Abstract: Thin layers of a mixed composition are deposited on a porous substrate by chemical vapor deposition in an inert atmosphere at high temperature. The resulting membrane has excellent stability to water vapor at high temperatures. An exemplary membrane comprises an amorphous mixed-element surface layer comprising silica and at least one oxide of additional element, an optional porous substrate on which said surface layer is deposited, and a porous support on which said substrate or mixed-element surface layer is deposited, wherein the permeance of the membrane is higher than 1×10?7 mol m?2s?1Pa?1 and the selectivity of H2 over CO, CO2, and CH4 is larger than 100, and wherein the H2 permeance of the membrane after exposure to a stream containing 60 mol % water vapor at 673 K for 120 h is at least 50% of its initial H2 permeance.

Abstract: This invention relates to a metallic composite membrane for separating hydrogen from a mixed gas, a membrane module and a manufacturing method thereof. The composite membrane consists of a three-layer sandwich structure, e.g. the porous metal substrate, an intermediate layer and the hydrogen-selective dense thin metal layer. In the embodiments of the invention, the porous metal substrates were first pretreated to reduce their surface roughness without reducing their gas permeability. The pretreated substrates were coated with intermediate layer, wherein the intermediate layer served as not only a barrier layer to prevent interdiffusion between the substrate and the hydrogen-selective layer, but also a surface modifier to reduce surface roughness and pore size of the substrate. A hydrogen-selective metal layer was then deposited on the intermediate layer-coated substrate by coating methods.

Abstract: A fuel system for an energy conversion device includes a deoxygenator system with an oxygen permeable membrane formed from a multiple of layers. The layers include a sealant layer, an oxygen permeability layer and a porous backing layer. The layered composite oxygen permeable membrane maximizes the oxygen transfer rate and minimizes the fuel leakage rate.

Abstract: It is an object of the present invention to provide a separation membrane in which a film-forming solution can be prevented from reaching a rear surface of a porous support in a step of forming a film, the adhesion between a functional film for separation and the porous support is high, and the thickness can be reduced. In the present invention, the separation membrane includes a porous support having a rough rear surface and a functional film for separation, and the functional film is disposed on a front surface of the porous support and extends into the porous support.

Abstract: A liquid-gas separator for a direct liquid feed fuel cell includes: a housing having an open hole; a gas extracting membrane that covers the open hole and transmits only the gas; a liquid extracting member that defines a first chamber that contacts the gas extracting membrane and a second chamber that does not contact the gas extracting membrane, and selectively transmits the liquid in the first chamber to the second chamber; an inlet that guides the liquid and the gas into the housing; and an outlet that is connected to the second chamber and guides the liquid in the second chamber to the outside.

Abstract: A device for hydrogen separation has a porous support and hydrogen separation material on the support. The support is prepared by heat treatment of metal microparticles, preferably of iron-based or nickel-based alloys that also include aluminum and/or yttrium. The hydrogen separation material is then deposited on the support. Preferred hydrogen separation materials include metals such as palladium, alloys, platinum, refractory metals, and alloys.

Abstract: A thermal method of making a hydrogen permeable composition is disclosed. A mixture of metal oxide powder and ceramic oxide powder and optionally a pore former is formed and pressed to form an article. The article is dried at elevated temperatures and then sintered in a reducing atmosphere to provide a dense hydrogen permeable portion near the surface of the sintered mixture. The dense hydrogen permeable portion has a higher initial concentration of metal than the remainder of the sintered mixture and is present in the range of from about 20 to about 80 percent by volume of the dense hydrogen permeable portion.

Abstract: A composite material that may be used for a thin membrane is disclosed. This composite material includes first material that has a quasi-periodic system of vertical trenches (nanotrenches) with wavelength period that may be in the range between 20 and 500 nm. These nanotrenches are formed as openings between bordering elongated elements. The nanotrenches are at least partially filled with a second material that has physical-chemical characteristics substantially different from the first material.

Abstract: Multiphasic reactions, especially those reactions using a phase transfer catalyst, are conducted in microchannel apparatus. Advantageously, these reactions can be conducted with two, planar microlayers of reactants in adjacent laminar flow streams. Microchannel apparatus and methods for conducting unit operations such as reactions and separations in microchannel apparatus is also described. Microchannel apparatus can provide advantages for controlling reactions and separating products, solvents or reactants in multiphase reactions.

