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1

Structures for Three Membrane Transport Proteins Yield Functional...  

NLE Websites -- All DOE Office Websites (Extended Search)

to the guardians at old-time city gates who controlled the flux of "goods" through the city walls, specialized membrane transport proteins catalyze the flow across cell...

2

Structures for Three Membrane Transport Proteins Yield Functional Insights  

NLE Websites -- All DOE Office Websites (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.

3

How the Membrane Protein AmtB Transports Ammonia  

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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."

4

Protein Flips Lipids Across Membranes  

NLE Websites -- All DOE Office Websites (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.

5

Protein Flips Lipids Across Membranes  

NLE Websites -- All DOE Office Websites (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.

6

Protein Flips Lipids Across Membranes  

NLE Websites -- All DOE Office Websites (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.

7

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect

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

8

OXYGEN TRANSPORT CERAMIC MEMBRANES  

SciTech Connect

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

9

OXYGEN TRANSPORT CERAMIC MEMBRANES  

Science Conference Proceedings (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

10

Oxygen Transport Membranes  

Science Conference Proceedings (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 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 (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

11

Oxygen Transport Membranes  

SciTech Connect

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

12

Water Transport and Sorption in Nafion Membrane  

NLE Websites -- All DOE Office Websites (Extended Search)

Transport and Sorption in Nafion Membrane Title Water Transport and Sorption in Nafion Membrane Publication Type Book Chapter Year of Publication 2012 Authors Kusoglu, Ahmet, and...

13

Nanoengineered membranes for controlled transport  

DOE Patents (OSTI)

A nanoengineered membrane for controlling material transport (e.g., molecular transport) is disclosed. The membrane includes a substrate, a cover defining a material transport channel between the substrate and the cover, and a plurality of fibers positioned in the channel and connected to and extending away from a surface of the substrate. The fibers are aligned perpendicular to the surface of the substrate, and have a width of 100 nanometers or less. The diffusion limits for material transport are controlled by the separation of the fibers. In one embodiment, chemical derivatization of carbon fibers may be undertaken to further affect the diffusion limits or affect selective permeability or facilitated transport. For example, a coating can be applied to at least a portion of the fibers. In another embodiment, individually addressable carbon nanofibers can be integrated with the membrane to provide an electrical driving force for material transport.

Doktycz, Mitchel J. (Oak Ridge, TN); Simpson, Michael L. (Knoxville, TN); McKnight, Timothy E. (Greenback, TN); Melechko, Anatoli V. (Oak Ridge, TN); Lowndes, Douglas H. (Knoxville, TN); Guillorn, Michael A. (Knoxville, TN); Merkulov, Vladimir I. (Oak Ridge, TN)

2010-01-05T23:59:59.000Z

14

Oxygen Transport Ceramic Membranes  

Science Conference Proceedings (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

15

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

16

Oxygen Transport Ceramic Membranes  

Science Conference Proceedings (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

17

Oxygen Transport Ceramic Membranes  

Science Conference Proceedings (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

18

NETL: Gasification Systems - Advanced Hydrogen Transport Membranes...  

NLE Websites -- All DOE Office Websites (Extended Search)

Advanced Hydrogen Transport Membranes for Coal Gasification Project No.: DE-FE0004908 Membranes shown (from top to bottom): ceramic support, activated and coated with palladium...

19

Oxygen Transport Ceramic Membranes  

Science Conference Proceedings (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

20

NETL: Gasification - Advanced Hydrogen Transport Membranes for...  

NLE Websites -- All DOE Office Websites (Extended Search)

Syngas Processing Systems Advanced Hydrogen Transport Membranes for Coal Gasification Praxair Inc. Project Number: FE0004908 Project Description Praxair is conducting research to...

Note: This page contains sample records for the topic "membrane transport proteins" 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

Catalyst containing oxygen transport membrane  

Science Conference Proceedings (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

22

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

23

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

24

Anion Exchange Membranes - Transport/Conductivity  

NLE Websites -- All DOE Office Websites (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

25

Active Transport 1 MEMBRANE FUNCTION, Part 3  

E-Print Network (OSTI)

Active Transport 1 MEMBRANE FUNCTION, Part 3 Active Transport1 Active Transport: If the cell must expenditure is required when a substance is moved up (against) a concentration gradient or when concrete. A good example is the Na+ / K+ pump (also known as the Na+ / K+ ATPase). It translocates both Na

Prestwich, Ken

26

Liners for ion transport membrane systems  

SciTech Connect

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

27

Synthesizing Membrane Proteins Using In Vitro Methodology ...  

Scientists at Argonne National Laboratory have created an in vitro , cell-free system and method for producing several types of protein: membrane ...

28

Effective Potential Energy Expression for Membrane Transport  

E-Print Network (OSTI)

All living cells transport molecules and ions across membranes, often against concentration gradients. This active transport requires continual energy expenditure and is clearly a nonequilibrium process for which standard equilibrium thermodynamics is not rigorously applicable. Here we derive a nonequilibrium effective potential that evaluates the per particle transport energy invested by the membrane. A novel method is used whereby a Hamiltonian function is constructed using particle concentrations as generalized coordinates. The associated generalized momenta are simply related to the individual particle energy from which we identify the effective potential. Examples are given and the formalism is compared with the equilibrium Gibb's free energy.

Robert W. Finkel

2007-02-11T23:59:59.000Z

29

Oxy-combustion: Oxygen Transport Membrane Development  

NLE Websites -- All DOE Office Websites (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

30

A bacterial factory for the production of MEMBRANE PROTEINS  

Office of Technology Transfer A bacterial factory for the production of MEMBRANE PROTEINS Cell membranes are important biological structures as they ...

31

Development of Ion Transport Membrane (ITM) Oxygen Technology...  

NLE Websites -- All DOE Office Websites (Extended Search)

Ion Transport Membrane (ITM) Oxygen Technology for Integration in IGCC and Other Advanced Power Generation Systems Background The Gasification Technologies Program at the National...

32

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

33

Feed gas contaminant removal in ion transport membrane systems  

DOE Patents (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

34

Secondary Transport Phenomena in Ceramic Membranes under ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Dense ceramic membranes are used at high temperatures as ... Stability and Oxygen Exchange Kinetics of Oxide Hetero-Junction Electrodes.

35

NETL: Gasification - Advanced Hydrogen Transport Membranes for Coal  

NLE Websites -- All DOE Office Websites (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.

36

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

SciTech Connect

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

37

The functions of tryptophan residues in membrane proteins  

SciTech Connect

Membrane proteins in general have a significantly higher Trp content than do soluble proteins. This is especially true for the M and L subunits of the photosynthetic reaction center from purple bacteria. The Trp residues are located mostly in the segments that connect the transmembrane helices. Further, they are concentrated at the periplasmic side of the complex. Within the protein subunits, many form hydrogen bonds with carbonyl oxygens of the main chain, thereby stabilizing the protein. On the surface of the molecule, they are correctly positioned to form hydrogen bonds with the lipid head groups while their hydrophobic rings are immersed in the lipid part of the bilayer. We suggest that Trp residues are involved in the translocation of protein through the membrane and that following translocation, Trp residues serve as anchors on the periplasmic side of the membrane.

Schiffer, M.; Chang, C.H.; Stevens, F.J.

1994-08-01T23:59:59.000Z

38

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (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

39

Statistical Thermodynamics of Membrane Bending-Mediated Protein–Protein Attractions  

E-Print Network (OSTI)

ABSTRACT Highly wedge-shaped integral membrane proteins, or membrane-adsorbed proteins can induce long-ranged deformations. The strain in the surrounding bilayer creates relatively long-ranged forces that contribute to interactions with nearby proteins. In contrast, to direct short-ranged interactions such as van der Waal’s, hydrophobic, or electrostatic interactions, both local membrane Gaussian curvature and protein ellipticity can induce forces acting at distances of up to a few times their typical radii. These forces can be attractive or repulsive, depending on the proteins ’ shape, height, contact angle with the bilayer, and a pre-existing local membrane curvature. Although interaction energies are not pairwise additive, for sufficiently low protein density, thermodynamic properties depend only upon pair interactions. Here, we compute pair interaction potentials and entropic contributions to the two-dimensional osmotic pressure of a collection of noncircular proteins. For flat membranes, bending rigidities of ?100k BT, moderate ellipticities, and large contact angle proteins, we find thermally averaged attractive interactions of order k BT. These interactions may play an important role in the intermediate stages of protein aggregation. Numerous biological processes where membrane bending-mediated interactions may be relevant are cited, and possible experiments are discussed.

Tom Chou; Ken S. Kim; George Oster

2001-01-01T23:59:59.000Z

40

Differential Expression in Phanerochaete chrysosporium of Membrane-Associated Proteins Relevant to Lignin Degradation  

DOE Green Energy (OSTI)

Fungal lignin-degrading systems must include membrane-associated proteins that participate in diverse processes such as uptake and oxidation of lignin fragments, secretion of ligninolytic secondary metabolites, and defense of the mycelium against ligninolytic oxidants. Despite their importance, little is known about the nature or regulation of these membrane-associated components. We grew the white rot basidiomycete Phanerochaete chrysosporium on cellulose or glucose as the carbon source and monitored the mineralization of a 14C-labeled synthetic lignin by these cultures to assess their ligninolytic competence. The results showed that the cellulose-grown cultures were ligninolytic, whereas the glucose-grown ones were not. We isolated microsomal membrane fractions from both types of culture and analyzed tryptic digests of them by shotgun liquid chromatography/tandem mass spectrometry. Comparison of the results against the predicted P. chrysosporium proteome showed that a catalase (Joint Genome Institute P. chrysosporium protein I.D. 124398), an alcohol oxidase (126879), two transporters (137220 and 132234), and two cytochrome P450s (5011 and 8912) were up-regulated under ligninolytic conditions. Real time reverse transcription polymerase chain reaction assays showed that RNA transcripts encoding all of these proteins were also up-regulated in ligninolytic cultures. Catalase 124398, alcohol oxidase 126879, and transporter 137220 were found in a proteomic analysis of partially purified plasma membranes from ligninolytic P. chrysosporium, and are therefore most likely associated with the outer envelope of the fungus.

Shary, Semarjit; Kapich, Alexander N.; Panisko, Ellen A.; Magnuson, Jon K.; Cullen, Dan; Hammel, Ken

2008-10-02T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (OSTI)

The objective of this project is to develop an environmentally benign, inexpensive, and efficient method for separating hydrogen from gas mixtures produced during industrial processes, such as coal gasification. 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 with hydrogen permeable alloys. The primary technical challenge in achieving the goals of this project will be to optimize membrane composition to enable practical hydrogen separation rates and chemical stability. Other key aspects of this developing technology include catalysis, ceramic processing methods, and separation unit design operating under high pressure. To achieve these technical goals, Eltron Research Inc. has organized a consortium consisting of CoorsTek, Sued Chemie, Inc. (SCI), Argonne National Laboratory (ANL), and NORAM. Hydrogen permeation rates in excess of 50 mL {center_dot} min{sup -1} {center_dot} cm{sup 2} at {approx}440 C were routinely achieved under less than optimal experimental conditions using a range of membrane compositions. Factors that limit the maximum permeation attainable were determined to be mass transport resistance of H{sub 2} to and from the membrane surface, as well as surface contamination. Mass transport resistance was partially overcome by increasing the feed and sweep gas flow rates to greater than five liters per minute. Under these experimental conditions, H2 permeation rates in excess of 350 mL {center_dot} min{sup -1} {center_dot} cm{sup 2} at {approx}440 C were attained. These results are presented in this report, in addition to progress with cermets, thin film fabrication, catalyst development, and H{sub 2} separation unit scale up.

Shane E. Roark; Anthony F. Sammells; Richard Mackay; Scott R. Morrison; Sara L. Rolfe; U. Balachandran; Richard N. Kleiner; James E. Stephen; Frank E. Anderson; Shandra Ratnasamy; Jon P. Wagner; Clive Brereton

2004-01-30T23:59:59.000Z

42

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (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 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. 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. The proposed technology addresses the DOE Vision 21 initiative in two ways. First, this process offers a relatively inexpensive solution for pure hydrogen separation that can be easily incorporated into Vision 21 fossil fuel plants. Second, this process could reduce the cost of hydrogen, which is a clean burning fuel under increasing demand as supporting technologies are developed for hydrogen utilization and storage. Additional motivation for this project arises from the potential of this technology for other applications. Membranes testing during this reporting period were greater than 1 mm thick and had the general perovskite composition AB{sub 1-x}B'{sub x}O{sub 3-{delta}}, where 0.05 {<=} x {<=} 0.3. These materials demonstrated hydrogen separation rates between 1 and 2 mL/min/cm{sup 2}, which represents roughly 20% of the target goal for membranes of this thickness. The sintered membranes were greater than 95% dense, but the phase purity decreased with increasing dopant concentration. The quantity of dopant incorporated into the perovskite phase was roughly constant, with excess dopant forming an additional phase. Composite materials with distinct ceramic and metallic phases, and thin film perovskites (100 {micro}m) also were successfully prepared, but have not yet been tested for hydrogen transport. Finally, porous platinum was identified as a excellent catalyst for evaluation of membrane materials, however, lower cost nickel catalyst systems are being developed.

Shane E. Roark; Tony F. Sammells; Adam Calihman; Andy Girard; Pamela M. Van Calcar; Richard Mackay; Tom Barton; Sara Rolfe

2001-01-30T23:59:59.000Z

43

Amyloid precursor protein and axonal transport  

E-Print Network (OSTI)

relationship to axonal transport . 1 Chapter II – Mutationsits axonal transport ……………………………. ………………………. ……………… 10undergoes axonal transport ……………………. 42 Figure 2.4. Effect

Rodrigues, Elizabeth M.

2010-01-01T23:59:59.000Z

44

NETL: Gasification - Development of Ion-Transport Membrane Oxygen  

NLE Websites -- All DOE Office Websites (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.

45

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

46

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

E-Print Network (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

2011-10-19T23:59:59.000Z

47

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants  

DOE Green Energy (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

48

Protein kinase and phosphatase activities of thylakoid membranes  

DOE Green Energy (OSTI)

Dephosphorylation of the 25 and 27 kDa light-harvesting Chl a/b proteins (LHCII) of the thylakoid membranes is catalyzed by a phosphatase which differs from previously reported thylakoid-bound phosphatases in having an alkaline pH optimum (9.0) and a requirement for Mg/sup 2 +/ ions. Dephosphorylation of the 8.3 kDa psb H gene product requires a Mg/sup 2 +/ ion concentration more than 200 fold higher than that for dephosphorylation of LHC II. The 8.3 kDa and 27 kDa proteins appear to be phosphorylated by two distinct kinases, which differ in substrate specificity and sensitivity to inhibitors. The plastoquinone antagonist 2,5-dibromo-3-methyl-6-isopropyl-benzoquinone (DBMIB) inhibits phosphorylation of the 27 kDa LHC II much more readily than phosphorylation of the 8.3 kDa protein. A similar pattern of inhibition is seen for two synthetic oligopeptides (MRKSATTKKAVC and ATQTLESSSRC) which are analogs of the phosphorylation sites of the two proteins. Possible modes of action of DBMIB are discussed. 45 refs., 7 figs., 3 tabs.

Michel, H.; Shaw, E.K.; Bennett, J.

1987-01-01T23:59:59.000Z

49

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (OSTI)

During this quarter, work was focused on testing layered composite membranes under varying feed stream flow rates at high pressure. By optimizing conditions, H{sub 2} permeation rates as high as 423 mL {center_dot} min{sup -1} {center_dot} cm{sup -2} at 440 C were measured. Membrane stability was investigated by comparison to composite alloy membranes. Permeation of alloyed membranes showed a strong dependence on the alloying element. Impedance analysis was used to investigate bulk and grain boundary conductivity in cermets. Thin film cermet deposition procedures were developed, hydrogen dissociation catalysts were evaluated, and hydrogen separation unit scale-up issues were addressed.

Carl R. Evenson; Anthony F. Sammells; Richard Mackay; Richard Treglio; Sara L. Rolfe; Richard Blair; U. Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; Chandra Ratnasamy; Jon P. Wagner; Clive Brereton; Warren Wolfs

2004-07-26T23:59:59.000Z

50

Towards understanding of Nipah virus attachment protein assembly and the role of protein affinity and crowding for membrane curvature events.  

SciTech Connect

Pathogenic viruses are a primary threat to our national security and to the health and economy of our world. Effective defense strategies to combat viral infection and spread require the development of understanding of the mechanisms that these pathogens use to invade the host cell. We present in this report results of our research into viral particle recognition and fusion to cell membranes and the role that protein affinity and confinement in lipid domains plays in membrane curvature in cellular fusion and fission events. Herein, we describe 1) the assembly of the G attachment protein of Nipah virus using point mutation studies to define its role in viral particle fusion to the cell membrane, 2) how lateral pressure of membrane bound proteins induce curvature in model membrane systems, and 3) the role of membrane curvature in the selective partitioning of molecular receptors and specific affinity of associated proteins.

Stachowiak, Jeanne C.; Hayden, Carl C.; Negrete, Oscar A.; Davis, Ryan Wesley; Sasaki, Darryl Yoshio

2013-10-01T23:59:59.000Z

51

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

52

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

53

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

54

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (OSTI)

During this quarter, work was focused on characterizing the stability of layered composite membranes in a one hundred percent permeate environment. Permeation data was also collected on cermets as a function of thickness. A thin film deposition procedure was used to deposit dense thin BCY/Ni onto a tubular porous support. Thin film tubes were then tested for permeation at ambient pressure. Process flow diagrams were prepared for inclusion of hydrogen separation membranes into IGCC power plants under varying conditions. Finally, membrane promoted alkane dehydrogenation experiments were performed.

Carl R. Evenson; Anthony F. Sammells; Richard T. Treglio; U. Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; Clive Brereton; Warren Wolfs; James Lockhart

2004-10-21T23:59:59.000Z

55

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (OSTI)

During this quarter long term and high pressure hydrogen separation experiments were performed on Eltron's composite layered membranes. Membranes were tested at 400 C and a 300 psig feed stream with 40% hydrogen for up to 400 continuous hours. In addition membranes were tested up to 1000 psig as demonstration of the ability for this technology to meet DOE goals. Progress was made in the development of new hydrogen separation cermets containing high permeability metals. A sulfur tolerant catalyst deposition technique was optimized and engineering work on mechanical and process & control reports was continued.

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

2005-04-30T23:59:59.000Z

56

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (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

57

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

58

Water transport in fuel cell membranes measured by laser interferometry  

E-Print Network (OSTI)

(cont.) The coefficients of electro-osmotic drag were found to increase with the increasing water content, which indicates that the Grotthuss mechanism of proton transfer is not active in the membranes with low water ...

Kim, Jungik, 1973-

2009-01-01T23:59:59.000Z

59

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (OSTI)

During this quarter catalyst stability studies were performed on Eltron's composite layered membranes. In addition, permeation experiments were performed to determine the effect of crystallographic orientation on membrane performance. Sintering conditions were optimized for preparation of new cermets containing high permeability metals. Theoretical calculations were performed to determine potential sulfur tolerant catalysts. Finally, work was continued on mechanical and process & control documentation for a hydrogen separation unit.

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

2005-07-29T23:59:59.000Z

60

Dynamic and collective analysis of membrane protein interaction network based on gene regulatory network model  

Science Conference Proceedings (OSTI)

Membrane protein interactions are vitally important for every process in a living cell. Information about these interactions can improve our understanding of diseases and provide the basis to revolutionize therapeutic treatments. However, current experimental ... Keywords: Bio-network, Dynamic and collective control, Gene regulatory network, Membrane protein interaction network, Robustness, Scale free distributing, Small-world network

Yong-Sheng Ding; Yi-Zhen Shen; Li-Hong Ren; Li-Jun Cheng

2012-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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

Solvation and Ionic Transport in Polymer Electrolyte Membranes  

DOE Green Energy (OSTI)

We developed a general theoretical framework to study the problem of proton solvation and transport in Nafion{reg_sign} and related materials.

Zawodzinski, T.A., Jr.; Paddison, S.J.; Reagor, D.; Pratt, L.R.

1999-06-03T23:59:59.000Z

62

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (OSTI)

During this quarter, work was focused on testing layered composite membranes under varying feed stream flow rates at high pressure. By optimizing conditions, H{sub 2} permeation rates in excess of 400 mL {center_dot} min{sup -1} {center_dot} cm{sup -2} at 440 C were measured. Membrane stability was characterized by repeated thermal and pressure cycling. The effect of cermet grain size on permeation was determined. Finally, progress is summarized on thin film cermet fabrication, catalyst development, and H{sub 2} separation unit scale up.

Carl R. Evenson; Anthony F. Sammells; Richard Mackay; Scott R. Morrison; Sara L. Rolfe; Richard Blair; U. Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; Chandra Ratnasamy; Jon P. Wagner; Clive Brereton; Warren Wolfs

2004-04-26T23:59:59.000Z

63

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (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. Over the past 12 months, this project has focused 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. The ceramic/ceramic composites demonstrate the lowest hydrogen permeation rates, with a maximum of approximately 0.1 mL/min/cm{sup 2} for 0.5-mm thick membranes at 800 to 950 C. Under equivalent conditions, cermets achieve a hydrogen permeation rate near 1 mL/min/cm{sup 2}, and the metal phase also improves structural stability and surface catalysis for hydrogen dissociation. Furthermore, if metals with high hydrogen permeability are used in cermets, permeation rates near 4 mL/min/cm{sup 2} are achievable with relatively thick membranes. Layered composite membranes have by far the highest permeation rates with a maximum flux in excess of 200 mL {center_dot} min{sup -1} {center_dot} cm{sup -2}. Moreover, these permeation rates were achieved at a total pressure differential across the membrane of 450 psi. Based on these results, effort during the next year will focus on this category of membranes. This report contains long-term hydrogen permeation data over eight-months of continuous operation, and permeation results as a function of operating conditions at high pressure for layered composite membranes. Additional progress with cermet and thin film membranes also is presented.

Shane E. Roark; Anthony F. Sammells; Richard Mackay; Stewart R. Schesnack; Scott R. Morrison; Thomas F. Barton; Sara L. Rolfe; U. Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; Aaron L. Wagner; Jon P. Wagner

2003-10-30T23:59:59.000Z

64

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (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

65

Radiation inactivation of membrane proteins: molecular weight estimates in situ and after Triton X-100 solubilization  

SciTech Connect

Target size analysis by radiation inactivation is widely used for molecular weight determination of membrane enzymes and receptors in situ without the need for prior solubilization or purification. However, since most molecular weight data available in the literature on membrane proteins involve the use of detergents for solubilization, the target sizes of membrane proteins in situ and after solubilization by detergent treatment have been compared. Using data from the literature and personal results, three different types of behavior of membrane proteins in presence of detergents were found: (i) uncoupling of subunits; (ii) coupling of protein molecules; and (iii) no major change in quaternary structure. For all these proteins, there is a statistically significant increase in target size of about 24% over the value obtained in situ without detergent. A relatively large body of literature data involving a variety of membrane proteins, membrane types, and irradiation conditions (electron accelerators or /sup 60/Co sources, and proteins irradiated in lyophilized form or frozen solution) was examined, and it was concluded that target sizes of membrane proteins, irradiated in the presence of Trition X-100, should be diminished by a factor of about 24% to obtain the molecular weight value.

Beauregard, G.; Potier, M.

1984-08-01T23:59:59.000Z

66

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

67

Magic angle spinning NMR applied to membrane protein 2D crystals : the structure and function of VDAC  

E-Print Network (OSTI)

Membrane proteins mediate critical functions in biological systems and are important drug targets for a number of diseases. Determining the three-dimensional structure and function of membrane proteins under physologically ...

Eddy, Matthew T. (Matthew Thomas)

2012-01-01T23:59:59.000Z

68

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants  

DOE Green Energy (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

69

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants  

DOE Green Energy (OSTI)

During this quarter composite layered membrane size was scaled-up and tested for permeation performance. Sintering conditions were optimized for a new cermet containing a high permeability metal and seals were developed to allow permeability testing. Theoretical calculations were performed to determine potential sulfur tolerant hydrogen dissociation catalysts. Finally, work was finalized on mechanical and process & control documentation for a hydrogen separation unit.

Carl R. Evenson; Harold A. Wright; Adam E. Calihman; U. Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; Chandra Ratnasamy; Mahendra Sunkara; Jyothish Thangala; Clive Brereton; Warren Wolfs; James Lockhart

2005-10-31T23:59:59.000Z

70

Interfacial Water-Transport Effects in Proton-Exchange Membranes  

E-Print Network (OSTI)

1993, "The Contact Angle  between Water and the Surface of Desorption, and Transport of Water in  Polymer Electrolyte Vaporization?Exchange Model  for Water Sorption and Flux in 

Kienitz, Brian

2010-01-01T23:59:59.000Z

71

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (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

72

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

NLE Websites -- All DOE Office Websites (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.

73

Performance testing of hydrogen transport membranes at elevated temperatures and pressures.  

DOE Green Energy (OSTI)

The development of hydrogen transport ceramic membranes offers increased opportunities for hydrogen gas separation and utilization. Commercial application of such membranes will most likely take place under conditions of elevated temperature and pressure, where industrial processes producing and or utilizing hydrogen occur, and where such membranes are theoretically expected to have the greatest permeability. Hydrogen separation membrane performance data at elevated temperature is quite limited, and data at elevated pressures is conspicuously lacking. This paper will describe the design, construction, and recent experimental results obtained from a membrane testing unit located at the U.S. Department of Energy's Federal Energy Technology Center (FETC). The membrane testing unit is capable of operating at temperatures up to 900 C and pressures up to 500 psi. Mixed-oxide ceramic ion-transport membranes, fabricated at Argonne National Laboratory (ANL), were evaluated for hydrogen permeability and characterized for surface changes and structural integrity using scanning electron microscopy/X-ray microanalysis (SEM/EDS), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM), as a function of temperature, pressure, and hydrogen exposure.

Balachandran, U.; Cugini, A. V.; Dorris, S. E.; Fisher, E. P.; Graham, W. J.; Martello, D. V.; Poston, J. A.; Rothenberger, K. S.; Siriwardane, R. W.

1999-06-16T23:59:59.000Z

74

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUELS PLANTS  

DOE Green Energy (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. 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. This report presents hydrogen permeation data during long term tests and tests at high pressure in addition to progress with cermet, ceramic/ceramic, and thin film membranes.

Shane E. Roark; Anthony F. Sammells; Richard Mackay; Stewart Schesnack; Scott Morrison; Thomas A. Zirbel; Thomas F. Barton; Sara L. Rolfe; U. Balachandran; Richard N. Kleiner; James E. Stephan; Frank E. Anderson; Aaron L. Wagner; Jon P. Wagner

2003-07-31T23:59:59.000Z

75

Advanced Hydrogen Transport Membranes for Vision 21 Fossil Fuel Plants  

DOE Green Energy (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

76

ADVANCED HYDROGEN TRANSPORT MEMBRANES FOR VISION 21 FOSSIL FUEL PLANTS  

DOE Green Energy (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. Currently, this project is focusing on four basic categories of dense membranes: (i) mixed conducting ceramic/ceramic composites, (ii) mixed conducting ceramic/metal (cermet) composites, (iii) cermets with hydrogen permeable metals, and (iv) 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. This report describes resent results for long-term hydrogen permeation and chemical stability measurements, new mixed conducting cermets, progress in cermet, thin film, and thin-walled tube fabrication, hydrogen absorption measurements for selected compositions, and membrane facilitated alkane to olefin conversion.

Shane E. Roark; Anthony F. Sammells; Richard A. Mackay; Lyrik Y. Pitzman; Thomas A. Zirbel; Stewart 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

2003-04-30T23:59:59.000Z

77

Membrane protein kit may lead to better targeted drugs | Argonne National  

NLE Websites -- All DOE Office Websites (Extended Search)

Argonne biologists Deborah Hanson and Phil Laible developed a kit that enables its users to easily generate large amounts of membrane proteins. To view a larger version of the image, click on it. Argonne biologists Deborah Hanson and Phil Laible developed a kit that enables its users to easily generate large amounts of membrane proteins. To view a larger version of the image, click on it. Argonne biologists Deborah Hanson and Phil Laible developed a kit that enables its users to easily generate large amounts of membrane proteins. To view a larger version of the image, click on it. Filamentous cells of the bacterium Rhodobacter sphaeroides. Argonne scientists received an R&D100 Award for using Rhodobacter to develop a new system for growing membrane proteins used in drug discovery research. Image by Sheng-Wen Chui, University of Oxford. To view a larger version of the image, click on it. Filamentous cells of the bacterium Rhodobacter sphaeroides. Argonne

78

Synthesizing Membrane Proteins Using In Vitro Methodology | Argonne...  

NLE Websites -- All DOE Office Websites (Extended Search)

Proteins Using In Vitro Methodology Technology available for licensing: in vitro, cell-free expression system that caters to the production of protein types that are challenging...

79

Clusters of proteins in bio-membranes: insights into the roles of interaction potential shapes and of protein diversity  

E-Print Network (OSTI)

It has recently been proposed that proteins embedded in lipidic bio-membranes can spontaneously self-organize into stable small clusters, or membrane nano-domains, due to the competition between short-range attractive and longer-range repulsive forces between proteins, specific to these systems. In this paper, we carry on our investigation, by Monte Carlo simulations, of different aspects of cluster phases of proteins in bio-membranes. First, we compare different long-range potentials (including notably three-body terms) to demonstrate that the existence of cluster phases should be quite generic. Furthermore, a real membrane contains hundreds of different protein species that are far from being randomly distributed in these nano-domains. We take this protein diversity into account by modulating protein-protein interaction potentials both at short and longer range. We confirm theoretical predictions in terms of biological cluster specialization by deciphering how clusters recruit only a few protein species. In this respect, we highlight that cluster phases can turn out to be an advantage at the biological level, for example by enhancing the cell response to external stimuli.

Nicolas Meilhac; Nicolas Destainville

2011-06-07T23:59:59.000Z

80

Facilitated transport ceramic membranes for high-temperature gas cleanup. Final report, February 1990--April 1994  

SciTech Connect

The objective of this program was to demonstrate the feasibility of developing high temperature, high pressure, facilitated transport ceramic membranes to control gaseous contaminants in Integrated Gasification Combined Cycle (IGCC) power generation systems. Meeting this objective requires that the contaminant gas H{sub 2}S be removed from an IGCC gas mixture without a substantial loss of the other gaseous components, specifically H{sub 2} and CH{sub 4}. As described above this requires consideration of other, nonconventional types of membranes. The solution evaluated in this program involved the use of facilitated transport membranes consisting of molten mixtures of alkali and alkaline earth carbonate salts immobilized in a microporous ceramic support. To accomplish this objective, Air Products and Chemicals, Inc., Golden Technologies Company Inc., and Research Triangle Institute worked together to develop and test high temperature facilitated membranes for the removal of H{sub 2}S from IGCC gas mixtures. Three basic experimental activities were pursued: (1) evaluation of the H{sub 2}S chemistry of a variety of alkali and alkaline earth carbonate salt mixtures; (2) development of microporous ceramic materials which were chemically and physically compatible with molten carbonate salt mixtures under IGCC conditions and which could function as a host to support a molten carbonate mixture and; (3) fabrication of molten carbonate/ceramic immobilized liquid membranes and evaluation of these membranes under conditions approximating those found in the intended application. Results of these activities are presented.

Quinn, R.; Minford, E.; Damle, A.S.; Gangwal, S.K.; Hart, B.A.

1994-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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

Efficient Numerical Methods for an Anisotropic, Nonisothermal, Two-Phase Transport Model of Proton Exchange Membrane Fuel Cell  

Science Conference Proceedings (OSTI)

We carry out model and numerical studies for a three-dimensional, anisotropic, nonisothermal, two-phase steady state transport model of proton exchange membrane fuel cell (PEMFC) in this paper. Besides fully addressing the conservation equations of mass, ... Keywords: Anisotropy, Combined finite element-upwind finite volume, Kirchhoff transformation, Newton's linearization, Nonisothermality, Proton exchange membrane fuel cell (PEMFC), Two-phase transport

Pengtao Sun

2012-04-01T23:59:59.000Z

82

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

NLE Websites -- All DOE Office Websites (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

83

High-Order Membrane Complexes from Activated G-Protein Subunits  

NLE Websites -- All DOE Office Websites (Extended Search)

High-Order Membrane Complexes from Activated G-Protein Subunits Print High-Order Membrane Complexes from Activated G-Protein Subunits Print Many physiological processes initiated in response to external (extracellular) signals such as hormones, neurotransmitters, or light are regulated by a complex dance involving GTP-binding (G) proteins: G-protein-coupled receptors (GPCRs), proteins integral to the cell membrane, sense the signal and activate G proteins in the cellular cytoplasm, but enzymes such as G-protein-coupled receptor kinase 2 (GRK2) inhibit the activity of the G proteins. A joint University of Michigan-University of Illinois, Chicago, team has determined the first structure of a particular G-protein-GRK2 complex. The structure in combination with previous structures of related G-protein complexes shows how Nature has evolved the G-protein structure to not only propagate activation signals but at the same time also directly respond to regulatory proteins that control the duration of the signal.

84

High-Order Membrane Complexes from Activated G-Protein Subunits  

NLE Websites -- All DOE Office Websites (Extended Search)

High-Order Membrane Complexes from Activated G-Protein Subunits Print High-Order Membrane Complexes from Activated G-Protein Subunits Print Many physiological processes initiated in response to external (extracellular) signals such as hormones, neurotransmitters, or light are regulated by a complex dance involving GTP-binding (G) proteins: G-protein-coupled receptors (GPCRs), proteins integral to the cell membrane, sense the signal and activate G proteins in the cellular cytoplasm, but enzymes such as G-protein-coupled receptor kinase 2 (GRK2) inhibit the activity of the G proteins. A joint University of Michigan-University of Illinois, Chicago, team has determined the first structure of a particular G-protein-GRK2 complex. The structure in combination with previous structures of related G-protein complexes shows how Nature has evolved the G-protein structure to not only propagate activation signals but at the same time also directly respond to regulatory proteins that control the duration of the signal.

85

Directed transport as a mechanism for protein folding in vivo  

E-Print Network (OSTI)

We propose a model for protein folding in vivo based on a Brownian-ratchet mechanism in the multidimensional energy landscape space. The device is able to produce directed transport taking advantage of the assumed intrinsic asymmetric properties of the proteins and employing the consumption of energy provided by an external source. Through such a directed transport phenomenon, the polypeptide finds the native state starting from any initial state in the energy landscape with great efficacy and robustness, even in the presence of different type of obstacles. This model solves Levinthal's paradox without requiring biased transition probabilities but at the expense of opening the system to an external field.

Gonzalez-Candela, Ernesto

2009-01-01T23:59:59.000Z

86

Directed transport as a mechanism for protein folding in vivo  

E-Print Network (OSTI)

We propose a model for protein folding in vivo based on a Brownian-ratchet mechanism in the multidimensional energy landscape space. The device is able to produce directed transport taking advantage of the assumed intrinsic asymmetric properties of the proteins and employing the consumption of energy provided by an external source. Through such a directed transport phenomenon, the polypeptide finds the native state starting from any initial state in the energy landscape with great efficacy and robustness, even in the presence of different type of obstacles. This model solves Levinthal's paradox without requiring biased transition probabilities but at the expense of opening the system to an external field.

Ernesto Gonzalez-Candela; Victor Romero-Rochin

2009-09-23T23:59:59.000Z

87

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

88

NETL: Gasification - Development of Ion-Transport Membrane Oxygen  

NLE Websites -- All DOE Office Websites (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.

89

SEPARATION OF PROTEINS BY ION EXCHANGE AND MEMBRANE CHROMATOGRAPHY: BUFFER COMPOSITION, INTERFERING IMPURITIES AND FOULING CONSIDERATIONS  

E-Print Network (OSTI)

Efficient separation of target protein from impurities is crucial in bioseparation for large scale production and purity of the target protein. Two separation process approaches were considered in this study. The first approach focused on identifying major impurity and optimization of solution properties for target protein purification. The second approach consisted of designing an adsorbent that interacted specifically with the target molecule. The first study included modification of protein solution properties (pH, ionic strength, buffer ions) in order to maximize lysozyme purification by a strong cation exchange resin. The interaction of phytic acid, a major impurity, present in transgenic rice extracts, that contributes to decreased lysozyme adsorption capacity on SP Sepharose was evaluated. The target protein was lysozyme, which is used in a purified form as a baby formula additive to reduce gastrointestinal tract infections. At constant ionic strength, lysozyme in pH 4.5 acetate buffer had a higher binding capacity and stronger binding strength than at pH 6.0. Lysozyme in sodium phosphate buffer of pH 6.0 exhibited lower adsorption capacity than in pH 6 Tris buffer. Binding capacity and strength were significantly affected by phytic acid in all studies buffers. The second study consisted of surface modification of microfiltration membranes for protein purification and separation and reduces fouling. This study describes adsorption and fouling of chemically modified microfiltration membranes with bovine serum albumin (BSA) and immunoglobulin G (IgG). Least fouling resulted with polyethylene glycol (PEG) membranes when BSA protein was used. Amine-functionalized membranes showed specific interaction with BSA. There was multi-layer deposition of IgG on amine-functionalized membrane. G3 membrane synthesized to selectively bind IgG seemed a noble option to separate IgG from a protein mixture.

