned during summer 1998, and flight tests were successfully demonstrated at the September 1998 Farnborough Air Show where approaches were flown to Boscombe Down on the DERA BAC1-11 aircraft. In October 1998, a NATS/FAA flight trial was held in Iceland involving NEST Bed and the FAA NSTB. NEST Bed is also being used for SARPS validation.

  9. Optimization of the pyrolysis process of empty fruit bunch (EFB) in a fixed-bed reactor through a central composite design (CCD)

    NASA Astrophysics Data System (ADS)

    Mohamed, Alina Rahayu; Hamz