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.

Innovative solar thermochemical water splitting.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hogan, Roy E. Jr.; Siegel, Nathan P.; Evans, Lindsey R.

2008-02-01

Sandia National Laboratories (SNL) is evaluating the potential of an innovative approach for splitting water into hydrogen and oxygen using two-step thermochemical cycles. Thermochemical cycles are heat engines that utilize high-temperature heat to produce chemical work. Like their mechanical work-producing counterparts, their efficiency depends on operating temperature and on the irreversibility of their internal processes. With this in mind, we have invented innovative design concepts for two-step solar-driven thermochemical heat engines based on iron oxide and iron oxide mixed with other metal oxides (ferrites). The design concepts utilize two sets of moving beds of ferrite reactant material in close proximitymore » and moving in opposite directions to overcome a major impediment to achieving high efficiency--thermal recuperation between solids in efficient counter-current arrangements. They also provide inherent separation of the product hydrogen and oxygen and are an excellent match with high-concentration solar flux. However, they also impose unique requirements on the ferrite reactants and materials of construction as well as an understanding of the chemical and cycle thermodynamics. In this report the Counter-Rotating-Ring Receiver/Reactor/Recuperator (CR5) solar thermochemical heat engine and its basic operating principals are described. Preliminary thermal efficiency estimates are presented and discussed. Our ferrite reactant material development activities, thermodynamic studies, test results, and prototype hardware development are also presented.« less

Biomass waste gasification - can be the two stage process suitable for tar reduction and power generation?

PubMed

Sulc, Jindřich; Stojdl, Jiří; Richter, Miroslav; Popelka, Jan; Svoboda, Karel; Smetana, Jiří; Vacek, Jiří; Skoblja, Siarhei; Buryan, Petr

2012-04-01

A pilot scale gasification unit with novel co-current, updraft arrangement in the first stage and counter-current downdraft in the second stage was developed and exploited for studying effects of two stage gasification in comparison with one stage gasification of biomass (wood pellets) on fuel gas composition and attainable gas purity. Significant producer gas parameters (gas composition, heating value, content of tar compounds, content of inorganic gas impurities) were compared for the two stage and the one stage method of the gasification arrangement with only the upward moving bed (co-current updraft). The main novel features of the gasifier conception include grate-less reactor, upward moving bed of biomass particles (e.g. pellets) by means of a screw elevator with changeable rotational speed and gradual expanding diameter of the cylindrical reactor in the part above the upper end of the screw. The gasifier concept and arrangement are considered convenient for thermal power range 100-350 kW(th). The second stage of the gasifier served mainly for tar compounds destruction/reforming by increased temperature (around 950°C) and for gasification reaction of the fuel gas with char. The second stage used additional combustion of the fuel gas by preheated secondary air for attaining higher temperature and faster gasification of the remaining char from the first stage. The measurements of gas composition and tar compound contents confirmed superiority of the two stage gasification system, drastic decrease of aromatic compounds with two and higher number of benzene rings by 1-2 orders. On the other hand the two stage gasification (with overall ER=0.71) led to substantial reduction of gas heating value (LHV=3.15 MJ/Nm(3)), elevation of gas volume and increase of nitrogen content in fuel gas. The increased temperature (>950°C) at the entrance to the char bed caused also substantial decrease of ammonia content in fuel gas. The char with higher content of ash leaving the second stage presented only few mass% of the inlet biomass stream. Copyright © 2011 Elsevier Ltd. All rights reserved.

A mixture theory approach to model co- and counter-current two-phase flow in porous media accounting for viscous coupling

NASA Astrophysics Data System (ADS)

Qiao, Y.; Andersen, P. Ø.; Evje, S.; Standnes, D. C.

2018-02-01

It is well known that relative permeabilities can depend on the flow configuration and they are commonly lower during counter-current flow as compared to co-current flow. Conventional models must deal with this by manually changing the relative permeability curves depending on the observed flow regime. In this paper we use a novel two-phase momentum-equation-approach based on general mixture theory to generate effective relative permeabilities where this dependence (and others) is automatically captured. In particular, this formulation includes two viscous coupling effects: (i) Viscous drag between the flowing phases and the stagnant porous rock; (ii) viscous drag caused by momentum transfer between the flowing phases. The resulting generalized model will predict that during co-current flow the faster moving fluid accelerates the slow fluid, but is itself decelerated, while for counter-current flow they are both decelerated. The implications of these mechanisms are demonstrated by investigating recovery of oil from a matrix block surrounded by water due to a combination of gravity drainage and spontaneous imbibition, a situation highly relevant for naturally fractured reservoirs. We implement relative permeability data obtained experimentally through co-current flooding experiments and then explore the model behavior for different flow cases ranging from counter-current dominated to co-current dominated. In particular, it is demonstrated how the proposed model seems to offer some possible interesting improvements over conventional modeling by providing generalized mobility functions that automatically are able to capture more correctly different flow regimes for one and the same parameter set.

Counter-current motion in counter-current chromatography.

PubMed

Ito, Yoichiro

2014-12-12

After the CCC2012 meeting, I have received an e-mail regarding the terminology of "Countercurrent Chromatography". It stated that the term "Countercurrent" is a misnomer, because its stationary phase is motionless in the column and that the method should be renamed as liquid-liquid separations or centrifugal separations. However, it was found that these names are already used for various other techniques as found via Google search. The term "Countercurrent Chromatography" was originally made after two preparative methods of Countercurrent distribution and liquid Chromatography, both having no countercurrent motion in the column. However, it is surprising to find that this F1 hybrid method "Countercurrent Chromatography" can clearly exhibit countercurrent motion within the separation column in both hydrodynamic and hydrostatic equilibrium systems. This justifies that "Countercurrent Chromatography" is a proper term for this chromatographic method. Published by Elsevier B.V.

Coastal counter-currents setup patterns in the Gulf of Cadiz

NASA Astrophysics Data System (ADS)

Relvas, P.; Juniór, L.; Garel, E.; Drago, T.

2017-12-01

Alongshore coastal counter-currents (CCC) are frequent features of Eastern Boundary Upwelling Systems, where they temporally alternate with upwelling driven jets of opposite direction. Along the northern margin of the Gulf of Cadiz inner shelf, these CCCs are oriented poleward (eastward) and responsible for sharp temperature increases during the upwelling season, along with potential decline in water quality at the coast. This research is based on a multi-year ADCP velocity time-series (2008-2017), recorded at a single location (23 m water depth) over 13 deployments up to 3 months-long. The analysis focuses on the water column alongshore velocities during current inversions (i.e., the transition from equatorward upwelling jets to poleward CCCs). A set of parameters were derived from the flow structure to identify distinct types of inversions and to hypothesize about their driving mechanisms. Results show that 77% of the inversions start near the bed, propagating then to the upper layers. The bottom layer also changes direction before the surface layer for most events (71%). The vertical shear in this case is one order of magnitude greater than in the (less frequent) opposite situation. No seasonal variability is observed in the CCC occurrences. However, the parameters analysed in this study suggest different types of inversion between winter and summer. In winter, inversions are well defined (low variability), with similar patterns near the surface and bed layers as a result of a strong barotropic component. In summer the inversion patterns are more variable. In particular, the upper and bed layers are often importantly decoupled during inversions, indicating the strengthening of baroclinicity. A categorization of inversions events is proposed based on cross-correlation and multi-variable analyses of the developed parameters. Various types of inversion are obtained, suggesting that CCCs are driven by different forcings that may act separately or jointly.

Marginal bed load transport in a gravel bed stream, Sagehen Creek, California

USGS Publications Warehouse

Andrews, E.D.

1994-01-01

Marginal bed load transport describes the condition when relatively few bed particles are moving at any time. Bed particles resting in the shallowest bed pockets will move when the dimensionless shear stress т* exceeds a value of about 0.020. As т* increases, the number of bed particles moving increases. Significant motion of bed particles, i.e., when a substantial fraction of the bed particles are moving, occurs when т* exceeds a value of about 0.060. Thus marginal bed load transport occurs over the domain 0.020 < т* < 0.060. Marginal bed load transport rates and associated hydraulic characteristics of Sagehen Creek, a small mountain gravel bed stream, were measured on 55 days at discharges ranging from slightly less than one half of the bank-full discharge to more than 4 times the bank-full discharge. Dimensionless shear stress varied from 0.032 to 0.042, and bed particles as large as the 80th percentile of the bed surface were transported. The relation between reference dimensionless shear stress and relative particle protrusion for Sagehen Creek was determined by varying т*ri to obtain the best fit of the Parker bed load function to the measured transport rates. During the period of record (water years 1954–1991), the mean annual quantity of bed load transported past the Sagehen Creek gage was 24.7 tons. Forty-seven percent of all bed load transported during the 38 years of record occurred in just 6 years. During 10 of the 38 years of record, essentially no bed load was transported. The median diameter of bed load was 26 mm, compared to 58 mm in the surface bed material.

High-throughput countercurrent microextraction in passive mode.

PubMed

Xie, Tingliang; Xu, Cong

2018-05-15

Although microextraction is much more efficient than conventional macroextraction, its practical application has been limited by low throughputs and difficulties in constructing robust countercurrent microextraction (CCME) systems. In this work, a robust CCME process was established based on a novel passive microextractor with four units without any moving parts. The passive microextractor has internal recirculation and can efficiently mix two immiscible liquids. The hydraulic characteristics as well as the extraction and back-extraction performance of the passive CCME were investigated experimentally. The recovery efficiencies of the passive CCME were 1.43-1.68 times larger than the best values achieved using cocurrent extraction. Furthermore, the total throughput of the passive CCME developed in this work was about one to three orders of magnitude higher than that of other passive CCME systems reported in the literature. Therefore, a robust CCME process with high throughputs has been successfully constructed, which may promote the application of passive CCME in a wide variety of fields.

Simulated moving bed system for CO.sub.2 separation, and method of same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Jeannine Elizabeth; Copeland, Robert James; Lind, Jeff

A system and method for separating and/or purification of CO.sub.2 gas from a CO.sub.2 feed stream is described. The system and method include a plurality of fixed sorbent beds, adsorption zones and desorption zones, where the sorbent beds are connected via valve and lines to create a simulated moving bed system, where the sorbent beds move from one adsorption position to another adsorption position, and then into one regeneration position to another regeneration position, and optionally back to an adsorption position. The system and method operate by concentration swing adsorption/desorption and by adsorptive/desorptive displacement.

Apparatus and method for determining solids circulation rate

DOEpatents

Ludlow, J Christopher [Morgantown, WV; Spenik, James L [Morgantown, WV

2012-02-14

The invention relates to a method of determining bed velocity and solids circulation rate in a standpipe experiencing a moving packed bed flow, such as the in the standpipe section of a circulating bed fluidized reactor The method utilizes in-situ measurement of differential pressure over known axial lengths of the standpipe in conjunction with in-situ gas velocity measurement for a novel application of Ergun equations allowing determination of standpipe void fraction and moving packed bed velocity. The method takes advantage of the moving packed bed property of constant void fraction in order to integrate measured parameters into simultaneous solution of Ergun-based equations and conservation of mass equations across multiple sections of the standpipe.

Feasibility Study of the Geotextile Waste Filtration Unit.

DTIC Science & Technology

2000-02-10

Treatment Module 3-32 Figure 3-20. THE SCHEMATIC OF THE MOVING BED BIOFILM REACTOR ( MBBR ) 3൪ Figure 4-1. The Original Distributed Concept for WFUs...Moving Bed Biofilm Reactor ( MBBR ) process appears to be one of the most feasible processes available to meet Force Provider liquid waste stream...Moving Bed Biofilm Reactor ( MBBR ) process was then examined.31 In this system, both activated sludge and fixed-film processes occur in a bioreactor

Rotary moving bed for CO.sub.2 separation and use of same

DOEpatents

Elliott, Jeannine Elizabeth; Copeland, Robert James; McCall, Patrick P.

2017-01-10

A rotary moving bed and process for separating a carbon dioxide from a gas stream is disclosed. The rotary moving bed can have a rotational assembly rotating on a vertical axis, and a plurality of sorbent cells positioned horizontally to the axis of rotation that fills a vertical space in the moving bed, where the sorbent cells adsorb the carbon dioxide by concentration swing adsorption and adsorptive displacement. The sorbent can be regenerated and the carbon dioxide recaptured by desorbing the carbon dioxide from the sorbent using concentration swing adsorption and desorptive displacement with steam. The gas flows in the system flow in a direction horizontal to the axis of rotation and in a direction opposite the rotational movement of the sorbent cells.

Centrifugal precipitation chromatography

PubMed Central

Ito, Yoichiro; Lin, Qi

2009-01-01

Centrifugal precipitation chromatography separates analytes according their solubility in ammonium sulfate (AS) solution and other precipitants. The separation column is made from a pair of long spiral channels partitioned with a semipermeable membrane. In a typical separation, concentrated ammonium sulfate is eluted through one channel while water is eluted through the other channel in the opposite direction. The countercurrent process forms an exponential AS concentration gradient through the water channel. Consequently, protein samples injected into the water channel is subjected to a steadily increasing AS concentration and at the critical AS concentration they are precipitated and deposited in the channel bed by the centrifugal force. Then the chromatographic separation is started by gradually reducing the AS concentration in the AS channel which lowers the AS gradient concentration in the water channel. This results in dissolution of deposited proteins which are again precipitated at an advanced critical point as they move through the channel. Consequently, proteins repeat precipitation and dissolution through a long channel and finally eluted out from the column in the order of their solubility in the AS solution. The present method has been successfully applied to a number of analytes including human serum proteins, recombinant ketosteroid isomerase, carotenoid cleavage enzymes, plasmid DNA, polysaccharide, polymerized pigments, PEG-protein conjugates, etc. The method is capable to single out the target species of proteins by affinity ligand or immunoaffinity separation. PMID:19541553

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.

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

PubMed

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

2009-06-15

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

Wavelike movement of bedload sediment, East Fork River, Wyoming

USGS Publications Warehouse

Meade, R.H.

1985-01-01

Bedload is moved down the East Fork River in distinct wavelike pulses that have the form of composite dune fields The moving material consists mostly of coarse sand and fine gravel The wavelengths of the pulses are about 500-600 m, a distance that is predetermined by the pattern of stoage of bed sediment in the river during low water As the river discharge increases, the bed sediment is scoured from the storage areas, and it is moved onto and across the interventing riffles As the river discharge decreases, the bed sediment is scoured off the riffles and moved into the next storage area downstream Each successive pulse of water discharge sets into motion a wave of bedload that continues to move unitil it reaches the next storage area ?? 1985 Springer-Verlag New York Inc.

Early processing variations in selective attention to the color and direction of moving stimuli during 30 days head-down bed rest

NASA Astrophysics Data System (ADS)

Wang, Lin-Jie; He, Si-Yang; Niu, Dong-Bin; Guo, Jian-Ping; Xu, Yun-Long; Wang, De-Sheng; Cao, Yi; Zhao, Qi; Tan, Cheng; Li, Zhi-Li; Tang, Guo-Hua; Li, Yin-Hui; Bai, Yan-Qiang

2013-11-01

Dynamic variations in early selective attention to the color and direction of moving stimuli were explored during a 30 days period of head-down bed rest. Event-related potentials (ERPs) were recorded at F5, F6, P5, P6 scalp locations in seven male subjects who attended to pairs of bicolored light emitting diodes that flashed sequentially to produce a perception of movement. Subjects were required to attend selectively to a critical feature of the moving target, e.g., color or direction. The tasks included: a no response task, a color selective response task, a moving direction selective response task, and a combined color-direction selective response task. Subjects were asked to perform these four tasks on: the 3rd day before bed rest; the 3rd, 15th and 30th day during the bed rest; and the 5th day after bed rest. Subjects responded quickly to the color than moving direction and combined color-direction response. And they had a longer reaction time during bed rest on the 15th and 30th day during bed rest after a relatively quicker response on the 3rd day. Using brain event-related potentials technique, we found that in the color selective response task, the mean amplitudes of P1 and N1 for target ERPs decreased in the 3rd day during bed rest and 5th day after bed rest in comparison with pre-bed rest, 15th day and 30th day during bed rest. In the combined color-direction selective response task, the P1 latencies for target ERPs on the 3rd and 30th day during bed rest were longer than on the 15th day during bed rest. As 3rd day during bed rest was in the acute adaptation period and 30th day during bed rest was in the relatively adaptation stage of head-down bed rest, the results help to clarify the effects of bed rest on different task loads and patterns of attention. It was suggested that subjects expended more time to give correct decision in the head-down tilt bed rest state. A difficulty in the recruitment of brain resources was found in feature selection task, but no variations were detected in the no response and direction selective response tasks. It is suggested that the negative shift in color selective response task on the 3rd day of bed rest are a result of fluid redistribution. And feature selection was more affected than motion selection in the head down bed rest. The variations in cognitive processing speed observed for the combined color-direction selective response task are suggested to reflect the interaction between top-down mechanisms and hierarchical physiological characteristics during 30 days head-down bed rest.

Isolation of dimeric, trimeric, tetrameric and pentameric procyanidins from unroasted cocoa beans (Theobroma cacao L.) using countercurrent chromatography.

PubMed

Esatbeyoglu, Tuba; Wray, Victor; Winterhalter, Peter

2015-07-15

The main procyanidins, including dimeric B2 and B5, trimeric C1, tetrameric and pentameric procyanidins, were isolated from unroasted cocoa beans (Theobroma cacao L.) using various techniques of countercurrent chromatography, such as high-speed countercurrent chromatography (HSCCC), low-speed rotary countercurrent chromatography (LSRCCC) and spiral-coil LSRCCC. Furthermore, dimeric procyanidins B1 and B7, which are not present naturally in the analysed cocoa beans, were obtained after semisynthesis of cocoa bean polymers with (+)-catechin as nucleophile and separated by countercurrent chromatography. In this way, the isolation of dimeric procyanidin B1 in considerable amounts (500mg, purity>97%) was possible in a single run. This is the first report concerning the isolation and semisynthesis of dimeric to pentameric procyanidins from T. cacao by countercurrent chromatography. Additionally, the chemical structures of tetrameric (cinnamtannin A2) and pentameric procyanidins (cinnamtannin A3) were elucidated on the basis of (1)H NMR spectroscopy. Interflavanoid linkage was determined by NOE-correlations, for the first time. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Advances in studies on multi-stage countercurrent extraction technology in traditional Chinese medicine].

PubMed

Xie, Zhi-Peng; Liu, Xue-Song; Chen, Yong; Cai, Ming; Qu, Hai-Bin; Cheng, Yi-Yu

2007-05-01

Multi-stage countercurrent extraction technology, integrating solvent extraction, repercolation with dynamic and countercurrent extraction, is a novel extraction technology for the traditional Chinese medicine. This solvent-saving, energy-saving and high-extraction-efficiency technology can at the most drive active compounds to diffuse from the herbal materials into the solvent stage by stage by creating concentration differences between the herbal materials and the solvents. This paper reviewed the basic principle, the influence factors and the research progress and trends of the equipments and the application of the multi-stage countercurrent extraction.

The application of moving bed biofilm reactor to denitrification process after trickling filters.

PubMed

Kopec, Lukasz; Drewnowski, Jakub; Kopec, Adam

2016-12-01

The paper presents research of a prototype moving bed biofilm reactor (MBBR). The device was used for the post-denitrification process and was installed at the end of a technological system consisting of a septic tank and two trickling filters. The concentrations of suspended biomass and biomass attached on the EvU Perl moving bed surface were determined. The impact of the external organic carbon concentration on the denitrification rate and efficiency of total nitrogen removal was also examined. The study showed that the greater part of the biomass was in the suspended form and only 6% of the total biomass was attached to the surface of the moving bed. Abrasion forces between carriers of the moving bed caused the fast stripping of attached microorganisms and formation of flocs. Thanks to immobilization of a small amount of biomass, the MBBR was less prone to leaching of the biomass and the occurrence of scum and swelling sludge. It was revealed that the maximum rate of denitrification was an average of 0.73 gN-NO 3 /gDM·d (DM: dry matter), and was achieved when the reactor was maintained in external organic carbon concentration exceeding 300 mgO 2 /dm 3 chemical oxygen demand. The reactor proved to be an effective device enabling the increase of total nitrogen removal from 53.5% to 86.0%.

Preparative isolation and purification of hainanmurpanin, meranzin, and phebalosin from leaves of Murraya exotica L. using supercritical fluid extraction combined with consecutive high-speed countercurrent chromatography.

PubMed

Yan, Rongwei; Shen, Jie; Liu, Xiaojing; Zou, Yong; Xu, Xinjun

2018-05-01

The objective of this study was to develop a consecutive preparation method for the isolation and purification of hainanmurpanin, meranzin, and phebalosin from leaves of Murraya exotica L. The process involved supercritical fluid extraction with CO 2 , solvent extraction, and two-step high-speed countercurrent chromatography. Pressure, temperature, and the volume of entrainer were optimized as 27 MPa, 52°C, and 60 mL by response surface methodology in supercritical fluid extraction with CO 2 , and the yield of the crude extracts was 7.91 g from 100 g of leaves. Subsequently, 80% methanol/water was used to extract and condense the three compounds from the crude extracts, and 4.23 g of methanol/water extracts was obtained. Then, a two-step high-speed countercurrent chromatography procedure was developed for the isolation of the three target compounds from methanol/water extracts, including conventional high-speed countercurrent chromatography for further enrichment and consecutive high-speed countercurrent chromatography for purification. The yield of concentrates from high-speed countercurrent chromatography was 2.50 g from 4.23 g of methanol/water extracts. Finally, the consecutive high-speed countercurrent chromatography produced 103.2 mg of hainanmurpanin, 244.7 mg of meranzin, and 255.4 mg of phebalosin with purities up to 97.66, 99.36, and 98.64%, respectively, from 900 mg of high-speed countercurrent chromatography concentrates in one run of three consecutive sample loadings without exchanging a solvent system. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Simulated Moving Bed Chromatography: Separation and Recovery of Sugars and Ionic Liquid from Biomass Hydrolysates

PubMed Central

Caes, Benjamin R.; Van Oosbree, Thomas R.; Lu, Fachuang; Ralph, John; Maravelias, Christos T.

2015-01-01

Simulated moving bed chromatography, a continuous separation method, enables the nearly quantitative recovery of sugar products and ionic liquid solvent from chemical hydrolysates of biomass. The ensuing sugars support microbial growth, and the residual lignin from the process is intact. PMID:23939991

Computational Study of Colloidal Droplet Interactions with Three Dimensional Structures

DTIC Science & Technology

2015-05-18

on the meshless SPH method for droplet impact on and sorption into a powder bed considering free surface flow above the powder bed surface ...considering free surface flow above the powder bed surface , infiltration of the liquid in the porous matrix, and the interfacial forces on the free moving...infiltration of the liquid in the porous matrix, and the interfacial forces on the free moving surface . The model has been used to study the effect of impact

The 9th International Countercurrent Chromatography Conference held at Dominican University, Chicago, USA, August 1-3, 2016.

PubMed

Friesen, J Brent; McAlpine, James B; Chen, Shao-Nong; Pauli, Guido F

2017-10-20

The 9th International Countercurrent Chromatography Conference (CCC 2016) was held at Dominican University near Chicago, IL (USA), from August 1st-3rd, 2016. The biennial CCC 20XX conferences provide an opportunity for countercurrent chromatography and centrifugal partition chromatography (CCC/CPC) manufactures, marketers, theorists, and research scientists to gather together socially, learn from each other, and advance countercurrent separation technology. A synopsis of the conference proceedings as well as a series of short reviews of the special edition articles is included in this document. Many productive discussions and collegial conversation at CCC 2016 attested to the liveliness, connectivity, and productivity of the global countercurrent research community and bodes well for the success of the 10th conference at the University of Braunschweig, Germany on August 1-3, 2018. Copyright © 2017 Elsevier B.V. All rights reserved.

Spiral counter-current chromatography: Design, development, application, and challenges.

PubMed

Huang, Xin-Yi; Sun, Xiao-Ming; Pei, Dong; Di, Duo-Long

2017-01-01

Depending on the rapid growth in the radial gradient of the centrifugal force, spiral counter-current chromatography can greatly improve the retention of stationary phase, especially for the aqueous two-phase systems with ultra-polar and high viscosity that are not well retained in the conventional multilayer coils counter-current chromatography. As a result, it is an attractive and alternative technology that is suited for separation of hydrophilic compounds and has led to many exciting progress in recent years. This review presents the recent advances and applications of spiral counter-current chromatography, including its major benefits and limitations, some novel methods to improve the separation efficiency and its applications in separation of real samples. In addition, the remaining challenges and future perspectives on development of spiral counter-current chromatography also are proposed in this article. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evaluation of ADCP apparent bed load velocity in a large sand-bed river: Moving versus stationary boat conditions

USGS Publications Warehouse

Jamieson, E.C.; Rennie, C.D.; Jacobson, R.B.; Townsend, R.D.

2011-01-01

Detailed mapping of bathymetry and apparent bed load velocity using a boat-mounted acoustic Doppler current profiler (ADCP) was carried out along a 388-m section of the lower Missouri River near Columbia, Missouri. Sampling transects (moving boat) were completed at 5- and 20-m spacing along the study section. Stationary (fixed-boat) measurements were made by maintaining constant boat position over a target point where the position of the boat did not deviate more than 3 m in any direction. For each transect and stationary measurement, apparent bed load velocity (vb) was estimated using ADCP bottom tracking data and high precision real-time kinematic (RTK) global positioning system (GPS). The principal objectives of this research are to (1) determine whether boat motion introduces a bias in apparent bed load velocity measurements; and (2) evaluate the reliability of ADCP bed velocity measurements for a range of sediment transport environments. Results indicate that both high transport (vb>0.6 m/s) and moving-boat conditions (for both high and low transport environments) increase the relative variability in estimates of mean bed velocity. Despite this, the spatially dense single-transect measurements were capable of producing detailed bed velocity maps that correspond closely with the expected pattern of sediment transport over large dunes. ?? 2011 American Society of Civil Engineers.

An audit of the use of isolation facilities in a UK National Health Service trust.

PubMed

Damji, S; Barlow, G D; Patterson, L; Nathwani, D

2005-07-01

To aid the ongoing battle against hospital-acquired infection in the UK, all acute National Health Service (NHS) trusts should have audit data about how dedicated isolation beds within the trust are being used. In a previously published audit, we demonstrated that one-third of patients admitted to a dedicated isolation room in Tayside were not thought to be an infection risk by experienced healthcare staff. Since this audit, Tayside's isolation facilities have moved from a small peripheral 'fever' hospital to a large central teaching hospital site. At the time of this move, and using the above audit data, we designed and implemented a guideline for general practitioners and hospital doctors regarding the admission of patients to an isolation bed. The aim of this study was to compare the use of isolation beds before and after the move to the new facilities, which we anticipated would increase the demand for isolation. The results show that by all three criteria used, the utilization of isolation beds has deteriorated following the move, mainly due to the increased admission of general medical 'boarders' and low-risk infection patients. At a time when hospital-acquired infections are increasing, NHS trusts should ensure that dedicated isolation beds are used appropriately.

Solar tower power plant using a particle-heated steam generator: Modeling and parametric study

NASA Astrophysics Data System (ADS)

Krüger, Michael; Bartsch, Philipp; Pointner, Harald; Zunft, Stefan

2016-05-01

Within the framework of the project HiTExStor II, a system model for the entire power plant consisting of volumetric air receiver, air-sand heat exchanger, sand storage system, steam generator and water-steam cycle was implemented in software "Ebsilon Professional". As a steam generator, the two technologies fluidized bed cooler and moving bed heat exchangers were considered. Physical models for the non-conventional power plant components as air- sand heat exchanger, fluidized bed coolers and moving bed heat exchanger had to be created and implemented in the simulation environment. Using the simulation model for the power plant, the individual components and subassemblies have been designed and the operating parameters were optimized in extensive parametric studies in terms of the essential degrees of freedom. The annual net electricity output for different systems was determined in annual performance calculations at a selected location (Huelva, Spain) using the optimized values for the studied parameters. The solution with moderate regenerative feed water heating has been found the most advantageous. Furthermore, the system with moving bed heat exchanger prevails over the system with fluidized bed cooler due to a 6 % higher net electricity yield.

Bed Bugs and Schools

EPA Pesticide Factsheets

Bed bugs have long been a pest – feeding on blood, causing itchy bites and generally irritating their human hosts. They are successful hitchhikers, and can move from an infested site to furniture, bedding, baggage, boxes, and clothing.

Method and apparatus for filtering gas with a moving granular filter bed

DOEpatents

Brown, Robert C.; Wistrom, Corey; Smeenk, Jerod L.

2007-12-18

A method and apparatus for filtering gas (58) with a moving granular filter bed (48) involves moving a mass of particulate filter material (48) downwardly through a filter compartment (35); tangentially introducing gas into the compartment (54) to move in a cyclonic path downwardly around the moving filter material (48); diverting the cyclonic path (58) to a vertical path (62) to cause the gas to directly interface with the particulate filter material (48); thence causing the gas to move upwardly through the filter material (48) through a screened partition (24, 32) into a static upper compartment (22) of a filter compartment for exodus (56) of the gas which has passed through the particulate filter material (48).

Counter-current acid leaching process for copper azole treated wood waste.

PubMed

Janin, Amélie; Riche, Pauline; Blais, Jean-François; Mercier, Guy; Cooper, Paul; Morris, Paul

2012-09-01

This study explores the performance of a counter-current leaching process (CCLP) for copper extraction from copper azole treated wood waste for recycling of wood and copper. The leaching process uses three acid leaching steps with 0.1 M H2SO4 at 75degrees C and 15% slurry density followed by three rinses with water. Copper is recovered from the leachate using electrodeposition at 5 amperes (A) for 75 min. Ten counter-current remediation cycles were completed achieving > or = 94% copper extraction from the wood during the 10 cycles; 80-90% of the copper was recovered from the extract solution by electrodeposition. The counter-current leaching process reduced acid consumption by 86% and effluent discharge volume was 12 times lower compared with the same process without use of counter-current leaching. However, the reuse of leachates from one leaching step to another released dissolved organic carbon and caused its build-up in the early cycles.

AORN ergonomic tool 1: Lateral transfer of a patient from a stretcher to an OR bed.

PubMed

Waters, Thomas; Baptiste, Andrea; Short, Manon; Plante-Mallon, Lori; Nelson, Audrey

2011-03-01

Moving patients can result in injuries to patients and staff members. Lateral patient transfers from a stretcher to an OR bed pose a high risk for musculoskeletal disorders, including lower back, shoulder, and neck injuries for perioperative personnel. AORN Ergonomic Tool 1: Lateral Transfer of a Patient from a Stretcher to an OR Bed helps perioperative staff members determine best practices for safe lateral patient transfers. Safe moving of the patient is determined by the starting and ending position required and the patient's weight. Current ergonomic safety concepts and scientific evidence regarding weight limits help to determine how many caregivers are needed to safely move patients and whether mechanical assistance is needed during lateral transfers. Published by Elsevier Inc.

An Intelligent Robotic Hospital Bed for Safe Transportation of Critical Neurosurgery Patients Along Crowded Hospital Corridors.

PubMed

Wang, Chao; Savkin, Andrey V; Clout, Ray; Nguyen, Hung T

2015-09-01

We present a novel design of an intelligent robotic hospital bed, named Flexbed, with autonomous navigation ability. The robotic bed is developed for fast and safe transportation of critical neurosurgery patients without changing beds. Flexbed is more efficient and safe during the transportation process comparing to the conventional hospital beds. Flexbed is able to avoid en-route obstacles with an efficient easy-to-implement collision avoidance strategy when an obstacle is nearby and to move towards its destination at maximum speed when there is no threat of collision. We present extensive simulation results of navigation of Flexbed in the crowded hospital corridor environments with moving obstacles. Moreover, results of experiments with Flexbed in the real world scenarios are also presented and discussed.

Separation of particulate from flue gas of fossil fuel combustion and gasification

DOEpatents

Yang, W.C.; Newby, R.A.; Lippert, T.E.

1997-08-05

The gas from combustion or gasification of fossil fuel contains fly ash and other particulates. The fly ash is separated from the gas in a plurality of standleg moving granular-bed filter modules. Each module includes a dipleg through which the bed media flows into the standleg. The bed media forms a first filter bed having an upper mass having a first frusto-conical surface in a frusto-conical member at the entrance to the standleg and a lower mass having a second frusto-conical surface of substantially greater area than the first surface after it passes through the standleg. A second filter media bed may be formed above the first filter media bed. The gas is fed tangentially into the module above the first surface. The fly ash is captured on the first frusto-conical surface and within the bed mass. The processed gas flows out through the second frusto-conical surface and then through the second filter bed, if present. The bed media is cleaned of the captured fly ash and recirculated to the moving granular bed filter. Alternatively, the bed media may be composed of the ash from the combustion which is pelletized to form agglomerates. The ash flows through the bed only once; it is not recycled. 11 figs.

Separation of particulate from flue gas of fossil fuel combustion and gasification

DOEpatents

Yang, Wen-Ching; Newby, Richard A.; Lippert, Thomas E.

1997-01-01

The gas from combustion or gasification of fossil fuel contains flyash and other particulate. The flyash is separated from the gas in a plurality of standleg moving granular-bed filter modules. Each module includes a dipleg through which the bed media flows into the standleg. The bed media forms a first filter bed having an upper mass having a first frusto-conical surface in a frusto-conical member at the entrance to the standleg and a lower mass having a second frusto-conical surface of substantially greater area than the first surface after it passes through the standleg. A second filter media bed may be formed above the first filter media bed. The gas is fed tangentially into the module above the first surface. The flyash is captured on the first frusto-conical surface and within the bed mass. The processed gas flows out through the second frusto-conical surface and then through the second filter bed, if present. The bed media is cleaned of the captured flyash and recirculated to the moving granular bed filter. Alternatively, the bed media may be composed of the ash from the combustion which is pelletized to form agglomerates. The ash flows through the bed only once; it is not recycled.

Numerical investigation of flow and heat transfer in a novel configuration multi-tubular fixed bed reactor for propylene to acrolein process

NASA Astrophysics Data System (ADS)

Jiang, Bin; Hao, Li; Zhang, Luhong; Sun, Yongli; Xiao, Xiaoming

2015-01-01

In the present contribution, a numerical study of fluid flow and heat transfer performance in a pilot-scale multi-tubular fixed bed reactor for propylene to acrolein oxidation reaction is presented using computational fluid dynamics (CFD) method. Firstly, a two-dimensional CFD model is developed to simulate flow behaviors, catalytic oxidation reaction, heat and mass transfer adopting porous medium model on tube side to achieve the temperature distribution and investigate the effect of operation parameters on hot spot temperature. Secondly, based on the conclusions of tube-side, a novel configuration multi-tubular fixed-bed reactor comprising 790 tubes design with disk-and-doughnut baffles is proposed by comparing with segmental baffles reactor and their performance of fluid flow and heat transfer is analyzed to ensure the uniformity condition using molten salt as heat carrier medium on shell-side by three-dimensional CFD method. The results reveal that comprehensive performance of the reactor with disk-and-doughnut baffles is better than that of with segmental baffles. Finally, the effects of operating conditions to control the hot spots are investigated. The results show that the flow velocity range about 0.65 m/s is applicable and the co-current cooling system flow direction is better than counter-current flow to control the hottest temperature.

Evaluation of three types of structured floating plastic media in moving bed biofilters for total ammonia nitrogen removal in a low salinity hatchery recirculating aquaculture system

USDA-ARS?s Scientific Manuscript database

Three different commercially available structural plastic media were evaluated in triplicate in moving bed toriod filters under low salinity (11-12 ppt) warm water culture conditions and two different feed loading rates. The culture system consisted of nine separate modules that include a double dra...

Application of a Line Laser Scanner for Bed Form Tracking in a Laboratory Flume

NASA Astrophysics Data System (ADS)

de Ruijsscher, T. V.; Hoitink, A. J. F.; Dinnissen, S.; Vermeulen, B.; Hazenberg, P.

2018-03-01

A new measurement method for continuous detection of bed forms in movable bed laboratory experiments is presented and tested. The device consists of a line laser coupled to a 3-D camera, which makes use of triangulation. This allows to measure bed forms during morphodynamic experiments, without removing the water from the flume. A correction is applied for the effect of laser refraction at the air-water interface. We conclude that the absolute measurement error increases with increasing flow velocity, its standard deviation increases with water depth and flow velocity, and the percentage of missing values increases with water depth. Although 71% of the data is lost in a pilot moving bed experiment with sand, still high agreement between flowing water and dry bed measurements is found when a robust LOcally weighted regrESSion (LOESS) procedure is applied. This is promising for bed form tracking applications in laboratory experiments, especially when lightweight sediments like polystyrene are used, which require smaller flow velocities to achieve dynamic similarity to the prototype. This is confirmed in a moving bed experiment with polystyrene.

Combinative application of pH-zone-refining and conventional high-speed counter-current chromatography for preparative separation of caged polyprenylated xanthones from gamboge.

PubMed

Xu, Min; Fu, Wenwei; Zhang, Baojun; Tan, Hongsheng; Xiu, Yanfeng; Xu, Hongxi

2016-02-01

An efficient method for the preparative separation of four structurally similar caged xanthones from the crude extracts of gamboge was established, which involves the combination of pH-zone-refining counter-current chromatography and conventional high-speed counter-current chromatography for the first time. pH-zone-refining counter-current chromatography was performed with the solvent system composed of n-hexane/ethyl acetate/methanol/water (7:3:8:2, v/v/v/v), where 0.1% trifluoroacetic acid was added to the upper organic stationary phase as a retainer and 0.03% triethylamine was added to the aqueous mobile phase as an eluter. From 3.157 g of the crude extract, 1.134 g of gambogic acid, 180.5 mg of gambogenic acid and 572.9 mg of a mixture of two other caged polyprenylated xanthones were obtained. The mixture was further separated by conventional high-speed counter-current chromatography with a solvent system composed of n-hexane/ethyl acetate/methanol/water (5:5:10:5, v/v/v/v) and n-hexane/methyl tert-butyl ether/acetonitrile/water (8:2:6:4,v/v/v/v), yielding 11.6 mg of isogambogenic acid and 10.4 mg of β-morellic acid from 218.0 mg of the mixture, respectively. The purities of all four of the compounds were over 95%, as determined by high-performance liquid chromatography, and the chemical structures of the four compounds were confirmed by electrospray ionization mass spectrometry and NMR spectroscopy. The combinative application of pH-zone-refining counter-current chromatography and conventional high-speed counter-current chromatography shows great advantages in isolating and enriching the caged polyprenylated xanthones. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation and purification of hydrolyzable tannin from Geranium wilfordii Maxim by reversed-phase and normal-phase high-speed counter-current chromatography.

PubMed

Liu, Dan; Su, Zhiguo; Wang, Changhai; Gu, Ming; Xing, Siliang

2010-08-01

Three hydrolyzable tannins, geraniin, corilagin and gallic acid, main active components of Geranium wilfordii Maxim, have been separated and purified in one-step by both reversed-phase and normal-phase high-speed counter-current chromatography. Gallic acid, corilagin and geraniin were purified from 70% aqueous acetone extract of G. wilfordii Maxim with solvent system n-hexane-ethyl acetate-methanol-acetic acid-water (1:10:0.2:0.2:20) by reversed-phase high-speed counter-current chromatography at purities of 94.2, 91.0 and 91.3%, at yields of 89.3, 82.9 and 91.7%, respectively. Gallic acid, corilagin and geraniin were purified with solvent system n-hexane-ethyl acetate-methanol-acetic acid-water (0.2:10:2:1:5) by normal-phase high-speed counter-current chromatography at purities of 85.9, 92.2 and 87.6%, at yields of 87.4, 94.6 and 94.3%, respectively. It was successful for both reversed-phase and normal-phase high-speed counter-current chromatography to separate high-polarity of low-molecular-weight substances.

Method and system for continuous atomic layer deposition

DOEpatents

Elam, Jeffrey W.; Yanguas-Gil, Angel; Libera, Joseph A.

2017-03-21

A system and method for continuous atomic layer deposition. The system and method includes a housing, a moving bed which passes through the housing, a plurality of precursor gases and associated input ports and the amount of precursor gases, position of the input ports, and relative velocity of the moving bed and carrier gases enabling exhaustion of the precursor gases at available reaction sites.

Scaling of Counter-Current Imbibition Process in Low-Permeability Porous Media, TR-121

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kvoscek, A.R.; Zhou, D.; Jia, L.

2001-01-17

This project presents the recent work on imaging imbibition in low permeability porous media (diatomite) with X-ray completed tomography. The viscosity ratio between nonwetting and wetting fluids is varied over several orders of magnitude yielding different levels of imbibition performance. Also performed is mathematical analysis of counter-current imbibition processes and development of a modified scaling group incorporating the mobility ratio. This modified group is physically based and appears to improve scaling accuracy of countercurrent imbibition significantly.

Diffusive shunting of gases and other molecules in the renal vasculature: physiological and evolutionary significance.

PubMed

Ngo, Jennifer P; Ow, Connie P C; Gardiner, Bruce S; Kar, Saptarshi; Pearson, James T; Smith, David W; Evans, Roger G

2016-11-01

Countercurrent systems have evolved in a variety of biological systems that allow transfer of heat, gases, and solutes. For example, in the renal medulla, the countercurrent arrangement of vascular and tubular elements facilitates the trapping of urea and other solutes in the inner medulla, which in turn enables the formation of concentrated urine. Arteries and veins in the cortex are also arranged in a countercurrent fashion, as are descending and ascending vasa recta in the medulla. For countercurrent diffusion to occur, barriers to diffusion must be small. This appears to be characteristic of larger vessels in the renal cortex. There must also be gradients in the concentration of molecules between afferent and efferent vessels, with the transport of molecules possible in either direction. Such gradients exist for oxygen in both the cortex and medulla, but there is little evidence that large gradients exist for other molecules such as carbon dioxide, nitric oxide, superoxide, hydrogen sulfide, and ammonia. There is some experimental evidence for arterial-to-venous (AV) oxygen shunting. Mathematical models also provide evidence for oxygen shunting in both the cortex and medulla. However, the quantitative significance of AV oxygen shunting remains a matter of controversy. Thus, whereas the countercurrent arrangement of vasa recta in the medulla appears to have evolved as a consequence of the evolution of Henle's loop, the evolutionary significance of the intimate countercurrent arrangement of blood vessels in the renal cortex remains an enigma. Copyright © 2016 the American Physiological Society.

Preparative isolation and purification of astaxanthin from the microalga Chlorococcum sp. by high-speed counter-current chromatography.

PubMed

Li, H B; Chen, F

2001-08-03

High-speed counter-current chromatography was applied to the isolation and purification of astaxanthin from microalgae. The crude astaxanthin was obtained by extraction with organic solvents after the astaxanthin esters were saponified. Preparative high-speed counter-current chromatography with a two-phase solvent system composed of n-hexane-ethyl acetate-ethanol-water (5:5:6.5:3, v/v) was successfully performed yielding astaxanthin at 97% purity from 250 mg of the crude extract in a one-step separation.

Unusual seismogenic soft-sediment deformation structures in Cambrian epicratonic carbonate deposits, western Colorado, U.S.A

NASA Astrophysics Data System (ADS)

Myrow, P.; Chen, J.

2013-12-01

A wide variety of unusual penecontemporaneous deformation structures exist in grainstone and flat-pebble conglomerate beds of the Upper Cambrian strata, western Colorado, including slide scarps, thrusted beds, irregular blocks and internally deformed beds. Slide scarps are characterized by concave-up, sharp surfaces that truncate one or more underlying beds. Thrusted beds record movement of a part of a bed onto itself along a moderate to steeply inclined (generally 25°-40°) ramp. The hanging wall lenses in cases show fault-bend geometries, with either intact or mildly deformed bedding. Irregular bedded to internally deformed blocks isolated on generally flat upper bedding surfaces are similar in composition to the underlying beds. These features represent parts of beds that were detached, moved up onto, and some distances across, the laterally adjacent undisturbed bed surfaces. The blocks moved either at the sediment-water interface or intrastratally at shallow depths within overlying muddy deposits. Finally, internally deformed beds have large blocks, fitted fabrics of highly irregular fragments, and contorted lamination, which represent heterogeneous deformation, such as brecciation and liquefaction. The various deformation structures were most probably triggered by earthquakes, considering the nature of deformation (regional distribution of liquefaction structures, and the brittle segmentation and subsequent transportation of semi-consolidated beds) and the reactivation of Mesoproterozoic, crustal-scale shear zones in the central Rockies during the Late Cambrian. Features produced by initial brittle deformation are unusual relative to most reported seismites, and may represent poorly recognized to unrecognized seismogenic structures in the rock record.

Treatment of synthetic refinery wastewater in anoxic-aerobic sequential moving bed reactors and sulphur recovery.

PubMed

Mallick, Subrat Kumar; Chakraborty, Saswati

2017-11-10

Objective of the present study was to simultaneously biodegrade synthetic petroleum refinery wastewater containing phenol (750 mg/L), sulphide (750 mg/L), hydrocarbon (as emulsified diesel of 300 mg/L), ammonia-nitrogen (350 mg/L) at pH >9 in anoxic-aerobic sequential moving bed reactors. The optimum mixing speed of anoxic reactor was observed at 20 rpm and beyond that, removal rate remained constant. In anoxic reactor the minimum hydraulic retention time was observed to be 2 days for complete removal of sulphide, 40-50% removal of phenol and total hydrocarbons and 52% of sulphur recovery. The optimum HRT of aerobic moving bed reactor was observed as 16 h (total HRT of 64 h for anoxic and aerobic reactors) for complete removals of phenol, total hydrocarbons, COD (chemical oxygen demand) and ammonia-nitrogen with nitrification.

pH-zone-refining elution-extrusion countercurrent chromatography: Separation of hydroxyanthraquinones from Cassiae semen.

PubMed

Bu, Zhisi; Lv, Liqiong; Li, Xingnuo; Chu, Chu; Tong, Shengqiang

2017-11-01

Seven hydroxyanthraquinones were successfully separated from the traditional Chinese medicinal herb Cassiae semen by conventional and pH-zone-refining countercurrent chromatography with an environmentally friendly biphasic solvent system, in which elution-extrusion mode was investigated for pH-zone-refining countercurrent chromatography for the first time. A two-phase solvent system composed of n-hexane/ethyl acetate/ethanol/water (5:3:4:4, v/v/v/v) was used for the conventional countercurrent chromatography while the same system with a different volume ratio n-hexane/ethyl acetate/ethanol/water (3:5:2:6, v/v/v/v) was used for pH-zone-refining countercurrent chromatography, in which 20 mmol/L of trifluoroacetic acid was added in the organic phase as a retainer and 15 mmol/L of ammonia was added to the aqueous phase as an eluter. A 400 mg crude sample could be well separated by pH-zone-refining countercurrent chromatography, yielding 53 mg of aurantio-obtusin, 40 mg of chryso-obtusin, 18 mg of obtusin, 24 mg of obtusifolin, 10 mg of emodin, and 105 mg of the mixture of chrysophanol and physcion with a purity of over 95.8, 95.7, 96.9, 93.5, 97.4, 77.1, and 19.8%, as determined by high-performance liquid chromatography. Furthermore, the difference in elution sequence between conventional and pH-zone-refining mode was observed and discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Numerical and experimental investigation of downdraft gasification of woody residues.

PubMed

Simone, Marco; Nicolella, Cristiano; Tognotti, Leonardo

2013-04-01

A pilot scale throated downdraft gasifier was operated with vine prunings as feedstock to assess the effect of biomass loading rate on process performance. A distributed 1D model of mass and heat transfer and reactions was applied to aid the interpretation of experimental evidence. The model takes into account peculiar gasifier design features (air inlets and throat) and it reproduces satisfactorily the temperature profiles and the mass fluxes of gaseous species at different biomass loading rates. The integration of pilot-scale experiments and numerical simulations provides sound indications for the gasifier operation. In particular, simulations performed at different loading rates and feedstock humidity show that steady state operation and stable performance of the gasifier rely on the thermal balance between the enthalpy of cold biomass moving downward and the counter-current radiative heat fluxes moving upward from the oxidation zone. This balance can be destabilized by high loading rate and moisture contents. Copyright © 2013 Elsevier Ltd. All rights reserved.

Less common applications of simulated moving bed chromatography in the pharmaceutical industry.

PubMed

Huthmann, E; Juza, M

2005-10-21

Simulated moving bed (SMB) chromatography is often perceived in the pharmaceutical industry as chromatographic method for separating binary mixtures, like racemates. However, SMB can also be used for unbalanced separations, i.e. binary mixtures of varying compositions and multi-component mixtures. These less common application modes of isocratic SMB chromatography are exemplified for four different compounds (racemates and diastereomers) and discussed in view of the so-called 'triangle theory' from an industrial perspective.

Statistical description of flume experiments on mixed-size bed-load transport and bed armoring processes

NASA Astrophysics Data System (ADS)

Chen, D.; Zhang, Y.

2008-12-01

The objective of this paper is to describe the statistical properties of experiments on non-uniform bed-load transport as well as the mechanism of bed armoring processes. Despite substantial effort made over the last two decades, the ability to compute the bed-load flux in a turbulent system remains poor. The major obstacles include the poor understanding of the formation of armor lays on bed surfaces. Such a layer is much flow-resistible than the underlying material and therefore significantly inhibits sediment transport from the reach. To study the problem, we conducted a flume study for mixed sand/gravel sediments. We observed that aggregated sediment blocks were the most common characters in armor layers - the largest sizes resist hydraulic forces, while the smaller sizes add interlocking support and prevent loss of fine material through gaps between the larger particles. Fractional transport rates with the existing of armor layers were measured with time by sediment trapping method at the end of flume. To address the intermittent and time-varying behavior of bed-load transport during bed armoring processes, we investigated the probability distribution of the fractional bed-load transport rates, and the underlying dynamic model derived from the continuous time random walk framework. Results indicate that it is critical to consider the impact of armor layers when a flow is sufficient to move some of the finer particles and yet insufficient to move all the larger particles on a channel bed.

Flow-synchronous field motion refrigeration

DOEpatents

Hassen, Charles N.

2017-08-22

An improved method to manage the flow of heat in an active regenerator in a magnetocaloric or an electrocaloric heat-pump refrigeration system, in which heat exchange fluid moves synchronously with the motion of a magnetic or electric field. Only a portion of the length of the active regenerator bed is introduced to or removed from the field at one time, and the heat exchange fluid flows from the cold side toward the hot side while the magnetic or electric field moves along the active regenerator bed.

"Reagentless" flow injection determination of ammonia and urea using membrane separation and solid phase basification

NASA Technical Reports Server (NTRS)

Akse, J. R.; Thompson, J. O.; Sauer, R. L.; Atwater, J. E.

1998-01-01

Flow injection analysis instrumentation and methodology for the determination of ammonia and ammonium ions in an aqueous solution are described. Using in-line solid phase basification beds containing crystalline media. the speciation of ammoniacal nitrogen is shifted toward the un-ionized form. which diffuses in the gas phase across a hydrophobic microporous hollow fiber membrane into a pure-water-containing analytical stream. The two streams flow in a countercurrent configuration on opposite sides of the membrane. The neutral pH of the analytical stream promotes the formation of ammonium cations, which are detected using specific conductance. The methodology provides a lower limit of detection of 10 microgram/L and a dynamic concentration range spanning three orders of magnitude using a 315-microliters sample injection volume. Using immobilized urease to enzymatically promote the hydrolysis of urea to produce ammonia and carbon dioxide, the technique has been extended to the determination of urea.

Coupled large eddy simulation and discrete element model of bedload motion

NASA Astrophysics Data System (ADS)

Furbish, D.; Schmeeckle, M. W.

2011-12-01

We combine a three-dimensional large eddy simulation of turbulence to a three-dimensional discrete element model of turbulence. The large eddy simulation of the turbulent fluid is extended into the bed composed of non-moving particles by adding resistance terms to the Navier-Stokes equations in accordance with the Darcy-Forchheimer law. This allows the turbulent velocity and pressure fluctuations to penetrate the bed of discrete particles, and this addition of a porous zone results in turbulence structures above the bed that are similar to previous experimental and numerical results for hydraulically-rough beds. For example, we reproduce low-speed streaks that are less coherent than those over smooth-beds due to the episodic outflow of fluid from the bed. Local resistance terms are also added to the Navier-Stokes equations to account for the drag of individual moving particles. The interaction of the spherical particles utilizes a standard DEM soft-sphere Hertz model. We use only a simple drag model to calculate the fluid forces on the particles. The model reproduces an exponential distribution of bedload particle velocities that we have found experimentally using high-speed video of a flat bed of moving sand in a recirculating water flume. The exponential distribution of velocity results from the motion of many particles that are nearly constantly in contact with other bed particles and come to rest after short distances, in combination with a relatively few particles that are entrained further above the bed and have velocities approaching that of the fluid. Entrainment and motion "hot spots" are evident that are not perfectly correlated with the local, instantaneous fluid velocity. Zones of the bed that have recently experienced motion are more susceptible to motion because of the local configuration of particle contacts. The paradigm of a characteristic saltation hop length in riverine bedload transport has infused many aspects of geomorphic thought, including even bedrock erosion. In light of our theoretical, experimental, and numerical findings supporting the exponential distribution of bedload particle motion, the idea of a characteristic saltation hop should be scrapped or substantially modified.

How-to-Do-It: Countercurrent Heat Exchange in Vertebrate Limbs.

ERIC Educational Resources Information Center

Franklin, George B.; Plakke, Ronald K.

1988-01-01

Describes principals of physics that are manifested in simple biological systems of heat conservation structures. Outlines materials needed, data collection, analysis, and discussion questions for construction and operation of two models, one that is a countercurrent heat exchange model and one that is not. (RT)

New Adsorption Methods.

ERIC Educational Resources Information Center

Wankat, Phillip C.

1984-01-01

Discusses a simple method for following the movement of a solute in an adsorption or ion exchange system. This movement is used to study a variety of operational methods, including continuous flow and pulsed flow counter-current operations and simulated counter-current systems. Effect of changing thermodynamic variables is also considered. (JM)

Counter-current carbon dioxide purification of partially deacylated sunflower oil

USDA-ARS?s Scientific Manuscript database

High oleic sunflower oil was partially deacylated by propanolysis to produce a mixture of diglycerides and triglycerides. To remove by-product fatty acid propyl esters (FAPEs) from this reaction mixture, a liquid carbon dioxide (L-CO2) counter-current fractionation method was developed. The fracti...

Controlled biomass formation and kinetics of toluene degradation in a bioscrubber and in a reactor with a periodically moved trickle-bed.

PubMed

Wübker, S M; Laurenzis, A; Werner, U; Friedrich, C

1997-08-20

The kinetics of degradation of toluene from a model waste gas and of biomass formation were examined in a bioscrubber operated under different nutrient limitations with a mixed culture. The applicability of the kinetics of continuous cultivation of the mixed culture was examined for a special trickle-bed reactor with a periodically moved filter bed. The efficiency of toluene elimination of the bioscrubber was 50 to 57% and depended on the toluene mass transfer as evident from a constant productivity of 0.026 g dry cell weight/L . h over the dilution rate. Under potassium limitation the biomass productivity was reduced by 60% to 0.011 g dry cell weight/L . h at a dilution rate of 0.013/h. Conversely, at low dilution rates the specific toluene degradation rates increased. Excess biomass in a trickle-bed reactor causes reduction of interfacial area and mass transfer, and increase in pressure drop. To avoid these disadvantages, the trickle-bed was moved periodically and biomass was removed with outflowing medium. The concentration of steady state biomass fixed on polyamide beads decreased hyperbolically with the dilution rate. Also, the efficiency of toluene degradation decreased from 72 to 56% with increasing dilution rate while the productivity increased. Potassium limitation generally caused a reduction in biomass, productivity, and yield while the specific degradation increased with dilution rate. This allowed the application of the principles of the chemostat to the trickle-bed reactor described here, for toluene degradation from waste gases. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 686-692, 1997.

Elution-extrusion counter-current chromatography for the separation of two pairs of isomeric monoterpenes from Paeoniae Alba Radix.

PubMed

Chu, Chu; Zhang, Shidi; Tong, Shengqiang; Li, Xingnuo; Li, Qingyong; Yan, Jizhong

2015-09-01

In this work, a simple and efficient protocol for the rapid separation of two pairs of isomeric monoterpenes from Paeoniae Alba Radix was developed by combining macroporous resin and elution-extrusion counter-current chromatography. The crude extract was firstly subjected to a D101 macroporous resin column eluted with water and a series of different concentrations of ethanol. Then, effluents of 30 and 95% ethanol were collected as sample 1 and sample 2 for further counter-current chromatography purification. Finally, a pair of isomers, 96 mg of compound 1 and 48 mg of compound 2 with purities of 91.1 and 96.2%, respectively, was isolated from 200 mg of sample 1. The other pair of isomers, 14 mg of compound 3 and 8 mg of compound 4 with purities of 93.6 and 88.9%, respectively, was isolated from 48 mg of sample 2. Their purities were analyzed by high-performance liquid chromatography, and their chemical structures were identified by mass spectrometry and (1) H NMR spectroscopy. Compared to a normal counter-current chromatography separation, the separation time and solvent consumption of elution-extrusion counter-current chromatography were reduced while the resolutions were still good. The established protocol is promising for the separation of natural products with great disparity of content in herbal medicines. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Orifice plate for controlling solids flow, methods of use thereof and articles comprising the same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jukkola, Glen D.; Teigen, Bard C.

Disclosed herein is an orifice plate comprising one or more plates having orifices disposed therein; the orifices being operative to permit the flow of solids from a moving bed heat exchanger to a solids flow control system; where the orifice plate is downstream of a tube bundle of the moving bed heat exchanger and upstream of the solids flow control system and wherein the orifice plate is operative to evenly distribute the flow of solids in the solids flow control system.

Purification of Proteins From Cell-Culture Medium or Cell-Lysate by High-Speed Counter-Current Chromatography Using Cross-Axis Coil Planet Centrifuge

PubMed Central

Shibusawa, Yoichi; Ito, Yoichiro

2014-01-01

This review describes protein purifications from cell culture medium or cell-lysate by high speed counter-current chromatography using the cross-axis coil planet centrifuge. Purifications were performed using aqueous two phase systems composed of polyethylene glycols and dextrans. PMID:25360182

SIMULATION OF NON-AZEOTROPIC REFRIGERANT MIXTURES FOR USE IN A DUAL-CIRCUIT REFRIGERATOR/FREEZER WITH COUNTERCURRENT HEAT EXCHANGES

EPA Science Inventory

The paper discusses a refrigerator/freezer (RF) system that has two complete and independent refrigeration cycles for the two compartments. It uses a non-azeotropic refrigerant mixture (NARM) in each cycle and countercurrent heat exchangers throughout. This RF is housed in a stan...

Application of off-line two-dimensional high-performance countercurrent chromatography on the chloroform-soluble extract of Cuscuta auralis seeds.

PubMed

Rho, Taewoong; Yoon, Kee Dong

2018-05-01

In this study, the chloroform-soluble extract of Cuscuta auralis was separated successfully using off-line two-dimensional high-performance countercurrent chromatography, yielding a γ-pyrone, two alkaloids, a flavonoid, and four lignans. The first-dimensional countercurrent separation using a methylene chloride/methanol/water (11:6:5, v/v/v) system yielded three subfractions (fractions I-III). The second-dimensional countercurrent separations, conducted on fractions I-III using n-hexane/ethyl acetate/methanol/water/acetic acid (5:5:5:5:0, 3:7:3:7:0, and 1:9:1:9:0.01, v/v/v/v/v) systems, gave maltol (1), (-)-(13S)-cuscutamine (2), (+)-(13R)-cuscutamine (3), (+)-pinoresinol (4), (+)-epipinoresinol (5), kaempferol (6), piperitol (7), and (9R)-hydroxy-d-sesamin (8). To the best of our knowledge, maltol was identified for the first time in Cuscuta species. Furthermore, this report details the first full assignment of spectroscopic data of two cuscutamine epimers, (-)-(13S)-cuscutamine and (+)-(13R)-cuscutamine. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Correcting acoustic Doppler current profiler discharge measurement bias from moving-bed conditions without global positioning during the 2004 Glen Canyon Dam controlled flood on the Colorado River

USGS Publications Warehouse

Gartner, J.W.; Ganju, N.K.

2007-01-01

Discharge measurements were made by acoustic Doppler current profiler at two locations on the Colorado River during the 2004 controlled flood from Glen Canyon Dam, Arizona. Measurement hardware and software have constantly improved from the 1980s such that discharge measurements by acoustic profiling instruments are now routinely made over a wide range of hydrologic conditions. However, measurements made with instruments deployed from moving boats require reliable boat velocity data for accurate measurements of discharge. This is normally accomplished by using special acoustic bottom track pings that sense instrument motion over bottom. While this method is suitable for most conditions, high current flows that produce downstream bed sediment movement create a condition known as moving bed that will bias velocities and discharge to lower than actual values. When this situation exists, one solution is to determine boat velocity with satellite positioning information. Another solution is to use a lower frequency instrument. Discharge measurements made during the 2004 Glen Canyon controlled flood were subject to moving-bed conditions and frequent loss of bottom track. Due to site conditions and equipment availability, the measurements were conducted without benefit of external positioning information or lower frequency instruments. This paper documents and evaluates several techniques used to correct the resulting underestimated discharge measurements. One technique produces discharge values in good agreement with estimates from numerical model and measured hydrographs during the flood. ?? 2007, by the American Society of Limnology and Oceanography, Inc.

Structure and Variability of the Mesoscale Circulation in the Caribbean sea as Deduced From Satellite Altimetry

DTIC Science & Technology

1998-06-01

countercurrent along Costa Rica and Panama, which ends on the Colombian coast. This flow is usually called the Darien Countercurrent. Also, a counter flow...Marine Geology , vol. 68,25-52, 1985. Le Traon, P. Y., P. Gaspar, F. Bouyssel, and H. Makhmara, Using Topex / Poseidon Data to Enhance ERS-1 Data

Recovery of butanol by counter-current carbon dioxide fractionation with its potential application to butanol fermentation

USDA-ARS?s Scientific Manuscript database

A counter-current CO2 fractionation method was studied as a means to recover butanol (also known as 1-butanol or n-butanol) and other compounds that are typically obtained from biobutanol fermentation broth from aqueous solutions. The influence of operating parameters, such as solvent-to-feed ratio,...

Separation and characterisation of five polar herbicides using countercurrent chromatography with detection by negative ion electrospray ionisation mass spectrometry.

PubMed

Kidwell, H; Jones, J J; Games, D E

2001-01-01

Five polar herbicides were separated and characterised using high-speed analytical countercurrent chromatography (HSACCC) in conjunction with online electrospray mass spectrometry (ESI-MS). The countercurrent chromatography used a standard isocratic biphasic solvent system of hexane/ethyl acetate/methanol/water in reverse phase to effect the separation of these five environmentally important compounds. The chromatograph was coupled to a triple quadrupole mass spectrometer via a standard electrospray liquid chromatography interface that was able to give mass spectra in negative ion mode of each compound. Limits of detection are reported for this series of compounds along with representative negative ion ESI-MS data and calibrations for the separation. Copyright 2001 John Wiley & Sons, Ltd.

Counter-current convection in a volcanic conduit

NASA Astrophysics Data System (ADS)

Fowler, A. C.; Robinson, Marguerite

2018-05-01

Volcanoes of Strombolian type are able to maintain their semi-permanent eruptive states through the constant convective recycling of magma within the conduit leading from the magma chamber. In this paper we study the form of this convection using an analytic model of degassing two-phase flow in a vertical channel. We provide solutions for the flow at small Grashof and large Prandtl numbers, and we suggest that permanent steady-state counter-current convection is only possible if an initial bubbly counter-current flow undergoes a régime transition to a churn-turbulent flow. We also suggest that the magma in the chamber must be under-pressured in order for the flow to be maintained, and that this compromises the assumed form of the flow.

The Safety of Hospital Beds

PubMed Central

Gervais, Pierre; Pooler, Charlotte; Merryweather, Andrew; Doig, Alexa K.; Bloswick, Donald

2015-01-01

To explore the safety of the standard and the low hospital bed, we report on a microanalysis of 15 patients’ ability to ingress, move about the bed, and egress. The 15 participants were purposefully selected with various disabilities. Bed conditions were randomized with side rails up or down and one low bed with side rails down. We explored the patients’ use of the side rails, bed height, ability to lift their legs onto the mattress, and ability to turn, egress, and walk back to the chair. The standard bed was too high for some participants, both for ingress and egress. Side rails were used by most participants when entering, turning in bed, and exiting. We recommend that side rails be reconsidered as a means to facilitate in-bed movement, ingress, and egress. Furthermore, single deck height settings for all patients are not optimal. Low beds as a safety measure must be re-evaluated. PMID:28462302

Waste tyre pyrolysis: modelling of a moving bed reactor.

PubMed

Aylón, E; Fernández-Colino, A; Murillo, R; Grasa, G; Navarro, M V; García, T; Mastral, A M

2010-12-01

This paper describes the development of a new model for waste tyre pyrolysis in a moving bed reactor. This model comprises three different sub-models: a kinetic sub-model that predicts solid conversion in terms of reaction time and temperature, a heat transfer sub-model that calculates the temperature profile inside the particle and the energy flux from the surroundings to the tyre particles and, finally, a hydrodynamic model that predicts the solid flow pattern inside the reactor. These three sub-models have been integrated in order to develop a comprehensive reactor model. Experimental results were obtained in a continuous moving bed reactor and used to validate model predictions, with good approximation achieved between the experimental and simulated results. In addition, a parametric study of the model was carried out, which showed that tyre particle heating is clearly faster than average particle residence time inside the reactor. Therefore, this fast particle heating together with fast reaction kinetics enables total solid conversion to be achieved in this system in accordance with the predictive model. Copyright © 2010 Elsevier Ltd. All rights reserved.

Behavior of nitrogen removal in an aerobic sponge based moving bed biofilm reactor.

PubMed

Zhang, Xinbo; Song, Zi; Guo, Wenshan; Lu, Yanmin; Qi, Li; Wen, Haitao; Ngo, Huu Hao

2017-12-01

This study aims to investigate the behavior of nitrogen removal in an aerobic sponge based moving bed biofilm reactor by evaluating nitrification and denitrification rates of sponge biocarriers from three aerobic moving bed biofilm reactors (MBBRs) with filling ratios of 10% (R-10), 20% (R-20) and 30% (R-30). Results showed that the highest removal efficiencies of total nitrogen in three reactors were 84.5% (R-10), 93.6% (R-20) and 95.3% (R-30). Correspondingly, simultaneous nitrification and denitrification rate (SND) was 90.9%, 97.6% and 100%, respectively. Although R-20 had the highest attached-growth biomass (AGB) per gram of sponge compared to the other two reactors, R-30 showed the maximum ammonium oxidation rate (AOR) (2.1826±0.0717mgNH 4 + -N/gAGB/h) and denitrification rate (DNR) (5.0852±0.0891mgNO 3 - -N/gAGB/h), followed by R-20 and R-10. These results indicated AOR, DNR and AGB were affected by the filling ratio under the same operation mode. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combined fluidized bed retort and combustor

DOEpatents

Shang, Jer-Yu; Notestein, John E.; Mei, Joseph S.; Zeng, Li-Wen

1984-01-01

The present invention is directed to a combined fluidized bed retorting and combustion system particularly useful for extracting energy values from oil shale. The oil-shale retort and combustor are disposed side-by-side and in registry with one another through passageways in a partition therebetween. The passageways in the partition are submerged below the top of the respective fluid beds to preclude admixing or the product gases from the two chambers. The solid oil shale or bed material is transported through the chambers by inclining or slanting the fluidizing medium distributor so that the solid bed material, when fluidized, moves in the direction of the downward slope of the distributor.

Being a Nursing Aide; Student Manual.

ERIC Educational Resources Information Center

American Hospital Association, Chicago, IL.

Developed for students receiving on-the-job training as nursing aides, this illustrated manual contains these chapters: (1) Orientation, (2) Introduction to the Patient, (3) Your Working Environment, (4) The Patient's Unit: Making the Unoccupied Bed, (5) Lifting, Moving, and Transporting Patients: Making the Occupied Bed, (6) Personal Care of the…

Counter-current carbon dioxide extraction of fat from soy skim

USDA-ARS?s Scientific Manuscript database

This research aims to investigate the use of counter-current carbon dioxide extraction method as a means to reduce residual fat in soy skim after the enzyme-assisted aqueous extraction of soybeans. Extractions with liquid CO2 at 25°C and 10.34 MPa and supercritical CO2 at 50°C and 25.16 MPa are comp...

Isolation of a furan fatty acid from Hevea brasiliensis latex employing the combined use of pH-zone-refining and conventional countercurrent chromatography.