Abstract: A composite filter media having excellent dust-releasing properties provided with a layer of netting formed of a low surface free energy material that is hot calendered to the upstream surface of a supporting layer formed of non-woven synthetic fibers. A filtering layer formed of non-woven synthetic fibers is laminated to the downstream surface of the supporting layer. The filtering layer may include an electrostatic charge to increase filter efficiency at a reduced pressure drop across the composite media.

Abstract: A disposable air filter for an HVAC system, especially a re-circulating system, having a first filter layer for removing larger particles and dust, and a second filter layer for removing small particles, especially reprievable particles. An expanded metal screen between layers is disclosed as a second embodiment.

Abstract: A carbon membrane laminated body includes: a porous substrate, a first porous carbon membrane as a carbon membrane underlayer disposed on a surface of the porous substrate, and a second porous carbon membrane as a carbon membrane separation layer disposed on a surface of the carbon membrane underlayer, having a smaller film thickness, and a smaller average pore diameter, compared with those of the carbon membrane underlayer. It is preferable to form the carbon membrane underlayer and the carbon membrane separation layer by carbonizing a carbon membrane underlayer precursor disposed on a surface of the porous substrate and the carbon membrane separation layer precursor disposed on a surface of the carbon membrane underlayer precursor at 400 to 1000° C. in a non-oxidation atmosphere. The carbon membrane laminated body is a separation membrane excellent in both separation performance and flux when it is used as a separation membrane of a mixture.

Abstract: The invention relates to gas separation, in particular to separation of CO2 from CO2-rich liquids, particularly from CO2 absorption liquids used in the removal of CO2 from off-gases or product flows, such as natural gas or synthesis gas. According to the invention, CO2 is separated from a CO2-rich liquid by a method comprising a step wherein, under elevated pressure, said liquid is contacted with a membrane based on polyacetylene substituted with trimethylsilyl groups such that the pressure across the membrane is at least 1 bar and that at least a part of the CO2 is transported from the liquid through the membrane.

Abstract: A nanofiber membrane is formed on a microfiber membrane. The nanofiber membrane may be electro sprayed directly onto the microfiber membrane and becomes integrated with the microfiber membrane to form a filter. The microfiber membrane provides structural integrity to for the nanofiber membrane, and an additional microfiber membrane may be added to sandwich the nanofiber membrane.

Abstract: The present invention provides methods for making a microporous ceramic material using a metal silicon powder and including a reaction sintering process of the silicon. A material for forming a microporous ceramic material used in these methods includes a metal silicon powder, a silicon nitride powder and/or a silicon carbide powder, and if desired, a yttrium oxide powder and/or an aluminum oxide powder. These methods can make a microporous ceramic material that can be used preferably as a gas or liquid filter, a catalyst carrier or a support of a gas separation membrane.

Abstract: A mixed ionic and electronic conducting membrane includes a two-phase solid state ceramic composite, wherein the first phase comprises an oxygen ion conductor and the second phase comprises an n-type electronically conductive oxide, wherein the electronically conductive oxide is stable at an oxygen partial pressure as low as 10?20 atm and has an electronic conductivity of at least 1 S/cm. A hydrogen separation system and related methods using the mixed ionic and electronic conducting membrane are described.

Abstract: A temperature-humidity exchanger comprising: a moisture permeable membrane which transmits moisture therethrough; a dry gas separator in which low-temperature dry gas is caused to flow; and a wet gas separator in which high-temperature wet gas is caused to flow, in which the moisture permeable membrane, the dry gas separator, the moisture permeable membrane, and the wet gas separator are repeatedly stacked in the stated order, wherein in the dry gas separator and the wet gas separator: a plurality of channel grooves which are divided by half in the stacking direction, are open to a direction in which the channel grooves come into contact with the moisture permeable membrane, and are arrayed parallel to one another are provided; an aggregate communication groove which is made to communicate with both end portions of the plurality of channel grooves, for aggregating gas caused to flow through the channel grooves to at least one is provided; and a supply manifold and an exhaust manifold which are made to communi

