Abstract: A polymer electrolyte membrane for a fuel cell includes a polymer matrix comprising a cross-linked curable oligomer with nano-sized proton conductive polymer particles in the polymer matrix. The curable oligomer may include unsaturated functional groups at each end of a chain, and may further include 3 to 14 ethylene oxides. The proton conductive polymer nano particles may include fluorine-based proton conductive polymer nano particles, non-fluorine-based proton conductive polymer nano particles, hydrocarbon-based proton conductive polymer nano particles, and combinations.

Abstract: Tubular ceramic structures of non-circular cross section, e.g., anode components of tubular fuel cells of non-circular cross section, are manufactured by applying ceramic-forming composition to the external non-circular surface of the heat shrinkable polymeric tubular mandrel component of a rotating mandrel-spindle assembly, removing the spindle from said assembly after a predetermined thickness of tubular ceramic structure of non-circular cross section has been built up on the mandrel and thereafter heat shrinking the mandrel to cause the mandrel to separate from the tubular ceramic structure of non-circular cross section.

Abstract: The present invention relates to a method for manufacturing a metal-oxide-based ceramic, including, in order, the step of inserting, into a flash sintering device, a nanocrystalline powder comprising crystallites and crystallite agglomerates of a ceramic of formula, Zr1-xMxO2, where M is chosen from yttrium, scandium and cerium, or Ce1-xM?xO2, where M? is chosen from gadolinium, scandium, samarium and yttrium, where x lies between 0 and 0.2, the powder having an average crystallite size of between 5 and 50 nm, an average crystallite agglomerate size of between 0.5 and 20 ?m, and a specific surface area of between 20 and 100 m2/g. The invention further includes the step of flash sintering the powder by applying a pressure of between 50 and 150 MPa, at a temperature of between 850° C. and 1400° C., for a time of between 5 and 30 minutes.

Abstract: A silicon-based proton exchange membrane for a membrane electrode assembly comprises a silicon wafer including a back side, a front side, and a membrane region therebetween, where the membrane region includes a plurality of channels extending from openings in the front side of the silicon wafer through the membrane region to openings in the back side of the silicon wafer. Walls of the channels include active sites to which a molecular species may be attached. Each of the front side and the back side of the silicon wafer includes a porous capping layer thereon. The capping layer comprises a plurality of through-thickness apertures contiguous with at least a portion of the channels of the membrane region.

Abstract: An electrolyte-free, oxygen-free, high power, and energy dense single fuel cell device is provided, along with methods for making and use. The fuel cell device is based on an electron-relay function using a nanostructured membrane prepared by cross-linking polymers, and having embedded within the membrane, a reactant. Use of the fuel cell device does not produce water, or CO2, and no oxygen is needed. The rechargeability of the fuel cell device revealed it can function as a portable battery.

Abstract: Provided are a solid proton conductor and a fuel cell including the solid proton conductor. The solid proton conductor includes a polymer providing a proton source, and a polymer solvent providing a proton path.

Abstract: A solid oxide fuel cell supplied with a fuel gas and an oxidant gas, including a single cell 4 having a plate-like electrolyte 41, an cathode 42 formed on an upper surface of the electrolyte 41, and a anode 43 formed on a lower surface of the electrolyte 41; a conductive support substrate 2 supporting the single cell 4, and having through-holes 21 that form a supply path for the fuel gas or oxidant gas; and a gas-permeable welding layer 3 sandwiched between the single cell 4 and the support substrate 2, and welded to the single cell 4 and the support substrate 2.

Abstract: The present invention provides solid oxide fuel cells, solid oxide electrolyzer cells, solid oxide sensors, components of any of the foregoing, and methods of making and using the same. In some embodiments, a solid oxide fuel cell comprises an air electrode (or cathode), a fuel electrode (or anode), an electrolyte interposed between the air electrode and the fuel electrode, and at least one electrode-electrolyte transition layer. Other embodiments provide novel methods of producing nano-scale films and/or surface modifications comprising one or more metal oxides to form ultra-thin (yet fully-dense) electrolyte layers and electrode coatings. Such layers and coatings may provide greater ionic conductivity and increased operating efficiency, which may lead to lower manufacturing costs, less-expensive materials, lower operating temperatures, smaller-sized fuel cells, electrolyzer cells, and sensors, and a greater number of applications.

