X-ray beamsplitter

DOEpatents

Ceglio, Natale M.; Stearns, Daniel S.; Hawryluk, Andrew M.; Barbee, Jr., Troy W.

1989-01-01

An x-ray beamsplitter which splits an x-ray beam into two coherent parts by reflecting and transmitting some fraction of an incident beam has applications for x-ray interferometry, x-ray holography, x-ray beam manipulation, and x-ray laser cavity output couplers. The beamsplitter is formed of a wavelength selective multilayer thin film supported by a very thin x-ray transparent membrane. The beamsplitter resonantly transmits and reflects x-rays through thin film interference effects. A thin film is formed of 5-50 pairs of alternate Mo/Si layers with a period of 20-250 A. The support membrane is 10-200 nm of silicon nitride or boron nitride. The multilayer/support membrane structure is formed across a window in a substrate by first forming the structure on a solid substrate and then forming a window in the substrate to leave a free-standing structure over the window.

Structures and fabrication techniques for solid state electrochemical devices

DOEpatents

Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

2006-10-10

Low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures provide solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one aspect the invention provides techniques for co-firing of device substrate (often an electrode) with an electrolyte or membrane layer to form densified electrolyte/membrane films 5 to 20 microns thick. In another aspect, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe and Cu, or alloys thereof.

Ultra-Thin Solid-State Nanopores: Fabrication and Applications

NASA Astrophysics Data System (ADS)

Kuan, Aaron Tzeyang

Solid-state nanopores are a nanofluidic platform with unique advantages for single-molecule analysis and filtration applications. However, significant improvements in device performance and scalable fabrication methods are needed to make nanopore devices competitive with existing technologies. This dissertation investigates the potential advantages of ultra-thin nanopores in which the thickness of the membrane is significantly smaller than the nanopore diameter. Novel, scalable fabrication methods were first developed and then utilized to examine device performance for water filtration and single molecule sensing applications. Fabrication of nanometer-thin pores in silicon nitride membranes was achieved using a feedback-controlled ion beam method in which ion sputtering is arrested upon detection of the first few ions that drill through the membrane. Performing fabrication at liquid nitrogen temperatures prevents surface atom rearrangements that have previously complicated similar processes. A novel cross-sectional imaging method was also developed to allow careful examination of the full nanopore geometry. Atomically-thin graphene nanopores were fabricated via an electrical pulse method in which sub-microsecond electrical pulses applied across a graphene membrane in electrolyte solution are used to create a defect in the membrane and controllably enlarge it into a nanopore. This method dramatically increases the accuracy and reliability of graphene nanopore production, allowing consistent production of single nanopores down to subnanometer sizes. In filtration applications in which nanopores are used to selectively restrict the passage of dissolved contaminants, ultra-thin nanopores minimize the flow resistance, increasing throughput and energy-efficiency. The ability of graphene nanopores to separate different ions was characterized via ionic conductance and reversal potential measurements. Graphene nanopores were observed to conduct cations preferentially over anions with selectivity ratios of 100 or higher for pores as large as 20 nm in diameter, suggesting that porous graphene membranes can be used to create highly effective cation exchange membranes for electrodialysis filtration. These surprisingly high selectivities cannot be explained by current models of ionic conduction in graphene nanopores, motivating the development of a new model in which elevated concentrations of mobile cations near the graphene surface generate additional ion selectivity.

Structures And Fabrication Techniques For Solid State Electrochemical Devices

DOEpatents

Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

2005-12-27

Provided are low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures. The invention provides solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one embodiment the invention provides techniques for co-firing of device substrate (often an electrode) with an electrolyte or membrane layer to form densified electrolyte/membrane films 5 to 20 microns thick. In another embodiment, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe, Cu and Ag, or alloys thereof.

Structures and fabrication techniques for solid state electrochemical devices

DOEpatents

Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

2003-08-12

Provided are low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures. The invention provides solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one embodiment the invention provides techniques for co-firing of device substrate (often an electrode) with an electrolyte or membrane layer to form densified electrolyte/membrane films 5 to 20 microns thick. In another embodiment, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe, Cu and Ag, or alloys thereof.

High Temperature Protonic Conductors

NASA Technical Reports Server (NTRS)

Dynys, Fred; Berger, Marie-Helen; Sayir, Ali

2007-01-01

High Temperature Protonic Conductors (HTPC) with the perovskite structure are envisioned for electrochemical membrane applications such as H2 separation, H2 sensors and fuel cells. Successive membrane commercialization is dependent upon addressing issues with H2 permeation rate and environmental stability with CO2 and H2O. HTPC membranes are conventionally fabricated by solid-state sintering. Grain boundaries and the presence of intergranular second phases reduce the proton mobility by orders of magnitude than the bulk crystalline grain. To enhanced protonic mobility, alternative processing routes were evaluated. A laser melt modulation (LMM) process was utilized to fabricate bulk samples, while pulsed laser deposition (PLD) was utilized to fabricate thin film membranes . Sr3Ca(1+x)Nb(2-x)O9 and SrCe(1-x)Y(x)O3 bulk samples were fabricated by LMM. Thin film BaCe(0.85)Y(0.15)O3 membranes were fabricated by PLD on porous substrates. Electron microscopy with chemical mapping was done to characterize the resultant microstructures. High temperature protonic conduction was measured by impedance spectroscopy in wet air or H2 environments. The results demonstrate the advantage of thin film membranes to thick membranes but also reveal the negative impact of defects or nanoscale domains on protonic conductivity.

Numerical analysis of a red blood cell flowing through a thin micropore.

PubMed

Omori, Toshihiro; Hosaka, Haruki; Imai, Yohsuke; Yamaguchi, Takami; Ishikawa, Takuji

2014-01-01

Red blood cell (RBC) deformability plays a key role in microcirculation, especially in vessels that have diameters even smaller than the nominal cell size. In this study, we numerically investigate the dynamics of an RBC in a thin micropore. The RBC is modeled as a capsule with a thin hyperelastic membrane. In a numerical simulation, we employ a boundary element method for fluid mechanics and a finite element method for membrane mechanics. The resulting RBC deformation towards the flow direction is suppressed considerably by increased cytoplasm viscosity, whereas the gap between the cell membrane and solid wall becomes smaller with higher cytoplasm viscosity. We also measure the transit time of the RBC and find that nondimensional transit time increases nonlinearly with respect to the viscosity ratio, whereas it is invariant to the capillary number. In conclusion, cytoplasmic viscosity plays a key role in the dynamics of an RBC in a thin pore. The results of this study will be useful for designing a microfluidic device to measure cytoplasmic viscosity.

Diamond drumhead crystals for X-ray optics applications

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

Kolodziej, Tomasz; Vodnala, Preeti; Terentyev, Sergey

2016-07-14

Thin (<50 µm) and flawless diamond single crystals are essential for the realization of numerous advanced X-ray optical devices at synchrotron radiation and free-electron laser facilities. The fabrication and handling of such ultra-thin components without introducing crystal damage and strain is a challenge. Drumhead crystals, monolithic crystal structures composed of a thin membrane furnished with a surrounding solid collar, are a solution ensuring mechanically stable strain-free mounting of the membranes with efficient thermal transport. Diamond, being one of the hardest and most chemically inert materials, poses significant difficulties in fabrication. Reported here is the successful manufacture of diamond drumhead crystalsmore » in the [100] orientation using picosecond laser milling. Subsequent high-temperature treatment appears to be crucial for the membranes to become defect free and unstrained, as revealed by X-ray topography on examples of drumhead crystals with a 26 µm thick (1 mm in diameter) and a 47 µm thick (1.5 × 2.5 mm) membrane.« less

Performance evaluation of a pilot-scale anaerobic membrane bioreactor (AnMBR) treating ethanol thin stillage.

PubMed

Dereli, R K; Urban, D R; Heffernan, B; Jordan, J A; Ewing, J; Rosenberger, G T; Dunaev, T I

2012-01-01

The ethanol industry has grown rapidly during the past ten years, mainly due to increasing oil prices. However, efficient and cost-effective solutions for treating thin stillage wastewater have still to be developed. The anaerobic membrane bioreactor (AnMBR) technology combines classical anaerobic treatment in a completely-stirred tank reactor (CSTR) with membrane separation. The combination of these two technologies can achieve a superior effluent quality and also increase biogas production compared to conventional anaerobic solutions. A pilot-scale AnMBR treating thin stillage achieved very high treatment efficiencies in terms of chemical oxygen demand (COD) and total suspended solids (TSS) removal (>98%). An average permeate flux of 4.3 L/m2 x h was achieved at relatively low transmembrane pressure (TMP) values (0.1-0.2 bars) with flat-sheet membranes. Experience gained during the pilot-scale studies provides valuable information for scaling up of AnMBRs treating complex and high-strength wastewaters.

Nutrient Recovery from the Dry Grind Process Using Sequential Micro and Ultrafiltration of Thin Stillage

USDA-ARS?s Scientific Manuscript database

The effectiveness of microfiltration (MF) and ultrafiltration (UF) for nutrient recovery from a thin stillage stream was determined. When a stainless steel MF membrane (0.1 um pore size) was used, the content of solids increased from 7.0% to 22.8% with a mean permeate flux rate of 45 L/m**2/h (LMH)...

DNA translocation through graphene nanopores.

PubMed

Merchant, Christopher A; Healy, Ken; Wanunu, Meni; Ray, Vishva; Peterman, Neil; Bartel, John; Fischbein, Michael D; Venta, Kimberly; Luo, Zhengtang; Johnson, A T Charlie; Drndić, Marija

2010-08-11

We report on DNA translocations through nanopores created in graphene membranes. Devices consist of 1-5 nm thick graphene membranes with electron-beam sculpted nanopores from 5 to 10 nm in diameter. Due to the thin nature of the graphene membranes, we observe larger blocked currents than for traditional solid-state nanopores. However, ionic current noise levels are several orders of magnitude larger than those for silicon nitride nanopores. These fluctuations are reduced with the atomic-layer deposition of 5 nm of titanium dioxide over the device. Unlike traditional solid-state nanopore materials that are insulating, graphene is an excellent electrical conductor. Use of graphene as a membrane material opens the door to a new class of nanopore devices in which electronic sensing and control are performed directly at the pore.

Effect of varying solid membrane area of bristled wings on clap and fling aerodynamics in the smallest flying insects

NASA Astrophysics Data System (ADS)

Ford, Mitchell; Kasoju, Vishwa; Santhanakrishnan, Arvind

2017-11-01

The smallest flying insects with body lengths under 1.5 mm, such as thrips, fairyflies, and some parasitoid wasps, show marked morphological preference for wings consisting of a thin solid membrane fringed with long bristles. In particular, thrips have been observed to use clap and fling wing kinematics at chord-based Reynolds numbers of approximately 10. More than 6,000 species of thrips have been documented, among which there is notable morphological diversity in bristled wing design. This study examines the effect of varying the ratio of solid membrane area to total wing area (including bristles) on aerodynamic forces and flow structures generated during clap and fling. Forewing image analysis on 30 species of thrips showed that membrane area ranged from 16%-71% of total wing area. Physical models of bristled wing pairs with ratios of solid membrane area to total wing area ranging from 15%-100% were tested in a dynamically scaled robotic platform mimicking clap and fling kinematics. Decreasing membrane area relative to total wing area resulted in significant decrease in maximum drag coefficient and comparatively smaller reduction in maximum lift coefficient, resulting in higher peak lift to drag ratio. Flow structures visualized using PIV will be presented.

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

Teka, S.; Gaied, A.; Jaballah, N.

Highlights: • Microwave-assisted synthesis of rotaxane based on anthracene and β-cyclodextrin. • Morphological and optical characterization of thin solid film. • Elaboration of impedimetric gold/rotaxane sensor. • Investigation of the membrane sensitivity towards Hg{sup 2+}, Cu{sup 2+} and Pb{sup 2+} cations. - Abstract: An impedimetric sensor based on a new semi-conducting rotaxane has been described for detection of toxic cations. The rotaxane, consists on a π-conjugated material encapsulated into β-cyclodextrin (β-CD); it has been synthesized via the Williamson reaction under microwaves irradiation. The supramolecular structure of the compound was confirmed by NMR and FT-IR spectroscopies. A thin solid film ofmore » the rotaxane was deposited by spin-coating to develop a new electrochemical sensor. The morphological properties of the organic membrane were evaluated using contact angle measurements and atomic force microscopy. The gold/rotaxane/solution interfaces were investigated by electrochemical impedance spectroscopy and the obtained data were fitted using an equivalent electrical circuit. The response of the gold/rotaxane membrane towards Hg{sup 2+}, Cu{sup 2+} and Pb{sup 2+} cations was studied and the results showed a good sensitivity to the mercury cations.« less

Epitaxial thin films

DOEpatents

Hunt, Andrew Tye; Deshpande, Girish; Lin, Wen-Yi; Jan, Tzyy-Jiuan

2006-04-25

Epitatial thin films for use as buffer layers for high temperature superconductors, electrolytes in solid oxide fuel cells (SOFC), gas separation membranes or dielectric material in electronic devices, are disclosed. By using CCVD, CACVD or any other suitable deposition process, epitaxial films having pore-free, ideal grain boundaries, and dense structure can be formed. Several different types of materials are disclosed for use as buffer layers in high temperature superconductors. In addition, the use of epitaxial thin films for electrolytes and electrode formation in SOFCs results in densification for pore-free and ideal gain boundary/interface microstructure. Gas separation membranes for the production of oxygen and hydrogen are also disclosed. These semipermeable membranes are formed by high-quality, dense, gas-tight, pinhole free sub-micro scale layers of mixed-conducting oxides on porous ceramic substrates. Epitaxial thin films as dielectric material in capacitors are also taught herein. Capacitors are utilized according to their capacitance values which are dependent on their physical structure and dielectric permittivity. The epitaxial thin films of the current invention form low-loss dielectric layers with extremely high permittivity. This high permittivity allows for the formation of capacitors that can have their capacitance adjusted by applying a DC bias between their electrodes.

Graphene nanopore devices for DNA sensing.

PubMed

Merchant, Chris A; Drndić, Marija

2012-01-01

We describe here a method for detecting the translocation of individual DNA molecules through nanopores created in graphene membranes. The devices consist of 1-5-nm thick graphene membranes with electron-beam sculpted nanopores from 5 to 10 nm in diameter. Due to the thin nature of the graphene membranes, and the reduced electrical resistance, we observe larger blocked currents than for traditional solid-state nanopores. We also show how ionic current noise levels can be reduced with the atomic-layer deposition of a few nanometers of titanium dioxide over the graphene surface. Unlike traditional solid-state nanopore materials that are insulating, graphene is an excellent electrical conductor, and its use opens the door to a new future class of nanopore devices in which electronic sensing and control is performed directly at the pore.

Basal deposits and drusen in eyes with age-related maculopathy: evidence for solid lipid particles.

PubMed

Curcio, Christine A; Presley, J Brett; Millican, C Leigh; Medeiros, Nancy E

2005-06-01

Neutral lipid, including esterified cholesterol, and apolipoproteins B and E are abundant in basal deposits and drusen of aged and age-related maculopathy (ARM) eyes. The principal component of basal linear deposit (BlinD), a specific ARM lesion, is membranous debris, which if actually derived from membranes cannot account for extracellular neutral lipid. We therefore used a lipid-preserving ultrastructural method to obtain improved images of membranous debris. Maculas from 44 human donors (71-96 yr) were preserved <7.5 hr after death. Blocks were post-fixed in 2% osmium or osmium-tannic acid-paraphenylenediamine (OTAP) to preserve neutral lipid for thin-section transmission electron microscopic (TEM) examination. Solid particles identified by OTAP were considered closest to the in vivo state of extracellular lipids. Micrographs were examined for intermediate forms, with greatest weight given to comparable images from different preparations of same or fellow eyes. Twenty eyes of older adults (12 with ARM including fellows treated with photodynamic and radiation therapies) had adequately preserved extracellular lipid. The exterior surface of membranous debris was thicker and more electron-dense than basal infoldings of retinal pigment epithelium (RPE) cells. By OTAP, individual membranous debris profiles were solid (diameters, 80-200 nm) and formed tracks across or aggregations within basal laminar deposits. Solid particles and/or pools of neutral lipid were visible in BlinD and drusen. When processed to preserve lipid, membranous debris resembles neither membranes of surrounding cells nor vesicles possessing aqueous interiors but rather solid particles. These results are consistent with recent evidence implicating lipoprotein particles of intra-ocular origin as a potential source of neutral lipids, including esterified cholesterol, in the specific lesions of ARM.

Influence of annealing time on pH sensitivity of ZnO sensing membrane for EGFET sensor

NASA Astrophysics Data System (ADS)

Zulkefle, M. A.; Rahman, R. A.; Yusoff, K. A.; Abdullah, W. F. H.; Rusop, M.; Herman, S. H.

2018-05-01

Solid-state materials have becomes essential in recent technological advancements. This study also utilized solid-state material but in form of thin films to sense hydrogen ions in solutions. Fabrication of ZnO thin film was done using sol-gel spin coating technique. In an attempt to increase the pH sensitivity of the produced film, prolonging of annealing time was done. It was found that the increase in annealing time from 15 minutes to 30 minutes had managed to improve the sensitivity by 4.35%. The optimum pH sensitivity and linearity obtained in this study is 50.40 mV/pH and 0.9911 respectively.

Heat transfer fouling characteristics of microfiltered thin stillage from the dry grind process.

PubMed

Arora, Amit; Dien, Bruce S; Belyea, Ronald L; Singh, Vijay; Tumbleson, M E; Rausch, Kent D

2010-08-01

We investigated effects of microfiltration (MF) on heat transfer fouling tendencies of thin stillage. A stainless steel MF membrane (0.1 micron pore size) was used to remove solids from thin stillage. At filtration conditions of 690kPa, the MF process effectively recovered total solids from thin stillage. Thin stillage was concentrated from 7.0% to 22.4% solids with average permeate flux rates of 180+/-30 L/m(2)/h at 75 degrees C. In retentate streams, protein and fat contents were increased from 23.5 and 16.7% db to 27.6 and 31.1% db, respectively, and ash content was reduced from 10.5% to 3.8% db. Removal of solids, protein and fat generated a microfiltration permeate (MFP) that was used as an input stream to the fouling probe system; MFP fouling tendencies were measured. An annular fouling probe was used to measure fouling tendencies of thin stillage from a commercial dry grind facility. When comparing diluted thin stillage (DTS) stream and MFP, a reduction in solids concentration was not the only reason of fouling decrement. Selective removal of protein and fat played an important role in mitigating the fouling. At t=10h, mean fouling rates of MFP were an order of magnitude lower when compared to thin stillage and diluted streams. When maximum probe temperature (200 degrees C) was reached, mean fouling rates for thin stillage, DTS and MFP were 7.1x10(-4), 4.2x10(-4) and 2.6x10(-4) m(2) degrees C/kW/min, respectively. In DTS and MFP, the induction period was prolonged by factors of 4.3 and 9.5, respectively, compared to the induction period for thin stillage fouling. Mean fouling rates were decreased by factors of 2.3 and 23.4 for DTS and MFP, respectively. Fouling of MFP took twice the time to reach a probe temperature of 200 degrees C than did thin stillage (22 h vs 10 h, respectively). A reduction in heat transfer fouling could be achieved by altering process stream composition using microfiltration. Copyright 2010 Elsevier Ltd. All rights reserved.

Fabrication of PVDF-based blend membrane with a thin hydrophilic deposition layer and a network structure supporting layer via the thermally induced phase separation followed by non-solvent induced phase separation process

NASA Astrophysics Data System (ADS)

Wu, Zhiguo; Cui, Zhenyu; Li, Tianyu; Qin, Shuhao; He, Benqiao; Han, Na; Li, Jianxin

2017-10-01

A simple strategy of thermally induced phase separation followed by non-solvent induced phase separation (TIPS-NIPS) is reported to fabricate poly (vinylidene fluoride) (PVDF)-based blend membrane. The dissolved poly (styrene-co-maleic anhydride) (SMA) in diluent prevents the crystallization of PVDF during the cooling process and deposites on the established PVDF matrix in the later extraction. Compared with traditional coating technique, this one-step TIPS-NIPS method can not only fabricate a supporting layer with an interconnected network structure even via solid-liquid phase separation of TIPS, but also form a uniform SMA skin layer approximately as thin as 200 nm via surface deposition of NIPS. Besides the better hydrophilicity, what's interesting is that the BSA rejection ratio increases from 48% to 94% with the increase of SMA, which indicates that the separation performance has improved. This strategy can be conveniently extended to the creation of firmly thin layer, surface functionalization and structure controllability of the membrane.

MEMS-based thin-film fuel cells

DOEpatents

Jankowksi, Alan F.; Morse, Jeffrey D.

2003-10-28

A micro-electro-mechanical systems (MEMS) based thin-film fuel cells for electrical power applications. The MEMS-based fuel cell may be of a solid oxide type (SOFC), a solid polymer type (SPFC), or a proton exchange membrane type (PEMFC), and each fuel cell basically consists of an anode and a cathode separated by an electrolyte layer. Additionally catalyst layers can also separate the electrodes (cathode and anode) from the electrolyte. Gas manifolds are utilized to transport the fuel and oxidant to each cell and provide a path for exhaust gases. The electrical current generated from each cell is drawn away with an interconnect and support structure integrated with the gas manifold. The fuel cells utilize integrated resistive heaters for efficient heating of the materials. By combining MEMS technology with thin-film deposition technology, thin-film fuel cells having microflow channels and full-integrated circuitry can be produced that will lower the operating temperature an will yield an order of magnitude greater power density than the currently known fuel cells.

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

Masuda, Takuya; PRESTO, Japan Science and Technology Agency; Yoshikawa, Hideki

In situ electrochemical X-ray photoelectron spectroscopy (XPS) apparatus, which allows XPS at solid/liquid interfaces under potential control, was constructed utilizing a microcell with an ultra-thin Si membrane, which separates vacuum and a solution. Hard X-rays from a synchrotron source penetrate into the Si membrane surface exposed to the solution. Electrons emitted at the Si/solution interface can pass through the membrane and be analyzed by an analyzer placed in vacuum. Its operation was demonstrated for potential-induced Si oxide growth in water. Effect of potential and time on the thickness of Si and Si oxide layers was quantitatively determined at sub-nanometer resolution.

Slurry spin coating of thin film yttria stabilized zirconia/gadolinia doped ceria bi-layer electrolytes for solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Kim, Hyun Joong; Kim, Manjin; Neoh, Ke Chean; Han, Gwon Deok; Bae, Kiho; Shin, Jong Mok; Kim, Gyu-Tae; Shim, Joon Hyung

2016-09-01

Thin ceramic bi-layered membrane comprising yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC) is fabricated by the cost-effective slurry spin coating technique, and it is evaluated as an electrolyte of solid oxide fuel cells (SOFCs). It is demonstrated that the slurry spin coating method is capable of fabricating porous ceramic films by adjusting the content of ethyl-cellulose binders in the source slurry. The porous GDC layer deposited by spin coating under an optimal condition functions satisfactorily as a cathode-electrolyte interlayer in the test SOFC stack. A 2-μm-thick electrolyte membrane of the spin-coated YSZ/GDC bi-layer is successfully deposited as a dense and stable film directly on a porous NiO-YSZ anode support without any interlayers, and the SOFC produces power output over 200 mW cm-2 at 600 °C, with an open circuit voltage close to 1 V. Electrochemical impedance spectra analysis is conducted to evaluate the performance of the fuel cell components in relation with the microstructure of the spin-coated layers.

A multiphase approach to model ultrafiltration of deformable colloids

NASA Astrophysics Data System (ADS)

Haribabu, Malavika; Dunstan, Dave; Davidson, Malcolm; Harvie, Dalton

2017-11-01

Ultrafiltration (UF) is widely used in the dairy industry to fractionate and concentrate proteins, during the manufacture of milk protein concentrate and cheese. The protein build-up, comprising casein micelles (CM) and whey proteins, at the membrane surface during UF increases the resistance of the membrane system, thereby decreasing the performance of the process unit. CM have a complex structure that hydrodynamically behaves as a hard-sphere when dilute, but deforms beyond the random packing limit, forming a shear-thinning gel. This study employs a mixture model, based on the mixture phase continuity, Navier-Stokes equations, and solids continuity equation, to predict the solid concentration and velocity distribution during UF of CM. Micelle deformation is modelled as a function of volume fraction and dependent on its elastic modulus and particle size. The effect of deformation on gel permeability is implemented via Happel's permeability for hard spheres. Under crossflow conditions, the gel thickness is observed to increase along the membrane length, followed by a decrease towards the end of the membrane, resulting in an increase in flux at the latter section of the membrane. This study demonstrates that the membrane end-effects are important in determining UF performance.

Biomimetic membrane arrays on cast hydrogel supports.

PubMed

Roerdink Lander, Monique; Ibragimova, Sania; Rein, Christian; Vogel, Jörg; Stibius, Karin; Geschke, Oliver; Perry, Mark; Hélix-Nielsen, Claus

2011-06-07

Lipid bilayers are intrinsically fragile and require mechanical support in technical applications based on biomimetic membranes. Tethering the lipid bilayer membranes to solid substrates, either directly through covalent or ionic substrate-lipid links or indirectly on substrate-supported cushions, provides mechanical support but at the cost of small molecule transport through the membrane-support sandwich. To stabilize biomimetic membranes while allowing transport through a membrane-support sandwich, we have investigated the feasibility of using an ethylene tetrafluoroethylene (ETFE)/hydrogel sandwich as the support. The sandwich is realized as a perforated surface-treated ETFE film onto which a hydrogel composite support structure is cast. We report a simple method to prepare arrays of lipid bilayer membranes with low intrinsic electrical conductance on the highly permeable, self-supporting ETFE/hydrogel sandwiches. We demonstrate how the ETFE/hydrogel sandwich support promotes rapid self-thinning of lipid bilayers suitable for hosting membrane-spanning proteins.

Correlation between the ripple phase and stripe domains in membranes.

PubMed

Bernchou, Uffe; Midtiby, Henrik; Ipsen, John Hjort; Simonsen, Adam Cohen

2011-12-01

We investigate the relationship between stripe domains and the ripple phase in membranes. These have previously been observed separately without being linked explicitly. Past results have demonstrated that solid and ripple phases exhibit rich textural patterns related to the orientational order of tilted lipids and the orientation of ripple corrugations. Here we reveal a highly complex network pattern of ripple and solid domains in DLPC, DPPC bilayers with structures covering length scales from 10 nm to 100 μm. Using spincoated double supported membranes we investigate domains by correlated AFM and fluorescence microscopy. Cooling experiments demonstrate the mode of nucleation and growth of stripe domains enriched in the fluorescent probe. Concurrent AFM imaging reveals that these stripe domains have a one-to-one correspondence with a rippled morphology running parallel to the stripe direction. Both thin and thick stripe domains are observed having ripple periods of 13.5±0.2 nm and 27.4±0.6 nm respectively. These are equivalent to previously observed asymmetric/equilibrium and symmetric/metastable ripple phases, respectively. Thin stripes grow from small solid domains and grow predominantly in length with a speed of ~3 times that of the thick stripes. Thick stripes grow by templating on the sides of thinner stripes or can emerge directly from the fluid phase. Bending and branching angles of stripes are in accordance with an underlying six fold lattice. We discuss mechanisms for the nucleation and growth of ripples and discuss a generic phase diagram that may partly rationalize the coexistence of metastable and stable phases. Copyright © 2011 Elsevier B.V. All rights reserved.

A New All Solid State Approach to Gaseous Pollutant Detection

NASA Technical Reports Server (NTRS)

Brown, V.; Tamstorf, K.

1971-01-01

Recent efforts in our laboratories have concentrated on the development of an all solid state gas sensor, by combining solid electrolyte (ion exchange membrane) technology with advanced thin film deposition processes. With the proper bias magnitude and polarity these miniature electro-chemical,cells show remarkable current responses for many common pollution gases. Current activity is now focused on complementing a multiple array (matrix) of these solid state sensors, with a digital electronic scanner device possessing "scan-compare-identify-alarm: capability. This innovative approach to multi-component pollutant gas analysis may indeed be the advanced prototype for the "third generation" class of pollution analysis instrumentation so urgently needed in the decade ahead.

High-performance multi-functional reverse osmosis membranes obtained by carbon nanotube·polyamide nanocomposite

PubMed Central

Inukai, Shigeki; Cruz-Silva, Rodolfo; Ortiz-Medina, Josue; Morelos-Gomez, Aaron; Takeuchi, Kenji; Hayashi, Takuya; Tanioka, Akihiko; Araki, Takumi; Tejima, Syogo; Noguchi, Toru; Terrones, Mauricio; Endo, Morinobu

2015-01-01

Clean water obtained by desalinating sea water or by purifying wastewater, constitutes a major technological objective in the so-called water century. In this work, a high-performance reverse osmosis (RO) composite thin membrane using multi-walled carbon nanotubes (MWCNT) and aromatic polyamide (PA), was successfully prepared by interfacial polymerization. The effect of MWCNT on the chlorine resistance, antifouling and desalination performances of the nanocomposite membranes were studied. We found that a suitable amount of MWCNT in PA, 15.5 wt.%, not only improves the membrane performance in terms of flow and antifouling, but also inhibits the chlorine degradation on these membranes. Therefore, the present results clearly establish a solid foundation towards more efficient large-scale water desalination and other water treatment processes. PMID:26333385

Solid-state curved focal plane arrays

NASA Technical Reports Server (NTRS)

Jones, Todd (Inventor); Nikzad, Shouleh (Inventor); Hoenk, Michael (Inventor)

2010-01-01

The present invention relates to curved focal plane arrays. More specifically, the present invention relates to a system and method for making solid-state curved focal plane arrays from standard and high-purity devices that may be matched to a given optical system. There are two ways to make a curved focal plane arrays starting with the fully fabricated device. One way, is to thin the device and conform it to a curvature. A second way, is to back-illuminate a thick device without making a thinned membrane. The thick device is a special class of devices; for example devices fabricated with high purity silicon. One surface of the device (the non VLSI fabricated surface, also referred to as the back surface) can be polished to form a curved surface.

Molecular Functionalization of Graphene Oxide for Next-Generation Wearable Electronics.

PubMed

Zarrin, Hadis; Sy, Serubbabel; Fu, Jing; Jiang, Gaopeng; Kang, Keunwoo; Jun, Yun-Seok; Yu, Aiping; Fowler, Michael; Chen, Zhongwei

2016-09-28

Acquiring reliable and efficient wearable electronics requires the development of flexible electrolyte membranes (EMs) for energy storage systems with high performance and minimum dependency on the operating conditions. Herein, a freestanding graphene oxide (GO) EM is functionalized with 1-hexyl-3-methylimidazolium chloride (HMIM) molecules via both covalent and noncovalent bonds induced by esterification reactions and electrostatic πcation-π stacking, respectively. Compared to the commercial polymeric membrane, the thin HMIM/GO membrane demonstrates not only slightest performance sensitivity to the operating conditions but also a superior hydroxide conductivity of 0.064 ± 0.0021 S cm(-1) at 30% RH and room temperature, which was 3.8 times higher than that of the commercial membrane at the same conditions. To study the practical application of the HMIM/GO membranes in wearable electronics, a fully solid-state, thin, flexible zinc-air battery and supercapacitor are made exhibiting high battery performance and capacitance at low humidified and room temperature environment, respectively, favored by the bonded HMIM molecules on the surface of GO nanosheets. The results of this study disclose the strong potential of manipulating the chemical structure of GO to work as a lightweight membrane in wearable energy storage devices, possessing highly stable performance at different operating conditions, especially at low relative humidity and room temperature.

Lithiated Nafion as polymer electrolyte for solid-state lithium sulfur batteries using carbon-sulfur composite cathode

NASA Astrophysics Data System (ADS)

Gao, Jing; Sun, Chunshui; Xu, Lei; Chen, Jian; Wang, Chong; Guo, Decai; Chen, Hao

2018-04-01

Due to flexible property and light weight, the lithiated Nafion membrane swollen with PC (PC-Li-Nafion) has been employed as both solid-state electrolyte and separator to fabricate solid-state Li-S cells. The electrochemical measurements of PC-Li-Nafion membrane show that its Li-ion transference number is 0.928, ionic conductivity of 2.1 × 10-4 S cm-1 can be achieved at 70 °C and its electrochemical window is 0 ∼ +4.1 V vs. Li+/Li. It is observed that the Li dendrites are suppressed by using PC-Li-Nafion membrane due to its single-ion conducting property. The amounts of Li-Nafion resin binder and conductive carbon in the cathode are optimized as 40% and 10% respectively to make a balance of ionic and electronic conductivities. A thin-layer Li-Nafion resin with a thickness of around 2 μm is fabricated between the cathode and PC-Li-Nafion membrane to improve the interfacial contact and further enhance the specific capacity of the cell. When measured at 70 °C, the Li-S cell delivers a reversible specific capacity of 1072.8 mAh g-1 (S) at 0.05 C and 895 mAh g-1 (S) at 1 C. The capacity retention at 1 C is 89% after 100 cycles. These results suggest that high-performance solid-state Li-S cells can be fabricated with the Li-Nafion polymer electrolyte.

Rupture and Spreading Dynamics of Lipid Membranes on a Solid Surface

NASA Astrophysics Data System (ADS)

Perazzo, Antonio; Shin, Sangwoo; Colosqui, Carlos; Young, Yuan-Nan; Stone, Howard A.

2017-11-01

The spreading of lipid membranes on solid surfaces is a dynamic phenomenon relevant to drug delivery, endocytosis, biofouling, and the synthesis of supported lipid bilayers. Current technological developments are limited by an incomplete understanding of the spreading and adhesion dynamics of a lipid bilayer under different physicochemical conditions. Here, we present recent experimental and theoretical results for the spreading of giant unilamellar vesicles (GUVs), where the vesicle shell consists of a lipid bilayer. In particular, we study the effect of different background ion concentrations, osmolarity mismatches between the interior and the exterior of the vesicles, and different surface chemistries of the glass substrate. In all of the studied cases, we observe a delay time before a GUV in contact with the solid surface eventually ruptures. The rupture kinetics and subsequent spreading dynamics is controlled by the ionic screening within the thin film of liquid between the vesicle and the surface. Different rupture mechanisms, mobilities of the spreading vesicle, and degrees of substrate coverage are observed by varying the electrolyte concentration, solid surface charge, and osmolarity mismatch.

Large apparent electric size of solid-state nanopores due to spatially extended surface conduction.

PubMed

Lee, Choongyeop; Joly, Laurent; Siria, Alessandro; Biance, Anne-Laure; Fulcrand, Rémy; Bocquet, Lydéric

2012-08-08

Ion transport through nanopores drilled in thin membranes is central to numerous applications, including biosensing and ion selective membranes. This paper reports experiments, numerical calculations, and theoretical predictions demonstrating an unexpectedly large ionic conduction in solid-state nanopores, taking its origin in anomalous entrance effects. In contrast to naive expectations based on analogies with electric circuits, the surface conductance inside the nanopore is shown to perturb the three-dimensional electric current streamlines far outside the nanopore in order to meet charge conservation at the pore entrance. This unexpected contribution to the ionic conductance can be interpreted in terms of an apparent electric size of the solid-state nanopore, which is much larger than its geometric counterpart whenever the number of charges carried by the nanopore surface exceeds its bulk counterpart. This apparent electric size, which can reach hundreds of nanometers, can have a major impact on the electrical detection of translocation events through nanopores, as well as for ionic transport in biological nanopores.

The Molecular Structure of Human Red Blood Cell Membranes from Highly Oriented, Solid Supported Multi-Lamellar Membranes

PubMed Central

Himbert, Sebastian; Alsop, Richard J.; Rose, Markus; Hertz, Laura; Dhaliwal, Alexander; Moran-Mirabal, Jose M.; Verschoor, Chris P.; Bowdish, Dawn M. E.; Kaestner, Lars; Wagner, Christian; Rheinstädter, Maikel C.

2017-01-01

We prepared highly oriented, multi-lamellar stacks of human red blood cell (RBC) membranes applied on silicon wafers. RBC ghosts were prepared by hemolysis and applied onto functionalized silicon chips and annealed into multi-lamellar RBC membranes. High resolution X-ray diffraction was used to determine the molecular structure of the stacked membranes. We present direct experimental evidence that these RBC membranes consist of nanometer sized domains of integral coiled-coil peptides, as well as liquid ordered (lo) and liquid disordered (ld) lipids. Lamellar spacings, membrane and hydration water layer thicknesses, areas per lipid tail and domain sizes were determined. The common drug aspirin was added to the RBC membranes and found to interact with RBC membranes and preferably partition in the head group region of the lo domain leading to a fluidification of the membranes, i.e., a thinning of the bilayers and an increase in lipid tail spacing. Our results further support current models of RBC membranes as patchy structures and provide unprecedented structural details of the molecular organization in the different domains. PMID:28045119

The Molecular Structure of Human Red Blood Cell Membranes from Highly Oriented, Solid Supported Multi-Lamellar Membranes

NASA Astrophysics Data System (ADS)

Himbert, Sebastian; Alsop, Richard J.; Rose, Markus; Hertz, Laura; Dhaliwal, Alexander; Moran-Mirabal, Jose M.; Verschoor, Chris P.; Bowdish, Dawn M. E.; Kaestner, Lars; Wagner, Christian; Rheinstädter, Maikel C.

2017-01-01

We prepared highly oriented, multi-lamellar stacks of human red blood cell (RBC) membranes applied on silicon wafers. RBC ghosts were prepared by hemolysis and applied onto functionalized silicon chips and annealed into multi-lamellar RBC membranes. High resolution X-ray diffraction was used to determine the molecular structure of the stacked membranes. We present direct experimental evidence that these RBC membranes consist of nanometer sized domains of integral coiled-coil peptides, as well as liquid ordered (lo) and liquid disordered (ld) lipids. Lamellar spacings, membrane and hydration water layer thicknesses, areas per lipid tail and domain sizes were determined. The common drug aspirin was added to the RBC membranes and found to interact with RBC membranes and preferably partition in the head group region of the lo domain leading to a fluidification of the membranes, i.e., a thinning of the bilayers and an increase in lipid tail spacing. Our results further support current models of RBC membranes as patchy structures and provide unprecedented structural details of the molecular organization in the different domains.

Implications of changes in solids retention time on long term evolution of sludge filterability in anaerobic membrane bioreactors treating high strength industrial wastewater.

PubMed

Dereli, Recep Kaan; Grelot, Aurelie; Heffernan, Barry; van der Zee, Frank P; van Lier, Jules B

2014-08-01

Long-term experiments were conducted to assess the impact of changing the solids retention time (SRT) on sludge filterability in anaerobic membrane bioreactors (AnMBRs), treating corn-based bioethanol thin stillage. Well established parameters, such as capillary suction time (CST) and specific resistance to filtration (SRF), developed for sludge dewatering, were used to evaluate the SRT effect on sludge filterability. Our results clearly demonstrated that SRT is one of the most important factors influencing sludge filterability in AnMBRs. SRT effects the accumulation of fine particles and solutes, which were found to affect attainable flux and fouling, in reactor broth. A better filterability was observed at a SRT of 20 days compared to elevated SRTs, i.e. 50 days. A clear correlation between sludge filtration characteristics and membrane filtration resistance could not be established especially at short SRTs, whereas many parameters such as total suspended solids (TSS), CST, soluble microbial products (SMP) and supernatant filterability were found to be mutually correlated. Net membrane fluxes between 9 and 13 L m(-2) h(-1) were obtained at 0.5 m s(-1) cross-flow velocity and the long term fouling was controlled by using frequent filtration and backwash cycles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ceramic distribution members for solid state electrolyte cells and method of producing

NASA Technical Reports Server (NTRS)

Clark, Douglas J. (Inventor); Galica, Leo M. (Inventor); Losey, Robert W. (Inventor); Suitor, Jerry W. (Inventor)

1993-01-01

A solid state electrolyte cells apparatus and method of producing is disclosed. The apparatus can be used for separating oxygen from an oxygen-containing feedstock or as a fuel cell for reacting fluids. Cells can be stacked so that fluids can be introduced and removed from the apparatus through ceramic distribution members having ports designed for distributing the fluids in parallel flow to and from each cell. The distribution members can also serve as electrodes to membranes or as membrane members between electrodes. The distribution member design does not contain any horizontal internal ports which allows the member to be thin. A method of tape casting in combination with an embossing method allows intricate radial ribs and bosses to be formed on each distribution member. The bosses serve as seals for the ports and allow the distribution members to be made without any horizontal internal ports.

Method of producing ceramic distribution members for solid state electrolyte cells

NASA Technical Reports Server (NTRS)

Clark, Douglas J. (Inventor); Galica, Leo M. (Inventor); Losey, Robert W. (Inventor); Suitor, Jerry W. (Inventor)

1995-01-01

A solid state electrolyte cells apparatus and method of producing is disclosed. The apparatus can be used for separating oxygen from an oxygen-containing feedstock or as a fuel cell for reacting fluids. Cells can be stacked so that fluids can be introduced and removed from the apparatus through ceramic distribution members having ports designed for distributing the fluids in parallel flow to and from each cell. The distribution members can also serve as electrodes to membranes or as membrane members between electrodes, The distribution member design does not contain any horizontal internal ports which allows the member to be thin. A method of tape casting in combination with an embossing method allows intricate radial ribs and bosses to be formed on each distribution member. The bosses serve as seals for the ports and allow the distribution members to be made without any horizontal internal ports.

A Novel MicroElectroMechanical System (MEMS) Device for Passive Sampling of Hydrophobic Compounds

DTIC Science & Technology

2011-05-01

bioavailability  Samplers are removed, extracted for CoC, analyzed ▬ For organics: solid phase micro extraction ( SPME ) fibers, semi- permeable membrane...devices (SPMD), polyoxymethylene (POM) ▬ For metals: diffuse gradients in thin films (DGT) SPME fiber ESTCP project, Reible and Lotufo Applications to...Predict Bioaccumulation You et al. 2006, EST, 40: 6348 SPME concentrations were predictive of tissue concentrations of PCBs in field-contaminated

Deformation in Micro Roll Forming of Bipolar Plate

NASA Astrophysics Data System (ADS)

Zhang, P.; Pereira, M.; Rolfe, B.; Daniel, W.; Weiss, M.

2017-09-01

Micro roll forming is a new processing technology to produce bipolar plates for Proton Exchange Membrane Fuel Cells (PEMFC) from thin stainless steel foil. To gain a better understanding of the deformation of the material in this process, numerical studies are necessary before experimental implementation. In general, solid elements with several layers through the material thickness are required to analyse material thinning in processes where the deformation mode is that of bending combined with tension, but this results in high computational costs. This pure solid element approach is especially time-consuming when analysing roll forming processes which generally involves feeding a long strip through a number of successive roll stands. In an attempt to develop a more efficient modelling approach without sacrificing accuracy, two solutions are numerically analysed with ABAQUS/Explicit in this paper. In the first, a small patch of solid elements over the strip width and in the centre of the “pre-cut” sheet is coupled with shell elements while in the second approach pure shell elements are used to discretize the full sheet. In the first approach, the shell element enables accounting for the effect of material being held in the roll stands on material flow while solid elements can be applied to analyse material thinning in a small discrete area of the sheet. Experimental micro roll forming trials are performed to prove that the coupling of solid and shell elements can give acceptable model accuracy while using shell elements alone is shown to result in major deviations between numerical and experimental results.

Flight in hairy and sticky situations

NASA Astrophysics Data System (ADS)

Santhanakrishnan, Arvind

2017-11-01

The smallest flying insects such as thrips and fairyflies have body lengths less than 1 mm. Despite their ecological importance, the fluid dynamic mechanisms that enable very tiny insects to generate lift at Reynolds number (Re) on the order of 10 remain unclear. Flapping motion in tiny insects is often characterized by `clap and fling' wing-wing interaction. Further, these insects possess wings consisting of a thin solid membrane with long bristles on the fringes. Why is there a noted biological preference in almost all tiny insects to employ interacting bristled wings under highly viscous conditions that would require large forces to peel the wings apart? In this talk, I will present numerical and experimental studies examining the role of bristled wings in clap and fling aerodynamics. At Re = 10, bristled wings are observed to reduce both lift and drag forces as compared to geometrically equivalent solid (non-bristled) wings. Recirculating flow through the bristles leads to disproportionally larger drag reduction by bristled wings, as compared to lift reduction between bristled and solid wings. The impact of alterations to bristled wing design variables, including spacing between bristles and ratio of solid membrane to total wing areas, on aerodynamic force coefficients and scalability with Re will be discussed.

Three-Dimensional Microphase Separation and Synergistic Permeability in Stacked Lipid–Polymer Hybrid Membranes

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

Kang, Minjee; Lee, Byeongdu; Leal, Cecilia

Here, we present new structures of soft-material thin films that augment the functionality of substrate-mediated delivery systems. A hybrid material composed of phospholipids and block copolymers adopts a multilayered membrane structure supported on a solid surface. The hybrid films comprise intentional intramembrane heterogeneities that register across multilayers. These stacked domains convey unprecedented enhancement and control of permeability of solutes across micrometer-thick films. Using grazing incidence X-ray scattering, phase contrast atomic force microscopy, and confocal microscopy, we observed that in each lamella, lipid and polymers partition unevenly within the membrane plane segregating into lipid- or polymer-rich domains. Interestingly, we found evidencemore » that like-domains align in registry across multilayers, thereby making phase separation three-dimensional. Phase boundaries exist over extended length scales to compensate the height mismatch between lipid and polymer molecules. We show that microphase separation in hybrid films can be exploited to augment the capability of drug-eluting substrates. Lipid–polymer hybrid films loaded with paclitaxel show synergistic permeability of drug compared to single-component counterparts. We present a thorough structural study of stacked lipid–polymer hybrid membranes and propose that the presence of registered domains and domain boundaries impart enhanced drug release functionality. This work offers new perspectives in designing thin films for controlled delivery applications« less

Three-Dimensional Microphase Separation and Synergistic Permeability in Stacked Lipid–Polymer Hybrid Membranes

DOE PAGES

Kang, Minjee; Lee, Byeongdu; Leal, Cecilia

2017-10-20

Here, we present new structures of soft-material thin films that augment the functionality of substrate-mediated delivery systems. A hybrid material composed of phospholipids and block copolymers adopts a multilayered membrane structure supported on a solid surface. The hybrid films comprise intentional intramembrane heterogeneities that register across multilayers. These stacked domains convey unprecedented enhancement and control of permeability of solutes across micrometer-thick films. Using grazing incidence X-ray scattering, phase contrast atomic force microscopy, and confocal microscopy, we observed that in each lamella, lipid and polymers partition unevenly within the membrane plane segregating into lipid- or polymer-rich domains. Interestingly, we found evidencemore » that like-domains align in registry across multilayers, thereby making phase separation three-dimensional. Phase boundaries exist over extended length scales to compensate the height mismatch between lipid and polymer molecules. We show that microphase separation in hybrid films can be exploited to augment the capability of drug-eluting substrates. Lipid–polymer hybrid films loaded with paclitaxel show synergistic permeability of drug compared to single-component counterparts. We present a thorough structural study of stacked lipid–polymer hybrid membranes and propose that the presence of registered domains and domain boundaries impart enhanced drug release functionality. This work offers new perspectives in designing thin films for controlled delivery applications« less

Claisen thermally rearranged (CTR) polymers

PubMed Central

Tena, Alberto; Rangou, Sofia; Shishatskiy, Sergey; Filiz, Volkan; Abetz, Volker

2016-01-01

Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications. PMID:27482538

Claisen thermally rearranged (CTR) polymers.

PubMed

Tena, Alberto; Rangou, Sofia; Shishatskiy, Sergey; Filiz, Volkan; Abetz, Volker

2016-07-01

Thermally rearranged (TR) polymers, which are considered the next-generation of membrane materials because of their excellent transport properties and high thermal and chemical stability, are proven to have significant drawbacks because of the high temperature required for the rearrangement and low degree of conversion during this process. We demonstrate that using a [3,3]-sigmatropic rearrangement, the temperature required for the rearrangement of a solid glassy polymer was reduced by 200°C. Conversions of functionalized polyimide to polybenzoxazole of more than 97% were achieved. These highly mechanically stable polymers were almost five times more permeable and had more than two times higher degrees of conversion than the reference polymer treated under the same conditions. Properties of these second-generation TR polymers provide the possibility of preparing efficient polymer membranes in a form of, for example, thin-film composite membranes for various gas and liquid membrane separation applications.

Ethanol effects on binary and ternary supported lipid bilayers with gel/fluid domains and lipid rafts.

PubMed

Marquês, Joaquim T; Viana, Ana S; De Almeida, Rodrigo F M

2011-01-01

Ethanol-lipid bilayer interactions have been a recurrent theme in membrane biophysics, due to their contribution to the understanding of membrane structure and dynamics. The main purpose of this study was to assess the interplay between membrane lateral heterogeneity and ethanol effects. This was achieved by in situ atomic force microscopy, following the changes induced by sequential ethanol additions on supported lipid bilayers formed in the absence of alcohol. Binary phospholipid mixtures with a single gel phase, dipalmitoylphosphatidylcholine (DPPC)/cholesterol, gel/fluid phase coexistence DPPC/dioleoylphosphatidylcholine (DOPC), and ternary lipid mixtures containing cholesterol, mimicking lipid rafts (DOPC/DPPC/cholesterol and DOPC/sphingomyelin/cholesterol), i.e., with liquid ordered/liquid disordered (ld/lo) phase separation, were investigated. For all compositions studied, and in two different solid supports, mica and silicon, domain formation or rearrangement accompanied by lipid bilayer thinning and expansion was observed. In the case of gel/fluid coexistence, low ethanol concentrations lead to a marked thinning of the fluid but not of the gel domains. In the case of ld/lo all the bilayer thins simultaneously by a similar extent. In both cases, only the more disordered phase expanded significantly, indicating that ethanol increases the proportion of disordered domains. Water/bilayer interfacial tension variation and freezing point depression, inducing acyl chain disordering (including opening and looping), tilting, and interdigitation, are probably the main cause for the observed changes. The results presented herein demonstrate that ethanol influences the bilayer properties according to membrane lateral organization. Copyright © 2010 Elsevier B.V. All rights reserved.

Protein-Containing Lipid Bilayers Intercalated with Size-Matched Mesoporous Silica Thin Films

DOE PAGES

Isaksson, Simon; Watkins, Erik Benjamin; Browning, Kathryn L.; ...

2016-11-23

Here, proteins are key components in a multitude of biological processes, of which the functions carried out by transmembrane (membrane-spanning) proteins are especially demanding for investigations. This is because this class of protein needs to be incorporated into a lipid bilayer representing its native environment, and in addition, many experimental conditions also require a solid support for stabilization and analytical purposes. The solid support substrate may, however, limit the protein functionality due to protein–material interactions and a lack of physical space. We have in this work tailored the pore size and pore ordering of a mesoporous silica thin film tomore » match the native cell-membrane arrangement of the transmembrane protein human aquaporin 4 (hAQP4). Using neutron reflectivity (NR), we provide evidence of how substrate pores host the bulky water-soluble domain of hAQP4, which is shown to extend 7.2 nm into the pores of the substrate. Complementary surface analytical tools, including quartz crystal microbalance with dissipation monitoring (QCM-D) and fluorescence microscopy, revealed successful protein-containing supported lipid bilayer (pSLB) formation on mesoporous silica substrates, whereas pSLB formation was hampered on nonporous silica. Additionally, electron microscopy (TEM and SEM), light scattering (DLS and stopped-flow), and small-angle X-ray scattering (SAXS) were employed to provide a comprehensive characterization of this novel hybrid organic–inorganic interface, the tailoring of which is likely to be generally applicable to improve the function and stability of a broad range of membrane proteins containing water-soluble domains.« less

Protein-Containing Lipid Bilayers Intercalated with Size-Matched Mesoporous Silica Thin Films

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

Isaksson, Simon; Watkins, Erik Benjamin; Browning, Kathryn L.

Here, proteins are key components in a multitude of biological processes, of which the functions carried out by transmembrane (membrane-spanning) proteins are especially demanding for investigations. This is because this class of protein needs to be incorporated into a lipid bilayer representing its native environment, and in addition, many experimental conditions also require a solid support for stabilization and analytical purposes. The solid support substrate may, however, limit the protein functionality due to protein–material interactions and a lack of physical space. We have in this work tailored the pore size and pore ordering of a mesoporous silica thin film tomore » match the native cell-membrane arrangement of the transmembrane protein human aquaporin 4 (hAQP4). Using neutron reflectivity (NR), we provide evidence of how substrate pores host the bulky water-soluble domain of hAQP4, which is shown to extend 7.2 nm into the pores of the substrate. Complementary surface analytical tools, including quartz crystal microbalance with dissipation monitoring (QCM-D) and fluorescence microscopy, revealed successful protein-containing supported lipid bilayer (pSLB) formation on mesoporous silica substrates, whereas pSLB formation was hampered on nonporous silica. Additionally, electron microscopy (TEM and SEM), light scattering (DLS and stopped-flow), and small-angle X-ray scattering (SAXS) were employed to provide a comprehensive characterization of this novel hybrid organic–inorganic interface, the tailoring of which is likely to be generally applicable to improve the function and stability of a broad range of membrane proteins containing water-soluble domains.« less

Lipid bilayer thickness determines cholesterol's location in model membranes

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

Marquardt, Drew; Heberle, Frederick A.; Greathouse, Denise V.

Cholesterol is an essential biomolecule of animal cell membranes, and an important precursor for the biosynthesis of certain hormones and vitamins. It is also thought to play a key role in cell signaling processes associated with functional plasma membrane microdomains (domains enriched in cholesterol), commonly referred to as rafts. In all of these diverse biological phenomena, the transverse location of cholesterol in the membrane is almost certainly an important structural feature. Using a combination of neutron scattering and solid-state 2H NMR, we have determined the location and orientation of cholesterol in phosphatidylcholine (PC) model membranes having fatty acids of differentmore » lengths and degrees of unsaturation. The data establish that cholesterol reorients rapidly about the bilayer normal in all the membranes studied, but is tilted and forced to span the bilayer midplane in the very thin bilayers. The possibility that cholesterol lies flat in the middle of bilayers, including those made from PC lipids containing polyunsaturated fatty acids (PUFAs), is ruled out. Finally, these results support the notion that hydrophobic thickness is the primary determinant of cholesterol's location in membranes.« less

Lipid bilayer thickness determines cholesterol's location in model membranes

DOE PAGES

Marquardt, Drew; Heberle, Frederick A.; Greathouse, Denise V.; ...

2016-10-11

Cholesterol is an essential biomolecule of animal cell membranes, and an important precursor for the biosynthesis of certain hormones and vitamins. It is also thought to play a key role in cell signaling processes associated with functional plasma membrane microdomains (domains enriched in cholesterol), commonly referred to as rafts. In all of these diverse biological phenomena, the transverse location of cholesterol in the membrane is almost certainly an important structural feature. Using a combination of neutron scattering and solid-state 2H NMR, we have determined the location and orientation of cholesterol in phosphatidylcholine (PC) model membranes having fatty acids of differentmore » lengths and degrees of unsaturation. The data establish that cholesterol reorients rapidly about the bilayer normal in all the membranes studied, but is tilted and forced to span the bilayer midplane in the very thin bilayers. The possibility that cholesterol lies flat in the middle of bilayers, including those made from PC lipids containing polyunsaturated fatty acids (PUFAs), is ruled out. Finally, these results support the notion that hydrophobic thickness is the primary determinant of cholesterol's location in membranes.« less

The obtaining and properties of asymmetric ion transport membrane for separating of oxygen from air

NASA Astrophysics Data System (ADS)

Solovieva, A. A.; Kulbakin, I. V.

2018-04-01

The bilayer oxygen-permeable membrane, consisting of a thin-film dense composite based on Co3O4 - 36 wt. % Bi2O3, and of a porous ceramic substrate of Co2SiO4, was synthesized and characterized. The way for obtaining of porous ceramic based on cobalt silicate was found, while the microstructure and the mechanical properties of porous ceramic were studied. Layered casting with post-pressing was used to cover the surface of porous support of Co2SiO4 by the Co3O4 - 36 wt. % Bi2O3 - based film. Transport properties of the asymmetric membrane have been studied, the kinetic features of oxygen transport have been established, and the characteristic thickness of the membrane has been estimated. The methods to prevent the high-temperature creep of ion transport membranes based on solid/molten oxides, which are the promising ones for obtaining of pure oxygen from air, are proposed and discussed.

Determination of free and deconjugated testosterone and epitestosterone in urine using SPME and LC-MS/MS.

PubMed

Zhan, Yanwei; Musteata, Florin M; Basset, Fabien A; Pawliszyn, Janusz

2011-01-01

A thin sheet of polydimethylsilosane membrane was used as an extraction phase for solid-phase microextraction. Compared with fiber or rod solid-phase microextraction geometries, the thin film exhibited much higher extraction capacity without sacrificing extraction time due to its higher area-to-volume ratio. The analytical method involved direct extraction of unconjugated testosterone (T) and epitestosterone (ET) followed by separation on a C18 column and detection by selected reaction monitoring in positive ionization mode. The limit of detection was 1 ng/l for both T and ET. After method validation, free (unconjugated) T and ET were extracted and quantified in real samples. Since T and ET are extensively metabolized, the proposed method was also applied to extract the steroids after enzymatic deconjugation of urinary-excreted steroid glucuronides. The proposed method allows quantification of both conjugated and unconjugated steroids, and revealed that there was a change in the ratio of T to ET after enzymatic deconjugation, indicating different rates of metabolism.

Reliability of Multilayer Copper/Polyimide

DTIC Science & Technology

1993-11-01

LOIS H. WALSH R eliability R esearch E ng ineer -, . .....................-------- - - Reliability Physics Branch i-1’ , ý, Ay cci~i• es "AL f, , or Dist...average of 925 hours The chamber "as operated at 85 C󈨙 10 r h All the samples showed initial dielectric constant values consistent w%,ith previous...19. Matsumoto, 0., Katagiri, T., Thin Solid Films, 146, 283 (1987) 20. Malladi , D.P., J Membrane Sci., 19, 209 (1984) 21. Schubert, P.J., Nevin, J.H

Ultra-thin Oxide Membranes: Synthesis and Carrier Transport

NASA Astrophysics Data System (ADS)

Sim, Jai Sung

Self-supported freestanding membranes are films that are devoid of any underlying supporting layers. The key advantage of such structures is that, due to the lack of substrate effects - both mechanical and chemical, the true native properties of the material can be probed. This is crucial since many of the studies done on materials that are used as freestanding membranes are done as films clamped to substrates or in the bulk form. This thesis focuses on the synthesis and fabrication as well as electrical studies of free standing ultrathin < 40nm oxide membranes. It also is one of the first demonstrations for electrically probing nanoscale freestanding oxide membranes. Fabrication of such membranes is non-trivial as oxide materials are often brittle and difficult to handle. Therefore, it requires an understanding of thin plate mechanics coupled with controllable thin film deposition process. Taking things a step further, to electrically probe these membranes required design of complex device architecture and extensive optimization of nano-fabrication processes. The challenges and optimized fabrication method of such membranes are demonstrated. Three materials are probed in this study, VO2, TiO2, and CeO2. VO2 for understanding structural considerations for electronic phase change and nature of ionic liquid gating, TiO2 and CeO2 for understanding surface conduction properties and surface chemistry. The VO2 study shows shift in metal-insulator transition (MIT) temperature arising from stress relaxation and opening of the hysteresis. The ionic liquid gating studies showed reversible modulation of channel resistance and allowed distinguishing bulk process from the surface effects. Comparing the ionic liquid gating experiments to hydrogen doping experiments illustrated that ionic liquid gating can be a surface limited electrostatic effect, if the critical voltage threshold is not exceeded. TiO2 study shows creation of non-stoichiometric forms under ion milling. Utilizing focused ion beam milling, thin membranes of Ti xOy of 100-300 nm thickness have been created. TEM studies indicated polycrystallinity and presence of twins in the FIB-milled nanowalls. Compositional analysis in the transmission electron microscope also showed reduced content of oxygen, confirming non-stoichiometry. Temperature dependence of the electrical resistivity of the nanowall showed semiconducting behavior with an activation energy different from that of TiO2 single crystals and was attributed to formation of TinO2n-1 phases after FIB processing. The CeO2 study involved high temperature conductivity studies on substrate-free self-supported nano-crystalline ceria membranes up to 800 K. Increasing conductivity with oxygen partial pressure directly opposing the behavior of thin film devices 'clamped' by substrate has been observed. This illustrate that the relaxed nature of free standing membranes, and increased surface to volume ratio enables more sensitive electrical response to oxygen adsorption which could have implications for their use in oxygen storage devices, solid oxide fuel cells, and chemical sensors. The work in this thesis advances the understanding of materials in freestanding membrane form and advances fabrication techniques that have not been explored before, having implications for sensors, actuators, SOFC, memristors, and physics of quasi-2D materials.

Membrane thinning for efficient CO2 capture

PubMed Central

Selyanchyn, Roman; Fujikawa, Shigenori

2017-01-01

Abstract Enhancing the fluxes in gas separation membranes is required for utilizing the membranes on a mass scale for CO2 capture. Membrane thinning is one of the most promising approaches to achieve high fluxes. In addition, sophisticated molecular transport across membranes can boost gas separation performance. In this review, we attempt to summarize the current state of CO2 separation membranes, especially from the viewpoint of thinning the selective layers and the membrane itself. The gas permeation behavior of membranes with ultimate thicknesses and their future directions are discussed. PMID:29152016

Effects of DMSO and glycerol additives on the property of polyamide reverse osmosis membrane.

PubMed

Wu, Fengjing; Liu, Xiaojuan; Au, Chaktong

2016-10-01

The polyamide reverse osmosis (RO) membranes were prepared through interfacial polymerization of m-phenylenediamine (MPD) and trimesoyl chloride (TMC). The use of dimethyl sulfoxide (DMSO) and glycerol as additives for the formation of thin-film composite (TFC) was investigated. We studied the effect of DMSO and glycerol addition on membrane property and RO performance. Microscopic morphology was examined by atomic force microscopy and scanning electron microscopy. The surface hydrophilicity was characterized on the basis of water contact angle and surface solid-liquid interfacial free energy (-ΔG SL ). Water flux and salt rejection ability of the membranes prepared with or without the additives were evaluated by cross-flow RO tests. The results reveal that the addition of DMSO and glycerol strongly influences the property of the TFC RO membrane. Compared to the MPD/TMC membrane fabricated without DMSO and glycerol, the MPD/TMC/DMSO/glycerol membrane has a rougher surface and is more hydrophilic, showing smaller water contact angle and larger -ΔG SL value. Without decrease in salt rejection ability, the MPD/TMC/DMSO/glycerol membrane shows water flux significantly larger than that of the MPD/TMC membrane. The unique property of the MPD/TMC/DMSO/glycerol membrane is attributed to the cooperative effect of DMSO and glycerol on membrane structure during the interfacial polymerization process.

High power density proton exchange membrane fuel cells

NASA Technical Reports Server (NTRS)

Murphy, Oliver J.; Hitchens, G. Duncan; Manko, David J.

1993-01-01

Proton exchange membrane (PEM) fuel cells use a perfluorosulfonic acid solid polymer film as an electrolyte which simplifies water and electrolyte management. Their thin electrolyte layers give efficient systems of low weight, and their materials of construction show extremely long laboratory lifetimes. Their high reliability and their suitability for use in a microgravity environment makes them particularly attractive as a substitute for batteries in satellites utilizing high-power, high energy-density electrochemical energy storage systems. In this investigation, the Dow experimental PEM (XUS-13204.10) and unsupported high platinum loading electrodes yielded very high power densities, of the order of 2.5 W cm(exp -2). A platinum black loading of 5 mg per cm(exp 2) was found to be optimum. On extending the three-dimensional reaction zone of fuel cell electrodes by impregnating solid polymer electrolyte into the electrode structures, Nafion was found to give better performance than the Dow experimental PEM. The depth of penetration of the solid polymer electrolyte into electrode structures was 50-70 percent of the thickness of the platinum-catalyzed active layer. However, the degree of platinum utilization was only 16.6 percent and the roughness factor of a typical electrode was 274.

Electrochemical Protection of Thin Film Electrodes in Solid State Nanopores

PubMed Central

Harrer, Stefan; Waggoner, Philip S.; Luan, Binquan; Afzali-Ardakani, Ali; Goldfarb, Dario L.; Peng, Hongbo; Martyna, Glenn; Rossnagel, Stephen M.; Stolovitzky, Gustavo A.

2011-01-01

We have eliminated electrochemical surface oxidation and reduction as well as water decomposition inside sub-5-nm wide nanopores in conducting TiN membranes using a surface passivation technique. Nanopore ionic conductances, and therefore pore diameters, were unchanged in passivated pores after applying potentials of ±4.5 V for as long as 24 h. Water decomposition was eliminated by using aqueous 90% glycerol solvent. The use of a protective self-assembled monolayer of hexadecylphosphonic acid was also investigated. PMID:21597142

Pentiptycene-Based Polyurethane with Enhanced Mechanical Properties and CO2-Plasticization Resistance for Thin Film Gas Separation Membranes.

PubMed

Pournaghshband Isfahani, Ali; Sadeghi, Morteza; Wakimoto, Kazuki; Shrestha, Binod Babu; Bagheri, Rouhollah; Sivaniah, Easan; Ghalei, Behnam

2018-05-23

The development of thin film composite (TFC) membranes offers an opportunity to achieve the permeability/selectivity requirements for optimum CO 2 separation performance. However, the durability and performance of thin film gas separation membranes are mostly challenged by weak mechanical properties and high CO 2 plasticization. Here, we designed new polyurethane (PU) structures with bulky aromatic chain extenders that afford preferred mechanical properties for ultra-thin-film formation. An improvement of about 1500% in Young's modulus and 600% in hardness was observed for pentiptycene-based PUs compared to the typical PU membranes. Single (CO 2 , H 2 , CH 4 , and N 2 ) and mixed (CO 2 /N 2 and CO 2 /CH 4 ) gas permeability tests were performed on the PU membranes. The resulting TFC membranes showed a high CO 2 permeance up to 1400 GPU (10 -6 cm 3 (STP) cm -2 s -1 cmHg -1 ) and the CO 2 /N 2 and CO 2 /H 2 selectivities of about 22 and 2.1, respectively. The enhanced mechanical properties of pentiptycene-based PUs result in high-performance thin membranes with the similar selectivity of the bulk polymer. The thin film membranes prepared from pentiptycene-based PUs also showed a twofold enhanced plasticization resistance compared to non-pentiptycene-containing PU membranes.

Pressure-assisted synthesis of HKUST-1 thin film on polymer hollow fiber at room temperature toward gas separation.