PubMed

Englert, Michael; Ulms, Kerstin; Wendlinger, Christine; Vetter, Walter

2016-02-01

Furan fatty acids are valuable and bioactive minor fatty acids that usually contribute <0.1% to the fatty acid content of food samples. Their biological role still remains unclear as authentic furan fatty acid standards are not readily available and thorough experimental studies verifying the relevance of furan fatty acids are thus virtually impossible. An efficient protocol for the isolation of the furan fatty acid 9-(3-methyl-5-pentylfuran-2-yl)-nonanoic acid from hydrolyzed and centrifuged latex of Hevea brasiliensis was developed using countercurrent chromatography. A first run using pH-zone-refining countercurrent chromatography provided 48.4 mg of 9-(3-methyl-5-pentylfuran-2-yl)-nonanoic acid from 210 mg latex extract in a purity of 95%. The purity was increased to 99% by means of one second run in conventional countercurrent chromatography mode. The Structure and purity of 9-(3-methyl-5-pentylfuran-2-yl)-nonanoic acid were determined by gas chromatography coupled to mass spectrometry and (1)H and (13)C NMR spectroscopy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of acuity-adaptable rooms on flow of patients and delivery of care.

PubMed

Hendrich, Ann L; Fay, Joy; Sorrells, Amy K

2004-01-01

Delayed transfers of patients between nursing units and lack of available beds are significant problems that increase costs and decrease quality of care and satisfaction among patients and staff. To test whether use of acuity-adaptable rooms helps solve problems with transfers of patients, satisfaction levels, and medical errors. A pre-post method was used to compare the effects of environmental design on various clinical and financial measures. Twelve outcome-based questions were formulated as the basis for inquiry. Two years of baseline data were collected before the unit moved and were compared with 3 years of data collected after the move. Significant improvements in quality and operational cost occurred after the move, including a large reduction in clinician handoffs and transfers; reductions in medication error and patient fall indexes; improvements in predictive indicators of patients' satisfaction; decrease in budgeted nursing hours per patient day and increased available nursing time for direct care without added cost; increase in patient days per bed, with a smaller bed base (number of beds per patient days). Some staff turnover occurred during the first year; turnover stabilized thereafter. Data in 5 key areas (flow of patients and hospital capacity, patients' dissatisfaction, sentinel events, mean length of stay, and allocation of nursing productivity) appear to be sufficient to test the business case for future investment in partial or complete replication of this model with appropriate populations of patients.

[Application of ultrasound counter currentextraction in patent of traditional Chinese medicine].

PubMed

Miao, Yan-ni; Wu, Bin; Yue, Xue-lian

2015-07-01

The patent information of ultrasound countercurrent extraction used in traditional Chinese medicine was analyzed in this paper by the samples from Derwent World Patent Database (DWPI) and the Chinese Patent Abstracts Database (CNABS). The application of ultrasound countercurrent was discussed with the patent applicant,the amount of the annual distribution, and the pharmaceutical raw materials and other aspects. While the technical parameters published in the patent was deeply analyzed, such as material crushing, extraction solvent, extraction time and temperature, extraction equipment and ultrasonic frequency. Thought above research, various technical parameters of ultrasound countercurrent extraction used in traditional Chinese was summarize. The analysis conclusion of the paper can be used in discovering the technical advantages, optimizing extraction conditions, and providing a reference to extraction technological innovation of traditional Chinese medicine.

Supply-Limited Bedforms in a Gravel-Sand Transition

NASA Astrophysics Data System (ADS)

Venditti, J. G.; Nittrouer, J. A.; Humphries, R. P.; Allison, M. A.

2009-12-01

Rivers often exhibit an abrupt transition from gravel to sand-bedded conditions as river channel slopes decrease. A distinct suite of bedforms has been observed through these reaches where sand supply to the bed is limited. The suite of bedforms includes a sequence of sand ribbons, barchans, and channel spanning dunes as sediment supply increases in the downstream direction. While these bedforms have been extensively documented in laboratory channels, there are relatively few observations of this sequence of supply-limited bedforms from large natural channels. Here we examine the sequence through the gravel-sand transition of the Fraser River in Southwestern British Columbia. We mapped the bed using multi-beam swath-bathymetry (Reson 8101 Seabat) at high flow (~9,000 m3s-1) immediately following a high peak flow of 11,800 m3s-1 in June 2007 The bed material grades from >70% gravel to entirely sand through the reach. The bedforms follow the expected sequence where sand ribbons and barchanoid forms cover the bed where it is primarily gravel. Channel spanning dunes form as the sand bed coverage increases. Bedform dimensions (height and length) increase moving downstream as the sand moving on the bed increases. Supply-unlimited bedforms typically scale with the flow depth where the height is 1/5 the flow depth. The bedforms developed over the gravel are undersized by this criterion. Downstream, where the bed is dominantly sand, bedforms do scale with flow depth. These data highlight the dominant role sediment supply can play in bedform morphology and scaling, confirming patterns observed in laboratory data.

Granular controls on the dispersion of bed load tracers

NASA Astrophysics Data System (ADS)

Jerolmack, D. J.; Martin, R. L.; Phillips, C. B.

2014-12-01

Coarse particles are transported in a river as bed load, i.e., they move in frequent contact with and are supported by the granular bed. This movement is typically intermittent and may be described by a series of steps are rests, the distributions of which determine particle dispersion. Laboratory and field studies of bed load tracer dispersion have reported sub- and super-diffusive behavior, both of which have been successfully reproduced with stochastic transport models. Although researchers have invoked heavy-tailed step lengths as the cause of anomalous dispersion, most observations report thin-tailed distributions. Little attention has been paid to rest periods, and stochastic transport models have not been connected to the underlying mechanics of particle motion. Based on theoretical and experimental evidence, we argue that step lengths are thin-tailed and do not control the longterm dispersion of bed load tracers; they are determined by momentum balance between the fluid and solid. Using laboratory experiments with both marbles and natural sediments, we demonstrate that the rest time distribution is power law, and argue that this distribution controls asymptotic dispersion. Observed rest times far exceed any hydrodynamic timescale. Experiments reveal that rest times of deposited particles are governed by fluctuations in river bed elevation; in particular, the return time for the bed to scour to the base of a deposited particle. Stochastic fluctuations in bed elevation are describable by an Ornstein-Uhlenbeck (mean-reverting random walk) model that contains two parameters, which we show are directly related to the granular shear rate and range of bed elevation fluctuations, respectively. Combining these results with the theory of asymmetric random walks (particles only move downstream), we predict superdiffusive behavior that is in quantitative agreement with our observations of tracer dispersion in a natural river.

Questing activity in bed bug populations: male and female responses to host signals.

PubMed

Aak, Anders; Rukke, Bjørn A; Soleng, Arnulf; Rosnes, Marte K

2014-09-01

A large-arena bioassay is used to examine sex differences in spatiotemporal patterns of bed bug Cimex lectularius L. behavioural responses to either a human host or CO 2 gas. After release in the centre of the arena, 90% of newly-fed bed bugs move to hiding places in the corners within 24 h. They require 3 days to settle down completely in the arena, with generally low activity levels and the absence of responses to human stimuli for 5 days. After 8-9 days, persistent responses can be recorded. Sex differences are observed, in which females are more active during establishment, respond faster after feeding, expose themselves more than males during the daytime, and respond more strongly to the host signal. The number of bed bugs that rest in harbourages is found to vary significantly according to light setting and sex. Both sexes stay inside harbourages more in daylight compared with night, and males hide more than females during the daytime but not during the night. The spatial distribution of the bed bugs is also found to change with the presence of CO 2 , and peak aggregation around the odour source is observed after 24 min. Both male and female bed bugs move from hiding places or the border of the arena toward the centre where CO 2 is released. Peak responses are always highest during the night. Bed bug behaviour and behaviour-regulating features are discussed in the context of control methods.

Questing activity in bed bug populations: male and female responses to host signals

PubMed Central

Aak, Anders; Rukke, Bjørn A; Soleng, Arnulf; Rosnes, Marte K

2014-01-01

A large-arena bioassay is used to examine sex differences in spatiotemporal patterns of bed bug Cimex lectularius L. behavioural responses to either a human host or CO2 gas. After release in the centre of the arena, 90% of newly-fed bed bugs move to hiding places in the corners within 24 h. They require 3 days to settle down completely in the arena, with generally low activity levels and the absence of responses to human stimuli for 5 days. After 8–9 days, persistent responses can be recorded. Sex differences are observed, in which females are more active during establishment, respond faster after feeding, expose themselves more than males during the daytime, and respond more strongly to the host signal. The number of bed bugs that rest in harbourages is found to vary significantly according to light setting and sex. Both sexes stay inside harbourages more in daylight compared with night, and males hide more than females during the daytime but not during the night. The spatial distribution of the bed bugs is also found to change with the presence of CO2, and peak aggregation around the odour source is observed after 24 min. Both male and female bed bugs move from hiding places or the border of the arena toward the centre where CO2 is released. Peak responses are always highest during the night. Bed bug behaviour and behaviour-regulating features are discussed in the context of control methods. PMID:26166936

Influence of liquid and gas flow rates on sulfuric acid mist removal from air by packed bed tower

PubMed Central

2012-01-01

The possible emission of sulfuric acid mists from a laboratory scale, counter-current packed bed tower operated with a caustic scrubbing solution was studied. Acid mists were applied through a local exhaust hood. The emissions from the packed bed tower were monitored in three different categories of gas flow rate as well as three liquid flow rates, while other influencing parameters were kept almost constant. Air sampling and sulfuric acid measurement were carried out iso-kinetically using USEPA method 8. The acid mists were measured by the barium-thorin titration method. According to the results when the gas flow rate increased from 10 L/s to 30 L/s, the average removal efficiency increased significantly (p < 0.001) from 76.8 ± 1.8% to 85.7 ± 1.2%. Analysis of covariance method followed by Tukey post-hoc test of 92 tests did not show a significant change in removal efficiency between liquid flow rates of 1.5, 2.5 and 3.5 L/min (p = 0.811). On the other hand, with fixed pressure loss across the tower, by increasing the liquid/gas (L/G) mass ratio, the average removal efficiency decreased significantly (p = 0.001) from 89.9% at L/G of <2 to 83.1% at L/G of 2–3 and further to 80.2% at L/G of >3, respectively. L/G of 2–3 was recommended for designing purposes of a packed tower for sulfuric acid mists and vapors removal from contaminated air stream. PMID:23369487

Increasing the capacity for treatment of chemical plant wastewater by replacing existing suspended carrier media with Kaldnes Moving Bed media at a plant in Singapore.

PubMed

Wessman, F G; Yan Yuegen, E; Zheng, Q; He, G; Welander, T; Rusten, B

2004-01-01

The Kaldnes biomedia K1, which is used in the patented Kaldnes Moving Bed biofilm process, has been tested along with other types of biofilm carriers for biological pretreatment of a complex chemical industry wastewater. The main objective of the test was to find a biofilm carrier that could replace the existing suspended carrier media and at the same time increase the capacity of the existing roughing filter-activated sludge plant by 20% or more. At volumetric organic loads of 7.1 kg COD/m3/d the Kaldnes Moving Bed process achieved much higher removal rates and much lower effluent concentrations than roughing filters using other carriers. The Kaldnes roughing stage achieved more than 85% removal of organic carbon and more than 90% removal of BOD5 at the tested organic load, which was equivalent to a specific biofilm surface area load of 24 g COD/m2/d. Even for the combined roughing filter-activated sludge process, the Kaldnes carriers outperformed the other carriers, with 98% removal of organic carbon and 99.6% removal of BOD5. The Kaldnes train final effluent concentrations were only 22 mg FOC/L and 7 mg BOD5/L. Based on the successful pilot testing, the full-scale plant was upgraded with Kaldnes Moving Bed roughing filters. During normal operation the upgraded plant has easily met the discharge limits of 100 mg COD/L and 50 mg SS/L. For the month of September 2002, with organic loads between 100 and 115% of the design load for the second half of the month, average effluent concentrations were as low as 9 mg FOC/L, 51 mg COD/L and 12 mg SS/L.

Salmon Spawning Effects on Streambed Stability

NASA Astrophysics Data System (ADS)

Buxton, T. H.; Buffington, J. M.; Yager, E.; Fremier, A. K.; Hassan, M. A.

2014-12-01

Female salmon build nests ("redds") in streambeds to protect their eggs from predation and damage by bed scour. During spawning, streambed material is mixed, fine sediment is winnowed downstream, and sediment is moved into a tailspill mound resembling the shape of a dune. Redd surfaces are coarser and better sorted than unspawned beds, which is thought to increase redd stability because larger grains are heavier and harder to move and sorting leads to higher friction angles for grain mobility. However, spawning also loosens sediment and creates topography that accelerates flow, both of which may increase particle mobility. We address factors controlling the relative stability of redds and unspawned beds using simulated salmon redds and water worked ("unspawned") beds composed of mixed-grain surfaces in a laboratory flume. Results show that simulated spawning lowered packing resistance to particle mobility on redds by an average of 32-39% compared to unspawned beds. Reductions in packing were sufficient to counter the higher inherent stability of relatively coarse, well sorted grains on redds, overall reducing critical shear stress by 8-20% relative to unspawned beds. In addition, boundary shear stress was 13-41% higher on redds due to flow convergence over the tailspill structure. Finally, redd instability relative to unspawned beds was observed in visual measurements of grain mobility, where bed-averaged shear stress was 22% lower at incipient motion and 29% lower at the discharge that mobilized all grain sizes on redds. Results of these complementary observations, along with sediment mass transport rates being nearly five times higher on a redd than an unspawned bed, indicate that redds are unstable compared to unspawned beds. Given these findings, further research is needed to investigate linkages between spawning disturbance and streambed mobility that may affect salmon reproduction in streams, and to assess whether a certain level of bed disturbance from spawning is required to restore ecosystem functions in streams with threatened populations of salmon.

The dispersal of the Amazon's water

NASA Technical Reports Server (NTRS)

Muller-Karger, Frank E.; Mcclain, Charles R.; Richardson, Philip L.

1988-01-01

New information obtained with NASA's Coastal Zone Color Scanner and with drifting buoys reveals that the discharge of the Amazon is carried offshore around a retroflection of the North Brazil Current and into the North Equatorial Countercurrent towards Africa between June and January each year. From about February to May, the countercurrent and the retroflection weaken or vanish, and Amazon water flows northwestward toward the Caribbean Sea.

Reacting flow studies in a dump combustor: Enhanced volumetric heat release rates and flame anchorability

NASA Astrophysics Data System (ADS)

Behrens, Alison Anne

Reacting flow studies in a novel dump combustor facility focused on increasing volumetric heat release rates, under stable burning conditions, and understanding the physical mechanisms governing flame anchoring in an effort to extend range and maneuverability of compact, low drag, air-breathing engines. Countercurrent shear flow was enhanced within the combustor as the primary control variable. Experiments were performed burning premixed JP10/air and methane/air in a dump combustor using reacting flow particle image velocimetry (PIV) and chemiluminescence as the primary diagnostics. Stable combustion studies burning lean mixtures of JP10/air aimed to increase volumetric heat release rates through the implementation of countercurrent shear control. Countercurrent shear flow was produced by creating a suction flow from a low pressure cavity connected to the dump combustor via a gap directly below the trailing edge. Chemiluminescence measurements showed that enhancing countercurrent shear within the combustor doubles volumetric heat release rates. PIV measurements indicate that counterflow acts to increase turbulent kinetic energy while maintaining constant strain rates. This acts to increase flame surface area through flame wrinkling without disrupting the integrity of the flame. Flame anchorability is one of the most important fundamental aspects to understand when trying to enhance turbulent combustion in a high-speed engine without increasing drag. Studies burning methane/air mixtures used reacting flow PIV to study flame anchoring. The operating point with the most stable flame anchor exhibited a correspondingly strong enthalpy flux of products into reactants via a single coherent structure positioned downstream of the step. However, the feature producing a strong flame anchor, i.e. a single coherent structure, also is responsible for combustion instabilities, therefore making this operating point undesirable. Counterflow control was found to create the best flow features for stable, robust, compact combustion. Enhancing countercurrent shear flow within a dump combustor enhances burning rates, provides a consistent pump of reaction-initiating combustion products required for sustained combustion, while maintaining flow three dimensionality needed to disrupt combustion instabilities. Future studies will focus on geometric and control scenarios that further reduce drag penalties while creating these same flow features found with countercurrent shear thus producing robust operating points.

Packed bed reactor for photochemical .sup.196 Hg isotope separation

DOEpatents

Grossman, Mark W.; Speer, Richard

1992-01-01

Straight tubes and randomly oriented pieces of tubing having been employed in a photochemical mercury enrichment reactor and have been found to improve the enrichment factor (E) and utilization (U) compared to a non-packed reactor. One preferred embodiment of this system uses a moving bed (via gravity) for random packing.

Hydrogen production from coal

NASA Technical Reports Server (NTRS)

1975-01-01

The gasification reactions necessary for the production of hydrogen from montana subbituminous coal are presented. The coal composition is given. The gasifier types mentioned include: suspension (entrained) combustion; fluidized bed; and moving bed. Each gasification process is described. The steam-iron process, raw and product gas compositions, gasifier feed quantities, and process efficiency evaluations are also included.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khare, G.P.; Delzer, G.A.; Kubicek, D.H.

Phillips Z-Sorb sorbents have been evaluated successfully as regenerable sorbents for hydrogen sulfide in the fuel gas that is produced in a clean coal technology power plant. Tests have been carried out in fixed-,moving-, and fluid-bed applications. The fixed-bed tests completed at the Morgantown Energy Technology Center showed that Phillips Z-Sorb sorbent performed better than zinc titanate. The performance of Phillips Z-Sorb sorbent in a moving-bed application was very encouraging. The sorbent flowed well, H{sub 2}S was reduced to less than 50 ppm at the absorber outlet over long periods and post-test analysis of the sorbent indicated very low sulfatemore » levels at the regenerator exit. The fluidizable version of Phillips Z-Sorb sorbent was tested in Research Triangle Institutes`s high temperature, high pressure, semi-bath, fluidized-bed reactor system. in a life cycle test consisting of 50 cycles of sulfidation and regeneration, this sorbent exhibited excellent activity and regenerability. The sulfur loading was observed to be 90 + percent of the theoretical capacity. The sorbent consistently demonstrated a sharp regeneration profile with no evidence of sulfate accumulation. 7 refs., 7 fig., 5 tabs.« less

Lagrangian and Eulerian description of bed-load particle kinematics

NASA Astrophysics Data System (ADS)

Ballio, Francesco; Sadabadi, Seyed Abbas Hosseini; Pokrajac, Dubravka; Radice, Alessio

2016-04-01

The motion of bed-load sediment particles transported by a flow can be analyzed within a Lagrangian or an Eulerian framework. In the former case, we consider the particles as individual objects in motion and we study their kinematic properties. The latter approach is instead referred to suitably chosen control volumes. Quantities describing sediment motion in the two frameworks are different, and the relationships among the two approaches are not straightforward. In this work, we intend to discuss the kinematic properties of sediment transport: first, a set of quantities is univocally defined; then, relationships among different representations are explored. Proof-of-concept results presented in the study are from a recent experiment involving weak bed-load sediment transport, where the moving particles were released over a fixed rough bed. The bulk flow velocity was 1.4 times the critical value for incipient particle motion, and particles were mostly moving by rolling and sliding, with limited saltation. The particle motion was filmed from the top and the measurements were conducted by image-based methods, obtaining extensive samples of virtually-instantaneous quantities.

Moving granular-bed filter development program, Option III: Development of moving granular-bed filter technology for multi-contaminant control. Task 14: Test plan; Topical report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haas, J.C.; Olivo, C.A.; Wilson, K.B.

1994-04-01

An experimental test plan has been prepared for DOE/METC review and approval to develop a filter media suitable for multi-contaminant control in granular-bed filter (GBF) applications. The plan includes identification, development, and demonstration of methods for enhanced media morphology, chemical reactivity, and mechanical strength. The test plan includes media preparation methods, physical and chemical characterization methods for fresh and reacted media, media evaluation criteria, details of test and analytical equipment, and test matrix of the proposed media testing. A filter media composed of agglomerated limestone and clay was determined to be the best candidate for multi-contaminate control in GBF operation.more » The combined limestone/clay agglomerate has the potential to remove sulfur and alkali species, in addition to particulate, and possibly halogens and trace heavy metals from coal process streams.« less

Inert gas clearance from tissue by co-currently and counter-currently arranged microvessels

PubMed Central

Lu, Y.; Michel, C. C.

2012-01-01

To elucidate the clearance of dissolved inert gas from tissues, we have developed numerical models of gas transport in a cylindrical block of tissue supplied by one or two capillaries. With two capillaries, attention is given to the effects of co-current and counter-current flow on tissue gas clearance. Clearance by counter-current flow is compared with clearance by a single capillary or by two co-currently arranged capillaries. Effects of the blood velocity, solubility, and diffusivity of the gas in the tissue are investigated using parameters with physiological values. It is found that under the conditions investigated, almost identical clearances are achieved by a single capillary as by a co-current pair when the total flow per tissue volume in each unit is the same (i.e., flow velocity in the single capillary is twice that in each co-current vessel). For both co-current and counter-current arrangements, approximate linear relations exist between the tissue gas clearance rate and tissue blood perfusion rate. However, the counter-current arrangement of capillaries results in less-efficient clearance of the inert gas from tissues. Furthermore, this difference in efficiency increases at higher blood flow rates. At a given blood flow, the simple conduction-capacitance model, which has been used to estimate tissue blood perfusion rate from inert gas clearance, underestimates gas clearance rates predicted by the numerical models for single vessel or for two vessels with co-current flow. This difference is accounted for in discussion, which also considers the choice of parameters and possible effects of microvascular architecture on the interpretation of tissue inert gas clearance. PMID:22604885

Radiolarian indicators of El Nino and anti-El Nino events in Holocene sediments of Santa Barbara basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weinheimer, A.L.

Radiolarian distributions and physical oceanographic data from the Santa Barbara basin indicate the following. Strong anti-El Nino periods can be characterized by (1) intermediate radiolarian density, (2) high percentage of transition-central radiolarian fauna, and (3) low percentage and number of warm-water radiolarian fauna. This distribution pattern is attributed to strong wind-driven upwelling and reduced northward transport by the California Countercurrent during anti-El Nino periods. Strong El Nino periods are typically (1) high in radiolarian density, and (2) low in percentage but high in number of warm-water fauna. This distribution is attributed to reduced wind-driven upwelling, enhanced northward countercurrent transport, andmore » geostrophic doming of the cold-water masses in the shear zone between the California Current and California Countercurrent.« less

System design study to reduce capital and operating cost of a moving distributor, AFB advanced concept - comparison with an oil-fired boiler. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mah, C.S.; West, L.K.; Anderson, R.E.

1985-12-01

The Aerojet Energy Conversion Company, under contract with the United States Department of Energy, has performed a comparative economic study of the Aerojet Universal Atmospheric Fluidized Bed Combustion (UAFBC) system and a coventional atmospheric fluidized bed combustion (AFBC) system. The program title, ''System Design Study to Reduce Capital and Operating Cost and Bench Scale Testing of a Moving Distributor, AFB Concept,'' is a good description of the general objective of the program. The specific objective was to compare the UAFBC with the conventional AFBC in terms of normalized steam cost. The boilers were designed for 150,00 lb/hr of steam atmore » 650 psig and 750/sup 0/F. The reference coal used in the analysis was Pittsburgh No. 8 coal with a sulfur content of 4.3% and a higher heating value of 12,919 Bru/lb. The analysis assumed a plant life of 20 years and a discount rate of 15%. The UAFBC systems included the usual elements of the conventional cola-fired AFBC steam plant, but the coal preparation sysbsystem for the UAFBC was considerably simpler because the system can use ''run-of-mine'' coal. The UAFBC boiler itself consisted of a staged-combustion fluidized-bed, superimposed over a static bed, the latter supported by a moving distributor. It incorporated a fines burnup combustor, an entrained reciculating gas cleanup bed, and conventional convection boiler. The key features of the UAFBC design were: High fuel flexibility; low NO/sub x/ emission; and superior turndown capability. 30 refs., 52 figs., 12 tabs.« less

Modeling integrated fixed-film activated sludge and moving-bed biofilm reactor systems II: evaluation.

PubMed

Boltz, Joshua P; Johnson, Bruce R; Daigger, Glen T; Sandino, Julian; Elenter, Deborah

2009-06-01

A steady-state model presented by Boltz, Johnson, Daigger, and Sandino (2009) describing integrated fixed-film activated sludge (IFAS) and moving-bed biofilm reactor (MBBR) systems has been demonstrated to simulate, with reasonable accuracy, four wastewater treatment configurations with published operational data. Conditions simulated include combined carbon oxidation and nitrification (both IFAS and MBBR), tertiary nitrification MBBR, and post denitrification IFAS with methanol addition as the external carbon source. Simulation results illustrate that the IFAS/MBBR model is sufficiently accurate for describing ammonia-nitrogen reduction, nitrate/nitrite-nitrogen reduction and production, biofilm and suspended biomass distribution, and sludge production.

Down-flow moving-bed gasifier with catalyst recycle

DOEpatents

Halow, John S.

1999-01-01

The gasification of coal and other carbonaceous materials by an endothermic gasification reaction is achieved in the presence of a catalyst in a down-flow, moving-bed gasifier. Catalyst is removed along with ash from the gasifier and is then sufficiently heated in a riser/burner by the combustion of residual carbon in the ash to volatilize the catalyst. This volatilized catalyst is returned to the gasifier where it uniformly contacts and condenses on the carbonaceous material. Also, the hot gaseous combustion products resulting from the combustion of the carbon in the ash along with excess air are introduced into the gasifier for providing heat energy used in the endothermic reaction.

Staged fluidized-bed combustion and filter system

DOEpatents

Mei, Joseph S.; Halow, John S.

1994-01-01

A staged fluidized-bed combustion and filter system for substantially reducing the quantity of waste through the complete combustion into ash-type solids and gaseous products. The device has two fluidized-bed portions, the first primarily as a combustor/pyrolyzer bed, and the second as a combustor/filter bed. The two portions each have internal baffles to define stages so that material moving therein as fluidized beds travel in an extended route through those stages. Fluidization and movement is achieved by the introduction of gases into each stage through a directional nozzle. Gases produced in the combustor/pyrolyzer bed are permitted to travel into corresponding stages of the combustor/filter bed through screen filters that permit gas flow but inhibit solids flow. Any catalyst used in the combustor/filter bed is recycled. The two beds share a common wall to minimize total volume of the system. A slightly modified embodiment can be used for hot gas desulfurization and sorbent regeneration. Either side-by-side rectangular beds or concentric beds can be used. The system is particularly suited to the processing of radioactive and chemically hazardous waste.

Preparative isolation of a cytotoxic principle of a forest mushroom Suillus luteus by sodium dodecyl sulfate based "salting-in" countercurrent chromatography.

PubMed

Yang, Zhi; Hu, Xueqian; Wu, Shihua

2016-02-01

In the course of screening new anticancer natural products, an edible forest mushroom Suillus luteus (L. Ex Franch). Gray was found to have potent cytotoxicity against several human cancer cells. However, the lipophilic sample made some countercurrent chromatography solvent systems emulsify, which caused difficulties in the separation of its cytotoxic components. Here, we found that the addition of an organic salt sodium dodecyl sulfate could efficiently shorten the settling time of the mushroom sample solutions by eliminating the emulsification of two-phase solvent systems. Moreover, we found that sodium dodecyl sulfate could play a new "salting-in" role and made the partition coefficients of the solutes decrease with the increased concentrations. Thus, a sodium dodecyl sulfate based salting-in countercurrent chromatography method has been successfully established for the first time for preparative isolation of a cytotoxic principle of the mushroom. The active component was identified as isosuillin. Whole results indicated that sodium dodecyl sulfate could be used as an efficient salting-in reagent for two-phase solvent system selection and targeted countercurrent chromatography isolation. It is very useful for current natural products isolation and drug discovery. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Validation of a Mechanistic Model for Non-Invasive Study of Ecological Energetics in an Endangered Wading Bird with Counter-Current Heat Exchange in its Legs.

PubMed

Fitzpatrick, Megan J; Mathewson, Paul D; Porter, Warren P

2015-01-01

Mechanistic models provide a powerful, minimally invasive tool for gaining a deeper understanding of the ecology of animals across geographic space and time. In this paper, we modified and validated the accuracy of the mechanistic model Niche Mapper for simulating heat exchanges of animals with counter-current heat exchange mechanisms in their legs and animals that wade in water. We then used Niche Mapper to explore the effects of wading and counter-current heat exchange on the energy expenditures of Whooping Cranes, a long-legged wading bird. We validated model accuracy against the energy expenditure of two captive Whooping Cranes measured using the doubly-labeled water method and time energy budgets. Energy expenditure values modeled by Niche Mapper were similar to values measured by the doubly-labeled water method and values estimated from time-energy budgets. Future studies will be able to use Niche Mapper as a non-invasive tool to explore energy-based limits to the fundamental niche of Whooping Cranes and apply this knowledge to management decisions. Basic questions about the importance of counter-current exchange and wading to animal physiological tolerances can also now be explored with the model.

Validation of a Mechanistic Model for Non-Invasive Study of Ecological Energetics in an Endangered Wading Bird with Counter-Current Heat Exchange in its Legs

PubMed Central

Fitzpatrick, Megan J.; Mathewson, Paul D.; Porter, Warren P.

2015-01-01

Mechanistic models provide a powerful, minimally invasive tool for gaining a deeper understanding of the ecology of animals across geographic space and time. In this paper, we modified and validated the accuracy of the mechanistic model Niche Mapper for simulating heat exchanges of animals with counter-current heat exchange mechanisms in their legs and animals that wade in water. We then used Niche Mapper to explore the effects of wading and counter-current heat exchange on the energy expenditures of Whooping Cranes, a long-legged wading bird. We validated model accuracy against the energy expenditure of two captive Whooping Cranes measured using the doubly-labeled water method and time energy budgets. Energy expenditure values modeled by Niche Mapper were similar to values measured by the doubly-labeled water method and values estimated from time-energy budgets. Future studies will be able to use Niche Mapper as a non-invasive tool to explore energy-based limits to the fundamental niche of Whooping Cranes and apply this knowledge to management decisions. Basic questions about the importance of counter-current exchange and wading to animal physiological tolerances can also now be explored with the model. PMID:26308207

Bubbling behavior of a fluidized bed of fine particles caused by vibration-induced air inflow.

PubMed

Matsusaka, Shuji; Kobayakawa, Murino; Mizutani, Megumi; Imran, Mohd; Yasuda, Masatoshi

2013-01-01

We demonstrate that a vibration-induced air inflow can cause vigorous bubbling in a bed of fine particles and report the mechanism by which this phenomenon occurs. When convective flow occurs in a powder bed as a result of vibrations, the upper powder layer with a high void ratio moves downward and is compressed. This process forces the air in the powder layer out, which leads to the formation of bubbles that rise and eventually burst at the top surface of the powder bed. A negative pressure is created below the rising bubbles. A narrow opening at the bottom allows the outside air to flow into the powder bed, which produces a vigorously bubbling fluidized bed that does not require the use of an external air supply system.

CFD simulation of MSW combustion and SNCR in a commercial incinerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xia, Zihong; Li, Jian; Wu, Tingting

Highlights: • Presented a CFD scheme for modeling MSW incinerator including SNCR process. • Performed a sensitivity analysis of SNCR operating conditions. • Non-uniform distributions of gas velocity, temperature and NO{sub x} in the incinerator. • The injection position of reagent was critical for a desirable performance of SNCR. • A NSR 1.5 was recommended as a compromise of NO{sub x} reduction rates and NH{sub 3} slip. - Abstract: A CFD scheme was presented for modeling municipal solid waste (MSW) combustion in a moving-grate incinerator, including the in-bed burning of solid wastes, the out-of-bed burnout of gaseous volatiles, and themore » selective non-catalytic reduction (SNCR) process between urea (CO(NH{sub 2}){sub 2}) and NO{sub x}. The in-bed calculations provided 2-D profiles of the gas–solid temperatures and the gas species concentrations along the bed length, which were then used as inlet conditions for the out-of-bed computations. The over-bed simulations provided the profiles of incident radiation heat flux on the top of bed. A 3-dimensional benchmark simulation was conducted with a 750 t/day commercial incinerator using the present coupling scheme incorporating with a reduced SNCR reduction mechanism. Numerical tests were performed to investigate the effects of operating parameters such as injection position, injection speed and the normalized stoichiometric ratio (NSR) on the SNCR performance. The simulation results showed that the distributions of gas velocity, temperature and NO{sub x} concentration were highly non-uniform, which made the injection position one of the most sensitive operating parameters influencing the SNCR performance of moving grate incinerators. The simulation results also showed that multi-layer injections were needed to meet the EU2000 standard, and a NSR 1.5 was suggested as a compromise of a satisfactory NO{sub x} reduction and reasonable NH{sub 3} slip rates. This work provided useful guides to the design and operation of SNCR process in moving-grate incinerators.« less

Aquatic habitat mapping with an acoustic doppler current profiler: Considerations for data quality

USGS Publications Warehouse

Gaeuman, David; Jacobson, Robert B.

2005-01-01

When mounted on a boat or other moving platform, acoustic Doppler current profilers (ADCPs) can be used to map a wide range of ecologically significant phenomena, including measures of fluid shear, turbulence, vorticity, and near-bed sediment transport. However, the instrument movement necessary for mapping applications can generate significant errors, many of which have not been inadequately described. This report focuses on the mechanisms by which moving-platform errors are generated, and quantifies their magnitudes under typical habitat-mapping conditions. The potential for velocity errors caused by mis-alignment of the instrument?s internal compass are widely recognized, but has not previously been quantified for moving instruments. Numerical analyses show that even relatively minor compass mis-alignments can produce significant velocity errors, depending on the ratio of absolute instrument velocity to the target velocity and on the relative directions of instrument and target motion. A maximum absolute instrument velocity of about 1 m/s is recommended for most mapping applications. Lower velocities are appropriate when making bed velocity measurements, an emerging application that makes use of ADCP bottom-tracking to measure the velocity of sediment particles at the bed. The mechanisms by which heterogeneities in the flow velocity field generate horizontal velocities errors are also quantified, and some basic limitations in the effectiveness of standard error-detection criteria for identifying these errors are described. Bed velocity measurements may be particularly vulnerable to errors caused by spatial variability in the sediment transport field.

Phase-field simulation of counter-current spontaneous imbibition in a fractured heterogeneous porous medium

NASA Astrophysics Data System (ADS)

Rokhforouz, M. R.; Akhlaghi Amiri, H. A.

2017-06-01

Spontaneous imbibition is well-known to be one of the most effective processes of oil recovery in fractured reservoirs. However, the detailed pore-scale mechanisms of the counter-current imbibition process and the effects of different fluid/rock parameters on this phenomenon have not yet been deeply addressed. This work presents the results of a new pore-level numerical study of counter-current spontaneous imbibition, using coupled Cahn-Hilliard phase field and Navier-Stokes equations, solved by a finite element method. A 2D fractured medium was constructed consisting of a nonhomogeneous porous matrix, in which the grains were represented by an equilateral triangular array of circles with different sizes and initially saturated with oil, and a fracture, adjacent to the matrix, initially saturated with water and supported by low rate water inflow. Through invasion of water into the matrix, oil drops were expelled one by one from the matrix to the fracture, and in the matrix, water progressed by forming capillary fingerings, with characteristics corresponding to the experimental observations. The effects of wettability, viscosity ratio, and interfacial tension were investigated. In strongly water-wet matrix, with grain contact angles of θ < π/8, different micro-scale mechanisms were successfully captured, including oil film thinning and rupture, fluids' contact line movement, water bridging, and oil drop detachment. It was notified that there was a specific grain contact angle for this simulated model, θ = π/4, above it, matrix oil recovery was negligible by imbibition, while below it, the imbibition rate and oil recovery were significantly increased by decreasing the contact angle. In simulated mixed wet models, water, coming from the fracture, just invaded the neighboring water-wet grains; the water front was stopped moving as it met the oil-wet grains or wide pores/throats. Increasing water-oil interfacial tension, in the range of 0.005-0.05 N/m, resulted in both higher rate of imbibition and higher ultimate oil recovery. Changing the water-oil viscosity ratio (M), in the range of 0.1-10, had a negligible effect on the imbibition rate, while due to co-effects of capillary fingering and viscous mobility ratio, the model with M = 1 had relatively higher ultimate oil recovery.

Practical Experience of Discharge Measurement in Flood Conditions with ADP

NASA Astrophysics Data System (ADS)

Vidmar, A.; Brilly, M.; Rusjan, S.

2009-04-01

Accurate discharge estimation is important for an efficient river basin management and especially for flood forecasting. The traditional way of estimating the discharge in hydrological practice is to measure the water stage and to convert the recorded water stage values into discharge by using the single-valued rating curve .Relationship between the stage and discharge values of the rating curve for the extreme events are usually extrapolated by using different mathematical methods and are not directly measured. Our practice shows that by using the Accoustic Doppler Profiler (ADP) instrument we can record the actual relation between the water stage and the flow velocity at the occurrence of flood waves very successfully. Measurement in flood conditions it is not easy task, because of high water surface velocity and large amounts of sediments in the water and floating objects on the surface like branches, bushes, trees, piles and others which can also easily damage ADP instrument. We made several measurements in such extreme events on the Sava River down to the nuclear power plant Kr\\vsko where we have install fixed cable way. During the several measurement with traditional "moving-boat" measurement technique a mowing bed phenomenon was clearly seen. Measuring flow accurately using ADP that uses the "moving-boat" technique, the system needs a reference against which to relate water velocities to. This reference is river bed and must not move. During flood events we detected difficulty finding a static bed surface to which to relate water velocities. This is caused by motion of the surface layer of bed material or also sediments suspended in the water near bed very densely. So these traditional »moving-boat« measurement techniques that we normally use completely fail. Using stationary measurement method to making individual velocity profile measurements, using an Acoustic Doppler Profiler (ADP), at certain time at fixed locations across the width of a stream gave us much better results. We use Stationary Measurement Software from SONTEK ADP manufacture to provide the tools to make USGS/ISO/WMO "Mid-Section Method" measurements using an ADP. We have ADP with 3.0 MHz which gave us 0,15m cell size in which is capable to gauge from 0,3m to a maximum depth of 6m. The beauty of using the Stationary Measurement Software is not only to overcome common moving-bed problems, but that gave us possibility to measure at depth beyond the range of the instrument. The water depth at certain profile can be inputted with known values of cross section and velocities are then extrapolated to the bed with use of velocity profile power-law equation. In practice the other good advantage to use this method is that we can repeat each profile of measurement if we detected some anomalies in the profile of measured velocities or in the case that we must quickly remove instrument from location because of floating destroying material.

Undesirable dispersal of eggs and early-stage nymphs of the bed bug Hemiptera: cimicidae) by static electricity and air currents

USDA-ARS?s Scientific Manuscript database

Movement of whole live insects or other small arthropods attributed to static electricity has been reported only rarely. While viewing bed bugs in plastic or glass Petri dishes using a dissecting microscope, individual eggs and early stage nymphs were occasionally observed to move suddenly and rapid...

Swanky Suites, More Students?

ERIC Educational Resources Information Center

Supiano, Beckie

2008-01-01

Leaders at Indiana University of Pennsylvania had heard the horror stories: Students would be accepted here, visit the campus, take one look at the outdated dormitories, and decide to go someplace else. Something had to be done. So they made the bold move to replace all student housing, bed for bed--at a cost of $270-million. The public university…

Low shear stress gravel-bed river

USGS Publications Warehouse

Milhous, Robert T.

1997-01-01

A low stress gravel bed river is a river where the cross-sectional average dimensionless shear stress (??*) rarely exceeds 0.047. That is the case for the Gunnison River below Delta in Western Colorado. The cross-sectional average ??* in the Gunnison River has not exceeded 0.047, except at one cross section during one year, in the 87 years of record. A ??* of 0.047 is the critical ??* in the bed-load equation considered to be most applicable to gravel/cobble bed rivers (the Meyer-Peter, Mueller equation). According to this equation, there has been no bed-material movement in the Gunnison River since 1920; in fact there has been bed-material movement and this movement is biologically important. Bed-material is moved when the ??* is 0.016 or larger. Streamflows that cause a ??* of at least 0.016 maintain the aquatic habitat in a low shear stress river.

Countercurrent flow absorber and desorber

DOEpatents

Wilkinson, William H.

1984-01-01

Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system.

Countercurrent heat exchange and thermoregulation during blood-feeding in kissing bugs

PubMed Central

Lahondère, Chloé; Insausti, Teresita C; Belev, George; Pereira, Marcos H

2017-01-01

Blood-sucking insects experience thermal stress at each feeding event on endothermic vertebrates. We used thermography to examine how kissing-bugs Rhodnius prolixus actively protect themselves from overheating. During feeding, these bugs sequester and dissipate the excess heat in their heads while maintaining an abdominal temperature close to ambient. We employed a functional-morphological approach, combining histology, µCT and X-ray-synchrotron imaging to shed light on the way these insects manage the flow of heat across their bodies. The close alignment of the circulatory and ingestion systems, as well as other morphological characteristics, support the existence of a countercurrent heat exchanger in the head of R. prolixus, which decreases the temperature of the ingested blood before it reaches the abdomen. This kind of system has never been described before in the head of an insect. For the first time, we show that countercurrent heat exchange is associated to thermoregulation during blood-feeding. PMID:29157359

Countercurrent Separation of Natural Products: An Update

PubMed Central

2015-01-01

This work assesses the current instrumentation, method development, and applications in countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC), collectively referred to as countercurrent separation (CCS). The article provides a critical review of the CCS literature from 2007 since our last review (J. Nat. Prod.2008, 71, 1489–1508), with a special emphasis on the applications of CCS in natural products research. The current state of CCS is reviewed in regard to three continuing topics (instrumentation, solvent system development, theory) and three new topics (optimization of parameters, workflow, bioactivity applications). The goals of this review are to deliver the necessary background with references for an up-to-date perspective of CCS, to point out its potential for the natural product scientist, and thereby to induce new applications in natural product chemistry, metabolome, and drug discovery research involving organisms from terrestrial and marine sources. PMID:26177360

Application of an efficient strategy based on liquid-liquid extraction, high-speed counter-current chromatography, and preparative HPLC for the rapid enrichment, separation, and purification of four anthraquinones from Rheum tanguticum.

PubMed

Chen, Tao; Liu, Yongling; Zou, Denglang; Chen, Chen; You, Jinmao; Zhou, Guoying; Sun, Jing; Li, Yulin

2014-01-01

This study presents an efficient strategy based on liquid-liquid extraction, high-speed counter-current chromatography, and preparative HPLC for the rapid enrichment, separation, and purification of four anthraquinones from Rheum tanguticum. A new solvent system composed of petroleum ether/ethyl acetate/water (4:2:1, v/v/v) was developed for the liquid-liquid extraction of the crude extract from R. tanguticum. As a result, emodin, aloe-emodin, physcion, and chrysophanol were greatly enriched in the organic layer. In addition, an efficient method was successfully established to separate and purify the above anthraquinones by high-speed counter-current chromatography and preparative HPLC. This study supplies a new alternative method for the rapid enrichment, separation, and purification of emodin, aloe-emodin, physcione, and chrysophanol. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Separation of alkaloids in tea by high-speed counter-current chromatography].

PubMed

Yuan, L; Fu, R; Zhang, T; Deng, J; Li, X

1998-07-01

Alkaloids extracted from the green tea were separated by high-speed counter-current chromatography. A series of experiments have been performed to investigate effects of different solvent system. A system of CHCl3-CH3OH-NaH2PO4(23 mmol/L) = (4:3:2) was selected, in which the upper phase was used as the stationary phase, and the lower phase as mobile phase. When acidity of solvent system is pH 5.6, three chemical components are very efficiently isolated by one injection of 50 mg sample mixture. Analyzing the eluted fractions by TLC, we know that one is caffeine, and the other is theophylline. In comparing the separation results by high-speed counter-current chromatography with those by TLC, the advantages of this method is verified. It should find wide applications of this technology for the separation of crude mixture of plant components.

Bubbling behavior of a fluidized bed of fine particles caused by vibration-induced air inflow

PubMed Central

Matsusaka, Shuji; Kobayakawa, Murino; Mizutani, Megumi; Imran, Mohd; Yasuda, Masatoshi

2013-01-01

We demonstrate that a vibration-induced air inflow can cause vigorous bubbling in a bed of fine particles and report the mechanism by which this phenomenon occurs. When convective flow occurs in a powder bed as a result of vibrations, the upper powder layer with a high void ratio moves downward and is compressed. This process forces the air in the powder layer out, which leads to the formation of bubbles that rise and eventually burst at the top surface of the powder bed. A negative pressure is created below the rising bubbles. A narrow opening at the bottom allows the outside air to flow into the powder bed, which produces a vigorously bubbling fluidized bed that does not require the use of an external air supply system. PMID:23378921

Down-flow moving-bed gasifier with catalyst recycle

DOEpatents

Halow, J.S.

1999-04-20

The gasification of coal and other carbonaceous materials by an endothermic gasification reaction is achieved in the presence of a catalyst in a down-flow, moving-bed gasifier. Catalyst is removed along with ash from the gasifier and is then sufficiently heated in a riser/burner by the combustion of residual carbon in the ash to volatilize the catalyst. This volatilized catalyst is returned to the gasifier where it uniformly contacts and condenses on the carbonaceous material. Also, the hot gaseous combustion products resulting from the combustion of the carbon in the ash along with excess air are introduced into the gasifier for providing heat energy used in the endothermic reaction. 1 fig.

Evaluation of center-cut separations applying simulated moving bed chromatography with 8 zones.

PubMed

Santos da Silva, Francisco Vitor; Seidel-Morgenstern, Andreas

2016-07-22

Different multi-column options to perform continuous chromatographic separations of ternary mixtures have been proposed in order to overcome limitations of batch chromatography. One attractive option is given by simulated moving bed chromatography (SMB) with 8 zones, a process that offers uninterrupted production, and, potentially, improved economy. As in other established ternary separation processes, the separation sequence is crucial for the performance of the process. This problem is addressed here by computing and comparing optimal performances of the two possibilities assuming linear adsorption isotherms. The conclusions are presented in a decision tree which can be used to guide the selection of system configuration and operation. Copyright © 2016 Elsevier B.V. All rights reserved.

Polyethylene Based Materials for Biofilm Carriers Used in Wastewater Treatment

NASA Astrophysics Data System (ADS)

Moga, I. C.; Iordache, O. I.; Petrescu, G.; Pricop, F.; Dumitrescu, I.

2018-06-01

The moving bed biofilm technology is based on biofilm carriers on which consortia of microorganisms attach, develop and grow. Around the world are known many biofilm carrier variants made of varied materials. The most common materials are based on polyethylene since this material has a close to water density. The authors propose a novel biofilm carrier to be used in tertiary treatment for tannery and paper-mill wastewaters. The biological treatment is based on fungal activity. The selected fungal strains will be grown on innovative polyethylene carriers containing cellulose. The carrier will be designed to be exploited in a moving bed bioreactor and to favour fungal growth in the presence of competing bacteria.

Basic Education for Adults: Pathways to College and Careers for Washington's Emerging Workforce. Washington's Community and Technical Colleges

ERIC Educational Resources Information Center

Washington State Board for Community and Technical Colleges, 2015

2015-01-01

This brief describes the Basic Education for Adults (BEdA) programs that bridge the gap between school and work, thereby creating pathways to college and careers for Washington's emerging workforce. BEdA programs teach foundational skills--reading, writing, math, technology and English language--so adults can move through college and into…

Countercurrent flow absorber and desorber

DOEpatents

Wilkinson, W.H.

1984-10-16

Countercurrent flow absorber and desorber devices are provided for use in absorption cycle refrigeration systems and thermal boosting systems. The devices have increased residence time and surface area resulting in improved heat and mass transfer characteristics. The apparatuses may be incorporated into open cycle thermal boosting systems in which steam serves both as the refrigerant vapor which is supplied to the absorber section and as the supply of heat to drive the desorber section of the system. 9 figs.

Separation of phenolic acids from sugarcane rind by online solid-phase extraction with high-speed counter-current chromatography.

PubMed

Geng, Ping; Fang, Yingtong; Xie, Ronglong; Hu, Weilun; Xi, Xingjun; Chu, Qiao; Dong, Genlai; Shaheen, Nusrat; Wei, Yun

2017-02-01

Sugarcane rind contains some functional phenolic acids. The separation of these compounds from sugarcane rind is able to realize the integrated utilization of the crop and reduce environment pollution. In this paper, a novel protocol based on interfacing online solid-phase extraction with high-speed counter-current chromatography (HSCCC) was established, aiming at improving and simplifying the process of phenolic acids separation from sugarcane rind. The conditions of online solid-phase extraction with HSCCC involving solvent system, flow rate of mobile phase as well as saturated extent of absorption of solid-phase extraction were optimized to improve extraction efficiency and reduce separation time. The separation of phenolic acids was performed with a two-phase solvent system composed of butanol/acetic acid/water at a volume ratio of 4:1:5, and the developed online solid-phase extraction with HSCCC method was validated and successfully applied for sugarcane rind, and three phenolic acids including 6.73 mg of gallic acid, 10.85 mg of p-coumaric acid, and 2.78 mg of ferulic acid with purities of 60.2, 95.4, and 84%, respectively, were obtained from 150 mg sugarcane rind crude extracts. In addition, the three different elution methods of phenolic acids purification including HSCCC, elution-extrusion counter-current chromatography and back-extrusion counter-current chromatography were compared. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gradient x Isocratic Elution CCC on the Isolation of Verbascoside and Other Phenylethanoids: Influence of the Complexity of the Matrix.

PubMed

Leitão, Gilda Guimarães; Pinto, Shaft Correa; de Oliveira, Danilo Ribeiro; Timoteo, Patrícia; Guimarães, Michelle Guedes; Cordova, Wilmer H Perera; Leitão, Suzana Guimarães

2015-11-01

Verbascoside is a phenylethanoid glycoside widely distributed in nature, especially among the order Lamiales, occurring in numerous plants that are constituents of folk medicine preparations. This natural compound, previously isolated by our group from the ethyl acetate extract of Lantana trifolia using the gradient approach in countercurrent chromatography, was now isolated from the butanol extract of the same plant and from Lippia alba f. intermedia (Verbenaceae) using countercurrent chromatography in either gradient or isocratic elution modes. The ethyl acetate extract of L. alba, rich in phenylethanoids and flavonoids, was fractionated using countercurrent chromatography in the step-gradient elution approach. The four-step solvent system was composed of n-hexane-ethyl acetate-n-butanol-water (4 : 10 : X : 10), where X = 1 (solvent system A), 3 (solvent system B), 5 (solvent system C), and 7 (solvent system D), and allowed for the isolation of verbascoside along with other phenylethanoids and flavonoids from both plants. Verbascoside and 2'-O-β-apiosylverbascoside were further isolated from the n-butanol extract of L. trifolia using the solvent system ethyl acetate-n-butanol-water 10 : 2 : 10 on an isocratic run. The difference in the complexity of the two plant extracts demanded different purification steps, which included a second high-speed countercurrent chromatography purification using the isocratic elution mode. Georg Thieme Verlag KG Stuttgart · New York.

Preparative separation of six rhynchophylla alkaloids from Uncaria macrophylla wall by pH-zone refining counter-current chromatography.

PubMed

Zhang, Qinghai; Lin, Changhu; Duan, Wenjuan; Wang, Xiao; Luo, Aiqin

2013-12-12

pH-Zone refining counter-current chromatography was successfully applied to the preparative isolation and purification of six alkaloids from the ethanol extracts of Uncaria macrophylla Wall. Because of the low content of alkaloids (about 0.2%, w/w) in U. macrophylla Wall, the target compounds were enriched by pH-zone refining counter-current chromatography using a two-phase solvent system composed of petroleum ether-ethyl acetate-isopropanol-water (2:6:3:9, v/v), adding 10 mM triethylamine in organic stationary phase and 5 mM hydrochloric acid in aqueous mobile phase. Then pH-zone refining counter-current chromatography using the other two-phase solvent system was used for final purification. Six target compounds were finally isolated and purified by following two-phase solvent system composed of methyl tert-butyl ether (MTBE)-acetonitrile-water (4:0.5:5, v/v), adding triethylamine (TEA) (10 mM) to the organic phase and HCl (5 mM) to aqueous mobile phase. The separation of 2.8 g enriched total alkaloids yielded 36 mg hirsutine, 48 mg hirsuteine, 82 mg uncarine C, 73 mg uncarine E, 163 mg rhynchophylline, and 149 mg corynoxeine, all with purities above 96% as verified by HPLC Their structures were identified by electrospray ionization-mass spectrometry (ESI-MS) and 1H-NMR spectroscopy.

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.

Performance Study of Chromium (VI) Removal in Presence of Phenol in a Continuous Packed Bed Reactor by Escherichia coli Isolated from East Calcutta Wetlands

PubMed Central

Chakraborty, Bhaswati; Indra, Suvendu; Hazra, Ditipriya; Betai, Rupal; Ray, Lalitagauri; Basu, Srabanti

2013-01-01

Organic pollutants, like phenol, along with heavy metals, like chromium, are present in various industrial effluents that pose serious health hazard to humans. The present study looked at removal of chromium (VI) in presence of phenol in a counter-current continuous packed bed reactor packed with E. coli cells immobilized on clay chips. The cells removed 85% of 500 mg/L of chromium (VI) from MS media containing glucose. Glucose was then replaced by 500 mg/L phenol. Temperature and pH of the MS media prior to addition of phenol were 30°C and 7, respectively. Hydraulic retention times of phenol- and chromium (VI)-containing synthetic media and air flow rates were varied to study the removal efficiency of the reactor system. Then temperature conditions of the reactor system were varied from 10°C to 50°C, the optimum being 30°C. The pH of the media was varied from pH 1 to pH 12, and the optimum pH was found to be 7. The maximum removal efficiency of 77.7% was achieved for synthetic media containing phenol and chromium (VI) in the continuous reactor system at optimized conditions, namely, hydraulic retention time at 4.44 hr, air flow rate at 2.5 lpm, temperature at 30°C, and pH at 7. PMID:24073400

Pneumatic transportation of dispersed medium through a vertical tube immersed into a fluidized bed

NASA Astrophysics Data System (ADS)

Krasnykh, V. Yu.; Korolev, V. N.; Ostrovskaya, A. V.; Nagornov, S. A.

2013-11-01

We discuss the technical problem of how to transport granular material in a vertical direction from the underlying section of a multistage apparatus containing a fluidized bed to an upper section through tubes immersed into the fluidized bed without additional expenditures of energy. The intensity with which the dispersed medium (a mixture of gas and fuel particles) moves through the tube and the mass flowrate of particles are determined by the ratio between the hydraulic resistances of dispersed medium inside the tube and of the fluidized bed outside of it. In turn, this ratio depends on the fluidization number W (W = w s/ w 0, where w s is the seepage velocity and w 0 is the fluidization commencement velocity) and on the tube immersing depth into the bed.

Use of Inert Gases and Carbon Monoxide to Study the Possible Influence of Countercurrent Exchange on Passive Absorption from the Small Bowel

PubMed Central

Bond, John H.; Levitt, David G.; Levitt, Michael D.

1974-01-01

The purpose of the present study was to quantitate the influence of countercurrent exchange on passive absorption of highly diffusible substances from the small intestine of the rabbit. The absorption of carbon monoxide, which is tightly bound to hemoglobin and therefore cannot exchange, was compared to the absorption of four unbound gases (H2, He, CH4, and 133Xe), which should exchange freely. The degree to which the observed absorption of the unbound gases falls below that predicted from CO absorption should provide a quantitative measure of countercurrent exchange. CO uptake at high luminal Pco is flow-limited and, assuming that villus and central hemoglobin concentrations are equal, the flow that equilibrates with CO (Fco) was calculated to equal 7.24 ml/min/100 g. The observed absorption rate of the unbound gases was from two to four times greater than would have been predicted had their entire uptake been accounted for by equilibration with Fco. This is the opposite of what would occur if countercurrent exchange retarded absorption of the unbound gases. The unbound gases have both flow- and diffusion-limited components, and Fco should account for only the fraction of absorption that is flow limited. A simple model of perfusion and diffusion made it possible to calculate the fraction of the total uptake of unbound gases that was flow limited. This fraction of the total observed absorption rate was still about 1.8 times greater than predicted by CO absorption. A possible explanation for this discrepancy is that plasma skimming reduces the hemoglobin of villus blood to about 60% of that of central blood. Thus, Fco is actually about 1.7 times greater than initially calculated, and with this correction, there is close agreement between the predicted and observed rates of absorption of each of the unbound gases. We conclude that countercurrent exchange does not influence passive absorption under the conditions of this study. PMID:4436431

Conical coils counter-current chromatography for preparative isolation and purification of tanshinones from Salvia miltiorrhiza Bunge.

PubMed

Liang, Junling; Meng, Jie; Guo, Mengzhe; Yang, Zhi; Wu, Shihua

2013-05-03

Modern counter-current chromatography (CCC) originated from the helical coil planet centrifuge. Recently, spiral coils were found to possess higher separation efficiency in both the retention of stationary phase and solutes resolution than other CCC coils like the helical and toroidal coils used on type-J CCC and cross-axis CCC. In this work, we built a novel conical coil CCC for the preparative isolation and purification of tanshinones from Salvia miltiorrhiza Bunge. The conical coils were wound on three identical upright tapered holders in head-to-tail and left-handed direction and connected in series. Compared with helical and spiral coil CCC, conical coil CCC not only placed CCC column in a two-dimensional centrifugal field, but also provided a potential centrifugal force gradient both in axial and radial directions. The extra centrifugal gradient made mobile phase move faster and enabled CCC much higher retention of stationary phase and better resolution. As a result, higher efficiency has been obtained with the solvent system of hexane-ethyl acetate-methanol-water (HEMWat) with the volume ratio of 5:5:7:3 by using conical coil CCC apparatus. Four tanshinones, including cryptotanshinone (1), tanshinone I (2), 1,2-dihydrotanshinquinone (3) and tanshinone IIA (4), were well resolved from 500mg to 1g crude samples with high purity. Furthermore, the conical coil CCC can make a much higher solid phase retention, which makes it to be a powerful separation tool with high throughput. This is the first report about conical coil CCC for separation of tanshinones and it may also be an important advancement for natural products isolation. Copyright © 2013 Elsevier B.V. All rights reserved.

Separation of Calcium Isotopes by Counter-Current Electro-Migration in Molten Salts; SEPARATION DES ISOTOPES DU CALCIUM PAR ELECTRO-MIGRATION A CONTRECOURANT EN SELS FONDUS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menes, F.; Dirian, G.; Roth, E.

1962-01-01

The method of counter-current electromigration in molten salts was applied to CaBr/sub 2/ with an alkali metal bromide added to the cathode compartment. Enrichments on Ca/sup 46/ greater than a factor of two were obtained at the anode. The mass effect was found to be about 0.06. An estimation of the cost of energy for a process based on this method was made. (auth)

Hybrid indirect/direct contactor for thermal management of counter-current processes

DOEpatents

Hornbostel, Marc D.; Krishnan, Gopala N.; Sanjurjo, Angel

2018-03-20

The invention relates to contactors suitable for use, for example, in manufacturing and chemical refinement processes. In an aspect is a hybrid indirect/direct contactor for thermal management of counter-current processes, the contactor comprising a vertical reactor column, an array of interconnected heat transfer tubes within the reactor column, and a plurality of stream path diverters, wherein the tubes and diverters are configured to block all straight-line paths from the top to bottom ends of the reactor column.

Heat Treating Apparatus

DOEpatents

De Saro, Robert; Bateman, Willis

2002-09-10

Apparatus for heat treating a heat treatable material including a housing having an upper opening for receiving a heat treatable material at a first temperature, a lower opening, and a chamber therebetween for heating the heat treatable material to a second temperature higher than the first temperature as the heat treatable material moves through the chamber from the upper to the lower opening. A gas supply assembly is operatively engaged to the housing at the lower opening, and includes a source of gas, a gas delivery assembly for delivering the gas through a plurality of pathways into the housing in countercurrent flow to movement of the heat treatable material, whereby the heat treatable material passes through the lower opening at the second temperature, and a control assembly for controlling conditions within the chamber to enable the heat treatable material to reach the second temperature and pass through the lower opening at the second temperature as a heated material.

Comparison of two methods of numerical tracking of the soil contamination dynamics during a leak from a pipeline

NASA Astrophysics Data System (ADS)

Kosterina, E. A.

2018-01-01

The situation of leakage of a polluting liquid from a longitudinal crack of the pipeline lying on the ground surface is considered. The two-dimensional nonstationary mathematical model is based on the mass balance equation in terms of pressure, which is satisfied in a domain with an unknown moving boundary. This area corresponds to the area of contaminated zone. A function characterizing the region of action of the equation is introduced, which makes it possible to obtain the formulation of the problem in a fixed domain. Two types of finite-difference approximation of the problem statement are proposed. They differ by approximation of the convective term. Counter-current approximation and approximation along characteristics are used. The results of computational experiments, which are in favor of using the method of characteristics, are presented. The methods application is illustrated by an example of spread of oil pollution.

Using autoregressive integrated moving average (ARIMA) models to predict and monitor the number of beds occupied during a SARS outbreak in a tertiary hospital in Singapore.

PubMed

Earnest, Arul; Chen, Mark I; Ng, Donald; Sin, Leo Yee

2005-05-11

The main objective of this study is to apply autoregressive integrated moving average (ARIMA) models to make real-time predictions on the number of beds occupied in Tan Tock Seng Hospital, during the recent SARS outbreak. This is a retrospective study design. Hospital admission and occupancy data for isolation beds was collected from Tan Tock Seng hospital for the period 14th March 2003 to 31st May 2003. The main outcome measure was daily number of isolation beds occupied by SARS patients. Among the covariates considered were daily number of people screened, daily number of people admitted (including observation, suspect and probable cases) and days from the most recent significant event discovery. We utilized the following strategy for the analysis. Firstly, we split the outbreak data into two. Data from 14th March to 21st April 2003 was used for model development. We used structural ARIMA models in an attempt to model the number of beds occupied. Estimation is via the maximum likelihood method using the Kalman filter. For the ARIMA model parameters, we considered the simplest parsimonious lowest order model. We found that the ARIMA (1,0,3) model was able to describe and predict the number of beds occupied during the SARS outbreak well. The mean absolute percentage error (MAPE) for the training set and validation set were 5.7% and 8.6% respectively, which we found was reasonable for use in the hospital setting. Furthermore, the model also provided three-day forecasts of the number of beds required. Total number of admissions and probable cases admitted on the previous day were also found to be independent prognostic factors of bed occupancy. ARIMA models provide useful tools for administrators and clinicians in planning for real-time bed capacity during an outbreak of an infectious disease such as SARS. The model could well be used in planning for bed-capacity during outbreaks of other infectious diseases as well.

Numerical modelling of bedload sediment transport

NASA Astrophysics Data System (ADS)

Langlois, Vincent J.

2010-05-01

We present a numerical study of sediment transport in the bedload regime. Classical bedload transport laws only describe the variation of the vertically integrated flux of grains as a function of the Shields number. However, these relations are only valid if the moving layer of the bed is at equilibrium with the external flow. Besides, they do not contain enough information for many geomorphological applications. For instance, understanding inertial effects in the moving bed requires models that are able to account for the variability of hydrodynamical conditions, and the discrete nature of the sediment material. We developped a numerical modelling of the behaviour of a three-dimensional bed of grains sheared by a unidirectional fluid flow. These simulations are based on a combination of discrete and continuum approaches: sediment particles are modelled by hard spheres interacting through simple contact forces, whereas the fluid flow is described by a 'mean field' model. Both the drag exerted on grains by the fluid and the retroactive effect of the presence of grains on the flow are accounted for, allowing the system to converge to its equilibrium state (no assumption is made on the fluid velocity profile inside the layer of moving grains). Above the motion threshold, the variation of the flux of grains in the steady state is found to vary like the cube of the Shields number (as predicted by Bagnold). Besides, our simulations allow us to obtain new insights into the detailed mechanisms of bedload transport, by giving access to non-integral quantities, such as the trajectories of each individual grains, the detailed velocity and packing fraction profiles inside the granular bed, etc. It is therefore possible to investigate some effects that are not accounted for in usual continuum models, such as the polydispersity of grains, the ageing of the bed, the response to a variation of the flowrate, etc.

Simultaneous separation of three isomeric sennosides from senna leaf (Cassia acutifolia) using counter-current chromatography.

PubMed

Park, Sait Byul; Kim, Yeong Shik

2015-10-01

Senna leaf is widely consumed as tea to treat constipation or to aid in weight loss. Sennoside A, A1 , and B are dirheinanthrone glucosides that are abundant and the bioactive constituents in the plant. They are isomers that refer to the (R*R*), (S*S*), and (R*S*) forms of protons on C-10 and C-10' centers and it is difficult to refine them individually due to their structural similarities. The new separation method using counter-current chromatography successfully purified sennoside A, A1 , and B from senna leaf (Cassia acutifolia) while reversed-phase medium-pressure liquid chromatography yielded sennoside A only. n-Butanol/isopropanol/water (5:1:6, v/v/v) was selected as the solvent system for counter-current chromatography operation, and the partition coefficients were carefully determined by adding different concentrations of formic acid. High-resolution mass spectrometry and NMR spectroscopy were performed to verify the chemical properties of the compounds. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation of five compounds from leaves of Andrographis paniculata (Burm. f.) Nees by off-line two-dimensional high-speed counter-current chromatography combined with gradient and recycling elution.

PubMed

Zhang, Li; Liu, Qi; Yu, Jingang; Zeng, Hualiang; Jiang, Shujing; Chen, Xiaoqing

2015-05-01

An off-line two-dimensional high-speed counter-current chromatography method combined with gradient and recycling elution mode was established to isolate terpenoids and flavones from the leaves of Andrographis paniculata (Burm. f.) Nees. By using the solvent systems composed of n-hexane/ethyl acetate/methanol/water with different volume ratios, five compounds including roseooside, 5,4'-dihydroxyflavonoid-7-O-β-d-pyranglucuronatebutylester, 7,8-dimethoxy-2'-hydroxy-5-O-β-d-glucopyranosyloxyflavon, 14-deoxyandrographiside, and andrographolide were successfully isolated. Purities of these isolated compounds were all over 95% as determined by high-performance liquid chromatography. Their structures were identified by UV, mass spectrometry, and (1) H NMR spectroscopy. It has been demonstrated that the combination of off-line two-dimensional high-speed counter-current chromatography with different elution modes is an efficient technique to isolate compounds from complex natural product extracts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Online hyphenation of extraction, Sephadex LH-20 column chromatography, and high-speed countercurrent chromatography: A highly efficient strategy for the preparative separation of andrographolide from Andrographis paniculata in a single step.

PubMed

Zhang, Ying-Qi; Wang, Shan-Shan; Han, Chao; Xu, Jin-Fang; Luo, Jian-Guang; Kong, Ling-Yi

2017-12-01

A novel isolation strategy, online hyphenation of ultrasonic extraction, Sephadex LH-20 column chromatography combined with high-speed countercurrent chromatography, was developed for pure compounds extraction and purification. Andrographolide from Andrographis paniculata was achieved only in a single step purification protocol via the present strategy. The crude powder was ultrasonic extracted and extraction was pumped into Sephadex LH-20 column directly to cut the nontarget fractions followed by the second-dimensional high-speed countercurrent chromatography, hyphenated by a six-port valve equipped at the post-end of Sephadex LH-20 column, for the final purification. The results yielded andrographolide with the amount of 1.02 mg and a purity of 98.5% in a single step, indicating that the present method is effective to harvest target compound from medicinal plant. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A simple tool for tubing modification to improve spiral high-speed counter-current chromatography for protein purification

PubMed Central

Ito, Yoichiro; Ma, Xiaofeng; Clary, Robert

2016-01-01

A simple tool is introduced which can modify the shape of tubing to enhance the partition efficiency in high-speed countercurrent chromatography. It consists of a pair of interlocking identical gears, each coaxially holding a pressing wheel to intermittently compress plastic tubing in 0 – 10 mm length at every 1 cm interval. The performance of the processed tubing is examined in protein separation with 1.6 mm ID PTFE tubing intermittently pressed in 3 mm and 10 mm width both at 10 mm intervals at various flow rates and revolution speeds. A series of experiments was performed with a polymer phase system composed of polyethylene glycol and dibasic potassium phosphate each at 12.5% (w/w) in deionized water using three protein samples. Overall results clearly demonstrate that the compressed tubing can yield substantially higher peak resolution than the non-processed tubing. The simple tubing modifier is very useful for separation of proteins with high-speed countercurrent chromatography. PMID:27818942

Purification of α-glucosidase from mouse intestine by countercurrent chromatography coupled with a reverse micelle solvent system.

