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1

Ion transport through cell membrane channels  

E-Print Network [OSTI]

We discuss various models of ion transport through cell membrane channels. Recent experimental data shows that sizes of ion channels are compared to those of ions and that only few ions may be simultaneously in any single channel. Theoretical description of ion transport in such channels should therefore take into account interactions between ions and between ions and channel proteins. This is not satisfied by macroscopic continuum models based on Poisson-Nernst-Planck equations. More realistic descriptions of ion transport are offered by microscopic Brownian and molecular dynamics. One should also take into account a dynamical character of the channel structure. This is not yet addressed in the literature

Jan Gomulkiewicz; Jacek Miekisz; Stanislaw Miekisz

2007-06-05T23:59:59.000Z

2

Ion transport membrane module and vessel system  

DOE Patents [OSTI]

An ion transport membrane system comprising (a) a pressure vessel having an interior, an exterior, an inlet, and an outlet; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region, wherein any inlet and any outlet of the pressure vessel are in flow communication with exterior regions of the membrane modules; and (c) one or more gas manifolds in flow communication with interior regions of the membrane modules and with the exterior of the pressure vessel. The ion transport membrane system may be utilized in a gas separation device to recover oxygen from an oxygen-containing gas or as an oxidation reactor to oxidize compounds in a feed gas stream by oxygen permeated through the mixed metal oxide ceramic material of the membrane modules.

Stein, VanEric Edward (Allentown, PA); Carolan, Michael Francis (Allentown, PA); Chen, Christopher M. (Allentown, PA); Armstrong, Phillip Andrew (Orefield, PA); Wahle, Harold W. (North Canton, OH); Ohrn, Theodore R. (Alliance, OH); Kneidel, Kurt E. (Alliance, OH); Rackers, Keith Gerard (Louisville, OH); Blake, James Erik (Uniontown, OH); Nataraj, Shankar (Allentown, PA); Van Doorn, Rene Hendrik Elias (Obersulm-Willsbach, DE); Wilson, Merrill Anderson (West Jordan, UT)

2012-02-14T23:59:59.000Z

3

Ion transport membrane module and vessel system  

DOE Patents [OSTI]

An ion transport membrane system comprising (a) a pressure vessel having an interior, an exterior, an inlet, and an outlet; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region, wherein any inlet and any outlet of the pressure vessel are in flow communication with exterior regions of the membrane modules; and (c) one or more gas manifolds in flow communication with interior regions of the membrane modules and with the exterior of the pressure vessel.The ion transport membrane system may be utilized in a gas separation device to recover oxygen from an oxygen-containing gas or as an oxidation reactor to oxidize compounds in a feed gas stream by oxygen permeated through the mixed metal oxide ceramic material of the membrane modules.

Stein, VanEric Edward (Allentown, PA); Carolan, Michael Francis (Allentown, PA); Chen, Christopher M. (Allentown, PA); Armstrong, Phillip Andrew (Orefield, PA); Wahle, Harold W. (North Canton, OH); Ohrn, Theodore R. (Alliance, OH); Kneidel, Kurt E. (Alliance, OH); Rackers, Keith Gerard (Louisville, OH); Blake, James Erik (Uniontown, OH); Nataraj, Shankar (Allentown, PA); van Doorn, Rene Hendrik Elias (Obersulm-Willsbach, DE); Wilson, Merrill Anderson (West Jordan, UT)

2008-02-26T23:59:59.000Z

4

Liners for ion transport membrane systems  

SciTech Connect (OSTI)

Ion transport membrane system comprising (a) a pressure vessel comprising an interior, an exterior, an inlet, an inlet conduit, an outlet, and an outlet conduit; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region, wherein the inlet and the outlet of the pressure vessel are in flow communication with exterior regions of the membrane modules; (c) a gas manifold having an interior surface wherein the gas manifold is in flow communication with the interior region of each of the planar ion transport membrane modules and with the exterior of the pressure vessel; and (d) a liner disposed within any of the inlet conduit, the outlet conduit, and the interior surface of the gas manifold.

Carolan, Michael Francis (Allentown, PA); Miller, Christopher Francis (Macungie, PA)

2010-08-10T23:59:59.000Z

5

Ion Transport Through Cell Membrane Channels Jan Gomulkiewicz1  

E-Print Network [OSTI]

1 Ion Transport Through Cell Membrane Channels Jan Gomulkiewicz1 , Jacek Mikisz2 , and Stanislaw various models of ion transport through cell membrane channels. Recent experimental data shows that sizes for the life of a cell. In particular, a fundamental phenomenon is a transport of ions through cell membranes

Miekisz, Jacek

6

Fabrication of catalyzed ion transport membrane systems  

DOE Patents [OSTI]

Process for fabricating a catalyzed ion transport membrane (ITM). In one embodiment, an uncatalyzed ITM is (a) contacted with a non-reducing gaseous stream while heating to a temperature and for a time period sufficient to provide an ITM possessing anion mobility; (b) contacted with a reducing gaseous stream for a time period sufficient to provide an ITM having anion mobility and essentially constant oxygen stoichiometry; (c) cooled while contacting the ITM with the reducing gaseous stream to provide an ITM having essentially constant oxygen stoichiometry and no anion mobility; and (d) treated by applying catalyst to at least one of (1) a porous mixed conducting multicomponent metallic oxide (MCMO) layer contiguous with a first side of a dense layer of MCMO and (2) a second side of the dense MCMO layer. In another embodiment, these steps are carried out in the alternative order of (a), (d), (b), and (c).

Carolan, Michael Francis; Kibby, Charles Leonard

2013-06-04T23:59:59.000Z

7

Feed gas contaminant removal in ion transport membrane systems  

SciTech Connect (OSTI)

An oxygen ion transport membrane process wherein a heated oxygen-containing gas having one or more contaminants is contacted with a reactive solid material to remove the one or more contaminants. The reactive solid material is provided as a deposit on a support. The one or more contaminant compounds in the heated oxygen-containing gas react with the reactive solid material. The contaminant-depleted oxygen-containing gas is contacted with a membrane, and oxygen is transported through the membrane to provide transported oxygen.

Underwood, Richard Paul (Allentown, PA); Makitka, III, Alexander (Hatfield, PA); Carolan, Michael Francis (Allentown, PA)

2012-04-03T23:59:59.000Z

8

Advances in ion transport membrane technology for Syngas production  

Science Journals Connector (OSTI)

Abstract Ceramic, ion transport membranes for the production of Syngas (ITM Syngas) produce high pressure synthesis gas in a single unit operation from low pressure air and pre-reformed natural gas. Oxygen transport through ITM Syngas membranes occurs through a series of processes, including solid phase oxygen anion diffusion through the dense membrane and surface reactions on the air and reducing sides of the membrane. This paper focuses on the effect of adding porous layers to the syngas side or both sides of the membrane to increase the available surface area for the surface reactions. The highest fluxes are achieved by increasing the surface area on both sides of the membrane, indicating that both surface reactions are a significant resistance to oxygen transport.

C.F. Miller; Jack Chen; M.F. Carolan; E.P. Foster

2014-01-01T23:59:59.000Z

9

Electrochemical control of ion transport through a mesoporous carbon membrane  

SciTech Connect (OSTI)

The transport of fluids through nanometer scale channels typically on the order of 1 -100 nm often exhibit unique properties compared to the bulk fluid. These phenomena occur because the channel dimensions and molecular size become comparable to the range of several important forces including electrostatic and van der Waals forces. Small changes in properties such as the electric double layer or surface charge can significantly affect molecular transport through the channels. Based on these emerging properties, a variety of nanofluidic devices such as nanofluidic transistors, nanofluidic diodes or lab-on-a-chip devices have been developed3-7 with a diverse range of applications including water purification, biomolecular sensing, DNA separation, and rectified ion transport. Nanofluidic devices are typically fabricated using expensive lithography techniques or sacrificial templates. Here we report a carbon-based, three-dimensional nanofluidic transport membrane that enables gated, or on/off, control of the transport of organic molecular species and metal ions using an applied electrical potential. In the absence of an applied potential, both cationic and anionic molecules freely diffuse across the membrane via a concentration gradient. However, when an electrochemical potential is applied, the transport of ions through the membrane is inhibited.

Surwade, Sumedh P [ORNL] [ORNL; Chai, Songhai [ORNL] [ORNL; Choi, Jai-Pil [ORNL] [ORNL; Wang, Xiqing [ORNL] [ORNL; Lee, Jeseung [ORNL] [ORNL; Vlassiouk, Ivan V [ORNL] [ORNL; Mahurin, Shannon Mark [ORNL] [ORNL; Dai, Sheng [ORNL] [ORNL

2014-01-01T23:59:59.000Z

10

Feed gas contaminant control in ion transport membrane systems  

DOE Patents [OSTI]

Ion transport membrane oxidation system comprising an enclosure having an interior and an interior surface, inlet piping having an internal surface and adapted to introduce a heated feed gas into the interior of the enclosure, and outlet piping adapted to withdraw a product gas from the interior of the enclosure; one or more planar ion transport membrane modules disposed in the interior of the enclosure, each membrane module comprising mixed metal oxide material; and a preheater adapted to heat a feed gas to provide the heated feed gas to the inlet piping, wherein the preheater comprises an interior surface. Any of the interior surfaces of the enclosure, the inlet piping, and the preheater may be lined with a copper-containing metal lining. Alternatively, any of the interior surfaces of the inlet piping and the preheater may be lined with a copper-containing metal lining and the enclosure may comprise copper.

Carolan, Michael Francis (Allentown, PA); Minford, Eric (Laurys Station, PA); Waldron, William Emil (Whitehall, PA)

2009-07-07T23:59:59.000Z

11

NETL: Gasification - Development of Ion-Transport Membrane Oxygen  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Feed Systems Feed Systems Recovery Act: Development of Ion-Transport Membrane Oxygen Technology for Integration in IGCC and Other Advanced Power Generation Systems Air Products and Chemicals, Inc. Project Number: FC26-98FT40343 Project Description Air Products and Chemicals, Inc. is developing, scaling-up, and demonstrating a novel air separation technology for large-scale production of oxygen (O2) at costs that are approximately one-third lower than conventional cryogenic plants. An Ion Transport Membrane (ITM) Oxygen plant co-produces power and oxygen. A phased technology RD&D effort is underway to demonstrate all necessary technical and economic requirements for scale-up and industrial commercialization. The ITM Oxygen production technology is a radically different approach to producing high-quality tonnage oxygen and to enhance the performance of integrated gasification combined cycle and other advanced power generation systems. Instead of cooling air to cryogenic temperatures, oxygen is extracted from air at temperatures synergistic with power production operations. Process engineering and economic evaluations of integrated gasification combined cycle (IGCC) power plants comparing ITM Oxygen with a state-of-the-art cryogenic air separation unit are aimed to show that the installed capital cost of the air separation unit and the installed capital of IGCC facility are significantly lower compared to conventional technologies, while improving power plant output and efficiency. The use of low-cost oxygen in combustion processes would provide cost-effective emission reduction and carbon management opportunities. ITM Oxygen is an enabling module for future plants for producing coal derived shifted synthesis gas (a mixture of hydrogen [H2] and carbon dioxide [CO2]) ultimately for producing clean energy and fuels. Oxygen-intensive industries such as steel, glass, non-ferrous metallurgy, refineries, and pulp and paper may also realize cost and productivity benefits as a result of employing ITM Oxygen.

12

Experimental characterization of an Ion Transport Membrane (ITM) reactor for methane oxyfuel combustion  

E-Print Network [OSTI]

Ion Transport Membranes (ITM) which conduct both electrons and oxygen ions have been investigated experimentally for oxygen separation and fuel (mostly methane) conversion purposes over the last three decades. The fuel ...

Apo, Daniel Jolomi

2012-01-01T23:59:59.000Z

13

Numerical simulations of ion transport membrane oxy-fuel reactors for CO? capture applications  

E-Print Network [OSTI]

Numerical simulations were performed to investigate the key features of oxygen permeation and hydrocarbon conversion in ion transport membrane (ITM) reactors. ITM reactors have been suggested as a novel technology to enable ...

Hong, Jongsup

2013-01-01T23:59:59.000Z

14

Systems-level design of ion transport membrane oxy-combustion power plants  

E-Print Network [OSTI]

Oxy-fuel combustion, particularly using an integrated oxygen ion transport membrane (ITM), is a thermodynamically attractive concept that seeks to mitigate the penalties associated with CO 2 capture from power plants. ...

Mancini, Nicholas D. (Nicholas David)

2011-01-01T23:59:59.000Z

15

Antibiotic assisted molecular ion transport across a membrane in real time  

E-Print Network [OSTI]

Antibiotic assisted molecular ion transport across a membrane in real time Jian Liu, Xiaoming Shang of various chemical and physical phenomena as well as applications such as solar energy conversion, catalysis

Eisenthal, Kenneth B.

16

Ion transport membrane module and vessel system with directed internal gas flow  

DOE Patents [OSTI]

An ion transport membrane system comprising (a) a pressure vessel having an interior, an inlet adapted to introduce gas into the interior of the vessel, an outlet adapted to withdraw gas from the interior of the vessel, and an axis; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region; and (c) one or more gas flow control partitions disposed in the interior of the pressure vessel and adapted to change a direction of gas flow within the vessel.

Holmes, Michael Jerome (Thompson, ND); Ohrn, Theodore R. (Alliance, OH); Chen, Christopher Ming-Poh (Allentown, PA)

2010-02-09T23:59:59.000Z

17

Quantitative description of ion transport via plasma membrane of yeast and small cells  

E-Print Network [OSTI]

Modelling of ion transport via plasma membrane needs identification and quantitative understanding of the involved processes. Brief characterisation of ion transport systems of a yeast cell (Pma1, Ena1, TOK1, Nha1, Trk1, Trk2, non-selective cation conductance) and estimates concerning the number of molecules of each transporter per a cell allow predicting the corresponding ion flows. Comparison of ion transport in small yeast cell and several animal cell types is provided and importance of cell volume to surface ratio is stressed. Role of cell wall and lipid rafts is discussed in aspect of required increase in spatial and temporary resolution of measurements. Conclusions are formulated to describe specific features of ion transport in a yeast cell. Potential directions of future research are outlined based on the assumptions.

Volkov, Vadim

2012-01-01T23:59:59.000Z

18

Quantitative description of ion transport via plasma membrane of yeast and small cells  

E-Print Network [OSTI]

Modelling of ion transport via plasma membrane needs identification and quantitative understanding of the involved processes. Brief characterisation of ion transport systems of a yeast cell (Pma1, Ena1, TOK1, Nha1, Trk1, Trk2, non-selective cation conductance) and estimates concerning the number of molecules of each transporter per a cell allow predicting the corresponding ion flows. Comparison of ion transport in small yeast cell and several animal cell types is provided and importance of cell volume to surface ratio is stressed. Role of cell wall and lipid rafts is discussed in aspect of required increase in spatial and temporary resolution of measurements. Conclusions are formulated to describe specific features of ion transport in a yeast cell. Potential directions of future research are outlined based on the assumptions.

Vadim Volkov

2012-12-18T23:59:59.000Z

19

Transport of trivalent and hexavalent chromium through different ion-selective membranes in acidic aqueous media  

SciTech Connect (OSTI)

The aim of this work was to evaluate the transport of trivalent and hexavalent chromium through anion- and cation-selective membranes using two- and three-compartment electrodialysis cells. Tests were done with acidic solutions of trivalent chromium ions, Cr{sup 3+}, and hexavalent chromium ions, Cr{sub 2}O{sub 7}{sup 2{minus}}. In each situation the transport of metallic ions through the membrane was evaluated. In the tests with trivalent chromium, Nafion 417 and Selemion CMT cation-selective membranes were used, and in the tests with hexavalent chromium, Selemion AMT membrane was used. The influence of SO{sub 4}{sup 2{minus}} ions and of the concentration of H{sup +} ions in the solutions was also analyzed. Results showed the oxidation of the Cr{sup 3+} ion at the anode and the reduction of the Cr{sub 2}O{sub 7}{sup 2{minus}} ion at the cathode. The maximum yield in the process was reached when hexavalent chromium solutions were used in the absence of sulfate ions and a Selemion AMT membrane in a three-compartment cell.

Costa, R.F.D.; Rodrigues, M.A.S.; Ferreira, J.Z. [LACOR-PPGEM-UFRGS, Porto Alegre (Brazil)

1998-06-01T23:59:59.000Z

20

Thorium ions transport across Tri-n-butyl phosphate-benzene based supported liquid membranes  

SciTech Connect (OSTI)

Transport of Th(IV) ions across tri-n-butyl phosphate (TBP) benzene based liquid membranes supported in microporous hydrophobic polypropylene film (MHPF) has been studied. Various parameters such as variation of nitric acid concentration in the feed, TBP concentration in the membrane, and temperature on the given metal ions transport have been investigated. The effects of nitric acid and TBP concentrations on the distribution coefficient were also studied, and the data obtained were used to determine the Th ions-TBP complex diffusion coefficient in the membrane. Permeability coefficients of Th(IV) ions were also determined as a function of the TBP and nitric acid concentrations. The optimal conditions for the transport of Th(IV) ions across the membrane are 6 mol{sm_bullet}dm{sup -3} HNO{sub 3} concentration, 2.188 mol {center_dot} dm{sup -3} TBP concentration, and 25{degrees}C. The stoichiometry of the chemical species involved in chemical reaction during the transport of Th(IV) ions has also been studied.

Rasul, G.; Chaudry, M.A. [Pakistan Institute of Nuclear Chemistry, Islamabad (Pakistan); Afzal, M. [Quaid-I-Azam Univ., Islamabad (Pakistan)

1995-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes  

DOE Patents [OSTI]

Novel cathode, electrolyte and oxygen separation materials are disclosed that operate at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes based on oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

Jacobson, Allan J; Wang, Shuangyan; Kim, Gun Tae

2014-01-28T23:59:59.000Z

22

Transport Modeling of Membrane Extraction of Chlorinated Hydrocarbon from Water for Ion Mobility Spectrometry  

SciTech Connect (OSTI)

Membrane-extraction Ion Mobility Spectrometry (ME-IMS) is a feasible technique for the continuous monitoring of chlorinated hydrocarbons in water. This work studies theoretically the time-dependent characteristics of sampling and detection of trichloroethylene (TCE). The sampling is configured so that aqueous contaminants permeate through a hollow polydimethylsiloxane (PDMS) membrane and are carried away by a transport gas flowing through the membrane tube into IMS analyzer. The theoretical study is based on a two-dimensional transient fluid flow and mass transport model. The model describes the TCE mixing in the water, permeation through the membrane layer, and convective diffusion in the air flow inside membrane tube. The effect of various transport gas flow rates on temporal profiles of IMS signal intensity is investigated. The results show that fast time response and high transport yield can be achieved for ME-IMS by controlling the flow rate in the extraction membrane tube. These modeled time-response profiles are important for determining duty cycles of field-deployable sensors for monitoring chlorinated hydrocarbons in water.

Zhang, Wei [ORNL; Du, Yongzhai [ORNL; Feng, Zhili [ORNL; Xu, Jun [ORNL

2010-01-01T23:59:59.000Z

23

NETL: Gasification - Development of Ion-Transport Membrane Oxygen  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Program Background and Project Benefits Program Background and Project Benefits Gasification is used to convert a solid feedstock, such as coal, petcoke, or biomass, into a gaseous form, referred to as synthesis gas or syngas, which is primarily hydrogen and carbon monoxide. With gasification-based technologies, pollutants can be captured and disposed of or converted to useful products. Gasification can generate clean power by adding steam to the syngas in a water-gas-shift reactor to convert the carbon monoxide to carbon dioxide (CO2) and to produce additional hydrogen. The hydrogen and CO2 are separated-the hydrogen is used to make power and the CO2 is sent to storage, converted to useful products or used for EOR. In addition to efficiently producing electric power, a wide range of transportation fuels and chemicals can be produced from the cleaned syngas, thereby providing the flexibility needed to capitalize on the changing economic market. As a result, gasification provides a flexible technology option for using domestically available resources while meeting future environmental emission standards. Polygeneration plants that produce multiple products are uniquely possible with gasification technologies. The Gasification Systems program is developing technologies in three key areas to reduce the cost and increase the efficiency of producing syngas: (1) Feed Systems, (2) Gasifier Optimization and Plant Supporting Systems, and (3) Syngas Processing Systems.

24

FINAL REPORT:Observation and Simulations of Transport of Molecules and Ions Across Model Membranes  

SciTech Connect (OSTI)

During the this new grant we developed a robust methodology for investigating a wide range of properties of phospho-lipid bilayers. The approach developed is unique because despite using periodic boundary conditions, we can simulate an entire experiment or process in detail. For example, we can follow the entire permeation process in a lipid-membrane. This includes transport from the bulk aqueous phase to the lipid surface; permeation into the lipid; transport inside the lipid; and transport out of the lipid to the bulk aqueous phase again. We studied the transport of small gases in both the lipid itself and in model protein channels. In addition, we have examined the transport of nanocrystals through the lipid membrane, with the main goal of understanding the mechanical behavior of lipids under stress including water and ion leakage and lipid flip flop. Finally we have also examined in detail the deformation of lipids when under the influence of external fields, both mechanical and electrostatic (currently in progress). The important observations and conclusions from our studies are described in the main text of the report

MURAD, SOHAIL [University of Illinois at Chicago] [University of Illinois at Chicago; JAMESON, CYNTHIA J [University of Illinois at Chicago] [University of Illinois at Chicago

2013-10-22T23:59:59.000Z

25

Smart membranes for nitrate removal, water purification, and selective ion transportation  

DOE Patents [OSTI]

A computer designed nanoengineered membrane for separation of dissolved species. One embodiment provides an apparatus for treatment of a fluid that includes ions comprising a microengineered porous membrane, a system for producing an electrical charge across the membrane, and a series of nanopores extending through the membrane. The nanopores have a pore size such that when the fluid contacts the membrane, the nanopores will be in a condition of double layer overlap and allow passage only of ions opposite to the electrical charge across the membrane.

Wilson, William D. (Pleasanton, CA); Schaldach, Charlene M. (Pleasanton, CA); Bourcier, William L. (Livermore, CA); Paul, Phillip H. (Livermore, CA)

2009-12-15T23:59:59.000Z

26

Membrane Transport Chloride Transport Across Vesicle and Cell  

E-Print Network [OSTI]

Membrane Transport Chloride Transport Across Vesicle and Cell Membranes by Steroid-Based Receptors-established that molecules which transport cations across cell membranes (cationophores) can have potent biological effects the formation of an ion pair.[4a­g] Anion transport by purely electroneutral systems is still quite rare.[4j

Smith, Bradley D.

27

Oxygen Transport Ceramic Membranes Quarterly Report  

E-Print Network [OSTI]

/Reaction rates in Ion 21 Transport Membranes using Isotope Tracer and Transient Kinetic Techniques CONCLUSIONS 30Oxygen Transport Ceramic Membranes Quarterly Report January 2003 ­ March 2003 Principal Authors on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane

Eagar, Thomas W.

28

6 Ion Transport, Osmoregulation, and  

E-Print Network [OSTI]

177 6 Ion Transport, Osmoregulation, and Acid­Base Balance W.S. Marshall and M. Grosell CONTENTS I)............................................................................182 5. Skin and Opercular Membrane..................................................................................................183 2. Sea-Water Transport Mode -- Na+,K+-ATPase and Na+,K+, 2Cl­ Co-transport

Grosell, Martin

29

Journal of Membrane Science 239 (2004) 1726 Highly conductive ordered heterogeneous ion-exchange membranes  

E-Print Network [OSTI]

in the matrix required for reasonable ion transport through the membrane is 50­70 wt.% [2Journal of Membrane Science 239 (2004) 17­26 Highly conductive ordered heterogeneous ion-exchange membranes are used in electrodialysis (ED) as ion-selective membranes and in power sources (such as fuel

Freger, Viatcheslav "Slava"

30

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This report covers the following tasks: Task 1--Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints; Task 2--Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability; Task 3--Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres; Task 4--Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures; Task 5--Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability; and Task 6--Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2002-04-01T23:59:59.000Z

31

Characterization of a plasma membrane zinc transporter in rat brain  

E-Print Network [OSTI]

Ireland Ltd. Keywords: Ion transport; Membrane vesicles; Excitotoxicity; Zinc homeostasis; TransitionCharacterization of a plasma membrane zinc transporter in rat brain Robert A. Colvin* Department transport in the brain. This report provides convincing evidence of a zinc transporter in plasma membrane

32

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This is the third quarterly report on oxygen Transport Ceramic Membranes. In the following, the report describes the progress made by our university partners in Tasks 1 through 6, experimental apparatus that was designed and built for various tasks of this project, thermodynamic calculations, where applicable and work planned for the future. (Task 1) Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. (Task 2) Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. (Task 3) Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. (Task 4) Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. (Task 5) Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. (Task 6) Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2000-10-01T23:59:59.000Z

33

Composite oxygen transport membrane  

DOE Patents [OSTI]

A method of producing a composite oxygen ion membrane and a composite oxygen ion membrane in which a porous fuel oxidation layer and a dense separation layer and optionally, a porous surface exchange layer are formed on a porous support from mixtures of (Ln.sub.1-xA.sub.x).sub.wCr.sub.1-yB.sub.yO.sub.3-.delta. and a doped zirconia. In the porous fuel oxidation layer and the optional porous surface exchange layer, A is Calcium and in the dense separation layer A is not Calcium and, preferably is Strontium. Preferred materials are (La.sub.0.8Ca.sub.0.2).sub.0.95Cr.sub.0.5Mn.sub.0.5O.sub.3-.delta. for the porous fuel oxidation and optional porous surface exchange layers and (La.sub.0.8Sr.sub.0.2).sub.0.95Cr.sub.0.5Fe.sub.0.5O.sub.3-.delta. for the dense separation layer. The use of such materials allows the membrane to sintered in air and without the use of pore formers to reduce membrane manufacturing costs. The use of materials, as described herein, for forming the porous layers have application for forming any type of porous structure, such as a catalyst support.

Christie, Gervase Maxwell; Lane, Jonathan A.

2014-08-05T23:59:59.000Z

34

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

In the present quarter, oxygen transport perovskite ceramic membranes are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2002-07-01T23:59:59.000Z

35

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

In the present quarter, the possibility of using a more complex interfacial engineering approach to the development of reliable and stable oxygen transport perovskite ceramic membranes/metal seals is discussed. Experiments are presented and ceramic/metal interactions are characterized. Crack growth and fracture toughness of the membrane in the reducing conditions are also discussed. Future work regarding this approach is proposed are evaluated for strength and fracture in oxygen gradient conditions. Oxygen gradients are created in tubular membranes by insulating the inner surface from the reducing environment by platinum foils. Fracture in these test conditions is observed to have a gradient in trans and inter-granular fracture as opposed to pure trans-granular fracture observed in homogeneous conditions. Fracture gradients are reasoned to be due to oxygen gradient set up in the membrane, variation in stoichiometry across the thickness and due to varying decomposition of the parent perovskite. The studies are useful in predicting fracture criterion in actual reactor conditions and in understanding the initial evolution of fracture processes.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2003-01-01T23:59:59.000Z

36

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Processing of perovskites of LSC, LSF and LSCF composition for evaluation of mechanical properties as a function of environment are begun. The studies are to be in parallel with LSFCO composition to characterize the segregation of cations and slow crack growth in environmental conditions. La{sub 1-x}Sr{sub x}FeO{sub 3-d} has also been characterized for paramagnetic ordering at room temperature and the evolution of magnetic moments as a function of temperature are investigated. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2003-01-01T23:59:59.000Z

37

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals. This project has the following 6 main tasks: Task 1--Design, fabricate and evaluate ceramic to metal seals based on graded ceramic powder/metal braze joints. Task 2--Evaluate the effect of defect configuration on ceramic membrane conductivity and long term chemical and structural stability. Task 3--Determine materials mechanical properties under conditions of high temperatures and reactive atmospheres. Task 4--Evaluate phase stability and thermal expansion of candidate perovskite membranes and develop techniques to support these materials on porous metal structures. Task 5--Assess the microstructure of membrane materials to evaluate the effects of vacancy-impurity association, defect clusters, and vacancy-dopant association on the membrane performance and stability. Task 6--Measure kinetics of oxygen uptake and transport in ceramic membrane materials under commercially relevant conditions using isotope labeling techniques.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2001-12-01T23:59:59.000Z

38

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. Thermogravimetric analysis (TGA) was carried out on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} to investigate oxygen deficiency ({delta}) of the sample. The TGA was performed in a controlled atmosphere using oxygen, argon, carbon monoxide and carbon dioxide with adjustable gas flow rates. In this experiment, the weight loss and gain of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} was directly measured by TGA. The weight change of the sample was evaluated at between 600 and 1250 C in air or 1000 C as a function of oxygen partial pressure. The oxygen deficiencies calculated from TGA data as a function of oxygen activity and temperature will be estimated and compared with that from neutron diffraction measurement in air. The LSFT and LSFT/CGO membranes were fabricated from the powder obtained from Praxair Specialty Ceramics. The sintered membranes were subjected to microstructure analysis and hardness analysis. The LSFT membrane is composed of fine grains with two kinds of grain morphology. The grain size distribution was characterized using image analysis. In LSFT/CGO membrane a lot of grain pullout was observed from the less dense, porous phase. The hardness of the LSFT and dual phase membranes were studied at various loads. The hardness values obtained from the cross section of the membranes were also compared to that of the values obtained from the surface. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. Measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} as a function of temperature an oxygen partial pressure are reported. Further analysis of the dilatometry data obtained previously is presented. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The CO-CO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

S. Bandopadhyay; N. Nagabhushana; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-02-01T23:59:59.000Z

39

Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy  

Science Journals Connector (OSTI)

Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy ... Current status of ion exchange membranes for power generation from salinity gradients ...

Geoffrey M. Geise; Michael A. Hickner; Bruce E. Logan

2013-08-22T23:59:59.000Z

40

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the initial studies on newer compositions and also includes newer approaches to address various materials issues such as in metal-ceramic sealing. The current quarter's research has also focused on developing a comprehensive reliability model for predicting the structural behavior of the membranes in realistic conditions. In parallel to industry provided compositions, models membranes have been evaluated in varying environment. Of importance is the behavior of flaws and generation of new flaws aiding in fracture. Fracture mechanics parameters such as crack tip stresses are generated to characterize the influence of environment. Room temperature slow crack growth studies have also been initiated in industry provided compositions. The electrical conductivity and defect chemistry of an A site deficient compound (La{sub 0.55}Sr{sub 0.35}FeO{sub 3}) was studied. A higher conductivity was observed for La{sub 0.55}Sr{sub 0.35}FeO{sub 3} than that of La{sub 0.60}Sr{sub 0.40}FeO{sub 3} and La{sub 0.80}Sr{sub 0.20}FeO{sub 3}. Defect chemistry analysis showed that it was primarily contributed by a higher carrier concentration in La{sub 0.55}Sr{sub 0.35}FeO{sub 3}. Moreover, the ability for oxygen vacancy generation is much higher in La{sub 0.55}Sr{sub 0.35}FeO{sub 3} as well, which indicates a lower bonding strength between Fe-O and a possible higher catalytic activity for La{sub 0.55}Sr{sub 0.35}FeO{sub 3}. The program continued to investigate the thermodynamic properties (stability and phase separation behavior) and total conductivity of prototype membrane materials. The data are needed together with the kinetic information to develop a complete model for the membrane transport. Previous report listed initial measurements on a sample of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-x} prepared in-house by Praxair. Subsequently, a second sample of powder from a larger batch of sample were characterized and compared with the results from the previous batch.

S. Bandopadhyay; N. Nagabhushana; Thomas W. Eagar; Harold R. Larson; Raymundo Arroyave; X.-D Zhou; Y.-W. Shin; H.U. Anderson; Nigel Browning; Alan Jacobson; C.A. Mims

2003-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, in situ neutron diffraction was used to characterize the chemical and structural properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} (here after as L2SF55T) specimen, which was subject to measurements of neutron diffraction from room temperature to 900 C. It was found that space group of R3c yielded a better refinement than a cubic structure of Pm3m. Oxygen occupancy was nearly 3 in the region from room temperature to 700 C, above which the occupancy decreased due to oxygen loss. Dense OTM bars provided by Praxair were loaded to fracture at varying stress rates. Studies were done at room temperature in air and at 1000 C in a specified environment to evaluate slow crack growth behavior. The X-Ray data and fracture mechanisms points to non-equilibrium decomposition of the LSFCO OTM membrane. The non-equilibrium conditions could probably be due to the nature of the applied stress field (stressing rates) and leads to transition in crystal structures and increased kinetics of decomposition. The formations of a Brownmillerite or Sr2Fe2O5 type structures, which are orthorhombic are attributed to the ordering of oxygen vacancies. The cubic to orthorhombic transitions leads to 2.6% increase in strains and thus residual stresses generated could influence the fracture behavior of the OTM membrane. Continued investigations on the thermodynamic properties (stability and phase-separation behavior) and total conductivity of prototype membrane materials were carried out. The data are needed together with the kinetic information to develop a complete model for the membrane transport. Previously characterization, stoichiometry and conductivity measurements for samples of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} were reported. In this report, measurements of the chemical and thermal expansion as a function of temperature and p{sub O2} are described.

S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

2004-05-01T23:59:59.000Z

42

Catalyst containing oxygen transport membrane  

SciTech Connect (OSTI)

A composite oxygen transport membrane having a dense layer, a porous support layer and an intermediate porous layer located between the dense layer and the porous support layer. Both the dense layer and the intermediate porous layer are formed from an ionic conductive material to conduct oxygen ions and an electrically conductive material to conduct electrons. The porous support layer has a high permeability, high porosity, and a high average pore diameter and the intermediate porous layer has a lower permeability and lower pore diameter than the porous support layer. Catalyst particles selected to promote oxidation of a combustible substance are located in the intermediate porous layer and in the porous support adjacent to the intermediate porous layer. The catalyst particles can be formed by wicking a solution of catalyst precursors through the porous support toward the intermediate porous layer.

Christie, Gervase Maxwell; Wilson, Jamie Robyn; van Hassel, Bart Antonie

2012-12-04T23:59:59.000Z

43

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

In the present quarter, experiments are presented on ceramic/metal interactions of Zirconia/ Ni-B-Si system and with a thin Ti coating deposited on zirconia surface. Existing facilities were modified for evaluation of environmental assisted slow crack growth and creep in flexural mode. Processing of perovskites of LSC, LSF and LSCF composition were continued for evaluation of mechanical properties as a function of environment. These studies in parallel to those on the LSFCO composition is expect to yield important information on questions such as the role of cation segregation and the stability of the perovskite structure on crack initiation vs. crack growth. Studies have been continued on the La{sub 1-x}Sr{sub x}FeO{sub 3-d} composition using neutron diffraction and TGA studies. A transition from p-type to n-type of conductor was observed at relative low pO{sub 2}, at which the majority carriers changed from the holes to electrons because of the valence state decreases in Fe due to the further loss of oxygen. Investigation on the thermodynamic properties of the membrane materials are continued to develop a complete model for the membrane transport. Data obtained at 850 C show that the stoichiometry in La{sub 0.2}Sr{sub 0.8}Fe{sub 0.8}Cr{sub 0.2}O{sub 3-x} vary from {approx}2.85 to 2.6 over the pressure range studied. From the stoichiometry a lower limit of 2.6 corresponding to the reduction of all Fe{sup 4+} to Fe{sup 3+} and no reduction of Cr{sup 3+} is expected.

S. Bandopadhyay; N. Nagabhushana

2003-08-07T23:59:59.000Z

44

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped Ti-substituted perovskites, La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Ti{sub x}O{sub 3}, with 0 {le} x {le} 0.20, were investigated by neutron diffraction, magnetization, electric resistivity, and magnetoresistance (MR) measurements. All samples show a rhombohedral structure (space group R3C) from 10 K to room temperature. At room temperature, the cell parameters a, c and the unit cell volume increase with increasing Ti content. However, at 10 K, the cell parameter a has a maximum value for x = 0.10, and decreases for x > 0.10, while the unit cell volume remains nearly constant for x > 0.10. The average (Mn,Ti)-O bond length increases up to x = 0.15, and the (Mn,Ti)-O-(Mn,Ti) bond angle decreases with increasing Ti content to its minimum value at x = 0.15 at room temperature. Below the Curie temperature TC, the resistance exhibits metallic behavior for the x {le} 0.05 samples. A metal (semiconductor) to insulator transition is observed for the x {ge} 0.10 samples. A peak in resistivity appears below TC for all samples, and shifts to a lower temperature as x increases. The substitution of Mn by Ti decreases the 2p-3d hybridization between O and Mn ions, reduces the bandwidth W, and increases the electron-phonon coupling. Therefore, the TC shifts to a lower temperature and the resistivity increases with increasing Ti content. A field-induced shift of the resistivity maximum occurs at x {le} 0.10 compounds. The maximum MR effect is about 70% for La{sub 0.7}Sr{sub 0.3}Mn{sub 0.8}Ti{sub 0.2}O{sub 3}. The separation of TC and the resistivity maximum temperature T{sub {rho},max} enhances the MR effect in these compounds due to the weak coupling between the magnetic ordering and the resistivity as compared with La{sub 0.7}Sr{sub 0.3}MnO{sub 3}. The bulk densities of the membranes were determined using the Archimedes method. The bulk density was 5.029 and 5.57 g/cc for LSFT and dual phase membranes, respectively. The microstructure of the dual phase membrane was analyzed using SEM. It is evident from the micrograph that the microstructure is composed of dual phases. The dense circular regions are enclosed by the less dense, continuous phase which accommodates most of the pores. The pores are normally aggregated and found clustered along the dense regions where as the dense regions do not have pores. Upon closer observation of the micrograph it is revealed that the dense region has a clear circular cleavage or crack as their boundary. The circular cleavage clearly encompasses a dense region and which consists of no pore or any flaw that is visible. The size distribution of the dense, discontinuous regions is varying from 5 to 20 {micro}m with a D{sub 50} of 15 {micro}m. The grain size distribution was estimated from the micrographs using image analysis and a unimodal distribution of grains was observed with an average grain size of 1.99 {micro}m. The chemical compositions of the membranes were analyzed using EDS analysis and no other impurities were observed. The XRD analysis was carried out for the membranes and the phase purity was confirmed. The fracture toughness of LSFT membranes at room temperature has to be calculated using the Vickers indentation method. An electrochemical cell has been designed and built for measurements of the ionic conductivity by the use of blocking electrodes. Preliminary measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} are reported. Modifications to the apparatus to improve the data quality have been completed. Electron microscopy studies of the origin of the slow kinetics on reduction of ferrites have been initiated. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradient

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-05-01T23:59:59.000Z

45

Oxygen Transport Membranes  

SciTech Connect (OSTI)

The focus of this research was to develop new membrane materials by synthesizing different compounds and determining their defect structures, crystallographic structures and electrical properties. In addition to measuring electrical conductivity, oxygen vacancy concentration was also evaluated using thermogravimetry, Neutron diffraction and Moessbauer Spectroscopy. The reducing conditions (CO{sub 2}/CO/H{sub 2} gas mixtures with steam) as encountered in a reactor environment can be expected to have significant influence on the mechanical properties of the oxides membranes. Various La based materials with and without Ti were selected as candidate membrane materials for OTM. The maximum electrical conductivity of LSF in air as a function of temperature was achieved at < 600 C and depends on the concentration of Sr (acceptor dopant). Oxygen occupancy in LSF was estimated using Neutron diffractometry and Moessbauer Spectroscopy by measuring magnetic moment changes depending on the Fe{sup 3+} and Fe{sup 4+} ratio. After extensive studies of candidate materials, lanthanum ferrites (LSF and LSFT) were selected as the favored materials for the oxygen transport membrane (OTM). LSF is a very good material for an OTM because of its high electronic and oxygen ionic conductivity if long term stability and mechanical strength are improved. LSFT not only exhibits p-type behavior in the high oxygen activity regime, but also has n-type conduction in reducing atmospheres. Higher concentrations of oxygen vacancies in the low oxygen activity regime may improve the performance of LSFT as an OTM. The hole concentration is related to the difference in the acceptor and donor concentration by the relation p = [Sr'{sub La}]-[Ti{sm_bullet}{sub Fe}]. The chemical formulation predicts that the hole concentration is, p = 0.8-0.45 or 0.35. Experimental measurements indicated that p is about {approx} 0.35. The activation energy of conduction is 0.2 eV which implies that LSCF conducts via the small polaron conduction mechanism. Scanning transmission electron microscopy (STEM) and electron energy loss spectroscopy (EELS) were used to develop strategies to detect and characterize vacancy creation, dopant segregations and defect association in the oxygen conducting membrane material. The pO{sub 2} and temperature dependence of the conductivity, non-stoichiometry and thermal-expansion behavior of compositions with increasing complexity of substitution on the perovskite A and B sites were studied. Studies with the perovskite structure show anomalous behavior at low oxygen partial pressures (<10{sup -5} atm). The anomalies are due to non-equilibrium effects and can be avoided by using very strict criteria for the attainment of equilibrium. The slowness of the oxygen equilibration kinetics arises from two different mechanisms. In the first, a two phase region occurs between an oxygen vacancy ordered phase such as brownmillerite SrFeO{sub 2.5} and perovskite SrFeO{sub 3-x}. The slow kinetics is associated with crossing the two phase region. The width of the miscibility gap decreases with increasing temperature and consequently the effect is less pronounced at higher temperature. The preferred kinetic pathway to reduction of perovskite ferrites when the vacancy concentration corresponds to the formation of significant concentrations of Fe{sup 2+} is via the formation of a Ruddlesden-Popper (RP) phases as clearly observed in the case of La{sub 0.5}Sr{sub 0.5}FeO{sub 3-x} where LaSrFeO{sub 4} is found together with Fe. In more complex compositions, such as LSFTO, iron or iron rich phases are observed locally with no evidence for the presence of discrete RP phase. Fracture strength of tubular perovskite membranes was determined in air and in reducing atmospheric conditions. The strength of the membrane decreased with temperature and severity of reducing conditions although the strength distribution (Weibull parameter, m) was relatively unaltered. Surface and volume dominated the fracture origins and the overall fracture was purely transgranular. The dual phas

S. Bandopadhyay

2008-08-30T23:59:59.000Z

46

Active membrane having uniform physico-chemically functionalized ion channels  

DOE Patents [OSTI]

The present invention relates to a physicochemically-active porous membrane for electrochemical cells that purports dual functions: an electronic insulator (separator) and a unidirectional ion-transporter (electrolyte). The electrochemical cell membrane is activated for the transport of ions by contiguous ion coordination sites on the interior two-dimensional surfaces of the trans-membrane unidirectional pores. One dimension of the pore surface has a macroscopic length (1 nm-1000 .mu.m) and is directed parallel to the direction of an electric field, which is produced between the cathode and the anode electrodes of an electrochemical cell. The membrane material is designed to have physicochemical interaction with ions. Control of the extent of the interactions between the ions and the interior pore walls of the membrane and other materials, chemicals, or structures contained within the pores provides adjustability of the ionic conductivity of the membrane.

Gerald, II, Rex E; Ruscic, Katarina J; Sears, Devin N; Smith, Luis J; Klingler, Robert J; Rathke, Jerome W

2012-09-24T23:59:59.000Z

47

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, Moessbauer spectroscopy was used to study the local environmentals of LSFT with various level of oxygen deficiency. Ionic valence state, magnetic interaction and influence of Ti on superexchange are discussed Stable crack growth studies on Dense OTM bars provided by Praxair were done at elevated temperature, pressure and elevated conditions. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. An electrochemical cell has been designed and built for measurements of the Seebeck coefficient as a function of temperature and pressure. The initial measurements on La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} are reported. Neutron diffraction measurements of the same composition are in agreement with both the stoichiometry and the kinetic behavior observed in coulometric titration measurements. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The COCO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

2004-10-01T23:59:59.000Z

48

Salinity tolerance in plants: attempts to manipulate ion transport  

E-Print Network [OSTI]

Ion transport is the major determining factor of salinity tolerance in plants. A simple scheme of a plant cell with ion fluxes provides basic understanding of ion transport and the corresponding changes of ion concentrations under salinity. The review describes in detail basic principles of ion transport for a plant cell, introduces set of transporters essential for sodium and potassium uptake and efflux, analyses driving forces of ion transport and compares ion fluxes measured by several techniques. Study of differences in ion transport between salt tolerant halophytes and salt-sensitive plants with an emphasis on transport of potassium and sodium via plasma membranes offers knowledge for increasing salinity tolerance. Effects of salt stress on ion transport properties of membranes show huge opportunities for manipulating ion transport. Several attempts to overexpress or knockout ion transporters for changing salinity tolerance are described. Future perspectives are questioned with more attention given to potential candidate ion channels and transporters for altered expression. The potential direction of increasing salinity tolerance by modifying ion channels and transporters is discussed and questioned. An alternative approach from synthetic biology is to modify the existing membrane transport proteins or create new ones with desired properties for transforming agricultural crops. The approach had not been widely used earlier and leads also to theoretical and pure scientific aspects of protein chemistry, structure-function relations of membrane proteins, systems biology and physiology of stress and ion homeostasis.

Vadim Volkov

2014-11-06T23:59:59.000Z

49

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In this report, in situ neutron diffraction was used to characterize the chemical and structural properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} (here after as L2SF55T) specimen, which was subject to measurements of neutron diffraction from room temperature to 900 C in N{sub 2}. Space group of R3c was found to result in a better refinement and is used in this study. The difference for crystal structure, lattice parameters and local crystal chemistry for LSFT nearly unchanged when gas environment switched from air to N{sub 2}. Stable crack growth studies on Dense OTM bars provided by Praxair were done at room temperature in air. A bridge-compression fixture was fabricated to achieve stable pre-cracks from Vickers indents. Post fracture evaluation indicated stable crack growth from the indent and a regime of fast fracture. Post-fracture X-ray data of the OTM fractured at 1000 C in environment were refined by FullProf code and results indicate a distortion of the parent cubic perovskite to orthorhombic structure with reduced symmetry. TGA-DTA studies on the post-fracture samples also indicated residual effect arising from the thermal and stress history of the samples. The thermal and chemical expansion of La{sub 0.2}Sr{sub 0.8}Fe{sub 0.55}Ti{sub 0.45}O{sub 3-{delta}} were studied at 800 {le} T {le} 1000 C and at {approx} 1 x 10{sup -15} {le} pO{sub 2} {le} 0.21 atm. The thermal expansion coefficient of the sample was calculated from the dilatometric analysis in the temperature range between room temperature and 1200 C in air. A series of isotope transients under air separation mode (small gradient) were completed on the membrane of LSCrF-2828 at 900 C. Low pO{sub 2} atmospheres based on with CO-CO{sub 2} mixtures have also been admitted to the delivery side of the LSCrF-2828 membrane to produce the gradients which exist under syngas generation conditions. The CO-CO{sub 2} mixtures have normal isotopic {sup 18}O abundances. The evolution of {sup 18}O on the delivery side in these experiments after an {sup 18}O pulse on the air side reveals a wealth of information about the oxygen transport processes.

S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; Q. Cai; J. Yang; W.B. Yelon; W.J. James; H.U. Anderson; Alan Jacobson; C.A. Mims

2004-05-01T23:59:59.000Z

50

Transport study of hafnium(IV) and zirconium(IV) ions mutual separation by using Tri-n-butyl phosphate-xylene-based supported liquid membranes  

SciTech Connect (OSTI)

A Hf transport study through supported liquid membranes has been carried out to determine flux and permeability data for this metal ion. Tri-n-butyl phosphate (TBP)-xylene-based liquid membranes supported in polypropylene hydrophobic microporous film have been used. These data for hafnium and the previous data for zirconium have furnished the Zr to Hf flux ratio (S) as a function of nitric acid and TBP concentrations of the order of 12 in a single stage at room temperature. Optimum conditions for the separation of these two metal ions appear to 5-6 TBP mol/dm{sup 3} HNO{sub 3}, concentrations {le} 2.93 mol/dm{sup 3}, and 10C. The value of S from an aqueous solution containing 2.4% Hf with respect to Zr has been found to be >125 at 10C and 1.78 mol/dm{sup 3} TBP concentration in the membrane. The technique appears to be feasible for purification of Zr respect to Hf or vice versa.