Imam, Tahmina

2009-05-01T23:59:59.000Z

90

Comparison of soy protein concentrates produced by membrane filtration and acid precipitation  

E-Print Network (OSTI)

The recovery of proteins using ultrafiltration (UF) process is an attractive alternative compared to conventional acid precipitation method. The mild processing condition, which leads to less protein denaturation, may be one of major virtues of this method. This research was directed to identify such assumptions of the products. Three soy protein concentrates were obtained in this study. Full-fat soybean flour and hexane-defatted soybean flour were dispersed into distilled water (1:8) at 60?C, respectively. A series of operations including pH adjustment (8.0), agitation (250 rpm, 30 min), sonication (40 dB, 20 min), homogenization (3 min), and centrifugation (3,000 x g, 15 min) were followed. For the membrane processing, the ultrafiltration cartridge used molecular weight cut-off 100,000 daltons. Acid-precipitated protein (at pH 4.5) was produced from hexane-defatted soybean flour following the identical procedures as above. Protein content of the membrane-processed product from full-fat soybean flour was 63.5% and that of the acid precipitated product was 71.9%. All samples were comparable in their functional properties. Nitrogen solubility at pH 7.0 was exhibited better in the protein produced by membrane filtration than the protein produced by acid precipitation due to protein denaturation. Also the membrane-processed soy protein showed good heat coagulation, emulsifying stability, and foaming stability. Amino acid patterns were similar to the typical one of soy proteins. However, relatively low lysine, threonine and valine contents in the acid-precipitated protein were noteworthy. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) patterns were almost comparable among samples. In appearance, the acid-precipitated protein was light and slightly greenish tint.

Kim, Hyun Jung

2003-01-01T23:59:59.000Z

91

Structure of a Putative Metal-Chelate Type ABC Transporter: An...  

NLE Websites -- All DOE Office Websites (Extended Search)

Putative Metal-Chelate Type ABC Transporter: An Inward-facing Conformation ATP-binding Cassette (ABC) transporters represent a large family of integral membrane proteins, which are...

92

Oxygen transport by oxygen potential gradient in dense ceramic oxide membranes  

DOE Green Energy (OSTI)

Numerous studies have been conducted in recent years on the partial oxidation of methane to synthesis gas (syngas: CO + H{sub 2}) with air as the oxidant. In partial oxidation, a mixed-oxide ceramic membrane selectively transports oxygen from the air; this transport is driven by the oxygen potential gradient. Of the several ceramic materials the authors have tested, a mixed oxide based on the Sr-Fe-Co-O system has been found to be very attractive. Extensive oxygen permeability data have been obtained for this material in methane conversion experiments carried out in a reactor. The data have been analyzed by a transport equation based on the phenomenological theory of diffusion under oxygen potential gradients. Thermodynamic calculations were used to estimate the driving force for the transport of oxygen ions. The results show that the transport equation deduced from the literature describes the permeability data reasonably well and can be used to determine the diffusion coefficients and the associated activation energy of oxygen ions in the ceramic membrane material.

Maiya, P.S.; Balachandran, U.; Dusek, J.T.; Mieville, R.L. [Argonne National Lab., IL (United States). Energy Technology Div.; Kleefisch, M.S.; Udovich, C.A. [Amoco Exploration/Production, Naperville, IL (United States)

1996-05-01T23:59:59.000Z

93

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

Science Conference Proceedings (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

94

Program on Technology Innovation: Ion Transport Membrane Oxygen Technology for Advanced Power Generation Systems  

Science Conference Proceedings (OSTI)

This report documents an Electric Power Research Institute (EPRI) Technology Innovation (TI) project that provides background information and increased understanding to EPRI members of the potential benefits of integrating ion transport membrane (ITM) technology for oxygen production with integrated gasification combined cycle (IGCC) and oxyfuel combustion pulverized coal power plants. This TI project also generated new learning by conducting literature reviews of existing and new air separation technolo...

2009-12-21T23:59:59.000Z

95

Integration of Ion Transport Membrane Technology with Oxy-Combustion Power Generation Systems  

Science Conference Proceedings (OSTI)

The Electric Power Research Institute (EPRI) in conjunction with Air Products and Chemicals, Inc., (AP) has reviewed oxy-combustion, a methodology to burn coal using oxygen rather than air to aid in removing carbon by producing a more concentrated stream of carbon dioxide (CO2) for remediation, which reduces the cost and energy required to do so. This report discusses the ion transport membrane (ITM), a technology developed by AP under a Cooperative Agreement with the United States ...

2013-09-17T23:59:59.000Z

96

Significance of Pressurized Solid Oxide Fuel Cell Hybrid Technology to Ion Transport Membranes  

Science Conference Proceedings (OSTI)

This report documents the research, history, and demonstration of pressurized solid oxide fuel cells (PSOFC)-gas turbine (GT) hybrid systems and compares and contrasts their evolution with ion transport membranes (ITM). There exists a wealth of available documentation on the PSOFC hybrid technology including multiple Electric Power Research Institute (EPRI) reports documenting these systems. This report incorporates the findings of the EPRI reports, conference proceedings, journal articles, ...

2012-12-20T23:59:59.000Z

97

Characterization of a new family of metal transport proteins. 1998 annual progress report  

Science Conference Proceedings (OSTI)

'Soils at many DOE sites are contaminated with metals and radionuclides. Such soils obviously pose a risk to human and animal health. Unlike organic wastes which can be metabolized, metals are immutable and cannot be degraded into harmless constituents. Phytoremediation, the use of plants to remove toxic materials from soil and water, may prove to be an environmentally friendly and cost effective solution for cleaning up metal-contaminated sites. The success of phytoremediation will rely on the availability of plants that absorb, translocate, and tolerate the contaminating metals. However, before the authors can engineer such plants, they need more basic information on how plants acquire metals. An important long term goal of the research program is to understand how metals such as zinc, cadmium and copper are transported across membranes. The research is focused on a new family of metal transporters which they have identified through combined studies in the yeast Saccharomyces cerevisiae and in the model plant Arabidopsis thaliana. They have identified a family of 19 presumptive metal transport genes in a variety of organisms including yeast, trypanosomes, plants, nematodes, and humans. This family, which the authors have designated the ZIP genes, provides a rich source of material with which to undertake studies on metal transport in eukaryotes. The project has three main objectives: Objective 1: Determine the sub-cellular location of the ZIP proteins in Arabidopsis. Objective 2: Carry out a structure/function analysis of the proteins encoded by the ZIP gene family to identify regions of the protein responsible for substrate specificity and affinity. Objective 3: Engineer plants to overexpress and underexpress members of the ZIP gene family and analyze these transgenic plants for alterations in metal accumulation. They now know that manipulation of transporter levels will also require an understanding of post-transcriptional control of ZIP gene expression. They are currently in year one of a three-year project.'

Guerinot, M.L.

1998-06-01T23:59:59.000Z

98

Molecular Simulations of the Effect of Cholesterol on Membrane-Mediated Protein-Protein Interactions  

E-Print Network (OSTI)

5 Molecular Simulation of the Effect of Cholesterol Protein-Properties . . . . . . . . iii 3 Molecular Simulation StudyProtein-Protein In- 4 Molecular Simulation Study of the

de Meyer, Frédérick Jean-Marie

2010-01-01T23:59:59.000Z

99

Characterization of a New Family of Metal Transport Proteins  

SciTech Connect

Soils at many DOE sites are contaminated with metals and radionuclides. Such soils obviously pose a risk to human and animal health. Unlike organic wastes, which can be metabolized, metals are immutable and cannot be degraded into harmless constituents. Phytoremediation, the use of plants to remove toxic materials from soil and water, may prove to be an environmentally friendly and cost effective solution for cleaning up metal contaminated sites. The success of phytoremediation will rely on the availability of plants that absorb, translocate, and tolerate the contaminating metals. However, before we can engineer such plants, we need more basic information on how plants acquire metals. An important long term goal of our research program is to understand how metals such as zinc, cadmium and iron are transported across membranes. Our research is focused on a new family of metal transporters, which we have identified through combined studies in the yeast Saccharomyces cerevisiae and in the model plant Arabidopsis thaliana. We have identified a family of 24 presumptive metal transport genes in a variety of organisms including yeast, trypanosomes, plants, nematodes, and humans. This family, which we have designated the ''ZIP'' genes, provides a rich source of material with which to undertake studies on metal transport in eukar

Guerinot, Mary Lou; Eide, David

1999-06-01T23:59:59.000Z

100

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

DOE Green Energy (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

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101

LDRD final report on imaging self-organization of proteins in membranes by photocatalytic nano-tagging.  

Science Conference Proceedings (OSTI)

We have developed a new nanotagging technology for detecting and imaging the self-organization of proteins and other components of membranes at nanometer resolution for the purpose of investigating cell signaling and other membrane-mediated biological processes. We used protein-, lipid-, or drug-bound porphyrin photocatalysts to grow in-situ nanometer-sized metal particles, which reveal the location of the porphyrin-labeled molecules by electron microscopy. We initially used photocatalytic nanotagging to image assembled multi-component proteins and to monitor the distribution of lipids and porphyrin labels in liposomes. For example, by exchanging the heme molecules in hemoproteins with a photocatalytic tin porphyrin, a nanoparticle was grown at each heme site of the protein. The result obtained from electron microscopy for a tagged multi-subunit protein such as hemoglobin is a symmetric constellation of a specific number of nanoparticle tags, four in the case of the hemoglobin tetramer. Methods for covalently linking photocatalytic porphyrin labels to lipids and proteins were also developed to detect and image the self-organization of lipids, protein-protein supercomplexes, and membrane-protein complexes. Procedures for making photocatalytic porphyrin-drug, porphyrin-lipid, and porphyrin-protein hybrids for non-porphyrin-binding proteins and membrane components were pursued and the first porphyrin-labeled lipids was investigated in liposomal membrane models. Our photocatalytic nanotagging technique may ultimately allow membrane self-organization and cell signaling processes to be imaged in living cells. Fluorescence and plasmonic spectra of the tagged proteins might also provide additional information about protein association and membrane organization. In addition, a porphyrin-aspirin or other NSAID hybrid may be used to grow metal nanotags for the pharmacologically important COX enzymes in membranes so that the distribution of the protein can be imaged at the nanometer scale.

Zavadil, Kevin Robert; Shelnutt, John Allen; Sasaki, Darryl Yoshio; Song, Yujiang; Medforth, Craig J.

2005-11-01T23:59:59.000Z

102

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

103

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 possessed an active area of 25, 50, and 100 cm2 with the Nafion® 117 and 115 membranes. Higher flow rates of inlet gases increase the performance of a fuel cell by increasing the removal of the water vapor, and decrease the mass transportation loss at high current density. Higher flow rates, however, result in low fuel utilization. An important factor, therefore, is to find the appropriate stoichiometric flow coefficient and starting point of stoichiometric flow rate in terms of fuel cell efficiency. Higher air supply leads to have better performance at the constant stoichiometric ratio at the anode, but not much increase after the stoichiometric ratio of 5. The effects of the environmental conditions and the channel depth for an airbreathing polymer electrolyte membrane fuel cell were investigated experimentally. Triple serpentine designs for the flow fields with two different flow depths was used. The shallow flow field deign improves dramatically the performance of the air-breathing fuel cell at low relative humidity, and slightly at high relative humidity. For proton exchange membrane fuel cells, proper water management is important to obtain maximum performance. Water management includes the humidity levels of the inlet gases as well as the understanding of the water process within the fuel cell. Two important processes associated with this understanding are (1) electro-osmotic drag of water molecules, and (2) back diffusion of the water molecules. There must be a neutral water balance over time to avoid the flooding, or drying the membranes. For these reasons, therefore, an investigation of the role of water transport in a PEM fuel cell is of particular importance. In this study, through a water balance experiment, the electro-osmotic drag coefficient was quantified and studied. For the cases where the anode was fully hydrated and the cathode suffered from the drying, when the current density was increased, the electro- osmotic drag coefficient decreased.

Park, Yong Hun

2007-12-01T23:59:59.000Z

104

Characterization of transport of calcium by microsomal membranes from roots maize  

SciTech Connect

This study investigates calcium transport by membranes of roots of maize isolated by differential centrifugation. The preparation was determined to be enriched in plasma membrane using market enzyme and electron microscopy. Using the /sup 45/Ca filtration technique and liquid scintillation counting, vesicular calcium uptake was shown to be stimulated by added calmodulin and specific for and dependent on ATP. Conditions for maximal calcium accumulation were found to be 30 min incubation in the presence of 5 mM ATP, 5 mM MgCl/sub 2/, 50 ..mu..M CaCl/sub 2/, at 23/sup 0/C, and at pH 6.5. Calcium uptake was inhibited by the ionophores A23187, X-537A, and ionomycin. Sodium fluoride, ruthenium red, and p-chloromercuribenzoate completely inhibited transport: diamide and vanadate produced slight inhibition; caffeine, caffeic acid, oligomycin, and ouabain produced little or no inhibition. Chlorpromazine, W7, trifluoperazine, and R 24 571 inhibit calcium uptake irrespective of added calmodulin, while W5 showed little effect on uptake. Verapamil, nifedipine, cinnarizine, flunarizine, lidoflazine, and diltiazem decreased calcium uptake by 17%-50%. Electron microscopic localization of calcium by pyroantimonate showed vesicles incubated with calmodulin and ATP showed the greatest amount of precipitate. These results suggest that these vesicles accumulate calcium in an ATP-dependent, calmodulin-stimulated manner.

Vaughan, M.A.

1985-01-01T23:59:59.000Z

105

Engineering Development of Ceramic Membrane Reactor System for Converting Natural Gas to Hydrogen and Synthesis Gas for Liquid Transportation Fuels  

Science Conference Proceedings (OSTI)

An Air Products-led team successfully developed ITM Syngas technology from the concept stage to a stage where a small-scale engineering prototype was about to be built. This technology produces syngas, a gas containing carbon monoxide and hydrogen, by reacting feed gas, primarily methane and steam, with oxygen that is supplied through an ion transport membrane. An ion transport membrane operates at high temperature and oxygen ions are transported through the dense membrane's crystal lattice when an oxygen partial pressure driving force is applied. This development effort solved many significant technical challenges and successfully scaled-up key aspects of the technology to prototype scale. Throughout the project life, the technology showed significant economic benefits over conventional technologies. While there are still on-going technical challenges to overcome, the progress made under the DOE-funded development project proved that the technology was viable and continued development post the DOE agreement would be warranted.

Air Products and Chemicals

2008-09-30T23:59:59.000Z

106

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

NLE Websites -- All DOE Office Websites (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

107

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

DOE Green Energy (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

108

MitoNEET is a Uniquely Folded Outer Mitochondrial Membrane Protein  

NLE Websites -- All DOE Office Websites (Extended Search)

MitoNEET is a Uniquely Folded Outer MitoNEET is a Uniquely Folded Outer Mitochondrial Membrane Protein Stabilized by Diabetes Drugs The rise in obesity in the United States parallels a dramatic increase in obesity-associated diseases, most notably type-2 diabetes. This disease is predicted to reach epidemic proportions in the next several decades (Zimmet et al 2001, Urek et al 2007). Thus, understanding the biochemical processes underlying type-2 diabetes and identifying new targets for therapeutic intervention are critical for national and world health. A drug of choice to treat type-II diabetes is pioglitazone, a thiazolidinedione (TZD) derivative originally thought to exert its effect through activation of the nuclear transcription factor PPARg. Recently, a novel protein target for pioglitazone was discovered and was called mitoNEET (Colca et al 2004). This protein is anchored to the outer mitochondrial membrane (OMM) (Wiley et al 2007). Contrary to predictions that this was a zinc-finger transcription factor we discovered that mitoNEET is a novel 2Fe-2S protein.

109

Self-Assembly and Mass Transport in Membranes for Artificial Photosynthesis  

E-Print Network (OSTI)

for artificial photosynthesis systems ..6Photosynthesis 7up process of artificial photosynthesis membranes and open

Modestino, Miguel Antonio

2013-01-01T23:59:59.000Z

110

Cargo transportation by two species of motor protein  

E-Print Network (OSTI)

The cargo motion in living cells transported by two species of motor protein with different intrinsic directionality is discussed in this study. Similar to single motor movement, cargo steps forward and backward along microtubule stochastically. Recent experiments found that, cargo transportation by two motor species has a memory, it does not change its direction as frequently as expected, which means that its forward and backward step rates depends on its previous motion trajectory. By assuming cargo has only the least memory, i.e. its step direction depends only on the direction of its last step, two cases of cargo motion are detailed analyzed in this study: {\\bf (I)} cargo motion under constant external load; and {\\bf (II)} cargo motion in one fixed optical trap. Due to the existence of memory, for the first case, cargo can keep moving in the same direction for a long distance. For the second case, the cargo will oscillate in the trap. The oscillation period decreases and the oscillation amplitude increases with the motor forward step rates, but both of them decrease with the trap stiffness. The most likely location of cargo, where the probability of finding the oscillated cargo is maximum, may be the same as or may be different with the trap center, which depends on the step rates of the two motor species. Meanwhile, if motors are robust, i.e. their forward to backward step rate ratios are high, there may be two such most likely locations, located on the two sides of the trap center respectively. The probability of finding cargo in given location, the probability of cargo in forward/backward motion state, and various mean first passage times of cargo to give location or given state are also analyzed.

Yunxin Zhang

2012-11-06T23:59:59.000Z

111

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

E-Print Network (OSTI)

Conductive Surface Area with Transport Phenomena in Proton-its bulk and interfacial transport properties as a functioninterfacial mass-transport resistance was established.

He, Qinggang

2013-01-01T23:59:59.000Z

112

Myocardial Reloading after Extracorporeal Membrane Oxygenation Alters Substrate Metabolism While Promoting Protein Synthesis  

SciTech Connect

Extracorporeal membrane oxygenation (ECMO) unloads the heart providing a bridge to recovery in children after myocardial stunning. Mortality after ECMO remains high.Cardiac substrate and amino acid requirements upon weaning are unknown and may impact recovery. We assessed the hypothesis that ventricular reloading modulates both substrate entry into the citric acid cycle (CAC) and myocardial protein synthesis. Fourteen immature piglets (7.8-15.6 kg) were separated into 2 groups based on ventricular loading status: 8 hour-ECMO (UNLOAD) and post-wean from ECMO (RELOAD). We infused [2-13C]-pyruvate as an oxidative substrate and [13C6]-L-leucine, as a tracer of amino acid oxidation and protein synthesis into the coronary artery. RELOAD showed marked elevations in myocardial oxygen consumption above baseline and UNLOAD. Pyruvate uptake was markedly increased though RELOAD decreased pyruvate contribution to oxidative CAC metabolism.RELOAD also increased absolute concentrations of all CAC intermediates, while maintaining or increasing 13C-molar percent enrichment. RELOAD also significantly increased cardiac fractional protein synthesis rates by >70% over UNLOAD. Conclusions: RELOAD produced high energy metabolic requirement and rebound protein synthesis. Relative pyruvate decarboxylation decreased with RELOAD while promoting anaplerotic pyruvate carboxylation and amino acid incorporation into protein rather than to the CAC for oxidation. These perturbations may serve as therapeutic targets to improve contractile function after ECMO.

Kajimoto, Masaki; Priddy, Colleen M.; Ledee, Dolena; Xu, Chun; Isern, Nancy G.; Olson, Aaron; Des Rosiers, Christine; Portman, Michael A.

2013-08-19T23:59:59.000Z

113

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

114

Conditions for extreme sensitivity of protein diffusion in membranes to cell environments  

E-Print Network (OSTI)

We study protein diffusion in multicomponent lipid membranes close to a rigid substrate separated by a layer of viscous fluid. The large-distance, long-time asymptotics for Brownian motion are calculated using a nonlinear stochastic Navier-Stokes equation including the effect of friction with the substrate. The advective nonlinearity, neglected in previous treatments, gives only a small correction to the renormalized viscosity and diffusion coefficient at room temperature. We find, however, that in realistic multicomponent lipid mixtures, close to a critical point for phase separation, protein diffusion acquires a strong power-law dependence on temperature and the distance to the substrate $H$, making it much more sensitive to cell environment, unlike the logarithmic dependence on $H$ and very small thermal correction away from the critical point.

Yaroslav Tserkovnyak; David R. Nelson

2006-08-11T23:59:59.000Z

115

Myocardial Oxidative Metabolism and Protein Synthesis during Mechanical Circulatory Support by Extracorporeal Membrane Oxygenation  

SciTech Connect

Extracorporeal membrane oxygenation (ECMO) provides mechanical circulatory support essential for survival in infants and children with acute cardiac decompensation. However, ECMO also causes metabolic disturbances, which contribute to total body wasting and protein loss. Cardiac stunning can also occur which prevents ECMO weaning, and contributes to high mortality. The heart may specifically undergo metabolic impairments, which influence functional recovery. We tested the hypothesis that ECMO alters oxidative. We focused on the amino acid leucine, and integration with myocardial protein synthesis. We used a translational immature swine model in which we assessed in heart (i) the fractional contribution of leucine (FcLeucine) and pyruvate (FCpyruvate) to mitochondrial acetyl-CoA formation by nuclear magnetic resonance and (ii) global protein fractional synthesis (FSR) by gas chromatography-mass spectrometry. Immature mixed breed Yorkshire male piglets (n = 22) were divided into four groups based on loading status (8 hours of normal circulation or ECMO) and intracoronary infusion [13C6,15N]-L-leucine (3.7 mM) alone or with [2-13C]-pyruvate (7.4 mM). ECMO decreased pulse pressure and correspondingly lowered myocardial oxygen consumption (~ 40%, n = 5), indicating decreased overall mitochondrial oxidative metabolism. However, FcLeucine was maintained and myocardial protein FSR was marginally increased. Pyruvate addition decreased tissue leucine enrichment, FcLeucine, and Fc for endogenous substrates as well as protein FSR. Conclusion: The heart under ECMO shows reduced oxidative metabolism of substrates, including amino acids, while maintaining (i) metabolic flexibility indicated by ability to respond to pyruvate, and (ii) a normal or increased capacity for global protein synthesis, suggesting an improved protein balance.

Priddy, MD, Colleen M.; Kajimoto, Masaki; Ledee, Dolena; Bouchard, Bertrand; Isern, Nancy G.; Olson, Aaron; Des Rosiers, Christine; Portman, Michael A.

2013-02-01T23:59:59.000Z

116

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

DOE Green Energy (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

117

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

DOE Green Energy (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

118

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

DOE Green Energy (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

119

Epithelial Membrane Protein-2 Promotes Endometrial Tumor Formation through Activation of FAK and Src  

E-Print Network (OSTI)

Endometrial cancer is the most common gynecologic malignancy diagnosed among women in developed countries. One recent biomarker strongly associated with disease progression and survival is epithelial membrane protein-2 (EMP2), a tetraspan protein known to associate with and modify surface expression of certain integrin isoforms. In this study, we show using a xenograft model system that EMP2 expression is necessary for efficient endometrial tumor formation, and we have started to characterize the mechanism by which EMP2 contributes to this malignant phenotype. In endometrial cancer cells, the focal adhesion kinase (FAK)/Src pathway appears to regulate migration as measured through wound healing assays. Manipulation of EMP2 levels in endometrial cancer cells regulates the phosphorylation of FAK and Src, and promotes their distribution into lipid raft domains. Notably, cells with low levels of EMP2 fail to migrate and poorly form tumors in vivo. These findings reveal the pivotal role of EMP2 in endometrial cancer carcinogenesis, and suggest that the association of elevated EMP2 levels with endometrial cancer prognosis may be causally linked to its effect on integrin-mediated signaling.

Maoyong Fu; Rajiv Rao; Deepthi Sudhakar; Claire P. Hogue; Zach Rutta; Shawn Morales; Lynn K; Jonathan Braun; Lee Goodglick; Madhuri Wadehra

2011-01-01T23:59:59.000Z

120

Engineering development of ceramic membrane reactor system for converting natural gas to hydrogen and synthesis gas for liquid transportation fuels  

DOE Green Energy (OSTI)

The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through June 1998.

NONE

1998-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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

Engineering development of ceramic membrane reactor system for converting natural gas to hydrogen and synthesis gas for liquid transportation fuels  

DOE Green Energy (OSTI)

The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through April 1998.

NONE

1998-05-01T23:59:59.000Z

122

ENGINEERING DEVELOPMENT OF CERAMIC MEMBRANE REACTOR SYSTEM FOR CONVERTING NATURAL GAS TO HYDROGEN AND SYNTHESIS GAS FOR LIQUID TRANSPORTATION FUELS  

DOE Green Energy (OSTI)

The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through January 2000.

NONE

2000-02-01T23:59:59.000Z

123

ENGINEERING DEVELOPMENT OF CERAMIC MEMBRANE REACTOR SYSTEM FOR CONVERTING NATURAL GAS TO HYDROGEN AND SYNTHESIS GAS FOR LIQUID TRANSPORTATION FUELS  

DOE Green Energy (OSTI)

The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through December 1999.

NONE

2000-01-01T23:59:59.000Z

124

ENGINEERING DEVELOPMENT OF CERAMIC MEMBRANE REACTOR SYSTEM FOR CONVERTING NATURAL GAS TO HYDROGEN AND SYNTHESIS GAS FOR LIQUID TRANSPORTATION FUELS  

DOE Green Energy (OSTI)

The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through October 1999.

NONE

1999-11-01T23:59:59.000Z

125

ENGINEERING DEVELOPMENT OF CERAMIC MEMBRANE REACTOR SYSTEM FOR CONVERTING NATURAL GAS TO HYDROGEN AND SYNTHESIS GAS FOR LIQUID TRANSPORTATION FUELS  

DOE Green Energy (OSTI)

The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through November 1999.

NONE

1999-12-01T23:59:59.000Z

126

ENGINEERING DEVELOPMENT OF CERAMIC MEMBRANE REACTOR SYSTEM FOR CONVERTING NATURAL GAS TO HYDROGEN AND SYNTHESIS GAS FOR LIQUID TRANSPORTATION FUELS  

DOE Green Energy (OSTI)

The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through February 1999.

NONE

1999-03-01T23:59:59.000Z

127

ENGINEERING DEVELOPMENT OF CERAMIC MEMBRANE REACTOR SYSTEM FOR CONVERTING NATURAL GAS TO HYDROGEN AND SYNTHESIS GAS FOR LIQUID TRANSPORTATION FUELS  

DOE Green Energy (OSTI)

The objective of this contract is to research, develop and demonstrate a novel ceramic membrane reactor system for the low-cost conversion of natural gas to synthesis gas and hydrogen for liquid transportation fuels: the ITM Syngas process. Through an eight-year, three-phase program, the technology will be developed and scaled up to obtain the technical, engineering, operating and economic data necessary for the final step to full commercialization of the Gas-to-Liquids (GTL) conversion technology. This report is a summary of activities through September 1999.

NONE

1999-10-01T23:59:59.000Z

128

NMR studies of methanol transport in membranes for fuel cell applications.  

DOE Green Energy (OSTI)

Characterization of the methanol diffusion process in Nafion 117 was achieved with the use of a modified pulsed field gradient NMR technique. To ensure that the concentration of methanol was constant throughout the entire experiment, the membrane was continually immersed in the methanol solution. When using the standard pulsed field gradient NMR method, the diffusion of the methanol in the membrane is strongly influenced by the diffusion of methanol in solution. Application of a filter gradient suppresses the signal from the methanol in solution, enabling the methanol diffusion in the membrane to be observed unambiguously. Complete suppression of the solution signal was achieved when a 60% filter gradient was employed. Under such circumstances, the coefficient for diffusion of methanol within the membrane was calculated to be 4x10-6cm2s-1, which is similar to the values reported in the literature. Consequently, the use of NMR filter gradient measurements is a valid method for studying the diffusion coefficient of methanol within fuel cell membranes.

Every, H. A. (Hayley A.); Zawodzinski, T. A. (Thomas A.), Jr.

2001-01-01T23:59:59.000Z

129

Super Boiler: Packed Media/Transport Membrane Boiler Development and Demonstration  

Science Conference Proceedings (OSTI)

Gas Technology Institute (GTI) and Cleaver-Brooks developed a new gas-fired steam generation system���¢��������the Super Boiler���¢��������for increased energy efficiency, reduced equipment size, and reduced emissions. The system consists of a firetube boiler with a unique staged furnace design, a two-stage burner system with engineered internal recirculation and inter-stage cooling integral to the boiler, unique convective pass design with extended internal surfaces for enhanced heat transfer, and a novel integrated heat recovery system to extract maximum energy from the flue gas. With these combined innovations, the Super Boiler technical goals were set at 94% HHV fuel efficiency, operation on natural gas with boilers of similar steam output. To demonstrate these technical goals, the project culminated in the industrial demonstration of this new high-efficiency technology on a 300 HP boiler at Clement Pappas, a juice bottler located in Ontario, California. The Super Boiler combustion system is based on two stage combustion which combines air staging, internal flue gas recirculation, inter-stage cooling, and unique fuel-air mixing technology to achieve low emissions rather than external flue gas recirculation which is most commonly used today. The two-stage combustion provides lower emissions because of the integrated design of the boiler and combustion system which permit precise control of peak flame temperatures in both primary and secondary stages of combustion. To reduce equipment size, the Super Boiler's dual furnace design increases radiant heat transfer to the furnace walls, allowing shorter overall furnace length, and also employs convective tubes with extended surfaces that increase heat transfer by up to 18-fold compared to conventional bare tubes. In this way, a two-pass boiler can achieve the same efficiency as a traditional three or four-pass firetube boiler design. The Super Boiler is consequently up to 50% smaller in footprint, has a smaller diameter, and is up to 50% lower in weight, resulting in very compact design with reduced material cost and labor costs, while requiring less boiler room floor space. For enhanced energy efficiency, the heat recovery system uses a transport membrane condenser (TMC), a humidifying air heater (HAH), and a split-stage economizer to extract maximum energy from the flue gas. The TMC is a new innovation that pulls a major portion of water vapor produced by the combustion process from the flue gases along with its sensible and latent heat. This results in nearly 100% transfer of heat to the boiler feed water. The HAH improves the effectiveness of the TMC, particularly in steam systems that do not have a large amount of cold makeup water. In addition, the HAH humidifies the combustion air to reduce NOx formation. The split-stage economizer preheats boiler feed water in the same way as a conventional economizer, but extracts more heat by working in tandem with the TMC and HAH to reduce flue gas temperature. These components are designed to work synergistically to achieve energy efficiencies of 92-94% which is 10-15% higher than today���¢��������s typical firetube boilers.

Liss, William E; Cygan, David F

2013-04-17T23:59:59.000Z

130

Super Boiler: Packed Media/Transport Membrane Boiler Development and Demonstration  

SciTech Connect

Gas Technology Institute (GTI) and Cleaver-Brooks developed a new gas-fired steam generation system���¢��������the Super Boiler���¢��������for increased energy efficiency, reduced equipment size, and reduced emissions. The system consists of a firetube boiler with a unique staged furnace design, a two-stage burner system with engineered internal recirculation and inter-stage cooling integral to the boiler, unique convective pass design with extended internal surfaces for enhanced heat transfer, and a novel integrated heat recovery system to extract maximum energy from the flue gas. With these combined innovations, the Super Boiler technical goals were set at 94% HHV fuel efficiency, operation on natural gas with <5 ppmv NOx (referenced to 3%O2), and 50% smaller than conventional boilers of similar steam output. To demonstrate these technical goals, the project culminated in the industrial demonstration of this new high-efficiency technology on a 300 HP boiler at Clement Pappas, a juice bottler located in Ontario, California. The Super Boiler combustion system is based on two stage combustion which combines air staging, internal flue gas recirculation, inter-stage cooling, and unique fuel-air mixing technology to achieve low emissions rather than external flue gas recirculation which is most commonly used today. The two-stage combustion provides lower emissions because of the integrated design of the boiler and combustion system which permit precise control of peak flame temperatures in both primary and secondary stages of combustion. To reduce equipment size, the Super Boiler's dual furnace design increases radiant heat transfer to the furnace walls, allowing shorter overall furnace length, and also employs convective tubes with extended surfaces that increase heat transfer by up to 18-fold compared to conventional bare tubes. In this way, a two-pass boiler can achieve the same efficiency as a traditional three or four-pass firetube boiler design. The Super Boiler is consequently up to 50% smaller in footprint, has a smaller diameter, and is up to 50% lower in weight, resulting in very compact design with reduced material cost and labor costs, while requiring less boiler room floor space. For enhanced energy efficiency, the heat recovery system uses a transport membrane condenser (TMC), a humidifying air heater (HAH), and a split-stage economizer to extract maximum energy from the flue gas. The TMC is a new innovation that pulls a major portion of water vapor produced by the combustion process from the flue gases along with its sensible and latent heat. This results in nearly 100% transfer of heat to the boiler feed water. The HAH improves the effectiveness of the TMC, particularly in steam systems that do not have a large amount of cold makeup water. In addition, the HAH humidifies the combustion air to reduce NOx formation. The split-stage economizer preheats boiler feed water in the same way as a conventional economizer, but extracts more heat by working in tandem with the TMC and HAH to reduce flue gas temperature. These components are designed to work synergistically to achieve energy efficiencies of 92-94% which is 10-15% higher than today���¢��������s typical firetube boilers.

Liss, William E; Cygan, David F

2013-04-17T23:59:59.000Z

131

Evaluation of active transport membranes for carbon dioxide removal from hydrogen containing streams. Approved final topical report  

SciTech Connect

Air Products and Chemicals, Inc. is developing a new class of gas separation membranes called Active Transport Membranes (ATM). ATMs are unique in that they permeate acid gas components, via a reactive pathway, to the low pressure side of the membrane while retaining lighter, non-reactive gases at near feed pressure. This feature is intuitively attractive for hydrogen and synthesis gas processes where CO{sub 2} removal is desired and the hydrogen or synthesis gas product is to be used at elevated pressure. This report provides an overview of the technology status and reports on preliminary, order of magnitude assessments of ATMs for three applications requiring CO{sub 2} removal from gas streams containing hydrogen. The end uses evaluated are: CO{sub 2} removal in the COREX{reg_sign} Steel making process--upgrading export gas for a Direct Reducing Iron (DRI) process; CO{sub 2} removal for onboard hydrogen gas generators for mobile fuel cell applications; Bulk CO{sub 2} removal from hydrogen plant synthesis gas--a plant de-bottlenecking analysis for ammonia production. For each application, an overview of the process concept, rough equipment sizing and techno-economic evaluation against competing technologies is provided. Brief descriptions of US and world market conditions are also included.

Cook, P.J.; Laciak, D.V.; Pez, G.P.; Quinn, R.

1995-11-01T23:59:59.000Z

132

Lipid Dynamics and Protein–Lipid Interactions in 2D Crystals Formed with the ?-Barrel Integral Membrane Protein VDAC1  

E-Print Network (OSTI)

We employ a combination of [superscript 13]C/[superscript 15]N magic angle spinning (MAS) NMR and [superscript 2]H NMR to study the structural and functional consequences of different membrane environments on VDAC1 and, ...

Ong, Ta-Chung

133

The organization of the gene (EPB72) encoding the human erythrocyte band 7 integral membrane protein (protein 7.2b)  

Science Conference Proceedings (OSTI)

The human gene EPB72 coding for the band 7 integral membrane protein, a major protein of the erythrocyte membrane membrane, was isolated from a genomic DNA library and characterized. Spanning {approximately}30 kb, the human EPB72 gene comprises seven exons; intron sizes range from 970 to {approximately}11,200 bp. The first exon contains the 5{prime}-untranslated region (61 nucleotides) and the coding sequence for the N-terminal domain; the second exon encodes the hydrophobic domain, including flanking cysteine and lysine residues. Exon 7 contains the C-terminal portion and a 2-kb 3{prime}-untranslated region. The potential promoter region contains several consensus sequences for ubiquitous transcription factors (Sp1, AP1, AP2, CP1/2, NF{kappa}B, CREB, Ets-1, and CACC/GT-BF) and two imperfect sequences for erythroid factors (EKLF and GATA-1), in accordance with the ubiquitous distribution of the EPB72 mRNA in different cell types. No TATA box was apparent. An inverted Alu repeat element, flanked by nonamer direct repeats, was identified within the region -913/-620, relative to the cap site. Six additional Alu repeat elements, including one monomer and one trimer, were identified within the introns and the 3{prime}-untranslated region. Two polyadenylation signals in the 3{prime}-noncoding region of exon 7 enable the production of two mRNA species. 45 refs., 3 figs., 2 tabs.