PubMed

He, Kai; Zou, Zongyao; Hu, Yinran; Yang, Yong; Xiao, Yubo; Gao, Pincao; Li, Xuegang; Ye, Xiaoli

2016-02-01

Countercurrent chromatography coupled with a reverse micelle solvent was applied to separate α-glucosidase, which is stable at pH 6.0-8.8, 15-50°C. The separation conditions are as follows: stationary phase: pH 4.0 Tris-HCl buffer phase containing 50 mM Tris-HCl and 50 mM KCl; mobile phase A: isooctane containing 50 mM anionic surfactant sodium di(2-ethylhexyl)sulfosuccinate; mobile phase B: 50 mM Tris-HCl buffer containing 500 mM KCl (pH 8.0); In total, 25 mL (23.9 mg) crude enzyme was injected through the injection valve, the enzymatic reaction and sodium dodecylsulfate polyacrylamide gel electrophoresis results imply that the activity of purified α-glucosidase is 6.63-fold higher than that of the crude enzyme. Therefore, countercurrent chromatography coupled with a reverse micelle solvent is capable for protein separation and enrichment. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A simple tool for tubing modification to improve spiral high-speed counter-current chromatography for protein purification.

PubMed

Ito, Yoichiro; Ma, Xiaofeng; Clary, Robert

2016-01-01

A simple tool is introduced which can modify the shape of tubing to enhance the partition efficiency in high-speed countercurrent chromatography. It consists of a pair of interlocking identical gears, each coaxially holding a pressing wheel to intermittently compress plastic tubing in 0 - 10 mm length at every 1 cm interval. The performance of the processed tubing is examined in protein separation with 1.6 mm ID PTFE tubing intermittently pressed in 3 mm and 10 mm width both at 10 mm intervals at various flow rates and revolution speeds. A series of experiments was performed with a polymer phase system composed of polyethylene glycol and dibasic potassium phosphate each at 12.5% (w/w) in deionized water using three protein samples. Overall results clearly demonstrate that the compressed tubing can yield substantially higher peak resolution than the non-processed tubing. The simple tubing modifier is very useful for separation of proteins with high-speed countercurrent chromatography.

Flow enhancement of deformable self-driven objects by countercurrent

NASA Astrophysics Data System (ADS)

Mashiko, Takashi; Fujiwara, Takashi

2016-10-01

We report numerical simulations of the mixed flows of two groups of deformable self-driven objects. The objects belonging to the group A (B) have drift coefficient D =DA (DB), where a positive (negative) value of D denotes the rightward (leftward) driving force. For co-current flows (DA ,DB > 0), the result is rather intuitive: the net flow of one group (QA) increases if the driving force of the other group is stronger than its own driving force (i.e., DB >DA), and decreases otherwise (DB

Separation of three phenolic high-molecular-weight compounds from the crude extract of Terminalia Chebula Retz. by ultrasound-assisted extraction and high-speed counter-current chromatography.

PubMed

Zou, Deng-lang; Chen, Tao; Li, Hong-mei; Chen, Chen; Zhao, Jing-yang; Li, Yu-lin

2016-04-01

This study presents an efficient strategy for separation of three phenolic compounds with high molecular weight from the crude extract of Terminalia chebula Retz. by ultrasound-assisted extraction and high-speed counter-current chromatography. The ultrasound-assisted extraction conditions were optimized by response surface methodology and the results showed the target compounds could be well enriched under the optimized extraction conditions. Then the crude extract was directly separated by high-speed counter-current chromatography without any pretreatment using n-hexane/ethyl acetate/methanol/water (1:7:0.5:3, v/v/v/v) as the solvent system. In 180 min, 13 mg of A, 18 mg of B, and 9 mg of C were obtained from 200 mg of crude sample. Their structures were identified as Chebulagic acid (A, 954 Da), Chebulinic acid (B, 956 Da), and Ellagic acid (C) by (1) H NMR spectroscopy. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparative enantioseparation of loxoprofen precursor by recycling countercurrent chromatography with hydroxypropyl-β-cyclodextrin as a chiral selector.

PubMed

Zhang, Hui; Qiu, Xujun; Lv, Liqiong; Sun, Wenyu; Wang, Chaoyue; Yan, Jizhong; Tong, Shengqiang

2018-04-17

Recycling countercurrent chromatography was successfully applied to the resolution of 2-(4-bromomethylphenyl)propionic acid, a key synthetic intermediate for synthesis of nonsteroidal anti-inflammatory drug loxoprofen, using hydroxypropyl-β-cyclodextrin as chiral selector. The two-phase solvent system composed of n-hexane/n-butyl acetate/0.1 mol/L citrate buffer solution with pH 2.4 (8:2:10, v/v/v) was selected. Influence factors for the enantioseparation were optimized, including type of substituted β-cyclodextrin, concentration of hydroxypropyl-β-cyclodextrin, separation temperature, and pH of aqueous phase. Under optimized separation conditions, 50 mg of 2-(4-bromomethylphenyl)propionic acid was enantioseparated using preparative recycling countercurrent chromatography. Technical details for recycling elution mode were discussed. The purities of both the S and R enantiomers were over 99.0% as determined by high-performance liquid chromatography. The enantiomeric excess of the S and R enantiomers reached 98.0%. The recovery of the enantiomers from eluted fractions was 40.8-65.6%, yielding 16.4 mg of the S enantiomer and 10.2 mg of the R enantiomer. At the same time, we attempted to enantioseparate the anti-inflammatory drug loxoprofen by countercurrent chromatography and high-performance liquid chromatography using a chiral mobile phase additive. However, no successful enantioseparation was achieved so far. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Schinus terebinthifolius scale-up countercurrent chromatography (Part I): High performance countercurrent chromatography fractionation of triterpene acids with off-line detection using atmospheric pressure chemical ionization mass spectrometry.

PubMed

Vieira, Mariana Neves; Costa, Fernanda das Neves; Leitão, Gilda Guimarães; Garrard, Ian; Hewitson, Peter; Ignatova, Svetlana; Winterhalter, Peter; Jerz, Gerold

2015-04-10

'Countercurrent chromatography' (CCC) is an ideal technique for the recovery, purification and isolation of bioactive natural products, due to the liquid nature of the stationary phase, process predictability and the possibility of scale-up from analytical to preparative scale. In this work, a method developed for the fractionation of Schinus terebinthifolius Raddi berries dichloromethane extract was thoroughly optimized to achieve maximal throughput with minimal solvent and time consumption per gram of processed crude extract, using analytical, semi-preparative and preparative 'high performance countercurrent chromatography' (HPCCC) instruments. The method using the biphasic solvent system composed of n-heptane-ethyl acetate-methanol-water (6:1:6:1, v/v/v/v) was volumetrically scaled up to increase sample throughput up to 120 times, while maintaining separation efficiency and time. As a fast and specific detection alternative, the fractions collected from the CCC-separations were injected to an 'atmospheric pressure chemical ionization mass-spectrometer' (APCI-MS/MS) and reconstituted molecular weight MS-chromatograms of the APCI-ionizable compounds from S. terebinthifolius were obtained. This procedure led to the direct isolation of tirucallane type triterpenes such as masticadienonic and 3β-masticadienolic acids. Also oleanonic and moronic acids have been identified for the first time in the species. In summary, this approach can be used for other CCC scale-up processes, enabling MS-target-guided isolation procedures. Copyright © 2015 Elsevier B.V. All rights reserved.

Cause and solution for false upstream boat velocities measured with a StreamPro acoustic doppler current profiler

USGS Publications Warehouse

Mueller, David S.; Rehmel, Mike S.; Wagner, Chad R.

2007-01-01

In 2003, Teledyne RD Instruments introduced the StreamPro acoustic Doppler current profiler which does not include an internal compass. During stationary moving-bed tests the StreamPro often tends to swim or kite from the end of the tether (the instrument rotates then moves laterally in the direction of the rotation). Because the StreamPro does not have an internal compass, it cannot account for the rotation. This rotation and lateral movement of the StreamPro on the end of the tether generates a false upstream velocity, which cannot be easily distinguished from a moving-bed bias velocity. A field test was completed to demonstrate that this rotation and lateral movement causes a false upstream boat velocity. The vector dot product of the boat velocity and the unit vector of the depth-averaged water velocity is shown to be an effective method to account for the effect of the rotation and lateral movement.

Phytoplankton community structure and nitrogen nutrition in Leeuwin Current and coastal waters off the Gascoyne region of Western Australia

NASA Astrophysics Data System (ADS)

Hanson, Christine E.; Waite, Anya M.; Thompson, Peter A.; Pattiaratchi, Charitha B.

2007-04-01

Within the coastal waters of the eastern Indian Ocean adjacent to Western Australia, we tested the hypothesis that regenerated production (and, by inference, the microbial food web) would predominate in oligotrophic Leeuwin Current (LC) and offshore (OS) surface waters. Conversely, we expected that new production would be more important within the ˜5 times more productive shelf countercurrents (Ningaloo and Capes Currents; NC&CC) and the LC&OS deep chlorophyll maximum (DCM). Phytoplankton species composition and abundance were assessed using both light microscopy and chemotaxonomic methods, and isotopic nitrogen uptake experiments ( 15NO 3-, 15NH 4+) were performed at trace (0.05 μM) and saturating (5.0 μM) levels. Phytoplankton community structure was statistically distinct between LC&OS and countercurrent regions. Picoplankton (unicellular cyanobacteria and prochlorophytes) accounted for a mean of 55-65% of pigment biomass in LC&OS waters, with haptophytes as the other primary contributor (21-32%). Conversely, within countercurrent and shelf regions, diatoms (up to 22%) and haptophytes (up to 57%) were more abundant, although cyanobacteria still played an important role (up to 40% of pigment biomass). Absolute NO 3- uptake rates for all samples ranged between 0.5 and 7.1 nmol L -1 h -1, and in countercurrent waters were not significantly different at the surface (3.0±2.1 nmol L -1 h -1; mean±SD) compared to the DCM (2.7±2.3 nmol L -1 h -1). However, in LC&OS waters, rates were significantly lower at the surface (1.2±0.7 nmol L -1 h -1) than the DCM (3.9±2.5 nmol L -1 h -1; p=0.05). These values represent conservative estimates for the region due to methodological difficulties encountered with nitrogen uptake experiments in these oligotrophic waters. In contrast with the distinct community composition between different water types, mean estimates of the f-ratio were similar across sampling depths and water types: 0.17±0.07 at the surface and 0.16±0.06 at the DCM of shelf countercurrent waters, and 0.14±0.05 at the surface and 0.14±0.09 at the DCM of LC&OS waters. These results demonstrate the importance of ammonium-based production in both oligotrophic LC&OS waters and the more productive upwelling-influenced countercurrents. They also highlight the utility of chemotaxonomic methods in studying pelagic ecosystem structure along the Gascoyne region of Western Australia.

Surface particle sizes on armoured gravel streambeds: Effects of supply and hydraulics

Treesearch

Peter J. Whiting; John G. King

2003-01-01

Most gravel-bed streams exhibit a surface armour in which the median grain size of the surface particles is coarser than that of the subsurface particles. This armour has been interpreted to result when the supply of sediment is less than the ability of the stream to move sediment. While there may be certain sizes in the bed for which the supply is less than the...

Perchlorate Found by Phoenix Could Provide a Mobile Brine Sludge at the Bed of Mars Northern Ice Cap that Would Allow Flow with Very Low Basal Temperatures: Possible Mechanism for Water Table Re-Charge

NASA Astrophysics Data System (ADS)

Fisher, D. A.; Hecht, M.; Kounaves, S.; Catling, D.

2009-03-01

The north cap of Mars has basal temperature that precludes the flow of ice. Phoenix discovered polar soils contain perchlorate salts. These salts depress the melting point so it could form a sludge that provides a mobile bed that moves the ice outwards.

Staged fluidized bed

DOEpatents

Mallon, Richard G.

1984-01-01

Method and apparatus 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.

Study on an advanced early rehabilitation training system for postural control using a tilting bed

NASA Astrophysics Data System (ADS)

Yu, Chang-Ho; Kim, Kyong; Kwon, Tae-Kyu; Hong, Chul-Un; Kim, Nam-Gyun

2005-12-01

It proposed a new early rehabilitation training system for postural control using a tilting bed, a visual display and a force plate. The conventional rehabilitation systems for postural control can't be applied to the patients lying in bed because the rehabilitation training using those systems is only possible when the patient can stand up by himself or herself. Moreover, there did not exist any device that could provide the sense of balance or the sensation of walking to the patients in bed. The software for the system consists of the training program and the analysis program. The training program was designed to improve the ability of postural control of the subjects by repeated training of moving the center of pressure (COP) applied to the forceplate. The training program consists of the COP maintaining training and the COP movement training in horizontal, vertical, 45° and -45° directions. The analysis program consists of the COP moving time analysis modules, the COP maintaining time analysis module. Through the experiments with real people, it verified the effectiveness of the new early rehabilitation training system. The results showe that this system is an effective system for early rehabilitation training and that our system might be useful as clinical equipment.

Rotary plant growth accelerating apparatus. [weightlessness

NASA Technical Reports Server (NTRS)

Dedolph, R. D. (Inventor)

1975-01-01

Rotary plant growth accelerating apparatus for increasing plant yields by effectively removing the growing plants from the constraints of gravity and increasing the plant yield per unit of space is described. The apparatus is comprised of cylindrical plant beds supported radially removed from a primary axis of rotation, with each plant bed being driven about its own secondary axis of rotation and simultaneously moved in a planetary path about the primary axis of rotation. Each plant bed is formed by an apertured outer cylinder, a perforated inner cylinder positioned coaxially, and rooting media disposed in the space between. A rotatable manifold distributes liquid nutrients and water to the rooting media through the perforations in the inner cylinders as the plant beds are continuously rotated by suitable drive means.

Idealized debris flow in flume with bed driven by a conveyor belt

USGS Publications Warehouse

Ling, Chi-Hai; Chen, Cheng-lung

1989-01-01

The generalized viscoplastic fluid (GVF) model is used to derive the theoretical expressions of two-dimensional velocities and surface profile for debris flow established in a flume with bed driven by a conveyor belt. The rheological parameters of the GVF model are evaluated through the comparison of theoretical results with measured data. A slip velocity of the established (steady) nonuniform flow on the moving bed (i.e., the conveyor belt) is observed, and a relation between the slip velocity and the velocity gradient at the bed is derived. Two belts, one rough and the other smooth, were tested. The flow profile in the flume is found to be linear and dependent on the roughness of the belt, but not much on its speed.

Freshwater mussel response to bedform movement: experimental stream studies

NASA Astrophysics Data System (ADS)

Kozarek, J. L.; MacGregor, K. R.; Hornbach, D.; Hove, M.

2017-12-01

Freshwater mussels are intrinsically linked to near-bed sediment dynamics, but it remains unclear how mussels respond to changing sediment loads across spatial and temporal scales. The interactions between mussels and sediment transport are complex and often involve feedback loops. Mussels are filter feeders removing suspended particles from the water column and the physical presence of mussels can have significant impacts on the structure of riverbed habitat. We investigated the feedbacks between mussels, flow, and migrating bedforms during flood experiments in the St. Anthony Falls Laboratory Outdoor StreamLab (OSL) at the University of Minnesota. The OSL is a field-scale sand-bed meandering stream channel with independent control over sediment feed (recirculated) and water flow (diverted from the Mississippi River). Mussel location, orientation to flow, and protrusion from sediment was surveyed immediately before, after, and one and two days after each flood event. Flow fields, bed shear stress, bedform migration, and bar topography were measured during each flooding event with and without mussels present (density = 4/m2 and 8/m2) to quantify the influence of mussels on channel morphology and bedform migration. Mobile bedforms (up to 14 cm high) were present for all flood events with quasi-equilibrium, aggrading, and degrading bed conditions. Mussels moved little horizontally during all flood events, but were shown to move quickly to deeper water after the flood receded. However, mussels moved vertically, burrowing or being buried under mobile bedforms, during each flood event. The research presented here will focus on feedbacks between three mussel species with different shell sculptures, flow conditions, and migrating bedforms during flooding events. These results reveal how freshwater mussels respond to and affect flow and sediment transport during flood events that are difficult to observe in the field.

Behavioral Responses of the Bed Bug to Permethrin-Impregnated ActiveGuard™ Fabric.

PubMed

Jones, Susan C; Bryant, Joshua L; Harrison, Scott A

2013-06-07

ActiveGuard™ Mattress Liners have been used to control house dust mites, and they also are commercially available as an integrated pest management tool for use against bed bugs (Cimex lectularius). The aim of our study was to evaluate responses of numerous populations of the bed bug to the permethrin-impregnated fabric, with particular regard to contact toxicity, repellency, and feeding inhibition. Continuous exposure to ActiveGuard fabric resulted in rapid intoxication for three of four populations, with 87 to 100% of moderately pyrethroid-resistant and susceptible bed bugs succumbing by 1 d. In comparison, a highly resistant population reached 22% mortality at 10 d. Video data revealed that bed bugs readily traversed ActiveGuard fabric and spent a considerable amount of time moving about and resting on it during a 12-h period. ActiveGuard fabric was non-repellent to bed bugs from five tested populations. Furthermore, significantly fewer bed bugs successfully fed to repletion through ActiveGuard fabric than through blank fabric for the five populations. With just 30 min of feeding exposure, mortality ranged from 4% to 83%, depending upon the bed bug strain. These laboratory studies indicate that ActiveGuard liners adversely affected bed bugs from diverse populations.

Investigation of Anaerobic Fluidized Bed Reactor/ Aerobic Moving Bed Bio Reactor (AFBR/MMBR) System for Treatment of Currant Wastewater

PubMed Central

JAFARI, Jalil; MESDAGHINIA, Alireza; NABIZADEH, Ramin; FARROKHI, Mehrdad; MAHVI, Amir Hossein

2013-01-01

Background: Anaerobic treatment methods are more suitable for the treatment of concentrated wastewater streams, offer lower operating costs, the production of usable biogas product. The aim of this study was to investigate the performance of an Anaerobic Fluidized Bed Reactor (AFBR)-Aerobic Moving Bed Bio Reactor (MBBR) in series arrangement to treat Currant wastewater. Methods: The bed materials of AFBR were cylindrical particles made of PVC with a diameter of 2–2.3 mm, particle density of 1250 kg/m3. The volume of all bed materials was 1.7 liter which expanded to 2.46 liters in fluidized situation. In MBBR, support media was composed of 1.5 liters Bee-Cell 2000 having porosity of 87% and specific surface area of 650m2/m3. Results: When system operated at 35 ºC, chemical oxygen demand (COD) removal efficiencies were achieved to 98% and 81.6% for organic loading rates (OLR) of 9.4 and 24.2 g COD/l.d, and hydraulic retention times (HRT) of 48 and 18 h, in average COD concentration feeding of 18.4 g/l, respectively. Conclusion: The contribution of AFBR in total COD removal efficiency at an organic loading rate (OLR) of 9.4 g COD/l.d was 95%, and gradually decreased to 76.5% in OLR of 24.2 g COD/l.d. Also with increasing in organic loading rate the contribution of aerobic reactor in removing COD gradually decreased. In this system, the anaerobic reactor played the most important role in the removal of COD, and the aerobic MBBR was actually needed to polish the anaerobic treated wastewater. PMID:26056640

Operation of an anaerobic filter compared with an anaerobic moving bed bioreactor for the treatment of waste water from hydrothermal carbonisation of fine mulch.

PubMed

Meier, J F; Austermann-Haun, U; Fettig, J; Liebe, H; Wichern, M

2017-10-01

This experimental study investigates the anaerobic digestion of waste water from hydrothermal carbonisation of fine mulch (wood chips) in combination with a co-substrate for the first time. Two anaerobic reactors, an anaerobic filter (AF) and an anaerobic moving bed bioreactor (AnMBBR), were operated over a period of 131 days at mesophilic conditions. The organic loading rate was increased to a maximum of 8.5 g L -l d -1 in the AF and the AnMBBR. Both reactors achieved similarly efficient chemical oxygen demand removal rates of 80% approximately (approx.) and high methane production rates of approx. 2.7 L L -1 d -1 . Nevertheless, signs of an inhibition were observed during the experiments.

Microbial shaping of sedimentary wrinkle structures

NASA Astrophysics Data System (ADS)

Mariotti, G.; Pruss, S. B.; Perron, J. T.; Bosak, T.

2014-10-01

Wrinkle structures on sandy bed surfaces were present in some of the earliest sedimentary environments, but are rare in modern environments. These enigmatic millimetre- to centimetre-scale ridges or pits are particularly common in sediments that harbour trace fossils and imprints of early animals, and appeared in the aftermath of some large mass extinctions. Wrinkle structures have been interpreted as possible remnants of microbial mats, but the formation mechanism and associated palaeoenvironmental and palaeoecological implications of these structures remain debated. Here we show that microbial aggregates can form wrinkle structures on a bed of bare sand in wave tank experiments. Waves with a small orbital amplitude at the bed surface do not move sand grains directly. However, they move millimetre-size, light microbial fragments and thereby produce linear sand ridges and rounded scour pits at the wavelengths observed in nature within hours. We conclude that wrinkle structures are morphological biosignatures that form at the sediment-water interface in wave-dominated environments, and not beneath microbial mats as previously thought. During early animal evolution, grazing by eukaryotic organisms may have temporarily increased the abundance of microbial fragments and thus the production of wrinkle structures.

Analysis of trickle-bed reactor for ethanol production from syngas using Clostridium ragsdalei

NASA Astrophysics Data System (ADS)

Devarapalli, Mamatha

The conversion of syngas components (CO, CO2 and H2) to liquid fuels such as ethanol involves complex biochemical reactions catalyzed by a group of acetogens such as Clostridium ljungdahlii, Clostridium carboxidivorans and Clostridium ragsdalei. The low ethanol productivity in this process is associated with the low solubility of gaseous substrates CO and H2 in the fermentation medium. In the present study, a 1-L trickle-bed reactor (TBR) was analyzed to understand its capabilities to improve the mass transfer of syngas in fermentation medium. Further, semi-continuous and continuous syngas fermentations were performed using C. ragsdalei to evaluate the ability of the TBR for ethanol production. In the mass transfer studies, using 6-mm glass beads, it was found that the overall mass transfer coefficient (kLa/V L) increased with the increase in gas flow rate from 5.5 to 130.5 sccm. Further, an increase in the liquid flow rate in the TBR decreased the kLa/VL due to the increase in liquid hold up volume (VL) in the packing. The highest kLa/VL values of 421 h-1 and 178 h-1 were achieved at a gas flow rate of 130.5 sccm for 6-mm and 3-mm glass beads, respectively. Semi-continuous fermentations were performed with repetitive medium replacement in counter-current and co-current modes. In semi-continuous fermentations with syngas consisting of 38% CO, 5% N2, 28.5% CO2 and 28.5% H2 (by volume), the increase in H2 conversion (from 18 to 55%) and uptake (from 0.7 to 2.2 mmol/h) were observed. This increase was attributed to more cell attachment in the packing that reduced CO inhibition to hydrogenase along the column length and increased the H2 uptake. The maximum ethanol produced during counter-current and co-current modes were 3.0 g/L and 5.7 g/L, respectively. In continuous syngas fermentation, the TBR was operated at dilution rates between 0.006 h-1and 0.012 h -1 and gas flow rates between 1.5 sccm and 18.9 sccm. The highest ethanol concentration of 13 g/L was achieved at dilution and gas flow rates of 0.012 h-1 and 18.9 sccm, respectively. The molar ratio of ethanol to acetic acid of 4:1 was obtained during continuous fermentation which was 7.7 times higher than in semi-continuous fermentations. The improvement of the reactor performance in continuous mode gives scope to explore the TBR as a potential bioreactor design for large scale biofuels production.

Smoldering of porous media: numerical model and comparison of calculations with experiment

NASA Astrophysics Data System (ADS)

Lutsenko, N. A.; Levin, V. A.

2017-10-01

Numerical modelling of smoldering in porous media under natural convection is considered. Smoldering can be defined as a flameless exothermic surface reaction; it is a type of heterogeneous combustion which can propagate in porous media. Peatbogs, landfills and other natural or man-made porous objects can sustain smoldering under natural (or free) convection, when the flow rate of gas passed through the porous object is unknown a priori. In the present work a numerical model is proposed for investigating smoldering in porous media under natural convection. The model is based on the assumption of interacting interpenetrating continua using classical approaches of the theory of filtration combustion and includes equations of state, continuity, momentum conservation and energy for solid and gas phases. Computational results obtained by means of the numerical model in one-dimensional case are compared with the experimental data of the smoldering combustion in polyurethane foam under free convection in the gravity field, which were described in literature. Calculations shows that when simulating both co-current combustion (when the smoldering wave moves upward) and counter-current combustion (when the smoldering wave moves downward), the numerical model can provide a good quantitative agreement with experiment if the parameters of the model are well defined.

Bed bug aggregation on dirty laundry: a mechanism for passive dispersal.

PubMed

Hentley, William T; Webster, Ben; Evison, Sophie E F; Siva-Jothy, Michael T

2017-09-28

Bed bugs have shown a recent and rapid global expansion that has been suggested to be caused by cheap air travel. How a small, flightless and anachoretic insect that hides within its host's sleeping area manages to travel long distances is not yet clear. Bed bugs are attracted to the odour of sleeping humans and we suggest that soiled clothing may present a similarly attractive cue, allowing bed bugs to 'hitch-hike' around the world after aggregating in the laundry bags of travellers. We show that (1) soiled clothing is significantly more attractive than clean clothing to active bed bugs moving within a bedroom sized arena and (2) elevation of CO 2 to a level that simulates human occupancy in the same arena appears to initiate search behaviour rather than direct it. Our results show, for the first time, how leaving worn clothing exposed in sleeping areas when travelling can be exploited by bed bugs to facilitate passive dispersal.

Effect of a powered drive on pushing and pulling forces when transporting bariatric hospital beds.

PubMed

Wiggermann, Neal

2017-01-01

Powered drives designed to assist with moving hospital beds are commercially available but no studies have evaluated whether they reduce the push and pull forces likely contributing to injury in caregivers. This study measured hand forces of 10 caregivers maneuvering a manual and powered bariatric bed through simulated hospital environments (hallway, elevator, and ramp). Peak push and pull forces exceeded previously established psychophysical limits for all activities with the manual bed. For the powered bed, peak forces were significantly (p < 0.05) lower for all tasks, and below psychophysical limits. Powered drive reduced peak forces between 38% (maneuvering into elevator) and 94% (descending ramp). Powered drive also reduced stopping distance by 55%. When maneuvering, the integral of hand force was 34% lower with powered drive, but average forces during straight-line pushing did not differ between beds. Powered drive may reduce the risk of injury or the number of caregivers needed for transport. Copyright © 2016 Elsevier Ltd. All rights reserved.

Method and apparatus for improving heat transfer in a fluidized bed

DOEpatents

Lessor, Delbert L.; Robertus, Robert J.

1990-01-01

An apparatus contains a fluidized bed that includes particles of different triboelectrical types, each particle type acquiring an opposite polarity upon contact. The contact may occur between particles of the two types or between particles of etiher type and structure or fluid present in the apparatus. A fluidizing gas flow is passed through the particles to produce the fluidized bed. Immersed within the bed are electrodes. An alternating EMF source connected to the electrodes applies an alternating electric field across the fluidized bed to cause particles of the first type to move relative to particles of the second type and relative to the gas flow. In a heat exchanger incorporating the apparatus, the electrodes are conduits conveying a fluid to be heated. The two particle types alternately contact each conduit to transfer heat from a hot gas flow to the second fluid within the conduit.

Improving efficiency, reducing infection, and enhancing experience.

PubMed

Massa, Judith

For health professionals to make an informed choice and tailor each bed bath to the individual needs of the patient, they must firstly understand the different bed bath options available, their impact on skin integrity, and any associated risks they may pose to the patient in terms of cross-infection. Only with this knowledge can health professionals determine the appropriate form and frequency of the bed bath. Specialist wipes offer significant improvements in skin care and a reduced risk of cross-infection, compared with the traditional soap and water bed bath. Use of these wipes also improves the efficiency of the process, which links to the Productive Ward Initiative and results in clinical staff (i.e. nursing staff, healthcare assistants) having more time available to undertake additional patient care activities. This product focus highlights the benefits of moving to a wipe-based bed bath method, and the significant efficiency savings that can be realized as a result.

Effect of long-term hypokinesia on the electrolytic composition of the blood in patients with osteoarticular tuberculosis

NASA Technical Reports Server (NTRS)

Zakutaeva, V. P.

1980-01-01

Seventy-six patients with osteoarticular tuberculosis were divided into two groups, one of which was required to maintain strict bed rest and the other of which was allowed unrestricted motor activity. A study of blood electrolyte composition in the two groups revealed that bed rest for these patients results in decreased plasma potassium calcium, and magnesium content, but that these indices improved after the patients were allowed to move freely. The study suggests that patients with osteoarticular tuberculosis who are on bed rest be carefully observed for alterations in blood electrolytes and that proper electrolyte balance be maintained.

Counter-current acid leaching process for the removal of Cu, Pb, Sb and Zn from shooting range soil.

PubMed

Lafond, Stéphanie; Blais, Jean-François; Mercier, Guy; Martel, Richard

2013-01-01

This research explores the performance of a counter-current leaching process (CCLP) for Cu, Pb, Sb and Zn extraction in a polluted shooting range soil. The initial metal concentrations in the soil were 1790 mg Cu/kg, 48,300 mg Pb/kg, 840 mg Sb/kg and 368 mg Zn/kg. The leaching process consisted of five one-hour acid leaching steps, which used 1 M H2SO4 + 4 M NaCl (20 degrees C, soil suspension = 100 g/L) followed by two water rinsing steps. Ten counter-current remediation cycles were completed and the average metal removal yields were 98.3 +/- 0.3% of Cu, 99.5 +/- 0.1% of Pb, 75.5 +/- 5.1% of Sb and 29.1 +/- 27.2% of Zn. The quality of metal leaching did not deteriorate throughout the 10 remediation cycles completed for this study. The CCLP reduced acid and salt use by approximately 68% and reduced water consumption by approximately 60%, exceeding reductions achieved by a standard acid leaching process.

Counter-current thermocapillary migration of bubbles in self-rewetting liquids

NASA Astrophysics Data System (ADS)

Nazareth, R.; Saenz, P.; Sefiane, K.; Kim, J.; Valluri, P.

2016-11-01

In this work, we study the counter-current thermocapillary propulsion of a suspended bubble in the fluid flowing inside a channel subject to an axial temperature gradient when the surface tension dependence on temperature is non-monotonic. We use direct numerical simulations to address the two-phase conservation of mass, momentum and energy with a volume-of-fluid method to resolve the deformable interface. Two distinct regimes of counter-current bubble migration are characterized: i) "exponential decay" where the bubble decelerates rapidly until it comes to a halt at the spatial position corresponding to the minimum surface tension and ii) "sustained oscillations" where the bubble oscillates about the point of minimum surface tension. We illustrate how these sustained oscillations arise at low capillary number O(10-5) and moderate Reynolds number O(10) and, they are dampened by viscosity at lower Reynolds number. These results are in agreement with the experiments by Shanahan and Sefiane (Sci. Rep. 4, 2014). The work was supported by the Science without Borders program from CAPES agency of Brazilian Ministry of Education and the European Commission's Thermapower Project (294905).

Schinus terebinthifolius countercurrent chromatography (Part III): Method transfer from small countercurrent chromatography column to preparative centrifugal partition chromatography ones as a part of method development.

PubMed

das Neves Costa, Fernanda; Hubert, Jane; Borie, Nicolas; Kotland, Alexis; Hewitson, Peter; Ignatova, Svetlana; Renault, Jean-Hugues

2017-03-03

Countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC) are support free liquid-liquid chromatography techniques sharing the same basic principles and features. Method transfer has previously been demonstrated for both techniques but never from one to another. This study aimed to show such a feasibility using fractionation of Schinus terebinthifolius berries dichloromethane extract as a case study. Heptane - ethyl acetate - methanol -water (6:1:6:1, v/v/v/v) was used as solvent system with masticadienonic and 3β-masticadienolic acids as target compounds. The optimized separation methodology previously described in Part I and II, was scaled up from an analytical hydrodynamic CCC column (17.4mL) to preparative hydrostatic CPC instruments (250mL and 303mL) as a part of method development. Flow-rate and sample loading were further optimized on CPC. Mobile phase linear velocity is suggested as a transfer invariant parameter if the CPC column contains sufficient number of partition cells. Copyright © 2017 Elsevier B.V. All rights reserved.

Purification of semiconducting single-walled carbon nanotubes by spiral counter-current chromatography.

PubMed

Knight, Martha; Lazo-Portugal, Rodrigo; Ahn, Saeyoung Nate; Stefansson, Steingrimur

2017-02-03

Over the last decade man-made carbon nanostructures have shown great promise in electronic applications, but they are produced as very heterogeneous mixtures with different properties so the achievement of a significant commercial application has been elusive. The dimensions of single-wall carbon nanotubes are generally a nanometer wide, up to hundreds of microns long and the carbon nanotubes have anisotropic structures. They are processed to have shorter lengths but they need to be sorted by diameter and chirality. Thus counter-current chromatography methods developed for large molecules are applied to separate these compounds. A modified mixer-settler spiral CCC rotor made with 3 D printed disks was used with a polyethylene glycol-dextran 2-phase solvent system and a surfactant gradient to purify the major species in a commercial preparation. We isolated the semi-conducting single walled carbon nanotube chiral species identified by UV spectral analysis. The further development of spiral counter-current chromatography instrumentation and methods will enable the scalable purification of carbon nanotubes useful for the next generation electronics. Copyright © 2016 Elsevier B.V. All rights reserved.

Isolation and purification of arctigenin from Fructus Arctii by enzymatic hydrolysis combined with high-speed counter-current chromatography.

PubMed

Liu, Feng; Xi, Xingjun; Wang, Mei; Fan, Li; Geng, Yanling; Wang, Xiao

2014-02-01

Enzymatic hydrolysis pretreatment combined with high-speed counter-current chromatography for the transformation and isolation of arctigenin from Fructus Arctii was successfully developed. In the first step, the extract solution of Fructus Arctii was enzymatic hydrolyzed by β-glucosidase. The optimal hydrolysis conditions were 40°C, pH 5.0, 24 h of hydrolysis time, and 1.25 mg/mL β-glucosidase concentration. Under these conditions, the content of arctigenin was transformed from 2.60 to 12.59 mg/g. In the second step, arctigenin in the hydrolysis products was separated and purified by high-speed counter-current chromatography with a two-phase solvent system composed of petroleum ether/ethyl acetate/methanol/water (10:25:15:20, v/v), and the fraction was analyzed by HPLC, ESI-MS, and (1)H NMR spectroscopy. Finally, 102 mg of arctigenin with a purity of 98.9% was obtained in a one-step separation from 200 mg of hydrolyzed sample. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Aches and pains during pregnancy

MedlinePlus

... between 18 and 24 weeks. When you feel stretching or pain, move slowly or change positions. Mild ... common in the last months of pregnancy. Sometimes stretching your legs before bed will reduce the cramps. ...

Perched Ground Water in Zeolitized-Bedded Tuff, Rainier Mesa and Vicinity, Nevada Test Site, Nevada

USGS Publications Warehouse

Thordarson, William

1965-01-01

Rainier Mesa--site of the first series of underground nuclear detonations--is the highest of a group of ridges and mesas within the Nevada Test Site. The mesa is about 9.5 square miles in area and reaches a maximum altitude of 7,679 feet. The mesa is underlain by welded tuff, friable-bedded tuff, and zeolitized-bedded tuff of the Piapi Canyon Group and the Indian Trail Formation of Tertiary age. The tuff--2,000 to 9,000 feet thick--rests unconformably upon thrust-faulted miogeosynclinal rocks of Paleozoic age. Zeolitic-bedded tuff at the base of the tuff sequence controls the recharge rate of ground water to the underlying and more permeable Paleozoic aquifers. The zeolitic tuff--600 to 800 feet thick--is a fractured aquitard with high interstitial porosity, but with very low interstitial permeability and fracture transmissibility. The interstitial porosity ranges from 29 to 38 percent, the interstitial permeability is generally less than 0.009 gpd/ft3, and the fracture transmissibility ranges from 10 to 100 gpd/ft for 900 feet of saturated rock. The tuff is generally fully saturated interstitially hundreds of feet above the regional water table, yet no appreciable volume of water moves through the interstices because of the very low permeability. The only freely moving water observed in miles of underground workings occurred in fractures, usually fault zones.

Ionic Liquid-Liquid Chromatography: A New General Purpose Separation Methodology.

PubMed

Brown, Leslie; Earle, Martyn J; Gîlea, Manuela A; Plechkova, Natalia V; Seddon, Kenneth R

2017-08-10

Ionic liquids can form biphasic solvent systems with many organic solvents and water, and these solvent systems can be used in liquid-liquid separations and countercurrent chromatography. The wide range of ionic liquids that can by synthesised, with specifically tailored properties, represents a new philosophy for the separation of organic, inorganic and bio-based materials. A customised countercurrent chromatograph has been designed and constructed specifically to allow the more viscous character of ionic liquid-based solvent systems to be used in a wide variety of separations (including transition metal salts, arenes, alkenes, alkanes, bio-oils and sugars).

Behavioral Responses of the Bed Bug to Permethrin-Impregnated ActiveGuard™ Fabric

PubMed Central

Jones, Susan C.; Bryant, Joshua L.; Harrison, Scott A.

2013-01-01

ActiveGuard™ Mattress Liners have been used to control house dust mites, and they also are commercially available as an integrated pest management tool for use against bed bugs (Cimex lectularius). The aim of our study was to evaluate responses of numerous populations of the bed bug to the permethrin-impregnated fabric, with particular regard to contact toxicity, repellency, and feeding inhibition. Continuous exposure to ActiveGuard fabric resulted in rapid intoxication for three of four populations, with 87 to 100% of moderately pyrethroid-resistant and susceptible bed bugs succumbing by 1 d. In comparison, a highly resistant population reached 22% mortality at 10 d. Video data revealed that bed bugs readily traversed ActiveGuard fabric and spent a considerable amount of time moving about and resting on it during a 12-h period. ActiveGuard fabric was non-repellent to bed bugs from five tested populations. Furthermore, significantly fewer bed bugs successfully fed to repletion through ActiveGuard fabric than through blank fabric for the five populations. With just 30 min of feeding exposure, mortality ranged from 4% to 83%, depending upon the bed bug strain. These laboratory studies indicate that ActiveGuard liners adversely affected bed bugs from diverse populations. PMID:26464388

Flow regions of granules in Dorfan Impingo filter for gas cleanup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuo, J.T.; Smid, J.; Hsiau, S.S.

1999-07-01

Inside a two-dimensional model of the louvered Dorfan Impingo panel with transparent front and rear walls the flow region of filter granules without gas cross flow were observed. The white PE beads were used as filter granules. Colored PE beads served as tracers. Filter granules were discharged and circulated to the bed. The flow rate of filter medium was controlled by the belt conveyor. The image processing system including a Frame Grabber and JVC videocamera was used to record the granular flow. Every image of motion was digitized and stored in a file. The flow patterns and the quasi-stagnant zonesmore » history in the moving granular bed were evaluated. The experiment showed fast central moving region (flowing core) of filter granules and quasi-stagnant zones close to louver walls.« less

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

2013-12-06

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. Copyright © 2013 Elsevier B.V. All rights reserved.

Trends in infant bedding use: National Infant Sleep Position study, 1993-2010.

PubMed

Shapiro-Mendoza, Carrie K; Colson, Eve R; Willinger, Marian; Rybin, Denis V; Camperlengo, Lena; Corwin, Michael J

2015-01-01

Use of potentially hazardous bedding, as defined by the American Academy of Pediatrics (eg, pillows, quilts, comforters, loose bedding), is a modifiable risk factor for sudden infant death syndrome and unintentional sleep-related suffocation. The proportion of US infants sleeping with these types of bedding is unknown. To investigate the US prevalence of and trends in bedding use, we analyzed 1993-2010 data from the National Infant Sleep Position study. Infants reported as being usually placed to sleep with blankets, quilts, pillows, and other similar materials under or covering them in the last 2 weeks were classified as bedding users. Logistic regression was used to describe characteristics associated with bedding use. From 1993 to 2010, bedding use declined but remained a widespread practice (moving average of 85.9% in 1993-1995 to 54.7% in 2008-2010). Prevalence was highest for infants of teen-aged mothers (83.5%) and lowest for infants born at term (55.6%). Bedding use was also frequently reported among infants sleeping in adult beds, on their sides, and on a shared surface. The rate of decline in bedding use was markedly less from 2001-2010 compared with 1993-2000. For 2007 to 2010, the strongest predictors (adjusted odds ratio: ≥1.5) of bedding use were young maternal age, non-white race and ethnicity, and not being college educated. Bedding use for infant sleep remains common despite recommendations against this practice. Understanding trends in bedding use is important for tailoring safe sleep interventions. Copyright © 2015 by the American Academy of Pediatrics.

Trends in Infant Bedding Use: National Infant Sleep Position Study, 1993–2010

PubMed Central

Colson, Eve R.; Willinger, Marian; Rybin, Denis V.; Camperlengo, Lena; Corwin, Michael J.

2015-01-01

BACKGROUND: Use of potentially hazardous bedding, as defined by the American Academy of Pediatrics (eg, pillows, quilts, comforters, loose bedding), is a modifiable risk factor for sudden infant death syndrome and unintentional sleep-related suffocation. The proportion of US infants sleeping with these types of bedding is unknown. METHODS: To investigate the US prevalence of and trends in bedding use, we analyzed 1993–2010 data from the National Infant Sleep Position study. Infants reported as being usually placed to sleep with blankets, quilts, pillows, and other similar materials under or covering them in the last 2 weeks were classified as bedding users. Logistic regression was used to describe characteristics associated with bedding use. RESULTS: From 1993 to 2010, bedding use declined but remained a widespread practice (moving average of 85.9% in 1993–1995 to 54.7% in 2008–2010). Prevalence was highest for infants of teen-aged mothers (83.5%) and lowest for infants born at term (55.6%). Bedding use was also frequently reported among infants sleeping in adult beds, on their sides, and on a shared surface. The rate of decline in bedding use was markedly less from 2001–2010 compared with 1993–2000. For 2007 to 2010, the strongest predictors (adjusted odds ratio: ≥1.5) of bedding use were young maternal age, non-white race and ethnicity, and not being college educated. CONCLUSIONS: Bedding use for infant sleep remains common despite recommendations against this practice. Understanding trends in bedding use is important for tailoring safe sleep interventions. PMID:25452654

Qualitative and quantitative evaluation of solvent systems for countercurrent separation.

PubMed

Friesen, J Brent; Ahmed, Sana; Pauli, Guido F

2015-01-16

Rational solvent system selection for countercurrent chromatography and centrifugal partition chromatography technology (collectively known as countercurrent separation) studies continues to be a scientific challenge as the fundamental questions of comparing polarity range and selectivity within a solvent system family and between putative orthogonal solvent systems remain unanswered. The current emphasis on metabolomic investigations and analysis of complex mixtures necessitates the use of successive orthogonal countercurrent separation (CS) steps as part of complex fractionation protocols. Addressing the broad range of metabolite polarities demands development of new CS solvent systems with appropriate composition, polarity (π), selectivity (σ), and suitability. In this study, a mixture of twenty commercially available natural products, called the GUESSmix, was utilized to evaluate both solvent system polarity and selectively characteristics. Comparisons of GUESSmix analyte partition coefficient (K) values give rise to a measure of solvent system polarity range called the GUESSmix polarity index (GUPI). Solvatochromic dye and electrical permittivity measurements were also evaluated in quantitatively assessing solvent system polarity. The relative selectivity of solvent systems were evaluated with the GUESSmix by calculating the pairwise resolution (αip), the number of analytes found in the sweet spot (Nsw), and the pairwise resolution of those sweet spot analytes (αsw). The combination of these parameters allowed for both intra- and inter-family comparison of solvent system selectivity. Finally, 2-dimensional reciprocal shifted symmetry plots (ReSS(2)) were created to visually compare both the polarities and selectivities of solvent system pairs. This study helps to pave the way to the development of new solvent systems that are amenable to successive orthogonal CS protocols employed in metabolomic studies. Copyright © 2014 Elsevier B.V. All rights reserved.

Dynamic pH junction high-speed counter-current chromatography coupled with microwave-assisted extraction for online separation and purification of alkaloids from Stephania cepharantha.

PubMed

Yuan, Zhiquan; Xiao, Xiaohua; Li, Gongke

2013-11-22

A simple and efficient dynamic pH junction high-speed counter-current chromatography method was developed and further applied to the online extraction, separation and purification of alkaloids from Stephania cepharantha by coupling with microwave-assisted extraction. Mineral acid and organic base were added into the mobile phase and the sample solution, respectively, leading to the formation of a dynamic pH junction in the column and causing focus of alkaloids. Selective focus of analytes can be achieved on the basis of velocity changes of the pH junction through appropriate selection of solvent systems and optimization of additive concentrations. The extract can be directly introduced into the HSCCC for the online extraction, separation and purification of alkaloids from S. cepharantha. Continuous separation can be easily achieved with the same solvent system. Under the optimum conditions, 6.0 g original sample was extracted with 60 mL of the upper phase of hexane-ethyl acetate-methanol-water (1:1:1:1, v/v/v/v) containing 10% triethylamine under 50 °C and 400 W irradiation power for 10 min, the extracts were directly separated and purified by high-speed counter-current chromatography. A total of 5.7 mg sinomenine, 8.3mg 6,7-di-O-acetylsinococuline, 17.9 mg berbamine, 12.7 mg isotetrandrine and 14.6 mg cepharanthine were obtained with purities of 96.7%, 93.7%, 98.7%, 97.3% and 99.3%, respectively. The online method provides good selectivity to ionizable compounds and improves the separation and purification efficiency of the high-speed counter-current chromatography technique. It has good potential for separation and purification of effective compounds from natural products. Copyright © 2013 Elsevier B.V. All rights reserved.

48 CFR 52.247-13 - Accessorial Services-Moving Contracts.

Code of Federal Regulations, 2011 CFR

2011-10-01

... of property; e.g., beds and sectional bookcases, and the preparing of appliances; e.g., washers... uncrating and placement of property. The Contractor shall unpack and/or uncrate all property that was packed...

48 CFR 52.247-13 - Accessorial Services-Moving Contracts.

Code of Federal Regulations, 2010 CFR

2010-10-01

... of property; e.g., beds and sectional bookcases, and the preparing of appliances; e.g., washers... uncrating and placement of property. The Contractor shall unpack and/or uncrate all property that was packed...

9. Historic American Buildings Survey Josiah T. Tubby, Photographer September ...

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

9. Historic American Buildings Survey Josiah T. Tubby, Photographer September 1936 SOUTHWEST WALL EAST BED ROOM - Jefferds Tavern, Harraseekit Road (moved to U.S. Route 1A, York), Wells, York County, ME

10. Historic American Buildings Survey Josiah T. Tubby, Photographer September ...

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

10. Historic American Buildings Survey Josiah T. Tubby, Photographer September 1936 DETAIL OF MANTEL (east bed room) - Jefferds Tavern, Harraseekit Road (moved to U.S. Route 1A, York), Wells, York County, ME

Moving a patient from bed to a wheelchair

MedlinePlus

... the patient into the seat. At the same time, ask the patient to reach for the wheelchair armrest. If the patient starts to fall during the transfer, lower the person to the nearest flat surface, ...

A patient transfer apparatus between bed and stretcher.

PubMed

Wang, Hongbo; Kasagami, Fumio

2008-02-01

This paper presents a patient transfer apparatus between bed and stretcher. This apparatus makes it possible for the nurse to move weak, injured, or paralyzed patient from bed to stretcher, or vice versa, alone. Moreover, the suffering, stress, and uneasy feeling of the patient can be alleviated. This paper describes the specification, mechanical design, control system, and motion control of the apparatus. A special devised mechanism is developed, and a new servo system is used in this control system. The control principle and algorithm of the new servo system are proposed, and the motion-control method and safety function of the apparatus are described. The experimental results and evaluation indicated the effectiveness of this system.

Bed Surface Adjustments to Spatially Variable Flow in Low Relative Submergence Regimes

NASA Astrophysics Data System (ADS)

Monsalve, A.; Yager, E. M.

2017-11-01

In mountainous rivers, large relatively immobile grains partly control the local and reach-averaged flow hydraulics and sediment fluxes. When the flow depth is similar to the size of these grains (low relative submergence), heterogeneous flow structures and plunging flow cause spatial distributions of bed surface elevations, textures, and sedimentation rates. To explore how the bed surface responds to these flow variations we conducted a set of experiments in which we varied the relative submergence of staggered hemispheres (simulated large boulders) between runs. All experiments had the same average sediment transport capacity, upstream sediment supply, and initial bed thickness and grain size distribution. We combined our laboratory measurements with a 3-D flow model to obtain the detailed flow structure around the hemispheres. The local bed shear stress field displayed substantial variability and controlled the bed load transport rates and direction in which sediment moved. The divergence in bed shear stress caused by the hemispheres promoted size-selective bed load deposition, which formed patches of coarse sediment upstream of the hemisphere. Sediment deposition caused a decrease in local bed shear stress, which combined with the coarser grain size, enhanced the stability of this patch. The region downstream of the hemispheres was largely controlled by a recirculation zone and had little to no change in grain size, bed elevation, and bed shear stress. The formation, development, and stability of sediment patches in mountain streams is controlled by the bed shear stress divergence and magnitude and direction of the local bed shear stress field.

Effect of filter media size, mass flow rate and filtration stage number in a moving-bed granular filter on the yield and properties of bio-oil from fast pyrolysis of biomass.

PubMed

Paenpong, Chaturong; Inthidech, Sudsakorn; Pattiya, Adisak

2013-07-01

Fast pyrolysis of cassava rhizome was performed in a bench-scale fluidised-bed reactor unit incorporated with a cross-flow moving-bed granular filter. The objective of this research was to examine several process parameters including the granular size (425-1160 μm) and mass flow rate (0-12 g/min) as well as the number of the filtration stages (1-2 stages) on yields and properties of bio-oil. The results showed that the bio-oil yield decreased from 57.7 wt.% to 42.0-49.2 wt.% when increasing the filter media size, the mass flow rate and the filtration stage number. The effect of the process parameters on various properties of bio-oil is thoroughly discussed. In general, the bio-oil quality in terms of the solids content, ash content, initial viscosity, viscosity change and ageing rate could be enhanced by the hot vapour granular filtration. Therefore, bio-oil of high stability could be produced by the pyrolysis reactor configuration designed in this work. Copyright © 2013 Elsevier Ltd. All rights reserved.

Treatment of mountain refuge wastewater by fixed and moving bed biofilm systems.

PubMed

Andreottola, G; Damiani, E; Foladori, P; Nardelli, P; Ragazzi, M

2003-01-01

Tourists visiting mountain refuges in the Alps have increased significantly in the last decade and the number of refuges and huts at high altitude too. In this research the results of an intensive monitoring of a wastewater treatment plant (WWTP) for a tourist mountain refuge located at 2,981 m a.s.l. are described. Two biofilm reactors were adopted: (a) a Moving Bed Biofilm Reactor (MBBR); (b) a submerged Fixed Bed Biofilm Reactor (FBBR). The aims of this research were: (i) the evaluation of the main parameters characterising the processes and involved in the design of the wastewater plants, in order to compare advantages and disadvantages of the two tested alternatives; (ii) the acquisition of an adequate knowledge of the problems connected with the wastewater treatment in alpine refuges. The main results have been: (i) a quick start-up of the biological reactors obtainable thanks to a pre-colonization before the transportation of the plastic carriers to the refuge at the beginning of the tourist season; (ii) low volume and area requirement; (iii) significantly higher removal efficiency compared to other fixed biomass systems, such as trickling filters, but the energy consumption is higher.

Convection in deep vertically shaken particle beds. III. Convection mechanisms

NASA Astrophysics Data System (ADS)

Klongboonjit, Sakon; Campbell, Charles S.

2008-10-01

Convection in a deep vertically vibrated two-dimensional cell of granular material occurs in the form of counter-rotating cells that move material from the walls to the center of the channel and back again. At least for deep beds, where for much of the cycle, particles are in long duration contact with their neighbors, convection only appears for a short potion of every third vibrational period. That period is delimited by the interaction of three types of internal waves, a compression wave, and two types of expansion waves. Four mechanisms are identified that drive the four basic motions of convection: (1) particles move upward at the center as the result of compression wave, (2) downward at the wall as a combined effect of frictional holdback by the walls and the downward pull of gravity, (3) from the center to the walls along the free surface due to the heaping of the bed generated by the compression wave, and (4) toward the center in the interior of the box to form the bottom of convection rolls due to the relaxation of compressive stresses caused by an expansion wave. Convection only occurs when the conditions are right for all four mechanisms to be active simultaneously.

Management of turbidity current venting in reservoirs under different bed slopes.

PubMed

Chamoun, Sabine; De Cesare, Giovanni; Schleiss, Anton J

2017-12-15

The lifetime and efficiency of dams is endangered by the process of sedimentation. To ensure the sustainable use of reservoirs, many sediment management techniques exist, among which venting of turbidity currents. Nevertheless, a number of practical questions remain unanswered due to a lack of systematic investigations. The present research introduces venting and evaluates its performance using an experimental model. In the latter, turbidity currents travel on a smooth bed towards the dam and venting is applied through a rectangular bottom outlet. The combined effect of outflow discharge and bed slopes on the sediment release efficiency of venting is studied based on different criteria. Several outflow discharges are tested using three different bed slopes (i.e., 0%, 2.4% and 5.0%). Steeper slopes yield higher venting efficiency. Additionally, the optimal outflow discharge leading to the largest venting efficiency with the lowest water loss increases when moving from the horizontal bed to the inclined positions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spiral Countercurrent Chromatography

PubMed Central

Ito, Yoichiro; Knight, Martha; Finn, Thomas M.

2013-01-01

For many years, high-speed countercurrent chromatography conducted in open tubing coils has been widely used for the separation of natural and synthetic compounds. In this method, the retention of the stationary phase is solely provided by the Archimedean screw effect by rotating the coiled column in the centrifugal force field. However, the system fails to retain enough of the stationary phase for polar solvent systems such as the aqueous–aqueous polymer phase systems. To address this problem, the geometry of the coiled channel was modified to a spiral configuration so that the system could utilize the radially acting centrifugal force. This successfully improved the retention of the stationary phase. Two different types of spiral columns were fabricated: the spiral disk assembly, made by stacking multiple plastic disks with single or four interwoven spiral channels connected in series, and the spiral tube assembly, made by inserting the tetrafluoroethylene tubing into a spiral frame (spiral tube support). The capabilities of these column assemblies were successfully demonstrated by separations of peptides and proteins with polar two-phase solvent systems whose stationary phases had not been well retained in the earlier multilayer coil separation column for high-speed countercurrent chromatography. PMID:23833207

An easy-to-use calculating machine to simulate steady state and non-steady-state preparative separations by multiple dual mode counter-current chromatography with semi-continuous loading of feed mixtures.

PubMed

Kostanyan, Artak E; Shishilov, Oleg N

2018-06-01

Multiple dual mode counter-current chromatography (MDM CCC) separation processes with semi-continuous large sample loading consist of a succession of two counter-current steps: with "x" phase (first step) and "y" phase (second step) flow periods. A feed mixture dissolved in the "x" phase is continuously loaded into a CCC machine at the beginning of the first step of each cycle over a constant time with the volumetric rate equal to the flow rate of the pure "x" phase. An easy-to-use calculating machine is developed to simulate the chromatograms and the amounts of solutes eluted with the phases at each cycle for steady-state (the duration of the flow periods of the phases is kept constant for all the cycles) and non-steady-state (with variable duration of alternating phase elution steps) separations. Using the calculating machine, the separation of mixtures containing up to five components can be simulated and designed. Examples of the application of the calculating machine for the simulation of MDM CCC processes are discussed. Copyright © 2018 Elsevier B.V. All rights reserved.

Nonlinear model predictive control applied to the separation of praziquantel in simulated moving bed chromatography.

PubMed

Andrade Neto, A S; Secchi, A R; Souza, M B; Barreto, A G

2016-10-28

An adaptive nonlinear model predictive control of a simulated moving bed unit for the enantioseparation of praziquantel is presented. A first principle model was applied at the proposed purity control scheme. The main concern about this kind of model in a control framework is in regard to the computational effort to solve it; however, a fast enough solution was achieved. In order to evaluate the controller's performance, several cases were simulated, including external pumps and switching valve malfunctions. The problem of plant-model mismatch was also investigated, and for that reason a parameter estimation step was introduced in the control strategy. In every studied scenario, the controller was able to maintain the purity levels at their set points, which were set to 99% and 98.6% for extract and raffinate, respectively. Additionally, fast responses and smooth actuation were achieved. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Nitrogen removal in moving bed sequencing batch reactor using polyurethane foam cubes of various sizes as carrier materials.

PubMed

Lim, Jun-Wei; Seng, Chye-Eng; Lim, Poh-Eng; Ng, Si-Ling; Sujari, Amat-Ngilmi Ahmad

2011-11-01

The performance of moving bed sequencing batch reactors (MBSBRs) added with 8 % (v/v) of polyurethane (PU) foam cubes as carrier media in nitrogen removal was investigated in treating low COD/N wastewater. The results indicate that MBSBR with 8-mL cubes achieved the highest total nitrogen (TN) removal efficiency of 37% during the aeration period, followed by 31%, 24% and 19 % for MBSBRs with 27-, 64- and 125-mL cubes, respectively. The increased TN removal in MBSBRs was mainly due to simultaneous nitrification and denitrification (SND) process which was verified by batch studies. The relatively lower TN removal in MBSBR with larger PU foam cubes was attributed to the observation that larger PU foam cubes were not fully attached by biomass. Higher concentrations of 8-mL PU foam cubes in batch reactors yielded higher TN removal. Copyright © 2011 Elsevier Ltd. All rights reserved.

Power partial-discard strategy to obtain improved performance for simulated moving bed chromatography.

PubMed

Chung, Ji-Woo; Kim, Kyung-Min; Yoon, Tae-Ung; Kim, Seung-Ik; Jung, Tae-Sung; Han, Sang-Sup; Bae, Youn-Sang

2017-12-22

A novel power partial-discard (PPD) strategy was developed as a variant of the partial-discard (PD) operation to further improve the separation performance of the simulated moving bed (SMB) process. The PPD operation varied the flow rates of discard streams by introducing a new variable, the discard amount (DA) as well as varying the reported variable, discard length (DL), while the conventional PD used fixed discard flow rates. The PPD operations showed significantly improved purities in spite of losses in recoveries. Remarkably, the PPD operation could provide more enhanced purity for a given recovery or more enhanced recovery for a given purity than the PD operation. The two variables, DA and DL, in the PPD operation played a key role in achieving the desired purity and recovery. The PPD operations will be useful for attaining high-purity products with reasonable recoveries. Copyright © 2017 Elsevier B.V. All rights reserved.

High temperature thermal energy storage in moving sand

NASA Technical Reports Server (NTRS)

Turner, R. H.; Awaya, H. I.

1978-01-01

Several high-temperature (to 500 C) heat-storage systems using sand as the storage medium are described. The advantages of sand as a storage medium include low cost for sand, widespread availability, non-toxicity, non-degradation characteristics, easy containment, and safety. The systems considered include: stationary sand with closely spaced tubes throughout the volume, the use of a fluidized bed, use of conveyor belt transporter, and the use of a blower rapid transport system. For a stationary sand bed, very close spacing of heat transfer tubes throughout the volume is required, manifesting as high power related system cost. The suggestion of moving sand past or around pipes is intended to reduce the power related costs at the penalty of added system complexity. Preliminary system cost estimates are offered. These rough calculations indicate that mobile sand heat storage systems cost less than the stationary sand approach.

Physicochemical characteristics and microbial community evolution of biofilms during the start-up period in a moving bed biofilm reactor.

PubMed

Zhu, Yan; Zhang, Yan; Ren, Hong-Qiang; Geng, Jin-Ju; Xu, Ke; Huang, Hui; Ding, Li-Li

2015-03-01

This study aimed to investigate biofilm properties evolution coupled with different ages during the start-up period in a moving bed biofilm reactor system. Physicochemical characteristics including adhesion force, extracellular polymeric substances (EPS), morphology as well as volatile solid and microbial community were studied. Results showed that the formation and development of biofilms exhibited four stages, including (I) initial attachment and young biofilm formation, (II) biofilms accumulation, (III) biofilm sloughing and updating, and (IV) biofilm maturation. During the whole start-up period, adhesion force was positively and significantly correlated with the contents of EPS, especially the content of polysaccharide. In addition, increased adhesion force and EPS were beneficial for biofilm retention. Gram-negative bacteria mainly including Sphaerotilus, Zoogloea and Haliscomenobacter were predominant in the initial stage. Actinobacteria was beneficial to resist sloughing. Furthermore, filamentous bacteria were dominant in maturation biofilm. Copyright © 2015 Elsevier Ltd. All rights reserved.

Experimental Exploration of Scale Effects and Factors Controlling Bed Load Sediment Entrainment

NASA Astrophysics Data System (ADS)

Fathel, S. L.; Furbish, D. J.; Schmeeckle, M. W.

2015-12-01

Detailed measurements of individual sand grains moving on a streambed allow us to obtain a deeper understanding of the characteristics of incipient motion and evaluate spatial and temporal trends in particle entrainment. We use bed load particle motions measured from high-speed imaging (250 Hz) of uniform, coarse grained sand from two flume experiments, which have different mean fluid velocities near the bed. Particle tracking reveals more than 6,000 entrainment events in 5 seconds (Run 1) and over 5,000 events in 2 seconds (Run 2). We manually track particles, at sub-pixel resolution, from entrainment to either disentrainment or until the particle leaves the frame. Within these experiments we find that over 90% of all initial motions contain a cross-stream component of motion where approximately a third of the motions may be cross-stream dominated, and furthermore, up to 7% of the motions may be negative (i.e. move backwards). We propose that the variability in the direction of initial motion is, in part, a product of the bed topography, where we find that with increasing mean fluid velocity, the initial motion of the sand particles are less sensitive to bed topography, and are more likely to be dominated by the fluid. The high resolution of this data set, containing positions of particles measured start-to-stop, allows us to calculate the characteristic timescale required for a particle to become streamwise, or fluid, dominated in these systems. We also evaluate these data to further show whether the nature of entrainment is a memoryless, uncorrelated process, a correlated process related to the number of particles already in motion (i.e., possibly reflecting collective entrainment), or some combination of the two. This work suggests that the probability of entrainment depends on physical factors such as bed microtopography and the magnitude of the fluid velocity, in addition to varying with space and time scales.

Repellency of selected chemicals against the bed bug (Hemiptera: Cimicidae).

PubMed

Wang, Changlu; Lü, Lihua; Zhang, Aijun; Liu, Chaofeng

2013-12-01

In recent years, the common bed bug, Cimex lectularius L. (Hemiptera: Cimicidae), became a major public health concern in urban communities. Bed bugs are notoriously difficult to control, and their bites are not tolerated by most people. The public has an urgent need for materials and methods to reduce bed bug introduction and bites during work, travel, or sleep. A repellent product will help achieve these goals by discouraging and preventing bed bugs from moving to a protected area. We evaluated the repellency of three commercially available insect repellent or control materials and five nonregistered materials with the goal of identifying safe and effective bed bug repellents. The two commercial repellent products that contained 7% picaridin or 0.5% permethrin had little repellency against bed bugs. N,N-diethyl-m-toluamide (DEET), the most commonly used insect repellent, provided a high level of repellency against bed bugs. When a host cue (carbon dioxide) was present, the minimum DEET concentration to repel > or = 94% of the bed bugs for a9-h period was 10%. The longevity of repellency of DEET was concentration dependent. At 25% concentration, DEET-treated fabric surface remained highly repellent to bed bugs for a 14-d period. However, DEET has a strong smell and dissolves certain plastic materials. Therefore, we evaluated several odorless, noncorrosive, and potentially effective repellents. Isolongifolenone and isolongifolanone, two natural products and recently reported insect repellents, exhibited strong repellent property against bed bugs but at significantly lower levels than DEET. Three novel potential repellent compounds discovered by Bedoukian Research Inc. (Danbury, CT) exhibited similar level of repellency and longevity as DEET for repelling bed bugs. These nonirritant and odorless compounds are promising candidates as alternatives to DEET for reducing the spread of bed bugs and bed bug bites.

The effect of coarse gravel on cohesive sediment entrapment in an annular flume

NASA Astrophysics Data System (ADS)

Glasbergen, K.; Stone, M.; Krishnappan, B.; Dixon, J.; Silins, U.

2015-03-01

While cohesive sediment generally represents a small fraction (<0.5%) of the total sediment mass stored in gravel-bed rivers, it can strongly influence physical and biogeochemical processes in the hyporheic zone and alter aquatic habitat. This research was conducted to examine mechanisms governing the interaction of cohesive sediments with gravel beds in the Elbow River, Alberta, Canada. A series of erosion and deposition experiments with and without a gravel bed were conducted in a 5-m diameter annular flume. The critical shear stress for deposition and erosion of cohesive sediment without gravel was 0.115 Pa and 0.212 Pa, respectively. In experiments with a gravel bed, cohesive sediment moved from the water column into the gravel bed via the coupling of surface and pore water flow. Once in the gravel bed, cohesive sediments were not mobilized under the maximum applied shear stresses (1.11 Pa) used in the experiment. The gravel bed had an entrapment coefficient (ratio between the entrapment flux and the settling flux) of 0.2. Accordingly, when flow conditions are sufficient to produce a shear stress that will mobilize the armour layer of the gravel bed (>16 Pa), cohesive materials trapped within the gravel bed will be entrained and transported into the Glenmore Reservoir, where sediment-associated nutrients may pose treatment challenges to the drinking water supply.

A generalized volumetric dispersion model for a class of two-phase separation/reaction: finite difference solutions

NASA Astrophysics Data System (ADS)

Siripatana, Chairat; Thongpan, Hathaikarn; Promraksa, Arwut

2017-03-01

This article explores a volumetric approach in formulating differential equations for a class of engineering flow problems involving component transfer within or between two phases. In contrast to conventional formulation which is based on linear velocities, this work proposed a slightly different approach based on volumetric flow-rate which is essentially constant in many industrial processes. In effect, many multi-dimensional flow problems found industrially can be simplified into multi-component or multi-phase but one-dimensional flow problems. The formulation is largely generic, covering counter-current, concurrent or batch, fixed and fluidized bed arrangement. It was also intended to use for start-up, shut-down, control and steady state simulation. Since many realistic and industrial operation are dynamic with variable velocity and porosity in relation to position, analytical solutions are rare and limited to only very simple cases. Thus we also provide a numerical solution using Crank-Nicolson finite difference scheme. This solution is inherently stable as tested against a few cases published in the literature. However, it is anticipated that, for unconfined flow or non-constant flow-rate, traditional formulation should be applied.

Bed material transport in the Virgin River, Utah

USGS Publications Warehouse

Andrews, E.D.

2000-01-01

Detailed information concerning the rate and particle size distribution of bed material transport by streamflows can be very difficult and expensive to obtain, especially where peak streamflows are brief and bed material is poorly sorted, including some very large boulders. Such streams, however, are common in steep, arid watersheds. Any computational approach must consider that (1) only the smaller particle sizes present on the streambed move even during large floods and (2) the largest bed particles exert a significant form drag on the flow. Conventional methods that rely on a single particle size to estimate the skin friction shear stress acting on the mobile fraction of the bed material perform poorly. Instead, for this study, the skin friction shear stress was calculated for the observed range of streamflows by calculating the form drag exerted on the reach‐averaged flow field by all particle sizes. Suspended and bed load transported rates computed from reach‐averaged skin friction shear stress are in excellent agreement with measured transport rates. The computed mean annual bed material load, including both bed load and suspended load, of the East Fork Virgin River for the water years 1992‐1996 was approximately 1.3×10 5 t. A large portion of the bed material load consists of sand‐sized particles, 0.062–1.0 mm in diameter, that are transported in suspension. Such particles, however, constituted only 10% of the surface bed material and less than 25% of the subsurface bed material. The mean annual quantity of bed load transported was 1060 t/yr with a median size of 15 mm.

OPTIMIZATION OF COUNTERCURRENT STAGED PROCESSES.

DTIC Science & Technology

CHEMICAL ENGINEERING , OPTIMIZATION), (*DISTILLATION, OPTIMIZATION), INDUSTRIAL PRODUCTION, INDUSTRIAL EQUIPMENT, MATHEMATICAL MODELS, DIFFERENCE EQUATIONS, NONLINEAR PROGRAMMING, BOUNDARY VALUE PROBLEMS, NUMERICAL INTEGRATION

Nonspherical particles in a pseudo-2D fluidized bed: Experimental study.