Chaudry, M.A.; Ahmed, B. (Pakistan Inst. of Nuclear Science and Technology, Islamabad (Pakistan))

1992-02-01T23:59:59.000Z

51

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In the current research, the electrical conductivity and Seebeck coefficient were measured as a function of temperature in air. Based on these measurements, the charge carrier concentration, net acceptor dopant concentration, activation energy of conduction and mobility were estimated. The studies on the fracture toughness of the LSFT and dual phase membranes at room temperature have been completed and reported previously. The membranes that are exposed to high temperatures at an inert and a reactive atmosphere undergo many structural and chemical changes which affects the mechanical properties. To study the effect of temperature on the membranes when exposed to an inert environment, the membranes (LAFT and Dual phase) were heat treated at 1000 C in air and N{sub 2} atmosphere and hardness and fracture toughness of the membranes were studied after the treatment. The indentation method was used to find the fracture toughness and the effect of the heat treatment on the mechanical properties of the membranes. Further results on the investigation of the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appears to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. 2-D modeling of oxygen movement has been undertaken in order to fit isotope data. The model will serve to study ''frozen'' profiles in patterned or composite membranes.

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-11-01T23:59:59.000Z

52

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

In this quarter a systematic analysis on the decomposition behavior of the OTM membranes at air and nitrogen were initiated to understand the structural and stoichiometric changes associated with elevated temperatures. Evaluation of the flexural strengths using 4-point bend test was also started for the dual phase membranes. Initial results on the synthesis of dual phase composite materials have been obtained. The measurements have focused on the compatibility of mixed conductors with the pure ionic conductors yttria stabilized zirconia (YSZ) and gadolinium doped ceria (GDC). The initial results obtained for three different mixed conductors suggest that (GDC) is the better choice. A new membrane permeation system has been designed and tested and sintering studies of biphasic systems are in progress.

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2006-05-01T23:59:59.000Z

53

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This is the fifth quarterly report on a new study to develop a ceramic membrane/metal joint. Results of wetting experiments on commercially available Nickel based brazing alloys on perovskite surfaces are described. Additionally, experimental and numerical investigations on the strength of concentric ceramic/metal joints are presented.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2001-02-01T23:59:59.000Z

54

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

This is the fourth quarterly report on a new study to develop a ceramic membrane/metal joint. The first experiments using the La-Sr-Fe-O ceramic are reported. Some of the analysis performed on the samples obtained are commented upon. A set of experiments to characterize the mechanical strength and thermal fatigue properties of the joints has been designed and begun. Finite element models of joints used to model residual stresses are described.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2000-07-01T23:59:59.000Z

55

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. In the previous research, the reference point of oxygen occupancy was determined and verified. In the current research, the oxygen occupancy was investigated at 1200 C as a function of oxygen activity and compared with that at 1000 C. The cause of bumps at about 200 C was also investigated by using different heating and cooling rates during TGA. The fracture toughness of LSFT and dual phase membranes at room temperature is an important mechanical property. Vicker's indentation method was used to evaluate this toughness. Through this technique, a K{sub Ic} (Mode-I Fracture Toughness) value is attained by means of semi-empirical correlations between the indentation load and the length of the cracks emanating from the corresponding Vickers indentation impression. In the present investigation, crack propagation behavior was extensively analyzed in order to understand the strengthening mechanisms involved in the non-transforming La based ceramic composites. Cracks were generated using Vicker's indenter and used to identify and evaluate the toughening mechanisms involved. Preliminary results of an electron microscopy study of the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appear to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. Modeling of the isotopic transients on operating membranes (LSCrF-2828 at 900 C) and a ''frozen'' isotope profile have been analyzed in conjunction with a 1-D model to reveal the gradient in oxygen diffusivity through the membrane under conditions of high chemical gradients.

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-08-01T23:59:59.000Z

56

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and studies on newer composition of Ti doped LSF. The in situ electrical conductivity and Seebeck coefficient measurements were made on LSFT at 1000 and 1200 C over the oxygen activity range from air to 10{sup -15} atm. The electrical conductivity measurements exhibited a p to n type transition at an oxygen activity of 1 x 10{sup -10} at 1000 C and 1 x 10{sup -6} at 1200 C. Thermogravimetric studies were also carried out over the same oxygen activities and temperatures. Based on the results of these measurements, the chemical and mechanical stability range of LSFT were determined and defect structure was established. The studies on the fracture toughness of the LSFT and dual phase membranes exposed to air and N{sub 2} at 1000 C was done and the XRD and SEM analysis of the specimens were carried out to understand the structural and microstructural changes. The membranes that are exposed to high temperatures at an inert and a reactive atmosphere undergo many structural and chemical changes which affect the mechanical properties. A complete transformation of fracture behavior was observed in the N{sub 2} treated LSFT samples. Further results to investigate the origin of the slow kinetics on reduction of ferrites have been obtained. The slow kinetics appear to be related to a non-equilibrium reduction pathway that initially results in the formation of iron particles. At long times, equilibrium can be reestablished with recovery of the perovskite phase. Recent results on transient kinetic data are presented. The 2-D modeling of oxygen movement has been undertaken in order to fit isotope data. The model is used to study ''frozen'' profiles in patterned or composite membranes.

S. Bandopadhyay; T. Nithyanantham; X.-D Zhou; Y-W. Sin; H.U. Anderson; Alan Jacobson; C.A. Mims

2005-02-01T23:59:59.000Z

57

Interpenetrating polymer network ion exchange membranes and method for preparing same  

DOE Patents [OSTI]

Interpenetrating polymer network ion exchange membranes include a microporous polymeric support film interpenetrated by an ion exchange polymer and are produced by absorbing and polymerizing monomers within the support film. The ion exchange polymer provides ion exchange ligands at the surface of and throughout the support film which have sufficient ligand mobility to extract and transport ions across the membrane.

Alexandratos, Spiro D. (Knoxville, TN); Danesi, Pier R. (Vienna, AT); Horwitz, E. Philip (Naperville, IL)

1989-01-01T23:59:59.000Z

58

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

Ti doping on La{sub 1-x}Sr{sub x}FeO{sub 3-{delta}} (LSF) tends to increase the oxygen equilibration kinetics of LSF in lower oxygen activity environment because of the high valence state of Ti. However, the addition of Ti decreases the total conductivity because the acceptor ([Sr{prime}{sub La}]) is compensated by the donor ([Ti{sub Fe}{sup {sm_bullet}}]) which decreases the carrier concentration. The properties of La{sub 0.2}Sr{sub 0.8}Fe{sub 1-x}Ti{sub x}O{sub 3-{delta}} (LSFT, x = 0.45) have been experimentally and theoretically investigated to elucidate (1) the dependence of oxygen occupancy and electrochemical properties on temperature and oxygen activity by thermogravimetric analysis (TGA) and (2) the electrical conductivity and carrier concentration by Seebeck coefficient and electrical measurements. In the present study, dual phase (La{sub 0.2}Sr{sub 0.8}Fe{sub 0.6}Ti{sub 0.4}O{sub 3-{delta}}/Ce{sub 0.9}Gd{sub 0.1}O{sub 2-{delta}}) membranes have been evaluated for structural properties such as hardness, fracture toughness and flexural strength. The effect of high temperature and slightly reducing atmosphere on the structural properties of the membranes was studied. The flexural strength of the membrane decreases upon exposure to slightly reducing conditions at 1000 C. The as-received and post-fractured membranes were characterized using XRD, SEM and TG-DTA to understand the fracture mechanisms. Changes in structural properties of the composite were sought to be correlated with the physiochemical features of the two-phases. We have reviewed the electrical conductivity data and stoichiometry data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} some of which was reported previously. Electrical conductivity data for La{sub 0.2}Sr{sub 0.8}Cr{sub 0.2}Fe{sub 0.8}O{sub 3-{delta}} (LSCrF) were obtained in the temperature range, 752 {approx} 1055 C and in the pO{sub 2} range, 10{sup -18} {approx} 0.5 atm. The slope of the plot of log {sigma} vs. log pO{sub 2} is {approx} 1/5 in the p-type region, pO{sub 2} = 10{sup -5} {approx} 10{sup -1} atm. The pO{sub 2} at which the p-n transition is observed increases with increasing temperature. The activation energy for ionic conduction was estimated to be 0.86 eV from an Arrhenius plot of the minimum conductivity vs. reciprocal temperature. At temperatures below 940 C, a plateau in the conductivity isotherm suggests the presence of a two-phase region. Most likely, phase separation occurs to form a mixture of a perovskite phase and an oxygen vacancy ordered phase related to brownmillerite. Additional data for the oxygen non stoichiometry are presented.

S. Bandopadhyay; T. Nithyanantham

2006-12-31T23:59:59.000Z

59

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

A non-agglomerated and nanocrystalline-sized powder was successfully produced using ethylene glycol nitrate methods. The LSFT powder prepared using this method exhibits well dispersed and nano-sized particles about 100-200 nm. The density of LSFT sintered at 1300 C was about 90% of the theoretical density at which is 100 C less than that of the previous LSFT which was sintered at 1400 C. The sample sintered at 1400 C exhibited the evidence of a liquid phase at the grain boundaries and 2nd phase formation which probably caused low mechanical stability. The electrical conductivity and Seebeck coefficient were measured as a function of temperature. The LSFT-CGO specimens were cut from the as sintered bars and used for the evaluation of Mechanical Properties after polishing. The effect of strain rate on the flexural strength of the LSFT-CGO test specimens was studied. Three strain rates 6, 60 and 600 {micro}m/ min were chosen for this study. It is observed from the results that with increasing cross head speed the membrane takes higher loads to fail. A reduction in the strength of the membrane was observed at 1000 C in N{sub 2}. Two different routes were investigated to synthesis GDC using either formate or carbonate precursors. The precursor and CGO particle morphologies were examined by scanning electron microscopy. The thermal decomposition behaviors of Ce(Gd)(HCOO){sub 3} and Ce(Gd)(CO{sub 3})(OH) were determined by thermogravimetric analysis (TGA) at a rate of 3 C/min in air. The X-ray powder diffraction patterns of the precursor and CGO were collected and nitrogen adsorption isotherms were measured. Conductivity measurements were made by AC impedance spectroscopy on sintered disks in air using platinum electrodes.

S. Bandopadhyay; T. Nithyanantham

2006-06-30T23:59:59.000Z

60

Studies on the in situ electrooxidation and selective permeation of cerium(IV) across a bulk liquid membrane containing tributyl phosphate as the ion transporter  

SciTech Connect (OSTI)

The results of experiments carried out to develop a liquid membrane (LM) technique for the extractive permeation of cerium from nitric acid solutions are described. In-situ electrooxidation of Ce{sup 3+} to extractable Ce{sup 4+} and its transport across bulk LM (BLM) composed of tri-n-butyl phosphate (TBP)/dodecane mixtures was systematically studied under varied hydrodynamical and chemical conditions. The permeability of metal ions across the BLM was dependent on the efficiency of extraction, ionic activity of feed solutions, stirring rate, composition of the receiving phase, etc. The transport rates were found to vary linearly (a log-log correlation) with the cation concentration in feed solutions and concentration of TBP in BLM. A permeation velocity equation for cerium ion through the membrane has been proposed. More than 90% permeation of Ce with a maximum flux of 8.63 x 10{sup {minus}5} mol/m{sup 2}/s could be accomplished under the experimental conditions: stirring rates at feed and strip solutions were 380 and 300 rpm, respectively; feed was 1 mol/dm{sup 3} of HNO{sub 3} containing 0.005 mol/dm{sup 3} Ce(NO{sub 3}){sub 3}; LM contained 30% TBP/dodecane; and the receiving phase was distilled water. Radiochemically pure Ce-144 was partitioned from the Ce-Am mixture obtained by extraction chromatographic fractioning of high level radioactive waste. This also resulted in the purification of Am-241 in the feed solution with a decontamination factor of {approximately} 12 from Ce.

Kedari, C.S.; Pandit, S.S.; Ramanujam, A. [Bhabha Atomic Research Centre, Trombay (India). Fuel Reprocessing Div.] [Bhabha Atomic Research Centre, Trombay (India). Fuel Reprocessing Div.

1999-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Oxygen Transport Ceramic Membranes  

SciTech Connect (OSTI)

The present quarterly report describes some of the investigations on the structural properties of dense OTM bars provided by Praxair and initial studies on newer composition of Ti doped LSF. Dense OTM bars provided by Praxair were loaded to fracture at varying stress rates. Studies were done at room temperature in air and at 1000 C in a specified environment to evaluate slow crack growth behavior. In addition, studies were also begun to obtain reliable estimates of fracture toughness and stable crack growth in specific environments. Newer composition of Ti doped LSF membranes were characterized by neutron diffraction analysis. Quench studies indicated an apparent correlation between the unit cell volume and oxygen occupancy. The studies however, indicated an anomaly of increasing Fe/Ti ratio with change in heat treatment. Ti doped LSF was also characterized for stoichiometry as a function of temp and pO{sub 2}. The non stoichiometry parameter {delta} was observed to increase almost linearly on lowering pO{sub 2} until a ideal stoichiometric composition of {delta} = 0.175 was approached.

S. Bandopadhyay; N. Nagabhushana; X.-D Zhou; W.B. Yelon; H.U. Anderson; Alan Jacobson; C.A. Mims

2004-02-01T23:59:59.000Z

62

Electric Field Modulation of the Membrane Potential in Solid-State Ion Channels  

E-Print Network [OSTI]

channel. KEYWORDS: Nanochannel, membrane potential, electrofluidic gating, ion transport, salinityElectric Field Modulation of the Membrane Potential in Solid-State Ion Channels Weihua Guan a rapid flow of ions across the cell membrane. Normal physiological functions, such as generating action

Reed, Mark

63

Transport of Alkali Halides through a Liquid Organic Membrane Containing a Ditopic Salt-Binding Receptor  

E-Print Network [OSTI]

in the solid state as contact ion pairs. Transport experiments, using a supported liquid membrane and high saltTransport of Alkali Halides through a Liquid Organic Membrane Containing a Ditopic Salt and anion receptors. All transport systems exhibit the same qualitative order of ion selectivity; that is

Smith, Bradley D.

64

An increasing number of synthetic compounds have been shown to facilitate ion and polar molecule transport across  

E-Print Network [OSTI]

transport of ions and polar molecules across biological membranes is essential for normal cell function synthetic transporters shown to be active in both model bilayers and cellular membranes. Mechanism of ion simulations of unassisted Na+ and Cl­ ion transport across a bilayer membrane. As the ion enters the outer

Smith, Bradley D.

65

Charge Inversion, Water Splitting, and Vortex Suppression Due to DNA Sorption on Ion-Selective Membranes and Their Ion-Current  

E-Print Network [OSTI]

These membranes show a unique property of selective ion transport through the nanopores of IEMs embedded to saturate at a limiting current beyond a critical cross-membrane voltage drop as a result of the ion-transport-Selective Membranes and Their Ion-Current Signatures Zdenek Slouka, Satyajyoti Senapati, Yu Yan, and Hsueh-Chia Chang

Chang, Hsueh-Chia

66

Structures for Three Membrane Transport Proteins Yield Functional Insights  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Structures for Three Membrane Structures for Three Membrane Transport Proteins Yield Functional Insights Structures for Three Membrane Transport Proteins Yield Functional Insights Print Wednesday, 27 January 2010 00:00 Cells depend on contact with their outside environment in order to thrive. Two examples illustrate why: In one, information needed to guide cellular processes is constantly transmitted across cell membranes by specialized proteins, and in the other, maintaining the right gradient of ions across the membrane is a process critical to the life and death of a cell. Membrane transport proteins-functioning either as channels or transporters-are the gatekeepers that control contact with the world outside the cell by catalyzing the flow of ions and molecules across cell membranes. Malfunctioning transport proteins can lead to cancer, inflammatory, and neurological diseases. Despite their importance in cell function and in a multitude of physiological processes such as sensing pain, there are still many unknowns about how they function. Recently, in an impressive series of three papers in Nature and Science, researchers at the Oregon Health and Science University delineated the structures of three transporter proteins, one of which had never before been characterized structurally in such detail. The structures were solved using ALS Beamlines 5.0.2, 8.2.1, and 8.2.2.

67

Nanostructured Silicon Membranes for Control of Molecular Transport  

SciTech Connect (OSTI)

A membrane that allows selective transport of molecular species requires precise engineering on the nanoscale. Membrane permeability can be tuned by controlling the physical structure of the pores. Here, a combination of electron-beam and optical lithography, along with cryogenic deep reactive ion etching, has been used to fabricate silicon membranes that are physically robust, have uniform pore-sizes, and are directly integrated into a microfluidic network. Additional reductions in pore size were achieved using plasma enhanced chemical vapor deposition of silicon dioxide to coat membrane surfaces. Cross sectioning of the membranes using focused ion beam milling was used to determine the physical shape of the membrane pores before and after coating.

Srijanto, Bernadeta R [ORNL] [ORNL; Retterer, Scott T [ORNL] [ORNL; Fowlkes, Jason Davidson [ORNL] [ORNL; Doktycz, Mitchel John [ORNL] [ORNL

2010-01-01T23:59:59.000Z

68

Charge Transport through a Novel Zeolite Y Membrane by a Self-Exchange Process Hyunjung Lee and Prabir K. Dutta*  

E-Print Network [OSTI]

Charge Transport through a Novel Zeolite Y Membrane by a Self-Exchange Process Hyunjung Lee-photoresist-coated membranes were found. Accessibility of the intrazeolitic volume was examined by ion exchange and for optimally illuminated membranes was comparable to uncoated membranes. Charge transport through the membrane

Dutta, Prabir K.

69

How the Membrane Protein AmtB Transports Ammonia  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

How the Membrane Protein AmtB Transports Ammonia Print How the Membrane Protein AmtB Transports Ammonia Print Membrane proteins provide molecular-sized entry and exit portals for the various substances that pass into and out of cells. While life scientists have solved the structures of protein channels for ions, uncharged solutes, and even water, up to now they have only been able to guess at the precise mechanisms by which gases (such as NH3, CO2, O2, NO, N2O, etc.) cross biological membranes. But, with the first high-resolution structure of a bacterial ammonia transporter (AmtB), determined by a team in the Stroud group from the University of California, San Francisco, it is now known that this family of transporters conducts ammonia by stripping off the proton from the ammonium (NH4+) cation and conducting the uncharged NH3 "gas."

70

Theoretical and experimental analysis of conductivity, ion diffusion and molecular transport during cell electroporation --Relation between short-lived and  

E-Print Network [OSTI]

electric field, which enables transport of molecules and ions across the cell membrane. Several and ions due to the hydrophobic nature of the lipid bilayer. Transport through the membrane occurs only for certain molecules and ions through membrane channels by means of diffusion or by active transport. However

Ljubljana, University of

71

pH dependence and compartmentalization of zinc transported across plasma membrane of rat cortical neurons  

E-Print Network [OSTI]

pH dependence and compartmentalization of zinc transported across plasma membrane of rat corticalH dependence and compartmental- ization of zinc transported across plasma membrane of rat cortical neurons. Am; ion transport; transition elements; primary culture IT IS KNOWN THAT Zn2 can enter neurons by two

72

Ionic transport in nanocapillary membrane systems Vikhram V. Swaminathan Larry R. Gibson II  

E-Print Network [OSTI]

. Keywords Membranes Á Nanostructures Á Nanofluidics Á Microfluidics Á Ion transport Á Electrokinetics Á lREVIEW Ionic transport in nanocapillary membrane systems Vikhram V. Swaminathan · Larry R. Gibson / Accepted: 23 May 2012 ? Springer Science+Business Media B.V. 2012 Abstract Species transport

73

Anion Exchange Membranes - Transport/Conductivity  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Fundamental understanding Fundamental understanding * Driving membranes towards applications Anion Exchange Membranes - Transport/Conductivity High Priority * A need for a standard/available AEM (similar to Nafion in PEMs) * Define standard experimental conditions and protocols * A need for much more fundamental studies in transport mechanisms and mechanical properties * A need to develop much more new AEMs with alternative chemistries (new cation and backbone chemistries) Fundamental Studies * TRANSPORT * Conductivity (pure OH - hard to measure) * Water content, λ * Diffusion coefficients, NMR * Drag coefficients * Transference * Solubility * Fundamental transport mechanisms for anion and water transport * Computational Modeling * MORPHOLOGY/CHEMISTRY * Vibrational Spectroscopy: FTIR, Raman

74

Microfluidic Systems with Ion-Selective Membranes  

E-Print Network [OSTI]

treatment processes such as electrodialysis and elec- trodeionization (1). These membranes are natural gradients, internal/external ion enrichment, extended polarized layers, surface electroconvection, water effects. More than 70 years ago, ion-selective mem- branes started to be used in industrial water

Chang, Hsueh-Chia

75

Perchlorate Degradation Using Partially Oxidized Titanium Ions and Ion Exchange Membrane Hybrid System  

E-Print Network [OSTI]

. To enhance the overall rate of reaction, high concentrations of acid and Ti(III) are needed, but transport of hydrogen ions through the anion permeable membrane was observed and would be greater at higher acid concentrations. The proposed mathematical model...

Park, Sung Hyuk

2011-08-08T23:59:59.000Z

76

Turbulent transport of energetic ions  

SciTech Connect (OSTI)

Approaching ITER operation, the issue of anomalous transport of fast particles becomes more and more important. This is partly because the ITER heating and current drive system relies heavily on neutral beam injection. Moreover burning plasmas are heated by fast fusion {alpha} particles.Fusion {alpha} particles are characterised by a fixed energy and an isotropic velocity distribution. Therefore they have gyroradii one magnitude larger than the thermal ions. The dependency of the particle diffusion of {alpha} test particles on the Kubo number K = VExB{tau}c/{lambda}c (VExB mean E x B velocity, {tau}c, {lambda}c correlation time and length of the turbulent potential) is presented. For different turbulent regimes, different dependency of the diffusion on the gyroradius is found. For large Kubo numbers, the transport is found to remain constant for gyroradii up to the correlation length of the potential, whereas it is drastically reduced in the small Kubo number regime.In the second part, a model for beam ions injected along the equilibrium magnetic field is described. The beam ions are treated gyrokinetically in a self-consistent way with the equilibrium distribution function taken as a shifted Maxwellian. The implications of such a model for the Vlasov equation, the field equations, and the calculation of moments and fluxes are discussed. Linear and nonlinear results, obtained with the gyrokinetic flux tube code GENE show the existence of a new instability driven by fast beam ions. The instability has a maximum growth rate at perpendicular wave numbers of ky{rho}s {approx} 0.15 and depends mainly on the beam velocity and the density gradient of the beam ions. This instability leads to a replacement of bulk ion particle transport by fast ion particle transport, connected to a strongly enhanced heat flux. In the presence of this instability, the turbulent particle and heat transport is dominated by fast ions.

Dannert, Tilman; Hauff, Thilo; Jenko, Frank; Guenter, Sibylle [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

2006-11-30T23:59:59.000Z

77

The Role of Sarcolipin and ATP in the Transport of Phosphate Ion into the Sarcoplasmic Reticulum  

E-Print Network [OSTI]

The Role of Sarcolipin and ATP in the Transport of Phosphate Ion into the Sarcoplasmic Reticulum toward chloride ion when incorporated in a mercury-supported tethered bilayer lipid membrane (tBLM). ItsM. Phenylphosphonium ion and adenosine monophosphate exert an inhibitory effect on membrane permeabilization

Thomas, David D.

78

Morphology of Ion Exchange Membranes  

Science Journals Connector (OSTI)

......the HjO,- treatment of the ion exchange...and rinsed with water. After drying...Determined in sea water at 25 C by electrodialysis. Fig. 2. Neosepta...with deionized water, treated with...prepared by the treatment of the cation......

Yoshikazu HORI; Toru NAKATANI; Yukio MIZUTANI

1986-10-01T23:59:59.000Z

79

Oxy-combustion: Oxygen Transport Membrane Development  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

combustion: Oxygen Transport combustion: Oxygen Transport Membrane Development Background The mission of the U.S. Department of Energy's (DOE) Existing Plants, Emissions & Capture (EPEC) Research & Development (R&D) Program is to develop innovative environmental control technologies to enable full use of the nation's vast coal reserves, while at the same time allowing the current fleet of coal-fired power plants to comply with existing and emerging environmental regulations. The EPEC R&D

80

Composite oxygen ion transport element  

SciTech Connect (OSTI)

A composite oxygen ion transport element that has a layered structure formed by a dense layer to transport oxygen ions and electrons and a porous support layer to provide mechanical support. The dense layer can be formed of a mixture of a mixed conductor, an ionic conductor, and a metal. The porous support layer can be fabricated from an oxide dispersion strengthened metal, a metal-reinforced intermetallic alloy, a boron-doped Mo.sub.5Si.sub.3-based intermetallic alloy or combinations thereof. The support layer can be provided with a network of non-interconnected pores and each of said pores communicates between opposite surfaces of said support layer. Such a support layer can be advantageously employed to reduce diffusion resistance in any type of element, including those using a different material makeup than that outlined above.

Chen, Jack C. (Getzville, NY); Besecker, Charles J. (Batavia, IL); Chen, Hancun (Williamsville, NY); Robinson, Earil T. (Mentor, OH)

2007-06-12T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Heat transport through ion crystals  

E-Print Network [OSTI]

We study the thermodynamical properties of crystals of trapped ions which are laser cooled to two different temperatures in two separate regions. We show that these properties strongly depend on the structure of the ion crystal. Such structure can be changed by varying the trap parameters and undergoes a series of phase transitions from linear to zig-zag or helicoidal configurations. Thus, we show that these systems are ideal candidates to observe and control the transition from anomalous to normal heat transport. All structures behave as `heat superconductors', with a thermal conductivity increasing linearly with system size and a vanishing thermal gradient inside the system. However, zig-zag and helicoidal crystals turn out to be hyper sensitive to disorder having a linear temperature profile and a length independent conductivity. Interestingly, disordered 2D ion crystals are heat insulators. Sensitivity to disorder is much smaller in the 1D case.

Nahuel Freitas; Esteban Martinez; Juan Pablo Paz

2013-12-23T23:59:59.000Z

82

Alkylsulfonates as Probes of Uncoupling Protein Transport ION PAIR TRANSPORT DEMONSTRATES THAT DIRECT H TRANSLOCATION BY UCP1 IS NOT NECESSARY  

E-Print Network [OSTI]

Alkylsulfonates as Probes of Uncoupling Protein Transport Mechanism ION PAIR TRANSPORT DEMONSTRATES of Membrane Transport Biophysics, Institute of Physiology, Academy of Sciences, Prague 14220, Czech Republic is transported with the neutral ion pair, the sulfonate is able to deliver protons across the bilayer, behaving

Garlid, Keith

83

Molecular Ion Beam Transportation for Low Energy Ion Implantation  

SciTech Connect (OSTI)

A joint research and development of steady state intense boron ion sources for 100's of electron-volt ion implanters has been in progress for the past five years. Current density limitation associated with extracting and transporting low energy ion beams result in lower beam currents that in turn adversely affects the process throughput. The transport channel with electrostatic lenses for decaborane (B{sub 10}H{sub 14}) and carborane (C{sub 2}B{sub 10}H{sub 12}) ion beams transportation was developed and investigated. The significant increase of ion beam intensity at the beam transport channel output is demonstrated. The transport channel simulation, construction and experimental results of ion beam transportation are presented.

Kulevoy, T. V.; Kropachev, G. N.; Seleznev, D. N.; Yakushin, P. E.; Kuibeda, R. P.; Kozlov, A. V.; Koshelev, V. A. [Institute for Theoretical and Experimental Physics, Moscow, 117218 (Russian Federation); Hershcovitch, A.; Johnson, B. M. [Brookhaven National Laboratory, Upton, New York 11973 (United States); Gushenets, V. I.; Oks, E. M. [High Current Electronics Institute Russian Academy of Sciences, Tomsk, 634055 (Russian Federation); Polozov, S. M. [Moscow Engineering Physics Institute, Kashirskoe sh. 31, Moscow, 115409 (Russian Federation); Poole, H. J. [PVI, Oxnard, California 93031-5023 (United States)

2011-01-07T23:59:59.000Z

84

The Mutation F227I Increases the Coupling of Metal Ion Transport in DCT1*  

E-Print Network [OSTI]

stoichiometry. At pH 7 and membrane potentials of 90 to 30 mV, DCT1 transports one Fe2 ion with one H . At highThe Mutation F227I Increases the Coupling of Metal Ion Transport in DCT1* Received for publication, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel Metal ion transport

Nelson, Nathan

85

Characterization of ion selective membranes for application in reverse  

E-Print Network [OSTI]

Characterization of ion selective membranes for application in reverse electrodialysis systems I would have imagined when I started. i #12;Abstract Reverse electrodialysis (RED) is a renewable

Kjelstrup, Signe

86

Hydroxyl Ion Migration, Chemical Reactions, Water Transport and Other Effects As Optimizing Parameters In Cross-, Co- And Countercurrently Operated Membrane Cells For The Chlor/Alkali Electrolysis  

Science Journals Connector (OSTI)

A mathematical model describing a chloralkali-electrolysis in membrane cells including unusual flow pattern is presented. This paper discusses several influences like chemical reactions in the anolyte compartm...

K. H. Simmrock

1984-01-01T23:59:59.000Z

87

Unique battery with an active membrane separator having uniform physico-chemically functionalized ion channels and a method making the same  

DOE Patents [OSTI]

The invention relates to a unique battery having an active, porous membrane and method of making the same. More specifically the invention relates to a sealed battery system having a porous, metal oxide membrane with uniform, physicochemically functionalized ion channels capable of adjustable ionic interaction. The physicochemically-active porous membrane purports dual functions: an electronic insulator (separator) and a unidirectional ion-transporter (electrolyte). The electrochemical cell membrane is activated for the transport of ions by contiguous ion coordination sites on the interior two-dimensional surfaces of the trans-membrane unidirectional pores. The membrane material is designed to have physicochemical interaction with ions. Control of the extent of the interactions between the ions and the interior pore walls of the membrane and other materials, chemicals, or structures contained within the pores provides adjustability of the ionic conductivity of the membrane.

Gerald, II, Rex E. (Brookfield, IL); Ruscic, Katarina J. (Chicago, IL); Sears, Devin N. (Spruce Grove, CA); Smith, Luis J. (Natick, MA); Klingler, Robert J. (Glenview, IL); Rathke, Jerome W. (Homer Glen, IL)

2012-02-21T23:59:59.000Z

88

Self-Energy-Limited Ion Transport in Subnanometer Channels Douwe Jan Bonthuis,1  

E-Print Network [OSTI]

Self-Energy-Limited Ion Transport in Subnanometer Channels Douwe Jan Bonthuis,1 Jingshan Zhang,2 -Hemolysin (-HL) pore embedded in an insulating phospholipid membrane. An ion current of I 80 pA is reduced, and a minimum of the current as a function of C. These observations are interpreted as the result of the ion

Meller, Amit

89

Dynamics of Ion Beam Stimulated Surface Mass Transport to Nanopores David P. Hoogerheide1  

E-Print Network [OSTI]

Dynamics of Ion Beam Stimulated Surface Mass Transport to Nanopores David P. Hoogerheide1 membrane, from the substrate side, by rastering a 10-nm diameter, 50 keV gallium ion beam produced by a FEI We explore the ion beam-induced dynamics of the formation of large features at the edges of nanopores

90

Fast Transport of Mixed Ion-Chains  

E-Print Network [OSTI]

We investigate the dynamics of mixed-species ion crystals during transport between spatially distinct locations in a linear Paul trap in the diabatic regime. In a general mixed-species crystal, all degrees of freedom along the direction of transport are excited by an accelerating well, so unlike the case of same-species ions, where only the center-of-mass-mode is excited, several degrees of freedom have to be simultaneously controlled by the transport protocol. We design protocols that lead to low final excitations in the diabatic regime using invariant-based inverse-engineering for two different-species ions and also show how to extend this approach to longer mixed-species ion strings. Fast transport of mixed-species ion strings can significantly reduce the time overhead in certain architectures for scalable quantum information processing with trapped ions.

M. Palmero; R. Bowler; J. P. Gaebler; D. Leibfried; J. G. Muga

2014-06-29T23:59:59.000Z

91

ccsd-00014522,version1-5Oct2006 Co-transport-induced instability of membrane voltage in tip-growing cells  

E-Print Network [OSTI]

ccsd-00014522,version1-5Oct2006 Co-transport-induced instability of membrane voltage in tip at the same time. It is shown that these co-transporters destabilize generically the membrane voltage- tive dynamics and activity of membrane ion channels. Action potential and cardiac excitation spiral

Paris-Sud XI, Université de

92

Electrodeposition of microparticles on polarized ion exchange membranes  

SciTech Connect (OSTI)

The use of ion exchange membranes to extract microparticles from an aqueous solution is considered. The efficiency of removing negatively charged aerosil particles depends substantially on the nature of the membrane located at the anode. It has been established that besides an increase in the electric field intensity the principal factor ensuring an increase in the efficiency of purifying a solution by electrodeposition of microparticles on a membrane surface is a reduction in the flowrate relative to the membrane surface.

Verbich, S.V.; Ponomarev, M.I.; Grebenyuk, V.D.; Dukhin, S.S.

1986-11-01T23:59:59.000Z

93

Ion Conducting Membranes for Fuel Cells and other Electrochemical Devices  

Science Journals Connector (OSTI)

ion conducting membrane; fuel cell; redox-flow battery; Li ion battery; proton; hydroxide; diffusion; conductivity; nanomorphology; hydration; visco-elastic constants; phosphate; polyelectrolyte; ionomer; block-copolymer; Nafion; Aquivion ... At this stage, however, they have an immediate potential for redox-flow battery applications, as will be discussed later. ... When the flow battery is charged or discharged, an equivalent amount of ionic charge has to cross the membrane, while the ions involved in the redox process have to be efficiently separated. ...

Klaus-Dieter Kreuer

2013-11-19T23:59:59.000Z

94

Contribution of calcium-conducting channels to the transport of zinc ions Alexandre Bouron 1,2,3  

E-Print Network [OSTI]

1 Contribution of calcium-conducting channels to the transport of zinc ions Alexandre Bouron 1. The mechanisms controlling its transport through the plasma membrane are far from being completely understood in the cellular uptake of zinc. These ion channels are currently described as systems dedicated to the transport

95

Hydrogen Ion and the Activation of Electrically Excitable Membranes  

Science Journals Connector (OSTI)

... excitable cells is rather confused1. Unless one postulates complete impermeability of the cell membrane to hydrogen ions, which is improbable, or active extrusion of ... ions, which is improbable, or active extrusion of hydrogen ions, for which there is no experimental evidence, one would expect to find a ...

W. G. S. STEPHENS

1969-11-08T23:59:59.000Z

96

Correlation of Structural Differences between Nafion/Polyaniline and Nafion/Polypyrrole Composite Membranes and Observed Transport Properties  

SciTech Connect (OSTI)

Polyaniline/Nafion and polypyrrole/Nafion composite membranes, prepared by chemical polymerization, are studied by infrared and nuclear magnetic resonance spectroscopy, and scanning electron microscopy. Differences in vanadium ion diffusion through the membranes and in the membranes area specific resistance are linked to analytical observations that polyaniline and polypyrrole interact differently with Nafion. Polypyrrole, a weakly basic polymer, binds less strongly to the sulfonic acid groups of the Nafion membrane, and thus the hydrophobic polymer aggregates in the center of the Nafion channel rather than on the hydrophilic side chains of Nafion that contain sulfonic acid groups. This results in a drastically elevated membrane resistance and an only slightly decreased vanadium ion permeation compared to a Nafion membrane. Polyaniline on the other hand is a strongly basic polymer, which forms along the sidewalls of the Nafion pores and on the membrane surface, binding tightly to the sulfonic acid groups of Nafion. This leads to a more effective reduction in vanadium ion transport across the polyaniline/Nafion membranes and the increase in membrane resistance is less severe. The performance of selected polypyrrole/Nafion composite membranes is tested in a static vanadium redox cell. Increased coulombic efficiency, compared to a cell employing Nafion, further confirms the reduced vanadium ion transport through the composite membranes.

Schwenzer, Birgit; Kim, Soowhan; Vijayakumar, M.; Yang, Zhenguo; Liu, Jun

2011-04-15T23:59:59.000Z

97

On a novel rate theory for transport in narrow ion channels and its application to the study of flux optimization via geometric effects  

E-Print Network [OSTI]

On a novel rate theory for transport in narrow ion channels and its application to the study passage time to describe single-ion conduction in narrow, effectively one-dimensional membrane channels. DOI: 10.1063/1.3077205 I. INTRODUCTION Ion channels are membrane proteins which enable se- lected ions

Reingruber, Jürgen

98

Membranes for nanometer-scale mass fast transport  

DOE Patents [OSTI]

Nanoporous membranes comprising single walled, double walled, and multiwalled carbon nanotubes embedded in a matrix material were fabricated for fluid mechanics and mass transfer studies on the nanometer scale and commercial applications. Average pore size can be 2 nm to 20 nm, or seven nm or less, or two nanometers or less. The membrane can be free of large voids spanning the membrane such that transport of material such as gas or liquid occurs exclusively through the tubes. Fast fluid, vapor, and liquid transport are observed. Versatile micromachining methods can be used for membrane fabrication. A single chip can comprise multiple membranes. These membranes are a robust platform for the study of confined molecular transport, with applications in liquid and gas separations and chemical sensing including desalination, dialysis, and fabric formation.

Bakajin, Olgica (San Leandro, CA); Holt, Jason (Berkeley, CA); Noy, Aleksandr (Belmont, CA); Park, Hyung Gyu (Oakland, CA)

2011-10-18T23:59:59.000Z

99

Dynamics of a vesicle as a cell mimic: Effects of interior structure, cross-membrane transport, and interaction with filaments  

E-Print Network [OSTI]

Dynamics of a vesicle as a cell mimic: Effects of interior structure, cross-membrane transport, and interaction with filaments The biological membrane is, in essence, a thermodynamically-nonequilibrium lipid bilayer [6, 30, 34, 43, 47] with a variety of molecular motors, ion pumps, or channels residing within [19

Young, Yuan N.

100

Low temperature thermal transport in partially perforated silicon nitride membranes.  

SciTech Connect (OSTI)

The thermal transport in partially trenched silicon nitride membranes has been studied in the temperature range from 0.3 to 0.6 K, with the transition edge sensor (TES), the sole source of membrane heating. The test configuration consisted of Mo/Au TESs lithographically defined on silicon nitride membranes 1 {micro}m thick and 6 mm{sup 2} in size. Trenches with variable depth were incorporated between the TES and the silicon frame in order to manage the thermal transport. It was shown that sharp features in the membrane surface, such as trenches, significantly impede the modes of phonon transport. A nonlinear dependence of thermal resistance on trench depth was observed. Partial perforation of silicon nitride membranes to control thermal transport could be useful in fabricating mechanically robust detector devices.

Yefremenko, V.; Wang, G.; Novosad, V.; Datesman, A.; Pearson, J.; Divan, R.; Chang, C. L.; Downes, T. P.; Mcmahon, J. J.; Bleem, L. E.; Crites, A. T.; Meyer, S. S.; Carlstrom, J. E.; Univ. of Chicago

2009-05-04T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

Membrane porters of ATP-binding cassette transport systems are polyphyletic  

E-Print Network [OSTI]

in Membrane porters of ATP-binding cassette transportin Membrane porters of ATP-binding cassette transportin Membrane porters of ATP-binding cassette transport

Wang, Bin

2010-01-01T23:59:59.000Z

102

In-situ Investigation of Vanadium Ion Transport in Redox Flow Battery  

SciTech Connect (OSTI)

We will show a new method to differentiate the vanadium transport from concentration gradient and that from electric field. Flow batteries with vanadium and iron redox couples as the electro-active species were employed to investigate the transport behavior of vanadium ions in the presence of electric field. It was shown that electric field accelerated the positive-to-negative and reduced the negative-to-positive vanadium ions transport in charge process and affected the vanadium ions transport in an opposite way in discharge process. In addition, a method was designed to differentiate the concentration gradient-driven vanadium ions diffusion and electric field-driven vanadium ions migration. Simplified mathematical model was established to simulate the vanadium ions transport in real charge-discharge operation of flow battery. The concentration gradient diffusion coefficients and electric-migration coefficients of V2+, V3+, VO2+, and VO2+ across Nafion membrane were obtained by fitting the experimental data.

Luo, Qingtao; Li, Liyu; Nie, Zimin; Wang, Wei; Wei, Xiaoliang; Li, Bin; Chen, Baowei; Yang, Zhenguo

2012-06-27T23:59:59.000Z

103

Membrane Ion Channels and Ionic Hydration Energies [Abstract Only  

Science Journals Connector (OSTI)

25 November 1980 research-article Membrane Ion Channels and Ionic Hydration Energies [Abstract Only] D. T. Edmonds The Royal Society is collaborating with JSTOR to digitize, preserve, and extend access to Proceedings...

1980-01-01T23:59:59.000Z

104

Correlating Humidity-Dependent Ionically Conductive Surface Area with Transport Phenomena in Proton-Exchange Membranes  

SciTech Connect (OSTI)

The objective of this effort was to correlate the local surface ionic conductance of a Nafion? 212 proton-exchange membrane with its bulk and interfacial transport properties as a function of water content. Both macroscopic and microscopic proton conductivities were investigated at different relative humidity levels, using electrochemical impedance spectroscopy and current-sensing atomic force microscopy (CSAFM). We were able to identify small ion-conducting domains that grew with humidity at the surface of the membrane. Numerical analysis of the surface ionic conductance images recorded at various relative humidity levels helped determine the fractional area of ion-conducting active sites. A simple square-root relationship between the fractional conducting area and observed interfacial mass-transport resistance was established. Furthermore, the relationship between the bulk ionic conductivity and surface ionic conductance pattern of the Nafion? membrane was examined.

He, Qinggang; Kusoglu, Ahmet; Lucas, Ivan T.; Clark, Kyle; Weber, Adam Z.; Kostecki, Robert

2011-08-01T23:59:59.000Z

105

Interfacial Water-Transport Effects in Proton-Exchange Membranes  

SciTech Connect (OSTI)

It is well known that the proton-exchange membrane is perhaps the most critical component of a polymer-electrolyte fuel cell. Typical membranes, such as Nafion(R), require hydration to conduct efficiently and are instrumental in cell water management. Recently, evidence has been shown that these membranes might have different interfacial morphology and transport properties than in the bulk. In this paper, experimental data combined with theoretical simulations will be presented that explore the existence and impact of interfacial resistance on water transport for Nafion(R) 21x membranes. A mass-transfer coefficient for the interfacial resistance is calculated from experimental data using different permeation cells. This coefficient is shown to depend exponentially on relative humidity or water activity. The interfacial resistance does not seem to exist for liquid/membrane or membrane/membrane interfaces. The effect of the interfacial resistance is to flatten the water-content profiles within the membrane during operation. Under typical operating conditions, the resistance is on par with the water-transport resistance of the bulk membrane. Thus, the interfacial resistance can be dominant especially in thin, dry membranes and can affect overall fuel-cell performance.

Kienitz, Brian; Yamada, Haruhiko; Nonoyama, Nobuaki; Weber, Adam

2009-11-19T23:59:59.000Z

106

Topical Review Fluctuations and Fractal Noise in Biological Membranes  

E-Print Network [OSTI]

and transport of ions and molecules across biological membranes. We know that ion transport through mem- branes in electrical properties associated with cell membrane ion transport. Key words: Brownian motion -- Cell membrane elec- trical properties -- Fractals -- Gaussian noise -- Ion transport -- Nonlinear dynamics

107

Membrane permeation process for dehydration of organic liquid mixtures using sulfonated ion-exchange polyalkene membranes  

DOE Patents [OSTI]

A membrane permeation process for dehydrating a mixture of organic liquids, such as alcohols or close boiling, heat sensitive mixtures. The process comprises causing a component of the mixture to selectively sorb into one side of sulfonated ion-exchange polyalkene (e.g., polyethylene) membranes and selectively diffuse or flow therethrough, and then desorbing the component into a gas or liquid phase on the other side of the membranes.

Cabasso, Israel (131 Buckingham Ave., Syracuse, NY 13210); Korngold, Emmanuel (P.O. Box 1025, Beer-Sheva 84110, IL)

1988-01-01T23:59:59.000Z

108

Universality of Poisson Indicator and Fano Factor of Transport Event Statistics in Ion Channels and Enzyme Kinetics  

E-Print Network [OSTI]

Universality of Poisson Indicator and Fano Factor of Transport Event Statistics in Ion Channels transport has been the steady state flux in a single channel through a membrane that separates two, Cambridge, Massachusetts, 02139 United States ABSTRACT: We consider a generic stochastic model of ion

Cao, Jianshu

109

Reaction-Driven Ion Transport Membrane  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Jenny B. Tennant Jenny B. Tennant Gasification Technology Manager National Energy Technology Laboratory 3610 Collins Ferry Road P.O. Box 880 Morgantown, WV 26507-0880 304-285-4830 jenny.tennant@netl.doe.gov Susan Maley Project Manager National Energy Technology Laboratory 3610 Collins Ferry Road P.O. Box 880 Morgantown, WV 26507-0880 304-285-1321 susan.maley@netl.doe.gov David Studer Principal Investigator Air Products and Chemicals Inc.

110

NETL: Gasification - Advanced Hydrogen Transport Membranes for Coal  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Syngas Processing Systems Syngas Processing Systems Advanced Hydrogen Transport Membranes for Coal Gasification Praxair Inc. Project Number: FE0004908 Project Description Praxair is conducting research to develop hydrogen transport membrane (HTM) technology to separate carbon dioxide (CO2) and hydrogen (H2) in coal-derived syngas for IGCC applications. The project team has fabricated palladium based membranes and measured hydrogen fluxes as a function of pressure, temperature, and membrane preparation conditions. Membranes are a commercially-available technology in the chemical industry for CO2 removal and H2 purification. There is, however, no commercial application of membrane processes that aims at CO2 capture for IGCC syngas. Due to the modular nature of the membrane process, the design does not exhibit economy of scale-the cost of the system will increase linearly as the plant system scale increases making the use of commercially available membranes, for an IGCC power plant, cost prohibitive. For a membrane process to be a viable CO2 capture technology for IGCC applications, a better overall performance is required, including higher permeability, higher selectivity, and lower membrane cost.

111

Dr. Ing. /PhD / Dr.techn. Students supervised by Signe Kjelstrup 1. Torleif Holt, Transport and equilibrium properties of a cation exchange membrane (1983)  

E-Print Network [OSTI]

, (1996) 6. Magnar Ottøy, Mass and heat transfer in ion-exchange membranes (1996) 7. Belinda Flem, Peltier in the Polymer Electrolyte Membrane Fuel Cell (2007) 17. Isabella Inzoli, Coupled transports of heat and massDr. Ing. /PhD / Dr.techn. Students supervised by Signe Kjelstrup 1. Torleif Holt, Transport

Kjelstrup, Signe

112

Ion-Exchange Membranes in the Chemical Process Industry  

Science Journals Connector (OSTI)

Other applications of ion-exchange membranes are still in an early state of their development, such as the redox flow battery. ... (40) More recently, interest in electrodialysis as a flow battery has increased and will be briefly discussed in the following. ... One is based on a reversal of regular electrodialysis and is referred to as concentration flow battery,(40) and the other is based on reversal of electrodialysis with bipolar membranes and is referred to as neutralization flow battery. ...

Heiner Strathmann; Andrej Grabowski; Gerhart Eigenberger

2013-03-13T23:59:59.000Z

113

Salt Concentration Differences Alter Membrane Resistance in Reverse Electrodialysis Stacks  

E-Print Network [OSTI]

,3,4 Selective transport of ions through the membranes creates an electric potential across pairs of AEMs by changing the membrane polymer chemistry and/or membrane form factor.9-13 The ion transport properties on either side of the membrane on ion transport properties must be studied to improve our under- standing

114

High-powered pulsed-ion-beam acceleration and transport  

SciTech Connect (OSTI)

The state of research on intense ion beam acceleration and transport is reviewed. The limitations imposed on ion beam transport by space charge effects and methods available for neutralization are summarized. The general problem of ion beam neutralization in regions free of applied electric fields is treated. The physics of acceleration gaps is described. Finally, experiments on multi-stage ion acceleration are summarized.