Unfried, I.; Entler, B.; Prohaska, R. [Univ. of Vienna (Austria)] [Univ. of Vienna (Austria)

1995-12-10T23:59:59.000Z

134

Crystal Structure of Dengue Virus Type 1 Envelope Protein in the Postfusion Conformation and Its Implications for Membrane Fusion  

SciTech Connect

Dengue virus relies on a conformational change in its envelope protein, E, to fuse the viral lipid membrane with the endosomal membrane and thereby deliver the viral genome into the cytosol. We have determined the crystal structure of a soluble fragment E (sE) of dengue virus type 1 (DEN-1). The protein is in the postfusion conformation even though it was not exposed to a lipid membrane or detergent. At the domain I-domain III interface, 4 polar residues form a tight cluster that is absent in other flaviviral postfusion structures. Two of these residues, His-282 and His-317, are conserved in flaviviruses and are part of the 'pH sensor' that triggers the fusogenic conformational change in E, at the reduced pH of the endosome. In the fusion loop, Phe-108 adopts a distinct conformation, forming additional trimer contacts and filling the bowl-shaped concavity observed at the tip of the DEN-2 sE trimer.

Nayak, Vinod; Dessau, Moshe; Kucera, Kaury; Anthony, Karen; Ledizet, Michel; Modis, Yorgo; (Yale); (L2 Diagnostics)

2009-07-31T23:59:59.000Z

135

Molecular Mechanism of Biological Proton Transport  

Science Conference Proceedings (OSTI)

Proton transport across lipid membranes is a fundamental aspect of biological energy transduction (metabolism). This function is mediated by a Grotthuss mechanism involving proton hopping along hydrogen-bonded networks embedded in membrane-spanning proteins. Using molecular simulations, the authors have explored the structural, dynamic, and thermodynamic properties giving rise to long-range proton translocation in hydrogen-bonded networks involving water molecules, or water wires, which are emerging as ubiquitous H{sup +}-transport devices in biological systems.

Pomes, R.

1998-09-01T23:59:59.000Z

136

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

DOE Green Energy (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

137

Proton and methanol transport in poly(perfluorosulfonate) membranes containing Cs{sup +} and H{sup +} cations  

Science Conference Proceedings (OSTI)

Poly(perfluorosulfonate acid) membranes were doped with cesium ions to several degrees. These, along with the H{sup +}-form membrane, were investigated in relation to methanol permeability as well as hydrogen ion conductivity. While retaining considerable conductivity, the cesium-doped membranes are highly impermeable to methanol. The author found that methanol permeability in the membrane reduced by over one order of magnitude, owing to the presence of cesium ions. These findings are discussed on the basis of alterations produced by cesium in the membrane microstructure. Also discussed is the potential implication of these results in the direct methanol fuel cell technology.

Tricoli, V. [Univ. of Pisa (Italy)

1998-11-01T23:59:59.000Z

138

NMR structural and functional studies of the mithochondrial outer membrane protein VDAC by Thomas J. Malia.  

E-Print Network (OSTI)

Apoptosis is a mechanism of programmed cell death required by multicellular organisms during development and for tissue maintenance. Bcl-2 family proteins are central regulators of apoptosis and many of their primary roles ...

Malia, Thomas J., 1977-

2006-01-01T23:59:59.000Z

139

Transportation  

NLE Websites -- All DOE Office Websites (Extended Search)

Transportation banner Home Agenda Awards Exhibitors Lodging Posters Registration T-Shirt Contest Transportation Workshops Contact Us User Meeting Archives Users' Executive...

140

Transportation  

NLE Websites -- All DOE Office Websites (Extended Search)

Transportation Print banner Home Agenda Awards Exhibitors Lodging Posters Registration T-Shirt Contest Transportation Workshops Contact Us User Meeting Archives Users' Executive...

Note: This page contains sample records for the topic "membrane transport proteins" 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

Transportation  

NLE Websites -- All DOE Office Websites (Extended Search)

Links Transportation and Air Quality Transportation Energy Policy Analysis Batteries and Fuel Cells Buildings Energy Efficiency Electricity Grid Energy Analysis Appliance Energy...

142

Control systems for membrane fusion in the ancestral eukaryote; evolution of tethering complexes and SM proteins  

E-Print Network (OSTI)

bud- ding. For example, distant but clear homology exists between coatomer, clathrin and adaptin proteins, while a conserved architecture has recently been uncovered for proteins of the nuclear pore complex and the clathrin coat system [14... this figure as it is only found in S. cerevisiae. O pi st ok on ta A m oe bo zo a Ex ca va ta A rc ha ep la st id a Ch ro m al ve ol at a BMC Evolutionary Biology 2007, 7:29 http://www.biomedcentral.com/1471-2148/7/29 selection pressure for TRAPP subunits may...

Koumandou, V Lila; Dacks, Joel B; Coulson, Richard M R; Field, Mark C

2007-02-23T23:59:59.000Z

143

Transportation  

NLE Websites -- All DOE Office Websites (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.

144

Different activities of the reovirus FAST proteins and influenza hemagglutinin in cell-cell fusion assays and in response to membrane curvature agents  

SciTech Connect

The reovirus fusion-associated small transmembrane (FAST) proteins evolved to induce cell-cell, rather than virus-cell, membrane fusion. It is unclear whether the FAST protein fusion reaction proceeds in the same manner as the enveloped virus fusion proteins. We now show that fluorescence-based cell-cell and cell-RBC hemifusion assays are unsuited for detecting lipid mixing in the absence of content mixing during FAST protein-mediated membrane fusion. Furthermore, membrane curvature agents that inhibit hemifusion or promote pore formation mediated by influenza hemagglutinin had no effect on p14-induced cell-cell fusion, even under conditions of limiting p14 concentrations. Standard assays used to detect fusion intermediates induced by enveloped virus fusion proteins are therefore not applicable to the FAST proteins. These results suggest the possibility that the nature of the fusion intermediates or the mechanisms used to transit through the various stages of the fusion reaction may differ between these distinct classes of viral fusogens.

Clancy, Eileen K.; Barry, Chris; Ciechonska, Marta [Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, B3H 1X5 (Canada); Duncan, Roy, E-mail: roy.duncan@dal.c [Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, B3H 1X5 (Canada); Department of Pediatrics, Dalhousie University, Halifax, Nova Scotia, B3H 1X5 (Canada)

2010-02-05T23:59:59.000Z

145

OXYGEN TRANSPORT CERAMIC MEMBRANES  

DOE Green Energy (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

146

Transportation  

NLE Websites -- All DOE Office Websites (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

147

Transportation  

Science Conference Proceedings (OSTI)

Transportation systems are an often overlooked critical infrastructure component. These systems comprise a widely diverse elements whose operation impact all aspects of society today. This chapter introduces the key transportation sectors and illustrates ...

Mark Hartong; Rajn Goel; Duminda Wijesekera

2012-01-01T23:59:59.000Z

148

Reduction of Nitrate in Shewanella oneidensis depends on atypical NAP and NRF systems with NapB as a preferred electron transport protein from CymA to NapA  

SciTech Connect

In the genome of Shewanella oneidensis, a napDAGHB gene cluster encoding periplasmic nitrate reductase (NapA) and accessory proteins and an nrfA gene encoding periplasmic nitrite reductase (NrfA) have been identified. These two systems seem to be atypical because the genome lacks genes encoding cytoplasmic membrane electron transport proteins, NapC for NAP and NrfBCD/NrfH for NRF, respectively. Here, we present evidence that reduction of nitrate to ammonium in S. oneidensis is carried out by these atypical systems in a two-step manner. Transcriptional and mutational analyses suggest that CymA, a cytoplasmic membrane electron transport protein, is likely to be the functional replacement of both NapC and NrfH in S. oneidensis. Surprisingly, a strain devoid of napB encoding the small subunit of nitrate reductase exhibited the maximum cell density sooner than the wild type. Further characterization of this strain showed that nitrite was not detected as a free intermediate in its culture and NapB provides a fitness gain for S. oneidensis to compete for nitrate in the environments. On the basis results from mutational analyses of napA, napB, nrfA and napBnrfA in-frame deletion mutants, we propose that NapB is able to favor nitrate reduction by routing electrons to NapA exclusively.

Gao, Haichun; Yang, Zamin; Barua, Soumitra; Reed, Samantha B.; Romine, Margaret F.; Nealson, Kenneth H.; Fredrickson, Jim K.; Tiedje, James M.; Zhou, Jizhong

2009-04-23T23:59:59.000Z

149

Operation of staged membrane oxidation reactor systems  

DOE Patents (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

150

Transportation  

NLE Websites -- All DOE Office Websites (Extended Search)

Meier AKMeier@lbl.gov (510) 486-4740 Links Transportation and Air Quality Batteries and Fuel Cells Buildings Energy Efficiency Electricity Grid Energy Analysis Energy...

151

In Vivo Identification of the Outer Membrane Protein OmcA-MtrC Interaction Network in Shewanella oneidensis MR-1 Cells Using Novel Hydrophobic Chemical Cross-Linkers  

SciTech Connect

Outer membrane (OM) cytochromes OmcA (SO1779) and MtrC (SO1778) are the integral components of electron transfer used by Shewanella oneidensis for anaerobic respiration of metal (hydr)oxides. Here the OmcA-MtrC interaction was identified in vivo using a novel hydrophobic chemical cross-linker (MRN) combined with immunoprecipitation techniques. In addition, identification of other OM proteins from the cross-linked complexes allows first visualization of the OmcA-MtrC interaction network. Further experiments on omcA and mtrC mutant cells showed OmcA plays a central role in the network interaction. For comparison, two commercial cross-linkers were also used in parallel and both resulted in fewer OM protein identifications, indicating the superior properties of MRN for identification of membrane protein interactions. Finally, comparison experiments of in vivo cross-linking and cell lysate cross-linking resulted in significantly different protein interaction data, demonstrating the importance of in vivo cross-linking for study of protein-protein interactions in cells.

Zhang, Haizhen; Tang, Xiaoting; Munske, Gerhard R.; Zakharova, Natalia L.; Yang, Li; Zheng, Chunxiang; Wolff, Meagan A.; Tolic, Nikola; Anderson, Gordon A.; Shi, Liang; Marshall, Matthew J.; Fredrickson, Jim K.; Bruce, James E.

2008-04-01T23:59:59.000Z

152

Targeted Protein Degradation of Outer Membrane Decaheme Cytochrome MtrC Metal Reductase in Shewanella oneidensis MR-1 Measured Using Biarsenical Probe CrAsH-EDT2  

SciTech Connect

Development of efficient microbial biofuel cells requires an ability to exploit interfacial electron transfer reactions to external electron acceptors, such as metal oxides; such reactions occur in the facultative anaerobic gram-negative bacterium Shewanella oneidensis MR-1 through the catalytic activity of the outer membrane decaheme c-type cytochrome MtrC. Central to the utility of this pathway to synthetic biology is an understanding of cellular mechanisms that maintain optimal MtrC function, cellular localization, and renewal by degradation and resynthesis. In order to monitor trafficking to the outer membrane, and the environmental sensitivity of MtrC, we have engineered a tetracysteine tag (i.e., CCPGCC) at its C-terminus that permits labeling by the cell impermeable biarsenical fluorophore, carboxy-FlAsH (CrAsH) of MtrC at the surface of living Shewanella oneidensis MR-1 cells. In comparison, the cell permeable reagent FlAsH permits labeling of the entire population of MtrC, including proteolytic fragments resulting from incorrect maturation. We demonstrate specific labeling by CrAsH of engineered MtrC which is dependent on the presence of a functional type-2 secretion system (T2S), as evidenced by T2S system gspD or gspG deletion mutants which are incapable of CrAsH labeling. Under these latter conditions, MtrC undergoes proteolytic degradation to form a large 35-38 kDa fragment; this degradation product is also resolved during normal turnover of the CrAsH-labeled MtrC protein. No MtrC protein is released into the medium during turnover, suggesting the presence of cellular turnover systems involving MtrC reuptake and degradation. The mature MtrC localized on the outer membrane is a long-lived protein, with a turnover rate of 0.043 hr-1 that is insensitive to O2 concentration. Maturation of MtrC is relatively inefficient, with substantial rates of turnover of the immature protein prior to export to the outer membrane (i.e., 0.028 hr-1) that are consistent with the inherent complexity associated with correct heme insertion and acylation of MtrC that occurs in the periplasm prior to its targeting to the outer membrane. These latter results suggest that MtrC protein trafficking to the outer membrane and its subsequent degradation are tightly regulated, which is consistent with cellular processing pathways that target MtrC to extracellular structures and their possible role in promoting electron transfer from Shewanella to extracellular acceptors.

Xiong, Yijia; Chen, Baowei; Shi, Liang; Fredrickson, Jim K.; Bigelow, Diana J.; Squier, Thomas C.

2011-10-14T23:59:59.000Z

153

Understanding Protein Membranes  

Office of Scientific and Technical Information (OSTI)

Explorer Loading... Stop news scroll Most Visited Adopt-A-Doc DOE Data Explorer DOE Green Energy DOepatents DOE R&D Accomplishments .EDUconnections Energy Citations Database...

154

IONICALLY CONDUCTING MEMBRANES FOR HYDROGEN PRODUCTION AND  

E-Print Network (OSTI)

SEQUESTRATION Oxygen Transport Membrane Hydrogen Transport Membrane Natural Gas Coal Biomass Syngas CO/H2 WGS H2 operating experience. #12;ELTRON RESEARCH INC. Syngas Production Rate ­ 60 mL/min cm2 @ 900°C Equivalent O2 Operational Experience Under High Pressure Differential SUMMARY OF ELTRON OXYGEN TRANSPORT MEMBRANE SYNGAS

155

Transportation  

NLE Websites -- All DOE Office Websites (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.

156

Research and Development of Proton-Exchange Membrane (PEM) Fuel Cell System for Transportation Applications: Initial Conceptual Design Report  

DOE Green Energy (OSTI)

This report addresses Task 1.1, model development and application, and Task 1.2, vehicle mission definition. Overall intent is to produce a methanol-fueled 10-kW power source, and to evaluate electrochemical engine (ECE) use in transportation. Major achievements include development of an ECE power source model and its integration into a comprehensive power source/electric vehicle propulsion model, establishment of candidate FCV (fuel cell powered electric vehicle) mission requirements, initial FCV studies, and a candidate FCV recommendation for further study.

Not Available

1993-11-30T23:59:59.000Z

157

Entropic Tension in Crowded Membranes  

E-Print Network (OSTI)

Unlike their model membrane counterparts, biological membranes are richly decorated with a heterogeneous assembly of membrane proteins. These proteins are so tightly packed that their excluded area interactions can alter the free energy landscape controlling the conformational transitions suffered by such proteins. For membrane channels, this effect can alter the critical membrane tension at which they undergo a transition from a closed to an open state, and therefore influence protein function in vivo. Despite their obvious importance, crowding phenomena in membranes are much less well studied than in the cytoplasm. Using statistical mechanics results for hard disk liquids, we show that crowding induces an entropic tension in the membrane, which influences transitions that alter the projected area and circumference of a membrane protein. As a specific case study in this effect, we consider the impact of crowding on the gating properties of bacterial mechanosensitive membrane channels, which are thought to confer osmoprotection when these cells are subjected to osmotic shock. We find that crowding can alter the gating energies by more than 2 kBT in physiological conditions, a substantial fraction of the total gating energies in some cases. Given the ubiquity of membrane crowding, the nonspecific nature of excluded volume interactions, and the fact that the function of many membrane proteins involve significant

Martin Lindén; Pierre Sens; Rob Phillips

2012-01-01T23:59:59.000Z

158

Identification and Structural Analysis of a Novel Carboxysome Shell Protein with Implications for Metabolite Transport  

E-Print Network (OSTI)

Bacterial microcompartments (BMCs) are polyhedral bodies, composed entirely of proteins, that function as organelles in bacteria; they promote subcellular processes by encapsulating and co-localizing targeted enzymes with ...

Klein, Michael G.

159

Ninth International Workshop on Plant Membrane Biology  

SciTech Connect

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

160

Defects and Transport I  

Science Conference Proceedings (OSTI)

Oct 8, 2012 ... Secondary Transport Phenomena in Ceramic Membranes under ... the specific case of mixed proton/oxygen vacancy/electronic conduction in a ...

Note: This page contains sample records for the topic "membrane transport proteins" 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

Modeling diffusional transport in the interphase cell nucleus Annika Wedemeier  

E-Print Network (OSTI)

of Physics, Xiamen University, Xiamen 361005, People's Republic of China and ITPA Xiamen University, Xiamen 361005, People's Republic of China Jörg Langowski Deutsches Krebsforschungszentrum, D-69120 Heidelberg alive:1,2 Molecules transported through cell membranes, drugs on their way to their protein recep- tors

Langowski, Jörg

162

Intra-membrane molecular interactions of K%2B channel proteins : application to problems in biodefense and bioenergy.  

SciTech Connect

Ion channel proteins regulate complex patterns of cellular electrical activity and ionic signaling. Certain K+ channels play an important role in immunological biodefense mechanisms of adaptive and innate immunity. Most ion channel proteins are oligomeric complexes with the conductive pore located at the central subunit interface. The long-term activity of many K+ channel proteins is dependent on the concentration of extracellular K+; however, the mechanism is unclear. Thus, this project focused on mechanisms underlying structural stability of tetrameric K+ channels. Using KcsA of Streptomyces lividans as a model K+ channel of known structure, the molecular basis of tetramer stability was investigated by: 1. Bioinformatic analysis of the tetramer interface. 2. Effect of two local anesthetics (lidocaine, tetracaine) on tetramer stability. 3. Molecular simulation of drug docking to the ion conduction pore. The results provide new insights regarding the structural stability of K+ channels and its possible role in cell physiology.

Moczydlowski, Edward G.

2013-07-01T23:59:59.000Z

163

TRANSPORTATION TRANSPORTATION  

E-Print Network (OSTI)

TEXASTRANS TEXAS TRANSPORTATION HALL HONOR OF HALL HONOR OF TEXASTRAN HALL HONOR OF TEXASTRAN HALL HONOR OF Inductees #12;2 TEXAS TRANSPORTATION HALL HONOR OF L NOR OF Texas is recognized as having one of the finest multimodal transportation systems in the world. The existence of this system has been key

164

Visualization of the African swine fever virus infection in living cells by incorporation into the virus particle of green fluorescent protein-p54 membrane protein chimera  

SciTech Connect

Many stages of African swine fever virus infection have not yet been studied in detail. To track the behavior of African swine fever virus (ASFV) in the infected cells in real time, we produced an infectious recombinant ASFV (B54GFP-2) that expresses and incorporates into the virus particle a chimera of the p54 envelope protein fused to the enhanced green fluorescent protein (EGFP). The incorporation of the fusion protein into the virus particle was confirmed immunologically and it was determined that p54-EGFP was fully functional by confirmation that the recombinant virus made normal-sized plaques and presented similar growth curves to the wild-type virus. The tagged virus was visualized as individual fluorescent particles during the first stages of infection and allowed to visualize the infection progression in living cells through the viral life cycle by confocal microscopy. In this work, diverse potential applications of B54GFP-2 to study different aspects of ASFV infection are shown. By using this recombinant virus it was possible to determine the trajectory and speed of intracellular virus movement. Additionally, we have been able to visualize for first time the ASFV factory formation dynamics and the cytophatic effect of the virus in live infected cells. Finally, we have analyzed virus progression along the infection cycle and infected cell death as time-lapse animations.

Hernaez, Bruno [Departamento de Biotecnologia, INIA, Carretera de la Coruna Km 7, 28040 Madrid (Spain)]. E-mail: hernaez@inia.es; Escribano, Jose M. [Departamento de Biotecnologia, INIA, Carretera de la Coruna Km 7, 28040 Madrid (Spain)]. E-mail: escriban@inia.es; Alonso, Covadonga [Departamento de Biotecnologia, INIA, Carretera de la Coruna Km 7, 28040 Madrid (Spain)]. E-mail: calonso@inia.es

2006-06-20T23:59:59.000Z

165

Direct-hydrogen-fueled proton-exchange-membrane fuel cell system for transportation applications: Conceptual vehicle design report pure fuel cell powertrain vehicle  

SciTech Connect

In partial fulfillment of the Department of Energy (DOE) Contract No. DE-AC02-94CE50389, {open_quotes}Direct-Hydrogen-Fueled Proton-Exchange-Membrane (PEM) Fuel Cell for Transportation Applications{close_quotes}, this preliminary report addresses the conceptual design and packaging of a fuel cell-only powered vehicle. Three classes of vehicles are considered in this design and packaging exercise, the Aspire representing the small vehicle class, the Taurus or Aluminum Intensive Vehicle (AIV) Sable representing the mid-size vehicle and the E-150 Econoline representing the van-size class. A fuel cell system spreadsheet model and Ford`s Corporate Vehicle Simulation Program (CVSP) were utilized to determine the size and the weight of the fuel cell required to power a particular size vehicle. The fuel cell power system must meet the required performance criteria for each vehicle. In this vehicle design and packaging exercise, the following assumptions were made: fuel cell power system density of 0.33 kW/kg and 0.33 kg/liter, platinum catalyst loading less than or equal to 0.25 mg/cm{sup 2} total and hydrogen tanks containing gaseous hydrogen under 340 atm (5000 psia) pressure. The fuel cell power system includes gas conditioning, thermal management, humidity control, and blowers or compressors, where appropriate. This conceptual design of a fuel cell-only powered vehicle will help in the determination of the propulsion system requirements for a vehicle powered by a PEMFC engine in lieu of the internal combustion (IC) engine. Only basic performance level requirements are considered for the three classes of vehicles in this report. Each vehicle will contain one or more hydrogen storage tanks and hydrogen fuel for 560 km (350 mi) driving range. Under these circumstances, the packaging of a fuel cell-only powered vehicle is increasingly difficult as the vehicle size diminishes.

Oei, D.; Kinnelly, A.; Sims, R.; Sulek, M.; Wernette, D.

1997-02-01T23:59:59.000Z

166

Quantitative analysis of intra-Golgi transport reveals inter-cisternal exchange for all cargo  

E-Print Network (OSTI)

The mechanisms controlling the transport of proteins across the Golgi stack of mammalian and plant cells is the subject of intense debate, with two models, cisternal progression and inter-cisternal exchange, emerging as major contenders. A variety of transport experiments have claimed support for each of these models. We reevaluate these experiments using a single quantitative coarse-grained framework of intra-Golgi transport that accounts for both transport models and their many variants. Our analysis makes a definitive case for the existence of inter-cisternal exchange both for small membrane proteins (VSVG) and large protein complexes (procollagen) -- this implies that membrane structures larger than the typical protein-coated vesicles must be involved in transport. Notwithstanding, we find that current observations on protein transport cannot rule out cisternal progression as contributing significantly to the transport process. To discriminate between the different models of intra-Golgi transport, we suggest experiments and an analysis based on our extended theoretical framework that compare the dynamics of transiting and resident proteins.

Serge Dmitrieff; Madan Rao; Pierre Sens

2013-07-26T23:59:59.000Z

167

Proteins  

NLE Websites -- All DOE Office Websites (Extended Search)

Proteins Proteins Scientists manipulate and mimic proteins for use in creating solutions for medicine, sustainable energy, and more Read caption + Los Alamos National Laboratory graduate student, Patricia Langan, changes the properties of a green fluorescent protein in order to create new fluorescent protein variants. Overview of Research and Highlights Scientists at Los Alamos apply a unique collection of tools and expertise to gain a comprehensive understanding of the structure and function of proteins as well as to manipulate and mimic proteins for use in research. This knowledge can lead to a multitude of possibilities, such as enhancing cellulose degradation for biofuels based on understanding the enzymes that naturally degrade it (cellulases) or creating new therapeutics for tuberculosis patients.

168

Membrane stabilizer  

DOE Patents (OSTI)

A device is provided for stabilizing a flexible membrane secured within a frame, wherein a plurality of elongated arms are disposed radially from a central hub which penetrates the membrane, said arms imposing alternately against opposite sides of the membrane, thus warping and tensioning the membrane into a condition of improved stability. The membrane may be an opaque or translucent sheet or other material. 10 figs.

Mingenbach, W.A.

1988-02-09T23:59:59.000Z

169

Diffusion through Carbon Nanotube Semipermeable membranes  

DOE Green Energy (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

170

Proteins  

NLE Websites -- All DOE Office Websites (Extended Search)

Bioscience: Bioenergy, Biosecurity, and Health » Bioscience: Bioenergy, Biosecurity, and Health » Proteins Protein Engineering, Structure, and Function Los Alamos scientists seek a comprehensive understanding of the structure and function of proteins which can lead to a multitude of possibilities, such as enhancing cellulose degradation for biofuels or creating new therapeutics. Get Expertise Cliff Unkefer Director, Protein Crystallography Station Email Tom Terwilliger Laboratory Fellow Email Andrew Bradbury Bioscience Group Leader Email Rebecca McDonald Bioscience Communications Email Los Alamos scientists are developing mosaic proteins that may one day become the first viable vaccine that can protect humans from HIV, the virus that causes AIDS. Scientists manipulate and mimic proteins for use in creating solutions for

171

Proteins  

NLE Websites -- All DOE Office Websites (Extended Search)

characteristics. Applications for GFP range from monitoring the expression level of a target protein to performing more effective drug discovery. Engineered (in collaboration...

172

Rhodobacter System for the Expression of Membrane  

Cell membranes are the interface between an organism and its environment. These biological structures contain proteins that are extremely important for many cellular ...

173

Zinc Uptake and Radial Transport in Roots of Arabidopsis thaliana: A Modelling Approach to Understand Accumulation  

E-Print Network (OSTI)

Zinc uptake in roots is believed to be mediated by ZIP (ZRT-, IRT- like Proteins) transporters. Once inside the symplast, zinc is transported to the pericycle, where it exits by means of HMA (Heavy Metal ATPase) transporters. The combination of symplastic transport and spatial separation of influx and efflux produces a pattern in which zinc accumulates in the pericycle. Here, mathematical modelling was employed to study the importance of ZIP regulation, HMA level and symplastic transport in creation of the radial pattern of zinc in primary roots of Arabidopsis thaliana. A comprehensive one-dimensional dynamical model of radial zinc transport in roots was developed and used to conduct simulations. The model accounts for the structure of the root consisting of symplast and apoplast and includes effects of water flow, diffusion, and cross-membrane transport via transporters. It also incorporates the radial geometry and varying porosity of root tissues, as well as regulation of ZIP transporters. Steady state patt...

Claus, Juliane; Chavarría-Krauser, Andrés

2012-01-01T23:59:59.000Z

174

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

175

Microporous Inorganic Membranes for Hydrogen Purification  

NLE Websites -- All DOE Office Websites (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

176

Membranes – Phosphazene  

INL’s new phosphazene membrane technology provides a method for making polydichlorophosphazene using solid state reactants that simplifies previous processes with a “single pot” two-step process. The process eliminates use of chlorinated hydrocarbon ...

177

Deciphering the Mechanism of E. coli tat Protien Transport: Kinetic Substeps and Cargo Properties  

E-Print Network (OSTI)

The Escherichia coli twin-arginine translocation (Tat) system transports fully folded and assembled proteins across the inner membrane into the periplasmic space. The E. coli Tat machinery minimally consists of three integral membrane proteins: TatA, TatB and TatC. A popular model of Tat translocation is that cargo first interacts with a substrate binding complex composed of TatB and TatC and then is transported across the inner membrane through a channel comprised primarily of TatA. The most common method for observing the kinetics of Tat transport, a protease protection assay, lacks the ability to distinguish between individual transport sub-steps and is limited by the inability to observe translocation in real-time. Therefore, a real-time FRET based assay was developed to observe interactions between the cargo protein pre-SufI, and its initial binding site, the TatBC complex. The cargo was found to first associate with the TatBC complex, and then, in the presence of a membrane potential (?psi), migrate away from the initial binding site after a 20-45 second delay. Since cargo migration away from the TatBC complex was not directly promoted by the presence of a ?psi, the delay likely represents some preparatory step that results in a transport competent translocon. In addition, the Tat system has long been identified as a potential biotechnological tool for protein production. However, much is still unknown about which cargos are suitable for transport by the Tat system. To probe the Tat system’s ability to transport substrates of different sizes and shapes, 18 different cargos were generated using the natural Tat substrate pre-SufI as a base. Transport efficiencies for these cargos indicate that not only is the Tat machinery’s ability to transport substrates determined by the protein’s molecular weight, as well as by its dimensions. In total, these results suggest a dynamic translocon that undergoes functionally significant, ?psi-dependent changes during translocation. Moreover, not every protein cargo can be directed through the Tat translocon by a Tat signal peptide, and this selectivity is not only related to the overall size of the protein, but also dependent on shape.

Whitaker, Neal 1982-

2012-12-01T23:59:59.000Z

178

Ceramic Membranes for Hydrogen/Oxygen Production - Energy ...  

Ceramic Membranes Developed at Argonne May Bring Fuel-Cell Cars Closer to Reality ... pure hydrogen for transportation and power applications from fossil fuels.

179

Water transport properties of fuel cell ionomers  

DOE Green Energy (OSTI)

We will report transport parameters measured for several available perfluorosulfonate membranes. The water sorption characteristics, diffusion coefficient of water, electroosmotic drag, and conductivity will be compared for these materials. The intrinsic properties of the membranes will be the basis of our comparison. An objective look at transport parameters should enable us to compare membranes without the skewing effects of extensive features such as membrane thickness. 8 refs., 4 figs., 2 tabs.

Zawodzinski, T.A. Jr.; Springer, T.E.; Davey, J.; Valerio, J.; Gottesfeld, S.

1991-01-01T23:59:59.000Z

180

Biomolecular transport and separation in nanotubular networks.  

Science Conference Proceedings (OSTI)

Cell membranes are dynamic substrates that achieve a diverse array of functions through multi-scale reconfigurations. We explore the morphological changes that occur upon protein interaction to model membrane systems that induce deformation of their planar structure to yield nanotube assemblies. In the two examples shown in this report we will describe the use of membrane adhesion and particle trajectory to form lipid nanotubes via mechanical stretching, and protein adsorption onto domains and the induction of membrane curvature through steric pressure. Through this work the relationship between membrane bending rigidity, protein affinity, and line tension of phase separated structures were examined and their relationship in biological membranes explored.

Stachowiak, Jeanne C.; Stevens, Mark Jackson (Sandia National Laboratories, Albuquerque, NM); Robinson, David B.; Branda, Steven S.; Zendejas, Frank; Meagher, Robert J.; Sasaki, Darryl Yoshio; Bachand, George David (Sandia National Laboratories, Albuquerque, NM); Hayden, Carl C.; Sinha, Anupama; Abate, Elisa; Wang, Julia; Carroll-Portillo, Amanda (Sandia National Laboratories, Albuquerque, NM); Liu, Haiqing (Sandia National Laboratories, Albuquerque, NM)

2010-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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.


181

Direct-hydrogen-fueled proton-exchange-membrane (PEM) fuel cell system for transportation applications. Quarterly technical progress report Number 1, July 1--September 30, 1994  

DOE Green Energy (OSTI)

This is the first Technical Progress Report for DOE Contract No. DE-AC02-94CE50389 awarded to Ford Motor Company on July 1, 1994. The overall objective of this contract is to advance the Proton-Exchange-Membrane (PEM) fuel cell technology for automotive applications. Specifically, the objectives resulting from this contract are to: (1) develop and demonstrate on a laboratory propulsion system within 2-1/2 years a fully functional PEM Fuel Cell Power System (including fuel cell peripherals, peak power augmentation and controls), this propulsion system will achieve, or will be shown to have the growth potential to achieve, the weights, volumes, and production costs which are competitive with those same attributes of equivalently performing internal combustion engine propulsion systems; (2) select and demonstrate a baseline onboard hydrogen storage method with acceptable weight, volume, cost, and safety features and analyze future alternatives; (3) analyze the hydrogen infrastructure components to ensure that hydrogen can be safely supplied to vehicles at geographically widespread convenient sites and at prices which are less than current gasoline prices per vehicle-mile; (4) identify any future R and D needs for a fully integrated vehicle and for achieving the system cost and performance goals.

Oei, G.

1994-11-04T23:59:59.000Z

182

Direct-hydrogen-fueled proton-exchange-membrane (PEM) fuel cell system for transportation applications. Quarterly technical progress report No. 4, April 1, 1995--June 30, 1995  

Science Conference Proceedings (OSTI)

This is the fourth Technical Progress Report for DOE Contract No. DE-AC02-94CE50389 awarded to Ford Motor Company on July 1, 1994. The overall objective of this contract is to advance the Proton-Exchange-Membrane (PEM) fuel cell technology for automotive applications. Specifically, the objectives resulting from this contract are to: (1) Develop and demonstrate on a laboratory propulsion system within 2-1/2 years a fully functional PEM Fuel Cell Power System (including fuel cell peripherals, peak power augmentation and controls). This propulsion system will achieve, or will be shown to have the growth potential to achieve, the weights, volumes, and production costs which are competitive with those same attributes of equivalently performing internal combustion engine propulsion systems; (2) Select and demonstrate a baseline onboard hydrogen storage method with acceptable weight, volume, cost, and safety features and analyze future alternatives; and (3) Analyze the hydrogen infrastructure components to ensure that hydrogen can be safely supplied to vehicles at geographically widespread convenient sites and at prices which are less than current gasoline prices per vehicle-mile; (4) Identify any future R&D needs for a fully integrated vehicle and for achieving the system cost and performance goals.

Oei, D.

1995-08-03T23:59:59.000Z

183

Sweeping Gas Membrane Desalination Using Commercial Hydrophobic Hollow Fiber Membranes  

Science Conference Proceedings (OSTI)

Water shortages affect 88 developing countries that are home to half of the world's population. In these places, 80-90% of all diseases and 30% of all deaths result from poor water quality. Furthermore, over the next 25 years, the number of people affected by severe water shortages is expected to increase fourfold. Low cost methods of purifying freshwater, and desalting seawater are required to contend with this destabilizing trend. Membrane distillation (MD) is an emerging technology for separations that are traditionally accomplished via conventional distillation or reverse osmosis. As applied to desalination, MD involves the transport of water vapor from a saline solution through the pores of a hydrophobic membrane. In sweeping gas MD, a flowing gas stream is used to flush the water vapor from the permeate side of the membrane, thereby maintaining the vapor pressure gradient necessary for mass transfer. Since liquid does not penetrate the hydrophobic membrane, dissolved ions are completely rejected by the membrane. MD has a number of potential advantages over conventional desalination including low temperature and pressure operation, reduced membrane strength requirements, compact size, and 100% rejection of non-volatiles. The present work evaluated the suitability of commercially available technology for sweeping gas membrane desalination. Evaluations were conducted with Celgard Liqui-Cel{reg_sign} Extra-Flow 2.5X8 membrane contactors with X-30 and X-40 hydrophobic hollow fiber membranes. Our results show that sweeping gas membrane desalination systems are capable of producing low total dissolved solids (TDS) water, typically 10 ppm or less, from seawater, using low grade heat. However, there are several barriers that currently prevent sweeping gas MD from being a viable desalination technology. The primary problem is that large air flows are required to achieve significant water yields, and the costs associated with transporting this air are prohibitive. To overcome this barrier, at least two improvements are required. First, new and different contactor geometries are necessary to achieve efficient contact with an extremely low pressure drop. Second, the temperature limits of the membranes must be increased. In the absence of these improvements, sweeping gas MD will not be economically competitive. However, the membranes may still find use in hybrid desalination systems.

EVANS, LINDSEY; MILLER, JAMES E.

2002-01-01T23:59:59.000Z

184

Amphiphiles for protein solubilization and stabilization  

DOE Patents (OSTI)

The invention provides amphiphiles for manipulating membrane proteins. The amphiphiles can feature carbohydrate-derived hydrophilic groups and branchpoints in the hydrophilic moiety and/or in a lipophilic moiety. Such amphiphiles are useful as detergents for solubilization and stabilization of membrane proteins, including photosynthetic protein superassemblies obtained from bacterial membranes.

Gellman, Samuel Helmer; Chae, Pil Seok; Laible, Philip D.; Wander, Marc J.