PubMed

Mahajan, Vinay V; Padding, Johan T; Nijssen, Tim M J; Buist, Kay A; Kuipers, J A M

2018-05-01

Fluidization is widely used in industries and has been extensively studied, both experimentally and theoretically, in the past. However, most of these studies focus on spherical particles while in practice granules are rarely spherical. Particle shape can have a significant effect on fluidization characteristics. It is therefore important to study the effect of particle shape on fluidization behavior in detail. In this study, experiments in pseudo-2D fluidized beds are used to characterize the fluidization of spherocylindrical (rod-like) Geldart D particles of aspect ratio 4. Pressure drop and optical measurement methods (Digital Image Analysis, Particle Image Velocimetry, Particle Tracking Velocimetry) are employed to measure bed height, particle orientation, particle circulation, stacking, and coordination number. The commonly used correlations to determine the pressure drop across a bed of nonspherical particles are compared to experiments. Experimental observations and measurements have shown that rod-like particles are prone to interlocking and channeling behavior. Well above the minimum fluidization velocity, vigorous bubbling fluidization is observed, with groups of interlocked particles moving upwards, breaking up, being thrown high in the freeboard region and slowly raining down as dispersed phase. At high flowrates, a circulation pattern develops with particles moving up through the center and down at the walls. Particles tend to orient themselves along the flow direction. © 2018 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers , 64: 1573-1590, 2018.

Nonspherical particles in a pseudo‐2D fluidized bed: Experimental study

PubMed Central

Mahajan, Vinay V.; Nijssen, Tim M. J.; Buist, Kay A.; Kuipers, J. A. M.

2018-01-01

Fluidization is widely used in industries and has been extensively studied, both experimentally and theoretically, in the past. However, most of these studies focus on spherical particles while in practice granules are rarely spherical. Particle shape can have a significant effect on fluidization characteristics. It is therefore important to study the effect of particle shape on fluidization behavior in detail. In this study, experiments in pseudo‐2D fluidized beds are used to characterize the fluidization of spherocylindrical (rod‐like) Geldart D particles of aspect ratio 4. Pressure drop and optical measurement methods (Digital Image Analysis, Particle Image Velocimetry, Particle Tracking Velocimetry) are employed to measure bed height, particle orientation, particle circulation, stacking, and coordination number. The commonly used correlations to determine the pressure drop across a bed of nonspherical particles are compared to experiments. Experimental observations and measurements have shown that rod‐like particles are prone to interlocking and channeling behavior. Well above the minimum fluidization velocity, vigorous bubbling fluidization is observed, with groups of interlocked particles moving upwards, breaking up, being thrown high in the freeboard region and slowly raining down as dispersed phase. At high flowrates, a circulation pattern develops with particles moving up through the center and down at the walls. Particles tend to orient themselves along the flow direction. © 2018 The Authors AIChE Journal published by Wiley Periodicals, Inc. on behalf of American Institute of Chemical Engineers AIChE J, 64: 1573–1590, 2018 PMID:29706659

Application of the dynamic model of Saeman to an industrial rotary kiln incinerator: numerical and experimental results.

PubMed

Ndiaye, L G; Caillat, S; Chinnayya, A; Gambier, D; Baudoin, B

2010-07-01

In order to simulate granular materials structure in a rotary kiln under the steady-state regime, a mathematical model has been developed by Saeman (1951). This model enables the calculation of the bed profiles, the axial velocity and solids flow rate along the kiln. This model can be coupled with a thermochemical model, in the case of a reacting moving bed. This dynamic model was used to calculate the bed profile for an industrial size kiln and the model projections were validated by measurements in a 4 m diameter by 16 m long industrial rotary kiln. The effect of rotation speed under solids bed profile and the effect of the feed rate under filling degree were established. On the basis of the calculations and the experimental results a phenomenological relation for the residence time estimation was proposed for the rotary kiln. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Pulling a patient up in bed

MedlinePlus

... from rubbing can scrape or tear the person's skin. Common areas at risk for friction are the shoulders, back, buttocks, elbows, and heels. Never move patients up by grabbing them under their arms and pulling. This can injure their shoulders.

Evaluating De-centralised and Distributional Options for the Distributed Electronic Warfare Situation Awareness and Response Test Bed

DTIC Science & Technology

2013-12-01

effectors (deployed on ground based or aerial platforms) to detect , identify, locate, track or suppress stationary or slow moving surface based RF...ground based or aerial platforms) to detect , identify, locate, track or suppress stationary or slow moving surface based RF emitting targets. In the...Electronic Support EO Electro-Optic FPGAs Field Programmable Gate Arrays IR Infra-red LADAR Laser Detection and Ranging OSX Mac OS X; the apple

Evaluation of multiple-frequency, active and passive acoustics as surrogates for bedload transport

USGS Publications Warehouse

Wood, Molly S.; Fosness, Ryan L.; Pachman, Gregory; Lorang, Mark; Tonolla, Diego

2015-01-01

The use of multiple-frequency, active acoustics through deployment of acoustic Doppler current profilers (ADCPs) shows potential for estimating bedload in selected grain size categories. The U.S. Geological Survey (USGS), in cooperation with the University of Montana (UM), evaluated the use of multiple-frequency, active and passive acoustics as surrogates for bedload transport during a pilot study on the Kootenai River, Idaho, May 17-18, 2012. Four ADCPs with frequencies ranging from 600 to 2000 kHz were used to measure apparent moving bed velocities at 20 stations across the river in conjunction with physical bedload samples. Additionally, UM scientists measured the sound frequencies of moving particles with two hydrophones, considered passive acoustics, along longitudinal transects in the study reach. Some patterns emerged in the preliminary analysis which show promise for future studies. Statistically significant relations were successfully developed between apparent moving bed velocities measured by ADCPs with frequencies 1000 and 1200 kHz and bedload in 0.5 to 2.0 mm grain size categories. The 600 kHz ADCP seemed somewhat sensitive to the movement of gravel bedload in the size range 8.0 to 31.5 mm, but the relation was not statistically significant. The passive hydrophone surveys corroborated the sample results and could be used to map spatial variability in bedload transport and to select a measurement cross-section with moving bedload for active acoustic surveys and physical samples.

Exergy optimization in a steady moving bed heat exchanger.

PubMed

Soria-Verdugo, A; Almendros-Ibáñez, J A; Ruiz-Rivas, U; Santana, D

2009-04-01

This work provides an energy and exergy optimization analysis of a moving bed heat exchanger (MBHE). The exchanger is studied as a cross-flow heat exchanger where one of the phases is a moving granular medium. The optimal MBHE dimensions and the optimal particle diameter are obtained for a range of incoming fluid flow rates. The analyses are carried out over operation data of the exchanger obtained in two ways: a numerical simulation of the steady-state problem and an analytical solution of the simplified equations, neglecting the conduction terms. The numerical simulation considers, for the solid, the convection heat transfer to the fluid and the diffusion term in both directions, and for the fluid only the convection heat transfer to the solid. The results are compared with a well-known analytical solution (neglecting conduction effects) for the temperature distribution in the exchanger. Next, the analytical solution is used to derive an expression for the exergy destruction. The optimal length of the MBHE depends mainly on the flow rate and does not depend on particle diameter unless they become very small (thus increasing sharply the pressure drop). The exergy optimal length is always smaller than the thermal one, although the difference is itself small.

Effects of a malfunctional column on conventional and FeedCol-simulated moving bed chromatography performance.

PubMed

Song, Ji-Yeon; Oh, Donghoon; Lee, Chang-Ha

2015-07-17

The effects of a malfunctional column on the performance of a simulated moving bed (SMB) process were studied experimentally and theoretically. The experimental results of conventional four-zone SMB (2-2-2-2 configuration) and FeedCol operation (2-2-2-2 configuration with one feed column) with one malfunctional column were compared with simulation results of the corresponding SMB processes with a normal column configuration. The malfunctional column in SMB processes significantly deteriorated raffinate purity. However, the extract purity was equivalent or slightly improved compared with the corresponding normal SMB operation because the complete separation zone of the malfunctional column moved to a lower flow rate range in zones II and III. With the malfunctional column configuration, FeedCol operation gave better experimental performance (up to 7%) than conventional SMB operation because controlling product purity with FeedCol operation was more flexible through the use of two additional operating variables, injection time and injection length. Thus, compared with conventional SMB separation, extract with equivalent or slightly better purity could be produced from FeedCol operation even with a malfunctional column, while minimizing the decrease in raffinate purity (less than 2%). Copyright © 2015 Elsevier B.V. All rights reserved.

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

USGS Publications Warehouse

Gaeuman, D.; Jacobson, R.B.

2007-01-01

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

Fluidized bed and method and system for gas component capture

DOEpatents

Krutka, Holly; Wilson, Cody; Starns, Travis

2016-05-31

The present disclosure is directed to a process that allows dry sorbents to remove a target constituent, such as carbon dioxide (CO.sub.2), from a gas stream. A staged fluidized bed separator enables gas and sorbent to move in opposite directions. The sorbent is loaded with target constituent in the separator. It is then transferred to a regenerator where the target constituent is stripped. The temperature of the separator and regenerator are controlled. After it is removed from the regenerator, the sorbent is then transferred back to the separator.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stoltzfus-Dueck, T.; Scott, B.

An often-neglected portion of the radialmore » $$\\boldsymbol{E}\\times \\boldsymbol{B}$$ drift is shown to drive an outward flux of co-current momentum when free energy is transferred from the electrostatic potential to ion parallel flows. This symmetry breaking is fully nonlinear, not quasilinear, necessitated simply by free-energy balance in parameter regimes for which significant energy is dissipated via ion parallel flows. The resulting rotation peaking is counter-current and has a scaling and order of magnitude that are comparable with experimental observations. Finally, the residual stress becomes inactive when frequencies are much higher than the ion transit frequency, which may explain the observed relation of density peaking and counter-current rotation peaking in the core.« less

Preparative high-speed counter-current chromatography for purification of shikonin from the Chinese medicinal plant Lithospermum erythrorhizon.

PubMed

Lu, Hai-Tao; Jiang, Yue; Chen, Feng

2004-01-09

The bioactive compound shikonin was successfully isolated and purified from the crude extract of the traditional Chinese medicinal plant Lithospermum erythrorhizon Sieb. et Zucc. by preparative high-speed counter-current chromatography (HSCCC). The preparative HSCCC was performed using a two-phase solvent system composed of n-hexane-ethylacetate-ethanol-water (16:14:14:5 (v/v)). A total amount of 19.6 mg of shikonin at 98.9% purity was obtained from 52 mg of the crude extract (containing 38.9% shikonin) with 96.9% recovery. The preparative isolation and purification of shikonin by HSCCC was completed in 200 min in a one-step separation.

Transport of fine sediment over a coarse, immobile riverbed

USGS Publications Warehouse

Grams, Paul E.; Wilcock, Peter R.

2014-01-01

Sediment transport in cobble-boulder rivers consists mostly of fine sediment moving over a coarse, immobile bed. Transport rate depends on several interrelated factors: boundary shear stress, the grain size and volume of fine sediment, and the configuration of fine sediment into interstitial deposits and bed forms. Existing models do not incorporate all of these factors. Approaches that partition stress face a daunting challenge because most of the boundary shear is exerted on immobile grains. We present an alternative approach that divides the bed into sand patches and interstitial deposits and is well constrained by two clear end-member cases: full sand cover and absence of sand. Entrainment from sand patches is a function of their aerial coverage. Entrainment from interstices among immobile grains is a function of sand elevation relative to the size of the immobile grains. The bed-sand coverage function is used to predict the ratio of the rate of entrainment from a partially covered bed to the rate of entrainment from a completely sand-covered bed, which is determined using a standard sand transport model. We implement the bed-sand coverage function in a morphodynamic routing model and test it against observations of sand bed elevation and suspended sand concentration for conditions of nonuniform fine sediment transport in a large flume with steady uniform flow over immobile hemispheres. The results suggest that this approach may provide a simple and robust method for predicting the transport and migration of fine sediment through rivers with coarse, immobile beds.

Brief notes on habitat geology and clay pipe habitat on Stellwagen Bank

USGS Publications Warehouse

Valentine, Page C.; Dorsey, Eleanor M.; Pederson, Judith

1998-01-01

In our studies of sea floor habitats, my colleagues and I use both biological and geological approaches. We call our studies “habitat geology,” a term coined by a biologist friend of mine. We view it as the study of sea floor materials and biological and geological processes that influence where species live. Some of the factors that we consider are the following:composition of the sea bed, which ranges from mud to sand, gravel, bedrock, and shell beds;shape and steepness of the bottom;roughness of the bottom, which is enhanced by the presence of cobbles, boulders, sand waves and ripples, burrows into the bottom, and species that extend above the bottom;bottom currents generated by storm waves and tides, which can move sediment and expose or cover habitats; andthe way in which the sea bed is utilized by species.In addition, we take into account the impact of sea bed disturbance by bottom fishing trawls and dredges. Habitats characterized by attached and burrowing species that protrude above the sea bed appear to be most vulnerable to disturbance.

Modelling and simulation of wood chip combustion in a hot air generator system.

PubMed

Rajika, J K A T; Narayana, Mahinsasa

2016-01-01

This study focuses on modelling and simulation of horizontal moving bed/grate wood chip combustor. A standalone finite volume based 2-D steady state Euler-Euler Computational Fluid Dynamics (CFD) model was developed for packed bed combustion. Packed bed combustion of a medium scale biomass combustor, which was retrofitted from wood log to wood chip feeding for Tea drying in Sri Lanka, was evaluated by a CFD simulation study. The model was validated by the experimental results of an industrial biomass combustor for a hot air generation system in tea industry. Open-source CFD tool; OpenFOAM was used to generate CFD model source code for the packed bed combustion and simulated along with an available solver for free board region modelling in the CFD tool. Height of the packed bed is about 20 cm and biomass particles are assumed to be spherical shape with constant surface area to volume ratio. Temperature measurements of the combustor are well agreed with simulation results while gas phase compositions have discrepancies. Combustion efficiency of the validated hot air generator is around 52.2 %.

Intracellular Calcium Release Channels Mediate Their Own Countercurrent: The Ryanodine Receptor Case Study

PubMed Central

Gillespie, Dirk; Fill, Michael

2008-01-01

Intracellular calcium release channels like ryanodine receptors (RyRs) and inositol trisphosphate receptors (IP3Rs) mediate large Ca2+ release events from Ca2+ storage organelles lasting >5 ms. To have such long-lasting Ca2+ efflux, a countercurrent of other ions is necessary to prevent the membrane potential from becoming the Ca2+ Nernst potential in <1 ms. A recent model of ion permeation through a single, open RyR channel is used here to show that the vast majority of this countercurrent is conducted by the RyR itself. Consequently, changes in membrane potential are minimized locally and instantly, assuring maintenance of a Ca2+-driving force. This RyR autocountercurrent is possible because of the poor Ca2+ selectivity and high conductance for both monovalent and divalent cations of these channels. The model shows that, under physiological conditions, the autocountercurrent clamps the membrane potential near 0 mV within ∼150 μs. Consistent with experiments, the model shows how RyR unit Ca2+ current is defined by luminal [Ca2+], permeable ion composition and concentration, and pore selectivity and conductance. This very likely is true of the highly homologous pore of the IP3R channel. PMID:18621826

Separation and purification of four flavonol diglucosides from the flower of Meconopsis integrifolia by high-speed counter-current chromatography.

PubMed

Huang, Yanfei; Han, Yatao; Chen, Keli; Huang, Bisheng; Liu, Yuan

2015-12-01

Flavonoids are the main components of Meconopsis integrifolia (Maxim.) Franch, which is a traditional Tibetan medicine. However, traditional chromatography separation requires a large quantity of raw M. integrifolia and is very time consuming. Herein, we applied high-speed counter-current chromatography in the separation and purification of flavonoids from the ethanol extracts of M. integrifolia flower. Ethyl acetate/n-butanol/water (2:3:5, v/v/v) was selected as the optimum solvent system to purify the four components, namely quercetin-3-O-β-d-glucopyrannosy-(1→6)-β-d-glucopyranoside (compound 1, 60 mg), quercetin 3-O-[2'''-O-acetyl-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside (compound 2, 40 mg), quercetin 3-O-[3'''-O-acetyl-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside (compound 3, 11 mg), and quercetin 3-O-[6'''-O-acetyl-β-d-glucopyranosyl-(1→6)-β-d-glucopyranoside (compound 4, 16 mg). Among the four compounds, 3 and 4 were new acetylated flavonol diglucosides. After the high-speed counter-current chromatography separation, the purities of the four flavonol diglucosides were 98, 95, 90, and 92%, respectively. The structures of these compounds were identified by mass spectrometry and NMR spectroscopy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effects of dialysate flow configurations in continuous renal replacement therapy on solute removal: computational modeling.

PubMed

Kim, Jeong Chul; Cruz, Dinna; Garzotto, Francesco; Kaushik, Manish; Teixeria, Catarina; Baldwin, Marie; Baldwin, Ian; Nalesso, Federico; Kim, Ji Hyun; Kang, Eungtaek; Kim, Hee Chan; Ronco, Claudio

2013-01-01

Continuous renal replacement therapy (CRRT) is commonly used for critically ill patients with acute kidney injury. During treatment, a slow dialysate flow rate can be applied to enhance diffusive solute removal. However, due to the lack of the rationale of the dialysate flow configuration (countercurrent or concurrent to blood flow), in clinical practice, the connection settings of a hemodiafilter are done depending on nurse preference or at random. In this study, we investigated the effects of flow configurations in a hemodiafilter during continuous venovenous hemodialysis on solute removal and fluid transport using computational fluid dynamic modeling. We solved the momentum equation coupling solute transport to predict quantitative diffusion and convection phenomena in a simplified hemodiafilter model. Computational modeling results showed superior solute removal (clearance of urea: 67.8 vs. 45.1 ml/min) and convection (filtration volume: 29.0 vs. 25.7 ml/min) performances for the countercurrent flow configuration. Countercurrent flow configuration enhances convection and diffusion compared to concurrent flow configuration by increasing filtration volume and equilibrium concentration in the proximal part of a hemodiafilter and backfiltration of pure dialysate in the distal part. In clinical practice, the countercurrent dialysate flow configuration of a hemodiafilter could increase solute removal in CRRT. Nevertheless, while this configuration may become mandatory for high-efficiency treatments, the impact of differences in solute removal observed in slow continuous therapies may be less important. Under these circumstances, if continuous therapies are prescribed, some of the advantages of the concurrent configuration in terms of simpler circuit layout and simpler machine design may overcome the advantages in terms of solute clearance. Different dialysate flow configurations influence solute clearance and change major solute removal mechanisms in the proximal and distal parts of a hemodiafilter. Advantages of each configuration should be balanced against the overall performance of the treatment and its simplicity in terms of treatment delivery and circuit handling procedures. Copyright © 2013 S. Karger AG, Basel.

Will river erosion below the Three Gorges Dam stop in the middle Yangtze?

NASA Astrophysics Data System (ADS)

Lai, X.; Yin, D.; Finlayson, B. L.; Wei, T.; Li, M.; Yuan, W.; Yang, S.; Dai, Z.; Gao, S.; Chen, Z.

2017-11-01

The environmental impact of the Three Gorges Dam has been a subject of vigorous academic, political and social debate since its inception. This includes the key issue of post-dam river channel erosion, which was predicted by the feasibility study to extend to the river mouth. In this paper we examine the geomorphic response of the channel of the middle Yangtze for 660 km downstream of the dam. Using data on channel characteristics, bed material and sediment transport, we show that in the decade following the dam closure, pre-dam seasonal erosion has been replaced by year-round erosion, a pattern most marked at the upstream end of the study area. The sediment carrying capacity of the river channel has been largely reduced below the dam. The locus of bed scour has moved progressively downstream, ceasing as the bed material became too coarse to be transported (e.g. D50: 0.29 mm pre-dam coarsened to 20 mm below the dam by 2008). About 400 km below the dam there is a reduction in channel slope that changes the sediment carrying capacity from 0.25 kg m-3 to only about 0.05 kg m-3, which is insufficient to move bed sediment. The new long-term hydro-morphological equilibrium that will be established in this section of the middle Yangtze will prevent the further incision downstream initiated by the Three Gorges Dam. The results suggest that the full extent of adverse environmental impact predicted by the pre-dam studies will not eventuate.

Direct Reduction of Iron Ore

NASA Astrophysics Data System (ADS)

Small, M.

1981-04-01

In the search for a pure, available iron source, steelmakers are focusing their attention on Directly Reduced Iron (DRI). This material is produced by the reaction of a low gangue iron ore with a hydrocarbonaceous substance. Commercially, DRI is generated in four different reactors: shaft (moving-bed), rotary kiln, fluidized bed, and retort (fixed-bed). Annual worldwide production capacity approaches 33 million metric tons. Detailed assessments have been made of the uses of DRI, especially as a substitute for scrap in electric furnace (EF) steelmaking. DRI is generally of a quality superior to current grades of scrap, with steels produced more efficiently in the EF and containing lower levels of impurities. However, present economics favor EF steel production with scrap. But this situation could change within this decade because of a developing scarcity of good quality scrap.

The Importance of Splat Events to the Spatiotemporal Structure of Near-Bed Fluid Velocity and Bed Load Motion Over Bed Forms: Laboratory Experiments Downstream of a Backward Facing Step

NASA Astrophysics Data System (ADS)

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

2017-12-01

Flow separation/reattachment on the lee side of alluvial bed forms is known to produce a complex turbulence field, but the spatiotemporal details of the associated patterns of bed load sediment transported remain largely unknown. Here we report turbulence-resolving, simultaneous measurements of bed load motion and near-bed fluid velocity downstream of a backward facing step in a laboratory flume. Two synchronized high-speed video cameras simultaneously observed bed load motion and the motion of neutrally buoyant particles in a laser light sheet 6 mm above the bed at 250 frames/s downstream of a 3.8 cm backward facing step. Particle Imaging Velocimetry (PIV) and Acoustic Doppler Velocimetry (ADV) were used to characterize fluid turbulent patterns, while manual particle tracking techniques were used to characterize bed load transport. Octant analysis, conducted using ADV data, coupled with Markovian sequence probability analysis highlights differences in the flow near reattachment versus farther downstream. Near reattachment, three distinct flow patterns are apparent. Farther downstream we see the development of a dominant flow sequence. Localized, intermittent, high-magnitude transport events are more apparent near flow reattachment. These events are composed of streamwise and cross-stream fluxes of comparable magnitudes. Transport pattern and fluid velocity data are consistent with the existence of permeable "splat events," wherein a volume of fluid moves toward and impinges on the bed (sweep) causing a radial movement of fluid in all directions around the point of impingement (outward interaction). This is congruent with flow patterns, identified with octant analysis, proximal to flow reattachment.

Achieving nitritation in a continuous moving bed biofilm reactor at different temperatures through ratio control.

PubMed

Bian, Wei; Zhang, Shuyan; Zhang, Yanzhuo; Li, Wenjing; Kan, Ruizhe; Wang, Wenxiao; Zheng, Zhaoming; Li, Jun

2017-02-01

A ratio control strategy was implemented in a continuous moving bed biofilm reactor (MBBR) to investigate the response to different temperatures. The control strategy was designed to maintain a constant ratio between dissolved oxygen (DO) and total ammonia nitrogen (TAN) concentrations. The results revealed that a stable nitritation in a biofilm reactor could be achieved via ratio control, which compensated the negative influence of low temperatures by stronger oxygen-limiting conditions. Even with a temperature as low as 6°C, stable nitritation could be achieved when the controlling ratio did not exceed 0.17. Oxygen-limiting conditions in the biofilm reactor were determined by the DO/TAN concentrations ratio, instead of the mere DO concentration. This ratio control strategy allowed the achievement of stable nitritation without complete wash-out of NOB from the reactor. Through the ratio control strategy full nitritation of sidestream wastewater was allowed; however, for mainstream wastewater, only partial nitritation was recommended. Copyright © 2016 Elsevier Ltd. All rights reserved.

Influence of carrier filling ratio on the performance of moving bed biofilm reactor in treating coking wastewater.

PubMed

Gu, Qiyuan; Sun, Tichang; Wu, Gen; Li, Mingyue; Qiu, Wei

2014-08-01

This study aims to evaluate the effect of carrier filling ratio on the performance of a moving bed biofilm reactor in degrading chemical oxygen demand, phenol, thiocyanate, and ammonia from coking wastewater at 20h of hydraulic retention time. The operational experiments under different carrier filling ratios ranging from 20% to 60% were investigated. The maximum removal efficiency of 89%, 99% and 99% for COD, phenol and thiocyanate, and minimum sensitivity to the increasing contaminants concentration in the influent were achieved at 50% carrier filling ratio. The Haldane competitive substrate inhibition kinetics model was used to describe the relationship between the oxygen uptake rate of ammonium oxidizers and the concentration of free ammonium. The highest biofilm microbial community functional diversity (Shannon's diversity index, H') and evenness (Shannon's evenness index, E') were obtained at 50% carrier filling ratio in all runs using a Biolog ECO microplate. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization of bacterial structures in two-stage moving-bed biofilm reactor (MBBR) during nitrification of the landfill leachate.

PubMed

Ciesielski, Slawomir; Kulikowska, Dorota; Kaczowka, Ewelina; Kowal, Przemysław

2010-07-01

Differences in DNA banding patterns, obtained by ribosomal intergenic spacer analysis (RISA), and nitrification were followed in a moving-bed biofilm reactor (MBBR) receiving municipal landfill leachate. Complete nitrification (> 99%) to nitrate was obtained in the two-stage MBBR system with an ammonium load of 1.09 g N-NH(4)/m(2).d. Increasing the ammonium load to 2.03 g N-NH(4)/m(2).d or more caused a decline in process efficiency to 70-86%. Moreover, at the highest ammonium load (3.76 g N-NH(4)/m(2).d), nitrite was the predominant product of nitrification. Community succession was evident in both compartments in response to changes in ammonium load. Non-metric multidimensional scaling (NMDS) supported by similarity analysis (ANOSIM) showed that microbial biofilm communities differed between compartments. The microbial biofilm was composed mainly of ammonia-oxidizing bacteria (AOB), with Nitrosomonas europeae and N. eutropha being most abundant. These results suggest that high ammonium concentrations select for particular AOB strains.

Prediction of moving bed biofilm reactor (MBBR) performance for the treatment of aniline using artificial neural networks (ANN).

PubMed

Delnavaz, M; Ayati, B; Ganjidoust, H

2010-07-15

In this study, the results of 1-year efficiency forecasting using artificial neural networks (ANN) models of a moving bed biofilm reactor (MBBR) for a toxic and hard biodegradable aniline removal were investigated. The reactor was operated in an aerobic batch and continuous condition with 50% by volume which was filled with light expanded clay aggregate (LECA) as carrier. Efficiency evaluation of the reactors was obtained at different retention time (RT) of 8, 24, 48 and 72 h with an influent COD from 100 to 4000 mg/L. Exploratory data analysis was used to detect relationships between the data and dependent evaluated one. The appropriate architecture of the neural network models was determined using several steps of training and testing of the models. The ANN-based models were found to provide an efficient and a robust tool in predicting MBBR performance for treating aromatic amine compounds. 2010 Elsevier B.V. All rights reserved.

Removal of pharmaceuticals in conventionally treated wastewater by a polishing moving bed biofilm reactor (MBBR) with intermittent feeding.

PubMed

Tang, Kai; Ooi, Gordon T H; Litty, Klaus; Sundmark, Kim; Kaarsholm, Kamilla M S; Sund, Christina; Kragelund, Caroline; Christensson, Magnus; Bester, Kai; Andersen, Henrik R

2017-07-01

Previous studies have demonstrated that aerobic moving bed biofilm reactors (MBBRs) remove pharmaceuticals better than activated sludge. Thus we used a MBBR system to polish the effluent of an activated sludge wastewater treatment plant. To overcome that effluent contains insufficient organic matter to sustain enough biomass, the biofilm was intermittently fed with raw wastewater. The capacity of pharmaceutical degradation was investigated by spiking pharmaceuticals. Actual removal during treatment was assessed by sampling the inlets and outlets of reactors. The removal of the majority of pharmaceuticals was enhanced through the intermittent feeding of the MBBR. First-order rate constants for pharmaceutical removal, normalised to biomass, were significantly higher compared to other studies on activated sludge and suspended biofilms, especially for diclofenac, metoprolol and atenolol. Due to the intermittently feeding, degradation of diclofenac occurred with a half-life of only 2.1h and was thus much faster than any hitherto described wastewater bioreactor treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

New functional biocarriers for enhancing the performance of a hybrid moving bed biofilm reactor-membrane bioreactor system.

PubMed

Deng, Lijuan; Guo, Wenshan; Ngo, Huu Hao; Zhang, Xinbo; Wang, Xiaochang C; Zhang, Qionghua; Chen, Rong

2016-05-01

In this study, new sponge modified plastic carriers for moving bed biofilm reactor (MBBR) was developed. The performance and membrane fouling behavior of a hybrid MBBR-membrane bioreactor (MBBR-MBR) system were also evaluated. Comparing to the MBBR with plastic carriers (MBBR), the MBBR with sponge modified biocarriers (S-MBBR) showed better effluent quality and enhanced nutrient removal at HRTs of 12h and 6h. Regarding fouling issue of the hybrid systems, soluble microbial products (SMP) of the MBR unit greatly influenced membrane fouling. The sponge modified biocarriers could lower the levels of SMP in mixed liquor and extracellular polymeric substances in activated sludge, thereby mitigating cake layer and pore blocking resistances of the membrane. The reduced SMP and biopolymer clusters in membrane cake layer were also observed. The results demonstrated that the sponge modified biocarriers were capable of improving overall MBBR performance and substantially alleviated membrane fouling of the subsequent MBR unit. Copyright © 2016 Elsevier Ltd. All rights reserved.

Combination of upflow anaerobic sludge blanket (UASB) reactor and partial nitritation/anammox moving bed biofilm reactor (MBBR) for municipal wastewater treatment.

PubMed

Malovanyy, Andriy; Yang, Jingjing; Trela, Jozef; Plaza, Elzbieta

2015-03-01

In this study the combination of an upflow anaerobic sludge blanket (UASB) reactor and a deammonification moving bed biofilm reactor (MBBR) for mainstream wastewater treatment was tested. The competition between aerobic ammonium oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) was studied during a 5months period of transition from reject water to mainstream wastewater followed by a 16months period of mainstream wastewater treatment. The decrease of influent ammonium concentration led to a wash-out of suspended biomass which had a major contribution to nitrite production. Influence of a dissolved oxygen concentration and a transient anoxia mechanism of NOB suppression were studied. It was shown that anoxic phase duration has no effect on NOB metabolism recovery and oxygen diffusion rather than affinities of AOB and NOB to oxygen determine the rate of nitrogen conversion in a biofilm system. Anammox activity remained on the level comparable to reject water treatment systems. Copyright © 2014 Elsevier Ltd. All rights reserved.

Comparative analysis of the bacterial diversity in a lab-scale moving bed biofilm reactor (MBBR) applied to treat urban wastewater under different operational conditions.

PubMed

Calderón, Kadiya; Martín-Pascual, Jaime; Poyatos, José Manuel; Rodelas, Belén; González-Martínez, Alejandro; González-López, Jesús

2012-10-01

Different types of carriers were tested as support material in a lab-scale moving bed biofilm reactor (MBBR) used to treat urban wastewater under three different conditions of hydraulic retention time (HRT) and carrier filling ratios (FR). The bacterial diversity developed on the biofilms responsible of the treatment was studied using a cultivation-independent approach based on the polymerase chain reaction-temperature gradient gel electrophoresis technique (PCR-TGGE). Cluster analysis of TGGE fingerprints showed significant differences of community structure dependent upon the different operational conditions applied. Redundancy analysis (RDA) was used to determine the relationship between the operational conditions (type of carrier, HRT, FR) and bacterial biofilm diversity, demonstrating a significant effect of FR=50%. Phylogenetic analysis of PCR-reamplified and sequenced TGGE bands revealed that the prevalent Bacteria populations in the biofilm were related to Betaproteobacteria (46%), Firmicutes (34%),Alphaproteobacteria (14%) and Gammaproteobacteria (9%). Copyright © 2012 Elsevier Ltd. All rights reserved.

Utilization of moving bed biofilm reactor for industrial wastewater treatment containing ethylene glycol: kinetic and performance study.

PubMed

Hassani, Amir Hessam; Borghei, Seyed Mehdi; Samadyar, Hassan; Ghanbari, Bastam

2014-01-01

One of the requirements for environmental engineering, which is currently being considered, is the removal of ethylene glycol (EG) as a hazardous environmental pollutant from industrial wastewater. Therefore, in a recent study, a moving bed biofilm reactor (MBBR) was applied at pilot scale to treat industrial effluents containing different concentrations of EG (600, 800, 1200, and 1800 mg L-1 ). The removal efficiency and kinetic analysis of the system were examined at different hydraulic retention times of 6, 8, 10, and 12 h as well as influent chemical oxygen demand (COD) ranged between values of 1000 and 3000mg L-1. In minimum and maximum COD Loadings, the MBBR showed 95.1% and 60.7% removal efficiencies, while 95.9% and 66.2% EG removal efficiencies were achieved in the lowest and highest EG concentrations. The results of the reactor modelling suggested compliance of the well-known modified Stover-Kincannon model with the system.

High-rate wastewater treatment combining a moving bed biofilm reactor and enhanced particle separation.

PubMed

Helness, H; Melin, E; Ulgenes, Y; Järvinen, P; Rasmussen, V; Odegaard, H

2005-01-01

Many cities around the world are looking for compact wastewater treatment alternatives since space for treatment plants is becoming scarce. In this paper development of a new compact, high-rate treatment concept with results from experiments in lab-scale and pilot-scale are presented. The idea behind the treatment concept is that coagulation/floc separation may be used to separate suspended and colloidal matter (resulting in > 70% organic matter removal in normal wastewater) while a high-rate biofilm process (based on Moving Bed biofilm reactors) may be used for removing low molecular weight, easily biodegradable, soluble organic matter. By using flotation for floc/biomass separation, the total residence time for a plant according to this concept will normally be < 1 hour. A cationic polymer combined with iron is used as coagulant at low dosages (i.e. 1-2 mg polymer/l, 5-10 mg Fe/l) resulting in low sludge production (compared to conventional chemical treatment) and sufficient P-removal.

Treatment of oilfield wastewater in moving bed biofilm reactors using a novel suspended ceramic biocarrier.

PubMed

Dong, Zhiyong; Lu, Mang; Huang, Wenhui; Xu, Xiaochun

2011-11-30

In this study, a novel suspended ceramic carrier was prepared, which has high strength, optimum density (close to water), and high porosity. Two different carriers, unmodified and sepiolite-modified suspended ceramic carriers were used to feed two moving bed biofilm reactors (MBBRs) with a filling fraction of 50% to treat oilfield produced water. The hydraulic retention time (HRT) was varied from 36 to 10h. The results, during a monitoring period of 190 days, showed that removal efficiency of chemical oxygen demand was the highest in reactor 3 filled with the sepiolite-modified carriers, followed by reactor 2 filled with the unmodified carriers, with the lowest in reactor 1 (activated sludge reactor), at an HRT of 10h. Similar trends were found in the removal efficiencies of ammonia nitrogen and polycyclic aromatic hydrocarbons. Reactor 3 was more shock resistant than reactors 2 and 1. The results indicate that the suspended ceramic carrier is an excellent MBBR carrier. Copyright © 2011 Elsevier B.V. All rights reserved.

Removal and fate of micropollutants in a sponge-based moving bed bioreactor.

PubMed

Luo, Yunlong; Guo, Wenshan; Ngo, Huu Hao; Nghiem, Long Duc; Hai, Faisal Ibney; Kang, Jinguo; Xia, Siqing; Zhang, Zhiqiang; Price, William Evan

2014-05-01

This study investigated the removal of micropollutants using polyurethane sponge as attached-growth carrier. Batch experiments demonstrated that micropollutants could adsorb to non-acclimatized sponge cubes to varying extents. Acclimatized sponge showed significantly enhanced removal of some less hydrophobic compounds (log D<2.5), such as ibuprofen, acetaminophen, naproxen, and estriol, as compared with non-acclimatized sponge. The results for bench-scale sponge-based moving bed bioreactor (MBBR) system elucidated compound-specific variation in removal, ranging from 25.9% (carbamazepine) to 96.8% (β-Estradiol 17-acetate) on average. In the MBBR system, biodegradation served as a major removal pathway for most compounds. However, sorption to sludge phase was also a notable removal mechanism of some persistent micropollutants. Particularly, carbamazepine, ketoprofen and pentachlorophenol were found at high concentrations (7.87, 6.05 and 5.55 μg/g, respectively) on suspended biosolids. As a whole, the effectiveness of MBBR for micropollutant removal was comparable with those of activated sludge processes and MBRs. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of C/N shock variation on the performances of a moving bed membrane bioreactor.

PubMed

Di Trapani, Daniele; Di Bella, Gaetano; Mannina, Giorgio; Torregrossa, Michele; Viviani, Gaspare

2015-08-01

The effect of a sharp variation of C/N ratio in a moving bed membrane bioreactor (MB-MBR) pilot plant treating high strength wastewater has been investigated. The experimental campaign was divided into two periods, each characterized by a different C/N ratio (namely, 2.5 and 15, Period 1 and Period 2, respectively). The MB-MBR system was analyzed in terms of organic carbon removal, nitrification efficiency, biokinetic activity and fouling behavior. The results showed that the nitrification process was severely affected by lower C/N value and by high concentration of ammonia. It was noticed an extensive stress effect on the autotrophic bacteria. Furthermore, it was observed an increase of the resistance related to particle deposition into membrane pores, likely due to a worsening of the cake layer features, with a reduction of the "pre-filter" effect, also related to the increase of the total Extracellular Polymeric Substances production with the C/N ratio. Copyright © 2015 Elsevier Ltd. All rights reserved.

Screening selectively harnessed environmental microbial communities for biodegradation of polycyclic aromatic hydrocarbons in moving bed biofilm reactors.

PubMed

Demeter, Marc A; Lemire, Joseph A; Mercer, Sean M; Turner, Raymond J

2017-03-01

Bacteria are often found tolerating polluted environments. Such bacteria may be exploited to bioremediate contaminants in controlled ex situ reactor systems. One potential strategic goal of such systems is to harness microbes directly from the environment such that they exhibit the capacity to markedly degrade organic pollutants of interest. Here, the use of biofilm cultivation techniques to inoculate and activate moving bed biofilm reactor (MBBR) systems for the degradation of polycyclic aromatic hydrocarbons (PAHs) was explored. Biofilms were cultivated from 4 different hydrocarbon contaminated sites using a minimal medium spiked with the 16 EPA identified PAHs. Overall, all 4 inoculant sources resulted in biofilm communities capable of tolerating the presence of PAHs, but only 2 of these exhibited enhanced PAH catabolic gene prevalence coupled with significant degradation of select PAH compounds. Comparisons between inoculant sources highlighted the dependence of this method on appropriate inoculant screening and biostimulation efforts. Copyright © 2016 Elsevier Ltd. All rights reserved.

Control technique for planetary rover

NASA Technical Reports Server (NTRS)

Nakatani, Ichiro; Kubota, Takashi; Adachi, Tadashi; Saitou, Hiroaki; Okamoto, Sinya

1994-01-01

Beginning next century, several schemes for sending a planetary rover to the moon or Mars are being planned. As part of the development program, autonomous navigation technology is being studied to allow the rover the ability to move autonomously over a long range of unknown planetary surface. In the previous study, we ran the autonomous navigation experiment on an outdoor test terrain by using a rover test-bed that was controlled by a conventional sense-plan-act method. In some cases during the experiment, a problem occurred with the rover moving into untraversable areas. To improve this situation, a new control technique has been developed that gives the rover the ability of reacting to the outputs of the proximity sensors, a reaction behavior if you will. We have developed a new rover test-bed system on which an autonomous navigation experiment was performed using the newly developed control technique. In this outdoor experiment, the new control technique effectively produced the control command for the rover to avoid obstacles and be guided to the goal point safely.

Demonstration of a 1 MWe biomass power plant at USMC Base Camp Lejeune. Report for July 1994-May 1997

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cleland, J.; Purvis, C.R.

1998-06-01

The paper discusses a biomass energy conversion project being sponsored by EPA to demonstrate an enviromentally and economically sound electrical power option for government installations, industrial sites, rural cooperatives, small municipalities, and developing countries. Wood gasification combined with internal combustion engines was chosen because of (1) recent improvements in gas cleaning, (2) simple economical operation for units < 10 MW, and (3) the option of a clean cheap fuel for the many existing facilities generating expensive electricity from petroleum fuels with reciprocating engines. The plant incorporates a downdraft, moving-bed gasifier utilizing hogged waste wood from the Marine Corps Base atmore » Camp Lejeune, NC. A moving-bed bulk wood dryer and both spark ignition and diesel engines are included. Unique process design features are described briefly, relative to the gasifier, wood drying, tar separation, and process control. A test plan for process optimization and demonstration of reliability, economics, and environmental impact is outlined.« less

The characteristics of extracellular polymeric substances and soluble microbial products in moving bed biofilm reactor-membrane bioreactor.

PubMed

Duan, Liang; Jiang, Wei; Song, Yonghui; Xia, Siqing; Hermanowicz, Slawomir W

2013-11-01

The characteristics of extracellular polymeric substances (EPS) and soluble microbial products (SMP) in conventional membrane bioreactor (MBR) and in moving bed biofilm reactor-membrane bioreactors (MBBR-MBR) were investigated in long-term (170 days) experiments. The results showed that all reactors had high removal efficiency of ammonium and COD, despite very different fouling conditions. The MBBR-MBR with media fill ratio of 26.7% had much lower total membrane resistance and no obvious fouling were detected during the whole operation. In contrast, MBR and MBBR-MBR with lower and higher media fill experienced more significant fouling. Low fouling at optimum fill ratio may be due to the higher percentage of small molecular size (<1 kDa) and lower percentage of large molecular size (>100 kDa) of EPS and SMP in the reactor. The composition of EPS and SMP affected fouling due to different O-H bonds in hydroxyl functional groups, and less polysaccharides and lipids. Copyright © 2013 Elsevier Ltd. All rights reserved.

Optimization of startup and shutdown operation of simulated moving bed chromatographic processes.

PubMed

Li, Suzhou; Kawajiri, Yoshiaki; Raisch, Jörg; Seidel-Morgenstern, Andreas

2011-06-24

This paper presents new multistage optimal startup and shutdown strategies for simulated moving bed (SMB) chromatographic processes. The proposed concept allows to adjust transient operating conditions stage-wise, and provides capability to improve transient performance and to fulfill product quality specifications simultaneously. A specially tailored decomposition algorithm is developed to ensure computational tractability of the resulting dynamic optimization problems. By examining the transient operation of a literature separation example characterized by nonlinear competitive isotherm, the feasibility of the solution approach is demonstrated, and the performance of the conventional and multistage optimal transient regimes is evaluated systematically. The quantitative results clearly show that the optimal operating policies not only allow to significantly reduce both duration of the transient phase and desorbent consumption, but also enable on-spec production even during startup and shutdown periods. With the aid of the developed transient procedures, short-term separation campaigns with small batch sizes can be performed more flexibly and efficiently by SMB chromatography. Copyright © 2011 Elsevier B.V. All rights reserved.

Coking properties of coal under pressure and their influence on moving-bed gasification. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lancet, M.S.; Curran, G.P.; Sim, F.A.

1982-08-01

The coking properties of seven bituminous coals, including three Eastern US coals, one Midwestern US coal, a Western US coal and two from the UK were studied with respect to the possible utilization of these coals in moving bed gasifier systems. Complete physical, chemical and petrographic analyses were obtained for each coal in addition to the highly specialized CCDC simulated gasifier coking test data. The effects of total pressure, hydrogen partial pressure, heating rate and the addition of gob and tar on the fluidity and swelling properties of each coal was studied. Samples of each coal were shock heated undermore » pressure to simulate coking in the top of a Lurgi gasifier. The resultant cokes were tested for various physical properties and the product yields were determined. Gas release patterns during pressurized pyrolysis were obtained in several instances. The data obtained in this work should provide a valuable data base for future gasifier feedstock evaluation programs.« less

Momentum flux parasitic to free-energy transfer

DOE PAGES

Stoltzfus-Dueck, T.; Scott, B.

2017-05-11

An often-neglected portion of the radialmore » $$\\boldsymbol{E}\\times \\boldsymbol{B}$$ drift is shown to drive an outward flux of co-current momentum when free energy is transferred from the electrostatic potential to ion parallel flows. This symmetry breaking is fully nonlinear, not quasilinear, necessitated simply by free-energy balance in parameter regimes for which significant energy is dissipated via ion parallel flows. The resulting rotation peaking is counter-current and has a scaling and order of magnitude that are comparable with experimental observations. Finally, the residual stress becomes inactive when frequencies are much higher than the ion transit frequency, which may explain the observed relation of density peaking and counter-current rotation peaking in the core.« less

Preparative isolation and purification of three sesquiterpenoid lactones from Eupatorium lindleyanum DC. by high-speed counter-current chromatography.

PubMed

Yan, Guilong; Ji, Lilian; Luo, Yuming; Hu, Yonghong

2012-07-27

A high-speed counter-current chromatography (HSCCC) method was established for the preparative separation of three sesquiterpenoid lactones from Eupatorium lindleyanum DC. The two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:4:2:3, v/v/v/v) was selected. From 540 mg of the n-butanol fraction of Eupatorium lindleyanum DC., 10.8 mg of 3β-hydroxy-8β-[4'-hydroxytigloyloxy]-costunolide, 17.9 mg of eupalinolide A and 19.3 mg of eupalinolide B were obtained in a one-step HSCCC separation, with purities of 91.8%, 97.9% and 97.1%, respectively, as determined by HPLC. Their structures were further identified by ESI-MS and ¹H-NMR.

Effect of magnetic field configuration on the multiply charged ion and plume characteristics in Hall thruster plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Holak; Lim, Youbong; Choe, Wonho, E-mail: wchoe@kaist.ac.kr

2015-04-13

Multiply charged ions and plume characteristics in Hall thruster plasmas are investigated with regard to magnetic field configuration. Differences in the plume shape and the fraction of ions with different charge states are demonstrated by the counter-current and co-current magnetic field configurations, respectively. The significantly larger number of multiply charged and higher charge state ions including Xe{sup 4+} are observed in the co-current configuration than in the counter-current configuration. The large fraction of multiply charged ions and high ion currents in this experiment may be related to the strong electron confinement, which is due to the strong magnetic mirror effectmore » in the co-current magnetic field configuration.« less

Electric field-driven, magnetically-stabilized ferro-emulsion phase contactor

DOEpatents

Scott, T.C.

1990-07-17

Methods and systems are disclosed for interfacial surface area contact between a dispersed phase liquid and a continuous phase liquid in counter-current flow for purposes such as solvent extraction. Initial droplets of a dispersed phase liquid material containing ferromagnetic particles functioning as a packing'' are introduced to a counter-current flow of the continuous phase. A high intensity pulsed electric field is applied so as to shatter the initial droplets into a ferromagnetic emulsion comprising many smaller daughter droplets having a greater combined total surface area than that of the initial droplets in contact with the continuous phase material. A magnetic field is applied to control the position of the ferromagnetic emulsion for enhanced coalescence of the daughter droplets into larger reformed droplets. 2 figs.

Electric field-driven, magnetically-stabilized ferro-emulsion phase contactor

DOEpatents

Scott, Timothy C.

1990-01-01

Methods and systems for interfacial surface area contact between a dispersed phase liquid and a continuous phase liquid in counter-current flow for purposes such as solvent extraction. Initial droplets of a dispersed phase liquid material containing ferromagnetic particles functioning as a "packing" are introduced to a counter-current flow of the continuous phase. A high intensity pulsed electric field is applied so as to shatter the initial droplets into a ferromagnetic emulsion comprising many smaller daughter droplets having a greater combined total surface area than that of the initial droplets in contact with the continuous phase material. A magnetic field is applied to control the position of the ferromagnetic emulsion for enhanced coalescence of the daughter droplets into larger reformed droplets.

Two-step purification of scutellarin from Erigeron breviscapus (vant.) Hand. Mazz. by high-speed counter-current chromatography.

PubMed

Gao, Min; Gu, Ming; Liu, Chun-Zhao

2006-07-11

Scutellarin, a flavone glycoside, popularly applied for the treatment of cardiopathy, has been purified in two-step purification by high-speed counter-current chromatography (HSCCC) from Erigeron breviscapus (vant.) Hand. Mazz. (Deng-zhan-hua in Chinese), a well-known traditional Chinese medicinal plant for heart disease. Two solvent systems, n-hexane-ethyl acetate-methanol-acetic acid-water (1:6:1.5:1:4, v/v/v/v/v) and ethyl acetate-n-butanol-acetonitrile-0.1% HCl (5:2:5:10, v/v/v/v) were used for the two-step purification. The purity of the collected fraction of scutellarin was 95.6%. This study supplies a new alternative method for purification of scutellarin.

Mathematical modelling of particle mixing effect on the combustion of municipal solid wastes in a packed-bed furnace.

PubMed

Yang, Yao Bin; Swithenbank, Jim

2008-01-01

Packed bed combustion is still the most common way to burn municipal solid wastes. In this paper, a dispersion model for particle mixing, mainly caused by the movement of the grate in a moving-burning bed, has been proposed and transport equations for the continuity, momentum, species, and energy conservation are described. Particle-mixing coefficients obtained from model tests range from 2.0x10(-6) to 3.0x10(-5)m2/s. A numerical solution is sought to simulate the combustion behaviour of a full-scale 12-tonne-per-h waste incineration furnace at different levels of bed mixing. It is found that an increase in mixing causes a slight delay in the bed ignition but greatly enhances the combustion processes during the main combustion period in the bed. A medium-level mixing produces a combustion profile that is positioned more at the central part of the combustion chamber, and any leftover combustible gases (mainly CO) enter directly into the most intensive turbulence area created by the opposing secondary-air jets and thus are consumed quickly. Generally, the specific arrangement of the impinging secondary-air jets dumps most of the non-uniformity in temperature and CO into the gas flow coming from the bed-top, while medium-level mixing results in the lowest CO emission at the furnace exit and the highest combustion efficiency in the bed.

[Special beds. Pulmonary therapy system].

PubMed

Calixto Rodríguez, Joaquín; Rodríguez Martínez, Xavier; Marín i Vivó, Gemma; Paunellas Albert, Josep

2008-10-01

To be bedridden reduces one's capacity to move and produces muscular debility that affects the respiratory system leading to a decreased effectiveness in expectoration, the ability to spit up sputum. The pulmonary therapy system integrated in a bed is the result of applying motorized elements to the articulation points of the bad in order to achieve safe positions at therapeutic angles, which improve the breathing-perfusion (blood flow) relationship. This system also makes it possible to apply vibration waves to the patient which favor the elimination of bronchial-pulmonary secretions, the rehabilitation of the bedridden patient and decrease the work load for nursing personnel.

Countercurrent flow afterburner

DOEpatents

Leggett, Ronald L.; Presse, Donald E.; Smith, Carl J.; Teter, Alton R.

1976-01-01

Afterburner apparatus for receiving from an incinerator products of combustion and distributing them through a domed distributor in counterflow manner throughout a housing, in opposition to a stream of combustible gas.

Isolation of four phenolic compounds from Mangifera indica L. flowers by using normal phase combined with elution extrusion two-step high speed countercurrent chromatography.

PubMed

Shaheen, Nusrat; Lu, Yanzhen; Geng, Ping; Shao, Qian; Wei, Yun

2017-03-01

Two-step high speed countercurrent chromatography method, following normal phase and elution-extrusion mode of operation by using selected solvent systems, was introduced for phenolic compounds separation. Phenolic compounds including gallic acid, ethyl gallate, ethyl digallate and ellagic acid were separated from the ethanol extract of mango (Mangifera indica L.) flowers for the first time. In the first step, gallic acid of 3.7mg and ethyl gallate of 3.9mg with the purities of 98.87% and 99.55%, respectively, were isolated by using hexane-ethylacetate-methanol-water (4:6:4:6, v/v) in normal phase high speed countercurrent chromatography from 200mg of crude extract, while ethyl digallate and ellagic acid were collected in the form of mixture fraction. In the second step, further purification of the mixture was carried out with the help of another selected solvent system of dichloromethane-methanol-water (4:3:2, v/v) following elusion-extrusion mode of operation. Ethyl digallate of 3.8mg and ellagic acid of 5.7mg were separated well with high purities of 98.68% and 99.71%, respectively. The separated phenolic compounds were identified and confirmed by HPLC, UPLC-QTOF/ESI-MS, 1 H and 13 C NMR spectrometric analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparative isolation and purification of antioxidative diarylheptanoid derivatives from Alnus japonica by high-speed counter-current chromatography.

PubMed

Lim, Soon Sung; Lee, Min Young; Ahn, Hong Ryul; Choi, Soon Jung; Lee, Jae-Yong; Jung, Sang Hoon

2011-12-01

This study employed the online HPLC-2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS)(+) bioassay to rapidly determine the antioxidant compounds occurring in the crude extract of Alnus japonica. The negative peaks of the ABTS(+) radical scavenging detection system, which indicated the presence of antioxidant activity, were monitored by measuring the decrease in absorbance at 734 nm. The ABTS(+)-based antioxidant activity profile showed that three negative peaks exhibited antioxidant activity. High-speed counter-current chromatography (HSCCC) was used for preparative scale separation of the three active peaks from the extract. The purity of the isolated compounds was analyzed by HPLC and their structures were identified by (1)H- and (13)C-nuclear magnetic resonance spectrometry (NMR), heteronuclear multiple bond correlation (HMBC), and heteronuclear single quantum correlation (HSQC). Two solvent systems composed of n-hexane/ethylacetate/methanol/water (4:6:4:6, v/v) and of ethyl acetate/methanol/water (1:0.1:1, v/v) were performed in high-speed counter-current chromatography. Consequently, a total of 527 mg of hirsutanonol 5-O-β-D-glucopyranoside, 80.04 mg of 3-deoxohirsutenonol 5-O-β-D-glucopyranoside, and 91.0 mg of hirsutenone were obtained with purity of 94.7, 90.5, and 98.6%, respectively. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Purification of monoclonal antibodies from clarified cell culture fluid using Protein A capture continuous countercurrent tangential chromatography

PubMed Central

Dutta, Amit K.; Tran, Travis; Napadensky, Boris; Teella, Achyuta; Brookhart, Gary; Ropp, Philip A.; Zhang, Ada W.; Tustian, Andrew D.; Zydney, Andrew L.; Shinkazh, Oleg

2015-01-01

Recent studies using simple model systems have demonstrated that Continuous Countercurrent Tangential Chromatography (CCTC) has the potential to overcome many of the limitations of conventional Protein A chromatography using packed columns. The objective of this work was to optimize and implement a CCTC system for monoclonal antibody purification from clarified Chinese Hamster Ovary (CHO) cell culture fluid using a commercial Protein A resin. Several improvements were introduced to the previous CCTC system including the use of retentate pumps to maintain stable resin concentrations in the flowing slurry, the elimination of a slurry holding tank to improve productivity, and the introduction of an “after binder” to the binding step to increase antibody recovery. A kinetic binding model was developed to estimate the required residence times in the multi-stage binding step to optimize yield and productivity. Data were obtained by purifying two commercial antibodies from two different manufactures, one with low titer (~0.67 g/L) and one with high titer (~6.9 g/L), demonstrating the versatility of the CCTC system. Host cell protein removal, antibody yields and purities were similar to that obtained with conventional column chromatography; however, the CCTC system showed much higher productivity. These results clearly demonstrate the capabilities of continuous countercurrent tangential chromatography for the commercial purification of monoclonal antibody products. PMID:25747172

Purification of monoclonal antibodies from clarified cell culture fluid using Protein A capture continuous countercurrent tangential chromatography.

PubMed

Dutta, Amit K; Tran, Travis; Napadensky, Boris; Teella, Achyuta; Brookhart, Gary; Ropp, Philip A; Zhang, Ada W; Tustian, Andrew D; Zydney, Andrew L; Shinkazh, Oleg

2015-11-10

Recent studies using simple model systems have demonstrated that continuous countercurrent tangential chromatography (CCTC) has the potential to overcome many of the limitations of conventional Protein A chromatography using packed columns. The objective of this work was to optimize and implement a CCTC system for monoclonal antibody purification from clarified Chinese Hamster Ovary (CHO) cell culture fluid using a commercial Protein A resin. Several improvements were introduced to the previous CCTC system including the use of retentate pumps to maintain stable resin concentrations in the flowing slurry, the elimination of a slurry holding tank to improve productivity, and the introduction of an "after binder" to the binding step to increase antibody recovery. A kinetic binding model was developed to estimate the required residence times in the multi-stage binding step to optimize yield and productivity. Data were obtained by purifying two commercial antibodies from two different manufactures, one with low titer (∼ 0.67 g/L) and one with high titer (∼ 6.9 g/L), demonstrating the versatility of the CCTC system. Host cell protein removal, antibody yields and purities were similar to those obtained with conventional column chromatography; however, the CCTC system showed much higher productivity. These results clearly demonstrate the capabilities of continuous countercurrent tangential chromatography for the commercial purification of monoclonal antibody products. Copyright © 2015 Elsevier B.V. All rights reserved.

Separation of catechin constituents from five tea cultivars using high-speed counter-current chromatography.

PubMed

Kumar, N Savitri; Rajapaksha, Maheshinie

2005-08-12

Catechins were extracted from five different tea (Camellia sinensis L.) cultivars. High-speed counter-current chromatography was found to be an efficient method for the separation of seven catechins from the catechin extracts. High-performance liquid chromatography was used to assess the purity of the catechins isolated. Epigallocatechin gallate (EGCG), epicatechin gallate (ECG) and epigallocatechin (EGC) of high purity (91-99%) were isolated in high yield after a single high-speed counter-current chromatography run. The two-phase solvent mixtures used for the separation of the catechin extracts were hexane:ethyl acetate:methanol:water (1:6:1:6 for TRI 2023); (1:7:1:7 for TRI 2025 and TRI 2043); (1:5:1:5 for TRI 3079) and (1:6.5:1:6.5 for TRI 4006). Fresh tea shoots from the tea cultivar TRI 2023 (150 g) gave 440 mg of 96% pure EGCG while TRI 2025 (235 g) gave 347 mg of 99% pure EGCG and 40 mg of 97% ECG, and TRI 3079 (225 g) gave 432 mg of 97% pure EGCG and 32 mg of 96% pure ECG. Tea cultivar TRI 4006 (160 g) gave EGCG (272 mg, 96% pure) and EGC (104 mg, 90% pure). 1H and 13C NMR chemical shifts for catechin gallate (CG), EGC, ECG, EGCG and epigallocatechin 3,5-di-O-gallate (EGCDG) in CD3OD were also recorded.

Separation and purification of five alkaloids from Aconitum duclouxii by counter-current chromatography.

PubMed

Wang, Yarong; Cai, Shining; Chen, Yang; Deng, Liang; Zhou, Xumei; Liu, Jia; Xu, Xin; Xia, Qiang; Lin, Mao; Zhang, Jili; Huang, Weili; Wang, Wenjun; Xiang, Canhui; Cui, Guozhen; Du, Lianfeng; He, Huan; Qi, Baohui

2015-07-01

C19 -diterpenoid alkaloids are the main components of Aconitum duclouxii Levl. The process of separation and purification of these compounds in previous studies was tedious and time consuming, requiring multiple chromatographic steps, thus resulted in low recovery and high cost. In the present work, five C19 -diterpenoid alkaloids, namely, benzoylaconine (1), N-deethylaconitine (2), aconitine (3), deoxyaconitine (4), and ducloudine A (5), were efficiently prepared from A. duclouxii Levl (Aconitum L.) by ethyl acetate extraction followed with counter-current chromatography. In the process of separation, the critical conditions of counter-current chromatography were optimized. The two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water/NH3 ·H2 O (25%) (1:1:1:1:0.1, v/v) was selected and 148.2 mg of 1, 24.1 mg of 2, 250.6 mg of 3, 73.9 mg of 4, and 31.4 mg of 5 were obtained from 1 g total Aconitum alkaloids extract, respectively, in a single run within 4 h. Their purities were found to be 98.4, 97.2, 98.2, 96.8, and 96.6%, respectively, by ultra-high performance liquid chromatography analysis. The presented separation and purification method was simple, fast, and efficient, and the obtained highly pure alkaloids are suitable for biochemical and toxicological investigation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparative separation of bioactive compounds from essential oil of Flaveria bidentis (L.) Kuntze using steam distillation extraction and one step high-speed counter-current chromatography.

PubMed

Wei, Yun; Du, Jilin; Lu, Yuanyuan

2012-10-01

In order to utilize and control the invasive weed, bioactive compounds from essential oil of Flaveria bidentis (L.) Kuntze were studied. Steam distillation extraction and one step high-speed counter-current chromatography were applied to separate and purify the caryophyllene oxide, 7,11-dimethyl-3-methylene-1,6,10-dodecatriene, and caryophyllene from essential oil of Flaveria bidentis (L.) Kuntze. The two-phase solvent system containing n-hexane/acetonitrile/ethanol (5:4:3, v/v/v) was selected for the one step separation mode according to the partition coefficient values (K) of the target compounds and the separation factor (α). The purity of each isolated fraction after a single high-speed counter-current chromatography run was determined by high performance liquid chromatography. A 3.2 mg of caryophyllene oxide at a purity of 92.6%, 10.4 mg of 7,11-dimethyl-3-methylene-1,6,10-dodecatriene at a purity of 99.1% and 5.7 mg of caryophyllene at a purity of 98.8% were obtained from 200 mg essential oil of Flaveria bidentis (L.) Kuntze. The chemical structures of these components were identified by GC-MS, (1) H-NMR, and (13) C-NMR. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Hydrologic characteristics and possible effects of surface mining in the northwestern part of West Branch Antelope Creek basin, Mercer County, North Dakota

USGS Publications Warehouse

Crawley, Mark E.; Emerson, Douglas G.

1981-01-01

Lignite beds and abundant discontinuous sandstone beds of the Paleocene Sentinel Butte Member of the Fort Union Formation and sand and gravel beds in the Quarternary glaciofluvial deposits (Antelope Creek aquifer) are the most important aquifers for domestic and livestock water supplies in the West Branch Antelope Creek basin. In the Beulah-Zap lignite, ground water moves from highland area in the west toward the Antelope Creek aquifer. Water levels in the basal Sentinel Butte sandstone appear to be controlled by the level of Lake Sakakawea. In the glaciofluvial deposits of the Antelope Creek aquifer water moves from a ground-water divide northwestward to Lake Sakakawea and southeastward toward the Knife River. Large water-level declines in wells completed in the lignite and shallower aquifers could be expected with mining. The effects probably would be limited to within 1 to 2 miles of an active mine. Surface-runoff duration could be altered by increased infiltration and retention in the reclaimed are and possible temporal extension of base flow could occur. Shallow ground water beneath mine sites would be expected to increase in dissolved solids and locally to contain large sodium and sulfate concentrations. In some locations movement of poor quality water toward the Antelope Creek aquifer would be expected. (USGS)

Pyroclast/snow interactions and thermally driven slurry formation. Part 1: Theory for monodisperse grain beds

USGS Publications Warehouse

Walder, J.S.

2000-01-01

Lahars are often produced as pyroclastic flows move over snow. This phenomenon involves a complicated interplay of mechanical and thermal processes that need to be separated to get at the fundamental physics. The thermal physics of pyroclast/snow interactions form the focus of this paper. A theoretical model is developed of heat- and mass transfer at the interface between a layer of uniformly sized pyroclasts and an underlying bed of snow, for the case in which there is no relative shear motion between pyroclasts and snow. A microscale view of the interface is required to properly specify boundary conditions. The physical model leads to the prediction that the upward flux of water vapor - which depends upon emplacement temperature, pyroclast grain size, pyroclast-layer thickness, and snow permeability - is sometimes sufficient to fluidize the pyroclasts. Uniform fluidization is usually unstable to bubble formation, which leads to vigorous convection of the pyroclasts themselves. Thus, predicted threshold conditions for fluidization are tantamount to predicted thresholds for particle convection. Such predictions are quantitatively in good agreement with results of experiments described in part 2 of this paper. Because particle convection commonly causes scour of the snow bed and transformation of the pyroclast layer to a slurry, there exists a 'thermal scour' process for generating lahars from pyroclastic flows moving over snow regardless of the possible role of mechanical scour.

Paired Straight Hearth Furnace - Transformational Ironmaking Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Wei-Kao; Debski, Paul

2014-11-19

The U. S. steel industry has reduced its energy intensity per ton of steel shipped by 33% since 1990. However, further significant gains in energy efficiency will require the development of new, transformational iron and steelmaking processes. The Paired Straight Hearth Furnace (PSH) process is an emerging alternative high productivity, direct reduced iron (DRI) technology that may achieve very low fuel rates and has the potential to replace blast furnace ironmaking. The PSH furnace can operate independently or may be coupled with other melting technologies to produce liquid hot metal that is both similar to blast furnace iron and suitablemore » as a feedstock for basic oxygen steelmaking furnaces. The PSH process uses non-metallurgical coal as a reductant to convert iron oxides such as iron ore and steelmaking by-product oxides to DRI pellets. In this process, a multi-layer, nominally 120mm tall bed of composite “green balls” made from oxide, coal and binder is built up and contained within a moving refractory hearth. The pellet bed absorbs radiant heat energy during exposure to the high temperature interior refractory surfaces of the PSH while generating a strongly reducing gas atmosphere in the bed that yields a highly metalized DRI product. The PSH concept has been well tested in static hearth experiments. A moving bed design is being developed. The process developers believe that if successful, the PSH process has the potential to replace blast furnaces and coke ovens at a fraction of the operating and capital cost while using about 30% less energy relative to current blast furnace technology. DRI output could also feed electric arc furnaces (EAFs) by displacing a portion of the scrap charge.« less

Unmanned Instrument Platform for Undersea Exploration

NASA Technical Reports Server (NTRS)

Paine, G.; Hansen, G. R.; Gulizia, R. W.; Paluzzi, P.

1984-01-01

Instruments accommodated on moving underwater platform. Towable underwater platform 3.2 meters long, 1.2 meters wide, 1.4 meters high and has mass of about 1,250 kilogram. Platform remotely operated and unmanned. Serves as test bed for development of ocean-measuring instruments and sonars at depths to 20,000 feet.

Tethered acoustic doppler current profiler platforms for measuring streamflow

USGS Publications Warehouse

Rehmel, Michael S.; Stewart, James A.; Morlock, Scott E.

2003-01-01

A tethered-platform design with a trimaran hull and 900-megahertz radio modems is now commercially available. Continued field use has resulted in U.S. Geological Survey procedures for making tethered-platform discharge measurements, including methods for tethered-boat deployment, moving-bed tests, and measurement of edge distances.

Isolation and purification of orientin and vitexin from Trollius chinensis Bunge by high-speed counter-current chromatography.

PubMed

Yu, Xiao-Xue; Huang, Jie-Yun; Xu, Dan; Xie, Zhi-Yong; Xie, Zhi-Sheng; Xu, Xin-Jun

2014-01-01

Orientin and vitexin are the two main bioactive compounds in Trollius chinensis Bunge. In this study, a rapid method was established for the isolation and purification of orientin and vitexin from T. chinensis Bunge using high-speed counter-current chromatography in one step, with a solvent system of ethyl acetate-ethanol-water (4:1:5, v/v/v). A total of 9.8 mg orientin and 2.1 mg vitexin were obtained from 100 mg of the ethyl acetate extract, with purities of 99.2% and 96.0%, respectively. Their structures were identified by UV, MS and NMR. The method was efficient and convenient, which could be used for the preparative separation of orientin and vitexin from T. chinensis Bunge.

Preparative isolation and purification of harpagoside and angroside C from the root of Scrophularia ningpoensis Hemsley by high-speed counter-current chromatography.

PubMed

Tian, Jinfeng; Ye, Xiaoli; Shang, Yuanhong; Deng, Yafei; He, Kai; Li, Xuegang

2012-10-01

In this study, the bioactive component harpagoside and angroside C in the root of Scrophularia ningpoensis Hemsley was simultaneously separated by high-speed counter-current chromatography (HSCCC). A two-phase solvent system containing chloroform/n-butanol/methanol/water (4:1:3:2, v/v/v/v) was selected following consideration of the partition coefficient of the target compound. The crude extract (200 mg) was loaded onto a 280-mL HSCCC column and yielded 22 mg harpagoside and 31 mg angroside C with the purity of higher than 98 and 98.5%, respectively. It is feasible to isolate active compounds harpagoside and angroside C from S. ningpoensis using HSCCC. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation and purification of astaxanthin from Phaffia rhodozyma by preparative high-speed counter-current chromatography.