Abstract: Thin layers of a mixed composition are deposited on a porous substrate by chemical vapor deposition in an inert atmosphere at high temperature. The resulting membrane has excellent stability to water vapor at high temperatures. An exemplary membrane comprises an amorphous mixed-element surface layer comprising silica and at least one oxide of additional element, an optional porous substrate on which said surface layer is deposited, and a porous support on which said substrate or mixed-element surface layer is deposited, wherein the permeance of the membrane is higher than 1×10?7 mol m?2 s?1 Pa?1 and the selectivity of H2 over CO, CO2, and CH4 is larger than 100, and wherein the H2 permeance of the membrane after exposure to a stream containing 60 mol % water vapor at 673 K for 120 h is at least 50% of its initial H2 permeance.

Abstract: A device for use in a fluid system includes a flow perturbation element within a fluid channel. The flow perturbation element has a gas permeable surface for removing dissolved gas from passing fluid. A gas permeable membrane is coated on the gas permeable surface and allows the dissolved gas transport out of passing fluid into a gas-removal channel. The gas permeable membrane may be coated on the fuel perturbation elements using any of a variety of methods.

Abstract: A separation membrane-porous material composite 1 being improved influx and selectivity, which comprises a porous material and a separation membrane formed on the porous material, wherein a composite layer 65 having a thickness of 1 mm or less is provided at the interface between the porous material 61 as a dense layer 64 and the separation membrane 66 being formed as a carbonaceous film.

Abstract: An electrospinning fine fiber production methodology for generating a significant amount of fibers with diameters of less than 100 nanometers is provided. Also, a filter media composite comprising a substrate layer and an electrospun fine fiber layer having a increased efficiency relative to pressure drop and/or a controlled pore size distribution is provided. According to some embodiments nylon is electrospun from a solvent combination of formic and acetic acids.

Abstract: A nonporous metal carbonate membrane for selective separation of CO2 from a CO2-containing fluid having a porous substrate having a feed side and a permeate side. The membrane is also suitable for removal of H2S that may be present in the fluid.

Abstract: A membrane 12 that exhibits superior condensation resistance regardless of the type of moisture-permeable resin, that has satisfactory adhesion between a porous film and a reinforcing member, and that can be manufactured in a simple manner. The membrane 12 is a laminated article 23 containing a porous film 20 and a reinforcing member 40, and the reinforcing member 40 has a moisture-permeable resin layer 30 on the side of an interface 50 with the porous film 20. To reliably form the moisture-permeable resin layer (moisture-permeable resin film) 30, the average pore diameter of the porous film 20 is preferably 0.01 to 10 ?m, and the porosity of the reinforcing member 40 is preferably 30 to 95%. According to the membrane 12 of the present invention, even if the moisture-permeable resin is water-soluble (for example, polyvinyl alcohol), condensation resistance is still satisfactory.

Abstract: The invention relates to a method for producing a device for gas separation, said device comprising a layer system wherein a functional layer consisting of TiO2 and/or ZrO2 having an average pore diameter of less than 1 nm is applied to at least one side of a carrier layer that is porous throughout. Said carrier layer is preferably between 100 ?m and 1 mm thick and comprises continuous pores with an average pore diameter in the ?m range. The functional layer which is applied directly or by means of at least one intermediate layer comprises continuous pores with an average pore diameter of less than 1 nm, especially less than 0.8 nm. The functional layer can advantageously be embodied as a graduated layer. The invention is especially characterised by the symmetrical structure of the device, in which functional layers are applied to both sides of the carrier layer, optionally by means of respectively at least one intermediate layer.

Abstract: A fuel system for an energy conversion device includes a multiple of non-metallic fuel plates, gaskets, oxygen permeable membranes, porous substrate plates, and vacuum frame plates. Intricate 3-dimension fuel channel structures such as laminar flow impingement elements within the fuel channel dramatically enhance oxygen diffusivity in the FSU. The fuel plates are manufactured from a relatively soft non-metallic material. The non-metallic fuel plates and gasket arrangement provide an effective sealing interface between the fuel plate and oxygen permeable membrane, since compression may be applied to the plates without damaging the relatively delicate oxygen permeable membrane.