2012-09-11T23:59:59.000Z

185

Proton Exchange Membranes for Fuel Cells  

Science Conference Proceedings (OSTI)

Proton exchange membrane, also known as polymer electrolyte membrane, fuel cells (PEMFCs) offer the promise of efficient conversion of chemical energy of fuel, such as hydrogen or methanol, into electricity with minimal pollution. Their widespread use to power zero-emission automobiles as part of a hydrogen economy can contribute to enhanced energy security and reduction in greenhouse gas emissions. However, the commercial viability of PEMFC technology is hindered by high cost associated with the membrane electrode assembly (MEA) and poor membrane durability under prolonged operation at elevated temperature. Membranes for automotive fuel cell applications need to perform well over a period comparable to the life of an automotive engine and under heavy load cycling including start-stop cycling under sub-freezing conditions. The combination of elevated temperature, changes in humidity levels, physical stresses and harsh chemical environment contribute to membrane degradation. Perfluorinated sulfonic acid (PFSA)-based membranes, such as Nafion®, have been the mainstay of PEMFC technology. Their limitations, in terms of cost and poor conductivity at low hydration, have led to continuing research into membranes that have good proton conductivity at elevated temperatures above 120 °C and under low humidity conditions. Such membranes have the potential to avoid catalyst poisoning, simplify fuel cell design and reduce the cost of fuel cells. Hydrocarbon-based membranes are being developed as alternatives to PFSA membranes, but concerns about chemical and mechanical stability and durability remain. Novel anhydrous membranes based on polymer gels infused with protic ionic liquids have also been recently proposed, but considerable fundamental research is needed to understand proton transport in novel membranes and evaluate durability under fuel cell operating conditions. In order to advance this promising technology, it is essential to rationally design the next generation of PEMs based on an understanding of chemistry, membrane morphology and proton transport obtained from experiment, theory and computer simulation.

Devanathan, Ramaswami

2010-11-01T23:59:59.000Z

186

Hybrid Membranes for Light Gas Separations  

E-Print Network (OSTI)

Membrane separations provide a potentially attractive technology over conventional processes due to their advantages, such as low capital cost and energy consumption. The goal of this thesis is to design hybrid membranes that facilitate specific gas separations, especially olefin/paraffin separations. This thesis focuses on the designing dendrimer-based hybrid membranes on mesoporous alumina for reverse-selective separations, synthesizing Cu(I)-dendrimer hybrid membrane to facilitate olefin/paraffin separations, particularly ethylene/methane separation, and investigating the influence of solvent, stabilizing ligands on facilitated transport membrane. Reverse-selective gas separations have attracted considerable attention in removing the heavier/larger molecules from gas mixtures. In this study, dendrimer-based chemistry was proved to be an effective method by altering dendrimer structures and generations. G6-PIP, G4-AMP and G3-XDA are capable to fill the alumina mesopores and slight selectivity are observed. Facilitated transport membranes were made to increase the olefin/paraffin selectivity based on their chemical interaction with olefin molecules. Two approaches were explored, the first was to combine facilitator Cu(I) with dendrimer hybrid membrane to increase olefin permeance and olefin/paraffin selectivity simultaneously, and second was to facilitate transport membrane functionality by altering solvents and stabilizing ligands. Promising results were found by these two approaches, which were: 1) olefin/paraffin selectivity slightly increased by introducing facilitator Cu(I), 2) the interaction between Cu(I) and dendrimer functional groups are better known.

Liu, Ting

2012-05-01T23:59:59.000Z

187

Ionically Conducting Membranes for Hydrogen Production and Separation  

NLE Websites -- All DOE Office Websites (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

188

The influence of oscillating electromagnetic fields on membrane structure and function: Synthetic liposome and natural membrane bilayer systems with direct application to the controlled delivery of chemical agents  

Science Conference Proceedings (OSTI)

Investigations have been conducted to determine if an imposed electromagnetic field can influence membrane transport, and ion and drug permeability in both synthetic and natural cell membrane systems. Microwave fields enhance accumulation of sodium in the lymphocyte and induce protein shedding at Tc. Microwaves also trigger membrane permeability of liposome systems under specific field exposure conditions. Sensitivity varies in a defined way in bilayers displaying a membrane structural phase transition temperature, Tc; maximal release was observed at or near Tc. Significantly, liposome systems without a membrane phase transition were also found to experience permeability increases but, in contrast, this response was temperature independent. The above results indicate that field-enhanced drug release occurs in liposome vesicles that possess a Tc as well as non-Tc liposomes. Additional studies extend non-Tc liposome responses to the in vivo case in which microwaves trigger Gentamicin release from a liposome depot'' placed subcutaneously in the rat hind leg. In addition, evidence is provided that cell surface sequestered liposomes can be triggered by microwave fields to release drugs directly into target cells. 24 refs., 6 figs.

Liburdy, R.P.; de Manincor, D.; Fingado, B.

1989-09-01T23:59:59.000Z

189

Gas phase fractionation method using porous ceramic membrane  

DOE Patents (OSTI)

Flaw-free porous ceramic membranes fabricated from metal sols and coated onto a porous support are advantageously used in gas phase fractionation methods. Mean pore diameters of less than 40 .ANG., preferably 5-20 .ANG. and most preferably about 15 .ANG., are permeable at lower pressures than existing membranes. Condensation of gases in small pores and non-Knudsen membrane transport mechanisms are employed to facilitate and increase membrane permeability and permselectivity.

Peterson, Reid A. (Madison, WI); Hill, Jr., Charles G. (Madison, WI); Anderson, Marc A. (Madison, WI)

1996-01-01T23:59:59.000Z

190

W48F/F200T double mutant, we started from the equil-ibrated model of the native protein in the membrane.  

E-Print Network (OSTI)

survival and proliferation in mammals by inhibiting the activity of members of the FOXO family phosphoinositide 3-kinase to the protein kinase Akt controls organismal life-span in invertebrates and cell's effects on DNA repair. These findings indicate that in mammals FOXO3a regulates the resistance of cells

Datta, Sandeep Robert

191

Hindered transport in composite hydrogels  

E-Print Network (OSTI)

The ultimate goal of this research was to develop a greater understanding of the structural components needed to describe transport within the glomerular basement membrane (GBM). Specifically, dimensionless diffusive and ...

Kosto, Kimberly Bryan, 1977-

2004-01-01T23:59:59.000Z

192

Computational and experimental platform for understanding and optimizing water flux and salt rejection in nanoporous membranes.  

Science Conference Proceedings (OSTI)

Affordable clean water is both a global and a national security issue as lack of it can cause death, disease, and international tension. Furthermore, efficient water filtration reduces the demand for energy, another national issue. The best current solution to clean water lies in reverse osmosis (RO) membranes that remove salts from water with applied pressure, but widely used polymeric membrane technology is energy intensive and produces water depleted in useful electrolytes. Furthermore incremental improvements, based on engineering solutions rather than new materials, have yielded only modest gains in performance over the last 25 years. We have pursued a creative and innovative new approach to membrane design and development for cheap desalination membranes by approaching the problem at the molecular level of pore design. Our inspiration comes from natural biological channels, which permit faster water transport than current reverse osmosis membranes and selectively pass healthy ions. Aiming for an order-of-magnitude improvement over mature polymer technology carries significant inherent risks. The success of our fundamental research effort lies in our exploiting, extending, and integrating recent advances by our team in theory, modeling, nano-fabrication and platform development. A combined theoretical and experimental platform has been developed to understand the interplay between water flux and ion rejection in precisely-defined nano-channels. Our innovative functionalization of solid state nanoporous membranes with organic protein-mimetic polymers achieves 3-fold improvement in water flux over commercial RO membranes and has yielded a pending patent and industrial interest. Our success has generated useful contributions to energy storage, nanoscience, and membrane technology research and development important for national health and prosperity.

Rempe, Susan B.

2010-09-01T23:59:59.000Z

193

Reaction-Driven Ion Transport Membrane  

NLE Websites -- All DOE Office Websites (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.

194

Scale-Up of Hydrogen Transport Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

feedstocks, such as coal, are converted into gaseous components, called synthesis gas (syngas), a mixture of hydrogen (H 2 ) and carbon monoxide (CO). The syngas can be further...

195

The axonal membrane protein Caspr, a homologue of neurexin IV, is a component of the septate-like paranodal junctions that assemble during myelination  

E-Print Network (OSTI)

Abstract. We have investigated the potential role of contactin and contactin-associated protein (Caspr) in the axonal–glial interactions of myelination. In the nervous system, contactin is expressed by neurons, oligodendrocytes, and their progenitors, but not by Schwann cells. Expression of Caspr, a homologue of Neurexin IV, is restricted to neurons. Both contactin and Caspr are uniformly expressed at high levels on the surface of unensheathed neurites and are downregulated during myelination in vitro and in vivo. Contactin is downregulated along the entire myelinated nerve fiber. In contrast, Caspr expression initially remains elevated along segments of neurites associated with nascent myelin sheaths. With further maturation, Caspr is downregulated in the internode and becomes strikingly concentrated

Steven Einheber; George Zanazzi; William Ching; Steven Scherer; Teresa A. Milner; Elior Peles; James L. Salzer

1997-01-01T23:59:59.000Z

196

Characterization & Transport in Nanoporous Networks  

DOE Green Energy (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

197

Fission of a multiphase membrane tube  

E-Print Network (OSTI)

A common mechanism for intracellular transport is the use of controlled deformations of the membrane to create spherical or tubular buds. While the basic physical properties of homogeneous membranes are relatively well-known, the effects of inhomogeneities within membranes are very much an active field of study. Membrane domains enriched in certain lipids in particular are attracting much attention, and in this Letter we investigate the effect of such domains on the shape and fate of membrane tubes. Recent experiments have demonstrated that forced lipid phase separation can trigger tube fission, and we demonstrate how this can be understood purely from the difference in elastic constants between the domains. Moreover, the proposed model predicts timescales for fission that agree well with experimental findings.

Jean-Marc Allain; Cornelis Storm; Aurelien Roux; Martine Ben Amar; Jean-Francois Joanny

2004-04-19T23:59:59.000Z

198

Proton conducting ceramic membranes for hydrogen separation  

Science Conference Proceedings (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

199

Structure of ABC Transporter MsbA in Complex with ATP Vi and  

NLE Websites -- All DOE Office Websites (Extended Search)

ABC Transporter MsbA ABC Transporter MsbA in Comlex with ATP Vi and Lipopolysaccharide: Implications for Lipid Flipping Christopher L. Reyes and Geoffrey Chang* Department of Molecular Biology, The Scripps Research Institute, 10550 N. Torrey Pines Rd. CB105, La Jolla, CA 92137 ATP-binding cassette (ABC) transporters are integral membrane proteins critical for the transport of a wide variety of substrate molecules across the cell membrane. MsbA, along with human MDR1 P-glycoprotein, are members of the ABC transporter family that have been implicated in multidrug resistance by coupling ATP binding and hydrolysis to substrate transport. This drug efflux results in resistance to antibiotics in microorganisms and resistance to chemotherapeutic drugs in human cancer cells1. Using x-ray diffraction data collected at SSRL Beam Line 11-1 and ALS, we have determined the 4.2 Ã… x-ray crystal structure of MsbA in complex with transition state mimic ADP, vanadate (an analog of the g phosphate of ATP) and the human immunomodulatory substrate Ra lipopolysaccharide. This structure is the first intact ABC transporter in complex with nucleotide and substrate.

200

Composite sensor membrane  

DOE Patents (OSTI)

A sensor may include a membrane to deflect in response to a change in surface stress, where a layer on the membrane is to couple one or more probe molecules with the membrane. The membrane may deflect when a target molecule reacts with one or more probe molecules.

Majumdar, Arun (Orinda, CA); Satyanarayana, Srinath (Berkeley, CA); Yue, Min (Albany, CA)

2008-03-18T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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

Function of proteins  

NLE Websites -- All DOE Office Websites (Extended Search)

Function of proteins Function of proteins Name: Collins Location: N/A Country: N/A Date: N/A Question: What is the function of proteins in your body? Replies: Proteins have many functions. They serve as enzymatic catalysts, are used as transport molecules (hemoglobin transports oxygen) and storage molecules (iron is stored in the liver as a complex with the protein ferritin); they are used in movement (proteins are the major component of muscles); they are needed for mechanical support (skin and bone contain collagen-a fibrous protein); they mediate cell responses (rhodopsin is a protein in the eye which is used for vision); antibody proteins are needed for immune protection; control of growth and cell differentiation uses proteins (hormones). These are just a few examples of the many, many functions of proteins.

202

Transepithelial transport in cell culture: Stoichiometry of Na/phlorizin ...  

Science Conference Proceedings (OSTI)

Membrane Biology. Transepithelial Transport in Cell Culture: Stoiehiometry of Na /Phlorizin Binding and Na/D-Glueose Cotransport. A Two-Step, Two-Sodium ...

203

Supported Ionic Liquid Membranes for Gas Separation  

SciTech Connect

Ionic liquids have been rapidly gaining attention for various applications including solvent separation and gas capture. These substances are noted for extremely low vapor pressure and high CO2 solubility making them ideal as transport or capture media for CO2 abatement in power generation applications. Ionic liquids, combined with various supports to form membranes, have been proven selective in CO2 separation. Several ionic liquids and a variety of polymer supports have been studied over a temperature range from 37°C to 300°C and have been optimized for stability. The membranes have demonstrated high permeability and high selectivity since the supported ionic liquid membranes incorporate functionality capable of chemically complexing CO2. A study aimed at improving supported ionic liquid membranes will examine their durability with greater transmembrane pressures and the effects on CO2 permeance, CO2/H2 selectivity and thermal stability.

Myers, C.R.; Ilconich, J.B.; Pennline, H.W.; Luebke, D.R.

2007-08-01T23:59:59.000Z

204

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

205

Supported inorganic membranes  

DOE Patents (OSTI)

Supported inorganic membranes capable of molecular sieving, and methods for their production, are provided. The subject membranes exhibit high flux and high selectivity. The subject membranes are substantially defect free and less than about 100 nm thick. The pores of the subject membranes have an average critical pore radius of less than about 5 .ANG., and have a narrow pore size distribution. The subject membranes are prepared by coating a porous substrate with a polymeric sol, preferably under conditions of low relative pressure of the liquid constituents of the sol. The coated substrate is dried and calcined to produce the subject supported membrane. Also provided are methods of derivatizing the surface of supported inorganic membranes with metal alkoxides. The subject membranes find use in a variety of applications, such as the separation of constituents of gaseous streams, as catalysts and catalyst supports, and the like.

Sehgal, Rakesh (Albuquerque, NM); Brinker, Charles Jeffrey (Albuquerque, NM)

1998-01-01T23:59:59.000Z

206

Sustainable Transport  

E-Print Network (OSTI)

THOUGHT PIECE Sustainable Transport by Melvin M. Webberwant to sustain any mode of transport only if we judge it todraconian in rejecting transport modes that have failed in

Webber, Melvin

2006-01-01T23:59:59.000Z

207

DOE Science Showcase - Understanding Protein Membranes | OSTI...  

Office of Scientific and Technical Information (OSTI)

to RSS OSTI Blog Get Widgets Get Alert Services OSTI Facebook OSTI Twitter OSTI Google+ Bookmark and Share (Link will open in a new window) Go to Videos Loading... Stop news...

208

Composite fuel cell membranes  

DOE Patents (OSTI)

A bilayer or trilayer composite ion exchange membrane is described suitable for use in a fuel cell. The composite membrane has a high equivalent weight thick layer in order to provide sufficient strength and low equivalent weight surface layers for improved electrical performance in a fuel cell. In use, the composite membrane is provided with electrode surface layers. The composite membrane can be composed of a sulfonic fluoropolymer in both core and surface layers.

Plowman, K.R.; Rehg, T.J.; Davis, L.W.; Carl, W.P.; Cisar, A.J.; Eastland, C.S.

1997-08-05T23:59:59.000Z

209

Cadmium sulfide membranes  

DOE Patents (OSTI)

A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

Spanhel, Lubomir (Madison, WI); Anderson, Marc A. (Madison, WI)

1992-07-07T23:59:59.000Z

210

Cadmium sulfide membranes  

DOE Patents (OSTI)

A method is described for the creation of novel q-effect cadmium sulfide membranes. The membranes are made by first creating a dilute cadmium sulfide colloid in aqueous suspension and then removing the water and excess salts therefrom. The cadmium sulfide membrane thus produced is luminescent at room temperature and may have application in laser fabrication.

Spanhel, Lubomir (Madison, WI); Anderson, Marc A. (Madison, WI)

1991-10-22T23:59:59.000Z

211

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

212

Critical Casimir forces in cellular membranes  

E-Print Network (OSTI)

Recent experiments suggest that membranes of living cells are tuned close to a miscibility critical point in the 2D Ising universality class. We propose that one role for this proximity to criticality in live cells is to provide a conduit for relatively long-ranged critical Casimir forces. Using techniques from conformal field theory we calculate potentials of mean force between membrane bound inclusions mediated by their local interactions with the composition order parameter. We verify these calculations using Monte-Carlo where we also compare critical and off-critical results. Our findings suggest that membrane bound proteins experience weak yet long range forces mediated by critical composition fluctuations in the plasma membranes of living cells.

Benjamin B. Machta; Sarah L. Veatch; James P. Sethna

2012-03-09T23:59:59.000Z

213

International Symposium on Defects, Transport and Related ...  

Science Conference Proceedings (OSTI)

Structure, including point and other defects in crystalline ceramic and ... Compositional Stability and Oxygen Exchange Kinetics of Oxide Hetero-Junction Electrodes ... Secondary Transport Phenomena in Ceramic Membranes under ...

214

Fuel Cell Technologies Office: High Temperature Membrane Working Group  

NLE Websites -- All DOE Office Websites (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.

215

Argonne CNM News: Thinnest Nanofiltration Membrane to Date  

NLE Websites -- All DOE Office Websites (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

216

BASELINE MEMBRANE SELECTION AND CHARACTERIZATION FOR AN SDE  

DOE Green Energy (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

217

Supported liquid membrane system  

DOE Patents (OSTI)

A cell apparatus for a supported liquid membrane including opposing faceplates, each having a spirally configured groove, an inlet groove at a first end of the spirally configured groove, and an outlet groove at the other end of the spirally configured groove, within the opposing faces of the faceplates, a microporous membrane situated between the grooved faces of the faceplates, said microporous membrane containing an extractant mixture selective for a predetermined chemical species within the pores of said membrane, means for aligning the grooves of the faceplates in an directly opposing configuration with the porous membrane being situated therebetween, such that the aligned grooves form a pair of directly opposing channels, separate feed solution and stripping solution compartments connected to respective channels between the faceplates and the membrane, separate pumping means for passing feed solution and stripping solution through the channels is provided.

Takigawa, D.Y.; Bush, H. Jr.

1990-12-31T23:59:59.000Z

218

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

219

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

220

Crystal Structure of the EmrE Multidrug Transporter with a Substrate  

NLE Websites -- All DOE Office Websites (Extended Search)

the EmrE the EmrE Multidrug Transporter with a Substrate O. Pornillos, Y-J. Chen, A. P. Chen and G. Chang Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037 View of the EmrE homodimer. The N and C termini of the two subunits are colored. The bound substrate (TPP) is shown in green. The glutamine 14 which is implicated in the proton-depended drug translocation is shown in yellow. A major obstacle to effective treatment of bacterial infections is the emergence of drug-resistant strains. Multidrug resistance arises, in part, through the action of integral membrane proteins called multidrug transporters. Multidrug resistance transporters threaten to reverse the progress in treating infectious disease by extruding a wide range of drug

Note: This page contains sample records for the topic "membrane transport proteins" 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

Siloxane-grafted membranes  

DOE Patents (OSTI)

Composite cellulosic semipermeable membranes are disclosed which are the covalently bonded reaction product of an asymmetric cellulosic semipermeable membrane and a polysiloxane containing reactive functional group. The two reactants chemically bond by ether, ester, amide or acrylate linkages to form a siloxane-grafted cellulosic membrane having superior selectivity and flux stability. Selectivity may be enhanced by wetting the surface with a swelling agent such as water.

Friesen, D.T.; Obligin, A.S.

1989-10-31T23:59:59.000Z

222

Membranes for Clean Water  

Science Conference Proceedings (OSTI)

Membranes for Clean Water. Summary: ... Description: Impact. Access to affordable, clean water is vital to the nation's economic growth and security. ...

2013-02-02T23:59:59.000Z

223

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

224

Microporous alumina ceramic membranes  

DOE Patents (OSTI)

Several methods are disclosed for the preparation microporous alumina ceramic membranes. For the first time, porous alumina membranes are made which have mean pore sizes less than 100 Angstroms and substantially no pores larger than that size. The methods are based on improved sol-gel techniques.

Anderson, Marc A. (Madison, WI); Sheng, Guangyao (Madison, WI)

1993-01-01T23:59:59.000Z

225

Membrane module assembly  

DOE Patents (OSTI)

A membrane module assembly is described which is adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation. 2 figures.

Kaschemekat, J.

1994-03-15T23:59:59.000Z

226

Microporous alumina ceramic membranes  

DOE Patents (OSTI)

Several methods are disclosed for the preparation microporous alumina ceramic membranes. For the first time, porous alumina membranes are made which have mean pore sizes less than 100 Angstroms and substantially no pores larger than that size. The methods are based on improved sol-gel techniques.

Anderson, M.A.; Guangyao Sheng.

1993-05-04T23:59:59.000Z

227

Documents: Transportation  

NLE Websites -- All DOE Office Websites (Extended Search)

Search Documents: Search PDF Documents View a list of all documents Transportation PDF Icon Transportation Impact Assessment for Shipment of Uranium Hexafluoride (UF6) Cylinders...

228

Membranes with a boundary  

E-Print Network (OSTI)

We investigate the recently developed theory of multiple membranes. In particular, we consider open membranes, i.e. the theory defined on a membrane world volume with a boundary. We first restrict our attention to the gauge sector of the theory. We obtain a boundary action from the Chern-Simons terms. Secondly, we consider the addition of certain boundary terms to various Chern-Simons theories coupled to matter. These terms ensure the full bulk plus boundary action has the correct amount of supersymmetry. For the ABJM model, this construction motivates the inclusion of a boundary quartic scalar potential. The boundary dynamics obtained from our modified theory produce Basu-Harvey type equations describing membranes ending on a fivebrane. The ultimate goal of this work is to throw light on the theory of fivebranes using the theory of open membranes.

David S Berman; Daniel C Thompson

2009-04-01T23:59:59.000Z

229

EVALUATION OF PROTON-CONDUCTING MEMBRANES FOR USE IN A SULFUR-DIOXIDE DEPOLARIZED ELECTROLYZER  

DOE Green Energy (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

230

Novel, Ceramic Membrane System For Hydrogen Separation  

Science Conference Proceedings (OSTI)

Separation of hydrogen from coal gas represents one of the most promising ways to produce alternative sources of fuel. Ceramatec, teamed with CoorsTek and Sandia National Laboratories has developed materials technology for a pressure driven, high temperature proton-electron mixed conducting membrane system to remove hydrogen from the syngas. This system separates high purity hydrogen and isolates high pressure CO{sub 2} as the retentate, which is amenable to low cost capture and transport to storage sites. The team demonstrated a highly efficient, pressure-driven hydrogen separation membrane to generate high purity hydrogen from syngas using a novel ceramic-ceramic composite membrane. Recognizing the benefits and limitations of present membrane systems, the all-ceramic system has been developed to address the key technical challenges related to materials performance under actual operating conditions, while retaining the advantages of thermal and process compatibility offered by the ceramic membranes. The feasibility of the concept has already been demonstrated at Ceramatec. This project developed advanced materials composition for potential integration with water gas shift rectors to maximize the hydrogenproduction.

Elangovan, S.

2012-12-31T23:59:59.000Z

231

Biominetic Membrane for Co2 Capture from Flue Gas  

NLE Websites -- All DOE Office Websites (Extended Search)

Biomimetic Membrane for CO Biomimetic Membrane for CO 2 Capture from Flue Gas Background Carbon Capture and Sequestration (CCS) is a three-step process including capture, pipeline transport, and geologic storage of which the capture of carbon dioxide (CO 2 ) is the most costly and technically challenging. Current available methods impose significant energy burdens that severely impact their overall effectiveness as a significant deployment option. Of the available capture technologies for post

232

DOE Hydrogen Analysis Repository: Cost Analysis of Proton Exchange Membrane  

NLE Websites -- All DOE Office Websites (Extended Search)

Cost Analysis of Proton Exchange Membrane Fuel Cell Systems for Cost Analysis of Proton Exchange Membrane Fuel Cell Systems for Transportation Project Summary Full Title: Cost Analysis of Proton Exchange Membrane (PEM) Fuel Cell Systems for Transportation Project ID: 196 Principal Investigator: Eric Carlson Keywords: Fuel cells, fuel cell vehicles (FCV), transportation, costs Purpose Assess the cost of an 80 kW direct hydrogen fuel cell system relative to the DOE 2005 target of $125/kW. The system includes the fuel cell stack and balance-of-plant (BOP) components for water, thermal, and fuel management, but not hydrogen storage. Performer Principal Investigator: Eric Carlson Organization: TIAX, LLC Address: 15 Acorn Park Cambridge, MA 02140-2328 Telephone: 617-498-5903 Email: carlson.e@tiaxllc.com Additional Performers: P. Kopf, TIAX, LLC; J. Sinha, TIAX, LLC; S. Sriramulu, TIAX, LLC

233

Biomimetric Membrane for CO2 Capture from Flue Gas  

NLE Websites -- All DOE Office Websites (Extended Search)

Biomimetic memBrane for co Biomimetic memBrane for co 2 capture from flue Gas Background Carbon Capture and Sequestration (CCS) is a three-step process including capture, pipeline transport and geologic storage of which the capture of carbon dioxide (CO 2 ) is the most costly and technically challenging. Current available methods impose significant energy burdens that severely impact their overall effectiveness as a significant deployment option. Of the available capture technologies for post combustion applications - absorption, adsorption, reaction and membranes chemically facilitated absorption promises to be the most cost-effective membrane solution for post combustion application. The Carbozyme technology extracts CO 2 from low concentration, low pressure sources by means of chemical facilitation of a polymer membrane. The chemical

234

The Stirred Tank Reactor Polymer Electrolyte Membrane Fuel Cell  

E-Print Network (OSTI)

The design and operation of a differential Polymer Electrolyte Membrane (PEM) fuel cell is described. The fuel cell design is based on coupled Stirred Tank Reactors (STR); the gas phase in each reactor compartment was well mixed. The characteristic times for reactant flow, gas phase diffusion and reaction were chosen so that the gas compositions at both the anode and cathode are uniform. The STR PEM fuel cell is one-dimensional; the only spatial gradients are transverse to the membrane. The STR PEM fuel cell was employed to examine fuel cell start- up, and its dynamic responses to changes in load, temperature and reactant flow rates. Multiple time scales in systems response are found to correspond to water absorption by the membrane, water transport through the membrane and stress-related mechanical changes of the membrane.

Benziger, J; Karnas, E; Moxley, J; Teuscher, C; Kevrekidis, Yu G; Benziger, Jay

2003-01-01T23:59:59.000Z

235

Novel membrane technology for green ethylene production.  

Science Conference Proceedings (OSTI)

Ethylene is currently produced by pyrolysis of ethane in the presence of steam. This reaction requires substantial energy input, and the equilibrium conversion is thermodynamically limited. The reaction also produces significant amounts of greenhouse gases (CO and CO{sub 2}) because of the direct contact between carbon and steam. Argonne has demonstrated a new way to make ethylene via ethane dehydrogenation using a dense hydrogen transport membrane (HTM) to drive the unfavorable equilibrium conversion. Preliminary experiments show that the new approach can produce ethylene yields well above existing pyrolysis technology and also significantly above the thermodynamic equilibrium limit, while completely eliminating the production of greenhouse gases. With Argonne's approach, a disk-type dense ceramic/metal composite (cermet) membrane is used to produce ethylene by dehydrogenation of ethane at 850 C. The gas-transport membrane reactor combines a reversible chemical reaction with selective separation of one product species and leads to increased reactant conversion to the desired product. In an experiment ethane was passed over one side of the HTM membrane and air over the other side. The hydrogen produced by the dehydrogenation of ethane was removed and transported through the HTM to the air side. The air provided the driving force required for the transport of hydrogen through the HTM. The reaction between transported hydrogen and oxygen in air can provide the energy needed for the dehydrogenation reaction. At 850 C and 1-atm pressure, equilibrium conversion of ethane normally limits the ethylene yield to 64%, but Argonne has shown that an ethylene yield of 69% with a selectivity of 88% can be obtained under the same conditions. Coking was not a problem in runs extending over several weeks. Further improved HTM materials will lower the temperature required for high conversion at a reasonable residence time, while the lower temperature will suppress unwanted side reactions and prolong membrane life. With the Argonne approach, oxygen does not contact the ethane/ethylene stream, so oxidation products are not formed. Consequently, higher selectivity to ethylene and fewer by-products can be achieved. Some benefits are: (1) Simplifies overall product purification and processing schemes; (2) Results in greater energy efficiency; (3) Completely eliminates greenhouse gases from the reactor section; and (4) Lowers the cost of the 'back end' purification train, which accounts for about 70% of the capital cost of a conventional ethylene production unit.

Balachandran, U.; Lee, T. H.; Dorris, S. E.; Udovich, C. A.; Scouten, C. G.; Marshall, C. L. (Energy Systems); ( CSE)

2008-01-01T23:59:59.000Z

236

A Nascent Membrane Protein Is Located Adjacent to ER Membrane Proteins Throughout Its Integration and Translation  

E-Print Network (OSTI)

sequence was added to the amino terminus of STIP to produce a new molecule, SLSTIP, which adopts site is in the same reading frame as that in STIP, and hence, after digesting pSPSG1 with Nco I and Pst- quence for the STIP polypeptide contained lysine codons at positions 29, 31, 46, 83, 101, 119, 136, 158

Walter, Peter

237

Thermal generation and mobility of charge carriers in collective proton transport in hydrogen-bonded chains  

SciTech Connect

The transport of protons in hydrogen-bonded systems is a long standing problem which has not yet obtained a satisfactorily theoretical description. Although this problem was examined first for ice, it is relevant in many systems and in particular in biology for the transport along proteins or for proton conductance across membranes, an essential process in cell life. The broad relevance makes the study of proton conduction very appealing. Since the original work of Bernal and Fowler on ice, the idea that the transport occurs through chains of hydrogen bonds has been well accepted. Such proton wires'' were invoked by Nagle and Morowitz for proton transport across membranes proteins and more recently across lipid bilayers. In this report, we assume the existence of such an hydrogen-bonded chain and discuss its consequences on the dynamics of the charge carriers. We show that this assumption leads naturally to the idea of soliton transport and we put a special emphasis on the role of the coupling between the protons and heavy ions motions. The model is presented. We show how the coupling affects strongly the dynamics of the charge carriers and we discuss the role it plays in the thermal generation of carriers. The work presented has been performed in 1986 and 87 with St. Pnevmatikos and N. Flyzanis and was then completed in collaboration with D. Hochstrasser and H. Buettner. Therefore the results presented in this part are not new but we think that they are appropriate in the context of this multidisciplinary workshop because they provide a rather complete example of the soliton picture for proton conduction. This paper discusses the thermal generation of the charge carriers when the coupling between the protons and heavy ions dynamics is taken into account. The results presented in this part are very recent and will deserve further analysis but they already show that the coupling can assist for the formation of the charge carriers.

Peyrard, M.; Boesch, R.; Kourakis, I. (Dijon Univ., 21 (France). Faculte des Sciences)

1991-01-01T23:59:59.000Z

238

Thermal generation and mobility of charge carriers in collective proton transport in hydrogen-bonded chains  

DOE Green Energy (OSTI)

The transport of protons in hydrogen-bonded systems is a long standing problem which has not yet obtained a satisfactorily theoretical description. Although this problem was examined first for ice, it is relevant in many systems and in particular in biology for the transport along proteins or for proton conductance across membranes, an essential process in cell life. The broad relevance makes the study of proton conduction very appealing. Since the original work of Bernal and Fowler on ice, the idea that the transport occurs through chains of hydrogen bonds has been well accepted. Such proton wires'' were invoked by Nagle and Morowitz for proton transport across membranes proteins and more recently across lipid bilayers. In this report, we assume the existence of such an hydrogen-bonded chain and discuss its consequences on the dynamics of the charge carriers. We show that this assumption leads naturally to the idea of soliton transport and we put a special emphasis on the role of the coupling between the protons and heavy ions motions. The model is presented. We show how the coupling affects strongly the dynamics of the charge carriers and we discuss the role it plays in the thermal generation of carriers. The work presented has been performed in 1986 and 87 with St. Pnevmatikos and N. Flyzanis and was then completed in collaboration with D. Hochstrasser and H. Buettner. Therefore the results presented in this part are not new but we think that they are appropriate in the context of this multidisciplinary workshop because they provide a rather complete example of the soliton picture for proton conduction. This paper discusses the thermal generation of the charge carriers when the coupling between the protons and heavy ions dynamics is taken into account. The results presented in this part are very recent and will deserve further analysis but they already show that the coupling can assist for the formation of the charge carriers.

Peyrard, M.; Boesch, R.; Kourakis, I. (Dijon Univ., 21 (France). Faculte des Sciences)

1991-01-01T23:59:59.000Z

239

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

Science Conference Proceedings (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

240

Fuel cell membrane humidification  

DOE Patents (OSTI)

A polymer electrolyte membrane fuel cell assembly has an anode side and a cathode side separated by the membrane and generating electrical current by electrochemical reactions between a fuel gas and an oxidant. The anode side comprises a hydrophobic gas diffusion backing contacting one side of the membrane and having hydrophilic areas therein for providing liquid water directly to the one side of the membrane through the hydrophilic areas of the gas diffusion backing. In a preferred embodiment, the hydrophilic areas of the gas diffusion backing are formed by sewing a hydrophilic thread through the backing. Liquid water is distributed over the gas diffusion backing in distribution channels that are separate from the fuel distribution channels.

Wilson, Mahlon S. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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

Membranes Improve Insulation Efficiency  

E-Print Network (OSTI)

It has been determined from extensive tests involving test models and home attics that loose fill and fiber batt insulation does not function as expected by the industry. The reason for this deficiency is current test methods do not accurately predict the magnitude of air infiltration into fiber insulation as used in home attics, radiant heat infiltration into the insulation during summer, or radiant heat loss through the insulation during winter conditions. The use of (1) moisture permeable membranes over the insulation, and (2) layered membranes between fiber batts to form closed cells in the insulation both dramatically improve the efficiency of the fiber insulation. The efficiency of this insulation will be improved to an even greater degree if these membranes reflect radiant heat as well as reduce convection air currents. Extensive tests have also been conducted which show that if moisture permeable membranes are used over fiber insulation, the moisture content of the insulation will be reduced.

Bullock, C. A.

1986-01-01T23:59:59.000Z

242

Microprobes aluminosilicate ceramic membranes  

DOE Patents (OSTI)

Methods have been developed to make mixed alumina-silicate and aluminosilicate particulate microporous ceramic membranes. One method involves the making of separate alumina and silica sols which are then mixed. Another method involves the creation of a combined sol with aluminosilicate particles. The resulting combined alumina and silica membranes have high surface area, a very small pore size, and a very good temperature stability.

Anderson, Marc A. (2114 Chadbourne Ave., Madison, WI 53705); Sheng, Guangyao (45 N. Orchard St., Madison, WI 53715)

1993-01-01T23:59:59.000Z

243

Battery utilizing ceramic membranes  

SciTech Connect

A thin film battery is disclosed based on the use of ceramic membrane technology. The battery includes a pair of conductive collectors on which the materials for the anode and the cathode may be spin coated. The separator is formed of a porous metal oxide ceramic membrane impregnated with electrolyte so that electrical separation is maintained while ion mobility is also maintained. The entire battery can be made less than 10 microns thick while generating a potential in the 1 volt range.

Yahnke, Mark S. (Berkeley, CA); Shlomo, Golan (Haifa, IL); Anderson, Marc A. (Madison, WI)

1994-01-01T23:59:59.000Z

244

Innovative oxygen separation membrane prototype  

SciTech Connect

Improvements are still needed to gas separation processes to gain industry acceptance of coal gasification systems. The Ion Transport Membrane (ITM) technology, being developed by the US Department of Energy and its partners, offers an opportunity to lower overall plant cost and improve efficiency compared to cryogenic distillation and pressure swing adsorption methods. The technology is based on a novel class of perovskite ceramic oxides which can selectively separate oxygen ions from a stream of air at high temperature and pressure. Those ions are transported across the ITM leaving non-permeate air which can be integrated with a fuel-fired gas system, enabling co-production of power and steam along with the concentrated, high-purity oxygen. The project is at the second phase, to scale up the ITM Oxygen ceramic devices to demonstrate the technology at the 1-5 tpd capability in the Subscale Engineering Prototype. A third phase to demonstrate commercial viability extends to the end of the decade. 2 figs.