PubMed

Du, Xiping; Dong, Congcong; Wang, Kai; Jiang, Zedong; Chen, Yanhong; Yang, Yuanfan; Chen, Feng; Ni, Hui

2016-09-01

An effective high-speed counter-current chromatography (HSCCC) method was established for the preparative isolation and purification of astaxanthin from Phaffia rhodozyma. With a two-phase solvent system composed of n-hexane-acetone-ethanol-water (1:1:1:1, v/v/v/v), 100mg crude extract of P. rhodozyma was separated to yield 20.6mg of astaxanthin at 92.0% purity. By further one step silica gel column chromatography, the purity reached 99.0%. The chemical structure of astaxanthin was confirmed by thin layer chromatography (TLC), UV spectroscopy scanning, high performance liquid chromatography with a ZORBAX SB-C18 column and a Waters Nova-pak C18 column, and ESI/MS/MS. Copyright © 2016 Elsevier B.V. All rights reserved.

Method for enhancing selectivity and recovery in the fractional flotation of particles in a flotation column

DOEpatents

Klunder, Edgar B [Bethel Park, PA

2011-08-09

The method relates to particle separation from a feed stream. The feed stream is injected directly into the froth zone of a vertical flotation column in the presence of a counter-current reflux stream. A froth breaker generates a reflux stream and a concentrate stream, and the reflux stream is injected into the froth zone to mix with the interstitial liquid between bubbles in the froth zone. Counter-current flow between the plurality of bubbles and the interstitial liquid facilitates the attachment of higher hydrophobicity particles to bubble surfaces as lower hydrophobicity particles detach. The height of the feed stream injection and the reflux ratio may be varied in order to optimize the concentrate or tailing stream recoveries desired based on existing operating conditions.

Sediment supply controls equilibrium channel geometry in gravel rivers

PubMed Central

Finnegan, Noah J.; Willenbring, Jane K.

2017-01-01

In many gravel-bedded rivers, floods that fill the channel banks create just enough shear stress to move the median-sized gravel particles on the bed surface (D50). Because this observation is common and is supported by theory, the coincidence of bankfull flow and the incipient motion of D50 has become a commonly used assumption. However, not all natural gravel channels actually conform to this simple relationship; some channels maintain bankfull stresses far in excess of the critical stress required to initiate sediment transport. We use a database of >300 gravel-bedded rivers and >600 10Be-derived erosion rates from across North America to explore the hypothesis that sediment supply drives the magnitude of bankfull shear stress relative to the critical stress required to mobilize the median bed surface grain size (τbf*/τc*). We find that τbf*/τc* is significantly higher in West Coast river reaches (2.35, n = 96) than in river reaches elsewhere on the continent (1.03, n = 245). This pattern parallels patterns in erosion rates (and hence sediment supplies). Supporting our hypothesis, we find a significant correlation between upstream erosion rate and local τbf*/τc* at sites where this comparison is possible. Our analysis reveals a decrease in bed surface armoring with increasing τbf*/τc*, suggesting channels accommodate changes in sediment supply through adjustments in bed surface grain size, as also shown through numerical modeling. Our findings demonstrate that sediment supply is encoded in the bankfull hydraulic geometry of gravel bedded channels through its control on bed surface grain size. PMID:28289212

Flume Experiments on the Influence of Salmon Spawning Density on Grain Stability and Bedload Transport in Gravel-bed Streams

NASA Astrophysics Data System (ADS)

Buxton, T. H.

2015-12-01

Salmon spawning in streams involves the female salmon digging a pit in the bed where she deposits eggs for fertilization before covering them with gravel excavated from the next pit upstream. Sequences of pit excavation and filling winnow fines, loosen sediment, and move bed material into a tailspill mound resembling the shape of a dune. Research suggests salmonid nests (redds) destabilize streambeds by reducing friction between loosened grains and converging flow that elevates shear stress on redd topography. However, bed stability may be enhanced by form drag from redds in clusters that lower shear stress on the granular bed, but this effect will vary with the proportion of the bed surface that is occupied by redds (P). I used simulated redds and water-worked ("unspawned") beds in a laboratory flume to evaluate these competing influences on grain stability and bedload transport rates with P=0.12, 0.34, and 0.41. Results indicate that competence (largest-grain) and reference transport rate estimates of critical conditions for particle entrainment inversely relate to P. Bedload transport increased as exponential functions of P and excess boundary shear stress. Therefore, redd form drag did not overcome the destabilizing effects of spawning. Instead, grain mobility and bedload transport increased with P because larger areas of the bed were composed of relatively loose, unstable grains and redd topography that experienced elevated shear stress. Consequently, the presence of redds in fish-bearing streams likely reduces the effects of sedimentation from landscape disturbance on stream habitats that salmon use for reproduction.

Intrahospital transfers and adverse patient outcomes: An analysis of administrative health data.

PubMed

Blay, Nicole; Roche, Michael; Duffield, Christine; Xu, Xiaoyue

2017-12-01

To determine whether there was an association between intra-hospital transfers and adverse outcomes. Transfers between clinical units and between beds on the same unit are routine aspects of an episode of care in acute hospitals. The rate of these transfers per episode has increased in response to high occupancy levels, a decline in bed numbers, and increased demand for hospital services. The impact of the number of transfers between both wards and beds on patient outcomes is not widely explored. Retrospective cross sectional design using hospital administrative data. Data were extracted from existing hospital administrative datasets for one large metropolitan hospital for the financial year 2008-09 in Australia (n = 14,133). Descriptive analyses and logistic regression models were developed for each of 3 selected patient outcomes. Nearly one-tenth of patients (9.2%) experienced a fall with injury, 3.8% of surgical patients a wound infection and 0.1% a complication from medication errors. For each bed or ward transfer, the odds of falls and wound infections increased. Medication errors were not associated with either bed or ward moves. Hospitals should minimise the number of bed and ward transfers per episode of care in order to reduce the likelihood of adverse patient outcomes. Current bed management policies and practices should be evaluated and further refined to address this need. Additional strategies include improving coordination and communication during and after transfer. Nurses must consider the potential cost of intrahospital transfers on patients, length of stay and bed availability. © 2017 John Wiley & Sons Ltd.

Experimental study of heat and mass transfer in a buoyant countercurrent exchange flow

NASA Astrophysics Data System (ADS)

Conover, Timothy Allan

Buoyant Countercurrent Exchange Flow occurs in a vertical vent through which two miscible fluids communicate, the higher-density fluid, residing above the lower-density fluid, separated by the vented partition. The buoyancy- driven zero net volumetric flow through the vent transports any passive scalars, such as heat and toxic fumes, between the two compartments as the fluids seek thermodynamic and gravitational equilibrium. The plume rising from the vent into the top compartment resembles a pool fire plume. In some circumstances both countercurrent flows and pool fires can ``puff'' periodically, with distinct frequencies. One experimental test section containing fresh water in the top compartment and brine (NaCl solution) in the bottom compartment provided a convenient, idealized flow for study. This brine flow decayed in time as the concentrations approached equilibrium. A second test section contained fresh water that was cooled by heat exchangers above and heated by electrical elements below and operated steadily, allowing more time for data acquisition. Brine transport was reduced to a buoyancy- scaled flow coefficient, Q*, and heat transfer was reduced to an analogous coefficient, H*. Results for vent diameter D = 5.08 cm were consistent between test sections and with the literature. Some results for D = 2.54 cm were inconsistent, suggesting viscosity and/or molecular diffusion of heat become important at smaller scales. Laser Doppler Velocimetry was used to measure velocity fields in both test sections, and in thermal flow a small thermocouple measured temperature simultaneously with velocity. Measurement fields were restricted to the plume base region, above the vent proper. In baseline periodic flow, instantaneous velocity and temperature were ensemble averaged, producing a movie of the average variation of each measure during a puffing flow cycle. The temperature movie revealed the previously unknown cold core of the puff during its early development. The renewal-length model for puffing frequency of pool fire plumes was extended to puffing countercurrent flows by estimating inflow dilution. Puffing frequencies at several conditions were reduced to Strouhal number based on dilute plume density. Results for D = 5.08 cm compared favorably to published measurements of puffing pool fires, suggesting that the two different flows obey the same periodic dynamic process.

The underlying reasons for very high levels of bed net use, and higher malaria infection prevalence among bed net users than non-users in the Tanzanian city of Dar es Salaam: a qualitative study.

PubMed

Msellemu, Daniel; Shemdoe, Aloysia; Makungu, Christina; Mlacha, Yeromini; Kannady, Khadija; Dongus, Stefan; Killeen, Gerry F; Dillip, Angel

2017-10-23

Bed nets reduce malaria-related illness and deaths, by forming a protective barrier around people sleeping under them. When impregnated with long-lasting insecticide formulations they also repel or kill mosquitoes attempting to feed upon sleeping humans, and can even suppress entire populations of malaria vectors that feed predominantly upon humans. Nevertheless, an epidemiological study in 2012 demonstrated higher malaria prevalence among bed net users than non-users in urban Dar es Salaam, Tanzania. Focus group discussions were conducted with women from four selected wards of Dar es Salaam city, focusing on four major themes relating to bed net use behaviours: (1) reasons for bed net use, (2) reasons for not using bed nets, (3) stimuli or reminders for people to use a bed net (4) perceived reasons for catching malaria while using a bed net. An analytical method by framework grouping of relevant themes was used address key issues of relevance to the study objectives. Codes were reviewed and grouped into categories and themes. All groups said the main reason for bed net use was protection against malaria. Houses with well-screened windows, with doors that shut properly, and that use insecticidal sprays against mosquitoes, were said not to use bed nets, while frequent attacks from malaria was the main stimulus for people to use bed nets. Various reasons were mentioned as potential reasons that compromise bed net efficacy, the most common of which were: (1) bed net sharing by two or more people, especially if one occupant tends to come to bed late at night, and does not tuck in the net 71%; (2) one person shares the bed but does not use the net, moving it away from the side on which s/he sleeps 68%; (3) ineffective usage habits, called ulalavi, in which a sprawling sleeper either touches the net while sleeping up against it or leaves a limb hanging outside of it 68%. Less common reasons mentioned included: (1) Small bed nets which become un-tucked at night (31%); (2) Bed nets with holes large enough to allow mosquitoes to pass (28%); and (3) Going to bed late after already being bitten outdoors (24%). Behaviours associated with bed net use like; bed sharing, bed net non compliant-bedfellow, sleeping pattern like ulalavi and some physical bed net attributes compromise its effectiveness and supposedly increase of malaria infection to bed net users. While some well-screened houses looked to instigate low malaria prevalence to non-bed net users.

Clinical physiology of bed rest

NASA Technical Reports Server (NTRS)

Greenleaf, John E.

1993-01-01

Maintenance of optimal health in humans requires the proper balance between exercise, rest, and sleep as well as time in the upright position. About one-third of a lifetime is spent sleeping; and it is no coincidence that sleeping is performed in the horizontal position, the position in which gravitational influence on the body is minimal. Although enforced bed rest is necessary for the treatment of some ailments, in some cases it has probably been used unwisely. In addition to the lower hydrostatic pressure with the normally dependent regions of the cardiovascular system, body fuid compartments during bed rest in the horizontal body position, and virtual elimination of compression on the long bones of the skeletal system during bed rest (hypogravia), there is often reduction in energy metabolism due to the relative confinement (hypodynamia) and alteration of ambulatory circadian variations in metabolism, body temperature, and many hormonal systems. If patients are also moved to unfamiliar surroundings, they probably experience some feelings of anxiety and some sociopsychological problems. Adaptive physiological responses during bed rest are normal for that environment. They are attempts by the body to reduce unnecessary energy expenditure, to optimize its function, and to enhance its survival potential. Many of the deconditioning responses begin within the first day or two of bed rest; these early responses have prompted physicians to insist upon early resumption of the upright posture and ambulation of bedridden patients.

Assessing the use of an infrared spectrum hyperpixel array imager to measure temperature during additive and subtractive manufacturing

NASA Astrophysics Data System (ADS)

Whitenton, Eric; Heigel, Jarred; Lane, Brandon; Moylan, Shawn

2016-05-01

Accurate non-contact temperature measurement is important to optimize manufacturing processes. This applies to both additive (3D printing) and subtractive (material removal by machining) manufacturing. Performing accurate single wavelength thermography suffers numerous challenges. A potential alternative is hyperpixel array hyperspectral imaging. Focusing on metals, this paper discusses issues involved such as unknown or changing emissivity, inaccurate greybody assumptions, motion blur, and size of source effects. The algorithm which converts measured thermal spectra to emissivity and temperature uses a customized multistep non-linear equation solver to determine the best-fit emission curve. Emissivity dependence on wavelength may be assumed uniform or have a relationship typical for metals. The custom software displays residuals for intensity, temperature, and emissivity to gauge the correctness of the greybody assumption. Initial results are shown from a laser powder-bed fusion additive process, as well as a machining process. In addition, the effects of motion blur are analyzed, which occurs in both additive and subtractive manufacturing processes. In a laser powder-bed fusion additive process, the scanning laser causes the melt pool to move rapidly, causing a motion blur-like effect. In machining, measuring temperature of the rapidly moving chip is a desirable goal to develop and validate simulations of the cutting process. A moving slit target is imaged to characterize how the measured temperature values are affected by motion of a measured target.

Researchers evaluate low-energy recirculating system for inland production of marine finfish juveniles

USDA-ARS?s Scientific Manuscript database

The low-energy recirculating aquaculture system consists of nine separate modules which utilize the double drain fish culture tank paired to a moving bed biofilter. The nine fiberglass tanks are five feet in diameter and normal water depth is about three feet for a total tank volume of approximately...

Lateral and vertical channel movement and potential for bed-material movement on the Madison River downstream from Earthquake Lake, Montana

USGS Publications Warehouse

Chase, Katherine J.; McCarthy, Peter M.

2012-01-01

The 1959 Hebgen Lake earthquake caused a massive landslide (Madison Slide) that dammed the Madison River and formed Earthquake Lake. The U.S. Army Corps of Engineers excavated a spillway through the Madison Slide to permit outflow from Earthquake Lake. In June 1970, high streamflows on the Madison River severely eroded the spillway channel and damaged the roadway embankment along U.S. Highway 287 downstream from the Madison Slide. Investigations undertaken following the 1970 flood events concluded that substantial erosion through and downstream from the spillway could be expected for streamflows greater than 3,500 cubic feet per second (ft3/s). Accordingly, the owners of Hebgen Dam, upstream from Earthquake Lake, have tried to manage releases from Hebgen Lake to prevent streamflows from exceeding 3,500 ft3/s measured at the U.S. Geological Survey (USGS) gaging station 0638800 Madison River at Kirby Ranch, near Cameron, Montana. Management of flow releases from Hebgen Lake to avoid exceeding the threshold streamflow at USGS gaging station 06038800 is difficult, and has been questioned for two reasons. First, no road damage was reported downstream from the Earthquake Lake outlet in 1993, 1996, and 1997 when streamflows exceeded the 3,500-ft3/s threshold. Second, the 3,500-ft3/s threshold generally precludes releases of higher flows that could be beneficial to the blue-ribbon trout fishery downstream in the Madison River. In response to concerns about minimizing streamflow downstream from Earthquake Lake and the possible armoring of the spillway, the USGS, in cooperation with the Madison River Fisheries Technical Advisory Committee (MADTAC; Bureau of Land Management; Montana Department of Environmental Quality; Montana Fish, Wildlife and Parks; PPL-Montana; U.S. Department of Agriculture Forest Service - Gallatin National Forest; and U.S. Fish and Wildlife Service), conducted a study to determine movement of the Madison River channel downstream from Earthquake Lake and to investigate the potential for bed material movement along the same reach. The purpose of this report is to present information about the lateral and vertical movement of the Madison River from 1970 to 2006 for a 1-mile reach downstream from Earthquake Lake and for Raynolds Pass Bridge, and to provide an analysis of the potential for bed-material movement so that MADTAC can evaluate the applicability of the previously determined threshold streamflow for initiation of damaging erosion. As part of this study channel cross sections originally surveyed by the USGS in 1971 were resurveyed in 2006. Incremental channel-movement distances were determined by comparing the stream centerlines from 14 aerial photographs taken between 1970 and 2006. Depths of channel incision and aggregation were determined by comparing the 2006 and 1971 cross-section and water-surface data. Particle sizes of bed and bank materials were measured in 2006 and 2008 using the pebble-count method and sieve analyses. A one-dimensional hydraulic-flow model (HEC-RAS) was used to calculate mean boundary-shear stresses for various streamflows; these calculated boundary-shear stresses were compared to calculated critical-shear stresses for the bed materials to determine the potential for bed-material movement. A comparison of lateral channel movement distances with annual peak streamflows shows that streamflows higher than the 3,500-ft3/s threshold were followed by lateral channel movement except from 1991 to 1992 and possibly from 1996 to 1997. However, it was not possible to discern whether the channel moved gradually or suddenly, or in response to one peak flow, to several peak flows, or to sustained flows. The channel moved between 2002 and 2005 even when streamflows were less than the threshold streamflow of 3,500 ft3/s. Comparisons of cross sections and aerial photographs show that the channel has moved laterally and incised and aggraded to varying degrees. The channel has developed meander bends and has incised as much as 5–12 feet (ft) through the upstream part of the Madison Slide (cross sections 1400–800). Near cross section 800, the stream has eroded into the steep right bank between the stream and the road where fill was mechanically placed after 1970. Channel movement also was noted downstream from the Madison Slide. Near Raynolds Pass Bridge, about 3 miles (mi) downstream from Earthquake Lake, elevations across the channel have changed by -1.4 ft to +1.9 ft, but these changes were local in nature and could represent a few rocks or depressions in the bed. Overall, it does not appear that the materials eroded from the Madison Slide are causing aggradation in the subreach near the Raynolds Pass Bridge. Comparisons of critical shear stresses to mean boundary-shear stresses indicate that the D50 particle sizes (median size) along the right side of the bed between cross sections 400 and 500 and along the right side of the bed between cross sections 1300 and 1400 could move at the threshold streamflow. In contrast, most of the D84 particle sizes at those two locations probably will not move at the threshold streamflow. This lack of movement for the larger particles at the threshold streamflow could lead to further armoring of the bed as the D50 and smaller-sized particles are removed from the bed and transported downstream. The Shields parameter values from 0.04 to 0.08 that were used to calculate critical shear stresses could be conservative for a high-gradient stream such as the Madison. A higher, less conservative, Shields parameter would result in higher critical shear stresses, meaning that higher streamflows would be required to move material than those reported herein. In addition, because materials in the channel thalweg are exposed to higher boundary-shear stresses than the materials along the sides of the channel, larger, more erosion-resistant materials likely exist in the deeper parts of the channel where high-flow depths and velocities prevented sediment sampling. Movement of these materials might require higher critical shear stresses than estimated in this report. Characterization of sediment sizes in the center of the stream and observation of bed-material movement for a range of streamflows could provide information to help refine the Shields parameter and critical-shear stress estimates for bed materials in the Madison River downstream from Earthquake Lake. Furthermore, resurveying cross sections and water-surface elevations more frequently (either annually or after high streamflows) could better define the relation between streamflow and lateral and vertical channel movement.

Treatment of petroleum refinery wastewater using a sequential anaerobic-aerobic moving-bed biofilm reactor system based on suspended ceramsite.

PubMed

Lu, Mang; Gu, Li-Peng; Xu, Wen-Hao

2013-01-01

In this study, a novel suspended ceramsite was prepared, which has high strength, optimum density (close to water), and high porosity. The ceramsite was used to feed a moving-bed biofilm reactor (MBBR) system with an anaerobic-aerobic (A/O) arrangement to treat petroleum refinery wastewater for simultaneous removal of chemical oxygen demand (COD) and ammonium. The hydraulic retention time (HRT) of the anaerobic-aerobic MBBR system was varied from 72 to 18 h. The anaerobic-aerobic system had a strong tolerance to shock loading. Compared with the professional emission standard of China, the effluent concentrations of COD and NH3-N in the system could satisfy grade I at HRTs of 72 and 36 h, and grade II at HRT of 18 h. The average sludge yield of the anaerobic reactor was estimated to be 0.0575 g suspended solid/g CODremoved. This work demonstrated that the anaerobic-aerobic MBBR system using the suspended ceramsite as bio-carrier could be applied to achieving high wastewater treatment efficiency.

Phenol removal performance and microbial community shift during pH shock in a moving bed biofilm reactor (MBBR).

PubMed

Zhou, Hao; Wang, Guochen; Wu, Minghuo; Xu, Weiping; Zhang, Xuwang; Liu, Lifen

2018-06-05

A moving bed biofilm reactor (MBBR) effectively removes pollutants and even runs under extreme conditions. However, the pH shock resistance of a biofilm in MBBRs has been rarely reported. In this study, simulated phenol wastewater with acidic shock (pH 7.5-3.0) was used. In the pH shock phase, the phenol and COD removal efficiencies initially decreased and gradually increased to more than 90%. Microscopic studies showed that the superficial biofilm was mainly composed of fungi (yeasts) in the acidic pH shock phase. The microbial community composition in the acidic pH shock phase was significantly different from those in other phases. Firmicutes and Ascomycota were the dominant bacterial and fungal phyla in this stage, respectively. 16S rRNA gene-based functional annotation indicated that functional profiles related to aromatic compound degradation existed in all of the stages. Therefore, MBBRs show potential for the treatment of phenolic wastewater exposed to pH shock. Copyright © 2018 Elsevier B.V. All rights reserved.

Evaluation of micropollutant removal and fouling reduction in a hybrid moving bed biofilm reactor-membrane bioreactor system.

PubMed

Luo, Yunlong; Jiang, Qi; Ngo, Huu H; Nghiem, Long D; Hai, Faisal I; Price, William E; Wang, Jie; Guo, Wenshan

2015-09-01

A hybrid moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) system and a conventional membrane bioreactor (CMBR) were compared in terms of micropollutant removal efficiency and membrane fouling propensity. The results show that the hybrid MBBR-MBR system could effectively remove most of the selected micropollutants. By contrast, the CMBR system showed lower removals of ketoprofen, carbamazepine, primidone, bisphenol A and estriol by 16.2%, 30.1%, 31.9%, 34.5%, and 39.9%, respectively. Mass balance calculations suggest that biological degradation was the primary removal mechanism in the MBBR-MBR system. During operation, the MBBR-MBR system exhibited significantly slower fouling development as compared to the CMBR system, which could be ascribed to the wide disparity in the soluble microbial products (SMP) levels between MBBR-MBR (4.02-6.32 mg/L) and CMBR (21.78 and 33.04 mg/L). It is evident that adding an MBBR process prior to MBR treatment can not only enhance micropollutant elimination but also mitigate membrane fouling. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of kenaf fibers as moving bed biofilm carriers in algal membrane photobioreactor.

PubMed

Derakhshan, Zahra; Mahvi, Amir Hossein; Ehrampoush, Mohammad Hassan; Ghaneian, Mohammad Taghi; Yousefinejad, Saeed; Faramarzian, Mohammad; Mazloomi, Seyed Mohammad; Dehghani, Mansooreh; Fallahzadeh, Hossein

2018-05-15

In this lab-scale study, the feasibility of using kenaf fibers as moving bed biofilm carriers in hybrid microalgal membrane photobioreactors (HMPBR) in organic matter and atrazine elimination from real secondary effluent was evaluated. For evaluating the kinetics of biofilm substrate consumption, an experimental model was proposed. Inoculation of wastewater samples with free carriers resulted in the greater removal of target pollutants. Removal efficiency of atrazine and chemical oxygen demand (COD) increased to 27% and 16%, with respect to the control, respectively. The total biomass accumulation in HMPBR exceeded 5g/L, and the microalgae tended to aggregate and attached to biofilm carriers. The removal efficiency of HMPBR improved significantly via inoculation of kenaf fiber carriers with bioremediation microalgal strains (p < 0.01). A lower stabilization ratio (VSS/TSS) was also recorded. The biomass in HMPBR included more lipids and carbohydrates. The results revealed that kenaf fibers could improve and upgrade the biological activity of different wastewater treatment applications, considering the great potential of biofilm carriers and their effluent quality. Copyright © 2018 Elsevier Inc. All rights reserved.

Improvement of poly-γ-glutamic acid biosynthesis in a moving bed biofilm reactor by Bacillus subtilis NX-2.

PubMed

Jiang, Yongxiang; Tang, Bao; Xu, Zongqi; Liu, Kun; Xu, Zheng; Feng, Xiaohai; Xu, Hong

2016-10-01

The production of poly-γ-glutamic acid (γ-PGA) by Bacillus subtilis NX-2 using a moving bed biofilm reactor (MBBR) system was tested for the first time in this study. Polypropylene TL-2 was chosen as a suitable carrier, and γ-PGA concentration of 42.7±0.86g/L and productivity of 0.59±0.06g/(Lh) were obtained in batch fermentation. After application of the strategy of dissolved oxygen (DO)-stat feeding, higher γ-PGA concentration and productivity were achieved than with glucose feedback feeding. Finally, the repeated fed-batch cultures implemented in the MBBR system showed high stability, and the maximal γ-PGA concentration and productivity of 74.2g/L and 1.24g/(Lh) were achieved, respectively. In addition, the promotion of oxygen transfer by an MBBR carrier was well explained by a computational fluid dynamics (CFD) simulation. These results suggest that an MBBR system could be applied to large-scale γ-PGA production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Isolation and metagenomic characterization of bacteria associated with calcium carbonate and struvite precipitation in a pure moving bed biofilm reactor-membrane bioreactor.

PubMed

Gonzalez-Martinez, A; Leyva-Díaz, J C; Rodriguez-Sanchez, A; Muñoz-Palazon, B; Rivadeneyra, A; Poyatos, J M; Rivadeneyra, M A; Martinez-Toledo, M V

2015-01-01

A bench-scale pure moving bed bioreactor-membrane bioreactor (MBBR-MBR) used for the treatment of urban wastewater was analyzed for the identification of bacterial strains with the potential capacity for calcium carbonate and struvite biomineral formation. Isolation of mineral-forming strains on calcium carbonate and struvite media revealed six major colonies with a carbonate or struvite precipitation capacity in the biofouling on the membrane surface and showed that heterotrophic bacteria with the ability to precipitate calcium carbonate and struvite constituted ~7.5% of the total platable bacteria. These belonged to the genera Lysinibacillus, Trichococcus, Comamomas and Bacillus. Pyrosequencing analysis of the microbial communities in the suspended cells and membrane biofouling showed a high degree of similarity in all the samples collected with respect to bacterial assemblage. The study of operational taxonomic units (OTUs) identified through pyrosequencing suggested that ~21% of the total bacterial community identified in the biofouling could potentially form calcium carbonate or struvite crystals in the pure MBBR-MBR system used for the treatment of urban wastewater.

Bed load tracer mobility in a mixed bedrock/alluvial channel

NASA Astrophysics Data System (ADS)

Ferguson, R. I.; Sharma, B. P.; Hodge, R. A.; Hardy, R. J.; Warburton, J.

2017-04-01

The presence of bare or partially covered rock in an otherwise alluvial river implies a downstream change in transport capacity relative to supply. Field investigations of this change and what causes it are lacking. We used two sets of magnet-tagged tracer clasts to investigate bed load transport during the same sequence of floods in fully alluvial, bare rock, and partial-cover reaches of an upland stream. High-flow shear stresses in different reaches were calculated by using stage loggers. Tracers seeded in the upstream alluvial channel moved more slowly than elsewhere until the frontrunners reached bare rock and sped up. Tracers seeded on bare rock moved rapidly off it and accumulated just upstream from, and later in, a partial-cover zone with many boulders. The backwater effect of the boulder-rich zone is significant in reducing tracer mobility. Tracer movement over full or partial sediment cover was size selective but dispersion over bare rock was not. Along-channel changes in tracer mobility are interpreted in terms of measured differences in shear stress and estimated differences in threshold stress.

A study on the use of the BioBall® as a biofilm carrier in a sequencing batch reactor.

PubMed

Masłoń, Adam; Tomaszek, Janusz A

2015-11-01

Described in this study are experiments conducted to evaluate the removal of organics and nutrients from synthetic wastewater by a moving bed sequencing batch biofilm reactor using BioBall® carriers as biofilm media. The work involving a 15L-laboratory scale MBSBBR (moving bed sequencing batch biofilm reactor) model showed that the wastewater treatment system was based on biochemical processes taking place with activated sludge and biofilm microorganisms developing on the surface of the BioBall® carriers. Classical nitrification and denitrification and the typical enhanced biological phosphorus removal process were achieved in the reactor analyzed, which operated with a volumetric organic loading of 0.84-0.978gCODL(-1)d(-1). The average removal efficiencies for COD, total nitrogen and total phosphorus were found to be 97.7±0.5%, 87.8±2.6% and 94.3±1.3%, respectively. Nitrification efficiency reached levels in the range 96.5-99.7%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Optimization of the moving-bed biofilm sequencing batch reactor (MBSBR) to control aeration time by kinetic computational modeling: Simulated sugar-industry wastewater treatment.

PubMed

Faridnasr, Maryam; Ghanbari, Bastam; Sassani, Ardavan

2016-05-01

A novel approach was applied for optimization of a moving-bed biofilm sequencing batch reactor (MBSBR) to treat sugar-industry wastewater (BOD5=500-2500 and COD=750-3750 mg/L) at 2-4 h of cycle time (CT). Although the experimental data showed that MBSBR reached high BOD5 and COD removal performances, it failed to achieve the standard limits at the mentioned CTs. Thus, optimization of the reactor was rendered by kinetic computational modeling and using statistical error indicator normalized root mean square error (NRMSE). The results of NRMSE revealed that Stover-Kincannon (error=6.40%) and Grau (error=6.15%) models provide better fits to the experimental data and may be used for CT optimization in the reactor. The models predicted required CTs of 4.5, 6.5, 7 and 7.5 h for effluent standardization of 500, 1000, 1500 and 2500 mg/L influent BOD5 concentrations, respectively. Similar pattern of the experimental data also confirmed these findings. Copyright © 2016 Elsevier Ltd. All rights reserved.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biodegradation of atrazine from wastewater using moving bed biofilm reactor under nitrate-reducing conditions: A kinetic study.

PubMed

Derakhshan, Zahra; Ehrampoush, Mohammad Hassan; Mahvi, Amir Hossein; Ghaneian, Mohammad Taghi; Mazloomi, Seyed Mohammad; Faramarzian, Mohammad; Dehghani, Mansooreh; Fallahzadeh, Hossein; Yousefinejad, Saeed; Berizi, Enayat; Bahrami, Shima

2018-04-15

In this study employed an anoxic moving bed biofilm reactor (AnMBBR) to evaluate the effects of hydraulic and toxic shocks on performance reactor. The results indicated a relatively good resistance of system against exercised shocks and its ability to return to steady-state conditions. In optimal conditions when there was the maximum rate of atrazine and soluble chemical oxygen demand (COD) removal were 74.82% and 99.29% respectively. Also, atrazine biodegradation rapidly declines in AnMBBR from 74% ± 0.05 in the presence of nitrate to 9.12% only 3 days after the nitrate was eliding from the influent. Coefficients kinetics was studied and the maximum atrazine removal rate was determined by modified Stover & Kincannon model (U max  = 9.87 g ATZ /m 3 d). Results showed that AnMBBR is feasible, easy, affordable, so suitable process for efficiently biodegrading toxic chlorinated organic compounds such as atrazine. Also, its removal mechanism in this system is co-metabolism. Copyright © 2018 Elsevier Ltd. All rights reserved.

Model-based design of an intermittent simulated moving bed process for recovering lactic acid from ternary mixture.

PubMed

Song, Mingkai; Cui, Linlin; Kuang, Han; Zhou, Jingwei; Yang, Pengpeng; Zhuang, Wei; Chen, Yong; Liu, Dong; Zhu, Chenjie; Chen, Xiaochun; Ying, Hanjie; Wu, Jinglan

2018-08-10

An intermittent simulated moving bed (3F-ISMB) operation scheme, the extension of the 3W-ISMB to the non-linear adsorption region, has been introduced for separation of glucose, lactic acid and acetic acid ternary-mixture. This work focuses on exploring the feasibility of the proposed process theoretically and experimentally. Firstly, the real 3F-ISMB model coupled with the transport dispersive model (TDM) and the Modified-Langmuir isotherm was established to build up the separation parameter plane. Subsequently, three operating conditions were selected from the plane to run the 3F-ISMB unit. The experimental results were used to verify the model. Afterwards, the influences of the various flow rates on the separation performances were investigated systematically by means of the validated 3F-ISMB model. The intermittent-retained component lactic acid was finally obtained with the purity of 98.5%, recovery of 95.5% and the average concentration of 38 g/L. The proposed 3F-ISMB process can efficiently separate the mixture with low selectivity into three fractions. Copyright © 2018 Elsevier B.V. All rights reserved.

Experimental evaluation of the effect of a modified port-location mode on the performance of a three-zone simulated moving-bed process for the separation of valine and isoleucine.

PubMed

Park, Chanhun; Nam, Hee-Geun; Kim, Pung-Ho; Mun, Sungyong

2014-06-01

The removal of isoleucine from valine has been a key issue in the stage of valine crystallization, which is the final step in the valine production process in industry. To address this issue, a three-zone simulated moving-bed (SMB) process for the separation of valine and isoleucine has been developed previously. However, the previous process, which was based on a classical port-location mode, had some limitations in throughput and valine product concentration. In this study, a three-zone SMB process based on a modified port-location mode was applied to the separation of valine and isoleucine for the purpose of making a marked improvement in throughput and valine product concentration. Computer simulations and a lab-scale process experiment showed that the modified three-zone SMB for valine separation led to >65% higher throughput and >160% higher valine concentration compared to the previous three-zone SMB for the same separation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Standing wave design and experimental validation of a tandem simulated moving bed process for insulin purification.

PubMed

Xie, Yi; Mun, Sungyong; Kim, Jinhyun; Wang, Nien-Hwa Linda

2002-01-01

A tandem simulated moving bed (SMB) process for insulin purification has been proposed and validated experimentally. The mixture to be separated consists of insulin, high molecular weight proteins, and zinc chloride. A systematic approach based on the standing wave design, rate model simulations, and experiments was used to develop this multicomponent separation process. The standing wave design was applied to specify the SMB operating conditions of a lab-scale unit with 10 columns. The design was validated with rate model simulations prior to experiments. The experimental results show 99.9% purity and 99% yield, which closely agree with the model predictions and the standing wave design targets. The agreement proves that the standing wave design can ensure high purity and high yield for the tandem SMB process. Compared to a conventional batch SEC process, the tandem SMB has 10% higher yield, 400% higher throughput, and 72% lower eluant consumption. In contrast, a design that ignores the effects of mass transfer and nonideal flow cannot meet the purity requirement and gives less than 96% yield.

Microalgal growth in municipal wastewater treated in an anaerobic moving bed biofilm reactor.

PubMed

Hultberg, Malin; Olsson, Lars-Erik; Birgersson, Göran; Gustafsson, Susanne; Sievertsson, Bertil

2016-05-01

Nutrient removal from the effluent of an anaerobic moving bed biofilm reactor (AnMBBR) treated with microalgae was evaluated. Algal treatment was highly efficient in removal of nutrients and discharge limits were met after 3days. Extending the cultivation time from 3 to 5days resulted in a large increase in biomass, from 233.3±49.3 to 530.0±72.1mgL(-1), despite nutrients in the water being exhausted after 3days (ammonium 0.04mgL(-1), orthophosphate <0.05mgL(-1)). Biomass productivity, lipid content and quality did not differ in microalgal biomass produced in wastewater sampled before the AnMBBR. The longer cultivation time resulted in a slight increase in total lipid concentration and a significant decrease in linolenic acid concentration in all treatments. Differences were observed in chemical oxygen demand, which decreased after algal treatment in wastewater sampled before the AnMBBR whereas it increased after algal treatment in the effluent from the AnMBBR. Copyright © 2016 Elsevier Ltd. All rights reserved.

Peering inside the granular bed: illuminating feedbacks between bed-load transport and bed-structure evolution

NASA Astrophysics Data System (ADS)

Houssais, M.; Jerolmack, D. J.; Martin, R. L.

2013-12-01

The threshold of motion is perhaps the most important quantity to determine for understanding rates of bed load transport, however it is a moving target. Decades of research show that it changes in space and in time within a river, and is highly variable among different systems; however, these differences are not mechanistically understood. Recent researchers have proposed that the critical Shields stress is strongly dependent on the local configuration of the sediment bed [Frey and Church, 2011]. Critical Shields stress has been observed to change following sediment-transporting flood events in natural rivers [e.g., Turowski et al., 2011], while small-scale laboratory experiments have produced declining bed load transport rates associated with slow bed compaction [Charru et al., 2004]. However, no direct measurements have been made of the evolving bed structure under bed load transport, so the connection between granular controls and the threshold of motion remains uncertain. A perspective we adopt is that granular effects determine the critical Shields stress, while the fluid supplies a distribution of driving stresses. In order to isolate the granular effect, we undertake laminar bed load transport experiments using plastic beads sheared by a viscous oil in a small, annular flume. The fluid and beads are refractive index matched, and the fluid impregnated with a fluorescing powder. When illuminated with a planar laser sheet, we are able to image slices of the granular bed while also tracking the overlying sediment transport. We present the first results showing how bed load transport influences granular packing, and how changes in packing influence the threshold of motion to feed back on bed load transport rates. This effect may account for much of the variability observed in the threshold of motion in natural streams, and by extension offers a plausible explanation for hysteresis in bed load transport rates observed during floods. Charru, F., H. Mouilleron, and O. Eiff, Erosion and deposition of particles on a bed sheared by a viscous flow, Journal of Fluid Mech., 519, 55-80, 2004 Frey, P. and Church, M. (2011), Bedload: a granular phenomenon. Earth Surf. Process. Landforms, 36: 58-69. doi: 10.1002/esp.2103 Turowski, J. M., A. Badoux, and D. Rickenmann (2011), Start and end of bedload transport in gravel-bed streams, Geophys. Res. Lett., 38, L04401, doi:10.1029/2010GL046558.

Countercurrent Chromatographic Separation of Proteins Using an Eccentric Coiled Column with Synchronous and Nonsynchronous Type-J Planetary Motions

PubMed Central

SHINOMIYA, Kazufusa; YOSHIDA, Kazunori; TOKURA, Koji; TSUKIDATE, Etsuhiro; YANAGIDAIRA, Kazuhiro; ITO, Yoichiro

2015-01-01

Protein separation was performed using the high-speed counter-current chromatograph (HSCCC) at both synchronous and nonsynchronous type-J planetary motions. The partition efficiency was evaluated with two different column configurations, eccentric coil and toroidal coil, on the separation of a set of stable protein samples including cytochrome C, myoglobin and lysozyme with a polymer phase system composed of 12.5% (w/w) polyethylene glycol 1000 and 12.5% (w/w) dibasic potassium phosphate. Better peak resolution was obtained by the eccentric coil than by the toroidal coil using either lower or upper phase as the mobile phase. The peak resolution was further improved using the eccentric coil by the nonsynchronous type-J planetary motion with the combination of 1066 rpm of column rotation and 1000 rpm of revolution. PMID:25765276

Countercurrent chromatographic separation of proteins using an eccentric coiled column with synchronous and nonsynchronous type-J planetary motions.

PubMed

Shinomiya, Kazufusa; Yoshida, Kazunori; Tokura, Koji; Tsukidate, Etsuhiro; Yanagidaira, Kazuhiro; Ito, Yoichiro

2015-01-01

Protein separation was performed using the high-speed countercurrent chromatograph (HSCCC) at both synchronous and nonsynchronous type-J planetary motions. The partition efficiency was evaluated with two different column configurations, eccentric coil and toroidal coil, on the separation of a set of stable protein samples including cytochrome C, myoglobin and lysozyme with a polymer phase system composed of 12.5% (w/w) polyethylene glycol 1000 and 12.5% (w/w) dibasic potassium phosphate. Better peak resolution was obtained by the eccentric coil than by the toroidal coil using either lower or upper phase as the mobile phase. The peak resolution was further improved using the eccentric coil by the nonsynchronous type-J planetary motion with the combination of 1066 rpm of column rotation and 1000 rpm of revolution.

Isolation of cyanidin 3-glucoside from blue honeysuckle fruits by high-speed counter-current chromatography.

PubMed

Chen, Liang; Xin, Xiulan; Lan, Rong; Yuan, Qipeng; Wang, Xiaojie; Li, Ye

2014-01-01

Blue honeysuckle fruits are rich in anthocyanins with many beneficial effects such as reduction of the risk of cardiovascular diseases, diabetes and cancers. High-speed counter-current chromatography (HSCCC) was used for the separation of anthocyanin on a preparative scale from blue honeysuckle fruit crude extract with a biphasic solvent system composed of tert-butyl methyl ether/n-butanol/acetonitrile/water/trifluoroacetic acid (2:2:1:5:0.01, v/v) for the first time in this paper. Each injection of 100 mg crude extract yielded 22.8 mg of cyanidin 3-glucoside (C3G) at 98.1% purity. The compound was identified by means of electro-spray ionisation mass (ESI/MS) and (1)H and (13)C nuclear magnetic resonance (NMR) spectra. Copyright © 2013 Elsevier Ltd. All rights reserved.

Countercurrent flow of supercritical anti-solvent in the production of pure xanthophylls from Nannochloropsis oculata.

PubMed

Cho, Yueh-Cheng; Wang, Yuan-Chuen; Shieh, Chwen-Jen; Lin, Justin Chun-Te; Chang, Chieh-Ming J; Han, Esther

2012-08-10

This study examined pilot scaled elution chromatography coupled with supercritical anti-solvent precipitation (using countercurrent flow) in generating zeaxanthin-rich particulates from a micro-algal species. Ultrasonic agitated acetone extract subjected to column fractionation successfully yielded a fraction containing 349.4 mg/g of zeaxanthin with a recovery of 85%. Subsequently, supercritical anti-solvent (SAS) precipitation of the column fraction at 150 bar and 343 K produced submicron-sized particulates with a concentration of 845.5mg/g of zeaxanthin with a recovery of 90%. Experimental results from a two-factor response surface method SAS precipitation indicated that purity, mean size and morphology of the precipitates were significantly affected by the flow type configuration, feed flow rate and injection time. Copyright © 2012 Elsevier B.V. All rights reserved.

Isolation of sutherlandins A, B, C and D from Sutherlandia frutescens (L.) R. Br. by counter-current chromatography using spiral tubing support rotors.

PubMed

Chen, Cuiping; Folk, William R; Lazo-Portugal, Rodrigo; Finn, Thomas M; Knight, Martha

2017-07-28

Spiral countercurrent-chromatography has great potential for improving the capacity and efficiency of purification of secondary metabolites, and here we describe applications useful for the isolation of flavonoids from the widely used South African medicinal plant, Sutherlandia frutescens (L.) R. Br. In the spiral tubing support rotor, STS-4 for high-speed counter-current chromatography, several polar butanol aqueous solvent systems were selected using a logK plot, and the novel flavonol glycosides (sutherlandins A-D) were well separated by the optimized solvent system (ethyl acetate:n-butanol:acetic acid:water; 5:1:0.3:6 by vol.). The yield of purified flavonoids from 0.9g extract varied from 8.6mg to 54mg of the sutherlandins for a total of 85.3mg. The same extract was fractionated in the new STS-12 rotor of the same outside dimensions but with more radial channels forming 12 loops of the tubing instead of 4. The rotor holds more layers and increased length of tubing. From 0.9g extract the STS-12 rotor yielded more recovery of 110.4mg total with amounts varying from 11.2mg to 64mg of the sutherlandins and apparent increased separation efficiency as noted by less volume of each fraction peak. Thus from 1-g amounts of extract, good recovery of the flavonoids was achieved in the butanol aqueous solvent system. Copyright © 2017 Elsevier B.V. All rights reserved.

Isolation and purification of two antioxidant isomers of resveratrol dimer from the wine grape by counter-current chromatography.

PubMed

Kong, Qingjun; Ren, Xueyan; Hu, Ruilin; Yin, Xuefeng; Jiang, Guoshan; Pan, Yuanjiang

2016-06-01

Resveratrol dimers belong to a group of compounds called stilbenes, which along with proanthocyanidins, anthocyanins, catechins, and flavonols are natural phenolic compounds found in grapes and red wine. Stilbenes have a variety of structural isomers, all of which exhibit various biological properties. Counter-current chromatography with a two-phase solvent system composed of n-hexane/ethyl acetate/methanol/water (2:5:4:5, v/v/v/v) was applied to isolate and purify stilbene from the stems of wine grape. Two isomers of resveratrol dimers trans-ε-viniferin and trans-δ-viniferin were obtained from the crude sample in a one-step separation, with purities of 93.2 and 97.5%, respectively, as determined by high-performance liquid chromatography. The structures of these two compounds were identified by (1) H and (13) C NMR spectroscopy. In addition, their antioxidant activities were assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The antioxidant activities of trans-δ-viniferin were higher than that of trans-ε-viniferin in this model. This work demonstrated that counter-current chromatography is a powerful and effective method for the isolation and purification of polyphenols from wine grape. Additionally, the DPPH radical assay showed that the isolated component trans-δ-viniferin exhibited stronger antioxidant activities than trans-ε-viniferin and a little bit weaker than vitamin E at the same concentration. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Improvement of the performances of a tandem simulated moving bed chromatography by controlling the yield level of a key product of the first simulated moving bed unit.

PubMed

Mun, Sungyong; Wang, Nien-Hwa Linda

2017-03-10

One of the trustworthy processes for ternary separation is a tandem simulated moving bed (SMB) process, which consists of two subordinate four-zone SMB units (Ring I and Ring II). To take full advantage of a tandem SMB as a means of recovering all three products with high purities and high economical efficiency, it is important to understand how the separation condition in Ring II is affected by that in Ring I, and further to reflect such point in the stage of designing a tandem SMB. In regard to such issue, it was clarified in this study that the Ring I factors affecting the Ring II condition could be represented by the yield level of a key product of Ring I (Y key RingI ). As the Y key RingI level became higher, the amount of the Ring I key-product that was reloaded into Ring II was reduced, which affected favorably the Ring II separation condition. On the other hand, the higher Y key RingI level caused a larger dilution for the stream from Ring I to Ring II, which affected adversely the Ring II separation condition. As a result, a minimum in the desorbent usage of a tandem SMB occurred at the Y key RingI level where the two aforementioned factors could be balanced with each other. If such an optimal Y key RingI level was adopted, the desorbent usage could be reduced by up to 25%. It was also found that as the throughput of a tandem SMB became higher, the factor related to the migration of the Ring I key-product into Ring II was more influential in the performances of a tandem SMB than the factor related to the dilution of the stream from Ring I to Ring II. Copyright © 2016 Elsevier B.V. All rights reserved.

Model-based design of a pilot-scale simulated moving bed for purification of citric acid from fermentation broth.

PubMed

Wu, Jinglan; Peng, Qijun; Arlt, Wolfgang; Minceva, Mirjana

2009-12-11

One of the conventional processes used for the recovery of citric acid from its fermentation broth is environmentally harmful and cost intensive. In this work an innovative benign process, which comprises simulated moving bed (SMB) technology and use of a tailor-made tertiary poly(4-vinylpyridine) (PVP) resin as a stationary phase is proposed. This paper focuses on a model-based design of the operation conditions for an existing pilot-scale SMB plant. The SMB unit is modeled on the basis of experimentally determined hydrodynamics, thermodynamics and mass transfer characteristics in a single chromatographic column. Three mathematical models are applied and validated for the prediction of the experimentally attained breakthrough and elution profiles of citric acid and the main impurity component (glucose). The transport dispersive model was selected for the SMB simulation and design studies, since it gives a satisfactory prediction of the elution profiles within acceptable computational time. The equivalent true moving bed (TMB) and SMB models give a good prediction of the experimentally attained SMB separation performances, obtained with a real clarified and concentrated fermentation broth as a feed mixture. The SMB separation requirements are set to at least 99.8% citric acid purity and 90% citric acid recovery in the extract stream. The complete regeneration in sections 1 and 4 is unnecessary. Therefore the net flow rates in all four SMB sections have been considered in the unit design. The influences of the operating conditions (the flow rate in each section, switching time and unit configuration) on the SMB performances were investigated systematically. The resulting SMB design provides 99.8% citric acid purity and 97.2% citric acid recovery in the extract. In addition the citric acid concentration in the extract is a half of its concentration in the pretreated fermentation broth (feed).

Seismogenic rotational slumps and translational glides in pelagic deep-water carbonates. Upper Tithonian-Berriasian of Southern Tethyan margin (W Sicily, Italy)

NASA Astrophysics Data System (ADS)

Basilone, Luca

2017-07-01

Soft-sediment deformation structures (SSDSs), which reflect sediment mobilization processes, are helpful to identify punctual events of paleoenvironmental stresses. In the upper Tithonian-Berriasian calpionellid pelagic limestone of the Lattimusa Fm. outcropping in the Barracù section (W Sicily), paleoenvironmental restoration reveals the occurrence of a deep-water flat basin, characterised by undeformed planar bedding, laterally passing to a gentle slope where the deformed horizons alternate with undeformed beds. Here, two types of gravity slides have been differentiated on the basis of different kinds of SSDSs, brittle deformation, involved lithofacies, geometry and morphology. Type 1 slump sheets, involving marl-limestone couplets, are characterised by chaotic stratification, truncated beds, recumbent folds, tension gashes, clastic dikes and small-scale listric normal faults and thrusts. They moved downslope as a rotational slump, displaying the typical wedge-shaped morphology, becoming thicker toe-wards. Type 2 slump sheets, involving bed packages of lime mudstone, are characterised by arcuate slump scars developing downwards as listric normal faults, associated with rotational beds and bulging. Displaying tabular geometries, they moved coherently along an overall bedding parallel detachment surface as a translational glide characterised by sediment creep. Regional geology indicates that the basin (Sicanian), bordered by a stepped carbonate platform, was affected by synsedimentary tectonics throughout the Mesozoic. The synsedimentary extensional tectonics that affect the Upper Triassic-Jurassic deposits with steeped normal faults, causing tilt-block and instability of the seafloor through fluidization processes, triggered the rotational slumps of the lower portion of the section. Seismic shocks, induced by outside sector tectonics, like those recorded in the adjacent Busambra stepped carbonate platform margin, triggered the rotational slumps that are not related to local-scale faults. To explain the translational glides of the upper portion of the section, the aforementioned outside sector earthquakes produced instability of the sea-floor through thixotropy of marls. In this case, the driving forces (i.e., gravitational) were favoured by the uplifting trend that is well recorded in the Southern Tethyan continental margin. We suggest that the various early deformations represent rotational slump and sediment creep that may be characteristic for slump structures in pelagic carbonates, depending on the involved lithologies (i.e., paleoenvironmental setting) and the intensity/distance of the trigger mechanism (i.e., earthquake epicentre).

Hydrologic environment of the Silurian salt deposits in parts of Michigan, Ohio, and New York

USGS Publications Warehouse

Norris, Stanley E.

1978-01-01

The aggregate thickness of evaporites (salt, gypsum, and anhydrite) in the Silurian Salina sequence in Michigan exceeds 1200 feet in areas near the periphery of the Michigan basin, where the salt beds are less than 3000 feet below land surface. In northeast Ohio the aggregate thickness of salt beds is as much as 200 feet in places, and in western New York it is more than 500 feet, where th beds are less than 3000 feet deep. The salt-bearing rocks dip regionally on the order of 50 feet per mile; those in Michigan dip toward the center of the Michigan basin, and those in Ohio and New York, in the Appalachian basin, dip generally southward. The rocks in both basins thicken downdip. Minor folds and faults occur in the salt-bearing rocks in all three states. Some of this defrmation has been attenuated or absorbed bo the salt beds. Occuring near the middle of thick sedimentary sequences, the salt beds are bounded aboe and below by beds containing water having dissolved-solids concentrations several times that seawter. The brines occur commonly in discrete zones of high permeability at specific places in the stratigraphic sequence. In northeast Ohio two prominent brine zones are recognized by the driller, the Devonian Oriskany Sandstone, or 'first water' zone, above the Salina Formation, and the Newburg or 'second water' zone below the Salina. In each aquifer there is a vertical component of hydraulic head, but little brine probably moves through the salt beds because their permeability is extremely low. Also, ther is little evidence of dissolution of the salt in areas distant from the outcrop, suggesting that if brine does move through the salt, movement is at a slow enough rate so that, in combination with the saturated or near-saturated condition of the water, it precludes significant dissolution. Principal brine movement is probably in the permeable zones in the direction of the hydraulic gradient. Two areas in Michigan and one area each in Ohio and New York appear suitable for additional investigation of salt beds for purposes radioactive waste disposal. One of the Michigan areas is in the northern part of the southern peninsula, in Presque Isle and Alpena Counties; the other is in the southern part of the southern peninsula, in Oakland, Macomb, and St. Clair Counties (fig. 3). In northeast Ohio the area that appears to be suitable for investigation includes most of the eastern half of Lake County and extends eastward into Ashtabula County and southward into Geauga County. In western New York conditions may warrant additional investigation in Schuyler, Tompkins, and western Cortland Counties.

Beyond the threshold for motion: river channel geometry and grain size reflect sediment supply

NASA Astrophysics Data System (ADS)

Pfeiffer, A.; Finnegan, N. J.; Willenbring, J. K.

2016-12-01

In many gravel-bedded rivers, floods that fill the ch­­annel banks create just enough shear stress to move the median-sized gravel particles on the bed surface (D50). Because this observation is common and is supported by theory, the coincidence of bankfull flow and the incipient motion of D50 has become a­­ commonly employed assumption. However, not all natural gravel channels actually conform to this simple relationship; some channels maintain bankfull stresses far in excess of the critical stress required to initiate sediment transport. We use a database of >300 gravel-bedded rivers and >600 10Be-derived erosion rates from across North America to explore the hypothesis that sediment supply drives the magnitude of bankfull shear stress relative to the critical stress required to mobilize the median bed surface grain size. We find that the ratio of bankfull to critical stress is significantly higher in West Coast river reaches (2.47, n= 84) than in river reaches in the rest of the continent (1.03, n = 245). This pattern parallels trends in erosion rates (and hence sediment supplies). Supporting our hypothesis, we find a significant correlation between upstream erosion rate and local τ*bf/τ*c at sites where this comparison is possible. Our analysis reveals a decrease in bed surface armoring with increasing τ*bf/τ*c, suggesting that channels accommodate changes in sediment supply through adjustments in bed surface grain size, as predicted through numerical modeling. Our findings demonstrate that sediment supply is encoded in the bankfull hydraulic geometry of gravel-bedded channels through its control on bed surface grain size.

Identification of discontinuous sand pulses on the bed of the Colorado River in Grand Canyon

NASA Astrophysics Data System (ADS)

Mueller, E. R.; Grams, P. E.; Buscombe, D.; Topping, D. J.

2017-12-01

Decades of research on alluvial sandbars and sand transport on the Colorado River in Grand Canyon has contributed to in-depth understanding of the sand budget and lead to management actions designed to rebuild eroded sandbars. However, some basic, but difficult to address, questions about the processes and rates of sand movement through the system still limit our ability to predict geomorphic responses. The coarse fraction of the bed is heterogeneous and varies among boulders, cobble, gravel, and bedrock. Sand covers these substrates in patches of variable size and thickness, fills interstices to varying degrees, and forms mixed sand/coarse bed configurations such as linear stripes. Understanding the locations of sand accumulation, the quantities of sand contained in those locations, and the processes by which sand is exchanged among depositional locations is needed to predict the morphological response of sandbars to management actions, such as the controlled flood releases, and to predict whether sandbars are likely to increase or decrease in size over long (i.e. decadal) time periods. Here, we present evidence for the downstream translation of the sand component of tributary sediment inputs as discontinuous sand pulses. The silt and clay (mud) fraction of sediment introduced episodically by seasonal floods from tributary streams is transported entirely in suspension and moves through the 400 km series of canyons in a few days. The sand fraction of this sediment, which is transported on the bed and in suspension, moves downstream in sand pulses that we estimate range in length from a few km to tens of km. Owing to the complex geomorphic organization, the sand pulses are not detectable as coherent bed features; each individual sand pulse is comprised of many isolated storage locations, separated by rapids and riffles where sand cover is sparse. The presence of the sand pulses is inferred by the existence of alternating segments of sand accumulation and depletion computed from repeat maps of the channel. Improved understanding of the behavior of these sand pulses may be used to adjust the timing, magnitude, and duration of controlled floods to maximize potential for deposition on sandbars in different segments of the 450 km-long Grand Canyon.

Response of bed surface patchiness to reductions in sediment supply

NASA Astrophysics Data System (ADS)

Nelson, Peter A.; Venditti, Jeremy G.; Dietrich, William E.; Kirchner, James W.; Ikeda, Hiroshi; Iseya, Fujiko; Sklar, Leonard S.

2009-06-01

River beds are often arranged into patches of similar grain size and sorting. Patches can be distinguished into "free patches," which are zones of sorted material that move freely, such as bed load sheets; "forced patches," which are areas of sorting forced by topographic controls; and "fixed patches" of bed material rendered immobile through localized coarsening that remain fairly persistent through time. Two sets of flume experiments (one using bimodal, sand-rich sediment and the other using unimodal, sand-free sediment) are used to explore how fixed and free patches respond to stepwise reductions in sediment supply. At high sediment supply, migrating bed load sheets formed even in unimodal, sand-free sediment, yet grain interactions visibly played a central role in their formation. In both sets of experiments, reductions in supply led to the development of fixed coarse patches, which expanded at the expense of finer, more mobile patches, narrowing the zone of active bed load transport and leading to the eventual disappearance of migrating bed load sheets. Reductions in sediment supply decreased the migration rate of bed load sheets and increased the spacing between successive sheets. One-dimensional morphodynamic models of river channel beds generally are not designed to capture the observed variability, but should be capable of capturing the time-averaged character of the channel. When applied to our experiments, a 1-D morphodynamic model (RTe-bookAgDegNormGravMixPW.xls) predicted the bed load flux well, but overpredicted slope changes and was unable to predict the substantial variability in bed load flux (and load grain size) because of the migration of mobile patches. Our results suggest that (1) the distribution of free and fixed patches is primarily a function of sediment supply, (2) the dynamics of bed load sheets are primarily scaled by sediment supply, (3) channels with reduced sediment supply may inherently be unable to transport sediment uniformly across their width, and (4) cross-stream variability in shear stress and grain size can produce potentially large errors in width-averaged sediment flux calculations.

Forces on stationary particles in near-bed turbulent flows

NASA Astrophysics Data System (ADS)

Schmeeckle, Mark W.; Nelson, Jonathan M.; Shreve, Ronald L.

2007-06-01

In natural flows, bed sediment particles are entrained and moved by the fluctuating forces, such as lift and drag, exerted by the overlying flow on the particles. To develop a better understanding of these forces and the relation of the forces to the local flow, the downstream and vertical components of force on near-bed fixed particles and of fluid velocity above or in front of them were measured synchronously at turbulence-resolving frequencies (200 or 500 Hz) in a laboratory flume. Measurements were made for a spherical test particle fixed at various heights above a smooth bed, above a smooth bed downstream of a downstream-facing step, and in a gravel bed of similarly sized particles as well as for a cubical test particle and 7 natural particles above a smooth bed. Horizontal force was well correlated with downstream velocity and not correlated with vertical velocity or vertical momentum flux. The standard drag formula worked well to predict the horizontal force, but the required value of the drag coefficient was significantly higher than generally used to model bed load motion. For the spheres, cubes, and natural particles, average drag coefficients were found to be 0.76, 1.36, and 0.91, respectively. For comparison, the drag coefficient for a sphere settling in still water at similar particle Reynolds numbers is only about 0.4. The variability of the horizontal force relative to its mean was strongly increased by the presence of the step and the gravel bed. Peak deviations were about 30% of the mean force for the sphere over the smooth bed, about twice the mean with the step, and 4 times it for the sphere protruding roughly half its diameter above the gravel bed. Vertical force correlated poorly with downstream velocity, vertical velocity, and vertical momentum flux whether measured over or ahead of the test particle. Typical formulas for shear-induced lift based on Bernoulli's principle poorly predict the vertical forces on near-bed particles. The measurements suggest that particle-scale pressure variations associated with turbulence are significant in the particle momentum balance.

Forces on stationary particles in near-bed turbulent flows

USGS Publications Warehouse

Schmeeckle, M.W.; Nelson, J.M.; Shreve, R.L.

2007-01-01

In natural flows, bed sediment particles are entrained and moved by the fluctuating forces, such as lift and drag, exerted by the overlying flow on the particles. To develop a better understanding of these forces and the relation of the forces to the local flow, the downstream and vertical components of force on near-bed fixed particles and of fluid velocity above or in front of them were measured synchronously at turbulence-resolving frequencies (200 or 500 Hz) in a laboratory flume. Measurements were made for a spherical test particle fixed at various heights above a smooth bed, above a smooth bed downstream of a downstream-facing step, and in a gravel bed of similarly sized particles as well as for a cubical test particle and 7 natural particles above a smooth bed. Horizontal force was well correlated with downstream velocity and not correlated with vertical velocity or vertical momentum flux. The standard drag formula worked well to predict the horizontal force, but the required value of the drag coefficient was significantly higher than generally used to model bed load motion. For the spheres, cubes, and natural particles, average drag coefficients were found to be 0.76, 1.36, and 0.91, respectively. For comparison, the drag coefficient for a sphere settling in still water at similar particle Reynolds numbers is only about 0.4. The variability of the horizontal force relative to its mean was strongly increased by the presence of the step and the gravel bed. Peak deviations were about 30% of the mean force for the sphere over the smooth bed, about twice the mean with the step, and 4 times it for the sphere protruding roughly half its diameter above the gravel bed. Vertical force correlated poorly with downstream velocity, vertical velocity, and vertical momentum flux whether measured over or ahead of the test particle. Typical formulas for shear-induced lift based on Bernoulli's principle poorly predict the vertical forces on near-bed particles. The measurements suggest that particle-scale pressure variations associated with turbulence are significant in the particle momentum balance. Copyright 2007 by the American Geophysical Union.

Atmospheric volatilization and distribution of (Z)- and (E)-1,3-dichloropropene in field beds with and without plastic covers.

PubMed

Thomas, John E; Allen, L Hartwell; McCormack, Leslie A; Vu, Joseph C; Dickson, Donald W; Ou, Li-Tse

2004-01-01

The fumigant 1,3-dichloropropene (1,3-D) is considered to be a potential replacement for methyl bromide when methyl bromide is phased out in 2005. This study on surface emissions and subsurface diffusion of 1,3-D in a Florida sandy soil was conducted in field beds with or without plastic covers. After injection of the commercial fumigant Telone II by conventional chisels to field beds at 30cm depth which were covered with polyethylene film (PE), virtually impermeable film, or no cover (bare), (Z)- and (E)-1,3-D rapidly diffused upward. Twenty hours after injection, majority of (Z)- and (E)-1,3-D had moved upward from 30 cm depth to the layer of 5-20 cm depth. Downward movement of the two isomers in the beds with or without a plastic cover was not significant. (Z)-1,3-D diffused more rapidly than (E)-1,3-D. Virtually impermeable films (VIF) had a good capacity to retain (Z)- and (E)-1,3-D in soil pore air space. Vapor concentrations of the two isomers in the shallow subsurface of the field bed covered with VIF were greater than that in the two beds covered with polyethylene film (PE) or no cover (bare). In addition, VIF cover provided more uniform distribution of (Z)- and (E)-1,3-D in shallow subsurface than PE cover or no cover. Virtually impermeable film also had a better capability to retard surface emissions of the two isomers from soil in field beds than PE cover or no cover.

Interplay between spatially explicit sediment sourcing, hierarchical river-network structure, and in-channel bed material sediment transport and storage dynamics

NASA Astrophysics Data System (ADS)

Czuba, Jonathan A.; Foufoula-Georgiou, Efi; Gran, Karen B.; Belmont, Patrick; Wilcock, Peter R.

2017-05-01

Understanding how sediment moves along source to sink pathways through watersheds—from hillslopes to channels and in and out of floodplains—is a fundamental problem in geomorphology. We contribute to advancing this understanding by modeling the transport and in-channel storage dynamics of bed material sediment on a river network over a 600 year time period. Specifically, we present spatiotemporal changes in bed sediment thickness along an entire river network to elucidate how river networks organize and process sediment supply. We apply our model to sand transport in the agricultural Greater Blue Earth River Basin in Minnesota. By casting the arrival of sediment to links of the network as a Poisson process, we derive analytically (under supply-limited conditions) the time-averaged probability distribution function of bed sediment thickness for each link of the river network for any spatial distribution of inputs. Under transport-limited conditions, the analytical assumptions of the Poisson arrival process are violated (due to in-channel storage dynamics) where we find large fluctuations and periodicity in the time series of bed sediment thickness. The time series of bed sediment thickness is the result of dynamics on a network in propagating, altering, and amalgamating sediment inputs in sometimes unexpected ways. One key insight gleaned from the model is that there can be a small fraction of reaches with relatively low-transport capacity within a nonequilibrium river network acting as "bottlenecks" that control sediment to downstream reaches, whereby fluctuations in bed elevation can dissociate from signals in sediment supply.

Health Occupations Curriculum. Skills for Nursing Assistant. Volume 3, Unit 8.

ERIC Educational Resources Information Center

Arizona State Dept. of Education, Phoenix.

Part of a health occupations program, this instructional unit contains 13 learning modules for use in training nursing assistants. Covered in the modules are (1) making beds, bathing patients, and measuring intake and output; (2) body mechanics, moving and lifting patients, range of motion exercises, and caring for patients in casts or traction;…

Get Kids Moving: Simple Activities To Build Gross-Motor Skills.

ERIC Educational Resources Information Center

Texas Child Care, 2003

2003-01-01

Highlights the importance of activities to build gross motor skills and provides hints for encouraging such activities. Specific areas of activities presented are: (1) running and jumping; (2) music games; (3) action games; (4) races; (5) bed sheets or parachutes; (6) hula hoops; (7) balls; (8) batting; (9) balance; and (10) creative movement. (SD)

Patient's breath controls comfort devices

NASA Technical Reports Server (NTRS)

Schrader, M.; Carpenter, B.; Nichols, C. D.

1972-01-01

Patient assist system for totally disabled persons was developed which permits a person, so paralyzed as to be unable to move, to activate by breathing, a call system to summon assistance, turn the page of a book, ajust his bed, or do any one of a number of other things. System consists of patient assist control and breath actuated switch.

Defining phases of bedload transport using piecewise regression

Treesearch

Sandra E. Ryan; Laurie S. Porth; C. A. Troendle

2002-01-01

Differences in the transport rate and size of bedload exist for varying levels of flow in coarse-grained channels. For gravel-bed rivers, at least two phases of bedload transport, with notably differing qualities, have been described in the literature. Phase I consists primarily of sand and small gravel moving at relatively low rates over a stable channel surface....

Hybrid upwind discretization of nonlinear two-phase flow with gravity

NASA Astrophysics Data System (ADS)

Lee, S. H.; Efendiev, Y.; Tchelepi, H. A.

2015-08-01

Multiphase flow in porous media is described by coupled nonlinear mass conservation laws. For immiscible Darcy flow of multiple fluid phases, whereby capillary effects are negligible, the transport equations in the presence of viscous and buoyancy forces are highly nonlinear and hyperbolic. Numerical simulation of multiphase flow processes in heterogeneous formations requires the development of discretization and solution schemes that are able to handle the complex nonlinear dynamics, especially of the saturation evolution, in a reliable and computationally efficient manner. In reservoir simulation practice, single-point upwinding of the flux across an interface between two control volumes (cells) is performed for each fluid phase, whereby the upstream direction is based on the gradient of the phase-potential (pressure plus gravity head). This upwinding scheme, which we refer to as Phase-Potential Upwinding (PPU), is combined with implicit (backward-Euler) time discretization to obtain a Fully Implicit Method (FIM). Even though FIM suffers from numerical dispersion effects, it is widely used in practice. This is because of its unconditional stability and because it yields conservative, monotone numerical solutions. However, FIM is not unconditionally convergent. The convergence difficulties are particularly pronounced when the different immiscible fluid phases switch between co-current and counter-current states as a function of time, or (Newton) iteration. Whether the multiphase flow across an interface (between two control-volumes) is co-current, or counter-current, depends on the local balance between the viscous and buoyancy forces, and how the balance evolves in time. The sensitivity of PPU to small changes in the (local) pressure distribution exacerbates the problem. The common strategy to deal with these difficulties is to cut the timestep and try again. Here, we propose a Hybrid-Upwinding (HU) scheme for the phase fluxes, then HU is combined with implicit time discretization to yield a fully implicit method. In the HU scheme, the phase flux is divided into two parts based on the driving force. The viscous-driven and buoyancy-driven phase fluxes are upwinded differently. Specifically, the viscous flux, which is always co-current, is upwinded based on the direction of the total-velocity. The buoyancy-driven flux across an interface is always counter-current and is upwinded such that the heavier fluid goes downward and the lighter fluid goes upward. We analyze the properties of the Implicit Hybrid Upwinding (IHU) scheme. It is shown that IHU is locally conservative and produces monotone, physically-consistent numerical solutions. The IHU solutions show numerical diffusion levels that are slightly higher than those for standard FIM (i.e., implicit PPU). The primary advantage of the IHU scheme is that the numerical overall-flux of a fluid phase remains continuous and differentiable as the flow regime changes between co-current and counter-current conditions. This is in contrast to the standard phase-potential upwinding scheme, in which the overall fractional-flow (flux) function is non-differentiable across the boundary between co-current and counter-current flows.