Humphries, S. Jr.; Lockner, T.R.

1981-11-01T23:59:59.000Z

115

Ion Exchange Membrane Cathodes for Scalable Microbial Fuel Cells  

Science Journals Connector (OSTI)

Ion Exchange Membrane Cathodes for Scalable Microbial Fuel Cells ... The optimum amount of graphite fibers needed for these brush electrodes has not yet been optimized, and the cathode remains the greatest challenge for MFC designs. ... Different catalyst locations (inside versus outside) and loadings, specific surface areas, and solution chemistry (solution conductivity) were examined to optimize performance. ...

Yi Zuo; Shaoan Cheng; Bruce E. Logan

2008-08-13T23:59:59.000Z

116

Hydrogen transport membranes for dehydrogenation reactions  

DOE Patents [OSTI]

A method of converting C.sub.2 and/or higher alkanes to olefins by contacting a feedstock containing C.sub.2 and/or higher alkanes with a first surface of a metal composite membrane of a sintered homogenous mixture of an Al oxide or stabilized or partially stabilized Zr oxide ceramic powder and a metal powder of one or more of Pd, Nb, V, Zr, Ta and/or alloys or mixtures thereof. The alkanes dehydrogenate to olefins by contact with the first surface with substantially only atomic hydrogen from the dehydrogenation of the alkanes passing through the metal composite membrane. Apparatus for effecting the conversion and separation is also disclosed.

Balachandran; Uthamalingam (Hinsdale, IL)

2008-02-12T23:59:59.000Z

117

Permeation of ethylene and ethane through sulfonated polysulfones and sulfonated poly(phenylene oxide) ion exchange membranes  

SciTech Connect (OSTI)

Permeation of ethylene and ethane is sulfonated poly(phenylene oxide), sulfonated bisphenol A polyarylethersulfone and sulfonated hexafluorobisphenol A polyarylethersulfone (6F-SPS) exchanged with Ag{sup +} ions were measured as a function of degree of sulfonation, temperature and trans membrane differential pressure. The data were compared with the permeation results for these membranes in acid form and alkaline metal salt form. Membranes exchanged with Ag{sup +} ions displayed enhanced etylene permeability and ethylene-ethane separation factors. The enhancement in transport of ethylene in ion exchange membranes is apparently related to an increase in ethylene solubility affected by complexation of ethylene with immobilized Ag{sup +} ions. A substantial increase in ethylene permeation rate and separation factor was observed when the feed gas was saturated with water vapors. Enhanced permeation/separation were attributed to an increase in the mobility of silver ions in water plasticized membranes. Membranes plasticized with glycerol exhibited high ethylene permeation rate and ethylene/ethane separation factors in dry feed gas streams that were comparable with permeation rates in water plasticized membranes.

Yurkovetsky, A.; Watterson, A. [Univ. of Massachusetts, Lowell, MA (United States); Bikson, B. [Innovative Membrane Systems, Inc., Norwood, MA (United States); Kharas, G.B. [DePaul Univ., Chicago, IL (United States)

1993-12-31T23:59:59.000Z

118

MEMBRANE FUNCTION, Part 2. Passive Movement: Diffusion, Osmosis, and Gibbs-Donnan Equilibrium 1  

E-Print Network [OSTI]

such as ion gradients or sunlight. I. Passive transport Passive transport is diffusion through a membrane of the membrane. This movement is entirely by the process of diffusion (to be covered below) · ions and polar. Mechanisms of Membrane Transport There are two general modes of transport across membranes: passive transport

Prestwich, Ken

119

Operation of staged membrane oxidation reactor systems  

SciTech Connect (OSTI)

A method of operating a multi-stage ion transport membrane oxidation system. The method comprises providing a multi-stage ion transport membrane oxidation system with at least a first membrane oxidation stage and a second membrane oxidation stage, operating the ion transport membrane oxidation system at operating conditions including a characteristic temperature of the first membrane oxidation stage and a characteristic temperature of the second membrane oxidation stage; and controlling the production capacity and/or the product quality by changing the characteristic temperature of the first membrane oxidation stage and/or changing the characteristic temperature of the second membrane oxidation stage.

Repasky, John Michael

2012-10-16T23:59:59.000Z

120

Multicomponent Transport through Realistic Zeolite Membranes: Characterization & Transport in Nanoporous Networks  

SciTech Connect (OSTI)

These research studies focused on the characterization and transport for porous solids which comprise both microporosity and mesoporosity. Such materials represent membranes made from zeolites as well as for many new nanoporous solids. Several analytical sorption techniques were developed and evaluated by which these multi-dimensional porous solids could be quantitatively characterized. Notably an approach by which intact membranes could be studied was developed and applied to plate-like and tubular supported zeolitic membranes. Transport processes were studied experimentally and theoretically based on the characterization studies.

William C. Conner

2007-08-02T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Facilitated transport membrane hybrid systems for olefin purification  

SciTech Connect (OSTI)

A new membrane system has been developed by BP for refinery and chemical plant olefin purification and recovery. This facilitated transport system, coupled with distillation, offers lower capital and operating costs than conventional distillation alone. Initial results on lab scale hollow fiber devices indicate membrane flux ranging from 8.75 {times} 10{sup {minus}6} to 8 {times} 10{sup {minus}5} m{sup 3}/m{sup 2}/sec (2.5 to 23 scfd/ft{sub 2}) and selectivities from 150 to 300. Pilot plant experiments on propylene/propane and ethylene purge gas recovery over three to six months duration show membrane stability and product purity of 98.5% or greater using refinery grade propylene feed. Hybrid system optimization data for membranes and distillation indicate that using a side draw from the distillation tower provides advantages in terms of membrane area, purity of feed to the membrane, and low per-pass recovery coupled with high overall propylene recovery. Membrane performance data under various conditions are also presented. In addition to performance data, economic evaluation and energy savings are discussed.

Davis, J.C.; Valus, R.J.; Eshraghi, R.; Velikoff, A.E. [BP Research, Cleveland, OH (United States)

1993-01-01T23:59:59.000Z

122

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc., and team members, are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, ceramic, cermet (ceramic/metal), and thin film membranes were prepared, characterized, and evaluated for H{sub 2} transport. For selected ceramic membrane compositions an optimum range for transition metal doping was identified, and it was determined that highest proton conductivity occurred for two-phase ceramic materials. Furthermore, a relationship between transition metal dopant atomic number and conductivity was observed. Ambipolar conductivities of {approx}6 x 10{sup -3} S/cm were achieved for these materials, and {approx} 1-mm thick membranes generated H{sub 2} transport rates as high as 0.3 mL/min/cm{sup 2}. Cermet membranes during this quarter were found to have a maximum conductivity of 3 x 10{sup -3} S/cm, which occurred at a metal phase contact of 36 vol.%. Homogeneous dense thin films were successfully prepared by tape casting and spin coating; however, there remains an unacceptably high difference in shrinkage rates between the film and support, which led to membrane instability. Further improvements in high pressure membrane seals also were achieved during this quarter, and a maximum pressure of 100 psig was attained. CoorsTek optimized many of the processing variables relevant to manufacturing scale production of ceramic H{sub 2} transport membranes, and SCI used their expertise to deposit a range of catalysts compositions onto ceramic membrane surfaces. Finally, MTI compiled relevant information regarding Vision 21 fossil fuel plant operation parameters, which will be used as a starting point for assessing the economics of incorporating a H{sub 2} separation unit.

Shane E. Roark; Tony F. Sammells; Richard A. Mackay; Adam E. Calihman; Lyrik Y. Pitzman; Tom F. Barton; Sara L. Rolfe; Richard N. Kleiner; James E. Stephan; Mike J. Holmes; Aaron L. Wagner

2001-07-30T23:59:59.000Z

123

Ion transport through a graphene nanopore  

E-Print Network [OSTI]

Molecular dynamics simulation is utilized to investigate the ionic transport of NaCl in solution through a graphene nanopore under an applied electric field. Results show the formation of concentration polarization layers in the vicinity of the graphene sheet. The non-uniformity of the ion distribution gives rise to an electric pressure which drives vortical motions in the fluid if the electric field is sufficiently strong to overcome the influence of viscosity and thermal fluctuations. The relative importance of hydrodynamic transport and thermal fluctuations in determining the pore conductivity is investigated. A second important effect that is observed is the mass transport of water through the nanopore, with an average velocity proportional to the applied voltage and independent of the pore diameter. The flux arises as a consequence of the asymmetry in the ion distribution with respect to reflection about the plane of the graphene sheet. The accumulation of liquid molecules in the vicinity of the nanopore due to reorientation of the water dipoles by the local electric field is seen to result in a local increasein the liquid density. Results confirm that the electric conductance is proportional to the nanopore diameter for the parameter regimes that we simulated. The occurrence of fluid vortices is found to result in an increase in the effective electrical conductance.

Guohui Hu; Mao Mao; Sandip Ghosal

2013-01-09T23:59:59.000Z

124

Transport of copper ammines through a cation-exchange membrane during electrodialysis  

SciTech Connect (OSTI)

Extraction of copper ammine complexes from waste waters in electroplating technology and in production of cuprammonium fibers is an important problem and electrodialysis with ion-exchange membranes is the most promising method of solving it. The authors aim was to study transport of copper(II) ammines through a commercial cation-exchange membrane of the MK-40 type. The electrodialyzer consisted of five Plexiglas compartments separated in alternating order by MK-40 cation-exchange and MA-40 anion-exchange membranes. The authors studied the dependence of the transport of copper(II) ammine complexes on the current density at copper concentration 0.025 M in the desalination compartment and 0.15 M ammonia concentration. The experiments lead to the conclusion that electrodialysis of copper(II) ammine complexes is possible only at current densities below the limiting values and that the transport is accompanied by decrease of the formation function of the complexes both in the membrane and in the solution of the concentrate receiving compartment.

Kireeva, L.D.; Shaposhnik, V.A.; Sorokina, V.I.

1987-09-10T23:59:59.000Z

125

Engineering Development of Ceramic Membrane Reactor  

E-Print Network [OSTI]

ceramic Ion Transport Membrane (ITM) reactor system for low-cost conversion of natural gas to hydrogen;7 A Revolutionary Technology Using Ceramic Membranes Ion Transport Membranes (ITM) ­ Non-porous multiEngineering Development of Ceramic Membrane Reactor Systems for Converting Natural Gas to Hydrogen

126

VOLUME 80, NUMBER 20 P H Y S I C A L R E V I E W L E T T E R S 18 MAY 1998 Spontaneous Onset of Coherence and Energy Storage by Membrane Transporters  

E-Print Network [OSTI]

of Coherence and Energy Storage by Membrane Transporters in an RLC Electric Circuit Imre Derényi and R. Dean that oscillating or fluctuating electric fields can drive thermodynami- cally uphill transport of ions catalyzed by a molecular ion pump, the Na,K-ATPase. Theory suggests that if the transport reaction is very far from

Derényi, Imre

127

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc., and team members CoorsTek, McDermott Technology, Inc., Sued Chemie, Argonne National Laboratory and Oak Ridge National Laboratory are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, mixed proton/electron conductivity and hydrogen transport was measured as a function of metal phase content for a range of ceramic/metal (cermet) compositions. It was found that optimum performance occurred at 44 wt.% metal content for all compositions tested. Although each cermet appeared to have a continuous metal phase, it is believed that hydrogen transport increased with increasing metal content partially due to beneficial surface catalyst characteristics resulting from the metal phase. Beyond 44 wt.% there was a reduction in hydrogen transport most likely due to dilution of the proton conducting ceramic phase. Hydrogen separation rates for 1-mm thick cermet membranes were in excess of 0.1 mL/min/cm{sup 2}, which corresponded to ambipolar conductivities between 1 x 10{sup -3} and 8 x 10{sup -3} S/cm. Similar results were obtained for multiphase ceramic membranes comprised of a proton-conducting perovskite and electron conducting metal oxide. These multi-phase ceramic membranes showed only a slight improvement in hydrogen transport upon addition of a metal phase. The highest hydrogen separation rates observed this quarter were for a cermet membrane containing a hydrogen transport metal. A 1-mm thick membrane of this material achieved a hydrogen separation rate of 0.3 mL/min/cm{sup 2} at only 700 C, which increased to 0.6 mL/min/cm{sup 2} at 950 C.

Shane E. Roark; Tony F. Sammells; Richard A. Mackay; Lyrik Y. Pitzman; Alexandra Z. LaGuardia; Tom F. Barton; Sara L. Rolfe; Richard N. Kleiner; James E. Stephan; Mike J. Holmes; Aaron L. Wagner

2001-10-30T23:59:59.000Z

128

Ballistic electron transport in structured suspended semiconductor membranes  

SciTech Connect (OSTI)

We study ballistic electron transport in freely suspended AlAs/GaAs microstructures containing a high mobility two-dimensional electron gas with square lattice of antidots. We found that the magnetoresistance of the samples demonstrates commensurability oscillations both for the case of non-suspended and suspended devices. The temperature dependence of the commensurability oscillations is similar for both cases. However, the critical dc current, that suppresses these oscillations, in suspended samples is three times lower than in non-suspended ones. The observed phenomenon can be explained by peculiarities of the heat transport in membranes.

Pogosov, A. G.; Budantsev, M. V.; Zhdanov, E. Yu.; Pokhabov, D. A. [Institute of Semiconductor Physics SB RAS, Novosibirsk, Russia and Novosibirsk State University, Novosibirsk (Russian Federation)

2013-12-04T23:59:59.000Z

129

Perspective Ion Channels: From Conductance to Structure  

E-Print Network [OSTI]

membrane is an essen- tially insurmountable barrier for the flow of ions; therefore, ion transport is carried out by membrane-embedded specialized proteins in the form of transporters and ion channels a purely electrical concept to a structural dynamics view of ions in- teracting with a membrane protein

Bezanilla, Francisco

130

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc. and their team members are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, new cermet compositions were tested that demonstrated similar performance to previous materials. A 0.5-mm thick membrane achieved at H{sub 2} transport rate of 0.2 mL/min/cm{sup 2} at 950 C, which corresponded to an ambipolar conductivity of 3 x 10{sup -3} S/cm. Although these results were equivalent to those for other cermet compositions, this new composition might be useful if it demonstrates improved chemical or mechanical stability. Ceramic/ceramic composite membranes also were fabricated and tested; however, some reaction did occur between the proton- and electron-conducting phases, which likely compromised conductivity. This sample only achieved a H{sub 2} transport rate of {approx} 0.006 mL/min/cm{sup 2} and an ambipolar conductivity of {approx}4 x 10{sup -4} S/cm. Chemical stability tests were continued, and candidate ceramic membranes were found to react slightly with carbon monoxide under extreme testing conditions. A cermet compositions did not show any reaction with carbon monoxide, but a thick layer of carbon formed on the membrane surface. The most significant technical accomplishment this quarter was a new high-pressure seal composition. This material maintained a pressure differential across the membrane of {approx} 280 psi at 800 C, and is still in operation.

Shane E. Roark; Anthony F. Sammells; Richard A. Mackay; Lyrik Y. Pitzman; Thomas A. Zirbel; Thomas F. Barton; Sara L. Rolfe; U. (Balu) Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; George Farthing; Dan Rowley; Tim R. Armstrong; M.K. Ferber; Aaron L. Wagner; Jon P. Wagner

2002-07-30T23:59:59.000Z

131

Crystal Structure of a Potassium Ion Transporter TrkH  

SciTech Connect (OSTI)

The TrkH/TrkG/KtrB proteins mediate K{sup +} uptake in bacteria and probably evolved from simple K{sup +} channels by multiple gene duplications or fusions. Here we present the crystal structure of a TrkH from Vibrio parahaemolyticus. TrkH is a homodimer, and each protomer contains an ion permeation pathway. A selectivity filter, similar in architecture to those of K{sup +} channels but significantly shorter, is lined by backbone and side-chain oxygen atoms. Functional studies showed that TrkH is selective for permeation of K{sup +} and Rb{sup +} over smaller ions such as Na{sup +} or Li{sup +}. Immediately intracellular to the selectivity filter are an intramembrane loop and an arginine residue, both highly conserved, which constrict the permeation pathway. Substituting the arginine with an alanine significantly increases the rate of K{sup +} flux. These results reveal the molecular basis of K{sup +} selectivity and suggest a novel gating mechanism for this large and important family of membrane transport proteins.

Y Cao; X Jin; H Huang; M Getahun Derebe; E Levin; V Kabaleeswaran; Y Pan; M Punta; J Love; et al.

2011-12-31T23:59:59.000Z

132

Controlling polymer translocation and ion transport via charge correlations  

E-Print Network [OSTI]

We develop a correlation-corrected transport theory in order to predict ionic and polymer transport properties of membrane nanopores in physical conditions where mean-field electrostatics breaks down. The experimentally observed low KCl conductivity of open alpha-Hemolysin pores is quantitatively explained by the presence of surface polarization effects. Upon the penetration of a DNA molecule into the pore, these polarization forces combined with the electroneutrality of DNA sets a lower boundary for the ionic current, explaining the weak salt dependence of blocked pore conductivities at dilute ion concentrations. The addition of multivalent counterions into the solution results in the reversal of the polymer charge and the direction of the electroosmotic flow. With trivalent spermidine or quadrivalent spermine molecules, the charge inversion is strong enough to stop the translocation of the polymer and to reverse its motion. This mechanism can be used efficiently in translocation experiments in order to improve the accuracy of DNA sequencing by minimizing the translocation velocity of the polymer.

Sahin Buyukdagli; Tapio Ala-Nissila

2014-10-10T23:59:59.000Z

133

Reactive ion etching: Optimized diamond membrane fabrication for transmission electron microscopy  

E-Print Network [OSTI]

Commonly used preparation method for thin diamond membranes by focused ion beam (FIB) techniques results in surface damage. Here, the authors introduce an alternative method based on reactive ion etching (RIE). To compare ...

Li, Luozhou

134

Membrane vesicles: A simplified system for studying auxin transport  

SciTech Connect (OSTI)

Indoleacetic acid (IAA), the auxin responsible for regulation of growth, is transported polarly in plants. Several different models have been suggested to account for IAA transport by cells and its accumulation by membrane vesicles. One model sees diffusion of IAA driven by a pH gradient. The anion of a lipophilic weak acid like IAA or butyrate accumulates in an alkaline compartment in accord with the size of the pH gradient The accumulation of IAA may be diminished by the permeability of its lipophilic anion. This anion leak may be blocked by NPA. With anion efflux blocked, a gradient of two pH units would support an IAA accumulation of less than 50-fold at equilibrium (2) Another model sees diffusion of IAA in parallel with a saturable symport (IAA[sup [minus

Goldsmith, M.H.M.

1989-01-01T23:59:59.000Z

135

E-Print Network 3.0 - aeruginosa membrane transport Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

U. The membrane-bound electron transport system of Methanosarcina species. J. Bioenerg. Biomembr... of methanophenazine and function of phenazines in ... Source: Dietrich,...

136

Humidity-Induced Phase Transitions in Ion-Containing Block Copolymer Membranes  

E-Print Network [OSTI]

Humidity-Induced Phase Transitions in Ion-Containing Block Copolymer Membranes Moon Jeong ParkVised Manuscript ReceiVed January 3, 2008 ABSTRACT: The phase behavior of ion-containing block copolymer membranes-to-order transition is driven by an increase in the partial molar entropy of the water molecules in the ordered phase

Geissler, Phillip

137

ATP-binding cassette-like transporters are involved in the transport of lignin precursors across plasma and vacuolar membranes  

SciTech Connect (OSTI)

Lignin is a complex biopolymer derived primarily from the condensation of three monomeric precursors, the monolignols. The synthesis of monolignols occurs in the cytoplasm. To reach the cell wall where they are oxidized and polymerized, they must be transported across the cell membrane. However, the molecular mechanisms underlying the transport process are unclear. There are conflicting views about whether the transport of these precursors occurs by passive diffusion or is an energized active process; further, we know little about what chemical forms are required. Using isolated plasma and vacuolar membrane vesicles prepared from Arabidopsis, together with applying different transporter inhibitors in the assays, we examined the uptake of monolignols and their derivatives by these native membrane vesicles. We demonstrate that the transport of lignin precursors across plasmalemma and their sequestration into vacuoles are ATP-dependent primary-transport processes, involving ATP-binding cassette-like transporters. Moreover, we show that both plasma and vacuolar membrane vesicles selectively transport different forms of lignin precursors. In the presence of ATP, the inverted plasma membrane vesicles preferentially take up monolignol aglycones, whereas the vacuolar vesicles are more specific for glucoconjugates, suggesting that the different ATP-binding cassette-like transporters recognize different chemical forms in conveying them to distinct sites, and that glucosylation of monolignols is necessary for their vacuolar storage but not required for direct transport into the cell wall in Arabidopsis.

Miao, Y.C.; Liu, C.

2010-12-28T23:59:59.000Z

138

Boltzmann-Langevin transport model for heavy-ion collisions  

SciTech Connect (OSTI)

Heavy-ion collisions at intermediate energies exhibit catastrophic phenomena which requires descriptions based on stochastic transport models. First, the Boltzmann-Langevin model, which provides an example of such stochastic approaches, is briefly described. Then, a projection method for obtaining numerical solutions of the Boltzmann-Langevin equation is discussed. Finally, some applications of the model to heavy-ion collisions are presented.

Ayik, S. [Tennessee Technological Univ., Cookeville, TN (United States)]|[Joint Institute for Heavy-Ion Research, Oak Ridge, TN (United States)

1994-06-01T23:59:59.000Z

139

Effective Transport Properties Accounting for Electrochemical Reactions of Proton-Exchange Membrane Fuel Cell Catalyst Layers  

SciTech Connect (OSTI)

There has been a rapidly growing interest in three-dimensional micro-structural reconstruction of fuel cell electrodes so as to derive more accurate descriptors of the pertinent geometric and effective transport properties. Due to the limited accessibility of experiments based reconstruction techniques, such as dual-beam focused ion beam-scanning electro microscopy or micro X-Ray computed tomography, within sample micro-structures of the catalyst layers in polymer electrolyte membrane fuel cells (PEMFCs), a particle based numerical model is used in this study to reconstruct sample microstructure of the catalyst layers in PEMFCs. Then the reconstructed sample structure is converted into the computational grid using body-fitted/cut-cell based unstructured meshing technique. Finally, finite volume methods (FVM) are applied to calculate effective properties on computational sample domains.

Pharoah, Jon; Choi, Hae-Won; Chueh, Chih-Che; Harvey, David

2011-07-01T23:59:59.000Z

140

Transport coefficients of the D1-D5-P system and the membrane paradigm  

Science Journals Connector (OSTI)

I discuss a correspondence between string theory and the black hole membrane paradigm in the context of the D1-D5-P system. By using the Kubo formula, I calculate transport coefficients of the effective string model induced by two kinds of minimal scalars. Then, I show that these transport coefficients exactly agree with the corresponding membrane transport coefficients of a five-dimensional near-extremal black hole with three charges.

Yuya Sasai

2012-01-11T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Oxygen transport membrane system and method for transferring heat to catalytic/process reactors  

DOE Patents [OSTI]

A method and apparatus for producing heat used in a synthesis gas production is provided. The disclosed method and apparatus include a plurality of tubular oxygen transport membrane elements adapted to separate oxygen from an oxygen containing stream contacting the retentate side of the membrane elements. The permeated oxygen is combusted with a hydrogen containing synthesis gas stream contacting the permeate side of the tubular oxygen transport membrane elements thereby generating a reaction product stream and radiant heat. The present method and apparatus also includes at least one catalytic reactor containing a catalyst to promote the stream reforming reaction wherein the catalytic reactor is surrounded by the plurality of tubular oxygen transport membrane elements. The view factor between the catalytic reactor and the plurality of tubular oxygen transport membrane elements radiating heat to the catalytic reactor is greater than or equal to 0.5.

Kelly, Sean M; Kromer, Brian R; Litwin, Michael M; Rosen, Lee J; Christie, Gervase Maxwell; Wilson, Jamie R; Kosowski, Lawrence W; Robinson, Charles

2014-01-07T23:59:59.000Z

142

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants  

SciTech Connect (OSTI)

The objective of this project was to develop an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. A family of hydrogen separation membranes was developed including single phase mixed conducting ceramics, ceramic/ceramic composites, cermet membranes, cermet membranes containing a hydrogen permeable metal, and intermediate temperature composite layered membranes. Each membrane type had different operating parameters, advantages, and disadvantages that were documented over the course of the project. Research on these membranes progressed from ceramics to cermets to intermediate temperature composite layered membranes. During this progression performance was increased from 0.01 mL x min{sup -1} x cm{sup -2} up to 423 mL x min{sup -1} x cm{sup -2}. Eltron and team membranes not only developed each membrane type, but also membrane surface catalysis and impurity tolerance, creation of thin film membranes, alternative applications such as membrane promoted alkane dehydrogenation, demonstration of scale-up testing, and complete engineering documentation including process and mechanical considerations necessary for inclusion of Eltron membranes in a full scale integrated gasification combined cycle power plant. The results of this project directly led to a new $15 million program funded by the Department of Energy. This new project will focus exclusively on scale-up of this technology as part of the FutureGen initiative.

Carl R. Evenson; Shane E. Roark

2006-03-31T23:59:59.000Z

143

How the Membrane Protein AmtB Transports Ammonia  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

side of the membrane that recruits NH4+ and a narrower 20--long hydrophobic channel midway through the membrane that lowers the dissociation constant of NH4+, thereby forming...

144

The Dynamics of Platinum Precipitation in an Ion Exchange Membrane  

E-Print Network [OSTI]

Microscopy of polymer electrolyte membranes that have undergone operation under fuel cell conditions, have revealed a well defined band of platinum in the membrane. Here, we propose a physics based model that captures the mechanism of platinum precipitation in the polymer electrolyte membrane. While platinum is observed throughout the membrane, the preferential growth of platinum at the band of platinum is dependent on the electrochemical potential distribution in the membrane. In this paper, the location of the platinum band is calculated as a function of the gas concentration at the cathode and anode, gas diffusion coefficients and solubility constants of the gases in the membrane, which are functions of relative humidity. Under H2/N2 conditions the platinum band is located near the cathode-membrane interface, as the oxygen concentration in the cathode gas stream increases and/or the hydrogen concentration in the anode gas stream decreases, the band moves towards the anode. The model developed in this paper...

Burlatsky, S F; Atrazhev, V V; Dmitriev, D V; Kuzminyh, N Y; Erikhman, N S

2013-01-01T23:59:59.000Z

145

Interfacial Water-Transport Effects in Proton-Exchange Membranes  

E-Print Network [OSTI]

MaterialsModelinginPemFuelCells,A CombinationModelIonomerMembranesforPem?FuelCells,"ElectrochimicaActa,

Kienitz, Brian

2010-01-01T23:59:59.000Z

146

Patterned ion exchange membranes for improved power production in microbial reverse-electrodialysis cells  

E-Print Network [OSTI]

Patterned ion exchange membranes for improved power production in microbial reverse-electrodialysis August 2014 Keywords: Microbial reverse electrodialysis cell Patterned membranes Integrated spacer Internal resistance a b s t r a c t Power production in microbial reverse-electrodialysis cells (MRCs) can

147

Aquaporins comprise a family of water-transporting membrane proteins. All aquaporins are efficient water transporters, while  

E-Print Network [OSTI]

are efficient water transporters, while sustaining strict selectivity, even against protons, thereby maintaining509 Aquaporins comprise a family of water-transporting membrane proteins. All aquaporins. Further insights, particularly with respect to the dynamics of water permeation and the filter mechanism

de Groot, Bert

148

THE VITELLINE MEMBRANE OF THE UNFERTILIZED HEN'S EGG  

E-Print Network [OSTI]

membrane is charged and asymmetrical. It's directional specificity to ion transport and accompanying volumeTHE VITELLINE MEMBRANE OF THE UNFERTILIZED HEN'S EGG : ELECTROLYTE AND WATER TRANSPORT T. RYMEN J more than just the result of the membrane's ion exchange behaviour and that it may involve an enzymatic

Paris-Sud XI, Université de

149

Ion transport in sub-5-nm graphene nanopores  

SciTech Connect (OSTI)

Graphene nanopore is a promising device for single molecule sensing, including DNA bases, as its single atom thickness provides high spatial resolution. To attain high sensitivity, the size of the molecule should be comparable to the pore diameter. However, when the pore diameter approaches the size of the molecule, ion properties and dynamics may deviate from the bulk values and continuum analysis may not be accurate. In this paper, we investigate the static and dynamic properties of ions with and without an external voltage drop in sub-5-nm graphene nanopores using molecular dynamics simulations. Ion concentration in graphene nanopores sharply drops from the bulk concentration when the pore radius is smaller than 0.9nm. Ion mobility in the pore is also smaller than bulk ion mobility due to the layered liquid structure in the pore-axial direction. Our results show that a continuum analysis can be appropriate when the pore radius is larger than 0.9nm if pore conductivity is properly defined. Since many applications of graphene nanopores, such as DNA and protein sensing, involve ion transport, the results presented here will be useful not only in understanding the behavior of ion transport but also in designing bio-molecular sensors.

Suk, Myung E.; Aluru, N. R., E-mail: aluru@illinois.edu [Department of Mechanical Science and Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

2014-02-28T23:59:59.000Z

150

Reduced Fast Ion Transport Model For The Tokamak Transport Code TRANSP  

SciTech Connect (OSTI)

Fast ion transport models presently implemented in the tokamak transport code TRANSP [R. J. Hawryluk, in Physics of Plasmas Close to Thermonuclear Conditions, CEC Brussels, 1 , 19 (1980)] are not capturing important aspects of the physics associated with resonant transport caused by instabilities such as Toroidal Alfv#19;en Eigenmodes (TAEs). This work describes the implementation of a fast ion transport model consistent with the basic mechanisms of resonant mode-particle interaction. The model is formulated in terms of a probability distribution function for the particle's steps in phase space, which is consistent with the MonteCarlo approach used in TRANSP. The proposed model is based on the analysis of fast ion response to TAE modes through the ORBIT code [R. B. White et al., Phys. Fluids 27 , 2455 (1984)], but it can be generalized to higher frequency modes (e.g. Compressional and Global Alfv#19;en Eigenmodes) and to other numerical codes or theories.

Podesta,, Mario; Gorelenkova, Marina; White, Roscoe

2014-02-28T23:59:59.000Z

151

Transport properties of separating membranes MF-4SK during alkaline electrolysis of water  

Science Journals Connector (OSTI)

The transport properties of separating membranes MF-4SK are studied during electrolysis of H2O in solutions of KOH. The effective diffusion coefficients of molecules of KOH and H2O and the transfer coefficients o...

A. N. Ponomarev; Yu. L. Moskvin; S. D. Babenko

2007-03-01T23:59:59.000Z

152

E-Print Network 3.0 - alters ion transport Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

sheath thickness and ion transport... Hz and intermediate 10 MHz frequency values, the ion energy increases ... Source: Economou, Demetre J. - Department of Chemical...

153

Futile cycling at the plasma membrane: a hallmark of  

E-Print Network [OSTI]

. Transport systems catalyzing ion influx across the plasma membrane of root cells fall into two broadFutile cycling at the plasma membrane: a hallmark of low-affinity nutrient transport Dev T. Britto-affinity transport systems in the plasma membranes of root cells. In this Opinion article, we illustrate that for six

Britto, Dev T.

154

Ninth International Workshop on Plant Membrane Biology  

SciTech Connect (OSTI)

This report is a compilation of abstracts from papers which were discussed at a workshop on plant membrane biology. Topics include: plasma membrane ATP-ases; plant-environment interactions, membrane receptors; signal transduction; ion channel physiology; biophysics and molecular biology; vaculor H+ pumps; sugar carriers; membrane transport; and cellular structure and function.

Not Available

1993-12-31T23:59:59.000Z

155

Nanocomposite reverse electrodialysis (RED) ion-exchange membranes for salinity gradient power generation  

Science Journals Connector (OSTI)

Abstract Despite the important role of ion-exchange membranes (IEMs) in reverse electrodialysis (RED) systems, the current absence of proper ion-exchange membranes delays the sustainable development of the RED process for salinity gradient power generation. This research presents the preparation of a new type of organicinorganic nanocomposite cation exchange membrane and its performance characteristics. The combination of functionalized iron (III) oxide ( Fe 2 O 3 - SO 4 2 ? ) as an inorganic filler with the sulfonated poly (2,6-dimethyl-1,4-phenylene oxide) (sPPO) polymer matrix proved to have great potential for power generation by RED. The results showed that an optimal amount of Fe 2 O 3 - SO 4 2 ? (0.50.7wt%) enhanced the key electrochemical properties of the ion-exchange membranes including a permselectivity up to 87.65% and an area resistance of 0.87?cm2. The nanocomposite membrane containing 0.7wt% ( Fe 2 O 3 - SO 4 2 ? ) achieved a maximum power density (amount of power per unit membrane area) of 1.3Wm?2, which is relatively higher than that of the commercially available CSO (SelemionTM, Japan) membranes. The goal of the present work is to maximize the salinity gradient power generation by developing RED-specific nanocomposite IEMs. The results show the potential of the new design of the nanocomposite \\{IEMs\\} for viable energy generation by RED.

Jin Gi Hong; Yongsheng Chen

2014-01-01T23:59:59.000Z

156

Hybrid membrane/cryogenic separation of oxygen from air for use in the oxy-fuel process  

E-Print Network [OSTI]

and high temperature ion transport membranes. While polymeric membranes can produce oxygen enriched air of various concentrations, ion transport membranes can produce purities of close to 100%. Both membraHybrid membrane/cryogenic separation of oxygen from air for use in the oxy-fuel process Thomas

Struchtrup, Henning

157

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

During this quarter work was continued on characterizing the stability of layered composite membranes under a variety of conditions. Membrane permeation was tested up to 100 hours at constant pressure, temperature, and flow rates. In addition, design parameters were completed for a scale-up hydrogen separation demonstration unit. Evaluation of microstructure and effect of hydrogen exposure on BCY/Ni cermet mechanical properties was initiated. The fabrication of new cermets containing high permeability metals is reported and progress in the preparation of sulfur resistant catalysts is discussed. Finally, a report entitled ''Criteria for Incorporating Eltron's Hydrogen Separation Membranes into Vision 21 IGCC Systems and FutureGen Plants'' was completed.

Carl R. Evenson; Anthony F. Sammells; Richard T. Treglio; Jim Fisher; U. Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; Chandra Ratnasamy; Mahendra Sunkara; Jyothish Thangla; Clive Brereton; Warren Wolfs; James Lockhart

2005-01-28T23:59:59.000Z

158

Homogenization of the Poisson-Nernst-Planck Equations for Ion Transport in Charged Porous Media  

E-Print Network [OSTI]

Effective Poisson-Nernst-Planck (PNP) equations are derived for macroscopic ion transport in charged porous media under periodic fluid flow by an asymptotic multi-scale expansion with drift. The microscopic setting is a two-component periodic composite consisting of a dilute electrolyte continuum (described by standard PNP equations) and a continuous dielectric matrix, which is impermeable to the ions and carries a given surface charge. Four new features arise in the upscaled equations: (i) the effective ionic diffusivities and mobilities become tensors, related to the microstructure; (ii) the effective permittivity is also a tensor, depending on the electrolyte/matrix permittivity ratio and the ratio of the Debye screening length to the macroscopic length of the porous medium; (iii) the microscopic fluidic convection is replaced by a diffusion-dispersion correction in the effective diffusion tensor; and (iv) the surface charge per volume appears as a continuous "background charge density", as in classical membrane models. The coefficient tensors in the upscaled PNP equations can be calculated from periodic reference cell problems. For an insulating solid matrix, all gradients are corrected by the same tensor, and the Einstein relation holds at the macroscopic scale, which is not generally the case for a polarizable matrix, unless the permittivity and electric field are suitably defined. In the limit of thin double layers, Poisson's equation is replaced by macroscopic electroneutrality (balancing ionic and surface charges). The general form of the macroscopic PNP equations may also hold for concentrated solution theories, based on the local-density and mean-field approximations. These results have broad applicability to ion transport in porous electrodes, separators, membranes, ion-exchange resins, soils, porous rocks, and biological tissues.

Markus Schmuck; Martin Z. Bazant

2014-07-14T23:59:59.000Z

159

Ion Transport in Nanostructured Block Copolymer/Ionic Liquid Membranes  

E-Print Network [OSTI]

E. Ionic Liquids as Green Solvents: Progress and Prospectsthem attention as green solvents for synthesis and

Hoarfrost, Megan Lane

2012-01-01T23:59:59.000Z

160

Feed gas contaminant removal in ion transport membrane systems  

DOE Patents [OSTI]

Method for gas purification comprising (a) obtaining a feed gas stream containing one or more contaminants selected from the group consisting of volatile metal oxy-hydroxides, volatile metal oxides, and volatile silicon hydroxide; (b) contacting the feed gas stream with a reactive solid material in a guard bed and reacting at least a portion of the contaminants with the reactive solid material to form a solid reaction product in the guard bed; and (c) withdrawing from the guard bed a purified gas stream.

Carolan, Michael Francis (Allentown, PA); Miller, Christopher Francis (Macungie, PA)

2008-09-16T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

NETL: Gasification - Development of Ion-Transport Membrane Oxygen  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Presentations, Papers, and Publications Presentations, Papers, and Publications ITM Oxygen Development for Advanced Oxygen Supply (Oct 2011) Ted Foster, Air Products & Chemicals, Inc. presented at the Gasification Technologies Conference, San Francisco, CA Oct 9-12, 2011. ASU/IGCC Integration Strategies (Oct 2009), David McCarthy, Air Products & Chemicals, Inc., 2009 Gasification Technologies Conference, Colorado Springs, CO. ITM Oxygen: Taking the Next Step (Oct 2009), VanEric Stein, Air Products & Chemicals, Inc., 2009 Gasification Technologies Conference, Colorado Springs, CO. ITM Oxygen: Scaling Up a Low-Cost Oxygen Supply Technology (Oct 2006) Philip Armstrong, Air Products & Chemicals, Inc., 2006 Gasification Technologies Conference, Washington, D.C. ITM Oxygen: The New Oxygen Supply for the New IGCC Market (Oct 2005)

162

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc., and team members, are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, it was demonstrated that increasing the transition metal loading in a model perovskite composition resulted in an increase in hydrogen flux. Improved flux corresponded to the emergence of additional phases in the ceramic membrane, and highest flux was achieved for a composite consisting of pseudo-cubic and rhombohedral perovskite phases. A 0.9-mm thick membrane of this material generated a hydrogen flux in excess of 0.1 mL/min/cm{sup 2}, which was approximately 35 times greater than analogs with lower transition metal levels. The dopant level and crystal structure also correlated with membrane density and coefficient of thermal expansion, but did not appear to affect grain size or shape. Additionally, preliminary ceramic-metal (cermet) composite membranes demonstrated a 10-fold increase in flux relative to analogous membranes composed of only the ceramic component. The hydrogen flux for these cermet samples corresponded to a conductivity of {approx} 10{sup -3} S/cm, which was consistent with the predicted proton conductivity of the ceramic phase. Increasing the sweep gas flow rate in test reactors was found to significantly increase hydrogen flux, as well as apparent material conductivity for all samples tested. Adding humidity to the feed gas stream produced a small increase in hydrogen flux. However, the catalyst on ceramic membrane surfaces did not affect flux, which suggested that the process was membrane-diffusion limited. Representative samples and fabrication processes were evaluated on the basis of manufacturing practicality. it was determined that optimum membrane densification occurs over a very narrow temperature range for the subject ceramics. Additionally, calcination temperatures currently employed result in powders that are difficult mill and screen. These issues must be addressed to improve large-scale fabricability.

Shane E. Roark; Tony F. Sammells; Adam E. Calihman; Lyrik Y. Pitzman; Pamela M. Van Calcar; Richard A. Mackay; Tom F. Barton; Sara L. Rolfe; Richard N. Kleiner; James E. Stephan; Tim R. Armstrong; Mike J. Holmes; Aaron L. Wagner

2001-04-30T23:59:59.000Z

163

Development of an spFRET method to measure structure changes in ion exchange proteins  

E-Print Network [OSTI]

transporter, major facilitator superfamily, membrane transport, membrane transporter, OxlT, single molecule, spFRET, transport protein. Tightly coupled ion exchangers, such as the AE anion exchange systems only take place at an appreciable rate if a suitable substrate ion is bound to the transport site

Novotny, Lukas

164

Transport of Gases in Carbon Molecular Sieve Membranes by Multinuclear...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

"difficult" separations of gas mixtures such as carbon dioxide methane and ethane ethylene separations. While there are many reports on macroscopic transport properties of CMS...

165

A Complete Transport Validated Model on a Zeolite Membrane for Carbon Dioxide Permeance and Capture  

E-Print Network [OSTI]

The CO2 emissions from major industries cause serious global environment problems and their mitigation is urgently needed. The use of zeolite membranes is a very efficient way in order to capture CO2 from some flue gases. The dominant transport mechanism at low temperature andor high pressure is the diffusion through the membrane. This procedure can be divided in three steps: Adsorption of the molecules of the species in the surface of the membrane, then a driving force gives a path where the species follow inside the membrane and finally the species desorbed from the surface of the membrane. The current work is aimed at developing a simulation model for the CO2 transport through a zeolite membrane and estimate the diffusion phenomenon through a very thin membrane of 150 nm in a Wicke-Kallenbach cell. The cell is cylindrical in shape with diameter of 19 mm and consists of a retentate gas chamber, a permeate gas chamber which are separated by a cylindrical zeolite membrane. This apparatus have been modeled wit...

Gkanas, Evangelos I; Stubos, Athanasios K; Makridis, Sofoklis S

2013-01-01T23:59:59.000Z

166

Fast ion transport induced by saturated infernal mode  

SciTech Connect (OSTI)

Tokamak discharges with extended weak-shear central core are known to suffer from infernal modes when the core safety factor approaches the mode ratio. These modes can cause an outward convection of the well-passing energetic ions deposited in the core by fusion reactions and/or neutral beam injection. Convection mechanism consists in collisional slowing down of energetic ions trapped in the Doppler-precession resonance with a finite-amplitude infernal mode. Convection velocity can reach a few m/s in modern spherical tori. Possible relation of this transport with the enhanced fast ion losses in the presence of long lived modes in the MAST tokamak [I. T. Chapman et al., Nucl. Fusion 50, 045007 (2010)] is discussed.

Marchenko, V. S., E-mail: march@kinr.kiev.ua [Institute for Nuclear Research, Kyiv (Ukraine)

2014-05-15T23:59:59.000Z

167

Validation of Heavy Ion Transport Capabilities in PHITS  

SciTech Connect (OSTI)

The performance of the Monte Carlo code system PHITS is validated for heavy ion transport capabilities by performing simulations and comparing results against experimental data from heavy ion reactions of benchmark quality. These data are from measurements of secondary neutron production cross sections in reactions of Xe at 400 MeV/u with lithium and lead targets, measurements of neutrons outside of thick concrete and iron shields, and measurements of isotope yields produced in the fragmentation of a 140 MeV/u 48Ca beam on a beryllium target and on a tantalum target. A practical example that tests magnetic field capabilities is shown for a simulated 48Ca beam at 500 MeV/u striking a lithium target to produce the rare isotope 44Si, with ion transport through a fragmentation-reaction magnetic pre-separator. The results of this study show that PHITS performs reliably for the simulation of radiation fields that is necessary for designing safe, reliable and cost effective future high-powered heavy-ion accelerators in rare isotope beam facilities.

Ronningen, Reginald M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824-1321 (United States)

2007-03-19T23:59:59.000Z

168

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc., and team members CoorsTek, Sued Chemie, and Argonne National Laboratory are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying composite membrane composition and microstructure to maximize hydrogen permeation without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this quarter, a composite metal membrane based on an inexpensive hydrogen permeable metal achieved permeation rates in excess of 25 mL/min/cm{sup 2}. Preliminary attempts to incorporate this metal into a cermet were successful, and a thick cermet membrane (0.83 mm) with 40 vol.% metal phase achieved a permeation rate of nearly 0.4 mL/min/cm{sup 2}. Increasing the metal phase content and decreasing membrane thickness should significantly increase permeation, while maintaining the benefits derived from cermets. Two-phase ceramic/ceramic composite membranes had low hydrogen permeability, likely due to interdiffusion of constituents between the phases. However, these materials did demonstrate high resistance to corrosion, and might be good candidates for other composite membranes. Temperature-programmed reduction measurements indicated that model cermet materials absorbed 2.5 times as much hydrogen than the pure ceramic analogs. This characteristic, in addition to higher electron conductivity, likely explains the relatively high permeation for these cermets. Incorporation of catalysts with ceramics and cermets increased hydrogen uptake by 800 to more than 900%. Finally, new high-pressure seals were developed for cermet membranes that maintained a pressure differential of 250 psi. This result indicated that the approach for high-pressure seal development could be adapted for a range of compositions. Other items discussed in this report include mechanical testing, new proton conducting ceramics, supported thin films, and alkane to olefin conversion.

Shane E. Roark; Anthony F. Sammells; Richard A. Mackay; Lyrik Y. Pitzman; Thomas A. Zirbel; Stewart R. Schesnack; Thomas F. Barton; Sara L. Rolfe; U. (Balu) Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; Aaron L. Wagner; Jon P. Wagner

2003-01-30T23:59:59.000Z

169

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants  

SciTech Connect (OSTI)

During this quarter of the no cost extension a cermet composition referred to as EC101 containing a high permeability metal and a ceramic phase was prepared for sealing and permeability testing. Several different types of seals were developed and tested. In addition membrane surface stability was characterized.

Carl R. Evenson; Richard N. Kleiner; James E. Stephan; Frank E. Anderson

2006-01-31T23:59:59.000Z

170

NETL: Gasification - Recovery Act: Scale-Up of Hydrogen Transport Membranes  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Recovery Act: Scale-Up of Hydrogen Transport Membranes for IGCC and FutureGen Plants Recovery Act: Scale-Up of Hydrogen Transport Membranes for IGCC and FutureGen Plants Eltron Research & Development Inc. Project Number: FC26-05NT42469 Project Description The Eltron Hydrogen Transport Membrane (HTM) technology uses composite metal alloy materials to separate H2 from coal-derived syngas (a mixture of H2, CO, CO2, and steam). Carbon dioxide on the feed side of the membrane remains at high pressure and in a concentrated form suitable for capture and re-use or storage. The Eltron HTM system is an enabling technology for the production of high purity H2 and the capture of CO2 at high pressure that is applicable to future integrated gasification combined cycle (IGCC) and central station H2 production plants. These novel membranes have an operating temperature of 280 to 440 degrees Celsius (°C), which is well-matched with emerging coal gas cleaning technologies and has the potential to significantly improve the overall efficiency and process economics for future gasification-based power, fuels, and chemical production plants. Eltron's membranes can withstand differential pressures of up to 1,000 pounds per square inch gauge (psig) without structural failure, allowing for successful integration into advanced, high-pressure coal gasification plants.

171

A Novel Cl Inward-Rectifying Current in the Plasma Membrane of the Calcifying Marine Phytoplankton  

E-Print Network [OSTI]

as much as 40% of annual global carbon assimilation. Ion and nutrient transport across the plasma membrane revealed a dominant anion conductance in response to membrane hyperpolarization. Ion substitution showed conductances play an essential role in membrane voltage regulation that relates to the unique transport

Taylor, Alison

172

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

SciTech Connect (OSTI)

Eltron Research Inc., and team members CoorsTek, McDermott Technology, inc., Sued Chemie, Argonne National Laboratory, and Oak Ridge National Laboratory are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. This objective is being pursued using dense membranes based in part on Eltron-patented ceramic materials with a demonstrated ability for proton and electron conduction. The technical goals are being addressed by modifying single-phase and composite membrane composition and microstructure to maximize proton and electron conductivity without loss of material stability. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur.