NONE

2006-08-15T23:59:59.000Z

245

Mechanics of non-planar membranes with force-dipole activity  

E-Print Network (OSTI)

A study is made of how active membrane proteins can modify the long wavelength mechanics of fluid membranes. The activity of the proteins is modelled as disturbing the protein surroundings through non-local force distributions of which a force-dipole distribution is the simplest example. An analytic expression describing how the activity modifies the force-balance equation for the membrane surface is obtained in the form of a moment expansion of the force distribution. This expression allows for further studies of the consequences of the activity for non-planar membranes. In particular the active contributions to mechanical properties such as tension and bending moments become apparent. It is also explained how the activity can induce a hydrodynamic attraction between the active proteins in the membrane.

Michael A. Lomholt

2005-10-25T23:59:59.000Z

246

Transport Reactor Development Unit Modification to Provide a Syngas Slipstream at Elevated Conditions to Enable Separation of 100 LB/D of Hydrogen by Hydrogen Separation Membranes Year - 6 Activity 1.15 - Development of a National Center for Hydrogen Technology  

SciTech Connect

Gasification of coal when associated with carbon dioxide capture and sequestration has the potential to provide low-cost as well as low-carbon hydrogen for electric power, fuels or chemicals production. The key element to the success of this concept is inexpensive, effective separation of hydrogen from carbon dioxide in synthesis gas. Many studies indicate that membrane technology is one of the most, if not the most, economical means of accomplishing separation; however, the advancement of hydrogen separation membrane technology is hampered by the absence of experience or demonstration that the technology is effective economically and environmentally at larger scales. While encouraging performance has been observed at bench scale (less than 12 lb/d hydrogen), it would be imprudent to pursue a largescale demonstration without testing at least one intermediate scale, such as 100 lb/d hydrogen. Among its many gasifiers, the Energy & Environmental Research Center is home to the transport reactor demonstration unit (TRDU), a unit capable of firing 200—500 lb/hr of coal to produce 400 scfm of synthesis gas containing more than 200 lb/d of hydrogen. The TRDU and associated downstream processing equipment has demonstrated the capability of producing a syngas over a wide range of temperatures and contaminant levels — some of which approximate conditions of commercial-scale gasifiers. Until this activity, however, the maximum pressure of the TRDU’ s product syngas was 120 psig, well below the 400+ psig pressures of existing large gasifiers. This activity installed a high-temperature compressor capable of accepting the range of TRDU products up to 450°F and compressing them to 500 psig, a pressure comparable to some large scale gasifiers. Thus, with heating or cooling downstream of the TRDU compressor, the unit is now able to present a near-raw to clean gasifier synthesis gas containing more than 100 lb/d of hydrogen at up to 500 psig over a wide range of temperatures to hydrogen separation membranes or other equipment for development and demonstration.

Schlasner, Steven

2012-03-01T23:59:59.000Z

247

ORP-3 Rescues ER Membrane Expansions Caused by the VAPB-P56S Mutation in Familial ALS .  

E-Print Network (OSTI)

??A mutation in ER membrane protein VAPB is responsible for causing a familial form of ALS (ALS8). The VAPB-P56S mutation causes protein aggregation and a… (more)

Darbyson, Angie L.

2013-01-01T23:59:59.000Z

248

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

E-Print Network (OSTI)

ITM Syngas and ITM H2: Engineering Development of Ceramic Membrane Reactor Systems for Converting (U.S. DOE) and other members of the ITM Syngas/ITM H2 Team, is developing Ion Transport Membrane (ITM-scale centralized hydrogen production facilities with CO2 capture. The major goals of the ITM Syngas and ITM H2

249

Hydrogen separation membranes annual report for FY 2006.  

Science Conference Proceedings (OSTI)

The objective of this work is to develop dense ceramic membranes for separating hydrogen from other gaseous components in a nongalvanic mode, i.e., without using an external power supply or electrical circuitry. This goal of this project is to develop two types of dense ceramic membrane for producing hydrogen nongalvanically, i.e., without electrodes or external power supply, at commercially significant fluxes under industrially relevant operating conditions. The first type of membrane, hydrogen transport membranes (HTMs), will be used to separate hydrogen from gas mixtures such as the product streams from coal gasification, methane partial oxidation, and water-gas shift reactions. Potential ancillary uses of HTMs include dehydrogenation and olefin production, as well as hydrogen recovery in petroleum refineries and ammonia synthesis plants, the largest current users of deliberately produced hydrogen. The second type of membrane, oxygen transport membranes (OTMs), will produce hydrogen by nongalvanically removing oxygen that is generated when water dissociates at elevated temperatures. This report describes progress that was made during FY 2006 on the development of OTM and HTM materials.

Balachandran, U.; Chen, L.; Ciocco, M.; Doctor, R. D.; Dorris, S.E.; Emerson, J. E.; Fisher, B.; Lee, T. H.; Killmeyer, R. P.; Morreale,B.; Picciolo, J. J.; Siriwardane, R. V.; Song, S. J.

2007-02-05T23:59:59.000Z

250

The Automorphic Membrane  

E-Print Network (OSTI)

We present a 1-loop toroidal membrane winding sum reproducing the conjectured $M$-theory, four-graviton, eight derivative, $R^4$ amplitude. The $U$-duality and toroidal membrane world-volume modular groups appear as a Howe dual pair in a larger, exceptional, group. A detailed analysis is carried out for $M$-theory compactified on a 3-torus, where the target-space $Sl(3,\\Zint)\\times Sl(2,\\Zint)$ $U$-duality and $Sl(3,\\Zint)$ world-volume modular groups are embedded in $E_{6(6)}(\\Zint)$. Unlike previous semi-classical expansions, $U$-duality is built in manifestly and realized at the quantum level thanks to Fourier invariance of cubic characters. In addition to winding modes, a pair of new discrete, flux-like, quantum numbers are necessary to ensure invariance under the larger group. The action for these modes is of Born-Infeld type, interpolating between standard Polyakov and Nambu-Goto membrane actions. After integration over the membrane moduli, we recover the known $R^4$ amplitude, including membrane instantons. Divergences are disposed of by trading the non-compact volume integration for a compact integral over the two variables conjugate to the fluxes -- a constant term computation in mathematical parlance. As byproducts, we suggest that, in line with membrane/fivebrane duality, the $E_6$ theta series also describes five-branes wrapped on $T^6$ in a manifestly U-duality invariant way. In addition we uncover a new action of $E_6$ on ten dimensional pure spinors, which may have implications for ten dimensional super Yang--Mills theory. An extensive review of $Sl(3)$ automorphic forms is included in an Appendix.

Boris Pioline; Andrew Waldron

2004-04-02T23:59:59.000Z

251

Development of Practical Supported Ionic Liquid Membranes: A Systematic Approach  

DOE Green Energy (OSTI)

Supported liquid membranes (SLMs) are a class of materials that allow the researcher to utilize the wealth of knowledge available on liquid properties to optimize membrane performance. These membranes also have the advantage of liquid phase diffusivities, which are higher than those observed in polymers and grant proportionally greater permeabilities. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which may possess high CO2 solubility relative to light gases such as H2, are excellent candidates for this type of membrane since they are stable at elevated temperatures and have negligible vapor pressure. A study has been conducted evaluating the use of a variety of ionic liquids in supported ionic liquid membranes for the capture of CO2 from streams containing H2. In a joint project, researchers at the University of Notre Dame synthesized and characterized ionic liquids, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated membrane performance for the resulting materials. Several steps have been taken in the development of practical supported ionic liquid membranes. Proof-of-concept was established by showing that ionic liquids could be used as the transport media in SLMs. Results showed that ionic liquids are suitable media for gas transport, but the preferred polymeric supports were not stable at temperatures above 135oC. The use of cross-linked nylon66 supports was found to produce membranes mechanically stable at temperatures exceeding 300oC but CO2/H2 selectivity was poor. An ionic liquid whose selectivity does not decrease with increasing temperature was needed, and a functionalized ionic liquid that complexes with CO2 was used. An increase in CO2/H2 selectivity with increasing temperature over the range of 37 to 85oC was observed and the dominance of a facilitated transport mechanism established. The presentation will detail membrane development, the effect of increasing transmembrane pressure, and preliminary results dealing with other gas pairs and contaminants.

Luebke, D.R.; Ilconich, J.B.; Myers, C.R.; Pennline, H.W.

2007-11-01T23:59:59.000Z

252

Supported microporous ceramic membranes  

DOE Patents (OSTI)

A method for permformation of microporous ceramic membranes onto a porous support includes placing a colloidal suspension of metal or metal oxide particles on one side of the porous support and exposing the other side of the porous support to a drying stream of gas or a reactive gas stream so that the particles are deposited on the drying side of the support as a gel. The gel so deposited can be sintered to form a supported ceramic membrane useful for ultrafiltration, reverse osmosis, or molecular sieving having mean pore sizes less than 100 Angstroms.

Webster, Elizabeth (Madison, WI); Anderson, Marc (Madison, WI)

1993-01-01T23:59:59.000Z

253

Supported microporous ceramic membranes  

DOE Patents (OSTI)

A method for the formation of microporous ceramic membranes onto a porous support includes placing a colloidal suspension of metal or metal oxide particles on one side of the porous support and exposing the other side of the porous support to a drying stream of gas or a reactive gas stream so that the particles are deposited on the drying side of the support as a gel. The gel so deposited can be sintered to form a supported ceramic membrane useful for ultrafiltration, reverse osmosis, or molecular sieving having mean pore sizes less than 100 Angstroms. 4 figures.

Webster, E.; Anderson, M.

1993-12-14T23:59:59.000Z

254

Battery utilizing ceramic membranes  

DOE Patents (OSTI)

A thin film battery is disclosed based on the use of ceramic membrane technology. The battery includes a pair of conductive collectors on which the materials for the anode and the cathode may be spin coated. The separator is formed of a porous metal oxide ceramic membrane impregnated with electrolyte so that electrical separation is maintained while ion mobility is also maintained. The entire battery can be made less than 10 microns thick while generating a potential in the 1 volt range. 2 figs.

Yahnke, M.S.; Shlomo, G.; Anderson, M.A.

1994-08-30T23:59:59.000Z

255

Atomic structure of nitrate-binding protein crucial for photosynthetic productivity  

DOE Green Energy (OSTI)

Cyanobacteria, blue-green algae, are the most abundant autotrophs in aquatic environments and form the base of all aquatic food chains by fixing carbon and nitrogen into cellular biomass. The single most important nutrient for photosynthesis and growth is nitrate, which is severely limiting in many aquatic environments particularly the open ocean (1, 2). It is therefore not surprising that NrtA, the solute-binding component of the high-affinity nitrate ABC transporter, is the single-most abundant protein in the plasma membrane of these bacteria (3). Here we describe the first structure of a nitratespecific receptor, NrtA from Synechocystis sp. PCC 6803, complexed with nitrate and determined to a resolution of 1.5Å. NrtA is significantly larger than other oxyanionbinding proteins, representing a new class of transport proteins. From sequence alignments, the only other solute-binding protein in this class is CmpA, a bicarbonatebinding protein. Therefore, these organisms created a novel solute-binding protein for two of the most important nutrients; inorganic nitrogen and carbon. The electrostatic charge distribution of NrtA appears to force the protein off of the membrane while the flexible tether facilitates the delivery of nitrate to the membrane pore. The structure not only details the determinants for nitrate selectivity in NrtA, but also the bicarbonate specificity in CmpA. Nitrate and bicarbonate transport are regulated by the cytoplasmic proteins NrtC and CmpC, respectively. Interestingly, the residues lining the ligand binding pockets suggest that they both bind nitrate. This implies that the nitrogen and carbon uptake pathways are synchronized by intracellular nitrate and nitrite.3 The nitrate ABC transporter of cyanobacteria is composed of four polypeptides (Figure 1): a high-affinity periplasmic solute-binding lipoprotein (NrtA), an integral membrane permease (NrtB), a cytoplasmic ATPase (NrtD), and a unique ATPase/solute-binding fusion protein (NrtC) that regulates transport (4). NrtA binds both nitrate and nitrite (Kd = 0.3 mM) and is necessary for cell survival when nitrate is the primary nitrogen source (5). The role of NrtA is to scavenge nitrate/nitrite from the periplasm for delivery to the membrane permease, NrtB. The passage of solute through the transmembrane pore is linked to ATP hydrolysis by NrtC and NrtD. NrtD consists of a single ATPase domain. In contrast, NrtC contains both an ATPase domain and a Cterminal solute-binding domain that shares 50% amino acid sequence similarity with NrtA, and is required for the ammonium-mediated inhibition of nitrate transport (6, 7). Aside from the homologous transporter for bicarbonate, CmpABCD, there are no other known examples of ABC transporters that have an ATPase/solute-binding fusion component. The specificity of the nitrate transporter is conferred by NrtA (4). NrtA is ~49% identical (60% similar) in amino acid sequence to the bicarbonate receptor CmpA. In its entirety, it does not have significant homology to any other known protein. To elucidate the molecular determinants of nitrate specificity, we determined the crystal structure of the Synechocystis 6803 NrtA to 1.5 Å. While the general shape of NrtA is akin to that of other solute binding proteins, NrtA clearly represents a new and unique structural variant of these ‘C clamp’ proteins. From this structure and sequence alignments of other bicarbonate and nitrate transporters, the molecular basis for solute selectivity is clear and suggests that regulatory domains of both icarbonate and nitrate transport systems bind nitrate. Based on these findings, a model is presented that 4 demonstrates how such synergistic regulation of bicarbonate and nitrate transport is important in conserving energy during the process of carbon fixation and nitrogen assimilation.

Koropatkin, Nicole M.; Pakrasi, Himadri B.; Smith, Thomas J.

2006-06-27T23:59:59.000Z

256

Development of novel active transport membrande devices  

DOE Green Energy (OSTI)

Air Products has undertaken a research program to fabricate and evaluate gas separation membranes based upon promising ``active-transport`` (AT) materials recently developed in our laboratories. Active Transport materials are ionic polymers and molten salts which undergo reversible interaction or reaction with ammonia and carbon dioxide. The materials are useful for separating these gases from mixtures with hydrogen. Moreover, AT membranes have the unique property of possessing high permeability towards ammnonia and carbon dioxide but low permeability towards hydrogen and can thus be used to permeate these components from a gas stream while retaining hydrogen at high pressure.

Laciak, D.V.

1994-11-01T23:59:59.000Z

257

Development of dense ceramic membranes for methane conversion  

DOE Green Energy (OSTI)

The most significant cost associated with partial oxidation of methane to syngas is that of the oxygen plant. In this paper, the authors offer a technology, based on dense ceramic membranes, that uses air as the oxidant for methane conversion reactions, thus eliminating the need for the oxygen plant. Certain ceramic materials exhibit both electronic and ionic conductivities (of particular interest is oxygen-ion conductivity). These materials transport not only oxygen ions (functioning as selective oxygen separators) but also electrons back from the reactor side to the oxygen/reduction interface. No external electrodes are required, and, if the driving potential of transport is adequate, the partial oxidation reactions should be spontaneous. Such a system will operate without an externally applied potential. Oxygen is transported across the ceramic material in the form of oxygen ions, not oxygen molecules. Recent reports in the literature suggest that dense ceramic membranes made of these mixed conductors can successfully separate oxygen from air at flux rates that could be considered commercially feasible. Thus, these membranes have the potential to improve the economics of methane conversion processes. In principle, the dense ceramic materials can be shaped into hollow-tube reactors, in which air passes over the outside of the membrane and methane flows through the inside. The surfaces can also be reversed. The membrane is permeable to oxygen at high temperatures, but not to nitrogen or other gases. Thus, only oxygen from air can be transported through the membrane to the inside of the reactor surface, where it reacts with methane. Other geometric forms, such as honeycombs or corrugations, of the reactor are possible and can provide substantially greater surface areas for reaction.

Balachandran, U.; Dusek, J.T.; Maiya, P.S.; Ma, B.; Mieville, R.L. [Argonne National Lab., IL (United States). Energy Technology Div.; Kleefisch, M.S.; Udovich, C.A.; Fleisch, T.H. [Amoco Exploration/Production, Naperville, IL (United States); Bose, A.C. [USDOE Pittsburgh Energy Technology Center, PA (United States)

1995-06-01T23:59:59.000Z

258

Hydrogen-selective membrane  

DOE Patents (OSTI)

A hydrogen-selective membrane comprises a tubular porous ceramic support having a palladium metal layer deposited on an inside surface of the ceramic support. The thickness of the palladium layer is greater than about 10 {micro}m but typically less than about 20 {micro}m. The hydrogen permeation rate of the membrane is greater than about 1.0 moles/m{sup 2} s at a temperature of greater than about 500 C and a transmembrane pressure difference of about 1,500 kPa. Moreover, the hydrogen-to-nitrogen selectivity is greater than about 600 at a temperature of greater than about 500 C and a transmembrane pressure of about 700 kPa. Hydrogen can be separated from a mixture of gases using the membrane. The method may include the step of heating the mixture of gases to a temperature of greater than about 400 C and less than about 1000 C before the step of flowing the mixture of gases past the membrane. The mixture of gases may include ammonia. The ammonia typically is decomposed to provide nitrogen and hydrogen using a catalyst such as nickel. The catalyst may be placed inside the tubular ceramic support. The mixture of gases may be supplied by an industrial process such as the mixture of exhaust gases from the IGCC process. 9 figs.

Collins, J.P.; Way, J.D.

1997-07-29T23:59:59.000Z

259

Hydrogen-Selective Membrane  

SciTech Connect

A hydrogen-selective membrane comprises a tubular porous ceramic support having a palladium metal layer deposited on an inside surface of the ceramic support. The thickness of the palladium layer is greater than about 10 .mu.m but typically less than about 20 .mu.m. The hydrogen permeation rate of the membrane is greater than about 1.0 moles/m.sup.2.s at a temperature of greater than about 500.degree. C. and a transmembrane pressure difference of about 1,500 kPa. Moreover, the hydrogen-to-nitrogen selectivity is greater than about 600 at a temperature of greater than about 500.degree. C. and a transmembrane pressure of about 700 kPa. Hydrogen can be separated from a mixture of gases using the membrane. The method may include the step of heating the mixture of gases to a temperature of greater than about 400.degree. C. and less than about 1000.degree. C. before the step of flowing the mixture of gases past the membrane. The mixture of gases may include ammonia. The ammonia typically is decomposed to provide nitrogen and hydrogen using a catalyst such as nickel. The catalyst may be placed inside the tubular ceramic support. The mixture of gases may be supplied by an industrial process such as the mixture of exhaust gases from the IGCC process.

Collins, John P. (Boulder, CO); Way, J. Douglas (Boulder, CO)

1995-09-19T23:59:59.000Z

260

Hydrogen-selective membrane  

DOE Patents (OSTI)

A hydrogen-selective membrane comprises a tubular porous ceramic support having a palladium metal layer deposited on an inside surface of the ceramic support. The thickness of the palladium layer is greater than about 10 .mu.m but typically less than about 20 .mu.m. The hydrogen permeation rate of the membrane is greater than about 1.0 moles/m.sup.2. s at a temperature of greater than about 500.degree. C. and a transmembrane pressure difference of about 1,500 kPa. Moreover, the hydrogen-to-nitrogen selectivity is greater than about 600 at a temperature of greater than about 500.degree. C. and a transmembrane pressure of about 700 kPa. Hydrogen can be separated from a mixture of gases using the membrane. The method may include the step of heating the mixture of gases to a temperature of greater than about 400.degree. C. and less than about 1000.degree. C. before the step of flowing the mixture of gases past the membrane. The mixture of gases may include ammonia. The ammonia typically is decomposed to provide nitrogen and hydrogen using a catalyst such as nickel. The catalyst may be placed inside the tubular ceramic support. The mixture of gases may be supplied by an industrial process such as the mixture of exhaust gases from the IGCC process.

Collins, John P. (Boulder, CO); Way, J. Douglas (Boulder, CO)

1997-01-01T23:59:59.000Z

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261

Hydrogen-selective membrane  

DOE Patents (OSTI)

A hydrogen-selective membrane comprises a tubular porous ceramic support having a palladium metal layer deposited on an inside surface of the ceramic support. The thickness of the palladium layer is greater than about 10 {micro}m but typically less than about 20 {micro}m. The hydrogen permeation rate of the membrane is greater than about 1.0 moles/m{sup 2}s at a temperature of greater than about 500 C and a transmembrane pressure difference of about 1,500 kPa. Moreover, the hydrogen-to-nitrogen selectivity is greater than about 600 at a temperature of greater than about 500 C and a transmembrane pressure of about 700 kPa. Hydrogen can be separated from a mixture of gases using the membrane. The method may include the step of heating the mixture of gases to a temperature of greater than about 400 C and less than about 1000 C before the step of flowing the mixture of gases past the membrane. The mixture of gases may include ammonia. The ammonia typically is decomposed to provide nitrogen and hydrogen using a catalyst such as nickel. The catalyst may be placed inside the tubular ceramic support. The mixture of gases may be supplied by an industrial process such as the mixture of exhaust gases from the IGCC process. 9 figs.

Collins, J.P.; Way, J.D.

1995-09-19T23:59:59.000Z

262

HYDROGEN SEPARATION MEMBRANES  

DOE Green Energy (OSTI)

A likely membrane for future testing of high-temperature hydrogen separation from a gasification product stream was targeted as an inorganic analog of a dense-metal membrane, where the hydrogen would dissolve into and diffuse through the membrane structure. An amorphous membrane such as zinc sulfide appeared to be promising. Previously, ZnS film coating tests had been performed using an electron-beam vacuum coating instrument, with zinc films successfully applied to glass substrates. The coatings appeared relatively stable in air and in a simple simulated gasification atmosphere at elevated temperature. Because the electron-beam coating instrument suffered irreparable breakdown, several alternative methods were tested in an effort to produce a nitrogen-impermeable, hydrogen-permeable membrane on porous sintered steel substrates. None of the preparation methods proved successful in sealing the porous substrate against nitrogen gas. To provide a nitrogen-impermeable ZnS material to test for hydrogen permeability, two ZnS infrared sample windows were purchased. These relatively thick ''membranes'' did not show measurable permeation of hydrogen, either due to lack of absorption or a negligible permeation rate due to their thickness. To determine if hydrogen was indeed adsorbed, thermogravimetric and differential thermal analyses tests were performed on samples of ZnS powder. A significant uptake of hydrogen gas occurred, corresponding to a maximum of 1 mole H{sub 2} per 1 mole ZnS at a temperature of 175 C. The hydrogen remained in the material at ambient temperature in a hydrogen atmosphere, but approximately 50% would be removed in argon. Reheating in a hydrogen atmosphere resulted in no additional hydrogen uptake. Differential scanning calorimetry indicated that the hydrogen uptake was probably due to the formation of a zinc-sulfur-hydrogen species resulting in the formation of hydrogen sulfide. The zinc sulfide was found to be unstable above approximately 200 C, probably with the reduction to metallic zinc with the evolution of hydrogen sulfide. The work has shown that ZnS is not a viable candidate for a high-temperature hydrogen separation membrane.

Donald P. McCollor; John P. Kay

1999-08-01T23:59:59.000Z

263

Transportation Demand  

Gasoline and Diesel Fuel Update (EIA)

page intentionally left blank page intentionally left blank 69 U.S. Energy Information Administration | Assumptions to the Annual Energy Outlook 2011 Transportation Demand Module The NEMS Transportation Demand Module estimates transportation energy consumption across the nine Census Divisions (see Figure 5) and over ten fuel types. Each fuel type is modeled according to fuel-specific technology attributes applicable by transportation mode. Total transportation energy consumption is the sum of energy use in eight transport modes: light-duty vehicles (cars and light trucks), commercial light trucks (8,501-10,000 lbs gross vehicle weight), freight trucks (>10,000 lbs gross vehicle weight), buses, freight and passenger aircraft, freight and passenger rail, freight shipping, and miscellaneous

264

Ceramic membranes having macroscopic channels  

DOE Patents (OSTI)

Methods have been developed to make porous ceramic membranes having macroscopic channels therethrough. The novel membranes are formed by temporarily supporting the sol-gel membrane precursor on an organic support which is ultimately removed from the interior of the membrane, preferably by pyrolysis or by chemical destruction. The organic support may also include an inorganic metal portion that remains on destruction of the organic portion, providing structural support and/or chemical reactivity to the membrane. The channels formed when the organic support is destroyed provide the ability to withdraw small catalytic products or size-separated molecules from the metal oxide membrane. In addition, the channel-containing membranes retain all of the advantages of existing porous ceramic membranes.

Anderson, Marc A. (Madison, WI); Peterson, Reid A. (Madison, WI)

1996-01-01T23:59:59.000Z

265

Ceramic membranes having macroscopic channels  

DOE Patents (OSTI)

Methods have been developed to make porous ceramic membranes having macroscopic channels therethrough. The novel membranes are formed by temporarily supporting the sol-gel membrane precursor on an organic support which is ultimately removed from the interior of the membrane, preferably by pyrolysis or by chemical destruction. The organic support may also include an inorganic metal portion that remains on destruction of the organic portion, providing structural support and/or chemical reactivity to the membrane. The channels formed when the organic support is destroyed provide the ability to withdraw small catalytic products or size-separated molecules from the metal oxide membrane. In addition, the channel-containing membranes retain all of the advantages of existing porous ceramic membranes. 1 fig.

Anderson, M.A.; Peterson, R.A.

1996-09-03T23:59:59.000Z

266

Copper Palladium Hydrogen Separation Membranes  

This patent-pending technology, “Cu-Pd Hydrogen Separation Membranes with Reduced Palladium Content and Improved Performance,” consists of copper-palladium alloy compositions for hydrogen separation membranes that use less palladium and have a ...

267

Road Transportation.  

E-Print Network (OSTI)

?? The recession of the early 1990’s marked the starting point for a transformation of the Swedish transportation industry. Cost oriented production techniques by the… (more)

Gudmundsson, Erik

2008-01-01T23:59:59.000Z

268

Transportation Security  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

For Review Only 1 Transportation Security Draft Annotated Bibliography Review July 2007 Preliminary Draft - For Review Only 2 Work Plan Task * TEC STG Work Plan, dated 8206,...

269

WIPP Transportation  

NLE Websites -- All DOE Office Websites (Extended Search)

Transuranic Waste Transportation Container Documents Documents related to transuranic waste containers and packages. CBFO Tribal Program Information about WIPP shipments across...

270

Transportation Revolution  

NLE Websites -- All DOE Office Websites (Extended Search)

To transform the vehicle sector, the U.S. auto manufacturing industry is actively developing new technologies and products. This transportation revolution will also affect...

271

Driving Membrane Curvature | Advanced Photon Source  

NLE Websites -- All DOE Office Websites (Extended Search)

Unlocking the Nanoscale Secrets of Bird-Feather Colors Unlocking the Nanoscale Secrets of Bird-Feather Colors An Unlikely Route to Ferroelectricity How to Make a Splash Pressure-Tuning the Quantum Phase Transition in a Model 2-D Magnet Reappearing Superconductivity Surprises Scientists Science Highlights Archives: 2013 | 2012 | 2011 | 2010 2009 | 2008 | 2007 | 2006 2005 | 2004 | 2003 | 2002 2001 | 2000 | 1998 | Subscribe to APS Science Highlights rss feed Driving Membrane Curvature JUNE 14, 2012 Bookmark and Share Model of conformational change in the HIV gp41 fusion protein induced by cholesterol composition of lipid monolayers. In biological systems, membranes are as important as water. They form the barrier between the inner world, within our cells, where we perform the chemical reactions of life, and the outside environment.

272

Hydrogen separation using silica membranes  

Science Conference Proceedings (OSTI)

Silica membranes were synthesized on tubular supports of alumina by dipping in silica colloidal solutions. The quality and the performance of the silica membranes were tested by experiments on single gas permeation and gas separation of mixed N2, ... Keywords: Knudsen diffusion, colloidal solution, gas permeation, hydrogen separation, silica membranes

Salvador Alfaroa; Miguel A. Valenzuelaa; Pedro Bosch

2008-11-01T23:59:59.000Z

273

Hydrogen production by water dissociation using ceramic membranes - annual report for FY 2008.  

DOE Green Energy (OSTI)

The objective of this project is to develop dense ceramic membranes that, without using an external power supply or circuitry, can produce hydrogen via coal/coal gas-assisted water dissociation. This project grew from an effort to develop a dense ceramic membrane for separating hydrogen from gas mixtures such as those generated during coal gasification, methane partial oxidation, and water-gas shift reactions. That effort led to the development of various cermet (i.e., ceramic/metal composite) membranes that enable hydrogen production by two methods. In one method, a hydrogen transport membrane (HTM) selectively removes hydrogen from a gas mixture by transporting it through either a mixed protonic/electronic conductor or a hydrogen transport metal. In the other method, an oxygen transport membrane (OTM) generates hydrogen mixed with steam by removing oxygen that is generated through water splitting. This project focuses on the development of OTMs that efficiently produce hydrogen via the dissociation of water. Supercritical boilers offer very high-pressure steam that can be decomposed to provide pure hydrogen by means of OTMs. Oxygen resulting from the dissociation of steam can be used for coal gasification, enriched combustion, or synthesis gas production. Hydrogen and sequestration-ready CO{sub 2} can be produced from coal and steam by using the membrane being developed in this project. Although hydrogen can also be generated by high-temperature steam electrolysis, producing hydrogen by water splitting with a mixed-conducting membrane requires no electric power or electrical circuitry.

Balachandran, U.; Dorris, S. E.; Emerson, J. E.; Lee, T. H.; Lu, Y.; Park, C. Y.; Picciolo, J. J.; Energy Systems

2009-03-25T23:59:59.000Z

274

Hydrogen production by water dissociation using ceramic membranes - annual report for FY 2010.  

DOE Green Energy (OSTI)

The objective of this project is to develop dense ceramic membranes that can produce hydrogen via coal/coal gas-assisted water dissociation without using an external power supply or circuitry. This project grew from an effort to develop a dense ceramic membrane for separating hydrogen from gas mixtures such as those generated during coal gasification, methane partial oxidation, and water-gas shift reactions. That effort led to the development of various cermet (i.e., ceramic/metal composite) membranes that enable hydrogen production by two methods. In one method, a hydrogen transport membrane (HTM) selectively removes hydrogen from a gas mixture by transporting it through either a mixed protonic/electronic conductor or a hydrogen transport metal. In the other method, an oxygen transport membrane (OTM) generates hydrogen mixed with steam by removing oxygen that is generated through water splitting. This project focuses on the development of OTMs that efficiently produce hydrogen via the dissociation of water. Supercritical boilers offer very high-pressure steam that can be decomposed to provide pure hydrogen using OTMs. Oxygen resulting from the dissociation of steam can be used for coal gasification, enriched combustion, or synthesis gas production. Hydrogen and sequestration-ready CO{sub 2} can be produced from coal and steam by using the membrane being developed in this project. Although hydrogen can also be generated by high-temperature steam electrolysis, producing hydrogen by water splitting with a mixed-conducting membrane requires no electric power or electrical circuitry.

Balachandran, U.; Dorris, S. E.; Emerson, J. E.; Lee, T. H.; Lu, Y.; Park, C. Y.; Picciolo, J. J. (Energy Systems)

2011-03-14T23:59:59.000Z

275

Separation of Hydrogen Using an Electroless Deposited Thin-Film Palladium-Ceramic Composite Membrane  

DOE Green Energy (OSTI)

The primary objective of this project was to prepare and characterize a hydrogen permselective palladium-ceramic composite membrane for high temperature gas separations and catalytic membrane reactors. Electroless plating method was used to deposit a thin palladium film on microporous ceramic substrate. The objective of this paper is to discuss the preparation and characterization of a thin-film palladium-ceramic composite membrane for selective separation of hydrogen at elevated temperatures and pressures. In this paper, we also present a model to describe the hydrogen transport through the palladium-ceramic composite membrane in a cocurrent flow configuration.

Ilias, S.; King, F.G.; Fan, Ting-Fang; Roy, S. [North Carolina Agricultural and Technical State Univ., Greensboro, NC (United States). Dept. of Chemical Engineering

1996-12-31T23:59:59.000Z

276

Microsoft PowerPoint - Nano Sep Membrane for H2 Flux brief.ppt  

NLE Websites -- All DOE Office Websites (Extended Search)

Membrane separations are a key enabling technology for energy conversion devices. Ionic transport Membrane separations are a key enabling technology for energy conversion devices. Ionic transport membranes must have both proton and electronic conductivity to function as hydrogen separation membranes without an external power supply. In addition, membrane materials electronic conductivity or material crystal stability should not be greatly affected by the presence of contaminant gases such as CO 2 , CO, CH 4 , and H 2 O that are associated with steam reforming/water gas shift reactions. SRNL is managed and operated for the U.S. Department of Energy by Savannah River Nuclear Solutions, LLC glance at a  improved electronic conduction  suitable for hydrogen separation  separates contaminant gases  patent pending Background SRNL-L5210-2011-00005

277

Unsynchronized Translational and Rotational Diffusion of Nanocargo on a Living Cell Membrane  

SciTech Connect

A robust high-speed and high-precision single nanoparticle translational and rotational tracking method has been developed to directly monitor the interactions between transferrin-modified nanocargos (gold nanorods) and the membrane proteins prior to endocytosis. This approach shows that the translational and rotational diffusions of nanocargos on living cell membranes are unsynchronized in space and in time.

Xiao, Lehui; Wei, Lin; Liu, Chang; He, Yan; Yeung, Edward

2012-03-16T23:59:59.000Z

278

Membrane Stability Testing  

DOE Green Energy (OSTI)

The Electrosynthesis Co. Inc. (ESC) was contracted by the Westinghouse Savannah River Company to investigate the long term performance and durability of cell components (anode, membrane, cathode) in an electrochemical caustic recovery process using a simulated SRC liquid waste as anolyte solution. This report details the results of two long-term studies conducted using an ICI FM01 flow cell. This cell is designed and has previously been demonstrated to scale up directly into the commercial scale ICI FM21 cell.

Hobbs, D.T. [Westinghouse Savannah River Company, AIKEN, SC (United States)

1997-09-30T23:59:59.000Z

279

Novel Catalytic Membrane Reactors  

DOE Green Energy (OSTI)

There are many industrial catalytic organic reversible reactions with amines or alcohols that have water as one of the products. Many of these reactions are homogeneously catalyzed. In all cases removal of water facilitates the reaction and produces more of the desired chemical product. By shifting the reaction to right we produce more chemical product with little or no additional capital investment. Many of these reactions can also relate to bioprocesses. Given the large number of water-organic compound separations achievable and the ability of the Compact Membrane Systems, Inc. (CMS) perfluoro membranes to withstand these harsh operating conditions, this is an ideal demonstration system for the water-of-reaction removal using a membrane reactor. Enhanced reaction synthesis is consistent with the DOE objective to lower the energy intensity of U.S. industry 25% by 2017 in accord with the Energy Policy Act of 2005 and to improve the United States manufacturing competitiveness. The objective of this program is to develop the platform technology for enhancing homogeneous catalytic chemical syntheses.

Stuart Nemser, PhD

2010-10-01T23:59:59.000Z

280

Final Report - Membranes and MEA's for Dry, Hot Operating Conditions  

DOE Green Energy (OSTI)

The focus of this program was to develop a new Proton Exchange Membrane (PEM) which can operate under hotter, dryer conditions than the state of the art membranes today and integrate it into a Membrane Electrode Assembly (MEA). These MEA's should meet the performance and durability requirements outlined in the solicitation, operating under low humidification conditions and at temperatures ranging from -20���ºC to 120���ºC, to meet 2010 DOE technical targets for membranes. This membrane should operate under low humidification conditions and at temperatures ranging from -20���ºC to 120���ºC in order to meet DOE HFCIT 2010 commercialization targets for automotive fuel cells. Membranes developed in this program may also have improved durability and performance characteristics making them useful in stationary fuel cell applications. The new membranes, and the MEA�¢����s comprising them, should be manufacturable at high volumes and at costs which can meet industry and DOE targets. This work included: A) Studies to better understand factors controlling proton transport within the electrolyte membrane, mechanisms of polymer degradation (in situ and ex situ) and membrane durability in an MEA; B) Development of new polymers with increased proton conductivity over the range of temperatures from -20���ºC to 120���ºC and at lower levels of humidification and with improved chemical and mechanical stability; C) Development of new membrane additives for increased durability and conductivity under these dry conditions; D) Integration of these new materials into membranes and membranes into MEA�¢����s, including catalyst and gas diffusion layer selection and integration; E) Verification that these materials can be made using processes which are scalable to commercial volumes using cost effective methods; F) MEA testing in single cells using realistic automotive testing protocols. This project addresses technical barriers A (Durability) and C (Performance) from the Fuel Cells section of the 2005 Hydrogen, Fuel Cells and Infrastructure Technologies Program Multi-Year R&D Plan. In the course of this four-year program we developed a new PEM with improved proton conductivity, chemical stability and mechanical stability. We incorporated this new membrane into MEAs and evaluated performance and durability.