Movements of a Sphere Moving Over Smooth and Rough Inclines

NASA Astrophysics Data System (ADS)

Jan, Chyan-Deng

1992-01-01

The steady movements of a sphere over a rough incline in air, and over smooth and rough inclines in a liquid were studied theoretically and experimentally. The principle of energy conservation was used to analyze the translation velocities, rolling resistances, and drag coefficients of a sphere moving over the inclines. The rolling resistance to the movement of a sphere from the rough incline was presumed to be caused by collisions and frictional slidings. A varnished wooden board was placed on the bottom of an experimental tilting flume to form a smooth incline and a layer of spheres identical to the sphere moving over them was placed on the smooth wooden board to form a rough incline. Spheres used in the experiments were glass spheres, steel spheres, and golf balls. Experiments show that a sphere moving over a rough incline with negligible fluid drag in air can reach a constant translation velocity. This constant velocity was found to be proportional to the bed inclination (between 11 ^circ and 21^circ) and the square root of the sphere's diameter, but seemingly independent of the sphere's specific gravity. Two empirical coefficients in the theoretical expression of the sphere's translation velocity were determined by experiments. The collision and friction parts of the shear stress exerted on the interface between the moving sphere and rough incline were determined. The ratio of collision to friction parts appears to increase with increase in the bed inclination. These two parts seem to be of the same order of magnitude. The rolling resistances and the relations between the drag coefficient and Reynolds number for a sphere moving over smooth and rough inclines in a liquid, such as water or salad oil, were determined by a regression analysis based on experimental data. It was found that the drag coefficient for a sphere over the rough incline is larger than that for a sphere over the smooth incline, and both of which are much larger than that for a sphere in free fall. The relative magnitudes of the shear stresses due to drag, collision, and friction were also determined in terms of the Reynolds number.

Forecasting Daily Patient Outflow From a Ward Having No Real-Time Clinical Data

PubMed Central

Tran, Truyen; Luo, Wei; Phung, Dinh; Venkatesh, Svetha

2016-01-01

Background: Modeling patient flow is crucial in understanding resource demand and prioritization. We study patient outflow from an open ward in an Australian hospital, where currently bed allocation is carried out by a manager relying on past experiences and looking at demand. Automatic methods that provide a reasonable estimate of total next-day discharges can aid in efficient bed management. The challenges in building such methods lie in dealing with large amounts of discharge noise introduced by the nonlinear nature of hospital procedures, and the nonavailability of real-time clinical information in wards. Objective Our study investigates different models to forecast the total number of next-day discharges from an open ward having no real-time clinical data. Methods We compared 5 popular regression algorithms to model total next-day discharges: (1) autoregressive integrated moving average (ARIMA), (2) the autoregressive moving average with exogenous variables (ARMAX), (3) k-nearest neighbor regression, (4) random forest regression, and (5) support vector regression. Although the autoregressive integrated moving average model relied on past 3-month discharges, nearest neighbor forecasting used median of similar discharges in the past in estimating next-day discharge. In addition, the ARMAX model used the day of the week and number of patients currently in ward as exogenous variables. For the random forest and support vector regression models, we designed a predictor set of 20 patient features and 88 ward-level features. Results Our data consisted of 12,141 patient visits over 1826 days. Forecasting quality was measured using mean forecast error, mean absolute error, symmetric mean absolute percentage error, and root mean square error. When compared with a moving average prediction model, all 5 models demonstrated superior performance with the random forests achieving 22.7% improvement in mean absolute error, for all days in the year 2014. Conclusions In the absence of clinical information, our study recommends using patient-level and ward-level data in predicting next-day discharges. Random forest and support vector regression models are able to use all available features from such data, resulting in superior performance over traditional autoregressive methods. An intelligent estimate of available beds in wards plays a crucial role in relieving access block in emergency departments. PMID:27444059

Changes in glycolytic enzyme activities in aging erythrocytes fractionated by counter-current distribution in aqueous polymer two-phase systems.

PubMed Central

Jimeno, P; Garcia-Perez, A I; Luque, J; Pinilla, M

1991-01-01

Human and rat erythrocytes were fractionated by counter-current distribution in charge-sensitive dextran/poly(ethylene glycol) two-phase systems. The specific activities of the key glycolytic enzymes (hexokinase, phosphofructokinase and pyruvate kinase) declined along the distribution profiles, although the relative positions of the activity profiles were reversed in the two species. These enzymes maintained their normal response to specific regulatory effectors in all cell fractions. No variations were observed for phosphoglycerate kinase and bisphosphoglycerate mutase activities. Some correlations between enzyme activities (pyruvate kinase/hexokinase, pyruvate kinase/phosphofructokinase, pyruvate kinase/pyruvate kinase plus phosphoglycerate kinase, pyruvate kinase/bisphosphoglycerate mutase and phosphoglycerate kinase/bisphosphoglycerate mutase ratios) were studied in whole erythrocyte populations as well as in cell fractions. These results strongly support the fractionation of human erythrocytes according to cell age, as occurs with rat erythrocytes. PMID:1656939

Preparative isolation and purification of anti-tumor agent ansamitocin P-3 from fermentation broth of Actinosynnema pretiosum using high-performance counter-current chromatography.

PubMed

Yao, Yuqin; Cheng, Zhihui; Ye, Haoyu; Xie, Yongmei; He, Jing; Tang, Minghai; Shen, Tao; Wang, Jiangman; Zhou, Yan; Lu, Zejun; Luo, Feng; Chen, Lijuan; Yu, Luoting; Yang, Jin-Liang; Peng, Aihua; Wei, Yuquan

2010-05-01

Ansamitocin P-3 is a potent anti-tumor maytansinoid found in Actinosynnema pretiosum. However, due to the complexity of the fermentation broth of Actinomycete, how to effectively separate ansamitocin P-3 is still a challenge. In this study, both analytical and preparative high-performance counter-current chromatography were successfully used to separate and purify ansamitocin P-3 from fermentation broth. A total of 28.8 mg ansamitocin P-3 with purity of 98.4% was separated from 160 mg crude sample of fermentation broth in less than 80 min with the two-phase solvent system of hexane-ethyl acetate-methanol-water (0.6:1:0.6:1, v/v/v/v). The purity and structural identification were determined by HPLC, (1)H NMR, (13)C NMR and mass spectroscopy.

Separation of three anthraquinone glycosides including two isomers by preparative high-performance liquid chromatography and high-speed countercurrent chromatography from Rheum tanguticum Maxim. ex Balf.

PubMed

Chen, Tao; Li, Hongmei; Zou, Denglang; Liu, Yongling; Chen, Chen; Zhou, Guoying; Li, Yulin

2016-08-01

Anthraquinone glycosides, such as chrysophanol 1-O-β-d-glucoside, chrysophanol 8-O-β-d-glucoside, and physion 8-O-β-d-glucoside, are the accepted important active components of Rheum tanguticum Maxim. ex Balf. due to their pharmacological properties: antifungal, antimicrobial, cytotoxic, and antioxidant activities. However, an effective method for the separation of the above-mentioned anthraquinone glycosides from this herb is not currently available. Especially, greater difficulty existed in the separation of the two isomers chrysophanol 1-O-β-d-glucoside and chrysophanol 8-O-β-d-glucoside. This study demonstrated an efficient strategy based on preparative high-performance liquid chromatography and high-speed countercurrent chromatography for the separation of the above-mentioned anthraquinone glycosides from Rheum tanguticum Maxim.ex Balf. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ELM-free and inter-ELM divertor heat flux broadening induced by edge harmonics oscillation in NSTX

DOE PAGES

Gan, K. F.; Ahn, J. -W.; Gray, T. K.; ...

2017-10-26

A new n =1 dominated edge harmonic oscillation (EHO) has been found in NSTX. The new EHO, rotating toroidally in the counter-current direction and the opposite direction of the neutral beam, was observed during certain inter-ELM and ELM-free periods of H-mode operation. This EHO is associated with a significant broadening of the integral heat flux width (more » $${{\\lambda}_{\\operatorname{int}}}$$ ) by up to 150%, and a decrease in the divertor peak heat flux by >60%. An EHO induced filament was also observed by the gas puff imaging diagnostic. The toroidal rotating filaments could change the edge magnetic topology resulting in toroidal rotating strike point splitting and heat flux broadening. Finally, experimental result of the counter current rotation of strike points splitting is consistent with the counter-current EHO.« less

Separation of two major chalcones from Angelica keiskei by high-speed counter-current chromatography.

PubMed

Kil, Yun-Seo; Nam, Joo-Won; Lee, Jun; Seo, Eun Kyoung

2015-08-01

Angelica keiskei (Shin-sun cho) is an edible higher plant with the beneficial preventive effects on cancer, hypertension, and coronary heart disease. Two bioactive chalcones of Shin-sun cho, xanthoangelol (1) and 4-hydroxyderricin (2), were separated simultaneously by using high-speed counter-current chromatography with a two-phase solvent system composed of n-hexane-EtOAc-MeOH-H2O (9:5:9:4). Only nonconsuming processes, solvent fractionations and Sephadex LH-20 column chromatography, were conducted as presteps. Xanthoangelol (1, 35.9 mg, 99.9 % purity at 254 and 365 nm) and 4-hydroxyderricin (2, 4.4 mg, 98.7 % purity at 254 nm and 98.8 % purity at 365 nm) were successfully purified from 70 mg of the processed extract from A. keiskei. The structures of two compounds were confirmed by (1)H- and (13)C-NMR analysis.

An interesting two-phase solvent system and its use in preparative isolation of aconitines from aconite roots by counter-current chromatography.

PubMed

Han, Quan-Bin; Tang, Wai-Lun; Dong, Cai-Xia; Xu, Hong-Xi; Jiang, Zhi-Hong

2013-04-01

Two-phase solvent system plays crucial role in successful separation of organic compounds using counter-current chromatography (CCC). An interesting two-phase solvent system, composed of chloroform/ethyl acetate/methanol/water, is reported here, in which both phases contain sufficient organic solvents to balance their dissolving capacities. Adjusting the solvent system to get satisfactory partition coefficients (K values) for target compounds becomes relatively simple. This solvent system succeeded in sample preparation of aconitine (8.07 mg, 93.69%), hypaconitine (7.74 mg, 93.17%), mesaconitine (1.95 mg, 94.52%) from raw aconite roots (102.24 mg, crude extract), benzoylmesaconine (34.79 mg, 98.67%) from processed aconite roots (400.01 mg, crude extract), and yunaconitine (253.59 mg, 98.65%) from a crude extract of Aconitum forrestii (326.69 mg, crude extract). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A numerical world ocean general circulation model Part I. Basic design and barotropic experiment

NASA Astrophysics Data System (ADS)

Han, Young-June

1984-08-01

A new six-layer world ocean general circulation model based on the primitive system of equations is described in detail and its performance in the case of a homogeneous ocean is described. These test integrations show that the model is capable of reproducing the observed mean barotropic or vertically-integrated transport, as well as the seasonal variability of the major ocean gyres. The surface currents, however, are dominated by the Ekman transport, and such non-linear features as the western boundary currents and the equatorial countercurrents are poorly represented. The abyssal boundary countercurrents are also absent due to the lack of thermohaline forcing. The most conspicuous effect of the bottom topography on a homogeneous ocean is seen in the Southern ocean where the calculated Antarctic circumpolar transport through the Drake passage ( ≈ 10 Sv, with bathymetry included) greatly underestimates the observed transport (≈ 100 Sv).

New analytical spiral tube assembly for separation of proteins by counter-current chromatography.

PubMed

Ma, Xiaofeng; Ito, Yoichiro

2015-07-31

A new spiral column assembly for analytical separation by counter-current chromatography is described. The column is made from a plastic spiral tube support which has 12 interwoven spiral grooves. The PTFE tubing of 1.6mm ID was first flattened by extruding through a narrow slit and inserted into the grooves to make 5 spiral layers with about 60ml capacity. The performance of the spiral column assembly was tested with separation of three stable protein samples including cytochrome C, myoglobin and lysozyme in a polymer phase system composed of polyethylene glycol 1000 and dibasic potassium phosphate each at 12.5% (w/w) in water. At 2ml/min, three protein samples were well resolved in 1h. The separation time may be further shortened by application of higher revolution speed and flow rate by improving the strength of the spiral tube support in the future. Published by Elsevier B.V.

ISOLATION OF GLYCOSIDES FROM THE BARKS OF ILEX ROTUNDA BY HIGH-SPEED COUNTER-CURRENT CHROMATOGRAPHY.

PubMed

Wang, Chun; Chao, Zhimao; Sun, Wen; Wu, Xiaoyi; Ito, Yoichiro

2014-04-01

Semi-preparative and preparative high-speed counter-current chromatography (HSCCC) were successfully used for isolation of glycosides from 50% ethanol extract of the dried barks of Ilex rotunda Thunb. (Aquifoliaceae) by using a two-phase solvent system composed of ethyl acetate-n-butanol-water (1:6:7, v/v/v). From 1.0 g of the extract, syringaresinol 4',4"-di-o-β-d-glucopyranoside ( I , 20.2 mg),, syringin ( II , 56.8 mg), sinapaldehyde glucoside ( III , 26.2 mg),, syringaresinol 4'-o-β-d-glucopyranoside ( IV , 20.4 mg), and pedunculoside ( V , 45.1 mg) were obtained by one run of TBE-1000A HSCCC instrument with 1000 mL of column volume. Their structures were identified by IR, MS, and 1 H and 13 C NMR studies. Glycoside I was isolated from this plant for the first time.

ISOLATION OF GLYCOSIDES FROM THE BARKS OF ILEX ROTUNDA BY HIGH-SPEED COUNTER-CURRENT CHROMATOGRAPHY

PubMed Central

Wang, Chun; Chao, Zhimao; Sun, Wen; Wu, Xiaoyi; Ito, Yoichiro

2013-01-01

Semi-preparative and preparative high-speed counter-current chromatography (HSCCC) were successfully used for isolation of glycosides from 50% ethanol extract of the dried barks of Ilex rotunda Thunb. (Aquifoliaceae) by using a two-phase solvent system composed of ethyl acetate-n-butanol-water (1:6:7, v/v/v). From 1.0 g of the extract, syringaresinol 4',4"-di-o-β-d-glucopyranoside (I, 20.2 mg),, syringin (II, 56.8 mg), sinapaldehyde glucoside (III, 26.2 mg),, syringaresinol 4'-o-β-d-glucopyranoside (IV, 20.4 mg), and pedunculoside (V, 45.1 mg) were obtained by one run of TBE-1000A HSCCC instrument with 1000 mL of column volume. Their structures were identified by IR, MS, and 1H and 13C NMR studies. Glycoside I was isolated from this plant for the first time. PMID:25132792

Countercurrent direct contact heat exchange process and system

DOEpatents

Wahl, III, Edward F.; Boucher, Frederic B.

1979-01-01

Recovery of energy from geothermal brines and other hot water sources by direct contact heat exchange with a working fluid, such as a hydrocarbon working fluid, e.g. isobutane. The process and system consists of a plurality of stages, each stage including mixing and settling units. In the first stage, hot brine and arm working fluid are intimately mixed and passed into a settler wherein the brine settles to the bottom of the settler and the hot working fluid rises to the top. The hot working fluid is passed to a heat engine or turbine to produce work and the working fluid is then recycled back into the system. The system is comprised of a series of stages each containing a settler and mixer, and wherein the working fluid and the brine flow in a countercurrent manner through the stages to recover the heat from the brine in increments and raise the temperature of the working fluid in increments.

Application of silver ion in the separation of macrolide antibiotic components by high-speed counter-current chromatography.

PubMed

Wen, Yaoming; Wang, Jiaoyan; Chen, Xiuming; Le, Zhanxian; Chen, Yuxiang; Zheng, Wei

2009-05-29

Three macrolide antibiotic components - ascomycin, tacrolimus and dihydrotacrolimus - were separated and purified by silver ion high-speed counter-current chromatography (HSCCC). The solvent system consisted of n-hexane-tert-butyl methyl ether-methanol-water (1:3:6:5, v/v) and silver nitrate (0.10mol/l). The silver ion acted as a pi-complexing agent with tacrolimus because of its extra side double bond compared with ascomycin and dihydrotacrolimus. This complexation modified the partition coefficient values and the separation factors of the three components. As a result, ascomycin, tacrolimus and dihydrotacrolimus were purified from 150mg extracted crude sample with purities of 97.6%, 98.7% and 96.5%, respectively, and yields over 80% (including their tautomers). These results cannot be achieved with the same solvent system but without the addition of silver ion.

Preparative isolation and purification of chemical constituents from the root of Adenophora tetraphlla by high-speed counter-current chromatography with evaporative light scattering detection.

PubMed

Yao, Shun; Liu, Renming; Huang, Xuefeng; Kong, Lingyi

2007-01-19

Preparative high-speed counter-current chromatography (HSCCC), as a continuous liquid-liquid partition chromatography with no solid support matrix, combined with evaporative light scattering detection (ELSD) was employed for systematic separation and purification of non-chromophoric chemical components from Chinese medicinal herb Adenophora tetraphlla (Thunb.), Fisch. Nine compounds, including alpha-spinasterol, beta-sitosterol, nonacosan-10-ol, 24-methylene cycloartanol, lupenone, 3-O-palmitoyl-beta-sitosterol, 3-O-beta-d-glucose-beta-sitosterol, eicosanoic acid and an unknown compound, were obtained. The compounds were all above 95% determined by high-performance liquid chromatography (HPLC)-ELSD, and their structures were identified by (1)H NMR and chemical ionization mass spectroscopy (CI-MS). The results demonstrate that HSCCC coupled with ELSD is a feasible and efficient technique for systematic isolation of non-chromophoric components from traditional medicinal herbs.

Isolation and Purification of Two Isoflavones from Hericium erinaceum Mycelium by High-Speed Counter-Current Chromatography.

PubMed

He, Jinzhe; Fan, Peng; Feng, Simin; Shao, Ping; Sun, Peilong

2018-03-02

High-speed counter-current chromatography (HSCCC) was used to separate and purify two isoflavones for the first time from Hericium erinaceum ( H. erinaceum ) mycelium using a two-phase solvent system composed of chloroform-dichloromethane-methanol-water (4:2:3:2, v / v / v / v ). These two isoflavones were identified as genistein (4',5,7-trihydroxyisoflavone, C 15 H 10 O₅) and daidzein (4',7-dihydroxyisoflavone, C 15 H 10 O₄), using infrared spectroscopy (IR), electro-spary ionisation mass (ESI-MS), ¹H-nuclear magnetic resonance (NMR) and 13 C-NMR spectra. About 23 mg genistein with 95.7% purity and 18 mg daidzein with 97.3% purity were isolated from 150 mg ethanolic extract of H. erinaceum mycelium. The results demonstrated that HSCCC was a feasible method to separate and purify genistein and daidzein from H. erinaceum mycelium.

Complex proximal deposition during the Plinian eruptions of 1912 at Novarupta, Alaska

USGS Publications Warehouse

Houghton, Bruce F.; Wilson, C.J.N.; Fierstein, J.; Hildreth, W.

2004-01-01

Proximal (<3 km) deposits from episodes II and III of the 60-h-long Novarupta 1912 eruption exhibit a very complex stratigraphy, the result of at least four transport regimes and diverse depositional mechanisms. They contrast with the relatively simple stratigraphy (and inferred emplacement mechanisms) for the previously documented, better known, medial-distal fall deposits and the Valley of Ten Thousand Smokes ignimbrite. The proximal products include alternations and mixtures of both locally and regionally dispersed fall ejecta, and numerous thin complex deposits of pyroclastic density currents (PDCs) with no regional analogs. The locally dispersed component of the fall deposits forms sector-confined wedges of material whose thicknesses halve radially from and concentrically about the vent over distances of 100-300 m (cf. several kilometers for the medial-distal fall deposits). This locally dispersed fall material (and many of the associated PDC deposits) is rich in andesitic and banded pumices and richer in shallow-derived wall-rock lithics in comparison with the coeval medial fall units of almost entirely dacitic composition. There are no marked contrasts in grain size in the near-vent deposits, however, between locally and widely dispersed beds, and all samples of the proximal fall deposits plot as a simple continuation of grain size trends for medial-distal samples. Associated PDC deposits form a spectrum of facies from fines-poor, avalanched beds through thin-bedded, landscape-mantling beds to channelized lobes of pumice-block-rich ignimbrite. The origins of the Novarupta near-vent deposits are considered within a spectrum of four transport regimes: (1) sustained buoyant plume, (2) fountaining with co-current flow, (3) fountaining with counter-current flow, and (4) direct lateral ejection. The Novarupta deposits suggest a model where buoyant, stable, regime-1 plumes characterized most of episodes II and III, but were accompanied by transient and variable partitioning of clasts into the other three regimes. Only one short period of vent blockage and cessation of the Plinian plume occurred, separating episodes II and III, which was followed by a single PDC interpreted as an overpressured "blast" involving direct lateral ejection. In contrast, regimes 2 and 3 were reflected by spasmodic sedimentation from the margins of the jet and perhaps lower plume, which were being strongly affected by short-lived instabilities. These instabilities in turn are inferred to be associated with heterogeneities in the mixture of gas and pyroclasts emerging from the vent. Of the parameters that control explosive eruptive behavior, only such sudden and asymmetrical changes in the particle concentration could operate on time scales sufficiently short to explain the rapid changes in the proximal 1912 products. ?? Springer-Verlag 2003.

Three-dimensional flow structure and patterns of bed shear stress in an evolving compound meander bend

USGS Publications Warehouse

Engel, Frank; Rhoads, Bruce L.

2016-01-01

Compound meander bends with multiple lobes of maximum curvature are common in actively evolving lowland rivers. Interaction among spatial patterns of mean flow, turbulence, bed morphology, bank failures and channel migration in compound bends is poorly understood. In this paper, acoustic Doppler current profiler (ADCP) measurements of the three-dimensional (3D) flow velocities in a compound bend are examined to evaluate the influence of channel curvature and hydrologic variability on the structure of flow within the bend. Flow structure at various flow stages is related to changes in bed morphology over the study timeframe. Increases in local curvature within the upstream lobe of the bend reduce outer bank velocities at morphologically significant flows, creating a region that protects the bank from high momentum flow and high bed shear stresses. The dimensionless radius of curvature in the upstream lobe is one-third less than that of the downstream lobe, with average bank erosion rates less than half of the erosion rates for the downstream lobe. Higher bank erosion rates within the downstream lobe correspond to the shift in a core of high velocity and bed shear stresses toward the outer bank as flow moves through the two lobes. These erosion patterns provide a mechanism for continued migration of the downstream lobe in the near future. Bed material size distributions within the bend correspond to spatial patterns of bed shear stress magnitudes, indicating that bed material sorting within the bend is governed by bed shear stress. Results suggest that patterns of flow, sediment entrainment, and planform evolution in compound meander bends are more complex than in simple meander bends. Moreover, interactions among local influences on the flow, such as woody debris, local topographic steering, and locally high curvature, tend to cause compound bends to evolve toward increasing planform complexity over time rather than stable configurations.

Capture of a recombinant protein from unclarified canola extract using streamline expanded bed anion exchange.

PubMed

Bai, Yun; Glatz, Charles E

2003-03-30

The feasibility of applying expanded bed adsorption technology to recombinant protein recovery from extracts of transgenic canola (rapeseed) was assessed. The extraction step results in a suspension of high solids content that is difficult to clarify. The coarse portion of the solids can be removed easily, and our aim was to operate the expanded bed in the presence of the recalcitrant particulates. Recombinant beta-glucuronidase (rGUS) produced in transgenic canola seed was the model system. Diethylaminoethyl (DEAE) and Streamline DEAE resin exhibited similar binding and elution properties for both rGUS and native canola proteins. More than 95% of native canola proteins did not bind to DEAE resins at pH 7.5, whereas the bound proteins were fractionated by two-step salt elution into two groups with the first peak, containing 70% of total bound proteins, at 20 mS/cm, followed by elution of rGUS at 50 mS/cm. The adsorption isotherm was only slightly influenced by the presence of up to 14 mg solids/mL extract; C(m) and K(d) changed by -1% and +39%, respectively. Bed expansion was semiquantitatively predictable from physical properties of the fluid together with Stokes's law and the Richardson-Zaki correlation for both clarified and partially clarified extracts. The presence of 1.4% solids did not change rGUS breakthrough behavior of the expanded bed; however, a small difference between expanded bed and packed bed was observed early in the sample loading stage, during which bed expansion adjusts. Canola solids moved through the column in approximately plug flow with no detriment to bed stability. Seventy-two percent recovery of 34-fold purified rGUS was obtained after initial loading of 1.4% (w/w) solids extract to 25% breakthrough. Copyright 2003 Wiley Periodicals, Inc. Biotechnol Bioeng 81: 855-864, 2003.

KSC-07pd0851

NASA Image and Video Library

2007-04-10

KENNEDY SPACE CENTER, FLA. -- Two trucks (one air-ride, one flat-bed) deliver the Dawn spacecraft, as well as additional electrical and ground support equipment and xenon ground support equipment, to Astrotech. Dawn will be moved from the truck and the shipping container removed. The spacecraft will then be moved into the high bay of the Payload Processing Facility. Dawn's mission is to explore two of the asteroid belt's most intriguing and dissimilar occupants: asteroid Vesta and the dwarf planet Ceres. The Dawn mission is managed by JPL, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate in Washington, D.C. Photo credit: NASA/Jim Grossmann

PH-zone-refining counter-current chromatography with a hydrophilic organic/salt-containing two-phase solvent system for preparative separation of polar alkaloids from natural products.

PubMed

Zou, Denglang; Du, Yurong; Kuang, Jianyuan; Sun, Shihao; Ma, Jianbin; Jiang, Renwang

2018-06-08

This study presents an efficient strategy based on pH-zone-refining counter-current chromatography with a hydrophilic organic/salt-containing two-phase system composed of acetonitrile, sodium chloride and water for preparative separation of polar alkaloids from natural products. Acetonitrile-sodium chloride-water system provides a wider range of polarity for polar alkaloids than classical aqueous two-phase systems. It gets rid of the effect of free hydrogen ion, strong ionic strength, hold low viscosity and the sharp retainer border could be formed easily. So acetonitrile-sodium chloride-water system showed great advantages to pH-zone-refining counter-current chromatography for polar alkaloids. The separation of polar indole alkaloids from toad venom was selected as an example to show the advantage and practicability of this strategy. An optimized acetonitrile-sodium chloride-water (54%:5%:41%, w%) system was applied in this study, where 10 mM triethylamine (TEA) as the retainer and 15 mM hydrochloric acid (HCl) as the eluter were added. As a result, three polar indole alkaloids, including 19 mg of serotonin, 45 mg of 5-Hydroxy-N'-methyl tryptamine, 33 mg of bufotenine were simultaneously separated from 500 mg of 5% ethanol elution fraction of toad venom on macroporous resin chromatography, with the purity of 91.3%, 97.5% and 89.4%, respectively. Their structures were identified by spectroscopic analysis. Copyright © 2018 Elsevier B.V. All rights reserved.

Magnetic nanoparticles and high-speed countercurrent chromatography coupled in-line and using the same solvent system for separation of quercetin-3-O-rutinoside, luteoloside and astragalin from a Mikania micrantha extract.

PubMed

Wang, Juanqiang; Geng, Shan; Wang, Binghai; Shao, Qian; Fang, Yingtong; Wei, Yun

2017-07-28

A new in-line method of magnetic nanoparticles (MNPs) coupled with high-speed countercurrent chromatography (HSCCC) using a same solvent system during the whole separation process was established to achieve the rapid separation of flavonoids from Mikania micrantha. The adsorption and desorption capacities of five different MNPs for flavonoid standards and Mikania micrantha crude extract were compared and the most suitable magnetic nanoparticle Fe 3 O 4 @SiO 2 @DIH@EMIMLpro was selected as the in-line MNP column. An in-line separation system was established by combining this MNP column with HSCCC through a six-way valve. The comparison between two solvent systems n-hexane-ethyl acetate-methanol-water (3:5:3:5, v/v) and ethyl acetate-methanol-water (25:1:25, v/v) showed that the latter solvent system was more suitable for simultaneously in-line separating three flavonoids quercetin-3-O-rutinoside, luteoloside and astragalin from Mikania micrantha. The purities of these three compounds with the ethyl acetate-methanol-water solvent system were 95.13%, 98.54% and 98.19% respectively. Results showed the established in-line separation system of MNP-HSCCC was efficient, recyclable and served to isolate potential flavonoids with similar polarities from natural complex mixtures. The in-line combination of magnetic nanoparticles with high-speed countercurrent chromatography eluting with the same solvent system during the whole separation process was established for the first time. Copyright © 2017 Elsevier B.V. All rights reserved.

Target-guided separation of Bougainvillea glabra betacyanins by direct coupling of preparative ion-pair high-speed countercurrent chromatography and electrospray ionization mass-spectrometry.

PubMed

Jerz, Gerold; Wybraniec, Sławomir; Gebers, Nadine; Winterhalter, Peter

2010-07-02

In this study, preparative ion-pair high-speed countercurrent chromatography was directly coupled to an electrospray ionization mass-spectrometry device (IP-HSCCC/ESI-MS-MS) for target-guided fractionation of high molecular weight acyl-oligosaccharide linked betacyanins from purple bracts of Bougainvillea glabra (Nyctaginaceae). The direct identification of six principal acyl-oligosaccharide linked betacyanins in the mass range between m/z 859 and m/z 1359 was achieved by positive ESI-MS ionization and gave access to the genuine pigment profile already during the proceeding of the preparative separation. Inclusively, all MS/MS-fragmentation data were provided during the chromatographic run for a complete analysis of substitution pattern. On-line purity evaluation of the recovered fractions is of high value in target-guided screening procedures and for immediate decisions about suitable fractions used for further structural analysis. The applied preparative hyphenation was shown to be a versatile screening method for on-line monitoring of countercurrent chromatographic separations of polar crude pigment extracts and also traced some minor concentrated compounds. For the separation of 760mg crude pigment extract the biphasic solvent system tert.-butylmethylether/n-butanol/acetonitrile/water 2:2:1:5 (v/v/v/v) was used with addition of ion-pair forming reagent trifluoroacetic acid. The preparative HSCCC-eluate had to be modified by post-column addition of a make-up solvent stream containing formic acid to reduce ion-suppression caused by trifluoroacetic acid and later significantly maximized response of ESI-MS/MS detection of target substances. A variable low-pressure split-unit guided a micro-eluate to the ESI-MS-interface for sensitive and direct on-line detection, and the major volume of the effluent stream was directed to the fraction collector for preparative sample recovery. The applied make-up solvent mixture significantly improved smoothness of the continuously measured IP-HSCCC-ESI-MS base peak ion trace in the experimental range of m/z 50-2200 by masking stationary phase bleeding and generating a stable single solvent phase for ESI-MS/MS detection. Immediate structural data were retrieved throughout the countercurrent chromatography run containing complete MS/MS-fragmentation pattern of the separated acyl-substituted betanidin oligoglycosides. Single ion monitoring indicated clearly the base-line separation of higher concentrated acylated betacyanin components. Copyright 2010 Elsevier B.V. All rights reserved.

Moving Bed Granular Bed Filter Development Program. Topical report, September 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haas, J.C.; Prudhomme, J.W.; Wilson, K.W.

1994-09-01

Five test arrangements have been designed to support the Granular Bed Filter Development Program as defined in the Test Plan. The first arrangement is a 3.6 ft. diameter half filter, with a glass covering along the cross section to allow visual examination of the granular alumina material passing through the filter. The second test arrangement is a 3.6 ft diameter full size filter having refractory lining to simulate actual surface roughness conditions. The third test arrangement will examine filter geometry scale up by testing a 6.0 ft. diameter full size filter. The fourth Test Arrangement consists of a small 12more » inch diameter fluidizer to measure the minimum fluidization velocity of the 7 m (approx. size) alumina material to be used in the filter assemblies. The last Test Unit is used to evaluation relative abrasion characteristics of potential refractory and ceramic materials to be installed in high abrasion areas in the pneumatic transport piping.« less

CFD modelling of liquid-solid transport in the horizontal eccentric annuli

NASA Astrophysics Data System (ADS)

Sayindla, Sneha; Challabotla, Niranjan Reddy

2017-11-01

In oil and gas drilling operations, different types of drilling fluids are used to transport the solid cuttings in an annulus between drill pipe and well casing. The inner pipe is often eccentric and flow inside the annulus can be laminar or turbulent regime. In the present work, Eulerian-Eulerian granular multiphase CFD model is developed to systematically investigate the effect of the rheology of the drilling fluid type (Newtonian and non-Newtonian), drill pipe eccentricity and inner pipe rotation on the efficiency of cuttings transport. Both laminar and turbulent flow regimes were considered. Frictional pressure drop is computed and compared with the flow loop experimental results reported in the literature. The results confirm that the annular frictional pressure loss in a fully eccentric annulus are significantly lesser than the concentric annulus. Inner pipe rotation improve the efficiency of the cuttings transport in laminar flow regime. Cuttings transport velocity and concentration distribution were analysed to predict the different flow patterns such as stationary bed, moving bed, heterogeneous and homogeneous bed formation.

Process for gasifying carbonaceous material from a recycled condensate slurry

DOEpatents

Forney, Albert J.; Haynes, William P.

1981-01-01

Coal or other carbonaceous material is gasified by reaction with steam and oxygen in a manner to minimize the problems of effluent water stream disposal. The condensate water from the product gas is recycled to slurry the coal feed and the amount of additional water or steam added for cooling or heating is minimized and preferably kept to a level of about that required to react with the carbonaceous material in the gasification reaction. The gasification is performed in a pressurized fluidized bed with the coal fed in a water slurry and preheated or vaporized by indirect heat exchange contact with product gas and recycled steam. The carbonaceous material is conveyed in a gas-solid mixture from bottom to top of the pressurized fluidized bed gasifier with the solids removed from the product gas and recycled steam in a supported moving bed filter of the resulting carbonaceous char. Steam is condensed from the product gas and the condensate recycled to form a slurry with the feed coal carbonaceous particles.

Fixed Bed Column Study for Adsolubilization of 2,4-D Herbicide on Surfactant Modified Silica Gel Waste

NASA Astrophysics Data System (ADS)

Koner, S.; Adak, A.

2012-09-01

The fixed bed column study was conducted for the removal of 2,4-dichlorophenoxyacetic acid (2,4-D), a widely used herbicide from synthetically prepared wastewater using surfactant modified silica gel waste (SMSGW) as an adsorbing media. The adsorbing media was prepared by treating silica gel waste (SGW) with cationic surfactant. The removal was due to adsolubilization of 2,4-D molecules within the admicelles formed on the surface of SGW. The column having 2.5 cm diameter, with different bed heights such as 20, 30 and 40 cm were used in the study. The different column design parameters like depth of exchange zone, time required for exchange zone to move its own height, adsorption rate constant, adsorption capacity constant were calculated using BDST model. The SMSGW was found to be a very efficient media for the removal of 2,4-D from wastewater. Column design parameters were modeled for different field conditions to predict the duration of column run for practical application.

A Smart Home Test Bed for Undergraduate Education to Bridge the Curriculum Gap from Traditional Power Systems to Modernized Smart Grids

ERIC Educational Resources Information Center

Hu, Qinran; Li, Fangxing; Chen, Chien-fei

2015-01-01

There is a worldwide trend to modernize old power grid infrastructures to form future smart grids, which will achieve efficient, flexible energy consumption by using the latest technologies in communication, computing, and control. Smart grid initiatives are moving power systems curricula toward smart grids. Although the components of smart grids…

Nondestructive Quantitative Sampling for Freshwater Mussels in Variable Substrate Streams

Treesearch

John B. Richardson; Winston Paul Smith

1994-01-01

Unionidmussels were sampled in the Big South Fork of the Cumberland River, Tennessee and Kentucky, from July to October 1988 with a chain grid of10 l-m2 quadrats. The chain grid was used to define 100-m2 areas along the stream bed by repeatedly moving the10-m2 rectangle upstream. Within each100-m

Illustrative Experiments of the Erosion of Sand and Accompanying Theoretical Considerations

ERIC Educational Resources Information Center

Schneiderbauer, Simon

2012-01-01

Winds in desert regions form the well-known barchan dunes. Frequently, human settlements are threatened by the migration of these dunes. But why do these dunes move? And how is dune migration in deserts connected to scour development in the vicinity of pylons in river beds or to snow cornices in alpine regions? This paper introduces the topic of…

Laying hen performance and well-being over two flock cycles on different litter substrates in an aviary housing

USDA-ARS?s Scientific Manuscript database

The momentum to move toward aviary housing has continued to increase in the past eight months. The pressure to find consistent bedding sources for meat birds may impact litter substrate for the laying hen industry as the number of cage-free hens increases in the next nine years. Molting laying hens ...

Intermittent simulated moving bed chromatography: 3. Separation of Tröger's base enantiomers under nonlinear conditions.

PubMed

Katsuo, Shigeharu; Langel, Christian; Sandré, Anne-Laure; Mazzotti, Marco

2011-12-30

One of the modified simulated moving bed (SMB) processes, the intermittent SMB (I-SMB) process, has been recently analyzed theoretically [1] and its superior performance compared to the conventional SMB process has been demonstrated at a rather low total feed concentration through experiments and simulations [2]. This work shows that the I-SMB process outperforms the conventional SMB process also at high feed concentration where the species are clearly subject to a nonlinear adsorption isotherm. In the case of the separation of the Tröger's base's enantiomers in ethanol on ChiralPak AD, the two processes operated in a six-column 1-2-2-1 configuration (one column in sections 1 and 4 and two columns in sections 2 and 3) and in a four-column 1-1-1-1 configuration (one column in each section) are compared at high feed concentration through both experiments and simulations. Even under nonlinear conditions the four column I-SMB process can successfully separate the two enantiomers achieving purity levels as high as the two six column processes and exhibiting better productivity. Copyright © 2011 Elsevier B.V. All rights reserved.

Valorisation of waste tyre by pyrolysis in a moving bed reactor.

PubMed

Aylón, E; Fernández-Colino, A; Murillo, R; Navarro, M V; García, T; Mastral, A M

2010-07-01

The aim of this work is to assess the behaviour of a moving bed reactor, based on a screw transporter design, in waste tyre pyrolysis under several experimental conditions. Waste tyre represents a significant problem in developed countries and it is necessary to develop new technology that could easily process big amounts of this potentially raw material. In this work, the influence of the main pyrolysis process variables (temperature, solid residence time, mass flow rate and inert gas flow) has been studied by a thorough analysis of product yields and properties. It has been found that regardless the process operational parameters, a total waste tyre devolatilisation is achieved, producing a pyrolytic carbon black with a volatile matter content under 5 wt.%. In addition, it has been proven that, in the range studied, the most influencing process variables are temperature and solid mass flow rate, mainly because both variables modify the gas residence time inside the reactor. In addition, it has been found that the modification of these variables affects to the chemical properties of the products. This fact is mainly associated to the different cracking reaction of the primary pyrolysis products. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Valorisation of waste tyre by pyrolysis in a moving bed reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aylon, E.; Fernandez-Colino, A.; Murillo, R., E-mail: ramonm@icb.csic.e

2010-07-15

The aim of this work is to assess the behaviour of a moving bed reactor, based on a screw transporter design, in waste tyre pyrolysis under several experimental conditions. Waste tyre represents a significant problem in developed countries and it is necessary to develop new technology that could easily process big amounts of this potentially raw material. In this work, the influence of the main pyrolysis process variables (temperature, solid residence time, mass flow rate and inert gas flow) has been studied by a thorough analysis of product yields and properties. It has been found that regardless the process operationalmore » parameters, a total waste tyre devolatilisation is achieved, producing a pyrolytic carbon black with a volatile matter content under 5 wt.%. In addition, it has been proven that, in the range studied, the most influencing process variables are temperature and solid mass flow rate, mainly because both variables modify the gas residence time inside the reactor. In addition, it has been found that the modification of these variables affects to the chemical properties of the products. This fact is mainly associated to the different cracking reaction of the primary pyrolysis products.« less

The use of moving bed bio-reactor to laundry wastewater treatment

NASA Astrophysics Data System (ADS)

Bering, Sławomira; Mazur, Jacek; Tarnowski, Krzysztof; Janus, Magdalena; Mozia, Sylwia; Waldemar Morawski, Antoni

2017-11-01

Large laboratory scale biological treatment test of industrial real wastewater, generated in industrial big laundry, has been conducted in the period of May 2016-August 2016. The research aimed at selection of laundry wastewater treatment technology included tests of two-stage Moving Bed Bio Reactor (MBBR), with two reactors filled with carriers Kaldnes K5 (specific area - 800 m2/m3), have been realized in aerobic condition. Operating on site, in the laundry, reactors have been fed real wastewater from laundry retention tank. To the laundry wastewater, contained mainly surfactants and impurities originating from washed fabrics, a solution of urea to supplement nitrogen content and a solution of acid to correct pH have been added. Daily flow of raw wastewater Qd was equal to 0.6-0.8 m3/d. The values of determined wastewater quality indicators showed that substantial decrease of pollutants content have been reached: BOD5 by 94.7-98.1%, COD by 86.9-93.5%, the sum of anionic and nonionic surfactants by 98.7-99.8%. The quality of the purified wastewater, after star-up period, meets the legal requirements regarding the standards for wastewater discharged to the environment.

Microbial community composition of a multi-stage moving bed biofilm reactor and its interaction with kinetic model parameters estimation.

PubMed

Wang, Xiaodong; Bi, Xuejun; Hem, Lars John; Ratnaweera, Harsha

2018-07-15

Microbial community diversity determines the function of each chamber of multi-stage moving bed biofilm reactor (MBBR) systems. How the microbial community data can be further used to serve wastewater treatment process modelling and optimization has been rarely studied. In this study, a MBBR system was set up to investigate the microbial community diversity of biofilm in each functional chamber. The compositions of microbial community of biofilm from different chambers of MBBR were quantified by high-throughput sequencing. Significantly higher proportion of autotrophs were found in the second aerobic chamber (15.4%), while 4.3% autotrophs were found in the first aerobic chamber. Autotrophs in anoxic chamber were negligible. Moreover, ratios of active heterotrophic biomass and autotrophic biomass (X H /X A ) were obtained by performing respiration tests. By setting heterotroph/autotroph ratios obtained from sequencing analysis equal to X H /X A , a novel approach for kinetic model parameters estimation was developed. This work not only investigated microbial community of MBBR system, but also it provided an approach to make further use of molecular microbiology analysis results. Copyright © 2018 Elsevier Ltd. All rights reserved.

Evaluating a strategy for maintaining nitrifier activity during long-term starvation in a moving bed biofilm reactor (MBBR) treating reverse osmosis concentrate.

PubMed

Ye, Liu; Hu, Shihu; Poussade, Yvan; Keller, Jurg; Yuan, Zhiguo

2012-01-01

A two-stage moving bed biofilm reactor (MBBR) was applied at the Bundamba advanced water treatment plant (AWTP) (Queensland, Australia) to treat the reverse osmosis concentrate (ROC) for inorganic nutrient removal. One of the operational challenges for the system was to cope with the large fluctuations of the ROC flow. This study investigated the decay rates of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) and biofilm detachment in MBBR during starvation for up to one month. An intermittent aeration strategy of 15 min aeration every 6 h was applied. This study also evaluated the activity recovery of both AOB and NOB after normal operation was resumed. The results showed that the activity loss of AOB and NOB was relatively minor (<20%) within 10 days of starvation, which ensured relatively quick recovery of ammonium removal when normal operation resumed. In contrast, the AOB and NOB activity loss reached 60-80% when the starvation time was longer than 20 days, resulting in slower recovery of ammonium removal after starvation. Starvation for less than 20 days didn't result in an apparent biomass detachment from carriers.

The application of moving bed bio-reactor (MBBR) in commercial laundry wastewater treatment.

PubMed

Bering, Sławomira; Mazur, Jacek; Tarnowski, Krzysztof; Janus, Magdalena; Mozia, Sylwia; Morawski, Antoni Waldemar

2018-06-15

Large, laboratory scale biological treatment tests of real industrial wastewater, generated in a large industrial laundry facility, was conducted from October 2014 to January 2015. This research sought to develop laundry wastewater treatment technology which included tests of a two-stage Moving Bed Bio Reactor (MBBR); this had two reactors, was filled with carriers Kaldnes K5 (specific area - 800 m 2 /m 3 ) and were realized in aerobic condition. Operating on site, in the laundry, reactors were fed actual wastewater from the laundry retention tank. The laundry wastewater contained mainly surfactants and impurities originating from washed fabrics; a solution of urea to supplement nitrogen content and a solution of acid to correct pH were added. The daily flow of raw wastewater Qd varied from 0.6-1.0 m 3 /d. Wastewater quality indicators showed that the reduction of pollutants was obtained: BOD 5 by 95-98%, COD by 89-94%, the sum of anionic and nonionic surfactants by 85-96%. The quality of the purified wastewater after the start-up period met legal requirements regarding the standards for wastewater discharged into the environment. Copyright © 2018 Elsevier B.V. All rights reserved.

Highly-resolved numerical simulations of bed-load transport in a turbulent open-channel flow

NASA Astrophysics Data System (ADS)

Vowinckel, Bernhard; Kempe, Tobias; Nikora, Vladimir; Jain, Ramandeep; Fröhlich, Jochen

2015-11-01

The study presents the analysis of phase-resolving Direct Numerical Simulations of a horizontal turbulent open-channel flow laden with a large number of spherical particles. These particles have a mobility close to their threshold of incipient motion andare transported in bed-load mode. The coupling of the fluid phase with the particlesis realized by an Immersed Boundary Method. The Double-Averaging Methodology is applied for the first time convolutingthe data into a handy set of quantities averaged in time and space to describe the most prominent flow features.In addition, a systematic study elucidatesthe impact of mobility and sediment supply on the pattern formation of particle clusters ina very large computational domain. A detailed description of fluid quantities links the developed particle patterns to the enhancement of turbulence and to a modified hydraulic resistance. Conditional averaging isapplied toerosion events providingthe processes involved inincipient particle motion. Furthermore, the detection of moving particle clusters as well as their surrounding flow field is addressedby a a moving frameanalysis. Funded by German Research Foundation (DFG), project FR 1593/5-2, computational time provided by ZIH Dresden, Germany, and JSC Juelich, Germany.

Degradation of mecoprop in polluted landfill leachate and waste water in a moving bed biofilm reactor.

PubMed

Escolà Casas, Mònica; Nielsen, Tue Kjærgaard; Kot, Witold; Hansen, Lars Hestbjerg; Johansen, Anders; Bester, Kai

2017-09-15

Mecoprop is a common pollutant in effluent-, storm- and groundwater as well as in leachates from derelict dumpsites. Thus, bioremediation approaches may be considered. We conducted batch experiments with moving bed biofilm (MBBR)-carriers to understand the degradation of mecoprop. As a model, the carriers were incubated in effluent from a conventional wastewater treatment plant which was spiked to 10, 50 and 100 μg L -1 mecoprop. Co-metabolic processes as well as mineralization were studied. Initial mecoprop concentration and mecoprop degradation impacted the microbial communities. The removal of (S)-mecoprop prevailed over the (R)-mecoprop. This was associated with microbial compositions, in which several operational taxonomic units (OTUs) co-varied positively with (S)-mecoprop removal. The removal-rate constant of (S)-mecoprop was 0.5 d -1 in the 10 μg L -1 set-up but it decreased in the 50 and 100 μg L -1 set-ups. The addition of methanol prolonged the removal of (R)-mecoprop. During mecoprop degradation, 4-chloro-2-methylphenol was formed and degraded. A new metabolite (4-chloro-2-methylphenol sulfate) was identified and quantified. Copyright © 2017 Elsevier Ltd. All rights reserved.

Responses of biofilm characteristics to variations in temperature and NH4(+)-N loading in a moving-bed biofilm reactor treating micro-polluted raw water.

PubMed

Zhang, Shuangfu; Wang, Yayi; He, Weitao; Wu, Min; Xing, Meiyan; Yang, Jian; Gao, Naiyun; Yin, Daqiang

2013-03-01

A pilot-scale moving-bed biofilm reactor (MBBR) for biological treatment of micro-polluted raw water was operated over 400days to investigate the responses of biofilm characteristics and nitrification performance to variations in temperature and NH4(+)-N loading. The mean removal efficiency of NH4(+)-N in the MBBR reached 71.4±26.9%, and batch experiments were performed to study nitrification kinetics for better process understanding. Seven physical-chemical parameters, including volatile solids (VS), polysaccharides (PS) and phospholipids (PL) increased firstly, and then rapidly decreased with increasing temperature and NH4(+)-N loading, and properly characterized the attached biomass during biofilm development and detachment in the MBBR. The biofilm compositions were described by six ratios, e.g., PS/VS and PL/VS ratios showed different variation trends, indicating different responses of PS and PL to the changes in temperature and NH4(+)-N loading. Furthermore, fluorescent in situ hybridization (FISH) analysis revealed that increased NH4(+)-N loadings caused an enrichment of the nitrifying biofilm. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Factors for Degaussing of a Cochlear Implant Magnet in the MR Scanner].

PubMed

Koganezawa, Takumi; Uchiyama, Naoko; Teshigawara, Mai; Ogura, Akio

This study examined the conditions influencing degauss of the magnet using magnetic resonance imaging (MRI). Poly methyl methacrylate (PMMA) was used to fix the measurement magnets to the MRI bed at angles from 0° to 180° for the magnetic flux vector of static magnetic field. The PMMA was moved in the MRI magnetic field. Magnetic flux density was measured before and after bed movement, and the rate of degauss was calculated. The contents examined are as follows: (1) the angle of the magnetic flux vector of the measurement magnets for the magnetic flux vector of the static magnetic field, (2) the number of movements, (3) moving velocity, and (4) the movement on the spatial gradient of magnetic field. Mann-Whitney U test was used for statistical analysis of the data. In conclusion, the effect of the angle of the magnetic flux vector of the implant magnet was high under the conditions of degauss in this study. Therefore, during the MRI examination of a patient with a cochlear implant magnet, the operators identified the directions of the magnetic flux vector and static magnetic field of the implant magnet.

Impact of fine mesh sieve primary treatment on nitrogen removal in moving bed biofilm reactors.

PubMed

Rusten, B; Razafimanantsoa, V A; Andriamiarinjaka, M A; Otis, C L; Sahu, A K; Bilstad, T

2016-01-01

The purpose of this project was to investigate the effect of selective particle removal during primary treatment on nitrogen removal in moving bed biofilm reactors (MBBRs). Two small MBBR pilot plants were operated in parallel, where one train treated 2 mm screened municipal wastewater and the other train treated wastewater that had passed through a Salsnes Filter SF1000 rotating belt sieve (RBS) with a 33 µs sieve cloth. The SF1000 was operated without a filter mat on the belt. The tests confirmed that, for the wastewater characteristics at the test plant, Salsnes Filter primary treatment with a 33 µs RBS and no filter mat produced a primary effluent that was close to optimum. Removal of organic matter with the 33 µs sieve had no negative effect on the denitrification process. Nitrification rates improved by 10-15% in the train with 33 µs RBS primary treatment. Mass balance calculations showed that without RBS primary treatment, the oxygen demand in the biological system was 36% higher. Other studies have shown that the sludge produced by RBS primary treatment is beneficial for biogas production and will also significantly improve sludge dewatering of the combined primary and biological sludge.

Glacitectonic deformation around the retreating margin of the last Irish ice sheet

NASA Astrophysics Data System (ADS)

Knight, J.

2008-12-01

Evidence for ice-marginal glacitectonic shunting and deformation of bedrock slabs is described from three sites around the west coast of Ireland. These sites (Brandon Bay, County Kerry; Pigeon Point, County Mayo; Inishcrone, County Sligo) are all locations where the late Devensian ice margin retreated on land and was confined to within limestone bedrock embayments. At these sites, flat-lying bedrock slabs (< 8 m long) have been dissociated from rockhead and moved seaward (in the direction of ice flow) by glacitectonic shunting. At all of the sites, bedrock slabs have been variously stacked, rotated, deformed into open folds, and brecciated. Separating the bedrock slabs is either a thin layer (< 20 cm) of brecciated and mylonitised cemented bedrock that shows internal folding; or a thicker (< 50 cm) normally-graded diamicton with a fine matrix. Together, the presence of these features suggests oscillation of a polythermal and clean basal ice margin that was strongly associated with basal freeze-on and the presence of proglacial permafrost. Subglacial sediment-laden meltwater was focused from behind the ice margin and through permafrost taliks. It is suggested that hydrofracturing under high hydraulic pressure, and through a frozen-bed ice margin, forced sediment injection into bedrock fractures and bedding planes and away from the ice margin, and that bedrock slabs were moved in part by hydraulic lift as well as thrust-style ice-marginal tectonics. The presence of a mosaic of warm and frozen ice-bed patches, in combination with strong geologic control and meltwater generation from behind the ice margin, can help explain formation of these unusual bedrock slab features.

Optical coherence tomography for non-destructive analysis of coatings in pharmaceutical tablets

NASA Astrophysics Data System (ADS)

Markl, Daniel; Hannesschläger, Günther; Sacher, Stephan; Khinast, Johannes G.; Leitner, Michael

2013-04-01

Tablet coating is a common pharmaceutical technique to apply a thin continuous layer of solid on the top of a tablet or a granule containing active pharmaceutical ingredients (APIs). Coating thickness and homogeneity are critical parameters regarding the drug release rate, and consequently a direct or indirect monitoring strategy of these critical process parameters is essential. With the aid of Optical Coherence Tomography (OCT) it is not only possible to measure the absolute coating thickness, but also to detect inhomogeneities in the coating or substrate material. In this work the possible application of OCT as in-line method for monitoring pharmaceutical tablet film coating is studied. Firstly, the feasibility of OCT for analysis tablet coating is examined. Seven different commercially available film-coated tablets with different shapes, formulations and coating thicknesses were investigated off-line. OCT images were acquired by two different spectral-domain OCT systems operating at center wavelengths of 830 and 1325 nm. Since the images of both systems allow the analysis of the coatings, the OCT system employing the shorter wavelength and thus providing a higher axial resolution was selected for the further experiments. The influence of a moving tablet bed on OCT images was analyzed by considering a static tablet bed and moving the sensor head along the tablet bed. The ability to analyze the coating homogeneity is limited to a speed up to 0.3 m/s. However, determining the coating thickness and inter-coating uniformity is still possible up to a speed of 0.7 m/s.

Tetherless ergonomics workstation to assess nurses' physical workload in a clinical setting.

PubMed

Smith, Warren D; Nave, Michael E; Hreljac, Alan P

2011-01-01

Nurses are at risk of physical injury when moving immobile patients. This paper describes the development and testing of a tetherless ergonomics workstation that is suitable for studying nurses' physical workload in a clinical setting. The workstation uses wearable sensors to record multiple channels of body orientation and muscle activity and wirelessly transmits them to a base station laptop computer for display, storage, and analysis. In preparation for use in a clinical setting, the workstation was tested in a laboratory equipped for multi-camera video motion analysis. The testing included a pilot study of the effect of bed height on student nurses' physical workload while they repositioned a volunteer posing as a bedridden patient toward the head of the bed. Each nurse subject chose a preferred bed height, and data were recorded, in randomized order, with the bed at this height, at 0.1 m below this height, and at 0.1 m above this height. The testing showed that the body orientation recordings made by the wearable sensors agreed closely with those obtained from the video motion analysis system. The pilot study showed the following trends: As the bed height was raised, the nurses' trunk flexion at both thoracic and lumbar sites and lumbar muscle effort decreased, whereas trapezius and deltoid muscle effort increased. These trends will be evaluated by further studies of practicing nurses in the clinical setting.

Buffer management to solve bed-blocking in the Netherlands 2000–2010. Cooperation from an integrated care chain perspective as a key success factor for managing patient flows

PubMed Central

Mur-Veeman, Ingrid; Govers, Mark

2011-01-01

Introduction Bed-blocking problems in hospitals reflect how difficult and complex it is to move patients smoothly through the chain of care. In the Netherlands, during the first decade of the 21st century, some hospitals attempted to tackle this problem by using an Intermediate Care Department (ICD) as a buffer for bed-blockers. However, research has shown that ICDs do not sufficiently solve the bed-blocking problem and that bed-blocking is often caused by a lack of buffer management. Tool Buffer management (BM) is a tool that endeavors to balance patient flow in the hospital to nursing home chain of care. Results Additional research has indicated that the absence of BM is not the result of providers’ thinking that BM is unnecessary, unethical or impossible because of unpredictable patient flows. Instead, BM is hampered by a lack of cooperation between care providers. Conclusion Although stakeholders recognize that cooperation is imperative, they often fail to take the actions necessary to realize cooperation. Our assumption is that this lack of willingness and ability to cooperate is the result of several impeding conditions as well as stakeholders’ perceptions of these conditions and the persistence of their current routines, principles and beliefs (RPBs). Discussion We recommend simultaneously working on improving the conditions and changing stakeholders’ perceptions and RPBs. PMID:21954373

Rapid Cycle Amine (RCA 2.0) System Development

NASA Technical Reports Server (NTRS)

Papale, William; O'Coin, James; Wichowski, Robert; Chullen, Cinda; Campbell, Colin

2012-01-01

The Rapid Cycle Amine (RCA) system is a low power assembly capable of simultaneously removing carbon dioxide (CO2) and humidity from an influent air steam and subsequent regeneration when exposed to a vacuum source. Two solid amine sorbent beds are alternated between an uptake mode and a regeneration mode. During the uptake mode, the sorbent is exposed to an air steam (ventilation loop) to adsorb CO2 and water vapor, while during the regeneration mode, the sorbent rejects the adsorbed CO2 and water vapor to a vacuum source. The two beds operate such that while one bed is in the uptake mode, the other is in the regeneration mode, thus continuously providing an on-service sorbent bed by which CO2 and humidity may be removed. A novel valve assembly provides a simple means of diverting the process air flow through the uptake bed while simultaneously directing the vacuum source to the regeneration bed. Additionally, the valve assembly is designed to allow for switching between uptake and regeneration modes with only one moving part while minimizing gas volume losses to the vacuum source by means of an internal pressure equalization step during actuation. The process can be controlled by a compact, low power controller design with several modes of operation available to the user. Together with NASA, United Technologies Corporation Aerospace Systems has been developing RCA 2.0 based on performance and design feedback on several sorbent bed test articles and valve design concepts. A final design was selected in November 2011 and fabricated and assembled between March and August 2012, with delivery to NASA-JSC in September 2012. This paper will provide an overview on the RCA system design and results of pre-delivery testing.

Rapid Cycle Amine (RCA 2.0) System Development

NASA Technical Reports Server (NTRS)

Papale, William; O'Coin, James; Wichowski, Robert; Chullen, Cinda; Campbell, Colin

2013-01-01

The Rapid Cycle Amine (RCA) system is a low-power assembly capable of simultaneously removing carbon dioxide (CO2) and humidity from an influent air steam and subsequent regeneration when exposed to a vacuum source. Two solid amine sorbent beds are alternated between an uptake mode and a regeneration mode. During the uptake mode, the sorbent is exposed to an air steam (ventilation loop) to adsorb CO2 and water (H2O) vapor, whereas during the regeneration mode, the sorbent rejects the adsorbed CO2 and H2O vapor to a vacuum source. The two beds operate such that while one bed is in the uptake mode, the other is in the regeneration mode, thus continuously providing an on-service sorbent bed by which CO2 and humidity may be removed. A novel valve assembly provides a simple means of diverting the process air flow through the uptake bed while simultaneously directing the vacuum source to the regeneration bed. Additionally, the valve assembly is designed to allow for switching between uptake and regeneration modes with only one moving part while minimizing gas volume losses to the vacuum source by means of an internal pressure equalization step during actuation. The process can be controlled by a compact, low-power controller design with several modes of operation available to the user. Together with NASA Johnson Space Center, Hamilton Sundstrand Space Systems International, Inc. has been developing RCA 2.0 based on performance and design feedback on several sorbent bed test articles and valve design concepts. A final design of RCA 2.0 was selected in November 2011 and fabricated and assembled between March and August 2012, with delivery to NASA Johnson Space Center in September 2012. This paper provides an overview of the RCA system design and results of pre-delivery testing.

Cyclic Steps and Antidunes : Relating Their Features to a Suspension Index

NASA Astrophysics Data System (ADS)

Yokokawa, M.; Kishima, Y.; Parker, G.

2010-12-01

Cyclic Steps and Antidunes : Relating Their Features to a Suspension Index Miwa Yokokawa (1), Yasushi Kishima (1), Gary Parker (2, 3) 1: Osaka Institute of Technology, Hirakata, Osaka, Japan 2: Dept. of Civil & Environmental Engineering, University of Illinois, Urbana, Illinois, U.S.A. 3: Dept. of Geology, University of Illinois, Urbana, Illinois, U.S.A. There are very few comparative studies of the differences in hydraulic conditions and morphologic features of bed- and water-surface-waves associated with cyclic steps and antidunes. In this study, the features of both the bed and the water surface, as well as hydraulic conditions are examined over the spectrum from antidune to cyclic steps. Experiments were performed using a flume at the Osaka Institute of Technology. The resultant features of the bedforms are as follows. In the case of antidunes, bed waves and water surface waves are in phase except when they collapse. Antidunes show several kinds of behavior; migrating downstream, standing, or migrating upstream. Upstream-migrating antidunes are divided into non-breaking, and breaking-types. Breaking antidunes appear alternatively with the plane bed state. Cyclic steps migrate upstream regularly associated with trains of hydraulic jumps, which divide each step. There is a significant change in water depth at the hydraulic jump, so that the phasing between the bed waves and water surface waves break at the each hydraulic jump. There is a kind of compromise between cyclic steps and antidunes, which we designate as “intermediate steps”. They move upstream and are associated with regular trains of hydraulic jumps. The jumps, however, occasionally collapse toward upstream. When this happens, bed waves move rapidly upstream; low-amplitude water surface waves and bed waves become in phase all over the bed shortly after the collapse. Then after some time, water surface waves become sufficiently prominent to yield regular hydraulic jumps. This cycle is then repeated.The hydraulic conditions for these bedfoms were examined using three non-dimensional parameters, i.e. the Froude Number, the Suspension Index, and the dimensionless particle size. The suspension index is a newly introduced parameter which is the ratio of the shear velocity divided by the settling velocity of the sediment (u*/Vs). Data from previous experimental studies are examined together with the present data in studying the characteristic regimes of bedform formation. In a diagram of Froude Number v.s. Suspension Index, antidunes, intermediate steps and cyclic steps can be divided along the axis of the Suspension Index. In the lowest range of the suspension index, downstream-migrating antidunes and upstream-migrating antidunes that do not break are found. The intermediate steps discussed above are located in the middle range. The highest range corresponds to cyclic steps and breaking antidunes. As described above, the Suspension Index can serve as a scale to quantify the spectrum between antidunes and cyclic steps. The use of the parameter also helps verify that suspension plays an important role in the formation and maintenance of cyclic steps.

Numerical simulation of turbulence and sediment transport of medium sand

NASA Astrophysics Data System (ADS)

Schmeeckle, M. W.

2012-12-01

Eleven numerical simulations, ranging from no transport to bedload to vigorous suspension transport, are presented of a combined large eddy simulation (LES) and distinct element model (DEM) of an initially flat bed of medium sand. The fluid and particles are fully coupled in momentum. The friction coefficient, defined here as the squared ratio of the friction velocity to the depth-averaged velocity, is in good agreement with well-known rough bed relations at no transport and increases with the intensity of bedload transport. The friction coefficient nearly doubles in value at the onset of sediment suspension owing to a rapid increase of the depth over which particles and fluid exchange momentum. The friction coefficient decreases with increasing suspension intensity because of increasingly stable stratification. Fluid Reynolds stress and time-averaged velocity profiles in the bedload regime agree well with previous experiments and simulations. Also consistent with previous studies of suspended sediment, there is an increase in slope of the lower portion of the velocity profile that has been modeled in the past using stably stratified eddy viscosity closures or an adjusted von Karman constant. Stokes numbers in the simulations, using an estimated lagrangian integral time scale, are less than unity. As such, particles faithfully follow the fluid, except for particle settling and grain-grain interactions near the bed. Fluid-particle velocity correlation coefficients approach one in portions of the flow where volumetric sediment concentrations are below about ten percent. Bedload entrainment is critically connected to vertical velocity fluctuations. When a fluid packet approaches the bed from the interior of the flow (i.e. a sweep), fluid is forced into the bed, and at the edges of the sweep, fluid is forced out of the bed. Much of the particle entrainment occurs at these sweep edges. Fluid velocity statistics following the particles reveal that moving bedload particles are preferentially concentrated in zones of upward fluid velocity. This may explain previous observations noting a rapid vertical rise at the beginning of saltation trajectories. The simulations described here have no lift forces. Because of the short particle time scales relative to that of the turbulent structures, high transport stage bedload entrainment zones involve mutual interaction between turbulence structures and bed deformation. These deformation structures appear as depressed areas of the bed at the center of the sweep and raised areas of entraining particles at the edges of the sweep penetration. Suspended sediment entrainment structures are similar to these bedload entrainment structures but have much larger scales. Preferential concentration of suspended grains in zones of upward moving fluid dampens turbulence intensities and momentum transport. Much of the suspended transport takes place within this highly concentrated near-bed zone of damped turbulence. Particle-fluid correlation coefficients are relatively low in the lower portion of this highly concentrated suspended sediment zone, owing to particle-particle interactions. As such, Rouse-like profiles utilizing eddy viscosity closures, adjusted according to flux Richardson numbers, do not adequately describe the physics of this zone.

Continuous countercurrent membrane column for the separation of solute/solvent and solvent/solvent systems

DOEpatents

Nerad, Bruce A.; Krantz, William B.

1988-01-01

A reverse osmosis membrane process or hybrid membrane - complementary separator process for producing enriched product or waste streams from concentrated and dilute feed streams for both solvent/solvent and solute/solvent systems is described.

Experimental Bedrock Channel Incision: Scaling, Sculpture and Sediment Transport

NASA Astrophysics Data System (ADS)

Johnson, J. P.; Whipple, K. X.

2004-12-01

Abrasion by sediment in turbulent flows often sculpts bedrock channels into dramatic forms; quantifying the feedbacks between fluid flow, sediment impacts, and channel morphology is needed to refine models of fluvial incision into bedrock. We present data from laboratory flume experiments funded by the National Center for Earth-Surface Dynamics and conducted at St. Anthony Falls Laboratory, University of Minnesota that show how the spatial and temporal distribution of erosion is strongly coupled to the evolving topography of the bed. These experiments focus on the high Froude number and tool-starved end of parameter space, where bed cover tends to be negligible. Independent variables include flume slope, water flux and sediment flux and size distribution. Sediment moves energetically as bedload, suspended load, or locally transitional between transport modes. Quantitative measurements of the evolving bed topography show that the synthetic brittle "bedrock" in the flume (cured sand-cement mixture) eroded to form narrow incised channels with tight scoops and potholes. The experimental erosional forms are similar in morphology, and sometimes in scale, to those observed in natural bedrock rivers in southeast Utah and other field settings. The experiments demonstrate that both the mean and distribution of measured erosion rates change as the bed topography evolves, even with constant water and sediment discharges. Even starting with a plane bed geometry, erosion and sediment transport very quickly become localized in interconnected topographic lows. Positive feedback develops between the evolving topography and the fluid velocity and sediment transport fields, resulting in the incision of an inner channel. Once formed, the erosion rate in the axis of the inner channel decreases as local bed shear stresses and fluid velocities are reduced by increasing wall drag, and sediment fluxes through the channel but causes less incision (no deposition). Decreasing the sediment flux (all else held equal) causes renewed incision, but of an even narrower inner channel; increasing the sediment flux leads to inner channel deposition. Where erosion is most vigorous, sediment generally moving as saltating bedload becomes locally suspended by upward-directed mean flow. For example, swirling clouds of "bedload" particles are continuously suspended by vortices developed within potholes such that the upward flux of particles out of the potholes balance the total sediment flux through the flume. Potholes spontaneously form where average bed slope and fluid velocities were highest, dramatically accelerating the local erosion rate. Our experimental potholes are smaller in scale but morphologically strikingly similar to many observed in the field, and include features such as corkscrew grooves down the outside walls and a protruding horn at the pothole center. More generally, abrasion becomes focused in places where the flow is spatially accelerated, such as in scoops and bends with high curvature. The knife-edge margins and spatial distribution of erosional forms indicate abrupt transitions in erosional efficiency that are tightly coupled to near-bed fluid flow patterns, which in turn are strongly influenced by the erosional forms themselves. Our experiments suggest that, in highly sculpted bedrock channels, naturally developed bed roughness presents a physical length scale that is important to controlling the interaction between sediment impacts and the bed, rather than a length scale based explicitly on sediment transport and average flow conditions such as the saltation hop length.