Abstract: Disclosed is a fuel cell in which a membrane electrode assembly less undergoes increase in ion conduction resistance, and a polymer electrolyte membrane less undergoes deterioration. Specifically, the polymer electrolyte membrane includes a first membrane and a second membrane being two different membranes composed of polymer electrolytes having different ion-exchange capacities, in which the first membrane has an area of one surface thereof equal to or larger than an area of one surface of an anode or a cathode, and the second membrane has an area of one surface thereof smaller than that of the first membrane and is arranged in a gas inflow region on a side being in contact with the cathode. The second membrane has an ion-exchange capacity smaller than that of the first membrane or has a number-average molecular weight larger than that of the first membrane.

Abstract: A composition for filling an ion exchange membrane including a first aromatic vinyl monomer having a halogenated alkyl group or a quaternary ammonium salt group, a method of preparing the ion exchange membrane, an ion exchange membrane prepared using the method, and a redox flow battery including the ion exchange membrane.

Abstract: First, second and third dopes each of which contains a solid electrolyte and an organic solvent are cast from a casting die provided with a feed block to a moving belt. A three-layer casting membrane is peeled off from the belt as a three-layer membrane containing the organic solvent. After being dried in a tenter device, the membrane still containing the organic solvent is contacted with a liquid which is a poor solvent of the solid electrolyte and having lower boiling point than the organic solvent. Thereafter, the membrane is transported to a drying chamber and dried while being supported by the plural rollers.

Abstract: An electrolyte membrane (1) includes a base material layer (1) containing a hydrocarbon-based electrolyte as a main component, and a surface layer (5) laminated with the base material layer (1). The surface layer (5) is a layer containing, as a main component, a polymeric material having a hydroxyl group and a proton conductive group. The polymeric material that constitutes the surface layer (5) contains, for example, a first polymer having a hydroxyl group, and a second polymer having a proton conductive group. A matrix is formed by cross-linking the first polymer, and the second polymer can be held in the matrix.

Abstract: Crosslinked sulfonated triblock copolymers exhibit lower methanol permeability and good physical strength relative to the perfluorinated proton conductive membranes typically used in Direct Methanol Fuel Cells. Examples of triblock copolymers that can be used as fuel cell membranes include SEBS, SIBS, and SEPS. The chemically cross-linked and sulfonated SIBS, SEBS, and SEPS exhibit lower swelling and tolerate higher sulfonation levels than the un-cross-linked counterparts. These copolymers are easily sulfonated using known procedures and can be manufactured at a fraction of the cost of the typical perfluorinated proton conductive membranes.

Abstract: There are provided a novel proton-conducting polymer membrane that shows good workability in a fuel cell assembling process and good proton conductivity and durability even under high-temperature, non-humidified conditions, a method for production thereof, and a fuel cell therewith. The proton-conducting polymer membrane includes: a polymer membrane containing a polybenzimidazole compound having a sulfonic acid group and/or a phosphonic acid group; and vinylphosphonic acid contained in the polymer membrane. The fuel cell uses the proton-conducting polymer membrane. The polybenzimidazole compound preferably includes a sulfonic and/or phosphonic acid group-containing component represented by Structural Formula (1): wherein n represents an integer of 1 to 4, R1 represents a tetravalent aromatic linking unit capable of forming an imidazole ring, R2 represents a bivalent aromatic linking unit, and Z represents a sulfonic acid group and/or a phosphonic acid group.

Abstract: The present invention easily provides a polymer electrolyte that exhibits high proton conductivity under low humidity conditions and has a high level of durability and mechanical strength. The polymer electrolyte is produced by mixing proton-conducting sulfonated polyethersulfone C1, sulfonated polyphenylene sulfide C2 or sulfonated poly(4-phenoxybenzoyl-1,4-phenylene) C3 having a sulfonic acid group A as a protic acid group with 1,4-benzenedimethanol B as a crosslinking agent having a methylol group and heat-treating the mixture so that a reaction can be carried out. The polymer electrolyte includes a plurality of proton-conducting sulfonated polyethersulfone moieties C chemically bonded at their aromatic ring moieties other than the sulfonic acid group A to one another through a residue B? of 1,4-benzenedimethanol.

Abstract: An inorganic ion conductor including a trivalent metallic element, a pentavalent metallic element, phosphorus, and oxygen.