PubMed

Mao, Yiyin; Li, Junwei; Cao, Wei; Ying, Yulong; Sun, Luwei; Peng, Xinsheng

2014-03-26

The scalable fabrication of continuous and defect-free metal-organic framework (MOF) films on the surface of polymeric hollow fibers, departing from ceramic supported or dense composite membranes, is a huge challenge. The critical way is to reduce the growth temperature of MOFs in aqueous or ethanol solvents. In the present work, a pressure-assisted room temperature growth strategy was carried out to fabricate continuous and well-intergrown HKUST-1 films on a polymer hollow fiber by using solid copper hydroxide nanostrands as the copper source within 40 min. These HKUST-1 films/polyvinylidenefluoride (PVDF) hollow fiber composite membranes exhibit good separation performance for binary gases with selectivity 116% higher than Knudsen values via both inside-out and outside-in modes. This provides a new way to enable for scale-up preparation of HKUST-1/polymer hollow fiber membranes, due to its superior economic and ecological advantages.

Architecture, component, and microbiome of biofilm involved in the fouling of membrane bioreactors.

PubMed

Inaba, Tomohiro; Hori, Tomoyuki; Aizawa, Hidenobu; Ogata, Atsushi; Habe, Hiroshi

2017-01-01

Biofilm formation on the filtration membrane and the subsequent clogging of membrane pores (called biofouling) is one of the most persistent problems in membrane bioreactors for wastewater treatment and reclamation. Here, we investigated the structure and microbiome of fouling-related biofilms in the membrane bioreactor using non-destructive confocal reflection microscopy and high-throughput Illumina sequencing of 16S rRNA genes. Direct confocal reflection microscopy indicated that the thin biofilms were formed and maintained regardless of the increasing transmembrane pressure, which is a common indicator of membrane fouling, at low organic-loading rates. Their solid components were primarily extracellular polysaccharides and microbial cells. In contrast, high organic-loading rates resulted in a rapid increase in the transmembrane pressure and the development of the thick biofilms mainly composed of extracellular lipids. High-throughput sequencing revealed that the biofilm microbiomes, including major and minor microorganisms, substantially changed in response to the organic-loading rates and biofilm development. These results demonstrated for the first time that the architectures, chemical components, and microbiomes of the biofilms on fouled membranes were tightly associated with one another and differed considerably depending on the organic-loading conditions in the membrane bioreactor, emphasizing the significance of alternative indicators other than the transmembrane pressure for membrane biofouling.

Benefit of computer-aided detection analysis for the detection of subsolid and solid lung nodules on thin- and thick-section CT.

PubMed

Godoy, Myrna C B; Kim, Tae Jung; White, Charles S; Bogoni, Luca; de Groot, Patricia; Florin, Charles; Obuchowski, Nancy; Babb, James S; Salganicoff, Marcos; Naidich, David P; Anand, Vikram; Park, Sangmin; Vlahos, Ioannis; Ko, Jane P

2013-01-01

The objective of our study was to evaluate the impact of computer-aided detection (CAD) on the identification of subsolid and solid lung nodules on thin- and thick-section CT. For 46 chest CT examinations with ground-glass opacity (GGO) nodules, CAD marks computed using thin data were evaluated in two phases. First, four chest radiologists reviewed thin sections (reader(thin)) for nodules and subsequently CAD marks (reader(thin) + CAD(thin)). After 4 months, the same cases were reviewed on thick sections (reader(thick)) and subsequently with CAD marks (reader(thick) + CAD(thick)). Sensitivities were evaluated. Additionally, reader(thick) sensitivity with assessment of CAD marks on thin sections was estimated (reader(thick) + CAD(thin)). For 155 nodules (mean, 5.5 mm; range, 4.0-27.5 mm)-74 solid nodules, 22 part-solid (part-solid nodules), and 59 GGO nodules-CAD stand-alone sensitivity was 80%, 95%, and 71%, respectively, with three false-positives on average (0-12) per CT study. Reader(thin) + CAD(thin) sensitivities were higher than reader(thin) for solid nodules (82% vs 57%, p < 0.001), part-solid nodules (97% vs 81%, p = 0.0027), and GGO nodules (82% vs 69%, p < 0.001) for all readers (p < 0.001). Respective sensitivities for reader(thick), reader(thick) + CAD(thick), reader(thick) + CAD(thin) were 40%, 58% (p < 0.001), and 77% (p < 0.001) for solid nodules; 72%, 73% (p = 0.322), and 94% (p < 0.001) for part-solid nodules; and 53%, 58% (p = 0.008), and 79% (p < 0.001) for GGO nodules. For reader(thin), false-positives increased from 0.64 per case to 0.90 with CAD(thin) (p < 0.001) but not for reader(thick); false-positive rates were 1.17, 1.19, and 1.26 per case for reader(thick), reader(thick) + CAD(thick), and reader(thick) + CAD(thin), respectively. Detection of GGO nodules and solid nodules is significantly improved with CAD. When interpretation is performed on thick sections, the benefit is greater when CAD marks are reviewed on thin rather than thick sections.

A new concept in polymeric thin-film composite nanofiltration membranes with antibacterial properties.

PubMed

Mollahosseini, Arash; Rahimpour, Ahmad

2013-01-01

A new, thin film, biofouling resistant, nanofiltration (NF) membrane was fabricated with two key characteristics, viz. a low rate of silver (Ag) release and long-lasting antibacterial properties. In the new approach, nanoparticles were embedded completely in a polymeric thin-film layer. A comparison was made between the new thin-film composite (TFC), NF membrane and thin-film nanocomposite (TFN), and antibacterial NF membranes. Both types of NF membrane were fabricated by interfacial polymerization on a polysulphone sublayer using m-phenylenediamine and trimesoyl chloride as an amine monomer and an acid chloride monomer, respectively. Energy dispersive X-ray (EDX) microanalysis demonstrated the presence of Ag nanoparticles. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to study the cross-sectional and surface morphological properties of the NF membranes. Permeability and salt rejection were tested using a dead-end filtration cell. Ag leaching from the membranes was measured using inductively coupled mass spectrometry (ICP-MS). Morphological studies showed that the TFC NF membranes had better thin-film formation (a more compact structure and a smoother surface) than TFN NF membranes. Performance experiments on TFC NF membranes revealed that permeability was good, without sacrificing salt rejection. The antibacterial properties of the fabricated membranes were tested using the disk diffusion method and viable plate counts. The antibiofouling properties of the membranes were examined by measuring the quantity of bacterial cells released from the biofilm formed (as a function of the amount of biofilm present). A more sensitive surface was observed compared to that of a typical antibacterial NF membrane. The Ag leaching rates were low, which will likely result in long-lasting antibacterial and biofouling resistant properties.

Modeling Mass and Thermal Transport in Thin Porous Media of PEM Fuel Cells

NASA Astrophysics Data System (ADS)

Konduru, Vinaykumar

Water transport in the Porous Transport Layer (PTL) plays an important role in the efficient operation of polymer electrolyte membrane fuel cells (PEMFC). Excessive water content as well as dry operating conditions are unfavorable for efficient and reliable operation of the fuel cell. The effect of thermal conductivity and porosity on water management are investigated by simulating two-phase flow in the PTL of the fuel cell using a network model. In the model, the PTL consists of a pore-phase and a solid-phase. Different models of the PTLs are generated using independent Weibull distributions for the pore-phase and the solid-phase. The specific arrangement of the pores and solid elements is varied to obtain different PTL realizations for the same Weibull parameters. The properties of PTL are varied by changing the porosity and thermal conductivity. The parameters affecting operating conditions include the temperature, relative humidity in the flow channel and voltage and current density. In addition, a novel high-speed capable Surface Plasmon Resonance (SPR) microscope was built based on Kretschmann's configuration utilizing a collimated Kohler illumination. The SPR allows thin film characterization in a thickness of approximately 0-200nm by measuring the changes in the refractive index. Various independent experiments were run to measure film thickness during droplet coalescence during condensation.

Method for production of ceramic oxide and carbide bodies by polymer inclusion and decomposition

DOEpatents

Quinby, Thomas C.

1985-01-01

A method for the preparation of thin, free-standing metal oxide films which are useful as nuclear accelerator target materials. Cations of any metal except those of Group IA and precious metals, such as, U, Zr, Nd, Ce, Th, pr or Cr, are absorbed on a thin film of polymeric material, such as, carboxymethylcellulose, viscose rayon or cellophane. The cation impregnated polymeric material is dried. Then the impregnated film is heated in an inert atmosphere to form a carbonized membrane. The carbonized membrane is oxidized to yield a thin, self-supporting, metal oxide membrane. Or, the membrane can be heated in an inert atmosphere to yield a thin, self-supporting, metal carbide-containing membrane.

Method for production of ceramic oxide and carbide bodies by polymer inclusion and decomposition

DOEpatents

Quinby, T.C.

1984-08-30

A method for the preparation of thin, free-standing metal oxide films which are useful as nuclear accelerator target materials is described. Cations of any metal except those of Group IA and precious metals, such as, U, Zr, Nd, Ce, Th, Pr or Cr, are absorbed on a thin film of polymeric material, such as carboxymethylcellulose, viscose rayon or cellophane. The cation impregnated polymeric material is dried. Then the impregnated film is heated in an inert atmosphere to form a carbonized membrane. The carbonized membrane is oxidized to yield a thin, self-supporting, metal oxide membrane. Or, the membrane can be heated in an inert atmosphere to yield a thin, self-supporting, metal carbide-containing membrane.

WS2 nanopores for molecule analysis

NASA Astrophysics Data System (ADS)

Danda, Gopinath; Masih Das, Paul; Chou, Yung-Chien; Mlack, Jerome; Naylor, Carl; Perea-Lopez, Nestor; Lin, Zhong; Fulton, Laura Beth; Terrones, Mauricio; Johnson, A. T. Charlie; Drndic, Marija

Atomically thin 2D materials like graphene and transition metal dichalcogenides (TMDs) are interesting as membranes in solid state nanopore sensors for DNA analysis as they may facilitate single base resolution sequencing. These materials also exhibit unique optical and electronic properties which may be exploited to enhance the functionality of nanopore sensors. Here, we report WS2 nanopores, fabricated using a focused TEM beam. We also report their controlled laser-induced expansion in ionic solution. This study demonstrates the possibility of dynamic control of nanopore characteristics optically. NIH Grant R21HG007856, NSF EFRI-1542707.

Film and membrane-model thermodynamics of free thin liquid films.

PubMed

Radke, C J

2015-07-01

In spite of over 7 decades of effort, the thermodynamics of thin free liquid films (as in emulsions and foams) lacks clarity. Following a brief review of the meaning and measurement of thin-film forces (i.e., conjoining/disjoining pressures), we offer a consistent analysis of thin-film thermodynamics. By carefully defining film reversible work, two distinct thermodynamic formalisms emerge: a film model with two zero-volume membranes each of film tension γ(f) and a membrane model with a single zero-volume membrane of membrane tension 2γ(m). In both models, detailed thermodynamic analysis gives rise to thin-film Gibbs adsorption equations that allow calculation of film and membrane tensions from measurements of disjoining-pressure isotherms. A modified Young-Laplace equation arises in the film model to calculate film-thickness profiles from the film center to the surrounding bulk meniscus. No corresponding relation exists in the membrane model. Illustrative calculations of disjoining-pressure isotherms for water are presented using square-gradient theory. We report considerable deviations from Hamaker theory for films less than about 3 nm in thickness. Such thin films are considerably more attractive than in classical Hamaker theory. Available molecular simulations reinforce this finding. Copyright © 2014 Elsevier Inc. All rights reserved.

Hydrophilic nanofibers as new supports for thin film composite membranes for engineered osmosis.

PubMed

Bui, Nhu-Ngoc; McCutcheon, Jeffrey R

2013-02-05

Engineered osmosis (e.g., forward osmosis, pressure-retarded osmosis, direct osmosis) has emerged as a new platform for applications to water production, sustainable energy, and resource recovery. The lack of an adequately designed membrane has been the major challenge that hinders engineered osmosis (EO) development. In this study, nanotechnology has been integrated with membrane science to build a next generation membrane for engineered osmosis. Specifically, hydrophilic nanofiber, fabricated from different blends of polyacrylonitrile and cellulose acetate via electrospinning, was found to be an effective support for EO thin film composite membranes due to its intrinsically wetted open pore structure with superior interconnectivity. The resulting composite membrane exhibits excellent permselectivity while also showing a reduced resistance to mass transfer that commonly impacts EO processes due to its thin, highly porous nanofiber support layer. Our best membrane exhibited a two to three times enhanced water flux and 90% reduction in salt passage when compared to a standard commercial FO membrane. Furthermore, our membrane exhibited one of the lowest structural parameters reported in the open literature. These results indicate that hydrophilic nanofiber supported thin film composite membranes have the potential to be a next generation membrane for engineered osmosis.

Experimental investigation of oily wastewater treatment using combined membrane systems.

PubMed

Salahi, A; Mohammadi, T

2010-01-01

Investigations were carried out for purification of oily wastewater by a combined of ultrafiltration/reverse osmosis (UF/RO) processes. Laboratory-scale UF using polysulfone (PS) and polyacrylonitrile (PAN) membranes were employed with typical oily wastewater collected from API unit of Tehran refinery. The PAN membrane showed higher rejection, more permeation flux and less fouling resistance than the PS membrane. Both membranes produced permeate with oil and grease contents generally less than 5 ppm. Rejection of chemical oxygen demand (COD) and biological oxygen demand (BOD5) were found to be 65% for UF treatment. In this work, Hermia's models were used to investigate the fouling mechanism involved in UF of the oily wastewater. The results showed that the best fit to experimental data corresponds to the cake layer formation model followed by the intermediate blocking model for both the UF membranes. For further treatment of the UF permeates, RO was applied using a thin film composite polyamide membrane. The rejection of COD, BOD5 and total dissolved solid (TDS) after UF/RO treatment increased up to 98%, 98% and 95%, respectively. The results showed that the final permeate has very high quality and even better than that is currently introduced to the cooling towers in Tehran refinery.

Development of Membrane Process for Carbon Dioxide Separation from Diving Atmosphere

DTIC Science & Technology

1990-05-01

backing, or support layer, as is shown in Figure 17b. The ultrathin film and backing of this composite membrane, which is sometimes called a " thin - film ...As a result, the properties and performance of a thin - film laminate can be better controlled, in principle, than those of a "skinned" membrane...method of preparing an asymmetric membrane is by coating a thin nonporous film directly on the surface of a suitable microporous t __ .. NEW DEVELOPMEN"TS

Optimal thickness of silicon membranes to achieve maximum thermoelectric efficiency: A first principles study

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

Mangold, Claudia; Neogi, Sanghamitra; Max Planck Institut für Polymerforschung, Ackermannweg 10, D-55128 Mainz

2016-08-01

Silicon nanostructures with reduced dimensionality, such as nanowires, membranes, and thin films, are promising thermoelectric materials, as they exhibit considerably reduced thermal conductivity. Here, we utilize density functional theory and Boltzmann transport equation to compute the electronic properties of ultra-thin crystalline silicon membranes with thickness between 1 and 12 nm. We predict that an optimal thickness of ∼7 nm maximizes the thermoelectric figure of merit of membranes with native oxide surface layers. Further thinning of the membranes, although attainable in experiments, reduces the electrical conductivity and worsens the thermoelectric efficiency.

Ultra-thin and strong formvar-based membranes with controlled porosity for micro- and nano-scale systems

DOE PAGES

Auchter, Eric Lawrence; Marquez, Justin Ryan; Stevens, Garrison Nicole; ...

2018-03-28

Here, we present a methodology for developing ultra-thin and strong formvar-based membranes with controlled morphologies. Formvar is a thin hydrophilic and oleophilic polymer inert to most chemicals and resistant to radiation. The formvar-based membranes are viable materials as support structures in micro- and macro-scale systems depending on thinness and porosity control. Tunable sub-micron thick porous membranes with 20%–65% porosity were synthesized by controlling the ratios of formvar, glycerol, and chloroform. This synthesis process does not require complex separation or handling methods and allows for the production of strong, thin, and porous formvar-based membranes. An expansive array of these membrane characterizationsmore » including chemical compatibility, mechanical responses, wettability, as well as the mathematical simulations as a function of porosity has been presented. The wide range of chemical compatibility allows for membrane applications in various environments, where other polymers would not be suitable. Our formvar-based membranes were found to have an elastic modulus of 7.8 GPa, a surface free energy of 50 mN m -1 and an average thickness of 125 nm. Stochastic model simulations indicate that formvar with the porosity of ~50% is the optimal membrane formulation, allowing the most material transfer across the membrane while also withstanding the highest simulated pressure loadings before tearing. Development of novel, resilient and versatile membranes with controlled porosity offers a wide range of exciting applications in the fields of nanoscience, microfluidics, and MEMS.« less

Ultra-thin and strong formvar-based membranes with controlled porosity for micro- and nano-scale systems

NASA Astrophysics Data System (ADS)

Auchter, Eric; Marquez, Justin; Stevens, Garrison; Silva, Rebecca; Mcculloch, Quinn; Guengerich, Quintessa; Blair, Andrew; Litchfield, Sebastian; Li, Nan; Sheehan, Chris; Chamberlin, Rebecca; Yarbro, Stephen L.; Dervishi, Enkeleda

2018-05-01

We present a methodology for developing ultra-thin and strong formvar-based membranes with controlled morphologies. Formvar is a thin hydrophilic and oleophilic polymer inert to most chemicals and resistant to radiation. The formvar-based membranes are viable materials as support structures in micro- and macro-scale systems depending on thinness and porosity control. Tunable sub-micron thick porous membranes with 20%–65% porosity were synthesized by controlling the ratios of formvar, glycerol, and chloroform. This synthesis process does not require complex separation or handling methods and allows for the production of strong, thin, and porous formvar-based membranes. An expansive array of these membrane characterizations including chemical compatibility, mechanical responses, wettability, as well as the mathematical simulations as a function of porosity has been presented. The wide range of chemical compatibility allows for membrane applications in various environments, where other polymers would not be suitable. Our formvar-based membranes were found to have an elastic modulus of 7.8 GPa, a surface free energy of 50 mN m‑1 and an average thickness of 125 nm. Stochastic model simulations indicate that formvar with the porosity of ∼50% is the optimal membrane formulation, allowing the most material transfer across the membrane while also withstanding the highest simulated pressure loadings before tearing. Development of novel, resilient and versatile membranes with controlled porosity offers a wide range of exciting applications in the fields of nanoscience, microfluidics, and MEMS.

Ultra-thin and strong formvar-based membranes with controlled porosity for micro- and nano-scale systems

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

Auchter, Eric Lawrence; Marquez, Justin Ryan; Stevens, Garrison Nicole

Here, we present a methodology for developing ultra-thin and strong formvar-based membranes with controlled morphologies. Formvar is a thin hydrophilic and oleophilic polymer inert to most chemicals and resistant to radiation. The formvar-based membranes are viable materials as support structures in micro- and macro-scale systems depending on thinness and porosity control. Tunable sub-micron thick porous membranes with 20%–65% porosity were synthesized by controlling the ratios of formvar, glycerol, and chloroform. This synthesis process does not require complex separation or handling methods and allows for the production of strong, thin, and porous formvar-based membranes. An expansive array of these membrane characterizationsmore » including chemical compatibility, mechanical responses, wettability, as well as the mathematical simulations as a function of porosity has been presented. The wide range of chemical compatibility allows for membrane applications in various environments, where other polymers would not be suitable. Our formvar-based membranes were found to have an elastic modulus of 7.8 GPa, a surface free energy of 50 mN m -1 and an average thickness of 125 nm. Stochastic model simulations indicate that formvar with the porosity of ~50% is the optimal membrane formulation, allowing the most material transfer across the membrane while also withstanding the highest simulated pressure loadings before tearing. Development of novel, resilient and versatile membranes with controlled porosity offers a wide range of exciting applications in the fields of nanoscience, microfluidics, and MEMS.« less

Speckle-interferometric measurement system of 3D deformation to obtain thickness changes of thin specimen under tensile loads

NASA Astrophysics Data System (ADS)

Kowarsch, Robert; Zhang, Jiajun; Sguazzo, Carmen; Hartmann, Stefan; Rembe, Christian

2017-06-01

The analysis of materials and geometries in tensile tests and the extraction of mechanic parameters is an important field in solid mechanics. Especially the measurement of thickness changes is important to obtain accurate strain information of specimens under tensile loads. Current optical measurement methods comprising 3D digital image correlation enable thickness-change measurement only with nm-resolution. We present a phase-shifting electronic speckle-pattern interferometer in combination with speckle-correlation technique to measure the 3D deformation. The phase-shift for the interferometer is introduced by fast wavelength tuning of a visible diode laser by injection current. In a post-processing step, both measurements can be combined to reconstruct the 3D deformation. In this contribution, results of a 3Ddeformation measurement for a polymer membrane are presented. These measurements show sufficient resolution for the detection of 3D deformations of thin specimen in tensile test. In future work we address the thickness changes of thin specimen under tensile loads.

From viscous to elastic sheets: Dynamics of smectic freely floating films

NASA Astrophysics Data System (ADS)

Stannarius, Ralf; Harth, Kirsten; May, Kathrin; Trittel, Torsten

The dynamics of droplets and bubbles, particularly on microscopic scales, are of considerable importance in biological, environmental, and technical contexts. Soap bubbles, vesicles and components of biological cells are well known examples where the dynamic behavior is significantly influenced by the properties of thin membranes enclosed by fluids. Two-dimensional membrane motions couple to 3D shape transformations. Smectic liquid crystal mesogens form phases with internal molecular layer order. Free-standing films are easily prepared from this class of materials. They represent simple model systems for membrane dynamics and pattern formation in a quasi two-dimensional fluid. These films are usually spanned over a frame, and they can be inflated to bubbles on a support. Recently, closed microscopic shells of liquid-crystalline materials suspended in an outer fluid without contact to a solid support have been introduced and studied. With a special technique, we prepare millimetre to centimetre sized smectic bubbles in air (similar to soap bubbles). Their distinct feature is the fact that any change of surface area is coupled to a restructuring of the layers in the membrane. High-speed cameras are used to observe the shape transformations of freely floating bubbles from a distorted initial shape to a sphere. Bursting dynamics are recorded and compared to models. Most strikingly, an unpreceded cross-over from inviscid to viscous and elastic behaviour with increasing thickness of the membrane is found: Whereas thin bubbles behave almost like inviscid fluids, the relaxation dynamics slows down considerably for larger film thicknesses. Surface wrinkling and formation of extrusions are observed. We will present a characterization and an expalantion for the above phenomena.

A strip-shield improves the efficiency of a solenoid coil in probes for high-field solid-state NMR of lossy biological samples.

PubMed

Wu, Chin H; Grant, Christopher V; Cook, Gabriel A; Park, Sang Ho; Opella, Stanley J

2009-09-01

A strip-shield inserted between a high inductance double-tuned solenoid coil and the glass tube containing the sample improves the efficiency of probes used for high-field solid-state NMR experiments on lossy aqueous samples of proteins and other biopolymers. A strip-shield is a coil liner consisting of thin copper strips layered on a PTFE (polytetrafluoroethylene) insulator. With lossy samples, the shift in tuning frequency is smaller, the reduction in Q, and RF-induced heating are all significantly reduced when the strip-shield is present. The performance of 800MHz (1)H/(15)N and (1)H/(13)C double-resonance probes is demonstrated on aqueous samples of membrane proteins in phospholipid bilayers.

Solid state oxygen anion and electron mediating membrane and catalytic membrane reactors containing them

DOEpatents

Schwartz, Michael; White, James H.; Sammells, Anthony F.

2005-09-27

This invention relates to gas-impermeable, solid state materials fabricated into membranes for use in catalytic membrane reactors. This invention particularly relates to solid state oxygen anion- and electron-mediating membranes for use in catalytic membrane reactors for promoting partial or full oxidation of different chemical species, for decomposition of oxygen-containing species, and for separation of oxygen from other gases. Solid state materials for use in the membranes of this invention include mixed metal oxide compounds having the brownmillerite crystal structure.

Solid state oxygen anion and electron mediating membrane and catalytic membrane reactors containing them

DOEpatents

Schwartz, Michael; White, James H.; Sammels, Anthony F.

2000-01-01

This invention relates to gas-impermeable, solid state materials fabricated into membranes for use in catalytic membrane reactors. This invention particularly relates to solid state oxygen anion- and electron-mediating membranes for use in catalytic membrane reactors for promoting partial or full oxidation of different chemical species, for decomposition of oxygen-containing species, and for separation of oxygen from other gases. Solid state materials for use in the membranes of this invention include mixed metal oxide compounds having the brownmillerite crystal structure.

The Urethral Rhabdosphincter, Levator Ani Muscle, and Perineal Membrane: A Review

PubMed Central

Hinata, Nobuyuki; Murakami, Gen

2014-01-01

Detailed knowledge of the anatomy of the rhabdosphincter and adjacent tissues is mandatory during urologic surgery to ensure reliable oncologic and functional outcomes. To characterize the levator ani (LA) function for the urethral sphincter, we described connective tissue morphology between the LA and urethral rhabdosphincter. The interface tissue between the LA and rhabdosphincter area in males contained abundant irregularly arrayed elastic fibers and smooth muscles. The male rhabdosphincter was positioned alongside the LA to divide the elevation force and not in-series along the axis of LA contraction. The male perineal membrane was thin but solid and extends along the inferior margin or bottom of the rhabdosphincter area. In contrast, the female rhabdosphincter, including the compressor urethrae and urethrovaginal sphincter muscles, was embedded in the elastic fiber mesh that is continuous with the thick, multilaminar perineal membrane. The inferomedial edge of the female LA was attached to the upper surface of the perineal membrane and not directly attached to the rhabdosphincter. We presented new diagrams showing the gender differences in topographical anatomy of the LA and rhabdosphincter. PMID:24877147

Membrane catalyst layer for fuel cells

DOEpatents

Wilson, Mahlon S.

1993-01-01

A gas reaction fuel cell incorporates a thin catalyst layer between a solid polymer electrolyte (SPE) membrane and a porous electrode backing. The catalyst layer is preferably less than about 10 .mu.m in thickness with a carbon supported platinum catalyst loading less than about 0.35 mgPt/cm.sup.2. The film is formed as an ink that is spread and cured on a film release blank. The cured film is then transferred to the SPE membrane and hot pressed into the surface to form a catalyst layer having a controlled thickness and catalyst distribution. Alternatively, the catalyst layer is formed by applying a Na.sup.+ form of a perfluorosulfonate ionomer directly to the membrane, drying the film at a high temperature, and then converting the film back to the protonated form of the ionomer. The layer has adequate gas permeability so that cell performance is not affected and has a density and particle distribution effective to optimize proton access to the catalyst and electronic continuity for electron flow from the half-cell reaction occurring at the catalyst.

First report of vertically aligned (Sn,Ir)O2:F solid solution nanotubes: Highly efficient and robust oxygen evolution electrocatalysts for proton exchange membrane based water electrolysis

NASA Astrophysics Data System (ADS)

Ghadge, Shrinath Dattatray; Patel, Prasad P.; Datta, Moni K.; Velikokhatnyi, Oleg I.; Shanthi, Pavithra M.; Kumta, Prashant N.

2018-07-01

One dimensional (1D) vertically aligned nanotubes (VANTs) of (Sn0.8Ir0.2)O2:10F are synthesized for the first time by a sacrificial template assisted approach. The aim is to enhance the electrocatalytic activity of F doped (Sn,Ir)O2 solid solution electrocatalyst for oxygen evolution reaction (OER) in proton exchange membrane (PEM) based water electrolysis by generating (Sn0.8Ir0.2)O2:10F nanotubes (NTs). The 1D vertical channels and the high electrochemically active surface area (ECSA ∼38.46 m2g-1) provide for facile electron transport. This results in low surface charge transfer resistance (4.2 Ω cm2), low Tafel slope (58.8 mV dec-1) and excellent electrochemical OER performance with ∼2.3 and ∼2.6 fold higher electrocatalytic activity than 2D thin films of (Sn0.8Ir0.2)O2:10F and benchmark IrO2 electrocatalysts, respectively. Furthermore, (Sn0.8Ir0.2)O2:10F NTs exhibit excellent mass activity (21.67 A g-1), specific activity (0.0056 mAcm-2) and TOF (0.016 s-1), which is ∼2-2.6 fold higher than thin film electrocatalysts at an overpotential of 270 mV, with a total mass loading of 0.3 mg cm-2. In addition, (Sn0.8Ir0.2)O2:10F NTs demonstrate remarkable electrochemical durability - comparable to thin films of (Sn0.8Ir0.2)O2:10F and pure IrO2, operated under identical testing conditions in PEM water electrolysis. These results therefore indicate promise of (Sn0.8Ir0.2)O2:10F NTs as OER electrocatalysts for efficient and sustainable hydrogen production.

Multifunctional flexible free-standing titanate nanobelt membranes as efficient sorbents for the removal of radioactive 90Sr2+ and 137Cs+ ions and oils

NASA Astrophysics Data System (ADS)

Wen, Tao; Zhao, Zhiwei; Shen, Congcong; Li, Jiaxing; Tan, Xiaoli; Zeb, Akif; Wang, Xiangke; Xu, An-Wu

2016-02-01

For the increasing attention focused on saving endangered environments, there is a growing need for developing membrane materials able to perform complex functions such as removing radioactive pollutants and oil spills from water. A major challenge is the scalable fabrication of membranes with good mechanical and thermal stability, superior resistance to radiation, and excellent recyclability. In this study, we constructed a multifunctional flexible free-standing sodium titanate nanobelt (Na-TNB) membrane that was assembled as advanced radiation-tainted water treatment and oil uptake. We compared the adsorption behavior of 137Cs+ and 90Sr2+ on Na-TNB membranes under various environmental conditions. The maximum adsorption coefficient value (Kd) for Sr2+ reaches 107 mL g-1. The structural collapse of the exchange materials were confirmed by XRD, FTIR and XPS spectroscopy as well as Raman analysis. The adsorption mechanism of Na-TNB membrane is clarified by forming a stable solid with the radioactive cations permanently trapped inside. Besides, the engineered multilayer membrane is exceptionally capable in selectively and rapidly adsorbing oils up to 23 times the adsorbent weight when coated with a thin layer of hydrophobic molecules. This multifunctional membrane has exceptional potential as a suitable material for next generation water treatment and separation technologies.

Nanofiber based triple layer hydro-philic/-phobic membrane - a solution for pore wetting in membrane distillation

PubMed Central

Prince, J. A.; Rana, D.; Matsuura, T.; Ayyanar, N.; Shanmugasundaram, T. S.; Singh, G.

2014-01-01

The innovative design and synthesis of nanofiber based hydro-philic/phobic membranes with a thin hydro-phobic nanofiber layer on the top and a thin hydrophilic nanofiber layer on the bottom of the conventional casted micro-porous layer which opens up a solution for membrane pore wetting and improves the pure water flux in membrane distillation. PMID:25377488

Brazing method

DOEpatents

McCormick, James T.; Ferry, Paul B.; Hall, John C.

1981-10-06

There is disclosed a positive cathode electrode structure formed by brazing a thin porous membrane to a backing material by preselecting a predetermined area of the thin porous membrane and thereafter providing a braze flow barrier throughout the remainder of the membrane and electrolessly plating a nickel-phosphide alloy on the backing material, or in this case the honeycomb structure. The preselected area of the thin porous membrane is placed in intimate contact with the electrolessly plated portion of the backing material and heated to elevated temperatures in the absence of oxygen to form a brazed joint limited to a preselected area. If the braze flow barrier is provided by application of a liquid organic solvent, then the organic solvent is driven off by maintaining the thin porous membrane at elevated temperatures for an extended period of time prior to the brazing operation.

Long-wave dynamics of an elastic sheet lubricated by a thin liquid film on a wetting substrate

NASA Astrophysics Data System (ADS)

Young, Y.-N.; Stone, H. A.

2017-06-01

The dynamics of an elastic sheet lubricated by a thin liquid film on a wetting solid substrate is examined using both numerical simulations of a long-wave lubrication equation and a quasistatic model. Interactions between the liquid and the wetting substrate are modeled by a disjoining pressure that gives rise to an ultrathin (precursor) film. For a fluid interface without elastic bending stiffness, a flat precursor film may be linearly unstable and evolve towards an equilibrium of a single "drop" connected to a flat ultrathin film. Similar behavior is found when the thin film is covered by an elastic sheet: The sheet deforms, rearranging the thin liquid film, and contributes regulating surface forces such as a bending resistance and/or a tensile force, which may arise from interactions between the sheet and liquid or inextensibility of the sheet. Glasner's quasistatic model [Phys. Fluids 15, 1837 (2003), 10.1063/1.1578076], developed for a liquid film, is adopted to investigate the combined effects of elastic and tensile forces in the sheet on the thin film dynamics. The equilibrium height of the drop is found to vary inversely with the bending rigidity. When the elastic sheet is inextensible (such as a lipid bilayer membrane), a compressive tensile force may occur and the equilibrium film height is dependent less on the bending rigidity and more on the excess area of the membrane. Analyses of the lubrication equation also show that the precursor film transitions monotonically to the core film for tension-dominated dynamics. In contrast, for elasticity-dominated dynamics, a spatial oscillation of film height in the contact line region is found. In addition, elasticity in the sheet causes a sliding motion of the thin film: the contact angle is rendered zero by elasticity, and the contact line moves at a finite speed.

Bioinspired model of mechanical energy harvesting based on flexoelectric membranes.

PubMed

Rey, Alejandro D; Servio, P; Herrera-Valencia, E E

2013-02-01

Membrane flexoelectricity is an electromechanical coupling process that describes membrane electrical polarization due to bending and membrane bending under electric fields. In this paper we propose, formulate, and characterize a mechanical energy harvesting system consisting of a deformable soft flexoelectric thin membrane subjected to harmonic forcing from contacting bulk fluids. The key elements of the energy harvester are formulated and characterized, including (i) the mechanical-to-electrical energy conversion efficiency, (ii) the electromechanical shape equation connecting fluid forces with membrane curvature and electric displacement, and (iii) the electric power generation and efficiency. The energy conversion efficiency is cast as the ratio of flexoelectric coupling to the product of electric and bending elasticity. The device is described by a second-order curvature dynamics coupled to the electric displacement equation and as such results in mechanical power absorption with a resonant peak whose amplitude decreases with bending viscosity. The electric power generation is proportional to the conversion factor and the power efficiency decreases with frequency. Under high bending viscosity, the power efficiency increases with the conversion factor and under low viscosities it decreases with the conversion factor. The theoretical results presented contribute to the ongoing experimental efforts to develop mechanical energy harvesting from fluid flow energy through solid-fluid interactions and electromechanical transduction.

Electrochemically Switchable Polymeric Membrane Ion-Selective Electrodes.

PubMed

Zdrachek, Elena; Bakker, Eric

2018-06-07

We present here for the first time a solid contact ion-selective electrode suitable for the simultaneous sensing of cations (tetrabutylammonium) and anions (hexafluorophosphate), achieved by electrochemical switching. The membrane is based on a thin plasticized polyurethane membrane deposited on poly(3-octylthiophene) (POT) and contains a cation exchanger and lipophilic electrolyte (ETH 500). The cation exchanger is initially in excess; the ion-selective electrode exhibits an initial potentiometric response to cations. During an oxidative current pulse, POT is converted into POT + , which results in the expulsion of cations from the membrane followed by the extraction of anions from the sample solution to fulfill the electroneutrality condition. This creates a defined excess of lipophilic cation in the membrane, resulting in a potentiometric anion response. A reductive current pulse restores the original cation response by triggering the conversion of POT + back into POT, which is accompanied by the expulsion of anions from the membrane and the extraction of cations from the sample solution. Various current pulse magnitudes and durations are explored, and the best results in terms of response slope values and signal stability were observed with an oxidation current pulse of 140 μA cm -2 applied for 8 s and a reduction current pulse of -71 μA cm -2 applied for 8 s.

Formation of a freely suspended membrane via a combination of interfacial reaction and wetting.

PubMed

McNamee, Cathy E; Jaumann, Manfred; Möller, Martin; Ding, Ailin; Hemeltjen, Steffen; Ebert, Susanne; Baumann, Wolfgang; Goedel, Werner A

2005-11-08

Applying poly(ethoxysiloxane) (a liquid non-water-soluble polymer that can be hydrolyzed and cross-linked by diluted acids) to an air/pH 1 water interface gave rise to thin homogeneous solid layers. These layers were strong enough to be transferable to electron microscopy grids with holes of dimensions up to 150 microm and covered the holes as freely suspended membranes. No homogeneous layers were formed at an air/pH 5 water interface. Brewster angle microscopy images show that the poly(ethoxysiloxane) is not spontaneously forming a wetting layer on water. It initially forms lenses, which slowly spread out within several hours. We conclude that the spreading occurs simultaneously with the hydrolysis and cross-linking of the poly(ethoxysiloxane) and that the reaction products finally assist the complete wetting of the water surface.

Electrochemical Reduction of Dissolved Oxygen in Alkaline, Solid Polymer Electrolyte Films.

PubMed

Novitski, David; Kosakian, Aslan; Weissbach, Thomas; Secanell, Marc; Holdcroft, Steven

2016-11-30

Mass transport of oxygen through an ionomer contained within the cathode catalyst layer in an anion exchange membrane fuel cell is critical for a functioning fuel cell, yet is relatively unexplored. Moreover, because water is a reactant in the oxygen reduction reaction (ORR) in alkaline media, an adequate supply of water is required. In this work, ORR mass transport behavior is reported for methylated hexamethyl-p-terphenyl polymethylbenzimidazoles (HMT-PMBI), charge balanced by hydroxide ions (IEC from 2.1 to 2.5 mequiv/g), and commercial Fumatec FAA-3 membranes. Electrochemical mass transport parameters are determined by potential step chronoamperometry using a Pt microdisk solid-state electrochemical cell, in air at 60 °C, with relative humidity controlled between 70% and 98%. The oxygen diffusion coefficient (D bO2 ), oxygen concentration (c bO2 ), and oxygen permeability (D bO2 ·c bO2 ) were obtained by nonlinear curve fitting of the current transients using the Shoup-Szabo equation. Mass transport parameters are correlated to water content of the ionomer membrane. It is found that the oxygen diffusion coefficients decreased by 2 orders of magnitude upon reducing the water content of the ionomer membrane by lowering the relative humidity. The limitation of the Shoup-Szabo equation for extracting ORR mass transport parameters using thin ionomer films was evaluated by numerical modeling of the current transients, which revealed that a significant discrepancy (up to 29% under present conditions) was evident for highly hydrated membranes for which the oxygen diffusion coefficient was largest, and in which the oxygen depletion region reached the ionomer/gas interface during the chronoamperometric analysis.

A stable planar bilayer membrane of phospholipid supported by cellulose sheets.

PubMed

Setaka, M; Yamamoto, T; Sato, N; Yano, M; Kwan, T

1982-01-01

A new method is reported for preparing a thin planar membrane of 1,2-distearoylsn-glycero-3-phosphocholine and egg yolk lecithin-cholesterol (molar ratio of 1:1) between a pair of cellulose sheets. This technique, developed from the method of the multilayer planar membrane preparation (Setaka, M., et al. (1979) J. Biochem. 86, 355-362; 1619-1622; (1980) J. Biochem. 88, 1819-1829), consisted of three experimental processes. First, a phospholipid monolayer was prepared at an air-water interface, then taken up on a stretched cellulose sheet. A thin lipid membrane, supported from both sides by cellulose sheets, was constructed by combining two of these lipid monolayer-cellulose sheets. The permeability coefficient of the thin lipid membrane was estimated by removing the effect of two outer cellulose sheets, and this permeability was found to be larger than those of other model membranes of a lipid bilayer, indicating that the present lipid membrane is not a perfect single lipid bilayer. However, certain experimental evidence suggests that the bulk of the phospholipids formed a bilayer between the two cellulose sheets. Since this lipid membrane is particularily stable, larger membranes can be prepared by the present method than other planar bilayer membranes of lipid, which are usually constructed inside a pin hole in a thin teflon sheet.

Wrinkle-free design of thin membrane structures using stress-based topology optimization

NASA Astrophysics Data System (ADS)

Luo, Yangjun; Xing, Jian; Niu, Yanzhuang; Li, Ming; Kang, Zhan

2017-05-01

Thin membrane structures would experience wrinkling due to local buckling deformation when compressive stresses are induced in some regions. Using the stress criterion for membranes in wrinkled and taut states, this paper proposed a new stress-based topology optimization methodology to seek the optimal wrinkle-free design of macro-scale thin membrane structures under stretching. Based on the continuum model and linearly elastic assumption in the taut state, the optimization problem is defined as to maximize the structural stiffness under membrane area and principal stress constraints. In order to make the problem computationally tractable, the stress constraints are reformulated into equivalent ones and relaxed by a cosine-type relaxation scheme. The reformulated optimization problem is solved by a standard gradient-based algorithm with the adjoint-variable sensitivity analysis. Several examples with post-bulking simulations and experimental tests are given to demonstrate the effectiveness of the proposed optimization model for eliminating stress-related wrinkles in the novel design of thin membrane structures.

Alternative synthetic approaches for metal-organic frameworks: transformation from solid matters.

PubMed

Zhan, Guowu; Zeng, Hua Chun

2016-12-20

Developing economic and sustainable synthetic strategies for metal-organic frameworks (MOFs) is imperative for promoting MOF materials into large scale industrial use. Very recently, an alternative strategy for MOF synthesis by using solvent-insoluble "solid matters" as cation reservoirs and/or templates has been developed to accomplish this goal, in which the solid matters often refer to metals, metal oxides, hydroxides, carbonates, and so forth, but excluding the soluble metal salts which have been prevailingly used in MOF synthesis. Although most of the pioneering activities in this field have just started in the past 5 years, remarkable achievements have been made covering the synthesis, functionalization, positioning, and applications. A great number of MOFs in powder form, thin-films, or membranes, have been prepared through such solid-to-MOF transformations. This field is rapidly developing and expanding, and the number of related scientific publications has strikingly increased over the last few years. The aim of this review is to summarise the latest developments, highlight the present state-of-the-art, and also provide an overview for future research directions.

Fuel cell with interdigitated porous flow-field

DOEpatents

Wilson, Mahlon S.

1997-01-01

A polymer electrolyte membrane (PEM) fuel cell is formed with an improved system for distributing gaseous reactants to the membrane surface. A PEM fuel cell has an ionic transport membrane with opposed catalytic surfaces formed thereon and separates gaseous reactants that undergo reactions at the catalytic surfaces of the membrane. The fuel cell may also include a thin gas diffusion layer having first and second sides with a first side contacting at least one of the catalytic surfaces. A macroporous flow-field with interdigitated inlet and outlet reactant channels contacts the second side of the thin gas diffusion layer for distributing one of the gaseous reactants over the thin gas diffusion layer for transport to an adjacent one of the catalytic surfaces of the membrane. The porous flow field may be formed from a hydrophilic material and provides uniform support across the backside of the electrode assembly to facilitate the use of thin backing layers.

Fuel cell with interdigitated porous flow-field

DOEpatents

Wilson, M.S.

1997-06-24

A polymer electrolyte membrane (PEM) fuel cell is formed with an improved system for distributing gaseous reactants to the membrane surface. A PEM fuel cell has an ionic transport membrane with opposed catalytic surfaces formed thereon and separates gaseous reactants that undergo reactions at the catalytic surfaces of the membrane. The fuel cell may also include a thin gas diffusion layer having first and second sides with a first side contacting at least one of the catalytic surfaces. A macroporous flow-field with interdigitated inlet and outlet reactant channels contacts the second side of the thin gas diffusion layer for distributing one of the gaseous reactants over the thin gas diffusion layer for transport to an adjacent one of the catalytic surfaces of the membrane. The porous flow field may be formed from a hydrophilic material and provides uniform support across the backside of the electrode assembly to facilitate the use of thin backing layers. 9 figs.

Emissivity of freestanding membranes with thin metal coatings

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

Zwol, P. J. van, E-mail: Pieter-jan.van.zwol@asml.com; Vles, D. F.; Voorthuijzen, W. P.

Freestanding silicon nitride membranes with thicknesses down to a few tens of nanometers find use as TEM windows or soft X-ray spectral purity filters. As the thickness of a membrane decreases, emissivity vanishes, which limits radiative heat emission and resistance to heat loads. We show that thin metal layers with thicknesses in the order of 1 nm enhance the emissivity of thin membranes by two to three orders of magnitude close to the theoretical limit of 0.5. This considerably increases thermal load capacity of membranes in vacuum environments. Our experimental results are in line with classical theory in which we adaptmore » thickness dependent scattering terms in the Drude and Lorentz oscillators.« less

Free-Standing and Transparent Graphene Membrane of Polyhedron Box-Shaped Basic Building Units Directly Grown Using a NaCl Template for Flexible Transparent and Stretchable Solid-State Supercapacitors.

PubMed

Li, Na; Yang, Gongzheng; Sun, Yong; Song, Huawei; Cui, Hao; Yang, Guowei; Wang, Chengxin

2015-05-13

Transparency has never been integrated into freestanding flexible graphene paper (FF-GP), although FF-GP has been discussed extensively, because a thin transparent graphene sheet will fracture easily when the template or substrate is removed using traditional methods. Here, transparent FF-GP (FFT-GP) was developed using NaCl as the template and was applied in transparent and stretchable supercapacitors. The capacitance was improved by nearly 1000-fold compared with that of the laminated or wrinkled chemical vapor deposition graphene-film-based supercapacitors.

A review on polyamide thin film nanocomposite (TFN) membranes: History, applications, challenges and approaches.

PubMed

Lau, W J; Gray, Stephen; Matsuura, T; Emadzadeh, D; Chen, J Paul; Ismail, A F

2015-09-01

This review focuses on the development of polyamide (PA) thin film nanocomposite (TFN) membranes for various aqueous media-based separation processes such as nanofiltration, reverse osmosis and forward osmosis since the concept of TFN was introduced in year 2007. Although the total number of published TFN articles falls far short of the articles of the well-known thin film composite (TFC) membranes, its growth rate is significant, particularly since 2012. Generally, by incorporating an appropriate amount of nanofiller into a thin selective PA layer of a composite membrane, one could produce TFN membranes with enhanced separation characteristics as compared to the conventional TFC membrane. For certain cases, the resulting TFN membranes demonstrate not only excellent antifouling resistance and/or greater antibacterial effect, but also possibly overcome the trade-off effect between water permeability and solute selectivity. Furthermore, this review attempts to give the readers insights into the difficulties of incorporating inorganic nanomaterials into the organic PA layer whose thickness usually falls in a range of several-hundred nanometers. It is also intended to show new possible approaches to overcome these challenges in TFN membrane fabrication. Copyright © 2015 Elsevier Ltd. All rights reserved.

On the mechanics of growing thin biological membranes

NASA Astrophysics Data System (ADS)

Rausch, Manuel K.; Kuhl, Ellen

2014-02-01

Despite their seemingly delicate appearance, thin biological membranes fulfill various crucial roles in the human body and can sustain substantial mechanical loads. Unlike engineering structures, biological membranes are able to grow and adapt to changes in their mechanical environment. Finite element modeling of biological growth holds the potential to better understand the interplay of membrane form and function and to reliably predict the effects of disease or medical intervention. However, standard continuum elements typically fail to represent thin biological membranes efficiently, accurately, and robustly. Moreover, continuum models are typically cumbersome to generate from surface-based medical imaging data. Here we propose a computational model for finite membrane growth using a classical midsurface representation compatible with standard shell elements. By assuming elastic incompressibility and membrane-only growth, the model a priori satisfies the zero-normal stress condition. To demonstrate its modular nature, we implement the membrane growth model into the general-purpose non-linear finite element package Abaqus/Standard using the concept of user subroutines. To probe efficiently and robustness, we simulate selected benchmark examples of growing biological membranes under different loading conditions. To demonstrate the clinical potential, we simulate the functional adaptation of a heart valve leaflet in ischemic cardiomyopathy. We believe that our novel approach will be widely applicable to simulate the adaptive chronic growth of thin biological structures including skin membranes, mucous membranes, fetal membranes, tympanic membranes, corneoscleral membranes, and heart valve membranes. Ultimately, our model can be used to identify diseased states, predict disease evolution, and guide the design of interventional or pharmaceutic therapies to arrest or revert disease progression.

On the mechanics of growing thin biological membranes

PubMed Central

Rausch, Manuel K.; Kuhl, Ellen

2013-01-01

Despite their seemingly delicate appearance, thin biological membranes fulfill various crucial roles in the human body and can sustain substantial mechanical loads. Unlike engineering structures, biological membranes are able to grow and adapt to changes in their mechanical environment. Finite element modeling of biological growth holds the potential to better understand the interplay of membrane form and function and to reliably predict the effects of disease or medical intervention. However, standard continuum elements typically fail to represent thin biological membranes efficiently, accurately, and robustly. Moreover, continuum models are typically cumbersome to generate from surface-based medical imaging data. Here we propose a computational model for finite membrane growth using a classical midsurface representation compatible with standard shell elements. By assuming elastic incompressibility and membrane-only growth, the model a priori satisfies the zero-normal stress condition. To demonstrate its modular nature, we implement the membrane growth model into the general-purpose non-linear finite element package Abaqus/Standard using the concept of user subroutines. To probe efficiently and robustness, we simulate selected benchmark examples of growing biological membranes under different loading conditions. To demonstrate the clinical potential, we simulate the functional adaptation of a heart valve leaflet in ischemic cardiomyopathy. We believe that our novel approach will be widely applicable to simulate the adaptive chronic growth of thin biological structures including skin membranes, mucous membranes, fetal membranes, tympanic membranes, corneoscleral membranes, and heart valve membranes. Ultimately, our model can be used to identify diseased states, predict disease evolution, and guide the design of interventional or pharmaceutic therapies to arrest or revert disease progression. PMID:24563551

MultiLayer solid electrolyte for lithium thin film batteries

DOEpatents

Lee, Se -Hee; Tracy, C. Edwin; Pitts, John Roland; Liu, Ping

2015-07-28

A lithium metal thin-film battery composite structure is provided that includes a combination of a thin, stable, solid electrolyte layer [18] such as Lipon, designed in use to be in contact with a lithium metal anode layer; and a rapid-deposit solid electrolyte layer [16] such as LiAlF.sub.4 in contact with the thin, stable, solid electrolyte layer [18]. Batteries made up of or containing these structures are more efficient to produce than other lithium metal batteries that use only a single solid electrolyte. They are also more resistant to stress and strain than batteries made using layers of only the stable, solid electrolyte materials. Furthermore, lithium anode batteries as disclosed herein are useful as rechargeable batteries.

Dynamic nuclear polarization methods in solids and solutions to explore membrane proteins and membrane systems.

PubMed

Cheng, Chi-Yuan; Han, Songi

2013-01-01

Membrane proteins regulate vital cellular processes, including signaling, ion transport, and vesicular trafficking. Obtaining experimental access to their structures, conformational fluctuations, orientations, locations, and hydration in membrane environments, as well as the lipid membrane properties, is critical to understanding their functions. Dynamic nuclear polarization (DNP) of frozen solids can dramatically boost the sensitivity of current solid-state nuclear magnetic resonance tools to enhance access to membrane protein structures in native membrane environments. Overhauser DNP in the solution state can map out the local and site-specific hydration dynamics landscape of membrane proteins and lipid membranes, critically complementing the structural and dynamics information obtained by electron paramagnetic resonance spectroscopy. Here, we provide an overview of how DNP methods in solids and solutions can significantly increase our understanding of membrane protein structures, dynamics, functions, and hydration in complex biological membrane environments.

A Novel Fabrication Approach for Multifunctional Graphene-based Thin Film Nano-composite Membranes with Enhanced Desalination and Antibacterial Characteristics.

PubMed

Hegab, Hanaa M; ElMekawy, Ahmed; Barclay, Thomas G; Michelmore, Andrew; Zou, Linda; Losic, Dusan; Saint, Christopher P; Ginic-Markovic, Milena

2017-08-08

A practical fabrication technique is presented to tackle the trade-off between the water flux and salt rejection of thin film composite (TFC) reverse osmosis (RO) membranes through controlled creation of a thinner active selective polyamide (PA) layer. The new thin film nano-composite (TFNC) RO membranes were synthesized with multifunctional poly tannic acid-functionalized graphene oxide nanosheets (pTA-f-GO) embedded in its PA thin active layer, which is produced through interfacial polymerization. The incorporation of pTA-f-GOL into the fabricated TFNC membranes resulted in a thinner PA layer with lower roughness and higher hydrophilicity compared to pristine membrane. These properties enhanced both the membrane water flux (improved by 40%) and salt rejection (increased by 8%) of the TFNC membrane. Furthermore, the incorporation of biocidal pTA-f-GO nanosheets into the PA active layer contributed to improving the antibacterial properties by 80%, compared to pristine membrane. The fabrication of the pTA-f-GO nanosheets embedded in the PA layer presented in this study is a very practical, scalable and generic process that can potentially be applied in different types of separation membranes resulting in less energy consumption, increased cost-efficiency and improved performance.

Propagation of a viscous thin film over an elastic membran

NASA Astrophysics Data System (ADS)

Zheng, Zhong; Griffiths, Ian; Stone, Howard

2016-11-01

We study the buoyancy-driven spreading of a thin viscous film over a thin elastic membrane. Neglecting the effects of membrane bending and the membrane weight, we study the case of constant fluid injection and obtain a system of coupled partial differential equations to describe the shape of the air-liquid interface, and the deformation and the radial tension of the stretched membrane. We obtain self-similar solutions to describe the dynamics. In particular, in the early time period, the dynamics is dominated by buoyancy-driven spreading of the liquid film, and membrane stretching is a response to the buoyancy-controlled distribution of liquid weight; the location of the liquid front obeys the power-law form rf (t) t 1 / 2 . However, in the late time period, the system is quasi-steady, the air-liquid interface is flat, and membrane stretching, due to the liquid weight, causes the spreading of the liquid front; the location of the front obeys a different power-law form rf (t) t 1 / 4 before the edge effects of the membrane become significant. In addition, we report laboratory experiments for constant fluid injection using different viscous liquids and thin elastic membranes. Very good agreement is obtained between the theory and experiments.

Single Protein Structural Analysis with a Solid-state Nanopore Sensor

NASA Astrophysics Data System (ADS)

Li, Jiali; Golovchenko, Jene; McNabb, David

2005-03-01

We report on the use of solid-state nanopore sensors to detect single polypeptides. These solid-state nanopores are fabricated in thin membranes of silicon nitride by ion beam sculpting...[1]. When an electrically biased nanopore is exposed to denatured proteins in ionic solution, discrete transient electronic signals: current blockages are observed. We demonstrate examples of such transient electronic signals for Bovine Serum Albumin (BSA) and human placental laminin M proteins in Guanidine hydrochloride solution, which suggest that these polypeptides are individually translocating through the nanopore during the detecting process. The amplitude of the current blockages is proportional to the bias voltage. No transient current blockages are observed when proteins are not present in the solution. To probe protein-folding state, pH and temperature dependence experiments are performed. The results demonstrate a solid-state nanopore sensor can be used to detect and analyze single polypeptide chains. Similarities and differences with signals obtained from double stranded DNA in a solid-state nanopore and single stranded DNA in a biological nanopore are discussed. [.1] Li, J., D. Stein, C. McMullan, D. Branton, M.J. Aziz, and J.A. Golovchenko, Ion-beam sculpting at nanometre length scales. Nature, 2001. 412(12 July): p. 166-169.

Spectroscopic ellipsometry analysis of a thin film composite membrane consisting of polysulfone on a porous α-alumina support.

PubMed

Ogieglo, Wojciech; Wormeester, Herbert; Wessling, Matthias; Benes, Nieck E

2012-02-01

Exposure of a thin polymer film to a fluid can affect properties of the film such as the density and thickness. In particular in membrane technology, these changes can have important implications for membrane performance. Spectroscopic ellipsometry is a convenient technique for in situ studies of thin films, because of its noninvasive character and very high precision. The applicability of spectroscopic ellipsometry is usually limited to samples with well-defined interfacial regions, whereas in typical composite membranes, often substantial and irregular intrusion of the thin film into the pores of a support exists. In this work, we provide a detailed characterization of a polished porous alumina membrane support, using variable-angle spectroscopic ellipsometry in combination with atomic force microscopy and mercury porosimetry. Two Spectroscopic ellipsometry optical models are presented that can adequately describe the surface roughness of the support. These models consider the surface roughness as a distinct layer in which the porosity gradually increases toward the outer ambient interface. The first model considers the porosity profile to be linear; the second model assumes an exponential profile. It is shown that the models can be extended to account for a composite membrane geometry, by deposition of a thin polysulfone film onto the support. The developed method facilitates practicability for in situ spectroscopic ellipsometry studies of nonequilibrium systems, i.e., membranes under actual permeation conditions.

Separation membrane development

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

Lee, M.W.

1998-08-01

A ceramic membrane has been developed to separate hydrogen from other gases. The method used is a sol-gel process. A thin layer of dense ceramic material is coated on a coarse ceramic filter substrate. The pore size distribution in the thin layer is controlled by a densification of the coating materials by heat treatment. The membrane has been tested by permeation measurement of the hydrogen and other gases. Selectivity of the membrane has been achieved to separate hydrogen from carbon monoxide. The permeation rate of hydrogen through the ceramic membrane was about 20 times larger than Pd-Ag membrane.

Incorporation of layered double nanomaterials in thin film nanocomposite nanofiltration membrane for magnesium sulphate removal

NASA Astrophysics Data System (ADS)

Hanis Tajuddin, Muhammad; Yusof, Norhaniza; Salleh, Wan Norharyati Wan; Fauzi Ismail, Ahmad; Hanis Hayati Hairom, Nur; Misdan, Nurasyikin

2018-03-01

Thin film nanocomposite (TFN) membrane with copper-aluminium layered double hydroxides (LDH) incorporated into polyamide (PA) selective layer has been prepared for magnesium sulphate salt removal. 0, 0.05, 0.1, 0.15, 0.2 wt% of LDH were dispersed in the trimesoyl chloride (TMC) in n-hexane as organic solution and embedded into PA layer during interfacial polymerization with piperazine. The fabricated membranes were further characterized to evaluate its morphological structure and membrane surface hydrophilicity. The TFN membranes performance were evaluated with divalent salt magnesium sulphate (MgSO4) removal and compared with thin film composite (TFC). The morphological structures of TFN membranes were altered and the surface hydrophilicity were enhanced with addition of LDH. Incorporation of LDH has improved the permeate water flux by 82.5% compared to that of TFC membrane with satisfactory rejection of MgSO4. This study has experimentally validated the potential of LDH to improve the divalent salt separation performance for TFN membranes.

A stable perovskite electrolyte in moist air for Li-ion batteries.

PubMed

Li, Yutao; Xu, Henghui; Chien, Po-Hsiu; Wu, Nan; Xin, Sen; Xue, Leigang; Park, Kyusung; Hu, Yan-Yan; Goodenough, John B

2018-05-07

Solid-oxide Li+ electrolytes of a rechargeable cell are generally sensitive to moisture in the air, H+ exchanges for the mobile Li+ of the electrolyte and forms insulating surface phases at the electrolyte interfaces and in the grain boundaries of a polycrystalline membrane. These surface phases dominate the total interfacial resistance of a conventional rechargeable cell having a solid-electrolyte separator. We report a new perovskite Li+ solid electrolyte, Li0.38Sr0.44Ta0.7Hf0.3O2.95F0.05, having a Li-ion conductivity σLi = 4.8×10-4 S cm-1 at 25 oC that does not react with water having 3≤pH≤14. The solid electrolyte with a thin Li+-conducting polymer on its surface to prevent reduction of Ta5+ is wet by metallic lithium and provides low-impedance dendrite-free plating/stripping of a lithium anode. It is also stable on contact with a composite polymer cathode. With this solid electrolyte, we demonstrate excellent cycling performance of an all-solid-state Li/LiFePO4 cell, a Li-S cell with a polymer-gel cathode, and a supercapacitor. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Applications of solid-state NMR to membrane proteins.

PubMed

Ladizhansky, Vladimir

2017-11-01

Membrane proteins mediate flow of molecules, signals, and energy between cells and intracellular compartments. Understanding membrane protein function requires a detailed understanding of the structural and dynamic properties involved. Lipid bilayers provide a native-like environment for structure-function investigations of membrane proteins. In this review we give a general discourse on the recent progress in the field of solid-state NMR of membrane proteins. Solid-state NMR is a variation of NMR spectroscopy that is applicable to molecular systems with restricted mobility, such as high molecular weight proteins and protein complexes, supramolecular assemblies, or membrane proteins in a phospholipid environment. We highlight recent advances in applications of solid-state NMR to membrane proteins, specifically focusing on the recent developments in the field of Dynamic Nuclear Polarization, proton detection, and solid-state NMR applications in situ (in cell membranes). This article is part of a Special Issue entitled: Biophysics in Canada, edited by Lewis Kay, John Baenziger, Albert Berghuis and Peter Tieleman. Copyright © 2017 Elsevier B.V. All rights reserved.

Interaction of Droplets Separated by an Elastic Film.

PubMed

Liu, Tianshu; Xu, Xuejuan; Nadermann, Nichole; He, Zhenping; Jagota, Anand; Hui, Chung-Yuen

2017-01-10

The Laplace pressure of a droplet placed on one side of an elastic thin film can cause significant deformation in the form of a bulge on its opposite side. Here, we show that this deformation can be detected by other droplets suspended on the opposite side of the film, leading to interaction between droplets separated by the solid (but deformable) film. The interaction is repulsive when the drops have a large overlap and attractive when they have a small overlap. Thus, if two identical droplets are placed right on top of each other (one on either side of the thin film), they tend to repel each other, eventually reaching an equilibrium configuration where there is a small overlap. This observation can be explained by analyzing the energy landscape of the droplets interacting via an elastically deformed film. We further demonstrate this idea by designing a pattern comprising a big central drop with satellite droplets. This phenomenon can lead to techniques for directed motion of droplets confined to one side of a thin elastic membrane by manipulations on the other side.

Gas Permeation in Thin Glassy Polymer Films

NASA Astrophysics Data System (ADS)

Paul, Donald

2011-03-01

The development of asymmetric and composite membranes with very thin dense ``skins'' needed to achieve high gas fluxes enabled the commercial use of membranes for molecular level separations. It has been generally assumed that these thin skins, with thicknesses of the order of 100 nm, have the same permeation characteristics as films with thicknesses of 25 microns or more. Thick films are easily made in the laboratory and have been used extensively for measuring permeation characteristics to evaluate the potential of new polymers for membrane applications. There is now evidence that this assumption can be in very significant error, and use of thick film data to select membrane materials or predict performance should be done with caution. This presentation will summarize our work on preparing films of glassy polymers as thin as 20 nm and characterizing their behavior by gas permeation, ellipsometry and positron annihilation lifetime spectroscopy. Some of the most important polymers used commercially as gas separation membranes, i.e., Matrimid polyimide, polysulfone (PSF) and poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), have been made into well-defined thin films in our laboratories by spin casting techniques and their properties studied using the techniques we have developed. These thin films densify (or physically age) much faster than thicker films, and, as result, the permeability decreases, sometimes by several-fold over weeks or months for thin films. This means that the properties of these thin films can be very different from bulk films. The techniques, interpretations and implications of these observations will be discussed. In a broader sense, gas permeation measurements can be a powerful way of developing a better understanding of the effects of polymer chain confinement and/or surface mobility on the behavior of thin films.

MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

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

T.M. Whitworth; Liangxiong Li

2002-09-15

This report describes work performed during the first year of the project ''Modified Reverse Osmosis System for Treatment of Produced Waters.'' This research project has two objectives. The first objective is to test the use of clay membranes in the treatment of produced waters by reverse osmosis. The second objective is to test the ability of a system patented by the New Mexico Tech Research Foundation to remove salts from reverse osmosis waste streams as a solid. We performed 12 experiments using clay membranes in cross-flow experimental cells. We found that, due to dispersion in the porous frit used adjacentmore » to the membrane, the concentration polarization layer seems to be completely (or nearly completely) destroyed at low flow rates. This observation suggests that clay membranes used with porous frit material many reach optimum rejection rates at lower pumping rates than required for use with synthetic membranes. The solute rejection efficiency decreases with increasing solution concentration. For the membranes and experiments reported here, the rejection efficiency ranged from 71% with 0.01 M NaCl solution down to 12% with 2.3 M NaCl solution. More compacted clay membranes will have higher rejection capabilities. The clay membranes used in our experiments were relatively thick (approximately 0.5 mm). The active layer of most synthetic membranes is only 0.04 {micro}m (0.00004 mm), approximately 1250 times thinner than the clay membranes used in these experiments. Yet clay membranes as thin as 12 {micro}m have been constructed (Fritz and Eady, 1985). Since Darcy's law states that the flow through a material of constant permeability is inversely proportional to it's the material's thickness, then, based on these experimental observations, a very thin clay membrane would be expected to have much higher flow rates than the ones used in these experiments. Future experiments will focus on testing very thin clay membranes. The membranes generally exhibited reasonable stable rejection rates over time for chloride for a range of concentrations between 0.01 and 2.5 M. One membrane ran in excess of three months with no apparent loss of usability. This suggests that clay membranes may have a long useable life. Twenty different hyperfiltration-induced solute precipitation experiments were either attempted or completed and are reported here. The results of these experiments suggest that hyperfiltration-induced solute precipitation is possible, even for very soluble substances such as NaCl. However, the precipitation rates obtained in the laboratory do not appear to be adequate for commercial application at this time. Future experiments will focus on making the clay membranes more compact and thinner in order to obtain higher flux rates. Two alternative methods of removing solutes from solution, for which the New Mexico Tech Research Foundation is preparing patent applications, are also being investigated. These methods will be described in the next annual report after the patent applications are filed. Technology transfer efforts included two meetings (one in Farmington NM, and one in Hobbs, NM) where the results of this research were presented to independent oil producers and other interested parties. In addition, members of the research team gave seven presentations concerning this research and because of this research project T. M. (Mike) Whitworth was asked to sit on the advisory board for development of a new water treatment facility for the City of El Paso, Texas. Several papers are in preparation for submission to peer-reviewed journals based on the data presented in this report.« less

Effectiveness of “Thin-Layer” and “Effective Medium” Approximations in Numerical Simulation of Dielectric Spectra of Biological Cell Suspensions

NASA Astrophysics Data System (ADS)

Asami, Koji

2010-12-01

There are a few concerns in dielectric modeling of biological cells by the finite-element method (FEM) to simulate their dielectric spectra. Cells possess thin plasma membranes and membrane-bound intracellular organelles, requiring extra fine meshes and considerable computational tasks in the simulation. To solve the problems, the “thin-layer” approximation (TLA) and the “effective medium” approximation (EMA) were adopted. TLA deals with the membrane as an interface of the specific membrane impedance, and therefore it is not necessary to divide the membrane region. EMA regards the composite cytoplasm as an effective homogeneous phase whose dielectric properties are calculated separately. It was proved that TLA and EMA were both useful for greatly reducing computational tasks while accurately coinciding with analytical solutions.

Solid-state membrane module

DOEpatents

Gordon, John Howard [Salt Lake City, UT; Taylor, Dale M [Murray, UT

2011-06-07

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

Fabrication of ultra thin anodic aluminium oxide membranes by low anodization voltages

NASA Astrophysics Data System (ADS)

Pastore, I.; Poplausks, R.; Apsite, I.; Pastare, I.; Lombardi, F.; Erts, D.