Bedload and river hydraulics - Inferences from the East Fork River, Wyoming

USGS Publications Warehouse

Leopold, Luna Bergere; Emmett, William W.

1997-01-01

During 1973-79, bedload data were collected in a sophisticated trap on a river of moderate size, the East Fork. The transport rate was measured most days through a full snowmelt season, and the rate was determined separately for eight zones across the channel width. The quantitative data are unique and unlikely to be repeated. Nor need they be, because as a result of this effort a practical bedload sampler was adequately tested against full river measurement.It was shown that bedload moves sporadically and randomly on the river bed. Therefore, transport rate is highly variable in short periods of time. There is also a wide variance from day to day. Yet, different rivers have transport rates, which are functions of discharge, depth, and sediment size, that are clearly distinct. Comparison of computed and measured transport rates indicates that a major problem remains: What grain size is representative of the bedload when there is a wide or heterogeneous particle-size distribution? Size of the bedload in motion may be very different from the size of bed material obtained from samples of the streambed.For general computation, the river channel slope may be averaged, and it may be assumed that water-surface slope does not change materially with changing discharge. Indeed, this generality is correct, in that, compared with depth, velocity, and width, slope is conservative at-a-station. However, in more detail, slope changes importantly with discharge in short reaches of channel, and those changes are very different in pool and riffle.These local changes in slope are not merely an aspect of a detailed longitudinal profile but involve cross-channel as well as down-channel components. The pool and riffle sequence involves not only undulation of bed elevation and bar formation on alternate sides of the channel, but alternation of the zone of superovulation of the water surface, and changing relation of watersurface slope to discharge. These details can be seen only in the full topography of the water surface. Riffles fill during high flow and scour at low flow. Changes in local water-surface slope illustrate this process. Pools are a storage zone for sediment in the low-flow season. Even though large volumes of sediment move, the distance moved is not large—in the East Fork River, sand of size 0.5-1 millimeter moved 650 meters during the 1979 snowmelt runoff season.Bedload transport is greatest over or near bars and not in the deepest part of the channel. Direct observation of the locus of sediment transport indicates that this locus moves from one side of the channel to the other in concert with the occurrence of alternate bars. Separately, data indicate that at constant stream power, transport rate increases as depth decreases.

The impact of benthic fauna on fluvial bed load transport: Challenges of upscaling laboratory experiments to river and landscape scales.

NASA Astrophysics Data System (ADS)

Rice, S. P.

2012-04-01

The impact on sediment transport processes and channel morphology of several relatively large, iconic animals including beaver and salmon is increasingly well understood. However, many other aquatic fauna are important zoogeomorphic agents and ecosystem engineers. These somewhat overlooked "Cinderella" species include benthic aquatic insect larvae, freshwater crustaceans and many species of fish. Despite relatively modest individual effects, the ubiquity, abundance and cumulative impact of these organisms makes them a potentially significant agency, with as yet undiscovered and unquantified impacts on channel morphology and sediment fluxes. Their actions (digging, foraging, moving, burrowing), constructions and secretions modify bed sediment characteristics (grain size distribution, interlock, imbrication, protrusion), alter bed topography (thence hydraulic roughness) and contribute to biogenic restraints on grain movement. In turn, they can affect the distribution of surface particle entrainment thresholds and bed shear stresses, with implications for bed load transport. Flume experiments have measured some of these impacts and provided direct observations of the mechanisms involved, but many of the most interesting research questions pertain to the impact of these animals at reach, catchment and even landscape scales: Not least, what is the impact of small aquatic animals on bed load flux and yield? This presentation will consider some of the challenges involved in answering this question; that is, of scaling up experimental understanding of how aquatic animals affect bed load transport processes to river scales. Pertinent themes include: (1) the potential impacts of experimental arrangements on the behaviours and activities that affect hydraulic or geomorphological processes; (2) field coincidence of the spatial and temporal distributions of (a) the animals and their behaviours with (b) the physical conditions (substrates, flows) under which those animals are understood to have an effect; (3) the magnitude of any demonstrable net field impact, relative to those other factors that control bed load transport rates.

Moving Target Techniques: Leveraging Uncertainty for CyberDefense

DTIC Science & Technology

2015-12-15

cyberattacks is a continual struggle for system managers. Attackers often need only find one vulnerability (a flaw or bug that an attacker can exploit...additional parsing code itself could have security-relevant software bugs . Dynamic  Network   Techniques in the dynamic network domain change the...evaluation of MT techniques can benefit from a variety of evaluation approaches, including abstract analysis, modeling and simulation, test bed

Effects of alkalinity on ammonia removal, carbon dioxide stripping, and system pH in semi-commercial scale water recirculating aquaculture systems operated with moving bed bioreactors

USDA-ARS?s Scientific Manuscript database

When operating water recirculating systems (RAS) with high make-up water flushing rates in locations that have low alkalinity in the raw water, such as Norway, knowledge about the required RAS alkalinity concentration is important. Flushing RAS with make-up water containing low alkalinity washes out...

Move to outpatient settings may boost medical hotels.

PubMed

Burns, J

1992-06-08

The shift of surgeries to outpatient settings could be healthy for medical hotels, those amenity-equipped facilities originally developed to ease patients out of costly acute-care beds. Because fewer hospitals have a pressing need to use such alternative lodging, some medical hotels are hoping to hitch their fortunes to the outpatient trade, keeping patients overnight after surgeries that don't require hospital admission.

Development of Additional Hazard Assessment Models

DTIC Science & Technology

1977-03-01

globules, their trajectory (the distance from the spill point to the impact point on the river bed), and the time required for sinking. Established theories ...chemicals, the dissolution rate is estimated by using eddy diffusivity surface renewal theories . The validity of predictions of these theories has been... theories and experimental data on aeration of rivers. * Describe dispersion in rivers with stationary area source and sources moving with the stream

Missouri gravel bed and a pot-in-pot system superior to white polyethylene and foam for overwintering Syringa pubescens subsp patula Liners

Treesearch

Steven D. Kirk; Chris J. Starbuck; J.W. Van Sambeek

2004-01-01

The production of containerized nursery stock started in southern California because of its mild climate and long growing season (Whitcomb, 1987). As production of containerized stock moved into areas of the country with harsher climates, methods of overwintering were developed to protect plants from winter damage. Proper winter protection in the production of...

Multi-objective optimization for the economic production of d-psicose using simulated moving bed chromatography.

PubMed

Wagner, N; Håkansson, E; Wahler, S; Panke, S; Bechtold, M

2015-06-12

The biocatalytic production of rare carbohydrates from available sugar sources rapidly gains interest as a route to acquire industrial amounts of rare sugars for food and fine chemical applications. Here we present a multi-objective optimization procedure for a simulated moving bed (SMB) process for the production of the rare sugar d-psicose from enzymatically produced mixtures with its epimer d-fructose. First, model parameters were determined using the inverse method and experimentally validated on a 2-2-2-2 lab-scale SMB plant. The obtained experimental purities (PUs) were in excellent agreement with the simulated data derived from a transport-dispersive true-moving bed model demonstrating the feasibility of the proposed design. In the second part the performance of the separation was investigated in a multi-objective optimization study addressing the cost-contributing performance parameters productivity (PR) and desorbent requirement (DR) as a function of temperature. While rare sugar SMB operation under conditions of low desorbent consumption was found to be widely unaffected by temperature, SMB operation focusing on increased PR significantly benefited from high temperatures, with possible productivities increasing from 3.4kg(Lday)(-1) at 20°C to 5kg(Lday)(-1) at 70°C, indicating that decreased selectivity at higher temperatures could be fully compensated for by the higher mass transfer rates, as they translate into reduced switch times and hence higher PR. A DR/PR Pareto optimization suggested a similar but even more pronounced trend also under relaxed PU requirements, with the PR increasing from 4.3kg(Lday)(-1) to a maximum of 7.8kg(Lday)(-1) for SMB operation at 50°C when the PU of the non-product stream was reduced from 99.5% to 90%. Based on the in silico optimization results experimental SMB runs were performed yielding considerable PRs of 1.9 (30°C), 2.4 (50°C) and 2.6kg(Lday)(-1) (70°C) with rather low DR (27L per kg of rare sugar produced) on a lab-scale SMB installation. Copyright © 2015. Published by Elsevier B.V.

Improved separation with the intermittently pressed tubing of multilayer coil in type-I counter-current chromatography.

PubMed

Yang, Yi; Yang, Jiao; Fang, Chen; Wang, Jihui; Gu, Dongyu; Tian, Jing; Ito, Yoichiro

2018-05-25

The intermittently pressed tubing was introduced in type-I counter-current chromatographic system as the separation column to improve the separation performance in the present study. The separations were performed with two different solvent systems composed of 1-butanol-acetic acid-water (4:1:5, v/v) (BAW) and hexane-ethyl acetate-methanol-0.1 M HCl (1:1:1:1, v/v) (HEMW) using dipeptides and DNP-amino acids as test samples, respectively. The chromatographic performance was evaluated in terms of retention of the stationary phase (Sf), theoretical plate (N) and peak resolution (Rs). In general, the type-I planetary motion with the multilayer coil of non-modified standard tubing can yield the best separation at a low revolution speed of 200 rpm with lower flow rate. The present results with intermittently pressed tubing indicated that the performance was also optimal at the revolution speed of 200 rpm where the lower flow rate was more beneficial to retention of stationary phase and resolution. In the moderately hydrophobic two-phase solvent system composed of hexane-ethyl acetate-metanol-0.1 M hydrochloric acid (1:1:1:1, v/v), DNP-amino acids were separated with Rs at 1.67 and 1.47, respectively, with 12.66% of stationary phase retention at a flow rate of 0.25 ml/min. In the polar solvent system composed of 1-butanol-acetic acid-water (4:1:5, v/v), dipeptide samples were resolved with Rs at 2.18 and 18.75% of stationary phase retention at a flow rate of 0.25 ml/min. These results indicate that the present system substantially improves the separation efficiency of type-I counter-current chromatographic system. Published by Elsevier B.V.

Partition efficiencies of newly fabricated universal high-speed counter-current chromatograph for separation of two different types of sugar derivatives with organic-aqueous two-phase solvent systems.

PubMed

Shinomiya, Kazufusa; Sato, Kazuki; Yoshida, Kazunori; Tokura, Koji; Maruyama, Hiroshi; Yanagidaira, Kazuhiro; Ito, Yoichiro

2013-12-27

A new design of universal high-speed counter-current chromatograph (HSCCC) was fabricated in our laboratory. It holds a set of four column holders symmetrically around the rotary frame at a distance of 11.2cm from the central axis. By engaging the stationary gear on the central axis of the centrifuge to the planetary gears on the column holder shaft through a set of idle gears, two pairs of diagonally located column holders simultaneously rotate about their own axes in the opposite directions: one forward (type-J planetary motion) and the other backward (type-I planetary motion) each synchronously with the revolution. Using the eccentric coil assembly, partition efficiencies produced by these two planetary motions were compared on the separation of two different types of sugar derivatives (4-methylumbelliferyl and 5-bromo-4-chloro-3-indoxyl sugar derivatives) using organic-aqueous two-phase solvent systems composed of n-hexane/ethyl acetate/1-butanol/methanol/water and aqueous 0.1M sodium tetraborate, respectively. With lower phase mobile, better peak resolution was obtained by the type-J forward rotation for both samples probably due to higher retention of the stationary phase. With upper phase mobile, however, similar peak resolutions were obtained between these two planetary motions for both sugar derivatives. The overall results indicate that the present universal HSCCC is useful for counter-current chromatographic separation since each planetary motion has its specific applications: e.g., vortex CCC by the type-I planetary motion and HSCCC by the type-J planetary motion both for separation of various natural and synthetic products. Copyright © 2013 Elsevier B.V. All rights reserved.

Multiple dual mode counter-current chromatography with variable duration of alternating phase elution steps.

PubMed

Kostanyan, Artak E; Erastov, Andrey A; Shishilov, Oleg N

2014-06-20

The multiple dual mode (MDM) counter-current chromatography separation processes consist of a succession of two isocratic counter-current steps and are characterized by the shuttle (forward and back) transport of the sample in chromatographic columns. In this paper, the improved MDM method based on variable duration of alternating phase elution steps has been developed and validated. The MDM separation processes with variable duration of phase elution steps are analyzed. Basing on the cell model, analytical solutions are developed for impulse and non-impulse sample loading at the beginning of the column. Using the analytical solutions, a calculation program is presented to facilitate the simulation of MDM with variable duration of phase elution steps, which can be used to select optimal process conditions for the separation of a given feed mixture. Two options of the MDM separation are analyzed: 1 - with one-step solute elution: the separation is conducted so, that the sample is transferred forward and back with upper and lower phases inside the column until the desired separation of the components is reached, and then each individual component elutes entirely within one step; 2 - with multi-step solute elution, when the fractions of individual components are collected in over several steps. It is demonstrated that proper selection of the duration of individual cycles (phase flow times) can greatly increase the separation efficiency of CCC columns. Experiments were carried out using model mixtures of compounds from the GUESSmix with solvent systems hexane/ethyl acetate/methanol/water. The experimental results are compared to the predictions of the theory. A good agreement between theory and experiment has been demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

Experimental attrition rates of bed-material sediment from geologic provinces of Western Oregon and their application to regional sediment models

NASA Astrophysics Data System (ADS)

Mangano, J.; O'Connor, J. E.; Jones, K. L.; Wallick, R.

2011-12-01

Many topographic, hydrologic, and land use variables affect the supply and transport of bed-material in rivers, but the underlying geology is a key factor controlling both the volume of introduced material and the attrition of bed-material as it moves downstream. Recent and ongoing USGS river studies in Western Oregon document strong links between geologic province and bed-material transport. Rivers originating in the Mesozoic metamorphic and intrusive igneous rocks of the Klamath terranes of southwestern Oregon have the greatest gravel transport rates (and channel and valley-bottom morphologies reflecting high bed-material fluxes), whereas the generally lesser amounts of gravel in streams that drain Oregon's Coast Range and western Cascade Range owes in large part to Tertiary sedimentary and volcanic units underlying most of these basins. Aspects of these differences are controlled by supply as well as clast attrition. Here we aim to quantify bed-material attrition rates associated with the five main geologic provinces of Western Oregon: the Klamath terranes, Western Cascades, High Cascades, Coast Range sedimentary rocks, and Coast Range volcanic rocks. Bed-material samples were collected throughout the region from streams that drain a single geologic province and tumbled with a lapidary tumbler to determine relative attrition rates. Two kilograms of each sample were sorted into an initial distribution of clast sizes (from 16 to 64mm) and tumbled, with periodic breaks to reweigh and sieve the sample. Results show marked differences in attrition rates, with the sedimentary rocks of the Coast Range having weight loss coefficients between 1.206 and 0.211/km, orders of magnitude greater than all of the other sampled provinces. For comparison, bed material from the Klamath terranes have weight loss coefficients ranging from 0.013 to 0.005/km, and a control sample of quartzite clasts (from the Klamath terranes) has a weight loss coefficient of 0.001/km. These results confirm that bed-material attrition is an important process affecting bed-material supply and transport, and will allow for more complete development of regional bed-material sediment budgets in ongoing efforts to understand patterns of gravel abundance and channel morphology in rivers of Western Oregon.

Method of extracting iodine from liquid mixtures of iodine, water and hydrogen iodide

DOEpatents

Mysels, Karol J.

1979-01-01

The components of a liquid mixture consisting essentially of HI, water and at least about 50 w/o iodine are separated in a countercurrent extraction zone by treating with phosphoric acid containing at least about 90 w/o H.sub.3 PO.sub.4. The bottom stream from the extraction zone is substantially completely molten iodine, and the overhead stream contains water, HI, H.sub.3 PO.sub.4 and a small fraction of the amount of original iodine. When the water and HI are present in near-azeotropic proportions, there is particular advantage in feeding the overhead stream to an extractive distillation zone wherein it is treated with additional concentrated phosphoric acid to create an anhydrous HI vapor stream and bottoms which contain at least about 85 w/o H.sub.3 PO.sub.4. Concentration of these bottoms provides phosphoric acid infeed for both the countercurrent extraction zone and for the extractive distillation zone.

Isolation and Purification of Three Ecdysteroids from the Stems of Diploclisia glaucescens by High-Speed Countercurrent Chromatography and Their Anti-Inflammatory Activities In Vitro.

PubMed

Fang, Lei; Li, Jialian; Zhou, Jie; Wang, Xiao; Guo, Lanping

2017-08-07

High-speed counter-current chromatography was used to separate and purify ecdysteroids for the first time from the stems of Diploclisia glaucescens using a two-phase solvent system composed of ethyl acetate- n -butanol-ethanol-water (3:0.2:0.8:3, v / v ). Three ecdysteroids were obtained from 260 mg of ethyl acetate extract of the residue obtained after evaporation of the crude ethanolicextractof D. glaucescens in one-step separation, which were identified as paristerone ( I , 30.5 mg), ecdysterone ( II , 7.2 mg), and capitasterone ( III , 8.1 mg) by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR). Their anti-inflammatory activities were evaluated by measuring the inhibitory ratios of β-glucuronidase release in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor. Compounds I - III showed significant anti-inflammatory activities with IC 50 -values ranging from 1.51 to 11.68 μM, respectively.

Preparative isolation and purification of macrolactin antibiotics from marine bacterium Bacillus amyloliquefaciens using high-speed counter-current chromatography in stepwise elution mode.

PubMed

He, Shan; Wang, Hongqiang; Yan, Xiaojun; Zhu, Peng; Chen, Juanjuan; Yang, Rui

2013-01-11

Preparative high-speed counter-current chromatography (HSCCC) was successfully applied to the isolation and purification of two macrolactin antibiotics from marine bacterium Bacillus amyloliquefaciens for the first time using stepwise elution with a pair of two-phase solvent systems composed of n-hexane-ethyl acetate-methanol-water at (1:4:1:4, v/v) and (3:4:3:4, v/v). The preparative HSCCC separation was performed on 300 mg of crude sample yielding macrolactin B (22.7 mg) and macrolactin A (40.4 mg) in a one-step separation, with purities over 95% as determined by HPLC. The structures of these compounds were identified by MS, (1)H NMR and (13)C NMR. Our results demonstrated that HSCCC was an efficient technique to separate marine antibiotics, which provide an approach to solve the problem of their sample availability for drug development. Copyright © 2012 Elsevier B.V. All rights reserved.

Characterization of pigments from different high speed countercurrent chromatography wine fractions.

PubMed

Salas, Erika; Dueñas, Montserrat; Schwarz, Michael; Winterhalter, Peter; Cheynier, Véronique; Fulcrand, Hélène

2005-06-01

A red wine, made from Cabernet Sauvignon (60%) and Tannat (40%) cultivars, was fractionated by high speed countercurrent chromatography (HSCCC). The biphasic solvent system consisting of tert-butyl methyl ether/n-butanol/acetonitrile/water (2/2/1/5, acidified with 0.1% trifluoroacetic acid) was chosen for its demonstrated efficiency in separating anthocyanins. The different native and derived anthocyanins were identified on the basis of their UV-visible spectra, their elution time on reversed-phase high-performance liquid chromatography (HPLC), and their mass spectra, before and after thiolysis. The HSCCC method allowed the separation of different families of anthocyanin-derived pigments that were eluted in different fractions according to their structures. The hydrosoluble fraction was almost devoid of native anthocyanins. Further characterization (glucose quantification, UV-visible absorbance measurements) indicated that it contained flavanol and anthocyanin copolymers in which parts of the anthocyanin units were in colorless forms. Pigments in the hydrosoluble fraction showed increased resistance to sulfite bleaching and to the nucleophilic attack of water.

Novel linear and step-gradient counter-current chromatography for bio-guided isolation and purification of cytotoxic podophyllotoxins from Dysosma versipellis (Hance).

PubMed

Yang, Zhi; Liu, Xiaoman; Wang, Kuiwu; Cao, Xiaoji; Wu, Shihua

2013-03-01

Dysosma versipellis (Hance) is a famous traditional Chinese medicine for the treatment of snakebite, weakness, condyloma accuminata, lymphadenopathy, and tumors for thousands of years. In this work, four podophyllotoxin-like lignans including 4'-demethylpodophyllotoxin (1), α-peltatin (2), podophyllotoxin (3), β-peltatin (4) as major cytotoxic principles of D. versipellis were successfully isolated and purified by several novel linear and step gradient counter-current chromatography methods using the systems of hexane/ethyl acetate/methanol/water (4:6:3:7 and 4:6:4:6, v/v/v/v). Compared with isocratic elution, linear and step-gradient elution can provide better resolution and save more time for the separation of photophyllotoxin and its congeners. Their cytotoxicities were further evaluated and their structures were validated by high-resolution electrospray TOF MS and nuclear magnetic resonance spectra. All components showed potent anticancer activity against human hepatoma cells HepG2. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrahigh pressure extraction of lignan compounds from Dysosma versipellis and purification by high-speed counter-current chromatography.

PubMed

Zhu, Qing; Liu, Feng; Xu, Meixia; Lin, Xiaojing; Wang, Xiao

2012-09-15

Ultrahigh pressure extraction (UPE) was employed to extract podophyllotoxin and 4'-demethylpodophyllotoxin from Dysosma versipellis. The effects of extraction parameters including extraction solvents, pressure, time and solid/liquid ratio were investigated using a High Hydrostatic Pressure Processor. The optimal condition for UPE of the target compounds was 80% methanol, 200 MPa of pressure, 1 min of extraction time and 1:12 (g/mL) of solid/liquid ratio. Podophyllotoxin and 4'-demethylpodophyllotoxin in the crude extract were purified by high-speed counter-current chromatography (HSCCC) with a two-phase solvent system composed of petroleum ether-ethyl acetate-methanol-water (10:10:8:12, v/v), and the fractions were analyzed by HPLC, ESI-MS and (1)H NMR. As a result, 73.7 mg podophyllotoxin and 16.5mg 4'-demethylpodophyllotoxin with purities over 96% were obtained from 260 mg crude sample in one-step separation. Copyright © 2012 Elsevier B.V. All rights reserved.

Effect of Coriolis force on counter-current chromatographic separation by centrifugal partition chromatography.

PubMed

Ikehata, Jun-Ichi; Shinomiya, Kazufusa; Kobayashi, Koji; Ohshima, Hisashi; Kitanaka, Susumu; Ito, Yoichiro

2004-02-06

The effect of Coriolis force on the counter-current chromatographic separation was studied using centrifugal partition chromatography (CPC) with four different two-phase solvent systems including n-hexane-acetonitrile (ACN); tert-butyl methyl ether (MtBE)-aqueous 0.1% trifluoroacetic acid (TFA) (1:1); MtBE-ACN-aqueous 0.1% TFA (2:2:3); and 12.5% (w/w) polyethylene glycol (PEG) 1000-12.5% (w/w) dibasic potassium phosphate. Each separation was performed by eluting either the upper phase in the ascending mode or the lower phase in the descending mode, each in clockwise (CW) and counterclockwise column rotation. Better partition efficiencies were attained by the CW rotation in both mobile phases in all the two-phase solvent systems examined. The mathematical analysis also revealed the Coriolis force works favorably under the CW column rotation for both mobile phases. The overall results demonstrated that the Coriolis force produces substantial effects on CPC separation in both organic-aqueous and aqueous-aqueous two-phase systems.

Separation and purification of triterpene saponins from roots of Radix phytolaccae by high-speed countercurrent chromatography coupled with evaporative light scattering detection

PubMed Central

Ma, Jie; Chen, Qianliang; Lai, Daowan; Sun, Wenji; Zhang, Tianyou; Ito, Yoichiro

2009-01-01

Coupled with evaporative light scattering detection, high-speed countercurrent chromatography was successfully applied for the first time to separation and purification of four triterpene saponins including esculentoside A, B, C and D from roots of Radix Phytolaccae. The separation was performed with an optimized two-phase solvent system composed of chloroform-methanol-water (4:4:2, v/v) using the lower phase as the mobile phase at a flow rate of 1.5 ml/min,. From 150 mg of crude extract 46.3 mg of esculentoside A, 21.8 mg of esculentoside B, 7.3 mg of esculentoside C, and 13.6 mg of esculentoside D were obtained at purities of 96.7%, 99.2%, 96.5% and 97.8%, respectively, as determined by HPLC analysis. The structures of the four triterpene saponins were identified by ESI-MS,1H NMR and 13C NMR. PMID:20454595

Gas-liquid countercurrent integration process for continuous biodiesel production using a microporous solid base KF/CaO as catalyst.

PubMed

Hu, Shengyang; Wen, Libai; Wang, Yun; Zheng, Xinsheng; Han, Heyou

2012-11-01

A continuous-flow integration process was developed for biodiesel production using rapeseed oil as feedstock, based on the countercurrent contact reaction between gas and liquid, separation of glycerol on-line and cyclic utilization of methanol. Orthogonal experimental design and response surface methodology were adopted to optimize technological parameters. A second-order polynomial model for the biodiesel yield was established and validated experimentally. The high determination coefficient (R(2)=98.98%) and the low probability value (Pr<0.0001) proved that the model matched the experimental data, and had a high predictive ability. The optimal technological parameters were: 81.5°C reaction temperature, 51.7cm fill height of catalyst KF/CaO and 105.98kPa system pressure. Under these conditions, the average yield of triplicate experiments was 93.7%, indicating the continuous-flow process has good potential in the manufacture of biodiesel. Copyright © 2012 Elsevier Ltd. All rights reserved.

Colonization of the Hawaiian Archipelago via Johnston Atoll: a characterization of oceanographic transport corridors for pelagic larvae using computer simulation

NASA Astrophysics Data System (ADS)

Kobayashi, Donald R.

2006-08-01

Larval transport between Johnston Atoll and the Hawaiian Archipelago was examined using computer simulation and high-resolution ocean current data. The effects of pelagic larval duration and spawning seasonality on long-distance transport and local retention were examined using a Lagrangian, individual-based approach. Retention around Johnston Atoll appeared to be low, and there appeared to be seasonal effects on both retention and dispersal. Potential larval transport corridors between Johnston Atoll and the Hawaiian Archipelago were charted. One corridor connects Johnston Atoll with the middle portion of the Hawaiian Archipelago in the vicinity of French Frigate Shoals. Another corridor connects Johnston Atoll with the lower inhabited islands in the vicinity of Kauai. Transport appears to be related to the subtropical countercurrent and the Hawaiian Lee countercurrent, both located to the west of the archipelago and flowing to the east. A new analytical tool, termed CONREC-IRC is presented for the quantification of spatial patterns.

Preparative isolation and purification of theaflavins and catechins by high-speed countercurrent chromatography.

PubMed

Wang, Kunbo; Liu, Zhonghua; Huang, Jian-an; Dong, Xinrong; Song, Lubing; Pan, Yu; liu, Fang

2008-05-15

High-speed countercurrent chromatography (HSCCC) has been applied for the separation of theaflavins and catechins. The HSCCC run was carried out with a two-phase solvent system composed of hexane-ethyl acetate-methanol-water-acetic acid (1:5:1:5:0.25, v/v) by eluting the lower aqueous phase at 2 ml/min at 700 rpm. The results indicated that pure theaflavin, theaflavins-3-gallate, theaflavins-3'-gallate and theaflavin-3,3'-digallate could be obtained from crude theaflavins sample and black tea. The structures of the isolated compounds were positively confirmed by (1)H NMR and (13)C NMR, MS analysis, HPLC data and TLC data. Meanwhile, catechins including epigallocatechin gallate, gallocatechin gallate, epicatechin gallate and epigallocatechin were isolated from the aqueous extract of green tea by using the same solvent system. This study developed a modified method combined with enrichment theaflavins method by using HSCCC for separation of four individual theaflavins, especially for better separation of theaflavins monogallates.

Pulsed counter-current ultrasound-assisted extraction and characterization of polysaccharides from Boletus edulis.

PubMed

You, Qinghong; Yin, Xiulian; Ji, Chaowen

2014-01-30

Four methods for extracting polysaccharides from Boletus edulis, namely, hot-water extraction, ultrasonic clearer extraction, static probe ultrasonic extraction, and pulsed counter-current probe ultrasonic extraction (CCPUE), were studied. Results showed that CCPUE has the highest extraction efficiency among the methods studied. Under optimal CCPUE conditions, a B. edulis polysaccharide (BEP) yield of 8.21% was obtained. Three purified fractions, BEP-I, BEP-II, and BEP-III, were obtained through sequential purification by DEAE-52 and Sephadex G-75 chromatography. The average molecular weights of BEP-I, BEP-II, and BEP-III were 10,278, 23,761, and 42,736 Da, respectively. The polysaccharides were mainly composed of xylose, mannose, galactose, and glucose; of these, mannose contents were the highest. The antioxidant activities of the BEPs were further investigated by measurement of their ability to scavenge DPPH and hydroxyl radicals as well as their reducing power. The results indicated that the BEPs have good antioxidant activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

Chromium (Ⅵ) removal from aqueous solutions through powdered activated carbon countercurrent two-stage adsorption.

PubMed

Wang, Wenqiang

2018-01-01

To exploit the adsorption capacity of commercial powdered activated carbon (PAC) and to improve the efficiency of Cr(VI) removal from aqueous solutions, the adsorption of Cr(VI) by commercial PAC and the countercurrent two-stage adsorption (CTA) process was investigated. Different adsorption kinetics models and isotherms were compared, and the pseudo-second-order model and the Langmuir and Freundlich models fit the experimental data well. The Cr(VI) removal efficiency was >80% and was improved by 37% through the CTA process compared with the conventional single-stage adsorption process when the initial Cr(VI) concentration was 50 mg/L with a PAC dose of 1.250 g/L and a pH of 3. A calculation method for calculating the effluent Cr(VI) concentration and the PAC dose was developed for the CTA process, and the validity of the method was confirmed by a deviation of <5%. Copyright © 2017. Published by Elsevier Ltd.

One-step isolation of γ-oryzanol from rice bran oil by non-aqueous hydrostatic countercurrent chromatography.

PubMed

Angelis, Apostolis; Urbain, Aurélie; Halabalaki, Maria; Aligiannis, Nektarios; Skaltsounis, Alexios-Leandros

2011-09-01

The value-added γ-oryzanol was purified in one step from crude rice bran oil (RBO) using a preparative hydrostatic countercurrent chromatography (hydrostatic CCC) method, operating in the dual mode. The fractionation was performed using a non-aqueous biphasic solvent system consisting of heptane-acetonitrile-butanol (1.8:1.4:0.7, v/v/v), leading rapidly to the target compounds. Transfer of the analytical CCC method to large-scale isolation was also carried out yielding a high quantity-high purity fraction of γ-oryzanol. In addition, a fraction of hydroxylated triterpene alcohol ferulates (polar γ-oryzanol) was clearly separated and obtained. Furthermore, a fast HPLC-APCI(±)-HRMS method was developed and applied for the identification of γ-oryzanol as well as the polar γ-oryzanol in RBO and the resulting fractions. The purity of γ-oryzanol fraction was estimated as 97% based on HPLC-APCI-HRMS analysis. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ORGANIC-HIGH IONIC STRENGTH AQUEOUS SOLVENT SYSTEMS FOR SPIRAL COUNTER-CURRENT CHROMATOGRAPHY: GRAPHIC OPTIMIZATION OF PARTITION COEFFICIENT

PubMed Central

Zeng, Yun; Liu, Gang; Ma, Ying; Chen, Xiaoyuan; Ito, Yoichiro

2012-01-01

A new series of organic-high ionic strength aqueous two-phase solvents systems was designed for separation of highly polar compounds by spiral high-speed counter-current chromatography. A total of 21 solvent systems composed of 1-butanol-ethanol-saturated ammonium sulfate-water at various volume ratios are arranged according to an increasing order of polarity. Selection of the two-phase solvent system for a single compound or a multiple sample mixture can be achieved by two steps of partition coefficient measurements using a graphic method. The capability of the method is demonstrated by optimization of partition coefficient for seven highly polar samples including tartrazine (K=0.77), tryptophan (K=1.00), methyl green (K= 0.93), tyrosine (0.81), metanephrine (K=0.89), tyramine (K=0.98), and normetanephrine (K=0.96). Three sulfonic acid components in D&C Green No. 8 were successfully separated by HSCCC using the graphic selection of the two-phase solvent system. PMID:23467197

SOLVENT EXTRACTION PROCESS FOR THE SEPARATION OF URANIUM AND THORIUM FROM PROTACTINIUM AND FISSION PRODUCTS

DOEpatents

Rainey, R.H.; Moore, J.G.

1962-08-14

A liquid-liquid extraction process was developed for recovering thorium and uranium values from a neutron irradiated thorium composition. They are separated from a solvent extraction system comprising a first end extraction stage for introducing an aqueous feed containing thorium and uranium into the system consisting of a plurality of intermediate extractiorr stages and a second end extractron stage for introducing an aqueous immiscible selective organic solvent for thorium and uranium in countercurrent contact therein with the aqueous feed. A nitrate iondeficient aqueous feed solution containing thorium and uranium was introduced into the first end extraction stage in countercurrent contact with the organic solvent entering the system from the second end extraction stage while intro ducing an aqueous solution of salting nitric acid into any one of the intermediate extraction stages of the system. The resultant thorium and uranium-laden organic solvent was removed at a point preceding the first end extraction stage of the system. (AEC)

Metal ion-improved complexation countercurrent chromatography for enantioseparation of dihydroflavone enantiomers.

PubMed

Han, Chao; Wang, Wenli; Xue, Guimin; Xu, Dingqiao; Zhu, Tianyu; Wang, Shanshan; Cai, Pei; Luo, Jianguang; Kong, Lingyi

2018-01-12

Cu(II) ion was selected as an additive to improve the enantioseparation efficiency of three dihydroflavone enantiomers in high-speed counter-current chromatography (HSCCC), using hydroxypropyl-β-cyclodextrin (HP-β-CyD) as the chiral selector. The influences of important parameters, including the metal ion, the concentrations of HP-β-CyD and the Cu(II) ion, and the sample size were investigated. Under optimal conditions, three dihydroflavone enantiomers, including (±)-hesperetin, (±)-naringenin, and (±)-farrerol, were successfully enantioseparated. The chiral recognition mechanism was investigated. The enantioseparation was attributed to the different thermodynamic stabilities of the binary complexes of HP-β-CyD and (±)-hesperetin, and Cu(II) ion could enhance this difference by forming ternary complexes with the binary complexes. This Cu(II) ion-improved complexation HSCCC system exhibited improved performance for chiral separation, and therefore it has great application potential in the preparative enantioseparation of other compounds with similar skeletons. Copyright © 2017 Elsevier B.V. All rights reserved.

Comprehensive separation of secondary metabolites in natural products by high-speed counter-current chromatography using a three-phase solvent system.

PubMed

Yanagida, Akio; Yamakawa, Yutaka; Noji, Ryoko; Oda, Ako; Shindo, Heisaburo; Ito, Yoichiro; Shibusawa, Yoichi

2007-06-01

High-speed counter-current chromatography (HSCCC) using the three-phase solvent system n-hexane-methyl acetate-acetonitrile-water at a volume ratio of 4:4:3:4 was applied to the comprehensive separation of secondary metabolites in several natural product extracts. A wide variety of secondary metabolites in each natural product was effectively extracted with the three-phase solvent system, and the filtered extract was directly submitted to the HSCCC separation using the same three-phase system. In the HSCCC profiles of crude natural drugs listed in the Japanese Pharmacopoeia, several physiologically active compounds were clearly separated from other components in the extracts. The HSCCC profiles of several tea products, each manufactured by a different process, clearly showed their compositional difference in main compounds such as catechins, caffeine, and pigments. These HSCCC profiles also provide useful information about hydrophobic diversity of whole components present in each natural product.

Separation of polyphenols and caffeine from the acetone extract of fermented tea leaves (Camellia sinensis) using high-performance countercurrent chromatography.

PubMed

Choi, Soo Jung; Hong, Yong Deog; Lee, Bumjin; Park, Jun Seong; Jeong, Hyun Woo; Kim, Wan Gi; Shin, Song Seok; Yoon, Kee Dong

2015-07-21

Leaves from Camellia sienensis are a popular natural source of various beverage worldwide, and contain caffeine and polyphenols derived from catechin analogues. In the current study, caffeine (CAF, 1) and three tea polyphenols including (-)-epigallocatechin 3-O-gallate (EGCg, 2), (-)-gallocatechin 3-O-gallate (GCg, 3), and (-)-epicatechin 3-O-gallate (ECg, 4) were isolated and purified by flow-rate gradient high-performance countercurrent chromatography (HPCCC) using a two-phase solvent system composed of n-hexane-ethyl acetate-methanol-water (1:9:1:9, v/v). Two hundred milligrams of acetone-soluble extract from fermented C. sinensis leaves was separated by HPCCC to give 1 (25.4 mg), 2 (16.3 mg), 3 (11.1 mg) and 4 (4.4 mg) with purities over 98%. The structures of 1-4 were elucidated by QTOF-MS, as well as 1H- and 13C-NMR, and the obtained data were compared to the previously reported values.

The mobility and distribution of heavy metals during the formation of first cycle red beds.

USGS Publications Warehouse

Zielinski, R.A.; Bloch, S.; Walker, T.R.

1983-01-01

Analysis of the heavy metal content in a Holocene-Pliocene red bed sequence near San Felipe in N Baja California, Mexico, has yielded new information on the mobility and distribution of these metals during ageing of iron oxyhydroxides from the amorphous to the crystalline state. Whole-rock samples (27) and a series of successive leachates were analysed for V, Al, Cr, Mn, Fe, Co, Ni, Cu and Zn by ICP spectrometry and for U by a delayed neutron technique. These data are supported by a variety of other mineralogical and petrographical observations. The results indicate that the metal content of the samples is predominantly inherited from the constituent detrital minerals. Reddening of the whole-rock samples does not promote major open-system migration of the heavy metals; rather, contained metals redistribute themselves on an intergranular scale, moving from detrital mineral hosts to the secondary iron oxides. The amount of secondary iron oxides and the fraction of whole-rock metals associated with these oxides increase during red-bed development. In addition, the abundance of well- crystallized iron oxides increases during this period. Differences in the leaching efficiency for various metals are related to differences in metal site distribution and intergranular permeability. Inferred conditions for rapid vs limited removal of metals from red beds are summarized. It is suggested that developed red beds which are well flushed by suitable pore fluids may be sources of significant quantities of heavy metals. -J.E.S.

Modeling sediment transport with an integrated view of the biofilm effects

NASA Astrophysics Data System (ADS)

Fang, H. W.; Lai, H. J.; Cheng, W.; Huang, L.; He, G. J.

2017-09-01

Most natural sediment is invariably covered by biofilms in reservoirs and lakes, which have significant influence on bed form dynamics and sediment transport, and also play a crucial role in natural river evolution, pollutant transport, and habitat changes. However, most models for sediment transport are based on experiments using clean sediments without biological materials. In this study, a three-dimensional mathematical model of hydrodynamics and sediment transport is presented with a comprehensive consideration of the biofilm effects. The changes of the bed resistance mainly due to the different bed form dynamics of the biofilm-coated sediment (biosediment), which affect the hydrodynamic characteristics, are considered. Moreover, the variations of parameters related to sediment transport after the biofilm growth are integrated, including the significant changes of the incipient velocity, settling velocity, reference concentration, and equilibrium bed load transport rate. The proposed model is applied to evaluate the effects of biofilms on the hydrodynamic characteristics and sediment transport in laboratory experiments. Results indicate that the mean velocity increases after the biofilm growth, and the turbulence intensity near the river bed decreases under the same flow condition. Meanwhile, biofilm inhibits sediment from moving independently. Thus, the moderate erosion is observed for biosediment resulting in smaller suspended sediment concentrations. The proposed model can reasonably reflect these sediment transport characteristics with biofilms, and the approach to integration of the biological impact could also be used in other modeling of sediment transport, which can be further applied to provide references for the integrated management of natural aqueous systems.

West-Antarctic Ice Streams: Analog to Ice Flow in Channels on Mars

NASA Technical Reports Server (NTRS)

Lucchitta, B. K.

1997-01-01

Sounding of the sea floor in front of the Ross Ice Shelf in Antarctica recently revealed large persistent patterns of longitudinal megaflutes and drumlinoid forms, which are interpreted to have formed at the base of ice streams during the list glacial advance. The flutes bear remarkable resemblance to longitudinal grooves and highly elongated streamlined islands found on the floors of some large martian channels, called outflow channels. ln addition, other similarities exist between Antarctic ice streams and outflow channels. Ice streams are 30 to 80 km wide and hundreds of kilometers long, as are the martian channels. Ice stream beds are below sea level. Floors of many martian outflow channels lie below martian datum, which may have been close to or below past martian sea levels. The Antarctic ice stream bed gradient is flat and locally may go uphill, and surface slopes are exceptionally low. So are gradients of martian channels. The depth to the bed in ice streams is 1 to 1.5 km. At bankful stage, the depth of the fluid in outflow channels would have been 1 to 2 km. These similarities suggest that the martian outflow channels, whose origin is commonly attributed to gigantic catastrophic floods, were locally filled by ice that left a conspicuous morphologic imprint. Unlike the West-Antarctic-ice streams, which discharge ice from an ice sheet, ice in the martian channels came from water erupting from the ground. In the cold martian environment, this water, if of moderate volume, would eventually freeze. Thus it may have formed icings on springs, ice dams and jams on constrictions in the channel path, or frozen pools. Given sufficient thickness and downhill surface gradient, these ice masses would have moved; and given the right conditions, they could have moved like Antarctic ice streams.

Move to improve: the feasibility of using an early mobility protocol to increase ambulation in the intensive and intermediate care settings.

PubMed

Drolet, Anne; DeJuilio, Patti; Harkless, Sherri; Henricks, Sherry; Kamin, Elizabeth; Leddy, Elizabeth A; Lloyd, Joanna M; Waters, Carissa; Williams, Sarah

2013-02-01

Prolonged bed rest in hospitalized patients leads to deconditioning, impaired mobility, and the potential for longer hospital stays. The purpose of this study was to determine the effectiveness of a nurse-driven mobility protocol to increase the percentage of patients ambulating during the first 72 hours of their hospital stay. A quasi-experimental design was used before and after intervention in a 16-bed adult medical/surgical intensive care unit (ICU) and a 26-bed adult intermediate care unit (IMCU) at a large community hospital. A multidisciplinary team developed and implemented a mobility order set with an embedded algorithm to guide nursing assessment of mobility potential. Based on the assessments, the protocol empowers the nurse to consult physical therapists or occupational therapists when appropriate. Daily ambulation status reports were reviewed each morning to determine each patient's activity level. Retrospective and prospective chart reviews were performed to evaluate the effectiveness of the protocol for patients 18 years of age and older who were hospitalized 72 hours or longer. In the 3 months prior to implementation of the Move to Improve project, 6.2% (12 of 193) of the ICU patients and 15.5% (54 of 349) of the IMCU patients ambulated during the first 72 hours of their hospitalization. During the 6 months following implementation, those rates rose to 20.2% (86 of 426) and 71.8% (257 of 358), respectively. The study was carried out at only one center. The initial experience with a nurse-driven mobility protocol suggests that the rate of patient ambulation in an adult ICU and IMCU during the first 72 hours of a hospital stay can be increased.

Sex that moves mountains: The influence of spawning fish on river profiles over geologic timescales

NASA Astrophysics Data System (ADS)

Fremier, Alexander K.; Yanites, Brian J.; Yager, Elowyn M.

2018-03-01

A key component of resilience is to understand feedbacks among components of biophysical systems, such as physical drivers, ecological responses and the subsequent feedbacks onto physical process. While physically based explanations of biological speciation are common (e.g., mountains separating a species can lead to speciation), less common is the inverse process examined: can a speciation event have significant influence on physical processes and patterns in a landscape? When such processes are considered, such as with 'ecosystem engineers', many studies have focused on the short-term physical and biological effects rather than the long-term impacts. Here, we formalized the physical influence of salmon spawning on stream beds into a model of channel profile evolution by altering the critical shear stress required to move stream bed particles. We then asked if spawning and an adaptive radiation event (similar to the one that occurred in Pacific salmon species) could have an effect on channel erosion processes and stream profiles over geological timescales. We found that spawning can profoundly influence the longitudinal profiles of stream beds and thereby the evolution of entire watersheds. The radiation of five Pacific salmon from a common ancestor, additionally, could also cause significant geomorphic change by altering a wider section of the profile for a given distribution of grain sizes. This modeling study suggests that biological evolution can impact landscape evolution by increasing the sediment transport and erosion efficiency of mountain streams. Moreover, the physical effects of a species on its environment might be a complementary explanation for rapid radiation events in species through the creation of new habitat types. This example provides an illustrative case for thinking about the long- and short-term coupling of biotic and abiotic systems.

Pilot-scale Limestone Emission Control (LEC) process: A development project. Volume 1, Main report and appendices A, B, C, and D: Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prudich, M.E.; Appell, K.W.; McKenna, J.D.

ETS, Inc., a pollution consulting firm with headquarters in Roanoke, Virginia, has developed a dry, limestone-based flue gas desulfurization (FGD) system. This SO{sub 2} removal system, called Limestone Emission Control (LEC), can be designed for installation on either new or existing coal-fired boilers. In the LEC process, the SO{sub 2} in the flue gas reacts with wetted granular limestone that is contained in a moving bed. A surface layer of principally calcium sulfate (CaSO{sub 4}) is formed on the limestone. Periodic removal of this surface layer by mechanical agitation allows high utilization of the limestone granules. A nominal 5,000 acfmmore » LEC pilot plant has been designed, fabricated and installed on the slipstream of a 70,000 pph stoker boiler providing steam to Ohio University`s Athens, Ohio campus. A total of over 90 experimental trials have been performed using the pilot-scale moving-bed LEC dry scrubber as a part of this research project with run times ranging up to a high of 125 hours. SO{sub 2} removal efficiencies as high as 99.9% were achievable for all experimental conditions studied during which sufficient humidification was added to the LEC bed. The LEC process and conventional limestone scrubbing have been compared on an equatable basis using flue gas conditions that would be expected at the outlet of the electrostatic precipitator (ESP) of a 500 MW coal-fired power plant. The LEC was found to have a definite economic advantage in both direct capital costs and operating costs. Based on the success and findings of the present project, the next step in LEC process development will be a full-scale commercial demonstration unit.« less

Apparatus and method for solar coal gasification

DOEpatents

Gregg, David W.

1980-01-01

Apparatus for using focused solar radiation to gasify coal and other carbonaceous materials. Incident solar radiation is focused from an array of heliostats onto a tower-mounted secondary mirror which redirects the focused solar radiation down through a window onto the surface of a vertically-moving bed of coal, or a fluidized bed of coal, contained within a gasification reactor. The reactor is designed to minimize contact between the window and solids in the reactor. Steam introduced into the gasification reactor reacts with the heated coal to produce gas consisting mainly of carbon monoxide and hydrogen, commonly called "synthesis gas", which can be converted to methane, methanol, gasoline, and other useful products. One of the novel features of the invention is the generation of process steam at the rear surface of the secondary mirror.

Apparatus for solar coal gasification

DOEpatents

Gregg, D.W.

Apparatus for using focused solar radiation to gasify coal and other carbonaceous materials is described. Incident solar radiation is focused from an array of heliostats onto a tower-mounted secondary mirror which redirects the focused solar radiation down through a window onto the surface of a vertically-moving bed of coal, or a fluidized bed of coal, contained within a gasification reactor. The reactor is designed to minimize contact between the window and solids in the reactor. Steam introduced into the gasification reactor reacts with the heated coal to produce gas consisting mainly of carbon monoxide and hydrogen, commonly called synthesis gas, which can be converted to methane, methanol, gasoline, and other useful products. One of the novel features of the invention is the generation of process steam at the rear surface of the secondary mirror.

Thermal energy storage for solar power generation - State of the art

NASA Astrophysics Data System (ADS)

Shukla, K. N.

1981-12-01

High temperature storage for applications in solar-thermal electric systems is considered. Noting that thermal storage is in either the form of latent, sensible or chemically stored heat, sensible heat storage is stressed as the most developed of the thermal storage technologies, spanning direct heating of a storage medium from 120-1250 C. Current methods involve solids, packed beds, fluidized beds, liquids, hot water, organic liquids, and inorganic liquids and molten salts. Latent heat storage comprises phase-change materials that move from solid to liquid with addition of heat and liquid to solid with the removal of heat. Metals or inorganic salts are candidates, and the energy balances are outlined. Finally, chemical heat storage is examined, showing possible high energy densities through catalytic, thermal dissociation reactions.

Tracking channel bed resiliency in forested mountain catchments using high temporal resolution channel bed movement

NASA Astrophysics Data System (ADS)

Conklin, M. H.; Martin, S.

2017-12-01

This study uses continuous-recording load cell pressure sensors in four, high-elevation (1500-1800 m), Sierra Nevada, headwater streams, to collect high temporal resolution, bedload-movement data for investigating the channel bed movement patterns within these streams for water years 2012-2014. Data show an annual pattern where channel bed material in the thalweg starts to build up in early fall, peaks around peak snow melt, and scours back to baseline levels during hydrograph drawdown and baseflow. This pattern is punctuated by disturbance and recovery of channel bed material associated with short-term, storm events. We propose conceptual model, linking sediment sources at the channel margins to patterns of channel bed fill and scour in the thalweg, based on this and earlier work showing in-stream sources for bedload material. The material in the thalweg represents a balance between sediment supply from the channel margins and sporadic, conveyor-belt-like, downstream transport in the thalweg. The conceptual model highlights not only the importance of production and transport rates but also that seasonal connectedness between the margins and thalweg is a key sediment control, determining both the accumulation rate of sediment stores at the margins, and the redistribution of sediment from margins to thalweg that "feeds" the conveyor-belt. Disturbance and recovery cycles are observed at multiple temporal scales, but long term, the channel beds are stable, suggesting the beds act as short-term storage for sediment, but are in equilibrium interannually. The feasibility of use for these sensors in forested mountain stream environments is tested. Despite a high failure rate (50%), load cell pressure sensors show potential for high-temporal-resolution bedload measurements, allowing for the collection of channel bed movement data to move beyond time-integrated change measurements - where many of the subtleties of bedload movement patterns may be missed - to continuous and/or real-time measurements. This type of high-temporal-resolution data provides insight into short term cycles of bedload movement in high gradient, forested, mountain streams.

Tracking channel bed resiliency in forested mountain catchments using high temporal resolution channel bed movement

NASA Astrophysics Data System (ADS)

Martin, Sarah E.; Conklin, Martha H.

2018-01-01

This study uses continuous-recording load cell pressure sensors in four, high-elevation (1500-1800 m), Sierra Nevada headwater streams to collect high-temporal-resolution, bedload-movement data for investigating the channel bed movement patterns within these streams for water years 2012-2014. Data show an annual pattern where channel bed material in the thalweg starts to build up in early fall, peaks around peak snow melt, and scours back to baseline levels during hydrograph drawdown and base flow. This pattern is punctuated by disturbance and recovery of channel bed material associated with short-term storm events. A conceptual model, linking sediment sources at the channel margins to patterns of channel bed fill and scour in the thalweg, is proposed building on the results of Martin et al. (2014). The material in the thalweg represents a balance between sediment supply from the channel margins and sporadic, conveyor-belt-like downstream transport in the thalweg. The conceptual model highlights not only the importance of production and transport rates but also that seasonal connectedness between the margins and thalweg is a key sediment control, determining the accumulation rate of sediment stores at the margins and the redistribution of sediment from margins to thalweg that feeds the conveyor belt. Disturbance and recovery cycles are observed at multiple temporal scales; but long term, the channel beds are stable, suggesting that the beds act as short-term storage for sediment but are in equilibrium interannually. The feasibility of use for these sensors in forested mountain stream environments is tested. Despite a high failure rate (50%), load cell pressure sensors show potential for high-temporal-resolution bedload measurements, allowing for the collection of channel bed movement data to move beyond time-integrated change measurements - where many of the subtleties of bedload movement patterns may be missed - to continuous and/or real-time measurements. This type of high-temporal-resolution data provides insight into short-term cycles of bedload movement in high gradient, forested mountain streams.

ARC-2006-ACD06-0177-011

NASA Image and Video Library

2006-10-18

Ames Hypersonic Free Flight Aerodynamic Facility is used for research on gas dynamic problems of atmospheric entry. High relative speeds are achieved by launching models (in sabots if necessary) from high-speed guns into a countercurrent hypersonic air stream (14,000 ft/sec) driven by combustion-powered shock tube.

MICROBIAL COMETABOLISM OF RECALCITRANT CHEMICALS IN CONTAMINATED AIR STREAMS

EPA Science Inventory

Chlorinated Solvents: The treatment system consists of a laboratory-scale hollow fiber membrane (HFM) module containing a center baffle and a radial cross-flow pattern on the shell side of the fibers. The shell and lumen fluids are contacting in a counter-current f...

A New Method for Tracking Individual Particles During Bed Load Transport in a Gravel-Bed River

NASA Astrophysics Data System (ADS)

Tremblay, M.; Marquis, G. A.; Roy, A. G.; Chaire de Recherche Du Canada En Dynamique Fluviale

2010-12-01

Many particle tracers (passive or active) have been developed to study gravel movement in rivers. It remains difficult, however, to document resting and moving periods and to know how particles travel from one deposition site to another. Our new tracking method uses the Hobo Pendant G acceleration Data Logger to quantitatively describe the motion of individual particles from the initiation of movement, through the displacement and to the rest, in a natural gravel river. The Hobo measures the acceleration in three dimensions at a chosen temporal frequency. The Hobo was inserted into 11 artificial rocks. The rocks were seeded in Ruisseau Béard, a small gravel-bed river in the Yamaska drainage basin (Québec) where the hydraulics, particle sizes and bed characteristics are well known. The signals recorded during eight floods (Summer and Fall 2008-2009) allowed us to develop an algorithm which classifies the periods of rest and motion. We can differentiate two types of motion: sliding and rolling. The particles can also vibrate while remaining in the same position. The examination of the movement and vibration periods with respect to the hydraulic conditions (discharge, shear stress, stream power) showed that vibration occurred mostly before the rise of hydrograph and allowed us to establish movement threshold and response times. In all cases, particle movements occurred during floods but not always in direct response to increased bed shear stress and stream power. This method offers great potential to track individual particles and to establish a spatiotemporal sequence of the intermittent transport of the particle during a flood and to test theories concerning the resting periods of particles on a gravel bed.

Resource Recovery Technology Application Document.

DTIC Science & Technology

1982-06-01

B-6 Electrostatic Precipitator (APC-C) ......................B-1O Venturi Scrubber (APC D) B-15 C Combustion Equipment (CE) C-1 Modular... Scrubber APC-D P. 1 of 4 CONTROLIII COMPONENT DESCRIPTION Types Available - Competing Components Type a. Venturi e. Moving bed Venturi b. Flooded disc f...Clean Gas to Demister (Used Separate Liquid from Gas Stream) / F C Scrubber Wall Liquid Inlet D Scrubber Liquid at Venturi Throat Inlet B E Venturi

Model-based identification of optimal operating conditions for amino acid simulated moving bed enantioseparation using a macrocyclic glycopeptide stationary phase.

PubMed

Fuereder, Markus; Majeed, Imthiyas N; Panke, Sven; Bechtold, Matthias

2014-06-13

Teicoplanin aglycone columns allow efficient separation of amino acid enantiomers in aqueous mobile phases and enable robust and predictable simulated moving bed (SMB) separation of racemic methionine despite a dependency of the adsorption behavior on the column history (memory effect). In this work we systematically investigated the influence of the mobile phase (methanol content) and temperature on SMB performance using a model-based optimization approach that accounts for methionine solubility, adsorption behavior and back pressure. Adsorption isotherms became more favorable with increasing methanol content but methionine solubility was decreased and back pressure increased. Numerical optimization suggested a moderate methanol content (25-35%) for most efficient operation. Higher temperature had a positive effect on specific productivity and desorbent requirement due to higher methionine solubility, lower back pressure and virtually invariant selectivity at high loadings of racemic methionine. However, process robustness (defined as a difference in flow rate ratios) decreased strongly with increasing temperature to the extent that any significant increase in temperature over 32°C will likely result in operating points that cannot be realized technically even with the lab-scale piston pump SMB system employed in this study. Copyright © 2014. Published by Elsevier B.V.

Kinetic energy density and agglomerate abrasion rate during blending of agglomerates into powders.

PubMed

Willemsz, Tofan A; Hooijmaijers, Ricardo; Rubingh, Carina M; Tran, Thanh N; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees

2012-01-23

Problems related to the blending of a cohesive powder with a free flowing bulk powder are frequently encountered in the pharmaceutical industry. The cohesive powder often forms lumps or agglomerates which are not dispersed during the mixing process and are therefore detrimental to blend uniformity. Achieving sufficient blend uniformity requires that the blending conditions are able to break up agglomerates, which is often an abrasion process. This study was based on the assumption that the abrasion rate of agglomerates determines the required blending time. It is shown that the kinetic energy density of the moving powder bed is a relevant parameter which correlates with the abrasion rate of agglomerates. However, aspects related to the strength of agglomerates should also be considered. For this reason the Stokes abrasion number (St(Abr)) has been defined. This parameter describes the ratio between the kinetic energy density of the moving powder bed and the work of fracture of the agglomerate. The St(Abr) number is shown to predict the abrasion potential of agglomerates in the dry-mixing process. It appeared possible to include effects of filler particle size and impeller rotational rate into this concept. A clear relationship between abrasion rate of agglomerates and the value of St(Abr) was demonstrated. Copyright © 2011 Elsevier B.V. All rights reserved.

Measuring and modeling the oxygen profile in a nitrifying Moving Bed Biofilm Reactor.

PubMed

Masić, Alma; Bengtsson, Jessica; Christensson, Magnus

2010-09-01

In this paper we determine the oxygen profile in a biofilm on suspended carriers in two ways: firstly by microelectrode measurements and secondly by a simple mathematical model. The Moving Bed Biofilm Reactor is well-established for wastewater treatment where bacteria grow as a biofilm on the protective surfaces of suspended carriers. The flat shaped BiofilmChip P was developed to allow good conditions for transport of substrates into the biofilm. The oxygen profile was measured in situ the nitrifying biofilm with a microelectrode and it was simulated with a one-dimensional mathematical model. We extended the model by adding a CSTR equation, to connect the reactor to the biofilm through the boundary conditions. We showed the dependence of the thickness of the mass transfer boundary layer on the bulk flow rate. Finally, we estimated the erosion parameter lambda to increase the concordance between the measured and simulated profiles. This lead to a simple empirical relationship between lambda and the flow rate. The data gathered by in situ microelectrode measurements can, together with the mathematical model, be used in predictive modeling and give more insight in the design of new carriers, with the ambition of making process operation more energy efficient. Copyright 2010 Elsevier Inc. All rights reserved.

An integrated mathematical model for chemical oxygen demand (COD) removal in moving bed biofilm reactors (MBBR) including predation and hydrolysis.

PubMed

Revilla, Marta; Galán, Berta; Viguri, Javier R

2016-07-01

An integrated mathematical model is proposed for modelling a moving bed biofilm reactor (MBBR) for removal of chemical oxygen demand (COD) under aerobic conditions. The composite model combines the following: (i) a one-dimensional biofilm model, (ii) a bulk liquid model, and (iii) biological processes in the bulk liquid and biofilm considering the interactions among autotrophic, heterotrophic and predator microorganisms. Depending on the values for the soluble biodegradable COD loading rate (SCLR), the model takes into account a) the hydrolysis of slowly biodegradable compounds in the bulk liquid, and b) the growth of predator microorganisms in the bulk liquid and in the biofilm. The integration of the model and the SCLR allows a general description of the behaviour of COD removal by the MBBR under various conditions. The model is applied for two in-series MBBR wastewater plant from an integrated cellulose and viscose production and accurately describes the experimental concentrations of COD, total suspended solids (TSS), nitrogen and phosphorous obtained during 14 months working at different SCLRs and nutrient dosages. The representation of the microorganism group distribution in the biofilm and in the bulk liquid allow for verification of the presence of predator microorganisms in the second reactor under some operational conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Organic matter degradation in a greywater recycling system using a multistage moving bed biofilm reactor (MBBR).

PubMed

Saidi, Assia; Masmoudi, Khaoula; Nolde, Erwin; El Amrani, Btissam; Amraoui, Fouad

2017-12-01

Greywater is an important non-conventional water resource which can be treated and recycled in buildings. A decentralized greywater recycling system for 223 inhabitants started operating in 2006 in Berlin, Germany. High load greywater undergoes advanced treatment in a multistage moving bed biofilm reactor (MBBR) followed by sand filtration and UV disinfection. The treated water is used safely as service water for toilet flushing. Monitoring of the organic matter degradation was pursued to describe the degradation processes in each stage and optimize the system. Results showed that organic matter reduction was achieved for the most part in the first three reactors, whereas the highest reduction rate was observed in the third reactor in terms of COD (chemical oxygen demand), dissolved organic carbon and BOD 7 (biological oxygen demand). The results also showed that the average loading rate entering the system was 3.7 kg COD/d, while the removal rate was 3.4 kg COD/d in a total bioreactor volume of 11.7 m³. In terms of BOD, the loading rate was 2.8 kg BOD/d and it was almost totally removed. This system requires little space (0.15 m²/person) and maintenance work of less than one hour per month and it shows operational stability under peak loads.

Carrier effects on tertiary nitrifying moving bed biofilm reactor: An examination of performance, biofilm and biologically produced solids.

PubMed

Forrest, Daina; Delatolla, Robert; Kennedy, Kevin

2016-01-01

Increasingly stricter ammonia and nitrogen release regulations with respect to wastewater effluents are creating a need for tertiary treatment systems. The moving bed biofilm reactor (MBBR) is being considered as an upgrade option for an increasing number of wastewater treatment facilities due to its small footprint and ease of operation. Despite the MBBRs creation as a system to remove nitrogen, recent research on MBBR systems showing that the system's performance is directly related to carrier surface area and is irrespective of carrier shape and type has been performed exclusively on chemical oxygen demand (COD) removal systems. Furthermore, the influence of carrier type on the solids produced by MBBR systems has also been exclusively studied for COD removal systems. This work investigates the effects of three specific carrier types on ammonia removal rates, biofilm morphology, along with solids production and settleability of tertiary nitrifying MBBR systems. The study concludes that carrier type has no significant effect on tertiary nitrifying MBBR system performance under steady, moderate loading conditions. The research does however highlight the propensity of greater surface area to volume carriers to become clogged under high loading conditions and that the high surface area carriers investigated in this study required longer adjustment periods to changes in loading after becoming clogged.

Start-up of membrane bioreactor and hybrid moving bed biofilm reactor-membrane bioreactor: kinetic study.

PubMed

Leyva-Díaz, J C; Poyatos, J M

2015-01-01

A hybrid moving bed biofilm reactor-membrane bioreactor (hybrid MBBR-MBR) system was studied as an alternative solution to conventional activated sludge processes and membrane bioreactors. This paper shows the results obtained from three laboratory-scale wastewater treatment plants working in parallel in the start-up and steady states. The first wastewater treatment plant was a MBR, the second one was a hybrid MBBR-MBR system containing carriers both in anoxic and aerobic zones of the bioreactor (hybrid MBBR-MBRa), and the last one was a hybrid MBBR-MBR system which contained carriers only in the aerobic zone (hybrid MBBR-MBRb). The reactors operated with a hydraulic retention time of 30.40 h. A kinetic study for characterizing heterotrophic biomass was carried out and organic matter and nutrients removals were evaluated. The heterotrophic biomass of the hybrid MBBR-MBRb showed the best kinetic performance in the steady state, with yield coefficient for heterotrophic biomass=0.30246 mg volatile suspended solids per mg chemical oxygen demand, maximum specific growth rate for heterotrophic biomass=0.00308 h(-1) and half-saturation coefficient for organic matter=3.54908 mg O2 L(-1). The removal of organic matter was supported by the kinetic study of heterotrophic biomass.

Three-Dimensional Stratification of Bacterial Biofilm Populations in a Moving Bed Biofilm Reactor for Nitritation-Anammox

PubMed Central

Almstrand, Robert; Persson, Frank; Daims, Holger; Ekenberg, Maria; Christensson, Magnus; Wilén, Britt-Marie; Sörensson, Fred; Hermansson, Malte

2014-01-01

Moving bed biofilm reactors (MBBRs) are increasingly used for nitrogen removal with nitritation-anaerobic ammonium oxidation (anammox) processes in wastewater treatment. Carriers provide protected surfaces where ammonia oxidizing bacteria (AOB) and anammox bacteria form complex biofilms. However, the knowledge about the organization of microbial communities in MBBR biofilms is sparse. We used new cryosectioning and imaging methods for fluorescence in situ hybridization (FISH) to study the structure of biofilms retrieved from carriers in a nitritation-anammox MBBR. The dimensions of the carrier compartments and the biofilm cryosections after FISH showed good correlation, indicating little disturbance of biofilm samples by the treatment. FISH showed that Nitrosomonas europaea/eutropha-related cells dominated the AOB and Candidatus Brocadia fulgida-related cells dominated the anammox guild. New carriers were initially colonized by AOB, followed by anammox bacteria proliferating in the deeper biofilm layers, probably in anaerobic microhabitats created by AOB activity. Mature biofilms showed a pronounced three-dimensional stratification where AOB dominated closer to the biofilm-water interface, whereas anammox were dominant deeper into the carrier space and towards the walls. Our results suggest that current mathematical models may be oversimplifying these three-dimensional systems and unless the multidimensionality of these systems is considered, models may result in suboptimal design of MBBR carriers. PMID:24481066

Start-up of two moving bed membrane bioreactors treating saline wastewater contaminated by hydrocarbons.

PubMed

Campo, R; Di Prima, N; Freni, G; Giustra, M G; Di Bella, G

2016-01-01

This work aims to assess the acclimation of microorganisms to a gradual increase of salinity and hydrocarbons, during the start-up of two moving bed membrane bioreactors (MB-MBRs) fed with saline oily wastewater. In both systems an ultrafiltration membrane was used and two types of carriers were employed: polyurethane sponge cubes (MB-MBRI) and polyethylene cylindrical carriers (MB-MBRII). A decreasing dilution factor of slops has been adopted in order to allow biomass acclimation. The simultaneous effect of salinity and hydrocarbons played an inhibitory role in biomass growth and this resulted in a decrease of the biological removal efficiencies. A reduction of bound extracellular polymeric substances and a simultaneous release of soluble microbial products (SMPs) were observed, particularly in the MB-MBRII system, probably due to the occurrence of a greater suspended biomass stress as response to the recalcitrance of substrate. On the one hand, a clear attachment of biomass occurred only in MB-MBRI and this affected the fouling deposition on the membrane surface. The processes of detachment and entrapment of biomass, from and into the carriers, significantly influenced the superficial cake deposition and its reversibility. On the other hand, in MB-MBRII, the higher production of SMPs implied a predominance of the pore blocking.

Successional development of biofilms in moving bed biofilm reactor (MBBR) systems treating municipal wastewater.

PubMed

Biswas, Kristi; Taylor, Michael W; Turner, Susan J

2014-02-01

Biofilm-based technologies, such as moving bed biofilm reactor (MBBR) systems, are widely used to treat wastewater. Biofilm development is important for MBBR systems as much of the microbial biomass is retained within reactors as biofilm on suspended carriers. Little is known about this process of biofilm development and the microorganisms upon which MBBRs rely. We documented successional changes in microbial communities as biofilms established in two full-scale MBBR systems treating municipal wastewater over two seasons. 16S rRNA gene-targeted pyrosequencing and clone libraries were used to describe microbial communities. These data indicate a successional process that commences with the establishment of an aerobic community dominated by Gammaproteobacteria (up to 52 % of sequences). Over time, this community shifts towards dominance by putatively anaerobic organisms including Deltaproteobacteria and Clostridiales. Significant differences were observed between the two wastewater treatment plants (WWTPs), mostly due to a large number of sequences (up to 55 %) representing Epsilonproteobacteria (mostly Arcobacter) at one site. Archaea in young biofilms included several lineages of Euryarchaeota and Crenarchaeota. In contrast, the mature biofilm consisted entirely of Methanosarcinaceae (Euryarchaeota). This study provides new insights into the community structure of developing biofilms at full-scale WWTPs and provides the basis for optimizing MBBR start-up and operational parameters.

Decolourization of remazol black-5 textile dyes using moving bed bio-film reactor

NASA Astrophysics Data System (ADS)

Pratiwi, R.; Notodarmojo, S.; Helmy, Q.