Abstract: A hydrogen separator is provided, including a porous substrate having a large number of pores communicating from a first surface to a second surface thereof, and having a hydrogen-separating layer disposed on the first surface so that the hydrogen-separating layer has a penetrated portion extending through the pores from the first surface to a particular depth. An average pore diameter at the first surface of the porous substrate is 0.02 to 0.5 ?m, a thickness of the hydrogen-separating layer is 1 to 5 ?m, and a penetration depth of the penetrated portion is 0.05 to 1 ?m, is at least equal to the average pore diameter at the one surface of the porous substrate, and is not larger than one half of the thickness of the hydrogen-separating layer. The hydrogen separator hardly generates defects such as cracks, peeling and the like in the hydrogen-separating layer, is superior in durability, and provides both good hydrogen-separating ability and good hydrogen permeability.

Abstract: There is provided a membrane material for a gas folder having abrasion resistance and flex resistance usable as a gas holder, in addition to strength of a base fabric, and having high gas barrier properties. A membrane material for a gas holder, which is used in a gas holder for storing or recovering gas, comprising at least 4 layers of a protective layer, a base fabric layer, a gas barrier layer and a protective layer laminated in this order.

Abstract: A composite oxygen ion transport membrane having a dense layer, a porous support layer, an optional intermediate porous layer located between the porous support layer and the dense layer and an optional surface exchange layer, overlying the dense layer. The dense layer has electronic and ionic phases. The ionic phase is composed of scandia doped, yttrium or cerium stabilized zirconia. The electronic phase is composed of a metallic oxide containing lanthanum, strontium, chromium, manganese and vanadium and optionally cerium. The porous support layer is composed of zirconia partially stabilized with yttrium, scandium, aluminum or cerium or mixtures thereof. The intermediate porous layer, if used, contains the same ionic and electronic phases as the dense layer. The surface exchange layer is formed of an electronic phase of a metallic oxide of lanthanum and strontium that also contains either manganese or iron and an ionic phase of scandia doped zirconia stabilized with yttrium or cerium.

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

Abstract: A gas flow generator comprising: an ultrasonic driver comprising a piezoelectric or electrostrictive transducer mounted on a substrate, operation of the transducer being arranged to cause the driver to bend; a first membrane disposed on or formed integrally with the transducer or the substrate; and a second membrane mounted substantially parallel with the driver and spaced a given distance therefrom, one of the membranes being perforate, whereby ultrasonic bending of the driver on actuation of the transducer causes a gas flow through the perforate membrane.

Abstract: A fuel system includes a fuel deoxygenator for removing oxygen from a liquid fuel. A vaporizer is in fluid communication with the fuel deoxygenator. The vaporizer vaporizes at least a portion of the liquid fuel to produce vaporized fuel. At least a portion of the vaporized fuel pre-mixes with oxidizer to reduce formation of undesirable emissions.

Abstract: The present invention discloses mixed matrix membranes (MMMs) comprising a polymer matrix and molecular sieve particles and methods for making and using these membranes. The molecular sieve particles contain micropores or mesopores and exhibit a thin plate morphology with high aspect ratio and the plate thickness no more than 300 nm. This invention also pertains to controlling the alignment of the thin plate molecular sieve particles in the continuous polymer matrix of the thin dense selective layer of the asymmetric mixed matrix membranes. These MMMs exhibited much higher selectivity improvement than those comprising molecular sieve particles with other kinds of morphology for gas separations such as CO2/CH4 and H2/CH4 separations. The thin plate morphology of molecular sieves is beneficial to make high performance mixed matrix membranes.

Abstract: A method of preparing a gas separation membrane system and the gas separation membrane system itself, wherein the method includes applying a layer of a gas-selective material to a porous substrate followed by heat-treating thereof in an inert gaseous atmosphere and then polishing and repeating these steps to thereby provide the gas separation membrane system or a structure that may suitably be used in a gas separation membrane system.