Shane E. Roark; Anthony F. Sammells; Richard A. Mackay; Lyrik Y. Pitzman; Thomas A. Zirbel; Thomas F. Barton; Sara L. Rolfe; U. (Balu) Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; George Farthing; Dan Rowley; Tim R. Armstrong; R.D. Carneim; P.F. Becher; C-H. Hsueh; Aaron L. Wagner; Jon P. Wagner

2002-04-30T23:59:59.000Z

173

Membrane-Extraction Ion Mobility Spectrometry for In-Situ Detection of Chlorinated Hydrocarbons in Water  

SciTech Connect (OSTI)

Membrane-extraction ion mobility spectrometry (ME-IMS) has been developed for in-situ sampling and analysis of trace chlorinated hydrocarbons in water in a single procedure. The sampling is configured so that aqueous contaminants permeate through a spiral hollow polydimethylsiloxane (PDMS) membrane and are carried away by a vapor flow through the membrane tube. The extracted analyte flows into an atmospheric pressure chemical ionization (APCI) chamber and is analyzed in a home-made IMS analyzer. PDMS membrane is found to effectively extract chlorinated hydrocarbon solvents from liquid phase to vapor. The specialized IMS analyzer has been found to have resolutions of R=33 and 41, respectively, for negative- and positive-modes and is capable of detecting aqueous tetrachloroethylene (PCE) and trichloroethylene (TCE) as low as 80 g/L and 74 g/L in negative ion mode, respectively. The time-dependent characteristics of sampling and detection of TCE are both experimentally and theoretically studied for various concentrations, membrane lengths, and flow rates. These characteristics demonstrate that membrane-extraction IMS is feasible for the continuous monitoring of chlorinated hydrocarbons in water.

Du, Yongzhai [ORNL; Zhang, Wei [ORNL; Whitten, William B [ORNL; Li, Haiyang [ORNL; Watson, David B [ORNL; Xu, Jun [ORNL

2010-01-01T23:59:59.000Z

174

Mitochondrial potassium transport: the K+ Keith D. Garlid*, Petr Paucek  

E-Print Network [OSTI]

; Ion channel gating; Membrane transport; Volume regulation 1. Introduction The inner membrane. This means that ion traffic across the inner membrane will be very high. Moreover, the gradients driving saltReview Mitochondrial potassium transport: the K+ cycle Keith D. Garlid*, Petr Paucek Department

Garlid, Keith

175

ITM Syngas and ITM H2: Engineering Development of Ceramic Membrane Reactor Systems for  

E-Print Network [OSTI]

(U.S. DOE) and other members of the ITM Syngas/ITM H2 Team, is developing Ion Transport Membrane (ITM of the ITM membrane to oxygen ions, which diffuse through the membrane under a chemical potential gradientITM Syngas and ITM H2: Engineering Development of Ceramic Membrane Reactor Systems for Converting

176

Simulation of ion beam transport through the 400 Kv ion implanter at Michigan Ion Beam Laboratory  

SciTech Connect (OSTI)

The Michigan Ion Beam Laboratory houses a 400 kV ion implanter. An application that simulates the ion beam trajectories through the implanter from the ion source to the target was developed using the SIMION Registered-Sign code. The goals were to have a tool to develop an intuitive understanding of abstract physics phenomena and diagnose ion trajectories. Using this application, new implanter users of different fields in science quickly understand how the machine works and quickly learn to operate it. In this article we describe the implanter simulation application and compare the parameters of the implanter components obtained from the simulations with the measured ones. The overall agreement between the simulated and measured values of magnetic fields and electric potentials is {approx}10%.

Naab, F. U.; Toader, O. F.; Was, G. S. [Department of Engineering and Radiological Sciences, University of Michigan, 2355 Bonisteel Boulevard, Ann Arbor, MI 48109-2104 (United States)

2013-04-19T23:59:59.000Z

177

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants  

SciTech Connect (OSTI)

Eltron Research Inc. and team members CoorsTek, Sued Chemie, Argonne National Laboratory, and NORAM are developing an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. This project was motivated by the National Energy Technology Laboratory (NETL) Vision 21 initiative, which seeks to economically eliminate environmental concerns associated with the use of fossil fuels. Currently, this project is focusing on four basic categories of dense membranes: (1) mixed conducting ceramic/ceramic composites, (2) mixed conducting ceramic/metal (cermet) composites, (3) cermets with hydrogen permeable metals, and (4) layered composites containing hydrogen permeable alloys. Ultimately, these materials must enable hydrogen separation at practical rates under ambient and high-pressure conditions, without deactivation in the presence of feedstream components such as carbon dioxide, water, and sulfur. During this final quarter of the no cost extension several planar membranes of a cermet composition referred to as EC101 containing a high permeability metal and a ceramic phase were prepared and permeability testing was performed.

Carl R. Evenson; Richard N. Kleiner; James E. Stephan; Frank E. Anderson

2006-04-30T23:59:59.000Z

178

Bioenergetics and mechanical actuation analysis with membrane transport experiments for use in biomimetic  

E-Print Network [OSTI]

Bioenergetics and mechanical actuation analysis with membrane transport experiments for use considers the mechanics and bioenergetics of a prototype nastic structure system consisting of an array by the hydrolysis of adenosine triphosphate. After reviewing the biochemistry and bioenergetics of the active

Giurgiutiu, Victor

179

Transport Properties and Performance of Polymer Electrolyte Membranes for the Hybrid Sulfur Electrolyzer  

E-Print Network [OSTI]

not consume fossil fuels or pro- duce CO2 while producing highly pure hydrogen.1-10 Gaseous SO2 fedTransport Properties and Performance of Polymer Electrolyte Membranes for the Hybrid Sulfur and Biological Systems Department, Albuquerque, New Mexico 87123, USA c Department of Materials Science

Weidner, John W.

180

Distributed Reforming of Renewable Liquids via Water Splitting using Oxygen Transport Membrane (OTM) (Presentation)  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Reforming of Renewable Reforming of Renewable Liquids via Water Splitting using Oxygen Transport Membrane (OTM) * U. (Balu) Balachandran, T. H. Lee, C. Y. Park, and S. E. Dorris Energy Systems Division E-mail: balu@anl.gov * Work supported by the Hydrogen, Fuel Cells, and Infrastructure Technologies Program of DOE's Office of Energy Efficiency and Renewable Energy Presented at the Bio-derived Liquids Working Group (BILIWG) Meeting, Nov. 6, 2007. BILIWG Meeting, Nov. 6, 2007 2 Objective & Rationale Objective: Develop compact dense ceramic membrane reactors that enable the efficient and cost-effective production of hydrogen by reforming renewable liquid fuels using pure oxygen produced by water splitting and transported by an OTM. Rationale: Membrane technology provides the means to attack barriers to the

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
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181

Computational study of the transport mechanisms of molecules and ions in solid materials  

E-Print Network [OSTI]

electrolytes is a key element in the development of the solid lithium ion batteries. One promising material is dilithium phthalocyanine (Li2Pc), which upon self-assembly may form conducting channels for fast ion transport. Computational chemistry is employed...

Zhang, Yingchun

2009-06-02T23:59:59.000Z

182

E-Print Network 3.0 - active ion transport Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

gases,2-6 or in the active... , oscillations in the electric field are damped in the bulk plasma and ion transport is governed by ion drift... , these oscillations are damped...

183

Simulation of Membrane and Cell Culture Permeability and Transport  

E-Print Network [OSTI]

for neutral and ionized species partitioning into the membrane - only non-ionized species. Donor bulk (D) Acceptor bulk (A) D w h w D w h w k i c N k o c N ?? = ? = ?+?? ? + ? + = == i 1p pKa-pHpj 1r pH1)r(jpKa Ux N x p 1s a s j rs b s 10101 1 cc c..., Kansas, 2006 Pgp expression in human SI Mouly, S., Paine, M.F. PharmRes-20(10):1595-1598 (2003) GPEN, Kansas, 2006 Talinolol Non-linear Dose Dependence Talinolol Dose Dependence de Mey et al. J. Cardio. Pharmacol. 26(6):879 (1995) 0 200 400 600 800 1000...

Bolger, Michael

2006-10-26T23:59:59.000Z

184

The Arabidopsis Chaperone J3 Regulates the Plasma Membrane H+-ATPase through Interaction with the  

E-Print Network [OSTI]

membrane H+-ATPase (PM H+-ATPase) plays an important role in the regulation of ion and metabolite transport inactivation of the PKS5 kinase. INTRODUCTION In both plants and fungi, transport across the plasma membrane constitutes a driving force for the transport of solutes and metab- olites across the plasma membrane

Deng, Xing-Wang

185

Supporting Information for: Salt concentration differences alter membrane  

E-Print Network [OSTI]

). The membrane area available for ion transport was 11.4 cm2 . Platinum mesh electrodes that spanned the crossS1 Supporting Information for: Salt concentration differences alter membrane resistance in reverse-814-867-1847 #12;S2 Membrane resistance measurement Without a concentration difference Membrane resistance

186

Zero Emission Power Plants Using Solid Oxide Fuel Cells and Oxygen Transport Membranes  

SciTech Connect (OSTI)

Siemens Westinghouse Power Corp. (SWPC) is engaged in the development of Solid Oxide Fuel Cell stationary power systems. SWPC has combined DOE Developmental funds with commercial customer funding to establish a record of successful SOFC field demonstration power systems of increasing size. SWPC will soon deploy the first unit of a newly developed 250 kWe Combined Heat Power System. It will generate electrical power at greater than 45% electrical efficiency. The SWPC SOFC power systems are equipped to operate on lower number hydrocarbon fuels such as pipeline natural gas, which is desulfurized within the SOFC power system. Because the system operates with a relatively high electrical efficiency, the CO2 emissions, {approx}1.0 lb CO2/ kW-hr, are low. Within the SOFC module the desulfurized fuel is utilized electrochemically and oxidized below the temperature for NOx generation. Therefore the NOx and SOx emissions for the SOFC power generation system are near negligible. The byproducts of the power generation from hydrocarbon fuels that are released into the environment are CO2 and water vapor. This forward looking DOE sponsored Vision 21 program is supporting the development of methods to capture and sequester the CO2, resulting in a Zero Emission power generation system. To accomplish this, SWPC is developing a SOFC module design, to be demonstrated in operating hardware, that will maintain separation of the fuel cell anode gas, consisting of H2, CO, H2O and CO2, from the vitiated air. That anode gas, the depleted fuel stream, containing less than 18% (H2 + CO), will be directed to an Oxygen Transport Membrane (OTM) Afterburner that is being developed by Praxair, Inc.. The OTM is supplied air and the depleted fuel. The OTM will selectively transport oxygen across the membrane to oxidize the remaining H2 and CO. The water vapor is then condensed from the totally 1.5.DOC oxidized fuel stream exiting the afterburner, leaving only the CO2 in gaseous form. That CO2 can then be compressed and sequestered, resulting in a Zero Emission power generation system operating on hydrocarbon fuel that adds only water vapor to the environment. Praxair has been developing oxygen separation systems based on dense walled, mixed electronic, oxygen ion conducting ceramics for a number of years. The oxygen separation membranes find applications in syngas production, high purity oxygen production and gas purification. In the SOFC afterburner application the chemical potential difference between the high temperature SOFC depleted fuel gas and the supplied air provides the driving force for oxygen transport. This permeated oxygen subsequently combusts the residual fuel in the SOFC exhaust. A number of experiments have been carried out in which simulated SOFC depleted fuel gas compositions and air have been supplied to either side of single OTM tubes in laboratory-scale reactors. The ceramic tubes are sealed into high temperature metallic housings which precludes mixing of the simulated SOFC depleted fuel and air streams. In early tests, although complete oxidation of the residual CO and H2 in the simulated SOFC depleted fuel was achieved, membrane performance degraded over time. The source of degradation was found to be contaminants in the simulated SOFC depleted fuel stream. Following removal of the contaminants, stable membrane performance has subsequently been demonstrated. In an ongoing test, the dried afterburner exhaust composition has been found to be stable at 99.2% CO2, 0.4% N2 and 0.6%O2 after 350 hours online. Discussion of these results is presented. A test of a longer, commercial demonstration size tube was performed in the SWPC test facility. A similar contamination of the simulated SOFC depleted fuel stream occurred and the performance degraded over time. A second test is being prepared. Siemens Westinghouse and Praxair are collaborating on the preliminary design of an OTM equipped Afterburner demonstration unit. The intent is to test the afterburner in conjunction with a reduced size SOFC test module that has the anode gas separati

Shockling, Larry A.; Huang, Keqin; Gilboy, Thomas E. (Siemens Westinghouse Power Corporation); Christie, G. Maxwell; Raybold, Troy M. (Praxair, Inc.)

2001-11-06T23:59:59.000Z

187

Catalyzed CO.sub.2-transport membrane on high surface area inorganic support  

DOE Patents [OSTI]

Disclosed are membranes and methods for making the same, which membranes provide improved permeability, stability, and cost-effective manufacturability, for separating CO.sub.2 from gas streams such as flue gas streams. High CO.sub.2 permeation flux is achieved by immobilizing an ultra-thin, optionally catalyzed fluid layer onto a meso-porous modification layer on a thin, porous inorganic substrate such as a porous metallic substrate. The CO.sub.2-selective liquid fluid blocks non-selective pores, and allows for selective absorption of CO.sub.2 from gas mixtures such as flue gas mixtures and subsequent transport to the permeation side of the membrane. Carbon dioxide permeance levels are in the order of 1.0.times.10.sup.-6 mol/(m.sup.2sPa) or better. Methods for making such membranes allow commercial scale membrane manufacturing at highly cost-effective rates when compared to conventional commercial-scale CO.sub.2 separation processes and equipment for the same and such membranes are operable on an industrial use scale.

Liu, Wei

2014-05-06T23:59:59.000Z

188

Solenoidal Fields for Ion Beam Transport and Focusing  

SciTech Connect (OSTI)

In this report we calculate time-independent fields of solenoidal magnets that are suitable for ion beam transport and focusing. There are many excellent Electricity and Magnetism textbooks that present the formalism for magnetic field calculations and apply it to simple geometries [1-1], but they do not include enough relevant detail to be used for designing a charged particle transport system. This requires accurate estimates of fringe field aberrations, misaligned and tilted fields, peak fields in wire coils and iron, external fields, and more. Specialized books on magnet design, technology, and numerical computations [1-2] provide such information, and some of that is presented here. The AIP Conference Proceedings of the US Particle Accelerator Schools [1-3] contain extensive discussions of design and technology of magnets for ion beams - except for solenoids. This lack may be due to the fact that solenoids have been used primarily to transport and focus particles of relatively low momenta, e.g. electrons of less than 50 MeV and protons or H- of less than 1.0 MeV, although this situation may be changing with the commercial availability of superconducting solenoids with up to 20T bore field [1-4]. Internal reports from federal laboratories and industry treat solenoid design in detail for specific applications. The present report is intended to be a resource for the design of ion beam drivers for Inertial Fusion Energy [1-5] and Warm Dense Matter experiments [1-6], although it should also be useful for a broader range of applications. The field produced by specified currents and material magnetization can always be evaluated by solving Maxwell's equations numerically, but it is also desirable to have reasonably accurate, simple formulas for conceptual system design and fast-running beam dynamics codes, as well as for general understanding. Most of this report is devoted to such formulas, but an introduction to the Tosca{copyright} code [1-7] and some numerical results obtained with it are also presented. Details of design, fabrication, installation, and operation of magnet systems are not included; here we are concerned with calculations that precede or supplement detailed design. Mathematical derivations are presented with only a moderate number of steps. While there is no claim of originality, except for various numerical approximations and a conceptual induction module design in section 20, many of the results and discussions are not readily available elsewhere. Our primary topic is axisymmetric solenoidal systems with no magnetic materials. These simplifying features allow useful analytical calculations, which occupy sections 2-13. Deviations from axisymmetry are considered in sections 14, 15, 21, 22, and 23 and the effects of magnetic materials are treated in sections 16-20. Since magnetic aberrations are mixed with geometric aberrations in computing ion orbits, section 22 on the ion equations of motion in an arbitrary field is included.

Lee, Edward P.; Leitner, Matthaeus

2007-11-01T23:59:59.000Z

189

Effective zero-thickness model for a conductive membrane driven by an electric field Falko Ziebert,1  

E-Print Network [OSTI]

membrane models is that they do not describe electrostatic effects associated with ion transport in details cells. A membrane can be driven out of equilibrium in many ways, for instance by ion concentration. The generation of ion con- centration gradients by internal means is controlled in bio- logical cells by membrane

Bazant, Martin Z.

190

Spectroscopic in Situ Imaging of Acid Coextraction Processes in Solvent Polymeric Ion-Selective Electrode and Optode Membranes  

Science Journals Connector (OSTI)

Spectroscopic in Situ Imaging of Acid Coextraction Processes in Solvent Polymeric Ion-Selective Electrode and Optode Membranes ... 11 The optical and potentiometric responses can, therefore, be interrelated. ... 10 At high pH, on the other hand, the lower detection limit of the ISE is defined by an ion-exchange process, where H+ from the membrane is replaced by an interfering cation of the sample. ...

Ern Lindner; Titus Zwickl; Eric Bakker; Bui Thi Thu Lan; Klara Tth; Ern Pretsch

1998-02-14T23:59:59.000Z

191

Molecular modeling of the morphology and transport properties of two direct methanol fuel cell membranes: phenylated sulfonated poly(ether ether ketone ketone) versus Nafion  

SciTech Connect (OSTI)

We have used molecular dynamics simulations to examine membrane morphology and the transport of water, methanol and hydronium in phenylated sulfonated poly ether ether ketone ketone (Ph-SPEEKK) and Nafion membranes at 360 K for a range of hydration levels. At comparable hydration levels, the pore diameter is smaller, the sulfonate groups are more closely packed, the hydronium ions are more strongly bound to sulfonate groups, and the diffusion of water and hydronium is slower in Ph-SPEEKK relative to the corresponding properties in Nafion. The aromatic carbon backbone of Ph-SPEEKK is less hydrophobic than the fluorocarbon backbone of Nafion. Water network percolation occurs at a hydration level ({lambda}) of {approx}8 H{sub 2}O/SO{sub 3}{sup -}. At {lambda} = 20, water, methanol and hydronium diffusion coefficients were 1.4 x 10{sup -5}, 0.6 x 10{sup -5} and 0.2 x 10{sup -5} cm{sup 2}/s, respectively. The pore network in Ph-SPEEKK evolves dynamically and develops wide pores for {lambda} > 20, which leads to a jump in methanol crossover and ion transport. This study demonstrates the potential of aromatic membranes as low-cost challengers to Nafion for direct methanol fuel cell applications and the need to develop innovative strategies to combat methanol crossover at high hydration levels.

Devanathan, Ramaswami; Idupulapati, Nagesh B.; Dupuis, Michel

2012-08-14T23:59:59.000Z

192

Transport Membrane Condenser for Water and Energy Recovery from Power Plant Flue Gas  

SciTech Connect (OSTI)

The new waste heat and water recovery technology based on a nanoporous ceramic membrane vapor separation mechanism has been developed for power plant flue gas application. The recovered water vapor and its latent heat from the flue gas can increase the power plant boiler efficiency and reduce water consumption. This report describes the development of the Transport Membrane Condenser (TMC) technology in details for power plant flue gas application. The two-stage TMC design can achieve maximum heat and water recovery based on practical power plant flue gas and cooling water stream conditions. And the report includes: Two-stage TMC water and heat recovery system design based on potential host power plant coal fired flue gas conditions; Membrane performance optimization process based on the flue gas conditions, heat sink conditions, and water and heat transport rate requirement; Pilot-Scale Unit design, fabrication and performance validation test results. Laboratory test results showed the TMC system can exact significant amount of vapor and heat from the flue gases. The recovered water has been tested and proved of good quality, and the impact of SO{sub 2} in the flue gas on the membrane has been evaluated. The TMC pilot-scale system has been field tested with a slip stream of flue gas in a power plant to prove its long term real world operation performance. A TMC scale-up design approach has been investigated and an economic analysis of applying the technology has been performed.

Dexin Wang

2012-03-31T23:59:59.000Z

193

Energy use by biological protein transport pathways  

E-Print Network [OSTI]

residing within energy-conserving membranes use transmembrane ion gradients to drive substrate transport receptors impart specificity to a targeting route, and transport across or into the membrane is typicallyEnergy use by biological protein transport pathways Nathan N. Alder1 and Steven M. Theg2 1

Economou, Tassos

194

Tuning heat transport in trapped-ion chains across a structural phase transition  

E-Print Network [OSTI]

We explore heat transport across an ion Coulomb crystal beyond the harmonic regime by tuning it across the structural phase transition between the linear and zigzag configurations. This demonstrates that the control of the spatial ion distribution by varying the trapping frequencies renders ion Coulomb crystals an ideal test-bed to study heat transport properties in finite open system of tunable non-linearities.

Antonia Ruiz; Daniel Alonso; Martin B. Plenio; Adolfo del Campo

2014-01-21T23:59:59.000Z

195

RESEARCH PAPER The face value of ion fluxes: the challenge of determining  

E-Print Network [OSTI]

is the membrane-transport parameter of greatest interest to most researchers in the field of plant ion transport physiology. Key words: Barley, cellular ion exchange, efflux, high-affinity transport, influx, low-affinity transport, potassium. Introduction The unidirectional influx of nutrient ions into the plant cell

Britto, Dev T.

196

Transport in JET H-mode Plasmas with Beam and Ion Cyclotron Heating  

SciTech Connect (OSTI)

Ion Cyclotron (IC) Range of Frequency waves and neutral beam (NB) injection are planned for heating in ITER and other future tokamaks. It is important to understand transport in plasmas with NB and IC to plan, predict, and improve transport and confinement. Transport predictions require simulations of the heating profiles, and for this, accurate modeling of the IC and NB heating is needed.

R.V. Budny, et. al.

2012-07-13T23:59:59.000Z

197

Application of various membranes to remove NOM typically occurring in Korea with respect to DBP, AOC and transport parameters  

Science Journals Connector (OSTI)

Bench- and pilot-scale membrane tests were performed to remove natural organic matter (NOM) originating from Paldang Lake in Korea. Membrane performance was demonstrated in terms of DOC, biodegradable organic carbon (BDOC), assimilable organic carbon (AOC), and transport parameters. Various membranes such as reverse osmosis (RO), nanofiltration (NF) and ultrafiltration (UF) were investigated for this study. Four different NF membranes were selected for pilot-scale filtration testing and investigated in terms of both flux decline and DOC removal. To demonstrate the effect of temperature on the source water seasonally, the flux of membranes was measured with pure water at different temperatures ranging from 25 to 7C. Coagulation/sedimentation treated water was used as feed water without removing residual chlorine; related plants were located at the Suji water treatment plant of Yongin City. To investigate more rigorously the organic fouling for various NF membranes, mass transport behaviors of organic matter solutes were evaluated by an irreversible thermodynamic model. The pore sizes of the NF membranes tested in the pilot slightly increased due to the oxidation of the polymer structure of the membranes from residual chlorine during the 4-month tests. Periodic chemical cleaning with a caustic solution was made to prevent accumulation of foulants on the membrane surface. The NF membranes exhibited stable efficiencies in terms of DOC and AOC removal during the test for 4 months.

Noeon Park; Boksoon Kwon; Minjeong Sun; Hyowon Ahn; Chunghwan Kim; Changho Kwoak; Dongju Lee; Seonha Chae; Hoon Hyung; Jaeweon Cho

2005-01-01T23:59:59.000Z

198

Understanding and engineering ion transport in conducting polymers.  

E-Print Network [OSTI]

??Many organic electronic and bioelectronics devices rely on mixed (electronic and ionic) transport within a single organic layer. Although electronic transport in these materials is (more)

Stavrinidou, Eleni

2013-01-01T23:59:59.000Z

199

Mathematical modeling of liquid/liquid hollow fiber membrane contactor accounting for interfacial transport phenomena: Extraction of lanthanides as a surrogate for actinides  

SciTech Connect (OSTI)

This report is divided into two parts. The second part is divided into the following sections: experimental protocol; modeling the hollow fiber extractor using film theory; Graetz model of the hollow fiber membrane process; fundamental diffusive-kinetic model; and diffusive liquid membrane device-a rigorous model. The first part is divided into: membrane and membrane process-a concept; metal extraction; kinetics of metal extraction; modeling the membrane contactor; and interfacial phenomenon-boundary conditions-applied to membrane transport.

Rogers, J.D.

1994-08-04T23:59:59.000Z

200

The RCK Domain of the KtrAB K+ Transporter: Multiple Conformations  

E-Print Network [OSTI]

that is propagated to the membrane-bound protein, leading to ion transport (Jiang et al., 2002a; Roosild et al., 2002 transporter is a complex of the KtrB membrane protein and KtrA, an RCK do- main. RCK domains regulate eukaryotic and prokaryotic membrane proteins involved in K+ transport. Conflicting functional models have

Gruner, Sol M.

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Water uptake, ionic conductivity and swelling properties of anion-exchange membrane  

E-Print Network [OSTI]

occurs with negative excess volume of mixing. Percolative nature of the ion transport has been is reduced at the cathode to produce OH? , which transports through the anion-exchange membrane (AEM membrane, AEM can conduct ions only in the presence of water. In addition, water is one of the reactants

202

DEVELOPMENT OF PROTOTYPE TITANATE ION EXCHANGE LOADED MEMBRANES FOR STRONTIUM, CESIUM AND ACTINIDE DECONTAMINATION FROM AQUEOUS MEDIA  

SciTech Connect (OSTI)

We have successfully incorporated high surface area particles of titanate ion exchange materials (monosodium titanate and crystalline silicotitanate) with acceptable particle size distribution into porous and inert support membrane fibrils consisting of polytetrafluoroethylene (Teflon{reg_sign}), polyethylene and cellulose materials. The resulting membrane sheets, under laboratory conditions, were used to evaluate the removal of surrogate radioactive materials for cesium-137 and strontium-90 from high caustic nuclear waste simulants. These membrane supports met the nominal requirement for nonchemical interaction with the embedded ion exchange materials and were porous enough to allow sufficient liquid flow. Some of this 47-mm size stamped out prototype titanium impregnated ion exchange membrane discs was found to remove more than 96% of dissolved cesium-133 and strontium-88 from a caustic nuclear waste salt simulants. Since in traditional ion exchange based column technology monosodium titanate (MST) is known to have great affinity for the sorbing of other actinides like plutonium, neptunium and even uranium, we expect that the MST-based membranes developed here, although not directly evaluated for uptake of these three actinides because of costs associated with working with actinides which do not have 'true' experimental surrogates, would also show significant affinity for these actinides in aqueous media. It was also observed that crystalline silicotitanate impregnated polytetrafluoroethylene or polyethylene membranes became less selective and sorbed both cesium and strontium from the caustic aqueous salt simulants.

Oji, L; Keisha Martin, K; David Hobbs, D

2008-05-30T23:59:59.000Z

203

Direct numerical simulation of electroconvective instability and hysteretic current-voltage response of a permselective membrane  

E-Print Network [OSTI]

We present a systematic, multiscale, fully detailed numerical modeling for dynamics of fluid flow and ion transport covering Ohmic, limiting, and overlimiting current regimes in conductance of ion-selective membrane. By ...

Pham, Van Sang

204

Two-phase flow and transport in the air cathode of proton exchange membrane fuel cells  

SciTech Connect (OSTI)

Two-phase flow and transport of reactants and products in the air cathode of proton exchange membrane (PEM) fuel cells is studied analytically and numerically. Four regimes of water distribution and transport are classified by defining three threshold current densities and a maximum current density. They correspond to first appearance of liquid water at the membrane/cathode interface, extension of the gas-liquid two-phase zone to the cathode/channel interface, saturated moist air exiting the gas channel, and complete consumption of oxygen by the electrochemical reaction. When the cell operates above the first threshold current density, liquid water appears and a two-phase zone forms within the porous cathode. A two-phase, multi-component mixture model in conjunction with a finite-volume-based computational fluid dynamics (CFD) technique is applied to simulate the cathode operation in this regime. The model is able to handle the situation where a single-phase region co-exists with a two-phase zone in the air cathode. For the first time, the polarization curve as well as water and oxygen concentration distributions encompassing both single- and two-phase regimes of the air cathode are presented. Capillary action is found to be the dominant mechanism for water transport inside the two-phase zone. The liquid water saturation within the cathode is predicted to reach 6.3% at 1.4 A/cm{sup 2}.

WANG,Z.H.; WANG,C.Y.; CHEN,KEN S.

2000-03-20T23:59:59.000Z

205

Neutron Reflectivity Study of Lipid Membranes Assembled on Ordered Nanocomposite and Nanoporous Silica Thin  

E-Print Network [OSTI]

moleculestrappedwithinthenanocompositethinfilmmay be used to detect trans-membrane transport (e.g., ion channel function). Furthermore, the ability in facilitating molecular transport across the membrane plane. In this regard, the use of ultrathin polymericNeutron Reflectivity Study of Lipid Membranes Assembled on Ordered Nanocomposite and Nanoporous

Parikh, Atul N.

206

Continuum electromechanical modeling of protein-membrane interactions Y. C. Zhou*  

E-Print Network [OSTI]

and topological transformations of membrane are crucial steps in numerous transport and signaling processes of cells, includ- ing cell migration, membrane trafficking, and ion conduc- tance 1­3 . There are various sorting complex required for transport III ESCRT III in- duced membrane budding or protrusion 5

Lu, Benzhuo

207

Membrane vesicles: A simplified system for studying auxin transport. Final technical report  

SciTech Connect (OSTI)

Indoleacetic acid (IAA), the auxin responsible for regulation of growth, is transported polarly in plants. Several different models have been suggested to account for IAA transport by cells and its accumulation by membrane vesicles. One model sees diffusion of IAA driven by a pH gradient. The anion of a lipophilic weak acid like IAA or butyrate accumulates in an alkaline compartment in accord with the size of the pH gradient The accumulation of IAA may be diminished by the permeability of its lipophilic anion. This anion leak may be blocked by NPA. With anion efflux blocked, a gradient of two pH units would support an IAA accumulation of less than 50-fold at equilibrium (2) Another model sees diffusion of IAA in parallel with a saturable symport (IAA{sup {minus}} + nH{sup +}), driven by both the pH gradient and membrane voltage. Such a symport should be highly accumulative, however, with a lipophilic weak acid such as IAA, net diffusive efflux of IAAH whenever IAAHI{sub i} > IAAH{sub o} would constitute a leak. (3) A third model sees a pH change driven IAA uptake and saturable symport enhanced by internal binding sites. Following pH gradient-driven accumulation of IAA, the anion may bind to an intravesicular site, permitting further uptake of IAA. NPA, by blocking anion efflux, enhances this binding. We have reported that membrane vesicles isolated from actively growing plant tissues are a good system for studying the mechanisms involved in the transport and accumulation of auxin.

Goldsmith, M.H.M.

1989-12-31T23:59:59.000Z

208

Tuning heat transport in trapped-ion chains across a structural phase transition  

Science Journals Connector (OSTI)

We analyze the heat transport in an ion chain that is confined in a strongly anisotropic Paul trap. To drive a heat current across the chain different pairs of counterpropagating laser beams are applied to the ions on the edges. The lasers behave as heat reservoirs operating at different temperatures, and a nonequilibrium heat flow can be sustained. The control of the spatial distribution of the ions in the chain by variation of the trapping frequencies makes ion chains an ideal testbed to study heat transport properties in finite open systems of low dimensionality with tunable nonlinearities. We explore heat transport across a structural phase transition between the linear and zigzag configurations, identifying the condition for optimal heat transport.

A. Ruiz; D. Alonso; M. B. Plenio; A. del Campo

2014-06-13T23:59:59.000Z

209

Generation, transport and focusing of high-brightness heavy ion beams  

E-Print Network [OSTI]

The Neutralized Transport Experiment (NTX) has been built at the Heavy Ion Fusion Virtual National Laboratory. NTX is the first successful integrated beam system experiment that explores various physical phenomena, and ...

Henestroza, Enrique

2006-01-01T23:59:59.000Z

210

Membrane-based processes for sustainable power generation using water  

Science Journals Connector (OSTI)

... 18 GW of salinity-gradient power. Although 800 GW of power is currently obtained from hydroelectric processes globally, salinity-gradient energy remains a large and untapped resource. Capturing this energy ... not ions through the membranes to produce pressurized water that generates electricity using mechanical turbines. RED uses membranes for ion but not water transport, and the electrical ...

Bruce E. Logan; Menachem Elimelech

2012-08-15T23:59:59.000Z

211

Staged membrane oxidation reactor system  

DOE Patents [OSTI]

Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

2012-09-11T23:59:59.000Z

212

Staged membrane oxidation reactor system  

DOE Patents [OSTI]

Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

2014-05-20T23:59:59.000Z

213

Staged membrane oxidation reactor system  

DOE Patents [OSTI]

Ion transport membrane oxidation system comprising (a) two or more membrane oxidation stages, each stage comprising a reactant zone, an oxidant zone, one or more ion transport membranes separating the reactant zone from the oxidant zone, a reactant gas inlet region, a reactant gas outlet region, an oxidant gas inlet region, and an oxidant gas outlet region; (b) an interstage reactant gas flow path disposed between each pair of membrane oxidation stages and adapted to place the reactant gas outlet region of a first stage of the pair in flow communication with the reactant gas inlet region of a second stage of the pair; and (c) one or more reactant interstage feed gas lines, each line being in flow communication with any interstage reactant gas flow path or with the reactant zone of any membrane oxidation stage receiving interstage reactant gas.

Repasky, John Michael; Carolan, Michael Francis; Stein, VanEric Edward; Chen, Christopher Ming-Poh

2013-04-16T23:59:59.000Z

214

A Novel Ion selective Polymeric Membrane Sensor for Determining Thallium(I) With High Selectivity  

Science Journals Connector (OSTI)

Thallium is a toxic metal that introduced into the environment mainly as a waste from the production of zinc, cadmium, and lead and by combustion of coal. Thallium causes gastrointestinal irritation and nerve damage when people are exposed to it for relatively short period of time. For long term, thallium has the potential to cause the following effects: change in blood chemistry, damage to liver, kidney, intestinal and testicular tissue, and hair loss. In this work a membrane was prepared by use of 4'nitrobenzo 18crown6 (4'NB18C6) as an ion carrier, polyvinylchloride (PVC) as a matrix, and diocthylphetalate (DOP) as a plasticizer for making an ion selective electrode for measurement of Tl+ cation in solutions. The amount of 4'-nitrobenzo-18C6 and polyvinylchloride were optimized in the preparation of the membrane. The response of the electrode was Nernstian within the concentration range 1.0 ? 10?8 to 1.0 ? 10?1M. This sensor displays a drift in Nernstian response for this cation with increasing the amount of ionophore and decreasing the amount of polyvinylchloride.The results of potentiometric measurements showed that, this electrode also responses to Cu2+ Ni2+ and Pb2+ cations, but the electrode has a wider dynamic range and a lower detection limit to Tl+ cation. The effects of various parameters such as pH, different cations interferences, effect of the amount of ionophore and polyvinylchloride and time on response of the coated ion selective electrode were investigated. Finally the constructed electrode was used in complexometric and precipitation titrations of Tl+ cation with EDTA and KBr, respectively. The response of the fabricated electrode at concentration range from 1.0 ? 10?8 to 1.0 ? 10?1M is linear with a Nernstian slope of 57.27 mV.

Anuar Kassim; Majid Rezayi; Saeid Ahmadzadeh; Gholamhossein Rounaghi; Masoomeh Mohajeri; Noor Azah Yusof; Tan Wee Tee; Lee Yook Heng; Abd Halim Abdullah

2011-01-01T23:59:59.000Z

215

Production of permeable cellulose triacetate membranes  

DOE Patents [OSTI]

A phase inversion process for the preparation of cellulose triacetate (CTA) and regenerated cellulose membranes is disclosed. Such membranes are useful as supports for liquid membranes in facilitated transport processes, as microfiltration membranes, as dialysis or ultrafiltration membranes, and for the preparation of ion-selective electrodes. The process comprises the steps of preparing a casting solution of CTA in a solvent comprising a mixture of cyclohexanone and methylene chloride, casting a film from the casting solution, and immersing the cast film in a methanol bath. The resulting CTA membrane may then be hydrolyzed to regenerated cellulose using conventional techniques.

Johnson, B.M.

1986-12-23T23:59:59.000Z

216

Production of permeable cellulose triacetate membranes  

DOE Patents [OSTI]

A phase inversion process for the preparation of cellulose triacetate (CTA) and regenerated cellulose membranes is disclosed. Such membranes are useful as supports for liquid membranes in facilitated transport processes, as microfiltration membranes, as dialysis or ultrafiltration membranes, and for the preparation of ion-selective electrodes. The process comprises the steps of preparing a casting solution of CTA in a solvent comprising a mixture of cyclohexanone and methylene chloride, casting a film from the casting solution, and immersing the cast film in a methanol bath. The resulting CTA membrane may then be hydrolyzed to regenerated cellulose using conventional techniques.

Johnson, Bruce M. (Bend, OR)

1986-01-01T23:59:59.000Z

217

Mechanism of Ion Transport in Solid Polymer Electrolytes Dr. Janna K. Maranas  

E-Print Network [OSTI]

. of Chemical Engineering, Penn State College of Engineering Lithium ion batteries used in cell phonesMechanism of Ion Transport in Solid Polymer Electrolytes Dr. Janna K. Maranas Associate Professor Dept. of Chemical Engineering, Penn State College of Engineering Kan-Ju Lin Ph.D. Candidate, Dept

Bjørnstad, Ottar Nordal

218

Ideal Desalination through Graphyne-4 Membrane: Nanopores for Quantized Water Transport  

E-Print Network [OSTI]

Graphyne-4 sheet exhibits promising potential for nanoscale desalination to achieve both high water permeability and salt rejection rate. Extensive molecular dynamics simulations on pore-size effects suggest that graphyne-4, with 4 acetylene bonds between two adjacent phenyl rings, has the best performance with 100% salt rejection and an unprecedented water permeability, to our knowledge, of ~13L/cm2/day/MPa, about 10 times higher than the state-of-the-art nanoporous graphene reported previously (Nano Lett.s 2012, 12, 3602-3608). In addition, the membrane entails very low energy consumption for producing 1m3 of fresh water, i.e., 3.6e-3 kWh/m3, three orders of magnitude less than the prevailing commercial membranes based on reverse osmosis. Water flow rate across the graphyne-4 sheet exhibits intriguing nonlinear dependence on the pore size owing to the quantized nature of water flow at the nanoscale. Such novel transport behavior has important implications to the design of highly effective and efficient desalination membranes.

Chongqin Zhu; Hui Li; Xiao Cheng Zeng; Sheng Meng

2013-06-30T23:59:59.000Z

219

Charged Amino Acids (R83, E567, D617, E625, R669, and K678) of CusA Are Required for Metal Ion Transport in the Cus Efflux System  

SciTech Connect (OSTI)

Gram-negative bacteria expel various toxic chemicals via tripartite efflux pumps belonging to the resistance-nodulation-cell division superfamily. These pumps span both the inner and outer membranes of the cell. The three components of these tripartite systems are an inner-membrane, substrate-binding transporter (or pump); a periplasmic membrane fusion protein (or adaptor); and an outer-membrane-anchored channel. These three efflux proteins interact in the periplasmic space to form the three-part complexes. We previously presented the crystal structures of both the inner-membrane transporter CusA and membrane fusion protein CusB of the CusCBA tripartite efflux system from Escherichia coli. We also described the co-crystal structure of the CusBA adaptor-transporter, revealing that the trimeric CusA efflux pump assembles with six CusB protein molecules to form the complex CusB{sub 6}-CusA{sub 3}. We here report three different conformers of the crystal structures of CusBA-Cu(I), suggesting a mechanism on how Cu(I) binding initiates a sequence of conformational transitions in the transport cycle. Genetic analysis and transport assays indicate that charged residues, in addition to the methionine pairs and clusters, are essential for extruding metal ions out of the cell.

Su, Chih-Chia; Long, Feng; Lei, Hsiang-Ting; Reddy Bolla, Jani; Do, Sylvia V.; Rajashankar, Kanagalaghatta R.; Yu, Edward W. (Cornell); (Iowa State)

2012-10-23T23:59:59.000Z

220

Metal nanoparticles in catalytic polymer membranes and ion-exchange systems for advanced purification of water from molecular oxygen  

Science Journals Connector (OSTI)

Methods of synthesis of metal nanoparticles and metal/polymer nanocomposites including ion-exchange materials are considered. The effect of the composition and size of nanoparticles on their catalytic activity is analyzed. Attention is focused on the composites used in catalytic processes, namely, catalytic membranes and ion-exchange systems. The problems associated with the removal of dissolved oxygen from water by means of such composites are discussed. The bibliography includes 225 references.

V V Volkov; T A Kravchenko; Vyacheslav I Roldughin

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Evidence for a dynamic and transient pathway through the TAT protein transport machinery  

E-Print Network [OSTI]

, University of Florida, Gainesville FL, USA Tat systems transport completely folded proteins across ion Categories: membranes & transport; proteins Keywords: chloroplasts; protein transport; thylakoid; trans transport machinery in thylakoids (called cpTat) consists of three membrane proteins; Tha4, Hcf106, and cp

222

J. Membrane Biol. 4,179-192 (1971) 9 by Springer-Verlag New York Inc. 1971  

E-Print Network [OSTI]

antibiotics increase the ion permeability of biological membranes have been carried out on artificial model the possibility that they may serve as model systems for active transport across biological membranes. Moore and Pressman (1964) discovered the influence of valinomycin on the ion transport across the mitochondrial

Junge, Wolfgang

223

Ann. N.Y. Acad. Sci. 986: 116126 (2003). 2003 New York Academy of Sciences. Ion Occlusion/Deocclusion Partial Reactions in  

E-Print Network [OSTI]

-type ion-motive ATPases, transported ions approach their binding sites from one membrane surface, become an alternating-gate transport mechanism, in which the pump acts like an ion channel with two gates that open ion transport, the probability of the pump's two gates being open simultaneously must be extremely low

Gadsby, David

224

Na K -pump ligands modulate gating of palytoxin-induced ion channels  

E-Print Network [OSTI]

proteins that mediate transport of ions across cell membranes, they traditionally have been viewed as very to the extracellular surface. The 3Na 2K -exchange transport cycle is completed when two extracellular K ions bind ensure the vectorial nature of net transport. The occluded-ion conformations, with binding sites

Gadsby, David

225

Membrane formation by preferential solvation of ions in mixture of water, 3-methylpyridine, and sodium tetraphenylborate  

SciTech Connect (OSTI)

The structure and dynamics of a ternary system composed of deuterium oxide (D{sub 2}O), 3-methylpyridine (3MP), and sodium tetraphenylborate (NaBPh{sub 4}) are investigated by means of small-angle neutron scattering (SANS) and neutron spin echo (NSE) techniques. In the SANS experiments, a structural phase transition is confirmed between a disordered-phase and an ordered-lamellar-phase upon variation of the composition and/or temperature of the mixture. The characteristic lengths of the structures is on the sub-micrometer scale. A dispersion relation of the structure is measured through NSE experiments, which shows that the relaxation rate follows a cubic relation with momentum transfer. This implies that the dynamics of the system are determined predominantly by membrane fluctuations. The present results indicate that 3MP-rich domains are microscopically separated from bulk water in the presence of NaBPh{sub 4}, and that the layers behave as membranes. These results are interpreted that preferential solvation of salt in each solvent induces a microphase separation between the solvents, and the periodic structure of 3MP-rich domains is stabilized by the long-range electrostatic interaction arising from Na{sup +} ions in D{sub 2}O-rich domains.

Sadakane, Koichiro, E-mail: sadakane@fc.ritsumei.ac.jp [Department of Physics, Ritsumeikan University, Noji-Higashi 1-1-1, Kusatsu 525-8577 (Japan)] [Department of Physics, Ritsumeikan University, Noji-Higashi 1-1-1, Kusatsu 525-8577 (Japan); Nagao, Michihiro [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102 (United States) [NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6102 (United States); Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana 47408-1398 (United States); Endo, Hitoshi; Seto, Hideki [KENS and CMRC, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801 (Japan)] [KENS and CMRC, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba 305-0801 (Japan)

2013-12-21T23:59:59.000Z

226

Equivalence of trans paths in ion channels Juan Alvarez*  

E-Print Network [OSTI]

explore stochastic models for the study of ion transport in biological cells. Analysis of these models explains and explores an interesting feature of ion transport observed by biophysicists. Namely the interior and exterior of the cell. The membrane is a lipid bilayer that is essentially impermeable to ions

Hajek, Bruce

227

Transport and Failure in Li-ion Batteries | Stanford Synchrotron...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Li-ion Batteries Monday, February 13, 2012 - 1:30pm SSRL Conference Room 137-322 Stephen J. Harris, General Motors R&D While battery performance is well predicted by the...

228

Ion transport and structure of layer-by-layer assemblies  

E-Print Network [OSTI]

Layer-by-layer (LbL) films of various architectures were examined as potential solid state electrolytes for electrochemical systems (e.g. batteries and fuel cells). The relationship between materials properties and ion ...

Lutkenhaus, Jodie Lee

2007-01-01T23:59:59.000Z

229

Transport Membrane Condenser for Water and Energy Recovery from Power Plant Flue Gas  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Dexin Wang Dexin Wang Principal Investigator Gas Technology Institute 1700 South Mount Prospect Rd Des Plaines, Il 60018 847-768-0533 dexin.wang@gastechnology.org TransporT MeMbrane Condenser for WaTer and energy reCovery froM poWer planT flue gas proMIs/projeCT no.: nT0005350 Background One area of the U.S. Department of Energy's (DOE) Innovations for Existing Plants (IEP) Program's research is being performed to develop advanced technologies to reuse power plant cooling water and associated waste heat and to investigate methods to recover water from power plant flue gas. Considering the quantity of water withdrawn and consumed by power plants, any recovery or reuse of this water can significantly reduce the plant's water requirements. Coal occurs naturally with water present (3-60 weight %), and the combustion

230

ZERO EMISSION POWER PLANTS USING SOLID OXIDE FUEL CELLS AND OXYGEN TRANSPORT MEMBRANES  

SciTech Connect (OSTI)

Over 16,700 hours of operational experience was gained for the Oxygen Transport Membrane (OTM) elements of the proposed SOFC/OTM zero-emission power generation concept. It was repeatedly demonstrated that OTMs with no additional oxidation catalysts were able to completely oxidize the remaining depleted fuel in a simulated SOFC anode exhaust at an O{sub 2} flux that met initial targets. In such cases, neither residual CO nor H{sub 2} were detected to the limits of the gas chromatograph (<10 ppm). Dried OTM afterburner exhaust streams contained up to 99.5% CO{sub 2}. Oxygen flux through modified OTMs was double or even triple that of the standard OTMs used for the majority of testing purposes. Both the standard and modified membranes in laboratory-scale and demonstration-sized formats exhibited stable performance over extended periods (2300 to 3500 hours or 3 to 5 months). Reactor contaminants, were determined to negatively impact OTM performance stability. A method of preventing OTM performance degradation was developed and proven to be effective. Information concerning OTM and seal reliability over extended periods and through various chemical and thermal shocks and cycles was also obtained. These findings were used to develop several conceptual designs for pilot (10 kWe) and commercial-scale (250 kWe) SOFC/OTM zero emission power generation systems.

G. Maxwell Christie; Troy M. Raybold

2003-06-10T23:59:59.000Z

231

ION CHANNELS The Na/K-ATPase/Src complex and cardiotonic  

E-Print Network [OSTI]

machine for the ATP-dependent and -coupled transport of Na+ and K+ across the plasma membrane of a living sarcoplasmic reticulum Ca-ATPase Introduction The P-type ATPases control ion fluxes across the cell membrane;allow the movement of ions across the cell membrane. They could also alter the function

Brand, Paul H.

232

A Discussion of Conductivity Testing in High Temperature Membranes (lessons learned in assessing transport)  

Broader source: Energy.gov [DOE]

Presentation on conductivity testing in high temperature membranes given by Jim Boncella of Los Alamos National Laboratory at the High Temperature Membrane Working Group meeting in October 2005.