2011-06-01

Formation of ultrathin anodised aluminium oxide (AAO) membranes with high aspect ratio by Al anodization in sulphuric and oxalic acids at low potentials was investigated. Low anodization potentials ensure slow electrochemical reaction speeds and formation of AAO membranes with pore diameter and thickness below 20 nm and 70 nm respectively. Minimum time necessary for formation of continuous AAO membranes was determined. AAO membrane pore surface was covered with polymer Paraloid B72TM to transport it to the selected substrate. The fabricated ultra thin AAO membranes could be used to fabricate nanodot arrays on different surfaces.

Engineering aspects and hardware verification of a volume producable solid oxide fuel cell stack design for diesel auxiliary power units

NASA Astrophysics Data System (ADS)

Stelter, Michael; Reinert, Andreas; Mai, Björn Erik; Kuznecov, Mihail

A solid oxide fuel cell (SOFC) stack module is presented that is designed for operation on diesel reformate in an auxiliary power unit (APU). The stack was designed using a top-down approach, based on a specification of an APU system that is installed on board of vehicles. The stack design is planar, modular and scalable with stamped sheet metal interconnectors. It features thin membrane electrode assemblies (MEAs), such as electrolyte supported cells (ESC) and operates at elevated temperatures around 800 °C. The stack has a low pressure drop in both the anode and the cathode to facilitate a simple system layout. An overview of the technical targets met so far is given. A stack power density of 0.2 kW l -1 has been demonstrated in a fully integrated, thermally self-sustaining APU prototype running with diesel and without an external water supply.

An extreme ultraviolet Michelson interferometer for experiments at free-electron lasers

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

Hilbert, Vinzenz; Fuchs, Silvio; Paulus, Gerhard G.

2013-09-15

We present a Michelson interferometer for 13.5 nm soft x-ray radiation. It is characterized in a proof-of-principle experiment using synchrotron radiation, where the temporal coherence is measured to be 13 fs. The curvature of the thin-film beam splitter membrane is derived from the observed fringe pattern. The applicability of this Michelson interferometer at intense free-electron lasers is investigated, particularly with respect to radiation damage. This study highlights the potential role of such Michelson interferometers in solid density plasma investigations using, for instance, extreme soft x-ray free-electron lasers. A setup using the Michelson interferometer for pseudo-Nomarski-interferometry is proposed.

Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

PubMed Central

Reis, Rackel; Dumée, Ludovic F.; Tardy, Blaise L.; Dagastine, Raymond; Orbell, John D.; Schutz, Jürg A.; Duke, Mikel C.

2016-01-01

Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membranes has been significantly enhanced by rapid and facile, low pressure, argon plasma activation. Pressure driven water desalination tests showed that at low power density, flux was improved by 22% without compromising salt rejection. Various plasma durations and excitation powers have been systematically evaluated to assess the impact of plasma glow reactions on the physico-chemical properties of these materials associated with permeability. With increasing power density, plasma treatment enhanced the hydrophilicity of the surfaces, where water contact angles decreasing by 70% were strongly correlated with increased negative charge and smooth uniform surface morphology. These results highlight a versatile chemical modification technique for post-treatment of commercial membrane products that provides uniform morphology and chemically altered surface properties. PMID:27363670

Uniaxial and biaxial tensioning effects on thin membrane materials. [large space structures

NASA Technical Reports Server (NTRS)

Hinson, W. F.; Goslee, J. W.

1980-01-01

Thin laminated membranes are being considered for various surface applications on future large space structural systems. Some of the thin membranes would be stretched across or between structural members with the requirement that the membrane be maintained within specified limits of smoothness which would be dictated by the particular applications such as antenna reflector requirements. The multiaxial tensile force required to maintain the smoothness in the membrane needs to be determined for use in the structure design. Therefore, several types of thicknesses of thin membrane materials have been subjected to varied levels of uniaxial and biaxial tensile loads. During the biaxial tests, deviations of the material surface smoothness were measured by a noncontacting capacitance probe. Basic materials consisted of composites of vacuum deposited aluminum on Mylar and Kapton ranging in thickness from 0.00025 in (0.000635 cm) to 0.002 in (0.00508 cm). Some of the material was reinforced with Kevlar and Nomex scrim. The uniaxial tests determined the material elongation and tensile forces up to ultimate conditions. Biaxial tests indicated that a relatively smooth material surface could be achieved with tensile force of approximately 1 to 15 Newtons per centimeter, depending upon the material thickness and/or reinforcement.

A Solvent-Free Surface Suspension Melt Technique for Making Biodegradable PCL Membrane Scaffolds for Tissue Engineering Applications.

PubMed

Suntornnond, Ratima; An, Jia; Tijore, Ajay; Leong, Kah Fai; Chua, Chee Kai; Tan, Lay Poh

2016-03-21

In tissue engineering, there is limited availability of a simple, fast and solvent-free process for fabricating micro-porous thin membrane scaffolds. This paper presents the first report of a novel surface suspension melt technique to fabricate a micro-porous thin membrane scaffolds without using any organic solvent. Briefly, a layer of polycaprolactone (PCL) particles is directly spread on top of water in the form of a suspension. After that, with the use of heat, the powder layer is transformed into a melted layer, and following cooling, a thin membrane is obtained. Two different sizes of PCL powder particles (100 µm and 500 µm) are used. Results show that membranes made from 100 µm powders have lower thickness, smaller pore size, smoother surface, higher value of stiffness but lower ultimate tensile load compared to membranes made from 500 µm powder. C2C12 cell culture results indicate that the membrane supports cell growth and differentiation. Thus, this novel membrane generation method holds great promise for tissue engineering.

Detecting the Length of Double-stranded DNA with Solid State Nanopores

NASA Astrophysics Data System (ADS)

Li, Jiali; Gershow, Marc; Stein, Derek; Qun, Cai; Brandin, Eric; Wang, Hui; Huang, Albert; Branton, Dan; Golovchenko, Jene

2003-03-01

We report on the use of nanometer scale diameter, solid-state nanopores as single molecule detectors of double stranded DNA molecules. These solid-state nanopores are fabricated in thin membranes of silicon nitride, by ion beam sculpting 1. They produce discrete electronic signals: current blockages, when an electrically biased nanopore is exposed to DNA molecules in aqueous salt solutions. We demonstrate examples of such electronic signals for 3k base pairs (bp) and 10k bp double stranded DNA molecules, which suggest that these molecules are individually translocating through the nanopore during the detection process. The translocating time for the 10k bp double stranded DNA is about 3 times longer than the 3k bp, demonstrating that a solid-state nanopore device can be used to detect the lengths of double stranded DNA molecules. Similarities and differences with signals obtained from single stranded DNA in a biological nanopores are discussed 2. 1. Li, J., Stein, D., McMullan, C., Branton, D. Aziz, M. J. and Golovchenko, J. Ion Beam Sculpting at nanometer length scales. Nature 412, 166-169 (2001). 2. Meller, A., L. Nivon, E. Brandin, Golovchenko, J. & Branton, D. Proc. Natl. Acad. Sci. USA 97, 1079-1084 (2000).

A three-dimensional architecture of vertically aligned multilayer graphene facilitates heat dissipation across joint solid surfaces

NASA Astrophysics Data System (ADS)

Liang, Qizhen; Yao, Xuxia; Wang, Wei; Wong, C. P.

2012-02-01

Low operation temperature and efficient heat dissipation are important for device life and speed in current electronic and photonic technologies. Being ultra-high thermally conductive, graphene is a promising material candidate for heat dissipation improvement in devices. In the application, graphene is expected to be vertically stacked between contact solid surfaces in order to facilitate efficient heat dissipation and reduced interfacial thermal resistance across contact solid surfaces. However, as an ultra-thin membrane-like material, graphene is susceptible to Van der Waals forces and usually tends to be recumbent on substrates. Thereby, direct growth of vertically aligned free-standing graphene on solid substrates in large scale is difficult and rarely available in current studies, bringing significant barriers in graphene's application as thermal conductive media between joint solid surfaces. In this work, a three-dimensional vertically aligned multi-layer graphene architecture is constructed between contacted Silicon/Silicon surfaces with pure Indium as a metallic medium. Significantly higher equivalent thermal conductivity and lower contact thermal resistance of vertically aligned multilayer graphene are obtained, compared with those of their recumbent counterpart. This finding provides knowledge of vertically aligned graphene architectures, which may not only facilitate current demanding thermal management but also promote graphene's widespread applications such as electrodes for energy storage devices, polymeric anisotropic conductive adhesives, etc.

Reduction of methanol crossover by thin cracked metal barriers at the interface between membrane and electrode in direct methanol fuel cells

NASA Astrophysics Data System (ADS)

Kim, Sungjun; Jang, Segeun; Kim, Sang Moon; Ahn, Chi-Yeong; Hwang, Wonchan; Cho, Yong-Hun; Sung, Yung-Eun; Choi, Mansoo

2017-09-01

This work reports the successful reduction in methanol crossover by creating a thin cracked metal barrier at the interface between a Nafion® membrane and an electrode in direct methanol fuel cells (DMFCs). The cracks are generated by simple mechanical stretching of a metal deposited Nafion® membrane as a result of the elastic mismatch between the two attached surfaces. The cracked metal barriers with varying strains (∼0.5 and ∼1.0) are investigated and successfully incorporated into the DMFC. Remarkably, the membrane electrode assembly with the thin metal crack exhibits comparable ohmic resistance as well as reduction of methanol crossover, which enhanced the device performance.

Gradient composite metal-ceramic foam as supportive component for planar SOFCs and MIEC membranes

NASA Astrophysics Data System (ADS)

Smorygo, Oleg; Mikutski, Vitali; Marukovich, Alexander; Sadykov, Vladislav; Usoltsev, Vladimir; Mezentseva, Natalia; Borodinecs, Anatolijs; Bobrenok, Oleg

2011-06-01

A novel approach to the design of planar gradient porous supports for the thin-film SOFCs and MIEC membranes is described. The support's thermal expansion is controlled by the creation of a two-component composite metal-ceramic foam structure. Thin MIEC membranes and SOFCs were prepared on the composite supports by the layerwise deposition of composite functional layers including complex fluorites and perovskites. Lab-scale studies demonstrated promising performance of both MIEC membrane and SOFC.

Method of synthesizing polymers from a solid electrolyte

DOEpatents

Skotheim, Terje A.

1985-01-01

A method of synthesizing electrically conductive polymers from a solvent-free solid polymer electrolyte wherein an assembly of a substrate having an electrode thereon, a thin coating of solid electrolyte including a solution of PEO complexed with an alkali salt, and a thin transparent noble metal electrode are disposed in an evacuated chamber into which a selected monomer vapor is introduced while an electric potential is applied across the solid electrolyte to hold the thin transparent electrode at a positive potential relative to the electrode on the substrate, whereby a highly conductive polymer film is grown on the transparent electrode between it and the solid electrolyte.

Method of synthesizing polymers from a solid electrolyte

DOEpatents

Skotheim, T.A.

1984-10-19

A method of synthesizing electrically conductive polymers from a solvent-free solid polymer electrolyte is disclosed. An assembly of a substrate having an electrode thereon, a thin coating of solid electrolyte including a solution of PEO complexed with an alkali salt, and a thin transparent noble metal electrode are disposed in an evacuated chamber into which a selected monomer vapor is introduced while an electric potential is applied across the solid electrolyte to hold the thin transparent electrode at a positive potential relative to the electrode on the substrate, whereby a highly conductive polymer film is grown on the transparent electrode between it and the solid electrolyte.

Fabrication of ultrathin solid electrolyte membranes of β-Li 3PS 4 nanoflakes by evaporation-induced self-assembly for all-solid-state batteries

DOE PAGES

Wang, Hui; Hood, Zachary D.; Xia, Younan; ...

2016-04-25

All-solid-state lithium batteries are attractive candidates for next-generation energy storage devices because of their anticipated high energy density and intrinsic safety. Owing to their excellent ionic conductivity and stability with metallic lithium anodes, nanostructured lithium thiophosphate solid electrolytes such as β-Li 3PS 4 have found use in the fabrication of all-solid lithium batteries for large-scale energy storage systems. However, current methods for preparing air-sensitive solid electrolyte membranes of lithium thiophosphates can only generate thick membranes that compromise the battery's gravimetric/volumetric energy density and thus its rate performance. To overcome this limitation, the solid electrolyte's thickness needs to be effectively decreasedmore » to achieve ideal energy density and enhanced rate performance. In this paper, we show that the evaporation-induced self-assembly (EISA) technique produces ultrathin membranes of a lithium thiophosphate solid electrolyte with controllable thicknesses between 8 and 50 μm while maintaining the high ionic conductivity of β-Li 3PS 4 and stability with metallic lithium anodes up to 5 V. Finally, it is clearly demonstrated that this facile EISA approach allows for the preparation of ultrathin lithium thiophosphate solid electrolyte membranes for all-solid-state batteries.« less

Semipermeable thin-film membranes comprising siloxane, alkoxysilyl and aryloxysilyl oligomers and copolymers

DOEpatents

Babcock, W.C.; Friesen, D.T.

1988-11-01

Novel semipermeable membranes and thin film composite (TFC) gas separation membranes useful in the separation of oxygen, nitrogen, hydrogen, water vapor, methane, carbon dioxide, hydrogen sulfide, lower hydrocarbons, and other gases are disclosed. The novel semipermeable membranes comprise the polycondensation reaction product of two complementary polyfunctional compounds, each having at least two functional groups that are mutually reactive in a condensation polymerization reaction, and at least one of which is selected from siloxanes, alkoxsilyls and aryloxysilyls. The TFC membrane comprises a microporous polymeric support, the surface of which has the novel semipermeable film formed thereon, preferably by interfacial polymerization.

Semipermeable thin-film membranes comprising siloxane, alkoxysilyl and aryloxysilyl oligomers and copolymers

DOEpatents

Babcock, Walter C.; Friesen, Dwayne T.

1988-01-01

Novel semiperimeable membranes and thin film composite (TFC) gas separation membranes useful in the separation of oxygen, nitrogen, hydrogen, water vapor, methane, carbon dioxide, hydrogen sulfide, lower hydrocarbons, and other gases are disclosed. The novel semipermeable membranes comprise the polycondensation reaction product of two complementary polyfunctional compounds, each having at least two functional groups that are mutually reactive in a condensation polymerization reaction, and at least one of which is selected from siloxanes, alkoxsilyls and aryloxysilyls. The TFC membrane comprises a microporous polymeric support, the surface of which has the novel semipermeable film formed thereon, preferably by interfacial polymerization.

Preparation and characterization of titania-deposited silica composite hollow fiber membranes with high hydrothermal stability.

PubMed

Kwon, Young-Nam; Kim, In-Chul

2013-11-01

Hydrothermal stability of a porous nickel-supported silica membrane was successfully improved by deposition of titania multilayers on colloidal silica particles embedded in the porous nickel fiber support. Porous nickel-supported silica membranes were prepared by means of a dipping-freezing-fast drying (DFF) method. The titania layers were deposited on colloidal silica particles by repeating hydrolysis and condensation reactions of titanium isopropoxide on the silica particle surfaces. The deposition of thin titania layers on the nickel-supported silica membrane was verified by various analytical tools. The water flux and the solute rejection of the porous Ni fiber-supported silica membranes did not change after titania layer deposition, indicating that thickness of titania layers deposited on silica surface is enough thin not to affect the membrane performance. Moreover, improvement of the hydrothermal stability in the titania-deposited silica membranes was confirmed by stability tests, indicating that thin titania layers deposited on silica surface played an important role as a diffusion barrier against 90 degrees C water into silica particles.

Solid polymer electrolyte composite membrane comprising laser micromachined porous support

DOEpatents

Liu, Han [Waltham, MA; LaConti, Anthony B [Lynnfield, MA; Mittelsteadt, Cortney K [Natick, MA; McCallum, Thomas J [Ashland, MA

2011-01-11

A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a rigid, non-electrically-conducting support, the support preferably being a sheet of polyimide having a thickness of about 7.5 to 15 microns. The support has a plurality of cylindrical pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores, which preferably have a diameter of about 5 microns, are made by laser micromachining and preferably are arranged in a defined pattern, for example, with fewer pores located in areas of high membrane stress and more pores located in areas of low membrane stress. The pores are filled with a first solid polymer electrolyte, such as a perfluorosulfonic acid (PFSA) polymer. A second solid polymer electrolyte, which may be the same as or different than the first solid polymer electrolyte, may be deposited over the top and/or bottom of the first solid polymer electrolyte.

Solid polymer electrolyte composite membrane comprising plasma etched porous support

DOEpatents

Liu, Han; LaConti, Anthony B.

2010-10-05

A solid polymer electrolyte composite membrane and method of manufacturing the same. According to one embodiment, the composite membrane comprises a rigid, non-electrically-conducting support, the support preferably being a sheet of polyimide having a thickness of about 7.5 to 15 microns. The support has a plurality of cylindrical pores extending perpendicularly between opposing top and bottom surfaces of the support. The pores, which preferably have a diameter of about 0.1 to 5 microns, are made by plasma etching and preferably are arranged in a defined pattern, for example, with fewer pores located in areas of high membrane stress and more pores located in areas of low membrane stress. The pores are filled with a first solid polymer electrolyte, such as a perfluorosulfonic acid (PFSA) polymer. A second solid polymer electrolyte, which may be the same as or different than the first solid polymer electrolyte, may be deposited over the top and/or bottom of the first solid polymer electrolyte.

Proton exchange membranes prepared by grafting of styrene/divinylbenzene into crosslinked PTFE membranes

NASA Astrophysics Data System (ADS)

Li, Jingye; Ichizuri, Shogo; Asano, Saneto; Mutou, Fumihiro; Ikeda, Shigetoshi; Iida, Minoru; Miura, Takaharu; Oshima, Akihiro; Tabata, Yoneho; Washio, Masakazu

2005-07-01

Thin PTFE membranes were prepared by coating the PTFE dispersion onto the aluminum films. Thus the thin crosslinked PTFE (RX-PTFE) membranes were obtained by means of electron beam irradiation above the melting temperature of PTFE under oxygen-free atmosphere. The RX-PTFE membranes were pre-irradiated and grafted by styrene with or without divinylbenzene (DVB) in liquid phase. The existence of DVB accelerated the initial grafting rate. The styrene grafted RX-PTFE membranes are white colored, on the other hand, the styrene/DVB grafted RX-PTFE membranes are colorless. The proton exchange membranes (PEMs) were obtained by sulfonating the grafted membranes using chlorosulfonic acid. The ion exchange capacity (IEC) values of the PEMs ranging from 1.5 to 2.8 meq/g were obtained. The PEMs made from the styrene/DVB grafted membranes showed higher chemical stability than those of the styrene grafted membranes under oxidative circumstance.

Biomimetic Dissolution: A Tool to Predict Amorphous Solid Dispersion Performance.

PubMed

Puppolo, Michael M; Hughey, Justin R; Dillon, Traciann; Storey, David; Jansen-Varnum, Susan

2017-11-01

The presented study describes the development of a membrane permeation non-sink dissolution method that can provide analysis of complete drug speciation and emulate the in vivo performance of poorly water-soluble Biopharmaceutical Classification System class II compounds. The designed membrane permeation methodology permits evaluation of free/dissolved/unbound drug from amorphous solid dispersion formulations with the use of a two-cell apparatus, biorelevant dissolution media, and a biomimetic polymer membrane. It offers insight into oral drug dissolution, permeation, and absorption. Amorphous solid dispersions of felodipine were prepared by hot melt extrusion and spray drying techniques and evaluated for in vitro performance. Prior to ranking performance of extruded and spray-dried felodipine solid dispersions, optimization of the dissolution methodology was performed for parameters such as agitation rate, membrane type, and membrane pore size. The particle size and zeta potential were analyzed during dissolution experiments to understand drug/polymer speciation and supersaturation sustainment of felodipine solid dispersions. Bland-Altman analysis was performed to measure the agreement or equivalence between dissolution profiles acquired using polymer membranes and porcine intestines and to establish the biomimetic nature of the treated polymer membranes. The utility of the membrane permeation dissolution methodology is seen during the evaluation of felodipine solid dispersions produced by spray drying and hot melt extrusion. The membrane permeation dissolution methodology can suggest formulation performance and be employed as a screening tool for selection of candidates to move forward to pharmacokinetic studies. Furthermore, the presented model is a cost-effective technique.

Hyper-Cross-Linked Additives that Impede Aging and Enhance Permeability in Thin Polyacetylene Films for Organic Solvent Nanofiltration.

PubMed

Cheng, Xi Quan; Konstas, Kristina; Doherty, Cara M; Wood, Colin D; Mulet, Xavier; Xie, Zongli; Ng, Derrick; Hill, Matthew R; Shao, Lu; Lau, Cher Hon

2017-04-26

Membrane materials with high permeability to solvents while rejecting dissolved contaminants are crucial to lowering the energy costs associated with liquid separations. However, the current lack of stable high-permeability materials require innovative engineering solutions to yield high-performance, thin membranes using stable polymers with low permeabilities. Poly[1-(trimethylsilyl)-1-propyne] (PTMSP) is one of the most permeable polymers but is extremely susceptible to physical aging. Despite recent developments in anti-aging polymer membranes, this research breakthrough has yet to be demonstrated on thin PTMSP films supported on porous polymer substrates, a crucial step toward commercializing anti-aging membranes for industrial applications. Here we report the development of scalable, thin film nanocomposite membranes supported on polymer substrates that are resistant to physical aging while having high permeabilities to alcohols. The selective layer is made up of PTMSP and nanoporous polymeric additives. The nanoporous additives provide additional passageways to solvents, enhancing the high permeability of the PTMSP materials further. Through intercalation of polyacetylene chains into the sub-nm pores of organic additives, physical aging in the consequent was significantly hindered in continuous long-term operation. Remarkably we also demonstrate that the additives enhance both membrane permeability and rejection of dissolved contaminants across the membranes, as ethanol permeability at 5.5 × 10 -6 L m m -2 h -1 bar -1 with 93% Rose Bengal (1017.6 g mol -1 ) rejection, drastically outperforming commercial and state-of-the-art membranes. These membranes can replace energy-intensive separation processes such as distillation, lowering operation costs in well-established pharmaceutical production processes.

Interaction of Salicylate and a Terpenoid Plant Extract with Model Membranes: Reconciling Experiments and Simulations

PubMed Central

Khandelia, Himanshu; Witzke, Sarah; Mouritsen, Ole G.

2010-01-01

We investigate the effects of two structurally similar small cyclic molecules: salicylic acid and perillic acid on a zwitterionic model lipid bilayer, and show that both molecules might have biological activity related to membrane thinning. Salicylic acid is a nonsteroidal antiinflammatory drug, some of the pharmacological properties of which arise from its interaction with the lipid bilayer component of the plasma membrane. Prior simulations show that salicylate orders zwitterionic lipid membranes. However, this is in conflict with Raman scattering and vesicle fluctuation analysis data, which suggest the opposite. We show using extensive molecular dynamics simulations, cumulatively >2.5 μs, that salicylic acid indeed disorders membranes with concomitant membrane thinning and that the conflict arose because prior simulations suffered from artifacts related to the sodium-ion induced condensation of zwitterionic lipids modeled by the Berger force field. Perillic acid is a terpenoid plant extract that has antiinfective and anticancer properties, and is extensively used in eastern medicine. We found that perillic acid causes large-scale membrane thinning and could therefore exert its antimicrobial properties via a membrane-lytic mechanism reminiscent of antimicrobial peptides. Being more amphipathic, perillic acid is more potent in disrupting lipid headgroup packing, and significantly modifies headgroup dipole orientation. Like salicylate, the membrane thinning effect of perillic acid is masked by the presence of sodium ions. As an alternative to sodium cations, we advocate the straightforward solution of using larger countercations like potassium or tetra-methyl-ammonium that will maintain electroneutrality but not interact strongly with, and thus not condense, the lipid bilayer. PMID:21156130

Ultrafast nonlinear optical properties of thin-solid DNA film and their application as a saturable absorber in femtosecond mode-locked fiber laser

PubMed Central

Khazaeinezhad, Reza; Hosseinzadeh Kassani, Sahar; Paulson, Bjorn; Jeong, Hwanseong; Gwak, Jiyoon; Rotermund, Fabian; Yeom, Dong-Il; Oh, Kyunghwan

2017-01-01

A new extraordinary application of deoxyribonucleic acid (DNA) thin-solid-film was experimentally explored in the field of ultrafast nonlinear photonics. Optical transmission was investigated in both linear and nonlinear regimes for two types of DNA thin-solid-films made from DNA in aqueous solution and DNA-cetyltrimethylammonium chloride (CTMA) in an organic solvent. Z-scan measurements revealed a high third-order nonlinearity with n2 exceeding 10−9 at a wavelength of 1570 nm, for a nonlinarity about five orders of magnitude larger than that of silica. We also demonstrated ultrafast saturable absorption (SA) with a modulation depth of 0.43%. DNA thin solid films were successfully deposited on a side-polished optical fiber, providing an efficient evanescent wave interaction. We built an organic-inorganic hybrid all-fiber ring laser using DNA film as an ultrafast SA and using Erbium-doped fiber as an efficient optical gain medium. Stable transform-limited femtosecond soliton pulses were generated with full width half maxima of 417 fs for DNA and 323 fs for DNA-CTMA thin-solid-film SAs. The average output power was 4.20 mW for DNA and 5.46 mW for DNA-CTMA. Detailed conditions for DNA solid film preparation, dispersion control in the laser cavity and subsequent characteristics of soliton pulses are discussed, to confirm unique nonlinear optical applications of DNA thin-solid-film. PMID:28128340

Structure and Assembly of Intracellular Mature Vaccinia Virus: Thin-Section Analyses

PubMed Central

Griffiths, Gareth; Roos, Norbert; Schleich, Sybille; Locker, Jacomine Krijnse

2001-01-01

In the preceding study (see accompanying paper), we showed by a variety of different techniques that intracellular mature vaccinia virus (vaccinia IMV) is unexpectedly complex in its structural organization and that this complexity also extends to the underlying viral core, which is highly folded. With that analysis as a foundation, we now present different thin-section electron microscopy approaches for analyzing the IMV and the processes by which it is assembled in infected HeLa cells. We focus on conventional epoxy resin thin sections as well as cryosections to describe key intermediates in the assembly process. We took advantage of streptolysin O's ability to selectively permeabilize the plasma membrane of infected cells to improve membrane contrast, and we used antibodies against bone fide integral membrane proteins of the virus to unequivocally identify membrane profiles in thin sections. All of the images presented here can be rationalized with respect to the model put forward for the assembly of the IMV in the accompanying paper. PMID:11602745

Functional anatomy of gliding membrane muscles in the sugar glider (Petaurus breviceps).

PubMed

Endo, H; Yokokawa, K; Kurohmaru, M; Hayashi, Y

1998-02-01

In order to clarify the morphological adaptation for gliding behavior in the marsupial mammals, the gliding membrane muscles in the sugar glider (Petaurus breviceps) were observed. Unlike the styliform cartilage in flying squirrels, the sugar glider has a well-developed tibiocarpalis muscle in the most lateral area of the gliding membrane. The gliding membrane substantially consists of the humerodorsalis and tibioabdominalis muscle complex. We believe that the thick tibiocarpalis bundle and the humerodorsalis and tibioabdominalis muscle complex may serve as a membrane controller in the gliding behavior. A characteristic thin membranous structure between the cutaneous and deeper muscles was observed. In addition to the direct powerful control exerted by trunk and limb movement, we suggest that indirect power conduction by this thin membranous structure may contribute to gliding membrane control.

Drop dynamics on a thin film: Thin film rupture

NASA Astrophysics Data System (ADS)

Carlson, Andreas; Kim, Pilnam; Stone, Howard A.

2011-11-01

The spreading of a water drop on an oil film that covers a solid substrate is a common event in many industrial processes. We study in experiments the dynamics of a water drop on a thin silicone oil film and quantify its interaction with the solid substrate that supports the film. The oil film becomes unstable and ruptures for solids that are hydrophilic. We determine the ``waiting time,'' the time it takes the water drop to drain the silicone film. This timescale is found to highly depend on how well water wets the solid, illustrating the interplay between intermolecular and hydrodynamic forces in the phenomenon. A phase diagram for the thin film stability is extracted based on waters equilibrium contact angle on the solid, which shows that we can either promote or inhibit de-wetting. As water comes in direct contact with the solid, it spreads and peels off the silicone film. We show the influence of viscosity, equilibrium contact angle and film height on the opening radius of the hole formed as the solid de-wets.

Nonlinear Shell Modeling of Thin Membranes with Emphasis on Structural Wrinkling

NASA Technical Reports Server (NTRS)

Tessler, Alexander; Sleight, David W.; Wang, John T.

2003-01-01

Thin solar sail membranes of very large span are being envisioned for near-term space missions. One major design issue that is inherent to these very flexible structures is the formation of wrinkling patterns. Structural wrinkles may deteriorate a solar sail's performance and, in certain cases, structural integrity. In this paper, a geometrically nonlinear, updated Lagrangian shell formulation is employed using the ABAQUS finite element code to simulate the formation of wrinkled deformations in thin-film membranes. The restrictive assumptions of true membranes, i.e. Tension Field theory (TF), are not invoked. Two effective modeling strategies are introduced to facilitate convergent solutions of wrinkled equilibrium states. Several numerical studies are carried out, and the results are compared with recent experimental data. Good agreement is observed between the numerical simulations and experimental data.

Surface modification of thin film composite reverse osmosis membrane by glycerol assisted oxidation with sodium hypochlorite

NASA Astrophysics Data System (ADS)

Raval, Hiren D.; Samnani, Mohit D.; Gauswami, Maulik V.

2018-01-01

Need for improvement in water flux of thin film composite (TFC) RO membrane has been appreciated by researchers world over and surface modification approach is found promising to achieve higher water flux and solute rejection. Thin film composite RO membrane was exposed to 2000 mg/l sodium hypochlorite solution with varying concentrations of glycerol ranging from 1 to 10%. It was found that there was a drop in concentration of sodium hypochlorite after the addition of glycerol because of a new compound resulted from the oxidation of glycerol with sodium hypochlorite. The water flux of the membrane treated with 1% glycerol with 2000 mg/l sodium hypochlorite for 1 h was about 22% more and salt rejection was 1.36% greater than that of only sodium hypochlorite treated membrane for the same concentration and time. There was an increase in salt rejection of membrane with increase in concentration of glycerol from 1% to 5%, however, increasing glycerol concentration further up to 10%, the salt rejection declined. The water flux was found declining from 1% glycerol solution to 10% glycerol solution. The membrane samples were characterized to understand the change in chemical structure and morphology of the membrane.

Protein nanocoatings on synthetic polymeric nanofibrous membranes designed as carriers for skin cells.

PubMed

Bacakova, Marketa; Pajorova, Julia; Stranska, Denisa; Hadraba, Daniel; Lopot, Frantisek; Riedel, Tomas; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

2017-01-01

Protein-coated resorbable synthetic polymeric nanofibrous membranes are promising for the fabrication of advanced skin substitutes. We fabricated electrospun polylactic acid and poly(lactide- co -glycolic acid) nanofibrous membranes and coated them with fibrin or collagen I. Fibronectin was attached to a fibrin or collagen nanocoating, in order further to enhance the cell adhesion and spreading. Fibrin regularly formed a coating around individual nanofibers in the membranes, and also formed a thin noncontinuous nanofibrous mesh on top of the membranes. Collagen also coated most of the fibers of the membrane and randomly created a soft gel on the membrane surface. Fibronectin predominantly adsorbed onto a thin fibrin mesh or a collagen gel, and formed a thin nanofibrous structure. Fibrin nanocoating greatly improved the attachment, spreading, and proliferation of human dermal fibroblasts, whereas collagen nanocoating had a positive influence on the behavior of human HaCaT keratinocytes. In addition, fibrin stimulated the fibroblasts to synthesize fibronectin and to deposit it as an extracellular matrix. Fibrin coating also showed a tendency to improve the ultimate tensile strength of the nanofibrous membranes. Fibronectin attached to fibrin or to a collagen coating further enhanced the adhesion, spreading, and proliferation of both cell types.

Protein nanocoatings on synthetic polymeric nanofibrous membranes designed as carriers for skin cells

PubMed Central

Bacakova, Marketa; Pajorova, Julia; Stranska, Denisa; Hadraba, Daniel; Lopot, Frantisek; Riedel, Tomas; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

2017-01-01

Protein-coated resorbable synthetic polymeric nanofibrous membranes are promising for the fabrication of advanced skin substitutes. We fabricated electrospun polylactic acid and poly(lactide-co-glycolic acid) nanofibrous membranes and coated them with fibrin or collagen I. Fibronectin was attached to a fibrin or collagen nanocoating, in order further to enhance the cell adhesion and spreading. Fibrin regularly formed a coating around individual nanofibers in the membranes, and also formed a thin noncontinuous nanofibrous mesh on top of the membranes. Collagen also coated most of the fibers of the membrane and randomly created a soft gel on the membrane surface. Fibronectin predominantly adsorbed onto a thin fibrin mesh or a collagen gel, and formed a thin nanofibrous structure. Fibrin nanocoating greatly improved the attachment, spreading, and proliferation of human dermal fibroblasts, whereas collagen nanocoating had a positive influence on the behavior of human HaCaT keratinocytes. In addition, fibrin stimulated the fibroblasts to synthesize fibronectin and to deposit it as an extracellular matrix. Fibrin coating also showed a tendency to improve the ultimate tensile strength of the nanofibrous membranes. Fibronectin attached to fibrin or to a collagen coating further enhanced the adhesion, spreading, and proliferation of both cell types. PMID:28223803

Chemical compositions, methods of making the chemical compositions, and structures made from the chemical compositions

DOEpatents

Yang, Lei; Cheng, Zhe; Liu, Ze; Liu, Meilin

2015-01-13

Embodiments of the present disclosure include chemical compositions, structures, anodes, cathodes, electrolytes for solid oxide fuel cells, solid oxide fuel cells, fuel cells, fuel cell membranes, separation membranes, catalytic membranes, sensors, coatings for electrolytes, electrodes, membranes, and catalysts, and the like, are disclosed.

Grafted functional groups on expanded tetrafluoroethylene (ePTFE) support for fuel cell and water transport membranes

DOEpatents

Fuller, Timothy J.; Jiang, Ruichun

2017-01-24

A method for forming a modified solid polymer includes a step of contacting a solid fluorinated polymer with a sodium sodium-naphthalenide solution to form a treated fluorinated solid polymer. The treated fluorinated solid polymer is contacted with carbon dioxide, sulfur dioxide, or sulfur trioxide to form a solid grafted fluorinated polymer. Characteristically, the grafted fluorinated polymer includes appended CO.sub.2H or SO.sub.2H or SO.sub.3H groups. The solid grafted fluorinated polymer is advantageously incorporated into a fuel cell as part of the ion-conducting membrane or a water transport membrane in a humidifier.

Feed gas contaminant removal in ion transport membrane systems

DOEpatents

Underwood, Richard Paul [Allentown, PA; Makitka, III, Alexander; Carolan, Michael Francis [Allentown, PA

2012-04-03

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.

Micromachined sensor for stress measurement and micromechanical study of free-standing thin films for MEMS applications

NASA Astrophysics Data System (ADS)

Zhang, Ping

Microelectromechanical systems (MEMS) have a wide range of applications. In the field of wireless and microwave technology, considerable attention has been given to the development and integration of MEMS-based RF (radio frequency) components. An RF MEMS switch requires low insertion loss, high isolation, and low actuation voltage - electrical aspects that have been extensively studied. The mechanical requirements of the switch, such as low sensitivity to built-in stress and high reliability, greatly depend on the micromechanical properties of the switch materials, and have not been thoroughly explored. RF MEMS switches are typically in the form of a free-standing thin film structure. Large stress gradients and across-wafer stress variations developed during fabrication severely degrade their electrical performance. A micromachined stress measurement sensor has been developed that can potentially be employed for in-situ monitoring of stress evolution and stress variation. The sensors were micromachined using five masks on two wafer levels, each measuring 5x3x1 mm. They function by means of an electron tunneling mechanism, where a 2x2 mm silicon nitride membrane elastically deflects under an applied deflection voltage via an external feedback circuitry. For the current design, the sensors are capable of measuring tensile stresses up to the GPa range under deflection voltages of 50--100 V. Sensor functionality was studied by finite element modeling and a theoretical analysis of square membrane deflection. While the mechanical properties of thin films on substrates have been extensively studied, studies of free-standing thin films have been limited due to the practical difficulties in sample handling and testing. Free-standing Al and Al-Ti thin films specimens have been successfully fabricated and microtensile and stress relaxation tests have been performed using a custom-designed micromechanical testing apparatus. A dedicated TEM (transmission electron microscopy) sample preparation technique allows the investigation of the microstructures of these thin films both before and after mechanical testing to correlate the microstructural findings with the mechanical behavior. Major studies include grain boundary strengthening in pure Al, plastic deformation in pure Al by inhomogeneous deformation and localized grain thinning, solid solution and precipitate strengthening in Al-Ti alloys, and stress relaxation of Al and Al-Ti.

Explicit formulation of an anisotropic Allman/DKT 3-node thin triangular flat shell elements

NASA Astrophysics Data System (ADS)

Ertas, A.; Krafcik, J. T.; Ekwaro-Osire, S.

A simple, explicit formulation of the stiffness matrix for an anisotropic, 3-node, thin triangular, flat shell element in global coordinates is presented. An Allman triangle is used for membrane stiffness. The membrane stiffness matrix is explicitly derived by applying an Allman transformation to a Felippa 6-node linear strain triangle (LST). Bending stiffness is incorporated by the use of a discrete Kirchhoff triangle (DKT) bending triangle. Stiffness terms resulting from anisotropic membrane-bending coupling are included by integrating, in area coordinates, membrane and bending strain-displacement matrices.

Apparatus and method for transient thermal infrared emission spectrometry

DOEpatents

McClelland, John F.; Jones, Roger W.

1991-12-24

A method and apparatus for enabling analysis of a solid material (16, 42) by applying energy from an energy source (20, 70) top a surface region of the solid material sufficient to cause transient heating in a thin surface layer portion of the solid material (16, 42) so as to enable transient thermal emission of infrared radiation from the thin surface layer portion, and by detecting with a spectrometer/detector (28, 58) substantially only the transient thermal emission of infrared radiation from the thin surface layer portion of the solid material. The detected transient thermal emission of infrared radiation is sufficiently free of self-absorption by the solid material of emitted infrared radiation, so as to be indicative of characteristics relating to molecular composition of the solid material.

Surface modification of thin film composite membrane by nanoporous titanate nanoparticles for improving combined organic and inorganic antifouling properties.

PubMed

Emadzadeh, D; Ghanbari, M; Lau, W J; Rahbari-Sisakht, M; Rana, D; Matsuura, T; Kruczek, B; Ismail, A F

2017-06-01

In this study, nanoporous titanate (NT) nanoparticle synthesized by the solvothermal method was used to modify polyamide layer of thin film composite membranes with the aim of improving membrane resistances against organic and inorganic fouling. Thin film nanocomposite membranes (NMs) were synthesized by adding mNTs (modified nanoparticles) into polyamide selective layer followed by characterization using different analytical instruments. The results of XPS and XRD confirmed the presence of mNTs in the polyamide layer of NMs, while FESEM, AFM, zeta potential and contact angle measurement further supported the changes in physical and chemical properties of the membrane surface upon mNTs incorporation. Results of fouling showed that NM1 (the membrane incorporated with 0.01w/v% mNTs) always demonstrated lower degree of flux decline compared to the control membrane when membranes were tested with organic, inorganic and multicomponent synthesized water, brackish water or seawater. Besides showing greater antifouling resistance, the NM also displayed significantly higher water flux compared to the control M membrane. The findings of this work confirmed the positive impact of mNTs in improving the properties of NM with respect to fouling mitigation and flux improvement. Copyright © 2017. Published by Elsevier B.V.

In-situ formation of solidified hydrogen thin-membrane targets using a pulse tube cryocooler

NASA Astrophysics Data System (ADS)

Astbury, S.; Bedacht, S.; Brummitt, P.; Carroll, D.; Clarke, R.; Crisp, S.; Hernandez-Gomez, C.; Holligan, P.; Hook, S.; Merchan, J. S.; Neely, D.; Ortner, A.; Rathbone, D.; Rice, P.; Schaumann, G.; Scott, G.; Spindloe, C.; Spurdle, S.; Tebartz, A.; Tomlinson, S.; Wagner, F.; Borghesi, M.; Roth, M.; Tolley, M. K.

2016-04-01

An account is given of the Central Laser Facility's work to produce a cryogenic hydrogen targetry system using a pulse tube cryocooler. Due to the increasing demand for low Z thin laser targets, CLF (in collaboration with TUD) have been developing a system which allows the production of solid hydrogen membranes by engineering a design which can achieve this remotely; enabling the gas injection, condensation and solidification of hydrogen without compromising the vacuum of the target chamber. A dynamic sealing mechanism was integrated which allows targets to be grown and then remotely exposed to open vacuum for laser interaction. Further research was conducted on the survivability of the cryogenic targets which concluded that a warm gas effect causes temperature spiking when exposing the solidified hydrogen to the outer vacuum. This effect was shown to be mitigated by improving the pumping capacity of the environment and reducing the minimum temperature obtainable on the target mount. This was achieved by developing a two-stage radiation shield encased with superinsulating blanketing; reducing the base temperature from 14 ± 0.5 K to 7.2 ± 0.2 K about the coldhead as well as improving temperature control stability following the installation of a high-performance temperature controller and sensor apparatus. The system was delivered experimentally and in July 2014 the first laser shots were taken upon hydrogen targets in the Vulcan TAP facility.

Theory of linear sweep voltammetry with diffuse charge: Unsupported electrolytes, thin films, and leaky membranes

NASA Astrophysics Data System (ADS)

Yan, David; Bazant, Martin Z.; Biesheuvel, P. M.; Pugh, Mary C.; Dawson, Francis P.

2017-03-01

Linear sweep and cyclic voltammetry techniques are important tools for electrochemists and have a variety of applications in engineering. Voltammetry has classically been treated with the Randles-Sevcik equation, which assumes an electroneutral supported electrolyte. In this paper, we provide a comprehensive mathematical theory of voltammetry in electrochemical cells with unsupported electrolytes and for other situations where diffuse charge effects play a role, and present analytical and simulated solutions of the time-dependent Poisson-Nernst-Planck equations with generalized Frumkin-Butler-Volmer boundary conditions for a 1:1 electrolyte and a simple reaction. Using these solutions, we construct theoretical and simulated current-voltage curves for liquid and solid thin films, membranes with fixed background charge, and cells with blocking electrodes. The full range of dimensionless parameters is considered, including the dimensionless Debye screening length (scaled to the electrode separation), Damkohler number (ratio of characteristic diffusion and reaction times), and dimensionless sweep rate (scaled to the thermal voltage per diffusion time). The analysis focuses on the coupling of Faradaic reactions and diffuse charge dynamics, although capacitive charging of the electrical double layers is also studied, for early time transients at reactive electrodes and for nonreactive blocking electrodes. Our work highlights cases where diffuse charge effects are important in the context of voltammetry, and illustrates which regimes can be approximated using simple analytical expressions and which require more careful consideration.

Review of Fuel Cell Technologies for Military Land Vehicles

DTIC Science & Technology

2014-09-01

fuel cell technologies for APUs are Proton Exchange Membrane Fuel Cells ( PEMFC ), direct methanol fuel cells and Solid Oxide Fuel Cells (SOFC). The...6 4.2 Proton Exchange Membrane Fuel Cells ( PEMFC ...OEM Original Equipment Manufacturer PEM Proton Exchange Membrane PEMFC Proton Exchange Membrane Fuel Cell SOFC Solid Oxide Fuel Cell TRL Technical

Nanowire membrane-based nanothermite: towards processable and tunable interfacial diffusion for solid state reactions.

PubMed

Yang, Yong; Wang, Peng-peng; Zhang, Zhi-cheng; Liu, Hui-ling; Zhang, Jingchao; Zhuang, Jing; Wang, Xun

2013-01-01

Interfacial diffusion is of great importance in determining the performance of solid-state reactions. For nanometer sized particles, some solid-state reactions can be triggered accidently by mechanical stress owing to their large surface-to-volume ratio compared with the bulk ones. Therefore, a great challenge is the control of interfacial diffusion for solid state reactions, especially for energetic materials. Here we demonstrate, through the example of nanowire-based thermite membrane, that the thermite solid-state reaction can be easily tuned via the introduction of low-surface-energy coating layer. Moreover, this silicon-coated thermite membrane exhibit controlled wetting behavior ranging from superhydrophilic to superhydrophobic and, simultaneously, to significantly reduce the friction sensitivity of thermite membrane. This effect enables to increase interfacial resistance by increasing the amount of coating material. Indeed, our results described here make it possible to tune the solid-state reactions through the manipulation of interfacial diffusion between the reactants.

Nanowire Membrane-based Nanothermite: towards Processable and Tunable Interfacial Diffusion for Solid State Reactions

NASA Astrophysics Data System (ADS)

Yang, Yong; Wang, Peng-Peng; Zhang, Zhi-Cheng; Liu, Hui-Ling; Zhang, Jingchao; Zhuang, Jing; Wang, Xun

2013-04-01

Interfacial diffusion is of great importance in determining the performance of solid-state reactions. For nanometer sized particles, some solid-state reactions can be triggered accidently by mechanical stress owing to their large surface-to-volume ratio compared with the bulk ones. Therefore, a great challenge is the control of interfacial diffusion for solid state reactions, especially for energetic materials. Here we demonstrate, through the example of nanowire-based thermite membrane, that the thermite solid-state reaction can be easily tuned via the introduction of low-surface-energy coating layer. Moreover, this silicon-coated thermite membrane exhibit controlled wetting behavior ranging from superhydrophilic to superhydrophobic and, simultaneously, to significantly reduce the friction sensitivity of thermite membrane. This effect enables to increase interfacial resistance by increasing the amount of coating material. Indeed, our results described here make it possible to tune the solid-state reactions through the manipulation of interfacial diffusion between the reactants.

Solid state NMR: The essential technology for helical membrane protein structural characterization

PubMed Central

Cross, Timothy A.; Ekanayake, Vindana; Paulino, Joana; Wright, Anna

2014-01-01

NMR spectroscopy of helical membrane proteins has been very challenging on multiple fronts. The expression and purification of these proteins while maintaining functionality has consumed countless graduate student hours. Sample preparations have depended on whether solution or solid-state NMR spectroscopy was to be performed – neither have been easy. In recent years it has become increasingly apparent that membrane mimic environments influence the structural result. Indeed, in these recent years we have rediscovered that Nobel laureate, Christian Anfinsen, did not say that protein structure was exclusively dictated by the amino acid sequence, but rather by the sequence in a given environment (Anfinsen, 1973) [106]. The environment matters, molecular interactions with the membrane environment are significant and many examples of distorted, non-native membrane protein structures have recently been documented in the literature. However, solid-state NMR structures of helical membrane proteins in proteoliposomes and bilayers are proving to be native structures that permit a high resolution characterization of their functional states. Indeed, solid-state NMR is uniquely able to characterize helical membrane protein structures in lipid environments without detergents. Recent progress in expression, purification, reconstitution, sample preparation and in the solid-state NMR spectroscopy of both oriented samples and magic angle spinning samples has demonstrated that helical membrane protein structures can be achieved in a timely fashion. Indeed, this is a spectacular opportunity for the NMR community to have a major impact on biomedical research through the solid-state NMR spectroscopy of these proteins. PMID:24412099

Solid state NMR: The essential technology for helical membrane protein structural characterization

NASA Astrophysics Data System (ADS)

Cross, Timothy A.; Ekanayake, Vindana; Paulino, Joana; Wright, Anna

2014-02-01

NMR spectroscopy of helical membrane proteins has been very challenging on multiple fronts. The expression and purification of these proteins while maintaining functionality has consumed countless graduate student hours. Sample preparations have depended on whether solution or solid-state NMR spectroscopy was to be performed - neither have been easy. In recent years it has become increasingly apparent that membrane mimic environments influence the structural result. Indeed, in these recent years we have rediscovered that Nobel laureate, Christian Anfinsen, did not say that protein structure was exclusively dictated by the amino acid sequence, but rather by the sequence in a given environment (Anfinsen, 1973) [106]. The environment matters, molecular interactions with the membrane environment are significant and many examples of distorted, non-native membrane protein structures have recently been documented in the literature. However, solid-state NMR structures of helical membrane proteins in proteoliposomes and bilayers are proving to be native structures that permit a high resolution characterization of their functional states. Indeed, solid-state NMR is uniquely able to characterize helical membrane protein structures in lipid environments without detergents. Recent progress in expression, purification, reconstitution, sample preparation and in the solid-state NMR spectroscopy of both oriented samples and magic angle spinning samples has demonstrated that helical membrane protein structures can be achieved in a timely fashion. Indeed, this is a spectacular opportunity for the NMR community to have a major impact on biomedical research through the solid-state NMR spectroscopy of these proteins.

Visualization of flow during cleaning process on a liquid nanofibrous filter

NASA Astrophysics Data System (ADS)

Bílek, P.

2017-10-01

This paper deals with visualization of flow during cleaning process on a nanofibrous filter. Cleaning of a filter is very important part of the filtration process which extends lifetime of the filter and improve filtration properties. Cleaning is carried out on flat-sheet filters, where particles are deposited on the filter surface and form a filtration cake. The cleaning process dislodges the deposited filtration cake, which is loose from the membrane surface to the retentate flow. The blocked pores in the filter are opened again and hydrodynamic properties are restored. The presented optical method enables to see flow behaviour in a thin laser sheet on the inlet side of a tested filter during the cleaning process. The local concentration of solid particles is possible to estimate and achieve new information about the cleaning process. In the article is described the cleaning process on nanofibrous membranes for waste water treatment. The hydrodynamic data were compared to the images of the cleaning process.

Rapid ultrasensitive single particle surface-enhanced Raman spectroscopy using metallic nanopores.

PubMed

Cecchini, Michael P; Wiener, Aeneas; Turek, Vladimir A; Chon, Hyangh; Lee, Sangyeop; Ivanov, Aleksandar P; McComb, David W; Choo, Jaebum; Albrecht, Tim; Maier, Stefan A; Edel, Joshua B

2013-10-09

Nanopore sensors embedded within thin dielectric membranes have been gaining significant interest due to their single molecule sensitivity and compatibility of detecting a large range of analytes, from DNA and proteins, to small molecules and particles. Building on this concept we utilize a metallic Au solid-state membrane to translocate and rapidly detect single Au nanoparticles (NPs) functionalized with 589 dye molecules using surface-enhanced resonance Raman spectroscopy (SERRS). We show that, due to the plasmonic coupling between the Au metallic nanopore surface and the NP, signal intensities are enhanced when probing analyte molecules bound to the NP surface. Although not single molecule, this nanopore sensing scheme benefits from the ability of SERRS to provide rich vibrational information on the analyte, improving on current nanopore-based electrical and optical detection techniques. We show that the full vibrational spectrum of the analyte can be detected with ultrahigh spectral sensitivity and a rapid temporal resolution of 880 μs.

Opening of K+ channels by capacitive stimulation from silicon chip

NASA Astrophysics Data System (ADS)

Ulbrich, M. H.; Fromherz, P.

2005-10-01

The development of stable neuroelectronic systems requires a stimulation of nerve cells from semiconductor devices without electrochemical effects at the electrolyte/solid interface and without damage of the cell membrane. The interaction must rely on a reversible opening of voltage-gated ion channels by capacitive coupling. In a proof-of-principle experiment, we demonstrate that Kv1.3 potassium channels expressed in HEK293 cells can be opened from an electrolyte/oxide/silicon (EOS) capacitor. A sufficient strength of electrical coupling is achieved by insulating silicon with a thin film of TiO2 to achieve a high capacitance and by removing NaCl from the electrolyte to enhance the resistance of the cell-chip contact. When a decaying voltage ramp is applied to the EOS capacitor, an outward current through the attached cell membrane is observed that is specific for Kv1.3 channels. An open probability up to fifty percent is estimated by comparison with a numerical simulation of the cell-chip contact.

Numerical and Experimental Dynamic Characteristics of Thin-Film Membranes

NASA Technical Reports Server (NTRS)

Young, Leyland G.; Ramanathan, Suresh; Hu, Jia-Zhu; Pai, P. Frank

2004-01-01

Presented is a total-Lagrangian displacement-based non-linear finite-element model of thin-film membranes for static and dynamic large-displacement analyses. The membrane theory fully accounts for geometric non-linearities. Fully non-linear static analysis followed by linear modal analysis is performed for an inflated circular cylindrical Kapton membrane tube under different pressures, and for a rectangular membrane under different tension loads at four comers. Finite element results show that shell modes dominate the dynamics of the inflated tube when the inflation pressure is low, and that vibration modes localized along four edges dominate the dynamics of the rectangular membrane. Numerical dynamic characteristics of the two membrane structures were experimentally verified using a Polytec PI PSV-200 scanning laser vibrometer and an EAGLE-500 8-camera motion analysis system.

Spherical indentation of a freestanding circular membrane revisited: Analytical solutions and experiments

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

Jin, Congrui; Davoodabadi, Ali; Li, Jianlin

Because of the development of novel micro-fabrication techniques to produce ultra-thin materials and increasing interest in thin biological membranes, in recent years, the mechanical characterization of thin films has received a significant amount of attention. To provide a more accurate solution for the relationship among contact radius, load and deflection, the fundamental and widely applicable problem of spherical indentation of a freestanding circular membrane have been revisited. The work presented here significantly extends the previous contributions by providing an exact analytical solution to the governing equations of Föppl–Hecky membrane indented by a frictionless spherical indenter. In this study, experiments ofmore » spherical indentation has been performed, and the exact analytical solution presented in this article is compared against experimental data from existing literature as well as our own experimental results.« less

Spherical indentation of a freestanding circular membrane revisited: Analytical solutions and experiments

DOE PAGES

Jin, Congrui; Davoodabadi, Ali; Li, Jianlin; ...

2017-01-11

Because of the development of novel micro-fabrication techniques to produce ultra-thin materials and increasing interest in thin biological membranes, in recent years, the mechanical characterization of thin films has received a significant amount of attention. To provide a more accurate solution for the relationship among contact radius, load and deflection, the fundamental and widely applicable problem of spherical indentation of a freestanding circular membrane have been revisited. The work presented here significantly extends the previous contributions by providing an exact analytical solution to the governing equations of Föppl–Hecky membrane indented by a frictionless spherical indenter. In this study, experiments ofmore » spherical indentation has been performed, and the exact analytical solution presented in this article is compared against experimental data from existing literature as well as our own experimental results.« less

Structurally distinct membrane nanotubes between human macrophages support long-distance vesicular traffic or surfing of bacteria.

PubMed

Onfelt, Björn; Nedvetzki, Shlomo; Benninger, Richard K P; Purbhoo, Marco A; Sowinski, Stefanie; Hume, Alistair N; Seabra, Miguel C; Neil, Mark A A; French, Paul M W; Davis, Daniel M

2006-12-15

We report that two classes of membrane nanotubes between human monocyte-derived macrophages can be distinguished by their cytoskeletal structure and their functional properties. Thin membrane nanotubes contained only F-actin, whereas thicker nanotubes, i.e., those > approximately 0.7 microm in diameter, contained both F-actin and microtubules. Bacteria could be trapped and surf along thin, but not thick, membrane nanotubes toward connected macrophage cell bodies. Once at the cell body, bacteria could then be phagocytosed. The movement of bacteria is aided by a constitutive flow of the nanotube surface because streptavidin-coated beads were similarly able to traffic along nanotubes between surface-biotinylated macrophages. Mitochondria and intracellular vesicles, including late endosomes and lysosomes, could be detected within thick, but not thin, membrane nanotubes. Analysis from kymographs demonstrated that vesicles moved in a stepwise, bidirectional manner at approximately 1 microm/s, consistent with their traffic being mediated by the microtubules found only in thick nanotubes. Vesicular traffic in thick nanotubes and surfing of beads along thin nanotubes were both stopped upon the addition of azide, demonstrating that both processes require ATP. However, microtubule destabilizing agents colchicine or nocodazole abrogated vesicular transport but not the flow of the nanotube surface, confirming that distinct cytoskeletal structures of nanotubes give rise to different functional properties. Thus, membrane nanotubes between macrophages are more complex than unvarying ubiquitous membrane tethers and facilitate several means for distal interactions between immune cells.

Hydrodynamic flow in the vicinity of a nanopore induced by an applied voltage

PubMed Central

Mao, Mao; Ghosal, Sandip; Hu, Guohui

2013-01-01

Continuum simulation is employed to study ion transport and fluid flow through a nanopore in a solid-state membrane under an applied potential drop. Results show the existence of concentration polarization layers on the surfaces of the membrane. The nonuniformity of the ionic distribution gives rise to an electric pressure that drives vortical motion in the fluid. There is also a net hydrodynamic flow through the nanopore due to an asymmetry induced by the membrane surface charge. The qualitative behavior is similar to that observed in a previous study using molecular dynamic simulations. The current–voltage characteristics show some nonlinear features but are not greatly affected by the hydrodynamic flow in the parameter regime studied. In the limit of thin Debye layers, the electric resistance of the system can be characterized using an equivalent circuit with lumped parameters. Generation of vorticity can be understood qualitatively from elementary considerations of the Maxwell stresses. However, the flow strength is a strongly nonlinear function of the applied field. Combination of electrophoretic and hydrodynamic effects can lead to ion selectivity in terms of valences and this could have some practical applications in separations. PMID:23689946

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

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

William C. Conner

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.

Grain sorghum stillage recycling: Effect on ethanol yield and stillage quality.

PubMed

Egg, R P; Sweeten, J M; Coble, C G

1985-12-01

Stillage obtained from ethanol production of grain sorghum was separated into two fractions: thin stillage and wet solids. A portion of the thin stillage was recycled as cooking water in subsequent fermentation runs using both bench- and full-scale ethanol production plants. When thin stillage replaced 50-75% of the cooking water, large increases occurred in solids content, COD, and EC of the resulting thin stillage. It was found that while the volume of thin stillage requiring treatment or disposal was reduced, there was little reduction in the total pollutant load. Stillage rcycling had little effect on the quality of the stillage wet solids fraction. At the high levels of stillage recycle used, ethanol yield was reduced after three to five runs of consecutive recycling.

Thin film production method and apparatus

DOEpatents

Loutfy, Raouf O.; Moravsky, Alexander P.; Hassen, Charles N.

2010-08-10

A method for forming a thin film material which comprises depositing solid particles from a flowing suspension or aerosol onto a filter and next adhering the solid particles to a second substrate using an adhesive.

Comparison of biofouling mechanisms between cellulose triacetate (CTA) and thin-film composite (TFC) polyamide forward osmosis membranes in osmotic membrane bioreactors.

PubMed

Wang, Xinhua; Zhao, Yanxiao; Yuan, Bo; Wang, Zhiwei; Li, Xiufen; Ren, Yueping

2016-02-01

There are two types of popular forward osmosis (FO) membrane materials applied for researches on FO process, cellulose triacetate (CTA) and thin film composite (TFC) polyamide. However, performance and fouling mechanisms of commercial TFC FO membrane in osmotic membrane bioreactors (OMBRs) are still unknown. In current study, its biofouling behaviors in OMBRs were investigated and further compared to the CTA FO membrane. The results indicated that β-D-glucopyranose polysaccharides and microorganisms accounted for approximately 77% of total biovolume on the CTA FO membrane while β-D-glucopyranose polysaccharides (biovolume ratio of 81.1%) were the only dominant biofoulants on the TFC FO membrane. The analyses on the biofouling structure implied that a tighter biofouling layer with a larger biovolume was formed on the CTA FO membrane. The differences in biofouling behaviors including biofoulants composition and biofouling structure between CTA and TFC FO membranes were attributed to different membrane surface properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

Corner Wrinkling at a Square Membrane Due to Symmetric Mechanical Loads

NASA Technical Reports Server (NTRS)

Blandino, Joseph R.; Johnston, John D.; Dharamsi, Urmil K.; Brodeur, Stephen J. (Technical Monitor)

2001-01-01

Thin-film membrane structures are under consideration for use in many future gossamer spacecraft systems. Examples include sunshields for large aperture telescopes, solar sails, and membrane optics. The development of capabilities for testing and analyzing pre-tensioned, thin film membrane structures is an important and challenging aspect of gossamer spacecraft technology development. This paper presents results from experimental and computational studies performed to characterize the wrinkling behavior of thin-fi[m membranes under mechanical loading. The test article is a 500 mm square membrane subjected to symmetric comer loads. Data is presented for loads ranging from 0.49 N to 4.91 N. The experimental results show that as the load increases the number of wrinkles increases, while the wrinkle amplitude decreases. The computational model uses a finite element implementation of Stein-Hedgepeth membrane wrinkling theory to predict the behavior of the membrane. Comparisons were made with experimental results for the wrinkle angle and wrinkled region. There was reasonably good agreement between the measured wrinkle angle and the predicted directions of the major principle stresses. The shape of the wrinkle region predicted by the finite element model matches that observed in the experiments; however, the size of the predicted region is smaller than that determined in the experiments.

High-resolution orientation and depth of insertion of the voltage-sensing S4 helix of a potassium channel in lipid bilayers.

PubMed

Doherty, Tim; Su, Yongchao; Hong, Mei

2010-08-27

The opening and closing of voltage-gated potassium (Kv) channels are controlled by several conserved Arg residues in the S4 helix of the voltage-sensing domain. The interaction of these positively charged Arg residues with the lipid membrane has been of intense interest for understanding how membrane proteins fold to allow charged residues to insert into lipid bilayers against free-energy barriers. Using solid-state NMR, we have now determined the orientation and insertion depth of the S4 peptide of the KvAP channel in lipid bilayers. Two-dimensional (15)N correlation experiments of macroscopically oriented S4 peptide in phospholipid bilayers revealed a tilt angle of 40 degrees and two possible rotation angles differing by 180 degrees around the helix axis. Remarkably, the tilt angle and one of the two rotation angles are identical to those of the S4 helix in the intact voltage-sensing domain, suggesting that interactions between the S4 segment and other helices of the voltage-sensing domain are not essential for the membrane topology of the S4 helix. (13)C-(31)P distances between the S4 backbone and the lipid (31)P indicate a approximately 9 A local thinning and 2 A average thinning of the DMPC (1,2-dimyristoyl-sn-glycero-3-phosphochloline)/DMPG (1,2-dimyristoyl-sn-glycero-3-phosphatidylglycerol) bilayer, consistent with neutron diffraction data. Moreover, a short distance of 4.6 A from the guanidinium C(zeta) of the second Arg to (31)P indicates the existence of guanidinium phosphate hydrogen bonding and salt bridges. These data suggest that the structure of the Kv gating helix is mainly determined by protein-lipid interactions instead of interhelical protein-protein interactions, and the S4 amino acid sequence encodes sufficient information for the membrane topology of this crucial gating helix. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Fabrication of high-quality superconductor-insulator-superconductor junctions on thin SiN membranes

NASA Technical Reports Server (NTRS)

Garcia, Edouard; Jacobson, Brian R.; Hu, Qing

1993-01-01

We have successfully fabricated high-quality and high-current density superconductor-insulator-superconductor (SIS) junctions on freestanding thin silicon nitride (SIN) membranes. These devices can be used in a novel millimeter-wave and THz receiver system which is made using micromachining. The SIS junctions with planar antennas were fabricated first on a silicon wafer covered with a SiN membrane, the Si wafer underneath was then etched away using an anisotropic KOH etchant. The current-voltage characteristics of the SIS junctions remained unchanged after the whole process, and the junctions and the membrane survived thermal cycling.

Advanced solid elements for sheet metal forming simulation

NASA Astrophysics Data System (ADS)

Mataix, Vicente; Rossi, Riccardo; Oñate, Eugenio; Flores, Fernando G.

2016-08-01

The solid-shells are an attractive kind of element for the simulation of forming processes, due to the fact that any kind of generic 3D constitutive law can be employed without any additional hypothesis. The present work consists in the improvement of a triangular prism solid-shell originally developed by Flores[2, 3]. The solid-shell can be used in the analysis of thin/thick shell, undergoing large deformations. The element is formulated in total Lagrangian formulation, and employs the neighbour (adjacent) elements to perform a local patch to enrich the displacement field. In the original formulation a modified right Cauchy-Green deformation tensor (C) is obtained; in the present work a modified deformation gradient (F) is obtained, which allows to generalise the methodology and allows to employ the Pull-Back and Push-Forwards operations. The element is based in three modifications: (a) a classical assumed strain approach for transverse shear strains (b) an assumed strain approach for the in-plane components using information from neighbour elements and (c) an averaging of the volumetric strain over the element. The objective is to use this type of elements for the simulation of shells avoiding transverse shear locking, improving the membrane behaviour of the in-plane triangle and to handle quasi-incompressible materials or materials with isochoric plastic flow.

Polyurethane Ionophore-Based Thin Layer Membranes for Voltammetric Ion Activity Sensing.

PubMed

Cuartero, Maria; Crespo, Gaston A; Bakker, Eric

2016-06-07

We report on a plasticized polyurethane ionophore-based thin film material (of hundreds of nanometer thickness) for simultaneous voltammetric multianalyte ion activity detection triggered by the oxidation/reduction of an underlying poly(3-octylthiophene) film. This material provides excellent mechanical, physical, and chemical robustness compared to other polymers. Polyurethane films did not exhibit leaching of lipophilic additives after rinsing with a direct water jet and exhibited resistance to detachment from the underlying electrode surface, resulting in a voltammetric current response with less than <1.5% RSD variation (n = 50). In contrast, plasticized poly(vinyl chloride), polystyrene, and poly(acrylate) ionophore-based membranes of the same thickness and composition exhibited a significant deterioration of the signal after identical treatment. While previously reported works emphasized fundamental advancement of multi-ion detection with multi-ionophore-based thin films, polyurethane thin membranes allow one to achieve real world measurements without sacrificing analytical performance. Indeed, polyurethane membranes are demonstrated to be useful for the simultaneous determination of potassium and lithium in undiluted human serum and blood with attractive precision.

Water ball collision

NASA Technical Reports Server (NTRS)

Fujimoto, K.

1986-01-01

What happens if a stainless steel ball hits a water ball in the weightless space ot the Universe? In other words, it was the objective of our experiments in the Space to observe the surface tension of liquid by means of making a solid collide with a liquid. Place a small volume of water between 2 glass sheets to make a thin water membrane: the 2 glass sheets cannot be separated unless an enormous force is applied. It is obvious from this phenomenom that the surface tension of water is far greater than presumed. On Earth, however, it is impossible in most cases to observe only the surface tension of liquid, because gravity always acts on the surface tension. Water and stainless steel balls were chosen the liquid and solids for the experiments. Because water is the liquid most familiar to us, its properties are well known. And it is also of great interest to compare its properties on the Earth with those in the weightless space.