Abstract: A polyimide MMC membrane useful for the production of oxygen-enriched air or nitrogen-enriched-air, for the separation of carbon dioxide from hydrocarbons or nitrogen, and the separation of helium or hydrogen from various streams. Membranes of polyimide polymers, such as polyimide polymers sold under the tradename P-84, are mixed with molecular sieve materials, such as SSZ-13, to make MMC membranes. The MMC membranes of the invention provide improved membrane performance compared to polymer only membranes, particularly when used to form asymmetric film membranes or hollow fiber membranes. The MMC films exhibit consistent permeation performance as dense film or asymmetric membranes, and do not interact with components of the process streams, such as organic solvents. The membranes of the invention exhibit particularly surprisingly good selectivity for the fluids of interest.

Abstract: A fine particle filtration fabric, stabilized dimensionally against distension by a force field which may be applied to the fabric, has a layer of air filtration media, and a reinforcing matrix of filaments extending linearly in plural directions within a two-dimensional geometric pattern along said layer of filtration media or even outside of a composite fabric containing filtration media to inhibit the distension. The air filtration media comprises a layer of flexible lay-down of discontinuous filaments or fibers providing interstitial spacing in a range of 0.1 to 0.5 microns, the layer having a thickness in the range of 1-5 millimeters.

Abstract: A component for use in assembling a membrane electrode assembly comprises a microporous layer supported on a transfer substrate, wherein the microporous layer comprises carbon particles and a hydrophobic polymer, and a polymer layer is present on the microporous layer. A process for preparing a component for use in assembling a membrane electrode assembly includes forming the microporous layer on the transfer substrate and applying a polymer layer on the microporous layer. The microporous layer may also be deposited onto a gas diffusion substrate for use in the membrane electrode assembly.

Abstract: The subject of the present invention is a method for producing a gas separation membrane, comprising the deposition of a film from a silica sol onto a porous support followed by heat treatment of the film thus deposited, in which the silica sol deposited is prepared by hydrolysing a silicon alkoxide in the presence of a doping amount of a precursor of an oxide of a trivalent element, especially boron or aluminium. The invention also relates to the membranes as obtained by this method, and also to their uses, especially for the separation of helium or hydrogen at high temperature, and in particular for removing impurities in helium streams.

Abstract: Planar ceramic membrane assembly comprising a dense layer of mixed-conducting multi-component metal oxide material, wherein the dense layer has a first side and a second side, a porous layer of mixed-conducting multi-component metal oxide material in contact with the first side of the dense layer, and a ceramic channeled support layer in contact with the second side of the dense layer.

Abstract: A gas separator is provided, including a porous substrate made of a first ceramic and a gas-separating layer containing zeolite disposed on the surface of the porous substrate. The gas-separating layer further contains, in addition to zeolite, a thermal expansion coefficient-adjusting material made of a second ceramic having a linear thermal expansion coefficient satisfying a predetermined relationship, so that the difference between the thermal expansion coefficient of the porous substrate and the gas-separating layer can be reduced.

Abstract: The present invention includes a method, composition and apparatus for forming a nanoparticle filled polymer having similar gas selectivity and greater gas permeability than the native polymer. The nanoparticle filled polymer includes one or more polymeric materials and one or more nanoparticles dispersed within the one or more polymeric materials that increasing the permeability of the nanoparticle filled polymers relative to the permeability of the native polymer membrane.

Abstract: A reverse osmosis membrane, and methods for making and using the membrane. The membrane has a continuous, defect-free, non-porous, hydrophilic coating that reduces the susceptibility to fouling.

Abstract: There is provided a nanocomposite membrane comprising an Ag-nanoparticle/polymer nanocomposite, in which the Ag-particles are uniformly dispersed in the polymer matrix, and a support membrane for supporting the nanocomposite, as well as a process of preparing said membrane. The nanocomposite membrane of the present invention comprising a neutral Ag-nanoparticle as an olefin carrier, which is chemically stable, has excellent long-term operation performance characteristics as well as high selectivity and permeability. Thus, it can be advantageously used for the separation of olefin from an olefin/paraffin mixture.

Abstract: The present invention provides a durable liquid housing container and a durable liquid supply apparatus which use a gas-liquid separation membrane. Thus, a gas-liquid separation membrane (2) located at an air vent in a liquid housing container (1) includes a fibril portion (2A) composed of fibrous portions and an annular node portion (2B) which bundles the ends of fibrous portions of the fibril portion (2A) and which is closed so as to surround the fibril portion (2A).