233

2002 Macmillan Magazines Ltd Ion gradients are widely used in transmembrane signal-  

E-Print Network [OSTI]

. These gradients are established by the active transport of ions from low to high electrochemical potentials across the membrane, driven by coupling transport to an energetically favourable process, such as ATP hydrolysis by ion channels that are located in the postsynaptic membrane and activated by neurotransmitters

Alford, Simon

234

Two Chlamydomonas CTR Copper Transporters with a Novel Cys-Met Motif Are Localized to the Plasma Membrane and  

E-Print Network [OSTI]

Two Chlamydomonas CTR Copper Transporters with a Novel Cys-Met Motif Are Localized to the Plasma Membrane and Function in Copper Assimilation W M. Dudley Page, Janette Kropat, Patrice P. Hamel,1, California 90095-1569 Inducible high-affinity copper uptake is key to copper homeostasis in Chlamydomonas

Meier, Iris

235

Chamber transport of ''foot'' pulses for heavy-ion fusion  

SciTech Connect (OSTI)

Indirect-drive targets for heavy-ion fusion must initially be heated by ''foot'' pulses that precede the main heating pulses by tens of nanoseconds. These pulses typically have a lower energy and perveance than the main pulses, and the fusion-chamber environment is different from that seen by later pulses. The preliminary particle-in-cell simulations of foot pulses here examine the sensitivity of the beam focusing to ion-beam perveance, background-gas density, and pre-neutralization by a plasma near the chamber entry port.

Sharp, W.M.; Callahan-Miller, D.A.; Tabak, M.; Yu, S.S.; Peterson, P.F.

2002-02-20T23:59:59.000Z

236

Multiphase transport model for relativistic heavy ion collisions  

E-Print Network [OSTI]

of these results to experimental data, mainly from heavy ion collisions at the BNL Relativistic Heavy Ion Collider, are then made in order to extract information on the properties of the hot dense matter formed in these collisions. DOI: 10.1103/PhysRevC.72... quark and a diquark with weights according to relations from the SU(6) quark model [71], and the diquark is then decomposed into two quarks. The quark and diquark masses are taken to be the same as in the PYTHIA program [59], e.g.,mu = 5.6,md = 9.9...

Lin, ZW; Ko, Che Ming; Li, Ba; Zhang, B.; Pal, S.

2005-01-01T23:59:59.000Z

237

Computer Simulation and Comparison of Proton and Carbon Ion Treatment of Tumor Cells Using Particle and Heavy Ion Transport Code System  

E-Print Network [OSTI]

COMPUTER SIMULATION AND COMPARISON OF PROTON AND CARBON ION TREATMENT OF TUMOR CELLS USING PARTICLE AND HEAVY ION TRANSPORT CODE SYSTEM A Thesis by KEEL BRANDON CURTIS Submitted to the Office of Graduate Studies of Texas A... AND HEAVY ION TRANSPORT CODE SYSTEM A Thesis by KEEL BRANDON CURTIS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair...

Curtis, Keel Brandon

2011-02-22T23:59:59.000Z

238

Effect of an equilibrium phase transition on multiphase transport in relativistic heavy ion collisions  

Science Journals Connector (OSTI)

The hadronization scheme for parton transport in relativistic heavy ion collisions is considered in detail. It is pointed out that the traditional scheme for particles being freezed out one by one leads to serious problem on unreasonable long lifetime of partons. A collective phase transition following a supercooling is implemented in a simple way. It turns out that the modified model with a sudden phase transition is able to reproduce the experimental longitudinal distributions of final state particles better than the original one does. The encouraging results indicate that equilibrium phase transition should be taken into proper account in parton transport models for relativistic heavy ion collisions.

Yu Meiling; Du Jiaxin; Liu Lianshou

2006-10-30T23:59:59.000Z

239

A computational study of ion conductance in the KcsA K+ using a NernstPlanck model with explicit resident ions  

E-Print Network [OSTI]

membranes, new transport mechanisms evolved to allow ionized substrates into the cell and release ionized waste products into the environment.1 For the membrane to retain vital cell compo- nents, the transport the ion and wa- ter cannot get past each other transport devices such that every living cell in nearly all

Lu, Benzhuo

240

PHYSICAL REVIEW E 85, 031914 (2012) Ion fluxes through nanopores and transmembrane channels  

E-Print Network [OSTI]

]. The channels serve to establish an electrostatic potential gradient across the cell membrane by allowing an ion-specific flux to pass through the membrane. There are many different ion channels in living cells. They differ, in practice, it is well known that when open, ion channels sustain a very large ionic transport rate

Levin, Yan

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Ion beam sputter etching of galliumnitride grown by chloride transport LPCVD  

Science Journals Connector (OSTI)

Galliumnitrid (GaN) layers, grown by chloride transport LPCVD, were etched by ion beam sputtering with carbon dioxide (CO2). Before etching all samples were masked by electron beam evaporated titanium. We report on the dependence of the etch rate on the angle of incidence of the ion beam. Furthermore we present structural examinations of the surface before and after ion etching as well as an analysis of masking effects. Surface roughening and structural defects were investigated by optical microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Michael Topf; Fehmi Cavas; Bruno K Meyer; Bertilo Kempf; Walter Betz; Peter Veit

1999-01-01T23:59:59.000Z

242

Direct photon emission in Heavy Ion Collisions from Microscopic Transport Theory and Fluid Dynamics  

E-Print Network [OSTI]

Direct photon emission in heavy-ion collisions is calculated within a relativistic micro+macro hybrid model and compared to the microscopic transport model UrQMD. In the hybrid approach, the high-density part of the collision is calculated by an ideal 3+1-dimensional hydrodynamic calculation, while the early (pre-equilibrium-) and late (rescattering-) phase are calculated with the transport model. Different scenarios of the transition from the macroscopic description to the transport model description and their effects are studied. The calculations are compared to measurements by the WA98-collaboration and predictions for the future CBM-experiment are made.

Bjoern Baeuchle; Marcus Bleicher

2010-03-29T23:59:59.000Z

243

Comparison between single- and dual-electrode ion source systems for low-energy ion transport  

SciTech Connect (OSTI)

Extraction of ions with energies below 100 eV has been demonstrated using a hot-cathode multi-cusp ion source equipped with extraction electrodes made of thin wires. Two electrode geometries, a single-electrode system, and a dual-electrode system were built and tested. The single-electrode configuration showed high ion beam current densities at shorter distances from the electrode but exhibited rapid attenuation as the distance from the electrode increased. Beam angular spread measurements showed similar beam divergence for both electrode configurations at low plasma densities. At high plasma densities and low extraction potentials, the single-electrode system showed the angular spread twice as large as that of the dual-electrode system. Energy distribution analyses showed a broader energy spread for ion beams extracted from a single-electrode set-up.

Vasquez, M. Jr.; Tokumura, S.; Kasuya, T.; Maeno, S.; Wada, M. [Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-321 and Nissin Ion Equipment Co., Ltd. 575 Kuze Tonoshiro-cho, Minami-ku, Kyoto 601-8205 (Japan); Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-321 (Japan); Novelion Systems Co.Ltd., D-Egg, Kyotanabe, Kyoto 610-332 (Japan); Graduate School of Science and Engineering, Doshisha University, Kyotanabe, Kyoto 610-321 (Japan)

2012-11-06T23:59:59.000Z

244

Poisson-Nernst-Planck systems for narrow tubular-like membrane and Bixiang Wang  

E-Print Network [OSTI]

membrane channels, transport of holes and electrons in semiconductors (see, e.g., [1, 2, 24, 4, 6, 7, 8, 17, 25]). In the context of ion flow through membrane channels, it is physicallyPoisson-Nernst-Planck systems for narrow tubular-like membrane channels Weishi Liu and Bixiang Wang

Liu, Weishi

245

Conformational Exchange in a Membrane Transport Protein Is Altered in Protein Crystals  

SciTech Connect (OSTI)

Successful macromolecular crystallography requires solution conditions that may alter the conformational sampling of a macromolecule. Here, site-directed spin labeling is used to examine a conformational equilibrium within BtuB, the Escherichia coli outer membrane transporter for vitamin B{sub 12}. Electron paramagnetic resonance (EPR) spectra from a spin label placed within the N-terminal energy coupling motif (Ton box) of BtuB indicate that this segment is in equilibrium between folded and unfolded forms. In bilayers, substrate binding shifts this equilibrium toward the unfolded form; however, EPR spectra from this same spin-labeled mutant indicate that this unfolding transition is blocked in protein crystals. Moreover, crystal structures of this spin-labeled mutant are consistent with the EPR result. When the free energy difference between substates is estimated from the EPR spectra, the crystal environment is found to alter this energy by 3 kcal/mol when compared to the bilayer state. Approximately half of this energy change is due to solutes or osmolytes in the crystallization buffer, and the remainder is contributed by the crystal lattice. These data provide a quantitative measure of how a conformational equilibrium in BtuB is modified in the crystal environment, and suggest that more-compact, less-hydrated substates will be favored in protein crystals.

D Freed; P Horanyi; M Wiener; D Cafiso

2011-12-31T23:59:59.000Z

246

Conformational Exchange in a Membrane Transport Protein Is Altered in Protein Crystals  

SciTech Connect (OSTI)

Successful macromolecular crystallography requires solution conditions that may alter the conformational sampling of a macromolecule. Here, site-directed spin labeling is used to examine a conformational equilibrium within BtuB, the Escherichia coli outer membrane transporter for vitamin B{sub 12}. Electron paramagnetic resonance (EPR) spectra from a spin label placed within the N-terminal energy coupling motif (Ton box) of BtuB indicate that this segment is in equilibrium between folded and unfolded forms. In bilayers, substrate binding shifts this equilibrium toward the unfolded form; however, EPR spectra from this same spin-labeled mutant indicate that this unfolding transition is blocked in protein crystals. Moreover, crystal structures of this spin-labeled mutant are consistent with the EPR result. When the free energy difference between substates is estimated from the EPR spectra, the crystal environment is found to alter this energy by 3 kcal/mol when compared to the bilayer state. Approximately half of this energy change is due to solutes or osmolytes in the crystallization buffer, and the remainder is contributed by the crystal lattice. These data provide a quantitative measure of how a conformational equilibrium in BtuB is modified in the crystal environment, and suggest that more-compact, less-hydrated substates will be favored in protein crystals.

Freed, Daniel M.; Horanyi, Peter S.; Wiener, Michael C.; Cafiso, David S. (UV)

2010-09-27T23:59:59.000Z

247

Chapter 11 - Nanofluidic Carbon Nanotube Membranes: Applications for Water Purification and Desalination  

Science Journals Connector (OSTI)

This chapter presents a brief overview of the basic physical processes that govern the structure and transport of water inside CNT pores, basic properties that make nanotube pore technologies attractive for water purification and desalination, the fabrication approaches for producing CNT membranes, and the experimental observations of water transport and ion exclusion properties in CNT membranes.

Olgica Bakajin; Aleksandr Noy; Francesco Fornasiero; Costas P. Grigoropoulos; Jason K. Holt; Jung Bin In; Sangil Kim; Hyung Gyu Park

2014-01-01T23:59:59.000Z

248

Active membrane fluctuations studied by micropipet aspiration J.-B. Manneville,1  

E-Print Network [OSTI]

, mostly performed by proteins embedded inside the lipid bi- layer, such as solute transport via ion channels or pumps, cell locomotion and adhesion, membrane transport through exo- cytic and endocyticActive membrane fluctuations studied by micropipet aspiration J.-B. Manneville,1 P. Bassereau,1

Ramaswamy, Sriram

249

Development of Novel active transport membrane devices. Phase I. Final report, 31 October 1988--31 January 1994  

SciTech Connect (OSTI)

The main objective of this program was to identify and develop a technique for fabricating Active Transport Materials (ATM) into lab-scale membrane devices. Air Products met this objective by applying thin film, multilayer fabrication techniques to support the AT material on a substrate membrane. In Phase IA, spiral-wound hollow fiber membrane modules were fabricated and evaluated. These nonoptimized devices were used to demonstrate the AT-based separation of carbon dioxide from methane, hydrogen sulfide from methane, and ammonia from hydrogen. It was determined that a need exists for a more cost efficient and less energy intensive process for upgrading subquality natural gas. Air Products estimated the effectiveness of ATM for this application and concluded that an optimized ATM system could compete effectively with both conventional acid gas scrubbing technology and current membrane technology. In addition, the optimized ATM system would have lower methane loss and consume less energy than current alternative processes. Air Products made significant progress toward the ultimate goal of commercializing an advanced membrane for upgrading subquality natural gas. The laboratory program focused on developing a high performance hollow fiber substrate and fabricating and evaluating ATM-coated lab-scale hollow fiber membrane modules. Selection criteria for hollow fiber composite membrane supports were developed and used to evaluate candidate polymer compositions. A poly(amide-imide), PAI, was identified for further study. Conditions were identified which produced microporous PAI support membrane with tunable surface porosity in the range 100-1000{Angstrom}. The support fibers exhibited good hydrocarbon resistance and acceptable tensile strength though a higher elongation may ultimately be desirable. ATM materials were coated onto commercial and PAI substrate fiber. Modules containing 1-50 fibers were evaluated for permselectivity, pressure stability, and lifetime.

Laciak, D.V.; Quinn, R.; Choe, G.S.; Cook, P.J.; Tsai, Fu-Jya

1994-08-01T23:59:59.000Z

250

Microporous Inorganic Membranes for Hydrogen Purification  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Microporous Microporous Inorganic Membranes for Hydrogen Purification Brian L. Bischoff, Roddie R. Judkins, and Timothy R. Armstrong Oak Ridge National Laboratory Presented at: DOE Workshop on Hydrogen Separations and Purification Technologies Arlington, Virginia September 8, 2004 2 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY Hydrogen Separation Membranes * Non-Porous - Palladium based films - Ion transport membranes * Porous - Ordered microporous membranes (IUPAC Recommendations 2001), e.g. zeolite membranes - Microporous membranes 3 OAK RIDGE NATIONAL LABORATORY U. S. DEPARTMENT OF ENERGY Microporous Membranes * IUPAC defines micropores as pores smaller than 2nm in diameter * Generally a microporous membrane is made by applying 1 to 3 thin layers to a porous support * Porous support can be ceramic or metallic

251

Genes Related to Ion-Transport and Energy Production Are Upregulated in Response to CO2-Driven pH Decrease  

E-Print Network [OSTI]

Genes Related to Ion-Transport and Energy Production Are Upregulated in Response to CO2-Driven p. (2013) Genes Related to Ion-Transport and Energy Production Are Upregulated in Response to CO2-Driven p

Paris-Sud XI, Université de

252

Deletions of SKY1 or PTK2 in the Saccharomyces cerevisiae trk1Dtrk2D mutant cells exert dual effect on ion homeostasis  

E-Print Network [OSTI]

that regulate ion transport across the plasma membrane of Saccharomyces cerevisiae. We show here that deletion to spermine and salt ions. A model that integrates these results to explain the mechanism of ion transport on ion homeostasis Omri Erez and Chaim Kahana* Department of Molecular Genetics, Weizmann Institute

Kahana, Chaim

253

Aptamer Directly Evolved from Live Cells Recognizes Membrane Bound Immunoglobin  

E-Print Network [OSTI]

. These include cell signaling, cell-cell interactions, ion/solute transport that facilitates the exchangeAptamer Directly Evolved from Live Cells Recognizes Membrane Bound Immunoglobin Heavy Mu Chain, and Weihong Tan The identification of tumor related cell membrane protein targets is important

Tan, Weihong

254

Packing Interactions between Transmembrane Helices Alter Ion Selectivity of the Yeast Golgi Ca2  

E-Print Network [OSTI]

(SERCA) and plasma membrane (PMCA) Ca2 - ATPases (3, 4). Perhaps the most interesting transport charac- teristic of SPCA pumps is their unique ability to transport Mn2 ions with high affinity (1, 2 of the binding pocket resulting in vectorial ion transport (7). The x-ray crystal struc- ture of SERCA in the E1

Rao, Rajini

255

Conceptual design report for a Direct Hydrogen Proton Exchange Membrane Fuel Cell for transportation application  

SciTech Connect (OSTI)

This report presents the conceptual design for a Direct-Hydrogen-Fueled Proton Exchange Membrane (PEM) Fuel Cell System for transportation applications. The design is based on the initial selection of the Chrysler LH sedan as the target vehicle with a 50 kW (gross) PEM Fuel Cell Stack (FCS) as the primary power source, a battery-powered Load Leveling Unit (LLU) for surge power requirements, an on-board hydrogen storage subsystem containing high pressure gaseous storage, a Gas Management Subsystem (GMS) to manage the hydrogen and air supplies for the FCS, and electronic controllers to control the electrical system. The design process has been dedicated to the use of Design-to-Cost (DTC) principles. The Direct Hydrogen-Powered PEM Fuel Cell Stack Hybrid Vehicle (DPHV) system is designed to operate on the Federal Urban Driving Schedule (FUDS) and Hiway Cycles. These cycles have been used to evaluate the vehicle performance with regard to range and hydrogen usage. The major constraints for the DPHV vehicle are vehicle and battery weight, transparency of the power system and drive train to the user, equivalence of fuel and life cycle costs to conventional vehicles, and vehicle range. The energy and power requirements are derived by the capability of the DPHV system to achieve an acceleration from 0 to 60 MPH within 12 seconds, and the capability to achieve and maintain a speed of 55 MPH on a grade of seven percent. The conceptual design for the DPHV vehicle is shown in a figure. A detailed description of the Hydrogen Storage Subsystem is given in section 4. A detailed description of the FCS Subsystem and GMS is given in section 3. A detailed description of the LLU, selection of the LLU energy source, and the power controller designs is given in section 5.

NONE

1995-09-05T23:59:59.000Z

256

Membrane Porters of ATP-Binding Cassette Transport Systems Are Polyphyletic  

E-Print Network [OSTI]

REVIEW Membrane Porters of ATP-Binding Cassette Transportat Springerlink.com Abstract The ATP-binding cassette (ABC)classi?ed according to the ATP hydrolyzing constituents,

Wang, Bin; Dukarevich, Maxim; Sun, Eric I.; Yen, Ming Ren; Saier, Milton H.

2009-01-01T23:59:59.000Z

257

Effect of equilibrium phase transition on multiphase transport in relativistic heavy ion collisions  

E-Print Network [OSTI]

The hadronization scheme for parton transport in relativistic heavy ion collisions is considered in detail. It is pointed out that the traditional scheme for particles being freezed out one by one leads to serious problem on unreasonable long lifetime for partons. A super-cooling of the parton system followed by a collective phase transition is implemented in a simple way. It turns out that the modified model with a global phase transition is able to reproduce the experimental longitudinal distributions of final state particles better than the original one does. The encouraging results indicate that a relevant parton transport model for relativistic heavy ion collision should take equilibrium phase transition into proper account.

Yu Meiling; Du Jiaxin; Liu Lianshou

2006-06-24T23:59:59.000Z

258

Internal Transport Barrier with Ion-Cyclotron-Resonance Minority Heating on Tore Supra  

Science Journals Connector (OSTI)

Recently, reversed magnetic shear operation was performed using only ion-cyclotron-resonance frequency minority heating (ICRH) during current ramp-up. A wide region of reversed magnetic shear has been obtained. For the first time, an electron internal transport barrier sustained by ICRH is observed, with a dramatical drop of density fluctuations. This barrier was maintained, on the current flat top, for about 2 s.

G. T. Hoang; C. Bourdelle; X. Garbet; G. Antar; R. V. Budny; T. Aniel; V. Basiuk; A. Bcoulet; P. Devynck; J. Lasalle; G. Martin; F. Saint-Laurent; the Tore Supra Team

2000-05-15T23:59:59.000Z

259

Selective Gas Transport Through Few-Layered Graphene and Graphene Oxide Membranes  

Science Journals Connector (OSTI)

...for membrane applications because of ultimate...deposition (CVD) has recently...synthesized via CVD has a polycrystalline...spray and spin coatings (16). GO films...after several coatings, both membrane...coated by a GO thin film without detectable...cracks under an optical microscope...

Hyo Won Kim; Hee Wook Yoon; Seon-Mi Yoon; Byung Min Yoo; Byung Kook Ahn; Young Hoon Cho; Hye Jin Shin; Hoichang Yang; Ungyu Paik; Soongeun Kwon; Jae-Young Choi; Ho Bum Park

2013-10-04T23:59:59.000Z

260

Water Transport in Polymer Electrolyte Membrane Electrolyzers Used to Recycle Anhydrous HCl  

E-Print Network [OSTI]

is car- ried out in an electrolyzer similar to a H2-O2 polymer electrolyte membrane PEM fuel cell. The Du-coated Nafion 115 membrane was measured as a function of HCl flow rate and temperature at a constant cell 50% of the chlorine used in the chemical industry ends up as hydrogen chloride, a waste byproduct.2

Weidner, John W.

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Controlling the transport of an ion: Classical and quantum mechanical solutions  

E-Print Network [OSTI]

We investigate the performance of different control techniques for ion transport in state-of-the-art segmented miniaturized ion traps. We employ numerical optimization of classical trajectories and quantum wavepacket propagation as well as analytical solutions derived from invariant based inverse engineering and geometric optimal control. We find that accurate shuttling can be performed with operation times below the trap oscillation period. The maximum speed is limited by the maximum acceleration that can be exerted on the ion. When using controls obtained from classical dynamics for wavepacket propagation, wavepacket squeezing is the only quantum effect that comes into play for a large range of trapping parameters. We show that this can be corrected by a compensating force derived from invariant based inverse engineering, without a significant increase in the operation time.

H. A. Frst; M. H. Goerz; U. G. Poschinger; M. Murphy; S. Montangero; T. Calarco; F. Schmidt-Kaler; K. Singer; C. P. Koch

2013-12-15T23:59:59.000Z

262

Formation of electron internal transport barrier and achievement of high ion temperature in Large Helical Device  

Science Journals Connector (OSTI)

An internal transport barrier(ITB) was observed in the electron temperature profile in the Large Helical Device [O. Motojima et al. Phys. Plasmas6 1843 (1999)] with a centrally focused intense electron cyclotron resonancemicrowaveheating. Inside the ITB the core electron transport was improved and a high electron temperature exceeding 10 keV in a low density was achieved in a collisionless regime. The formation of the electron-ITB is correlated with the neoclassical electron root with a strong radial electric field determined by the neoclassical ambipolar flux. The direction of the tangentially injected beam-driven current has an influence on the electron-ITB formation. For the counter-injected target plasma a steeper temperature gradient than that for the co-injected one was observed. As for the ion temperature high-power NBI (neutral beam injection) heating of 9 MW has realized a central ion temperature of 5 keV with neon injection. By introducing neon gas the NBI absorption power was increased in low-density plasmas and the direct ion heating power was much enhanced with a reduced number of ions compared with hydrogen plasmas.

Y. Takeiri; T. Shimozuma; S. Kubo; S. Morita; M. Osakabe; O. Kaneko; K. Tsumori; Y. Oka; K. Ikeda; N. Ohyabu; K. Ida; M. Yokoyama; J. Miyazawa; M. Goto; K. Narihara; I. Yamada; H. Idei; Y. Yoshimura; N. Ashikawa; M. Emoto; H. Funaba; M. Isobe; K. Kawahata; K. Khlopenkov; T. Kobuchi; A. Komori; A. Kostrioukov; R. Kumazawa; Y. Liang; S. Masuzaki; T. Minami; T. Morisaki; S. Murakami; S. Muto; T. Mutoh; Y. Nagayama; Y. Nakamura; H. Nakanishi; Y. Narushima; K. Nishimura; N. Noda; S. Ohdachi; T. Ozaki; B. J. Peterson; A. Sagara; K. Saito; S. Sakakibara; R. Sakamoto; M. Sasao; M. Sato; T. Seki; M. Shoji; H. Suzuki; N. Tamura; K. Tanaka; K. Toi; T. Tokuzawa; K. Y. Watanabe; T. Watari; Y. Xu; H. Yamada; M. Yoshinuma; K. Itoh; K. Ohkubo; T. Satow; S. Sudo; T. Uda; K. Yamazaki; Y. Hamada; K. Matsuoka; O. Motojima; M. Fujiwara; T. Notake; N. Takeuchi; Y. Torii; S. Yamamoto; T. Yamamoto; T. Akiyama; P. Goncharov; T. Saida; H. Kawazome; H. Nozato

2003-01-01T23:59:59.000Z

263

Self-Assembly and Mass Transport in Membranes for Artificial Photosynthesis  

E-Print Network [OSTI]

45 CHAPTER 3. SELF-ASSEMBLY AND TRANSPORT LIMITATIONS IN7371. CHAPTER 3. SELF-ASSEMBLY AND TRANSPORT LIMITATIONS IN2. CONTROLLING NANOROD SELF-ASSEMBLY IN POLYMER THIN-FILMS

Modestino, Miguel Antonio

2013-01-01T23:59:59.000Z

264

Tail-ion transport and Knudsen layer formation in the presence of magnetic fields  

SciTech Connect (OSTI)

Knudsen layer losses of tail fuel ions could reduce significantly the fusion reactivity of highly compressed cylindrical and spherical targets in inertial confinement fusion (ICF). With the class of magnetized ICF targets in mind, the effect of embedded magnetic fields on Knudsen layer formation is investigated for the first time. The modified energy scaling of ion diffusivity in magnetized hot spots is found to suppress the preferential losses of tail-ions perpendicular to the magnetic field lines to a degree that the tail distribution can be at least partially, if not fully, restored. Two simple threshold conditions are identified leading to the restoration of fusion reactivity in magnetized hot spots. A kinetic equation for tail-ion transport in the presence of a magnetic field is derived, and solutions to the equation are obtained numerically in simulations. Numerical results confirm the validity of the threshold conditions for restored reactivity and identify two different asymptotic regimes of the fusion fuel. While Knudsen layer formation is shown to be suppressed entirely in strongly magnetized cylindrical hot spot cavities, uniformly magnetized spherical cavities demonstrate remnant, albeit reduced, levels of tail-ion depletion.

Schmit, P. F. [Sandia National Laboratories, MS 1186, P.O. Box 5800, Albuquerque, New Mexico 87185-1186 (United States)] [Sandia National Laboratories, MS 1186, P.O. Box 5800, Albuquerque, New Mexico 87185-1186 (United States); Molvig, Kim; Nakhleh, C. W. [Los Alamos National Laboratory, MS B259, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, MS B259, P.O. Box 1663, Los Alamos, New Mexico 87545 (United States)

2013-11-15T23:59:59.000Z

265

Investigation of the performance and water transport of a polymer electrolyte membrane (pem) fuel cell  

E-Print Network [OSTI]

Fuel cell performance was obtained as functions of the humidity at the anode and cathode sites, back pressure, flow rate, temperature, and channel depth. The fuel cell used in this work included a membrane and electrode assembly (MEA) which...

Park, Yong Hun

2009-05-15T23:59:59.000Z

266

Self-Assembly and Mass Transport in Membranes for Artificial Photosynthesis  

E-Print Network [OSTI]

membranes are in hydrogen fuel- cells and electrolyzers. Thefuel cells and electrolyzers used both for hydrogenhydrogen production and device geometry requirements dictated by the light absorption. In fuel cells,

Modestino, Miguel Antonio

2013-01-01T23:59:59.000Z

267

Experimental characterization of water sorption and transport properties of polymer electrolyte membranes for fuel cells.  

E-Print Network [OSTI]

??L'objectif gnral de cette thse de doctorat est de caractriser les proprits de membranes PFSA de type Nafion N115 et Nafion NRE212 en termes de (more)

Maldonado Snchez, Libeth

2012-01-01T23:59:59.000Z

268

New possibilities of electroinduced membrane gas and vapor separation  

SciTech Connect (OSTI)

A novel membrane technique to effect electroinduced facilitated transport of neutral molecules in ion-exchange membranes was suggested. Experiments have been carried out with platinum-coated Nafion membranes in Cu{sup 2+}/Cu{sup 1+} form. This may be a potential technique for the separation of olefin/paraffin mixtures. It was shown that by applying an electric current to the membrane the permeability of ethylene increased 6-fold, compared to the permeability of the initial Pt-coated membrane without current.

Bessarabov, D.G.; Sanderson, R.D. [Univ. of Stellenbosch (South Africa). Inst. for Polymer Science] [Univ. of Stellenbosch (South Africa). Inst. for Polymer Science; Valuev, V.V.; Popkov, Y.M.; Timashev, S.F. [Karpov Inst. of Physical Chemistry, Moscow (Russian Federation)] [Karpov Inst. of Physical Chemistry, Moscow (Russian Federation)

1997-06-01T23:59:59.000Z

269

Benchmarking Heavy Ion Transport Codes FLUKA, HETC-HEDS MARS15, MCNPX, and PHITS  

SciTech Connect (OSTI)

Powerful accelerators such as spallation neutron sources, muon-collider/neutrino facilities, and rare isotope beam facilities must be designed with the consideration that they handle the beam power reliably and safely, and they must be optimized to yield maximum performance relative to their design requirements. The simulation codes used for design purposes must produce reliable results. If not, component and facility designs can become costly, have limited lifetime and usefulness, and could even be unsafe. The objective of this proposal is to assess the performance of the currently available codes â?? PHITS, FLUKA, MARS15, MCNPX, and HETC-HEDS â?? that could be used for design simulations involving heavy ion transport. We plan to access their performance by performing simulations and comparing results against experimental data of benchmark quality. Quantitative knowledge of the biases and the uncertainties of the simulations is essential as this potentially impacts the safe, reliable and cost effective design of any future radioactive ion beam facility. Further benchmarking of heavy-ion transport codes was one of the actions recommended in the â??Report of the 2003 RIA R&D Workshop".

Ronningen, Reginald Martin [Michigan State University; Remec, Igor [Oak Ridge National Laboratory; Heilbronn, Lawrence H. [University of Tennessee-Knoxville

2013-06-07T23:59:59.000Z

270

E-Print Network 3.0 - anandamide membrane transporter Sample...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

of the putative anandamide transporter that also... , Kaczocha M, Studholme KM, Deutsch DG (2003). Evidence against the presence of an ... Source: Cravatt, Benjamin -...

271

Haemocompatibility and ion exchange capability of nanocellulose polypyrrole membranes intended for blood purification  

Science Journals Connector (OSTI)

...highly purified water. The increasing...haemodialysis membranes and dialysis technology that...following groups: small water-soluble compounds...difficult to remove by dialysis. The failure to...during dialysis treatments [1]. However...extraction [11] and electric energy storage...

2012-01-01T23:59:59.000Z

272

The tokamak Monte Carlo fast ion module NUBEAM in the National Transport Code Collaboration library  

Science Journals Connector (OSTI)

The NUBEAM module is a comprehensive computational model for Neutral Beam Injection (NBI) in tokamaks. It is used to compute power deposition, driven current, momentum transfer, fueling, and other profiles in tokamak plasmas due to NBI. NUBEAM computes the time-dependent deposition and slowing down of the fast ions produced by NBI, taking into consideration beam geometry and composition, ion-neutral interactions (atomic physics), anomalous diffusion of fast ions, the effects of large scale instabilities, the effect of magnetic ripple, and finite Larmor radius effects. The NUBEAM module can also treat fusion product ions that contribute to alpha heating and ash accumulation, whether or not NBI is present. These physical phenomena are important in simulations of present day tokamaks and projections to future devices such as ITER. The NUBEAM module was extracted from the TRANSP integrated modeling code, using standards of the National Transport Code Collaboration (NTCC), and was submitted to the NTCC module library (http://w3.pppl.gov/NTCC). This paper describes the physical processes computed in the NUBEAM module, together with a summary of the numerical techniques that are used. The structure of the NUBEAM module is described, including its dependence on other NTCC library modules. Finally, a description of the procedure for setting up input data for the NUBEAM module and making use of the output is outlined.

Alexei Pankin; Douglas McCune; Robert Andre; Glenn Bateman; Arnold Kritz

2004-01-01T23:59:59.000Z

273

Computational and experimental study of nanoporous membranes for water desalination and decontamination.  

SciTech Connect (OSTI)

Fundamentals of ion transport in nanopores were studied through a joint experimental and computational effort. The study evaluated both nanoporous polymer membranes and track-etched nanoporous polycarbonate membranes. The track-etched membranes provide a geometrically well characterized platform, while the polymer membranes are more closely related to ion exchange systems currently deployed in RO and ED applications. The experimental effort explored transport properties of the different membrane materials. Poly(aniline) membranes showed that flux could be controlled by templating with molecules of defined size. Track-etched polycarbonate membranes were modified using oxygen plasma treatments, UV-ozone exposure, and UV-ozone with thermal grafting, providing an avenue to functionalized membranes, increased wettability, and improved surface characteristic lifetimes. The modeling effort resulted in a novel multiphysics multiscale simulation model for field-driven transport in nanopores. This model was applied to a parametric study of the effects of pore charge and field strength on ion transport and charge exclusion in a nanopore representative of a track-etched polycarbonate membrane. The goal of this research was to uncover the factors that control the flux of ions through a nanoporous material and to develop tools and capabilities for further studies. Continuation studies will build toward more specific applications, such as polymers with attached sulfonate groups, and complex modeling methods and geometries.

Hickner, Michael A. (Penn State University, University Park, PA); Chinn, Douglas Alan (Sandia National Laboratories, Albuquerque, NM); Adalsteinsson, Helgi; Long, Kevin R. (Texas Tech University, Lubbock, TX); Kent, Michael Stuart (Sandia National Laboratories, Albuquerque, NM); Debusschere, Bert J.; Zendejas, Frank J.; Tran, Huu M.; Najm, Habib N.; Simmons, Blake Alexander

2008-11-01T23:59:59.000Z

274

Measurements of water uptake and transport properties in anion-exchange membranes  

E-Print Network [OSTI]

, the electro-osmotic drag (EOD) coefficient, and the mass-transfer coefficient of water at the cathode catalyst/membrane interface falls in the range of 1.0 ? 10?6 to 1.0 ? 10?5 m s?1 . The EOD coefficients measured at 30 C

Zhao, Tianshou

275

Molecular Basis for Nanoscopic Membrane Curvature Generation from Quantum Mechanical Models and Synthetic Transporter  

E-Print Network [OSTI]

that an arginine-rich, 11AA sequence from the transactivator of transcription (TAT) protein of HIV, YGRKKRRQRRR (CPP) such as the TAT peptide can efficiently translocate across cellular membranes.1-6 Many types, now referred to as the TAT peptide, is sufficient for cellular uptake. It was soon realized by Wender

Tew, Gregory N.

276

Supplementary Material An ion-channel-containing model membrane: structural determination by magnetic contrast  

E-Print Network [OSTI]

by magnetic contrast neutron reflectometry Stephen A. Holt,*a Anton P. Le Brun,b Charles F. Majkrzak,c Duncan, UK.; E-mail: Anton.Le-Brun@newcastle.ac.uk: j.h.lakey@ncl.ac.uk c NIST Center for Neutron Research, Auckland 1142, NZ.; E-mail: d.mcgillivray@auckland.ac.nz Keywords: OmpF; Outer membrane; porin; neutron

Loesche, Mathias

277

Joining of Ion Transport Membranes Using a Novel Transient Liquid Phase Process  

SciTech Connect (OSTI)

The feasibility of a novel transient liquid phase (TLP) joining method has been demonstrated in joining La{sub 0.9}Ca{sub 0.1}FeO{sub 3} materials. Metal oxide powders were processed to form the TLP compositions which were used in the joining process. The method has been successful in producing joint interfaces that effectively disappear, as they are the same material and have the same properties as the joined parts. The feasibility of the method has been demonstrated for a single system, but many systems where the method can potentially be applied have been identified.

Darryl P. Butt

2006-08-30T23:59:59.000Z

278

Compounds having aromatic rings and side-chain amide-functionality and a method for transporting monovalent anions across biological membranes using the same  

DOE Patents [OSTI]

A compound containing at least two aromatic rings covalently bonded together, with each aromatic ring containing at least one oxyacetamide-based side chain, the compound being capable of forming a chloride ion channel across a lipid bilayer, and transporting chloride ion across the lipid bilayer.

Davis, Jeffery T. (College Park, MD); Sidorov, Vladimir (Richmond, VA); Kotch, Frank W. (New Phila., PA)

2008-04-08T23:59:59.000Z

279

Zinc and Health: Current Status and Future Directions Zinc Transport in the Brain: Routes of Zinc Influx and Efflux in Neurons1,2  

E-Print Network [OSTI]

homeostasis. J. Nutr. 130: 1484S--1487S, 2000. KEY WORDS: zinc ion transport heavy metal ions trace and that mediate extracellular zinc toxicity and (3) a plasma membrane transporter potentially present in all elements metal transporters rat Large amounts of zinc are present in the brain, yet very little

280

Multi-block sulfonated poly(phenylene) copolymer proton exchange membranes  

DOE Patents [OSTI]

Improved multi-block sulfonated poly(phenylene) copolymer compositions, methods of making the same, and their use as proton exchange membranes (PEM) in hydrogen fuel cells, direct methanol fuel cells, in electrode casting solutions and electrodes. The multi-block architecture has defined, controllable hydrophobic and hydrophilic segments. These improved membranes have better ion transport (proton conductivity) and water swelling properties.

Fujimoto, Cy H. (Albuquerque, NM); Hibbs, Michael (Albuquerque, NM); Ambrosini, Andrea (Albuquerque, NM)

2012-02-07T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Ammonium Bicarbonate Transport in Anion Exchange Membranes for Salinity Gradient Energy  

E-Print Network [OSTI]

such as reverse electrodialysis (RED) rely on highly selective anion transport through polymeric anion exchange to address global energy needs, such as reverse electro- dialysis1-4 (RED), capacitive energy extraction based on Donnan potential5 (CDP), and capacitive reverse electro- dialysis6 (CRED), has encouraged

282

ReaxFF Reactive Force Field for Solid Oxide Fuel Cell Systems with Application to Oxygen Ion Transport in Yttria-Stabilized Zirconia  

E-Print Network [OSTI]

ReaxFF Reactive Force Field for Solid Oxide Fuel Cell Systems with Application to Oxygen Ion through yttria-stabilized zirconia (YSZ) solid oxide fuel cell (SOFC) membranes. All parameters for Reax temperature, leading to applications as oxygen sensors and as membranes for high temperature solid oxide fuel

Goddard III, William A.

283

Assembly and Repair of Membrane-Bound Electron Transport Complexes similar to NifS than is Slr0387, but shows strong  

E-Print Network [OSTI]

Assembly and Repair of Membrane-Bound Electron Transport Complexes similar to NifS than is Slr0387 in the maturation of FeS proteins. We found that under some conditions the Synechocystis NifU-like protein can oxidation of the cysteine side chains at NifU. The same reaction might have occurred in lysed chloroplasts

284

Proton conducting ceramic membranes for hydrogen separation  

DOE Patents [OSTI]

A multi-phase proton conducting material comprising a proton-conducting ceramic phase and a stabilizing ceramic phase. Under the presence of a partial pressure gradient of hydrogen across the membrane or under the influence of an electrical potential, a membrane fabricated with this material selectively transports hydrogen ions through the proton conducting phase, which results in ultrahigh purity hydrogen permeation through the membrane. The stabilizing ceramic phase may be substantially structurally and chemically identical to at least one product of a reaction between the proton conducting phase and at least one expected gas under operating conditions of a membrane fabricated using the material. In a barium cerate-based proton conducting membrane, one stabilizing phase is ceria.

Elangovan, S. (South Jordan, UT); Nair, Balakrishnan G. (Sandy, UT); Small, Troy (Midvale, UT); Heck, Brian (Salt Lake City, UT)

2011-09-06T23:59:59.000Z

285

Electron Transport and Ion Acceleration in a Low-power Cylindrical Hall Thruster  

SciTech Connect (OSTI)

Conventional annular Hall thrusters become inefficient when scaled to low power. Cylindrical Hall thrusters, which have lower surface-to-volume ratio, are therefore more promising for scaling down. They presently exhibit performance comparable with conventional annular Hall thrusters. Electron cross-field transport in a 2.6 cm miniaturized cylindrical Hall thruster (100 W power level) has been studied through the analysis of experimental data and Monte Carlo simulations of electron dynamics in the thruster channel. The numerical model takes into account elastic and inelastic electron collisions with atoms, electron-wall collisions, including secondary electron emission, and Bohm diffusion. We show that in order to explain the observed discharge current, the electron anomalous collision frequency {nu}{sub B} has to be on the order of the Bohm value, {nu}{sub B} {approx} {omega}{sub c}/16. The contribution of electron-wall collisions to cross-field transport is found to be insignificant. The plasma density peak observed at the axis of the 2.6 cm cylindrical Hall thruster is likely to be due to the convergent flux of ions, which are born in the annular part of the channel and accelerated towards the thruster axis.

A. Smirnov; Y. Raitses; N.J. Fisch

2004-06-24T23:59:59.000Z

286

Initialization of hydrodynamics in relativistic heavy ion collisions with an energy-momentum transport model  

E-Print Network [OSTI]

A key ingredient of hydrodynamical modeling of relativistic heavy ion collisions is thermal initial conditions, an input that is the consequence of a pre-thermal dynamics which is not completely understood yet. In the paper we employ a recently developed energy-momentum transport model of the pre-thermal stage to study influence of the alternative initial states in nucleus-nucleus collisions on flow and energy density distributions of the matter at the starting time of hydrodynamics. In particular, the dependence of the results on isotropic and anisotropic initial states is analyzed. It is found that at the thermalization time the transverse flow is larger and the maximal energy density is higher for the longitudinally squeezed initial momentum distributions. The results are also sensitive to the relaxation time parameter, equation of state at the thermalization time, and transverse profile of initial energy density distribution: Gaussian approximation, Glauber Monte Carlo profiles, etc. Also, test results ensure that the numerical code based on the energy-momentum transport model is capable of providing both averaged and fluctuating initial conditions for the hydrodynamic simulations of relativistic nuclear collisions.

V. Yu. Naboka; S. V. Akkelin; Iu. A. Karpenko; Yu. M. Sinyukov

2015-01-14T23:59:59.000Z

287

Evaluation of electrodialysis for scaling prevention of nanofiltration membranes at high water recoveries  

Science Journals Connector (OSTI)

The water recovery of nanofiltration in drinking water production is limited to 8085%. When the water recovery is increased, there is a risk of scaling of sparingly soluble salts, such as CaSO4 or CaCO3, onto the membrane surface. There is a need for robust technologies that handle the problem of mineral scaling in nanofiltration and reverse osmosis, allowing operation at higher recoveries, i.e., with a higher production of potable water. In this study, the retentate stream of a nanofiltration unit was therefore desalinated by electrodialysis. Two different ion exchange membrane pairs, namely AMX-CMX (Neosepta, Japan) and FTAM-FTCM (Fumasep, Germany) were used for this purpose. The membrane pairs were compared on the basis of their removal efficiency of the main ions present in natural waters, with special attention to calcium and sulphate ions. The economic feasibility of retentate treatment by electrodialysis is discussed as well. The FTAM anion exchange membranes of Fumasep were able to remove sulphate ions faster, relative to chloride or nitrate ions. This is unexpected, because sulphate ions have a high hydrated ionic radius and steric hindrance typically obstructs their transport through anion exchange membranes, as is the case with the AMX membranes. This feature makes the FTAM membranes appropriate for the desalination of retentate streams of nanofiltration and reverse osmosis membranes, in water recycling applications. The other membranes can be regarded as non-selective.

Steven Van Geluwe; Leen Braeken; Thomas Robberecht; Maarten Jans; Claude Creemers; Bart Van der Bruggen

2011-01-01T23:59:59.000Z

288

Phys. Med. Biol. 45 (2000) N157N165. Printed in the UK PII: S0031-9155(00)14256-3 Hydrodynamic effects on the solute transport across  

E-Print Network [OSTI]

Hydrodynamic effects on the solute transport across endothelial pores and hepatocyte membranes Dumitru Popescu, Liviu Movileanu§¶, Stelian Ion and Maria-Luiza Flonta Membrane Biophysics Laboratory, Institute membranes (Abidor et al 1979, Popescu et al 1991, Popescu and Victor 1991, Weaver and Chizmadzhev 1996

Movileanu, Liviu

289

Highly Confined Photon Transport in Subwavelength Metallic Slot Waveguides  

E-Print Network [OSTI]

was deposited on one side of a free-standing Si3N4 membrane. Using focused ion- beam milling, wire waveguidesHighly Confined Photon Transport in Subwavelength Metallic Slot Waveguides J. A. Dionne,*, H. J and electronic components. Although optical interconnects exhibit a large bandwidth for signal transport, minimum

Atwater, Harry

290

Molecular Squares as Molecular Sieves: Size-Selective Transport Through  

E-Print Network [OSTI]

Molecular Squares as Molecular Sieves: Size-Selective Transport Through Porous-Membrane squaresº: cyclic structures typically featuring metal-ion cor- ners and difunctional bridging ligands processes: size-selective molecular transport from a guest-containing solution to one initially free

291

Diagnostics of discharge channels for neutralized chamber transport in heavy ion fusion  

E-Print Network [OSTI]

ber of a heavy ion beam fusion reactor has many attractivein the reactor chamber for heavy ion fusion in preformedfusion. Controlled break- down and channel stability at reactor-

2002-01-01T23:59:59.000Z

292

Research and development of proton-exchange membrane (PEM) fuel cell system for transportation applications. Phase I final report  

SciTech Connect (OSTI)

Objective during Phase I was to develop a methanol-fueled 10-kW fuel cell power source and evaluate its feasibility for transportation applications. This report documents research on component (fuel cell stack, fuel processor, power source ancillaries and system sensors) development and the 10-kW power source system integration and test. The conceptual design study for a PEM fuel cell powered vehicle was documented in an earlier report (DOE/CH/10435-01) and is summarized herein. Major achievements in the program include development of advanced membrane and thin-film low Pt-loaded electrode assemblies that in reference cell testing with reformate-air reactants yielded performance exceeding the program target (0.7 V at 1000 amps/ft{sup 2}); identification of oxidation catalysts and operating conditions that routinely result in very low CO levels ({le} 10 ppm) in the fuel processor reformate, thus avoiding degradation of the fuel cell stack performance; and successful integrated operation of a 10-kW fuel cell stack on reformate from the fuel processor.

NONE

1996-01-01T23:59:59.000Z

293

Model Cell Membranes  

Science Journals Connector (OSTI)

... are being used as model systems to test particular hypotheses in membrane transport. Thus, Tosteson and his colleagues (Andreoli et al., J. Gen. PhysioL, 50, 1729; ...

A Correspondent

1968-01-13T23:59:59.000Z

294

Dual phase polymer gel electrolyte based on non-woven poly(vinylidenefluoride-co-hexafluoropropylene)layered clay nanocomposite fibrous membranes for lithium ion batteries  

SciTech Connect (OSTI)

Graphical abstract: Display Omitted Highlights: ? P(VdF-co-HFP)clay nanocomposite based electrospun membranes are prepared. ? The membranes are used as polymer gel electrolyte (PGE) in lithium ion batteries. ? The composite PGE shows ionic conductivity of 5.5 mS cm{sup ?1} at room temperature. ? Li/PGE/LiFePO{sub 4} cell delivers initial discharge capacity of 160 mAh g{sup ?1}. ? The use of prepared electrolyte significantly improved the cell performance. -- Abstract: A new approach for fabricating polymer gel electrolytes (PGEs) based on electrospun poly(vinylidenefluoride-co-hexafluoropropylene) (P(VdF-co-HFP)) incorporated with layered nanoclay has been employed to enhance the ionic conductivity and electrochemical properties of P(VdF-co-HFP) without compromising its mechanical strength. The effect of layered nanoclay on properties of membranes has been evaluated by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Surface morphology of the membranes has been studied using field-emission scanning electron microscopy (FE-SEM). Polymer gel electrolytes are prepared by soaking the fibrous membrane into 1 M LiPF{sub 6} in EC/DEC. The electrochemical studies show that incorporation of layered nanoclay into the polymer matrix greatly enhanced the ionic conductivity and compatibility with lithium electrodes. The chargedischarge properties and cycling performance of Li/LiFePO{sub 4} cells comprising nanocomposite polymer gel electrolytes have been evaluated at room temperature.