Characteristics of heat transfer fouling of thin stillage using model thin stillage and evaporator concentrates

NASA Astrophysics Data System (ADS)

Challa, Ravi Kumar

The US fuel ethanol demand was 50.3 billion liters (13.3 billion gallons) in 2012. Corn ethanol was produced primarily by dry grind process. Heat transfer equipment fouling occurs during corn ethanol production and increases the operating expenses of ethanol plants. Following ethanol distillation, unfermentables are centrifuged to separate solids as wet grains and liquid fraction as thin stillage. Evaporator fouling occurs during thin stillage concentration to syrup and decreases evaporator performance. Evaporators need to be shutdown to clean the deposits from the evaporator surfaces. Scheduled and unscheduled evaporator shutdowns decrease process throughput and results in production losses. This research were aimed at investigating thin stillage fouling characteristics using an annular probe at conditions similar to an evaporator in a corn ethanol production plant. Fouling characteristics of commercial thin stillage and model thin stillage were studied as a function of bulk fluid temperature and heat transfer surface temperature. Experiments were conducted by circulating thin stillage or carbohydrate mixtures in a loop through the test section which consisted of an annular fouling probe while maintaining a constant heat flux by electrical heating and fluid flow rate. The change in fouling resistance with time was measured. Fouling curves obtained for thin stillage and concentrated thin stillage were linear with time but no induction periods were observed. Fouling rates for concentrated thin stillage were higher compared to commercial thin stillage due to the increase in solid concentration. Fouling rates for oil skimmed and unskimmed concentrated thin stillage were similar but lower than concentrated thin stillage at 10% solids concentration. Addition of post fermentation corn oil to commercial thin stillage at 0.5% increments increased the fouling rates up to 1% concentration but decreased at 1.5%. As thin stillage is composed of carbohydrates, protein, lipid, fiber and minerals, simulated thin stillage was prepared with carbohydrate mixtures and tested for fouling rates. Induction period, maximum fouling resistance and mean fouling rates were determined. Two experiments were performed with two varieties of starch, waxy and high amylose and short chain carbohydrates, corn syrup solids and glucose. Interaction effects of glucose with starch varieties were studied. In the first experiment, short chain carbohydrates individual and interaction effects with starch were studied. For mixtures prepared from glucose and corn syrup solids, no fouling was observed. Mixtures prepared from starch, a long glucose polymer, showed marked fouling. Corn syrup solids and glucose addition to pure starch decreased the mean fouling rates and maximum fouling resistances. Between corn syrup solids and glucose, starch fouling rates were reduced with addition of glucose. Induction periods of pure mixtures of either glucose or corn syrup solids were longer than the test period (5 h). Pure starch mixture had no induction period. Maximum fouling resistance was higher for mixtures with higher concentration of longer polymers. Waxy starch had a longer induction period than high amylose starch. Maximum fouling resistance was higher for waxy than high amylose starch. Addition of glucose to waxy or high amylose starch increased induction period of mixtures longer than 5 h test period. It appears that the bulk fluid temperature plays an important role on carbohydrate mixture fouling rates. Higher bulk fluid temperatures increased the initial fouling rates of the carbohydrate mixtures. Carbohydrate type, depending on the polymer length, influenced the deposit formation. Longer chain carbohydrate, starch, had higher fouling rates compared to shorter carbohydrates such as glucose and corn syrup solids. For insoluble carbohydrate mixtures, fouling was severe. As carbohydrate solubility increased with bulk fluid temperature, surface reaction increased at probe surface and resulted in deposit formation. Higher surface temperatures eliminated induction periods for thin stillage and fouling was rapid on probe surface.

Structural study of the membrane protein MscL using cell-free expression and solid-state NMR

NASA Astrophysics Data System (ADS)

Abdine, Alaa; Verhoeven, Michiel A.; Park, Kyu-Ho; Ghazi, Alexandre; Guittet, Eric; Berrier, Catherine; Van Heijenoort, Carine; Warschawski, Dror E.

2010-05-01

High-resolution structures of membrane proteins have so far been obtained mostly by X-ray crystallography, on samples where the protein is surrounded by detergent. Recent developments of solid-state NMR have opened the way to a new approach for the study of integral membrane proteins inside a membrane. At the same time, the extension of cell-free expression to the production of membrane proteins allows for the production of proteins tailor made for NMR. We present here an in situ solid-state NMR study of a membrane protein selectively labeled through the use of cell-free expression. The sample consists of MscL (mechano-sensitive channel of large conductance), a 75 kDa pentameric α-helical ion channel from Escherichia coli, reconstituted in a hydrated lipid bilayer. Compared to a uniformly labeled protein sample, the spectral crowding is greatly reduced in the cell-free expressed protein sample. This approach may be a decisive step required for spectral assignment and structure determination of membrane proteins by solid-state NMR.

Microchannel laminated mass exchanger and method of making

DOEpatents

Martin, Peter M [Kennewick, WA; Bennett, Wendy D [Kennewick, WA; Matson, Dean W [Kennewick, WA; Stewart, Donald C [Richland, WA; Drost, Monte K [Pasco, WA; Wegeng, Robert S [Richland, WA; Perez, Joseph M [Richland, WA; Feng, Xiangdong [West Richland, WA; Liu, Jun [West Richland, WA

2003-03-18

The present invention is a microchannel mass exchanger having a first plurality of inner thin sheets and a second plurality of outer thin sheets. The inner thin sheets each have a solid margin around a circumference, the solid margin defining a slot through the inner thin sheet thickness. The outer thin sheets each have at least two header holes on opposite ends and when sandwiching an inner thin sheet. The outer thin sheets further have a mass exchange medium. The assembly forms a closed flow channel assembly wherein fluid enters through one of the header holes into the slot and exits through another of the header holes after contacting the mass exchange medium.

Microchannel laminated mass exchanger and method of making

DOEpatents

Martin, Peter M.; Bennett, Wendy D.; Matson, Dean W.; Stewart, Donald C.; Drost, Monte K.; Wegeng, Robert S.; Perez, Joseph M.; Feng, Xiangdong; Liu, Jun

2000-01-01

The present invention is a microchannel mass exchanger having a first plurality of inner thin sheets and a second plurality of outer thin sheets. The inner thin sheets each have a solid margin around a circumference, the solid margin defining a slot through the inner thin sheet thickness. The outer thin sheets each have at least two header holes on opposite ends and when sandwiching an inner thin sheet. The outer thin sheets further have a mass exchange medium. The assembly forms a closed flow channel assembly wherein fluid enters through one of the header holes into the slot and exits through another of the header holes after contacting the mass exchange medium.

Microchannel laminated mass exchanger and method of making

DOEpatents

Martin, Peter M [Kennewick, WA; Bennett, Wendy D [Kennewick, WA; Matson, Dean W [Kennewick, WA; Stewart, Donald C [Richland, WA; Drost, Monte K [Pasco, WA; Wegeng, Robert S [Richland, WA; Perez, Joseph M [Richland, WA; Feng, Xiangdong [West Richland, WA; Liu, Jun [West Richland, WA

2002-03-05

The present invention is a microchannel mass exchanger having a first plurality of inner thin sheets and a second plurality of outer thin sheets. The inner thin sheets each have a solid margin around a circumference, the solid margin defining a slot through the inner thin sheet thickness. The outer thin sheets each have at least two header holes on opposite ends and when sandwiching an inner thin sheet. The outer thin sheets further have a mass exchange medium. The assembly forms a closed flow channel assembly wherein fluid enters through one of the header holes into the slot and exits through another of the header holes after contacting the mass exchange medium.

More About Thin-Membrane Biosensor

NASA Technical Reports Server (NTRS)

Case, George D.; Worley, Jennings F., III

1994-01-01

Report presents additional information about device described in "Thin-Membrane Sensor With Biochemical Switch" (MFS-26121). Device is modular sensor that puts out electrical signal indicative of chemical or biological agent. Signal produced as membrane-crossing ion current triggered by chemical reaction between agent and recognition protein conjugated to channel blocker. Prototype of biosensor useful in numerous laboratory, industrial, or field applications; such as to detect bacterial toxins in food, to screen for disease-producing micro-organisms, or to warn of toxins or pollutants in air.

Plasma membranes modified by plasma treatment or deposition as solid electrolytes for potential application in solid alkaline fuel cells.

PubMed

Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

2012-07-30

In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol) and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether) polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention) of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane.

Plasma Membranes Modified by Plasma Treatment or Deposition as Solid Electrolytes for Potential Application in Solid Alkaline Fuel Cells

PubMed Central

Reinholdt, Marc; Ilie, Alina; Roualdès, Stéphanie; Frugier, Jérémy; Schieda, Mauricio; Coutanceau, Christophe; Martemianov, Serguei; Flaud, Valérie; Beche, Eric; Durand, Jean

2012-01-01

In the highly competitive market of fuel cells, solid alkaline fuel cells using liquid fuel (such as cheap, non-toxic and non-valorized glycerol) and not requiring noble metal as catalyst seem quite promising. One of the main hurdles for emergence of such a technology is the development of a hydroxide-conducting membrane characterized by both high conductivity and low fuel permeability. Plasma treatments can enable to positively tune the main fuel cell membrane requirements. In this work, commercial ADP-Morgane® fluorinated polymer membranes and a new brand of cross-linked poly(aryl-ether) polymer membranes, named AMELI-32®, both containing quaternary ammonium functionalities, have been modified by argon plasma treatment or triallylamine-based plasma deposit. Under the concomitant etching/cross-linking/oxidation effects inherent to the plasma modification, transport properties (ionic exchange capacity, water uptake, ionic conductivity and fuel retention) of membranes have been improved. Consequently, using plasma modified ADP-Morgane® membrane as electrolyte in a solid alkaline fuel cell operating with glycerol as fuel has allowed increasing the maximum power density by a factor 3 when compared to the untreated membrane. PMID:24958295

Reactive sintering of ceramic lithium ion electrolyte membranes

DOEpatents

Badding, Michael Edward; Dutta, Indrajit; Iyer, Sriram Rangarajan; Kent, Brian Alan; Lonnroth, Nadja Teresia

2017-06-06

Disclosed herein are methods for making a solid lithium ion electrolyte membrane, the methods comprising combining a first reactant chosen from amorphous, glassy, or low melting temperature solid reactants with a second reactant chosen from refractory oxides to form a mixture; heating the mixture to a first temperature to form a homogenized composite, wherein the first temperature is between a glass transition temperature of the first reactant and a crystallization onset temperature of the mixture; milling the homogenized composite to form homogenized particles; casting the homogenized particles to form a green body; and sintering the green body at a second temperature to form a solid membrane. Solid lithium ion electrolyte membranes manufactured according to these methods are also disclosed herein.

Proton conducting membranes for high temperature fuel cells with solid state water free membranes

NASA Technical Reports Server (NTRS)

Narayanan, Sekharipuram R. (Inventor); Yen, Shiao-Pin S. (Inventor)

2006-01-01

A water free, proton conducting membrane for use in a fuel cell is fabricated as a highly conducting sheet of converted solid state organic amine salt, such as converted acid salt of triethylenediamine with two quaternized tertiary nitrogen atoms, combined with a nanoparticulate oxide and a stable binder combined with the converted solid state organic amine salt to form a polymeric electrolyte membrane. In one embodiment the membrane is derived from triethylenediamine sulfate, hydrogen phosphate or trifiate, an oxoanion with at least one ionizable hydrogen, organic tertiary amine bisulfate, polymeric quaternized amine bisulfate or phosphate, or polymeric organic compounds with quaternizable nitrogen combined with Nafion to form an intimate network with ionic interactions.

Nanowire Membrane-based Nanothermite: towards Processable and Tunable Interfacial Diffusion for Solid State Reactions

PubMed Central

Yang, Yong; Wang, Peng-peng; Zhang, Zhi-cheng; Liu, Hui-ling; Zhang, Jingchao; Zhuang, Jing; Wang, Xun

2013-01-01

Interfacial diffusion is of great importance in determining the performance of solid-state reactions. For nanometer sized particles, some solid-state reactions can be triggered accidently by mechanical stress owing to their large surface-to-volume ratio compared with the bulk ones. Therefore, a great challenge is the control of interfacial diffusion for solid state reactions, especially for energetic materials. Here we demonstrate, through the example of nanowire-based thermite membrane, that the thermite solid-state reaction can be easily tuned via the introduction of low-surface-energy coating layer. Moreover, this silicon-coated thermite membrane exhibit controlled wetting behavior ranging from superhydrophilic to superhydrophobic and, simultaneously, to significantly reduce the friction sensitivity of thermite membrane. This effect enables to increase interfacial resistance by increasing the amount of coating material. Indeed, our results described here make it possible to tune the solid-state reactions through the manipulation of interfacial diffusion between the reactants. PMID:23603809

Finite Rotation Analysis of Highly Thin and Flexible Structures

NASA Technical Reports Server (NTRS)

Clarke, Greg V.; Lee, Keejoo; Lee, Sung W.; Broduer, Stephen J. (Technical Monitor)

2001-01-01

Deployable space structures such as sunshields and solar sails are extremely thin and highly flexible with limited bending rigidity. For analytical investigation of their responses during deployment and operation in space, these structures can be modeled as thin shells. The present work examines the applicability of the solid shell element formulation to modeling of deployable space structures. The solid shell element formulation that models a shell as a three-dimensional solid is convenient in that no rotational parameters are needed for the description of kinematics of deformation. However, shell elements may suffer from element locking as the thickness becomes smaller unless special care is taken. It is shown that, when combined with the assumed strain formulation, the solid shell element formulation results in finite element models that are free of locking even for extremely thin structures. Accordingly, they can be used for analysis of highly flexible space structures undergoing geometrically nonlinear finite rotations.

Thin graphite bipolar plate with associated gaskets and carbon cloth flow-field for use in an ionomer membrane fuel cell

DOEpatents

Marchetti, George A.

2003-01-03

The present invention comprises a thin graphite plate with associated gaskets and pieces of carbon cloth that comprise a flow-field. The plate, gaskets and flow-field comprise a "plate and gasket assembly" for use in an ionomer membrane fuel cell, fuel cell stack or battery.

Electro-convective versus electroosmotic instability in concentration polarization.

PubMed

Rubinstein, Isaak; Zaltzman, Boris

2007-10-31

Electro-convection is reviewed as a mechanism of mixing in the diffusion layer of a strong electrolyte adjacent to a charge-selective solid, such as an ion exchange (electrodialysis) membrane or an electrode. Two types of electro-convection in strong electrolytes may be distinguished: bulk electro-convection, due to the action of the electric field upon the residual space charge of a quasi-electro-neutral bulk solution, and convection induced by electroosmotic slip, due to electric forces acting in the thin electric double layer of either quasi-equilibrium or non-equilibrium type near the solid/liquid interface. According to recent studies, the latter appears to be the likely source of mixing in the diffusion layer, leading to 'over-limiting' conductance in electrodialysis. Electro-convection near a planar uniform charge selective solid/liquid interface sets on as a result of hydrodynamic instability of one-dimensional steady state electric conduction through such an interface. We compare the results of linear stability analysis obtained for instabilities of this kind appearing in the full electro-convective and limiting non-equilibrium electroosmotic formulations. The short- and long-wave aspects of these instabilities are discussed along with the wave number selection principles.

Inkjet printing of nanoporous gold electrode arrays on cellulose membranes for high-sensitive paper-like electrochemical oxygen sensors using ionic liquid electrolytes.

PubMed

Hu, Chengguo; Bai, Xiaoyun; Wang, Yingkai; Jin, Wei; Zhang, Xuan; Hu, Shengshui

2012-04-17

A simple approach to the mass production of nanoporous gold electrode arrays on cellulose membranes for electrochemical sensing of oxygen using ionic liquid (IL) electrolytes was established. The approach, combining the inkjet printing of gold nanoparticle (GNP) patterns with the self-catalytic growth of these patterns into conducting layers, can fabricate hundreds of self-designed gold arrays on cellulose membranes within several hours using an inexpensive inkjet printer. The resulting paper-based gold electrode arrays (PGEAs) had several unique properties as thin-film sensor platforms, including good conductivity, excellent flexibility, high integration, and low cost. The porous nature of PGEAs also allowed the addition of electrolytes from the back cellulose membrane side and controllably produced large three-phase electrolyte/electrode/gas interfaces at the front electrode side. A novel paper-based solid-state electrochemical oxygen (O(2)) sensor was therefore developed using an IL electrolyte, 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF(6)). The sensor looked like a piece of paper but possessed high sensitivity for O(2) in a linear range from 0.054 to 0.177 v/v %, along with a low detection limit of 0.0075% and a short response time of less than 10 s, foreseeing its promising applications in developing cost-effective and environment-friendly paper-based electrochemical gas sensors.

Thin-Film Solid Oxide Fuel Cells

NASA Technical Reports Server (NTRS)

Chen, Xin; Wu, Nai-Juan; Ignatiev, Alex

2009-01-01

The development of thin-film solid oxide fuel cells (TFSOFCs) and a method of fabricating them have progressed to the prototype stage. This can result in the reduction of mass, volume, and the cost of materials for a given power level.

Amine Enrichment of Thin-Film Composite Membranes via Low Pressure Plasma Polymerization for Antimicrobial Adhesion.

PubMed

Reis, Rackel; Dumée, Ludovic F; He, Li; She, Fenghua; Orbell, John D; Winther-Jensen, Bjorn; Duke, Mikel C

2015-07-15

Thin-film composite membranes, primarily based on poly(amide) (PA) semipermeable materials, are nowadays the dominant technology used in pressure driven water desalination systems. Despite offering superior water permeation and salt selectivity, their surface properties, such as their charge and roughness, cannot be extensively tuned due to the intrinsic fabrication process of the membranes by interfacial polymerization. The alteration of these properties would lead to a better control of the materials surface zeta potential, which is critical to finely tune selectivity and enhance the membrane materials stability when exposed to complex industrial waste streams. Low pressure plasma was employed to introduce amine functionalities onto the PA surface of commercially available thin-film composite (TFC) membranes. Morphological changes after plasma polymerization were analyzed by SEM and AFM, and average surface roughness decreased by 29%. Amine enrichment provided isoelectric point changes from pH 3.7 to 5.2 for 5 to 15 min of plasma polymerization time. Synchrotron FTIR mappings of the amine-modified surface indicated the addition of a discrete 60 nm film to the PA layer. Furthermore, metal affinity was confirmed by the enhanced binding of silver to the modified surface, supported by an increased antimicrobial functionality with demonstrable elimination of E. coli growth. Essential salt rejection was shown minimally compromised for faster polymerization processes. Plasma polymerization is therefore a viable route to producing functional amine enriched thin-film composite PA membrane surfaces.

Membranes with highly ordered straight nanopores by selective swelling of fast perpendicularly aligned block copolymers.

PubMed

Yin, Jun; Yao, Xueping; Liou, Jiun-You; Sun, Wei; Sun, Ya-Sen; Wang, Yong

2013-11-26

Membranes with uniform, straight nanopores have important applications in diverse fields, but their application is limited by the lack of efficient producing methods with high controllability. In this work, we reported on an extremely simple and efficient strategy to produce such well-defined membranes. We demonstrated that neutral solvents were capable of annealing amphiphilic block copolymer (BCP) films of polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) with thicknesses up to 600 nm to the perpendicular orientation within 1 min. Annealing in neutral solvents was also effective to the perpendicular alignment of block copolymers with very high molecular weights, e.g., 362 000 Da. Remarkably, simply by immersing the annealed BCP films in hot ethanol followed by drying in air, the originally dense BCP films were nondestructively converted into porous membranes containing highly ordered, straight nanopores traversing the entire thickness of the membrane (up to 1.1 μm). Grazing incident small-angle X-ray spectroscopy confirmed the hexagonal ordering of the nanopores over large areas. We found that the overflow of P2VP chains from their reservoir P2VP cylinders and the deformation of the PS matrix in the swelling process contributed to the transformation of the solid P2VP cylinders to empty straight pores. The pore diameters can be tuned by either changing the swelling temperatures or depositing thin layers of metal oxides on the preformed membranes via atomic layer deposition with a subnanometer accuracy. To demonstrate the application of the obtained porous membranes, we used them as templates and produced centimeter-scale arrays of aligned nanotubes of metal oxides with finely tunable wall thicknesses.

Optimization of a Nafion Membrane-Based System for Removal of Chloride and Fluoride from Lunar Regolith-Derived Water

NASA Technical Reports Server (NTRS)

Anthony, Stephen M.; Santiago-Maldonado, Edgardo; Captain, James G.; Pawate, Ashtamurthy S.; Kenis, Paul J. A.

2012-01-01

A long-term human presence in space will require self-sustaining systems capable of producing oxygen and potable water from extraterrestrial sources. Oxygen can be extracted from lunar regolith, and water contaminated with hydrochloric and hydrofluoric acids is produced as an intermediate in this process. We investigated the ability of Nafion proton exchange membranes to remove hydrochloric and hydrofluoric acids from water. The effect of membrane thickness, product stream flow rate, and acid solution temperature and concentration on water flux, acid rejection, and water and acid activity were studied. The conditions that maximized water transport and acid rejection while minimizing resource usage were determined by calculating a figure of merit. Water permeation is highest at high solution temperature and product stream flow rate across thin membranes, while chloride and fluoride permeation are lowest at low acid solution temperature and concentration across thin membranes. The figure of merit varies depending on the starting acid concentration; at low concentration, the figure of merit is highest across a thin membrane, while at high concentration, the figure of merit is highest at low solution temperature. In all cases, the figure of merit increases with increasing product stream flow rate.

Fabrication of polyamide thin-film nanocomposite membranes with enhanced surface charge for nitrate ion removal from water resources.

PubMed

Ghaee, A; Zerafat, M M; Askari, P; Sabbaghi, S; Sadatnia, B

2017-03-01

Exclusion due to membrane surface charge is considered as one of the main separation mechanisms occurring in charged membranes, which can be varied through various approaches to affect membrane rejection performance. In this study, thin-film composite (TFC) polyamide (PA) membranes were fabricated via interfacial polymerization of m-phenylenediamine (m-PDA) and 2,4-diaminobenzene sulfonic acid with trimesoyl chloride (TMC) on a polysulfone sub-layer. The ability of the prepared membrane to remove nitrate ions from water resources has been investigated. In order to improve membrane permeability, zeolite-PA thin film nanocomposite (TFN) membranes were fabricated by incorporating natural zeolite nanoparticles obtained through ball milling of an Iranian natural zeolite powder in the interfacial polymerization process. The size, morphology and specific surface area of the as-obtained nanozeolite were characterized using particle size analysis, FE-SEM and BET. The functional groups, morphology and surface charge of the membrane were characterized using ATR-FTIR, SEM and zeta potential analyses. Also, field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS) were used to determine the distribution of nanozeolite in TFN membranes. The influence of zeolite addition to surface roughness was accessed by atomic force microscopy. The performance of TFC and TFN membranes was evaluated in terms of pure water flux and nitrate rejection. The results showed that in case of sulfonated diamine, nitrate ions rejection was enhanced from 63% to 85% which could be attributed to surface charge enhancement. TFN permeability was almost doubled by the addition of nanozeolite.

Facilitated ion transport in all-solid-state flexible supercapacitors.

PubMed

Choi, Bong Gill; Hong, Jinkee; Hong, Won Hi; Hammond, Paula T; Park, HoSeok

2011-09-27

The realization of highly flexible and all-solid-state energy-storage devices strongly depends on both the electrical properties and mechanical integrity of the constitutive materials and the controlled assembly of electrode and solid electrolyte. Herein we report the preparation of all-solid-state flexible supercapacitors (SCs) through the easy assembly of functionalized reduced graphene oxide (f-RGO) thin films (as electrode) and solvent-cast Nafion electrolyte membranes (as electrolyte and separator). In particular, the f-RGO-based SCs (f-RGO-SCs) showed a 2-fold higher specific capacitance (118.5 F/g at 1 A/g) and rate capability (90% retention at 30 A/g) compared to those of all-solid-state graphene SCs (62.3 F/g at 1A/g and 48% retention at 30 A/g). As proven by the 4-fold faster relaxation of the f-RGO-SCs than that of the RGO-SCs and more capacitive behavior of the former at the low-frequency region, these results were attributed to the facilitated ionic transport at the electrical double layer by means of the interfacial engineering of RGO by Nafion. Moreover, the superiority of all-solid-state flexible f-RGO-SCs was demonstrated by the good performance durability under the 1000 cycles of charging and discharging due to the mechanical integrity as a consequence of the interconnected networking structures. Therefore, this research provides new insight into the rational design and fabrication of all-solid-state flexible energy-storage devices as well as the fundamental understanding of ion and charge transport at the interface. © 2011 American Chemical Society

Characterization of Free-Standing Nano-Membranes by Using Ellipsometry

NASA Astrophysics Data System (ADS)

Park, Sungmo; Lee, Changho; An, Ilsin; Kim, Min-Su; Park, Jin-Goo; Ahn, Jin-ho

2018-04-01

The thickness of the pellicle is only a few tens of microns in extreme ultraviolet lithography (EUVL). This is because the absorption loss by the pellicle is high. Thus, the thickness and contamination on the surface of the EUVL pellicle are important factors for controlling the transmission of EUV light. In this work, we fabricate ultra-thin silicon-nitride membranes for EUVL pellicles and use micro-spot spectroscopic ellipsometry and imaging ellipsometry for characterization. We successfully deduce not only the thickness but also the optical function of the membrane. However, we found that some precautions were required for accurate measurement of the free-standing thin membranes by using ellipsometry. Issues related to the vibration of the membrane and the sensitivity of the measurement are discussed.

Hydrogen production by high-temperature water splitting using electron-conducting membranes

DOEpatents

Lee, Tae H.; Wang, Shuangyan; Dorris, Stephen E.; Balachandran, Uthamalingam

2004-04-27

A device and method for separating water into hydrogen and oxygen is disclosed. A first substantially gas impervious solid electron-conducting membrane for selectively passing hydrogen is provided and spaced from a second substantially gas impervious solid electron-conducting membrane for selectively passing oxygen. When steam is passed between the two membranes at disassociation temperatures the hydrogen from the disassociation of steam selectively and continuously passes through the first membrane and oxygen selectively and continuously passes through the second membrane, thereby continuously driving the disassociation of steam producing hydrogen and oxygen.

Dynamic membrane interactions of antibacterial and antifungal biomolecules, and amyloid peptides, revealed by solid-state NMR spectroscopy.

PubMed

Naito, Akira; Matsumori, Nobuaki; Ramamoorthy, Ayyalusamy

2018-02-01

A variety of biomolecules acting on the cell membrane folds into a biologically active structure in the membrane environment. It is, therefore, important to determine the structures and dynamics of such biomolecules in a membrane environment. While several biophysical techniques are used to obtain low-resolution information, solid-state NMR spectroscopy is one of the most powerful means for determining the structure and dynamics of membrane bound biomolecules such as antibacterial biomolecules and amyloidogenic proteins; unlike X-ray crystallography and solution NMR spectroscopy, applications of solid-state NMR spectroscopy are not limited by non-crystalline, non-soluble nature or molecular size of membrane-associated biomolecules. This review article focuses on the applications of solid-state NMR techniques to study a few selected antibacterial and amyloid peptides. Solid-state NMR studies revealing the membrane inserted bent α-helical structure associated with the hemolytic activity of bee venom melittin and the chemical shift oscillation analysis used to determine the transmembrane structure (with α-helix and 3 10 -helix in the N- and C-termini, respectively) of antibiotic peptide alamethicin are discussed in detail. Oligomerization of an amyloidogenic islet amyloid polypeptide (IAPP, or also known as amylin) resulting from its aggregation in a membrane environment, molecular interactions of the antifungal natural product amphotericin B with ergosterol in lipid bilayers, and the mechanism of lipid raft formation by sphingomyelin studied using solid state NMR methods are also discussed in this review article. This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato. Copyright © 2017 Elsevier B.V. All rights reserved.

Antifouling coatings via plasma polymerization and atom transfer radical polymerization on thin film composite membranes for reverse osmosis

NASA Astrophysics Data System (ADS)

Hirsch, Ulrike; Ruehl, Marco; Teuscher, Nico; Heilmann, Andreas

2018-04-01

A major drawback to otherwise highly efficient membrane-based desalination techniques like reverse osmosis (RO) is the susceptibility of the membranes to biofouling. In this work, a combination of plasma activation, plasma bromination and surface-initiated atom transfer radical polymerization (si-ATRP) of hydrophilic and zwitterionic monomers, namely hydroxyethyl methacrylate (HEMA), 2-methacryloyloxyethyl phosphorylcholine (MPC) and [2-(methacryloyloxy)ethyl]-dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), was applied to generate non-specific, anti-adhesive coatings on thin film composite (TFC) membranes. The antifouling effect of the coatings was shown by short-time batch as well as long-time steady state cultivation experiments with the microorganism Pseudomonas fluorescens. It could be shown that plasma functionalization and polymerization is possible on delicate thin film composite membranes without restricting their filtration performance. All modified membranes showed an increased resistance towards the adhesion of Pseudomonas fluorescens. On average, the biofilm coverage was reduced by 51.4-12.6% (for HEMA, SBMA, and MPC), the highest reduction was monitored for MPC with a biofilm reduction by 85.4%. The hydrophilic coatings applied did not only suppress the adhesion of Pseudomonas fluorescens, but also significantly increase the permeate flux of the membranes relative to uncoated membranes. The stability of the coatings was however not ideal and will have to be improved for future commercial use.

Fabrication of perforated isoporous membranes via a transfer-free strategy: enabling high-resolution separation of cells.

PubMed

Ou, Yang; Lv, Chang-Jiang; Yu, Wei; Mao, Zheng-Wei; Wan, Ling-Shu; Xu, Zhi-Kang

2014-12-24

Thin perforated membranes with ordered pores are ideal barriers for high-resolution and high-efficiency selective transport and separation of biological species. However, for self-assembled thin membranes with a thickness less than several micrometers, an additional step of transferring the membranes onto porous supports is generally required. In this article, we present a facile transfer-free strategy for fabrication of robust perforated composite membranes via the breath figure process, and for the first time, demonstrate the application of the membranes in high-resolution cell separation of yeasts and lactobacilli without external pressure, achieving almost 100% rejection of yeasts and more than 70% recovery of lactobacilli with excellent viability. The avoidance of the transfer step simplifies the fabrication procedure of composite membranes and greatly improves the membrane homogeneity. Moreover, the introduction of an elastic triblock copolymer increases the interfacial strength between the membrane and the support, and allows the preservation of composite membranes in a dry state. Such perforated ordered membranes can also be applied in other size-based separation systems, enabling new opportunities in bioseparation and biosensors.

Highly Sensitive Measurements of 222Rn Diffusion and Emanation

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

Zuzel, Grzegorz

Highly sensitive techniques for determination of the 222Rn emanation from solids and diffusion through different membranes are presented. 222Rn and its daughters are measured via the alpha decays in special proportional counters at the absolute sensitivity of {approx}30 {mu}Bq. Radon diffusion can be measured at the level of {approx}10-13 cm2/s. Several samples were examined, e.g. stainless steel, teflon, various gaskets (emanation and diffusion measurements) and tanks. A combination of measurements of the 222Rn diffusion and emanation of thin nylon foils (used in the Borexino experiment) allowed the determination of 226Ra in the materials of interest at the level of {approx}10-12more » g/g 238U-equivalent.« less

Ion bipolar junction transistors

PubMed Central

Tybrandt, Klas; Larsson, Karin C.; Richter-Dahlfors, Agneta; Berggren, Magnus

2010-01-01

Dynamic control of chemical microenvironments is essential for continued development in numerous fields of life sciences. Such control could be achieved with active chemical circuits for delivery of ions and biomolecules. As the basis for such circuitry, we report a solid-state ion bipolar junction transistor (IBJT) based on conducting polymers and thin films of anion- and cation-selective membranes. The IBJT is the ionic analogue to the conventional semiconductor BJT and is manufactured using standard microfabrication techniques. Transistor characteristics along with a model describing the principle of operation, in which an anionic base current amplifies a cationic collector current, are presented. By employing the IBJT as a bioelectronic circuit element for delivery of the neurotransmitter acetylcholine, its efficacy in modulating neuronal cell signaling is demonstrated. PMID:20479274

Post-deposition annealing temperature dependence TiO{sub 2}-based EGFET pH sensor sensitivity

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

Zulkefle, M. A., E-mail: alhadizulkefle@gmail.com; Rahman, R. A., E-mail: rohanieza.abdrahman@gmail.com; Yusoff, K. A., E-mail: khairul.aimi.yusof@gmail.com

EGFET pH sensor is one type of pH sensor that is used to measure and determine pH of a solution. The sensing membrane of EGFET pH sensor plays vital role in the overall performance of the sensor. This paper studies the effects of different annealing temperature of the TiO{sub 2} sensing membranes towards sensitivity of EGFET pH sensor. Sol-gel spin coating was chosen as TiO{sub 2} deposition techniques since it is cost-effective and produces thin film with uniform thickness. Deposited TiO{sub 2} thin films were then annealed at different annealing temperatures and then were connected to the gate of MOSFETmore » as a part of the EGFET pH sensor structure. The thin films now act as sensing membranes of the EGFET pH sensor and sensitivity of each sensing membrane towards pH was measured. From the results it was determined that sensing membrane annealed at 300 °C gave the highest sensitivity followed by sample annealed at 400 °C and 500 °C.« less

Mechanical characterization of capsule properties using abrupt-step channels

NASA Astrophysics Data System (ADS)

Salsac, Anne-Virginie; Le Goff, Anne; Kaoui, Badr; Barthè-Biesel, Dominique; Biomechanics; Bioengineering Lab Team

2017-11-01

Capsules consisting of a liquid droplet enclosed by a thin polymerized membrane are commonly encountered in nature (cells) or in industrial process (pharmaceutical, cosmetic or food products). The mechanical properties of the capsule wall are essential to guarantee the particle integrity and release of the internal contents when and where necessary. The difficulty is to assess the mechanical properties of the thin membrane. We will show how abrupt-step channels can be used to identify the membrane viscoelastic properties and point of rupture. This can be achieved by using a channel presenting a step change in cross-section and inverting the direction of the flow of the capsule suspension within the tube. To deduce information on the viscoelasticity, we will exploit the relaxation of the capsules as they flow through the expansion. To study membrane rupture, we will instead invert the channel, block the capsules at the neck of the constriction and determine the pressure difference needed for breakup. All the experiments will be conducted on initially spherical capsules with a thin cross-linked protein membrane for a proof of concept.

Thin Film Electrodes with an Integral Current Collection Grid for Use with Solid Electrolytes

NASA Technical Reports Server (NTRS)

Ryan, M. A.; Kisor, A.; Williams, R. M.; Jeffries-Nakamura, B.; O'Connor, D.

1994-01-01

Thin film, high performance electrodes which can operate in high temperature environments are necessary for many devices which use a solid electrolyte. Electrodes of rhodium-tungsten alloy have been deposited on solid electrolyte using photolytic chemical vapor deposition (PCVD). A technique for depositing electrodes and current collection grids simultaneously has been developed using the prenucleation characteristics of PCVD. This technique makes it possible to fabricate electrodes which allow vapor transport through the thin (<1 (micro)m) portions of the electrode while integral thick grid lines improve the electronic conductivity of the electrode, thus improving overall performance.

Ultra-thin nanocrystalline diamond membranes as pressure sensors for harsh environments

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

Janssens, S. D., E-mail: stoffel.d.janssens@gmail.com; Haenen, K., E-mail: ken.haenen@uhasselt.be; IMOMEC, IMEC vzw, Wetenschapspark 1, B-3590 Diepenbeek

2014-02-17

Glass and diamond are suitable materials for harsh environments. Here, a procedure for fabricating ultra-thin nanocrystalline diamond membranes on glass, acting as an electrically insulating substrate, is presented. In order to investigate the pressure sensing properties of such membranes, a circular, highly conductive boron-doped nanocrystalline diamond membrane with a resistivity of 38 mΩ cm, a thickness of 150 nm, and a diameter of 555 μm is fabricated in the middle of a Hall bar structure. During the application of a positive differential pressure under the membrane (0–0.7 bar), four point piezoresistive effect measurements are performed. From these measurements, it can be concluded that the resistancemore » response of the membrane, as a function of differential pressure, is highly linear and sensitive.« less

Effects of Aloe Vera and Chitosan Nanoparticle Thin-Film Membranes on Wound Healing in Full Thickness Infected Wounds with Methicillin Resistant Staphylococcus Aureus.

PubMed

Ranjbar, Reza; Yousefi, Alireza

2018-01-01

To assess effect of Aleo vera with chitosan nanoparticle biofilm on wound healing in full thickness infected wounds with antibiotic resistant gram positive bacteria. Thirty rats were randomized into five groups of six rats each. Group I: Animals with uninfected wounds treated with 0.9% saline solution. Group II: Animals with infected wounds treated with saline. Group III: Animals with infected wounds were dressed with chitosan nanoparticle thin-film membranes. Group IV: Animals with infected wounds were treated topically with Aloe vera and Group V: Animals with infected wounds were treated topically with Aloe vera and dressed with chitosan nanoparticle thin-film membranes. Wound size was measured on 6, 9, 12, 15, 18 and 21days after surgery. Microbiology, reduction in wound area and hydroxyproline contents indicated that there was significant difference ( p <0.05) between group V and other groups. Quantitative histological studies and mean rank of the qualitative studies demonstrated that there was significant difference ( p <0.05) between group V and other groups. The Aloe vera with chitosan nanoparticle thin-film membranes had a reproducible wound healing potential and hereby justified its use in practice.

Temporal retinal thinning and the diagnosis of Alport syndrome and Thin basement membrane nephropathy.

PubMed

Chen, Yan; Colville, Deb; Ierino, Francesco; Symons, Andrew; Savige, Judy

2018-04-01

Alport syndrome is an inherited disease characterized by renal failure, hearing loss, and ocular abnormalities, including temporal retinal thinning. This study compared retinal thinning in Alport syndrome and other renal diseases. Alport syndrome was diagnosed on renal biopsy and genetic testing. Subjects underwent optical coherence tomography (OCT) (Spectralis OCT, Heidelberg Instruments). Retinal thinning was determined from horizontal macular OCT scans through the foveal center using the formula: Temporal thickness index (TTI) = (nasal - temporal thickness) ÷ nasal thickness × 100%, and compared with the normal range for each age group. Statistical analysis was performed using Student's t test, Mann-Whitney U test, and ROC analysis (SPPS, IBM). The mean temporal retinal thickness index was 12.4 ± 5.2% in men (n = 19) and 7.4 ± 1.4% in women (n = 28) with X-linked Alport syndrome; 13.1 ± 4.5% (n = 4) in recessive disease; 6.4 ± 2.2% (n = 5) in Thin basement membrane nephropathy; and 6.3 ± 3.3% (n = 14) in other renal diseases. Thinning was worse in men than women with X-linked disease (p < 0.01), and worse in men who developed early onset renal failure (R 2  = 0.75). Temporal retinal thinning was 84% sensitive for men with X-linked Alport syndrome and 67% specific (AUC = 0.83) compared with other renal diseases. Retinal temporal thinning is diagnostic for X-linked Alport syndrome in men and distinguishes them this condition from Thin basement membrane nephropathy, but only in men (p = 0.002). Temporal retinal thinning may also identify men and women with the rarer autosomal recessive disease.

Competitive concurrence of surface wrinkling and dewetting of liquid crystalline polymer films on non-wettable substrates.

PubMed

Song, Sung E; Choi, Gwan H; Yi, Gi-Ra; Yoo, Pil J

2017-11-01

Polymeric thin films coated on non-wettable substrates undergo film-instabilities, which are usually manifested as surface deformation in the form of dewetting or wrinkling. The former takes place in fluidic films, whereas the latter occurs in solid films. Therefore, there have rarely been reports of systems involving simultaneous deformations of dewetting and wrinkling. In this study, we propose polymeric thin films of liquid crystalline (LC) mesogens prepared on a non-wettable Si substrate and apply a treatment of plasma irradiation to form a thin polymerized layer at the surface. The resulting compressive stress generated in the surface region drives the formation of wrinkles, while at the same time, dipolar attraction between LC molecules induces competitive cohesive dewetting. Intriguing surface structures were obtained whereby dewetting-like hole arrays are nested inside the randomly propagated wrinkles. The structural features are readily controlled by the degree of surface cross-linking, hydrophilicity of the substrates, and the LC film thickness. In particular, dewetting of LC mesogens is observed to be restricted to occur at the trough regions of wrinkles, exhibiting the typical behavior of geometrically confined dewetting. Finally, wrinkling-dewetting mixed structures are separated from the substrate in the form of free standing films to demonstrate the potential applicability as membranes.

Absorbing TiOx thin film enabling laser welding of polyurethane membranes and polyamide fibers

PubMed Central

Amberg, Martin; Haag, Alexander; Storchenegger, Raphael; Rupper, Patrick; Lehmeier, Frederike; Rossi, René M; Hegemann, Dirk

2015-01-01

We report on the optical properties of thin titanium suboxide (TiOx) films for applications in laser transmission welding of polymers. Non-absorbing fibers were coated with TiOx coatings by reactive magnetron sputtering. Plasma process parameters influencing the chemical composition and morphology of the deposited thin films were investigated in order to optimize their absorption properties. Optical absorption spectroscopy showed that the oxygen content of the TiOx coatings is the main parameter influencing the optical absorbance. Overtreatment (high power plasma input) of the fiber surface leads to high surface roughness and loss of mechanical stability of the fiber. The study shows that thin substoichiometric TiOx films enable the welding of very thin polyurethane membranes and polyamide fibers with improved adhesion properties. PMID:27877837

Absorbing TiOx thin film enabling laser welding of polyurethane membranes and polyamide fibers

NASA Astrophysics Data System (ADS)

Amberg, Martin; Haag, Alexander; Storchenegger, Raphael; Rupper, Patrick; Lehmeier, Frederike; Rossi, René M.; Hegemann, Dirk

2015-10-01

We report on the optical properties of thin titanium suboxide (TiOx) films for applications in laser transmission welding of polymers. Non-absorbing fibers were coated with TiOx coatings by reactive magnetron sputtering. Plasma process parameters influencing the chemical composition and morphology of the deposited thin films were investigated in order to optimize their absorption properties. Optical absorption spectroscopy showed that the oxygen content of the TiOx coatings is the main parameter influencing the optical absorbance. Overtreatment (high power plasma input) of the fiber surface leads to high surface roughness and loss of mechanical stability of the fiber. The study shows that thin substoichiometric TiOx films enable the welding of very thin polyurethane membranes and polyamide fibers with improved adhesion properties.

Absorbing TiO x thin film enabling laser welding of polyurethane membranes and polyamide fibers.

PubMed

Amberg, Martin; Haag, Alexander; Storchenegger, Raphael; Rupper, Patrick; Lehmeier, Frederike; Rossi, René M; Hegemann, Dirk

2015-10-01

We report on the optical properties of thin titanium suboxide (TiO x ) films for applications in laser transmission welding of polymers. Non-absorbing fibers were coated with TiO x coatings by reactive magnetron sputtering. Plasma process parameters influencing the chemical composition and morphology of the deposited thin films were investigated in order to optimize their absorption properties. Optical absorption spectroscopy showed that the oxygen content of the TiO x coatings is the main parameter influencing the optical absorbance. Overtreatment (high power plasma input) of the fiber surface leads to high surface roughness and loss of mechanical stability of the fiber. The study shows that thin substoichiometric TiO x films enable the welding of very thin polyurethane membranes and polyamide fibers with improved adhesion properties.

Detergent Optimized Membrane Protein Reconstitution in Liposomes for Solid State NMR

PubMed Central

2015-01-01

For small helical membrane proteins, their structures are highly sensitive to their environment, and solid state NMR is a structural technique that can characterize these membrane proteins in native-like lipid bilayers and proteoliposomes. To date, a systematic method by which to evaluate the effect of the solubilizing detergent on proteoliposome preparations for solid state NMR of membrane proteins has not been presented in the literature. A set of experiments are presented aimed at determining the conditions most amenable to dialysis mediated reconstitution sample preparation. A membrane protein from M. tuberculosis is used to illustrate the method. The results show that a detergent that stabilizes the most protein is not always ideal and sometimes cannot be removed by dialysis. By focusing on the lipid and protein binding properties of the detergent, proteoliposome preparations can be readily produced, which provide double the signal-to-noise ratios for both the oriented sample and magic angle spinning solid state NMR. The method will allow more membrane protein drug targets to be structurally characterized in lipid bilayer environments. PMID:24665863

Dynamic behavior of ultra large graphene-based membranes using electrothermal transduction

NASA Astrophysics Data System (ADS)

Al-mashaal, A. K.; Wood, G. S.; Torin, A.; Mastropaolo, E.; Newton, M. J.; Cheung, R.

2017-12-01

This letter reports an experimental study of an electrothermal actuator made from an ultra-large graphene-based bilayer thin film with a diameter to thickness aspect ratio of ˜10 000. Suspended thin films consisting of multilayer graphene and 350-500 nm-thick Poly(methyl methacrylate) have been transferred over circular cavities with a diameter of 3.5 mm. The use of bilayer materials with different mechanical and thermal properties results in thin film structures that can be induced to vibrate mechanically under the electrothermal transduction mechanism. The dynamic response of the bilayer has been investigated electrothermally by driving the structures with a combination of alternating current and direct current actuation voltages ( Va c and Vd c) and characterizing their resonant frequencies. It has been found that the bilayer thin film structure behaves as a membrane. In addition, the actuation configurations affect not only the amplitude of vibration but also the tuning of the resonant frequency of the vibrating membranes. The existence of Joule heating-induced tension lowers the mechanical stiffness of the membrane and hence shifts the resonant frequency downwards by -108187 ppm. A resonant frequency of 3.26 kHz with a vibration amplitude of 4.34 nm has been achieved for 350 nm-thick membranes under actuation voltages of 1 V of Va c and 8 V of Vd c.

Microstructural Control and Characterization of Bi2V0.9Cu0.1O5.35 (BICUVOX) Ceramics

NASA Astrophysics Data System (ADS)

Razmyar, Soheil

2011-12-01

The widespread commercialization of solid-oxide fuel cells (SOFCs) and solid-oxide electrolyte cells (SOECs) is primarily limited by material degradation issues related to the required high temperature operation (>800°C). Applications of stabilized zirconia based electrolytes, which are the most commonly used oxide ion conductors, have been limited to this high temperature regime due to its low oxygen ion conductivity below 800°C. Solid electrolytes made of the BIMEVOX compositional family of materials (Bi2MexV 1-xO5.5-delta where Me=Cu, Co, Mg, Ni, Fe...) exhibit high oxide ionic conductivity similar to YSZ at a low temperature (300--600°C). Among these materials copper-substituted bismuth vanadate (Bi2V0.9Cu0.1O5.35, BICUVOX), was reported to have the highest ionic conductivity at 400°C (0.02 S/cm). It's one of the most important drawbacks of using BICUVOX, as a SOFC electrolyte is the low mechanical strength, which makes it unusable for most electrolyte supported applications. This research aims at improving mechanical strength by careful control of synthesis processing and sintering processes, thus making BICUVOX a viable material option for intermediate temperature SOFC. A co-precipitation method was used to synthesize submicron BICUVOX powder. The powder was utilized to fabricate a thin (< 250 microm) BICUVOX electrolyte membrane, with 2.5 cm2 active area and high mechanical strength. The fabricated BICUVOX membranes were densified to 97% theoretical density at lower sintering temperature and shorter time (675°C/1 h), and shows fine grain size (<1.5microm) and high mechanical strength (159 MPa).

High resolution transmission electron microscope Imaging and first-principles simulations of atomic-scale features in graphene membrane

NASA Astrophysics Data System (ADS)

Wang, Wei; Bhandari, Sagar; Yi, Wei; Bell, David; Westervelt, Robert; Kaxiras, Efthimios

2012-02-01

Ultra-thin membranes such as graphene[1] are of great importance for basic science and technology applications. Graphene sets the ultimate limit of thinness, demonstrating that a free-standing single atomic layer not only exists but can be extremely stable and strong [2--4]. However, both theory [5, 6] and experiments [3, 7] suggest that the existence of graphene relies on intrinsic ripples that suppress the long-wavelength thermal fluctuations which otherwise spontaneously destroy long range order in a two dimensional system. Here we show direct imaging of the atomic features in graphene including the ripples resolved using monochromatic aberration-corrected transmission electron microscopy (TEM). We compare the images observed in TEM with simulated images based on an accurate first-principles total potential. We show that these atomic scale features can be mapped through accurate first-principles simulations into high resolution TEM contrast. [1] Geim, A. K. & Novoselov, K. S. Nat. Mater. 6, 183-191, (2007). [2] Novoselov, K. S.et al. Science 306, 666-669, (2004). [3] Meyer, J. C. et al. Nature 446, 60-63, (2007). [4] Lee, C., Wei, X. D., Kysar, J. W. & Hone, J. Science 321, 385-388, (2008). [5] Nelson, D. R. & Peliti, L. J Phys-Paris 48, 1085-1092, (1987). [6] Fasolino, A., Los, J. H. & Katsnelson, M. I. Nat. Mater. 6, 858-861, (2007). [7] Meyer, J. C. et al. Solid State Commun. 143, 101-109, (2007).

The Ion Permeability Induced in Thin Lipid Membranes by the Polyene Antibiotics Nystatin and Amphotericin B

PubMed Central

Cass, Albert; Finkelstein, Alan; Krespi, Vivian

1970-01-01

Characteristics of nystatin and amphotericin B action on thin (<100 A) lipid membranes are: (a) micromolar amounts increase membrane conductance from 10-8 to over 10-2 Ω-1 cm-2; (b) such membranes are (non-ideally) anion selective and discriminate among anions on the basis of size; (c) membrane sterol is required for action; (d) antibiotic presence on both sides of membrane strongly favors action; (e) conductance is proportional to a large power of antibiotic concentration; (f) conductance decreases ∼104 times for a 10°C temperature rise; (g) kinetics of antibiotic action are also very temperature sensitive; (h) ion selectivity is pH independent between 3 and 10, but (i) activity is reversibly lost at high pH; (j) methyl ester derivatives are fully active; N-acetyl and N-succinyl derivatives are inactive; (k) current-voltage characteristic is nonlinear when membrane separates nonidentical salt solutions. These characteristics are contrasted with those of valinomycin. Observations (a)–(g) suggest that aggregates of polyene and sterol from opposite sides of the membrane interact to create aqueous pores; these pores are not static, but break up (melt) and reform continuously. Mechanism of anion selectivity is obscure. Observations (h)–(j) suggest—NH3 + is important for activity; it is probably not responsible for selectivity, particularly since four polyene antibiotics, each containing two—NH3 + groups, induce ideal cation selectivity. Possibly the many hydroxyl groups in nystatin and amphotericin B are responsible for anion selectivity. The effects of polyene antibiotics on thin lipid membranes are consistent with their action on biological membranes. PMID:5514157

Plasma surface modification of nanofiltration (NF) thin-film composite (TFC) membranes to improve anti organic fouling

NASA Astrophysics Data System (ADS)

Kim, Eun-Sik; Yu, Qingsong; Deng, Baolin

2011-09-01

Commercial nanofiltration (NF) thin-film composite (TFC) membranes were treated by low-pressure NH3 plasma, and the effects of the plasma treatment were investigated in terms of the membrane hydrophilicity, pure water flux, salt rejection, protein adsorption, and humic acid fouling. Experimental results indicated that the membrane surface hydrophilicity was increased by the plasma treatment, and changes in the hydrophilicity as well as membrane performance including permeate flux and fouling varied with the original membrane characteristics (e.g., roughness and hydrophilicity). Water flux of plasma treated membranes was the highest with 10 min and 90 W of plasma treatment, and salt rejection was mainly affected by the intensity of the plasma power. Results of bovine serum albumin (BSA) adsorption demonstrated that the protein adsorption decreased with increasing plasma treatment time. The plasma treatment that resulted in more negatively charged surfaces could also better prevent Aldrich humic acid (AHA) attachment on the membrane surface.

The production of ultrathin polyimide films for the solar sail program and Large Space Structures Technology (LSST): A feasibility study

NASA Technical Reports Server (NTRS)

Forester, R. H.

1978-01-01

Polyimide membranes of a thickness range from under 0.01 micron m to greater than 1 micron m can be produced at an estimated cost of 50 cents per sq m (plus the cost of the polymer). The polymer of interest is dissolved in a solvent which is solube in water. The polymer or casting solution is allowed to flow down an inclined ramp onto a water surface where a pool of floating polymer develops. The solvent dissolves into the water lowering the surface tension of the water on equently, the contact angle of the polymer pool is very low and the edge of the pool is very thin. The solvent dissolves from this thin region too rapidly to be replenished from the bulk of the pool and a solid polymer film forms. Firm formation is rapid and spontaneous and the film spreads out unaided, many feet from the leading edge of the pool. The driving force for this process is the exothermic solution of the organic solvent from the polymer solution into the water.

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

Hanc, Emil; Zając, Wojciech, E-mail: wojciech.zajac@agh.edu.pl; Lu, Li

Ceramic oxides exhibiting high lithium-ion mobility at room temperature receive broad attention as candidate electrolytes for lithium batteries. Lithium-stuffed garnets from the Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} group seem to be especially promising because of their high ionic conductivity at room temperature and their electrochemical stability. In this work, we discuss factors that affect formation of the garnet in its bulk form or in the form of thick and thin films. We demonstrate that zinc oxide can be applied as a sintering aid that facilitate the formation of the highly conducting cubic Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} garnet phase inmore » a single-step sintering procedure. Based on our experience with the single-step sintering experiments, we successfully fabricated a thick-film membrane consisting of a garnet solid electrolyte using the tape casting technique. In order to reduce the thickness of the electrolyte even further we investigated the fabrication of a thin-film Li{sub 7}La{sub 3}Zr{sub 2}O{sub 12} electrolyte by means of the pulsed laser deposition technique.« less

On fabrication procedures of Li-ion conducting garnets

NASA Astrophysics Data System (ADS)

Hanc, Emil; Zając, Wojciech; Lu, Li; Yan, Binggong; Kotobuki, Masashi; Ziąbka, Magdalena; Molenda, Janina

2017-04-01

Ceramic oxides exhibiting high lithium-ion mobility at room temperature receive broad attention as candidate electrolytes for lithium batteries. Lithium-stuffed garnets from the Li7La3Zr2O12 group seem to be especially promising because of their high ionic conductivity at room temperature and their electrochemical stability. In this work, we discuss factors that affect formation of the garnet in its bulk form or in the form of thick and thin films. We demonstrate that zinc oxide can be applied as a sintering aid that facilitate the formation of the highly conducting cubic Li7La3Zr2O12 garnet phase in a single-step sintering procedure. Based on our experience with the single-step sintering experiments, we successfully fabricated a thick-film membrane consisting of a garnet solid electrolyte using the tape casting technique. In order to reduce the thickness of the electrolyte even further we investigated the fabrication of a thin-film Li7La3Zr2O12 electrolyte by means of the pulsed laser deposition technique.

Structural characterization of the voltage sensor domain and voltage-gated K+- channel proteins vectorially-oriented within a single bilayer membrane at the solid/vapor and solid/liquid interfaces via neutron interferometry

PubMed Central

Gupta, S.; Dura, J.A.; Freites, J.A.; Tobias, D.J.; Blasie, J. K.

2012-01-01

The voltage-sensor domain (VSD) is a modular 4-helix bundle component that confers voltage sensitivity to voltage-gated cation channels in biological membranes. Despite extensive biophysical studies and the recent availability of x-ray crystal structures for a few voltage-gated potassium (Kv-) channels and a voltage-gate sodium (Nav-) channel, a complete understanding of the cooperative mechanism of electromechanical coupling, interconverting the closed-to-open states (i.e. non-conducting to cation conducting) remains undetermined. Moreover, the function of these domains is highly dependent on the physical-chemical properties of the surrounding lipid membrane environment. The basis for this work was provided by a recent structural study of the VSD from a prokaryotic Kv-channel vectorially-oriented within a single phospholipid (POPC; 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) membrane investigated by x-ray interferometry at the solid/moist He (or solid/vapor) and solid/liquid interfaces thus achieving partial to full hydration, respectively (Gupta et. al. Phys. Rev E. 2011, 84). Here, we utilize neutron interferometry to characterize this system in substantially greater structural detail at the sub-molecular level, due to its inherent advantages arising from solvent contrast variation coupled with the deuteration of selected sub-molecular membrane components, especially important for the membrane at the solid/liquid interface. We demonstrate the unique vectorial orientation of the VSD and the retention of its molecular conformation manifest in the asymmetric profile structure of the protein within the profile structure of this single bilayer membrane system. We definitively characterize the asymmetric phospholipid bilayer solvating the lateral surfaces of the VSD protein within the membrane. The profile structures of both the VSD protein and phospholipid bilayer depend upon the hydration state of the membrane. We also determine the distribution of water and exchangeable hydrogen throughout the profile structure of both the VSD itself and the VSD:POPC membrane. These two experimentally-determined water and exchangeable hydrogen distribution profiles are in good agreement with molecular dynamics simulations of the VSD protein vectorially-oriented within a fully hydrated POPC bilayer membrane, supporting the existence of the VSD’s water pore. This approach was extended to the full-length Kv-channel (KvAP) at solid/liquid interface, providing the separate profile structures of the KvAP protein and the POPC bilayer within the reconstituted KvAP:POPC membrane. PMID:22686684

Designable ultra-smooth ultra-thin solid-electrolyte interphases of three alkali metal anodes.

PubMed

Gu, Yu; Wang, Wei-Wei; Li, Yi-Juan; Wu, Qi-Hui; Tang, Shuai; Yan, Jia-Wei; Zheng, Ming-Sen; Wu, De-Yin; Fan, Chun-Hai; Hu, Wei-Qiang; Chen, Zhao-Bin; Fang, Yuan; Zhang, Qing-Hong; Dong, Quan-Feng; Mao, Bing-Wei

2018-04-09

Dendrite growth of alkali metal anodes limited their lifetime for charge/discharge cycling. Here, we report near-perfect anodes of lithium, sodium, and potassium metals achieved by electrochemical polishing, which removes microscopic defects and creates ultra-smooth ultra-thin solid-electrolyte interphase layers at metal surfaces for providing a homogeneous environment. Precise characterizations by AFM force probing with corroborative in-depth XPS profile analysis reveal that the ultra-smooth ultra-thin solid-electrolyte interphase can be designed to have alternating inorganic-rich and organic-rich/mixed multi-layered structure, which offers mechanical property of coupled rigidity and elasticity. The polished metal anodes exhibit significantly enhanced cycling stability, specifically the lithium anodes can cycle for over 200 times at a real current density of 2 mA cm -2 with 100% depth of discharge. Our work illustrates that an ultra-smooth ultra-thin solid-electrolyte interphase may be robust enough to suppress dendrite growth and thus serve as an initial layer for further improved protection of alkali metal anodes.

Difficulties in differentiating thin basement membrane disease from Alport syndrome.

PubMed

Żurawski, Jakub; Burchardt, Paweł; Seget, Monika; Moczko, Jerzy; Woźniak, Aldona; Grochowalski, Marcin; Salwa-Żurawska, Wiesława

We examined a group of 83 patients (57 children and 26 adults) with thin basement membrane disease and 17 patients with Alport syndrome. We compared the clinical data and, above all, the morphological patterns of both disease entities, with particular focus on not very advanced changes which might lead to a misdiagnosis due to the non-detection of the early stages of Alport syndrome.

Method of preparing water purification membranes. [polymerization of allyl amine as thin films in plasma discharge

NASA Technical Reports Server (NTRS)

Hollahan, J. R.; Wydeven, T. J., Jr. (Inventor)

1974-01-01

Allyl amine and chemically related compounds are polymerized as thin films in the presence of a plasma discharge. The monomer compound can be polymerized by itself or in the presence of an additive gas to promote polymerization and act as a carrier. The polymerized films thus produced show outstanding advantages when used as reverse osmosis membranes.

The anti-cancer peptide, PNC-27, induces tumor cell necrosis of a poorly differentiated non-solid tissue human leukemia cell line that depends on expression of HDM-2 in the plasma membrane of these cells.

PubMed

Davitt, Katlin; Babcock, Blake D; Fenelus, Maly; Poon, Chi Kong; Sarkar, Abhishek; Trivigno, Vincent; Zolkind, Paul A; Matthew, Sheena M; Grin'kina, Natalia; Orynbayeva, Zulfiya; Shaikh, Mohammad F; Adler, Victor; Michl, Josef; Sarafraz-Yazdi, Ehsan; Pincus, Matthew R; Bowne, Wilbur B

2014-01-01

We have developed the anti-cancer peptide, PNC-27, which is a membrane-active peptide that binds to the HDM-2 protein expressed in the cancer cell membranes of solid tissue tumor cells and induces transmembrane pore formation in cancer, but not in normal cells, resulting in tumor cell necrosis that is independent of p53 activity in these cells. We now extend our study to non-solid tissue tumor cells, in this case, a primitive, possible stem cell human leukemia cell line (K562) that is also p53-homozygously deleted. Our purpose was twofold: to investigate if these cells likewise express HDM-2 in their plasma membranes and to determine if our anti-cancer peptide induces tumor cell necrosis in these non-solid tissue tumor cells in a manner that depends on the interaction between the peptide and membrane-bound HDM-2. The anti-cancer activity and mechanism of PNC-27, which carries a p53 aa12-26-leader sequence connected on its carboxyl terminal end to a trans-membrane-penetrating sequence or membrane residency peptide (MRP), was studied against p53-null K562 leukemia cells. Murine leukocytes were used as a non-cancer cell control. Necrosis was determined by measuring the lactate dehydrogenase (LDH) release and apoptosis was determined by the detection of Caspases 3 and 7. Membrane colocalization of PNC-27 with HDM-2 was analyzed microscopically using fluorescently labeled antibodies against HDM-2 and PNC-27 peptides. We found that K562 cells strongly express HDM-2 protein in their membranes and that PNC-27 co-localizes with this protein in the membranes of these cells. PNC-27, but not the negative control peptide PNC-29, is selectively cytotoxic to K562 cells, inducing nearly 100 percent cell killing with LDH release. In contrast, this peptide had no effect on the lymphocyte control cells. The results suggest that HDM-2 is expressed in the membranes of non-solid tissue tumor cells in addition to the membranes of solid tissue tumor cells. Since K-562 cells appear to be in the stem cell family, the results suggest that early developing tumor cells also express HDM-2 protein in their membranes. Since PNC-27 induces necrosis of K-562 leukemia cells and co-localizes with HDM-2 in the tumor cell membrane as an early event, we conclude that the association of PNC-27 with HDM-2 in the cancer cell membrane results in trans-membrane pore formation which results in cancer cell death, as previously discovered in a number of different solid tissue tumor cells. Since K562 cells lack p53 expression, these effects of PNC-27 on this leukemia cell line occur by a p53-independent pathway. © 2014 by the Association of Clinical Scientists, Inc.

Effect of dope solution temperature on the membrane structure and membrane distillation performance

NASA Astrophysics Data System (ADS)

Nawi, N. I. M.; Bilad, M. R.; Nordin, N. A. H. M.

2018-04-01

Membrane distillation (MD) is a non-isothermal process applicable to purify water using hydrophobic membrane. Membrane in MD is hydrophobic, permeable to water vapor but repels liquid water. MD membrane is expected to pose high flux, high fouling and scaling resistances and most importantly high wetting resistance. This study develops flat-sheet polyvinylidene fluoride (PVDF) membrane by exploring both liquid-liquid and liquid-solid phase inversion technique largely to improve its wetting resistance and flux performance. We hypothesize that temperature of dope solution play roles in solid-liquid separation during membrane formation and an optimum balance between liquid-liquid and liquid-solid (crystallization) separation leads to highly performance PVDF membrane. Findings obtained from differential scanning calorimeter test show that increasing dope solution temperature reduces degree of PVDF crystallinity and suppresses formation of crystalline structure. The morphological images of the resulting membranes show that at elevated dope solution temperature (40, 60, 80 and 100°C), the spherulite-like structures are formed across the thickness of membranes ascribed from due to different type of crystals. The performance of direct-contact MD shows that the obtained flux of the optimum dope temperature (60°C) of 10.8 L/m2h is comparable to commercial PTFE-based MD membrane.

Structure and dynamics of cationic membrane peptides and proteins: Insights from solid-state NMR

PubMed Central

Hong, Mei; Su, Yongchao

2011-01-01

Many membrane peptides and protein domains contain functionally important cationic Arg and Lys residues, whose insertion into the hydrophobic interior of the lipid bilayer encounters significant energy barriers. To understand how these cationic molecules overcome the free energy barrier to insert into the lipid membrane, we have used solid-state NMR spectroscopy to determine the membrane-bound topology of these peptides. A versatile array of solid-state NMR experiments now readily yields the conformation, dynamics, orientation, depth of insertion, and site-specific protein–lipid interactions of these molecules. We summarize key findings of several Arg-rich membrane peptides, including β-sheet antimicrobial peptides, unstructured cell-penetrating peptides, and the voltage-sensing helix of voltage-gated potassium channels. Our results indicate the central role of guanidinium-phosphate and guanidinium-water interactions in dictating the structural topology of these cationic molecules in the lipid membrane, which in turn account for the mechanisms of this functionally diverse class of membrane peptides. PMID:21344534

Composite membranes from photochemical synthesis of ultrathin polymer films

NASA Astrophysics Data System (ADS)

Liu, Chao; Martin, Charles R.

1991-07-01

THERE has recently been a resurgence of interest in synthetic membranes and membrane-based processes1-12. This is motivated by a wide variety of technological applications, such as chemical separations1-7, bioreactors and sensors8,9, energy conversion10,11 and drug-delivery systems12. Many of these technologies require the ability to prepare extremely thin, defect-free synthetic (generally polymeric) films, which are supported on microporous supports to form composite membranes. Here we describe a method for producing composite membranes of this sort that incorporate high-quality polymer films less than 50-nm thick. The method involves interfacial photopolymerization of a thin polymer film on the surface of the microporous substrate. We have been able to use this technique to synthesize a variety of functionalized ultrathin films based on electroactive, photoactive and ion-exchange polymers. We demonstrate the method here with composite membranes that show exceptional gas-transport properties.

Pentachlorophenol removal from water using surfactant-enhanced filtration through low-pressure thin film composite membranes.

PubMed

Kumar, Yogesh; Popat, K M; Brahmbhatt, H; Ganguly, B; Bhattacharya, A

2008-06-15

Removal of pentachlorophenol from water is investigated using the surfactant-enhanced cross-flow membrane filtration technique in which anionic surfactant; sodium dodecyl sulfate (SDS) is the carrier of pentachlorophenol. The separation performances are studied by varying SDS concentrations (

Functionality in Electrospun Nanofibrous Membranes Based on Fiber's Size, Surface Area, and Molecular Orientation

PubMed Central

Matsumoto, Hidetoshi; Tanioka, Akihiko

2011-01-01

Electrospinning is a versatile method for forming continuous thin fibers based on an electrohydrodynamic process. This method has the following advantages: (i) the ability to produce thin fibers with diameters in the micrometer and nanometer ranges; (ii) one-step forming of the two- or three-dimensional nanofiber network assemblies (nanofibrous membranes); and (iii) applicability for a broad spectrum of molecules, such as synthetic and biological polymers and polymerless sol-gel systems. Electrospun nanofibrous membranes have received significant attention in terms of their practical applications. The major advantages of nanofibers or nanofibrous membranes are the functionalities based on their nanoscaled-size, highly specific surface area, and highly molecular orientation. These functionalities of the nanofibrous membranes can be controlled by their fiber diameter, surface chemistry and topology, and internal structure of the nanofibers. This report focuses on our studies and describes fundamental aspects and applications of electrospun nanofibrous membranes. PMID:24957735

Composite solid polymer electrolyte membranes

DOEpatents

Formato, Richard M.; Kovar, Robert F.; Osenar, Paul; Landrau, Nelson; Rubin, Leslie S.