Hamrock, Steven J.

2011-06-30T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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

Transportation Market Distortions  

E-Print Network (OSTI)

of Highways, Volpe National Transportation Systems Center (Evaluating Criticism of Transportation Costing, VictoriaFrom Here: Evaluating Transportation Diversity, Victoria

Litman, Todd

2006-01-01T23:59:59.000Z

282

Defense Transportation - Center for Transportation Analysis  

NLE Websites -- All DOE Office Websites (Extended Search)

Defense Transportation The Center for Transportation Analysis provides analytical, planning, and operational support to defense transportation related projects. This includes the...

283

electrifyingthefuture transportation  

E-Print Network (OSTI)

programme of electrification and the potential introduction of diesel hybrids. The Department for Transport vehicles Wind turbine systems Industrial equipment The lab has full ethernet capability which will enable

Birmingham, University of

284

Sustainable Transportation  

Energy.gov (U.S. Department of Energy (DOE))

The Office of Energy Efficiency and Renewable Energy (EERE) leads U.S. researchers and other partners in making transportation cleaner and more efficient through solutions that put electric drive...

285

Transportation Network Modeling in Passenger Transportation  

E-Print Network (OSTI)

. Summary & Future work 2 #12;NETPLAN Energy and Transportation Integration model A modeling frameworkTransportation Network Modeling in NETPLAN Passenger Transportation Venkat Krishnan Eirini;Outline 1. Introduction to NETPLAN 2. Transportation modeling- A review Freight Passenger 3. Developed

Daniels, Thomas E.

286

Hydrogen Transport Membrane (HTM) for Separation of Pure ...  

Award by R&D Magazine, as one of the “most technologically significant new products” of 2004. Balachandran said the preferred source of hydrogen is

287

NETL: Gasification - Development of Ion-Transport Membrane Oxygen  

NLE Websites -- All DOE Office Websites (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)

288

Photochemical energy conversion by membrane-bound photoredox systems  

DOE Green Energy (OSTI)

Most of our effort during the past grant period has been directed towards investigating electron transfer processes involving redox proteins at lipid bilayer/aqueous interfaces. This theme, as was noted in our previous three year renewal proposal, is consistent with our goal of developing biomimetic solar energy conversion systems which utilize the unique properties of biological electron transfer molecules. Thus, small redox proteins such as cytochrome c, plastocyanin and ferredoxin function is biological photosynthesis as mediators of electron flow between the photochemical systems localized in the membrane, and more complex soluble or membrane-bound redox proteins which are designed to carry out specific biological tasks such as transbilayer proton gradient formation, dinitrogen fixation, ATP synthesis, dihydrogen synthesis, generation of strong reductants, etc. In these studies, we have utilized two principal experimental techniques, laser flash photolysis and cyclic voltammetry, both of which permit direct measurements of electron transfer processes.

Tollin, G.

1992-03-01T23:59:59.000Z

289

Supported liquid membrane electrochemical separators  

DOE Patents (OSTI)

Supported liquid membrane separators improve the flexibility, efficiency and service life of electrochemical cells for a variety of applications. In the field of electrochemical storage, an alkaline secondary battery with improved service life is described in which a supported liquid membrane is interposed between the positive and negative electrodes. The supported liquid membranes of this invention can be used in energy production and storage systems, electrosynthesis systems, and in systems for the electrowinning and electrorefining of metals.

Pemsler, J. Paul (Lexington, MA); Dempsey, Michael D. (Revere, MA)

1986-01-01T23:59:59.000Z

290

Oxygen-permeable ceramic membranes for gas separation  

DOE Green Energy (OSTI)

Mixed-conducting oxides have a wide range of applications, including fuel cells, gas separation systems, sensors, and electrocatalytic equipment. Dense ceramic membranes made of mixed-conducting oxides are particularly attractive for gas separation and methane conversion processes. Membranes made of Sr-Fe-Co oxide, which exhibits high combined electronic and oxygen ionic conductivities, can be used to selectively transport oxygen during the partial oxidation of methane to synthesis gas (syngas, i.e., CO + H{sub 2}). The authors have fabricated tubular Sr{sub 2}Fe{sub 2}CoO{sub 6+{delta}} membranes and tested them (some for more than 1,000 h) in a methane conversion reactor that was operating at 850--950 C. An oxygen permeation flux of {approx} 10 scc/cm{sup 2} {center_dot} min was obtained at 900 C in a tubular membrane with a wall thickness of 0.75 mm. Using a gas-tight electrochemical cell, the authors have also measured the steady-state oxygen permeability of flat Sr{sub 2}Fe{sub 2}CoO{sub 6+{delta}} membranes as a function of temperature and oxygen partial pressure(pO{sub 2}). Steady-state oxygen permeability increases with increasing temperature and with the difference in pO{sub 2} on the two sides of the membrane. At 900 C, an oxygen permeability of {approx} 2.5 scc/cm{sup 2} {center_dot} min was obtained in a 2.9-mm-thick membrane. This value agrees with that obtained in methane conversion reactor experiments. Current-voltage (I-V) characteristics determined in the gas-tight cell indicate that bulk effect, rather than surface exchange effect, is the main limiting factor for oxygen permeation of {approx} 1-mm-thick Sr{sub 2}Fe{sub 2}CoO{sub 6+{delta}} membranes at elevated temperatures (> 650 C).

Balachandran, U.; Ma, B.; Maiya, P.S.; Dusek, J.T.; Mieville, R.L.; Picciolo, J.J.

1998-02-01T23:59:59.000Z

291

Hydrogen separation membranes annual report for FY 2010.  

DOE Green Energy (OSTI)

The objective of this work is to develop dense ceramic membranes for separating hydrogen from other gaseous components in a nongalvanic mode, i.e., without using an external power supply or electrical circuitry. The goal of this project is to develop dense hydrogen transport membranes (HTMs) that nongalvanically (i.e., without electrodes or external power supply) separate hydrogen from gas mixtures at commercially significant fluxes under industrially relevant operating conditions. These membranes will be used to separate hydrogen from gas mixtures such as the product streams from coal gasification, methane partial oxidation, and water-gas shift reactions. Potential ancillary uses of HTMs include dehydrogenation and olefin production, as well as hydrogen recovery in petroleum refineries and ammonia synthesis plants, the largest current users of deliberately produced hydrogen. This report describes the results from the development and testing of HTM materials during FY 2010.

Balachandran, U.; Dorris, S. E; Emerson, J. E.; Lee, T. H.; Lu, Y.; Park, C. Y.; Picciolo, J. J. (Energy Systems)

2011-03-14T23:59:59.000Z

292

Development of mixed-conducting ceramic membrane for hydrogen separation.  

SciTech Connect

The Office of Fossil Energy of the US Department of Energy is formulating ''Vision 21,'' a program aimed at developing technologies for highly efficient power and coproduction plants that discharge almost no pollutants and close the carbon cycle. An integrated gasification combined cycle (IGCC) system is a likely modular component of a Vision 21 coproduction plant. IGCC technology is ideally suited for the coproduction of electricity and high-quality transportation fuel and/or a host of high-value chemicals. As part of the IGCC system, high-temperature membranes for separating hydrogen from coal gasification and other partial-oxidation-product streams are being considered. Thin and dense ceramic membranes fabricated from mixed protonic and electronic conductors provide a simple, efficient means for separating hydrogen from gas streams. Dense mixed-conducting ceramic membranes effect transport via ion- and electron-conducting mechanisms. Because these membranes have no interconnected porosity, selectively for hydrogen is nearly 100%. Hydrogen separation is achieved in a nongalvanic mode, i.e., without the need for electrodes and external power supply to drive the separation. BaCeO{sub 3}-based materials exhibit protonic conductivity that is significantly higher than its electronic conductivity. To enhance the electronic conductivity and increase hydrogen permeation, we have fabricated BaCeO{sub 3}-containing cermet membranes and used them in a nongalvanic mode to separate hydrogen from gas streams containing H{sub 2}, CO, CO{sub 2} and trace amounts of H{sub 2}S. Material selection, fabrication, performance as well as technical/technological challenges of the ceramic membranes for hydrogen separation are discussed in this talk.

Balachandran, U.; Dorris, S. E.; Lee, T. H.

1999-08-20T23:59:59.000Z

293

Electrokinesis is a microbial behavior that requires extracellular electron transport  

SciTech Connect

Shewanella species are widespread in nature, enjoying a cosmopolitan distribution in marine,freshwater, sedimentary and soil environments (1), and have attracted considerable attention in recent years because of their ability to reduce an extensive number of different electron 3 acceptors, including the solid (oxy)hydroxides of iron and manganese, such as Fe(OH)3 and MnO2, using one or more proposed mechanisms of extracellular electron transport (EET) (2, 3). The EET ability of Shewanella species is consistent with their ability to generate electric current in microbial fuel cells in the absence of exogenous electron shuttles (4). Various strategies of extracellular electron transfer have been proposed in metal-reducing microbes, including naturally-occurring (2) or biogenic (5-7) soluble mediators that ‘shuttle’ electrons from cells to acceptors, as well as direct transfer using multiheme cytochromes located on the cell exterior (8) and transfer via conductive nanowires (9-11). S. oneidensis MR-1 features several proteins that are involved with the transport of electrons to the exterior of the cell where they play an important role with regard to the reduction of solid electron acceptors such as metal oxides. These include two outer-membrane decaheme c-type cytochromes (MtrC and OmcA), a membrane spanning protein (MtrB), and two periplasmic multi-heme c-type cytochromes (MtrA and CymA). Deletion of the genes encoding any of these proteins leads to phenotypes that are greatly inhibited with regard to metal-oxide reduction and current production in microbial fuel cells (MFCs) (12, 13). The mutation of genes that code for proteins involved in the movement of cytochromes to the outer membrane also results in loss of metal-reducing phenotypes (13). The shewanellae are highly motile, by virtue of a single polar flagellum, and individual S. oneidensis MR-1 cells have been tracked swimming at speeds of up to, and sometimes over, 100 ?m/sec, although the average swimming speed of cells in a population is considerably lower (14). Research has also shown that S. oneidensis MR-1 also displays chemotactic responses to several soluble electron acceptors, including Fe(III) citrate (15, 16) and that the CheA-3 histidine protein kinase is required for this chemotactic behavior to be observed (14). Strain MR-1 has 4 also been shown to be very sensitive to the presence of electron acceptors. For example, strain MR-1 ceases motility after a short time in the absence of an electron acceptor; however motility can be restored upon the re-addition of an electron acceptor. Here we present data that suggest that the shewanellae exhibit a motility response not previously reported: we call it electrokinesis. This response occurs intermittently with the cells in proximity to a solid electron acceptor, such as a manganese oxide particle or the working electrode of an electrochemical cell, and motility is observed to increase after contact. In addition to increased swimming velocities, cells occasionally pause on the solid acceptor surface, then after brief contact (up to 1 second) the cells typically swim away in the opposite direction from which they approached. Electrokinesis is not a uniform response that can be observed in all cells, although if an electron shuttle is added, all cells rapidly become motile.

Harris, Howard W.; El-Naggar, Mohamed Y.; Bretschger, Orianna; Ward, Melissa J.; Romine, Margaret F.; Obraztsova, Anna; Nealson, Kenneth H.

2010-01-05T23:59:59.000Z

294

Carbon Dioxide Separation with Supported Ionic Liquid Membranes  

SciTech Connect

A practical form of CO2 capture at water-gas shift conditions in the IGCC process could serve the dual function of producing a pure CO2 stream for sequestration and forcing the equilibrium-limited shift reaction to completion enriching the stream in H2. The shift temperatures, ranging from the low temperature shift condition of 260°C to the gasification condition of 900°C, limit capture options by diminishing associative interactions which favor removal of CO2 from the gas stream. Certain sorption interactions, such as carbonate formation, remain available but generally involve exceptionally high sorbent regeneration energies that contribute heavily to parasitic power losses. Carbon dioxide selective membranes need only establish an equilibrium between the gas phase and sorption states in order to transport CO2, giving them a potential energetic advantage over other technologies. Supported liquid membranes take advantage of high, liquid phase diffusivities and a solution diffusion mechanism similar to that observed in polymeric membranes to achieve superior permeabilities and selectivites. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which possess high CO2 solubility relative to light gases such as H2, are excellent candidates for this type of membrane since they have negligible vapor pressure and are not susceptible to evaporation. A study has been conducted evaluating the use of ionic liquids including 1-hexyl-3-methyl-imidazolium bis(trifuoromethylsulfonyl)imide in supported ionic liquid membranes for the capture of CO2 from streams containing H2. In a joint project, researchers at the University of Notre Dame synthesized and characterized ionic liquids, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated the resulting materials for membrane performance. Improvements to the ionic liquid and support have allowed testing of these supported ionic liquid membranes at temperatures up to 300°C without loss of support mechanical stability or degradation of the ionic liquid. Substantial improvements in selectivity have also been observed at elevated temperature with the best membrane currently achieving optimum performance at 75°C.

Luebke, D.R.; Ilconich, J.B.; Pennline, H.W.; Myers, C.R.

2007-05-01T23:59:59.000Z

295

Olefin separation membrane and process  

DOE Patents (OSTI)

A membrane and process are disclosed for separating unsaturated hydrocarbons from fluid mixtures. The membrane and process differ from previously known membranes and processes, in that the feed and permeate streams can both be dry, the membrane need not be water or solvent swollen, and the membrane is characterized by a selectivity for an unsaturated hydrocarbon over a saturated hydrocarbon having the same number of carbon atoms of at least about 20, and a pressure-normalized flux of said unsaturated hydrocarbon of at least about 5{times}10{sup {minus}6}cm{sup 3}(STP)/cm{sup 2}{center_dot}s{center_dot}cmHg, said flux and selectivity being measured with a gas mixture containing said unsaturated and saturated hydrocarbons, and in a substantially dry environment. 4 figs.

Pinnau, I.; Toy, L.G.; Casillas, C.

1997-09-23T23:59:59.000Z

296

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Fuel cells have the potential to provide power for a wide variety of applications ranging from electronic devices to transportation vehicles. Cells operating with H2 and air as inputs and electric power and water as the only outputs are of particular interest because of their ability to produce power without degrading the environment. Polymer electrolyte membranes (PEMs), with hydrophilic, proton-conducting channels embedded in a structurally sound hydrophobic matrix, play a central role in the operation of polymer electrolyte fuel cells. PEMs are humidified by contact with air (the presence of water in PEMs is essential for proton transport). In addition, PEMs must transport protons to catalyst sites, which are typically crystalline solids such as platinum. The arrangement of the hydrophilic domains in the vicinity of both air and solid substrates is thus crucial. A University of California, Berkeley, and Berkeley Lab group has now provided the first set of data on morphology of PEMs at interfaces by a combination of x-ray scattering and microscopy.

297

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

Proton Channel Orientation in Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Wednesday, 27 January 2010 00:00 Fuel cells have the potential to provide power for a wide variety of applications ranging from electronic devices to transportation vehicles. Cells operating with H2 and air as inputs and electric power and water as the only outputs are of particular interest because of their ability to produce power without degrading the environment. Polymer electrolyte membranes (PEMs), with hydrophilic, proton-conducting channels embedded in a structurally sound hydrophobic matrix, play a central role in the operation of polymer electrolyte fuel cells. PEMs are humidified by contact with air (the presence of water in PEMs is essential for proton transport). In addition, PEMs must transport protons to catalyst sites, which are typically crystalline solids such as platinum. The arrangement of the hydrophilic domains in the vicinity of both air and solid substrates is thus crucial. A University of California, Berkeley, and Berkeley Lab group has now provided the first set of data on morphology of PEMs at interfaces by a combination of x-ray scattering and microscopy.

298

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Fuel cells have the potential to provide power for a wide variety of applications ranging from electronic devices to transportation vehicles. Cells operating with H2 and air as inputs and electric power and water as the only outputs are of particular interest because of their ability to produce power without degrading the environment. Polymer electrolyte membranes (PEMs), with hydrophilic, proton-conducting channels embedded in a structurally sound hydrophobic matrix, play a central role in the operation of polymer electrolyte fuel cells. PEMs are humidified by contact with air (the presence of water in PEMs is essential for proton transport). In addition, PEMs must transport protons to catalyst sites, which are typically crystalline solids such as platinum. The arrangement of the hydrophilic domains in the vicinity of both air and solid substrates is thus crucial. A University of California, Berkeley, and Berkeley Lab group has now provided the first set of data on morphology of PEMs at interfaces by a combination of x-ray scattering and microscopy.

299

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Fuel cells have the potential to provide power for a wide variety of applications ranging from electronic devices to transportation vehicles. Cells operating with H2 and air as inputs and electric power and water as the only outputs are of particular interest because of their ability to produce power without degrading the environment. Polymer electrolyte membranes (PEMs), with hydrophilic, proton-conducting channels embedded in a structurally sound hydrophobic matrix, play a central role in the operation of polymer electrolyte fuel cells. PEMs are humidified by contact with air (the presence of water in PEMs is essential for proton transport). In addition, PEMs must transport protons to catalyst sites, which are typically crystalline solids such as platinum. The arrangement of the hydrophilic domains in the vicinity of both air and solid substrates is thus crucial. A University of California, Berkeley, and Berkeley Lab group has now provided the first set of data on morphology of PEMs at interfaces by a combination of x-ray scattering and microscopy.

300

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Fuel cells have the potential to provide power for a wide variety of applications ranging from electronic devices to transportation vehicles. Cells operating with H2 and air as inputs and electric power and water as the only outputs are of particular interest because of their ability to produce power without degrading the environment. Polymer electrolyte membranes (PEMs), with hydrophilic, proton-conducting channels embedded in a structurally sound hydrophobic matrix, play a central role in the operation of polymer electrolyte fuel cells. PEMs are humidified by contact with air (the presence of water in PEMs is essential for proton transport). In addition, PEMs must transport protons to catalyst sites, which are typically crystalline solids such as platinum. The arrangement of the hydrophilic domains in the vicinity of both air and solid substrates is thus crucial. A University of California, Berkeley, and Berkeley Lab group has now provided the first set of data on morphology of PEMs at interfaces by a combination of x-ray scattering and microscopy.

Note: This page contains sample records for the topic "membrane transport proteins" 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

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Proton Channel Orientation in Block-Copolymer Electrolyte Membranes Print Fuel cells have the potential to provide power for a wide variety of applications ranging from electronic devices to transportation vehicles. Cells operating with H2 and air as inputs and electric power and water as the only outputs are of particular interest because of their ability to produce power without degrading the environment. Polymer electrolyte membranes (PEMs), with hydrophilic, proton-conducting channels embedded in a structurally sound hydrophobic matrix, play a central role in the operation of polymer electrolyte fuel cells. PEMs are humidified by contact with air (the presence of water in PEMs is essential for proton transport). In addition, PEMs must transport protons to catalyst sites, which are typically crystalline solids such as platinum. The arrangement of the hydrophilic domains in the vicinity of both air and solid substrates is thus crucial. A University of California, Berkeley, and Berkeley Lab group has now provided the first set of data on morphology of PEMs at interfaces by a combination of x-ray scattering and microscopy.

302

Gas separation with glass membranes  

DOE Green Energy (OSTI)

The Department of Energy (DOE) is seeking to develop high temperature, high pressure inorganic membrane technology to perform a variety of gas separation processes to improve the efficiency and economics of advanced power generation systems such as direct coal-fueled turbines (DCFT) and the integrated gasification combined cycle process (IGCC). The temperatures encountered in these power generation systems are far above the temperature range for organic membrane materials. Inorganic materials such as ceramics are therefore the most likely membrane materials for use at high temperatures. This project focussed on silica glass fiber membranes made by PPG Industries (Pittsburgh, PA). The goals were both experimental and theoretical. The first objective was to develop a rational theory for the performance of these membranes. With existing theories as a starting point, a new theory was devised to explain the unusual molecular sieving'' behavior exhibited by these glass membranes. An apparatus was then devised for making permeation performance measurements at conditions of interest to DOE (temperatures to 2000[degrees]F; pressures to 1000 psia). With this apparatus, gas mixtures could be made typical of coal combustion or coal gasification processes, these gases could be passed into a membrane test cell, and the separation performance determined. Data were obtained for H[sub 2]/CO,N[sub 2]/CO[sub 2], 0[sub 2]/N[sub 2], and NH[sub 3]/N[sub 2] mixtures and for a variety of pure component gases (He, H[sub 2], CO[sub 2], N[sub 2], CO, NH[sub 3]). The most challenging part of the project turned out to be the sealing of the membrane at high temperatures and pressures. The report concludes with an overview of the practical potential of these membranes and of inorganic membranes in general of DOE and other applications.

Roberts, D.L.; Abraham, L.C.; Blum, Y.; Way, J.D.

1992-05-01T23:59:59.000Z

303

Ionic Liquid Membranes for Carbon Dioxide Separation  

SciTech Connect

Recent scientific studies are rapidly advancing novel technological improvements and engineering developments that demonstrate the ability to minimize, eliminate, or facilitate the removal of various contaminants and green house gas emissions in power generation. The Integrated Gasification Combined Cycle (IGCC) shows promise for carbon dioxide mitigation not only because of its higher efficiency as compared to conventional coal firing plants, but also due to a higher driving force in the form of high partial pressure. One of the novel technological concepts currently being developed and investigated is membranes for carbon dioxide (CO2) separation, due to simplicity and ease of scaling. A challenge in using membranes for CO2 capture in IGCC is the possibility of failure at elevated temperatures or pressures. Our earlier research studies examined the use of ionic liquids on various supports for CO2 separation over the temperature range, 37°C-300°C. The ionic liquid, 1-hexyl-3methylimidazolium Bis(trifluoromethylsulfonyl)imide, ([hmim][Tf2N]), was chosen for our initial studies with the following supports: polysulfone (PSF), poly(ether sulfone) (PES), and cross-linked nylon. The PSF and PES supports had similar performance at room temperature, but increasing temperature caused the supported membranes to fail. The ionic liquid with the PES support greatly affected the glass transition temperature, while with the PSF, the glass transition temperature was only slightly depressed. The cross-linked nylon support maintained performance without degradation over the temperature range 37-300°C with respect to its permeability and selectivity. However, while the cross-linked nylon support was able to withstand temperatures, the permeability continued to increase and the selectivity decreased with increasing temperature. Our studies indicated that further testing should examine the use of other ionic liquids, including those that form chemical complexes with CO2 based on amine interactions. The hypothesis is that the performance at the elevated temperatures could be improved by allowing a facilitated transport mechanism to become dominant. Several amine-based ionic liquids were tested on the cross-linked nylon support. It was found that using the amine-based ionic liquid did improve selectivity and permeability at higher temperature. The hypothesis was confirmed, and it was determined that the type of amine used also played a role in facilitated transport. Given the appropriate aminated ionic liquid with the cross-linked nylon support, it is possible to have a membrane capable of separating CO2 at IGCC conditions. With this being the case, the research has expanded to include separation of other constituents besides CO2 (CO, H2S, etc.) and if they play a role in membrane poisoning or degradation. This communication will discuss the operation of the recently fabricated ionic liquid membranes and the impact of gaseous components other than CO2 on their performance and stability.

Myers, C.R.; Ilconich, J.B.; Luebke, D.R.; Pennline, H.W.

2008-07-12T23:59:59.000Z

304

PROTON-CONDUCTING DENSE CERAMIC MEMBRANES FOR HYDROGEN SEPARATION  

DOE Green Energy (OSTI)

Dense perovskite-type structured ceramic membranes, SrCe{sub 0.95}Tm{sub 0.05}O{sub 3} (SCTm), of different thickness, were prepared by the dry-press method. Membrane thickness was varied from 3 mm to 150 {micro}m. The hydrogen permeation flux was found to be inversely proportional to the thickness of the dense films, indicating that the bulk diffusion rather than the surface reaction played a dominant role in the H{sub 2} transport through these dense membranes within the studied thickness range. Hydrogen permeation flux increases with increasing upstream hydrogen partial pressure and decreasing downstream hydrogen partial pressure. The activation energy for hydrogen permeation through the SCTm membrane is about 116 kJ/mol in 600-700 C and 16 kJ/mol in 750-950 C. This indicates a change in the electrical and protonic conduction mechanism at around 700 C. Pd-Cu thin films were synthesized with elemental palladium and copper targets by the sequential R.F. sputter deposition on porous substrates. Pd-Cu alloy films could be formed after proper annealing. The deposited Pd-Cu films were gas-tight. This result demonstrated the feasibility of obtaining an ultrathin SCTm film by the sequential sputter deposition of Sr, Ce and Tm metals followed by proper annealing and oxidation. Such ultrathin SCTm membranes will offer sufficiently high hydrogen permeance for practical applications.

Jerry Y. S. Lin; Scott Cheng; Vineet Gupta

2003-12-01T23:59:59.000Z

305

Carbon molecular sieve (CMS) membranes are microporous carbon membranes formed by pyrolysis of polymers. CMS membranes  

E-Print Network (OSTI)

Carbon molecular sieve (CMS) membranes are microporous carbon membranes formed by pyrolysis mixtures such as carbon dioxide / methane and ethane / ethylene separations. While there are many reports including carbon dioxide, methane, ethane and ethylene and also with selected two-component mixtures

McQuade, D. Tyler

306

Carbon Dioxide Separation with Supported Ionic Liquid Membranes  

DOE Green Energy (OSTI)

Supported liquid membranes are a class of materials that allow the researcher to utilize the wealth of knowledge available on liquid properties as a direct guide in the development of a capture technology. These membranes also have the advantage of liquid phase diffusivities higher than those observed in polymeric membranes which grant proportionally greater permeabilities. The primary shortcoming of the supported liquid membranes demonstrated in past research has been the lack of stability caused by volatilization of the transport liquid. Ionic liquids, which possess high carbon dioxide solubility relative to light gases such as hydrogen, are an excellent candidate for this type of membrane since they have negligible vapor pressure and are not susceptible to evaporation. A study has been conducted evaluating the use of several ionic liquids, including 1-hexyl-3-methyl-imidazolium bis(trifuoromethylsulfonyl)imide, 1-butyl-3-methyl-imidazolium nitrate, and 1-ethyl-3-methyl-imidazolium sulfate in supported ionic liquid membranes for the capture of carbon dioxide from streams containing hydrogen. In a joint project, researchers at the University of Notre Dame lent expertise in ionic liquid synthesis and characterization, and researchers at the National Energy Technology Laboratory incorporated candidate ionic liquids into supports and evaluated the resulting materials for membrane performance. Initial results have been very promising with carbon dioxide permeabilities as high as 950 barrers and significant improvements in carbon dioxide/hydrogen selectivity over conventional polymers at 37C and at elevated temperatures. Results include a comparison of the performance of several ionic liquids and a number of supports as well as a discussion of innovative fabrication techniques currently under development.

Luebke, D.R.; Ilconich, J.B.; Myers, C.R.; Pennline, H.W.

2007-04-01T23:59:59.000Z

307

Application of Inorganic Membrane Technology to Hydrogen-hydrocarbon Separations  

DOE Green Energy (OSTI)

Separation efficiency for hydrogen/light hydrocarbon mixtures was examined for three inorganic membranes. Five binary gas mixtures were used in this study: H{sub 2}/CH{sub 4} , H{sub 2}/C{sub 2}H{sub 6}, H{sub 2}/C{sub 3}H{sub 8}, He/CO{sub 2}, and He/Ar. The membranes examined were produced during a development program at the Inorganic Membrane Technology Laboratory in Oak Ridge and provided to us for this testing. One membrane was a (relatively) large-pore-diameter Knudsen membrane, and the other two had much smaller pore sizes. Observed separation efficiencies were generally lower than Knudsen separation but, for the small-pore membranes, were strongly dependent on temperature, pressure, and gas mixture, with the most condensable gases showing the strongest effect. This finding suggests that the separation is strongly influenced by surface effects (i.e., adsorption and diffusion), which enhance the transport of the heavier and more adsorption-prone component and may also physically impede flow of the other component. In one series of experiments, separation reversal was observed (the heavier component preferentially separating to the low-pressure side of the membrane). Trends showing increased separation factors at higher temperatures as well as observations of some separation efficiencies in excess of that expected for Knudsen flow suggest that at higher temperatures, molecular screening effects were observed. For most of the experiments, surface effects were stronger and thus apparently overshadow molecular sieving effects.

Trowbridge, L.D.

2003-06-30T23:59:59.000Z

308

A Robust and Rapid Method of Producing Soluble, Stable, and Functional G-Protein Coupled Receptors  

E-Print Network (OSTI)

Membrane proteins, particularly G-protein coupled receptors (GPCRs), are notoriously difficult to express. Using commercial E.coli cell-free systems with the detergent Brij-35, we could rapidly produce milligram quantities ...

Baaske, Philipp

309

High resolution neutron imaging of water in the polymer electrolyte fuel cell membrane  

Science Conference Proceedings (OSTI)

Water transport in the ionomeric membrane, typically Nafion{reg_sign}, has profound influence on the performance of the polymer electrolyte fuel cell, in terms of internal resistance and overall water balance. In this work, high resolution neutron imaging of the Nafion{reg_sign} membrane is presented in order to measure water content and through-plane gradients in situ under disparate temperature and humidification conditions.

Mukherjee, Partha P [Los Alamos National Laboratory; Makundan, Rangachary [Los Alamos National Laboratory; Spendelow, Jacob S [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Hussey, D S [NIST; Jacobson, D L [NIST; Arif, M [NIST

2009-01-01T23:59:59.000Z

310

Conception and construction of an LPG tank using a composite membrane technology  

SciTech Connect

TECHNIGAZ and TOTAL C.F.P. have developed a new LPG storage technology derived from the membrane concept used for LNG storage and transportation. This technology called GMS uses a composite membrane as primary barrier. A 2 000 m/sup 3/ storage pilot unit, based on that concept, is under construction in TOTAL's refinery at DUNKIRK (France) since September 1983.

Fuvel, P.; Claude, J.

1985-03-01T23:59:59.000Z

311

Dense ceramic membranes for methane conversion  

DOE Green Energy (OSTI)

This report focuses on a mechanism for oxygen transport through mixed- oxide conductors as used in dense ceramic membrane reactors for the partial oxidation of methane to syngas (CO and H{sub 2}). The in-situ separation of O{sub 2} from air by the membrane reactor saves the costly cryogenic separation step that is required in conventional syngas production. The mixed oxide of choice is SrCo{sub 0.5}FeO{sub x}, which exhibits high oxygen permeability and has been shown in previous studies to possess high stability in both oxidizing and reducing conditions; in addition, it can be readily formed into reactor configurations such as tubes. An understanding of the electrical properties and the defect dynamics in this material is essential and will help us to find the optimal operating conditions for the conversion reactor. In this paper, we discuss the conductivities of the SrFeCo{sub 0.5}O{sub x} system that are dependent on temperature and partial pressure of oxygen. Based on the experimental results, a defect model is proposed to explain the electrical properties of this system. The oxygen permeability of SrFeCo{sub 0.5}O{sub x} is estimated by using conductivity data and is compared with that obtained from methane conversion reaction.

Balachandran, U.; Mieville, R.L.; Ma, B. [Argonne National Lab., IL (United States); Udovich, C.A. [Amoco Oil Co., Naperville, IL (United States)

1996-05-01T23:59:59.000Z

312

Apparatus for tensioning a heliostat membrane  

DOE Patents (OSTI)

An apparatus for pneumatically or hydraulically tensioning a membrane, which stretched membrane can support a reflective surface for use as a heliostat in a solar energy collection system.

Sallis, Daniel V. (P.O. Box 554, Littleton, CO 80120)

1986-01-01T23:59:59.000Z

313

Anion Exchange Membranes for Fuel Cells  

NLE Websites -- All DOE Office Websites (Extended Search)

Anion Exchange Membranes for Fuel Cells Andrew M. Herring CSM Bryan Pivovar NREL 1 Anion Exchange Membranes (Presented to Parallel Breakout Sessions) * Stability Challenges -...

314

Role Of Calcium In Membrane Fusion.  

E-Print Network (OSTI)

??This project is focused on understanding the role of calcium in membrane fusion at the atomic level. Membrane fusion is an intense area of experimental… (more)

Issa, Zeena Kas

2010-01-01T23:59:59.000Z

315

Theoretical and experimental investigation of membrane distillation.  

E-Print Network (OSTI)

??Invented in the 1960s, membrane distillation is an emerging technology for water treatment attracting more attention since 1980s. There are four configurations of membrane distillations… (more)

Zhang, Jianhua

2011-01-01T23:59:59.000Z

316

Lyotropic Liquid Crystal (LLC) Nanofiltration Membranes - Energy ...  

Vehicles and Fuels; Wind Energy; Partners (27) Visual Patent Search; ... Description Control of membrane pore structure is a major challenge for membrane manufacturers.

317

Gas Separations using Ceramic Membranes  

DOE Green Energy (OSTI)

This project has been oriented toward the development of a commercially viable ceramic membrane for high temperature gas separations. A technically and commercially viable high temperature gas separation membrane and process has been developed under this project. The lab and field tests have demonstrated the operational stability, both performance and material, of the gas separation thin film, deposited upon the ceramic membrane developed. This performance reliability is built upon the ceramic membrane developed under this project as a substrate for elevated temperature operation. A comprehensive product development approach has been taken to produce an economically viable ceramic substrate, gas selective thin film and the module required to house the innovative membranes for the elevated temperature operation. Field tests have been performed to demonstrate the technical and commercial viability for (i) energy and water recovery from boiler flue gases, and (ii) hydrogen recovery from refinery waste streams using the membrane/module product developed under this project. Active commercializations effort teaming with key industrial OEMs and end users is currently underway for these applications. In addition, the gas separation membrane developed under this project has demonstrated its economical viability for the CO2 removal from subquality natural gas and landfill gas, although performance stability at the elevated temperature remains to be confirmed in the field.

Paul KT Liu

2005-01-13T23:59:59.000Z

318

Durable, Low-cost, Improved Fuel Cell Membranes  

Science Conference Proceedings (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 Arkema’s 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 Arkema’s 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

319

DUAL PHASE MEMBRANE FOR HIGH TEMPERATURE CO2 SEPARATION  

SciTech Connect

This project is intended to expand upon the previous year's research en route to the development of a sustainable dual phase membrane for CO{sub 2} separation. It was found that the pores within the supports had to be less than 9 {micro}m in order to maintain the stability of the dual phase membrane. Pores larger than 9 {micro}m would be unable to hold the molten carbonate phase in place, rendering the membrane ineffective. Calculations show that 80% of the pore volume of the 0.5 media grade metal support was filled with the molten carbonate. Information obtained from EDS and SEM confirmed that the molten carbonate completely infiltrated the pores on both the contact and non-contact size of the metal support. Permeation tests for CO{sub 2} and N{sub 2} at 450-750 C show very low permeance of those two gases through the dual phase membrane, which was expected due to the lack of ionization of those two 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 quite rapidly, while predictions showed that permeance should have continued to increase. XRD data obtained form the surface of the membrane indicated the formation of lithium iron oxides on the support. This layer has a very low conductivity, which drastically reduces the flow of electrons to the CO{sub 2}/O{sub 2} gas mixture, limiting the formation of the ionic species. These results indicate that the use of stainless steel supports in a high temperature oxidative environment can lead to decreased performance of the membranes. This revelation has created the need for an oxidation resistant support, which can be gained by the use of a ceramic-type membrane. Future research efforts will be directed towards preparation of a new ceramic-carbonate dual phase membrane. The membrane will based on an oxide ceramic support that has an oxidation resistance better than the metal support and high electronic conductivity (1200-1500 S/cm) in the interested temperature range (400-600 C).

Jerry Y.S. Lin; Seungjoon Chung; Matthew Anderson

2005-12-01T23:59:59.000Z

320

Surface Segregation in a PdCu Alloy Hydrogen Separation Membrane  

DOE Green Energy (OSTI)

Separation of hydrogen from mixed gas streams is an important step for hydrogen generation technologies, including hydrocarbon reforming and coal/biomass gasification. Dense palladium-based membranes have received significant attention for this application because of palladium’s ability to dissociatively adsorb molecular hydrogen at its surface for subsequent transport of hydrogen atoms through its bulk. Alloying palladium with minor components, like copper, has been shown to improve both the membrane’s structural characteristics and resistance to poisoning of its catalytic surface [1]. Surface segregation—a composition difference between the bulk material and its surface—is common in alloys and can affect important surface processes. Rational design of alloy membranes requires that surface segregation be understood, and possibly controlled. In this work, we examine surface segregation in a polycrystalline Pd70Cu30 hydrogen separation membrane as a function of thermal treatment and adsorption of hydrogen sulfide.