Shubha, Nageswaran [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore)] [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore); Prasanth, Raghavan [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore) [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore); Energy Research Institute - NTU (ERI-N) Research Techno Plaza, 50 Nanyang Drive, Singapore 637553 (Singapore); TUM-CREATE Center for Electromobility, Nanyang Technological University, Singapore 637553 (Singapore); Hoon, Hng Huey [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore)] [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore); Srinivasan, Madhavi, E-mail: madhavi@ntu.edu.sg [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore) [School of Materials Science and Engineering, Nanyang Technological University, Block N4.1, 50 Nanyang Avenue, Singapore 639798 (Singapore); Energy Research Institute - NTU (ERI-N) Research Techno Plaza, 50 Nanyang Drive, Singapore 637553 (Singapore); TUM-CREATE Center for Electromobility, Nanyang Technological University, Singapore 637553 (Singapore)

2013-02-15T23:59:59.000Z

295

Coupling of porous filtration and ion-exchange membranes in an electrodialysis stack and impact on cation selectivity: A novel approach for sea water demineralization and the production of physiological water  

Science Journals Connector (OSTI)

Conventional electrodialysis (ED) and electrodialysis with ultrafiltration (EDUF) or nanofiltration (EDNF) membrane treatments were carried-out for partial desalination of sea water and to evaluate their potential for the production of physiological water. A demineralization rate of 10.6% was obtained with the EDNF and of 40.25% with EDUF and conventional ED processes. The nanofiltration membrane, due to its high electrical resistance, slowed down the migrations of ions. Moreover, the use of an ultrafiltration membrane had no significant effect on the demineralization rate of sea water and the electrodialytic parameters in comparison with the use of conventional ED membranes. A demineralization rate between 20.5 and 30.1% was obtained for each cation analyzed following EDNF treatments and between 43.3 and 64.4% when conventional ED or EDUF was used. Moreover, the decrease in the concentration of monovalent ions was slightly larger than for divalent ions in the case of ED and EDUF while for EDNF, the higher decrease was observed for calcium ion. This means that the replacement of a cation-exchange membrane by an ultrafiltration membrane would not change the selectivity of the process for ion separation but with a nanofiltration membrane a cation-selectivity appears.

Laurent Bazinet; Marianne Moalic

2011-01-01T23:59:59.000Z

296

Impurity transport in Alcator C-Mod in the presence of poloidal density variation induced by ion cyclotron resonance heating  

E-Print Network [OSTI]

Impurity particle transport in an ion cyclotron resonance heated Alcator C-Mod discharge is studied with local gyrokinetic simulations and a theoretical model including the effect of poloidal asymmetries and elongation. In spite of the strong minority temperature anisotropy in the deep core region, the poloidal asymmetries are found to have negligible effect on the impurity transport due to low magnetic shear in this region, in agreement with the experimental observations. According to the theoretical model, in outer core regions poloidal asymmetries may contribute to the reduction of the impurity peaking, but uncertainties in atomic physics processes prevent quantitative comparison with experiments.

Molln, Albert; Reinke, Matthew L; Kazakov, Yevgen O; Howard, Nathan T; Flp, Tnde

2014-01-01T23:59:59.000Z

297

Survey of ion-acoustic-instability particle simulations and relevance to laser-fusion thermal-transport inhibition  

SciTech Connect (OSTI)

Ion acoustic turbulence is examined as one mechanism which could contribute to the inhibition of electron thermal transport which has been inferred from many laser-plasma experiments. The behavior of the ion acoustic instability is discussed from the viewpoint of the literature of 2-dimensional particle-in-cell simulations. Simulation techniques, limitations, and reported saturation mechanisms and levels are discussed. A scaling law for the effective collision frequency ..nu..* can be fit to several workers' results to within an order-of-magnitude. The inferred ..nu..* is shown to be 1-2 orders-of-magnitude too small to account for the transport inhibition seen in Nd-laser-produced plasmas. Several differences between the simulation conditions and laser-produced plasma conditions are noted.

Mead, W.C.

1980-09-11T23:59:59.000Z

298

J. Am. Chem. SOC.1994,116, 11203-11204 11203 Selective Dopamine Transport Using a Crown  

E-Print Network [OSTI]

with an ability to selectively transport catecholamines through a lipophilic membrane. In this report we describe ammonium ion^.^^^ With these systems, the order of observed transport rates has been primarily determinedJ. Am. Chem. SOC.1994,116, 11203-11204 11203 Selective Dopamine Transport Using a Crown Boronic

Smith, Bradley D.

299

Transportation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Transportation Transportation Transportation of Depleted Uranium Materials in Support of the Depleted Uranium Hexafluoride Conversion Program Issues associated with transport of depleted UF6 cylinders and conversion products. Conversion Plan Transportation Requirements The DOE has prepared two Environmental Impact Statements (EISs) for the proposal to build and operate depleted uranium hexafluoride (UF6) conversion facilities at its Portsmouth and Paducah gaseous diffusion plant sites, pursuant to the National Environmental Policy Act (NEPA). The proposed action calls for transporting the cylinder at ETTP to Portsmouth for conversion. The transportation of depleted UF6 cylinders and of the depleted uranium conversion products following conversion was addressed in the EISs.

300

Stochastic reconstruction and electrical transport studies of porous cathode of Li-ion batteries  

E-Print Network [OSTI]

of the Li-ion batteries through developing electrode materials [1e5], reducing size [6] and optimizing shape,13], as one of the main factors limiting Li-ion battery performance, has not been resolved. Fundamental the ulti- mate performance and stability. Theoretical work of Li-ion batteries has focused on macroscopic

Liu, Fuqiang

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Connectivity, clusters, and transport: use of percolation concepts and atomistic simulation to track intracellular ion migration  

Science Journals Connector (OSTI)

...track intracellular ion migration Ann Marie...Department of Mechanical Engineering and Department of...Department of Biomedical Engineering, University of...Article Review | 0 Ions 0 Metals 0 Molecular...track intracellular ion migration By A n...Department of Mechanical Engineering and Department of...

2004-01-01T23:59:59.000Z

302

Lithium Ion Transport Mechanism in Ternary Polymer Electrolyte-Ionic Liquid Mixtures - A Molecular Dynamics Simulation Study  

E-Print Network [OSTI]

The lithium transport mechanism in ternary polymer electrolytes, consisting of PEO/LiTFSI and various fractions of the ionic liquid N-methyl-N-propylpyrrolidinium bis(trifluoromethane)sulfonimide, are investigated by means of MD simulations. This is motivated by recent experimental findings [Passerini et al., Electrochim. Acta 2012, 86, 330-338], which demonstrated that these materials display an enhanced lithium mobility relative to their binary counterpart PEO/LiTFSI. In order to grasp the underlying microscopic scenario giving rise to these observations, we employ an analytical, Rouse-based cation transport model [Maitra at al., PRL 2007, 98, 227802], which has originally been devised for conventional polymer electrolytes. This model describes the cation transport via three different mechanisms, each characterized by an individual time scale. It turns out that also in the ternary electrolytes essentially all lithium ions are coordinated by PEO chains, thus ruling out a transport mechanism enhanced by the presence of ionic-liquid molecules. Rather, the plasticizing effect of the ionic liquid contributes to the increased lithium mobility by enhancing the dynamics of the PEO chains and consequently also the motion of the attached ions. Additional focus is laid on the prediction of lithium diffusion coefficients from the simulation data for various chain lengths and the comparison with experimental data, thus demonstrating the broad applicability of our approach.

Diddo Diddens; Andreas Heuer

2012-11-14T23:59:59.000Z

303

Role of Individual Positive Charges in the Membrane Orientation and Activity of Transporters of the Small Multidrug Resistance Family  

Science Journals Connector (OSTI)

Molecular Microbiology and Membrane Enzymology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands ... *Molecular Microbiology, Nijenborgh 7, 9747AG Groningen, The Netherlands. ...

Magdalena A. Kolbusz; Dirk Jan Slotboom; Juke S. Lolkema

2012-10-08T23:59:59.000Z

304

Crystal structure of a concentrative nucleoside transporter from Vibrio cholerae at 2.4;#8201;  

SciTech Connect (OSTI)

Nucleosides are required for DNA and RNA synthesis, and the nucleoside adenosine has a function in a variety of signalling processes. Transport of nucleosides across cell membranes provides the major source of nucleosides in many cell types and is also responsible for the termination of adenosine signalling. As a result of their hydrophilic nature, nucleosides require a specialized class of integral membrane proteins, known as nucleoside transporters (NTs), for specific transport across cell membranes. In addition to nucleosides, NTs are important determinants for the transport of nucleoside-derived drugs across cell membranes. A wide range of nucleoside-derived drugs, including anticancer drugs (such as Ara-C and gemcitabine) and antiviral drugs (such as zidovudine and ribavirin), have been shown to depend, at least in part, on NTs for transport across cell membranes. Concentrative nucleoside transporters, members of the solute carrier transporter superfamily SLC28, use an ion gradient in the active transport of both nucleosides and nucleoside-derived drugs against their chemical gradients. The structural basis for selective ion-coupled nucleoside transport by concentrative nucleoside transporters is unknown. Here we present the crystal structure of a concentrative nucleoside transporter from Vibrio cholerae in complex with uridine at 2.4 {angstrom}. Our functional data show that, like its human orthologues, the transporter uses a sodium-ion gradient for nucleoside transport. The structure reveals the overall architecture of this class of transporter, unravels the molecular determinants for nucleoside and sodium binding, and provides a framework for understanding the mechanism of nucleoside and nucleoside drug transport across cell membranes.

Johnson, Zachary Lee; Cheong, Cheom-Gil; Lee, Seok-Yong (Duke)

2012-07-11T23:59:59.000Z

305

Nanoscale study of reactive transport in catalyst layer of proton exchange membrane fuel cells with precious and non-precious catalysts using lattice Boltzmann method  

E-Print Network [OSTI]

High-resolution porous structures of catalyst layer (CL) with multicomponent in proton exchange membrane fuel cells are reconstructed using a reconstruction method called quartet structure generation set. Characterization analyses of nanoscale structures are implemented including pore size distribution, specific area and phase connectivity. Pore-scale simulation methods based on the lattice Boltzmann method are developed and used to predict the macroscopic transport properties including effective diffusivity and proton conductivity. Nonuniform distributions of ionomer in CL generates more tortuous pathway for reactant transport and greatly reduces the effective diffusivity. Tortuosity of CL is much higher than conventional Bruggeman equation adopted. Knudsen diffusion plays a significant role in oxygen diffusion and significantly reduces the effective diffusivity. Reactive transport inside the CL is also investigated. Although the reactive surface area of non-precious metal catalyst (NPMC) CL is much higher t...

Chen, Li; Kang, Qinjun; Holby, Edward F; Tao, Wen-Quan

2014-01-01T23:59:59.000Z

306

Transportation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Health Risks » Transportation Health Risks » Transportation DUF6 Health Risks line line Accidents Storage Conversion Manufacturing Disposal Transportation Transportation A discussion of health risks associated with transport of depleted UF6. Transport Regulations and Requirements In the future, it is likely that depleted uranium hexafluoride cylinders will be transported to a conversion facility. For example, it is currently anticipated that the cylinders at the ETTP Site in Oak Ridge, TN, will be transported to the Portsmouth Site, OH, for conversion. Uranium hexafluoride has been shipped safely in the United States for over 40 years by both truck and rail. Shipments of depleted UF6 would be made in accordance with all applicable transportation regulations. Shipment of depleted UF6 is regulated by the

307

Synthesis of an un-supported, high-flow ZSM-22 zeolite membrane  

DOE Patents [OSTI]

Novel methods for synthesizing wholly un-supported, high-flow catalytic membranes consisting of 100% crystalline ZSM-22 crystals with no binder phase, having sufficient porosity to allow high Weight Hourly Space Velocities of feedstock to pass through without generating back pressure. The ZSM-22 membranes perform favorably to existing bulk ZSM-22 catalysts (e.g., via 1-butene conversion and selectivity). The method of membrane synthesis, based on Vapor Phase Transport, allows free-standing, binder-less membranes to be fabricated in varied geometries and sizes so that membranes can be tailor-made for particular geometries applications. The ZSM-22 precursor gel may be consolidated into a semi-cohesive body prior to vapor phase crystallization, for example, by uniaxial pressing. These crystalline membranes may be modified by ion exchange, pore ion exchange, framework exchange, synthesis modification techniques to incorporate other elements into the framework, such as K, H, Mg, Zn, V, Ga, and Pt.

Thoma, Steven G. (Albuquerque, NM); Nenoff, Tina M. (Albuquerque, NM)

2006-10-10T23:59:59.000Z

308

Mathematical Modeling of Cation Contamination in a Proton-exchange Membrane  

SciTech Connect (OSTI)

Transport phenomena in an ion-exchange membrane containing both H+ and K+ are described using multicomponent diffusion equations (Stefan-Maxwell). A model is developed for transport through a Nafion 112 membrane in a hydrogen-pump setup. The model results are analyzed to quantify the impact of cation contamination on cell potential. It is shown that limiting current densities can result due to a decrease in proton concentration caused by the build-up of contaminant ions. An average cation concentration of 30 to 40 percent is required for appreciable effects to be noticed under typical steady-state operating conditions.

Weber, Adam; Delacourt, Charles

2008-09-11T23:59:59.000Z

309

Respiration-Linked Proton Transport, Changes in External pH, and Membrane Energization in Cells of Escherichia coli  

Science Journals Connector (OSTI)

...in untreated cells, and changing the atmosphere in the cuvette from N2 or Ar to air caused...1970. Acid-base titration across the plasma membrane of Micrococcus denitrifi- cans...of lactose-proton symport across the plasma membrane of Escherichia coli. Biochem...

J. Michael Gould

1979-04-01T23:59:59.000Z

310

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

The mechanical properties of model systems were analyzed. A reasonably accurate finite element model was implemented and a rational metric to predict the strength of ceramic/metal concentrical joints was developed. The mode of failure of the ceramic/metal joints was determined and the importance of the mechanical properties of the braze material was assessed. Thermal cycling experiments were performed on the model systems and the results were discussed. Additionally, experiments using the concept of placing diffusion barriers on the ceramic surface to limit the extent of the reaction with the braze were performed. It was also observed that the nature and morphology of the reaction zone depends greatly on the nature of the perovskite structure being used. From the experiments, it is observed that the presence of Cr in the Fe-occupied sites decreases the tendency of Fe to segregate and to precipitate out of the lattice. In these new experiments, Ni was observed to play a major role in the decomposition of the ceramic substrate.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2001-05-01T23:59:59.000Z

311

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

Conversion of natural gas to liquid fuels and chemicals is a major goal for the Nation as it enters the 21st Century. Technically robust and economically viable processes are needed to capture the value of the vast reserves of natural gas on Alaska's North Slope, and wean the Nation from dependence on foreign petroleum sources. Technologies that are emerging to fulfill this need are all based syngas as an intermediate. Syngas (a mixture of hydrogen and carbon monoxide) is a fundamental building block from which chemicals and fuels can be derived. Lower cost syngas translates directly into more cost-competitive fuels and chemicals. The currently practiced commercial technology for making syngas is either steam methane reforming (SMR) or a two-step process involving cryogenic oxygen separation followed by natural gas partial oxidation (POX). These high-energy, capital-intensive processes do not always produce syngas at a cost that makes its derivatives competitive with current petroleum-based fuels and chemicals.

Dr. Sukumar Bandopadhyay; Dr. Nagendra Nagabhushana

2002-01-01T23:59:59.000Z

312

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect (OSTI)

The mechanical properties of model systems were analyzed. A reasonably accurate finite element model was implemented and a rational metric to predict the strength of ceramic/metal concentrical joints was developed. The mode of failure of the ceramic/metal joints was determined and the importance of the mechanical properties of the braze material was assessed. Thermal cycling experiments were performed on the model systems and the results were discussed. Additionally, experiments using the concept of placing diffusion barriers on the ceramic surface to limit the extent of the reaction with the braze were performed. It was also observed that the nature and morphology of the reaction zone depends greatly on the nature of the perovskite structure being used. From the experiments, it is observed that the presence of Cr in the Fe-occupied sites decreases the tendency of Fe to segregate and to precipitate out of the lattice. In these new experiments, Ni was observed to play a major role in the decomposition of the ceramic substrate.

Dr. Sukumar Bandopadhyay; Dr. Nagendfra Nagabhushana

2001-07-01T23:59:59.000Z

313

Parametric Dependence Of Fast-ion Transport Events On The National Spherical Torus Experiment  

SciTech Connect (OSTI)

Neutral-beam heated tokamak plasmas commonly have more than one third of the plasma kinetic energy in the non-thermal energetic beam ion population. This population of fast ions heats the plasma, provides some of the current drive, and can affect the stability (positively or negatively) of magnetohydrodynamic instabilities. This population of energetic ions is not in thermodynamic equilibrium, thus there is free-energy available to drive instabilities, which may lead to redistribution of the fast ion population. Understanding under what conditions beam-driven instabilities arise, and the extent of the resulting perturbation to the fast ion population, is important for predicting and eventually demonstrating non-inductive current ramp-up and sustainment in NSTX-U, as well as the performance of future fusion plasma experiments such as ITER. This paper presents an empirical approach towards characterizing the stability boundaries for some common energetic-ion-driven instabilities seen on NSTX.

Fredrickson, Erik; Gorelenkov, N. N.; Podesta, M.; Gerhardt, S. P.; Bell, R. E.; Diallo, A.; LeBlanc, B. [Princeton Plasma Physics Lab., NJ (United States)] [Princeton Plasma Physics Lab., NJ (United States); Bortolon, A. [Univ. of Tennessee, Knoxville, TN (United States)] [Univ. of Tennessee, Knoxville, TN (United States)

2014-03-31T23:59:59.000Z

314

A gas-jet transport and catcher technique for on-line production of radioactive ion beams using an electron cyclotron resonance ion-source  

SciTech Connect (OSTI)

Radioactive ion beams (RIB) have been produced on-line, using a gas-jet recoil transport coupled Electron Cyclotron Resonance (ECR) ion-source at the VECC-RIB facility. Radioactive atoms/molecules carried through the gas-jet were stopped in a catcher placed inside the ECR plasma chamber. A skimmer has been used to remove bulk of the carrier gas at the ECR entrance. The diffusion of atoms/molecules through the catcher has been verified off-line using stable isotopes and on-line through transmission of radioactive reaction products. Beams of {sup 14}O (71 s), {sup 42}K (12.4 h), {sup 43}K (22.2 h), and {sup 41}Ar (1.8 h) have been produced by bombarding nitrogen and argon gas targets with proton and alpha particle beams from the K130 cyclotron at VECC. Typical measured intensity of RIB at the separator focal plane is found to be a few times 10{sup 3} particles per second (pps). About 3.2 Multiplication-Sign 10{sup 3} pps of 1.4 MeV {sup 14}O RIB has been measured after acceleration through a radiofrequency quadrupole linac. The details of the gas-jet coupled ECR ion-source and RIB production experiments are presented along with the plans for the future.

Naik, V.; Chakrabarti, A.; Bhattacharjee, M.; Karmakar, P.; Bandyopadhyay, A.; Dechoudhury, S.; Mondal, M.; Pandey, H. K.; Lavanyakumar, D.; Mandi, T. K.; Dutta, D. P.; Kundu Roy, T.; Bhowmick, D.; Sanyal, D.; Srivastava, S. C. L.; Ray, A.; Ali, Md. S. [Variable Energy Cyclotron Centre (VECC), Sector-1, Block-AF, Bidhan Nagar, Kolkata 700064 (India); Bhattacharjee, S. [UGC-DAE CSR, Kolkata Centre, III/LB-8, Bidhan Nagar, Kolkata 700098 (India)

2013-03-15T23:59:59.000Z

315

Solenoid transport of a heavy ion beam for warm dense matterstudies and inertial confinement fusion  

SciTech Connect (OSTI)

From February to July 2006, I have been doing research as a guest at Lawrence Berkeley National Laboratory (LBNL), in the Heavy Ion Fusion group. This internship, which counts as one semester in my master's program in France, I was very pleased to do it in a field that I consider has the beauty of fundamental physics, and at the same time the special appeal of a quest for a long-term and environmentally-respectful energy source. During my stay at LBNL, I have been involved in three projects, all of them related to Neutralized Drift Compression Experiment (NDCX). The first one, experimental and analytical, has consisted in measuring the effects of the eddy currents induced by the pulsed magnets in the conducting plates of the source and diagnostic chambers of the Solenoid Transport Experiment (STX, which is a subset of NDCX). We have modeled the effect and run finite-element simulations that have reproduced the perturbation to the field. Then, we have modified WARP, the Particle-In-Cell code used to model the whole experiment, in order to import realistic fields including the eddy current effects and some details of each magnet. The second project has been to take part in a campaign of WARP simulations of the same experiment to understand the leakage of electrons that was observed in the experiment as a consequence to some diagnostics and the failure of the electrostatic electron trap. The simulations have shown qualitative agreement with the measured phenomena, but are still in progress. The third project, rather theoretical, has been related to the upcoming target experiment of a thin aluminum foil heated by a beam to the 1-eV range. At the beginning I helped by analyzing simulations of the hydrodynamic expansion and cooling of the heated material. But, progressively, my work turned into making estimates for the nature of the liquid/vapor two-phase flow. In particular, I have been working on criteria and models to predict the formation of droplets, their size, and their partial or total evaporation in the expanding flow.

Armijo, Julien

2006-10-01T23:59:59.000Z

316

Evolution of Antiparallel Two-Domain Membrane Proteins. Swapping Domains in the Glutamate Transporter GltS  

Science Journals Connector (OSTI)

Molecular Microbiology, Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, The Netherlands ... We thank Fabrizia Fusetti of The Netherlands Proteomics Centre/Membrane Enzymology group of the University of Groningen for analyzing samples by mass spectrometry. ...

Adam Dobrowolski; Juke S. Lolkema

2010-06-17T23:59:59.000Z

317

Momentum transport in the vicinity of q{sub min} in reverse shear tokamaks due to ion temperature gradient turbulence  

SciTech Connect (OSTI)

We present an analytic study of momentum transport of tokamak plasmas in the vicinity of minimum safety factor (q) position in reversed magnetic shear configuration. Slab ion temperature gradient modes with an equilibrium flow profile are considered in this study. Quasi-linear calculations of momentum flux clearly show the novel effects of q-curvature on the generation of intrinsic rotation and mean poloidal flow without invoking reflectional symmetry breaking of parallel wavenumber (k{sub ?}). This q-curvature effect originates from the inherent asymmetry in k{sub ?} populations with respect to a rational surface due to the quadratic proportionality of k{sub ?} when q-curvature is taken into account. Discussions are made of possible implications of q-curvature induced plasma flows on internal transport barrier formation in reversed shear tokamaks.

Singh, Rameswar, E-mail: rameswar@ipr.res.in [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India) [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); Laboratoire de Physique des Plasmas, Ecole Polytechnique route de Saclay, 91128 Palaiseau Cedex (France); Singh, R [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India) [Institute for Plasma Research, Bhat, Gandhinagar 382 428 (India); WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Jhang, Hogun [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of)] [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Diamond, P. H. [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of) [WCI Center for Fusion Theory, National Fusion Research Institute, Daejeon 305-333 (Korea, Republic of); Center for Momentum Transport and Flow Organization, University of California, San Diego, California 92093 (United States); Center for Astrophysics and Space Sciences, University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0424 (United States)

2014-01-15T23:59:59.000Z

318

Convective Transport Suppression in the Scrape-Off Layer Using Ion Cyclotron Resonance Heating on the ASDEX Upgrade Tokamak  

SciTech Connect (OSTI)

Turbulence properties in the scrape-off layer (SOL) in the presence of ion cyclotron frequency heating (ICRH) are compared to instances where it is absent. The discharges are all in a high-confinement mode (H-mode) regime. During ICRH, the SOL plasma density increases whereas turbulence large-scale and convective structures are shown to be suppressed. The probability distribution function is thus recorded to be closer to a Gaussian, and a net decrease in the low-frequency density fluctuations is reflected in the power spectra. Consequently, the level of turbulent fluctuations decreases significantly. Turbulence suppression is also reported during edge localized modes (ELMs) where both the ELMs-induced transport and duration are strongly affected. The increase of neutrals by gas puffing did not alter this behavior. We deduce that ICRH can be used as to suppress convective transport and reduce the ELM's amplitude.

Antar, G. [American University of Beirut, Riad el-Solh, Beirut 1107-2020 (Lebanon); Assas, S.; Bobkov, V.; Noterdaeme, J.-M.; Wolfrum, E.; Herrmann, A.; Rohde, V. [Max-Planck Institut fuer Plasmaphysik, Boltzmannstrasse 2, 85748 Garching (Germany)

2010-10-15T23:59:59.000Z

319

Nonlinear ion concentration polarization : fundamentals and applications  

E-Print Network [OSTI]

Ion exchange membrane (IEM) is a functional material that has a permselectivity of ions. Two types of IEMs - anion exchange membrane (AEM) and cation exchange membrane (CEM) - are used in a variety of electrochemical ...

Kwak, Rhokyun

2013-01-01T23:59:59.000Z

320

Biologically inspired water purification through selective transport  

Science Journals Connector (OSTI)

Biologically inspired systems based on cellular mechanics demonstrate the ability to selectively transport ions across a bilayer membrane. These systems may be observed in nature in plant roots, which remove select nutrients from the surrounding soil against significant concentration gradients. Using biomimetic principles in the design of tailored active materials allows for the development of selective membranes for capturing and filtering targeted ions. Combining this biomimetic transport system with a method for reclaiming the captured ions will allow for increased removal potential. To illustrate this concept, a device for removing nutrients from waterways to aid in reducing eutrophication is outlined and discussed. Presented is a feasibility study of various cellular configurations designed for this purpose, focusing on maximizing nutrient uptake. The results enable a better understanding of the benefits and obstacles when developing these cellularly inspired systems.

E C Freeman; R M Soncini; L M Weiland

2013-01-01T23:59:59.000Z

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321

Argonne Transportation Technology R&D Center - About Us - DOE, Lithium-ion  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

About Us About Us Transportation Research Focuses on DOE's Energy Resources Goals Open the Door The U.S. Department of Energy's (DOE's) goals call for increasing the efficiency and productivity of energy use, while limiting the environmental impacts. In support of these goals, Argonne's Transportation Technology Research and Development Center (TTRDC) brings together scientists and engineers from many disciplines to find cost-effective solutions to the problems of foreign oil dependency and greenhouse gas emissions. As one of the DOE's lead laboratories for research in hybrid powertrains, batteries, and fuel efficient technologies, Argonne's transportation program is critical to advancing the development of next-generation vehicles. The TTRDC's overall goal is to work with DOE, other federal agencies, and industrial partners to put new transportation technologies on the road that improve the way we live and contribute to a better, cleaner future for all.

322

The Crystal Structure of OprG from Pseudomonas aeruginosa a Potential Channel for Transport of Hydrophobic Molecules across the Outer Membrane  

SciTech Connect (OSTI)

The outer membrane (OM) of Gram-negative bacteria provides a barrier to the passage of hydrophobic and hydrophilic compounds into the cell. The OM has embedded proteins that serve important functions in signal transduction and in the transport of molecules into the periplasm. The OmpW family of OM proteins, of which P. aeruginosa OprG is a member, is widespread in Gram-negative bacteria. The biological functions of OprG and other OmpW family members are still unclear. The outer membrane (OM) of Gram-negative bacteria provides a barrier to the passage of hydrophobic and hydrophilic compounds into the cell. The OM has embedded proteins that serve important functions in signal transduction and in the transport of molecules into the periplasm. The OmpW family of OM proteins, of which P. aeruginosa OprG is a member, is widespread in Gram-negative bacteria. The biological functions of OprG and other OmpW family members are still unclear. The crystal structure, together with recent biochemical data, suggests that OprG and other OmpW family members form channels that mediate the diffusion of small hydrophobic molecules across the OM by a lateral diffusion mechanism similar to that of E. coli FadL.

D Touw; D Patel; b van den Berg

2011-12-31T23:59:59.000Z

323

Electron capture and electron transport by fast ions penetrating solids: An open quantum system approach with sources and sinks  

Science Journals Connector (OSTI)

We present a joint theoretical and experimental study of the time evolution of electronic states of highly charged hydrogenic ions formed by capture during transmission through solids as they undergo multiple collisions and radiative decay. For this transport problem we have developed an inhomogeneous nonunitary Lindblad master equation that allows for a description of open quantum systems with both sinks (electron loss) and source (capture) present. We apply this theoretical framework to study transient coherences created in electron capture by 13.6MeV?amu Ar18+ ions transmitted through amorphous carbon foils and decoherence during subsequent interaction with the foil. In the limit of thin targets we can directly probe electron capture cross sections under single collision conditions, while for thicker targets we follow the partially coherent dynamics of the open quantum system in interaction with the solid as a function of interaction time. The calculated results are in close agreement with experimental data obtained at the LISE facility in GANIL. Photon intensities from excited argon ions were determined through high resolution x-ray spectroscopy in which individual fine structure components were resolved. Measurements were performed for a wide range of carbon foil thickness to study the time development of the excited state populations.

Marek Seliger; Carlos O. Reinhold; Tatsuya Minami; David R. Schultz; Michael S. Pindzola; Shuhei Yoshida; Joachim Burgdrfer; Emily Lamour; Jean-Pierre Rozet; Dominique Vernhet

2007-03-19T23:59:59.000Z

324

Triangular flow in heavy ion collisions in a multiphase transport model  

E-Print Network [OSTI]

, S. A. Bass, and B. Mu?ller, Phys. Rev. C 82, 041901 (2010). [16] B. Schenke, S. Jeon, and C. Gale, Phys. Rev. Lett. 106, 042301 (2011). [17] J. Xu and C. M. Ko, Phys. Rev. C 83, 021903(R) (2011). [18] Z. W. Lin, C. M. Ko, B. A. Li, B. Zhang... correlations in both central and midcentral collisions. DOI: 10.1103/PhysRevC.84.014903 PACS number(s): 25.75.Ld, 12.38.Mh, 24.10.Lx I. INTRODUCTION Studies of anisotropic azimuthal flows in heavy ion col- lisions at the Relativistic Heavy Ion Collider...

Xu, Jun; Ko, Che Ming.

2011-01-01T23:59:59.000Z

325

Transportation  

Science Journals Connector (OSTI)

The romantic rides in Sandburgs eagle-car changed society. On the one hand, motor vehicle transportation is an integral thread of societys fabric. On the other hand, excess mobility fractures old neighborh...

David Hafemeister

2014-01-01T23:59:59.000Z

326

THE ROLE OF CROSS-SHOCK POTENTIAL ON PICKUP ION SHOCK ACCELERATION IN THE FRAMEWORK OF FOCUSED TRANSPORT THEORY  

SciTech Connect (OSTI)

The focused transport theory is appropriate to describe the injection and acceleration of low-energy particles at shocks as an extension of diffusive shock acceleration (DSA). In this investigation, we aim to characterize the role of cross-shock potential (CSP) originated in the charge separation across the shock ramp on pickup ion (PUI) acceleration at various types of shocks with a focused transport model. The simulation results of energy spectrum and spatial density distribution for the cases with and without CSP added in the model are compared. With sufficient acceleration time, the focused transport acceleration finally falls into the DSA regime with the power-law spectral index equal to the solution of the DSA theory. The CSP can affect the shape of the spectrum segment at lower energies, but it does not change the spectral index of the final power-law spectrum at high energies. It is found that the CSP controls the injection efficiency which is the fraction of PUIs reaching the DSA regime. A stronger CSP jump results in a dramatically improved injection efficiency. Our simulation results also show that the injection efficiency of PUIs is mass-dependent, which is lower for species with a higher mass. In addition, the CSP is able to enhance the particle reflection upstream to produce a stronger intensity spike at the shock front. We conclude that the CSP is a non-negligible factor that affects the dynamics of PUIs at shocks.

Zuo, Pingbing; Zhang, Ming; Rassoul, Hamid K. [Department of Physics and Space Sciences, Florida Institute of Technology, FL 32901 (United States)

2013-10-20T23:59:59.000Z

327

BASELINE MEMBRANE SELECTION AND CHARACTERIZATION FOR AN SDE  

SciTech Connect (OSTI)

Thermochemical processes are being developed to provide global-scale quantities of hydrogen. A variant on sulfur-based thermochemical cycles is the Hybrid Sulfur (HyS) Process which uses a sulfur dioxide depolarized electrolyzer (SDE) to produce the hydrogen. In FY05 and FY06, testing at the Savannah River National Laboratory (SRNL) explored a low temperature fuel cell design concept for the SDE. The advantages of this design concept include high electrochemical efficiency and small footprint that are crucial for successful implementation on a commercial scale. A key component of the SDE is the ion conductive membrane through which protons produced at anode migrate to the cathode and react to produce hydrogen. An ideal membrane for the SDE should have both low ionic resistivity and low sulfur dioxide transport. These features allow the electrolyzer to perform at high currents with low potentials, along with preventing contamination of both the hydrogen output and poisoning of the catalysts involved. Another key component is the electrocatalyst material used for the anode and cathode. Good electrocatalysts should be chemically stable and have a low overpotential for the desired electrochemical reactions. This report summarizes results from activities to evaluate commercial and experimental membranes for the SDE. Several different types of commercially-available membranes were analyzed for sulfur dioxide transport as a function of acid strength including perfluorinated sulfonic acid (PFSA), sulfonated poly-etherketone-ketone, and poly-benzimidazole (PBI) membranes. Experimental membranes from the sulfonated diels-alder polyphenylenes (SDAPP) and modified Nafion{reg_sign} 117 were evaluated for SO{sub 2} transport as well. These membranes exhibited reduced transport coefficient for SO{sub 2} transport without the loss in ionic conductivity. The use of Nafion{reg_sign} with EW 1100 is recommended for the present SDE testing due to the limited data regarding chemical and mechanical stability of experimental membranes. Development of new composite membranes by incorporating metal particles or by forming multilayers between PFSA membranes and hydrocarbon membranes will provide methods that will meet the SDE targets (SO{sub 2} transport reduction by a factor of 100) while decreasing catalyst layer delamination and membrane resistivity.

Colon-Mercado, H; David Hobbs, D

2007-04-03T23:59:59.000Z

328

Phase Transition and Interpore Correlations of Water in Nanopore Membranes Georg Menzl,1  

E-Print Network [OSTI]

to electric fields, high flow rates, and rapid proton transport [1­4]. In biological systems, pro- tein pores spanning the cell membrane are filled with single-file water and regulate proton, ion, and water trans the behavior of nano- pore water. In this Letter, we use computer simulations to investigate such cooperative

Dellago, Christoph

329

Preliminary GYRO Studies of Momentum Transport with two Ion Species R. Budny (PPPL)  

E-Print Network [OSTI]

032844) PRINCETON PLASMA PHYSICS LABORATORY PPPL 1 #12;Assumptions for new GYRO runs · 2 ion species-Helmholtz · only electrostatic so far · both zero and reduced e PRINCETON PLASMA PHYSICS LABORATORY PPPL 2 #12;Electron density and q profiles for the JT60-U plasma · focus on region inside barrier and qmin PRINCETON

Budny, Robert

330

Unique battery with a multi-functional, physicochemically active membrane separator/electrolyte-electrode monolith and a method making the same  

DOE Patents [OSTI]

The invention relates to a unique battery having a physicochemically active membrane separator/electrolyte-electrode monolith and method of making the same. The Applicant's invented battery employs a physicochemically active membrane separator/electrolyte-electrode that acts as a separator, electrolyte, and electrode, within the same monolithic structure. The chemical composition, physical arrangement of molecules, and physical geometry of the pores play a role in the sequestration and conduction of ions. In one preferred embodiment, ions are transported via the ion-hoping mechanism where the oxygens of the Al.sub.2O.sub.3 wall are available for positive ion coordination (i.e. Li.sup.+). This active membrane-electrode composite can be adjusted to a desired level of ion conductivity by manipulating the chemical composition and structure of the pore wall to either increase or decrease ion conduction.

Gerald, II, Rex E; Ruscic, Katarina J; Sears, Devin N; Smith, Luis J; Klinger, Robert J; Rathke, Jerome W

2013-11-26T23:59:59.000Z

331

Applications of a transportable spent-fuel measurement system. [Ion-I/fork detection system  

SciTech Connect (OSTI)

A portable tool for making measurements on irradiated fuel has been developed to where in-plant installations having a 1 to 2% measurement uncertainty of relative exposure are feasible. The measurement uses a passive gross neutron signal and data from a gross gamma measurement as a consistency check of the neutron result and the operators declaration of cooling time. The uncertainties are about the same as those obtained using high-resolution gamma-ray techniques without the instrumentation being as obtrusive. The battery-operated microprocessor-based electronics package used with the irradiated fuel measurement system can also be used with single channel pulse counting detectors for other applications. This feature together with the large dynamic range of its current-mode ion chamber channel makes ION-I a good building block to be used in emergencies with an arsenal of detectors at a variety of nuclear plants. 8 figs., 3 tabs.

Halbig, J.K.; Bosler, G.E.; Klosterbuer, S.F.; Rinard, P.M.

1985-01-01T23:59:59.000Z

332

Chamber transport  

SciTech Connect (OSTI)

Heavy ion beam transport through the containment chamber plays a crucial role in all heavy ion fusion (HIF) scenarios. Here, several parameters are used to characterize the operating space for HIF beams; transport modes are assessed in relation to evolving target/accelerator requirements; results of recent relevant experiments and simulations of HIF transport are summarized; and relevant instabilities are reviewed. All transport options still exist, including (1) vacuum ballistic transport, (2) neutralized ballistic transport, and (3) channel-like transport. Presently, the European HIF program favors vacuum ballistic transport, while the US HIF program favors neutralized ballistic transport with channel-like transport as an alternate approach. Further transport research is needed to clearly guide selection of the most attractive, integrated HIF system.

OLSON,CRAIG L.

2000-05-17T23:59:59.000Z

333

Membrane resistance: The effect of salinity gradients over a cation exchange membrane  

Science Journals Connector (OSTI)

Abstract Ion exchange membranes (IEMs) are used for selective transport of ions between two solutions. These solutions are often different in concentration or composition. The membrane resistance (RM) is an important parameter affecting power consumption or power production in electrodialytic processes. In contrast to real applications, often RM is determined while using a standard 0.5M NaCl external solution. It is known that RM increases with decreasing concentration. However, the detailed effect of a salinity gradient present over an IEM on RM was not known, and is studied here using alternating and direct current. NaCl solution concentrations varied from 0.01 to 1.1M. The results show that RM is mainly determined by the lowest external concentration. RM can be considered as two resistors in series i.e. a gel phase (concentration independent) and an ionic solution phase (concentration dependent). The membrane conductivity is limited by the conductivity of the ionic solution when the external concentration, cext<0.3M. The membrane conductivity is limited by the conductivity of the gel phase when cext?0.3M, then differences of RM are small. A good approximation of experimentally determined RM can be obtained. The internal ion concentration profile is a key factor in modeling RM.

A.H. Galama; D.A. Vermaas; J. Veerman; M. Saakes; H.H.M. Rijnaarts; J.W. Post; K. Nijmeijer

2014-01-01T23:59:59.000Z

334

Argonne Transportation Technology R&D Center - Lithium-ion Batteries,  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Alternative Fuels Autonomie Batteries Downloadable Dynamometer Database Engines Green Racing GREET Hybrid Electric Vehicles Hydrogen & Fuel Cells Materials Modeling, Simulation & Software Plug-In Hybrid Electric Vehicles PSAT Smart Grid Student Competitions Technology Analysis Transportation Research and Analysis Computing Center Working With Argonne Contact TTRDC Photo of battery developers that links to story Press Coverage What's New Multimedia Logo of the Wharton School of Business Dec. 13. Knowledge@Wharton. Green SPorts and Transportation: The Elephant in the Room Logo of Crain's Chicago Business Dec. 10. Crain's Chicago Business. Argonne chemist Pete Chupas named one of Crain's 2013 "40 under 40" Logo of the Sioux City Journal Dec. 2. Sioux City Journal. Ethanol Supporters Say the Numbers Support Their Industry

335

Gas transport properties of reverse-selective poly(ether-b-amide6)/[Emim][BF4] gel membranes for CO2/light gases separation  

Science Journals Connector (OSTI)

Abstract The present research investigates deeply effect of 1-ethyl-3 methylimidazolium tetrafluoroborate ([Emim][BF4]) ionic liquid on separation performance and transport properties of poly(ether-b-amide6)(Pebax1657) at different operating pressures from 2 to 20 bar and temperatures from 25 to 65C. [Emim][BF4] showed interesting separation factor for CO2/light gases as a solvent and it was expected that its addition to Pebax1657 leads more amorphous structure, thereby diffusion and permeability of gases increase. [Emim][BF4] was added to the polymer solution up to 100 wt.% of Pebax1657 weight and permeation coefficients of CO2, H2, CH4 and N2 through the prepared membranes were measured. The results showed remarkable increment in permeation of all the tested gases, particularly CO2 and ideal selectivity of CO2/H2 enhanced significantly due to high solubility selectivity of the added compound. Effect of operating conditions on solubility coefficients were also investigated, thus sorption isotherms and activation energies of permeability, solubility and diffusion were calculated. In addition, the membranes were characterized by SEM, DSC, FT-IR spectroscopy and Tensile analysis to inspect changes in their physical and thermal properties, precisely.

Hesamoddin Rabiee; Ali Ghadimi; Toraj Mohammadi

2014-01-01T23:59:59.000Z

336

ACCELERATION OF LOW-ENERGY IONS AT PARALLEL SHOCKS WITH A FOCUSED TRANSPORT MODEL  

SciTech Connect (OSTI)

We present a test particle simulation on the injection and acceleration of low-energy suprathermal particles by parallel shocks with a focused transport model. The focused transport equation contains all necessary physics of shock acceleration, but avoids the limitation of diffusive shock acceleration (DSA) that requires a small pitch angle anisotropy. This simulation verifies that the particles with speeds of a fraction of to a few times the shock speed can indeed be directly injected and accelerated into the DSA regime by parallel shocks. At higher energies starting from a few times the shock speed, the energy spectrum of accelerated particles is a power law with the same spectral index as the solution of standard DSA theory, although the particles are highly anisotropic in the upstream region. The intensity, however, is different from that predicted by DSA theory, indicating a different level of injection efficiency. It is found that the shock strength, the injection speed, and the intensity of an electric cross-shock potential (CSP) jump can affect the injection efficiency of the low-energy particles. A stronger shock has a higher injection efficiency. In addition, if the speed of injected particles is above a few times the shock speed, the produced power-law spectrum is consistent with the prediction of standard DSA theory in both its intensity and spectrum index with an injection efficiency of 1. CSP can increase the injection efficiency through direct particle reflection back upstream, but it has little effect on the energetic particle acceleration once the speed of injected particles is beyond a few times the shock speed. This test particle simulation proves that the focused transport theory is an extension of DSA theory with the capability of predicting the efficiency of particle injection.

Zuo, Pingbing; Zhang, Ming; Rassoul, Hamid K. [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 (United States)] [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 (United States)

2013-04-10T23:59:59.000Z

337

Separation of Olefin/Paraffin Mixtures with Carrier Facilitated Membrane Final Report  

SciTech Connect (OSTI)

This document describes the results of a DOE funded joint effort of Membrane Technology and Research Inc. (MTR), SRI International (SRI), and ABB Lummus (ABB) to develop facilitated transport membranes for olefin/paraffin separations. Currently, olefin/paraffin separation is done by distillationan extremely energy-intensive process because of the low relative volatilities of olefins and paraffins. If facilitated transport membranes could be successfully commercialized, the potential energy savings achievable with this membrane technology are estimated to be 48 trillion Btu per year by the year 2020. We discovered in this work that silver salt-based facilitated transport membranes are not stable even in the presence of ideal olefin/paraffin mixtures. This decline in membrane performance appears to be caused by a previously unrecognized phenomenon that we have named olefin conditioning. As the name implies, this mechanism of performance degradation becomes operative once a membrane starts permeating olefins. This project is the first study to identify olefin conditioning as a significant factor impacting the performance of facilitated olefin transport membranes. To date, we have not identified an effective strategy to mitigate the impact of olefin conditioning. other than running at low temperatures or with low olefin feed pressures. In our opinion, this issue must be addressed before further development of facilitated olefin transport membranes can proceed. In addition to olefin conditioning, traditional carrier poisoning challenges must also be overcome. Light, hydrogen, hydrogen sulfide, and acetylene exposure adversely affect membrane performance through unwanted reaction with silver ions. Harsh poisoning tests with these species showed useful membrane lifetimes of only one week. These tests demonstrate a need to improve the stability of the olefin complexing agent to develop membranes with lifetimes satisfactory for commercial application. A successful effort to improve membrane coating solution stability resulted in the finding that membrane performance loss could be reversed for all poisoning cases except hydrogen sulfide exposure. This discovery offers the potential to extend membrane lifetime through cyclic regeneration. We also found that certain mixed carriers exhibited greater stability in reducing environments than exhibited by silver salt alone. These results offer promise that solutions to deal with carrier poisoning are possible. The main achievement of this program was the progress made in gaining a more complete understanding of the membrane stability challenges faced in the use of facilitated olefin transport membranes. Our systematic study of facilitated olefin transport uncovered the full extent of the stability challenge, including the first known identification of olefin conditioning and its impact on membrane development. We believe that significant additional fundamental research is required before facilitated olefin transport membranes are ready for industrial implementation. The best-case scenario for further development of this technology would be identification of a novel carrier that is intrinsically more stable than silver ions. If the stability problems could be largely circumvented by development of a new carrier, it would provide a clear breakthrough toward finally recognizing the potential of facilitated olefin transport. However, even if such a carrier is identified, additional development will be required to insure that the membrane matrix is a benign host for the olefin-carrier complexation reaction and shows good long-term stability.

Merkel, T.C.; Blanc, R.; Zeid, J.; Suwarlim, A.; Firat, B.; Wijmans, H.; Asaro, M. (SRI); Greene, M. (Lummus)

2007-03-12T23:59:59.000Z

338

Anion exchange membrane  

DOE Patents [OSTI]

An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

2013-05-07T23:59:59.000Z

339

Radioactive ion beam transportation for the fundamental symmetry study with laser-trapped atomsa)  

Science Journals Connector (OSTI)

The search for the violation of the fundamental symmetry in a radioactive atom is the promising candidate for precision tests of the standard model and its possible extensions. The subtle signal arising from the symmetry violation is enhanced in heavy atoms such as a francium (Fr). To realize high precision measurements a large amount of radioactive isotopes is required. The Fr is produced via a nuclear fusion reaction using a melted gold target with a 18O primary beam at Cyclotron and Radioisotope Center Tohoku University. The maximum extraction efficiency of the Fr ion was achieved at approximately 35%. The beam line consists of an electrostatic deflector three electrostatic quadrupole triplets to the measurement area at 10 m away from the reaction point and several beam diagnosis systems. We optimized parameters of the beam line.

H. Kawamura; K. Hatanaka; K. Imai

2014-01-01T23:59:59.000Z

340

A Discussion of Conductivity Testing in High Temperature Membranes...  

Broader source: Energy.gov (indexed) [DOE]

A Discussion of Conductivity Testing in High Temperature Membranes (lessons learned in assessing transport) A Discussion of Conductivity Testing in High Temperature Membranes...

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Transportation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Due to limited parking, all visitors are strongly encouraged to: Due to limited parking, all visitors are strongly encouraged to: 1) car-pool, 2) take the Lab's special conference shuttle service, or 3) take the regular off-site shuttle. If you choose to use the regular off-site shuttle bus, you will need an authorized bus pass, which can be obtained by contacting Eric Essman in advance. Transportation & Visitor Information Location and Directions to the Lab: Lawrence Berkeley National Laboratory is located in Berkeley, on the hillside directly above the campus of University of California at Berkeley. The address is One Cyclotron Road, Berkeley, California 94720. For comprehensive directions to the lab, please refer to: http://www.lbl.gov/Workplace/Transportation.html Maps and Parking Information: On Thursday and Friday, a limited number (15) of barricaded reserved parking spaces will be available for NON-LBNL Staff SNAP Collaboration Meeting participants in parking lot K1, in front of building 54 (cafeteria). On Saturday, plenty of parking spaces will be available everywhere, as it is a non-work day.

342

Recent Performance of the SNS H- ion source and low-energy beam transport system  

SciTech Connect (OSTI)

Recent measurements of the H beam current show that SNS is injecting about 55 mA into the RFQ compared to 45 mA in 2010. Since 2010, the H beam exiting the RFQ dropped from 40 mA to 34 mA, which is sufficient for 1 MW of beam power. To minimize the impact of the RFQ degradation, the service cycle of the best performing source was extended to 6 weeks. The only degradation is fluctuations in the electron dump voltage towards the end of some service cycles, a problem that is being investigated. Very recently, the RFQ was retuned, which partly restored its transmission. In addition, the electrostatic low-energy beam transport system was reengineered to double its heat sinking and equipped with a thermocouple that monitors the temperature of the ground electrode between the two Einzel lenses. The recorded data show that emissions from the source at high voltage dominate the heat load. Emissions from the partly Cs-covered first lens cause the temperature to peak several hours after starting up. On rare occasions, the temperature can also peak due to corona discharges between the center ground electrode and one of the lenses.