2001-06-19

The present invention relates to composite solid polymer electrolyte membranes (SPEMs) which include a porous polymer substrate interpenetrated with an ion-conducting material. SPEMs of the present invention are useful in electrochemical applications, including fuel cells and electrodialysis.

Composite solid polymer electrolyte membranes

DOEpatents

Formato, Richard M.; Kovar, Robert F.; Osenar, Paul; Landrau, Nelson; Rubin, Leslie S.

2006-05-30

The present invention relates to composite solid polymer electrolyte membranes (SPEMs) which include a porous polymer substrate interpenetrated with an ion-conducting material. SPEMs of the present invention are useful in electrochemical applications, including fuel cells and electrodialysis.

Non-woven PET fabric reinforced and enhanced the performance of ultrafiltration membranes composed of PVDF blended with PVDF-g-PEGMA for industrial applications

NASA Astrophysics Data System (ADS)

Wang, Shuai; Li, Tong; Chen, Chen; Chen, Sheng; Liu, Baicang; Crittenden, John

2018-03-01

Ultrafiltration (UF) membranes composed of poly(vinylidene fluoride) (PVDF) blended with poly(vinylidene fluoride)-graft-poly(ethylene glycol) methyl ether methacrylate (PVDF-g-PEGMA) can present high flux and excellent foulant removal efficiencies under suitable preparation conditions. However, these PVDF/PVDF-g-PEGMA blended membranes cannot be applied industrially because of the insufficient mechanical strength (strength-to-break value of 8.4 ± 0.6 MPa). We incorporated two types of non-woven polyethylene terephthalate (PET) fabrics (thin hydrophobic and thick hydrophilic fabrics) as support layers to improve the mechanical properties of the blended membranes. The thin and thick PET fabrics were able to significantly improve the tensile strength to 23.3 ± 3.7 MPa and 30.1 ± 1.4 MPa, respectively. The PET fabrics had a limited impact on the separation-related membrane performance such as hydrophilicity, foulant rejection, whereas the mechanical strength and pure water flux was improved several folds. The enhanced flux was attributed to the higher surface porosity and wider finger-like voids in the cross-section. The thin PET fabric with larger porosity was able to maintain a consistent toughness simultaneously; thus it is recommended as a support material for this blended membrane.

A stochastic model of solid state thin film deposition: Application to chalcopyrite growth

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

Lovelett, Robert J.; Pang, Xueqi; Roberts, Tyler M.

Developing high fidelity quantitative models of solid state reaction systems can be challenging, especially in deposition systems where, in addition to the multiple competing processes occurring simultaneously, the solid interacts with its atmosphere. In this work, we develop a model for the growth of a thin solid film where species from the atmosphere adsorb, diffuse, and react with the film. The model is mesoscale and describes an entire film with thickness on the order of microns. Because it is stochastic, the model allows us to examine inhomogeneities and agglomerations that would be impossible to characterize with deterministic methods. We demonstratemore » the modeling approach with the example of chalcopyrite Cu(InGa)(SeS){sub 2} thin film growth via precursor reaction, which is a common industrial method for fabricating thin film photovoltaic modules. The model is used to understand how and why through-film variation in the composition of Cu(InGa)(SeS){sub 2} thin films arises and persists. We believe that the model will be valuable as an effective quantitative description of many other materials systems used in semiconductors, energy storage, and other fast-growing industries.« less

A stochastic model of solid state thin film deposition: Application to chalcopyrite growth

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

Lovelett, Robert J.; Pang, Xueqi; Roberts, Tyler M.

Developing high fidelity quantitative models of solid state reaction systems can be challenging, especially in deposition systems where, in addition to the multiple competing processes occurring simultaneously, the solid interacts with its atmosphere. Here, we develop a model for the growth of a thin solid film where species from the atmosphere adsorb, diffuse, and react with the film. The model is mesoscale and describes an entire film with thickness on the order of microns. Because it is stochastic, the model allows us to examine inhomogeneities and agglomerations that would be impossible to characterize with deterministic methods. We also demonstrate themore » modeling approach with the example of chalcopyrite Cu(InGa)(SeS) 2 thin film growth via precursor reaction, which is a common industrial method for fabricating thin film photovoltaic modules. The model is used to understand how and why through-film variation in the composition of Cu(InGa)(SeS) 2 thin films arises and persists. Finally, we believe that the model will be valuable as an effective quantitative description of many other materials systems used in semiconductors, energy storage, and other fast-growing industries.« less

A stochastic model of solid state thin film deposition: Application to chalcopyrite growth

DOE PAGES

Lovelett, Robert J.; Pang, Xueqi; Roberts, Tyler M.; ...

2016-04-01

Developing high fidelity quantitative models of solid state reaction systems can be challenging, especially in deposition systems where, in addition to the multiple competing processes occurring simultaneously, the solid interacts with its atmosphere. Here, we develop a model for the growth of a thin solid film where species from the atmosphere adsorb, diffuse, and react with the film. The model is mesoscale and describes an entire film with thickness on the order of microns. Because it is stochastic, the model allows us to examine inhomogeneities and agglomerations that would be impossible to characterize with deterministic methods. We also demonstrate themore » modeling approach with the example of chalcopyrite Cu(InGa)(SeS) 2 thin film growth via precursor reaction, which is a common industrial method for fabricating thin film photovoltaic modules. The model is used to understand how and why through-film variation in the composition of Cu(InGa)(SeS) 2 thin films arises and persists. Finally, we believe that the model will be valuable as an effective quantitative description of many other materials systems used in semiconductors, energy storage, and other fast-growing industries.« less

Self-Mixing Thin-Slice Solid-State Laser Metrology

PubMed Central

Otsuka, Kenju

2011-01-01

This paper reviews the dynamic effect of thin-slice solid-state lasers subjected to frequency-shifted optical feedback, which led to the discovery of the self-mixing modulation effect, and its applications to quantum-noise-limited versatile laser metrology systems with extreme optical sensitivity. PMID:22319406

Surface engineering: molecularly imprinted affinity membranes by photograft polymerization

NASA Astrophysics Data System (ADS)

Matuschewski, Heike; Sergeyeva, Tatiana A.; Bendig, Juergen; Piletsky, Sergey A.; Ulbricht, Matthies; Schedler, Uwe

2001-02-01

Commercial polymer microfiltration membranes were surface-modified with a graft copolymer of a functional monomer and a crosslinker in the presence of a template (triazine-herbicide). As result, membranes covered with a thin layer of imprinted polymer (MIP) selective to the template were obtained. The influence of the polymerization conditions on membrane recognition properties was studied by membranes

Laser ablation for membrane processing of AlGaN/GaN- and micro structured ferroelectric thin film MEMS and SiC pressure sensors for extreme conditions

NASA Astrophysics Data System (ADS)

Zehetner, J.; Vanko, G.; Dzuba, J.; Ryger, I.; Lalinsky, T.; Benkler, Manuel; Lucki, Michal

2015-05-01

AlGaN/GaN based high electron mobility transistors (HEMTs), Schottky diodes and/or resistors have been presented as sensing devices for mechanical or chemical sensors operating in extreme conditions. In addition we investigate ferroelectric thin films for integration into micro-electro-mechanical-systems (MEMS). Creation of appropriate diaphragms and/or cantilevers out of SiC is necessary for further improvement of sensing properties of such MEMS sensors. For example sensitivity of the AlGaN/GaN based MEMS pressure sensor can be modified by membrane thickness. We demonstrated that a 4H-SiC 80μm thick diaphragms can be fabricated much faster with laser ablation than by electrochemical, photochemical or reactive ion etching (RIE). We were able to verify the feasibility of this process by fabrication of micromechanical membrane structures also in bulk 3C-SiC, borosilicate glass, sapphire and Al2O3 ceramic substrates by femtosecond laser (520nm) ablation. On a 350μm thick 4H-SiC substrate we produced an array of 275μm deep and 1000μm to 3000μm of diameter blind holes without damaging the 2μm AlN layer at the back side. In addition we investigated ferroelectric thin films as they can be deposited and micro-patterned by a direct UV-lithography method after the ablation process for a specific membrane design. The risk to harm or damage the function of thin films was eliminated by that means. Some defects in the ablated membranes are also affected by the polarisation of the laser light. Ripple structures oriented perpendicular to the laser polarisation promote creation of pin holes which would perforate a thin membrane. We developed an ablation technique strongly inhibiting formation of ripples and pin poles.

Thin-Film Nanocomposite Membrane with the Minimum Amount of MOF by the Langmuir-Schaefer Technique for Nanofiltration.

PubMed

Navarro, Marta; Benito, Javier; Paseta, Lorena; Gascón, Ignacio; Coronas, Joaquín; Téllez, Carlos

2018-01-10

An innovative procedure for positioning a monolayer of hydrophilic metal organic framework (MOF) MIL-101(Cr) (MIL, Materials of Institute Lavoisier) nanoparticles (NPs) in thin-film nanocomposite (TFN) membranes has been implemented by transferring a Langmuir-Schaefer (LS) film of the MOF in between the polyamide thin layer at the top and the cross-linked asymmetric polyimide (P84) support at the bottom. The presence and layout of the LS-MIL-101(Cr) monolayer in the TFN membrane was confirmed by scanning transmission electron microscopy imaging with a high-angle annular dark-field detector images and X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, electron energy loss spectroscopy, and atomic force microscopy analyses. This methodology requires the smallest amount of MOF reported to date, 3.8 μg cm -2 , and promotes the formation of a defect-free ultrathin MOF film. Although conventional TFN membranes tend to show MOF agglomerates that could contribute to the formation of unselective defects, LS-TFN membranes, characterized by a homogeneous and continuous MOF coating, exhibit an optimal membrane performance, without a significant decrease in selectivity. Outstanding methanol permeances, one of the best results reported to date, of 10.1 ± 0.5 L m -2 h -1 bar -1 when filtering sunset yellow and of 9.5 ± 2.1 L m -2 h -1 bar -1 when filtering rose bengal have been achieved in LS-TFN membranes with a rejection higher than 90% in all cases. Methanol permeates through the polyamide and the LS-MIL-101(Cr) monolayer, greatly enhanced by the MOF pore system, in comparison to thin-film composite and conventional TFN membranes (7.5 ± 0.7 and 7.7 ± 1.1 L m -2 h -1 bar -1 when filtering sunset yellow), respectively, in which polyamide areas free of MOF NPs are present.

SSM-based electrophysiology.

PubMed

Schulz, Patrick; Garcia-Celma, Juan J; Fendler, Klaus

2008-10-01

An assay technique for the electrical characterization of electrogenic transport proteins on solid supported membranes is presented. Membrane vesicles, proteoliposomes or membrane fragments containing the transporter are adsorbed to the solid supported membrane and are activated by providing a substrate or a ligand via a rapid solution exchange. This technique opens up new possibilities where conventional electrophysiology fails like transporters or ion channels from bacteria and from intracellular compartments. Its rugged design and potential for automation make it suitable for drug screening.

Surface plasmon resonance spectroscopy studies of membrane proteins: transducin binding and activation by rhodopsin monitored in thin membrane films.

PubMed Central

Salamon, Z; Wang, Y; Soulages, J L; Brown, M F; Tollin, G

1996-01-01

Surface plasmon resonance (SPR) spectroscopy can provide useful information regarding average structural properties of membrane films supported on planar solid substrates. Here we have used SPR spectroscopy for the first time to monitor the binding and activation of G-protein (transducin or Gt) by bovine rhodopsin incorporated into an egg phosphatidylcholine bilayer deposited on a silver film. Rhodopsin incorporation into the membrane, performed by dilution of a detergent solution of the protein, proceeds in a saturable manner. Before photolysis, the SPR data show that Gt binds tightly (Keq approximately equal to 60 nM) and with positive cooperativity to rhodopsin in the lipid layer to form a closely packed film. A simple multilayer model yields a calculated average thickness of about 57 A, in good agreement with the structure of Gt. The data also demonstrate that Gt binding saturates at a Gt/rhodopsin ratio of approximately 0.6. Moreover, upon visible light irradiation, characteristic changes occur in the SPR spectrum, which can be modeled by a 6 A increase in the average thickness of the lipid/protein film caused by formation of metarhodopsin II (MII). Upon subsequent addition of GTP, further SPR spectral changes are induced. These are interpreted as resulting from dissociation of the alpha-subunit of Gt, formation of new MII-Gt complexes, and possible conformational changes of Gt as a consequence of complex formation. The above results clearly demonstrate the ability of SPR spectroscopy to monitor interactions among the proteins associated with signal transduction in membrane-bound systems. Images FIGURE 1 PMID:8804611

Numerical study of the influence of solid polarization on electrophoresis at finite Debye thickness.

PubMed

Bhattacharyya, Somnath; De, Simanta

2015-09-01

The influence of solid polarization on the electrophoresis of a uniformly charged dielectric particle for finite values of the particle-to-fluid dielectric permittivity ratio is analyzed quantitatively without imposing the thin Debye length or weak-field assumption. Present analysis is based on the computation of the coupled Poisson-Nernst-Planck and Stokes equations in the fluid domain along with the Laplace equation within the solid. The electrophoretic velocity is determined through the balance of forces acting on the particle. The solid polarization of the charged particle produces a reduction on its electrophoretic velocity compared to a nonpolarizable particle of the same surface charge density. In accordance with the existing thin-layer analysis, our computed results for thin Debye layer shows that the solid polarization is important only when the applied electric field is strong. When the Debye length is in the order of the particle size, the electrophoretic velocity decreases with the rise of the particle permittivity and attains a saturation limit at large values of the permittivity. Our computed solution for electrophoretic velocity is in agreement with the existing asymptotic analyses based on a thin Debye layer for limiting cases.

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

DOEpatents

Liu, Wei

2014-05-06

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

Instabilities and diffusion in a hydrodynamic model of a fluid membrane coupled to a thin active fluid layer.

PubMed

Sarkar, N; Basu, A

2012-11-01

We construct a coarse-grained effective two-dimensional (2d hydrodynamic theory as a theoretical model for a coupled system of a fluid membrane and a thin layer of a polar active fluid in its ordered state that is anchored to the membrane. We show that such a system is prone to generic instabilities through the interplay of nonequilibrium drive, polar order and membrane fluctuation. We use our model equations to calculate diffusion coefficients of an inclusion in the membrane and show that their values depend strongly on the system size, in contrast to their equilibrium values. Our work extends the work of S. Sankararaman and S. Ramaswamy (Phys. Rev. Lett., 102, 118107 (2009)) to a coupled system of a fluid membrane and an ordered active fluid layer. Our model is broadly inspired by and should be useful as a starting point for theoretical descriptions of the coupled dynamics of a cell membrane and a cortical actin layer anchored to it.

Manufacturing polymer thin films in a micro-gravity environment

NASA Technical Reports Server (NTRS)

Vera, Ivan

1987-01-01

This project represents Venezuela's first scientific experiment in space. The apparatus for the automatic casting of two polymer thin films will be contained in NASA's Payload No. G-559 of the Get Away Special program for a future orbital space flight in the U.S. Space Shuttle. Semi-permeable polymer membranes have important applications in a variety of fields, such as medicine, energy, and pharmaceuticals and in general fluid separation processes, such as reverse osmosis, ultrafiltration, and electrodialysis. The casting of semi-permeable membranes in space will help to identify the roles of convection in determining the structure of these membranes.

Capabilities of ICP-RIE cryogenic dry etching of silicon: review of exemplary microstructures

NASA Astrophysics Data System (ADS)

Sökmen, Ü.; Stranz, A.; Fündling, S.; Wehmann, H.-H.; Bandalo, V.; Bora, A.; Tornow, M.; Waag, A.; Peiner, E.

2009-10-01

Inductively coupled plasma (ICP) cryogenic dry etching was used to etch submicron pores, nano contact lines, submicron diameter pillars, thin and thick cantilevers, membrane structures and anisotropic deep structures with high aspect ratios in silicon for bio-nanoelectronics, optoelectronics and nano-micro electromechanical systems (NMEMS). The ICP cryogenic dry etching gives us the advantage of switching plasmas between etch rates of 13 nm min-1 and 4 µm min-1 for submicron pores and for membrane structures, respectively. A very thin photoresist mask can endure at -75 °C even during etching 70 µm deep for cantilevers and 300 µm deep for membrane structures. Coating the backsides of silicon membrane substrates with a thin photoresist film inhibited the lateral etching of cantilevers during their front release. Between -95 °C and -140 °C, we realized crystallographic-plane-dependent etching that creates facets only at the etch profile bottom. By varying the oxygen content and the process temperature, we achieved good control over the shape of the etched structures. The formation of black silicon during membrane etching down to 300 µm was delayed by reducing the oxygen content.

A Study on Anti – Fouling Behaviour and Mechanical Properties of PVA/Chitosan/TEOS Hybrid membrane in The Treatment of Copper Solution

NASA Astrophysics Data System (ADS)

Sulaiman, N. A.; Kassim Shaari, N. Z.; Rahman, N. Abdul

2018-05-01

In a wastewater treatment by using membrane filtration, fouling has been one of the major problems. In this study, the anti-fouling behaviour of the fabricated thin-film composite membrane were studied during the treatment of water containing copper ion. The membranes were prepared from a polymer blend of 2wt.% chitosan with 10 wt.% poly(vinyl alcohol) (PVA) and then it was cross – linked with tetraethylorthosilicate (TEOS) through sol-gel method. The membrane had been evaluated for its resistance against organic fouling where humic acid had been chosen as organic foulant model which represent the natural organic matter (NOM) in water or wastewater. The dead-end filtration experiments were carried out by using 50 ppm of copper solution with and without the presence of humic acid as feed solution, which was passed through two types of thin film composite membranes. The possible reversible fouling was evaluated by using relative flux decay (RFD) and relative flux recovery (RFR) calculations. The percentage of copper ion removal was evaluated by using Atomic Absorption Spectroscopy (AAS). Based on the results, with the presence of humic acid, the membrane incorporated with silica precursor (TEOS) showed lower flux decay (3%) and higher flux recovery (76%), which show that the formulated hybrid membrane possesses the anti fouling property. The same trend was observed in the mechanical properties of hybrid membrane, where the presence of TEOS has improved the tensile strength and flexibility of the membrane. Therefore, the fabricated thin film composite with the anti-fouling properties and good physical flexibility has potential to be used in the treatment of wastewater containing heavy metal as it could result in good saving in term of operational cost.

Thin Film Solid Lubricant Development

NASA Technical Reports Server (NTRS)

Benoy, Patricia A.

1997-01-01

Tribological coatings for high temperature sliding applications are addressed. A sputter-deposited bilayer coating of gold and chromium is investigated as a potential solid lubricant for protection of alumina substrates during sliding at high temperature. Evaluation of the tribological properties of alumina pins sliding against thin sputtered gold films on alumina substrates is presented.

Rechargeable thin film battery and method for making the same

DOEpatents

Goldner, Ronald B.; Liu, Te-Yang; Goldner, Mark A.; Gerouki, Alexandra; Haas, Terry E.

2006-01-03

A rechargeable, stackable, thin film, solid-state lithium electrochemical cell, thin film lithium battery and method for making the same is disclosed. The cell and battery provide for a variety configurations, voltage and current capacities. An innovative low temperature ion beam assisted deposition method for fabricating thin film, solid-state anodes, cathodes and electrolytes is disclosed wherein a source of energetic ions and evaporants combine to form thin film cell components having preferred crystallinity, structure and orientation. The disclosed batteries are particularly useful as power sources for portable electronic devices and electric vehicle applications where high energy density, high reversible charge capacity, high discharge current and long battery lifetimes are required.

Effects of Aloe Vera and Chitosan Nanoparticle Thin-Film Membranes on Wound Healing in Full Thickness Infected Wounds with Methicillin Resistant Staphylococcus Aureus

PubMed Central

Ranjbar, Reza; Yousefi, Alireza

2018-01-01

Objective : To assess effect of Aleo vera with chitosan nanoparticle biofilm on wound healing in full thickness infected wounds with antibiotic resistant gram positive bacteria. Method: Thirty rats were randomized into five groups of six rats each. Group I: Animals with uninfected wounds treated with 0.9% saline solution. Group II: Animals with infected wounds treated with saline. Group III: Animals with infected wounds were dressed with chitosan nanoparticle thin-film membranes. Group IV: Animals with infected wounds were treated topically with Aloe vera and Group V: Animals with infected wounds were treated topically with Aloe vera and dressed with chitosan nanoparticle thin-film membranes. Wound size was measured on 6, 9, 12, 15, 18 and 21days after surgery. Results: Microbiology, reduction in wound area and hydroxyproline contents indicated that there was significant difference (p<0.05) between group V and other groups. Quantitative histological studies and mean rank of the qualitative studies demonstrated that there was significant difference (p<0.05) between group V and other groups. Conclusion: The Aloe vera with chitosan nanoparticle thin-film membranes had a reproducible wound healing potential and hereby justified its use in practice. PMID:29379804

Fundamental transport mechanisms, fabrication and potential applications of nanoporous atomically thin membranes.

PubMed

Wang, Luda; Boutilier, Michael S H; Kidambi, Piran R; Jang, Doojoon; Hadjiconstantinou, Nicolas G; Karnik, Rohit

2017-06-06

Graphene and other two-dimensional materials offer a new approach to controlling mass transport at the nanoscale. These materials can sustain nanoscale pores in their rigid lattices and due to their minimum possible material thickness, high mechanical strength and chemical robustness, they could be used to address persistent challenges in membrane separations. Here we discuss theoretical and experimental developments in the emerging field of nanoporous atomically thin membranes, focusing on the fundamental mechanisms of gas- and liquid-phase transport, membrane fabrication techniques and advances towards practical application. We highlight potential functional characteristics of the membranes and discuss applications where they are expected to offer advantages. Finally, we outline the major scientific questions and technological challenges that need to be addressed to bridge the gap from theoretical simulations and proof-of-concept experiments to real-world applications.

Increase in membrane thickness during development compensates for eggshell thinning due to calcium uptake by the embryo in falcons

NASA Astrophysics Data System (ADS)

Castilla, Aurora M.; van Dongen, Stefan; Herrel, Anthony; Francesch, Amadeu; Martínez de Aragón, Juan; Malone, Jim; José Negro, Juan

2010-02-01

We compared membrane thickness of fully developed eggs with those of non-developed eggs in different endangered falcon taxa. To our knowledge, membrane thickness variation during development has never been examined before in falcons or any other wild bird. Yet, the egg membrane constitutes an important protective barrier for the developing embryo. Because eggshell thinning is a general process that occurs during bird development, caused by calcium uptake by the embryo, eggs are expected to be less protected and vulnerable to breakage near the end of development. Thus, egg membranes could play an important protective role in the later stages of development by getting relatively thicker. We used linear mixed models to explore the variation in membrane thickness ( n = 378 eggs) in relation to developmental stage, taxon, female age, mass and identity (73 females), egg-laying sequence (105 clutches) and the study zone. Our results are consistent with the prediction that egg membranes are thicker in fully developed eggs than in non-developed eggs, suggesting that the increase in membrane thickness during development may compensate for eggshell thinning. In addition, our data shown that thicker membranes are associated with larger, heavier and relatively wider eggs, as well as with eggs that had thinner eggshells. Egg-laying sequence, female age and the study zone did not explain the observed variation of membrane thickness in the falcon taxa studied. As we provide quantitative data on membrane thickness variation during development in falcons not subjected to contamination or food limitation (i.e. bred under captive conditions), our data may be used as a reference for studies on eggs from natural populations. Considering the large variation in membrane thickness and the multiple factors affecting on it and its importance in the protection of the embryo, we encourage other researchers to include measurements on membranes in studies exploring eggshell thickness variation.

Antifouling Thin-Film Composite Membranes by Controlled Architecture of Zwitterionic Polymer Brush Layer.

PubMed

Liu, Caihong; Lee, Jongho; Ma, Jun; Elimelech, Menachem

2017-02-21

In this study, we demonstrate a highly antifouling thin-film composite (TFC) membrane by grafting a zwitterionic polymer brush via atom-transfer radical-polymerization (ATRP), a controlled, environmentally benign chemical process. Initiator molecules for polymerization were immobilized on the membrane surface by bioinspired catechol chemistry, leading to the grafting of a dense zwitterionic polymer brush layer. Surface characterization revealed that the modified membrane exhibits reduced surface roughness, enhanced hydrophilicity, and lower surface charge. Chemical force microscopy demonstrated that the modified membrane displayed foulant-membrane interaction forces that were 1 order of magnitude smaller than those of the pristine TFC membrane. The excellent fouling resistance imparted by the zwitterionic brush layer was further demonstrated by significantly reduced adsorption of proteins and bacteria. In addition, forward osmosis fouling experiments with a feed solution containing a mixture of organic foulants (bovine-serum albumin, alginate, and natural organic matter) indicated that the modified membrane exhibited significantly lower water flux decline compared to the pristine TFC membrane. The controlled architecture of the zwitterionic polymer brush via ATRP has the potential for a facile antifouling modification of a wide range of water treatment membranes without compromising intrinsic transport properties.

Orthogonal functionalization of nanoporous substrates: control of 3D surface functionality.

PubMed

Lazzara, Thomas D; Kliesch, Torben-Tobias; Janshoff, Andreas; Steinem, Claudia

2011-04-01

Anodic aluminum oxide (AAO) membranes with aligned, cylindrical, nonintersecting pores were selectively functionalized in order to create dual-functionality substrates with different pore-rim and pore-interior surface functionalities, using silane chemistry. We used a two-step process involving an evaporated thin gold film to protect the underlying surface functionality of the pore rims. Subsequent treatment with oxygen plasma of the modified AAO membrane removed the unprotected organic functional groups, i.e., the pore-interior surface. After gold removal, the substrate became optically transparent, and displayed two distinct surface functionalities, one at the pore-rim surface and another at the pore-interior surface. We achieved a selective hydrophobic functionalization with dodecyl-trichlorosilane of either the pore rims or the pore interiors. The deposition of planar lipid membranes on the functionalized areas by addition of small unilamellar vesicles occurred in a predetermined fashion. Small unilamellar vesicles only ruptured upon contact with the hydrophobic substrate regions forming solid supported hybrid bilayers. In addition, pore-rim functionalization with dodecyl-trichlorosilane allowed the formation of pore-spanning hybrid lipid membranes as a result of giant unilamellar vesicle rupture. Confocal laser scanning microscopy was employed to identify the selective spatial localization of the adsorbed fluorescently labeled lipids. The corresponding increase in the AAO refractive index due to lipid adsorption on the hydrophobic regions was monitored by optical waveguide spectroscopy. This simple orthogonal functionalization route is a promising method to control the three-dimensional surface functionality of nanoporous films. © 2011 American Chemical Society

Triclosan-immobilized polyamide thin film composite membranes with enhanced biofouling resistance

NASA Astrophysics Data System (ADS)

Park, Sang-Hee; Hwang, Seon Oh; Kim, Taek-Seung; Cho, Arah; Kwon, Soon Jin; Kim, Kyoung Taek; Park, Hee-Deung; Lee, Jung-Hyun

2018-06-01

We report on a strategy to improve biofouling resistance of a polyamide (PA) thin-film composite (TFC) reverse osmosis (RO) membrane via chemically immobilizing triclosan (TC), known as a common organic biocide, on its surface. To facilitate covalent attachment of TC on the membrane surface, TC was functionalized with amine moiety to prepare aminopropyl TC. Then, the TC-immobilized TFC (TFC-TC) membranes were fabricated through a one-step amide formation reaction between amine groups of aminopropyl TC and acyl chloride groups present on the PA membrane surface, which was confirmed by high-resolution XPS. Strong stability of the immobilized TC was also confirmed by a hydraulic washing test. Although the TFC-TC membrane showed slightly reduced separation performance compared to the pristine control, it still maintained a satisfactory RO performance level. Importantly, the TFC-TC membrane exhibited excellent antibacterial activity against both gram negative (E. coli and P. aeruginosa) and gram positive (S. aureus) bacteria along with greatly enhanced resistance to biofilm formation. Our immobilization approach offers a robust and relatively benign strategy to control biofouling of functional surfaces, films and membranes.

Structure and Membrane Interactions of the Antibiotic Peptide Dermadistinctin K by Multidimensional Solution and Oriented 15N and 31P Solid-State NMR Spectroscopy

PubMed Central

Verly, Rodrigo M.; Moraes, Cléria Mendonça de; Resende, Jarbas M.; Aisenbrey, Christopher; Bemquerer, Marcelo Porto; Piló-Veloso, Dorila; Valente, Ana Paula; Almeida, Fábio C.L.; Bechinger, Burkhard

2009-01-01

DD K, a peptide first isolated from the skin secretion of the Phyllomedusa distincta frog, has been prepared by solid-phase chemical peptide synthesis and its conformation was studied in trifluoroethanol/water as well as in the presence of sodium dodecyl sulfate and dodecylphosphocholine micelles or small unilamellar vesicles. Multidimensional solution NMR spectroscopy indicates an α-helical conformation in membrane environments starting at residue 7 and extending to the C-terminal carboxyamide. Furthermore, DD K has been labeled with 15N at a single alanine position that is located within the helical core region of the sequence. When reconstituted into oriented phosphatidylcholine membranes the resulting 15N solid-state NMR spectrum shows a well-defined helix alignment parallel to the membrane surface in excellent agreement with the amphipathic character of DD K. Proton-decoupled 31P solid-state NMR spectroscopy indicates that the peptide creates a high level of disorder at the level of the phospholipid headgroup suggesting that DD K partitions into the bilayer where it severely disrupts membrane packing. PMID:19289046

Solid-state membrane module

DOEpatents

Hinklin, Thomas Ray; Lewinsohn, Charles Arthur

2015-06-30

A module for separating oxygen from an oxygen-containing gaseous mixture comprising planar solid-state membrane units, each membrane unit comprising planar dense mixed conducting oxides layers, planar channel-free porous support layers, and one or more planar intermediate support layers comprising at least one channeled porous support layer. The porosity of the planar channeled porous support layers is less than the porosity of the planar channel-free porous support layers.

Solid-state lithium battery

DOEpatents

Ihlefeld, Jon; Clem, Paul G; Edney, Cynthia; Ingersoll, David; Nagasubramanian, Ganesan; Fenton, Kyle Ross

2014-11-04

The present invention is directed to a higher power, thin film lithium-ion electrolyte on a metallic substrate, enabling mass-produced solid-state lithium batteries. High-temperature thermodynamic equilibrium processing enables co-firing of oxides and base metals, providing a means to integrate the crystalline, lithium-stable, fast lithium-ion conductor lanthanum lithium tantalate (La.sub.1/3-xLi.sub.3xTaO.sub.3) directly with a thin metal foil current collector appropriate for a lithium-free solid-state battery.

Membrane-entrapped microperoxidase as a 'solid-state' promoter in the electrochemistry of soluble metalloproteins.

PubMed Central

Brunori, M; Santucci, R; Campanella, L; Tranchida, G

1989-01-01

Immobilization of biological systems in solid matrices is presently of great interest, in view of the many potential advantages associated with both the higher stability of the immobilized macromolecules and the potential utilization for biotechnology. In the present paper the electrochemical behaviour of the undecapeptide from cytochrome c (called microperoxidase) tightly entrapped in cellulose triacetate membrane is reported; its utilization as 'solid-state' promoter in the electrochemistry of soluble metalloproteins is presented. The results obtained indicate that: (i) membrane-entrapped microperoxidase undergoes rapid reversible electron transfer at a glassy carbon electrode; (ii) the electrochemical process is diffusion-controlled; (iii) entrapped microperoxidase acts as 'solid-state' promoter in the electrochemistry of soluble cytochrome c and of azurin. PMID:2557833

Development of an ultra-thin film comprised of a graphene membrane and carbon nanotube vein support.

PubMed

Lin, Xiaoyang; Liu, Peng; Wei, Yang; Li, Qunqing; Wang, Jiaping; Wu, Yang; Feng, Chen; Zhang, Lina; Fan, Shoushan; Jiang, Kaili

2013-01-01

Graphene, exhibiting superior mechanical, thermal, optical and electronic properties, has attracted great interest. Considering it being one-atom-thick, and the reduced mechanical strength at grain boundaries, the fabrication of large-area suspended chemical vapour deposition graphene remains a challenge. Here we report the fabrication of an ultra-thin free-standing carbon nanotube/graphene hybrid film, inspired by the vein-membrane structure found in nature. Such a square-centimetre-sized hybrid film can realize the overlaying of large-area single-layer chemical vapour deposition graphene on to a porous vein-like carbon nanotube network. The vein-membrane-like hybrid film, with graphene suspended on the carbon nanotube meshes, possesses excellent mechanical performance, optical transparency and good electrical conductivity. The ultra-thin hybrid film features an electron transparency close to 90%, which makes it an ideal gate electrode in vacuum electronics and a high-performance sample support in transmission electron microscopy.

Integration of biological method and membrane technology in treating palm oil mill effluent.

PubMed

Zhang, Yejian; Yan, Li; Qiao, Xiangli; Chi, Lina; Niu, Xiangjun; Mei, Zhijian; Zhang, Zhenjia

2008-01-01

Palm oil industry is the most important agro-industry in Malaysia, but its by-product-palm oil mill effluent (POME), posed a great threat to water environment. In the past decades, several treatment and disposal methods have been proposed and investigated to solve this problem. A two-stage pilot-scale plant was designed and constructed for POME treatment. Anaerobic digestion and aerobic biodegradation constituted the first biological stage, while ultrafiltration (UF) and reverse osmosis (RO) membrane units were combined as the second membrane separation stage. In the anaerobic expanded granular sludge bed (EGSB) reactor, about 43% organic matter in POME was converted into biogas, and COD reduction efficiency reached 93% and 22% in EGSB and the following aerobic reactor, respectively. With the treatment in the first biological stage, suspended solids and oil also decreased to a low degree. All these alleviated the membrane fouling and prolonged the membrane life. In the membrane process unit, almost all the suspended solids were captured by UF membranes, while RO membrane excluded most of the dissolved solids or inorganic salts from RO permeate. After the whole treatment processes, organic matter in POME expressed by BOD and COD was removed almost thoroughly. Suspended solids and color were not detectable in RO permeate any more, and mineral elements only existed in trace amount (except for K and Na). The high-quality effluent was crystal clear and could be used as the boiler feed water.

Preparation and Characterization of Chitosan Thin Films on Mixed-Matrix Membranes for Complete Removal of Chromium.

PubMed

Nayak, Vignesh; Jyothi, Mannekote Shivanna; Balakrishna, R Geetha; Padaki, Mahesh; Ismail, Ahmad Fauzi

2015-06-01

Herein we present a new approach for the complete removal of Cr(VI) species, through reduction of Cr(VI) to Cr(III), followed by adsorption of Cr(III). Reduction of chromium from water is an important challenge, as Cr(IV) is one of the most toxic substances emitted from industrial processes. Chitosan (CS) thin films were developed on plain polysulfone (PSf) and PSf/TiO2 membrane substrates by a temperature-induced technique using polyvinyl alcohol as a binder. Structure property elucidation was carried out by X-ray diffraction, microscopy, spectroscopy, contact angle measurement, and water uptake studies. The increase in hydrophilicity followed the order: PSf < PSf/TiO2 < PSf/TiO2/CS membranes. Use of this thin-film composite membrane for chromium removal was investigated with regards to the effects of light and pH. The observations reveal 100 % reduction of Cr(VI) to Cr(III) through electrons and protons donated from OH and NH2 groups of the CS layer; the reduced Cr(III) species are adsorbed onto the CS layer via complexation to give chromium-free water.

Electrolyte-Sensing Transistor Decals Enabled by Ultrathin Microbial Nanocellulose

PubMed Central

Yuen, Jonathan D.; Walper, Scott A.; Melde, Brian J.; Daniele, Michael A.; Stenger, David A.

2017-01-01

We report an ultra-thin electronic decal that can simultaneously collect, transmit and interrogate a bio-fluid. The described technology effectively integrates a thin-film organic electrochemical transistor (sensing component) with an ultrathin microbial nanocellulose wicking membrane (sample handling component). As far as we are aware, OECTs have not been integrated in thin, permeable membrane substrates for epidermal electronics. The design of the biocompatible decal allows for the physical isolation of the electronics from the human body while enabling efficient bio-fluid delivery to the transistor via vertical wicking. High currents and ON-OFF ratios were achieved, with sensitivity as low as 1 mg·L−1. PMID:28102316

Micromachined Thin-Film Sensors for SOI-CMOS Co-Integration

NASA Astrophysics Data System (ADS)

Laconte, Jean; Flandre, D.; Raskin, Jean-Pierre

Co-integration of sensors with their associated electronics on a single silicon chip may provide many significant benefits regarding performance, reliability, miniaturization and process simplicity without significantly increasing the total cost. Micromachined Thin-Film Sensors for SOI-CMOS Co-integration covers the challenges and interests and demonstrates the successful co-integration of gas flow sensors on dielectric membrane, with their associated electronics, in CMOS-SOI technology. We firstly investigate the extraction of residual stress in thin layers and in their stacking and the release, in post-processing, of a 1 μm-thick robust and flat dielectric multilayered membrane using Tetramethyl Ammonium Hydroxide (TMAH) silicon micromachining solution.

Electrolyte-Sensing Transistor Decals Enabled by Ultrathin Microbial Nanocellulose

NASA Astrophysics Data System (ADS)

Yuen, Jonathan D.; Walper, Scott A.; Melde, Brian J.; Daniele, Michael A.; Stenger, David A.

2017-01-01

We report an ultra-thin electronic decal that can simultaneously collect, transmit and interrogate a bio-fluid. The described technology effectively integrates a thin-film organic electrochemical transistor (sensing component) with an ultrathin microbial nanocellulose wicking membrane (sample handling component). As far as we are aware, OECTs have not been integrated in thin, permeable membrane substrates for epidermal electronics. The design of the biocompatible decal allows for the physical isolation of the electronics from the human body while enabling efficient bio-fluid delivery to the transistor via vertical wicking. High currents and ON-OFF ratios were achieved, with sensitivity as low as 1 mg·L-1.

Thin PDMS Films Using Long Spin Times or Tert-Butyl Alcohol as a Solvent

PubMed Central

Koschwanez, John H.; Carlson, Robert H.; Meldrum, Deirdre R.

2009-01-01

Thin polydimethylsiloxane (PDMS) films are frequently used in “lab on a chip” devices as flexible membranes. The common solvent used to dilute the PDMS for thin films is hexane, but hexane can swell the underlying PDMS substrate. A better solvent would be one that dissolves uncured PDMS but doesn't swell the underlying substrate. Here, we present protocols and spin curves for two alternatives to hexane dilution: longer spin times and dilution in tert-butyl alcohol. The thickness of the PDMS membranes under different spin speeds, spin times, and PDMS concentrations was measured using an optical profilometer. The use of tert-butyl alcohol to spin thin PDMS films does not swell the underlying PDMS substrate, and we have used these films to construct multilayer PDMS devices. PMID:19238212

Fabrication of high aspect ratio tungsten nanostructures on ultrathin c-Si membranes for extreme UV applications

NASA Astrophysics Data System (ADS)

Delachat, F.; Le Drogoff, B.; Constancias, C.; Delprat, S.; Gautier, E.; Chaker, M.; Margot, J.

2016-01-01

In this work, we demonstrate a full process for fabricating high aspect ratio diffraction optics for extreme ultraviolet lithography. The transmissive optics consists in nanometer scale tungsten patterns standing on flat, ultrathin (100 nm) and highly transparent (>85% at 13.5 nm) silicon membranes (diameter of 1 mm). These tungsten patterns were achieved using an innovative pseudo-Bosch etching process based on an inductively coupled plasma ignited in a mixture of SF6 and C4F8. Circular ultra-thin Si membranes were fabricated through a state-of-the-art method using direct-bonding with thermal difference. The silicon membranes were sputter-coated with a few hundred nanometers (100-300 nm) of stress-controlled tungsten and a very thin layer of chromium. Nanoscale features were written in a thin resist layer by electron beam lithography and transferred onto tungsten by plasma etching of both the chromium hard mask and the tungsten layer. This etching process results in highly anisotropic tungsten features at room temperature. The homogeneity and the aspect ratio of the advanced pattern transfer on the membranes were characterized with scanning electron microscopy after focus ion beam milling. An aspect ratio of about 6 for 35 nm size pattern is successfully obtained on a 1 mm diameter 100 nm thick Si membrane. The whole fabrication process is fully compatible with standard industrial semiconductor technology.

TOPICAL REVIEW: Ultra-thin film encapsulation processes for micro-electro-mechanical devices and systems

NASA Astrophysics Data System (ADS)

Stoldt, Conrad R.; Bright, Victor M.

2006-05-01

A range of physical properties can be achieved in micro-electro-mechanical systems (MEMS) through their encapsulation with solid-state, ultra-thin coatings. This paper reviews the application of single source chemical vapour deposition and atomic layer deposition (ALD) in the growth of submicron films on polycrystalline silicon microstructures for the improvement of microscale reliability and performance. In particular, microstructure encapsulation with silicon carbide, tungsten, alumina and alumina-zinc oxide alloy ultra-thin films is highlighted, and the mechanical, electrical, tribological and chemical impact of these overlayers is detailed. The potential use of solid-state, ultra-thin coatings in commercial microsystems is explored using radio frequency MEMS as a case study for the ALD alloy alumina-zinc oxide thin film.

Synthesis of thin film containing 4-amino-1,2,4-triazole iron(II) complexes

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

Onggo, Djulia, E-mail: djulia@Chem.itb.ac.id

The Iron(II) complex with 4-amino-1,2,4 triazole (NH{sub 2}-trz) ligand has potential applications as smart material since the compounds show a distinct color change from lilac at low temperature to colorless at high temperature. The lilac color of the complex represent the diamagnetic low spin state while the colorless correspond to the paramagnetic high spin state of iron(II). The transition between the two states could be tuned by changing the anionic group. Generally, the complex was synthesized directly from aqueous solution of iron(II) salt with considerable amounts of NH{sub 2}-trz solution produced solid powder compound. For application as an electronic molecularmore » device, the complex should be obtained as a thin film. The transparent [Fe(NH{sub 2}trz){sub 3}]-Nafion film has been successfully obtained, however, no anion variation can be produced since the nafion is an anionic resin. In this work, the [Fe(NH{sub 2}trz){sub 3}]-complexes with several anions have been synthesized inside nata de coco membrane that commonly used as a medium for deposition metal nano-particles. After drying the membrane containing the complex became a thin film. At room temperature, the film containing iron(II) complexes of sulphate and nitrate salts show lilac color, similar to that of the original complexes in the powder form. On heating, the color of the complex film changed to colorless and this color change was observed reversibly. In contrast, the films containing perchlorate and tetrafluoroborate iron(II) complexes are colorless at room temperature and changed to lilac on cooling. The significant color changing of the iron(II)complexes in the nata de coco film can be used for demonstration thermo chromic effect of smart materials with relatively small amount of the compounds.« less

Tidal dissipation in the subsurface ocean of Enceladus

NASA Astrophysics Data System (ADS)

Matsuyama, I.; Hay, H.; Nimmo, F.; Kamata, S.

2017-12-01

Icy satellites of the outer solar system have emerged as potential habitable worlds due to the presence of subsurface oceans. As a long-term energy source, tidal heating in these oceans can influence the survivability of subsurface oceans, and the thermal, rotational, and orbital evolution of these satellites. Additionally, the spatial and temporal variation of tidal heating has implications for the interior structure and spacecraft observations. Previous models for dissipation in thin oceans are not generally applicable to icy satellites because either they ignore the presence of an overlying solid shell or use a thin shell membrane approximation. We present a new theoretical treatment for tidal dissipation in thin oceans with overlying shells of arbitrary thickness and apply it to Enceladus. The shell's resistance to ocean tides increases with shell thickness, reducing tidal dissipation as expected. Both the magnitude of energy dissipation and the resonant ocean thicknesses decrease as the overlying shell thickness increases, as previously shown using a membrane approximation. In contrast to previous work based on the traditional definition of the tidal quality factor, Q, our new definition is consistent with higher energy dissipation for smaller Q, and introduces a lower limit on Q. The dissipated power and tides are not in phase with the forcing tidal potential due to the delayed ocean response. The phase lag depends on the Rayleigh friction coefficient and ocean and shell thicknesses, which implies that phase lag observations can be used to constrain these parameters. Eccentricity heating produces higher dissipation near the poles, while obliquity heating produces higher dissipation near the equator, in contrast to the dissipation patterns in the shell. The time-averaged surface distribution of tidal heating can generate lateral shell thickness variations, providing an additional constraint on the Rayleigh friction coefficient. Explaining the endogenic power radiated from the south polar terrain requires shell thicknesses smaller than about 1 km, a value that is not consistent with recent libration, gravity and topography constraints.

Ceramic membrane by tape casting and sol-gel coating for microfiltration and ultrafiltration application

NASA Astrophysics Data System (ADS)

Das, Nandini; Maiti, H. S.

2009-11-01

Alumina membrane filters in the form of thin (0.3-0.8 mm) discs of 25-30 mm diameter suitable for microfiltration application have been fabricated by tape-casting technique. Further using this microfiltration membrane as substrate, boehmite sol coating was applied on it and ultrafiltration membrane with very small thickness was formed. The pore size of the microfiltration membrane could be varied in the range of 0.1-0.7 μm through optimisation of experimental parameter. In addition, each membrane shows a very narrow pore size distribution. The most important factor, which determines the pore size of the membrane, is the initial particle size and its distribution of the ceramic powder. The top thin ultrafiltration, boehmite layer was prepared by sol-gel method, with a thickness of 0.5 μm. Particle size of the sol was approximately 30-40 nm. The structure and formation of the layer was analysed through TEM. At 550 °C formation of the top layer was completed. The pore size of the ultrafiltration membrane measured from TEM micrograph was almost 10 nm. Results of microbial (Escherichia coli—smallest-sized water-borne bacteria) test confirm the possibility of separation through this membrane

An Effective Design of Electrically Conducting Thin-Film Composite (TFC) Membranes for Bio and Organic Fouling Control in Forward Osmosis (FO).

PubMed

Liu, Qing; Qiu, Guanglei; Zhou, Zhengzhong; Li, Jingguo; Amy, Gary Lee; Xie, Jianping; Lee, Jim Yang

2016-10-04

The organic foulants and bacteria in secondary wastewater treatment can seriously impair the membrane performance in a water treatment plant. The embedded electrode approach using an externally applied potential to repel organic foulants and inhibit bacterial adhesion can effectively reduce the frequency of membrane replacement. Electrode embedment in membranes is often carried out by dispensing a conductor (e.g., carbon nanotubes, or CNTs) in the membrane substrate, which gives rise to two problems: the leaching-out of the conductor and a percolation-limited membrane conductivity that results in an added energy cost. This study presents a facile method for the embedment of a continuous electrode in thin-film composite (TFC) forward osmosis (FO) membranes. Specifically, a conducting porous carbon paper is used as the understructure for the formation of a membrane substrate by the classical phase inversion process. The carbon paper and the membrane substrate polymer form an interpenetrating structure with good stability and low electrical resistance (only about 1Ω/□). The membrane-electrode assembly was deployed as the cathode of an electrochemical cell, and showed good resistance to organic and microbial fouling with the imposition of a 2.0 V DC voltage. The carbon paper-based FO TFC membranes also possess good mechanical stability for practical use.

Improved separation and antifouling properties of thin-film composite nanofiltration membrane by the incorporation of cGO

NASA Astrophysics Data System (ADS)

Li, Hongbin; Shi, Wenying; Du, Qiyun; Zhou, Rong; Zhang, Haixia; Qin, Xiaohong

2017-06-01

Poly(piperazine amide) composite nanofiltration (NF) membranes were modified through the incorporation of carboxylated graphene oxide (cGO) in the polyamide layer during the interfacial polymerization (IP) process on the polysulfone (PSF)/nonwoven fabric (NWF) ultrafiltration (UF) substrate membrane surface. The composition and morphology of the prepared NF membrane surface were determined by means of ATR-FTIR, SEM-EDX and AFM. The effects of cGO contents on membrane hydrophilicity, separation performance and antifouling properties were investigated through Water Contact Angle (WCA) analysis, the permeance and three-cycle fouling measurements. The growth model of cGO-incorporated polyamide thin-film was proposed. Compared to the original NF membranes, the surface hydrophilicity, water permeability, salt rejection and antifouling properties of the cGO-incorporated NF membrane had all improved. When cGO content was 100 ppm, the MgSO4 rejection of composite NF membrane reached a maximum value of 99.2% meanwhile membrane obtained an obvious enhanced water flux (81.6 L m-2 h-1, at 0.7 MPa) which was nearly three times compared to the virginal NF membrane. The cGO-incorporated NF membrane showed an excellent selectivity of MgSO4 and NaCl with the rejection ratio of MgSO4/NaCl of approximately 8.0.

Hybrid Filter Membrane

NASA Technical Reports Server (NTRS)

Laicer, Castro; Rasimick, Brian; Green, Zachary

2012-01-01

Cabin environmental control is an important issue for a successful Moon mission. Due to the unique environment of the Moon, lunar dust control is one of the main problems that significantly diminishes the air quality inside spacecraft cabins. Therefore, this innovation was motivated by NASA s need to minimize the negative health impact that air-suspended lunar dust particles have on astronauts in spacecraft cabins. It is based on fabrication of a hybrid filter comprising nanofiber nonwoven layers coated on porous polymer membranes with uniform cylindrical pores. This design results in a high-efficiency gas particulate filter with low pressure drop and the ability to be easily regenerated to restore filtration performance. A hybrid filter was developed consisting of a porous membrane with uniform, micron-sized, cylindrical pore channels coated with a thin nanofiber layer. Compared to conventional filter media such as a high-efficiency particulate air (HEPA) filter, this filter is designed to provide high particle efficiency, low pressure drop, and the ability to be regenerated. These membranes have well-defined micron-sized pores and can be used independently as air filters with discreet particle size cut-off, or coated with nanofiber layers for filtration of ultrafine nanoscale particles. The filter consists of a thin design intended to facilitate filter regeneration by localized air pulsing. The two main features of this invention are the concept of combining a micro-engineered straight-pore membrane with nanofibers. The micro-engineered straight pore membrane can be prepared with extremely high precision. Because the resulting membrane pores are straight and not tortuous like those found in conventional filters, the pressure drop across the filter is significantly reduced. The nanofiber layer is applied as a very thin coating to enhance filtration efficiency for fine nanoscale particles. Additionally, the thin nanofiber coating is designed to promote capture of dust particles on the filter surface and to facilitate dust removal with pulse or back airflow.

Low Voltage MEMS Digital Loudspeaker Array Based on Thin-film PZT Actuators

NASA Astrophysics Data System (ADS)

Fanget, S.; Casset, F.; Dejaeger, R.; Maire, F.; Desloges, B.; Deutzer, J.; Morisson, R.; Bohard, Y.; Laroche, B.; Escato, J.; Leclere, Q.

This paper reports on the development of a Digital Loudspeaker Array (DLA) solution based on Pb(Zr0.52,Ti0.48)O3 (PZT) thin-film actuated membranes. These membranes called speaklets are arranged in a matrix and operate in a binary manner by emitting short pulses of sound pressure. Using the principle of additivity of pressures in the air, it is possible to reconstruct audible sounds. For the first time, electromechanical and acoustic characterizations are reported on a 256-MEMS-membranes DLA. Sounds audible as far as several meters from the loudspeaker have been generated using low voltage (8 V).

Suspended sub-50 nm vanadium dioxide membrane transistors: fabrication and ionic liquid gating studies

NASA Astrophysics Data System (ADS)

Sim, Jai S.; Zhou, You; Ramanathan, Shriram

2012-10-01

We demonstrate a robust lithographic patterning method to fabricate self-supported sub-50 nm VO2 membranes that undergo a phase transition. Utilizing such self-supported membranes, we directly observed a shift in the metal-insulator transition temperature arising from stress relaxation and consistent opening of the hysteresis. Electric double layer transistors were then fabricated with the membranes and compared to thin film devices. The ionic liquid allowed reversible modulation of channel resistance and distinguishing bulk processes from the surface effects. From the shift in the metal-insulator transition temperature, the carrier density doped through electrolyte gating is estimated to be 1 × 1020 cm-3. Hydrogen annealing studies showed little difference in resistivity between the film and the membrane indicating rapid diffusion of hydrogen in the vanadium oxide rutile lattice consistent with previous observations. The ability to fabricate electrically-wired, suspended VO2 ultra-thin membranes creates new opportunities to study mesoscopic size effects on phase transitions and may also be of interest in sensor devices.

Layer-by-Layer Assembly for Preparation of High-Performance Forward Osmosis Membrane

NASA Astrophysics Data System (ADS)

Yang, Libin; Zhang, Jinglong; Song, Peng; Wang, Zhan

2018-01-01

Forward osmosis (FO) membrane with high separation performance is needed to promote its practical applications. Herein, layer-by-layer (LbL) approach was used to prepare a thin and highly cross-linked polyamide layer on a polyacrylonitrile substrate surface to prepare a thin-film composite forward osmosis (TFC-FO) membrane with enhanced FO performance. The effects of monomer concentrations and assembly cycles on the performance of the TFC-FO membranes were systematically investigated. Under the optimal preparation condition, TFC-FO membrane achieved the best performance, exhibiting the water flux of 14.4/6.9 LMH and reverse salt flux of 7.7/3.8 gMH under the pressure retarded osmosis/forward osmosis (PRO/FO) mode using 1M NaCl as the draw against a DI-water feed, and a rejection of 96.1% for 2000 mg/L NaCl aqueous solution. The result indicated that layer-by-layer method was a potential method to regulate the structure and performance of the TFC-FO membrane.

Functional, photochemically active, and chemically asymmetric membranes by interfacial polymerization of derivatized multifunctional prepolymers

DOEpatents

Lonsdale, H.K.; Wamser, C.C.

1990-04-17

The preparation of a novel class of thin film membranes by interfacial polymerization is disclosed, said membranes incorporating as part of their polymeric structure the functionality of monomeric or oligomeric precursors. Specific embodiments include porphyrin and phthalocyanine derivatives that are photochemically or electrochemically active, as well as chemically asymmetric membranes.

Functional, photochemically active, and chemically asymmetric membranes by interfacial polymerization of derivatized multifunctional prepolymers

DOEpatents

Lonsdale, Harold K.; Wamser, Carl C.

1990-01-01

The preparation of a novel class of thin film membranes by interfacial polymerization is disclosed, said membranes incorporating as part of their polymeric structure the functionality of monomeric or oligomeric precursors. Specific embodiments include porphyrin and phthalocyanine derivatives that are photochemically or electrochemically active, as well as chemically asymmetric membranes.

Current status of solid-state lithium batteries employing solid redox polymerization cathodes

NASA Astrophysics Data System (ADS)

Visco, S. J.; Doeff, M. M.; Dejonghe, L. C.

1991-03-01

The rapidly growing demand for secondary batteries having high specific energy and power has naturally led to increased efforts in lithium battery technology. Still, the increased safety risks associated with high energy density systems has tempered the enthusiasm of proponents of such systems for use in the consumer marketplace. The inherent advantages of all-solid-state batteries in regards to safety and reliability are strong factors in advocating their introduction to the marketplace. However, the low ionic conductivity of solid electrolytes relative to nonaqueous liquid electrolytes implies low power densities for solid state systems operating at ambient temperatures. Recent advances in polymer electrolytes have led to the introduction of solid electrolytes having conductivities in the range of 10(exp -4)/ohm cm at room temperature; this is still two orders of magnitude lower than liquid electrolytes. Although these improved ambient conductivities put solid state batteries in the realm of practical devices, it is clear that solid state batteries using such polymeric separators will be thin film devices. Fortunately, thin film fabrication techniques are well established in the plastics and paper industry, and present the possibility of continuous web-form manufacturing. This style of battery manufacture should make solid polymer batteries very cost-competitive with conventional secondary cells. In addition, the greater geometric flexibility of thin film solid state cells should provide benefits in terms of the end-use form factor in device design. This work discusses the status of solid redox polymerization cathodes.

The effect of microgeometry, implant thickness and polyurethane chemistry on the foreign body response to subcutaneous implants.

PubMed

Ward, W Kenneth; Slobodzian, Emily P; Tiekotter, Kenneth L; Wood, Michael D

2002-11-01

We addressed the effect of implant thickness, implant porosity, and polyurethane (PU) chemistry on angiogenesis and on the foreign body response in rats. The following materials were implanted subcutaneously for 7 weeks then excised for histologic analysis: a solid PU; a solid polyurethane with silicone and polyethylene oxide (PU-S-PEO); porous expanded polytetrafluoroethylene (ePTFE); and porous polyvinyl alcohol sponge (PVA). Two thicknesses of PU-S-PEO were compared: 300 microns (thin) and 2000 microns (thick). Foreign body capsule (FBC) thickness was much less in PU-S-PEO implants than in PU implants. In addition, FBC were thinner in thin implants than in thick implants. FBC was much more dense in solid implants than in porous implants. As compared with solid implants, porous implants (PVA and ePTFE) led to a marked increase in the number of microvessels that developed adjacent to the implant, as observed both with hematoxylin/eosin staining and with an immunohistochemical anti-endothelial stain. We conclude that the polyethylene oxide and silicone moieties in PU reduce the thickness of the subsequent FBC. In addition, thin implants lead to a thin FBC. Porous implants (PVA and ePTFE) cause more angiogenesis than solid implants. These results may have implications for the measurement of blood-derived analytes by biosensors.

Dispersible Exfoliated Zeolite Nanosheets and Their Application as a Selective Membrane

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

Varoon, Kumar; Zhang, Xueyi; Elyassi, Bahman

2011-10-06

Thin zeolite films are attractive for a wide range of applications, including molecular sieve membranes, catalytic membrane reactors, permeation barriers, and low-dielectric-constant materials. Synthesis of thin zeolite films using high-aspect-ratio zeolite nanosheets is desirable because of the packing and processing advantages of the nanosheets over isotropic zeolite nanoparticles. Attempts to obtain a dispersed suspension of zeolite nanosheets via exfoliation of their lamellar precursors have been hampered because of their structure deterioration and morphological damage (fragmentation, curling, and aggregation). We demonstrated the synthesis and structure determination of highly crystalline nanosheets of zeolite frameworks MWW and MFI. The purity and morphological integritymore » of these nanosheets allow them to pack well on porous supports, facilitating the fabrication of molecular sieve membranes.« less

High-Precision Shape Control of In-Space Deployable Large Membrane/Thin-Shell Reflectors

NASA Technical Reports Server (NTRS)

Watkins, Ronald; Goebel, Dan; Hofer, Richard

2010-01-01

This innovation has been developed to improve the resolutions of future spacebased active and passive microwave antennas for earth-science remote sensing missions by maintaining surface figure precisions of large membrane/thin-shell reflectors during orbiting. The intention is for these sensing instruments to be deployable at orbit altitudes one or two orders of magnitude higher than Low Earth Orbit (LEO), but still being able to acquire measurements at spatial resolution and sensitivity similar to those of LEO. Because active and passive microwave remote sensors are able to penetrate through clouds to acquire vertical profile measurements of geophysical parameters, it is desirable to elevate them to the higher orbits to obtain orbital geometries that offer large spatial coverage and more frequent observations. This capability is essential for monitoring and for detailed understanding of the life cycles of natural hazards, such as hurricanes, tropical storms, flash floods, and tsunamis. Major components of this high-precision antenna-surface-control system include a membrane/thin shell reflector, a metrology sensor, a controller, actuators, and corresponding power amplifier and signal conditioning electronics (see figure). Actuators are attached to the back of the reflector to produce contraction/ expansion forces to adjust the shape of the thin-material reflector. The wavefront-sensing metrology system continuously measures the surface figure of the reflector, converts the surface figure to digital data and feeds the data to the controller. The controller determines the control parameters and generates commands to the actuator system. The flexible, piezoelectric polymer actuators are thus activated, providing the control forces needed to correct any distortions that exist in the reflector surface. Piezoelectric polymer actuators are very thin and flexible. They can be implemented on the back of the membrane/thin-shell reflector without introducing significant amounts of mass or stiffness to the reflector. They can be rolled up or folded to accommodate the packaging needed for launch. An analytical model of the system, which includes the membrane reflector, actuator, and controller has been developed to investigate the functionality of this control system on a 35-meter-diameter membrane reflector. The performance of this system under external disturbances such as in space thermal loads and W-error due to inflation has been investigated. A subscale breadboard has been developed, and the functionality of this control concept has been demonstrated by this breadboard.

Preparation and Properties of New Inorganic Glasses and Gel-Derived Solids

DTIC Science & Technology

1991-04-01

route were examined, including the use of SiC and diamond powder as fillers and some triphasic , solids. Many ferroelectnic thin films were prepared...use of SiC and diamond powder as fillers and some triphasic solids. Many ferroelectric thin films were prepared and their properties measured. An...Exit Filter Mmrn Holder Filter He Gas Perforated Pyrolysis Reactor 00 0 00 00 00 00 0 0 0 0 Soutolution asWe Fi.8.Shmai darm fepeiena0yses I I I ci

Parametric study of thin film evaporation from nanoporous membranes

NASA Astrophysics Data System (ADS)

Wilke, Kyle L.; Barabadi, Banafsheh; Lu, Zhengmao; Zhang, TieJun; Wang, Evelyn N.

2017-10-01

The performance and lifetime of advanced electronics are often dictated by the ability to dissipate heat generated within the device. Thin film evaporation from nanoporous membranes is a promising thermal management approach, which reduces the thermal transport distance across the liquid film while also providing passive capillary pumping of liquid to the evaporating interface. In this work, we investigated the dependence of thin film evaporation from nanoporous membranes on a variety of geometric parameters. Anodic aluminum oxide membranes were used as experimental templates, where pore radii of 28-75 nm, porosities of 0.1-0.35, and meniscus locations down to 1 μm within the pore were tested. We demonstrated different heat transfer regimes and observed more than an order of magnitude increase in dissipated heat flux by operating in the pore-level evaporation regime. The pore diameter had little effect on pore-level evaporation performance due to the negligible conduction resistance from the pore wall to the evaporating interface. The dissipated heat flux scaled with porosity as the evaporative area increased. Furthermore, moving the meniscus as little as 1 μm into the pore decreased the dissipated heat flux by more than a factor of two due to the added resistance to vapor escaping the pore. The experimental results elucidate thin film evaporation from nanopores and confirm findings of recent modeling efforts. This work also provides guidance for the design of future thin film evaporation devices for advanced thermal management. Furthermore, evaporation from nanopores is relevant to water purification, chemical separations, microfluidics, and natural processes such as transpiration.

Mitigation of Biofilm Development on Thin-Film Composite Membranes Functionalized with Zwitterionic Polymers and Silver Nanoparticles.

PubMed

Liu, Caihong; Faria, Andreia F; Ma, Jun; Elimelech, Menachem

2017-01-03

We demonstrate the functionalization of thin-film composite membranes with zwitterionic polymers and silver nanoparticles (AgNPs) for combating biofouling. Combining hydrophilic zwitterionic polymer brushes and biocidal AgNPs endows the membrane with dual functionality: antiadhesion and bacterial inactivation. An atom transfer radical polymerization (ATRP) reaction is used to graft zwitterionic poly(sulfobetaine methacrylate) (PSBMA) brushes to the membrane surface, while AgNPs are synthesized in situ through chemical reduction of silver. Two different membrane architectures (Ag-PSBMA and PSBMA-Ag TFC) are developed according to the sequence AgNPs, and PSBMA brushes are grafted on the membrane surface. A static adhesion assay shows that both modified membranes significantly reduced the adsorption of proteins, which served as a model organic foulant. However, improved antimicrobial activity is observed for PSBMA-Ag TFC (i.e., AgNPs on top of the polymer brush) in comparison to the Ag-PSBMA TFC membrane (i.e., polymer brush on top of AgNPs), indicating that architecture of the antifouling layer is an important factor in the design of zwitterion-silver membranes. Confocal laser scanning microscopy (CLSM) imaging indicated that PSBMA-Ag TFC membranes effectively inhibit biofilm formation under dynamic cross-flow membrane biofouling tests. Finally, we demonstrate the regeneration of AgNPs on the membrane after depletion of silver from the surface of the PSBMA-Ag TFC membrane.

Liquid metal electric pump

DOEpatents

Abbin, J.P.; Andraka, C.E.; Lukens, L.L.; Moreno, J.B.

1992-01-14

An electrical pump for pumping liquid metals to high pressures in high temperature environments without the use of magnets or moving mechanical parts. The pump employs a non-porous solid electrolyte membrane, typically ceramic, specific to the liquid metal to be pumped. A DC voltage is applied across the thickness of the membrane causing ions to form and enter the membrane on the electrically positive surface, with the ions being neutralized on the opposite surface. This action provides pumping of the liquid metal from one side of the non-porous solid electrolyte membrane to the other. 3 figs.

Liquid metal electric pump

DOEpatents

Abbin, Joseph P.; Andraka, Charles E.; Lukens, Laurance L.; Moreno, James B.

1992-01-01

An electrical pump for pumping liquid metals to high pressures in high temperature environments without the use of magnets or moving mechanical parts. The pump employs a non-porous solid electrolyte membrane, typically ceramic, specific to the liquid metal to be pumped. A DC voltage is applied across the thickness of the membrane causing ions to form and enter the membrane on the electrically positive surface, with the ions being neutralized on the opposite surface. This action provides pumping of the liquid metal from one side of the non-porous solid electrolyte membrane to the other.

Stripping analysis of nanomolar perchlorate in drinking water with a voltammetric ion-selective electrode based on thin-layer liquid membrane.

PubMed

Kim, Yushin; Amemiya, Shigeru

2008-08-01

A highly sensitive analytical method is required for the assessment of nanomolar perchlorate contamination in drinking water as an emerging environmental problem. We developed the novel approach based on a voltammetric ion-selective electrode to enable the electrochemical detection of "redox-inactive" perchlorate at a nanomolar level without its electrolysis. The perchlorate-selective electrode is based on the submicrometer-thick plasticized poly(vinyl chloride) membrane spin-coated on the poly(3-octylthiophene)-modified gold electrode. The liquid membrane serves as the first thin-layer cell for ion-transfer stripping voltammetry to give low detection limits of 0.2-0.5 nM perchlorate in deionized water, commercial bottled water, and tap water under a rotating electrode configuration. The detection limits are not only much lower than the action limit (approximately 246 nM) set by the U.S. Environmental Protection Agency but also are comparable to the detection limits of the most sensitive analytical methods for detecting perchlorate, that is, ion chromatography coupled with a suppressed conductivity detector (0.55 nM) or electrospray ionization mass spectrometry (0.20-0.25 nM). The mass transfer of perchlorate in the thin-layer liquid membrane and aqueous sample as well as its transfer at the interface between the two phases were studied experimentally and theoretically to achieve the low detection limits. The advantages of ion-transfer stripping voltammetry with a thin-layer liquid membrane against traditional ion-selective potentiometry are demonstrated in terms of a detection limit, a response time, and selectivity.