Miller, J.B.; Matranga, C.S.; Gellman, A.J.

2007-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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.


321

Transportation Issues  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Issues Issues and Resolutions - Compilation of Laboratory Transportation Work Package Reports Prepared for U.S. Department of Energy Used Fuel Disposition Campaign Compiled by Paul McConnell Sandia National Laboratories September 30, 2012 FCRD-UFD-2012-000342 Transportation Issues and Resolutions ii September 2012 Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. DISCLAIMER This information was prepared as an account of work sponsored by an agency of the U.S. Government. Neither the U.S. Government nor any

322

LNG transportation  

Science Conference Proceedings (OSTI)

In the beginning of 1965, the participants to the starting up of first French LNG transportation system between ARZEW and LE HAVRE were indeed pioneers when they started the cool-down of the three tanks of LE HAVRE, with a LNG freight delivered by old liberty-ship ''BEAUVAIS''. Could they forecast the development of LNG industry in FRANCE and in the world and imagine that modest 'JULES VERNE' and his two english brothers would have, 25 years later, 80 successors - more than five times as big, for the main part of them, that 12 liquefaction plants would be running in the world, supplying about twenty LNG terminals. For the first time, a country - FRANCE - can draw the lessons from the exploitation of the 3 LNG transportation systems during a long period. That is the subject of the present paper.

Picard, J.

1988-01-01T23:59:59.000Z

323

Transportation Security  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

For Review Only 1 Transportation Security Draft Annotated Bibliography Review July 2007 Preliminary Draft - For Review Only 2 Work Plan Task * TEC STG Work Plan, dated 8/2/06, Product #16, stated: "Develop an annotated bibliography of publicly-available documents related to security of radioactive material transportation." * Earlier this year, a preliminary draft annotated bibliography on this topic was developed by T-REX , UNM, to initially address this STG Work Plan Task. Preliminary Draft - For Review Only 3 Considerations in Determining Release of Information * Some "Publicly-available" documents could potentially contain inappropriate information according to standards set by DOE information security policy and DOE Guides. - Such documents would not be freely

324

Transportation Energy Futures  

E-Print Network (OSTI)

A Comparative Analysis of Future Transportation Fuels. ucB-prominentlyin our transportation future, powering electricTransportation Energy Futures Daniel Sperling Mark A.

DeLuchi, Mark A.

1989-01-01T23:59:59.000Z

325

Achieving Sustainable Transportation  

E-Print Network (OSTI)

a serious concern for future transportation planning, but itplanning for the future. Transportation should be at the topsustainable transportation look like? Again, the future will

Mason, Jonathan

2006-01-01T23:59:59.000Z

326

Transportation and its Infrastructure  

E-Print Network (OSTI)

Transport and its infrastructure Coordinating Lead Authors:5 Transport and its infrastructure Chandler, K. , E. Eberts,5 Transport and its infrastructure Sausen, R. , I. Isaksen,

2007-01-01T23:59:59.000Z

327

Intelligent Transport Systems  

E-Print Network (OSTI)

in Sustainable Urban Transport: City Interview Synthesis (of Leeds, Institute for Transport Studies, forthcoming.I NTELLIGENT TRANSPORT SYSTEMS LINKING TECHNOLOGY AND

Deakin, Elizabeth; Frick, Karen Trapenberg; Skabardonis, Alexander

2009-01-01T23:59:59.000Z

328

Preface: Nonclassical Transport  

E-Print Network (OSTI)

models of solute transport in highly heterogeneous geologicSemenov. 2008b. Nonclassical transport processes in geologicand L. Matveev. 2008. Transport regimes and concentration

Bolshov, L.

2010-01-01T23:59:59.000Z

329

Sustainability and Transport  

E-Print Network (OSTI)

Gilbert is a Toronto-based transport and energy consultantof the forthcoming book Transport Revolutions: Making theand substantial transition to transport systems based on

Gilbert, Richard

2006-01-01T23:59:59.000Z

330

Nuclear dynamics : from importin beta regulation of nuclear pore assembly to identification of novel vertebrate proteins involved in mRNA export.  

E-Print Network (OSTI)

??The cell nucleus contains the genetic materials of an organism and allows selective nucleocytoplasmic transport via the nuclear pores embedded in the nuclear membranes. In… (more)

Phung, Quang

2009-01-01T23:59:59.000Z

331

Transportation Planning & Decision Science Group Transportation...  

NLE Websites -- All DOE Office Websites (Extended Search)

Poster Presentations: Stacy Davis - "Transportation Data Programs: Transportation Energy Data Book, Vehicle Technologies Market Report, and the Vehicle Technologies Fact of...

332

Dense ceramic membranes for partial oxygenation of methane  

DOE Green Energy (OSTI)

The most significant cost associated with partial oxidation of methane to syngas is that of the oxygen plant. In this paper, the authors offer a technology that is based on dense ceramic membranes and that uses air as the oxidant for methane-conversion reactions, thus eliminating the need for the oxygen plant. Certain ceramic materials exhibit both electronic and ionic conductivities (of particular interest is oxygen-ion conductivity). These materials transport not only oxygen ions (functioning as selective oxygen separators) but also electrons back from the reactor side to the oxygen/reduction interface. No external electrodes are required and if the driving potential of transport is sufficient, the partial oxidation reactions should be spontaneous. Such a system will operate without an externally applied potential. Oxygen is transported across the ceramic material in the form of oxygen anions, not oxygen molecules. In principle, the dense ceramic materials can be shaped into a hollow-tube reactor, with air passed over the outside of the membrane and methane through the inside. The membrane is permeable to oxygen at high temperatures, but not to nitrogen or any other gas. Long tubes of La-Sr-Fe-Co-O (SFC) membrane were fabricated by plastic extrusion, and thermal stability of the tubes was studied as a function of oxygen partial pressure by high-temperature XRD. Mechanical properties were measured and found to be acceptable for a reactor material. Fracture of certain SFC tubes was the consequence of an oxygen gradient that introduced a volumetric lattice difference between the inner and outer walls. However, tubes made with a particular stoichiometry (SFC-2) provided methane conversion efficiencies of >99% in a reactor. Some of the reactor tubes have operated for up to {approx} 1,000 h.

Balachandran, U.; Dusek, J.T.; Sweeney, S.M.; Mieville, R.L.; Maiya, P.S. [Argonne National Lab., IL (United States). Energy Technology Div.; Kleefisch, M.S.; Pei, S.; Kobylinski, T.P. [Amoco Research Center, Naperville, IL (United States); Bose, A.C. [USDOE Pittsburgh Energy Technology Center, PA (United States)

1994-05-01T23:59:59.000Z

333

Corrugated Membrane Fuel Cell Structures  

DOE Green Energy (OSTI)

By corrugating the fuel cell membrane electrode structure, Ion Power?s goal is to realize both the Pt utilization targets as well as the power density targets of the DOE. This will be achieved by demonstrating a fuel cell single cell (50 cm2) with a twofold increase in the membrane active area over the geometric area of the cell by corrugating the MEA structure. The corrugating structure must be able to demonstrate the target properties of < 10 mOhm-cm2 electrical resistance at > 20 psi compressive strength over the active area, in combination with offering at least 80% of power density that can be achieved by using the same MEA in a flat plate structure. Corrugated membrane fuel cell structures also have the potential to meet DOE power density targets by essentially packaging more membrane area into the same fuel cell volume as compared to conventional stack constructions.

Grot, Stephen [President, Ion Power Inc.

2013-09-30T23:59:59.000Z

334

Layered plasma polymer composite membranes  

DOE Patents (OSTI)

Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is [>=]2 and is the number of selective layers. 2 figs.

Babcock, W.C.

1994-10-11T23:59:59.000Z

335

Gas separation membrane module assembly  

SciTech Connect

A gas-separation membrane module assembly and a gas-separation process using the assembly. The assembly includes a set of tubes, each containing gas-separation membranes, arranged within a housing. The housing contains a tube sheet that divides the space within the housing into two gas-tight spaces. A permeate collection system within the housing gathers permeate gas from the tubes for discharge from the housing.

Wynn, Nicholas P (Palo Alto, CA); Fulton, Donald A. (Fairfield, CA)

2009-03-31T23:59:59.000Z

336

Calcium-Mediated Regulation of Proton-Coupled Sodium Transport - Final Report  

SciTech Connect

The long-term goal of our experiments was to understand mechanisms that regulate energy coupling by ion currents in plants. Activities of living organisms require chemical, mechanical, osmotic or electrical work, the energy for which is supplied by metabolism. Adenosine triphosphate (ATP) has long been recognized as the universal energy currency, with metabolism supporting the synthesis of ATP and the hydrolysis of ATP being used for the subsequent work. However, ATP is not the only energy currency in living organisms. A second and very different energy currency links metabolism to work by the movement of ions passing from one side of a membrane to the other. These ion currents play a major role in energy capture and they support a range of physiological processes from the active transport of nutrients to the spatial control of growth and development. In Arabidopsis thaliana (Arabidopsis), the activity of a plasma membrane Na+/H+ exchanger, SALT OVERLY SENSITIVE1 (SOS1), is essential for regulation of sodium ion homeostasis during plant growth in saline conditions. Mutations in SOS1 result in severely reduced seedling growth in the presence of salt compared to the growth of wild type. SOS1 is a secondary active transporter coupling movement of sodium ions out of the cell using energy stored in the transplasma membrane proton gradient, thereby preventing the build-up of toxic levels of sodium in the cytosol. SOS1 is regulated by complexes containing the SOS2 and CALCINEURIN B-LIKE10 (CBL10) or SOS3 proteins. CBL10 and SOS3 (also identified as CBL4) encode EF-hand calcium sensors that interact physically with and activate SOS2, a serine/threonine protein kinase. The CBL10/SOS2 or SOS3/SOS2 complexes then activate SOS1 Na+/H+ exchange activity. We completed our studies to understand how SOS1 activity is regulated. Specifically, we asked: (1) how does CBL10 regulate SOS1 activity? (2) What role do two putative CBL10-interacting proteins play in SOS1 regulation? (3) Are there differences in the regulation and/or activity of SOS1 in plants differing in their adaptation to salinity?

Schumaker, Karen S [Professor] [Professor

2013-10-24T23:59:59.000Z

337

Investigating the adsorption and transport of water in MFI zeolite pores for water desalination  

E-Print Network (OSTI)

The permeability of reverse osmosis membranes is limited by the diffusive transport of water across a non-porous polyamide active layer. Alternatively, fabricating a microporous active layer capable of rejecting salt ions ...

Humplik, Thomas

2010-01-01T23:59:59.000Z

338

Transportation Research Internship Program  

E-Print Network (OSTI)

Transportation Research Internship Program Civil & Coastal Engineering Overview The Transportation Research Internship Program (TRIP) is conducted by the Transportation Research Center (TRC) and the Center is to provide undergraduates an exciting opportunity to learn about transportation engineering

Slatton, Clint

339

Poly(vinyl alcohol)-based buffering membranes for isoelectric trapping separations  

E-Print Network (OSTI)

Isoelectric trapping (IET) in multicompartment electrolyzers (MCE) has been widely used for the electrophoretic separation of ampholytic compounds such as proteins. In IET, the separation occurs in the buffering membranes that form a step-wise pH gradient in the MCE. Typically, buffering membranes have been made by copolymerizing acrylamide with Immobiline compounds, which are acidic and basic acylamido buffers. One major problem, however, is that these buffering membranes are not stable when exposed to high concentrations of acid and base due to hydrolysis of the amide bonds. Poly(vinyl alcohol)-based, or PVA-based, membranes were made as an alternative to the polyacrylamide-based membranes since they provide more hydrolytic and mechanical stability. Four mid-pH, PVA-based buffering membranes that contain single ampholytes were synthesized. These buffering membranes were used to trap small molecular weight pI markers for up to three hours, and were also used in desalting experiments to remove strong electrolytes from a solution of ampholytes. Additionally, the membranes were used in IET experiments to separate mixtures of pI markers, and to fractionate the major proteins in chicken egg white. The membranes did not show any degradation when stored in 3 M NaOH for up to 6 months and were shown to tolerate current densities as high as 16 mA/cm2. In addition, six series of PVA-based membranes, whose pH values can be tuned over the 3 < pH < 10 range, were synthesized by covalently binding aminodicarboxylic acids, and monoamines or diamines to the PVA matrix. These tunable buffering membranes were used in trapping experiments to trap ampholytes for up to three hours, and in desalting experiments to remove strong electrolytes from a solution of ampholytes. These tunable buffering membranes were also used in IET experiments to separate proteins, some with pI values that differ by only 0.1 pH unit. The tunable buffering membranes did not show any signs of degradation when exposed to 3 M NaOH for up to 3 months, and could be used in IET experiments with current densities as high as 20 mA/cm2. These tunable buffering membranes are expected to broaden the application areas of isoelectric trapping separations.

Craver, Helen C.

2007-05-01T23:59:59.000Z

340

Transport in a Microfluidic Catalytic Reactor  

DOE Green Energy (OSTI)

A study of the heat and mass transfer, flow, and thermodynamics of the reacting flow in a catalytic microreactor is presented. Methanol reforming is utilized in the fuel processing system driving a micro-scale proton exchange membrane fuel cell. Understanding the flow and thermal transport phenomena as well as the reaction mechanisms is essential for improving the efficiency of the reforming process as well as the quality of the processed fuel. Numerical studies have been carried out to characterize the transport in a silicon microfabricated reactor system. On the basis of these results, optimized conditions for fuel processing are determined.

Park, H G; Chung, J; Grigoropoulos, C P; Greif, R; Havstad, M; Morse, J D

2003-04-30T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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

Hydrogen purifier module with membrane support  

DOE Patents (OSTI)

A hydrogen purifier utilizing a hydrogen-permeable membrane to purify hydrogen from mixed gases containing hydrogen is disclosed. Improved mechanical support for the permeable membrane is described, enabling forward or reverse differential pressurization of the membrane, which further stabilizes the membrane from wrinkling upon hydrogen uptake.

A hydrogen purifier utilizing a hydrogen-permeable membrane to purify hydrogen from mixed gases containing hydrogen is disclosed. Improved mechanical support for the permeable membrane is described, enabling forward or reverse differential pressurization of the membrane, which further stabilizes the membrane from wrinkling upon hydrogen uptake.

2012-07-24T23:59:59.000Z

342

Probing Membrane Protein Dimerization in the Native Bilayer ...  

Science Conference Proceedings (OSTI)

... Native Bilayer Environment. Kalina Hristova, Department of Materials Science and Engineering Johns Hopkins University. ...

343

Vertebrate Membrane Proteins: Structure, Function, and Insights from Biophysical Approaches  

E-Print Network (OSTI)

produce multiple products used in signaling such as inositol-1,4,5-triphosphate, diacylglycerol and cardiovascular diseases are proinflammatory products of arachidonic acid de- rived from oxidation by 5 bond (4­5 kcal/mol), but these minor fluctuations can lead to productive catalytic events (Vendruscolo

Palczewski, Krzysztof

344

Effective Energy Function for Proteins in Lipid Membranes Themis Lazaridis*  

E-Print Network (OSTI)

, City College of the City University of New York, New York, New York ABSTRACT A simple extension system by making the reference solvation free energy of each atom dependent on the vertical coordinate structures are known at atomic resolution. Under these circumstances, computer modeling could make

Lazaridis, Themis

345

Hydrogen production by water dissociation using ceramic membranes. Annual report for FY 2007.  

DOE Green Energy (OSTI)

The objective of this project is to develop dense ceramic membranes that, without using an external power supply or circuitry, can produce hydrogen via coal/coal gas-assisted water dissociation. This project grew out of an effort to develop a dense ceramic membrane for separating hydrogen from gas mixtures such as those generated during coal gasification, methane partial oxidation, and water-gas shift reactions [1]. That effort led to the development of various cermet (i.e., ceramic/metal composite) membranes that enable hydrogen to be produced by two methods. In one method, a hydrogen transport membrane (HTM) selectively removes hydrogen from a gas mixture by transporting it through either a mixed protonic/electronic conductor or a hydrogen transport metal. In the other method, an oxygen transport membrane (OTM) generates hydrogen mixed with steam by removing oxygen that is generated through water splitting [1, 2]. This project focuses on the development of OTMs that efficiently produce hydrogen via the dissociation of water. Supercritical boilers offer very high-pressure steam that can be decomposed to provide pure hydrogen by means of OTMs. Oxygen resulting from the dissociation of steam can be used for coal gasification, enriched combustion, or synthesis gas production. Hydrogen and sequestration-ready CO{sub 2} can be produced from coal and steam by using the membrane being developed in this project. Although hydrogen can also be generated by high-temperature steam electrolysis, producing hydrogen by water splitting with a mixed-conducting membrane requires no electric power or electrical circuitry.

Balachandran, U.; Chen, L.; Dorris, S. E.; Emerson, J. E.; Lee, T. H.; Park, C. Y.; Picciolo, J. J.; Song, S. J.; Energy Systems

2008-03-04T23:59:59.000Z

346

A Dynamic Two-Phase Flow Model of Proton Exchange Membrane Fuel Cells  

E-Print Network (OSTI)

A dynamic two phase flow model for proton exchange membrane (PEM) fuel cells is presented. The two dimensional along-the-channel model includes the two phase flow of water (gaseous and liquid) in the porous diffusion layers and in the catalyst layers, as well as the transport of the species in the gas phase. Moreover, proton and water transport in the membrane and the oxygen reduction reaction in the cathodic catalyst layer is accounted for. The discretisation of the resulting flow equations is done by a mixed finite element approach. Based on this the transport equations for the species in each phase are discretised by a finite volume scheme. The coupled mixed finite element/finite volume approach gives the spatially resolved water and gas saturation and the species concentrations. In order to describe the charge transport in the fuel cell the Poisson equations for the electrons and protons are solved by using Galerkin finite element schemes.

Karsten Kühn; K. Kühn; Mario Ohlberger; Jürgen O. Schumacher; C. Ziegler; R. Klöfkorn; Karsten Kühn Ab; Mario Ohlberger Cd; Jürgen O. Schumacher A; Christoph Ziegler; Robert Klöfkorn C

2003-01-01T23:59:59.000Z

347

Tensioning device for a stretched membrane collector  

DOE Patents (OSTI)

Disclosed is a solar concentrating collector comprising an elastic membrane member for concentrating sunlight, a frame for holding the membrane member in plane and in tension, and a tensioning means for varying the tension of the membrane member. The tensioning means is disposed at the frame and is adapted to releasably attach the membrane member thereto. The tensioning means is also adapted to uniformly and symmetrically subject the membrane member to stretching forces such that membrane stresses produced thereby are distributed uniformly over a thickness of the membrane member and reciprocal twisting moments are substantially prevented from acting about said frame.

Murphy, Lawrence M. (Lakewood, CO)

1984-01-01T23:59:59.000Z

348

Tensioning device for a stretched membrane collector  

DOE Patents (OSTI)

Disclosed is a solar concentrating collector comprising an elestic membrane member for concentrating sunlight, a frame for holding the membrane member in plane and in tension, and a tensioning means for varying the tension of the membrane member. The tensioning means is disposed at the frame and is adapted to releasably attach the membrane member thereto. The tensioning means is also adapted to uniformly and symmetrically subject the membrane member to stretching forces such that membrane stresses produced thereby are distributed uniformly over a thickness of the membrane member and reciprocal twisting moments are substantially prevented from acting about said frame.

Murphy, L.M.

1984-01-01T23:59:59.000Z

349

TRANSPORTATION SYSTEMS Transportation systems are the building  

E-Print Network (OSTI)

TRANSPORTATION SYSTEMS Transportation systems are the building blocks of modern society. Efficient mobility improves the quality of life. However, transportation systems by their very nature also affect quality. The transportation systems graduate pro- gram provides in-depth knowledge on the design

Wang, Yuhang

350

NOVEL NANOCOMPOSITE MEMBRANE STRUCTURES FOR H2 SEPARATIONS  

DOE Green Energy (OSTI)

This report explores possible methods of improving CO{sub 2} selectivity in polymer based membranes. The first method investigated using basic nanoparticles to enhance the solubility of acid gases in nanocomposite membranes, thus enhancing the overall acid gas/light gas selectivity (e.g., CO{sub 2}/H{sub 2}, CO{sub 2}/CH{sub 4}, etc.). The influence of nanoparticle surface chemistry on nanocomposite morphology and transport properties will be determined experimentally in a series of poly(1-trimethylsilyl-1-propyne). Additional factors (e.g., chemical reaction of the particles with the polymers) have been considered, as necessary, during the course of the investigation. The second method investigated using polar polymers such as crosslinked poly(ethylene oxide) and poly(ether-b-amide) to improve CO{sub 2} sorption and thereby increase CO{sub 2} permeability and CO{sub 2}/light gas selectivity. For both types of materials, CO{sub 2} and light gas permeabilities have been characterized. The overall objective was to improve the understanding of materials design strategies to improve acid gas transport properties of membranes.

Benny D. Freeman

2005-03-31T23:59:59.000Z

351

UNDERSTANDING THE EFFECTS OF COMPRESSION AND CONSTRAINTS ON WATER UPTAKE OF FUEL-CELL MEMBRANES  

Science Conference Proceedings (OSTI)

Accurate characterization of polymer-electrolyte fuel cells (PEFCs) requires understanding the impact of mechanical and electrochemical loads on cell components. An essential aspect of this relationship is the effect of compression on the polymer membrane?s water-uptake behavior and transport properties. However, there is limited information on the impact of physical constraints on membrane properties. In this paper, we investigate both theoretically and experimentally how the water uptake of Nafion membrane changes under external compression loads. The swelling of a compressed membrane is modeled by modifying the swelling pressure in the polymer backbone which relies on the changes in the microscopic volume of the polymer. The model successfully predicts the water content of the compressed membrane measured through in-situ swelling-compression tests and neutron imaging. The results show that external mechanical loads could reduce the water content and conductivity of the membrane, especially at lower temperatures, higher humidities, and in liquid water. The modeling framework and experimental data provide valuable insight for the swelling and conductivity of constrained and compressed membranes, which are of interest in electrochemical devices such as batteries and fuel cells.

Kusoglu, Ahmet; Kienitz, Briian; Weber, Adam

2011-08-24T23:59:59.000Z

352

Intelligent Transportation Systems - Center for Transportation Analysis  

NLE Websites -- All DOE Office Websites (Extended Search)

Intelligent Transportation Systems Intelligent Transportation Systems The Center for Transportation Analysis does specialty research and development in intelligent transportation systems. Intelligent Transportation Systems (ITS) are part of the national strategy for improving the operational safety, efficiency, and security of our nation's highways. Since the early 1990s, ITS has been the umbrella under which significant efforts have been conducted in research, development, testing, deployment and integration of advanced technologies to improve the measures of effectiveness of our national highway network. These measures include level of congestion, the number of accidents and fatalities, delay, throughput, access to transportation, and fuel efficiency. A transportation future that includes ITS will involve a significant improvement in these

353

Liquid membrane purification of biogas  

SciTech Connect

Conventional gas purification technologies are highly energy intensive. They are not suitable for economic removal of CO{sub 2} from methane obtained in biogas due to the small scale of gas production. Membrane separation techniques on the other hand are ideally suited for low gas production rate applications due to their modular nature. Although liquid membranes possess a high species permeability and selectivity, they have not been used for industrial applications due to the problems of membrane stability, membrane flooding and poor operational flexibility, etc. A new hollow-fiber-contained liquid membrane (HFCLM) technique has been developed recently. This technique overcomes the shortcomings of the traditional immobilized liquid membrane technology. A new technique uses two sets of hydrophobic, microporous hollow fine fibers, packed tightly in a permeator shell. The inter-fiber space is filled with an aqueous liquid acting as the membrane. The feed gas mixture is separated by selective permeation of a species through the liquid from one fiber set to the other. The second fiber set carries a sweep stream, gas or liquid, or simply the permeated gas stream. The objectives (which were met) of the present investigation were as follows. To study the selective removal of CO{sub 2} from a model biogas mixture containing 40% CO{sub 2} (the rest being N{sub 2} or CH{sub 4}) using a HFCLM permeator under various operating modes that include sweep gas, sweep liquid, vacuum and conventional permeation; to develop a mathematical model for each mode of operation; to build a large-scale purification loop and large-scale permeators for model biogas separation and to show stable performance over a period of one month.

Majumdar, S.; Guha, A.K.; Lee, Y.T.; Papadopoulos, T.; Khare, S. (Stevens Inst. of Tech., Hoboken, NJ (United States). Dept. of Chemistry and Chemical Engineering)

1991-03-01T23:59:59.000Z

354

Studies of signaling domains in model and biological membranes through advanced imaging techniques: final report.  

SciTech Connect

Cellular membranes have complex lipid and protein structures that are laterally organized for optimized molecular recognition and signal transduction processes. Knowledge of nanometer-scale lateral organization and its function is of great importance in the analysis of receptor-based signaling. In model membranes, we studied in detail the chemical and physical factors which result in lateral organization of lipids and lipid-mediated protein sequestration into signaling domains. In biological membranes, we mapped the location and follow the dynamic activity of specific membrane proteins involved in the immunological response of mast cells. These studies were enabled by our development of advanced imaging methods that provided both high spatial resolution and sensitivity to dynamical processes. Our technical approach was to combine the high sensitivity and time resolution of fluorescence imaging with the high lateral resolution of atomic force microscopy (AFM). Simultaneous fluorescence and AFM imaging allows correlation of the distribution and dynamic activity of specific biomolecules via fluorescence labeling with complete topographic information of the membrane. Overall, our unique imaging capabilities enabled us to examine membrane structure and function with much greater detail than was previously possible and thus provide a better understanding of cellular signaling.

Oliver, Janet (University of New Mexico School of Medicine, Albuquerque, NM); Pfeiffer, Janet (New Mexico School of Medicine, Albuquerque, NM); Wilson, Bridget (University of New Mexico School of Medicine, Albuquerque, NM); Burns, Alan Richard

2006-10-01T23:59:59.000Z

355

Wrapping of ellipsoidal nano-particles by fluid membranes  

E-Print Network (OSTI)

Membrane budding and wrapping of particles, such as viruses and nano-particles, play a key role in intracellular transport and have been studied for a variety of biological and soft matter systems. We study nano-particle wrapping by numerical minimization of bending, surface tension, and adhesion energies. We calculate deformation and adhesion energies as a function of membrane elastic parameters and adhesion strength to obtain wrapping diagrams. We predict unwrapped, partially-wrapped, and completely-wrapped states for prolate and oblate ellipsoids for various aspect ratios and particle sizes. In contrast to spherical particles, where partially-wrapped states exist only for finite surface tensions, partially-wrapped states for ellipsoids occur already for tensionless membranes. In addition, the partially-wrapped states are long-lived, because of an increased energy cost for wrapping of the highly-curved tips. Our results suggest a lower uptake rate of ellipsoidal particles by cells and thereby a higher virulence of tubular viruses compared with icosahedral viruses, as well as co-operative budding of ellipsoidal particles on membranes.

Sabyasachi Dasgupta; Thorsten Auth; Gerhard Gompper

2013-03-22T23:59:59.000Z

356

Incorporation of Outer Membrane Protein OmpG in Lipid Membranes: Protein-lipid Interactions and -Barrel Orientation  

E-Print Network (OSTI)

in this ex- periment. sizes. The intermediate sizes perform better with 100 µF performing the best of the lot to produce DC voltage and boosted to an appropriate level by a charge pump The RF harvester also includes environments exhibit diurnal and weather-induced variations in light level, but are generally much more

Kleinschmidt, Jörg H.

357

Dual Phase Membrane for High Temperature CO2 Separation  

SciTech Connect

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

358

High temperature size selective membranes  

DOE Green Energy (OSTI)

The objective of this research is to develop a high temperature size selective membrane capable of separating gas mixture components from each other based on molecular size, using a molecular sieving mechanism. The authors are evaluating two concepts: a composite of a carbon molecular sieve (CMS) with a tightly defined pore size distribution between 3 and 4 {angstrom}, and a microporous supporting matrix which provides mechanical strength and resistance to thermal degradation, and a sandwich of a CMS film between the porous supports. The high temperature membranes the authors are developing can be used to replace the current low-temperature unit operations for separating gaseous mixtures, especially hydrogen, from the products of the water gas shift reaction at high temperatures. Membranes that have a high selectivity and have both thermal and chemical stability would improve substantially the economics of the coal gasification process. These membranes can also improve other industrial processes such as the ammonia production and oil reform processes where hydrogen separation is crucial. Results of tests on a supported membrane and an unsupported carbon film are presented.

Yates, S.F.; Zhou, S.J.; Anderson, D.J.; Til, A.E. van

1994-10-01T23:59:59.000Z

359

High temperature catalytic membrane reactors  

DOE Green Energy (OSTI)

Current state-of-the-art inorganic oxide membranes offer the potential of being modified to yield catalytic properties. The resulting modules may be configured to simultaneously induce catalytic reactions with product concentration and separation in a single processing step. Processes utilizing such catalytically active membrane reactors have the potential for dramatically increasing yield reactions which are currently limited by either thermodynamic equilibria, product inhibition, or kinetic selectivity. Examples of commercial interest include hydrogenation, dehydrogenation, partial and selective oxidation, hydrations, hydrocarbon cracking, olefin metathesis, hydroformylation, and olefin polymerization. A large portion of the most significant reactions fall into the category of high temperature, gas phase chemical and petrochemical processes. Microporous oxide membranes are well suited for these applications. A program is proposed to investigate selected model reactions of commercial interest (i.e. dehydrogenation of ethylbenzene to styrene and dehydrogenation of butane to butadiene) using a high temperature catalytic membrane reactor. Membranes will be developed, reaction dynamics characterized, and production processes developed, culminating in laboratory-scale demonstration of technical and economic feasibility. As a result, the anticipated increased yield per reactor pass economic incentives are envisioned. First, a large decrease in the temperature required to obtain high yield should be possible because of the reduced driving force requirement. Significantly higher conversion per pass implies a reduced recycle ratio, as well as reduced reactor size. Both factors result in reduced capital costs, as well as savings in cost of reactants and energy.

Not Available

1990-03-01T23:59:59.000Z

360

The tripartite type III secreton of Shigella flexneri inserts IpaB and IpaC into host membranes  

E-Print Network (OSTI)

Abstract. Bacterial type III secretion systems serve to translocate proteins into eukaryotic cells, requiring a secreton and a translocator for proteins to pass the bacterial and host membranes. We used the contact hemolytic activity of Shigella flexneri to investigate its putative translocator. Hemolysis was caused by formation of a 25-Å pore within the red blood cell (RBC) membrane. Of the five proteins secreted by Shigella upon activation of its type III secretion system, only the hydrophobic IpaB and IpaC were tightly associated with RBC membranes isolated after hemolysis. Ipa protein secretion and hemolysis were kinetically coupled processes. However, Ipa protein secretion in the immediate vicinity of RBCs was not sufficient to cause hemolysis in the absence of centrifugation. Centrifugation

Ariel Blocker; Pierre Gounon; Eric Larquet; Kirsten Niebuhr; Véronique Cabiaux; Claude Parsot

1999-01-01T23:59:59.000Z

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361

Membrane Characterization for a Sulfur- Dioxide Depolarized ...  

with hot H 2SO 4 solution SO 2 transport under non-polarized conditions Ionic conductivity ... 2 transport characterization cell SO 2 Transport ...

362

Hydrogen separation membranes annual report for FY 2008.  

DOE Green Energy (OSTI)

The objective of this work is to develop dense ceramic membranes for separating hydrogen from other gaseous components in a nongalvanic mode, i.e., without using an external power supply or electrical circuitry. The goal of this project is to develop dense hydrogen transport membranes (HTMs) that nongalvanically (i.e., without electrodes or external power supply) separate hydrogen from gas mixtures at commercially significant fluxes under industrially relevant operating conditions. HTMs will be used to separate hydrogen from gas mixtures such as the product streams from coal gasification, methane partial oxidation, and water-gas shift reactions. Potential ancillary uses of HTMs include dehydrogenation and olefin production, as well as hydrogen recovery in petroleum refineries and ammonia synthesis plants, the largest current users of deliberately produced hydrogen. This report describes progress that was made during Fy 2008 on the development of HTM materials.

Balachandran, U.; Dorris, S. E.; Emerson, J. E.; Lee, T. H.; Lu, Y.; Park, C. Y.; Picciolo, J. J.; Energy Systems

2009-03-17T23:59:59.000Z

363

Dense ceramic membranes for converting methane to syngas  

DOE Green Energy (OSTI)

Dense mixed-oxide ceramics capable of conducting both electrons and oxygen ions are promising materials for partial oxygenation of methane to syngas. We are particularly interested in an oxide based on the Sr-Fe-Co-O system. Dense ceramic membrane tubes have been fabricated by a plastic extrusion technique. The sintered tubes were then used to selectively transport oxygen from air through the membrane to make syngas without the use of external electrodes. The sintered tubes have operated for >1000 h, and methane conversion efficiencies of >98% have been observed. Mechanical properties, structural integrity of the tubes during reactor operation, results of methane conversion, selectivity of methane conversion products, oxygen permeation, and fabrication of multichannel configurations for large-scale production of syngas will be presented.

Balachandran, U.; Dusek, J.T.; Picciolo, J.J.; Ma, B.; Maiya, P.S.; Mieville, R.L. [Argonne National Lab., IL (United States); Kleefisch, M.S.; Udovich, C.A. [Amoco Exploration/Production, Naperville, IL (United States)

1995-07-01T23:59:59.000Z

364

Hydrogen separation membranes annual report for FY 2009.  

SciTech Connect

The objective of this work is to develop dense ceramic membranes for separating hydrogen from other gaseous components in a nongalvanic mode, i.e., without using an external power supply or electrical circuitry. The goal of this project is to develop dense hydrogen transport membranes (HTMs) that nongalvanically (i.e., without electrodes or external power supply) separate hydrogen from gas mixtures at commercially significant fluxes under industrially relevant operating conditions. HTMs will be used to separate hydrogen from gas mixtures such as the product streams from coal gasification, methane partial oxidation, and water-gas shift reactions. Potential ancillary uses of HTMs include dehydrogenation and olefin production, as well as hydrogen recovery in petroleum refineries and ammonia synthesis plants, the largest current users of deliberately produced hydrogen. This report describes the results from the development and testing of HTM materials during FY 2009.

Balachandran, U.; Dorris, S. E.; Lu, Y.; Emerson, J. E.; Park, C. Y.; Lee, T. H.; Picciolo, J. J.; Energy Systems

2010-04-16T23:59:59.000Z

365

Development of mixed-conducting ceramic membranes for hydrogen separation.  

DOE Green Energy (OSTI)

SrCeO{sub 3}- and BaCeO{sub 3}-based proton conductors have been prepared and their transport properties have been investigated by impedance spectroscopy in conjunction with open circuit voltage and water vapor evolution measurements. BaCe{sub 0.8}Y{sub 0.2}O{sub 3-{delta}} exhibits the highest conductivity in a hydrogen-containing atmosphere; however, its electronic conductivity is not adequate for hydrogen separation in a nongalvanic mode. In an effort to enhance ambipolar conductivity and improve interfacial catalytic properties, BaCe{sub 0.8}Y{sub 0.2}O{sub 3-{delta}} cermets have been fabricated into membranes. The effects of ambipolar conductivity, membrane thickness, and interfacial resistance on permeation rates have been investigated. In particular, the significance of interfacial resistance is emphasized.

Guan, J.

1998-05-18T23:59:59.000Z

366

The Path a Proton Takes Through a Fuel Cell Membrane  

NLE Websites -- All DOE Office Websites (Extended Search)

Path a Proton Path a Proton Takes Through a Fuel Cell Membrane The Path a Proton Takes Through a Fuel Cell Membrane October 11, 2012 | Tags: Basic Energy Sciences (BES), Chemistry, Franklin, Hopper Linda Vu, lvu@lbl.gov, +1 510 495 2402 Ram.jpg The cover represents the environment around the side chain. The right side is the water network that exists between the sulfonate groups shown in yellow. The left side is the short chain with the sulfonate group. Many experts believe that fuel cells may someday serve as revolutionary clean energy conversion devices for transportation and other portable power applications. Because they generate electricity by converting chemical hydrogen and oxygen into water, fuel cells generate energy much more efficiently than combustion devices, and with near-zero pollutant

367

Durable, Low Cost, Improved Fuel Cell Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

Durable, Low-cost, Improved Durable, Low-cost, Improved Fuel Cell Membranes US Department of Energy Office of Hydrogen, Fuel Cells and Infrastructure Technologies Kickoff Meeting, Washington DC, February 13, 2007 Michel Fouré Project Objectives z To develop a low cost (vs. perfluorosulfonated ionomers), durable membrane. z To develop a membrane capable at 80°C at low relative humidity (25-50%). z To develop a membrane capable of operating at 120°C for brief periods of time. z To elucidate membrane degradation and failure mechanisms. U:jen/slides/pres.07/FC kickoff Washington DC 2-13-07 2 Technical Barriers Addressed z Membrane Cost z Membrane Durability z Membrane capability to operate at low relative humidity. z Membrane capability to operate at 120ºC for brief period of times.