Abstract: A fuel cell includes membrane electrode assemblies disposed in a planar arrangement. Each membrane electrode assembly includes an electrolyte membrane, an anode catalyst layer, and a cathode catalyst layer disposed counter to the cathode catalyst via the electrolyte membrane. Interconnectors (conductive members) are provided on the lateral faces of the electrolyte membranes disposed counter to each another in the neighboring direction of the membrane electrode assemblies. Each interconnector includes a support portion protruding toward the central region of the electrolyte member on the cathode side of the electrolyte membrane. The support portion is in contact with the cathode-side surface of an edge of the electrolyte membrane, and the electrolyte membrane is held by the support portion.

Abstract: A proton-conducting structure that exhibits favorable proton conductivity in the temperature range of not lower than 100° C., and a method for manufacturing the same are provided. After a pyrophosphate salt containing Sn, Zr, Ti or Si is mixed with phosphoric acid, the mixture is maintained at a temperature of not less than 80° C. and not more than 150° C., and thereafter maintained at a temperature of not less than 200° C. and not more than 400° C. to manufacture a proton-conducting structure. The proton-conducting structure of the present invention has a core made of tin pyrophosphate, and a coating layer formed on the surface of the core, the coating layer containing Sn and O, and having a coordination number of O with respect to Sn of grater than 6.

Abstract: The present invention provides a catalytic layer-electrolytic membrane laminate for an unhumidified-type fuel cell, comprising an electrolytic membrane containing a strong acid; a conductive layer formed on one surface or both surfaces of the electrolytic membrane; and a catalytic layer formed on the conductive layer; wherein the conductive layer is formed of a fluorine-containing resin and carbon powder, and the conductive layer is thinner than the electrolytic membrane. The present invention provides a catalytic layer-electrolytic membrane laminate for an unhumidified-type fuel cell that can be practically used.

Abstract: A laminated electrolyte membrane, a membrane electrode assembly including the laminated electrolyte membrane, and a method of preparing the laminated electrolyte membrane, the laminate electrolyte membrane comprising at least two polymer membranes that are laminated together, and an electrolytic polymer obtained by polymerizing a monomer having a polymerizable functional group and a proton dissociable functional group.

Abstract: A compound including a cage-type structure of silsesquioxane wherein a group represented by Formula 1 or a salt thereof is directly linked to at least one silicon atom of the silsesquioxane, a composition including the compound, a composite formed therefrom, electrodes and an electrolyte membrane that include the composite, a method of preparing the compound, and a fuel cell including the electrodes and the electrolyte membrane. wherein in Formula 1, n is 1 or 2.

Abstract: A solid oxide fuel cell stack obtainable by a process comprising the use of a glass sealant with composition 50-70 wt % SiO2, 0-20 wt % Al2O3, 10-50 wt % CaO, 0-10 wt % MgO, 0-6 wt % (Na2O+K2O), 0-10 wt % B2O3, and 0-5 wt % of functional elements selected from TiO2, ZrO2, F, P2O5, MoO3, Fe2O3, MnO2, La. Sr—Mn—O perovskite (LSM) and combinations thereof.

Abstract: A polymer electrolyte membrane (PEM) for fuel cells is provided, as well as a method for manufacturing the PEM by direct casting on the fuel cells electrodes. The PEM, consisting of an ionic liquid entrapped within polysiloxane-RTV matrix, is stable at high temperatures, in acidic and basic environments, and exhibits a high conductivity, without the crossover of methanol.

Abstract: A redox fuel cell comprising an anode and a cathode separated by an ion selective polymer electrolyte membrane; means for supplying a fuel to the anode region of the cell; means for supplying an oxidant to the cathode region of the cell; means for providing an electrical circuit between the anode and the cathode; a catholyte solution comprising a modified ferrocene species being at least partially reduced at the cathode in operation of the cell, and at least partially re-generated by reaction with the oxidant after such reduction at the cathode.