Enhancing the sensitivity of three-axis detectable surface acoustic wave gyroscope by using a floating thin piezoelectric membrane

NASA Astrophysics Data System (ADS)

Lee, Munhwan; Lee, Keekeun

2017-06-01

A new type of surface acoustic wave (SAW) gyroscope was developed on a floating thin piezoelectric membrane to enhance sensitivity and reliability by removing a bulk noise effect and by importing a higher amplitude of SAW. The developed device constitutes a two-port SAW resonator with a metallic dot array between two interdigital transducers (IDTs), and a one-port SAW delay line. The bulk silicon was completely etched away, leaving only a thin piezoelectric membrane with a thickness of one wavelength. A voltage controlled oscillator (VCO) was connected to a SAW resonator to activate the SAW resonator, while the SAW delay line was connected to the oscilloscope to monitor any variations caused by the Coriolis force. When the device was rotated, a secondary wave was generated, changing the amplitude of the SAW delay line. The highest sensitivity was observed in a device with a full acoustic wavelength thickness of the membrane because most of the acoustic field is confined within an acoustic wavelength thickness from the top surface; moreover, the thin-membrane-based gyroscope eliminates the bulk noise effect flowing along the bulk substrate. The obtained sensitivity and linearity of the SAW gyroscope were ˜27.5 µV deg-1 s-1 and ˜4.3%, respectively. Superior directivity was observed. The device surface was vacuum-sealed using poly(dimethylsiloxane) (PDMS) bonding to eliminate environmental interference. A three-axis detectable gyroscope was also implemented by placing three gyrosensors with the same configuration at right angles to each other on a printed circuit board.

Charge tunable thin-film composite membranes by gamma-ray triggered surface polymerization.

PubMed

Reis, Rackel; Duke, Mikel C; Tardy, Blaise L; Oldfield, Daniel; Dagastine, Raymond R; Orbell, John D; Dumée, Ludovic F

2017-06-30

Thin-film composite poly(amide) (PA) membranes have greatly diversified water supplies and food products. However, users would benefit from a control of the electrostatic interactions between the liquid and the net surface charge interface in order to benefit wider application. The ionic selectivity of the 100 nm PA semi-permeable layer is significantly affected by the pH of the solution. In this work, for the first time, a convenient route is presented to configure the surface charge of PA membranes by gamma ray induced surface grafting. This rapid and up-scalable method offers a versatile route for surface grafting by adjusting the irradiation total dose and the monomer concentration. Specifically, thin coatings obtained at low irradiation doses between 1 and 10 kGy and at low monomer concentration of 1 v/v% in methanol/water (1:1) solutions, dramatically altered the net surface charge of the pristine membranes from -25 mV to +45 mV, whilst the isoelectric point of the materials shifted from pH 3 to pH 7. This modification resulted in an improved water flux by over 55%, from 45.9 to up 70 L.m -2 .h -1 , whilst NaCl rejection was found to drop by only 1% compared to pristine membranes.

Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

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

H Ma; B Hsiao; B Chu

The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux andmore » rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.« less

Enhanced Performance of Thin Film Composite Forward Osmosis Membrane by Chemical Post-Treatment

NASA Astrophysics Data System (ADS)

Liu, Zheng; Chen, Jiangrong; Cao, Zhen; Wang, Jian; Guo, Chungang

2018-01-01

Forward osmosis is an attractive technique in water purification and desalination fields. Enhancement of the forward osmosis membrane performance is essential to the application of this technique. In this study, an optimized chemical post-treatment approach which was used to improve RO membrane performance was employed for enhancing water flux of thin film composite forward osmosis membrane. Home-made polysulfide-based forward osmosis membrane was prepared and nitric acid, sulfuric acid, ethanol, 2-propanol were employed as post-treatment solutions. After a short-term treatment, all the membrane samples manifested water flux enhancement compared with their untreated counterparts. Over 50% increase of water flux had been obtained by ethanol solution treatment. The swelling, changes of hydrophobicity and solvency in both active layer and substrate were verified as the major causes for the enhancement of the water flux. It is noted that the treatment time and solution concentration should be controlled to get both appropriate water flux and reverse salt flux. The results obtained in this study will be useful for further FO membrane development and application.

Grafting of molecularly imprinted polymer to porous polyethylene filtration membranes by plasma polymerization.

PubMed

Cowieson, D; Piletska, E; Moczko, E; Piletsky, S

2013-08-01

An application of plasma-induced grafting of polyethylene membranes with a thin layer of molecularly imprinted polymer (MIP) was presented. High-density polyethylene (HDPE) membranes, "Vyon," were used as a substrate for plasma grafting modification. The herbicide atrazine, one of the most popular targets of the molecular imprinting, was chosen as a template. The parameters of the plasma treatment were optimized in order to achieve a good balance between polymerization and ablation processes. Modified HDPE membranes were characterized, and the presence of the grafted polymeric layer was confirmed based on the observed weight gain, pore size measurements, and infrared spectrometry. Since there was no significant change in the porosity of the modified membranes, it was assumed that only a thin layer of the polymer was introduced on the surface. The experiments on the re-binding of the template atrazine to the membranes modified with MIP and blank polymers were performed. HDPE membranes which were grafted with polymer using continuous plasma polymerization demonstrated the best result which was expressed in an imprinted factor equal to 3, suggesting that molecular imprinting was successfully achieved.

Utilizing thin-film solid-phase extraction to assess the effect of organic carbon amendments on the bioavailability of DDT and dieldrin to earthworms

USDA-ARS?s Scientific Manuscript database

Improved approaches are needed to rapidly and accurately assess the bioavailability of persistent, hydrophobic organic compounds in soils at contaminated sites. The performance of a thin-film solid-phase extraction (TF-SPE) assay using vials coated with ethylene vinyl acetate polymer was compared to...

Reverse-osmosis membranes by plasma polymerization

NASA Technical Reports Server (NTRS)

Hollahan, J. R.; Wydeven, T.

1972-01-01

Thin allyl amine polymer films were developed using plasma polymerization. Resulting dry composite membranes effectively reject sodium chloride during reverse osmosis. Films are 98% sodium chloride rejective, and 46% urea rejective.

Nanoscale Solid State Batteries Enabled by Thermal Atomic Layer Deposition of a Lithium Polyphosphazene Solid State Electrolyte

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

Pearse, Alexander J.; Schmitt, Thomas E.; Fuller, Elliot J.

Several active areas of research in novel energy storage technologies, including three-dimensional solid state batteries and passivation coatings for reactive battery electrode components, require conformal solid state electrolytes. We describe an atomic layer deposition (ALD) process for a member of the lithium phosphorus oxynitride (LiPON) family, which is employed as a thin film lithium-conducting solid electrolyte. The reaction between lithium tert-butoxide (LiO tBu) and diethyl phosphoramidate (DEPA) produces conformal, ionically conductive thin films with a stoichiometry close to Li 2PO 2N between 250 and 300°C. The P/N ratio of the films is always 1, indicative of a particular polymorph ofmore » LiPON which closely resembles a polyphosphazene. Films grown at 300°C have an ionic conductivity of (6.51 ± 0.36)×10 -7 S/cm at 35°C, and are functionally electrochemically stable in the window from 0 to 5.3V vs. Li/Li +. We demonstrate the viability of the ALD-grown electrolyte by integrating it into full solid state batteries, including thin film devices using LiCoO 2 as the cathode and Si as the anode operating at up to 1 mA/cm 2. The high quality of the ALD growth process allows pinhole-free deposition even on rough crystalline surfaces, and we demonstrate the fabrication and operation of thin film batteries with the thinnest (<40nm) solid state electrolytes yet reported. Finally, we show an additional application of the moderate-temperature ALD process by demonstrating a flexible solid state battery fabricated on a polymer substrate.« less

Nanoscale Solid State Batteries Enabled by Thermal Atomic Layer Deposition of a Lithium Polyphosphazene Solid State Electrolyte

DOE PAGES

Pearse, Alexander J.; Schmitt, Thomas E.; Fuller, Elliot J.; ...

2017-04-10

Several active areas of research in novel energy storage technologies, including three-dimensional solid state batteries and passivation coatings for reactive battery electrode components, require conformal solid state electrolytes. We describe an atomic layer deposition (ALD) process for a member of the lithium phosphorus oxynitride (LiPON) family, which is employed as a thin film lithium-conducting solid electrolyte. The reaction between lithium tert-butoxide (LiO tBu) and diethyl phosphoramidate (DEPA) produces conformal, ionically conductive thin films with a stoichiometry close to Li 2PO 2N between 250 and 300°C. The P/N ratio of the films is always 1, indicative of a particular polymorph ofmore » LiPON which closely resembles a polyphosphazene. Films grown at 300°C have an ionic conductivity of (6.51 ± 0.36)×10 -7 S/cm at 35°C, and are functionally electrochemically stable in the window from 0 to 5.3V vs. Li/Li +. We demonstrate the viability of the ALD-grown electrolyte by integrating it into full solid state batteries, including thin film devices using LiCoO 2 as the cathode and Si as the anode operating at up to 1 mA/cm 2. The high quality of the ALD growth process allows pinhole-free deposition even on rough crystalline surfaces, and we demonstrate the fabrication and operation of thin film batteries with the thinnest (<40nm) solid state electrolytes yet reported. Finally, we show an additional application of the moderate-temperature ALD process by demonstrating a flexible solid state battery fabricated on a polymer substrate.« less

Proton conducting membrane using a solid acid

NASA Technical Reports Server (NTRS)

Boysen, Dane A. (Inventor); Narayanan, Sekharipuram R. (Inventor); Haile, Sossina M. (Inventor); Chisholm, Calum (Inventor)

2006-01-01

A solid acid material is used as a proton conducting membrane in an electrochemical device. The solid acid material can be one of a plurality of different kinds of materials. A binder can be added, and that binder can be either a nonconducting or a conducting binder. Nonconducting binders can be, for example, a polymer or a glass. A conducting binder enables the device to be both proton conducting and electron conducting.

Separation and purification of thymopentin with molecular imprinting membrane by solid phase extraction disks.

PubMed

Wang, Chaoli; Hu, Xiaoling; Guan, Ping; Wu, Danfeng; Qian, Liwei; Li, Ji; Song, Renyuan

2015-01-01

The synthesis and performance of molecularly imprinted membranes (MIMs) as a solid phase extraction packing materials for the separation and purification of thymopentin from crude samples was described. In order to increase structural selectivity and imprinting efficiency, surface-initiated ATRP and ionic liquid (1-vinyl-3-ethyl acetate imidazolium chloride) were used to prepare molecularly imprinting membranes. The results demonstrated that solid phase extraction disks stuffed by MIMs with ionic liquids as functional monomer demonstrated high isolation and purification of performance to the thymopentin. The molecular recognition of thymopentin was analyzed by using molecular modeling software. Copyright © 2014 Elsevier B.V. All rights reserved.

Unsupported palladium alloy membranes and methods of making same

DOEpatents

Way, J. Douglas; Thoen, Paul; Gade, Sabina K.

2015-06-02

The invention provides support-free palladium membranes and methods of making these membranes. Single-gas testing of the unsupported foils produced hydrogen permeabilities equivalent to thicker membranes produced by cold-rolling. Defect-free films as thin as 7.2 microns can be fabricated, with ideal H.sub.2/N.sub.2 selectivities as high as 40,000. Homogeneous membrane compositions may also be produced using these methods.

Highly robust thin-film composite pressure retarded osmosis (PRO) hollow fiber membranes with high power densities for renewable salinity-gradient energy generation.

PubMed

Han, Gang; Wang, Peng; Chung, Tai-Shung

2013-07-16

The practical application of pressure retarded osmosis (PRO) technology for renewable blue energy (i.e., osmotic power generation) from salinity gradient is being hindered by the absence of effective membranes. Compared to flat-sheet membranes, membranes with a hollow fiber configuration are of great interest due to their high packing density and spacer-free module fabrication. However, the development of PRO hollow fiber membranes is still in its infancy. This study aims to open up new perspectives and design strategies to molecularly construct highly robust thin film composite (TFC) PRO hollow fiber membranes with high power densities. The newly developed TFC PRO membranes consist of a selective polyamide skin formed on the lumen side of well-constructed Matrimid hollow fiber supports via interfacial polymerization. For the first time, laboratory PRO power generation tests demonstrate that the newly developed PRO hollow fiber membranes can withstand trans-membrane pressures up to 16 bar and exhibit a peak power density as high as 14 W/m(2) using seawater brine (1.0 M NaCl) as the draw solution and deionized water as the feed. We believe that the developed TFC PRO hollow fiber membranes have great potential for osmotic power harvesting.

A Novel Approach Toward Fabrication of High Performance Thin Film Composite Polyamide Membranes.

PubMed

Khorshidi, Behnam; Thundat, Thomas; Fleck, Brian A; Sadrzadeh, Mohtada

2016-02-29

A practical method is reported to enhance water permeability of thin film composite (TFC) polyamide (PA) membranes by decreasing the thickness of the selective PA layer. The composite membranes were prepared by interfacial polymerization (IP) reaction between meta-phenylene diamine (MPD)-aqueous and trimesoyl chloride (TMC)-organic solvents at the surface of polyethersulfone (PES) microporous support. Several PA TFC membranes were prepared at different temperatures of the organic solution ranging from -20 °C to 50 °C. The physico-chemical and morphological properties of the synthesized membranes were carefully characterized using serval analytical techniques. The results confirmed that the TFC membranes, synthesized at sub-zero temperatures of organic solution, had thinner and smoother PA layer with a greater degree of cross-linking and wettability compared to the PA films prepared at 50 °C. We demonstrated that reducing the temperature of organic solution effectively decreased the thickness of the PA active layer and thus enhanced water permeation through the membranes. The most water permeable membrane was prepared at -20 °C and exhibited nine times higher water flux compared to the membrane synthesized at room temperature. The method proposed in this report can be effectively applied for energy- and cost-efficient development of high performance nanofiltration and reverse osmosis membranes.

Integrating seawater desalination and wastewater reclamation forward osmosis process using thin-film composite mixed matrix membrane with functionalized carbon nanotube blended polyethersulfone support layer.

PubMed

Choi, Hyeon-Gyu; Son, Moon; Choi, Heechul

2017-10-01

Thin-film composite mixed matrix membrane (TFC MMM) with functionalized carbon nanotube (fCNT) blended in polyethersulfone (PES) support layer was synthesized via interfacial polymerization and phase inversion. This membrane was firstly tested in lab-scale integrating seawater desalination and wastewater reclamation forward osmosis (FO) process. Water flux of TFC MMM was increased by 72% compared to that of TFC membrane due to enhanced hydrophilicity. Although TFC MMM showed lower water flux than TFC commercial membrane, enhanced reverse salt flux selectivity (RSFS) of TFC MMM was observed compared to TFC membrane (15% higher) and TFC commercial membrane (4% higher), representing membrane permselectivity. Under effluent organic matter (EfOM) fouling test, 16% less normalized flux decline of TFC MMM was observed compared to TFC membrane. There was 8% less decline of TFC MMM compared to TFC commercial membrane due to fCNT effect on repulsive foulant-membrane interaction enhancement, caused by negatively charged membrane surface. After 10 min physical cleaning, TFC MMM displayed higher recovered normalized flux than TFC membrane (6%) and TFC commercial membrane (4%); this was also supported by visualized characterization of fouling layer. This study presents application of TFC MMM to integrated seawater desalination and wastewater reclamation FO process for the first time. It can be concluded that EfOM fouling of TFC MMM was suppressed due to repulsive foulant-membrane interaction. Copyright © 2017 Elsevier Ltd. All rights reserved.

Large effect of membrane tension on the fluid-solid phase transitions of two-component phosphatidylcholine vesicles.

PubMed

Chen, Dong; Santore, Maria M

2014-01-07

Model phospholipid membranes and vesicles have long provided insight into the nature of confined materials and membranes while also providing a platform for drug delivery. The rich thermodynamic behavior and interesting domain shapes in these membranes have previously been mapped in extensive studies that vary temperature and composition; however, the thermodynamic impact of tension on bilayers has been restricted to recent reports of subtly reduced fluid-fluid transition temperatures. In two-component phosphatidylcholine unilamellar vesicles [1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)], we report a dramatic influence of tension on the fluid-solid transition and resulting phases: At fixed composition, systematic variations in tension produce differently shaped solid domains (striped or irregular hexagons), shift fluid-solid transition temperatures, and produce a triple-point-like intersection of coexistence curves at elevated tensions, about 3 mN/m for 30% DOPC/70% DPPC. Tension therefore represents a potential switch of microstructure in responsive engineered materials; it is an important morphology-determining variable in confined systems, and, in biological membranes, it may provide a means to regulate dynamic structure.

Proton conducting membrane using a solid acid

NASA Technical Reports Server (NTRS)

Haile, Sossina M. (Inventor); Chisholm, Calum (Inventor); Boysen, Dane (Inventor); Narayanan, Sekharipuram R. (Inventor)

2002-01-01

A solid acid material is used as a proton conducting membrane in an electrochemical device. The solid acid material can be one of a plurality of different kinds of materials. A binder can be added, and that binder can be either a nonconducting or a conducting binder. Nonconducting binders can be, for example, a polymer or a glass. A conducting binder enables the device to be both proton conducting and electron conducting. The solid acid material has the general form M.sub.a H.sub.b (XO.sub.t).sub.c.

Method of fabricating a scalable nanoporous membrane filter

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

Tringe, Joseph W; Balhorn, Rodney L; Zaidi, Saleem

A method of fabricating a nanoporous membrane filter having a uniform array of nanopores etch-formed in a thin film structure (e.g. (100)-oriented single crystal silicon) having a predetermined thickness, by (a) using interferometric lithography to create an etch pattern comprising a plurality array of unit patterns having a predetermined width/diameter, (b) using the etch pattern to etch frustum-shaped cavities or pits in the thin film structure such that the dimension of the frustum floors of the cavities are substantially equal to a desired pore size based on the predetermined thickness of the thin film structure and the predetermined width/diameter ofmore » the unit patterns, and (c) removing the frustum floors at a boundary plane of the thin film structure to expose, open, and thereby create the nanopores substantially having the desired pore size.« less

Electron microscopy of the nuclear membrane of Amoeba proteus.

PubMed

FRAJOLA, W J; GREIDER, M H; KOSTIR, W J

1956-07-25

An electron microscope study of the nuclear membrane of Amoeba proteus by thin sectioning techniques has revealed an ultrastructure in the outer layer of the membrane that is homologous to the pores and annuli observed in the nuclear membranes of many other cell types studied by these techniques. An inner honeycombed layer apparently unique to Amoeba proteus is also described.

Preparation and Characterization of Thin-Film Composite Membrane with Nanowire-Modified Support for Forward Osmosis Process

PubMed Central

Low, Ze-Xian; Liu, Qi; Shamsaei, Ezzatollah; Zhang, Xiwang; Wang, Huanting

2015-01-01

Internal concentration polarization (ICP) in forward osmosis (FO) process is a characteristic problem for asymmetric thin-film composite (TFC) FO membrane which leads to lower water flux. To mitigate the ICP effect, modification of the substrates’ properties has been one of the most effective methods. A new polyethersulfone-based ultrafiltration membrane with increased surface porosity and high water flux was recently produced by incorporating Zn2GeO4 nanowires. The composite membrane was used as a substrate for the fabrication of TFC FO membrane, by coating a thin layer of polyamide on top of the substrate. The substrate and the nanowires were characterized by a range of techniques such as SEM, XRD, and contact angle goniometry. The water permeability and molecular weight cut-offs (MWCO) of the substrate; and the FO performance of the TFC membrane were also determined. The Zn2GeO4-modified membrane showed ~45% increase in water permeability and NaCl salt rejection of 80% under RO mode. In FO mode, the ratio of water flux to reverse solute flux was also improved. However, lower FO flux was obtained which could be due to ICP. The result shows that Zn2GO4 nanowire may be used as a modifier to the substrate to improve the quality of the polyamide layer on the substrate to improve the flux and selectivity, but not as effective in reducing ICP. This work demonstrates that the incorporation of nanomaterials to the membrane substrate may be an alternative approach to improve the formation of polyamide skin layer to achieve better FO performance. PMID:25803239

A sacrificial process for fabrication of biodegradable polymer membranes with submicron thickness.

PubMed

Beardslee, Luke A; Stolwijk, Judith; Khaladj, Dimitrius A; Trebak, Mohamed; Halman, Justin; Torrejon, Karen Y; Niamsiri, Nuttawee; Bergkvist, Magnus

2016-08-01

A new sacrificial molding process using a single mask has been developed to fabricate ultrathin 2-dimensional membranes from several biocompatible polymeric materials. The fabrication process is similar to a sacrificial microelectromechanical systems (MEMS) process flow, where a mold is created from a material that can be coated with a biodegradable polymer and subsequently etched away, leaving behind a very thin polymer membrane. In this work, two different sacrificial mold materials, silicon dioxide (SiO2 ) and Liftoff Resist (LOR) were used. Three different biodegradable materials; polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and polyglycidyl methacrylate (PGMA), were chosen as model polymers. We demonstrate that this process is capable of fabricating 200-500 nm thin, through-hole polymer membranes with various geometries, pore-sizes and spatial features approaching 2.5 µm using a mold fabricated via a single contact photolithography exposure. In addition, the membranes can be mounted to support rings made from either SU8 or PCL for easy handling after release. Cell culture compatibility of the fabricated membranes was evaluated with human dermal microvascular endothelial cells (HDMECs) seeded onto the ultrathin porous membranes, where the cells grew and formed confluent layers with well-established cell-cell contacts. Furthermore, human trabecular meshwork cells (HTMCs) cultured on these scaffolds showed similar proliferation as on flat PCL substrates, further validating its compatibility. All together, these results demonstrated the feasibility of our sacrificial fabrication process to produce biocompatible, ultra-thin membranes with defined microstructures (i.e., pores) with the potential to be used as substrates for tissue engineering applications. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1192-1201, 2016. © 2015 Wiley Periodicals, Inc.

Status of stretched-membrane heliostats

NASA Astrophysics Data System (ADS)

Alpert, D. J.; Houser, R. M.; Heckes, A. A.

1990-01-01

Since the early 1980s, Sandia National Laboratories has been developing stretched-membrane heliostats for solar central receiver power plants. They differ from conventional glass-mirror heliostats in that the optical surface is a stretched membrane -- a thin metal foil stretched over both sides of a large diameter ring. The reflective surface is provided by either a silvered-acrylic film or thin glass mirrors attached to the front membrane. Heliostats with single 14 m diameter (150 sq meter) stretched-membrane reflectors have been designed. Because of their simplicity and light weight, stretched-membrane heliostats are expected to cost up to one-third less than conventional glass-mirror designs. Two generations of 50 sq meter prototype stretched-membrane mirror modules have been built and evaluated at Sandia's Central Receiver Test Facility in Albuquerque, NM. They demonstrated that the optical performance of membrane heliostats rivals that of glass-mirror heliostats. The durability of the silvered-acrylic reflective film has improved so that a lifetime of at least 5 years is likely; methods of replacing the film in the field are being investigated. Sandia recently initiated the final phase of development: the design of fully integrated, market-ready heliostats. Field tests of these heliostats are planned to begin in FY90.

Combined membrane bioreactor (MBR) and reverse osmosis (RO) system for thin-film transistor-liquid crystal display TFT-LCD, industrial wastewater recycling.

PubMed

Chen, T K; Chen, J N

2004-01-01

In TFT-LCD industry, water plays a variety of roles as a cleaning agent and reaction solvent. As good quality water is increasingly a scarce resource and wastewater treatment costs rises, the once-through use of industrial water is becoming uneconomical and environmentally unacceptable. Instead, recycling of TFT-LCD industrial wastewater is become more attractive from both an economic and environmental perspective. This research is mainly to explore the capacity of TFT-LCD industrial wastewater recycling by the process combined with membrane bioreactor and reverse osmosis processes. Over the whole experimental period, the MBR process achieved a satisfactory organic removal. The COD could be removed with an average of over 97.3%. For TOC and BOD5 items, the average removal efficiencies were 97.8 and 99.4% respectively. The stable effluent quality and satisfactory removal performance were ensured by the efficient interception performance of the UF membrane device incorporated with biological reactor. Moreover, the MBR effluent did not contain any suspended solids and the SDI value was under 3. After treatment of RO, excellent water quality of permeate were under 5 mg/l, 2.5 mg/l and 150 micros/cm for COD, TOC and conductivity respectively. The treated water can be recycled for the cooling tower make-up water or other purposes.

Method of lift-off patterning thin films in situ employing phase change resists

DOEpatents

Bahlke, Matthias Erhard; Baldo, Marc A; Mendoza, Hiroshi Antonio

2014-09-23

Method for making a patterned thin film of an organic semiconductor. The method includes condensing a resist gas into a solid film onto a substrate cooled to a temperature below the condensation point of the resist gas. The condensed solid film is heated selectively with a patterned stamp to cause local direct sublimation from solid to vapor of selected portions of the solid film thereby creating a patterned resist film. An organic semiconductor film is coated on the patterned resist film and the patterned resist film is heated to cause it to sublime away and to lift off because of the phase change.

Electrochemically-Driven Insertion of Biological Nanodiscs into Solid State Membrane Pores as a Basis for "Pore-In-Pore" Membranes.

PubMed

Farajollahi, Farid; Seidenstücker, Axel; Altintoprak, Klara; Walther, Paul; Ziemann, Paul; Plettl, Alfred; Marti, Othmar; Wege, Christina; Gliemann, Hartmut

2018-04-13

Nanoporous membranes are of increasing interest for many applications, such as molecular filters, biosensors, nanofluidic logic and energy conversion devices. To meet high-quality standards, e.g., in molecular separation processes, membranes with well-defined pores in terms of pore diameter and chemical properties are required. However, the preparation of membranes with narrow pore diameter distributions is still challenging. In the work presented here, we demonstrate a strategy, a "pore-in-pore" approach, where the conical pores of a solid state membrane produced by a multi-step top-down lithography procedure are used as a template to insert precisely-formed biomolecular nanodiscs with exactly defined inner and outer diameters. These nanodiscs, which are the building blocks of tobacco mosaic virus-deduced particles, consist of coat proteins, which self-assemble under defined experimental conditions with a stabilizing short RNA. We demonstrate that the insertion of the nanodiscs can be driven either by diffusion due to a concentration gradient or by applying an electric field along the cross-section of the solid state membrane. It is found that the electrophoresis-driven insertion is significantly more effective than the insertion via the concentration gradient.

Electrochemically-Driven Insertion of Biological Nanodiscs into Solid State Membrane Pores as a Basis for “Pore-In-Pore” Membranes

PubMed Central

Farajollahi, Farid; Seidenstücker, Axel; Altintoprak, Klara; Walther, Paul; Ziemann, Paul; Plettl, Alfred; Wege, Christina; Gliemann, Hartmut

2018-01-01

Nanoporous membranes are of increasing interest for many applications, such as molecular filters, biosensors, nanofluidic logic and energy conversion devices. To meet high-quality standards, e.g., in molecular separation processes, membranes with well-defined pores in terms of pore diameter and chemical properties are required. However, the preparation of membranes with narrow pore diameter distributions is still challenging. In the work presented here, we demonstrate a strategy, a “pore-in-pore” approach, where the conical pores of a solid state membrane produced by a multi-step top-down lithography procedure are used as a template to insert precisely-formed biomolecular nanodiscs with exactly defined inner and outer diameters. These nanodiscs, which are the building blocks of tobacco mosaic virus-deduced particles, consist of coat proteins, which self-assemble under defined experimental conditions with a stabilizing short RNA. We demonstrate that the insertion of the nanodiscs can be driven either by diffusion due to a concentration gradient or by applying an electric field along the cross-section of the solid state membrane. It is found that the electrophoresis-driven insertion is significantly more effective than the insertion via the concentration gradient. PMID:29652841

Novel Processing of a Poly(phenyleneoxide) - b –Poly(vinylbenzyltrimethylammonium) Copolymer Anion Exchange Membrane; The Effect On Mechanical And Transport Properties

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

Pandey, Tara P.; Seifert, Soenke; Yang, Yating

2016-12-01

A poly(2,6 dimethyl 1,4-phenylene oxide)-b-poly(vinyl benzyl) chloride copolymer membranes was processed by solvent casting followed by melt pressing (SCMP) to provide uniformly thin films, 25 +/- 5 mu m, with improved conductivity, mechanical strength, water uptake, dimensional swelling, and chemical stability under 1 M KOH and 80 degrees C. These properties depended strongly on the length of the melt-pressing time. The solvent cast membranes melt pressing time was optimized to provided highly conductive membranes (high OH- conductivity of 75 +/- 25 mS cm(-1) for an IEC of 1.8 mmol g(-1) at room temperature in water). Membranes that were only solventmore » cast and not melt-pressed swelled excessively and had insufficient mechanical integrity for detailed study. When the copolymer powder was melt pressed (without prior solvent casting) at 240 degrees C and ca. 30 MPa for 20 minutes, membranes with high mechanical strength (tensile stress at break of 32 +/- 6 MPa at 25% RH and 29 +/- 3 MPa when 95% RH at 60 degrees C), high conductivity (Cl conductivity of 80 mS/cm at 90 degrees C and 95% RH), and lower water uptake were formed. However, melt pressing alone did not give larger then 5 cm x 5 cm area films, homogeneously thin (< 60 mu m), or mechanical defect-free membranes. The SCMP membranes were uniformly thin, and thermally crosslinked. The mass loss via dehydrochlorination indicated by TGA and elemental analysis confirmed the crosslinking via thermal melt pressing. The SCMP membranes thickness could be reduced by more than 50% (25 +/- 5 mu m) compared to melt pressing alone, and the Cl conductivity increased by 44% at 90 degrees C and 95% RH. The tensile stress at break of the SCMP membranes, however, was reduced by 50% at 25% RH.« less

Solid-State Water Electrolysis with an Alkaline Membrane

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

Leng, YJ; Chen, G; Mendoza, AJ

2012-06-06

We report high-performance, durable alkaline membrane water electrolysis in a solid-state cell. An anion exchange membrane (AEM) and catalyst layer ionomer for hydroxide ion conduction were used without the addition of liquid electrolyte. At 50 degrees C, an AEM electrolysis cell using iridium oxide as the anode catalyst and Pt black as the cathode catalyst exhibited a current density of 399 mA/cm(2) at 1.80 V. We found that the durability of the AEM-based electrolysis cell could be improved by incorporating a highly durable ionomer in the catalyst layer and optimizing the water feed configuration. We demonstrated an AEM-based electrolysis cellmore » with a lifetime of > 535 h. These first-time results of water electrolysis in a solid-state membrane cell are promising for low-cost, scalable hydrogen production.« less

Influence of Composition on the Thermoelectric Properties of Bi1- x Sb x Thin Films

NASA Astrophysics Data System (ADS)

Rogacheva, E. I.; Nashchekina, O. N.; Orlova, D. S.; Doroshenko, A. N.; Dresselhaus, M. S.

2017-07-01

Bi1- x Sb x solid solutions have attracted much attention as promising thermoelectric (TE) materials for cooling devices at temperatures below ˜200 K and as unique model materials for solid-state science because of a high sensitivity of their band structure to changes in composition, temperature, pressure, etc. Earlier, we revealed a non-monotonic behavior of the concentration dependences of TE properties for polycrystalline Bi1- x Sb x solid solutions and attributed these anomalies to percolation effects in the solid solution, transition to a gapless state, and to a semimetal-semiconductor transition. The goal of the present work is to find out whether the non-monotonic behavior of the concentration dependences of TE properties is observed in the thin film state as well. The objects of the study are Bi1- x Sb x thin films with thicknesses in the range d = 250-300 nm prepared by thermal evaporation of Bi1- x Sb x crystals ( x = 0-0.09) onto mica substrates. It was shown that the anomalies in the dependence of the TE properties on Bi1- x Sb x crystal composition are reproduced in thin films.

Single-crystal gallium nitride nanotubes.

PubMed

Goldberger, Joshua; He, Rongrui; Zhang, Yanfeng; Lee, Sangkwon; Yan, Haoquan; Choi, Heon-Jin; Yang, Peidong

2003-04-10

Since the discovery of carbon nanotubes in 1991 (ref. 1), there have been significant research efforts to synthesize nanometre-scale tubular forms of various solids. The formation of tubular nanostructure generally requires a layered or anisotropic crystal structure. There are reports of nanotubes made from silica, alumina, silicon and metals that do not have a layered crystal structure; they are synthesized by using carbon nanotubes and porous membranes as templates, or by thin-film rolling. These nanotubes, however, are either amorphous, polycrystalline or exist only in ultrahigh vacuum. The growth of single-crystal semiconductor hollow nanotubes would be advantageous in potential nanoscale electronics, optoelectronics and biochemical-sensing applications. Here we report an 'epitaxial casting' approach for the synthesis of single-crystal GaN nanotubes with inner diameters of 30-200 nm and wall thicknesses of 5-50 nm. Hexagonal ZnO nanowires were used as templates for the epitaxial overgrowth of thin GaN layers in a chemical vapour deposition system. The ZnO nanowire templates were subsequently removed by thermal reduction and evaporation, resulting in ordered arrays of GaN nanotubes on the substrates. This templating process should be applicable to many other semiconductor systems.

Piezoelectric thin films and their applications for electronics

NASA Astrophysics Data System (ADS)

Yoshino, Yukio

2009-03-01

ZnO and AlN piezoelectric thin films have been studied for applications in bulk acoustic wave (BAW) resonator. This article introduces methods of forming ZnO and AlN piezoelectric thin films by radio frequency sputtering and applications of BAW resonators considering the relationship between the crystallinity of piezoelectric thin films and the characteristics of the BAW resonators. Using ZnO thin films, BAW resonators were fabricated for a contour mode at 3.58 MHz and thickness modes from 200 MHz to 5 GHz. The ZnO thin films were combined with various materials, substrates, and thin films to minimize the temperature coefficient of frequency (TCF). The minimum TCF of BAW resonators was approximately 2 ppm/°C in the range -20 to 80 °C. The electromechanical coupling coefficient (k2) in a 1.9 GHz BAW resonator was 6.9%. Using AlN thin films, 5-20 GHz BAW resonators with an ultrathin membrane were realized. The membrane thickness of a 20 GHz BAW resonator was about 200 nm, k2 was 6.1%, and the quality factor (Q) was about 280. Q decreased with increasing resonant frequency. The value of k2 is almost the same for 5-20 GHz resonators. This result could be obtained by improving the thickness uniformity, by controlling internal stress of thin films, and by controlling the crystallinity of AlN piezoelectric thin film.

An asymptotic membrane model for wrinkling of very thin films

NASA Astrophysics Data System (ADS)

Battista, Antonio; Hamdouni, Aziz; Millet, Olivier

2018-05-01

In this work, a formal deduction of a two-dimensional membrane theory, similar to Landau-Lifshitz model, is performed via an asymptotic development of the weak formulation of the three-dimensional equations of elasticity. Some interesting aspects of the deduced model are investigated, in particular the property of obtaining a hyperbolic equation for the out-of-plane displacement under a certain class of boundary conditions and loads. Some simple cases are analyzed to show the relevant aspects of the model and the phenomenology that can be addressed. In particular, it is shown how this mathematical formulation is capable to describe instabilities well known as wrinkling, often observed for the buckling of very thin membranes.

Fabrication of Monolithic Sapphire Membranes for High Tc Bolometer Array Development

NASA Technical Reports Server (NTRS)

Pugel, D. E.; Lakew, B.; Aslam, S.; Wang, L.

2003-01-01

This paper examines the effectiveness of Pt/Cr thin film masks for the architecture of monolithic membrane structures in r-plane sapphire. The development of a pinhole-free Pt/Cr composite mask that is resistant to hot H2SO4:H3PO4 etchant, will lead to the fabrication of smooth sapphire membranes whose surfaces are well-suited for the growth of low-noise high Tc films. In particular, the relationship of thermal annealing conditions on the Pt/Cr composite mask system to: (1) changes in the surface morphology and elemental concentration of the Pt/Cr thin film layers and (2) etch pit formation on the sapphire surface will be presented.

Ultra-thin microporous/hybrid materials

DOEpatents

Jiang, Ying-Bing [Albuquerque, NM; Cecchi, Joseph L [Albuquerque, NM; Brinker, C Jeffrey [Albuquerque, NM

2012-05-29

Ultra-thin hybrid and/or microporous materials and methods for their fabrication are provided. In one embodiment, the exemplary hybrid membranes can be formed including successive surface activation and reaction steps on a porous support that is patterned or non-patterned. The surface activation can be performed using remote plasma exposure to locally activate the exterior surfaces of porous support. Organic/inorganic hybrid precursors such as organometallic silane precursors can be condensed on the locally activated exterior surfaces, whereby ALD reactions can then take place between the condensed hybrid precursors and a reactant. Various embodiments can also include an intermittent replacement of ALD precursors during the membrane formation so as to enhance the hybrid molecular network of the membranes.

Meteoroid capture cell construction

NASA Technical Reports Server (NTRS)

Zook, H. A.; High, R. W. (Inventor)

1976-01-01

A thin membrane covering the open side of a meteoroid capture cell causes an impacting meteoroid to disintegrate as it penetrates the membrane. The capture cell then contains and holds the meteoroid particles for later analysis.

Surface modification of ultra thin PES-zeolite using thermal annealing to increase flux and rejection of produced water treatment

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

Kusworo, T. D., E-mail: tdkusworo@che.undip.ac.id; Widayat,; Pradini, A. W.

2015-12-29

Membrane technology is an alternative of water treatment based on filtration that is being developed. Surface Modification using heat treatment has been investigated to improve the performance of ultra thin PES-Zeolite nanocomposite membrane for produced water treatment from Pertamina Balongan. Two types of membranes with surface modification and without modification were prepared to study the effect of surface modification on its permeation properties. Asymmetric ultra thin PES-Zeolite nanocomposite membrane for produced water treatment was casted using the dry/wet phase inversion technique from dope solutions containing polyethersulfone, N-methyl-2-pyrrolidone (NMP) as a solvent and zeolite as a filler. Experimental results showed thatmore » the heat treatment at near glass transition temperature was increase the rejection of COD, Turbidity and ion Ca{sup 2+}. The better adherence of zeolite particles in the polymer matrix combined with formation of charge transfer complexes (CTCs) and cross-linking might be the main factors to enhance the percent of rejection. Field emission scanning electron microscopy (FESEM) micrographs showed that the selective layer and the substructure of PES-zeolite membrane became denser and more compact after the heat treatment. The FESEM micrographs also showed that the heat treatment was increased the adherence of zeolite particle and polymer. Membranes treated at 180 °C for 15 seconds indicated increase the rejection and small decrease in flux for produced water treatment.« less

NASA Tech Briefs, May 2003

NASA Technical Reports Server (NTRS)

2003-01-01

Topics covered include: Using Diffusion Bonding in Making Piezoelectric Actuators; Wireless Temperature-Monitoring System; Analog Binaural Circuits for Detecting and Locating Leaks; Mirrors Containing Biomimetic Shape-Control Actuators; Surface-Micromachined Planar Arrays of Thermopiles; Cascade Back-Propagation Learning in Neural Networks; Perovskite Superlattices as Tunable Microwave Devices; Rollable Thin-Shell Nanolaminate Mirrors; Flight Tests of a Ministick Controller in an F/A-18 Airplane; Piezoelectrically Actuated Shutter for High Vacuum; Bio-Inspired Engineering of Exploration Systems; Microscope Cells Containing Multiple Micromachined Wells; Electrophoretic Deposition for Fabricating Microbatteries; Integrated Arrays of Ion-Sensitive Electrodes; Model of Fluidized Bed Containing Reacting Solids and Gases; Membrane Mirrors With Bimorph Shape Actuators; Using Fractional Clock-Period Delays in Telemetry Arraying; Developing Generic Software for Spacecraft Avionics; Numerical Study of Pyrolysis of Biomass in Fluidized Beds; and Assessment of Models of Chemically Reacting Granular Flows.

Studies of Atomic Free Radicals Stored in a Cryogenic Environment

NASA Technical Reports Server (NTRS)

Lee, David M.; Hubbard, Dorthy (Technical Monitor); Alexander, Glen (Technical Monitor)

2003-01-01

Impurity-Helium Solids are porous gel-like solids consisting of impurity atoms and molecules surrounded by thin layers of solid helium. They provide an ideal medium for matrix isolation of free radicals to prevent recombination and store chemical energy. In this work electron spin resonance, nuclear magnetic resonance, X-ray diffraction, and ultrasound techniques have all been employed to study the properties of these substances. Detailed studies via electron spin resonance of exchange tunneling chemical reactions involving hydrogen and deuterium molecular and atomic impurities in these solids have been performed and compared with theory. Concentrations of hydrogen approaching the quantum solid criterion have been produced. Structured studies involving X ray diffraction, ultrasound, and electron spin resonance have shown that the impurities in impurity helium solids are predominantly contained in impurity clusters, with each cluster being surrounded by thin layers of solid helium.

Membrane technology for sustainable treated wastewater reuse: agricultural, environmental and hydrological considerations.

PubMed

Oron, Gideon; Gillerman, Leonid; Bick, Amos; Manor, Yossi; Buriakovsky, Nisan; Hagin, Joseph

2008-01-01

Field experiments were conducted in agricultural fields in which secondary wastewater of the City of Arad (Israel) is reused for irrigation. For sustainable agricultural production and safe groundwater recharge the secondary effluent is further polished by a combined two-stage membrane pilot system. The pilot membrane system consists of two main in row stages: Ultrafiltration (UF) and Reverse Osmosis (RO). The UF stage is efficient in the removal of the pathogens and suspended organic matter while the successive RO stage provides safe removal of the dissolved solids (salinity). Effluents of various qualities were applied for agricultural irrigation along with continuous monitoring of the membrane system performance. Best agricultural yields were obtained when applying effluent having minimal content of dissolved solids (after the RO stage) as compared with secondary effluent without any further treatment and extended storage. In regions with shallow groundwater reduced soil salinity in the upper productive layers, maintained by extra membrane treatment, will guarantee minimal dissolved solids migration to the aquifers and minimize salinisation processes. (c) IWA Publishing 2008.

Successive membrane separation processes simplify concentration of lipases produced by Aspergillus niger by solid-state fermentation.

PubMed

Reinehr, Christian Oliveira; Treichel, Helen; Tres, Marcus Vinicius; Steffens, Juliana; Brião, Vandré Barbosa; Colla, Luciane Maria

2017-06-01

In this study, we developed a simplified method for producing, separating, and concentrating lipases derived from solid-state fermentation of agro-industrial residues by filamentous fungi. First, we used Aspergillus niger to produce lipases with hydrolytic activity. We analyzed the separation and concentration of enzymes using membrane separation processes. The sequential use of microfiltration and ultrafiltration processes made it possible to obtain concentrates with enzymatic activities much higher than those in the initial extract. The permeate flux was higher than 60 L/m 2 h during microfiltration using 20- and 0.45-µm membranes and during ultrafiltration using 100- and 50-kDa membranes, where fouling was reversible during the filtration steps, thereby indicating that the fouling may be removed by cleaning processes. These results demonstrate the feasibility of lipase production using A. niger by solid-state fermentation of agro-industrial residues, followed by successive tangential filtration with membranes, which simplify the separation and concentration steps that are typically required in downstream processes.

Fabrication and characterization of vertically aligned carbon-nanotube membranes

NASA Astrophysics Data System (ADS)

Castellano, Richard; Akin, Cevat; Purri, Matt; Shan, Jerry; Kim, Sangil; Fornasiero, Francesco

2015-11-01

Membranes having vertically-aligned carbon-nanotube (VACNT) pores offer promise as highly efficient and permeable membranes for use as breathable thin films, or in filtration and separation applications, among others. However, current membrane-fabrication techniques utilizing chemical-vapor-deposition-grown VACNT arrays are costly and difficult to scale up. We have developed a solution-based, electric-field-assisted approach as a cost-effective and scalable method to produce large-area VACNT membranes. Nanotubes are dispersed in a liquid polymer, and aligned and electrodeposited with the aid of an electric field prior to crosslinking the polymer to create VACNT membranes. We experimentally examine the electrodeposition process, focusing on parameters including the electric field, composition of the solution, and CNT functionalization that can affect the nanotube number density in the resulting membrane. We characterize the CNT pore size and number density and investigate the transport properties of the membrane. Size-exclusion tests are used to check for defects and infer the pore size of the VACNT membranes. Dry-gas membrane permeability is measured with a pressurized nitrogen-flow system, while moisture-vapor-transfer rate is measured with the ASTM-E96 upright-cup test. We discuss the measured transport properties of the solution-based, electric-field-fabricated VACNT membranes in reference to their application as breathable thin films. We would like to acknowledge DTRA for their funding and support of our research.

Substrate-Independent Robust and Heparin-Mimetic Hydrogel Thin Film Coating via Combined LbL Self-Assembly and Mussel-Inspired Post-Cross-linking.

PubMed

Ma, Lang; Cheng, Chong; He, Chao; Nie, Chuanxiong; Deng, Jie; Sun, Shudong; Zhao, Changsheng

2015-12-02

In this work, we designed a robust and heparin-mimetic hydrogel thin film coating via combined layer-by-layer (LbL) self-assembly and mussel-inspired post-cross-linking. Dopamine-grafted heparin-like/-mimetic polymers (DA-g-HepLP) with abundant carboxylic and sulfonic groups were synthesized by the conjugation of adhesive molecule, DA, which exhibited substrate-independent adhesive affinity to various solid surfaces because of the formation of irreversible covalent bonds. The hydrogel thin film coated substrates were prepared by a three-step reaction: First, the substrates were coated with DA-g-HepLP to generate negatively charged surfaces. Then, multilayers were obtained via LbL coating of chitosan and the DA-g-HepLP. Finally, the noncovalent multilayers were oxidatively cross-linked by NaIO4. Surface ATR-FTIR and XPS spectra confirmed the successful fabrication of the hydrogel thin film coatings onto membrane substrates; SEM images revealed that the substrate-independent coatings owned 3D porous morphology. The soaking tests in highly alkaline, acid, and concentrated salt solutions indicated that the cross-linked hydrogel thin film coatings owned high chemical resistance. In comparison, the soaking tests in physiological solution indicated that the cross-linked hydrogel coatings owned excellent long-term stability. The live/dead cell staining and morphology observations of the adhered cells revealed that the heparin-mimetic hydrogel thin film coated substrates had low cell toxicity and high promotion ability for cell proliferation. Furthermore, systematic in vitro investigations of protein adsorption, platelet adhesion, blood clotting, and blood-related complement activation confirmed that the hydrogel film coated substrates showed excellent hemocompatibility. Both the results of inhibition zone and bactericidal activity indicated that the gentamycin sulfate loaded hydrogel thin films had significant inhibition capability toward both Escherichia coli and Staphylococcus aureus bacteria. Combined the above advantages, it is believed that the designed heparin-mimetic hydrogel thin films may show high potential for applications in various biological and clinical fields, such as long-term hemocompatible and drug-loading materials for implants.

Decomposition of poly(amide-imide) film enameled on solid copper wire using atmospheric pressure non-equilibrium plasma.

PubMed

Sugiyama, Kazuo; Suzuki, Katsunori; Kuwasima, Shusuke; Aoki, Yosuke; Yajima, Tatsuhiko

2009-01-01

The decomposition of a poly(amide-imide) thin film coated on a solid copper wire was attempted using atmospheric pressure non-equilibrium plasma. The plasma was produced by applying microwave power to an electrically conductive material in a gas mixture of argon, oxygen, and hydrogen. The poly(amide-imide) thin film was easily decomposed by argon-oxygen mixed gas plasma and an oxidized copper surface was obtained. The reduction of the oxidized surface with argon-hydrogen mixed gas plasma rapidly yielded a metallic copper surface. A continuous plasma heat-treatment process using a combination of both the argon-oxygen plasma and argon-hydrogen plasma was found to be suitable for the decomposition of the poly(amide-imide) thin film coated on the solid copper wire.

Resonant modal group theory of membrane-type acoustical metamaterials for low-frequency sound attenuation

NASA Astrophysics Data System (ADS)

Ma, Fuyin; Wu, Jiu Hui; Huang, Meng

2015-09-01

In order to overcome the influence of the structural resonance on the continuous structures and obtain a lightweight thin-layer structure which can effectively isolate the low-frequency noises, an elastic membrane structure was proposed. In the low-frequency range below 500 Hz, the sound transmission loss (STL) of this membrane type structure is greatly higher than that of the current sound insulation material EVA (ethylene-vinyl acetate copo) of vehicle, so it is possible to replace the EVA by the membrane-type metamaterial structure in practice engineering. Based on the band structure, modal shapes, as well as the sound transmission simulation, the sound insulation mechanism of the designed membrane-type acoustic metamaterials was analyzed from a new perspective, which had been validated experimentally. It is suggested that in the frequency range above 200 Hz for this membrane-mass type structure, the sound insulation effect was principally not due to the low-level locally resonant mode of the mass block, but the continuous vertical resonant modes of the localized membrane. So based on such a physical property, a resonant modal group theory is initially proposed in this paper. In addition, the sound insulation mechanism of the membrane-type structure and thin plate structure were combined by the membrane/plate resonant theory.

Preparation and Characterization of Chitosan Thin Films on Mixed-Matrix Membranes for Complete Removal of Chromium

PubMed Central

Nayak, Vignesh; Jyothi, Mannekote Shivanna; Balakrishna, R Geetha; Padaki, Mahesh; Ismail, Ahmad Fauzi

2015-01-01

Herein we present a new approach for the complete removal of CrVI species, through reduction of CrVI to CrIII, followed by adsorption of CrIII. Reduction of chromium from water is an important challenge, as CrIV is one of the most toxic substances emitted from industrial processes. Chitosan (CS) thin films were developed on plain polysulfone (PSf) and PSf/TiO2 membrane substrates by a temperature-induced technique using polyvinyl alcohol as a binder. Structure property elucidation was carried out by X-ray diffraction, microscopy, spectroscopy, contact angle measurement, and water uptake studies. The increase in hydrophilicity followed the order: PSf < PSf/TiO2 < PSf/TiO2/CS membranes. Use of this thin-film composite membrane for chromium removal was investigated with regards to the effects of light and pH. The observations reveal 100 % reduction of CrVI to CrIII through electrons and protons donated from OH and NH2 groups of the CS layer; the reduced CrIII species are adsorbed onto the CS layer via complexation to give chromium-free water. PMID:26246989

Strong thin membrane structure for use as solar sail comprising substrate with reflective coating on one surface and an infra red emissivity increasing coating on the other surface

NASA Technical Reports Server (NTRS)

Frazer, Robert E. (Inventor)

1982-01-01

Production of strong lightweight membrane structure by applying a thin reflective coating such as aluminum to a rotating cylinder, applying a mesh material such as nylon over the aluminum coating, coating the mesh overlying the aluminum with a polymerizing material such as a para-xylylene monomer gas to polymerize as a film bound to the mesh and the aluminum, and applying an emissivity increasing material such as chromium and silicon monoxide to the polymer film to disperse such material colloidally into the growing polymer film, or applying such material to the final polymer film, and removing the resulting membrane structure from the cylinder. Alternatively, such membrane structure can be formed by etching a substrate in the form of an organic film such as a polyimide, or a metal foil, to remove material from the substrate and reduce its thickness, applying a thin reflective coating such as aluminum on one side of the substrate and applying an emissivity increasing coating such as chromium and silicon monoxide on the reverse side of the substrate.

Influence of film structure on the dewetting kinetics of thin polymer films in the solvent annealing process.

PubMed

Zhang, Huanhuan; Xu, Lin; Lai, Yuqing; Shi, Tongfei

2016-06-28

On a non-wetting solid substrate, the solvent annealing process of a thin polymer film includes the swelling process and the dewetting process. Owing to difficulties in the in situ analysis of the two processes simultaneously, a quantitative study on the solvent annealing process of thin polymer films on the non-wetting solid substrate is extremely rare. In this paper, we design an experimental method by combining spectroscopic ellipsometry with optical microscopy to achieve the simultaneous in situ study. Using this method, we investigate the influence of the structure of swollen film on its dewetting kinetics during the solvent annealing process. The results show that for a thin PS film with low Mw (Mw = 4.1 kg mol(-1)), acetone molecules can form an ultrathin enriched layer between the PS film and the solid substrate during the swelling process. The presence of the acetone enriched layer accounts for the exponential kinetic behavior in the case of a thin PS film with low Mw. However, the acetone enriched layer is not observed in the case of a thin PS film with high Mw (Mw = 400 kg mol(-1)) and the slippage effect of polymer chains is valid during the dewetting process.

Specific considerations for obtaining appropriate La1-xSrxGa1-yMgyO3-δ thin films using pulsed-laser deposition and its influence on the performance of solid-oxide fuel cells

NASA Astrophysics Data System (ADS)

Hwang, Jaeyeon; Lee, Heon; Lee, Jong-Ho; Yoon, Kyung Joong; Kim, Hyoungchul; Hong, Jongsup; Son, Ji-Won

2015-01-01

To obtain La1-xSrxGa1-yMgyO3-δ (LSGM) thin films with the appropriate properties, pulsed-laser deposition (PLD) is employed, and specific considerations regarding control of the deposition parameters is investigated. It is demonstrated that with a target of stoichiometric composition, appropriate LSGM thin films cannot be produced because of the deviation of the composition from the target to the thin film. Only after adjusting the target composition an LSGM thin film with an appropriate composition and phase can be obtained. The optimized LSGM thin film possesses an electrical conductivity close to that of the bulk LSGM. In contrast, non-optimized thin films do not yield any measurable electrical conductivity. The impact of the optimization of the LSGM thin-film electrolyte on the cell performance is quite significant, in that a solid-oxide fuel cell (SOFC) with an optimized LSGM thin-film electrolyte produces a maximum power density of 1.1 W cm-2 at 600 °C, whereas an SOFC with a non-optimal LSGM thin-film electrolyte is not operable.

Multifield analysis of a piezoelectric valveless micropump: effects of actuation frequency and electric potential

NASA Astrophysics Data System (ADS)

Sayar, Ersin; Farouk, Bakhtier

2012-07-01

Coupled multifield analysis of a piezoelectrically actuated valveless micropump device is carried out for liquid (water) transport applications. The valveless micropump consists of two diffuser/nozzle elements; the pump chamber, a thin structural layer (silicon), and a piezoelectric layer, PZT-5A as the actuator. We consider two-way coupling of forces between solid and liquid domains in the systems where actuator deflection causes fluid flow and vice versa. Flow contraction and expansion (through the nozzle and the diffuser respectively) generate net fluid flow. Both structural and flow field analysis of the microfluidic device are considered. The effect of the driving power (voltage) and actuation frequency on silicon-PZT-5A bi-layer membrane deflection and flow rate is investigated. For the compressible flow formulation, an isothermal equation of state for the working fluid is employed. The governing equations for the flow fields and the silicon-PZT-5A bi-layer membrane motions are solved numerically. At frequencies below 5000 Hz, the predicted flow rate increases with actuation frequency. The fluid-solid system shows a resonance at 5000 Hz due to the combined effect of mechanical and fluidic capacitances, inductances, and damping. Time-averaged flow rate starts to drop with increase of actuation frequency above (5000 Hz). The velocity profile in the pump chamber becomes relatively flat or plug-like, if the frequency of pulsations is sufficiently large (high Womersley number). The pressure, velocity, and flow rate prediction models developed in the present study can be utilized to optimize the design of MEMS based micropumps.

[Morphological pathology of classic Kaposi's sarcoma. Ultrastructural studies and reflections on histogenesis].

PubMed

Holzhausen, H J; Stiller, D; Sachs, M

1988-01-01

Histological and electron-microscopic studies were conducted into biopsy material from cases of what is called the classical type of idiopathic Kaposi's sarcoma without acquired immunodeficiency syndrome. Ultrastructural analysis was conducted, with the view to characterizing a possible progenitor cell from which the angioblastic and fibroblastic elements were likely to originate. The biopsy material had been obtained from two males, aged 86 or 83 years, who had been afflicted with the disease for 18 or 8 years. The nodular lesions were typical of Kaposi's sarcoma and were, histologically, made up of variable mixtures of vascular and spindle cell elements. The angiomatous structures were a capillary meshwork or sinusoidal patterns lined by atypical endothelial cells. The spindle cell areas contained large numbers of slit-like spaces which were without endothelial lining but were stuffed with erythrocytes. Flattened endothelioid cells were recordable from semi-thin-sections of some clefts. Haemosiderin was, typically, deposited in places. Electron microscopically, the endothelial cells of vascular channels exhibited varying amounts of characteristic organelles, such as Weibel-Palade bodies, microfilaments and pinocytotic vesicles as well as basal membranes. Cells with typical endothelial markers, too, were detectable in solid sprouts or in capillary-like differentiations with narrow or small lumina. The spindle cell tumour areas consisted of fibroblastic cells with plenty of rough endoplasmic reticulum and surrounded by material of basal membrane nature. Also visible were solid, sprout-type multilayer cell complexes surrounded by basal membranes which exhibited undifferentiated or primitive cellular forms, endothelioid and pericytic. Transitional forms from these complexes to the above vascular tumours or the spindle-cell formations were detectable. These ultrastructural findings might be interpreted to the effect that an angioblastically determined mesenchymal cell, a so-called endothelioblast, was thinkable and was discussed as the precursor cell of atypical vascular and spindle cell proliferation in Kaposi's sarcoma.

Solid Lubricants for Oil-Free Turbomachinery

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher

2005-01-01

Recent breakthroughs in gas foil bearing solid lubricants and computer based modeling has enabled the development of revolulionary Oil-Free turbomachinery systems. These innovative new and solid lubricants at low speeds (start-up and shut down). Foil bearings are hydrodynamic, self acting fluid film bearings made from thin, flexible sheet metal foils. These thin foils trap a hydrodynamic lubricating air film between their surfaces and moving shaft surface. For low temperature applications, like ainrafl air cycle machines (ACM's), polymer coatings provide important solid lubrication during start-up and shut down prior to the development of the lubricating fluid film. The successful development of Oil-Free gas turbine engines requires bearings which can operate at much higher temperatures (greater than 300 C). To address this extreme solid lubrication need, NASA has invented a new family of compostie solid lubricant coatings, NASA PS300.

Internal Membrane Control in Azotobacter vinelandii

PubMed Central

Pate, Jack L.; Shah, Vinod K.; Brill, Winston J.

1973-01-01

Azotobacter vinelandii was grown on N2, NH4+, or NO3−, and an internal membrane network was observed by electron microscopy of thin sections of cells. Cells obtained in early exponential growth contained less internal membrane than did cells from cultures in late exponential growth. It seems likely that O2 has a role in regulating the amount of internal membrane structure. Images PMID:4123239

Super-Anticoagulant Heparin-Mimicking Hydrogel Thin Film Attached Substrate Surfaces to Improve Hemocompatibility.

PubMed

He, Min; Cui, Xiaofei; Jiang, Huiyi; Huang, Xuelian; Zhao, Weifeng; Zhao, Changsheng

2017-02-01

In this study, heparin-mimicking hydrogel thin films are covalently attached onto poly(ether sulfone) membrane surfaces to improve anticoagulant property. The hydrogel films display honeycomb-like porous structure with well controlled thickness and show long-term stability. After immobilizing the hydrogel films, the membranes show excellent anticoagulant property confirmed by the activated partial thromboplastin time values exceeding 600 s. Meanwhile, the thrombin time values increase from 20 to 61 s as the sodium allysulfonate proportions increase from 0 to 80 mol%. In vitro investigations of protein adsorption and blood-related complement activation also confirm that the membranes exhibit super-anticoagulant property. Furthermore, gentamycin sulfate is loaded into the hydrogel films, and the released drug shows significant inhibition toward E. coli bacteria. It is believed that the surface attached heparin-mimicking hydrogel thin films may show high potential for the applications in various biological fields, such as blood contacting materials and drug loading materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Strong thin membrane structure. [solar sails

NASA Technical Reports Server (NTRS)

Frazer, R. E. (Inventor)

1979-01-01

A continuous process is described for producing strong lightweight structures for use as solar sails for spacecraft propulsion by radiation pressure. A thin reflective coating, such as aluminum, is applied to a rotating cylinder. A nylon mesh, applied over the aluminum coating, is then coated with a polymerizing material such as a para-xylylene monomer gas to polymerize as a film bound to the mesh and the aluminum. An emissivity increasing material such as chromium or silicon monoxide is applied to the polymer film to disperse such material colloidally into the growing polymer film, or to the final polymer film. The resulting membrane structure is then removed from the cylinder. Alternately, the membrane structure can be formed by etching a substrate in the form of an organic film such as a polymide, or a metal foil, to remove material from the substrate and reduce its thickness. A thin reflective coating (aluminum) is applied on one side of the substrate, and an emissivity increasing coating is applied on the reverse side of the substrate.

Hydrogen production by high temperature water splitting using electron conducting membranes

DOEpatents

Balachandran, Uthamalingam; Wang, Shuangyan; Dorris, Stephen E.; Lee, Tae H.

2006-08-08

A device and method for separating water into hydrogen and oxygen is disclosed. A first substantially gas impervious solid electron-conducting membrane for selectively passing protons or hydrogen is provided and spaced from a second substantially gas impervious solid electron-conducting membrane for selectively passing oxygen. When steam is passed between the two membranes at dissociation temperatures the hydrogen from the dissociation of steam selectively and continuously passes through the first membrane and oxygen selectively and continuously passes through the second membrane, thereby continuously driving the dissociation of steam producing hydrogen and oxygen. The oxygen is thereafter reacted with methane to produce syngas which optimally may be reacted in a water gas shift reaction to produce CO₂ and H₂.

Scaling during capillary thinning of particle-laden drops

NASA Astrophysics Data System (ADS)

Thete, Sumeet; Wagoner, Brayden; Basaran, Osman

2017-11-01

A fundamental understanding of drop formation is crucial in many applications such as ink-jet printing, microfluidic devices, and atomization. During drop formation, the about-to-form drop is connected to the fluid hanging from the nozzle via a thinning filament. Therefore, the physics of capillary thinning of filaments is key to understanding drop formation and has been thoroughly studied for pure Newtonian fluids using theory, simulations, and experiments. In some of the applications however, the forming drop and hence the thinning filament may contain solid particles. The thinning dynamics of such particle-laden filaments differs radically from that of particle-free filaments. Moreover, our understanding of filament thinning in the former case is poor compared to that in the latter case despite the growing interest in pinch-off of particle-laden filaments. In this work, we go beyond similar studies and experimentally explore the impact of solid particles on filament thinning by measuring both the radial and axial scalings in the neck region. The results are summarized in terms of a phase diagram of capillary thinning of particle-laden filaments.

Palladium-bacterial cellulose membranes for fuel cells.

PubMed

Evans, Barbara R; O'Neill, Hugh M; Malyvanh, Valerie P; Lee, Ida; Woodward, Jonathan

2003-07-01

Bacterial cellulose is a versatile renewable biomaterial that can be used as a hydrophilic matrix for the incorporation of metals into thin, flexible, thermally stable membranes. In contrast to plant cellulose, we found it catalyzed the deposition of metals within its structure to generate a finely divided homogeneous catalyst layer. Experimental data suggested that bacterial cellulose possessed reducing groups capable of initiating the precipitation of palladium, gold, and silver from aqueous solution. Since the bacterial cellulose contained water equivalent to at least 200 times the dry weight of the cellulose, it was dried to a thin membranous structure suitable for the construction of membrane electrode assemblies (MEAs). Results of our study with palladium-cellulose showed that it was capable of catalyzing the generation of hydrogen when incubated with sodium dithionite and generated an electrical current from hydrogen in an MEA containing native cellulose as the polyelectrolyte membrane (PEM). Advantages of using native and metallized bacterial cellulose membranes in an MEA over other PEMs such as Nafion 117 include its higher thermal stability to 130 degrees C and lower gas crossover.

Mechanical properties of monolayer graphene oxide.

PubMed

Suk, Ji Won; Piner, Richard D; An, Jinho; Ruoff, Rodney S

2010-11-23

Mechanical properties of ultrathin membranes consisting of one layer, two overlapped layers, and three overlapped layers of graphene oxide platelets were investigated by atomic force microscopy (AFM) imaging in contact mode. In order to evaluate both the elastic modulus and prestress of thin membranes, the AFM measurement was combined with the finite element method (FEM) in a new approach for evaluating the mechanics of ultrathin membranes. Monolayer graphene oxide was found to have a lower effective Young's modulus (207.6 ± 23.4 GPa when a thickness of 0.7 nm is used) as compared to the value reported for "pristine" graphene. The prestress (39.7-76.8 MPa) of the graphene oxide membranes obtained by solution-based deposition was found to be 1 order of magnitude lower than that obtained by others for mechanically cleaved graphene. The novel AFM imaging and FEM-based mapping methods presented here are of general utility for obtaining the elastic modulus and prestress of thin membranes.

Extending the 3ω method: thermal conductivity characterization of thin films.

PubMed

Bodenschatz, Nico; Liemert, André; Schnurr, Sebastian; Wiedwald, Ulf; Ziemann, Paul

2013-08-01

A lock-in technique for measurement of thermal conductivity and volumetric heat capacity of thin films is presented. The technique is based on the 3ω approach using electrical generation and detection of oscillatory heat along a thin metal strip. Thin films are deposited onto the backside of commercial silicon nitride membranes, forming a bilayer geometry with distinct thermal parameters. Stepwise comparison to an adapted heat diffusion model delivers these parameters for both layers. Highest sensitivity is found for metallic thin films.

Electrochemical Cell for Obtaining Oxygen from Carbon Dioxide Atmospheres

NASA Technical Reports Server (NTRS)

Hooker, Matthew; Rast, H. Edward; Rogers, Darren K.; Borja, Luis; Clark, Kevin; Fleming, Kimberly; Mcgurren, Michael; Oldaker, Tom; Sweet, Nanette

1989-01-01

To support human life on the Martian surface, an electrochemical device will be required to obtain oxygen from the carbon dioxide rich atmosphere. The electrolyte employed in such a device must be constructed from extremely thin, dense membranes to efficiently acquire the oxygen necessary to support life. A forming process used industrially in the production of multilayer capacitors and electronic substrates was adapted to form the thin membranes required. The process, known as the tape casting, involves the suspension consisting of solvents and binders. The suspension is passed under a blade, resulting in the production of ceramic membranes between 0.1 and 0.5 mm thick. Once fired, the stabilized zirconia membranes were assembled into the cell design by employing a zirconium phosphate solution as the sealing agent. The resulting ceramic-to-ceramic seals were found to be structurally sound and gas-tight. Furthermore, by using a zirconia-based solution to assemble the cell, the problem of a thermal expansion mismatch was alleviated. By adopting an industrial forming process to produce thin membranes, an electrochemical cell for obtaining oxygen from carbon dioxide was produced. The proposed cell design is unique in that it does not require a complicated manifold system for separating the various gases present in this process, nor does it require a series of complex electrical connections. Thus, the device can reliably obtain the vital oxygen supply from the toxic carbon dioxide atmosphere.