368

High Temperature Membrane & Advanced Cathode Catalyst Development  

DOE Green Energy (OSTI)

Current project consisted of three main phases and eighteen milestones. Short description of each phase is given below. Table 1 lists program milestones. Phase 1--High Temperature Membrane and Advanced Catalyst Development. New polymers and advanced cathode catalysts were synthesized. The membranes and the catalysts were characterized and compared against specifications that are based on DOE program requirements. The best-in-class membranes and catalysts were downselected for phase 2. Phase 2--Catalyst Coated Membrane (CCM) Fabrication and Testing. Laboratory scale catalyst coated membranes (CCMs) were fabricated and tested using the down-selected membranes and catalysts. The catalysts and high temperature membrane CCMs were tested and optimized. Phase 3--Multi-cell stack fabrication. Full-size CCMs with the down-selected and optimized high temperature membrane and catalyst were fabricated. The catalyst membrane assemblies were tested in full size cells and multi-cell stack.

Protsailo, Lesia

2006-04-20T23:59:59.000Z

369

Continuous production of polymethylpentene membranes  

DOE Patents (OSTI)

Gas separation membranes may be prepared in a continuous manner by passing a porous support which may, if so desired, be backed by a fabric through a solution of polymethylpentene dissolved in an organic solvent such as hexane. The support member is passed through the solution while one side thereof is in contact with a roller, thereby permitting only one side of the support member to be coated with the polymer. After continuously withdrawing the support member from the bath, the solvent is allowed to evaporate and the resulting membrane is recovered.

Epperson, B.J.; Burnett, L.J.; Helm, V.D.

1983-11-15T23:59:59.000Z

370

ASU nitrogen sweep gas in hydrogen separation membrane for production of HRSG duct burner fuel  

DOE Patents (OSTI)

The present invention relates to the use of low pressure N2 from an air separation unit (ASU) for use as a sweep gas in a hydrogen transport membrane (HTM) to increase syngas H2 recovery and make a near-atmospheric pressure (less than or equal to about 25 psia) fuel for supplemental firing in the heat recovery steam generator (HRSG) duct burner.

Panuccio, Gregory J.; Raybold, Troy M.; Jamal, Agil; Drnevich, Raymond Francis

2013-04-02T23:59:59.000Z

371

State-of-the-Art Assessment of Polymer Electrolyte Membrane Fuel Cells for Distributed Power Applications  

Science Conference Proceedings (OSTI)

Low-temperature polymer electrolyte membrane fuel cell technology targeted for transportation markets has been rapidly advancing the past few years. This technology represents a potentially strategic retail access technology that could be useful in a variety of utility, commercial, and residential distributed power and retail energy service applications.

1997-01-08T23:59:59.000Z

372

High flux ceramic membrane for hydrogen separation. Final technical progress report  

DOE Green Energy (OSTI)

Fuel cells that convert hydrogen to electricity will play an increasingly important role in the generation of future electric power for stationary and transportation sector applications. However, more economic methods to produce hydrogen from fossil fuels are needed. This project addresses the need to develop low cost ceramic membranes for hydrogen separation from reformed fuels.

K. Durai-Swamy

1999-05-04T23:59:59.000Z

373

Electrolytic process to produce sodium hypochlorite using sodium ion conductive ceramic membranes  

SciTech Connect

An electrochemical process for the production of sodium hypochlorite is disclosed. The process may potentially be used to produce sodium hypochlorite from seawater or low purity un-softened or NaCl-based salt solutions. The process utilizes a sodium ion conductive ceramic membrane, such as membranes based on NASICON-type materials, in an electrolytic cell. In the process, water is reduced at a cathode to form hydroxyl ions and hydrogen gas. Chloride ions from a sodium chloride solution are oxidized in the anolyte compartment to produce chlorine gas which reacts with water to produce hypochlorous and hydrochloric acid. Sodium ions are transported from the anolyte compartment to the catholyte compartment across the sodium ion conductive ceramic membrane. Sodium hydroxide is transported from the catholyte compartment to the anolyte compartment to produce sodium hypochlorite within the anolyte compartment.

Balagopal, Shekar; Malhotra, Vinod; Pendleton, Justin; Reid, Kathy Jo

2012-09-18T23:59:59.000Z

374

Transportation Applications  

DOE Green Energy (OSTI)

The purpose of this project is to systematically identify and examine possible near and long-term ecological and environmental effects from the production of hydrogen from various energy sources based on the DOE hydrogen production strategy and the use of that hydrogen in transportation applications. This project uses state-of-the-art numerical modeling tools of the environment and energy system emissions in combination with relevant new and prior measurements and other analyses to assess the understanding of the potential ecological and environmental impacts from hydrogen market penetration. H2 technology options and market penetration scenarios will be evaluated using energy-technology-economics models as well as atmospheric trace gas projections based on the IPCC SRES scenarios including the decline in halocarbons due to the Montreal Protocol. Specifically we investigate the impact of hydrogen releases on the oxidative capacity of the atmosphere, the long-term stability of the ozone layer due to changes in hydrogen emissions, the impact of hydrogen emissions and resulting concentrations on climate, the impact on microbial ecosystems involved in hydrogen uptake, and criteria pollutants emitted from distributed and centralized hydrogen production pathways and their impacts on human health, air quality, ecosystems, and structures under different penetration scenarios

Wuebbles, D.J.; Dubey, M.K., Edmonds, J.; Layzell, D.; Olsen, S.; Rahn, T.; Rocket, A.; Wang, D.; Jia, W.

2010-06-01T23:59:59.000Z

375

Mixed hydrocarbon/fluoropolymer membrane/ionomer MEAs for durability studies  

SciTech Connect

The durability of polymer electrolyte membrane (PEM) fuel cells is a major barrier to the commercialization of these systems for stationary and transportation power applications. Commercial viability depends on improving the durability of the fuel cell components to increase the system reliability. The aim of this work is to separate ionomer degradation from membrane degradation via mixed membrane/ionomer MEA experiments. The challenges of mixed MEA fabrication due to the incompatibility of the membrane and the electrode are addressed. OCV accelerated testing experiment (AST) were performed. Development of in situ diagnostics and unique experiments to characterize the performance and properties of the ionomer in the electrode as a function of time is reported. These measurements, along with extensive ex situ and post-mortem characterization, can delineate the degradation mechanisms in order to develop more durable fuel cells and fuel cell components.

Li, Bo [Los Alamos National Laboratory; Kim, Yu Seung [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Borup, Rodney L [Los Alamos National Laboratory; Wilson, Mahlon S [Los Alamos National Laboratory; Welch, Cynthia [Los Alamos National Laboratory; Fenton, James [FLORIDA SOLAR ENERGY CENTER

2010-01-01T23:59:59.000Z

376

Design and demonstration of a high-temperature, deployable, membrane heat-pipe radiator element  

SciTech Connect

Demonstration of a high-temperature, deployable, membrane heat-pipe radiator element has been conducted. Membrane heat pipes offer the potential for compact storage, ease of transportation, self-deployment, and a high specific radiator performance (kg/kW) for use in thermal reflection systems of space nuclear power plants. A demonstration heat pipe 8-cm wide and 100-cm long was fabricated. The heat pipe containment and wick structure were made of stainless steel and sodium used as the working fluid. The tests demonstrated passive deployment of the high-temperature membrane radiator, simulating a single segment in a flat array, at a temperature of 800 K. Details of test procedures and results of the tests are presented in this paper together with a discussion of the design and development of a full-scale, segmented high-temperature, deployable membrane heat pipe. 5 refs., 7 figs.

Trujillo, V.L.; Keddy, E.S.; Merrigan, M.A.

1989-01-01T23:59:59.000Z

377

SiC-BASED HYDROGEN SELECTIVE MEMBRANES FOR WATER-GAS-SHIFT REACTION  

DOE Green Energy (OSTI)

This technical report summarizes our activities conducted in Yr II. In Yr I we successfully demonstrated the feasibility of preparing the hydrogen selective SiC membrane with a chemical vapor deposition (CVD) technique. In addition, a SiC macroporous membrane was fabricated as a substrate candidate for the proposed SiC membrane. In Yr II we have focused on the development of a microporous SiC membrane as an intermediate layer between the substrate and the final membrane layer prepared from CVD. Powders and supported thin silicon carbide films (membranes) were prepared by a sol-gel technique using silica sol precursors as the source of silicon, and phenolic resin as the source of carbon. The powders and films were prepared by the carbothermal reduction reaction between the silica and the carbon source. The XRD analysis indicates that the powders and films consist of SiC, while the surface area measurement indicates that they contain micropores. SEM and AFM studies of the same films also validate this observation. The powders and membranes were also stable under different corrosive and harsh environments. The effects of these different treatments on the internal surface area, pore size distribution, and transport properties, were studied for both the powders and the membranes using the aforementioned techniques and XPS. Finally the SiC membrane materials are shown to have satisfactory hydrothermal stability for the proposed application. In Yr III, we will focus on the demonstration of the potential benefit using the SiC membrane developed from Yr I and II for the water-gas-shift (WGS) reaction.

Paul K.T. Liu

2001-10-16T23:59:59.000Z

378

Membrane proteomics of phagosomes suggests a connection to autophagy  

SciTech Connect

Phagocytosis is the central process by which macrophage cellsinternalize and eliminate infectious microbes as well as apoptoticcells. During maturation, phagosomes containing engulfed particlesfuse with various endosomal compartments through theaction of regulatory molecules on the phagosomal membrane. Inthis study, we performed a proteomic analysis of the membranefraction from latex bead-containing (LBC) phagosomes isolatedfrom macrophages. The profile, which comprised 546 proteins,suggests diverse functions of the phagosome and potential connectionsto secretory processes, toll-like receptor signaling, andautophagy. Many identified proteins were not previously knownto reside in the phagosome. We characterized several proteins inLBC phagosomes that change in abundance on induction of autophagy,a process that has been previously implicated in the hostdefense against microbial pathogens. These observations suggestcrosstalk between autophagy and phagocytosis that may be relevantto the innate immune response of macrophages.

Shui, Wenqing; Sheu, Leslie; Liu, Jun; Smart, Brian; Petzold, Christopher J.; Hsieh, Tsung-yen; Pitcher, Austin; Keasling*, Jay D.; Bertozzi*, Carolyn R.

2008-11-25T23:59:59.000Z

379

Argonne CNM News: Ultrananocrystalline Diamond-Coated Membranes...  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrananocrystalline Diamond-Coated Membranes Show Promise for Medical Implant Applications SEM image of UNCD coated AAO membrane SEM image of AAO membrane coated with tungsten...

380

Preparation of gas selective membranes  

DOE Patents (OSTI)

Gas separation membranes which possess improved characteristics as exemplified by selectivity and flux may be prepared by coating a porous organic polymer support with a solution or emulsion of a plasticizer and an organic polymer, said coating being effected at subatmospheric pressures in order to increase the penetration depth of the coating material.

Kulprathipanja, S.; Kulkarni, S.S.; Funk, E.W.

1988-06-14T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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.


381

Cathode porous transport irreversibility model for PEM fuel cell design  

Science Conference Proceedings (OSTI)

The influence is studied of slip-irreversibility at the interface between the gas diffusion layer, also referred to here as the porous transport layer, and the catalyst layer of a proton exchange membrane fuel cell (PEMFC). A two-dimensional cathode ... Keywords: catalyst layer, exergy, gas diffusion layer, slip flow irreversibility

E. O. B. Ogedengbe; M. A. Rosen

2009-02-01T23:59:59.000Z

382

Ceramic membrane reactor with two reactant gases at different pressures  

DOE Patents (OSTI)

The invention is a ceramic membrane reactor for syngas production having a reaction chamber, an inlet in the reactor for natural gas intake, a plurality of oxygen permeating ceramic slabs inside the reaction chamber with each slab having a plurality of passages paralleling the gas flow for transporting air through the reaction chamber, a manifold affixed to one end of the reaction chamber for intake of air connected to the slabs, a second manifold affixed to the reactor for removing the oxygen depleted air, and an outlet in the reaction chamber for removing syngas.

Balachandran, Uthamalingam (Hinsdale, IL); Mieville, Rodney L. (Glen Ellyn, IL)

2001-01-01T23:59:59.000Z

383

Transportation Security | ornl.gov  

NLE Websites -- All DOE Office Websites (Extended Search)

Transportation Security SHARE Global Threat Reduction Initiative Transportation Security Cooperation Secure Transport Operations (STOP) Box Security of radioactive material while...

384

Erosion and Optimal Transport  

E-Print Network (OSTI)

383 pp. EROSION AND OPTIMAL TRANSPORT [23] I. Ekeland and T.and D. Simons, Sediment transport capacity of overland ?ow,measure spaces via optimal transport, Ann. of Math. (2),

Birnir, Bjorn; Rowlett, Julie

2010-01-01T23:59:59.000Z

385

Corrugated Membrane Fuel Cell Structures  

SciTech Connect

One of the most challenging aspects of traditional PEM fuel cell stacks is the difficulty achieving the platinum catalyst utilization target of 0.2 gPt/kWe set forth by the DOE. Good catalyst utilization can be achieved with state-of-the-art catalyst coated membranes (CCM) when low catalyst loadings (<0.3 mg/cm2) are used at a low current. However, when low platinum loadings are used, the peak power density is lower than conventional loadings, requiring a larger total active area and a larger bipolar plate. This results in a lower overall stack power density not meeting the DOE target. By corrugating the fuel cell membrane electrode structure, Ion Power?s goal is to realize both the Pt utilization targets as well as the power density targets of the DOE. This will be achieved by demonstrating a fuel cell single cell (50 cm2) with a twofold increase in the membrane active area over the geometric area of the cell by corrugating the MEA structure. The corrugating structure must be able to demonstrate the target properties of < 10 mOhm-cm2 electrical resistance at > 20 psi compressive strength over the active area, in combination with offering at least 80% of power density that can be achieved by using the same MEA in a flat plate structure. Corrugated membrane fuel cell structures also have the potential to meet DOE power density targets by essentially packaging more membrane area into the same fuel cell volume as compared to conventional stack constructions.

Grot, Stephen [President, Ion Power Inc.] President, Ion Power Inc.

2013-09-30T23:59:59.000Z

386

Development of energy efficient membrane distillation systems  

E-Print Network (OSTI)

Membrane distillation (MD) has shown potential as a means of desalination and water purification. As a thermally driven membrane technology which runs at relatively low pressure, which can withstand high salinity feed ...

Summers, Edward K

2013-01-01T23:59:59.000Z

387

Anion permselective membrane. [For redox fuel cells  

DOE Green Energy (OSTI)

Experimental anion permeselective membranes were improved and characterized for use as separators in a chemical redox, power storage cell being developed at the NASA Lewis Research Center. The goal of minimal Fe/sup +3/ ion transfer was achieved for each candidate membrane system. Minimal membrane resistivity was demonstrated by reduction of film thickness using synthetic backing materials but usefulness of thin membranes was limited by the scarcity of compatible fabrics. The most durable and useful backing fabrics were modacrylics. One membrane, a copolymer of 4 vinylpyridine and vinyl benzylchloride was outstanding in overall electrochemical and physical properties. Long term (1000 hrs) membrane chemical and thermal durability in redox environment was shown by three candidate polymers and two membranes. The remainder had good durability at ambient temperature. Manufacturing capability was demonstrated for large scale production of membrane sheets 5.5 ft/sup 2/ in area for two candidate systems.

Alexander, S.S.; Hodgdon, R.B.

1978-01-01T23:59:59.000Z

388

Tetrakis-amido high flux membranes  

DOE Patents (OSTI)

Composite RO membranes of a microporous polymeric support and a polyamide reaction product of a tetrakis-aminomethyl compound and a polyacylhalide are disclosed, said membranes exhibiting high flux and good chlorine resistance.

McCray, Scott B. (Bend, OR)

1989-01-01T23:59:59.000Z

389

Engineering supported membranes for cell biology  

E-Print Network (OSTI)

membranes in structural biology. J Struct Biol 168:1–2 50.supported membranes for cell biology Cheng-han Yu • Jay T.range problems in cell biology. Because lateral mobility of

Yu, Cheng-han; Groves, Jay T.

2010-01-01T23:59:59.000Z

390

Tetrakis-amido high flux membranes  

DOE Patents (OSTI)

Composite RO membranes of a microporous polymeric support and a polyamide reaction product of a tetrakis-aminomethyl compound and a polyacylhalide are disclosed, said membranes exhibiting high flux and good chlorine resistance.

McCray, S.B.

1989-10-24T23:59:59.000Z

391

Transportation Market Distortions  

E-Print Network (OSTI)

Transport Prices and Markets, Victoria Transport PolicySurvey: Survey Suggests Market-Based Vision of Smart Growth,G. 1996. Roads in a Market Economy, Avebury (Aldershot).

Litman, Todd

2006-01-01T23:59:59.000Z

392

Transportation Demand This  

Annual Energy Outlook 2012 (EIA)

69 U.S. Energy Information Administration | Assumptions to the Annual Energy Outlook 2012 Transportation Demand Module The NEMS Transportation Demand Module estimates...

393

Transportation / Field Trips  

Science Conference Proceedings (OSTI)

... In the event that a child misses the transportation, parents may choose the ... their child's class on an outing and possibly transport themselves or their ...

2010-10-05T23:59:59.000Z

394

PBA Transportation Websites  

NLE Websites -- All DOE Office Websites (Extended Search)

Useful Websites for Transportation from PBA From: Patterson, Philip (DOE HQ) Subject: Useful Websites for Transportation from PBA Here are some websites you might want to check...

395

Sustainability and Transport  

E-Print Network (OSTI)

2005. Integrating Sustainability into the Trans- portationTHOUGHT PIECE Sustainability and Transport by Richardof the concept of sustainability to transport planning. In

Gilbert, Richard

2006-01-01T23:59:59.000Z

396

Inorganic dual-layer microporous supported membranes  

SciTech Connect

The present invention provides for a dual-layer inorganic microporous membrane capable of molecular sieving, and methods for production of the membranes. The inorganic microporous supported membrane includes a porous substrate which supports a first inorganic porous membrane having an average pore size of less than about 25 .ANG. and a second inorganic porous membrane coating the first inorganic membrane having an average pore size of less than about 6 .ANG.. The dual-layered membrane is produced by contacting the porous substrate with a surfactant-template polymeric sol, resulting in a surfactant sol coated membrane support. The surfactant sol coated membrane support is dried, producing a surfactant-templated polymer-coated substrate which is calcined to produce an intermediate layer surfactant-templated membrane. The intermediate layer surfactant-templated membrane is then contacted with a second polymeric sol producing a polymeric sol coated substrate which is dried producing an inorganic polymeric coated substrate. The inorganic polymeric coated substrate is then calcined producing an inorganic dual-layered microporous supported membrane in accordance with the present invention.

Brinker, C. Jeffrey (14 Eagle Nest Dr. NE., Albuquerque, NM 87122); Tsai, Chung-Yi (6 Mount Vernon Dr., Apt. C, Vernon, CT 06066); Lu, Yungfeng (1055 N. Capital Ave., #20, San Jose, CA 95133)

2003-03-25T23:59:59.000Z

397

Cellular membrane trafficking of mesoporous silica nanoparticles  

Science Conference Proceedings (OSTI)

This dissertation mainly focuses on the investigation of the cellular membrane trafficking of mesoporous silica nanoparticles. We are interested in the study of endocytosis and exocytosis behaviors of mesoporous silica nanoparticles with desired surface functionality. The relationship between mesoporous silica nanoparticles and membrane trafficking of cells, either cancerous cells or normal cells was examined. Since mesoporous silica nanoparticles were applied in many drug delivery cases, the endocytotic efficiency of mesoporous silica nanoparticles needs to be investigated in more details in order to design the cellular drug delivery system in the controlled way. It is well known that cells can engulf some molecules outside of the cells through a receptor-ligand associated endocytosis. We are interested to determine if those biomolecules binding to cell surface receptors can be utilized on mesoporous silica nanoparticle materials to improve the uptake efficiency or govern the mechanism of endocytosis of mesoporous silica nanoparticles. Arginine-glycine-aspartate (RGD) is a small peptide recognized by cell integrin receptors and it was reported that avidin internalization was highly promoted by tumor lectin. Both RGD and avidin were linked to the surface of mesoporous silica nanoparticle materials to investigate the effect of receptor-associated biomolecule on cellular endocytosis efficiency. The effect of ligand types, ligand conformation and ligand density were discussed in Chapter 2 and 3. Furthermore, the exocytosis of mesoporous silica nanoparticles is very attractive for biological applications. The cellular protein sequestration study of mesoporous silica nanoparticles was examined for further information of the intracellular pathway of endocytosed mesoporous silica nanoparticle materials. The surface functionality of mesoporous silica nanoparticle materials demonstrated selectivity among the materials and cancer and normal cell lines. We aimed to determine the specific organelle that mesoporous silica nanoparticles could approach via the identification of harvested proteins from exocytosis process. Based on the study of endo- and exocytosis behavior of mesoporous silica nanoparticle materials, we can design smarter drug delivery vehicles for cancer therapy that can be effectively controlled. The destination, uptake efficiency and the cellular distribution of mesoporous silica nanoparticle materials can be programmable. As a result, release mechanism and release rate of drug delivery systems can be a well-controlled process. The deep investigation of an endo- and exocytosis study of mesoporous silica nanoparticle materials promotes the development of drug delivery applications.

Fang, I-Ju

2012-06-21T23:59:59.000Z

398

Distinct constrictive processes, separated in time and space,divide Caulobacter inner and outer membranes  

Science Conference Proceedings (OSTI)

Cryo-electron microscope tomography (cryoEM) and a fluorescence loss in photobleaching (FLIP) assay were used to characterize progression of the terminal stages of Caulobacter crescentus cell division. Tomographic cryoEM images of the cell division site show separate constrictive processes closing first the inner, and then the outer, membrane in a manner distinctly different from septum-forming bacteria. The smallest observed pre-fission constrictions were 60 nm for both the inner and outer membrane. FLIP experiments had previously shown cytoplasmic compartmentalization, when cytoplasmic proteins can no longer diffuse between the two nascent progeny cell compartments, occurring 18 min before daughter cell separation in a 135 min cell cycle. Here, we used FLIP experiments with membrane-bound and periplasmic fluorescent proteins to show that (1) periplasmic compartmentalization occurs after cytoplasmic compartmentalization, consistent with the cryoEM observations, and (2) inner membrane and periplasmic proteins can diffuse past the FtsZ constriction site, indicating that the cell division machinery does not block membrane diffusion.

Judd, Ellen M.; Comolli, Luis R.; Chen, Joseph C.; Downing,Kenneth H.; Moerner, W.E.; McAdams, Harley H.

2005-05-01T23:59:59.000Z

399

Bio-Membrane Flexibility Studied in the Presence of ...  

Science Conference Proceedings (OSTI)

Bio-Membrane Flexibility Studied in the Presence of Cholesterol and Salt. Living cell membranes are made of phospholipids ...

400

Durable Fuel Cell Membrane Electrode Assembly (MEA) - Energy ...  

Technology Marketing Summary The membrane electrode assembly (MEA) is an essential, yet highly expensive component of any polymer electrolyte membrane ...

Note: This page contains sample records for the topic "membrane transport proteins" 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

Separation of metals by supported liquid membrane  

DOE Patents (OSTI)

A supported liquid membrane system for the separation of a preselected chemical species within a feedstream, preferably an aqueous feedstream, includes a feed compartment containing a feed solution having at least one preselected chemical species therein, a stripping compartment containing a stripping solution therein, and a microporous polybenzimidazole membrane situated between the compartments, the microporous polybenzimidazole membrane containing an extractant mixture selective for the preselected chemical species within the membrane pores is disclosed along with a method of separating preselected chemical species from a feedstream with such a system, and a supported liquid membrane for use in such a system.

Takigawa, Doreen Y. (Los Alamos, NM)

1992-01-01T23:59:59.000Z

402

Separation of metals by supported liquid membranes  

DOE Patents (OSTI)

A supported liquid membrane system for the separation of a preselected chemical species within a feedstream, preferably an aqueous feedstream, includes a feed compartment containing a feed solution having at least one preselected chemical species therein, a stripping compartment containing a stripping solution therein, and a microporous polybenzimidazole membrane situated between the compartments, the microporous polybenzimidazole membrane containing an extractant mixture selective for the preselected chemical species within the membrane pores is disclosed along with a method of separating preselected chemical species from a feedstream with such a system, and a supported liquid membrane for use in such a system.

Takigawa, D.Y.

1990-12-31T23:59:59.000Z

403

Process for restoring membrane permeation properties  

DOE Patents (OSTI)

A process for restoring the selectivity of high-flee-volume, glassy polymer membranes for condensable components over less-condensable components or non-condensable components of a gas mixture. The process involves exposing the membrane to suitable sorbent vapor, such as propane or butane, thereby reopening the microvoids that make up the free volume. The selectivity of an aged membrane may be restored to 70-100% of its original value. The selectivity of a membrane which is known to age over time can also be maintained by keeping the membrane in a vapor environment when it is not in use.

Pinnau, Ingo (Palo Alto, CA); Toy, Lora G. (San Francisco, CA); Casillas, Carlos G. (San Jose, CA)

1997-05-20T23:59:59.000Z

404

Process for restoring membrane permeation properties  

DOE Patents (OSTI)

A process is described for restoring the selectivity of high-free-volume, glassy polymer membranes for condensable components over less-condensable components or non-condensable components of a gas mixture. The process involves exposing the membrane to suitable sorbent vapor, such as propane or butane, thereby reopening the microvoids that make up the free volume. The selectivity of an aged membrane may be restored to 70--100% of its original value. The selectivity of a membrane which is known to age over time can also be maintained by keeping the membrane in a vapor environment when it is not in use. 8 figs.

Pinnau, I.; Toy, L.G.; Casillas, C.G.

1997-05-20T23:59:59.000Z

405

Hydrogen Selective Exfoliated Zeolite Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydrogen Selective Exfoliated Zeolite Hydrogen Selective Exfoliated Zeolite Membranes Background An important component of the Department of Energy (DOE) Carbon Sequestration Program is the development of carbon capture technologies for power systems. Capturing carbon dioxide (CO 2 ) from mixed-gas streams is a first and critical step in carbon sequestration. To be technically and economically viable, a successful separation method must be applicable to industrially relevant gas streams at realistic

406

Hybrid Solvent-Membrane CO2 Capture: A Solvent/Membrane Hybrid Post-combustion CO2 Capture Process for Existing Coal-Fired Power Plants  

SciTech Connect

IMPACCT Project: The University of Kentucky is developing a hybrid approach to capturing CO2 from the exhaust gas of coal-fired power plants. In the first, CO2 is removed as flue gas is passed through an aqueous ammonium-based solvent. In the second, carbon-rich solution from the CO2 absorber is passed through a membrane that is designed to selectively transport the bound carbon, enhancing its concentration on the permeate side. The team’s approach would combine the best of both membrane- and solventbased carbon capture technologies. Under the ARPA-E award, the team is enabling the membrane operation to be a drop-in solution.

None

2010-07-01T23:59:59.000Z

407

Separation of Dimethyl Ether from Syn-Gas Components by Poly(dimethylsiloxane) and Poly(4-methyl-1-pentene) Membranes  

Science Conference Proceedings (OSTI)

Permeability and selectivity in gas transport through poly(4-methyl-1-pentene) (TPX) and poly(dimethylsiloxane) (PDMS) using variable temperature mixed gas experiments is reported. Selected gases include H2, CO, CH4, CO2, and dimethyl ether (DME). The DME data is the first to be reported through these membranes. In this paper, the chosen polymers reflect both rubbery and crystalline materials. Rubbery polymers tend to be weakly size sieving, which, in this work, has resulted in larger permeabilities, lower separation factors, and lower activation energies of permeation (Ep). Conversely, the crystalline TPX membranes showed much greater sensitivity to penetrant size; although the gas condensability also played a role in transport.

Christopher J. Orme; Frederick F. Stewart

2011-05-01T23:59:59.000Z

408

Exp1p is a cargo adaptor for Sec24p mediated export the plasma membrane H+? ATPase from the ER in S. cerevisiae  

E-Print Network (OSTI)

The secretory pathway in S. cerevisiae is responsible for the folding, modification and delivery of plasma membrane and secreted proteins. The secretory pathway consists of an ordered series of organelles including the ...

Morse, Darcy L. (Darcy Lee)

2013-01-01T23:59:59.000Z

409

Graduate Certificate in Transportation  

E-Print Network (OSTI)

Graduate Certificate in Transportation Nohad A. Toulan School of Urban Studies and Planning of Engineering and Computer Science integrated transportation systems. The Graduate Certificate in Transportation their capabilities. Students in the program can choose among a wide range of relevant courses in transportation

Bertini, Robert L.

410

TRANSPORTATION Annual Report  

E-Print Network (OSTI)

and educate the future transportation workforce. An example of what we can accomplish is shown2003 CENTER FOR TRANSPORTATION STUDIES Annual Report #12;Center for Transportation Studies University of Minnesota 200 Transportation and Safety Building 511 Washington Avenue S.E. Minneapolis, MN

Minnesota, University of

411

Transportation Organization and Functions  

Energy.gov (U.S. Department of Energy (DOE))

Office of Packaging and Transportation list of organizations and functions, with a list of acronyms.

412

Nucleocytoplasmic transport: a thermodynamic mechanism  

E-Print Network (OSTI)

The nuclear pore supports molecular communication between cytoplasm and nucleus in eukaryotic cells. Selective transport of proteins is mediated by soluble receptors, whose regulation by the small GTPase Ran leads to cargo accumulation in, or depletion from the nucleus, i.e., nuclear import or nuclear export. We consider the operation of this transport system by a combined analytical and experimental approach. Provocative predictions of a simple model were tested using cell-free nuclei reconstituted in Xenopus egg extract, a system well suited to quantitative studies. We found that accumulation capacity is limited, so that introduction of one import cargo leads to egress of another. Clearly, the pore per se does not determine transport directionality. Moreover, different cargo reach a similar ratio of nuclear to cytoplasmic concentration in steady-state. The model shows that this ratio should in fact be independent of the receptor-cargo affinity, though kinetics may be strongly influenced. Numerical conservation of the system components highlights a conflict between the observations and the popular concept of transport cycles. We suggest that chemical partitioning provides a framework to understand the capacity to generate concentration gradients by equilibration of the receptor-cargo intermediary.

R. B. Kopito; M. Elbaum

2009-03-15T23:59:59.000Z

413

NETL: Hydrogen Selective Exfoliated Zeolite Membranes  

NLE Websites -- All DOE Office Websites (Extended Search)

Hydrogen Selective Exfoliated Zeolite Membranes Hydrogen Selective Exfoliated Zeolite Membranes Project No.: DE-FE0001322 The University of Minnesota is developing a technically and economically viable membrane for carbon dioxide (CO2) separation from typical water-gas-shift (WGS) mixture feeds. The goal of this project is to further develop recently developed membrane technology based on exfoliated zeolite coatings as components for carbon capture in integrated gasification combined cycle plants. These membranes have the potential to contribute to carbon capture by high-temperature separation of hydrogen from CO2 and other gases present in shifted synthesis gas. Molecular sieve membrane for the pre-combustion capture of CO2. Molecular sieve membrane for the pre-combustion capture of CO2. Related Papers and Publications:

414

Interaction of arginine oligomer with model membrane  

SciTech Connect

Short oligomers of arginine (R8) have been shown to cross readily a variety of biological barriers. A hypothesis was put forward that inverted micelles form in biological membranes in the presence of arginine oligomer peptides, facilitating their transfer through the membranes. In order to define the role of peptide-lipid interaction in this mechanism, we prepared liposomes as the model membrane to study the ability of R8 inducing calcein release from liposomes, the fusion of liposomes, R8 binding to liposomes and membrane disturbing activity of the bound R8. The results show that R8 binding to liposome membrane depends on lipid compositions, negative surface charge density and interior water phase pH values of liposomes. R8 has no activity to induce the leakage of calcein from liposomes or improve liposome fusion. R8 does not permeabilize through the membrane spontaneously. These peptides delivering drugs through membranes may depend on receptors and energy.

Yi, Dandan [Department of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, No.13, Hangkong Road, Wuhan 430040 (China)]. E-mail: yi_dandan@yahoo.com.cn; Guoming, Li [National Laboratory of Biomacromolecules, Institute of Biophysics, The Chinese Academy of Science, Beijing 100101 (China); Gao, Li [Department of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, No.13, Hangkong Road, Wuhan 430040 (China); Wei, Liang [National Laboratory of Biomacromolecules, Institute of Biophysics, The Chinese Academy of Science, Beijing 100101 (China)

2007-08-10T23:59:59.000Z

415

COMBUSTION-ASSISTED CO2 CAPTURE USING MECC MEMBRANES  

Science Conference Proceedings (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

416

Combustion-Assisted CO2 Capture Using MECC Membranes  

Science Conference Proceedings (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

417

Multi-modal Transportation > Highway Transportation > Trucking > Railroad transportation > Public transit > Rural transportation > Rural transit > Freight pipeline transportation > Airport planning and development > Airport maintenance > Bicycle and pedes  

E-Print Network (OSTI)

Multi-modal Transportation > Highway Transportation > Trucking > Railroad transportation > Public transit > Rural transportation > Rural transit > Freight pipeline transportation > Airport planning and development > Airport maintenance > Bicycle and pedestrian > Ports and waterways >>> Transportation operat

418

Transportation Planning & Decision Science Group Transportation...  

NLE Websites -- All DOE Office Websites (Extended Search)

Award on January 16, 2013, during the Chairman's Luncheon at the 92nd Annual Transportation Research Board (TRB) Meeting in Washington, DC. Dr. Greene was honored for his...

419

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)

Zinc and Health: Current Status and Future Directions Zinc Transport in the Brain: Routes of Zinc and that mediate extracellular zinc toxicity and (3) a plasma membrane transporter potentially present in all of mechanism, is the transporter pathway. The kinetics of zinc uptake in cultured neurons under resting

420

Preparation and characterization of composite membrane for high temperature gas separation  

DOE Green Energy (OSTI)

A new class of perm-selective inorganic membrane was developed by electroless deposition of palladium thin-film on a microporous {alpha}-alumina ceramic substrate ({phi}39 mm x 2 mm thickness, nominal pore size 150 nm and open porosity {approx} 42 %). The new membrane was characterized by Scanning Electron Micrography (SEM), Energy Dispersive X-ray Analysis (EDX) and conducting permeability experiments with hydrogen, helium, argon and carbon dioxide at temperatures from 473 K to 673 K and feed pressures from 136 kPa to 274 kPa. The results indicate that the membrane has both high permeability and selectivity for hydrogen. The hydrogen transport through the Pd-composite membrane closely followed Sievert's law. A theoretical model is presented to describe the performance of a single-stage permeation process. The model uses a unified mathematical formulation and calculation methods for two flow patterns (cocurrent and countercurrent) with two permeable components and a nonpermeable fraction in the feed and a sweep stream in the permeate. The countercurrent flow pattern is always better than the cocurrent flow pattern with respect to stage cut and membrane area. The effect of flow configuration decreases with increasing membrane selectivity or with decreasing permeate/feed ratio.

Ilias, S.; King, F.G.

1998-03-26T23:59:59.000Z

Note: This page contains sample records for the topic "membrane transport proteins" 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

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de Lijser, Peter

422

Quantum dynamics of an optical cavity coupled to a thin semitransparent membrane: Effect of membrane absorption  

Science Conference Proceedings (OSTI)

We study the quantum dynamics of the cavity optomechanical system formed by a Fabry-Perot cavity with a thin vibrating membrane at its center. We determine in particular to what extent optical absorption by the membrane hinders reaching a quantum regime for the cavity-membrane system. We show that even though membrane absorption may significantly lower the cavity finesse and also heat the membrane, one can still simultaneously achieve ground state cooling of a vibrational mode of the membrane and stationary optomechanical entanglement with state-of-the-art apparatuses.