Abstract: The present invention relates to a polymer blend proton exchange membrane comprising a soluble polymer and a sulfonated polymer, wherein the soluble polymer is at least one polymer selected from the group consisting of polysulfone, polyethersulfone and polyvinylidene fluoride, the sulfonated polymer is at least one polymer selected from the group consisting of sulfonated poly(ether-ether-ketone), sulfonated poly(ether-ketone-ether-ketone-ketone), sulfonated poly(phthalazinone ether ketone), sulfonated phenolphthalein poly (ether sulfone), sulfonated polyimides, sulfonated polyphosphazene and sulfonated polybenzimidazole, and wherein the degree of sulfonation of the sulfonated polymer is in the range of 96% to 118%. The present invention further relates to a method for manufacturing the polymer blend proton exchange membrane.

Abstract: A method of enhancing electrical performance of a membrane for a fuel cell is disclosed. The method includes providing a perfluorosulfonic acid (PFSA) ionomer in an aqueous hydroxylated hydrocarbon aqueous solution. The PFSA dispersion or solution has an acid number the same or higher than an acid number of the membrane. The membrane is immersed in the solution such that the high acid number PFSA dispersion diffuses into the membrane. After immersion, the removed membrane is then dried under tension.

Abstract: A membrane electrode assembly includes an electrolyte membrane, anode catalyst layers, and cathode catalyst layers provided counter to the anode catalyst layers, respectively. An insulating layer is provided on the electrolyte membrane between adjacent anode catalyst layers. An insulating layer is provided on the electrolyte membrane between adjacent cathode catalyst layers. The resistivity of the insulating layer is preferably identical to or higher than that of the electrolyte membrane.

Abstract: A novel ion conductive material is provided. The ion conductive material composed of an amorphous material is employed.

Abstract: An ion-conductive polymer composite membrane is provided which has both high gas barrier properties and high protonic conductivity. The ion-conductive polymer composite membrane includes an ion-conductive polymer and ion-conductive materials. The ion-conductive materials each include i) an inorganic layered structure including a plurality of layers formed of an inorganic compound and ii) a sulfobetaine-type or hydroxysulfobetaine-type ampholytic surfactant. The ampholytic surfactant is present between the layers formed of an inorganic compound. The present invention further provides a membrane-electrode assembly and a fuel cell which use the ion-conductive polymer composite membrane, and a process for producing the ion-conductive polymer composite membrane.

Abstract: An anode component of a solid oxide fuel cell is formed by combining a relatively coarse yttria-stabilized-zirconium (YSZ) powder, that is substantially composed of elongated particles, with a relatively fine NiO/YSZ or NiO powder of reduced particle size, whereby, upon sintering the combined powders, the coarse YSZ powder forms a microstructural cage of open porosity wherein the fine powder is distributed through the open porosity of the cage. A method of forming a cathode component includes combining a coarse YSZ powder, that is substantially composed of elongated particles, with a fine lanthanum strontium manganite powder of reduced particle size, whereby, upon sintering the combined powders, the coarse YSZ powder forms a microstructural cage of open porosity, wherein the fine powder is distributed through the open porosity of the cage.

Abstract: The present invention relates to a polymer electrolyte that provides high proton conductivity and low fuel crossover at the same time, as well as a member using the same. The embodiments of the invention can achieve high output and high energy density in the form of a polymer electrolyte fuel cell. A polymer electrolyte comprising a proton conductive polymer (A) and a polymer (B) which is different from (A) wherein a ratio of the amount of unfreezable water, represented by formula (S1), in said polymer electrolyte is no less than 40 wt % and no greater than 100 wt % is disclosed. The ratio of amount of unfreezable water (S1)=(amount of unfreezable water)/(amount of low melting point water+amount of unfreezable water)×100 (%).

Abstract: A membrane electrode assembly for a solid electrolyte fuel cell comprises: an electrode having a layer of nano-structured material on one of its faces, an electrocatalyst deposited on the nano-structured material and an electrolyte deposited on the electrocatalyst/nano-structured material. The nano-structured material can comprise carbon, silicon, graphite, boron, titanium and be in the form of multi-walled nano-tubes (MWNTs), single-walled nano-tubes (SWNTs), nano-fibers, nano-rods or a combination thereof. The nano-structured material can be grown or deposited on one face of an electrode of the cell or on a substrate such as a flexible sheet material of carbon fibers using chemical vapor deposition. The electrocatalyst and electrolyte can be incorporated in the nano structured material using physical vapor deposition (PVD), ion beam sputtering or molecular beam epitaxy (MBE).