Bilayer membrane interactions with nanofabricated scaffolds

DOE PAGES

Collier, C. Patrick

2015-07-29

Membrane function is facilitated by lateral organization within the lipid bilayer, including phase-separation of lipids into more ordered domains (lipid rafts) and anchoring of the membrane to a cytoskeleton. These features have proven difficult to reproduce in model membrane systems such as black lipid membranes, unilamellar vesicles and supported bilayers. However, advances in micro/nanofabrication have resulted in more realistic synthetic models of membrane-cytoskeleton interactions that can help uncover the design rules responsible for biological membrane formation and organization. This review will focus on describing micro-/nanostructured scaffolds that can emulate the connections of a cellular membrane to an underlying “cytoskeleton”. Thismore » includes molecular-based scaffolds anchored to a solid substrate through surface chemistry, solid-state supports modified by material deposition, lithography and etching, the creation of micro/nanoporous arrays, integration with microfluidics, and droplet-based bilayers at interfaces. Lastly, model systems such as these are increasing our understanding of structure and organization in cell membranes, and how they result in the emergence of functionality at the nanoscale.« less

MODIFIED REVERSE OSMOSIS SYSTEM FOR TREATMENT OF PRODUCED WATERS

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

T.M. Whitworth; Liangxiong Li

2002-09-15

This report describes work performed during the second year of the project ''Modified reverse osmosis system for treatment of produced waters.'' We performed two series of reverse osmosis experiments using very thin bentonite clay membranes compacted to differing degrees. The first series of 10 experiments used NaCl solutions with membranes that ranged between 0.041 and 0.064mm in thickness. Our results showed compaction of such ultra-thin clay membranes to be problematic. The thickness of the membranes was exceeded by the dimensional variation in the machined experimental cell and this is believed to have resulted in local bypassing of the membrane withmore » a resultant decrease in solute rejection efficiency. In two of the experiments, permeate flow was varied as a percentage of the total flow to investigate results of changing permeate flow on solute rejection. In one experiment, the permeate flow was varied between 2.4 and 10.3% of the total flow with no change in solute rejection. In another experiment, the permeate flow was varied between 24.6 and 52.5% of the total flow. In this experiment, the solute rejection rate decreased as the permeate occupied greater fractions of the total flow. This suggests a maximum solute rejection efficiency for these clay membranes for a permeate flow of between 10.3 and 24.6% of the total; flow. Solute rejection was found to decrease with increasing salt concentration and ranged between 62.9% and 19.7% for chloride and between 61.5 and 16.8% for sodium. Due to problems with the compaction procedure and potential membrane bypassing, these rejection rates are probably not the upper limit for NaCl rejection by bentonite membranes. The second series of four reverse osmosis experiments was conducted with a 0.057mm-thick bentonite membrane and dilutions of a produced water sample with an original TDS of 196,250 mg/l obtained from a facility near Loco Hill, New Mexico, operated by an independent. These experiments tested the separation efficiency of the bentonite membrane for each of the dilutions. We found that membrane efficiency decreased with increasing solute concentration and with increasing TDS. The rejection of SO{sub 4}{sup 2-} was greater than Cl{sup -}. This may be because the SO{sub 4}{sup 2-} concentration was much lower than the Cl{sup -} concentration in the waters tested. The cation rejection sequence varied with solute concentration and TDS. The solute rejection sequence for multi-component solutions is difficult to predict for synthetic membranes; it may not be simple for clay membranes either. The permeate flows in our experiments were 4.1 to 5.4% of the total flow. This suggests that very thin clay membranes may be useful for some separations. Work on development of a spiral-wound clay membrane module found that it is difficult to maintain compaction of the membrane if the membrane is rolled and then inserted in the outer tube. A different design was tried using a cylindrical clay membrane and this also proved difficult to assemble with adequate membrane compaction. The next step is to form the membrane in place using hydraulic pressure on a thin slurry of clay in either water or a nonpolar organic solvent such as ethanol. Technology transfer efforts included four manuscripts submitted to peer-reviewed journals, two abstracts, and chairing a session on clays as membranes at the Clay Minerals Society annual meeting.« less

Polysulfone thin film composite nanofiltration membranes for removal of textile dyes wastewater

NASA Astrophysics Data System (ADS)

Sutedja, Andrew; Aileen Josephine, Claresta; Mangindaan, Dave

2017-12-01

This research was conducted to produce nanofiltration (NF) membranes, which have good performance in terms of removal of textile dye (Reactive Red 120, RR120) from simulated wastewater as one of several eco-engineering developments for sustainable water resource management. Phase inversion technique was utilized to fabricate the membrane with polysulfone (PSF) support, dissolved in N-methyl-2 pyrollidone (NMP) solvent, and diethylene glycol (DEG) as non-solvent additive. The fabricated membrane then modified with the additional of dopamine coating and further modified by interfacial polymerization (IP) to form a thin film composite (TFC)-NF membrane with PSF substrate. TFC was formed from interaction between amine monomer (2 %-weight of m-phenylenediamine (MPD) in deionized water) and acyl chloride (0.2 %-weight of trimesoyl chloride (TMC) in hexane). From this study, the fabricated PSF-TFC membrane could remove dyestuff from RR120 wastewater by 88% rejection at 120 psi. The result of this study is promising to be applied in Indonesia where researches on removal of dyes from textile wastewater by using membranes are still quite rare. Therefore, this paper may open new avenues for development of eco-engineering development in Indonesia.

Impacts of zeolite nanoparticles on substrate properties of thin film nanocomposite membranes for engineered osmosis

NASA Astrophysics Data System (ADS)

Salehi, Tahereh Mombeini; Peyravi, Majid; Jahanshahi, Mohsen; Lau, Woei-Jye; Rad, Ali Shokuhi

2018-04-01

In this work, microporous substrates modified by zeolite nanoparticles were prepared and used for composite membrane making with the aim of reducing internal concentration polarization (ICP) effect of membranes during engineered osmosis applications. Nanocomposite substrates were fabricated via phase inversion technique by embedding nanostructured zeolite (clinoptilolite) in the range of 0-0.6 wt% into matrix of polyethersulfone (PES) substrate. Of all the substrates prepared, the PES0.4 substrate (with 0.4 wt% zeolite) exhibited unique characteristics, i.e., increased surface porosity, lower structural parameter ( S) (from 0.78 to 0.48 mm), and enhanced water flux. The thin film nanocomposite (TFN) membrane made of this optimized substrate was also reported to exhibit higher water flux compared to the control composite membrane during forward osmosis (FO) and pressure-retarded osmosis (PRO) test, without compromising reverse solute flux. The water flux of such TFN membrane was 43% higher than the control TFC membrane (1.93 L/m2 h bar) with salt rejection recorded at 94.7%. An increment in water flux is ascribed to the reduction in structural parameter, leading to reduced ICP effect.

Simple fabrication of 12 μm thin nanocomposite fuel cell membranes by direct electrospinning and printing

NASA Astrophysics Data System (ADS)

Breitwieser, Matthias; Klose, Carolin; Klingele, Matthias; Hartmann, Armin; Erben, Johannes; Cho, Hyeongrae; Kerres, Jochen; Zengerle, Roland; Thiele, Simon

2017-01-01

Direct membrane deposition (DMD) was recently introduced as a novel polymer electrolyte membrane fabrication method. Here, this approach is extended to fabricate 12 μm thin nanocomposite fuel cell membranes. Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) nanofibers are directly electrospun onto gas diffusion electrodes. By inkjet-printing Nafion ionomer dispersion into the pore space of PVDF-HFP nanofiber mats, composite membranes of 12 μm thickness were fabricated. At 120 °C and 35% relative humidity, stoichiometric 1.5/2.5 H2/air flow and atmospheric pressure, the power density of the DMD fuel cell (0.19 W cm-2), was about 1.7 times higher than that of the reference fuel cell (0.11 W cm-2) with Nafion HP membrane and identical catalyst. A lower ionic resistance and, especially at 120 °C, a reduced charge transfer resistance is found compared to the Nafion HP membrane. A 100 h accelerated stress test revealed a voltage decay of below 0.8 mV h-1, which is in the range of literature values for significantly thicker reinforced membranes. Finally, this novel fabrication approach enables new degrees of freedom in the design of complex composite membranes. The presented combination of scalable deposition techniques has the potential to simplify and thus reduce cost of composite membrane fabrication at a larger scale.

Modeling the Voltage Dependence of Electrochemical Reactions at Solid-Solid and Solid-Liquid Interfaces in Batteries

NASA Astrophysics Data System (ADS)

Leung, Kevin

2015-03-01

Electrochemical reactions at electrode/electrolyte interfaces are critically dependent on the total electrochemical potential or voltage. In this presentation, we briefly review ab initio molecular dynamics (AIMD)-based estimate of voltages on graphite basal and edge planes, and then apply similar concepts to solid-solid interfaces relevant to lithium ion and Li-air batteries. Thin solid films on electrode surfaces, whether naturally occuring during power cycling (e.g., undesirable lithium carbonate on Li-air cathodes) or are artificially introduced, can undergo electrochemical reactions as the applied voltage varies. Here the onset of oxidation of lithium carbonate and other oxide thin films on model gold electrode surfaces is correlated with the electronic structure in the presence/absence of solvent molecules. Our predictions help determine whether oxidation first occurs at the electrode-thin film or electrolyte-thin film interface. Finally, we will critically compare the voltage estimate methodology used in the fuel cell community with the lithium cohesive energy calibration method broadly applied in the battery community, and discuss why they may yield different predictions. This work was supported by Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DESC0001160. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Deparment of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Polyacrylate microspheres composite for all-solid-state reference electrodes.

PubMed

Kisiel, Anna; Donten, Mikołaj; Mieczkowski, Józef; Rius-Ruiz, F Xavier; Maksymiuk, Krzysztof; Michalska, Agata

2010-09-01

A novel concept is proposed for the encapsulation of components within polyacrylate microspheres, prior to their incorporation into a membrane phase. Thus finer and better controlled dispersion of heterogeneous membrane components can be achieved. This concept was verified by using a poly(n-butyl acrylate) membrane-based reference electrode as an example. In this example the proper dispersion of solid constituents of the heterogeneous membrane and prevention of their leakage are both of primary importance. Potassium chloride-loaded poly(n-butyl acrylate) microspheres were prepared and then left in contact with silver nitrate to convert some of the KCl into AgCl. The material obtained was introduced into a poly(n-butyl acrylate) membrane. The reference electrode membranes obtained in this way were characterized with much more stable potential (both in different electrolytes and over time) compared with electrodes prepared by the direct introduction of KCl and AgCl to the membrane.

Thin film ion conducting coating

DOEpatents

Goldner, Ronald B.; Haas, Terry; Wong, Kwok-Keung; Seward, George

1989-01-01

Durable thin film ion conducting coatings are formed on a transparent glass substrate by the controlled deposition of the mixed oxides of lithium:tantalum or lithium:niobium. The coatings provide durable ion transport sources for thin film solid state storage batteries and electrochromic energy conservation devices.

Aquaporin-Based Biomimetic Polymeric Membranes: Approaches and Challenges

PubMed Central

Habel, Joachim; Hansen, Michael; Kynde, Søren; Larsen, Nanna; Midtgaard, Søren Roi; Jensen, Grethe Vestergaard; Bomholt, Julie; Ogbonna, Anayo; Almdal, Kristoffer; Schulz, Alexander; Hélix-Nielsen, Claus

2015-01-01

In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs: aquaporin proteins (AQPs), block copolymers for AQP reconstitution, and polymer-based supporting structures. First, we briefly cover challenges and review recent developments in understanding the interplay between AQP and block copolymers. Second, we review some experimental characterization methods for investigating AQP incorporation including freeze-fracture transmission electron microscopy, fluorescence correlation spectroscopy, stopped-flow light scattering, and small-angle X-ray scattering. Third, we focus on recent efforts in embedding reconstituted AQPs in membrane designs that are based on conventional thin film interfacial polymerization techniques. Finally, we describe some new developments in interfacial polymerization using polyhedral oligomeric silsesquioxane cages for increasing the physical and chemical durability of thin film composite membranes. PMID:26264033

Thin Polymer Films with Continuous Vertically Aligned 1 nm Pores Fabricated by Soft Confinement

DOE PAGES

Feng, Xunda; Nejati, Siamak; Cowan, Matthew G.; ...

2015-12-03

Membrane separations are critically important in areas ranging from health care and analytical chemistry to bioprocessing and water purification. An ideal nanoporous membrane would consist of a thin film with physically continuous and vertically aligned nanopores and would display a narrow distribution of pore sizes. However, the current state of the art departs considerably from this ideal and is beset by intrinsic trade-offs between permeability and selectivity. We demonstrate an effective and scalable method to fabricate polymer films with ideal membrane morphologies consisting of submicron thickness films with physically continuous and vertically aligned 1 nm pores. The approach is basedmore » on soft confinement to control the orientation of a cross-linkable mesophase in which the pores are produced by self-assembly. The scalability, exceptional ease of fabrication, and potential to create a new class of nanofiltration membranes stand out as compelling aspects.« less

Ultra-thin alumina and silicon nitride MEMS fabricated membranes for the electron multiplication

NASA Astrophysics Data System (ADS)

Prodanović, V.; Chan, H. W.; Graaf, H. V. D.; Sarro, P. M.

2018-04-01

In this paper we demonstrate the fabrication of large arrays of ultrathin freestanding membranes (tynodes) for application in a timed photon counter (TiPC), a novel photomultiplier for single electron detection. Low pressure chemical vapour deposited silicon nitride (Si x N y ) and atomic layer deposited alumina (Al2O3) with thicknesses down to only 5 nm are employed for the membrane fabrication. Detailed characterization of structural, mechanical and chemical properties of the utilized films is carried out for different process conditions and thicknesses. Furthermore, the performance of the tynodes is investigated in terms of secondary electron emission, a fundamental attribute that determines their applicability in TiPC. Studied features and presented fabrication methods may be of interest for other MEMS application of alumina and silicon nitride as well, in particular where strong ultra-thin membranes are required.

Honeycomb-alumina supported garnet membrane: Composite electrolyte with low resistance and high strength for lithium metal batteries

NASA Astrophysics Data System (ADS)

Liu, Kai; Wang, Chang-An

2015-05-01

Li-ion ceramic electrolyte material is considered the key for advanced lithium metal batteries, and garnet-type oxides are promising ceramic electrolyte materials. To disentangle the thinness-strength dilemma in garnet-type Li6.4La3Zr1.4Ta0.6O12 (LLZTO) electrolyte, we designed and successfully synthesized a ceramic-ceramic composite electrolyte, i.e. a honeycomb-Al2O3 pellet supported LLZTO membrane. The honeycomb-Al2O3 pellet acts as a supporter to the thin LLZTO membrane and makes the whole composite electrolyte strong enough, while the straight holes in the Al2O3 supporter can be filled with liquid electrolyte and acts as channels for Li+ transportation. Such a composite design eliminates the concern over the LLZTO membrane's fragility, and keeps its good electrical property.

Fuel cell membranes and crossover prevention

DOEpatents

Masel, Richard I [Champaign, IL; York, Cynthia A [Newington, CT; Waszczuk, Piotr [White Bear Lake, MN; Wieckowski, Andrzej [Champaign, IL

2009-08-04

A membrane electrode assembly for use with a direct organic fuel cell containing a formic acid fuel includes a solid polymer electrolyte having first and second surfaces, an anode on the first surface and a cathode on the second surface and electrically linked to the anode. The solid polymer electrolyte has a thickness t:.gtoreq..times..times..times..times. ##EQU00001## where C.sub.f is the formic acid fuel concentration over the anode, D.sub.f is the effective diffusivity of the fuel in the solid polymer electrolyte, K.sub.f is the equilibrium constant for partition coefficient for the fuel into the solid polymer electrolyte membrane, I is Faraday's constant n.sub.f is the number of electrons released when 1 molecule of the fuel is oxidized, and j.sub.f.sup.c is an empirically determined crossover rate of fuel above which the fuel cell does not operate.

Multiplexed Colorimetric Solid-Phase Extraction

NASA Technical Reports Server (NTRS)

Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.

2009-01-01

Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

Removal of Pb(II) from wastewater using Al2O3-NaA zeolite composite hollow fiber membranes synthesized from solid waste coal fly ash.

PubMed

Zhu, Li; Ji, Jiayou; Wang, Shulin; Xu, Chenxi; Yang, Kun; Xu, Man

2018-09-01

Al 2 O 3 -NaA zeolite composite hollow fiber membranes were successfully fabricated via hydrothermal synthesis by using industrial solid waste coal fly ash and porous Al 2 O 3 hollow fiber supports. The as-synthesized Al 2 O 3 -NaA zeolite composite hollow fiber membranes were then characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The hollow fiber membranes were used to remove lead ions (Pb(II), 50 mg L -1 ) from synthetic wastewater with a removal efficiency of 99.9% at 0.1 MPa after 12 h of filtration. This study showed that the Al 2 O 3 -NaA zeolite composite hollow fiber membranes (the pore size of the membrane was about 0.41 nm in diameter) synthesized from coal fly ash could be efficiently used for treating low concentration Pb(II) wastewater. It recycled solid waste coal fly ash not only to solve its environment problems, but also can produce high-value Al 2 O 3 -NaA zeolite composite hollow fiber membranes for separation application in treating wastewater containing Pb(II). Copyright © 2018 Elsevier Ltd. All rights reserved.

Effect of the Process Parameters on the Formability, Microstructure, and Mechanical Properties of Thin Plates Fabricated by Rheology Forging Process with Electromagnetic Stirring Method

NASA Astrophysics Data System (ADS)

Jin, Chul Kyu; Jang, Chang Hyun; Kang, Chung Gil

2014-01-01

A thin plate (150 × 150 × 1.2 mm) with embedded corrugation is fabricated using the rheoforming method. Semisolid slurry is created using the electromagnetic stirring (EMS) system, and the thin plate is made with the forging die at the 200-ton hydraulic press. The cross sections and microstructures of the slurry with and without stirring are examined. To investigate the effect of the process parameters on the formability, microstructure, and mechanical properties of thin plate the slurry is subjected to 16 types of condition for the forging experiment. The 16 types included the following conditions: Whether the EMS is applied or not, three fractions of the solid phase at 35, 45 and 55 pct; two compression velocities at 30 and 300 mm s-1; and four different compression pressures—100, 150, 200 and 250 MPa. The thin plate's formability is enhanced at higher punch velocity for compressing the slurry, and fine solid particles are uniformly distributed, which in turn, enhances the plate's mechanical properties. The pressure between 150 and 200 MPa is an appropriate condition to form thin plates. A thin plate without defects can be created when the slurry at 35 pct of the solid fraction (f s) was applied at the compression velocity of 300 mm s-1 and 150 MPa of pressure. The surface state of thin plate is excellent with 220 MPa of tensile strength and 13.5 pct of elongation. The primary particles are fine over the entire plate, and there are no liquid segregation-related defects.

Direct deposit of catalyst on the membrane of direct feed fuel cells

NASA Technical Reports Server (NTRS)

Chun, William (Inventor); Narayanan, Sekharipuram R. (Inventor); Jeffries-Nakamura, Barbara (Inventor); Valdez, Thomas I. (Inventor); Linke, Juergen (Inventor)

2001-01-01

An improved direct liquid-feed fuel cell having a solid membrane electrolyte for electrochemical reactions of an organic fuel. Catalyst utilization and catalyst/membrane interface improvements are disclosed. Specifically, the catalyst layer is applied directly onto the membrane electrolyte.

Fabrication of Monolithic Sapphire Membranes for High T(sub c) Bolometer Array Development

NASA Technical Reports Server (NTRS)

Pugel, D. E.; Lakew, B.; Aslam, S.; Wang, L.

2004-01-01

This paper examines the effectiveness of Pt/Cr thin film masks for the architecture of monolithic membrane structures in r-plane single crystal sapphire. The development of a pinhole-free Pt/Cr composite mask that is resistant to boiling H2SO4:H3PO4 etchant will lead to the fabrication of smooth sapphire membranes whose surfaces are well-suited for the growth of low-noise high Tc films. In particular, the relationship of thermal annealing conditions on the Pt/Cr composite mask system to: (1) changes in the surface morphology (2) elemental concentration of the Pt/Cr thin film layers and (3) etch pit formation on the sapphire surface will be presented.

Generic instabilities in a fluid membrane coupled to a thin layer of ordered active polar fluid.

PubMed

Sarkar, Niladri; Basu, Abhik

2013-08-01

We develop an effective two-dimensional coarse-grained description for the coupled system of a planar fluid membrane anchored to a thin layer of polar ordered active fluid below. The macroscopic orientation of the active fluid layer is assumed to be perpendicular to the attached membrane. We demonstrate that activity or nonequilibrium drive of the active fluid makes such a system generically linearly unstable for either signature of a model parameter [Formula: see text] [Formula: see text] that characterises the strength of activity. Depending upon boundary conditions and within a range of the model parameters, underdamped propagating waves may be present in our model. We discuss the phenomenological significance of our results.

Cell micro-irradiation with MeV protons counted by an ultra-thin diamond membrane

NASA Astrophysics Data System (ADS)

Barberet, Philippe; Pomorski, Michal; Muggiolu, Giovanna; Torfeh, Eva; Claverie, Gérard; Huss, Cédric; Saada, Samuel; Devès, Guillaume; Simon, Marina; Seznec, Hervé

2017-12-01

We report the development of thin single crystal diamond membranes suitable for dose control in targeted cell irradiation experiments with a proton microbeam. A specific design was achieved to deliver single protons with a hit detection efficiency approaching 100%. The membranes have thicknesses between 1.8 and 3 μm and are used as vacuum windows on the microbeam line. The impact of these transmission detectors on the microbeam spot size is estimated by Monte-Carlo simulations, indicating that a beam lateral resolution below 2 μm is achieved. This is confirmed by experiments showing the accumulation online of X-ray Repair Cross-Complementing protein 1 (XRCC1)-Green Fluorescent Protein (GFP) at DNA damaged sites in living cells.

Fluid-structure interaction involving large deformations: 3D simulations and applications to biological systems

NASA Astrophysics Data System (ADS)

Tian, Fang-Bao; Dai, Hu; Luo, Haoxiang; Doyle, James F.; Rousseau, Bernard

2014-02-01

Three-dimensional fluid-structure interaction (FSI) involving large deformations of flexible bodies is common in biological systems, but accurate and efficient numerical approaches for modeling such systems are still scarce. In this work, we report a successful case of combining an existing immersed-boundary flow solver with a nonlinear finite-element solid-mechanics solver specifically for three-dimensional FSI simulations. This method represents a significant enhancement from the similar methods that are previously available. Based on the Cartesian grid, the viscous incompressible flow solver can handle boundaries of large displacements with simple mesh generation. The solid-mechanics solver has separate subroutines for analyzing general three-dimensional bodies and thin-walled structures composed of frames, membranes, and plates. Both geometric nonlinearity associated with large displacements and material nonlinearity associated with large strains are incorporated in the solver. The FSI is achieved through a strong coupling and partitioned approach. We perform several validation cases, and the results may be used to expand the currently limited database of FSI benchmark study. Finally, we demonstrate the versatility of the present method by applying it to the aerodynamics of elastic wings of insects and the flow-induced vocal fold vibration.

Fluid–structure interaction involving large deformations: 3D simulations and applications to biological systems

PubMed Central

Tian, Fang-Bao; Dai, Hu; Luo, Haoxiang; Doyle, James F.; Rousseau, Bernard

2013-01-01

Three-dimensional fluid–structure interaction (FSI) involving large deformations of flexible bodies is common in biological systems, but accurate and efficient numerical approaches for modeling such systems are still scarce. In this work, we report a successful case of combining an existing immersed-boundary flow solver with a nonlinear finite-element solid-mechanics solver specifically for three-dimensional FSI simulations. This method represents a significant enhancement from the similar methods that are previously available. Based on the Cartesian grid, the viscous incompressible flow solver can handle boundaries of large displacements with simple mesh generation. The solid-mechanics solver has separate subroutines for analyzing general three-dimensional bodies and thin-walled structures composed of frames, membranes, and plates. Both geometric nonlinearity associated with large displacements and material nonlinearity associated with large strains are incorporated in the solver. The FSI is achieved through a strong coupling and partitioned approach. We perform several validation cases, and the results may be used to expand the currently limited database of FSI benchmark study. Finally, we demonstrate the versatility of the present method by applying it to the aerodynamics of elastic wings of insects and the flow-induced vocal fold vibration. PMID:24415796

Interplay between membrane curvature and protein conformational equilibrium investigated by solid-state NMR.

PubMed

Liao, Shu Y; Lee, Myungwoon; Hong, Mei

2018-03-01

Many membrane proteins sense and induce membrane curvature for function, but structural information about how proteins modulate their structures to cause membrane curvature is sparse. We review our recent solid-state NMR studies of two virus membrane proteins whose conformational equilibrium is tightly coupled to membrane curvature. The influenza M2 proton channel has a drug-binding site in the transmembrane (TM) pore. Previous chemical shift data indicated that this pore-binding site is lost in an M2 construct that contains the TM domain and a curvature-inducing amphipathic helix. We have now obtained chemical shift perturbation, protein-drug proximity, and drug orientation data that indicate that the pore-binding site is restored when the full cytoplasmic domain is present. This finding indicates that the curvature-inducing amphipathic helix distorts the TM structure to interfere with drug binding, while the cytoplasmic tail attenuates this effect. In the second example, we review our studies of a parainfluenza virus fusion protein that merges the cell membrane and the virus envelope during virus entry. Chemical shifts of two hydrophobic domains of the protein indicate that both domains have membrane-dependent backbone conformations, with the β-strand structure dominating in negative-curvature phosphatidylethanolamine (PE) membranes. 31 P NMR spectra and 1 H- 31 P correlation spectra indicate that the β-strand-rich conformation induces saddle-splay curvature to PE membranes and dehydrates them, thus stabilizing the hemifusion state. These results highlight the indispensable role of solid-state NMR to simultaneously determine membrane protein structures and characterize the membrane curvature in which these protein structures exist. Copyright © 2018 Elsevier Inc. All rights reserved.

The thermomechanical stability of micro-solid oxide fuel cells fabricated on anodized aluminum oxide membranes

NASA Astrophysics Data System (ADS)

Kwon, Chang-Woo; Lee, Jae-Il; Kim, Ki-Bum; Lee, Hae-Weon; Lee, Jong-Ho; Son, Ji-Won

2012-07-01

The thermomechanical stability of micro-solid oxide fuel cells (micro-SOFCs) fabricated on an anodized aluminum oxide (AAO) membrane template is investigated. The full structure consists of the following layers: AAO membrane (600 nm)/Pt anode/YSZ electrolyte (900 nm)/porous Pt cathode. The utilization of a 600-nm-thick AAO membrane significantly improves the thermomechanical stability due to its well-known honeycomb-shaped nanopore structure. Moreover, the Pt anode layer deposited in between the AAO membrane and the YSZ electrolyte preserves its integrity in terms of maintaining the triple-phase boundary (TPB) and electrical conductivity during high-temperature operation. Both of these results guarantee thermomechanical stability of the micro-SOFC and extend the cell lifetime, which is one of the most critical issues in the fabrication of freestanding membrane-type micro-SOFCs.

Characterization of Polyethylene-Graft-Sulfonated Polyarylsulfone Proton Exchange Membranes for Direct Methanol Fuel Cell Applications.

PubMed

Kim, Hyung Kyu; Zhang, Gang; Nam, Changwoo; Chung, T C Mike

2015-12-04

This paper examines polymer film morphology and several important properties of polyethylene-graft-sulfonated polyarylene ether sulfone (PE-g-s-PAES) proton exchange membranes (PEMs) for direct methanol fuel cell applications. Due to the extreme surface energy differences between a semi-crystalline and hydrophobic PE backbone and several amorphous and hydrophilic s-PAES side chains, the PE-g-s-PAES membrane self-assembles into a unique morphology, with many proton conductive s-PAES channels embedded in the stable and tough PE matrix and a thin hydrophobic PE layer spontaneously formed on the membrane surfaces. In the bulk, these membranes show good mechanical properties (tensile strength >30 MPa, Young's modulus >1400 MPa) and low water swelling (λ < 15) even with high IEC >3 mmol/g in the s-PAES domains. On the surface, the thin hydrophobic and semi-crystalline PE layer shows some unusual barrier (protective) properties. In addition to exhibiting higher through-plane conductivity (up to 160 mS/cm) than in-plane conductivity, the PE surface layer minimizes methanol cross-over from anode to cathode with reduced fuel loss, and stops the HO• and HO₂• radicals, originally formed at the anode, entering into PEM matrix. Evidently, the thin PE surface layer provides a highly desirable protecting layer for PEMs to reduce fuel loss and increase chemical stability. Overall, the newly developed PE-g-s-PAES membranes offer a desirable set of PEM properties, including conductivity, selectivity, mechanical strength, stability, and cost-effectiveness for direct methanol fuel cell applications.

Characterization of Polyethylene-Graft-Sulfonated Polyarylsulfone Proton Exchange Membranes for Direct Methanol Fuel Cell Applications

PubMed Central

Kim, Hyung Kyu; Zhang, Gang; Nam, Changwoo; Chung, T.C. Mike

2015-01-01

This paper examines polymer film morphology and several important properties of polyethylene-graft-sulfonated polyarylene ether sulfone (PE-g-s-PAES) proton exchange membranes (PEMs) for direct methanol fuel cell applications. Due to the extreme surface energy differences between a semi-crystalline and hydrophobic PE backbone and several amorphous and hydrophilic s-PAES side chains, the PE-g-s-PAES membrane self-assembles into a unique morphology, with many proton conductive s-PAES channels embedded in the stable and tough PE matrix and a thin hydrophobic PE layer spontaneously formed on the membrane surfaces. In the bulk, these membranes show good mechanical properties (tensile strength >30 MPa, Young’s modulus >1400 MPa) and low water swelling (λ < 15) even with high IEC >3 mmol/g in the s-PAES domains. On the surface, the thin hydrophobic and semi-crystalline PE layer shows some unusual barrier (protective) properties. In addition to exhibiting higher through-plane conductivity (up to 160 mS/cm) than in-plane conductivity, the PE surface layer minimizes methanol cross-over from anode to cathode with reduced fuel loss, and stops the HO• and HO2• radicals, originally formed at the anode, entering into PEM matrix. Evidently, the thin PE surface layer provides a highly desirable protecting layer for PEMs to reduce fuel loss and increase chemical stability. Overall, the newly developed PE-g-s-PAES membranes offer a desirable set of PEM properties, including conductivity, selectivity, mechanical strength, stability, and cost-effectiveness for direct methanol fuel cell applications. PMID:26690232

Asymmetric block copolymer membranes with ultrahigh porosity and hierarchical pore structure by plain solvent evaporation.

PubMed

Yu, H; Qiu, X; Behzad, A R; Musteata, V; Smilgies, D-M; Nunes, S P; Peinemann, K-V

2016-10-04

Membranes with a hierarchical porous structure could be manufactured from a block copolymer blend by pure solvent evaporation. Uniform pores in a 30 nm thin skin layer supported by a macroporous structure were formed. This new process is attractive for membrane production because of its simplicity and the lack of liquid waste.

Nanoscale Probing of Electrical Signals in Biological Systems

DTIC Science & Technology

2012-03-18

Membranes Anodized aluminum oxide ( AAO ) is an ideal prototype substrate for studying ion transport through nanoporous membranes . For optimal...electrochemical microscopy, scanning ion conductance microscopy, nanoporous membranes , anodized aluminum oxide , atomic layer deposition, focused ion beam...capacity. This approach utilizes atomic layer deposition (ALD) of a thin conformal Ir film into a nanoporous anodized aluminum oxide (

Functional, photochemically active, and chemically asymmetric membranes by interfacial polymerization of derivatized multifunctional prepolymers

DOEpatents

Lonsdale, Harold K.; Wamser, Carl C.

1988-01-01

The preparation of a novel class of thin film membranes by interfacial polymerization is disclosed, said membanes incorporating as part of their polymeric structure the functionality of monomeric or oligomeric precursors. Specific embodiments include porphyrin and phthalocyanime derivatives that are photochemically or electrochemically active, as well as chemically asymmetric membranes.

Defect-free ultrahigh flux asymmetric membranes

DOEpatents

Pinnau, Ingo; Koros, William J.

1990-01-01

Defect-free, ultrahigh flux integrally-skinned asymmetric membranes having extremely thin surface layers (<0.2 .mu.m) comprised of glassy polymers are disclosed. The membranes are formed by casting an appropriate drope followed by forced convective evaporation of solvent to obtain a dry phase separated asymmetrical structure. The structure is then washed in a precipitation liquid and dried.

Zeolite-imidazolate framework (ZIF-8) membrane synthesis on a mixed-matrix substrate.

PubMed

Barankova, Eva; Pradeep, Neelakanda; Peinemann, Klaus-Viktor

2013-10-21

A thin, dense, compact and hydrogen selective ZIF-8 membrane was synthesized on a polymer/metal oxide mixed-matrix support by a secondary seeding method. The new concept of incorporating ZnO particles into the support and PDMS coating of the ZIF-8 layer is introduced to improve the preparation of ZIF-polymer composite membranes.

Methods for using novel cathode and electrolyte materials for solid oxide fuel cells and ion transport membranes

DOEpatents

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

2016-01-12

Methods using novel cathode, electrolyte and oxygen separation materials operating at intermediate temperatures for use in solid oxide fuel cells and ion transport membranes include oxides with perovskite related structures and an ordered arrangement of A site cations. The materials have significantly faster oxygen kinetics than in corresponding disordered perovskites.

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

DOEpatents

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

2014-01-28

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

Method for Synthesizing Metal Nanowires in Anodic Alumina Membranes Using Solid State Reduction

NASA Technical Reports Server (NTRS)

Martinez-Inesta, Maria M (Inventor); Feliciano, Jennie (Inventor); Quinones-Fontalvo, Leonel (Inventor)

2016-01-01

The invention proposes a novel method for the fabrication of regular arrays of MNWs using solid-state reduction (SSR). Using this method copper (Cu), silver (Ag), and palladium (Pd) nanowire (NWs) arrays were synthesized using anodic alumina membranes (AAMs) as templates. Depending on the metal loading used the NWs reached different diameters.

Checkerboard deposition of lithium manganese oxide spinel (LiMn2O4) by RF magnetron sputtering on a stainless steel in all-solid-state thin film battery

NASA Astrophysics Data System (ADS)

Hsueh, T. H.; Yu, Y. Q.; Jan, D. J.; Su, C. H.; Chang, S. M.

2018-03-01

All-solid-state thin film lithium batteries (TFLBs) are the most competitive low-power sources to be applied in various kinds of micro-electro-mechanical systems and have been draw a lot of attention in academic research. In this paper, the checkerboard deposition of all-solid-state TFLB was composed of thin film lithium metal anode, lithium phosphorus oxynitride (LiPON) solid electrolyte, and checkerboard deposition of lithium manganese oxide spinel (LiMn2O4) cathode. The LiPON and LiMn2O4 were deposited by a radio frequency magnetron sputtering system, and the lithium metal was deposited by a thermal evaporation coater. The electrochemical characterization of this lithium battery showed the first discharge capacity of 107.8 μAh and the capacity retention was achieved 95.5% after 150 charge-discharge cycles between 4.3V and 3V at a current density of 11 μA/cm2 (0.5C). Obviously, the checkerboard of thin film increased the charge exchange rate; also this lithium battery exhibited high C-rate performance, with better capacity retention of 82% at 220 μA/cm2 (10C).

Enzymatically active high-flux selectively gas-permeable membranes

DOEpatents

Jiang, Ying-Bing; Cecchi, Joseph L.; Rempe, Susan; FU, Yaqin; Brinker, C. Jeffrey

2016-01-26

An ultra-thin, catalyzed liquid transport medium-based membrane structure fabricated with a porous supporting substrate may be used for separating an object species such as a carbon dioxide object species. Carbon dioxide flux through this membrane structures may be several orders of magnitude higher than traditional polymer membranes with a high selectivity to carbon dioxide. Other gases such as molecular oxygen, molecular hydrogen, and other species including non-gaseous species, for example ionic materials, may be separated using variations to the membrane discussed.

Qualification of the RSRM case membrane case-to-insulation bondline inspection using the Thiokol Corporation ultrasonic RSRM bondline inspection system

NASA Technical Reports Server (NTRS)

Cook, M.

1990-01-01

Qualification testing of Combustion Engineering's AMDATA Intraspect/98 Data Acquisition and Imaging System that applies to the redesigned solid rocket motor (RSRM) case membrane case-to-insulation bondline inspection was performed. Testing was performed at M-67, the Thiokol Corp. RSRM Assembly Facility. The purpose of the inspection was to verify the integrity of the case membrane case-to-insulation bondline. The case membrane scanner was calibrated on the redesigned solid rocket motor case segment calibration standard, which had an intentional 1.0 by 1.0 in. case-to-insulation unbond. The case membrane scanner was then used to scan a 20 by 20 in. membrane area of the case segment. Calibration of the scanner was then rechecked on the calibration standard to ensure that the calibration settings did not change during the case membrane scan. This procedure was successfully performed five times to qualify the unbond detection capability of the case membrane scanner.

Vanadium Redox Flow Batteries Using meta-Polybenzimidazole-Based Membranes of Different Thicknesses.

PubMed

Noh, Chanho; Jung, Mina; Henkensmeier, Dirk; Nam, Suk Woo; Kwon, Yongchai

2017-10-25

15, 25, and 35 μm thick meta-polybenzimidazole (PBI) membranes are doped with H 2 SO 4 and tested in a vanadium redox flow battery (VRFB). Their performances are compared with those of Nafion membranes. Immersed in 2 M H 2 SO 4 , PBI absorbs about 2 mol of H 2 SO 4 per mole of repeat unit. This results in low conductivity and low voltage efficiency (VE). In ex-situ tests, meta-PBI shows a negligible crossover of V 3+ and V 4+ ions, much lower than that of Nafion. This is due to electrostatic repulsive forces between vanadium cations and positively charged protonated PBI backbones, and the molecular sieving effect of PBI's nanosized pores. It turns out that charge efficiency (CE) of VRFBs using meta-PBI-based membranes is unaffected by or slightly increases with decreasing membrane thickness. Thick meta-PBI membranes require about 100 mV larger potentials to achieve the same charging current as thin meta-PBI membranes. This additional potential may increase side reactions or enable more vanadium ions to overcome the electrostatic energy barrier and to enter the membrane. On this basis, H 2 SO 4 -doped meta-PBI membranes should be thin to achieve high VE and CE. The energy efficiency of 15 μm thick PBI reaches 92%, exceeding that of Nafion 212 and 117 (N212 and N117) at 40 mA cm -2 .

Nanofiltration of Mine Water: Impact of Feed pH and Membrane Charge on Resource Recovery and Water Discharge

PubMed Central

Mullett, Mark; Fornarelli, Roberta; Ralph, David

2014-01-01

Two nanofiltration membranes, a Dow NF 270 polyamide thin film and a TriSep TS 80 polyamide thin film, were investigated for their retention of ionic species when filtering mine influenced water streams at a range of acidic pH values. The functional iso-electric point of the membranes, characterized by changes in retention over a small pH range, were examined by filtering solutions of sodium sulphate. Both membranes showed changes in retention at pH 3, suggesting a zero net charge on the membranes at this pH. Copper mine drainage and synthetic solutions of mine influenced water were filtered using the same membranes. These solutions were characterized by pH values within 2 and 5, thus crossing the iso-electric point of both membranes. Retention of cations was maximized when the feed solution pH was less than the iso-electric point of the membrane. In these conditions, the membrane has a net positive charge, reducing the transmission rate of cations. From the recoveries of a range of cations, the suitability of nanofiltration was discussed relative to the compliance with mine water discharge criteria and the recovery of valuable commodity metals. The nanofiltration process was demonstrated to offer advantages in metal recovery from mine waste streams, concomitantly enabling discharge criteria for the filtrate disposal to be met. PMID:24957170

The reasons for the high power density of fuel cells fabricated with directly deposited membranes

NASA Astrophysics Data System (ADS)

Vierrath, Severin; Breitwieser, Matthias; Klingele, Matthias; Britton, Benjamin; Holdcroft, Steven; Zengerle, Roland; Thiele, Simon

2016-09-01

In a previous study, we reported that polymer electrolyte fuel cells prepared by direct membrane deposition (DMD) produced power densities in excess of 4 W/cm2. In this study, the underlying origins that give rise to these high power densities are investigated and reported. The membranes of high power, DMD-fabricated fuel cells are relatively thin (12 μm) compared to typical benchmark, commercially available membranes. Electrochemical impedance spectroscopy, at high current densities (2.2 A/cm2) reveals that mass transport resistance was half that of reference, catalyst-coated-membranes (CCM). This is attributed to an improved oxygen supply in the cathode catalyst layer by way of a reduced propensity of flooding, and which is facilitated by an enhancement in the back diffusion of water from cathode to anode through the thin directly deposited membrane. DMD-fabricated membrane-electrode-assemblies possess 50% reduction in ionic resistance (15 mΩcm2) compared to conventional CCMs, with contributions of 9 mΩcm2 for the membrane resistance and 6 mΩcm2 for the contact resistance of the membrane and catalyst layer ionomer. The improved mass transport is responsible for 90% of the increase in power density of the DMD fuel cell, while the reduced ionic resistance accounts for a 10% of the improvement.

Mechanics of Fluctuating Elastic Plates and Fiber Networks

NASA Astrophysics Data System (ADS)

Liang, Xiaojun

Lipid membranes and fiber networks in biological systems perform important mechanical functions at the cellular and tissue levels. In this thesis I delve into two detailed problems--thermal fluctuation of membranes and non-linear compression response of fiber networks. Typically, membrane fluctuations are analysed by decomposing into normal modes or by molecular simulations. In the first part of my thesis, I propose a new semi-analytic method to calculate the partition function of a membrane. The membrane is viewed as a fluctuating von Karman plate and discretized into triangular elements. Its energy is expressed as a function of nodal displacements, and then the partition function and co-variance matrix are computed using Gaussian integrals. I recover well-known results for the dependence of the projected area of a lipid bilayer membrane on the applied tension, and recent simulation results on the ependence of membrane free energy on geometry, spontaneous curvature and tension. As new applications I use this technique to study a membrane with heterogeneity and different boundary conditions. I also use this technique to study solid membranes by taking account of the non-linear coupling of in-plane strains with out-of-plane deflections using a penalty energy, and apply it to graphene, an ultra-thin two-dimensional solid. The scaling of graphene fluctuations with membrane size is recovered. I am able to capture the dependence of the thermal expansion coefficient of graphene on temperature. Next, I study curvature mediated interactions between inclusions in membranes. I assume the inclusions to be rigid, and show that the elastic and entropic forces between them can compete to yield a local maximum in the free energy if the membrane bending modulus is small. If the spacing between the inclusions is less than this local maximum then the attractive entropic forces dominate and the separation between the inclusions will be determined by short range interactions; if the spacing is more than the local maximum then the elastic repulsive forces dominate and the inclusions will move further apart. This technique can be extended to account for entropic effects in other methods which rely on quadratic energies to study the interactions of inclusions in membranes. In the second part of this thesis I study the compression response of two fiber network materials--blood clots and carbon nanotube forests. The stress-strain curve of both materials reveals four characteristic regions, for compression-decompression: 1) linear elastic region; 2) upper plateau or softening region; 3) non-linear elastic region or re-stretching of the network; 4) lower plateau in which dissociation of some newly made connections occurs. This response is described by a phase transition based continuum model. The model is inspired by the observation of one or more moving interfaces across which densified and rarefied phases of fibers co-exist. I use a quasi-static version of the Abeyaratne-Knowles theory of phase transitions for continua with a stick-slip type kinetic law and a nucleation criterion based on the critical stress for buckling to describe the formation and motion of these interfaces in uniaxial compression experiments. Our models could aid the design of biomaterials and carbon nanotube forests to have desired mechanical properties and guide further understanding of their behavior under large deformations.

Desertification of the peritoneum by thin-film evaporation during laparoscopy.

PubMed

Ott, Douglas E

2003-01-01

To assess the effects of gas flow during insufflation on peritoneal fluid and peritoneal tissue regarding transient thermal behavior and thin-film evaporation. The effects of laparoscopic gas on peritoneal cell desiccation and peritoneal fluid thin-film evaporation were analyzed. Measurment of tissue and peritoneal fluid and analysis of gas flow dynamics during laparoscopy. High-velocity gas interface conditions during laparoscopic gas insufflation result in peritoneal surface temperature and decreases up to 20 degrees C/second due to rapid thin-film evaporation of the peritoneal fluid. Evaporation of the thin film of peritoneal fluid extends quickly to the peritoneal cell membrane, causing peritoneal cell desiccation, internal cytoplasmic stress, and disruption of the cell membrane, resulting in loss of peritoneal surface continuity and integrity. Changing the gas conditions to 35 degrees C and 95% humidity maintains normal peritoneal fluid thin-film characteristics, cellular integrity, and prevents evaporative losses. Cold, dry gas and the characteristics of the laparoscopic gas delivery apparatus cause local peritoneal damaging alterations by high-velocity gas flow with extremely dry gas, creating extreme arid surface conditions, rapid evaporative and hydrological changes, tissue desiccation, and peritoneal fluid alterations that contribute to the process of desertification and thin-film evaporation. Peritoneal desertification is preventable by preconditioning the gas to 35 degrees C and 95% humidity.

Solid and Liquid Waste Drying Bag

NASA Technical Reports Server (NTRS)

Litwiller, Eric (Inventor); Hogan, John A. (Inventor); Fisher, John W. (Inventor)

2009-01-01

Method and system for processing waste from human activities, including solids, liquids and vapors. A fluid-impermeable bag, lined with a liquid-impermeable but vapor-permeable membrane, defining an inner bag, is provided. A vacuum force is provided to extract vapors so that the waste is moved toward a selected region in the inner bag, extracted vapors, including the waste vapors and vaporized portions of the waste liquids are transported across the membrane, and most or all of the solids remain within the liner. Extracted vapors are filtered, and sanitized components thereof are isolated and optionally stored. The solids remaining within the liner are optionally dried and isolated for ultimate disposal.

Enhancing oxygen transport through Mixed-Ionic-and-Electronic-Conducting ceramic membranes

NASA Astrophysics Data System (ADS)

Yu, Anthony S.

Ceramic membranes based on Mixed-Ionic-and-Electronic-Conducting (MIEC) oxides are capable of separating oxygen from air in the presence of an oxygen partial-pressure gradient. These MIEC membranes show great promise for oxygen consuming industrial processes, such as the production of syngas from steam reforming of natural gas (SRM), as well as for electricity generation in Solid Oxide Fuel Cells (SOFC). For both applications, the overall performance is dictated by the rate of oxygen transport across the membrane. Oxygen transport across MIEC membranes is composed of a bulk oxygen-ion diffusion process and surface processes, such as surface reactions and adsorption/desorption of gaseous reactants/products. The main goal of this thesis was to determine which process is rate-limiting in order to significantly enhance the overall rate of oxygen transport in MIEC membrane systems. The rate-limiting step was determined by evaluating the total resistance to oxygen transfer, Rtot. Rtot is the sum of a bulk diffusion resistance in the membrane itself, Rb, and interfacial loss components, Rs. Rb is a function of the membrane's ionic conductivity and thickness, while Rs arises primarily from slow surface-exchange kinetics that cause the P(O2) at the surfaces of the membrane to differ from the P(O 2) in the adjacent gas phases. Rtot can be calculated from the Nernst potential across the membrane and the measured oxygen flux. The rate-limiting process can be determined by evaluating the relative contributions of the various losses, Rs and Rb, to Rtot. Using this method, this thesis demonstrates that for most membrane systems, Rs is the dominating factor. In the development of membrane systems with high oxygen transport rates, thin membranes with high ionic conductivities are required to achieve fast bulk oxygen-ion diffusion. However, as membrane thickness is decreased, surface reaction kinetics become more important in determining the overall transport rate. The two approaches to increase surface reaction kinetics and decrease Rs that were examined in this thesis involved modifying the surface microstructure, as well as adding both metallic (e.g. Pt) and oxide (e.g. CeO2, La0.8Sr0.2FeO3) catalysts to both membrane surfaces. These two approaches were investigated for single-phase MIEC membrane reactors (La0.9Ca0.1FeO3-delta ), as well as composite membrane reactors composed of an electronic conductor (La0.8Sr-0.2CrO3-delta) and an ionic conductor (YSZ). The use of catalysts and microstructure modifications to decrease interfacial losses is equally important for SOFCs. In this thesis, the electrochemical activity and microstructure of metallic catalysts formed by "ex-solving" metals from an oxide lattice, and oxide catalysts deposited by Atomic Layer Deposition (ALD) were investigated. It is shown that these methods for depositing catalysts resulted in very different effects on electrode performance when compared to the same catalysts deposited by wet impregnation. For example, when transition metals, such as Ni and Co, were "ex-solved" from a La0.8Sr0.2CrO3-delta anode lattice, these "ex-solved" metal particles not only exhibited great catalytic activity, they were also less prone to coking compared to their wet impregnated counterparts. On the cathode side, thin layers of various oxides (e.g. Al 2O3, CeOx, SrO) that were deposited using ALD also exhibited drastically different electrochemical activity compared to their wet impregnated counterparts. It was determined that differences in electrochemical activity could be attributed to a difference in the oxide morphology, showing that a catalyst's microstructure and morphology are very important in dictating its overall activity in SOFC electrodes.

Architectured Nanomembranes

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

Sturgeon, Matthew R.; Hu, Michael Z.

2017-07-01

This paper has reviewed the frontier field of “architectured membranes” that contains anisotropic oriented porous nanostructures of inorganic materials. Three example types of architectured membranes were discussed with some relevant results from our own research: (1) anodized thin-layer titania membranes on porous anodized aluminum oxide (AAO) substrates of different pore sizes, (2) porous glass membranes on alumina substrate, and (3) guest-host membranes based on infiltration of yttrium-stabilized zirconia inside the pore channels of AAO matrices.

Electrochemical vapor deposition of semiconductors from gas phase with a solid membrane cell.

PubMed

Cho, Sung Ki; Fan, Fu-Ren F; Bard, Allen J

2015-05-27

We demonstrate the feasibility of semiconductor deposition via the electrochemical reduction of gaseous precursors by the use of an anhydrous proton-conducting membrane, the solid acid CsHSO4, at 165 °C. This membrane electrode assembly was operated within the oxidation of hydrogen on a porous Pt anode and the deposition of Si or Ge under bias at the cathode from chloride-based gaseous precursors; SiCl4 and GeCl4 in an Ar flow with a reduction potential over -1.0 V (vs RHE).

Direct laser writing of micro-supercapacitors on hydrated graphite oxide films.

PubMed

Gao, Wei; Singh, Neelam; Song, Li; Liu, Zheng; Reddy, Arava Leela Mohana; Ci, Lijie; Vajtai, Robert; Zhang, Qing; Wei, Bingqing; Ajayan, Pulickel M

2011-07-31

Microscale supercapacitors provide an important complement to batteries in a variety of applications, including portable electronics. Although they can be manufactured using a number of printing and lithography techniques, continued improvements in cost, scalability and form factor are required to realize their full potential. Here, we demonstrate the scalable fabrication of a new type of all-carbon, monolithic supercapacitor by laser reduction and patterning of graphite oxide films. We pattern both in-plane and conventional electrodes consisting of reduced graphite oxide with micrometre resolution, between which graphite oxide serves as a solid electrolyte. The substantial amounts of trapped water in the graphite oxide makes it simultaneously a good ionic conductor and an electrical insulator, allowing it to serve as both an electrolyte and an electrode separator with ion transport characteristics similar to that observed for Nafion membranes. The resulting micro-supercapacitor devices show good cyclic stability, and energy storage capacities comparable to existing thin-film supercapacitors.

Direct laser writing of micro-supercapacitors on hydrated graphite oxide films

NASA Astrophysics Data System (ADS)

Gao, Wei; Singh, Neelam; Song, Li; Liu, Zheng; Reddy, Arava Leela Mohana; Ci, Lijie; Vajtai, Robert; Zhang, Qing; Wei, Bingqing; Ajayan, Pulickel M.

2011-08-01

Microscale supercapacitors provide an important complement to batteries in a variety of applications, including portable electronics. Although they can be manufactured using a number of printing and lithography techniques, continued improvements in cost, scalability and form factor are required to realize their full potential. Here, we demonstrate the scalable fabrication of a new type of all-carbon, monolithic supercapacitor by laser reduction and patterning of graphite oxide films. We pattern both in-plane and conventional electrodes consisting of reduced graphite oxide with micrometre resolution, between which graphite oxide serves as a solid electrolyte. The substantial amounts of trapped water in the graphite oxide makes it simultaneously a good ionic conductor and an electrical insulator, allowing it to serve as both an electrolyte and an electrode separator with ion transport characteristics similar to that observed for Nafion membranes. The resulting micro-supercapacitor devices show good cyclic stability, and energy storage capacities comparable to existing thin-film supercapacitors.

Constitutive Models for the Viscoelastic Behavior of Polyimide Membranes at Room and Deep Cryogenic Temperatures

DOE PAGES

Bhandarkar, Suhas; Betcher, Jacob; Smith, Ryan; ...

2016-06-30

Targets for ICF shots on NIF typically use ~500nm thin polyimide films with a coating of 25nm of aluminum as windows that seal the laser entrance hole or LEH. Their role is to contain the hohlraum gas and minimize the extraneous infra-red radiation getting in. This is necessary to precisely control the hohlraum thermal environment for layering inside the capsule with solid deuterium-tritium at 18K. Here, we use our empirical data on the bulging behavior of these foils under various different conditions to develop models to capture the complex viscoelastic behavior of these films at both ambient and cryogenic temperatures.more » The constitutive equations derived from these models give us the ability to quantitatively specify the film’s behavior during the fielding of these targets and set the best parameters for new target designs.« less

Specific heat measurement set-up for quench condensed thin superconducting films.

PubMed

Poran, Shachaf; Molina-Ruiz, Manel; Gérardin, Anne; Frydman, Aviad; Bourgeois, Olivier

2014-05-01

We present a set-up designed for the measurement of specific heat of very thin or ultra-thin quench condensed superconducting films. In an ultra-high vacuum chamber, materials of interest can be thermally evaporated directly on a silicon membrane regulated in temperature from 1.4 K to 10 K. On this membrane, a heater and a thermometer are lithographically fabricated, allowing the measurement of heat capacity of the quench condensed layers. This apparatus permits the simultaneous thermal and electrical characterization of successively deposited layers in situ without exposing the deposited materials to room temperature or atmospheric conditions, both being irreversibly harmful to the samples. This system can be used to study specific heat signatures of phase transitions through the superconductor to insulator transition of quench condensed films.

Highly-efficient forward osmosis membrane tailored by magnetically responsive graphene oxide/Fe3O4 nanohybrid

NASA Astrophysics Data System (ADS)

Rastgar, Masoud; Shakeri, Alireza; Bozorg, Ali; Salehi, Hasan; Saadattalab, Vahid

2018-05-01

Emerging forward osmosis (FO) process as a potentially more energy efficient method has recently gained remarkable attention. Herein, considering the unique features of graphene oxide (GO), a new facile method has been proposed to magnetically modify GO within the polyamide active layer to obtain highly efficient osmotically driven membranes. While exposed to magnetic field, thin film nanocomposite membranes modified by GO/Fe3O4 nanohybrids (TFN-MMGO/Fe3O4) were synthesized by in-situ interfacial polymerization of the prepared monomer solution and organic trimesoyl chloride. Water permeability, salt rejection, and fouling tendency of the modified membranes were then evaluated and compared with both pristine thin film composite (TFC) membrane and the ones modified by GO/Fe3O4 nanohybrides in the absence of magnetic field (TFN-GO/Fe3O4). According to the experimental results, when compared to the TFC and TFN-GO/Fe3O4 membranes, respectively, 117.4% and 63.2% water flux enhancements were achieved in TFN-MMGO/Fe3O4 membrane with optimal GO/Fe3O4 nanohybrid concentration of 100 ppm. In spite of such improvements in water flux, little compromise in reverse salt leakages were observed in the TFN-MMGO/Fe3O4 membranes compared to the TFC one. As well, the TFN-MMGO/Fe3O4 and TFN-GO/Fe3O4 membranes revealed higher fouling resistances than the TFC membrane due to their distinguished manipulated surface characteristics.

Preparation of redox polymer cathodes for thin film rechargeable batteries

DOEpatents

Skotheim, T.A.; Lee, H.S.; Okamoto, Yoshiyuki.

1994-11-08

The present invention relates to the manufacture of thin film solid state electrochemical devices using composite cathodes comprising a redox polymer capable of undergoing oxidation and reduction, a polymer solid electrolyte and conducting carbon. The polymeric cathode material is formed as a composite of radiation crosslinked polymer electrolytes and radiation crosslinked redox polymers based on polysiloxane backbones with attached organosulfur side groups capable of forming sulfur-sulfur bonds during electrochemical oxidation.

The study of effect of solid electrolyte on charge-discharge characteristics of thin-film lithium-ion batteries

NASA Astrophysics Data System (ADS)

Mazaletskiy, L. A.; Lebedev, M. E.; Mironenko, A. A.; Naumov, V. V.; Novozhilova, A. V.; Fedorov, I. S.; Rudy, A. S.

2017-11-01

Results of studies of the solid electrolyte effect on capacitance of thin-film electrodes on the basis of Si-O-Al and VxOy nanocomposites are presented. The studies were carried out by comparing the charge-discharge characteristics of two pairs of the identical electrodes, one of which was covered by LiPON film, within prototypes with two lithium electrodes - the counter and the reference electrode.

Buckling of thin walled composite cylindrical shell filled with solid propellant

NASA Astrophysics Data System (ADS)

Dash, A. P.; Velmurugan, R.; Prasad, M. S. R.

2017-12-01

This paper investigates the buckling of thin walled composite cylindrical tubes that are partially filled with solid propellant equivalent elastic filler. Experimental investigation is conducted on thin composite tubes made out of S2-glass epoxy, which is made by using filament winding technique. The composite tubes are filled with elastic filler having similar mechanical properties as that of a typical solid propellant used in rocket motors. The tubes are tested for their buckling strength against the external pressure in the presence of the filler. Experimental data confirms the enhancement of external pressure carrying capacity of the composite tubes by up to three times as that of empty tubes for a volumetric loading fraction (VLF) of 0.9. Furthermore, the finite element based geometric nonlinearity analysis predicts the buckling behaviour of the partially filled composite tubes close to the experimental results.

Templated Solid-State Dewetting of Thin Silicon Films.

PubMed

Naffouti, Meher; David, Thomas; Benkouider, Abdelmalek; Favre, Luc; Delobbe, Anne; Ronda, Antoine; Berbezier, Isabelle; Abbarchi, Marco

2016-11-01

Thin film dewetting can be efficiently exploited for the implementation of functionalized surfaces over very large scales. Although the formation of sub-micrometer sized crystals via solid-state dewetting represents a viable method for the fabrication of quantum dots and optical meta-surfaces, there are several limitations related to the intrinsic features of dewetting in a crystalline medium. Disordered spatial organization, size, and shape fluctuations are relevant issues not properly addressed so far. This study reports on the deterministic nucleation and precise positioning of Si- and SiGe-based nanocrystals by templated solid-state dewetting of thin silicon films. The dewetting dynamics is guided by pattern size and shape taking full control over number, size, shape, and relative position of the particles (islands dimensions and relative distances are in the hundreds nm range and fluctuate ≈11% for the volumes and ≈5% for the positioning). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Controllable light filters using an all-solid-state switchable mirror with a Mg-Ir thin film for preterm infant incubators

NASA Astrophysics Data System (ADS)

Tajima, Kazuki; Shimoike, Mika; Li, Heng; Inagaki, Masumi; Izumi, Hitomi; Akiyama, Misaki; Matsushima, Yukiko; Ohta, Hidenobu

2013-04-01

We have fabricated a controllable light filter using an all-solid-state switchable mirror incorporating a Mg-Ir thin film for use in preterm infant incubators. The solid-state switchable mirror device was fabricated by depositing a multilayer on a glass substrate. The mixed hydride of MgH2 and Mg6Ir2H11 created from the Mg-Ir thin film is red in the transparent state. The optical switching speeds between the reflective and transparent red states depended on applied voltage. The device showed three states, namely, reflective, black, and transparent red, due to the properties of the switchable mirror material. These results suggest that the material could be used as a controllable light filter for preterm infant incubators, since it eliminates the light wavelength that disturbs regular sleep-wake cycles of preterm infants.

Oxygen separation from air using zirconia solid electrolyte membranes

NASA Technical Reports Server (NTRS)

Suitor, J. W.; Marner, W. J.; Schroeder, J. E.; Losey, R. W.; Ferrall, J. F.

1988-01-01

Air separation using a zirconia solid electrolyte membrane is a possible alternative source of oxygen. The process of zirconia oxygen separation is reviewed, and an oxygen plant concept using such separation is described. Potential cell designs, stack designs, and testing procedures are examined. Fabrication of the materials used in a zirconia module as well as distribution plate design and fabrication are examined.

Acute epidural-like appearance of an encapsulated solid non-organized chronic subdural hematoma.

PubMed

Prieto, Ruth; Pascual, José M; Subhi-Issa, Issa; Yus, Miguel

2010-01-01

We report the exceptional case of an encapsulated solid non-organized chronic subdural hematoma (SDH) in a 67-year-old woman that was admitted with acute hemiplegia followed by rapid deterioration in consciousness 5 months after a minor head trauma. Computed tomography (CT) showed an extracerebral biconvex shaped hyperdense mass that led to the misdiagnosis of an acute epidural hematoma. Urgent craniotomy revealed an encapsulated mass filled with solid fresh clot in the subdural space. Complete evacuation of this SDH, including both its inner and outer membranes, was achieved, and the patient recovered successfully. Histological analysis confirmed that the content of the hematoma corresponded to a newly formed clot that was enclosed between an inner membrane, composed of two collagen layers, and an outer membrane with a three layered structure. Chronic SDH may seldom present as an encapsulated solid non-organized lesion that consists of a fibrous capsule enclosing a fresh clot and lacking the thick fibrous septations that typically connect the inner and outer membranes of organized chronic SDH. This entity mimics the clinical course and radiological appearance of acute epidural hematomas and should be considered in the differential diagnosis of extracerebral hyperdense biconvex shaped lesions.

Validating the technological feasibility of yttria-stabilized zirconia-based semiconducting-ionic composite in intermediate-temperature solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Cai, Yixiao; Wang, Baoyuan; Wang, Yi; Xia, Chen; Qiao, Jinli; van Aken, Peter A.; Zhu, Bin; Lund, Peter

2018-04-01

YSZ as the electrolyte of choice has dominated the progressive development of solid oxide fuel cell (SOFC) technologies for many years. To enable SOFCs operating at intermediate temperatures of 600 °C or below, major technical advances were built on a foundation of a thin-film YSZ electrolyte, NiO anode, and perovskite cathode, e.g. La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF). Inspired by functionalities in engineered heterostructure interfaces, the present work uses the components from state-of-the-art SOFCs, i.e, the anode NiO-YSZ and the cathode LSCF-YSZ, or the convergence of all three components, i.e., NiO-YSZ-LSCF, to fabricate semiconductor-ionic membranes (SIMs) and devices. A series of proof-of-concept fuel cell devices are designed by using each of the above SIMs sandwiched between two semiconducting Ni0.8Co0.15Al0.05LiO2-δ (NCAL) layers. We systematically compare these novel designs at 600 °C with two reference fuel cells: a commercial product of anode-supported YSZ electrolyte thin-film cell, and a lab-assembled fuel cell with a conventional configuration of NiO-YSZ (anode)/YSZ (electrolyte)/LSCF-YSZ (cathode). In comparison to the reference cells, the SIM device in a configuration of NCAL/NiO-YSZ-LSCF/NCAL reaches more than 3-fold enhancement of the maximum power output. By using spherical aberration-corrected transmission electron microscopy and spectroscopy approaches, this work offers insight into the mechanisms underlying SIM-associated SOFC performance enhancement.

Neutron Reflectivity as a Tool for Physics-Based Studies of Model Bacterial Membranes.

PubMed

Barker, Robert D; McKinley, Laura E; Titmuss, Simon

2016-01-01

The principles of neutron reflectivity and its application as a tool to provide structural information at the (sub-) molecular unit length scale from models for bacterial membranes are described. The model membranes can take the form of a monolayer for a single leaflet spread at the air/water interface, or bilayers of increasing complexity at the solid/liquid interface. Solid-supported bilayers constrain the bilayer to 2D but can be used to characterize interactions with antimicrobial peptides and benchmark high throughput lab-based techniques. Floating bilayers allow for membrane fluctuations, making the phase behaviour more representative of native membranes. Bilayers of varying levels of compositional accuracy can now be constructed, facilitating studies with aims that range from characterizing the fundamental physical interactions, through to the characterization of accurate mimetics for the inner and outer membranes of Gram-negative bacteria. Studies of the interactions of antimicrobial peptides with monolayer and bilayer models for the inner and outer membranes have revealed information about the molecular control of the outer membrane permeability, and the mode of interaction of antimicrobials with both inner and outer membranes.

Liquid membrane coated ion-exchange column solids

DOEpatents

Barkey, Dale P.

1988-01-01

This invention relates to a method for improving the performance of liquid membrane separations by coating a liquid membrane onto solid ion-exchange resin beads in a fixed bed. Ion-exchange beads fabricated from an ion-exchange resin are swelled with water and are coated with a liquid membrane material that forms a film over the beads. The beads constitute a fixed bed ion-exchange column. Fluid being treated that contains the desired ion to be trapped by the ion-exchange particle is passed through the column. A carrier molecule, contained in the liquid membrane ion-exchange material, is selective for the desired ion in the fluid. The carrier molecule forms a complex with the desired ion, transporting it through the membrane and thus separating it from the other ions. The solution is fed continuously until breakthrough occurs at which time the ion is recovered, and the bed is regenerated.

Molecular transport through nanoporous silicon nitride membranes produced from self-assembling block copolymers.