Abstract: The materials of adjoining porous metal substrate (12), oxide (14), and Pd-alloy membrane (16) layers of a composite, H2—separation palladium membrane (10) have respective thermal expansion coefficients (TEC) which differ from one another so little as to resist failure by TEC mismatch from thermal cycling. TEC differences (20, 22) of less than 3 ?m/(m.k) between materials of adjacent layers are achieved by a composite system of a 446 stainless steel substrate, an oxide layer of 4 wt % yittria-zirconia, and a 77 wt % Pd-23 wt % Ag or 60 wt % Pd-40 wt % Cu, membrane, having TECs of 11, 11, and 13.9 ?m/(m.k), respectively. The Intermediate oxide layer comprises particles forming pores having an average pore sizeless than 5 microns, and preferably less than about 3 microns, in thickness.

Abstract: An Ni—Ti—Nb based multiple phase alloy consists of a combined phase which comprises a phase for the hydrogen permeability and a phase for the resistance to hydrogen embrittlement. The alloy has a composition satisfying the formula: NixTiyNb(100-x-y) in which x=25˜45 mol % and y=25˜55 mol %. A metal membrane for hydrogen separation-purification is prepared using the alloy material. The alloy material is prepared by blending Ni, Ti and Nb and melting the blend. The metal membrane permits the hydrogen separation-purification and thus the resulting purified hydrogen gas can be used as a fuel and can be applied to fields of production of semiconductors.

Abstract: Method of operating an oxygen-permeable mixed conducting membrane having an oxidant feed side, an oxidant feed surface, a permeate side, and a permeate surface, which method comprises controlling the differential strain between the permeate surface and the oxidant feed surface at a value below a selected maximum value by varying the oxygen partial pressure on either or both of the oxidant feed side and the permeate side of the membrane.

Abstract: A fuel system for an energy conversion device includes a multiple of fuel plates, oxygen permeable membranes, porous substrate plates, and vacuum frame plates which define a wave pattern configuration. The wave configuration enhances deoxygenation by increasing the efficiency and integrality due to higher surface volume ration, increase of flow turbulence, and minimal sharp edges which may otherwise damage the oxygen permeable membranes compared to other configurations.

Abstract: A fuel system for an energy conversion device includes a deoxygenator system with an oxygen permeable membrane having a textured surface. A sweep gas and/or vacuum maintains an oxygen concentration differential across the membrane to deoxygenate the fuel. The textured surface increases the surface area of the oxygen permeable membrane. The textured surface of the oxygen permeable membrane is fabricated by pressing the textured surface into the oxygen permeable membrane with a microreplication-based tooling system. Another fabrication method presses the textured surface into a sacrificial film and the oxygen permeable membrane is then formed upon the sacrificial film to transfer the textured surface to the oxygen permeable membrane and the sacrificial film is then subsequently removed. Another fabrication method applies additional material to the oxygen permeable membrane through a porous sacrificial film.

Abstract: The present invention provides systems and methods for facilitating contact between a liquid and a fluid. Such systems and methods may allow efficient removal of components from the liquid without using undesirable reducing agents. In this regard, the disclosed embodiments provide for the purification of a liquid by passing the liquid and a fluid through a porous medium. The porous medium facilitates mixing of the liquid and the fluid. A partial pressure differential of the component between the liquid and the fluid facilitates the transfer of the component from the liquid to the fluid in the mixed liquid and fluid. One embodiment of the invention relates to a method of purifying a liquid. The method includes passing a liquid, such as a fuel, and a fluid, such as a non-reactive gas, through a porous medium, the liquid containing a component, such as oxygen gas, therein. The passing causes mixing of the liquid and the fluid and transfer of at least some of the component from the liquid to the fluid.

Abstract: Solid oxide fuel cells selectively transport oxygen ions through an electrolyte membrane. The maximum oxygen ion transport rate limits the power density of the fuel cell. By ion irradiating the electrolyte membrane and/or the cathode, the oxygen adsorption, dissociation, and incorporation rates can be improved, leading to higher ion transport rates and better fuel cell performance.