Abstract: An electrochemical or electric layer system, having at least two electrode layers and at least one ion-conducting layer disposed between two electrode layers. The ion-conducting layer has at least one ion-conducting solid electrolyte and at least one binder at grain boundaries of the at least one ion-conducting solid electrolyte for improving the ion conductivity over the grain boundaries and the adhesion of the layers.

Abstract: A novel method of altering extruded membrane films for PEM (polymer electrolyte membrane) fuel cells in such a manner that the membrane films swell substantially uniformly in both the in-plane x and y directions when immersed in water or ionomer solution is disclosed. The invention includes cutting a membrane film from an extruded membrane sheet in a diagonal orientation with respect to the membrane process direction of the membrane sheet. The membrane film exhibits reduced internal stress as compared to conventionally-prepared membrane films and allows a more even distribution of pressure in a fuel cell stack, thereby reducing the incidence of swollen membrane-induced failure mechanisms in the fuel cell stack.

Abstract: Proton conductivity has been shown in acceptor-doped rare earth orthoniobates and tantalates (LnNbO4 and LnTaO4) at high temperatures and in a humid atmosphere. The use of the materials as an electrolyte in a laboratory-scale fuel cell and water vapor sensor has been demonstrated. Results for Ca-doped LaNbO4 are given as examples.

Abstract: A polymer electrolyte membrane comprises at least one layer of a perforated sheet having many through-holes formed substantially parallel to the thickness direction with an average cross-sectional area per hole ranging from 1×10?3 to 20 mm2, wherein the numerical aperture based on the through-holes ranges from 30 to 80%, and the through-holes are filled with an ion exchange resin.

Abstract: A fuel cell system includes a fuel cell, a cathode supply passage, a cathode discharging passage, an anode supply passage, an anode discharging passage, a pair of cathode shutoff units, an anode shutoff unit, an anode discharging unit, a discharged gas processing unit, and a control unit. The control unit releases the sealing of the cathode passage by the pair of cathode shutoff units, at the time of start-up of the fuel cell system, and releases the sealing of the anode passage by the anode discharging unit, thereby performing a purge process to allow discharge of the anode gas.

Abstract: An ion conducting membrane for fuel cell applications includes an ion conducting polymer and a porphyrin-containing compound at least partially dispersed within the ion conducting polymer. The ion conducting membranes exhibit improved performance over membranes not incorporating such porphyrin-containing compounds.

Abstract: Provided is a varnish which contains a solvent and an electrode electrolyte for a solid polymer fuel cell electrolyte, which contains a polymer with a structure having a main chain including a polyphenylene, a side chain including a sulfonic acid group and a repeating structural unit as a side chain including a nitrogen-containing heterocyclic group.

Abstract: A free-standing membrane electrolyte electrode assembly (ESC) comprises an electrolyte, an anode electrode formed at one end face of the electrolyte, and a cathode electrode formed at the other. The electrolyte is a single crystal having a surface along with oxide ions move or a direction in which the ions move or a polycrystal oriented along a surface along which oxide ions move or in a direction in which the ions move. The surface or the direction is parallel to the thickness direction. The thickness of the electrolyte is 50 to 800 ?m and the quotient of the division of the total thickness of the anode electrode and the cathode electrode by the thickness of the electrolyte is 0.1 or less,. The thickness of the ESC is 1 mm or less.

Abstract: A polymer membrane composition for a fuel cell, a polymer membrane prepared therefrom, a membrane electrode assembly, a fuel cell including the same, and associated methods, the polymer membrane composition including a polymer, the polymer including a cation exchange group and a carbon double-bond-containing cross-linkable group, a (meth)acryl-based compound, the (meth)acryl-based compound including a cation exchange group, and a polymerization initiator.

Abstract: A vinyl monomer is graft polymerized on an aromatic hydrocarbon-based polymer film substrate to introduce graft chains into the substrate and thereafter a functional monomer represented by the following formula and having sulfonic acid groups or functional groups capable of conversion to sulfonic acid groups is graft polymerized to introduce the sulfonic acid groups or the functional groups capable of conversion to sulfonic acid groups: where R is an aromatic ring or an aliphatic chain; X is (1) —OH, (2) —OLi, —ONa or —OK, (3) —F or —Cl, or (4) —OCnH2n+1 where n is an integer of 1 to 7. Since the graft chains obtained by graft polymerization of the vinyl monomer can also be utilized as scaffold polymers, the graft polymerizability of the functional monomer to the aromatic hydrocarbon-based polymer film substrate is sufficiently improved to enable the preparation of a polymer electrolyte membrane that excels not only in proton conductivity and mechanical strength but also in dimensional stability.