PubMed

Montagne, Franck; Blondiaux, Nicolas; Bojko, Alexandre; Pugin, Raphaël

2012-09-28

To achieve fast and selective molecular filtration, membrane materials must ideally exhibit a thin porous skin and a high density of pores with a narrow size distribution. Here, we report the fabrication of nanoporous silicon nitride membranes (NSiMs) at the full wafer scale using a versatile process combining block copolymer (BCP) self-assembly and conventional photolithography/etching techniques. In our method, self-assembled BCP micelles are used as templates for creating sub-100 nm nanopores in a thin low-stress silicon nitride layer, which is then released from the underlying silicon wafer by etching. The process yields 100 nm thick free-standing NSiMs of various lateral dimensions (up to a few mm(2)). We show that the membranes exhibit a high pore density, while still retaining excellent mechanical strength. Permeation experiments reveal that the molecular transport rate across NSiMs is up to 16-fold faster than that of commercial polymeric membranes. Moreover, using dextran molecules of various molecular weights, we also demonstrate that size-based separation can be achieved with a very good selectivity. These new silicon nanosieves offer a relevant technological alternative to commercially available ultra- and microfiltration membranes for conducting high resolution biomolecular separations at small scales.

Fabrication of hydrophobic fluorinated silica-polyamide thin film nanocomposite reverse osmosis membranes with dramatically improved salt rejection.

PubMed

Pang, Ruizhi; Zhang, Kaisong

2018-01-15

Thin film nanocomposite reverse osmosis (TFN RO) membranes incorporated with hydrophilic nanoparticles show a potential problem that the salt rejection can not be improved significantly. In this study, novel TFN RO membranes incorporated with hydrophobic fluorinated silica nanoparticles were fabricated to improve the salt rejection. Fluorinated silica nanoparticles were well dispersed in organic phase during the interfacial polymerization (IP) process. The TFN RO membranes were characterized with attenuated total reflectance infra-red, field emission scanning electron microscopy, atomic force microscopy and water contact angle measurements. The preparation conditions of TFN RO membranes, including IP reaction time, organic solvent removal time, and fluorinated silica loading, were optimized by characterizing desalination performance using 2000ppm NaCl aqueous solution at 1.55MPa and 25°C. The salt rejection increased significantly from 96.0% without fluorinated silica nanoparticles to 98.6% with the optimal 0.12% (w/v) fluorinated silica nanoparticles, while the water flux decreased slightly from 0.99m 3 /m 2 /day to 0.93m 3 /m 2 /day. This study demonstrated the potential use of hydrophobic nanoparticles in high-performance TFN RO membranes. Copyright © 2017 Elsevier Inc. All rights reserved.

Tunable-Porosity Membranes From Discrete Nanoparticles

PubMed Central

Marchetti, Patrizia; Mechelhoff, Martin; Livingston, Andrew G.

2015-01-01

Thin film composite membranes were prepared through a facile single-step wire-wound rod coating procedure in which internally crosslinked poly(styrene-co-butadiene) polymer nanoparticles self-assembled to form a thin film on a hydrophilic ultrafiltration support. This nanoparticle film provided a defect-free separation layer 130–150 nm thick, which was highly permeable and able to withstand aggressive pH conditions beyond the range of available commercial membranes. The nanoparticles were found to coalesce to form a rubbery film when heated above their glass transition temperature (Tg). The retention properties of the novel membrane were strongly affected by charge repulsion, due to the negative charge of the hydroxyl functionalized nanoparticles. Porosity was tuned by annealing the membranes at different temperatures, below and above the nanoparticle Tg. This enabled fabrication of membranes with varying performance. Nanofiltration properties were achieved with a molecular weight cut-off below 500 g mol−1 and a low fouling tendency. Interestingly, after annealing above Tg, memory of the interstitial spaces between the nanoparticles persisted. This memory led to significant water permeance, in marked contrast to the almost impermeable films cast from a solution of the same polymer. PMID:26626565

High density group IV semiconductor nanowire arrays fabricated in nanoporous alumina templates

NASA Astrophysics Data System (ADS)

Redwing, Joan M.; Dilts, Sarah M.; Lew, Kok-Keong; Cranmer, Alexana E.; Mohney, Suzanne E.

2005-11-01

The fabrication of high density arrays of semiconductor nanowires is of interest for nanoscale electronics, chemical and biological sensing and energy conversion applications. We have investigated the synthesis, intentional doping and electrical characterization of Si and Ge nanowires grown by the vapor-liquid-solid (VLS) method in nanoporous alumina membranes. Nanoporous membranes provide a convenient platform for nanowire growth and processing, enabling control of wire diameter via pore size and the integration of contact metals for electrical testing. For VLS growth in nanoporous materials, reduced pressures and temperatures are required in order to promote the diffusion of reactants into the pore without premature decomposition on the membrane surface or pore walls. The effect of growth conditions on the growth rate of Si and Ge nanowires from SiH 4 and GeH 4 sources, respectively, was investigated and compared. In both cases, the measured activation energies for nanowire growth were substantially lower than activation energies typically reported for Si and Ge thin film deposition under similar growth conditions, suggesting that gold plays a catalytic role in the VLS growth process. Intentionally doped SiNW arrays were also prepared using trimethylboron (TMB) and phosphine (PH 3) as p-type and n-type dopant sources, respectively. Nanowire resistivities were calculated from plots of the array resistance as a function of nanowire length. A decrease in resistivity was observed for both n-type and p-type doped SiNW arrays compared to those grown without the addition of a dopant source.

Bacterial cellulose membrane as separation medium

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

Shibazaki, Hideki; Kuga, Shigenori; Onabe, Fumihiko

1993-11-10

A thin membrane of bacterial cellulose (BC) obtained from Acetobacter culture was tested for its performance as a dialysis membrane in aqueous systems. The BC membrane showed superior mechanical strength to that of a dialysis-grade regenerated cellulose membrane, allowing the use of a thinner membrane than the latter. As a result, the BC membrane gave higher permeation rates for poly(ethylene glycols) as probe solutes. The cutoff molecular weight of the original BC membrane, significantly greater than that of regenerated cellulose, could be modified by concentrated alkali treatments of the membrane. The nature of the change at the ultrastructural level causedmore » by the alkali treatments was studied by X-ray diffraction and scanning electron microscopy.« less

Elaboration and characterization of a free standing LiSICON membrane for aqueous lithium-air battery

NASA Astrophysics Data System (ADS)

Puech, Laurent; Cantau, Christophe; Vinatier, Philippe; Toussaint, Gwenaëlle; Stevens, Philippe

2012-09-01

In order to develop a LISICON separator for an aqueous lithium-air battery, a thin membrane was prepared by a tape-casting of a Li1.3Al0.3Ti1.7 (PO4)3-AlPO4 based slip followed by a sintering step. By optimizing the grain sizes, the slip composition and the sintering treatment, the mechanical properties were improved and the membrane was reduced to a thickness of down to 40 μm. As a result, the ionic resistance is relatively low, around 38 Ω for a 55 μm membrane of 1 cm2. One side of the membrane was coated with a lithium oxynitrured phosphorous (LiPON) thin film to prevent lithium metal attack. Lithium metal was electrochemically deposited on the LiPON surface from a saturated aqueous solution of LiOH. However, the ionic resistance of the LiPON film, around 67 Ω for a 1.2 μm film of 1 cm2, still causes an important ohmic loss contribution which limits the power performance of a lithium-air battery.

Technical advisory guide (TAG) for bonded wearing course pilot projects.

DOT National Transportation Integrated Search

2003-10-01

A bonded wearing course (BWC) is a gap graded, ultra thin hot-mix asphalt (HMA) mixture applied : over a thick polymer modified asphalt emulsion membrane. The emulsion membrane seals the : existing surface and produces high binder content at the inte...

Demulsification of water/oil/solid emulsions by hollow-fiber membranes

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

Tirmizi, N.P.; Raghuraman, B.; Wiencek, J.

1996-05-01

The demulsification techniques investigated use preferential surface wetting to allow separation of oil and water phases in ultrafiltration and microfiltration membranes. A hydrophobic membrane allows the permeation of an oil phase at almost zero pressure and retains the water phase, even though the molecular weight of the water molecule (18) is much smaller than that of the oil molecule (198 for tetradecane, used in this study). Hydrophobic membranes having pore sizes from 0.02 to 0.2 {micro}m were tested for demulsification of water-in-oil emulsions and water/oil/solid mixtures. The dispersed (aqueous)-phase drop sizes ranged from 1 to 5 {micro}m. High separation rates,more » as well as good permeate quality, were obtained with microfiltration membranes. Water content of permeating oil was 32--830 ppm depending on operating conditions and interfacial properties. For emulsions with high surfactant content, simultaneous operation of a hydrophobic and hydrophilic membrane, or simultaneous membrane separation with electric demulsification was more efficient in obtaining complete phase separation.« less

A fully spray-coated fuel cell membrane electrode assembly using Aquivion ionomer with a graphene oxide/cerium oxide interlayer

NASA Astrophysics Data System (ADS)

Breitwieser, Matthias; Bayer, Thomas; Büchler, Andreas; Zengerle, Roland; Lyth, Stephen M.; Thiele, Simon

2017-05-01

A novel multilayer membrane electrode assembly (MEA) for polymer electrolyte membrane fuel cells (PEMFCs) is fabricated in this work, within a single spray-coating device. For the first time, direct membrane deposition is used to fabricate a PEMFC by spraying the short-side-chain ionomer Aquivion directly onto the gas diffusion electrodes. The fully sprayed MEA, with an Aquivion membrane 10 μm in thickness, achieved a high power density of 1.6 W/cm2 for H2/air operation at 300 kPaabs. This is one of the highest reported values for thin composite membranes operated in H2/air atmosphere. By the means of confocal laser scanning microscopy, individual carbon fibers from the gas diffusion layer are identified to penetrate through the micro porous layer (MPL), likely causing a low electrical cell resistance in the range of 150 Ω cm2 through the thin sprayed membranes. By spraying a 200 nm graphene oxide/cerium oxide (GO/CeO2) interlayer between two layers of Aquivion ionomer, the impact of the electrical short is eliminated and the hydrogen crossover current density is reduced to about 1 mA/cm2. The peak power density of the interlayer-containing MEA drops only by 10% compared to a pure Aquivion membrane of similar thickness.

Selective Permeating Properties of Butanol and Water through Polystyrene- b-polydimethylsiloxane- b-polystyrene Pervaporation Membranes

NASA Astrophysics Data System (ADS)

Shin, Chaeyoung; Baer, Zachary; Chen, X. Chelsea; Ozcam, A. Evren; Clark, Douglas; Balsara, Nitash

2015-03-01

Polystyrene- b-polydimethylsiloxane- b-polystyrene (SDS) membranes have been studied in butanol-water binary pervaporation experiments and pervaporation experiments integrated with viable fermentation broths. Polydimethylsiloxane has been widely known to be a suitable material for separating organic chemicals from aqueous solutions, and it thus provides a continuous matrix phase in SDS membranes for permeation of small molecules. The polystyrene block provides mechanical stability to maintain the membrane structure in the pervaporation membranes. We take advantage of these features to fabricate a thin and butanol-selective SDS membrane for in situ product removal in fermentation.

Application of graphene oxide in water treatment

NASA Astrophysics Data System (ADS)

Liu, Yongchen

2017-11-01

Graphene oxide has good hydrophilicity and has been tried to use it into thin films for water treatment in recent years. In this paper, the preparation methods of graphene oxide membrane are reviewed, including vacuum suction filtration, spray coating, spin coating, dip coating and the layer by layer method. Secondly, the mechanism of mass transfer of graphene membrane is introduced in detail. The application of the graphene oxide membrane, modified graphene oxide membrane and graphene hybrid membranes were discussed in RO, vaporization, nanofiltration and other aspects. Finally, the development and application of graphene membrane in water treatment were discussed.

Microfabrication of hybrid fluid membrane for microengines

NASA Astrophysics Data System (ADS)

Chutani, R.; Formosa, F.; de Labachelerie, M.; Badel, A.; Lanzetta, F.

2015-12-01

This paper describes the microfabrication and dynamic characterization of thick membranes providing a technological solution for microengines. The studied membranes are called hybrid fluid-membrane (HFM) and consist of two thin membranes that encapsulate an incompressible fluid. This work details the microelectromechanical system (MEMS) scalable fabrication and characterization of HFMs. The membranes are composite structures based on Silicon spiral springs embedded in a polymer (RTV silicone). The anodic bonding of multiple stacks of Si/glass structures, the fluid filling and the sealing have been demonstrated. Various HFMs were successfully fabricated and their dynamic characterization demonstrates the agreement between experimental and theoretical results.

Ion-Selective Electrodes.

ERIC Educational Resources Information Center

Arnold, Mark A.; Meyerhoff, Mark E.

1984-01-01

Literature on ion-selective electrodes (ISEs) is reviewed in seven sections: books, conferences, reviews; potentiometric membrane electrodes; glass and solid-state membrane electrodes; liquid and polymer membrane ISEs; coated wire electrodes, ion-selective field effect transistors, and microelectrodes; gas sensors and selective bioelectrode…

Direct liquid-feed fuel cell with membrane electrolyte and manufacturing thereof

NASA Technical Reports Server (NTRS)

Narayanan, Sekharipuram (Inventor); Surampudi, Subbarao (Inventor); Halpert, Gerald (Inventor)

1999-01-01

An improved direct liquid-feed fuel cell having a solid membrane electrolyte for electrochemical reactions of an organic fuel. Improvements in interfacing of the catalyst layer and the membrane and activating catalyst materials are disclosed.

Numerical Computation of Flame Spread over a Thin Solid in Forced Concurrent Flow with Gas-phase Radiation

NASA Technical Reports Server (NTRS)

Jiang, Ching-Biau; T'ien, James S.

1994-01-01

Excerpts from a paper describing the numerical examination of concurrent-flow flame spread over a thin solid in purely forced flow with gas-phase radiation are presented. The computational model solves the two-dimensional, elliptic, steady, and laminar conservation equations for mass, momentum, energy, and chemical species. Gas-phase combustion is modeled via a one-step, second order finite rate Arrhenius reaction. Gas-phase radiation considering gray non-scattering medium is solved by a S-N discrete ordinates method. A simplified solid phase treatment assumes a zeroth order pyrolysis relation and includes radiative interaction between the surface and the gas phase.

Parasitic oscillation suppression in solid state lasers using absorbing thin films

DOEpatents

Zapata, L.E.

1994-08-02

A thin absorbing film is bonded onto at least certain surfaces of a solid state laser gain medium. An absorbing metal-dielectric multilayer film is optimized for a broad range of incidence angles, and is resistant to the corrosive/erosive effects of a coolant such as water, used in the forced convection cooling of the film. Parasitic oscillations hamper the operation of solid state lasers by causing the decay of stored energy to amplified rays trapped within the gain medium by total and partial internal reflections off the gain medium facets. Zigzag lasers intended for high average power operation require the ASE absorber. 16 figs.

Solid-state dewetting of thin Au films studied with real-time, in situ spectroscopic ellipsometry

NASA Astrophysics Data System (ADS)

Magnozzi, M.; Bisio, F.; Canepa, M.

2017-11-01

We report the design and testing of a small, high vacuum chamber that allows real-time, in situ spectroscopic ellipsometry (SE) measurements; the chamber was designed to be easily inserted within the arms of a commercial ellipsometer. As a test application, we investigated the temperature-induced solid-state dewetting of thin (20 to 8 nm) Au layers on Si wafers. In situ SE measurements acquired in real time during the heating of the samples reveal features that can be related to the birth of a localized surface plasmon resonance (LSPR), and demonstrate the presence of a temperature threshold for the solid-state dewetting.

Parasitic oscillation suppression in solid state lasers using absorbing thin films

DOEpatents

Zapata, Luis E.

1994-01-01

A thin absorbing film is bonded onto at least certain surfaces of a solid state laser gain medium. An absorbing metal-dielectric multilayer film is optimized for a broad range of incidence angles, and is resistant to the corrosive/erosive effects of a coolant such as water, used in the forced convection cooling of the film. Parasitic oscillations hamper the operation of solid state lasers by causing the decay of stored energy to amplified rays trapped within the gain medium by total and partial internal reflections off the gain medium facets. Zigzag lasers intended for high average power operation require the ASE absorber.

The Formation and Properties of Thin Lipid Membranes from HK and LK Sheep Red Cell Lipids

PubMed Central

Andreoli, Thomas E.; Bangham, J. Andrew; Tosteson, Daniel C.

1967-01-01

Lipids were obtained from high potassium (HK) and low potassium (LK) sheep red cells by sequential extraction of the erythrocytes with isopropanol-chloroform, chloroform-methanol-0.1 M KCl, and chloroform. The extract contained cholesterol and phospholipid in a molar ratio of 0.8:1.0, and less than 1% protein contaminant. Stable thin lipid membranes separating two aqueous compartments were formed from an erythrocyte lipid-hydrocarbon solution, and had an electrical resistance of ∼108 ohm-cm2 and a capacitance of 0.38–0.4 µf/cm2. From the capacitance values, membrane thickness was estimated to be 46–132 A, depending on the assumed value for the dielectric constant (2.0–4.5). Membrane voltage was recorded in the presence of ionic (NaCl and/or KCl) concentration gradients in the solutions bathing the membrane. The permeability of the membrane to Na+, K+, and Cl- (expressed as the transference number, T ion) was computed from the steady-state membrane voltage and the activity ratio of the ions in the compartments bathing the membrane. T Na and T K were approximately equal (∼0.8) and considerably greater than T Cl (∼0.2). The ionic transference numbers were independent of temperature, the hydrocarbon solvent, the osmolarity of the solutions bathing the membranes, and the cholesterol content of the membranes, over the range 21–38°C. The high degree of membrane cation selectivity was tentatively attributed to the negatively charged phospholipids (phosphatidylethanolamine and phosphatidylserine) present in the lipid extract. PMID:6034765

40 CFR 240.101 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... pollutants released to the atmosphere. (g) Facility means all thermal processing equipment, buildings, and... hazards by spreading the solid wastes in thin layers, compacting the solid wastes to the smallest...

40 CFR 240.101 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... pollutants released to the atmosphere. (g) Facility means all thermal processing equipment, buildings, and... hazards by spreading the solid wastes in thin layers, compacting the solid wastes to the smallest...

40 CFR 240.101 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... pollutants released to the atmosphere. (g) Facility means all thermal processing equipment, buildings, and... hazards by spreading the solid wastes in thin layers, compacting the solid wastes to the smallest...

Hydraulically amplified PZT mems actuator

DOEpatents

Miles, Robin R.

2004-11-02

A hydraulically amplified microelectromechanical systems actuator. A piece of piezoelectric material or stacked piezo bimorph is bonded or deposited as a thin film. The piece is operatively connected to a primary membrane. A reservoir is operatively connected to the primary membrane. The reservoir contains a fluid. A membrane is operatively connected to the reservoir. In operation, energizing the piezoelectric material causing the piezoelectric material to bow. Bowing of the piezoelectric material causes movement of the primary membrane. Movement of the primary membrane results in a force in being transmitted to the liquid in the reservoir. The force in the liquid causes movement of the membrane. Movement of the membrane results in an operating actuator.

Solid-phase receptor binding assay for /sup 125/I-hCG

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

Bortolussi, M.; Selmin, O.; Colombatti, A.

1987-01-01

A solid-phase radioligand-receptor assay (RRA) to measure the binding of /sup 125/I-labelled human chorionic gonadotropin (/sup 125/I-hCG) to target cell membranes has been developed. The binding of /sup 125/I-hCG to membranes immobilized on the wells of microtitration plates reached a maximum at about 3 hours at 37 degrees C, was saturable, displayed a high affinity (Ka = 2.4 X 10(9) M-1) and was specifically inhibited by unlabelled hCG. In comparison with RRAs carried out with membranes in suspension, the solid-phase RRA is significantly simpler and much faster to perform as it avoids centrifugation or filtration procedures. The solid-phase RRA wasmore » adapted profitably to process large numbers of samples at the same time. It proved particularly useful as a screening assay to detect anti-hCG monoclonal antibodies with high inhibitory activity for binding of /sup 125/I-hCG to its receptors.« less

Investigation of Rhodopsin Dynamics in its Signaling State by Solid-State Deuterium NMR Spectroscopy

PubMed Central

Struts, Andrey V.; Chawla, Udeep; Perera, Suchithranga M.D.C.; Brown, Michael F.

2017-01-01

Site-directed deuterium NMR spectroscopy is a valuable tool to study the structural dynamics of biomolecules in cases where solution NMR is inapplicable. Solid-state 2H NMR spectral studies of aligned membrane samples of rhodopsin with selectively labeled retinal provide information on structural changes of the chromophore in different protein states. In addition, solid-state 2H NMR relaxation time measurements allow one to study the dynamics of the ligand during the transition from the inactive to the active state. Here we describe the methodological aspects of solid-state 2H NMR spectroscopy for functional studies of rhodopsin, with an emphasis on the dynamics of the retinal cofactor. We provide complete protocols for the preparation of NMR samples of rhodopsin with 11-cis-retinal selectively deuterated at the methyl groups in aligned membranes. In addition, we review optimized conditions for trapping the rhodopsin photointermediates; and lastly we address the challenging problem of trapping the signaling state of rhodopsin in aligned membrane films. PMID:25697522

Study on submerged anaerobic membrane bioreactor (SAMBR) treating high suspended solids raw tannery wastewater for biogas production.

PubMed

Umaiyakunjaram, R; Shanmugam, P

2016-09-01

This study deals with the treatment of high suspended solids raw tannery wastewater using flat sheet Submerged Anaerobic Membrane (0.4μm) Bioreactor (SAMBR) acclimatized with hypersaline anaerobic seed sludge for recovering biogas. The treatability of SAMBR achieved higher CODremoval efficiency (90%) and biogas yield (0.160L.g(-1) CODremoved) coincided with high r(2) values between permeate flux and TSS (0.95), biogas and COD removed (0.96). The acidification of hypersaline influent wastewater by biogas mixing with high CO2, achieved quadruplet benefit of gas liquid and solid separation, in-situ pH and NH3 control, in-situ CH4 enrichment, and prevention of membrane fouling. The initial high VFA became stable as time elapsed reveals the hydrolysing ability of particulate COD into soluble COD and into biogas, confirms the suitability of SAMBR for high suspended solids tannery wastewater. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fuel cell ion-exchange membrane investigation

NASA Technical Reports Server (NTRS)

Toy, M. S.

1972-01-01

The present deficiencies in the fluorocarbon sulfonic acid membrane used as the solid polymer electrolyte in the H2/O2 fuel cell are studied. Considered are: Adhesives selection, elastomeric formulations, scavenger exploration, and membrane characterization. The significant data are interpreted and recommendations are given for both short and long range further investigations in two of the four major areas: membrane adhesives and membrane stabilization.

Experimental validation of damping properties and solar pressure effects on flexible, high area-to-mass ratio debris model

NASA Astrophysics Data System (ADS)

Channumsin, Sittiporn; Ceriotti, Matteo; Radice, Gianmarco; Watson, Ian

2017-09-01

Multilayer insulation (MLI) is a recently-discovered type of debris originating from delamination of aging spacecraft; it is mostly detected near the geosynchronous orbit (GEO). Observation data indicates that these objects are characterised by high reflectivity, high area-to-mass ratio (HAMR), fast rotation, high sensitivity to perturbations (especially solar radiation pressure) and change of area-to-mass ratio (AMR) over time. As a result, traditional models (e.g. cannonball) are unsuitable to represent and predict this debris' orbital evolution. Previous work by the authors effectively modelled the flexible debris by means of multibody dynamics to improve the prediction accuracy. The orbit evolution with the flexible model resulted significantly different from using the rigid model. This paper aims to present a methodology to determine the dynamic properties of thin membranes with the purpose to validate the deformation characteristics of the flexible model. A high-vacuum chamber (10-4 mbar) to significantly decrease air friction, inside which a thin membrane is hinged at one end but free at the other provides the experimental setup. A free motion test is used to determine the damping characteristics and natural frequency of the thin membrane via logarithmic decrement and frequency response. The membrane can swing freely in the chamber and the motion is tracked by a static, optical camera, and a Kalman filter technique is implemented in the tracking algorithm to reduce noise and increase the tracking accuracy of the oscillating motion. Then, the effect of solar radiation pressure on the thin membrane is investigated: a high power spotlight (500-2000 W) is used to illuminate the sample and any displacement of the membrane is measured by means of a high-resolution laser sensor. Analytic methods from the natural frequency response and Finite Element Analysis (FEA) including multibody simulations of both experimental setups are used for the validation of the flexible model by comparing the experimental results of amplitude decay, natural frequencies and deformation. The experimental results show good agreement with both analytical results and finite element methods.

How deep cells feel: Mean-field Computations and Experiments

NASA Astrophysics Data System (ADS)

Buxboim, Amnon; Sen, Shamik; Discher, Dennis E.

2009-03-01

Most cells in solid tissues exert contractile forces that mechanically couple them to elastic surroundings and that significantly influence cell adhesion, cytoskeletal organization and differentiation. However, strains within the depths of matrices are often unclear and are likely relevant to thin matrices, such as basement membranes, relative to cell size as well as to defining how far cells can ``feel.'' We present experimental results for cell spreading on thin, ligand- coated gels and for prestress in stem cells in relation to gel stiffness. Matrix thickness affects cell spread area, focal adhesions and cytoskeleton organization in stem cells, which we will compare to differentiated cells. We introduce a finite element computation to estimate the elastostatic deformations within the matrix on which a cell is placed. Interfacial strains between cell and matrix show large deviations only when soft matrices are a fraction of cell dimensions, proving consistent with experiments. 3-D cell morphologies that model stem cell-derived neurons, myoblasts, and osteoblasts show that a cylinder-shaped myoblast induces the highest strains, consistent with the prominent contractility of muscle. Groups of such cells show a weak crosstalk via matrix strains only when cells are much closer than a cell-width. Cells thus feel on length scales closer to that of adhesions than on cellular scales.

An electromagnetic microvalve for pneumatic control of microfluidic systems.

PubMed

Liu, Xuling; Li, Songjing

2014-10-01

An electromagnetic microvalve for pneumatic control of microfluidic devices has been designed, fabricated, and tested. The microvalve is composed of two parts: a miniature electromagnetic actuator and a valve body. The electromagnetic actuator consists mainly of a thin polydimethylsiloxane (PDMS)-based elastomer, which acts as the valve diaphragm. The diaphragm, used as a solid hydraulic medium, converts the large contact area of a valve core into a small contact area of valve head while maintaining a large stroking force. This microvalve remains closed because of a compressed mechanical spring force generated by the actuator. On the other hand, when a voltage is applied, the valve core moves up, relaxing the thin PDMS membrane, opening the microvalve. The fast open response (~17 ms) of the valve was achieved with a leak rate as low as 0.026 sccm at 200 KPa (N2) pressure. We tested the pertinent dynamic parameters such as flow rate in on/off mode, flow rate of duty cycles, and actuated frequencies in pulse width modulation (PWM) mode. Our method provides a simple, cheap, and small microvalve that avoids the bulky and expensive external pressure control solenoid manifold. This allows it to be easily integrated into portable and disposable devices. © 2014 Society for Laboratory Automation and Screening.

Impedance dispersion analysis of drug-membrane interactions

NASA Astrophysics Data System (ADS)

Tacheva, Bilyana; Paarvanova, Boyana; Ivanov, Ivan T.; Karabaliev, Miroslav

2017-11-01

Thin lipid films modified glassy carbon electrodes (GCE) were used in this work as model system for studying the interactions between two antipsychotic phenothiazine drugs, chlorpromazine and thioridazine, and the lipid fraction of the biomembranes. The lipid films on the electrode surface were obtained through the thinning of film-forming lipid solution deposited between an electrolyte phase and the working GC electrode. The effects of the drugs on the lipid film structure were investigated by electrochemical impedance spectroscopy (EIS). To characterize the electric properties of the lipid film the impedance of the working GCE is modeled with an equivalent circuit consisting of parallel capacitance Cp and resistance Rp. These capacitance and resistance are not frequency independent but could be calculated as equivalent Cp and Rp for each measured frequency of the impedance spectrum and presented as functions of the frequency f, Cp = Cp(f) and Rp= Rp(f). For the lipid films used in this work, it is demonstrated that both Cp(f) and Rp(f) are well approximated with power-law functions. This behavior implies that the impedance Z of the films could be analysed in terms of the well-known constant-phase angle element (CPE), which is often used to describe the interfacial impedance of solid working electrodes.

Thin layer drying of cassava starch using continuous vibrated fluidized bed dryer

NASA Astrophysics Data System (ADS)

Suherman, Trisnaningtyas, Rona

2015-12-01

This paper present the experimental work and thin layer modelling of cassava starch drying in continuous vibrated fluidized bed dryer. The experimental data was used to validate nine thin layer models of drying curve. Cassava starch with 0.21 initial moisture content was dried in different air drying temperature (50°C, 55°C, 60°C, 65°C, 70°C), different weir height in bed (0 and 1 cm), and different solid feed flow (10 and 30 gr.minute-1). The result showed air dryer temperature has a significant effect on drying curve, while the weir height and solid flow rate are slightly. Based on value of R2, χ2, and RMSE, Page Model is the most accurate simulation for thin layer drying model of cassava starch.

Microstructural and mechanical characteristics of Ni–Cr thin films

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

Petley, Vijay; Sathishkumar, S.; Thulasi Raman, K.H.

2015-06-15

Highlights: • Ni–Cr thin films of varied composition deposited by DC magnetron co-sputtering. • Thin film with Ni–Cr: 80–20 at% composition exhibits most distinct behavior. • The films were tensile tested and exhibited no cracking till the substrate yielding. - Abstract: Ni–Cr alloy thin films have been deposited using magnetron co-sputtering technique at room temperature. Crystal structure was evaluated using GIXRD. Ni–Cr solid solution upto 40 at% of Cr exhibited fcc solid solution of Cr in Ni and beyond that it exhibited bcc solid solution of Ni in Cr. X-ray diffraction analysis shows formation of (1 1 1) fiber texturemore » in fcc and (2 2 0) fiber texture in bcc Ni–Cr thin films. Electron microscopy in both in-plane and transverse direction of the film surface revealed the presence of columnar microstructure for films having Cr upto 40 at%. Mechanical properties of the films are evaluated using nanoindentation. The modulus values increased with increase of Cr at% till the film is fcc. With further increase in Cr at% the modulus values decreased. Ni–Cr film with 20 at% Ni exhibits reduction in modulus and is correlated to the poor crystallization of the film as reflected in XRD analysis. The Ni–Cr thin film with 80 at% Ni and 20 at% Cr exhibited the most distinct columnar structure with highest electrical resistivity, indentation hardness and elastic modulus.« less

Composite perfluorohydrocarbon membranes, their preparation and use

DOEpatents

Ding, Yong; Bikson, Benjamin

2017-04-04

Composite porous hydrophobic membranes are prepared by forming a perfluorohydrocarbon layer on the surface of a preformed porous polymeric substrate. The substrate can be formed from poly (aryl ether ketone) and a perfluorohydrocarbon layer can be chemically grafted to the surface of the substrate. The membranes can be utilized for a broad range of fluid separations, such as microfiltration, nanofiltration, ultrafiltration as membrane contactors for membrane distillation and for degassing and dewatering of fluids. The membranes can further contain a dense ultra-thin perfluorohydrocarbon layer superimposed on the porous poly (aryl ether ketone) substrate and can be utilized as membrane contactors or as gas separation. membranes for natural gas treatment and gas dehydration.

Composite electrolytes of polyethylene oxides/garnets interfacially wetted by ionic liquid for room-temperature solid-state lithium battery

NASA Astrophysics Data System (ADS)

Huo, Hanyu; Zhao, Ning; Sun, Jiyang; Du, Fuming; Li, Yiqiu; Guo, Xiangxin

2017-12-01

Paramount attention has been paid on solid polymer electrolytes due to their potential in enhancement of energy density as well as improvement of safety. Herein, the composite electrolytes consisting of Li-salt-free polyethylene oxides and 200 nm-sized Li6.4La3Zr1.4Ta0.6O12 particles interfacially wetted by [BMIM]TF2N of 1.8 μL cm-2 have been prepared. Such wetted ionic liquid remains the solid state of membrane electrolytes and decreases the interface impedance between the electrodes and the electrolytes. There is no release of the liquid phase from the PEO matrix when the pressure of 5.0 × 104 Pa being applied for 24 h. The interfacially wetted membrane electrolytes show the conductivity of 2.2 × 10-4 S cm-1 at 20 °C, which is one order of magnitude greater than that of the membranes without the wetted ionic liquids. The conduction mechanism is related to a large number of lithium ions releasing from Li6.4La3Zr1.4Ta0.6O12 particles and the improved conductive paths along the ion-liquid-wetted interfaces between the polymer matrix and ceramic grains. When the membranes being used in the solid-state LiFePO4/Li and LiFe0.15Mn0.85PO4/Li cells at 25 °C, the excellent rate capability and superior cycle stability has been shown. The results provide a new prospect for solid polymer electrolytes used for room-temperature solid-state lithium batteries.

Scalable bonding of nanofibrous polytetrafluoroethylene (PTFE) membranes on microstructures

NASA Astrophysics Data System (ADS)

Mortazavi, Mehdi; Fazeli, Abdolreza; Moghaddam, Saeed

2018-01-01

Expanded polytetrafluoroethylene (ePTFE) nanofibrous membranes exhibit high porosity (80%-90%), high gas permeability, chemical inertness, and superhydrophobicity, which makes them a suitable choice in many demanding fields including industrial filtration, medical implants, bio-/nano- sensors/actuators and microanalysis (i.e. lab-on-a-chip). However, one of the major challenges that inhibit implementation of such membranes is their inability to bond to other materials due to their intrinsic low surface energy and chemical inertness. Prior attempts to improve adhesion of ePTFE membranes to other surfaces involved surface chemical treatments which have not been successful due to degradation of the mechanical integrity and the breakthrough pressure of the membrane. Here, we report a simple and scalable method of bonding ePTFE membranes to different surfaces via the introduction of an intermediate adhesive layer. While a variety of adhesives can be used with this technique, the highest bonding performance is obtained for adhesives that have moderate contact angles with the substrate and low contact angles with the membrane. A thin layer of an adhesive can be uniformly applied onto micro-patterned substrates with feature sizes down to 5 µm using a roll-coating process. Membrane-based microchannel and micropillar devices with burst pressures of up to 200 kPa have been successfully fabricated and tested. A thin layer of the membrane remains attached to the substrate after debonding, suggesting that mechanical interlocking through nanofiber engagement is the main mechanism of adhesion.

Localization of cellulose synthase in Acetobacter xylinum

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

Bureau, T.E.

1987-01-01

The cytoplasmic and outer membranes of Acetobacter xylinum (ATCC 53582) were isolated by discontinuous sucrose density ultracentrifugation. Both lysozyme and trypsin were required for efficient crude membrane separation. Primary dehydrogenases and NADH oxidase were used as cytoplasmic membrane markers, and 2-keto-3-deoxy-octulosonic acid was used to identify the outer membranes. Cellulose synthetase activity was assayed as the conversion of radioactivity from UDP-(/sup 14/C)glucose into an alkali-insoluble ..beta..-1,4-D-(/sup 14/C)glucan. The cellulosic nature of the product was demonstrated by enzymatic hydrolysis followed by thin-layer chromatography, and by methylation analysis followed by thin-layer chromatography and gas chromatography-mass spectroscopy. X-ray diffraction analysis indicated that themore » in vitro product is cellulose II which is in contrast to the in vivo product, namely cellulose I. In addition, no microfibrillar morphology could be observed from negative stained and metal shadowed preparations of the in vitro product.« less

Performance of an anisotropic Allman/DKT 3-node thin triangular flat shell element

NASA Astrophysics Data System (ADS)

Ertas, A.; Krafcik, J. T.; Ekwaro-Osire, S.

1992-05-01

A simple, explicit formulation of the stiffness matrix for an anisotropic, 3-node, thin triangular flat shell element in global coordinates is presented. An Allman triangle (AT) is used for membrane stiffness. The membrane stiffness matrix is explicitly derived by applying an Allman transformation to a Felippa 6-node linear strain triangle (LST). Bending stiffness is incorporated by the use of a discrete Kirchhoff triangle (DKT) bending element. Stiffness terms resulting from anisotropic membrane-bending coupling are included by integrating, in area coordinates, the membrane and bending strain-displacement matrices. Using the aforementioned approach, the objective of this study is to develop and test the performance of a practical 3-node flat shell element that could be used in plate problems with unsymmetrically stacked composite laminates. The performance of the latter element is tested on plates of varying aspect ratios. The developed 3-node shell element should simplify the programming task and have the potential of reducing the computational time.

Frequency-dependent stability of CNT Joule heaters in ionizable media and desalination processes

NASA Astrophysics Data System (ADS)

Dudchenko, Alexander V.; Chen, Chuxiao; Cardenas, Alexis; Rolf, Julianne; Jassby, David

2017-07-01

Water shortages and brine waste management are increasing challenges for coastal and inland regions, with high-salinity brines presenting a particularly challenging problem. These high-salinity waters require the use of thermally driven treatment processes, such as membrane distillation, which suffer from high complexity and cost. Here, we demonstrate how controlling the frequency of an applied alternating current at high potentials (20 Vpp) to a porous thin-film carbon nanotube (CNT)/polymer composite Joule heating element can prevent CNT degradation in ionizable environments such as high-salinity brines. By operating at sufficiently high frequencies, these porous thin-films can be directly immersed in highly ionizable environments and used as flow-through heating elements. We demonstrate that porous CNT/polymer composites can be used as self-heating membranes to directly heat high-salinity brines at the water/vapour interface of the membrane distillation element, achieving high single-pass recoveries that approach 100%, far exceeding standard membrane distillation recovery limits.

Contact interaction of thin-walled elements with an elastic layer and an infinite circular cylinder under torsion

NASA Astrophysics Data System (ADS)

Kanetsyan, E. G.; Mkrtchyan, M. S.; Mkhitaryan, S. M.

2018-04-01

We consider a class of contact torsion problems on interaction of thin-walled elements shaped as an elastic thin washer – a flat circular plate of small height – with an elastic layer, in particular, with a half-space, and on interaction of thin cylindrical shells with a solid elastic cylinder, infinite in both directions. The governing equations of the physical models of elastic thin washers and thin circular cylindrical shells under torsion are derived from the exact equations of mathematical theory of elasticity using the Hankel and Fourier transforms. Within the framework of the accepted physical models, the solution of the contact problem between an elastic washer and an elastic layer is reduced to solving the Fredholm integral equation of the first kind with a kernel representable as a sum of the Weber–Sonin integral and some integral regular kernel, while solving the contact problem between a cylindrical shell and solid cylinder is reduced to a singular integral equation (SIE). An effective method for solving the governing integral equations of these problems are specified.

Recent advances in solid polymer electrolyte fuel cell technology

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

Ticianelli, E.A.; Srinivasan, S.; Gonzalez, E.R.

1988-01-01

With methods used to advance solid polymer electrolyte fuel cell technology, we are close to obtaining the goal of 1 A/cm/sup 2/ at 0.7. Higher power densities have been reported (2 A/cm/sup 2/ at 0.5 V) but only with high catalyst loading electrodes (2 mg/cm/sup 2/ and 4 mg/cm/sup 2/ at anode and cathode, respectively) and using a Dow membrane with a better conductivity and water retention characteristics. Work is in progress to ascertain performances of cells with Dow membrane impregnated electrodes and Dow membrane electrolytes. 5 refs., 6 figs.

The Characterization of Thin Film Nickel Titanium Shape Memory Alloys

NASA Astrophysics Data System (ADS)

Harris Odum, Nicole Latrice

Shape memory alloys (SMA) are able to recover their original shape through the appropriate heat or stress exposure after enduring mechanical deformation at a low temperature. Numerous alloy systems have been discovered which produce this unique feature like TiNb, AgCd, NiAl, NiTi, and CuZnAl. Since their discovery, bulk scale SMAs have undergone extensive material property investigations and are employed in real world applications. However, its thin film counterparts have been modestly investigated and applied. Researchers have introduced numerous theoretical microelectromechanical system (MEMS) devices; yet, the research community's overall unfamiliarity with the thin film properties has delayed growth in this area. In addition, it has been difficult to outline efficient thin film processing techniques. In this dissertation, NiTi thin film processing and characterization techniques will be outlined and discussed. NiTi thin films---1 mum thick---were produced using sputter deposition techniques. Substrate bound thin films were deposited to analysis the surface using Scanning Electron Microscopy; the film composition was obtained using Energy Dispersive Spectroscopy; the phases were identified using X-ray diffraction; and the transformation temperatures acquired using resistivity testing. Microfabrication processing and sputter deposition were employed to develop tensile membranes for membrane deflection experimentation to gain insight on the mechanical properties of the thin films. The incorporation of these findings will aid in the movement of SMA microactuation devices from theory to fruition and greatly benefit industries such as medicinal and aeronautical.

Manufacturing and characterization of a ceramic single-use microvalve

NASA Astrophysics Data System (ADS)

Khaji, Z.; Klintberg, L.; Thornell, G.

2016-09-01

We present the manufacturing and characterization of a ceramic single-use microvalve with the potential to be integrated in lab-on-a-chip devices, and forsee its utilization in space and other demanding applications. A 3 mm diameter membrane was used as the flow barrier, and the opening mechanism was based on cracking the membrane by inducing thermal stresses on it with fast and localized resistive heating. Four manufacturing schemes based on high-temperature co-fired ceramic technology were studied. Three designs for the integrated heaters and two thicknesses of 40 and 120 μm for the membranes were considered, and the heat distribution over their membranes, the required heating energies, their opening mode, and the flows admitted through were compared. Furthermore, the effect of applying  +1 and  -1 bar pressure difference on the membrane during cracking was investigated. Thick membranes demonstrated unpromising results for low-pressure applications since the heating either resulted in microcracks or cracking of the whole chip. Because of the higher pressure tolerance of the thick membranes, the design with microcracks can be considered for high-pressure applications where flow is facilitated anyway. Thin membranes, on the other hand, showed different opening sizes depending on heater design and, consequently, heat distribution over the membranes, from microcracks to holes with sizes of 3-100% of the membrane area. For all the designs, applying  +1 bar over pressure contributed to bigger openings, whereas  -1 bar pressure difference only did so for one of the designs, resulting in smaller openings for the other two. The energy required for breaking these membranes was a few hundred mJ with no significant dependence on design and applied pressure. The maximum sustainable pressure of the valve for the current design and thin membranes was 7 bar.

Fabrication of zinc-dicarboxylate- and zinc-pyrazolate-carboxylate-framework thin films through vapour-solid deposition.

PubMed

Medishetty, Raghavender; Zhang, Zongji; Sadlo, Alexander; Cwik, Stefan; Peeters, Daniel; Henke, Sebastian; Mangayarkarasi, Nagarathinam; Devi, Anjana

2018-05-17

Fabrication of three-dimensional metal-organic framework (MOF) thin films has been investigated for the first time through the conversion of a ZnO layer via a pure vapour-solid deposition reaction at ambient pressure. The fabrication of MOF thin films with a dicarboxylate linker, (DMA)2[Zn3(bdc)4] (1) (bdc = 1,4-benzenedicarboxylate), and a carboxy-pyrazolate linker, [Zn4O(dmcapz)6] (2) (dmcapz = 3,5-dimethyl-4-carboxypyrazole), involves the deposition of the linker and/or the preparation of a composite film preliminarily and its subsequent conversion into a MOF film using closed cell thermal treatment. Furthermore, it was possible to isolate thin films with a MOF-5 isotype structure grown along the [110] direction, using a carboxy-pyrazolate linker. This was achieved just by the direct reaction of the ZnO film and the organic linker vapors, employing a simple route that demonstrates the feasibility of MOF thin film fabrication using inexpensive routes at ambient pressure.

Fundamental Studies on Confinement Effects in Ionic Conduction and Inversion Layers in 2-D Single Crystal Free Standing Oxide Membranes

DTIC Science & Technology

2014-02-14

properties of VO2 films and membranes and compare the results with annealing VO2 films and membranes in hydrogen to provide insight into the doping...2-dimensional free standing membrane with correlated oxides may also lead to new insights into mesoscopic electronic phenomena. Vanadium oxide ( VO2 ...well as for potential applications in switching devices. While studies have been conducted on thin films, hybrid layers of VO2 supported on other

INTERNAL LIMITING MEMBRANE PEELING-DEPENDENT RETINAL STRUCTURAL CHANGES AFTER VITRECTOMY IN RHEGMATOGENOUS RETINAL DETACHMENT.

PubMed

Hisatomi, Toshio; Tachibana, Takashi; Notomi, Shoji; Koyanagi, Yoshito; Murakami, Yusuke; Takeda, Atsunobu; Ikeda, Yasuhiro; Yoshida, Shigeo; Enaida, Hiroshi; Murata, Toshinori; Sakamoto, Taiji; Sonoda, Koh-Hei; Ishibashi, Tatsuro

2018-03-01

To examine retinal changes after vitrectomy with internal limiting membrane (ILM) peeling, we used 3-dimensional optical coherence tomography (3D-OCT) in rhegmatogenous retinal detachment cases. The 68 eyes from 67 patients with rhegmatogenous retinal detachment were studied, including 35 detached macula cases (51%) and 33 attached macula cases. Internal limiting membrane peeling was performed with fine forceps after brilliant blue G staining. The 3D-OCT images were obtained with volume-rendering technologies from cross-sectional OCT images. The 3D-OCT detected 45 eyes (66%) with ILM peeling-dependent retinal changes, including dissociated optic nerve fiber layer appearance, dimple sign, temporal macular thinning, ILM peeling area thinning, or forceps-related retinal thinning. The ILM peeled area was detectable in only 9 eyes with 3D-OCT, whereas it was undetectable in other 59 eyes. The dissociated optic nerve fiber layer appearance was detected in 8 of the total cases (12%), and dimple signs were observed in 14 cases (21%). Forceps-related thinning was also noted in eight cases (24%) of attached macula cases and in four cases (11%) of detached macula cases. No postoperative macular pucker was noted in the observational period. The 3D-OCT clearly revealed spatial and time-dependent retinal changes after ILM peeling. The changes occurred in 2 months and remained thereafter.

Engineering membrane scaffolds with both physical and biomolecular signaling.

PubMed

Tejeda-Montes, Esther; Smith, Katherine H; Poch, Marta; López-Bosque, María Jesús; Martín, Laura; Alonso, Matilde; Engel, Elisabeth; Mata, Alvaro

2012-03-01

We report on the combination of a top-down and bottom-up approach to develop thin bioactive membrane scaffolds based on functional elastin-like polymers (ELPs). Our strategy combines ELP cross-linking and assembly, and a variety of standard and novel micro/nanofabrication techniques to create self-supporting membranes down to ∼500 nm thick that incorporate both physical and biomolecular signals, which can be easily tailored for a specific application. In this study we used an ELP that included the cell-binding motif arginine-glycine-aspartic acid-serine (RGDS). Furthermore, fabrication processes were developed to create membranes that exhibited topographical patterns with features down to 200 nm in lateral dimensions and up to 10 μm in height on either one or both sides, uniform and well-defined pores, or multiple ELP layers. A variety of processing parameters were tested in order to optimize membrane fabrication, including ELP and cross-linker concentration, temperature, reaction time and ambient humidity. Membrane micro/nanopatterning, swelling and stiffness were characterized by atomic force microscopy, nanoindentation tests and scanning electron microscopy. Upon immersion in phosphate-buffered saline and an increase in temperature from 25 to 40°C, membranes exhibited a significant increase in surface stiffness, with the reduced Young's modulus increasing with temperature. Finally, rat mesenchymal stem cells were cultured on thin RGDS-containing membranes, which allowed cell adhesion, qualitatively enhanced spreading compared to membranes without RGDS epitopes and permitted proliferation. Furthermore, cell morphology was drastically affected by topographical patterns on the surface of the membranes. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Carbon Nanomembranes

NASA Astrophysics Data System (ADS)

Angelova, Polina; Gölzhäuser, Armin

2017-03-01

This chapter describes the formation and properties of one nanometer thick carbon nanomembranes (CNMs), made by electron induced cross-linking of aromatic self-assembled monolayers (SAMs). The cross-linked SAMs are robust enough to be released from the surface and placed on solid support or over holes as free-standing membranes. Annealing at 1000K transforms CNMs into graphene accompanied by a change of mechanical stiffness and electrical resistance. The developed fabrication approach is scalable and provides molecular level control over thickness and homogeneity of the produced CNMs. The mechanisms of electron-induced cross-linking process are discussed in details. A variety of polyaromatic thiols: oligophenyls as well as small and extended condensed polycyclic hydrocarbons have been successfully employed, demonstrating that the structural and functional properties of the resulting nanomembranes are strongly determined by the structure of molecular monolayers. The mechanical properties of CNMs (Young's modulus, tensile strength and prestress) are characterized by bulge testing. The interpretation of the bulge test data relates the Young's modulus to the properties of single molecules and to the structure of the pristine SAMs. The gas transport through the CNM is measured onto polydimethylsiloxane (PDMS) - thin film composite membrane. The established relationship of permeance and molecular size determines the molecular sieving mechanism of permeation through this ultrathin sheet.

Easy Fabrication of Thin Membranes with Through Holes. Application to Protein Patterning

PubMed Central

Arasi, Bakya; Gauthier, Nils; Viasnoff, Virgile

2012-01-01

Since protein patterning on 2D surfaces has emerged as an important tool in cell biology, the development of easy patterning methods has gained importance in biology labs. In this paper we present a simple, rapid and reliable technique to fabricate thin layers of UV curable polymer with through holes. These membranes are as easy to fabricate as microcontact printing stamps and can be readily used for stencil patterning. We show how this microfabrication scheme allows highly reproducible and highly homogeneous protein patterning with micron sized resolution on surfaces as large as 10 cm2. Using these stencils, fragile proteins were patterned without loss of function in a fully hydrated state. We further demonstrate how intricate patterns of multiple proteins can be achieved by stacking the stencil membranes. We termed this approach microserigraphy. PMID:22952944

X-ray lithography masking

NASA Technical Reports Server (NTRS)

Smith, Henry I. (Inventor); Lim, Michael (Inventor); Carter, James (Inventor); Schattenburg, Mark (Inventor)

1998-01-01

X-ray masking apparatus includes a frame having a supporting rim surrounding an x-ray transparent region, a thin membrane of hard inorganic x-ray transparent material attached at its periphery to the supporting rim covering the x-ray transparent region and a layer of x-ray opaque material on the thin membrane inside the x-ray transparent region arranged in a pattern to selectively transmit x-ray energy entering the x-ray transparent region through the membrane to a predetermined image plane separated from the layer by the thin membrane. A method of making the masking apparatus includes depositing back and front layers of hard inorganic x-ray transparent material on front and back surfaces of a substrate, depositing back and front layers of reinforcing material on the back and front layers, respectively, of the hard inorganic x-ray transparent material, removing the material including at least a portion of the substrate and the back layers of an inside region adjacent to the front layer of hard inorganic x-ray transparent material, removing a portion of the front layer of reinforcing material opposite the inside region to expose the surface of the front layer of hard inorganic x-ray transparent material separated from the inside region by the latter front layer, and depositing a layer of x-ray opaque material on the surface of the latter front layer adjacent to the inside region.

Surface nanostructuring of thin film composite membranes via grafting polymerization and incorporation of ZnO nanoparticles

NASA Astrophysics Data System (ADS)

Isawi, Heba; El-Sayed, Magdi H.; Feng, Xianshe; Shawky, Hosam; Abdel Mottaleb, Mohamed S.

2016-11-01

A new approach for modification of polyamid thin film composite membrane PA(TFC) using synthesized ZnO nanoparticles (ZnO NPs) was shown to enhance the membrane performances for reverse osmosis water desalination. First, active layer of synthesis PA(TFC) membrane was activated with an aqueous solution of free radical graft polymerization of hydrophilic methacrylic acid (MAA) monomer onto the surface of the PA(TFC) membrane resulting PMAA-g-PA(TFC). Second, the PA(TFC) membrane has been developed by incorporation of ZnO NPs into the MAA grafting solution resulting the ZnO NPs modified PMAA-g-PA(TFC) membrane. The surface properties of the synthesized nanoparticles and prepared membranes were investigated using the FTIR, XRD and SEM. Morphology studies demonstrated that ZnO NPs have been successfully incorporated into the active grafting layer over PA(TFC) composite membranes. The zinc leaching from the ZnO NPs modified PMAA-g-PA(TFC) was minimal, as shown by batch tests that indicated stabilization of the ZnO NPs on the membrane surfaces. Compared with the a pure PA(TFC) and PMAA-g-PA(TFC) membranes, the ZnO NPs modified PMAA-g-PA(TFC) was more hydrophilic, with an improved water contact angle (∼50 ± 3°) over the PMAA-g-PA(TFC) (63 ± 2.5°). The ZnO NPs modified PMAA-g-PA(TFC) membrane showed salt rejection of 97% (of the total groundwater salinity), 99% of dissolved bivalent ions (Ca2+, SO42-and Mg2+), and 98% of mono valent ions constituents (Cl- and Na+). In addition, antifouling performance of the membranes was determined using E. coli as a potential foulant. This demonstrates that the ZnO NPs modified PMAA-g-PA(TFC) membrane can significantly improve the membrane performances and was favorable to enhance the selectivity, permeability, water flux, mechanical properties and the bio-antifouling properties of the membranes for water desalination.

DNA nanotechnology: Bringing lipid bilayers into shape

NASA Astrophysics Data System (ADS)

Howorka, Stefan

2017-07-01

Lipid bilayers form the thin and floppy membranes that define the boundary of compartments such as cells. Now, a method to control the shape and size of bilayers using DNA nanoscaffolds has been developed. Such designer materials advance synthetic biology and could find use in membrane research.

Study of Asorption Kinetics of Surfactants onto Polyethersulfone Membrane Surface Using QCM-D

USDA-ARS?s Scientific Manuscript database

The adsorption kinetics of surfactants onto the crystal surface spin-coated with a thin layer of a model membrane material, polyethersulfone was monitored through measurements of frequency and dissipation shifts simultaneously using a quartz crystal microbalance with dissipation (QCM-D) device. In ...

SEPARATION OF HAZARDOUS ORGANICS BY LOW PRESSURE REVERSE OSMOSIS MEMBRANES - PHASE II FINAL REPORT

EPA Science Inventory

Extensive experimental studies showed that thin-film, composite membranes can be used effectively for the separation of selected hazardous organic compounds. This waste treatment technique offers definite advantages in terms of high solute separations at low pressures (<2MPa) and...

Template Synthesis of Nanostructured Polymeric Membranes by Inkjet Printing.

PubMed

Gao, Peng; Hunter, Aaron; Benavides, Sherwood; Summe, Mark J; Gao, Feng; Phillip, William A

2016-02-10

The fabrication of functional nanomaterials with complex structures has been serving great scientific and practical interests, but current fabrication and patterning methods are generally costly and laborious. Here, we introduce a versatile, reliable, and rapid method for fabricating nanostructured polymeric materials. The novel method is based on a combination of inkjet printing and template synthesis, and its utility and advantages in the fabrication of polymeric nanomaterials is demonstrated through three examples: the generation of polymeric nanotubes, nanowires, and thin films. Layer-by-layer-assembled nanotubes can be synthesized in a polycarbonate track-etched (PCTE) membrane by printing poly(allylamine hydrochloride) and poly(styrenesulfonate) sequentially. This sequential deposition of polyelectrolyte ink enables control over the surface charge within the nanotubes. By a simple change of the printing conditions, polymeric nanotubes or nanowires were prepared by printing poly(vinyl alcohol) in a PCTE template. In this case, the high-throughput nature of the method enables functional nanomaterials to be generated in under 3 min. Furthermore, we demonstrate that inkjet printing paired with template synthesis can be used to generate patterns comprised of chemically distinct nanomaterials. Thin polymeric films of layer-by-layer-assembled poly(allylamine hydrochloride) and poly(styrenesulfonate) are printed on a PCTE membrane. Track-etched membranes covered with the deposited thin films reject ions and can potentially be utilized as nanofiltration membranes. When the fabrication of these different classes of nanostructured materials is demonstrated, the advantages of pairing template synthesis with inkjet printing, which include fast and reliable deposition, judicious use of the deposited materials, and the ability to design chemically patterned surfaces, are highlighted.

Thin and flexible all-solid supercapacitor prepared from novel single wall carbon nanotubes/polyaniline thin films obtained in liquid-liquid interfaces

NASA Astrophysics Data System (ADS)

de Souza, Victor Hugo Rodrigues; Oliveira, Marcela Mohallem; Zarbin, Aldo José Gorgatti

2014-08-01

The present work describes for the first time the synthesis and characterization of single wall carbon nanotubes/polyaniline (SWNTs/PAni) nanocomposite thin films in a liquid-liquid interface, as well as the subsequent construction of a flexible all-solid supercapacitor. Different SWNTs/PAni nanocomposites were prepared by varying the ratio of SWNT to aniline, and the samples were characterized by scanning and transmission electron microscopy, Raman and UV-Vis spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The pseudo-capacitive behavior of the nanocomposites was evaluated by charge/discharge galvanostatic measurements. The presence of the SWNTs affected the electronic and vibrational properties of the polyaniline and also improved the pseudo-capacitive behavior of the conducting polymer. A very thin and flexible all-solid device was manufactured using two electrodes (polyethylene terephthalate-PET covered with the SWNT/PAni nanocomposite separated by a H2SO4-PVA gel electrolyte). The pseudo-capacitive behavior was characterized by a volumetric specific capacitance of approximately 76.7 F cm-3, even under mechanical deformation, indicating that this nanocomposite has considerable potential for application in new-generation energy storage devices.

21 CFR 177.2550 - Reverse osmosis membranes.

Code of Federal Regulations, 2014 CFR

2014-04-01

... maximum weight is 62 milligrams per square decimeter (4 milligrams per square inch) as a thin film... square decimeter (0.3 milligrams per square inch) as a thin film composite on a suitable support. The... square decimeter (0.03 milligrams per square inch). (3) For the purpose of this section, the reverse...

Fractal avalanche ruptures in biological membranes

NASA Astrophysics Data System (ADS)

Gözen, Irep; Dommersnes, Paul; Czolkos, Ilja; Jesorka, Aldo; Lobovkina, Tatsiana; Orwar, Owe

2010-11-01

Bilayer membranes envelope cells as well as organelles, and constitute the most ubiquitous biological material found in all branches of the phylogenetic tree. Cell membrane rupture is an important biological process, and substantial rupture rates are found in skeletal and cardiac muscle cells under a mechanical load. Rupture can also be induced by processes such as cell death, and active cell membrane repair mechanisms are essential to preserve cell integrity. Pore formation in cell membranes is also at the heart of many biomedical applications such as in drug, gene and short interfering RNA delivery. Membrane rupture dynamics has been studied in bilayer vesicles under tensile stress, which consistently produce circular pores. We observed very different rupture mechanics in bilayer membranes spreading on solid supports: in one instance fingering instabilities were seen resulting in floral-like pores and in another, the rupture proceeded in a series of rapid avalanches causing fractal membrane fragmentation. The intermittent character of rupture evolution and the broad distribution in avalanche sizes is consistent with crackling-noise dynamics. Such noisy dynamics appear in fracture of solid disordered materials, in dislocation avalanches in plastic deformations and domain wall magnetization avalanches. We also observed similar fractal rupture mechanics in spreading cell membranes.

Flexible robust binder-free carbon nanotube membranes for solid state and microcapacitor application

NASA Astrophysics Data System (ADS)

Adu, Kofi; Ma, Danhao; Wang, Yuxiang; Spencer, Michael; Rajagopalan, Ramakrishnan; Wang, C.-Yu; Randall, Clive

2018-01-01

We present a liquid phase post synthesis self-assemble protocol that transforms trillions of carbon nanotubes (CNTs) in powder form into densely packed flexible, robust and binder-free macroscopic membranes with a hierarchical pore structure. We employ charge transfer engineering to spontaneously disperse the CNTs in a liquid medium. The processing protocol has limited or no impact on the intrinsic properties of the CNTs. As the thickness of the CNT membrane is increased, we observed a gradual transition from high flexibility to buckling and brittleness in the flexural properties of the membranes. The binder-free CNT membranes have bulk mass density greater than that of water (1.0 g cm-3). We correlate the mass of the CNTs in the membrane to the thickness of the membrane and obtained a bulk mass density of ˜1.11 g cm-3 ± 0.03 g cm-3. We demonstrate the use of the CNT membranes as electrode in a pristine and oxidized single/stacked solid-state capacitor as well as pristine interdigitated microcapacitor that show time constant of ˜32 ms with no degradation in performance even after 10 000 cycles. The capacitors show very good temperature dependence over a wide range of temperatures with good cycling performance up to 90 °C. The specific capacitance of the pseudocapacitive CNT electrode at room temperature was 72 F g-1 and increased to 100 F g-1 at 70 °C. The leakage current of bipolar stacked solid state capacitor was ˜100 nA cm-2 at 2.5 V when held for 72 h.

Silicon Nanostructures, Excitonic Interactions, Laser Consequences

DTIC Science & Technology

2008-07-11

etching using an anodized aluminum oxide membrane as mask. The results described here lay a solid foundation for the next phase of development aimed at...achieved though reactive-ion-etching using an anodized aluminum oxide membrane as mask. The results described here lay a solid foundation for the next...Materials, April 4, 2006 issue). 6. Aijun Yin, Marian Tzolov, David Cardimona and Jimmy Xu, "Fabrication of Highly Ordered Anodic Aluminum Oxide

Dynamic Structure of Bombolitin II Bound to Lipid Bilayers as Revealed by Solid-state NMR and Molecular-Dynamics Simulation

PubMed Central

Toraya, Shuichi; Javkhlantugs, Namsrai; Mishima, Daisuke; Nishimura, Katsuyuki; Ueda, Kazuyoshi; Naito, Akira

2010-01-01

Bombolitin II (BLT2) is one of the hemolytic heptadecapeptides originally isolated from the venom of a bumblebee. Structure and orientation of BLT2 bound to 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) membranes were determined by solid-state 31P and 13C NMR spectroscopy. 31P NMR spectra showed that BLT2-DPPC membranes were disrupted into small particles below the gel-to-liquid crystalline phase transition temperature (Tc) and fused to form a magnetically oriented vesicle system where the membrane surface is parallel to the magnetic fields above the Tc. 13C NMR spectra of site-specifically 13C-labeled BLT2 at the carbonyl carbons were observed and the chemical shift anisotropies were analyzed to determine the dynamic structure of BLT2 bound to the magnetically oriented vesicle system. It was revealed that the membrane-bound BLT2 adopted an α-helical structure, rotating around the membrane normal with the tilt angle of the helical axis at 33°. Interatomic distances obtained from rotational-echo double-resonance experiments further showed that BLT2 adopted a straight α-helical structure. Molecular dynamics simulation performed in the BLT2-DPPC membrane system showed that the BLT2 formed a straight α-helix and that the C-terminus was inserted into the membrane. The α-helical axis is tilted 30° to the membrane normal, which is almost the same as the value obtained from solid-state NMR. These results suggest that the membrane disruption induced by BLT2 is attributed to insertion of BLT2 into the lipid bilayers. PMID:21081076

Development of novel nano-composite membranes as introduction systems for mass spectrometers: Contrasting nano-composite membranes and conventional inlet systems

NASA Astrophysics Data System (ADS)

Miranda, Luis Diego

This dissertation presents the development of novel nano-composite membranes as introduction systems for mass spectrometers. These nano-composite membranes incorporate anodic aluminum oxide (AAO) membranes as templates that can be used by themselves or modified by a variety of chemical deposition processes. Two types of nano-composite membranes are presented. The first nano-composite membrane has carbon deposited within the pores of an AAO membrane. The second nano-composite membrane is made by coating an AAO membrane with a thin polymer film. The following chapters describe the transmission properties these nano-composite membranes and compare them to conventional mass spectrometry introduction systems. The nano- composite membranes were finally coupled to the inlet system of an underwater mass spectrometer revealing their utility in field deployments.

Solid state dewetting of thin plasmonic films under focused cw-laser irradiation

DOE PAGES

Abbott, William M.; Corbett, Simon; Cunningham, Graeme; ...

2017-12-21

Elevated temperatures and large thermal gradients are a significant source of component failure in microelectronics, and is the limiting factor in heat-assisted magnetic recording (HAMR). Here, we have investigated the effect of solid-state dewetting in Au thin films, as a function of local temperature, film thickness, and substrate adhesion. In this work, a localised temperature rise is induced in thin (≤ 50 nm) polycrystalline Au films on SiO 2 substrates via focused continuous-wave laser irradiation at 488 nm. The magnitude and distribution of the total temperature rise is measured using CCD-based thermoreflectance. This also allows a sensitive measurement of themore » temperature at which dewetting occurs, showing that for thin (≤ 50 nm) Au films without adhesion layers, rapid dewetting can occur at temperatures as low as 50° C. The time decay of the reflected light from the illuminating laser is used to monitor locally the dynamics of solid state dewetting. TEM diffraction analysis shows significant changes in the microstructure and crystallographic texture of the films as far as 10 µm away from the illuminated area. The use of a thin metallic adhesion layer (such as Ti or Cr) is shown to significantly improve the adhesion of the Au to the substrate and reduce the tendency towards dewetting, but does not entirely protect it from changes to the crystallographic texture.« less

Solid state dewetting of thin plasmonic films under focused cw-laser irradiation

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

Abbott, William M.; Corbett, Simon; Cunningham, Graeme

Elevated temperatures and large thermal gradients are a significant source of component failure in microelectronics, and is the limiting factor in heat-assisted magnetic recording (HAMR). Here, we have investigated the effect of solid-state dewetting in Au thin films, as a function of local temperature, film thickness, and substrate adhesion. In this work, a localised temperature rise is induced in thin (≤ 50 nm) polycrystalline Au films on SiO 2 substrates via focused continuous-wave laser irradiation at 488 nm. The magnitude and distribution of the total temperature rise is measured using CCD-based thermoreflectance. This also allows a sensitive measurement of themore » temperature at which dewetting occurs, showing that for thin (≤ 50 nm) Au films without adhesion layers, rapid dewetting can occur at temperatures as low as 50° C. The time decay of the reflected light from the illuminating laser is used to monitor locally the dynamics of solid state dewetting. TEM diffraction analysis shows significant changes in the microstructure and crystallographic texture of the films as far as 10 µm away from the illuminated area. The use of a thin metallic adhesion layer (such as Ti or Cr) is shown to significantly improve the adhesion of the Au to the substrate and reduce the tendency towards dewetting, but does not entirely protect it from changes to the crystallographic texture.« less

Developmental mechanisms of the tympanic membrane in mammals and non-mammalian amniotes.

PubMed

Takechi, Masaki; Kitazawa, Taro; Hirasawa, Tatsuya; Hirai, Tamami; Iseki, Sachiko; Kurihara, Hiroki; Kuratani, Shigeru

2016-01-01

The tympanic membrane is a thin layer that originates from the ectoderm, endoderm, and mesenchyme. Molecular-genetic investigations have revealed that interaction between epithelial and mesenchymal cells in the pharyngeal arches is essential for development of the tympanic membrane. We have recently reported that developmental mechanisms underlying the tympanic membrane seem to be different between mouse and chicken, suggesting that the tympanic membrane evolved independently in mammals and non-mammalian amniotes. In this review, we summarize previous studies of tympanic membrane formation in the mouse. We also discuss its formation in amniotes from an evolutionary point of view. © 2015 Japanese Teratology Society.