Stockli, Martin P [ORNL] [ORNL; Ewald, Kerry D [ORNL] [ORNL; Han, Baoxi [ORNL] [ORNL; Murray Jr, S N [ORNL] [ORNL; Pennisi, Terry R [ORNL] [ORNL; Piller, Chip [ORNL] [ORNL; Santana, Manuel [ORNL] [ORNL; Tang, Johnny Y [ORNL] [ORNL; Welton, Robert F [ORNL] [ORNL

2014-01-01T23:59:59.000Z

343

Glucose oxidase as a biocatalytic enzyme-based bio-fuel cell using Nafion membrane limiting crossover  

Science Journals Connector (OSTI)

A novel combination for an Enzyme-based Biofuel cell included a Nafion membrane as an ion transporter that maintained a working cell charge and inhibited membrane degradation. The prototype cell chamber used oxygen (O2) in the cathode cell and glucose in the anode. The Nafion membrane stability studied here was evidently in the region of 0% loss of conductivity as the charge was constant and increased after the addition of glucose. The prototype cell chamber used NaCl in the cathode cell and glucose oxidase (GOx) in the anodic chamber was successfully studied for membrane stability showed in this study no evidence of poisoning from membrane leakage in a controlled pH environment. There was no crossover at the anaerobic operating ambient temperatures and under physiological pH 5 7 conditions. In this research we have successfully used a Nafion membrane together with GOx and under controlled conditions produced respectable power densities.

S Naidoo; Q Naidoo; H Blottnitz; G Vaivars

2013-01-01T23:59:59.000Z

344

Ultrafast, Unimpeded Liquid Water Transport Through Graphene-Based Nanochannels Measured by Isotope Labelling  

E-Print Network [OSTI]

Graphene-based laminates, with ultralong and tortuous nanocapillaries formed by simply stacking graphene flakes together, have great promises in filtration and separation. However, the information on liquid water trans-membrane permeation is lacking, which is the most fundamental problem and of crucial importance in solution-based mass transport. Here, based on isotope labelling, we investigate the liquid water transportation through graphene-based nanocapillaries under no external hydrostatic pressures. Liquid water can afford an unimpeded permeation through graphene-based nanochannels with a diffusion coefficient 4~5 orders of magnitude larger than through sub-micrometer-sized polymeric channels. When dissolving ions in sources, the diffusion coefficient of ions through graphene channels lies in the same order of magnitude as water, while the ion diffusion is faster than water, indicating that the ions are mainly transported by fast water flows and the delicate interactions between ions and nanocapillary wa...

Sun, Pengzhan; Wang, Kunlin; Zhong, Minlin; Wu, Dehai; Zhu, Hongwei

2014-01-01T23:59:59.000Z

345

Rapid Ammonia Gas Transport Accounts for Futile Transmembrane Cycling under NH3/NH4  

E-Print Network [OSTI]

Rapid Ammonia Gas Transport Accounts for Futile Transmembrane Cycling under NH3/NH4 + Toxicity) seedlings is predominately of the gaseous NH3 species, rather than the NH4 + ion. Influx of 13 NH3/13 NH4 + , which exceeded 200 mmol g­1 h­1 , was not commensurate with membrane depolarization or increases in root

Britto, Dev T.

346

Ion Exclusion by Sub 2-nm Carbon Nanotube Pores  

SciTech Connect (OSTI)

Carbon nanotubes offer an outstanding platform for studying molecular transport at nanoscale, and have become promising materials for nanofluidics and membrane technology due to their unique combination of physical, chemical, mechanical, and electronic properties. In particular, both simulations and experiments have proved that fluid flow through carbon nanotubes of nanometer size diameter is exceptionally fast compared to what continuum hydrodynamic theories would predict when applied on this length scale, and also, compared to conventional membranes with pores of similar size, such as zeolites. For a variety of applications such as separation technology, molecular sensing, drug delivery, and biomimetics, selectivity is required together with fast flow. In particular, for water desalination, coupling the enhancement of the water flux with selective ion transport could drastically reduce the cost of brackish and seawater desalting. In this work, we study the ion selectivity of membranes made of aligned double-walled carbon nanotubes with sub-2 nm diameter. Negatively charged groups are introduced at the opening of the carbon nanotubes by oxygen plasma treatment. Reverse osmosis experiments coupled with capillary electrophoresis analysis of permeate and feed show significant anion and cation rejection. Ion exclusion declines by increasing ionic strength (concentration) of the feed and by lowering solution pH; also, the highest rejection is observed for the A{sub m}{sup Z{sub A}} C{sub n}{sup Z{sub C}} salts (A=anion, C=cation, z= valence) with the greatest Z{sub A}/Z{sub C} ratio. Our results strongly support a Donnan-type rejection mechanism, dominated by electrostatic interactions between fixed membrane charges and mobile ions, while steric and hydrodynamic effects appear to be less important. Comparison with commercial nanofiltration membranes for water softening reveals that our carbon nanotube membranes provides far superior water fluxes for similar ion rejection capabilities.

Fornasiero, F; Park, H G; Holt, J K; Stadermann, M; Grigoropoulos, C P; Noy, A; Bakajin, O

2008-04-09T23:59:59.000Z

347

Diffusion through Carbon Nanotube Semipermeable membranes  

SciTech Connect (OSTI)

The goal of this project is to measure transport through CNTs and study effects of confinement at molecular scale. This work is motivated by several simulation papers in high profile journals that predict significantly higher transport rates of gases and liquids through carbon nanotubes as compared with similarly-sized nanomaterials (e.g. zeolites). The predictions are based on the effects of confinement, atomically smooth pore walls and high pore density. Our work will provide the first measurements that would compare to and hopefully validate the simulations. Gas flux is predicted to be >1000X greater for SWNTs versus zeolitesi. A high flux of 6-30 H2O/NT/ns {approx} 8-40 L/min for a 1cm{sup 2} membrane is also predicted. Neutron diffraction measurements indicate existence of a 1D water chain within a cylindrical ice sheet inside carbon nanotubes, which is consistent with the predictions of the simulation. The enabling experimental platform that we are developing is a semipermeable membrane made out of vertically aligned carbon nanotubes with gaps between nanotubes filled so that the transport occurs through the nanotubes. The major challenges of this project included: (1) Growth of CNTs in the suitable vertically aligned configuration, especially the single wall carbon nanotubes; (2) Development of a process for void-free filling gaps between CNTs; and (3) Design of the experiments that will probe the small amounts of analyte that go through. Knowledge of the behavior of water upon nanometer-scale confinement is key to understanding many biological processes. For example, the protein folding process is believed to involve water confined in a hydrophobic environment. In transmembrane proteins such as aquaporins, water transport occurs under similar conditions. And in fields as far removed as oil recovery and catalysis, an understanding of the nanoscale molecular transport occurring within the nanomaterials used (e.g. zeolites) is the key to process optimization. Furthermore, advancement of many emerging nanotechnologies in chemistry and biology will undoubtedly be aided by an understanding confined water transport, particularly the details of hydrogen bonding and solvation that become crucial on this length scale. We can envision several practical applications for our devices, including desalination, gas separations, dialysis, and semipermeable fabrics for protection against CW agents etc. The single wall carbon nanotube membranes will be the key platform for applications because they will allow high transport rates of small molecules such as water and eliminate solvated ions or CW agents.

Bakajin, O

2006-02-13T23:59:59.000Z

348

Charged mosaic membrane prepared from microsphere gel and its characterization  

Science Journals Connector (OSTI)

A charged mosaic membrane with parallel array of different negative and positive charges was prepared from microsphere gel. Several characteristics on the novel membrane were investigated through experiments concerning transport studies, membrane potentials and membrane resistance. From analysis of the volume flux and salt flux, preferential salt transport across the charged mosaic membrane was suggested. Membrane potential did not indicate a constant value and the absolute value decreased rapidly in short time. The large time dependence supported the interpretation on salt flow in transport studies. From potential measurement, cationic and anionic transport numbers in membrane also were determined to t?K+=0.41 and t?Cl?=0.59. Membrane resistance of this mosaic membrane indicated slightly higher values than that of ordinary charged membrane.

Akira Yamauchi; Junko Tateyama; Ban-ichiroh Etoh; Minoru Takizawa; Yoshifumi Sugito; Seiji Doi

2000-01-01T23:59:59.000Z

349

Solid-state membrane module  

DOE Patents [OSTI]

Solid-state membrane modules comprising at least one membrane unit, where the membrane unit has a dense mixed conducting oxide layer, and at least one conduit or manifold wherein the conduit or manifold comprises a dense layer and at least one of a porous layer and a slotted layer contiguous with the dense layer. The solid-state membrane modules may be used to carry out a variety of processes including the separating of any ionizable component from a feedstream wherein such ionizable component is capable of being transported through a dense mixed conducting oxide layer of the membrane units making up the membrane modules. For ease of construction, the membrane units may be planar.

Gordon, John Howard (Salt Lake City, UT); Taylor, Dale M. (Murray, UT)

2011-06-07T23:59:59.000Z

350

Electron heat transport in the magnetic filter of a volume plasma-based source of H?/D? ions  

Science Journals Connector (OSTI)

A time-independent one-dimensional model of the electron energy balance in the region of the ... magnetic filter of a volume plasma-based ion source is justified. The local electron energy balance equation and th...

O. L. Veresov; S. V. Grigorenko; S. Yu. Udovichenko

2000-08-01T23:59:59.000Z

351

Integrated inorganic membrane electrode assembly with layered double hydroxides as ionic conductors for anion exchange membrane water electrolysis  

Science Journals Connector (OSTI)

Abstract In this work, we report a novel integrated inorganic membrane electrode assembly (I2MEA) for anion exchange membrane (AEM) water electrolysis by using inorganic Mg-Al layered double hydroxides (Mg-Al LDHs) as an ionic conductor. Mg-Al \\{LDHs\\} synthesized by a two-step approach exhibit high hydroxide ion conductivity and superior stability. The resultant ionic conducting nanoparticles are cold-pressed to form a membrane and mixed with a non-precious electrocatalyst to form the catalyst layer onto each side of the membrane. As such, an I2MEA is formed and used in a water electrolysis setup. It is shown that the present water electrolysis results in a maximum current density of 208mAcm?2 with 0.1M NaOH as the electrolyte and a cutoff voltage of 2.2V at 70C. More impressively, using 0.1M Na2CO3 as the electrolyte, the \\{I2MEAs\\} can continuously electrolyze at 80mAcm?2 for 600 hours with a decay rate of as low as 100?Vh?1. This superior stability is attributed to the integrated structure that allows hydroxide ions to transport smoothly.

L. Zeng; T.S. Zhao

2015-01-01T23:59:59.000Z

352

Membranes, methods of making membranes, and methods of separating gases using membranes  

DOE Patents [OSTI]

Membranes, methods of making membranes, and methods of separating gases using membranes are provided. The membranes can include at least one hydrophilic polymer, at least one cross-linking agent, at least one base, and at least one amino compound. The methods of separating gases using membranes can include contacting a gas stream containing at least one of CO.sub.2, H.sub.2S, and HCl with one side of a nonporous and at least one of CO.sub.2, H.sub.2S, and HCl selectively permeable membrane such that at least one of CO.sub.2, H.sub.2S, and HCl is selectively transported through the membrane.

Ho, W. S. Winston

2012-10-02T23:59:59.000Z

353

Neurotransmitter Transporters  

E-Print Network [OSTI]

at specialized synaptic junctions where electrical excitability in the form of an action potential is translated membrane of neurons and glial cells. Transporters harness electrochemical gradients to force the movement.els.net #12;The response produced when a transmitter interacts with its receptors, the synaptic potential

Bergles, Dwight

354

Folding and Function of Proteorhodopsins in Photoenergy Transducing Membranes  

SciTech Connect (OSTI)

The overall research objectives are to develop proteorhodopsin (PR) proteins as a model system for {alpha}?-helical membrane protein insertion and folding, and to advance understanding of the diversity and mechanisms of PRs, a large family of photoenergy transducers (~4000 identified) abundant in the worlds oceans. Specific aims are: (1) To develop a highefficiency genetic selection procedure for light-driven proton-pumping in E. coli cells. Such a procedure would provide a positive selection method for proper folding and function of PRs in the E. coli membrane. (2) Characterize flash-induced absorption changes and photocurrents in PR variants in organisms from various environments, and their expression level and function when expressed in E. coli. Subaims are to: (a) elucidate the relationship of the transport mechanism to mechanisms of other microbial rhodopsins, some of which like PRs function as ion transporters and some of which use light energy to activate signaling pathways (sensory rhodopsins); and (b) identify important residues and chemical events in light-driven proton transport by PRs. In addition to their importance to the energy of the biosphere PRs have attracted interest for their potential for use in making photoenergy-transducing membranes for bioengineering applications.

Spudich, John L

2012-08-10T23:59:59.000Z

355

A unified model of electroporation and molecular transport  

E-Print Network [OSTI]

Biological membranes form transient, conductive pores in response to elevated transmembrane voltage, a phenomenon termed electroporation. These pores facilitate electrical and molecular transport across cell membranes that ...

Smith, Kyle Christopher

2011-01-01T23:59:59.000Z

356

ESS 2012 Peer Review - Highly Selective Proton-Conducting Composite Membranes for Redox Flow Batteries - Alan Cisar, Lynntech  

Broader source: Energy.gov (indexed) [DOE]

Membrane for Redox Flow Batteries Membrane for Redox Flow Batteries DOE Grant No: DE-SC0004516 Alan Cisar* and Chris Rhodes Lynntech, Inc., 2501 Earl Rudder Freeway South, College Station, TX 77845 *E-mail: alan.cisar@lynntech.com, Phone: 979.764.2311 Introduction * Redox flow batteries (RFBs) are a promising technology to store electrical energy from intermittent renewable sources such as solar and wind power. Although they offer many advantages, RFBs with reduced cost and improved performance (i.e., efficiency and durability) need to be developed to achieve broad market penetration. * Ion exchange membranes in RFBs separate two soluble redox couples should allow rapid proton transport and suppress transport of the reactive species between anode and cathode compartments. Nafion

357

Minor Antenna Proteins CP24 and CP26 Affect the Interactions between Photosystem II Subunits and the Electron Transport Rate in Grana Membranes of Arabidopsis  

Science Journals Connector (OSTI)

...the grana membranes, reduced capacity for nonphotochemical quenching...reaction centers (RCs) exploit solar energy to drive electrons from...gradient for ATP synthesis. The capacity of light absorption is increased...absorbed light exceeds the capacity to use reducing equivalents...

Silvia de Bianchi; Luca Dall'Osto; Giuseppe Tognon; Tomas Morosinotto; Roberto Bassi

2008-04-01T23:59:59.000Z

358

Membrane asymmetry in epithelia: is the tight junction a barrier to diffusion in the plasma membrane?  

Science Journals Connector (OSTI)

... Leaf, A. in Membrane Transport in Biology Vol. 3 (eds Giebisch, G., Tosteson, D. C. & Ussing, H. H.) 126 (Springer, Berlin, ... Palomo, A. in Membrane Transport in Biology Vol. 3 (eds Giebisch, G., Tosteson, D. C. & Ussing H. H.) 2753 (Springer, Berlin, ...

Paul R. Dragsten; Robert Blumenthal; Joseph S. Handler

1981-12-24T23:59:59.000Z

359

Protein Flips Lipids Across Membranes  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Protein Flips Lipids Across Membranes Print Protein Flips Lipids Across Membranes Print Found ubiquitously in both bacteria and humans, membrane proteins of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter family have been implicated in both antibiotic and cancer-drug resistance. The mechanisms used by these proteins to expel toxins from cells therefore represent key targets for the development of drugs designed to combat the growing problem of multidrug resistance. Toward this end, researchers from The Scripps Research Institute have succeeded in crystallizing MsbA-an ABC transporter protein-together with a substrate (the molecule to be transported) and a hydrolyzed (spent) form of the nucleotide ATP, the transporter's source of chemical energy. The resulting molecular complex is caught at a moment following the transporter's "power stroke," the force-generating part of the transport cycle. This snapshot suggests a mechanism by which the substrate molecule gets flipped head-over-tail from one side of the membrane to the other, on its way out of the cell.

360

Protein Flips Lipids Across Membranes  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Protein Flips Lipids Across Protein Flips Lipids Across Membranes Protein Flips Lipids Across Membranes Print Wednesday, 26 October 2005 00:00 Found ubiquitously in both bacteria and humans, membrane proteins of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter family have been implicated in both antibiotic and cancer-drug resistance. The mechanisms used by these proteins to expel toxins from cells therefore represent key targets for the development of drugs designed to combat the growing problem of multidrug resistance. Toward this end, researchers from The Scripps Research Institute have succeeded in crystallizing MsbA-an ABC transporter protein-together with a substrate (the molecule to be transported) and a hydrolyzed (spent) form of the nucleotide ATP, the transporter's source of chemical energy. The resulting molecular complex is caught at a moment following the transporter's "power stroke," the force-generating part of the transport cycle. This snapshot suggests a mechanism by which the substrate molecule gets flipped head-over-tail from one side of the membrane to the other, on its way out of the cell.

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Protein Flips Lipids Across Membranes  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Protein Flips Lipids Across Membranes Print Protein Flips Lipids Across Membranes Print Found ubiquitously in both bacteria and humans, membrane proteins of the adenosine triphosphate (ATP)-binding cassette (ABC) transporter family have been implicated in both antibiotic and cancer-drug resistance. The mechanisms used by these proteins to expel toxins from cells therefore represent key targets for the development of drugs designed to combat the growing problem of multidrug resistance. Toward this end, researchers from The Scripps Research Institute have succeeded in crystallizing MsbA-an ABC transporter protein-together with a substrate (the molecule to be transported) and a hydrolyzed (spent) form of the nucleotide ATP, the transporter's source of chemical energy. The resulting molecular complex is caught at a moment following the transporter's "power stroke," the force-generating part of the transport cycle. This snapshot suggests a mechanism by which the substrate molecule gets flipped head-over-tail from one side of the membrane to the other, on its way out of the cell.

362

Isotopic tracer studies of oxygen transport through SiO2 films at 1000?C using secondary ion mass spectrometry  

Science Journals Connector (OSTI)

Dry oxides (?8 ppm H2O) grown on Si(100) at 1000?C at 1 atm using purified 1 6O2 and purified 1 8O2 were analyzed using secondary ion mass spectrometry.1 8O is observed at the interface in the bulk of the 1 6O oxide and at the surface in agreement with other recent reports. Our results show little lattice diffusion in agreement with Mikkelsens work [Appl. Phys. Lett. 4 5 1187 (1984)]. A previous report [J. Electrochem. Soc. 1 3 1 1944 (1984)] of appreciable lattice diffusion is due to higher water content.

C. J. Han; C. R. Helms

1986-01-01T23:59:59.000Z

363

Evaluation of DMDOHEMA based supported liquid membrane system for high level waste remediation under simulated conditions  

Science Journals Connector (OSTI)

Abstract N,N?-dimethyl-N,N?-dioctyl-2,(2?-hexyloxyethyl) malonamide (DMDOHEMA) has been proposed as solvent for the partitioning of radiotoxic minor actinides from high-level waste (HLW) solutions. The facilitated transport of 241Am(III), 239Pu(IV), 233U(VI), 237Np(V) across supported liquid membrane (SLM) impregnated with DMDOHEMA solution in n-dodecane was investigated under varying conditions of feed acidity, receiver phase composition, carrier concentration, and membrane thickness. Micro porous PTFE membrane was used as the polymeric support. There was a decrease in the transport of metal ions under the pressurized heavy water reactor simulated HLW (PHWR-SHLW) conditions. The physical stability of the SLM impregnated with the carrier was investigated for ~60 days by performing Am(III) permeation studies. Marginal variation in the transport behavior suggested reasonably good stability of the impregnated carrier in the membrane pores. A simple mathematical model has been developed to simulate experimental data and to explain quantitatively the role of different parameters.

Ajay B. Patil; Pankaj Kandwal; V.S. Shinde; P.N. Pathak; P.K. Mohapatra

2013-01-01T23:59:59.000Z

364

Durable, Low-cost, Improved Fuel Cell Membranes  

SciTech Connect (OSTI)

The development of low cost, durable membranes and membranes electrode assemblies (MEAs) that operate under reduced relative humidity (RH) conditions remain a critical challenge for the successful introduction of fuel cells into mass markets. It was the goal of the team lead by Arkema, Inc. to address these shortages. Thus, this project addresses the following technical barriers from the fuel cells section of the Hydrogen Fuel Cells and Infrastructure Technologies Program Multi-Year Research, Development and Demonstration Plan: (A) Durability (B) Cost Arkemas approach consisted of using blends of polyvinylidenefluoride (PVDF) and proprietary sulfonated polyelectrolytes. In the traditional approach to polyelectrolytes for proton exchange membranes (PEM), all the required properties are packaged in one macromolecule. The properties of interest include proton conductivity, mechanical properties, durability, and water/gas transport. This is the case, for example, for perfluorosulfonic acid-containing (PFSA) membranes. However, the cost of these materials is high, largely due to the complexity and the number of steps involved in their synthesis. In addition, they suffer other shortcomings such as mediocre mechanical properties and insufficient durability for some applications. The strength and originality of Arkemas approach lies in the decoupling of ion conductivity from the other requirements. Kynar PVDF provides an exceptional combination of properties that make it ideally suited for a membrane matrix (Kynar is a registered trademark of Arkema Inc.). It exhibits outstanding chemical resistance in highly oxidative and acidic environments. In work with a prior grant, a membrane known as M41 was developed by Arkema. M41 had many of the properties needed for a high performance PEM, but had a significant deficiency in conductivity at low RH. In the first phase of this work, the processing parameters of M41 were explored as a means to increase its proton conductivity. Optimizing the processing of M41 was found to increase its proton conductivity by almost an order of magnitude at 50% RH. Characterization of the membrane morphology with Karren More at Oak Ridge National Laboratory showed that the membrane morphology was complex. This technology platform was dubbed M43 and was used as a baseline in the majority of the work on the project. Although its performance was superior to M41, M43 still showed proton conductivity an order of magnitude lower than that of a PFSA membrane at 50% RH. The MEA performance of M43 could be increased by reducing the thickness from 1 to 0.6 mils. However, the performance of the thinner M43 still did not match that of a PFSA membrane.

Chris Roger; David Mountz; Wensheng He; Tao Zhang

2011-03-17T23:59:59.000Z

365

Ion Power Inc | Open Energy Information  

Open Energy Info (EERE)

Delaware Zip: 19720 Product: Manufacturer of membrane electrode assemblies (MEAs) for fuel cell and water electrolyser applications. References: Ion Power Inc1 This article...

366

Parametic Study of the current limit within a single driver-scale transport beam line of an induction Linac for Heavy Ion Fusion  

E-Print Network [OSTI]

for heavy-ion inertial fusion, Fusion Engineering and DesignIon Fusion * by Lionel Robert Prost Doctor of Philosophy in Nuclear Engineering

Prost, Lionel Robert

2007-01-01T23:59:59.000Z

367

9 - Microporous silica membranes: fundamentals and applications in membrane reactors for hydrogen separation  

Science Journals Connector (OSTI)

Abstract: This chapter discusses the research and development of membrane reactors, incorporating microporous silica-based membranes, specifically for hydrogen production. Microporous silica membranes are first introduced alongside a discussion of relevant gas transport mechanisms, membrane performance parameters, membrane reactor designs and membrane reactor performance metrics. This is followed by an in-depth analysis of the various research investigations where silica membrane reactors have been used to produce hydrogen and/or syngas from hydrocarbon reforming reactions. Of particular importance here is the hydrothermal instability of silica-based membranes at the required operating temperatures and so the chapter closes by presenting the future research trends and industrial design challenges and considerations of silica-based membrane reactors.

S. Smart; J. Beltramini; J.C. Diniz da Costa; S.P. Katikaneni; T. Pham

2013-01-01T23:59:59.000Z

368

Three-dimensional pore networks and transport properties of a shale gas formation determined from focused ion beam serial imaging  

Science Journals Connector (OSTI)

Three-dimensional pore network reconstructions of mudstone properties are made using dual focused ion beam-scanning electron microscopy (FIB-SEM). Samples of Jurassic Haynesville Formation mudstone are examined with FIB-SEM and image analysis to determine pore properties, topology, and tortuosity. Resolvable pore morphologies (>~10 nm) include large slit-like pores between clay aggregates and smaller pores in strain shadows surrounding larger clastic grains. Mercury injection capillary pressure (MICP) data suggest a dominant 1-10 nm or less size of pores barely resolvable by FIB-SEM imaging. Computational fluid dynamics modelling is used to calculate single phase permeability of the larger pore networks on the order of a few nanodarcys (which compare favourably with core-scale permeability tests). This suggests a pore hierarchy wherein permeability may be limited by connected networks of inter-aggregate pores larger than about 20 nm, while MICP results reflect smaller connected networks of pores residing in the clay matrix. [Received: May 12, 2011; Accepted: September 14, 2011

Thomas A. Dewers; Jason Heath; Russ Ewy; Luca Duranti

2012-01-01T23:59:59.000Z

369

New Proton-Ionizable, Calixarene-Based Ligands for Selective Metal Ion Separations  

SciTech Connect (OSTI)

The project objective was the discovery of new ligands for performing metal ion separations. The research effort entailed the preparation of new metal ion complexing agents and polymers and their evaluation in metal ion separation processes of solvent extraction, synthetic liquid membrane transport, and sorption. Structural variations in acyclic, cyclic, and bicyclic organic ligands were used to probe their influence upon the efficiency and selectivity with which metal ion separations can be performed. A unifying feature of the ligand structures is the presence of one (or more) side arm with a pendent acidic function. When a metal ion is complexed within the central cavity of the ligand, ionization of the side arm(s) produces the requisite anion(s) for formation of an overall electroneutral complex. This markedly enhances extraction/transport efficiency for separations in which movement of aqueous phase anions of chloride, nitrate, or sulfate into an organic medium would be required. Through systematic structural variations, new ligands have been developed for efficient and selective separations of monovalent metal ions (e.g., alkali metal, silver, and thallium cations) and of divalent metal ion species (e.g., alkaline earth metal, lead, and mercury cations). Research results obtained in these fundamental investigations provide important insight for the design and development of ligands suitable for practical metal ion separation applications.

Bartsch, Richard A.

2012-06-04T23:59:59.000Z

370

Mechanistic aspects of photoconversion at semiconductor-liquid junctions and in facilitated transport membranes. Final report, March 15, 1994--March 14, 1998  

SciTech Connect (OSTI)

A major portion of the research completed during this funding period involved the use of rotating ring-disk electrochemical techniques in conjunction with carefully chosen solution redox systems to investigate hot electron transfer reactions at the semiconductor electrolyte interface. This paper cover the following topics: photoreduction reactions at GaAs/AlGaAs superlattice electrodes; photoelectrochemistry at GaInP{sub 2} capped p-GaAs electrodes; further investigation of p-InP photocathodes; rotating ring disk photoelectrochemistry at TiO{sub 2} films; and photomodulation of interfacial mass transport rates.

Koval, C.A.

1998-06-01T23:59:59.000Z

371

FY08 MEMBRANE CHARACTERIZATION REPORT FOR HYBRID SULFUR ELECTROLYZER  

SciTech Connect (OSTI)

This report summarizes results from all of the membrane testing completed to date at the Savannah River National Laboratory (SRNL) for the sulfur dioxide-depolarized electrolyzer (SDE). Several types of commercially-available membranes have been analyzed for ionic resistance and sulfur dioxide transport including perfluorinated sulfonic acid (PFSA), sulfonated polyether-ketone-ketone (SPEKK), and polybenzimidazole membranes (PBI). Of these membrane types, the poly-benzimidazole membrane, Celtec-L, exhibited the best combination of characteristics for use in an SDE. Several experimental membranes have also been analyzed including hydrated sulfonated Diels-Alder polyphenylenes (SDAPP) membranes from Sandia National Laboratory, perfluorosulfonimide (PFSI) and sulfonated perfluorocyclobutyl aromatic ether (S-PFCB) prepared by Clemson University, hydrated platinum-treated PFSA prepared by Giner Electrochemical Systems (GES) and Pt-Nafion{reg_sign} 115 composites prepared at SRNL. The chemical stability, SO{sub 2} transport and ionic conductivity characteristics have been measured for several commercially available and experimental proton-conducting membranes. Commercially available PFSA membranes such as the Nafion{reg_sign} series exhibited excellent chemical stability and ionic conductivity in sulfur dioxide saturated sulfuric acid solutions. Sulfur dioxide transport in the Nafion{reg_sign} membranes varied proportionally with the thickness and equivalent weight of the membrane. Although the SO{sub 2} transport in the Nafion{reg_sign} membranes is higher than desired, the excellent chemical stability and conductivity makes this membrane the best commercially-available membrane at this time. Initial results indicated that a modified Nafion{reg_sign} membrane incorporating Pt nanoparticles exhibited significantly reduced SO{sub 2} transport. Reduced SO{sub 2} transport was also measured with commercially available PBI membrane and several experimental membranes produced at SNL and Clemson. These membranes also exhibit good chemical stability and conductivity in concentrated sulfuric acid solutions and, thus, serve as promising candidates for the SDE. Therefore, we recommend further testing of these membranes including electrolyzer testing to determine if the reduced SO{sub 2} transport eliminates the formation of sulfur-containing films at the membrane/cathode interface. SO{sub 2} transport measurements in the custom built characterization cell identified experimental limitations of the original design. During the last quarter of FY08 we redesigned and fabricated a new testing cell to overcome the previous limitations. This cell also offers the capability to test membranes under polarized conditions as well as test the performance of MEAs under selected electrolyzer conditions.

Hobbs, D; Hector Colon-Mercado, H; Mark Elvington, M

2008-09-01T23:59:59.000Z

372

Energy transport in the solar transition layer  

Science Journals Connector (OSTI)

...research-article Research Article Energy transport in the solar transition layer J...emission measure in the solar transition layer, which...the heat transport. solar transition layer|differential emission measure|energy transport|ion-acoustic...

2001-01-01T23:59:59.000Z

373

Ionically Conducting Membranes for Hydrogen Production and Separation  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

IONICALLY CONDUCTING MEMBRANES IONICALLY CONDUCTING MEMBRANES FOR HYDROGEN PRODUCTION AND SEPARATION Presented by Tony Sammells Eltron Research Inc. Boulder, Colorado www.eltronresearch.com Presented at DOE Hydrogen Separations Workshop Arlington, Virginia September 8, 2004 ELTRON RESEARCH INC. TO BE DISCUSSED * Membranes for Hydrogen Production - Compositions - Feedstocks - Performance - Key Technical Hurdles * Membranes for Hydrogen Separation - Compositions - Ex Situ vs. In Situ WGS - Performance - Key Technical Hurdles ELTRON RESEARCH INC. OVERALL SCHEME FOR CONVERTING FEEDSTOCK TO HYDROGEN WITH SIMULTANEOUS CARBON DIOXIDE SEQUESTRATION Oxygen Transport Membrane Hydrogen Transport Membrane Natural Gas Coal Biomass Syngas CO/H 2 WGS H 2 O CO 2 /H 2 1618afs.dsf H 2 CO 2 ELTRON RESEARCH INC. INCENTIVES FOR OXYGEN TRANSPORT MEMBRANES FOR

374

Membrane magic  

SciTech Connect (OSTI)

The Kansas Power and Light Co.'s La Cyne generating station has found success with membrane filtration water pretreatment technology. The article recounts the process followed in late 2004 to install a Pall Aria 4 microfilter in Unit 1 makeup water system at the plant to produce cleaner water for reverse osmosis feed. 2 figs., 2 photos.

Buecker, B. [Kansas City Power and Light Co. (United States)

2005-09-01T23:59:59.000Z

375

COMBUSTION-ASSISTED CO2 CAPTURE USING MECC MEMBRANES  

SciTech Connect (OSTI)

Mixed Electron and Carbonate ion Conductor (MECC) membranes have been proposed as a means to separate CO{sub 2} from power plant flue gas. Here a modified MECC CO{sub 2} capture process is analyzed that supplements retentate pressurization and permeate evacuation as a means to create a CO{sub 2} driving force with a process assisted by the catalytic combustion of syngas on the permeate side of the membrane. The combustion reactions consume transported oxygen, making it unavailable for the backwards transport reaction. With this change, the MECC capture system becomes exothermic, and steam for electricity production may be generated from the waste heat. Greater than 90% of the CO{sub 2} in the flue gas may be captured, and a compressed CO{sub 2} product stream is produced. A fossil-fueled power plant using this process would consume 14% more fuel per unit electricity produced than a power plant with no CO{sub 2} capture system, and has the potential to meet U.S. DOE's goal that deployment of a CO{sub 2} capture system at a fossil-fueled power plant should not increase the cost of electricity from the combined facility by more than 30%.

Brinkman, K.; Gray, J.

2012-03-30T23:59:59.000Z

376

Combustion-Assisted CO2 Capture Using MECC Membranes  

SciTech Connect (OSTI)

Mixed Electron and Carbonate ion Conductor (MECC) membranes have been proposed as a means to separate CO2 from power plant flue gas. Here a modified MECC CO2 capture process is analyzed that supplements retentate pressurization and permeate evacuation as a means to create a CO2 driving force with a process assisted by the catalytic combustion of syngas on the permeate side of the membrane. The combustion reactions consume transported oxygen, making it unavailable for the backwards transport reaction. With this change, the MECC capture system becomes exothermic, and steam for electricity production may be generated from the waste heat. Greater than 90% of the CO2 in the flue gas may be captured, and a compressed CO2 product stream is produced. A fossil-fueled power plant using this process would consume 14% more fuel per unit electricity produced than a power plant with no CO2 capture system, and has the potential to meet U.S. DOE s goal that deployment of a CO2 capture system at a fossil-fueled power plant should not increase the cost of electricity from the combined facility by more than 30%.

Sherman, Steven R [ORNL; Gray, Dr. Joshua R. [Savannah River National Laboratory (SRNL), Aiken, S.C.; Brinkman, Dr. Kyle S. [Savannah River National Laboratory (SRNL), Aiken, S.C.; Huang, Dr. Kevin [University of South Carolina, Columbia

2012-01-01T23:59:59.000Z

377

Dual Phase Membrane for High Temperature CO2 Separation  

SciTech Connect (OSTI)

This project aimed at synthesis of a new inorganic dual-phase carbonate membrane for high temperature CO{sub 2} separation. Metal-carbonate dual-phase membranes were prepared by the direct infiltration method and the synthesis conditions were optimized. Permeation tests for CO{sub 2} and N{sub 2} from 450-750 C showed very low permeances of those two gases through the dual-phase membrane, which was expected due to the lack of ionization of those two particular gases. Permeance of the CO{sub 2} and O{sub 2} mixture was much higher, indicating that the gases do form an ionic species, CO{sub 3}{sup 2-}, enhancing transport through the membrane. However, at temperatures in excess of 650 C, the permeance of CO{sub 3}{sup 2-} decreased rapidly, while predictions showed that permeance should have continued to increase with temperature. XRD data obtained from used membrane indicated that lithium iron oxides formed on the support surface. This lithium iron oxide layer has a very low conductivity, which drastically reduces the flow of electrons to the CO{sub 2}/O{sub 2} gas mixture; thus limiting the formation of the ionic species required for transport through the membrane. These results indicated that the use of stainless steel supports in a high temperature oxidative environment can lead to decreased performance of the membranes. This revelation created the need for an oxidation resistant support, which could be gained by the use of a ceramic-type membrane. Work was extended to synthesize a new inorganic dual-phase carbonate membrane for high temperature CO{sub 2} separation. Helium permeance of the support before and after infiltration of molten carbonate are on the order of 10{sup -6} and 10{sup -10} moles/m{sup 2} {center_dot} Pa {center_dot} s respectively, indicating that the molten carbonate is able to sufficiently infiltrate the membrane. It was found that La{sub 0.6}Sr{sub 0.4}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}} (LSCF) was a suitable candidate for the support material. This support material proved to separate CO{sub 2} when combined with O{sub 2} at a flux of 0.194 ml/min {center_dot} cm{sup 2} at 850 C. It was also observed that, because LSCF is a mixed conductor (conductor of both electrons and oxygen ions), the support was able to provide its own oxygen to facilitate separation of CO{sub 2}. Without feeding O{sub 2}, the LSCF dual phase membrane produced a maximum CO{sub 2} flux of 0.246 ml/min {center_dot} cm{sup 2} at 900 C.

Jerry Lin

2007-06-30T23:59:59.000Z

378

This article was downloaded by:[Smith, Bradley] [Smith, Bradley  

E-Print Network [OSTI]

. Keywords: Membrane transport; Ionosphere; Ion channel; Mobile carrier; Membrane pore; Self the permeability of small polar molecules and inorganic ions. Controlled ion transport across membranes and W. Matthew Leevy , 'Recent Advances in Synthetic Membrane Transporters', Supramolecular Chemistry

Smith, Bradley D.

379

Targeting ion transport in cancer  

Science Journals Connector (OSTI)

...tumor hypoxia, survival pathway and therapy target. Cell Cycle 3, 164-167. ( doi:10.4161/cc.3.2.618 ) 73 Rademakers, SE , Lok, J, van der Kogel, AJ, Bussink, J, Kaanders, JH. 2011 Metabolic markers in relation to hypoxia; staining...

2014-01-01T23:59:59.000Z

380

Material properties of cation exchange membranes for chloralkali electrolysis, water electrolysis and fuel cells  

Science Journals Connector (OSTI)

Owing to the development of perfluorinated ion-exchange membranes, the application of the membranes in electrochemical cells has advanced greatly, especially in chloralkali electrolysis. Material properties of pe...

T. Asawa

1989-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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381

Parametic Study of the current limit within a single driver-scale transport beam line of an induction Linac for Heavy Ion Fusion  

E-Print Network [OSTI]

to controlled thermonuclear fusion which uses intense ion orto controlled thermonuclear fusion energy to commercialFusion Energy (MFE) is the approach to controlled thermonuclear

Prost, Lionel Robert

2007-01-01T23:59:59.000Z

382

Parametic Study of the current limit within a single driver-scale transport beam line of an induction Linac for Heavy Ion Fusion  

E-Print Network [OSTI]

Physics of Magnetic Fusion Reactors, Rev. of Modern Physicsheavy ion beam driven fusion reactor study, Technical Reporta toroidally shaped fusion reactor (tokamak) such as shown

Prost, Lionel Robert

2007-01-01T23:59:59.000Z

383

E-Print Network 3.0 - abc transporter mutants Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

THE ABC TRANSPORTER SUPERFAMILY Summary: -association of point mutants. 1. Introduction ATP-binding cassette (ABC) transporters are membrane-spanning proteins... -associated...

384

Ion channels and apoptosis in cancer  

Science Journals Connector (OSTI)

...Issue Ion channels, transporters and cancer compiled and edited by Mustafa B. A...Albrecht Schwab Ion channels and apoptosis in cancer Carl D. Bortner John A. Cidlowski e-mail...Issue Ion channels, transporters and cancer . Humans maintain a constant cell number...

2014-01-01T23:59:59.000Z

385

Lithium Source For High Performance Li-ion Cells  

Broader source: Energy.gov (indexed) [DOE]

New cathode and anode electrodes are required to improve the energy density of Li-ion cells for transportation technologies. The cost of Li-ion systems for transportation...

386

Evaluation of synthetic salt water desalination by using a functionalized polysulfone based bipolar membrane electrodialysis cell  

Science Journals Connector (OSTI)

Abstract The work reported herein describes the study of desalination of synthetic salt water at laboratory scale in five different feed concentrations using a lab-made functionalized high molecular weight polysulfone (PSu) polymer based monopolar (cation exchange and anion exchange) and bipolar ion exchange membranes (with PVA as the intermediate layer) using bipolar membrane electrodialysis cell. Various parameters such as conductivity, solution pH, feed concentration, current efficiency, energy consumption, transport number, fluxes and water dissociation efficiency were determined. During the 8h treatment under optimal conditions (i.e. time, current, higher acid and base concentrations), for the various initial feed concentrations (from 10g/L to 50g/L), the current efficiencies obtained ranged from 27% to 75%. And for the highest feed concentration, the highest current efficiency (?max. of about 75% for \\{PSu\\} and 63% for polystyrene divinylbenzene (PSDVB)) with lowest energy consumption (?max. of about 1.2Wh/mol for \\{PSu\\} and 2.6Wh/mol for PSDVB) in addition to acid-base production (?max. of about 0.018N acid: 0.016N base for \\{PSu\\} and 0.012N acid: 0.013N base for PSDVB) was observed. The results of the study demonstrated the promising potential of functionalized polysulfone based ion exchange membranes for greater water dissociation efficiency in desalination of water.

Krishnaveni Venugopal; Sangeetha Dharmalingam

2014-01-01T23:59:59.000Z

387

Membrane technology works on North Sea platform  

SciTech Connect (OSTI)

The world`s first sulfate removal facility (SRF) on the Brae A production platform in the central North Sea demonstrates the effectiveness of membrane technology with only a few minor problems caused by the retrofit nature of the installation. This is the second in a three-part series that details experiences with membrane technology on the Brae A platform that future users of this membrane technology can use for optimizing their SRF installations. Formation water in the south and central Brae reservoirs contains very high levels of barium ions. Consequently, there is a high potential for forming barium sulfate scale when Brae formation water is mixed with seawater. Because of high levels of barium, conventional methods for preventing barium sulfate scale with chemical scale inhibitors proved difficult and expensive, and are of limited value for protecting the reservoir matrix. Therefore, the Brae field required a process that could selectively remove sulfate ions from seawater yet retain most other salt components. Reverse osmosis appeared to be one option, and subsequent collaboration with FilmTec identified a membrane that would only pass particles of 1 x 10{sup {minus}9} m (nanofiltration) and smaller. This membrane permitted passage of most sodium and chloride ions but let only a small percentage of sulfate ions through.

O`Donnell, K. [Marathon Oil UK Ltd., Aberdeen (United Kingdom)

1996-12-02T23:59:59.000Z

388

ESS 2012 Peer Review - Flow Battery Membrane - David Ofer, Tiax  

Broader source: Energy.gov (indexed) [DOE]

Flow Battery Membrane Flow Battery Membrane Energy Storage Systems Program (ESS) Peer Review and Update Meeting 2012 Jack Treger treger.jack@tiaxllc.com Washington DC, September 27, 2012 Flow Battery Membrane Background and Purpose 1 Vanadium redox batteries (VRB) for energy storage require improved ion- selective membranes. * Vanadium permeation across current membranes leads to self-discharge and decreases cycling efficiency: - Negative half cell: V 2+ V 3+ + e - E o = -0.255V - Positive half cell: e - + VO 2 + + 2H + VO 2+ + H 2 O E o = 1.00V . * Current perfluorosulfonic acid polymer membranes are costly. * TIAX is developing a novel composite bipolar membrane: - Composite anionic membrane minimizes content of costly perfluorosulfonic acid polymer - Made bipolar by a cationic surface layer to improve selectivity for

389

Wastewater treatment of phosphate ions by the electrodialysis method  

Science Journals Connector (OSTI)

The chemical composition of wastewater at the Turkmenabad chemical enterprise and the possibility of its treatment has been studied. The transfer of phosphate-ions through standard ion-permeable membranes was ...

Sh. Ch. Akyeva; L. K. Berkelieva

2008-08-01T23:59:59.000Z

390

A New Hybrid Proton-Exchange-Membrane Fuel Cells-Battery Power System with Efficiencies Considered  

Science Journals Connector (OSTI)

Hybrid systems, based on lead-acid or lithium-ion batteries and proton-exchange-membrane fuel cells (PEMFCs), give the possibility of ... results show that the combination of lead-acid batteries or lithium-ion batteries

Chung-Hsing Chao; Jenn-Jong Shieh

2013-01-01T23:59:59.000Z

391

Membrane-patch Excision  

Science Journals Connector (OSTI)

Mechanical manipulation of the cell using glass micropipettes that leads to the extraction of a narrow region of cell membrane. The excision can lead to an isolated membrane patch in which the side of the membran...

2009-01-01T23:59:59.000Z

392

Electrodialysis of vanadium(III) and iron(II) ions from a simulated decontamination solution  

SciTech Connect (OSTI)

The transport of vanadium(III) and iron(II) ions through the Nafion 117 cation-exchange membrane in the presence of picolinic acid was investigated by simulating the equilibrium distribution of ionic species as a function of pH, and by electrodialyzing the simulated waste solution. From distribution calculations of the model reaction systems it could be predicted that at pH 1.6 most vanadium ions exist predominantly in the form of the V{sup III}(Pic{sup {minus}}){sub 2}{sup +} complex, and this form of complex permeates across the cation-exchange membrane during electrodialysis. The experimental results, including variations in the color and cation concentrations of the catholyte, confirm the existence of the vanadium(III) picolinate complex. Iron ions permeated into the catholyte were converted to their hydroxide precipitates, which could be formed at the high pH condition resulting from the reduction of hydrogen ions and the production of OH{sup {minus}} ions by water electrolysis at the cathode. It was also found that the in-situ precipitation of iron in the electrodialyzer could be self-modulated by shifting the catholyte pH from the acidic state to the alkaline state during electrodialysis operation.

Shim, J.B.; Oh, W.Z.; Lee, B.J.; Park, H.S. [Korea Atomic Energy Research Inst., Taejon (Korea, Republic of)] [Korea Atomic Energy Research Inst., Taejon (Korea, Republic of); Kim, J.D. [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Chemical Engineering] [Korea Advanced Inst. of Science and Technology, Taejon (Korea, Republic of). Dept. of Chemical Engineering

1999-07-01T23:59:59.000Z

393

Membrane cleaning in membrane bioreactors: A review  

Science Journals Connector (OSTI)

Abstract Membrane bioreactors (MBRs) have been widely used in wastewater treatment and reclamation. Membrane cleaning is an essential part during the operation of \\{MBRs\\} since membrane fouling is an unavoidable problem. In past decades, with the in-depth understanding on membrane fouling, significant advances in membrane cleaning have been achieved. However, a comprehensive review on membrane cleaning in \\{MBRs\\} is still lacking. This paper attempts to critically review the recent developments of membrane cleaning. Firstly, the fouling and cleaning fundamentals are addressed, and then a comprehensive review on physical, chemical, and biological/biochemical cleaning is presented. The procedures of determining proper cleaning protocols for MBR systems are also proposed. Finally, the existing challenges and future research efforts are discussed in order to ensure the development of membrane cleaning toward a more effective and sustainable way in MBRs.