Abstract: Active metal fuel cells are provided. An active metal fuel cell has a renewable active metal (e.g., lithium) anode and a cathode structure that includes an electronically conductive component (e.g., a porous metal or alloy), an ionically conductive component (e.g., an electrolyte), and a fluid oxidant (e.g., air, water or a peroxide or other aqueous solution). The pairing of an active metal anode with a cathode oxidant in a fuel cell is enabled by an ionically conductive protective membrane on the surface of the anode facing the cathode.

Abstract: A fuel cell has a gas diffusion layer (15A, 15C) provided on at least one surface side of a polymer electrolyte membrane (12). The polymer electrolyte membrane is structured with a conductive carbon sheet. Fluid flow passages (16A, 16C) are formed on the surface of the gas diffusion layer (15A, 15C) contacting a separator (21A, 21C). The roughness of the surface of the gas diffusion layer (15A, 15C) provided with the fluid flow passage is smaller than the roughness of its surface contacting the catalyst layer (14A, 14C). Thus, it becomes possible to achieve a further improvement in power generation performance, and to suppress a reduction in durability.

Abstract: The present invention provides a method for manufacturing an electrode catalyst layer for a fuel cell which includes a polymer electrolyte, a catalyst material and carbon particles, wherein the electrode catalyst layer employs a non-precious metal catalyst and has a high level of power generation performance. The electrode catalyst layer is used as a pair of electrode catalyst layers in a fuel cell in which a polymer electrolyte membrane is interposed between the pair of the electrode catalyst layers which are further interposed between a pair of gas diffusion layers. The method of the present invention has such a feature that the catalyst material or the carbon particles are preliminarily embedded in the polymer electrolyte.

Abstract: A crosslinked object of a polybenzoxazine-based compound formed of a polymerized resultant of a first monofunctional benzoxazine-based monomer or a second multifunctional benzoxazine-based monomer with a crosslinkable compound, an electrolyte membrane including the crosslinked object, a method of preparing the electrolyte membrane, and a fuel cell employing the electrolyte membrane including the crosslinked object.

Abstract: A solid state electrochemical cell comprises a dense electrolyte layer; at least one reticulated electrode matrix (REM) of ion-conducting material partially sintered on the gas impermeable electrolyte layer, and electrode material located substantially within the REM. The REM has a majority of pores with an average pore size of less than micron. The REM can also have a porosity of 5 to 80%, thickness at or below 3.00 microns, and a mean grain size of 0.01 to 3.00 microns.

Abstract: The invention relates to membrane-electrode assemblies for the electrolysis of water (electrolysis MEAs), which contain an ion-conducting membrane having a front and rear side; a first catalyst layer on the front side; a first gas diffusion layer on the front side; a second catalyst layer on the rear side, and a second gas diffusion layer on the rear side. The first gas diffusion layer has smaller planar dimensions than the ion-conducting membrane, whereas the second gas diffusion layer has essentially the same planar dimensions as the ion-conducting membrane (“semi-coextensive design”). The MEAs also comprise an unsupported free membrane surface that yields improved adhesion properties of the sealing material. The invention also relates to a method for producing the MEA products. Pressure-resistant, gastight and cost-effective membrane-electrode assemblies are obtained, that are used in PEM water electrolyzers, regenerative fuel cells or in other electrochemical devices.

Abstract: A membrane-electrode assembly for a fuel cell of the present invention includes a polymer electrolyte membrane with a layer of inorganic fine particles on either side. Catalyst layers are positioned on the layers of inorganic fine particles with gas diffusion layers positioned on the catalyst layers. The resulting polymer electrolyte membrane provides improved cell efficiency.

Abstract: A fuel cell including an electrolyte membrane and/or an electrode which includes a crosslinked polybenzoxazine-based compound formed of a polymerized product of at least one selected from a first benzoxazine-based monomer and second benzoxazine-based monomer, the first benzoxazine-based monomer and second benzoxazine-based monomer having a halogen atom or a halogen atom-containing functional group, crosslinked with a cross-linkable compound.