2018-01-01

The desizing and dyeing processes in the textile industries produces wastewaster containing high concentration of organic matter and colour, so it needs treatment before released to environment. In this research, removal of azo dye (Remazol Black 5/RB 5) and organic as COD was performed using Moving Bed Biofilm Reactor (MBBR). MBBR is biological treatment process with attached growth media system that can increase removal of organic matter in textile wastewater. The effectiveness of ozonation as pre-treatment process to increase the removal efficiency in MBBR was studied. The results showed that in MBBR batch system with detention time of 1 hour, pre-treatment with ozonation prior to MBBR process able to increase the colour removal efficiency of up to 86.74%. While on the reactor without ozone pre-treatment, the colour removal efficiency of up to 68.6% was achieved. From the continuous reactor experiments found that both colour and COD removal efficiency depends on time detention of RB-5 dyes in the system. The higher of detention time, the higher of colour and COD removal efficiency. It was found that optimum removal of colour and COD was achieved in 24 hour detention time with its efficiency of 96.9% and 89.13%, respectively.

Possible change in distribution of seaweed, Sargassum horneri, in northeast Asia under A2 scenario of global warming and consequent effect on some fish.

PubMed

Komatsu, Teruhisa; Fukuda, Masahiro; Mikami, Atsuko; Mizuno, Shizuha; Kantachumpoo, Attachai; Tanoue, Hideaki; Kawamiya, Michio

2014-08-30

Global warming effects on seaweed beds are already perceptible. Their geographical distributions greatly depend on water temperatures. To predict future geographical distributions of brown alga, Sargassum horneri, forming large beds in the northwestern Pacific, we referred to future monthly surface water temperatures at about 1.1° of longitude and 0.6° of latitude in February and August in 2050 and 2100 simulated by 12 organizations under an A2 scenario of global warming. The southern limit of S. horneri distribution is expected to keep moving northward such that it may broadly disappear from Honshu Island, the Chinese coast, and Korean Peninsula in 2100, when tropical Sargassum species such as Sargassum tenuifolium may not completely replace S. horneri. Thus, their forests in 2100 do not substitute those of S. horneri in 2000. Fishes using the beds and seaweed rafts consisting of S. horneri in East China Sea suffer these disappearances. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Postural responses of head and foot cutaneous microvascular flow and their sensitivity to bed rest

NASA Technical Reports Server (NTRS)

Aratow, Michael; Hargens, Alan R.; Meyer, J.-UWE; Arnaud, Sara B.

1991-01-01

To explore the mechanism for facial puffiness, headache, and nasal congestion associated with microgravity and cephalad fluid shifts, the postural responses of the cutaneous microcirculation (CMC) in the forehead and dorsum of the foot of eight healthy men were studied by changing body position on a tilt table and measuring blood flows with a laser Doppler flowmeter. Increasing arterial pressure in the feet by moving from a -6-deg head-down tilt to a 60-deg head-up posture decreased foot CMC by 46.5 + or - 12.0 percent. Raising arterial pressure in the head increased forehead CMC by 25.5 + or - 0.7 percent (p less than 0.05). To investigate the possibility that these opposite responses could be modified by simulated microgravity, tilt test were repeated after 7 d of -6-deg head-down-tilt bed rest. The responses were not significantly different from those recorded before bed rest. Therefore, CMC in the feet is well regulated to prevent edema when shifting to an upright position, whereas there is less regulation in the head CMC.

Laboratory evaluation of an OTT acoustic digital current meter and a SonTek Laboratory acoustic Doppler velocimeter

USGS Publications Warehouse

Vermeyen, T.B.; Oberg, Kevin A.; Jackson, Patrick Ryan

2009-01-01

Recently, an acoustic current meter known as the OTT * acoustic digital current meter (ADC) was introduced as an alternative instrument for stream gaging measurements. The Bureau of Reclamation and the U.S. Geological Survey collaborated on a side- by-side evaluation of the ADC and a SonTek/YSI acoustic Doppler velocimeter (ADV). Measurements were carried out in a laboratory flume to evaluate the performance characteristics of the ADC under a range of flow and boundary conditions. The flume contained a physical model of a mountain river with a diversion dam and variety of bed materials ranging from smooth mortar to a cobble bed. The instruments were installed on a trolley system that allowed them to be easily moved within the flume while maintaining a consistent probe orientation. More than 50 comparison measurements were made in an effort to verify the manufacturer’s performance specifications and to evaluate potential boundary disturbance for near-bed and vertical boundary measurements. Data and results from this evaluation are presented and discussed. 

Integrated lunar materials manufacturing process

NASA Technical Reports Server (NTRS)

Gibson, Michael A. (Inventor); Knudsen, Christian W. (Inventor)

1990-01-01

A manufacturing plant and process for production of oxygen on the moon uses lunar minerals as feed and a minimum of earth-imported, process materials. Lunar feed stocks are hydrogen-reducible minerals, ilmenite and lunar agglutinates occurring in numerous, explored locations mixed with other minerals in the pulverized surface layer of lunar soil known as regolith. Ilmenite (FeTiO.sub.3) and agglutinates contain ferrous (Fe.sup.+2) iron reducible by hydrogen to yield H.sub.2 O and metallic Fe at about 700.degree.-1,200.degree. C. The H.sub.2 O is electrolyzed in gas phase to yield H.sub.2 for recycle and O.sub.2 for storage and use. Hydrogen losses to lunar vacuum are minimized, with no net hydrogen (or any other earth-derived reagent) consumption except for small leaks. Feed minerals are surface-mined by front shovels and transported in trucks to the processing area. The machines are manned or robotic. Ilmenite and agglutinates occur mixed with silicate minerals which are not hydrogen-reducible at 700.degree.-1,200.degree. C. and consequently are separated and concentrated before feeding to the oxygen generation process. Solids rejected from the separation step and reduced solids from the oxygen process are returned to the mine area. The plant is powered by nuclear or solar power generators. Vapor-phase water electrolysis, a staged, countercurrent, fluidized bed reduction reactor and a radio-frequency-driven ceramic gas heater are used to improve thermal efficiency.

Performance analyses of helical coil heat exchangers. The effect of external coil surface modification on heat exchanger effectiveness

NASA Astrophysics Data System (ADS)

Andrzejczyk, Rafał; Muszyński, Tomasz

2016-12-01

The shell and coil heat exchangers are commonly used in heating, ventilation, nuclear industry, process plant, heat recovery and air conditioning systems. This type of recuperators benefits from simple construction, the low value of pressure drops and high heat transfer. In helical coil, centrifugal force is acting on the moving fluid due to the curvature of the tube results in the development. It has been long recognized that the heat transfer in the helical tube is much better than in the straight ones because of the occurrence of secondary flow in planes normal to the main flow inside the helical structure. Helical tubes show good performance in heat transfer enhancement, while the uniform curvature of spiral structure is inconvenient in pipe installation in heat exchangers. Authors have presented their own construction of shell and tube heat exchanger with intensified heat transfer. The purpose of this article is to assess the influence of the surface modification over the performance coefficient and effectiveness. The experiments have been performed for the steady-state heat transfer. Experimental data points were gathered for both laminar and turbulent flow, both for co current- and countercurrent flow arrangement. To find optimal heat transfer intensification on the shell-side authors applied the number of transfer units analysis.

Reproductive Potential of Salmon Spawning Substrates Inferred from Grain Size and Fish Length

NASA Astrophysics Data System (ADS)

Riebe, C. S.; Sklar, L. S.; Overstreet, B. T.; Wooster, J. K.; Bellugi, D. G.

2014-12-01

The river restoration industry spends millions of dollars every year on improving salmon spawning in riverbeds where sediment is too big for fish to move and thus use during redd building. However, few studies have addressed the question of how big is too big in salmon spawning substrates. Hence managers have had little quantitative basis for gauging the amount of spawning habitat in coarse-bedded rivers. Moreover, the scientific framework has remained weak for restoration projects that seek to improve spawning conditions. To overcome these limitations, we developed a physically based, field-calibrated model for the fraction of the bed that is fine-grained enough to support spawning by fish of a given size. Model inputs are fish length and easy-to-measure indices of bed-surface grain size. Model outputs include the number of redds and eggs the substrate can accommodate when flow depth, temperature, and other environmental factors are not limiting. The mechanistic framework of the model captures the biophysical limits on sediment movement and the space limitations on redd building and egg deposition in riverbeds. We explored the parameter space of the model and found a previously unrecognized tradeoff in salmon size: bigger fish can move larger sediment and thus use more riverbed area for spawning; they also tend to have higher fecundity, and so can deposit more eggs per redd; however, because redd area increases with fish length, the number of eggs a substrate can accommodate is highest for moderate-sized fish. One implication of this tradeoff is that differences in grain size may help regulate river-to-river differences in salmon size. Thus, our model suggests that population diversity and, by extension, species resilience are linked to lithologic, geomorphic, and climatic factors that determine grain size in rivers. We cast the model into easy-to-use look-up tables, charts, and computer applications, including a JavaScript app that works on tablets and mobile phones. We explain how these tools can be used in a new, mechanistic approach to assessing spawning substrates and optimizing gravel augmentation projects in coarse-bedded rivers.

Modeling wood dynamics, jam formation, and sediment storage in a gravel-bed stream

NASA Astrophysics Data System (ADS)

Eaton, B. C.; Hassan, M. A.; Davidson, S. L.

2012-12-01

In small and intermediate sized streams, the interaction between wood and bed material transport often determines the nature of the physical habitat, which in turn influences the health of the stream's ecosystem. We present a stochastic model that can be used to simulate the effects on physical habitat of forest fires, climate change, and other environmental disturbances that alter wood recruitment. The model predicts large wood (LW) loads in a stream as well as the volume of sediment stored by the wood; while it is parameterized to describe gravel bed streams similar to a well-studied field prototype, Fishtrap Creek, British Columbia, it can be calibrated to other systems as well. In the model, LW pieces are produced and modified over time as a result of random tree-fall, LW breakage, LW movement, and piece interaction to form LW jams. Each LW piece traps a portion of the annual bed material transport entering the reach and releases the stored sediment when the LW piece is entrained and moved. The equations governing sediment storage are based on a set of flume experiments also scaled to the field prototype. The model predicts wood loads ranging from 70 m3/ha to more than 300 m3/ha, with a mean value of 178 m3/ha: both the range and the mean value are consistent with field data from streams with similar riparian forest types and climate. The model also predicts an LW jam spacing that is consistent with field data. Furthermore, our modeling results demonstrate that the high spatial and temporal variability in sediment storage, sediment transport, and channel morphology associated with LW-dominated streams occurs only when LW pieces interact and form jams. Model runs that do not include jam formation are much less variable. These results suggest that river restoration efforts using engineered LW pieces that are fixed in place and not permitted to interact will be less successful at restoring the geomorphic processes responsible for producing diverse, productive physical habitats than efforts using LW pieces that are free to move, interact, and form LW jams.

Assessment of elemental mobility in soil using a fluidised bed approach with on-line ICP-MS analysis.

PubMed

Beeston, Michael Philip; Glass, Hylke Jan; van Elteren, Johannes Teun; Slejkovec, Zdenka

2007-09-19

A new method has been developed to analyse the mobility of elements within soils employing counter-current flow soil contacting in a fluidised bed (FB) column. This method alleviates the problem of irreproducible peaks suffered by state-of-the-art micro-column techniques as a result of particle compaction. Reproducible extraction profiles are produced through the leaching of soil with a linear gradient of 0.05 mol L(-1) ammonium sulphate to 0.11 mol L(-1) acetic acid using a high pressure liquid chromatography (HPLC) quaternary pump, and the continuous monitoring of the elements in the leachate with inductively coupled plasma mass spectrometry (ICP-MS). Quantification of the procedure is achieved with an external flow injection (FI) calibration method. Flow rate and FB column length were investigated as critical parameters to the efficiency of the extraction methodology. It was found that an increase in the column length from 10 to 20 cm using a flow rate of 0.15 mL min(-1) produced the same increase in extracted elemental concentration as an increase in flow rate from 0.15 to 0.30 mL min(-1). In both examples, the increase in the concentration of elements leached from the soil may be ascribed to the increase in the concentration gradient between the solid and liquid. The exhaustive nature of the technique defines the maximum leachable concentration within the operationally defined leaching parameters of the exchangeable phase, providing a more accurate assessment of the risk associated with the elements in the soil for the phase providing the greatest risk to the environment. The multi-elemental high sensitivity nature of the on-line detector provides an accurate determination of the associations present between the elements in the soil, and the identification of multiple phases within the exchangeable phase through the presence of multiple peaks in the extraction profiles. It is possible through the deconvolution of these extraction profiles that the concentration corresponding to the peaks identified can be defined.

Grain velocity of bedload movement in an armored non-uniform mobile bed

NASA Astrophysics Data System (ADS)

Liu, C.

2015-12-01

The velocity of bedload particles, which directly reflects the interaction between flow and sediment, is one of the important parameters to predict sediment transport rate, is also one of the fundamental problems for sediment transport. Many excellent works have been accomplished in this filed. However, the existing researches are mostly based on the artificial fixed bed, few moveable bed studies are focus on uniform sediment bed, these boundary conditions are different from a real river. In this research, an experiment on non-uniform sediment with an armored, moveable bed were carried out in a flume, the range of bed material is from 0.2mm to 20mm. With a special hanging glass and illumination system, the motion particles in the bed were clearly shoot on top of the flume by a video camera, avoiding the interference of waves at the flow surface. The speed of the camera is 50 frames per second. About 7000 unique coordinates of moving particles were determined from 3000 frames of successive pictures, the particle velocity of longitudinal and crosswise directions were obtained from the coordinates. The results show that, the probability density distribution of grain velocities of both directions are similar to that in the uniform sediment, which have an exponent decay trend, whereas the value of cross velocity of particles is clearly greater than that in the uniform sediment condition. Negative particle velocity was recognized in the experiment, it is shown that these negative may occur at two conditions, one is the backflow of fine particles behind the coarser particles, and the other is a state of movement change, such as a particle from static state to motion or vice versa. Furthermore, the particle movement was strongly affected by the arrangement of local coarse particles. The influence of coarser particles to the movement of fine particles also identified by two opposite effects, one is the acceleration effects in a 'tunnel' between pair of series particles, the other is the deceleration effects out of the tunnel, or fine particles captured by the backwater flow just behind a coarse particle. In addition, ensemble particle velocity in the armored bed is distinctly less than which in the fixed bed and uniform bed condition with same particle Reynolds number and Shields parameter. (Supported by(2012BAB04B01;NSFC(11472310))

Countercurrent extraction of soluble sugars from almond hulls and assessment of the bioenergy potential

USDA-ARS?s Scientific Manuscript database

Almond hulls contain considerable proportions (37 % by dry weight) of water soluble, fermentable sugars (sucrose, glucose, fructose) which can be extracted for industrial purposes. Optimization found that 20 % solids content was the maximum practical solids/liquor ratio for sugar extraction and tha...

How to Use Chromatography as a Science Teaching Aid.

ERIC Educational Resources Information Center

Ganis, Frank M.

Presented are five procedures which permit the effective teaching of chromatography with equipment which is readily available, economical, and simple in design. The first procedure involves a study of solute partition in two immiscible solvents and of countercurrent distribution. The second illustrates the use of unidimensional ascending paper…

Run-of-River Impoundments Can Remain Unfilled While Transporting Gravel Bedload: Numerical Modeling Results

NASA Astrophysics Data System (ADS)

Pearson, A.; Pizzuto, J. E.

2015-12-01

Previous work at run-of-river (ROR) dams in northern Delaware has shown that bedload supplied to ROR impoundments can be transported over the dam when impoundments remain unfilled. Transport is facilitated by high levels of sand in the impoundment that lowers the critical shear stresses for particle entrainment, and an inversely sloping sediment ramp connecting the impoundment bed (where the water depth is typically equal to the dam height) with the top of the dam (Pearson and Pizzuto, in press). We demonstrate with one-dimensional bed material transport modeling that bed material can move through impoundments and that equilibrium transport (i.e., a balance between supply to and export from the impoundment, with a constant bed elevation) is possible even when the bed elevation is below the top of the dam. Based on our field work and previous HEC-RAS modeling, we assess bed material transport capacity at the base of the sediment ramp (and ignore detailed processes carrying sediment up and ramp and over the dam). The hydraulics at the base of the ramp are computed using a weir equation, providing estimates of water depth, velocity, and friction, based on the discharge and sediment grain size distribution of the impoundment. Bedload transport rates are computed using the Wilcock-Crowe equation, and changes in the impoundment's bed elevation are determined by sediment continuity. Our results indicate that impoundments pass the gravel supplied from upstream with deep pools when gravel supply rate is low, gravel grain sizes are relatively small, sand supply is high, and discharge is high. Conversely, impoundments will tend to fill their pools when gravel supply rate is high, gravel grain sizes are relatively large, sand supply is low, and discharge is low. The rate of bedload supplied to an impoundment is the primary control on how fast equilibrium transport is reached, with discharge having almost no influence on the timing of equilibrium.

River channel bars and dunes - Theory of kinematic waves

USGS Publications Warehouse

Langbein, Walter Basil; Leopold, Luna Bergere

1968-01-01

A kinematic wave is a grouping cf moving objects in zones along a flow path and through which the objects pass. These concentrations may be characterized by a simple relation between the speed of the moving objects and their spacing as a result of interaction between them.Vehicular traffic has long been known to have such properties. Data are introduced to show that beads carried by flowing water in a narrow flume behave in an analogous way. The flux or transport of objects in a single lane of traffic is greatest when the objects are spaced about two diameters apart; beads in a single-lane flume as well as highway traffic conform to this property.By considering the sand in a pipe or flume to a depth affected by dune movement, it is shown that flux-concentration curves similar to the previously known cases can be constructed from experimental data. From the kinematic point of view, concentration of particles in dunes and other wave bed forms results when particles in transport become more numerous or closely spaced and interact to reduce the effectiveness of the ambient water to move them.Field observations over a 5-year period are reported in which individual rocks were painted for identification and placed at various spacings on the bed of ephemeral stream in New Mexico, to study the effect of storm flows on rock movement. The data on about 14,000 rocks so observed show the effect of variable spacing which is quantitatively as well as qualitatively comparable to the spacing effect on small glass beads in a flume. Dunes and gravel bars may be considered kinematic waves caused by particle interaction, and certain of their properties can be related to the characteristics of the flux-concentration curve.

Field Assessment of Acoustic-Doppler Based Discharge Measurements

USGS Publications Warehouse

Mueller, D.S.; ,

2002-01-01

The use of equipment based on the Doppler principle for measuring water velocity and computing discharge is common within the U.S. Geological Survey (USGS). The instruments and software have changed appreciably during the last 5 years; therefore, the USGS has begun a field validation of the instruments currently (2002) available for making discharge measurements from a moving boat in streams of various sizes. Instruments manufactured by SonTek/YSI2 and RD Instruments, Inc. were used to collect discharge data at five different sites. One or more traditional discharge measurements were made by the use of a Price AA current meter and standard USGS procedures with the acoustic instruments at each site during data collection. The discharges measured with the acoustic instruments were compared with the discharges measured with Price AA meters and the current USGS stage-discharge rating for each site. The mean discharges measured by each acoustic instrument were within 5 percent of the Price AA-based measurement and (or) discharge from the stage-discharge rating. Additional analysis of the data collected indicates that the coefficient of variation of the discharge measurements consistently was less for the RD Instruments, Inc. Rio Grandes than it was for the SonTek/YSI RiverSurveyors. The bottom-tracking referenced measurement had a lower coefficient of variation than the differentially corrected global positioning system referenced measurements. It was observed that the higher frequency RiverSurveyors measured a moving bed more often than the lower frequency Rio Grandes. The detection of a moving bed caused RiverSurveyors to be consistently biased low when referenced to bottom tracking. Differentially corrected global positioning system data may be used to remove the bias observed in the bottom-tracking referenced measurements.

Hypo-Fractionated Conformal Radiation Therapy to the Tumor Bed after Segmental Mastectomy

DTIC Science & Technology

2007-07-01

reatment (17). Prone positioning of the patient rapidly •-merged as the best technique, because it minimizes move- neni of the target breast tissue...treatment ohase and 46 completed treatment. Three patients were lost to follow-up before initiating any treat- neni . and 1 patient discontinued treatment...Dossibility of completing the course of postsegmental nasiectomv radiotherapy (RT) in a smaller number of treat- nenis within a shorter Deriod is very

Li/sub 2/O microsphere fabrication. Monthly letter progress report No. 1 for the period ending May 31, 1977

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schluderberg, D C

1977-06-01

The purpose of this task is to establish process parameters for the fabrication of lithium oxide (Li/sub 2/O) microspheres having properties which as closely as possible approximate those required for the design characteristics of the University of Wisconsin design for a TOKAMAK-type fusion reactor utilizing the moving bed of Li/sub 2/O microspheres as both reactor coolant and tritium breeder.

Bed-Deformation Experiments Beneath a Temperate Glacier

NASA Astrophysics Data System (ADS)

Iverson, N. R.; Hooyer, T. S.; Fischer, U. H.; Cohen, D.; Jackson, M.; Moore, P. L.; Lappegard, G.; Kohler, J.

2002-12-01

Fast flow of glaciers and genesis of glacial landforms are commonly attributed to shear deformation of subglacial sediment. Although models of this process abound, data gathered subglacially on the kinematics and mechanics of such deformation are difficult to interpret. Major difficulties stem from the necessity of either measuring deformation near glacier margins, where conditions may be abnormal, or at the bottoms of boreholes, where the scope of instrumentation is limited, drilling disturbs sediment, and local boundary conditions are poorly known. A different approach is possible at the Svartisen Subglacial Laboratory, where tunnels melted in the ice provide temporary human access to the bed of Engabreen, a temperate outlet glacier of the Svartisen Ice Cap in Norway. A trough (2 m x 1.5 m x 0.5 m deep) was blasted in the rock bed, where the glacier is 220 m thick and sliding at 0.1-0.2 m/d. During two spring field seasons, this trough was filled with 2.5 tons of simulated till. Instruments in the till recorded shear (tiltmeters), volume change, total normal stress, and pore-water pressure as ice moved across the till surface. Pore pressure was brought to near the total normal stress by feeding water to the base of the till with a high-pressure pump, operated in a rock tunnel 4 m below the bed surface. Results illustrate some fundamental aspects of bed deformation. Permanent shear deformation requires low effective normal stress and hence high pore-water pressure, owing to the frictional nature of till. Shear strain generally increases upward in the bed toward the glacier sole, consistent with previous measurements beneath thinner ice at glacier margins. At low effective normal stresses, ice sometimes decouples from underlying till. Overall, bed deformation accounts for 10-35 % of basal motion, although this range excludes shear in the uppermost 0.05 m of till where shear was not measured. Pump tests with durations ranging from seconds to hours highlight the need to consider both elastic and permanent strain in evaluating tiltmeter records of bed kinematics.

Magnetic fabric of sheared till: A strain indicator for evaluating the bed deformation model of glacier flow

USGS Publications Warehouse

Hooyer, T.S.; Iverson, N.R.; Lagroix, F.; Thomason, J.F.

2008-01-01

Wet-based portions of ice sheets may move primarily by shearing their till beds, resting in high sediment fluxes and the development of subglacial landforms. This model of glacier movement, which requires high bed shear strains, can be tested using till microstructural characteristics that evolve during till deformation. Here we examine the development of magnetic fabric using a ring shear device to defom two Wisconsin-age basal tills to shear strains as high as 70. Hysteresis experiments and the dependence of magnetic susceptibility of these tills on temperature demonstrate that anisotropy of magnetic susceptibility (AMS) develops during shear due to the rotation of primarily magnetite particles that are silt sized or smaller. At moderate shear strains (???6-25), principal axes of maximum magnetic susceptibility develop a strong fabric (S1 eignevalues of 0.83-0.96), without further strengthening at higher strains, During deformation, directions of maximum susceptibility cluster strongly in the direction of shear and plunge 'up-glacier,' consistent with the behavior of pebbles and sand particles studied in earlier experiments. In contrast, the magnitude of AMS does not vary systematically with strain and is small relative to its variability among samples; this is because most magnetite grains are contained as inclusions in larger particles and hence do not align during shear. Although processes other than pervasive bed deformation may result in strong flow parallel fabrics, AMS fabrics provide a rapid and objective means of identifying basal tills that have not been sheared sufficiently to be compatible with the bed deformation model. Copyright 2008 by the American Geophysical Union.

Low-Impact Flooring: Does It Reduce Fall-Related Injuries?

PubMed

Hanger, H Carl

2017-07-01

To compare fall rates and injuries from falls on low-impact flooring (LIF) compared with a standard vinyl flooring. Prospective, observational, nonrandomized controlled study. Subacute Older Persons Health ward (N = 20 beds). Older inpatients. Three different types of LIF. All falls in the ward were prospectively monitored using incident reporting, noting location and consequences of each fall. Fall rates (per 1000 bed days) and injuries, were compared between bedroom falls on LIF against those occurring on standard vinyl flooring (controls). Over 31 months, there were 278 bedroom falls (from 178 fallers). The bedroom fall rate (falls per 1000 bed days occupied) did not differ between the LIF and control groups (median 15 [IQR 8-18] versus 17 [IQR 9-23], respectively; P = .47). However, fall-related injuries were significantly less frequent when they occurred on LIFs (22% of falls versus 34% of falls on control flooring; P = .02). Fractures occurred in 0.7% of falls in the LIF cohort versus 2.3% in the control cohort. Rolling resistance when moving heavier equipment, such as beds or hoists, was an issue for staff on LIF. LIF significantly reduced fall-related injuries compared with a standard vinyl flooring, whereas they did not alter the overall risk of falling. Copyright © 2017 AMDA – The Society for Post-Acute and Long-Term Care Medicine. Published by Elsevier Inc. All rights reserved.

Streamflow record extension using power transformations and application to sediment transport

NASA Astrophysics Data System (ADS)

Moog, Douglas B.; Whiting, Peter J.; Thomas, Robert B.

1999-01-01

To obtain a representative set of flow rates for a stream, it is often desirable to fill in missing data or extend measurements to a longer time period by correlation to a nearby gage with a longer record. Linear least squares regression of the logarithms of the flows is a traditional and still common technique. However, its purpose is to generate optimal estimates of each day's discharge, rather than the population of discharges, for which it tends to underestimate variance. Maintenance-of-variance-extension (MOVE) equations [Hirsch, 1982] were developed to correct this bias. This study replaces the logarithmic transformation by the more general Box-Cox scaled power transformation, generating a more linear, constant-variance relationship for the MOVE extension. Combining the Box-Cox transformation with the MOVE extension is shown to improve accuracy in estimating order statistics of flow rate, particularly for the nonextreme discharges which generally govern cumulative transport over time. This advantage is illustrated by prediction of cumulative fractions of total bed load transport.

Preliminary evaluation of ground-water contamination by coal-tar derivatives, St. Louis Park area, Minnesota

USGS Publications Warehouse

Hult, Marc F.; Schoenberg, Michael E.

1984-01-01

Drift materials on and south of the site have been contaminated by surface spills and by infiltration of contaminated process water. Near the contamination source, a hydrocarbon fluid phase is moving vertically downward relative to movement of the aqueous phase. Fluid pumped from an observation well in this area contained 6,000 milligrams per liter total organic carbon. Dissolved coal-tar constituents in the drift and the uppermost bedrock unit over most of the area, the Platteville aquifer, have moved at least 4,000 feet downgradient to a drift-filled bedrock valley. At the valley, it seems that the Platteville aquifer and the Glenwood confining bed have been removed by erosion and that contaminants with a concentration of approximately 2 milligrams per liter dissolved organic carbon are entering the underlying St. Peter aquifer. Chemical analyses of fluid pumped from observation wells suggest that soluble, low-molecular-weight compounds are moving preferentially through the drift and the Platteville aquifer.

Factors controlling the size and shape of stream channels in coarse noncohesive sands

USGS Publications Warehouse

Wolman, M. Gordon; Brush, Lucien M.

1961-01-01

The size and shape of equilibrium channels in uniform, noncohesive sands, 0.67 mm and 2.0 mm in diameter, were studied experimentally in a laboratory flume 52 feet long in which discharge, slope, sediment load, and bed and bank material could be varied independently. For each run a straight trapezoidal channel was molded in the sand and the flume set at a predetermined slope. Introduction of the discharge was accompanied by widening and aggradation until a stable channel was established. By definition a stable equilibrium existed when channel width, water surface slope, and rate of transport became constant. The duration of individual runs ranged from 2 to 52 hours depending upon the time required for establishing equilibrium. Stability of the banks determined channel shape. In the 2.0 mm sand at a given slope and discharge, only one depth was stable. At this depth the flow was just competent to move particles along the bed of the channel. An increase in discharge produced a wider channel of the same depth and thus transport per unit width remained at a minimum. Channels in the 0.67 mm sand were somewhat more stable and permitted a 1.5 fold increase in depth above that required to start movement of the bed material. An increased transport was associated with the increase in depth. The rate of transport is adequately described in terms of the total shear or in terms of the difference between the total shear and the critical shear required to begin movement. In these experiments the finer, or 0.67 mm, sand, began to move along the bed of the channel at a constant shear stress. Incipient movement of the coarser, or 2.0 mm, sand, varied with the shear stress as well as the mean velocity. At the initiation of movement a lower shear was associated with a higher velocity and vice versa. Anabranches of braided rivers and some natural river channels formed in relatively noncohesive materials resemble the essential characteristics of the flume channels. For a given slope and size of bed material the discharge per unit width in the laboratory channels was similar to that computed for anabranches and river channels measured in the field. Unlike most natural channels, despite impressive bank erosion, the channels in the laboratory only meandered at supercritical flows associated with very steep slopes. These conditions involving shallow depths, high velocity, and steep slopes are uncommon in most natural rivers.

METHOD OF CENTRIFUGE OPERATION

DOEpatents

Cohen, K.

1960-05-10

A method of isotope separation is described in which two streams are flowed axially of, and countercurrently through, a cylindrical centrifuge bowl. Under the influence of a centrifugal field, the light fraction is concentrated in a stream flowing through the central portion of the bowl, whereas the heavy fraction is concentrated in a stream at the periphery thereof.

User's guide to the SEPHIS computer code for calculating the Thorex solvent extraction system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, S.B.; Rainey, R.H.

1979-05-01

The SEPHIS computer program was developed to simulate the countercurrent solvent extraction process. The code has now been adapted to model the Acid Thorex flow sheet. This report represents a practical user's guide to SEPHIS - Thorex containing a program description, user information, program listing, and sample input and output.

A "Greenhouse Gas" Experiment for the Undergraduate Laboratory

ERIC Educational Resources Information Center

Gomez, Elaine; Paul, Melissa; Como, Charles; Barat, Robert

2014-01-01

This experiment and analysis offer an effective experience in greenhouse gas reduction. Ammoniated water is flowed counter-current to a simulated flue gas of air and CO2 in a packed column. The gaseous CO2 concentrations are measured with an on-line, non- dispersive, infrared analyzer. Column operating parameters include total gas flux, dissolved…

Isolation of two new prenylated flavonoids from Sinopodophyllum emodi fruit by silica gel column and high-speed counter-current chromatography.

PubMed

Sun, Yanjun; Sun, Yinshi; Chen, Hui; Hao, Zhiyou; Wang, Junmin; Guan, Yanbin; Zhang, Yanli; Feng, Weisheng; Zheng, Xiaoke

2014-10-15

Two new prenylated flavonoids, sinoflavonoids A-B, were isolated from the dried fruits of Sinopodophyllum emodi by silica gel column chromatography (SGCC) and high-speed counter-current chromatography (HSCCC). The 95% ethanol extract was partitioned with petroleum ether, dichloromethane, ethyl acetate, and n-butanol in water, respectively. The ethyl acetate fraction was pre-separated by SGCC with a petroleum ether-acetone gradient. The eluates containing target compounds were further separated by HSCCC with n-hexane-ethyl acetate-methanol-water (4:6:4:4, v/v). Finally, 17.3mg of sinoflavonoid A and 25.9mg of sinoflavonoid B were obtained from 100mg of the pretreated concentrate. The purities of sinoflavonoid A and sinoflavonoid B were 98.47% and 99.38%, respectively, as determined by HPLC. Their structures were elucidated on the basis of spectroscopic evidences (HR-ESI-MS, (1)H-NMR, (13)C-NMR, HSQC, HMBC). The separation procedures proved to be efficient, especially for trace prenylated flavonoids. Copyright © 2014 Elsevier B.V. All rights reserved.

Isolation and purification of prenylated phenolics from Amorpha fruticosa by high-speed counter-current chromatography.

PubMed

Chen, Chu; Wu, Yan; Chen, Yang; Du, Leilei

2015-08-01

Prenylated phenolics such as amorfrutins are recently identified potent anti-inflammatory and antidiabetic natural products. In this work, high-speed counter-current chromatography was investigated for the isolation and purification of prenylated phenolics from the fruits of Amorpha fruticosa by using a two-phase solvent system composed of n-hexane/ethanol/water (5:4:1, v/v). As a result, 14.2 mg of 5,7-dihydroxy-8-geranylflavanone, 10.7 mg of amorfrutin A and 17.4 mg of amorfrutin B were obtained from 200 mg of n-hexane-soluble crude extract in one step within 250 min. The purities of 5,7-dihydroxy-8-geranylflavanone, amorfrutins A and B were 95.2, 96.7 and 97.1%, respectively, as determined by ultra high performance liquid chromatography. The structural identification was performed by mass spectrometry and (1) H and (13) C NMR spectroscopy. The results indicated that the established method is an efficient and convenient way to purified prenylated phenolics from A. fruticosa extract. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Simultaneous isolation and purification of gallic acid and brevifolincarboxylic acid from Polygonum capitatum by high-speed counter-current chromatography].

PubMed

Chen, Xinxia; Zhang, Liyan; Wan, Jinzhi; Liang, Bin; Xie, Yu

2010-08-01

To isolate and purify gallic acid and brevifolincarboxylic acid simultaneously by high-speed counter-current chromatography (HSCCC) from a crude extract of Polygonum capitatum. The biphasic solvent system composed of ethyl acetate-n-butanol-0.44% acetic acid (3:1:5) was used at a flow rate of 2.0 mL x min(-1), while the aqueous phase was selected as the mobile phase and the apparatus was rotated at 860 r x min(-1). The effluent was detected at 272 nm. 51.5 mg of gallic acid and 5.9 mg of brevifolincarboxylic acid were separated from 1.07 g of the crude extract with the purities of 99.7% and 97.5%, respectively, while brevifolincarboxylic acid was obtained firstly from the genus Polygonum. The structures of the compounds were identified by ultraviolet spectrometry (UV), infra-red spectrometry (IR), liquid chromatography/mass spectrometry (LC/MS), time-of-flight mass spectrometry( TOF-MS), 1H-nuclear magnetic resonance (NMR) and 13C-NMR. This method is feasible and rapid for isolation and purification of gallice acid and brevifolincarboxylil acid.

Preparative isolation and purification of senkyunolide-I, senkyunolide-H and ferulic acid from Rhizoma Chuanxiong using counter-current chromatography.

PubMed

Wei, Yun; Hu, Jia; Li, Hao; Liu, Jiangang

2011-12-01

Three active compounds, senkyunolide-I, senkyunolide-H and ferulic acid (FA), were successfully isolated and purified from the extracts of Rhizoma Chuanxiong by counter-current chromatography (CCC). Based on the principle of the partition coefficient values (k) for target compounds and the separation factor (α) between target compounds, the two-phase solvent system that contains n-hexane-ethyl acetate-methanol-water at an optimized volume ratio of 3:7:4:6 v/v was selected for the CCC separation, and the lower phase was employed as the mobile phase in the head-to-tail elution mode. In a single run, 400 mg of the crude extract yielded pure senkyunolide-I (6.4 mg), senkyunolide-H (1.7 mg) and FA (4.4 mg) with the purities of 98, 93 and 99%, respectively. The CCC fractions were analyzed by high-performance liquid chromatography, and the structures of the three active compounds were identified by MS and (1)H NMR. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Separation of amaranthine-type betacyanins by ion-pair high-speed countercurrent chromatography.

PubMed

Jerz, Gerold; Gebers, Nadine; Szot, Dominika; Szaleniec, Maciej; Winterhalter, Peter; Wybraniec, Slawomir

2014-05-30

Betacyanins, red-violet plant pigments, were fractionated by ion-pair high-speed countercurrent chromatography (IP-HSCCC) from leaves extract of Iresine lindenii Van Houtte, an ornamental plant of the family Amaranthaceae. An HSCCC solvent system consisting of TBME-1-BuOH-ACN-H2O (1:3:1:5, v/v/v/v) was applied using ion-pair forming heptafluorobutyric acid (HFBA). Significantly different elution profiles of betacyanin diastereomeric pairs (derivatives based on betanidin and isobetanidin) observed in the HSCCC in comparison to HPLC systems indicate a complementarity of both techniques' fractionation capabilities. The numerous diastereomeric pairs can be selectively separated from each other using the HSCCC system simplifying the pigment purification process. Apart from the three well known highly abundant pigments (amaranthine, betanin and iresinin I) together with their isoforms, three new acylated (feruloylated and sinapoylated) betacyanins as well as known pigment hylocerenin (previously isolated from cacti fruits) were characterized in the plant for the first time and they are new for the whole Amaranthaceae family. Copyright © 2014 Elsevier B.V. All rights reserved.

Topsy-turvy: Turning the counter-current heat exchange of leatherback turtles upside down

USGS Publications Warehouse

Davenport, John; Jones, T. Todd; Work, Thierry M.; Balazs, George H.

2015-01-01

Counter-current heat exchangers associated with appendages of endotherms feature bundles of closely applied arteriovenous vessels. The accepted paradigm is that heat from warm arterial blood travelling into the appendage crosses into cool venous blood returning to the body. High core temperature is maintained, but the appendage functions at low temperature. Leatherback turtles have elevated core temperatures in cold seawater and arteriovenous plexuses at the roots of all four limbs. We demonstrate that plexuses of the hindlimbs are situated wholly within the hip musculature, and that, at the distal ends of the plexuses, most blood vessels supply or drain the hip muscles, with little distal vascular supply to, or drainage from the limb blades. Venous blood entering a plexus will therefore be drained from active locomotory muscles that are overlaid by thick blubber when the adults are foraging in cold temperate waters. Plexuses maintain high limb muscle temperature and avoid excessive loss of heat to the core, the reverse of the accepted paradigm. Plexuses protect the core from overheating generated by muscular thermogenesis during nesting.

Energy-efficient membrane separations in the sweetener industry. Final report for Phase I

DOE Office of Scientific and Technical Information (OSTI.GOV)

Babcock, W.C.

1984-02-14

The objective of the program is to investigate the use of membrane processes as energy-efficient alternatives to conventional separation processes in current use in the corn sweetener industry. Two applications of membranes were studied during the program: (1) the concentration of corn steep water by reverse osmosis; and (2) the concentration of dilute wastes called sweetwater with a combination of reverse osmosis and a process known as countercurrent reverse osmosis. Laboratory experiments were conducted for both applications, and the results were used to conduct technical and economic analyses of the process. It was determined that the concentration of steep watermore » by reverse osmosis plus triple-effect evaporation offers savings of a factor of 2.5 in capital costs and a factor of 4.5 in operating costs over currently used triple-effect evaporation. In the concentration of sweetwater by reverse osmosis and countercurrent reverse osmosis, capital costs would be about the same as those for triple-effect evaporation, but operating costs would be only about one-half those of triple-effect evaporation.« less

Topsy-turvy: turning the counter-current heat exchange of leatherback turtles upside down.

PubMed

Davenport, John; Jones, T Todd; Work, Thierry M; Balazs, George H

2015-10-01

Counter-current heat exchangers associated with appendages of endotherms feature bundles of closely applied arteriovenous vessels. The accepted paradigm is that heat from warm arterial blood travelling into the appendage crosses into cool venous blood returning to the body. High core temperature is maintained, but the appendage functions at low temperature. Leatherback turtles have elevated core temperatures in cold seawater and arteriovenous plexuses at the roots of all four limbs. We demonstrate that plexuses of the hindlimbs are situated wholly within the hip musculature, and that, at the distal ends of the plexuses, most blood vessels supply or drain the hip muscles, with little distal vascular supply to, or drainage from the limb blades. Venous blood entering a plexus will therefore be drained from active locomotory muscles that are overlaid by thick blubber when the adults are foraging in cold temperate waters. Plexuses maintain high limb muscle temperature and avoid excessive loss of heat to the core, the reverse of the accepted paradigm. Plexuses protect the core from overheating generated by muscular thermogenesis during nesting. © 2015 The Author(s).

The impact of capillary backpressure on spontaneous counter-current imbibition in porous media

NASA Astrophysics Data System (ADS)

Foley, Amir Y.; Nooruddin, Hasan A.; Blunt, Martin J.

2017-09-01

We investigate the impact of capillary backpressure on spontaneous counter-current imbibition. For such displacements in strongly water-wet systems, the non-wetting phase is forced out through the inlet boundary as the wetting phase imbibes into the rock, creating a finite capillary backpressure. Under the assumption that capillary backpressure depends on the water saturation applied at the inlet boundary of the porous medium, its impact is determined using the continuum modelling approach by varying the imposed inlet saturation in the analytical solution. We present analytical solutions for the one-dimensional incompressible horizontal displacement of a non-wetting phase by a wetting phase in a porous medium. There exists an inlet saturation value above which any change in capillary backpressure has a negligible impact on the solutions. Above this threshold value, imbibition rates and front positions are largely invariant. A method for identifying this inlet saturation is proposed using an analytical procedure and we explore how varying multiphase flow properties affects the analytical solutions and this threshold saturation. We show the value of this analytical approach through the analysis of previously published experimental data.

Steady state preparative multiple dual mode counter-current chromatography: Productivity and selectivity. Theory and experimental verification.

PubMed

Kostanyan, Artak E; Erastov, Andrey A

2015-08-07

In the steady state (SS) multiple dual mode (MDM) counter-current chromatography (CCC), at the beginning of the first step of every cycle the sample dissolved in one of the phases is continuously fed into a CCC device over a constant time, not exceeding the run time of the first step. After a certain number of cycles, the steady state regime is achieved, where concentrations vary over time during each cycle, however, the concentration profiles of solutes eluted with both phases remain constant in all subsequent cycles. The objective of this work was to develop analytical expressions to describe the SS MDM CCC separation processes, which can be helpful to simulate and design these processes and select a suitable compromise between the productivity and the selectivity in the preparative and production CCC separations. Experiments carried out using model mixtures of compounds from the GUESSmix with solvent system hexane/ethyl acetate/methanol/water demonstrated a reasonable agreement between the predictions of the theory and the experimental results. Copyright © 2015 Elsevier B.V. All rights reserved.

Preparative separation of cacao bean procyanidins by high-speed counter-current chromatography.

PubMed

Li, Lingxi; Zhang, Shuting; Cui, Yan; Li, Yuanyuan; Luo, Lanxin; Zhou, Peiyu; Sun, Baoshan

2016-11-15

In this work, an efficient method for preparative separation of procyanidins from raw cacao bean extract by high-speed counter-current chromatography (HSCCC) was developed. Under the optimized solvent system of n-hexane-ethyl acetate-water (1:50:50, v/v/v) with a combination of head-tail and tail-head elution modes, various procyanidins fractions with different polymerization degrees were successfully separated. UPLC, QTOF-MS and 1 H NMR analysis verified that these fractions contained monomer up to pentamer respectively. Dimeric procyanidin B2 (purity>86%) could be isolated by HSCCC in a single run. Other individual procyanidins in these fractions could be further isolated and purified by preparative HPLC. The developed HSCCC together with preparative HPLC techniques appeared to be a useful tool for large preparation of different procyanidins from cacao beans. Furthermore, by antioxidant activity assays, it was proved that both fractions and individual procyanidins possessed greater antioxidant activities compared to standard trolox. The antioxidant activities of procyanidins increase as the increase of their polymerization degree. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparative Isolation and Purification of Flavone C-Glycosides from the Leaves of Ficus microcarpa L. f by Medium-Pressure Liquid Chromatography, High-Speed Countercurrent Chromatography, and Preparative Liquid Chromatography

PubMed Central

Wang, Xiaohong; Liang, Yong; Zhu, Licai; Xie, Huichun; Li, Hang; He, Junting; Pan, Man; Zhang, Tianyou; Ito, Yoichiro

2009-01-01

Combined with medium-pressure liquid chromatography (MPLC) and preparative high-performance liquid chromatography (perp-HPLC), high-speed countercurrent chromatography (HSCCC) was applied for separation and purification of flavone C-glycosides from the crude extract of leaves of Ficus microcarpae L. f. HSCCC separation was performed on a two-phase solvent system composed of methyl tert- butyl ether - ethyl acetate – 1-butanol – acetonitrile – 0.1% aqueous trifluoroacetic acid at a volume ratio of 1:3:1:1:5. Partially resolved peak fractions from HSCCC separation were further purified by preparative HPLC. Four well-separated compounds were obtained and their purities were determined by HPLC. The purities of these peaks were 97.28%, 97.20%, 92.23%, and 98.40%.. These peaks were characterized by ESI-MSn. According to the reference, they were identified as orientin (peak I), isovitexin-3″-O-glucopyranoside (peak II), isovitexin (peak III), and vitexin (peak IV), yielded 1.2 mg, 4.5 mg, 3.3 mg, and 1.8 mg, respectively. PMID:20190866

A laplace transform-based technique for solving multiscale and multidomain problems: Application to a countercurrent hemodialyzer model.

PubMed

Simon, Laurent

2017-08-01

An integral-based method was employed to evaluate the behavior of a countercurrent hemodialyzer model. Solute transfer from the blood into the dialysate was described by writing mass balance equations over a section of the device. The approach provided Laplace transform concentration profiles on both sides of the membrane. Applications of the final value theorem led to the development of the effective time constants and steady-state concentrations in the exit streams. Transient responses were derived by a numerical inversion algorithm. Simulations show that the period elapsed, before reaching equilibrium in the effluents, decreased when the blood flow rate increased from 0.25 to 0.30 ml/s. The performance index decreased from 0.80 to 0.71 when the blood-to-dialysate flow ratio increased by 20% and increased from 0.80 to 0.85 when this fraction was reduced by 17%. The analytical solution predicted methadone removal in patients undergoing dialysis. Clinicians can use these findings to predict the time required to achieve a target extraction ratio. Copyright © 2017 Elsevier Ltd. All rights reserved.

Countercurrent extraction of soluble sugars from almond hulls and assessment of the bioenergy potential.

PubMed

Holtman, Kevin M; Offeman, Richard D; Franqui-Villanueva, Diana; Bayati, Andre K; Orts, William J

2015-03-11

Almond hulls contain considerable proportions (37% by dry weight) of water-soluble, fermentable sugars (sucrose, glucose, and fructose), which can be extracted for industrial purposes. The maximum optimal solids loading was determined to be 20% for sugar extraction, and the addition of 0.5% (w/v) pectinase aided in maintaining a sufficient free water volume for sugar recovery. A laboratory countercurrent extraction experiment utilizing a 1 h steep followed by three extraction (wash) stages produced a high-concentration (131 g/L fermentable sugar) syrup. Overall, sugar recovery efficiency was 88%. The inner stage washing efficiencies were compatible with solution equilibrium calculations, indicating that efficiency was high. The concentrated sugar syrup was fermented to ethanol at high efficiency (86% conversion), and ethanol concentrations in the broth were 7.4% (v/v). Thin stillage contained 233 g SCOD/L, which was converted to biomethane at an efficiency of 90% with a biomethane potential of 297 mL/g SCODdestroyed. Overall, results suggested that a minima of 49 gal (185 L) ethanol and 75 m(3) methane/t hulls (dry whole hull basis) are achievable.

Preparative separation of grape skin polyphenols by high-speed counter-current chromatography.

PubMed

Luo, Lanxin; Cui, Yan; Zhang, Shuting; Li, Lingxi; Li, Yuanyuan; Zhou, Peiyu; Sun, Baoshan

2016-12-01

To develop an efficient method for large preparation of various individual polyphenols from white grape skins (Fernão Pires; Vitis vinifera) by preparative high-speed counter-current chromatography (HSCCC) and preparative-HPLC, an optimized preparative HSCCC condition with two-phase solvent system composed of Hex-EtOAc-H2O (1:50:50, v/v) was used to separate grape skin polyphenols into various fractions. Both the tail-head and head-tail elution modes were used with a flow rate of 3.0ml/min and a rotary speed of 950rpm. Afterwards, a preparative-HPLC separation was applied to isolate individual polyphenols in each of the fractions from HSCCC. Total of 7 fractions (Fraction A to G) were obtained from grape skin extract by HSCCC. After preparative-HPLC isolation, fifteen individual compounds were obtained, most of which presented high yields and purity (all over 90%). The HSCCC method followed with preparative-HPLC appeared to be convenient and economical, constituting an efficient strategy for the isolation of grape skin polyphenols. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preparative enantioseparation of propafenone by counter-current chromatography using di-n-butyl L-tartrate combined with boric acid as the chiral selector.

PubMed

Tong, Shengqiang; Shen, Mangmang; Zheng, Ye; Chu, Chu; Li, Xing-Nuo; Yan, Jizhong

2013-09-01

This paper extends the research of the utilization of borate coordination complexes in chiral separation by counter-current chromatography (CCC). Racemic propafenone was successfully enantioseparated by CCC with di-n-butyl l-tartrate combined with boric acid as the chiral selector. The two-phase solvent system was composed of chloroform/ 0.05 mol/L acetate buffer pH 3.4 containing 0.10 mol/L boric acid (1:1, v/v), in which 0.10 mol/L di-n-butyl l-tartrate was added in the organic phase. The influence of factors in the enantioseparation of propafenone were investigated and optimized. A total of 92 mg of racemic propafenone was completely enantioseparated using high-speed CCC in a single run, yielding 40-42 mg of (R)- and (S)-propafenone enantiomers with an HPLC purity over 90-95%. The recovery for propafenone enantiomers from fractions of CCC was in the range of 85-90%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Countercurrent flow limited (CCFL) heat flux in the high flux isotope reactor (HFIR) fuel element

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruggles, A.E.

1990-10-12

The countercurrent flow (CCF) performance in the fuel element region of the HFIR is examined experimentally and theoretically. The fuel element consists of two concentric annuli filled with aluminum clad fuel plates of 1.27 mm thickness separated by 1.27 mm flow channels. The plates are curved as they go radially outward to accomplish constant flow channel width and constant metal-to-coolant ratio. A full-scale HFIR fuel element mock-up is studied in an adiabatic air-water CCF experiment. A review of CCF models for narrow channels is presented along with the treatment of CCFs in system of parallel channels. The experimental results aremore » related to the existing models and a mechanistic model for the annular'' CCF in a narrow channel is developed that captures the data trends well. The results of the experiment are used to calculate the CCFL heat flux of the HFIR fuel assembly. It was determined that the HFIR fuel assembly can reject 0.62 Mw of thermal power in the CCFL situation. 31 refs., 17 figs.« less

Seabed Motion During Sediment Density Flows as Recorded by Displaced Man-Made Motion-Recording Boulders and a Heavy Instrument Platform

NASA Astrophysics Data System (ADS)

Gwiazda, R.; Paull, C. K.; Kieft, B.; Bird, L.; Klimov, D.; Herlien, R.; Sherman, A.; McCann, M. P.; Sumner, E.; Talling, P.; Xu, J.; Parsons, D. R.; Maier, K. L.; Barry, J.

2017-12-01

Over a period of 18 months the Coordinated Canyon Experiment documented the passage of at least 15 sediment density flows in Monterey Canyon, offshore California, with an array of moorings and sensors placed from 200 m to 1,850 m water depths. Free-standing `smart' boulders (Benthic Event Detectors, BED) and a 1,000 Kg tripod with an Acoustic Monitoring Transponder (AMT) and a BED attached to it were deployed in the upper canyon to detect seabed motions during sediment density flows. BEDs consist of spheres made of a combination of metal, plastic and syntactic foam ballasted to 2.1 g/cm3 density, containing accelerometers along three orthogonal axes, a time recorder, and a pressure sensor inside a pressure case rated to 500 m water depth. Acceleration of ≥ 0.008 G triggers data collection at a recording rate of 50 Hz until motion stops. Built-in acoustic beacons and modems allow for BEDs to be relocated, and data to be downloaded, even when BEDs are buried in sediment to depths of >1 m. Over the course of the study, depth changes and velocities of 24 BED movements during 9 events were recorded. BEDs moved at the velocity of the propagation of the flows down canyon, as documented by the time of arrival of the flow at successive sensors, but sometimes travelled at lower speeds. Seven movements of the AMT tripod were also recorded. In the largest of these, the heavy AMT tripod was transported over a distance of 4.1 Km. For at least four of these seven motions the AMT temperature record indicates that the movements were initiated while the tripod was buried. In one particular event simultaneous movements of five BEDs over a 100 m depth range indicate that the entire seabed was in motion at the same time over a canyon distance of 3.5 Km. Reconstructions of instrument motions in this event from their internally recorded acceleration data show that the AMT displacement was at the front of the event and had no rotational component. In contrast, free standing BEDs at the same depth advanced through a combination of translational and rotational motion. These data are consistent with sediment density flows involving fluidization and motion of a segment of the seafloor over long distances.

DISCHARGE VALVE FOR GRANULAR MATERIAL

DOEpatents

Stoughton, L.D.; Robinson, S.T.

1962-05-15

A gravity-red dispenser or valve is designed for discharging the fueled spherical elements used in a pebble bed reactor. The dispenser consists of an axially movable tube terminating under a hood having side walls with openings. When the tube is moved so that its top edge is above the tops of the side openings the elements will not flow. As the tube is moved downwardly, the elements flow into the hood through the side openings and over the top edge into the tube at an increasing rate as the tube is lowered further. The tube is spaced at all times from the hood and side walls a distance greater than the diameter of the largest element to prevent damaging of the elements when the dispenser is closed to flow. (AEC)

Preparation of Sesquiterpenoids from Tussilago farfara L. by High-speed Counter-current Chromatography

PubMed Central

Cao, Kun; Xu, Yi; Zhao, Tian-Ming; Zhang, Qing

2016-01-01

Background: Sesquiterpenoids, such as tussilagone, has effects of raising blood pressure, antiplatelet aggregation, and anti-inflammation activities, which is regarded as index compound for quality control of Tussilago farfara L. Objective: This study was aimed to obtain an effective method for fast isolation of sesquiterpenoids from T. farfara L. by high-speed counter-current chromatography (HSCCC). Materials and Methods: A solvent optimization method for HSCCC was presented, i.e., the separation factors of compounds after the K values of solvent system should be investigated. Results: A ternary solvent system of n-hexane:methanol:water (5:8:2, v/v/v) was selected and applied for the HSCCC, and 56 mg of tussilagone (2) was isolated from T. farfara L., along with two other sesquiterpenoids 5.6 mg of 2,2-dimethyl-6-acetylchromanone (1) and 22 mg of 14-acetoxy-7 β-(3’-ethyl cis-crotonoyloxy)-lα-(2’-methylbutyryloxy)-notonipetranone (3) by HSCCC with high purities. Their chemical structures were elucidated by liquid chromatography-mass spectrometry and nuclear magnetic resonance experiments. Conclusion: These results offered an efficient strategy for preparation of potentially health-relevant phytochemicals from T. farfara L., which might be used for further chemical research and pharmacological studies by preparative HSCCC. SUMMARY The real separation efficiency has been verified by analytical HSCCC.A solvent optimization method for HSCCC was presented and applied to separate and prepare active compounds.A method for rapid and effective separation of target compound Tussilagone with high yield and purity from the flower buds of Tussilago farfara.Two other compounds 2,2-Dimethyl-6-acetylchromanone and 14-acetoxy-7β-(3’-ethyl cis-crotonoyloxy) -lα- (2’-methylbutyryloxy). notonipetranone hasbeen obtained with high purities from flower buds of Tussilago farfara. Abbreviations used: HSCCC: High-Speed Counter-Current Chromatography; LC-MS: Liquid Chromatograph-Mass Spectrometer; NMR: Nuclear Magnetic Resonance; TCM: Traditional Chinese Medicine; HPLC: High Performance Liquid Chromatography; ESI-MS: Electrospray Ionization Mass Spectrometry; PE: petroleum ether PMID:27867270

Heat and Momentum Transfer Studies in High Reynolds Number Wavy Films at Normal and Reduced Gravity Conditions

NASA Technical Reports Server (NTRS)

Balakotaiah, V.

1996-01-01

We examined the effect of the gas flow on the liquid film when the gas flows in the countercurrent direction in a vertical pipe at normal gravity conditions. The most dramatic effect of the simultaneous flow of gas and liquid in pipes is the greatly increased transport rates of heat, mass, and momentum. In practical situations this enhancement can be a benefit or it can result in serious operational problems. For example, gas-liquid flow always results in substantially higher pressure drop and this is usually undesirable. However, much higher heat transfer coefficients can be expected and this can obviously be of benefit for purposes of design. Unfortunately, designers know so little of the behavior of such two phase systems and as a result these advantages are not utilized. Due to the complexity of the second order boundary model as well as the fact that the pressure variation across the film is small compared to the imposed gas phase pressure, the countercurrent gas flow affect was studied for the standard boundary layer model. A different stream function that can compensate the shear stress affect was developed and this stream function also can predict periodic solutions. The discretized model equations were transformed to a traveling wave coordinate system. A stability analysis of these sets of equations showed the presence of a Hopf bifurcation for certain values of the traveling wave velocity and the shear stress. The Hopf celerity was increased due to the countercurrent shear. For low flow rate the increases of celerity are more than for the high flow rate, which was also observed in experiments. Numerical integration of a traveling wave simplification of the model also predicts the existence of chaotic large amplitude, nonperiodic waves as observed in the experiments. The film thickness was increased by the shear.

A Cultural Resource Inventory of 13 Proposed Waterfowl Ponds and a Sample of the Prairie Dog Arm, Harlan County Lake, Nebraska

DTIC Science & Technology

1988-01-01

information derived from surrounding areas, this cultural period was characterized by intensive hunting of Pleistocene megafauna augmented by some gathering...migratory patterns of the Pleistocene megafauna brought about by the Altithermal climatic shifts. Archaic period sites contain nebulous house floors...surpassed the erosional and gradient stages. In the project area streams with mature beds have low gradients and are slow moving through wide meander

The Coast Artillery Journal. Volume 77, Number 3, May-June 1934

DTIC Science & Technology

1934-06-01

from its bed. Two large holes had been b~rned in the bottom but the artificer plugged them with ~Iecesof a cork -like wood of the variety used by the...May-June By order of Captain, 29th Infantry. Adjutant . Headquarters Twenty-Ninth Infantry Office of the Regimental Commander Fort Benning, Georgia...January 24, 1934, OFFICIAL: Captain, 29th Infantry, Adjutant . FIELD ORDERS ) NO. I ) I. The regiment will move by rail pursuant to the Regimental

Study of the efficiency of moving bed biofilm reactor (MBBR) in LAS Anionic Detergent removal from hospital wastewater: determination of removing model according to response surface methodology (RSM).

PubMed

Shokoohi, Reza; Torkshavand, Zahra; Zolghadnasab, Hassan; Alikhani, Mohammad Yousef; Hemmat, Meisam Sedighi

2017-04-01

Detergents are considered one of the important pollutants in hospital wastewater. Achieving efficient and bio-friendly methods for the removal of these pollutants is considered as a concern for environmental researchers. This study aims at studying the efficiency of a moving bed biofilm reactor (MBBR) system for removing linear alkyl benzene sulfonate (LAS) from hospital wastewater with utilization of response surface methodology (RSM). The present study was carried out on a reactor with continuous hydraulic flow using media k 1 at pilot scale to remove detergent from hospital wastewater. The effect of independent variables including contact time, percentage of media filling and mixed liquor suspended solids (MLSS) concentration of 1000-3000 mg/l on the system efficiency were assessed. Methylene blue active substances (MBAS) and chemical oxygen demand (COD) 750-850 mg/l were used by closed laboratory method in order to measure the concentration of LAS. The results revealed that the removal efficiency of LAS detergent and COD using media k 1 , retention time of 24 hours, and MLSS concentration of around 3,000 mg/l were 92.3 and 95.8%, respectively. The results showed that the MBBR system as a bio-friendly compatible method has high efficiency in removing detergents from hospital wastewater and can achieve standard output effluent in acceptable time.

dsrAB-based analysis of sulphate-reducing bacteria in moving bed biofilm reactor (MBBR) wastewater treatment plants.

PubMed

Biswas, Kristi; Taylor, Michael W; Turner, Susan J

2014-08-01

Sulphate-reducing bacteria (SRB) are important members of the sulphur cycle in wastewater treatment plants (WWTPs). In this study, we investigate the diversity and activity of SRB within the developing and established biofilm of two moving bed biofilm reactor (MBBR) systems treating municipal wastewater in New Zealand. The larger of the two WWTPs (Moa Point) generates high levels of sulphide relative to the smaller Karori plant. Clone libraries of the dissimilatory (bi)sulphite reductase (dsrAB) genes and quantitative real-time PCR targeting dsrA transcripts were used to compare SRB communities between the two WWTPs. Desulfobulbus (35-53 % of total SRB sequences) and genera belonging to the family Desulfobacteraceae (27-41 %) dominated the SRB fraction of the developing biofilm on deployed plastic carriers at both sites, whereas Desulfovibrio and Desulfomicrobium were exclusively found at Moa Point. In contrast, the established biofilms from resident MBBR carriers were largely dominated by Desulfomonile tiedjei-like organisms (58-100 % of SRB sequences). The relative transcript abundance of dsrA genes (signifying active SRBs) increased with biofilm weight yet remained low overall, even in the mature biofilm stage. Our results indicate that although SRB are both present and active in the microbial community at both MBBR study sites, differences in the availability of sulphate may be contributing to the observed differences in sulphide production at these two plants.

Difficulties in maintaining long-term partial nitritation of ammonium-rich sludge digester liquids in a moving-bed biofilm reactor (MBBR).

PubMed

Fux, C; Huang, D; Monti, A; Siegrist, H

2004-01-01

Nitrogen can be eliminated effectively from sludge digester effluents by anaerobic ammonium oxidation (anammox), but 55-60% of the ammonium must first be oxidized to nitrite. Although a continuous flow stirred tank reactor (CSTR) with suspended biomass could be used, its hydraulic dilution rate is limited to 0.8-1 d(-1) (30 degrees C). Higher specific nitrite production rates can be achieved by sludge retention, as shown here for a moving-bed biofilm reactor (MBBR) with Kaldnes carriers on laboratory and pilot scales. The maximum nitrite production rate amounted to 2.7 gNO2-Nm(-2)d(-1) (3 gO2m(-3)d(-1), 30.5 degrees C), thus doubling the dilution rate compared to CSTR operation with suspended biomass for a supernatant with 700 gNH4-Nm(-3). Whenever the available alkalinity was fully consumed, an optimal amount of nitrite was produced. However, a significant amount of nitrate was produced after 11 months of operation, making the effluent unsuitable for anaerobic ammonium oxidation. Because the sludge retention time (SRT) is relatively long in biofilm systems, slow growth of nitrite oxidizers occurs. None of the selection criteria applied - a high ammonium loading rate, high free ammonia or low oxygen concentration - led to selective suppression of nitrite oxidation. A CSTR or SBR with suspended biomass is consequently recommended for full-scale operation.

Two-step nitrification in a pure moving bed biofilm reactor-membrane bioreactor for wastewater treatment: nitrifying and denitrifying microbial populations and kinetic modeling.

PubMed

Leyva-Díaz, J C; González-Martínez, A; Muñío, M M; Poyatos, J M

2015-12-01

The moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) is a novel solution to conventional activated sludge processes and membrane bioreactors. In this study, a pure MBBR-MBR was studied. The pure MBBR-MBR mainly had attached biomass. The bioreactor operated with a hydraulic retention time (HRT) of 9.5 h. The kinetic parameters for heterotrophic and autotrophic biomasses, mainly nitrite-oxidizing bacteria (NOB), were evaluated. The analysis of the bacterial community structure of the ammonium-oxidizing bacteria (AOB), NOB, and denitrifying bacteria (DeNB) from the pure MBBR-MBR was carried out by means of pyrosequencing to detect and quantify the contribution of the nitrifying and denitrifying bacteria in the total bacterial community. The relative abundance of AOB, NOB, and DeNB were 5, 1, and 3%, respectively, in the mixed liquor suspended solids (MLSS), and these percentages were 18, 5, and 2%, respectively, in the biofilm density (BD) attached to carriers. The pure MBBR-MBR had a high efficiency of total nitrogen (TN) removal of 71.81±16.04%, which could reside in the different bacterial assemblages in the fixed biofilm on the carriers. In this regard, the kinetic parameters for autotrophic biomass had values of YA=2.3465 mg O2 mg N(-1), μm, A=0.7169 h(-1), and KNH=2.0748 mg NL(-1).

Anammox moving bed biofilm reactor pilot at the 26th Ward wastewater treatment plants in Brooklyn, New York: start-up, biofilm population diversity and performance optimization.

PubMed

Mehrdad, M; Park, H; Ramalingam, K; Fillos, J; Beckmann, K; Deur, A; Chandran, K

2014-01-01

New York City Environmental Protection in conjunction with City College of New York assessed the application of the anammox process in the reject water treatment using a moving bed biofilm reactor (MBBR) located at the 26th Ward wastewater treatment plant, in Brooklyn, NY. The single-stage nitritation/anammox MBBR was seeded with activated sludge and consequently was enriched with its own 'homegrown' anammox bacteria (AMX). Objectives of this study included collection of additional process kinetic and operating data and assessment of the effect of nitrogen loading rates on process performance. The initial target total inorganic nitrogen removal of 70% was limited by the low alkalinity concentration available in the influent reject water. Higher removals were achieved after supplementing the alkalinity by adding sodium hydroxide. Throughout startup and process optimization, quantitative real-time polymerase chain reaction (qPCR) analyses were used for monitoring the relevant species enriched in the biofilm and in the suspension. Maximum nitrogen removal rate was achieved by stimulating the growth of a thick biofilm on the carriers, and controlling the concentration of dissolved oxygen in the bulk flow and the nitrogen loading rates per surface area; all three appear to have contributed in suppressing nitrite-oxidizing bacteria activity while enriching AMX density within the biofilm.

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.

Expanding AirSTAR Capability for Flight Research in an Existing Avionics Design

NASA Technical Reports Server (NTRS)

Laughter, Sean A.

2012-01-01

The NASA Airborne Subscale Transport Aircraft Research (AirSTAR) project is an Unmanned Aerial Systems (UAS) test bed for experimental flight control laws and vehicle dynamics research. During its development, the test bed has gone through a number of system permutations, each meant to add functionality to the concept of operations of the system. This enabled the build-up of not only the system itself, but also the support infrastructure and processes necessary to support flight operations. These permutations were grouped into project phases and the move from Phase-III to Phase-IV was marked by a significant increase in research capability and necessary safety systems due to the integration of an Internal Pilot into the control system chain already established for the External Pilot. The major system changes in Phase-IV operations necessitated a new safety and failsafe system to properly integrate both the Internal and External Pilots and to meet acceptable project safety margins. This work involved retrofitting an existing data system into the evolved concept of operations. Moving from the first Phase-IV aircraft to the dynamically scaled aircraft further involved restructuring the system to better guard against electromagnetic interference (EMI), and the entire avionics wiring harness was redesigned in order to facilitate better maintenance and access to onboard electronics. This retrofit and harness re-design will be explored and how it integrates with the evolved Phase-IV operations.

Membrane distillation combined with an anaerobic moving bed biofilm reactor for treating municipal wastewater.

PubMed

Kim, Hyun-Chul; Shin, Jaewon; Won, Seyeon; Lee, Jung-Yeol; Maeng, Sung Kyu; Song, Kyung Guen

2015-03-15

A fermentative strategy with an anaerobic moving bed biofilm reactor (AMBBR) was used for the treatment of domestic wastewater. The feasibility of using a membrane separation technique for post-treatment of anaerobic bio-effluent was evaluated with emphasis on employing a membrane distillation (MD). Three different hydrophobic 0.2 μm membranes made of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and polypropylene (PP) were examined in this study. The initial permeate flux of the membranes ranged from 2.5 to 6.3 L m(-2) h(-1) when treating AMBBR effluent at a temperature difference between the feed and permeate streams of 20 °C, with the permeate flux increasing in the order PP < PVDF < PTFE. The permeate flux of the PTFE membrane gradually decreased to 84% of the initial flux after the 45 h run for distillation, while a flux decline in MD with either the PVDF or PP membrane was not found under the identical distillation conditions. During long-term distillation with the PVDF membrane, total phosphorus was completely rejected and >98% rejection of dissolved organic carbon was also achieved. The characterization of wastewater effluent organic matter (EfOM) using an innovative suite of analytical tools verified that almost all of the EfOM was rejected via the PVDF MD treatment. Copyright © 2015 Elsevier Ltd. All rights reserved.