Zhiwei Wang; Jinxing Ma; Chuyang Y. Tang; Katsuki Kimura; Qiaoying Wang; Xiaomeng Han

2014-01-01T23:59:59.000Z

394

Alternate Fuel Cell Membranes for Energy Independence  

SciTech Connect (OSTI)

The overall objective of this project was the development and evaluation of novel hydrocarbon fuel cell (FC) membranes that possess high temperature performance and long term chemical/mechanical durability in proton exchange membrane (PEM) fuel cells (FC). The major research theme was synthesis of aromatic hydrocarbon polymers of the poly(arylene ether sulfone) (PAES) type containing sulfonic acid groups tethered to the backbone via perfluorinated alkylene linkages and in some cases also directly attached to the phenylene groups along the backbone. Other research themes were the use of nitrogen-based heterocyclics instead of acid groups for proton conduction, which provides high temperature, low relative humidity membranes with high mechanical/thermal/chemical stability and pendant moieties that exhibit high proton conductivities in the absence of water, and synthesis of block copolymers consisting of a proton conducting block coupled to poly(perfluorinated propylene oxide) (PFPO) blocks. Accomplishments of the project were as follows: 1) establishment of a vertically integrated program of synthesis, characterization, and evaluation of FC membranes, 2) establishment of benchmark membrane performance data based on Nafion for comparison to experimental membrane performance, 3) development of a new perfluoroalkyl sulfonate monomer, N,N-diisopropylethylammonium 2,2-bis(p-hydroxyphenyl) pentafluoropropanesulfonate (HPPS), 4) synthesis of random and block copolymer membranes from HPPS, 5) synthesis of block copolymer membranes containing high-acid-concentration hydrophilic blocks consisting of HPPS and 3,3'-disulfonate-4,4'-dichlorodiphenylsulfone (sDCDPS), 6) development of synthetic routes to aromatic polymer backbones containing pendent 1H-1,2,3-triazole moieties, 7) development of coupling strategies to create phase-separated block copolymers between hydrophilic sulfonated prepolymers and commodity polymers such as PFPO, 8) establishment of basic performance properties of experimental membranes, 9) fabrication and FC performance testing of membrane electrode assemblies (MEA) from experimental membranes, and 10) measurement of ex situ and in situ membrane durability of experimental membranes. Although none of the experimental hydrocarbon membranes that issued from the project displayed proton conductivities that met DOE requirements, the project contributed to our basic understanding of membrane structure-property relationships in a number of key respects. An important finding of the benchmark studies is that physical degradation associated with humidity and temperature variations in the FC tend to open new fuel crossover pathways and act synergistically with chemical degradation to accelerate overall membrane degradation. Thus, for long term membrane survival and efficient fuel utilization, membranes must withstand internal stresses due to humidity and temperature changes. In this respect, rigid aromatic hydrocarbon fuel cell membranes, e.g. PAES, offer an advantage over un-modified Nafion membranes. The benchmark studies also showed that broadband dielectric spectroscopy is a potentially powerful tool in assessing shifts in the fundamental macromolecular dynamics caused by Nafion chemical degradation, and thus, this technique is of relevance in interrogating proton exchange membrane durability in fuel cells and macromolecular dynamics as coupled to proton migration, which is of fundamental relevance in proton exchange membranes in fuel cells. A key finding from the hydrocarbon membrane synthesis effort was that rigid aromatic polymers containing isolated ion exchange groups tethered tightly to the backbone (short tether), such as HPPS, provide excellent mechanical and durability properties but do not provide sufficient conductivity, in either random or block configuration, when used as the sole ion exchange monomer. However, we continue to hypothesize that longer tethers, and tethered groups spaced more closely within the hydrophilic chain elements of the polymer, will yield highly conductive materials with excellent mech

Storey, Robson, F.; Mauritz, Kenneth, A.; Patton, Derek, L.; Savin, Daniel, A.

2012-12-18T23:59:59.000Z

395

Membranes for corrosive oxidations. Final CRADA report.  

SciTech Connect (OSTI)

The objective of this project is to develop porous hydrophilic membranes that are highly resistant to oxidative and corrosive conditions and to deploy them for recovery and purification of high tonnage chemicals such as hydrogen peroxide and other oxychemicals. The research team patented a process for membrane-based separation of hydrogen peroxide (US Patent No. 5,662,878). The process is based on using a hydrophilic membrane to separate hydrogen peroxide from the organic working solution. To enable this process, a new method for producing hydrophilic membrane materials (Patent No.6,464,880) was reported. We investigated methods of producing these hydrophilic materials and evaluated separations performance in comparison to membrane stability. It was determined that at the required membrane flux, membrane stability was not sufficient to design a commercial process. This work was published (Hestekin et al., J. Membrane Science 2006). To meet the performance needs of the process, we developed a membrane contactor method to extract the hydrogen peroxide, then we surveyed several commercial and pre-commercial membrane materials. We identified pre-commercial hydrophilic membranes with the required selectivity, flux, and stability to meet the needs of the process. In addition, we invented a novel reaction/separations format that greatly increases the performance of the process. To test the performance of the membranes and the new formats we procured and integrated reactor/membrane separations unit that enables controlled mixing, flow, temperature control, pressure control, and sampling. The results were used to file a US non-provisional patent application (ANL-INV 03-12). Hydrogen peroxide is widely used in pulp and paper applications, environmental treatment, and other industries. Virtually all hydrogen peroxide production is now based on a process featuring catalytic hydrogenation followed by auto-oxidation of suitable organic carrier molecules. This process has several drawbacks, particularly in the extraction phase. One general disadvantage of this technology is that hydrogen peroxide must be produced at large centralized plants where it is concentrated to 70% by distillation and transported to the users plant sites where it is diluted before use. Advanced membranes have the potential to enable more efficient, economic, and safe manufacture of hydrogen peroxide. Advanced membrane technology would allow filtration-based separation to replace the difficult liquid-liquid extraction based separation step of the hydrogen peroxide process. This would make it possible for hydrogen peroxide to be produced on-site in mini-plants at 30% concentration and used at the same plant location without distillation and transportation. As a result, production could become more cost-effective, safe and energy efficient.

Snyder, S. W.; Energy Systems

2010-02-01T23:59:59.000Z

396

Microcomposite Fuel Cell Membranes  

Broader source: Energy.gov [DOE]

Summary of microcomposite fuel cell membrane work presented to the High Temperature Membrane Working Group Meeting, Orlando FL, October 17, 2003

397

Membrane-Transistor Cable  

Science Journals Connector (OSTI)

Membrane-Transistor Cable ... The system is the basis for a development of bioelectronic transducers and for the study of nonlinear phenomena in membrane cables. ...

Marion Rentschler; Peter Fromherz

1998-01-20T23:59:59.000Z

398

The Effect of temperature gradient on the transport phenomenon in roots of maize plants grown under salinity conditions. substance, heat, and ion flows  

Science Journals Connector (OSTI)

The accumulation of nitrogen and potassium by plant cells at undesirable concentrations manifests itself in changes in the osmotic phenomenon and finally in the transport process. Temperature gradient is another ...

J. Michalov

1989-07-01T23:59:59.000Z

399

Unique Thylakoid Membrane Architecture of aUnicellular N2-Fixing...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

intracellular transport and trafficking. Citation: Liberton ML, JR Austin, RH Berg, and HB Pakrasi.2011."Unique Thylakoid Membrane Architecture of aUnicellular N2-Fixing...

400

Amino acids evoke short-latency membrane conductance increase in pancreatic acinar cells  

Science Journals Connector (OSTI)

... K. J. in Membrane Transport in Biology Vol. IV (eds Giebisch, G., Tosteson, D. C. & Ussing, H. H.) 811852 (Springer, Berlin, ...

N. Iwatsuki; O. H. Petersen

1980-01-31T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

E-Print Network 3.0 - anion selective membrane Sample Search...  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

potential... Development of synthetic membrane transporters for anions ... Source: Smith, Bradley D. - Department of Chemistry and Biochemistry, University of Notre Dame...

402

High performance and antifouling vertically aligned carbon nanotube membrane for water purification  

Science Journals Connector (OSTI)

Abstract A vertically aligned carbon nanotube (VA CNT) membrane created from the successful fusion of nanotechnology and membrane technology has been stated to be a next generation membrane due to its fast water transport and antimicrobial properties. Although previous studies of the VA CNT membrane reported the potential for fast water transport or desalination by molecular dynamics simulation, this study is the first to report on the feasibility of using the VA CNT membrane for water purification. The VA CNT membrane (4.8nm of pore diameter and 6.81010#/cm2 of pore density) was fabricated and its flux, rejection performance, and membrane biofouling tendency were evaluated in comparison to the commercial ultrafiltration (UF) membrane. The VA CNT membrane appeared to have a water flux approximately three times higher than the UF membrane and water transport approximately 70,000 times faster than conventional no-slip flow. This higher flux was peculiarly observed in water, the most hydrophilic solvent, while other solvents showed that permeate flux decreased with higher viscosity. The rejection property of the VA CNT membrane as examined by the MWCO measurement was similar to the commercial UF membrane. Additionally, the VA CNT membrane showed better biofouling resistance with approximately 15% less permeate flux reduction and 2log less bacterial attachment than the UF membrane. This study reports the high potential of the VA CNT membrane with antifouling property in the water purification process.

Youngbin Baek; Cholin Kim; Dong Kyun Seo; Taewoo Kim; Jeong Seok Lee; Yong Hyup Kim; Kyung Hyun Ahn; Sang Seek Bae; Sang Cheol Lee; Jaelim Lim; Kyunghyuk Lee; Jeyong Yoon

2014-01-01T23:59:59.000Z

403

A Mechanistic Study of Chemically Modified Inorganic Membranes for Gas and Liquid Separations  

SciTech Connect (OSTI)

This final report will summarize the progress made during the period August 1, 1993 - October 31, 2010 with support from DOE grant number DE-FG03-93ER14363. The objectives of the research have been to investigate the transport mechanisms in micro- and mesoporous, metal oxide membranes and to examine the relationship between the microstructure of the membrane, the membrane surface chemistry, and the separation performance of the membrane. Examples of the membrane materials under investigation are the microporous silica hollow fiber membrane manufactured by PPG Industries, chemically modified mesoporous oxide membranes, and polymer membranes containing microporous oxides (mixed matrix membranes). Analytical techniques such as NMR, FTIR and Raman spectroscopy, thermal analysis, and gas adsorption were used to investigate membrane microstructure and to probe the chemical interactions occurring at the gas-membrane interface.

Way, J Douglas

2011-01-21T23:59:59.000Z

404

Self-Induced Docking Site of a Deeply Embedded Peripheral Membrane Protein  

E-Print Network [OSTI]

paramagnetic resonance (EPR). Noting that in the membrane-bound state the three calcium binding loops features: an eight-strand antiparallel b-sandwich, and three negatively charged calcium-binding loops (CBLs are complexed to two calcium ions, we initially restrained the calcium ions at the membrane depth determined

White, Stephen

405

Membrane Biophysics and Mechanics in Alzheimer's Disease Xiaoguang Yang & Sholpan Askarova & James C-M. Lee  

E-Print Network [OSTI]

-assemble into large, voltage-independent, and nonselective ion channels at cell membranes. A can also perturb.-M. Lee (*) Department of Biological Engineering, University of Missouri, 240 Agricultural Engineering and the formation of ion channel and neurotoxicity [24, 25]. There are two types of A­membrane interactions

Lee, James

406

Ligand-gated Diffusion Across the Bacterial Outer Membrane  

SciTech Connect (OSTI)

Ligand-gated channels, in which a substrate transport pathway is formed as a result of the binding of a small-molecule chemical messenger, constitute a diverse class of membrane proteins with important functions in prokaryotic and eukaryotic organisms. Despite their widespread nature, no ligand-gated channels have yet been found within the outer membrane (OM) of Gram-negative bacteria. Here we show, using in vivo transport assays, intrinsic tryptophan fluorescence and X-ray crystallography, that high-affinity (submicromolar) substrate binding to the OM long-chain fatty acid transporter FadL from Escherichia coli causes conformational changes in the N terminus that open up a channel for substrate diffusion. The OM long-chain fatty acid transporter FadL from E. coli is a unique paradigm for OM diffusion-driven transport, in which ligand gating within a {beta}-barrel membrane protein is a prerequisite for channel formation.

B Lepore; M Indic; H Pham; E Hearn; D Patel; B van den Berg

2011-12-31T23:59:59.000Z

407

Nanofiltration of Electrolyte Solutions by Sub-2nm Carbon Nanotube Membranes  

SciTech Connect (OSTI)

Both MD simulations and experimental studies have shown that liquid and gas flow through carbon nanotubes with nanometer size diameter is exceptionally fast. For applications in separation technology, selectivity is required together with fast flow. In this work, we use pressure-driven filtration experiments to study ion exclusion in silicon nitride/sub-2-nm CNT composite membranes as a function of solution ionic strength, pH, and ion valence. We show that carbon nanotube membranes exhibit significant ion exclusion at low salt concentration. Our results support a rejection mechanism dominated by electrostatic interactions between fixed membrane charges and mobile ions, while steric and hydrodynamic effects appear to be less important. Comparison with commercial nanofiltration membranes for water softening reveals that our carbon nanotube membranes provides far superior water fluxes for similar ion rejection capabilities.

Fornasiero, F; Park, H G; Holt, J K; Stadermann, M; Kim, S; In, J B; Grigoropoulos, C P; Noy, A; Bakajin, O

2008-03-13T23:59:59.000Z

408

Ion source  

DOE Patents [OSTI]

A magnetic filter for an ion source reduces the production of undesired ion species and improves the ion beam quality. High-energy ionizing electrons are confined by the magnetic filter to an ion source region, where the high-energy electrons ionize gas molecules. One embodiment of the magnetic filter uses permanent magnets oriented to establish a magnetic field transverse to the direction of travel of ions from the ion source region to the ion extraction region. In another embodiment, low energy 16 eV electrons are injected into the ion source to dissociate gas molecules and undesired ion species into desired ion species.

Leung, Ka-Ngo (Hercules, CA); Ehlers, Kenneth W. (Alamo, CA)

1984-01-01T23:59:59.000Z

409

Nanoporous Polytetrafluoroethylene/Silica Composite Separator as a High-Performance All-Vanadium Redox Flow Battery Membrane  

SciTech Connect (OSTI)

Driven by the motivation of searching for low-cost membrane alternatives, a novel nanoporous polytetrafluoroethylene/silica composite separator has been prepared and evaluated for its use in all-vanadium mixed-acid redox flow battery. This separator consisting of silica particles enmeshed in a polytetrafluoroethylene fibril matrix has no ion exchange capacity and is featured with unique nanoporous structures, which function as the ion transport channels in redox flow battery operation, with an average pore size of 38nm and a porosity of 48%. This separator has produced excellent electrochemical performance in the all-vanadium mixed-acid system with energy efficiency delivery comparable to Nafion membrane and superior rate capability and temperature tolerance. The separator also demonstrates an exceptional capacity retention capability over extended cycling, offering additional operational latitude towards conveniently mitigating the capacity decay that is inevitable for Nafion. Because of the inexpensive raw materials and simple preparation protocol, the separator is particularly low-cost, estimated to be at least an order of magnitude more inexpensive than Nafion. Plus the proven chemical stability due to the same backbone material as Nafion, this separator possesses a good combination of critical membrane requirements and shows great potential to promote market penetration of the all-vanadium redox flow battery by enabling significant reduction of capital and cycle costs.

Wei, Xiaoliang; Nie, Zimin; Luo, Qingtao; Li, Bin; Chen, Baowei; Simmons, Kevin L.; Sprenkle, Vincent L.; Wang, Wei

2013-09-02T23:59:59.000Z

410

A method of cobalt ion concentration from dilute aqueous solutions  

SciTech Connect (OSTI)

The liquid membrane technique is very useful for metal ions recovery from dilute solutions. Co{sup 2+} ions can be removed and concentrated from wastewaters with an emulsion liquid membrane. The paper describes the permeation of Co{sup 2+} using naphthenic acids as the carrier and kerosene as the membrane material. The inner phase is a HCl 3.162 x 10{sup -4} solution. The extraction yield is more than 96%.

Amanatidou, E. [Technological Education Inst., Kila Kozanis (Greece); Stefanut, M.N.; Grozav, A. [Institute for Chemical and Technological Sciences, Timisoara (Romania)

1996-03-01T23:59:59.000Z

411

Rejection and fate of trace organic compounds (TrOCs) during membrane distillation  

E-Print Network [OSTI]

Rejection and fate of trace organic compounds (TrOCs) during membrane distillation Kaushalya COCs) Direct contact membrane distillation (DCMD) Volatility Fate and transport Hydrophobicity/hydrophilicity a b s t r a c t In this study, we examined the feasibility of membrane distillation (MD) for removing

412

Alkaline membrane fuel cells with in-situ cross-linked ionomers Yongjun Leng a  

E-Print Network [OSTI]

optimization is needed for the commercialization of alkaline membrane fuel cell (AMFC) technologiesAlkaline membrane fuel cells with in-situ cross-linked ionomers Yongjun Leng a , Lizhu Wang b membrane fuel cell (AMFC) in-situ cross-linking ionomer net water transport coefficient A B S T R A C

413

Journal of Membrane Science 279 (2006) 608614 Direct measurement of nanofluxes and structural relaxations of  

E-Print Network [OSTI]

of the membrane are very important in explain- ing solvent swelling [8,9]. Besides water transport, the gas. For insufficiently hydrated Nafion® membranes, the proton transport is slow, and thus, the conversion efficiency. Originally, it was argued that the gas mainly permeates either through the hydrated ionic cluster region [10

414

Treatment of model inland brackish groundwater reverse osmosis concentrate with electrodialysis Part II: Sensitivity to voltage application and membranes  

Science Journals Connector (OSTI)

Abstract The objective of this research was to investigate the sensitivity of electrodialysis performance to variations in voltage application and membranes when treating brackish water reverse osmosis concentrate waste. Synthetic BWRO concentrates from Arizona and Texas of 789014,800mg/L total dissolved solids were prepared with poly-phosphonate antiscalants. Experimentation was performed using a laboratory-scale electrodialyzer with two sets of membranes (AMV-CMV and PCSA-PCSK) with a nominal transfer area of 64cm2 per membrane. Flow, pressure, conductivity, temperature, and pH were measured continuously, and periodic samples were analyzed for specific anion and cation concentrations. The BWRO concentrates were successfully treated with stack voltage applications of 0.51.5V/cell-pair for salinity removal ratios up to 99% with current density less than 500A/m2. This paper highlights that (1) the specific energy consumption was proportional to the applied voltage and equivalent concentration separated (i.e., approximately 0.03kWh/m3 per Volt/cell-pair applied per meq/L separated); (2) lower voltage applications decreased the relative separation rate of sulfate compared to chloride; and (3) water transport by electro-osmosis was independent of voltage application or resulting current densities, while it is affected by the ion exchange membranes.

W. Shane Walker; Younggy Kim; Desmond F. Lawler

2014-01-01T23:59:59.000Z

415

NOVEL COMPOSITE MEMBRANES FOR HYDROGEN SEPARATION IN GASIFICATION PROCESSES IN VISION 21 ENERGY PLANTS  

SciTech Connect (OSTI)

ITN Energy Systems, along with its team members, the Idaho National Engineering and Environmental Laboratory, Nexant Consulting, Argonne National Laboratory and Praxair, propose to develop a novel composite membrane structure for hydrogen separation as a key technology module within the future ''Vision 21'' fossil fuel plants. The ITN team is taking a novel approach to hydrogen separation membrane technology where fundamental engineering material development is fully integrated into fabrication designs; combining functionally graded materials, monolithic module concept and plasma spray manufacturing techniques. The technology is based on the use of Ion Conducting Ceramic Membranes (ICCM) for the selective transport of hydrogen. The membranes are comprised of composites consisting of a proton conducting ceramic and a second metallic phase to promote electrical conductivity. Functional grading of the membrane components allows the fabrication of individual membrane layers of different materials, microstructures and functions directly into a monolithic module. Plasma spray techniques, common in industrial manufacturing, are well suited for fabricating ICCM hydrogen separation modules inexpensively, yielding compact membrane modules that are amenable to large scale, continuous manufacturing with low costs. This program will develop and evaluate composite membranes and catalysts for hydrogen separation. Components of the monolithic modules will be fabricated by plasma spray processing. The engineering and economic characteristics of the proposed ICCM approach, including system integration issues, will also be assessed. This will result in a complete evaluation of the technical and economic feasibility of ICCM hydrogen separation for implementation within the ''Vision 21'' fossil fuel plant. The ICCM hydrogen separation technology is targeted for use within the gasification module of the ''Vision 21'' fossil fuel plant. The high performance and low-cost manufacturing of the proposed technology will benefit the deployment of ''Vision 21'' fossil fuel plant processes by improving the energy efficiency, flexibility and environmental performance of these plants. Of particular importance is that this technology will also produce a stream of pure carbon dioxide. This allows facile sequestration or other use of this greenhouse gas. These features will benefit the U.S. in allowing for the continued use of domestic fossil fuels in a more energy efficient and environmentally acceptable manner.

Michael Schwartz

2003-10-01T23:59:59.000Z

416

NOVEL COMPOSITE MEMBRANES FOR HYDROGEN SEPARATION IN GASIFICATION PROCESSES IN VISION 21 ENERGY PLANTS  

SciTech Connect (OSTI)

ITN Energy Systems, along with its team members, the Idaho National Engineering and Environmental Laboratory, Nexant Consulting, Argonne National Laboratory and Praxair, propose to develop a novel composite membrane structure for hydrogen separation as a key technology module within the future ''Vision 21'' fossil fuel plants. The ITN team is taking a novel approach to hydrogen separation membrane technology where fundamental engineering material development is fully integrated into fabrication designs; combining functionally graded materials, monolithic module concept and plasma spray manufacturing techniques. The technology is based on the use of Ion Conducting Ceramic Membranes (ICCM) for the selective transport of hydrogen. The membranes are comprised of composites consisting of a proton conducting ceramic and a second metallic phase to promote electrical conductivity. Functional grading of the membrane components allows the fabrication of individual membrane layers of different materials, microstructures and functions directly into a monolithic module. Plasma spray techniques, common in industrial manufacturing, are well suited for fabricating ICCM hydrogen separation modules inexpensively, yielding compact membrane modules that are amenable to large scale, continuous manufacturing with low costs. This program will develop and evaluate composite membranes and catalysts for hydrogen separation. Components of the monolithic modules will be fabricated by plasma spray processing. The engineering and economic characteristics of the proposed ICCM approach, including system integration issues, will also be assessed. This will result in a complete evaluation of the technical and economic feasibility of ICCM hydrogen separation for implementation within the ''Vision 21'' fossil fuel plant. The ICCM hydrogen separation technology is targeted for use within the gasification module of the ''Vision 21'' fossil fuel plant. The high performance and low-cost manufacturing of the proposed technology will benefit the deployment of ''Vision 21'' fossil fuel plant processes by improving the energy efficiency, flexibility and environmental performance of these plants. Of particular importance is that this technology will also produce a stream of pure carbon dioxide. This allows facile sequestration or other use of this greenhouse gas. These features will benefit the U.S. in allowing for the continued use of domestic fossil fuels in a more energy efficient and environmentally acceptable manner.

Michael Schwartz

2003-07-01T23:59:59.000Z

417

NOVEL COMPOSITE MEMBRANES FOR HYDROGEN SEPARATION IN GASIFICATION PROCESSES IN VISION 21 ENERGY PLANTS  

SciTech Connect (OSTI)

ITN Energy Systems, along with its team members, the Idaho National Engineering and Environmental Laboratory, Nexant Consulting, Argonne National Laboratory and Praxair, propose to develop a novel composite membrane structure for hydrogen separation as a key technology module within the future ''Vision 21'' fossil fuel plants. The ITN team is taking a novel approach to hydrogen separation membrane technology where fundamental engineering material development is fully integrated into fabrication designs; combining functionally graded materials, monolithic module concept and plasma spray manufacturing techniques. The technology is based on the use of Ion Conducting Ceramic Membranes (ICCM) for the selective transport of hydrogen. The membranes are comprised of composites consisting of a proton conducting ceramic and a second metallic phase to promote electrical conductivity. Functional grading of the membrane components allows the fabrication of individual membrane layers of different materials, microstructures and functions directly into a monolithic module. Plasma spray techniques, common in industrial manufacturing, are well suited for fabricating ICCM hydrogen separation modules inexpensively, yielding compact membrane modules that are amenable to large scale, continuous manufacturing with low costs. This program will develop and evaluate composite membranes and catalysts for hydrogen separation. Components of the monolithic modules will be fabricated by plasma spray processing. The engineering and economic characteristics of the proposed ICCM approach, including system integration issues, will also be assessed. This will result in a complete evaluation of the technical and economic feasibility of ICCM hydrogen separation for implementation within the ''Vision 21'' fossil fuel plant. The ICCM hydrogen separation technology is targeted for use within the gasification module of the ''Vision 21'' fossil fuel plant. The high performance and low-cost manufacturing of the proposed technology will benefit the deployment of ''Vision 21'' fossil fuel plant processes by improving the energy efficiency, flexibility and environmental performance of these plants. Of particular importance is that this technology will also produce a stream of pure carbon dioxide. This allows facile sequestration or other use of this greenhouse gas. These features will benefit the U.S. in allowing for the continued use of domestic fossil fuels in a more energy efficient and environmentally acceptable manner.

Michael Schwartz

2004-01-01T23:59:59.000Z

418

Self-Assembly and Transport Limitations in Confined Nafion Films  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Assembly and Transport Limitations in Confined Nafion Films Assembly and Transport Limitations in Confined Nafion Films Title Self-Assembly and Transport Limitations in Confined Nafion Films Publication Type Journal Article Year of Publication 2013 Authors Modestino, Miguel A., Devproshad K. Paul, Shudipto Dishari, Stephanie A. Petrina, Frances I. Allen, Michael A. Hickner, Kunal Karan, Rachel Segalman, and Adam Z. Weber Journal Macromolecules Volume 46 Issue 3 Pagination 867 - 873 Date Published 02/2013 ISSN 0024-9297 Abstract Ion-conducting polymers are important materials for a variety of electrochemical applications. Perfluorinated ionomers, such as Nafion, are the benchmark materials for proton conduction and are widely used in fuel cells and other electrochemical devices including solar-fuel generators, chlor-alkali cells, and redox flow batteries. While the behavior of Nafion in bulk membranes (10 to 100s ?m thick) has been studied extensively, understanding its properties under thin-film confinement is limited. Elucidating the behavior of thin Nafion films is particularly important for the optimization of fuel-cell catalyst layers or vapor-operated solar-fuel generators, where a thin film of ionomer is responsible for the transport of ions to and from the active electrocatalytic centers. Using a combination of transport-property measurements and structural characterization, this work demonstrates that confinement of Nafion in thin films induced thickness-dependent proton conductivity and ionic-domain structure. Confining Nafion films to thicknesses below 50 nm on a silicon substrate results in a loss of microphase separation of the hydrophilic and hydrophobic domains, which drastically increases the material?s water uptake while in turn decreasing its ionic conductivity.

419

Transport properties of discontinuous Co{sub 80}Fe{sub 20}/Al{sub 2}O{sub 3} multilayers, prepared by ion beam sputtering  

SciTech Connect (OSTI)

Ion beam sputtered Co{sub 80}Fe{sub 20}(t)/Al{sub 2}O{sub 3}(30 {angstrom}) multilayers were obtained. The Co{sub 80}Fe{sub 20} layers become discontinuous for nominal thicknesses T {le} 18{angstrom}. Tunnel magnetoresistance was measured in CIP and CPP geometries, reaching up to 6.5% at room temperature and 11% at 15 K, for as-deposited films in CIP geometry. The temperature dependence of MR was found quite different for the two geometries: fairly strong in the CIP case and almost absent in the CPP geometry. A model is proposed to explain these large differences in behavior.

Kakazei, G.N.; Freitas, P.P.; Cardoso, S.; Lopes, A.M.L.; Pereira de Azevedo, M.M.; Pogorelov, Y.G.; Sousa, J.B.

1999-09-01T23:59:59.000Z

420

Ion pump activity generates fluctuating electrostatic forces in biomembranes  

E-Print Network [OSTI]

We study the non-equilibrium dynamics of lipid membranes with proteins that actively pump ions across the membrane. We find that the activity leads to a fluctuating force distribution due to electrostatic interactions arising from variation in dielectric constant across the membrane. By applying a multipole expansion we find effects on both the tension and bending rigidity dominated parts of the membranes fluctuation spectrum. We discuss how our model compares with previous studies of force-multipole models.

B. Loubet; M. A. Lomholt

2011-09-19T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Composite zeolite membranes  

DOE Patents [OSTI]

A new class of composite zeolite membranes and synthesis techniques therefor has been invented. These membranes are essentially defect-free, and exhibit large levels of transmembrane flux and of chemical and isotopic selectivity.

Nenoff, Tina M. (Albuquerque, NM); Thoma, Steven G. (Albuquerque, NM); Ashley, Carol S. (Albuquerque, NM); Reed, Scott T. (Albuquerque, NM)

2002-01-01T23:59:59.000Z

422

Membrane Technology Workshop  

Broader source: Energy.gov [DOE]

At the Membrane Technology Workshop (held July 24, 2012, in Rosemont, IL), stakeholders from industry and academia explored the status of membrane research and development (R&D). Participants...

423

Membrane Technology Workshop  

Broader source: Energy.gov [DOE]

At the Membrane Technology Workshop (held July 24, 2012, in Rosemont, IL), stakeholders from industry and academia explored the status of membrane research and development (R&D). Participants ...

424

Hybrid adsorptive membrane reactor  

DOE Patents [OSTI]

A hybrid adsorbent-membrane reactor in which the chemical reaction, membrane separation, and product adsorption are coupled. Also disclosed are a dual-reactor apparatus and a process using the reactor or the apparatus.

Tsotsis, Theodore T. (Huntington Beach, CA); Sahimi, Muhammad (Altadena, CA); Fayyaz-Najafi, Babak (Richmond, CA); Harale, Aadesh (Los Angeles, CA); Park, Byoung-Gi (Yeosu, KR); Liu, Paul K. T. (Lafayette Hill, PA)

2011-03-01T23:59:59.000Z

425

Supertubes and Superconducting Membranes  

SciTech Connect (OSTI)

We show the equivalence between configurations that arise from string theory of type IIA, called supertubes, and superconducting membranes at the bosonic level. We find equilibrium and oscillating configurations for a tubular membrane carrying a current along its axis.

Cordero, Ruben; Miguel-Pilar, Zelin [Departamento de Fisica, Escuela Superior de Fisica y Matematicas del IPN, Edificio 9, Unidad Profesional 'Adolfo Lopez Mateos', Zacatenco, 07738 Mexico D.F. (Mexico)

2007-02-09T23:59:59.000Z

426

Membrane Separations Research  

E-Print Network [OSTI]

MEMBRANE SEPARATIONS RESEARCH James R. Fair Chemical Engineering Department The University of Texas at Austin Austin, TX 78712 ABSTRACT The use of membranes for separating gaseous and liquid mixtures has grown dramatically in the past 15... years. Applications have been dominated by light gas separations and water purification. During this pioneering period, equipment containing the membrane suIfaces has been developed to a point where failures are minimal and the membranes themselves...

Fair, J. R.

427

Membrane Technology Workshop  

Broader source: Energy.gov [DOE]

Presentation by Charles Page (Air Products & Chemicals, Inc.) for the Membrane Technology Workshop held July 24, 2012

428

Argonne Transportation Current News  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

8 Transportation News & Highlights 8 Transportation News & Highlights EDTA Publications Now Online December 2008 -- View them here. Argonne to advise battery alliance December 2008 -- A coalition of more than fourteen companies has announced the creation of a new business alliance aimed at promoting U.S. production of lithium ion batteries. The newly formed National Alliance for Advanced Transportation Battery Cell Manufacture is based in Chicago. Argonne National Laboratory will serve in an advisory role as the Alliance begins operations. More... French Auto Industry Visits Center for Transportation Research November 18, 2008 -- Representatives of the French auto industry visited the Argonne Center for Transportation Research on November 18, 2008. The purpose of the visit was to share information and discuss technology opportunities for hybrid and electric vehicles. More...

429

Polyphosphazene semipermeable membranes  

DOE Patents [OSTI]

A semipermeable, inorganic membrane is disclosed; the membrane is prepared from a phosphazene polymer and, by the selective substitution of the constituent groups bound to the phosphorous in the polymer structure, the selective passage of fluid from a feedstream can be controlled. Resistance to high temperatures and harsh chemical environments is observed in the use of the phosphazene polymers as semipermeable membranes.

Allen, Charles A. (Idaho Falls, ID); McCaffrey, Robert R. (Idaho Falls, ID); Cummings, Daniel G. (Idaho Falls, ID); Grey, Alan E. (Idaho Falls, ID); Jessup, Janine S. (Darlington, ID); McAtee, Richard E. (Idaho Falls, ID)

1988-01-01T23:59:59.000Z

430

Oxygen ion conducting materials  

DOE Patents [OSTI]

An oxygen ion conducting ceramic oxide that has applications in industry including fuel cells, oxygen pumps, oxygen sensors, and separation membranes. The material is based on the idea that substituting a dopant into the host perovskite lattice of (La,Sr)MnO.sub.3 that prefers a coordination number lower than 6 will induce oxygen ion vacancies to form in the lattice. Because the oxygen ion conductivity of (La,Sr)MnO.sub.3 is low over a very large temperature range, the material exhibits a high overpotential when used. The inclusion of oxygen vacancies into the lattice by doping the material has been found to maintain the desirable properties of (La,Sr)MnO.sub.3, while significantly decreasing the experimentally observed overpotential.

Vaughey, John (Elmhurst, IL); Krumpelt, Michael (Naperville, IL); Wang, Xiaoping (Downers Grove, IL); Carter, J. David (Bolingbrook, IL)

2003-01-01T23:59:59.000Z

431

Identification and characterization of a bacterial hydrosulphide ion channel  

SciTech Connect (OSTI)

The hydrosulphide ion (HS{sup -}) and its undissociated form, hydrogen sulphide (H{sub 2}S), which are believed to have been critical to the origin of life on Earth, remain important in physiology and cellular signalling. As a major metabolite in anaerobic bacterial growth, hydrogen sulphide is a product of both assimilatory and dissimilatory sulphate reduction. These pathways can reduce various oxidized sulphur compounds including sulphate, sulphite and thiosulphate. The dissimilatory sulphate reduction pathway uses this molecule as the terminal electron acceptor for anaerobic respiration, in which process it produces excess amounts of H{sub 2}S. The reduction of sulphite is a key intermediate step in all sulphate reduction pathways. In Clostridium and Salmonella, an inducible sulphite reductase is directly linked to the regeneration of NAD{sup +}, which has been suggested to have a role in energy production and growth, as well as in the detoxification of sulphite. Above a certain concentration threshold, both H{sub 2}S and HS{sup -} inhibit cell growth by binding the metal centres of enzymes and cytochrome oxidase, necessitating a release mechanism for the export of this toxic metabolite from the cell. Here we report the identification of a hydrosulphide ion channel in the pathogen Clostridium difficile through a combination of genetic, biochemical and functional approaches. The HS{sup -} channel is a member of the formate/nitrite transport family, in which about 50 hydrosulphide ion channels form a third subfamily alongside those for formate (FocA) and for nitrite (NirC). The hydrosulphide ion channel is permeable to formate and nitrite as well as to HS{sup -} ions. Such polyspecificity can be explained by the conserved ion selectivity filter observed in the channel's crystal structure. The channel has a low open probability and is tightly regulated, to avoid decoupling of the membrane proton gradient.

Czyzewski, Bryan K.; Wang, Da-Neng (NYUSM)

2012-10-26T23:59:59.000Z

432

Enhanced membrane gas separations  

SciTech Connect (OSTI)

An improved membrane gas separation process is described comprising: (a) passing a feed gas stream to the non-permeate side of a membrane system adapted for the passage of purge gas on the permeate side thereof, and for the passage of the feed gas stream in a counter current flow pattern relative to the flow of purge gas on the permeate side thereof, said membrane system being capable of selectively permeating a fast permeating component from said feed gas, at a feed gas pressure at or above atmospheric pressure; (b) passing purge gas to the permeate side of the membrane system in counter current flow to the flow of said feed gas stream in order to facilitate carrying away of said fast permeating component from the surface of the membrane and maintaining the driving force for removal of the fast permeating component through the membrane from the feed gas stream, said permeate side of the membrane being maintained at a subatmospheric pressure within the range of from about 0.1 to about 5 psia by vacuum pump means; (c) recovering a product gas stream from the non-permeate side of the membrane; and (d) discharging purge gas and the fast permeating component that has permeated the membrane from the permeate side of the membrane, whereby the vacuum conditions maintained on the permeate side of the membrane by said vacuum pump means enhance the efficiency of the gas separation operation, thereby reducing the overall energy requirements thereof.

Prasad, R.

1993-07-13T23:59:59.000Z

433

Fuel Cell Technologies Office: High Temperature Membrane Working Group  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

High Temperature Membrane Working Group High Temperature Membrane Working Group The High Temperature Membrane Working Group consists of government, industry, and university researchers interested in developing high temperature membranes for fuel cells. Description Technical Targets Meetings Contacts Description Polymer electrolyte membrane (PEM) fuel cells typically operate at temperatures no higher than 60°C-80°C due to structural limitations of the membrane. Operating PEM fuel cell stacks at higher temperatures (120°C for transportation and 150°C for stationary applications), however, would yield significant energy benefits. For example, heat rejection is easier at higher temperatures, which would allow use of smaller heat exchangers in fuel cell power systems. In addition, for reformate fuel cell systems, carbon monoxide (CO) tolerance of the stack is less problematic at higher temperatures, which would reduce the size requirements or possibly eliminate the need for some CO clean-up beds in the fuel processor.

434

Argonne CNM News: Thinnest Nanofiltration Membrane to Date  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Thinnest Nanofiltration Membrane to Date Thinnest Nanofiltration Membrane to Date Thinnest membrane to date Close-packed nanoparticle monolayers self-assembled from dodecanethiol-ligated gold nanocrystals. TEM image (left) and atomistic simulation of tryptophan transport through a pore. A recent collaboration between users at the University of Chicago and the University of Illinois at Chicago with the Center for Nanoscale Material's Electronic & Magnetic Materials & Devices Group has produced the thinnest nanofiltration membrane achieved thus far, at ~30 nm, made of just four layers of nanoparticles. A separation membrane is a key component in both nanofiltration and reverse osmosis filtration systems. Typically they are microns-thick polymer films. Reducing the thickness of the membrane reduces the pressure that needs to

435

E-Print Network 3.0 - aluminium ions Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Otty, Mass and heat transfer in ion-exchange membranes (1996) 7. Belinda Flem, Peltier... heats in cryolite melts with alumina (1996) 8. Ellen Marie Hansen, Modelling of...

436

Net-baryon-, net-proton-, and net-charge kurtosis in heavy-ion collisions within a relativistic transport approach  

E-Print Network [OSTI]

We explore the potential of net-baryon, net-proton and net-charge kurtosis measurements to investigate the properties of hot and dense matter created in relativistic heavy-ion collisions. Contrary to calculations in a grand canonical ensemble we explicitly take into account exact electric and baryon charge conservation on an event-by-event basis. This drastically limits the width of baryon fluctuations. A simple model to account for this is to assume a grand-canonical distribution with a sharp cut-off at the tails. We present baseline predictions of the energy dependence of the net-baryon, net-proton and net-charge kurtosis for central ($b\\leq 2.75$ fm) Pb+Pb/Au+Au collisions from $E_{lab}=2A$ GeV to $\\sqrt{s_{NN}}=200$ GeV from the UrQMD model. While the net-charge kurtosis is compatible with values around zero, the net-baryon number decreases to large negative values with decreasing beam energy. The net-proton kurtosis becomes only slightly negative for low $\\sqrt{s_{NN}}$.

Marlene Nahrgang; Tim Schuster; Michael Mitrovski; Reinhard Stock; Marcus Bleicher

2012-09-03T23:59:59.000Z

437

Glucose Transporters in the Transepithelial Transport of Glucose  

Science Journals Connector (OSTI)

......galactose, and fructose formed by the hydrolysis of dietary car- bohydrates.181 In the liver, GLUT2 at the sinusoidal membrane...transport activity. These results show that SGLTl is a key defective molecule in GGM and that SGLTl is crucial for the absorption......

Kuniaki Takata

1996-08-01T23:59:59.000Z

438

Novel Composite Membranes for Hydrogen Separation in Gasification Processes in Vision 21 Energy Plants  

SciTech Connect (OSTI)

ITN Energy Systems, Inc. (ITN) and its partners, the Idaho National Engineering and Environmental Laboratory, Argonne National Laboratory, Nexant Consulting, LLC and Praxair, Inc. are developing composite membranes for hydrogen separation as a key technology module within the future ''Vision 21'' fossil fuel plants. The ITN team is pursuing a novel approach to hydrogen separation membrane technology where fundamental engineering material development is fully integrated into module fabrication designs; combining functionally-graded materials, monolithic module concept and thermal spray manufacturing techniques. The technology is based on the use of Ion Conducting Ceramic Membranes (ICCM) for the selective transport of hydrogen. The membranes are comprised of composites consisting of a proton conducting ceramic and a second metallic phase to promote electrical conductivity. Functional grading of the membrane components allows for the fabrication of individual membrane layers of different materials, microstructures and functions directly into a monolithic module. Plasma spray techniques, common in industrial manufacturing, are well suited for fabricating ICCM hydrogen separation modules inexpensively, yielding compact membrane modules that are amenable to large scale, continuous manufacturing techniques with low costs. The engineering and economic characteristics of the proposed ICCM approach, including system integration issues, are being assessed. This will result in an evaluation of the technical and economic feasibility of the proposed ICCM hydrogen separation approach for implementation within the ''Vision 21'' fossil fuel plant. The ICCM hydrogen separation technology is targeted for use within the gasification module of the ''Vision 21'' fossil fuel plant. The high performance and low-cost manufacturing of the proposed technology will benefit the deployment of ''Vision 21'' fossil fuel plant processes by improving the energy efficiency, flexibility and environmental performance of such plants. Of particular importance is that the proposed technology also results in a stream of pure carbon dioxide. This allows for the facile sequestration or other use of this greenhouse gas. These features will benefit the U.S. in allowing for the continued use of domestic fossil fuels in a more energy efficient and environmentally acceptable manner.

Schwartz, Michael

2001-11-06T23:59:59.000Z

439

EXTRACTION COMPRESSION AND ACCELERATION OF HIGH LINE CHARGE DENSITY ION BEAMS  

E-Print Network [OSTI]

on compression of heavy ion beams for creating high energyet al, Highly Compressed Ion Beams for High Energy DensityPulsed Solenoid for Intense Ion Beam Transport, these Proc:

Henestroza, E.

2008-01-01T23:59:59.000Z

440

Substituted polyacetylene separation membrane  

DOE Patents [OSTI]

A separation membrane is described which is useful for gas separation, particularly separation of C{sub 2+} hydrocarbons from natural gas. The invention encompasses the membrane itself, methods of making it and processes for using it. The membrane comprises a polymer having repeating units of a hydrocarbon-based, disubstituted polyacetylene, having the general formula shown in the accompanying diagram, wherein R{sub 1} is chosen from the group consisting of C{sub 1}-C{sub 4} alkyl and phenyl, and wherein R{sub 2} is chosen from the group consisting of hydrogen and phenyl. In the most preferred embodiment, the membrane comprises poly(4-methyl-2-pentyne) [PMP]. The membrane exhibits good chemical resistance and has super-glassy properties with regard to separating certain large, condensable permeant species from smaller, less-condensable permeant species. The membranes may also be useful in other fluid separations. 4 figs.

Pinnau, I.; Morisato, Atsushi

1998-01-13T23:59:59.000Z

Note: This page contains sample records for the topic "ion transport membrane" from the National Library of EnergyBeta (NLEBeta).
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441

Substituted polyacetylene separation membrane  

DOE Patents [OSTI]

A separation membrane useful for gas separation, particularly separation of C.sub.2+ hydrocarbons from natural gas. The invention encompasses the membrane itself, methods of making it and processes for using it. The membrane comprises a polymer having repeating units of a hydrocarbon-based, disubstituted polyacetylene, having the general formula: ##STR1## wherein R.sub.1 is chosen from the group consisting of C.sub.1 -C.sub.4 alkyl and phenyl, and wherein R.sub.2 is chosen from the group consisting of hydrogen and phenyl. In the most preferred embodiment, the membrane comprises poly(4-methyl-2-pentyne) PMP!. The membrane exhibits good chemical resistance and has super-glassy properties with regard to separating certain large, condensable permeant species from smaller, less-condensable permeant species. The membranes may also be useful in other fluid separations.

Pinnau, Ingo (Palo Alto, CA); Morisato, Atsushi (Tokyo, JP)

1998-01-13T23:59:59.000Z

442

EVALUATION OF PROTON-CONDUCTING MEMBRANES FOR USE IN A SULFUR-DIOXIDE DEPOLARIZED ELECTROLYZER  

SciTech Connect (OSTI)

The chemical stability, sulfur dioxide transport, ionic conductivity, and electrolyzer performance have been measured for several commercially available and experimental proton exchange membranes (PEMs) for use in a sulfur dioxide depolarized electrolyzer (SDE). The SDE's function is to produce hydrogen by using the Hybrid Sulfur (HyS) Process, a sulfur based electrochemical/thermochemical hybrid cycle. Membrane stability was evaluated using a screening process where each candidate PEM was heated at 80 C in 60 wt. % H{sub 2}SO{sub 4} for 24 hours. Following acid exposure, chemical stability for each membrane was evaluated by FTIR using the ATR sampling technique. Membrane SO{sub 2} transport was evaluated using a two-chamber permeation cell. SO{sub 2} was introduced into one chamber whereupon SO{sub 2} transported across the membrane into the other chamber and oxidized to H{sub 2}SO{sub 4} at an anode positioned immediately adjacent to the membrane. The resulting current was used to determine the SO{sub 2} flux and SO{sub 2} transport. Additionally, membrane electrode assemblies (MEAs) were prepared from candidate membranes to evaluate ionic conductivity and selectivity (ionic conductivity vs. SO{sub 2} transport) which can serve as a tool for selecting membranes. MEAs were also performance tested in a HyS electrolyzer measuring current density versus a constant cell voltage (1V, 80 C in SO{sub 2} saturated 30 wt% H2SO{sub 4}). Finally, candidate membranes were evaluated considering all measured parameters including SO{sub 2} flux, SO{sub 2} transport, ionic conductivity, HyS electrolyzer performance, and membrane stability. Candidate membranes included both PFSA and non-PFSA polymers and polymer blends of which the non-PFSA polymers, BPVE-6F and PBI, showed the best selectivity.

Hobbs, D.; Elvington, M.; Colon-Mercado, H.

2009-11-11T23:59:59.000Z

443

SLAC1-related signal transduction pathway involved in ABA- induced stomatal closure and K? selective transport by the OsHKT2;4 transporter from rice (Oryza sativa) with atypical Na? transport properties and competition in permeation of K? over Mg? and Ca? ions  

E-Print Network [OSTI]

of K + over Mg 2+ and Ca 2+ ions Figure 2.1. OsHKT2;4protein kinases with distinct Ca 2+ affinities. Proc. Natl.Abscisic Acid, CO 2 , and Ca 2 + Signaling. Annu. Rev. Plant

Brodsky, Dennis E.

2011-01-01T23:59:59.000Z

444

GRAPHENE BASED ANODE MATERIALS FOR LITHIUM-ION BATTERIES.  

E-Print Network [OSTI]

??Improvements of the anode performances in Li-ions batteries are in demand to satisfy applications in transportation. In comparison with graphitic carbons, transition metal oxides as (more)

Cheekati, Sree Lakshmi

2011-01-01T23:59:59.000Z

445

Transportation Services  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

Transportation Services Transporting nuclear materials within the United States and throughout the world is a complicated and sometimes highly controversial effort requiring...

446

Local Transportation  

E-Print Network [OSTI]

Local Transportation. Transportation from the Airport to Hotel. There are two types of taxi companies that operate at the airport: special and regular taxis (

447

E-Print Network 3.0 - anion transporter sat1 Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

(ClC) family... in the complex network of membrane transport and solute fluxes. We used a reverse genetics approach with T Source: Groningen, Rijksuniversiteit - Centre for...

448

E-Print Network 3.0 - anion transporters oat1 Sample Search Results  

Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

(ClC) family... in the complex network of membrane transport and solute fluxes. We used a reverse genetics approach with T Source: Groningen, Rijksuniversiteit - Centre for...

449

Does ionophore A23187 mediate Na transport in the absence of divalent cations?  

Science Journals Connector (OSTI)

... L. & Beaug, L. in Transport Across Biological Membranes (eds Giebisch, G., Tosteson, D. C. & Ussing, H. H.) vol. 2 (Springer, in ...

PETER FLATMAN; VIRGILIO L. LEW

1977-12-01T23:59:59.000Z

450

Integrated Ceramic Membrane System for Hydrogen Production  

SciTech Connect (OSTI)

Phase I was a technoeconomic feasibility study that defined the process scheme for the integrated ceramic membrane system for hydrogen production and determined the plan for Phase II. The hydrogen production system is comprised of an oxygen transport membrane (OTM) and a hydrogen transport membrane (HTM). Two process options were evaluated: 1) Integrated OTM-HTM reactor in this configuration, the HTM was a ceramic proton conductor operating at temperatures up to 900C, and 2) Sequential OTM and HTM reactors in this configuration, the HTM was assumed to be a Pd alloy operating at less than 600C. The analysis suggested that there are no technical issues related to either system that cannot be managed. The process with the seque