Abstract: A reactor includes an essentially horizontal cylinder for carrying out an autothermal gas-phase dehydrogenation of a hydrocarbon-comprising gas stream using an oxygen-comprising gas stream to give a reaction gas mixture over a heterogeneous catalyst configured as monolith. The interior of the reactor is divided by a detachable, cylindrical or prismatic housing, which is arranged in the longitudinal direction of the reactor and is gastight in the circumferential direction, into an inner region having one or more catalytically active zones, each having a packing composed of monoliths stacked on top of one another, next to one another and behind one another and before each catalytically active zone in each case a mixing zone having solid internals are provided and into an outer region, which is supplied with an inert gas, arranged coaxially to the inner region. A heat exchanger is connected to the housing at one end of the reactor.

Abstract: Embodiments of a continuous-flow injection reactor and a method for continuous material synthesis are disclosed. The reactor includes a mixing zone unit and a residence time unit removably coupled to the mixing zone unit. The mixing zone unit includes at least one top inlet, a side inlet, and a bottom outlet. An injection tube, or plurality of injection tubes, is inserted through the top inlet and extends past the side inlet while terminating above the bottom outlet. A first reactant solution flows in through the side inlet, and a second reactant solution flows in through the injection tube(s). With reference to nanoparticle synthesis, the reactant solutions combine in a mixing zone and form nucleated nanoparticles. The nucleated nanoparticles flow through the residence time unit. The residence time unit may be a single conduit, or it may include an outer housing and a plurality of inner tubes within the outer housing.

Abstract: Novel methods of electroless plating are described. Catalyst coatings can be applied within microchannel apparatus. Various reactions, including combustion and steam reforming, can be conducted over electroless catalyst coatings.

Abstract: A method and apparatus for converting natural gas from a source, such as a wellhead, pipeline, or a storage facility, into hydrocarbon liquid stable at room temperature, comprising a skid or trailer mounted portable gas to liquids reactor. The reactor includes a preprocessor which desulfurizes and dehydrates the natural gas, a first stage reactor which transforms the preprocessed natural gas into synthesis gas, and a liquid production unit using a Fischer-Tropsch or similar polymerization process. The hydrocarbon liquid may be stored in a portable tank for later transportation or further processed on site.

Abstract: Process for degrading organic substances in an aqueous composition comprising a step (a) wherein, in a liquid reaction medium, said aqueous composition is reacted with at least one composition comprising hydroxide ions (OH?) and hypochlorite in a molar ratio between hydroxide and hypochlorite higher than or equal to 0.001 and lower than 1.5, in order to oxidize said organic substances.

Abstract: Herein disclosed is a method for coal liquefaction comprising: supersaturating a hydrocarbonaceous liquid stream in a high shear device with a gas stream comprising hydrogen and optionally one or more C1-C6 hydrocarbons to form a supersaturated dispersion; and contacting the supersaturated dispersion with coal in the high shear device or in a coal liquefaction reactor to generate a product stream. In some embodiments, the method further comprises utilizing a conversion catalyst, wherein the catalyst is provided as a slurry, a fluidized bed, or a fixed bed. In some embodiments, the method further comprises feeding a conversion catalyst into the high shear device. In some embodiments, the method further comprises recycling at least a portion of an off gas from the reactor, recycling at least a portion of the product stream from the reactor, or both. Herein also disclosed is a system for coal liquefaction.

Abstract: Apparatus to produce carbon nanotubes (CNTs) of arbitrary length using a chemical vapor deposition (CVD) process reactor furnace is described, where the CNTs are grown axially along a portion of the length of the furnace. The apparatus includes a spindle and a mechanism for rotating the spindle. The spindle located within a constant temperature region of the furnace and operable to collect the CNT around the rotating spindle as the CNT is grown within the furnace.

Abstract: Herein disclosed is a method for catalytic cracking or reforming of hydrocarbons comprising: supersaturating a hydrocarbonaceous liquid or slurry stream in a high shear device with a gas stream comprising one or more C1-C6 hydrocarbons and optionally hydrogen to form a supersaturated dispersion; introducing the supersaturated dispersion into a catalytic cracking or reforming reactor in the presence of a cracking or reforming catalyst to generate a product stream. In some embodiments, the catalyst is present as a slurry or a fluidized or fixed bed of catalyst. In some embodiments, the cracking or reforming catalyst is mixed with the hydrocarbonaceous liquid or slurry stream and the gas stream in the high shear device. Herein also disclosed is a system for catalytic cracking or reforming of hydrocarbons.

Abstract: Herein disclosed is a method for thermal cracking or steam cracking of hydrocarbons comprising: supersaturating a hydrocarbonaceous liquid or slurry stream in a high shear device with a gas stream comprising steam or hydrogen and optionally one or more C1-C6 hydrocarbons to form a supersaturated dispersion; and introducing the supersaturated dispersion into a thermal cracking or steam cracking reactor to generate a product stream. In some embodiments, the method further comprises contacting the supersaturated dispersion with a cracking catalyst in a slurry, a fluidized catalyst bed, or a fixed catalyst bed. In some embodiments, the cracking catalyst is mixed with the hydrocarbonaceous liquid or slurry stream and the gas stream in the high shear device. Herein also disclosed is a system for thermal cracking or steam cracking of hydrocarbons.

Abstract: Nanoparticles as described herein are configured to bind to bacterial contaminants, such as Gram positive bacteria, Gram negative bacteria, and endotoxins. The nanoparticles include a core comprising a magnetic material; and a plurality of ligands attached to the core. The ligands include, for example, bis(dipicolylamine) (“DPA”) coordinated with a metal ion, e.g., Zn2+ or Cu2+, to form, e.g., bis-Zn-DPA or bis-Cu-DPA, which can bind to the bacterial contaminants. The nanoparticles can be included in compositions for use in methods and systems to separate bacterial contaminants from liquids, such as liquids, such as blood, e.g., whole or diluted blood, buffer solutions, albumin solutions, beverages for human and/or animal consumption, e.g., drinking water, liquid medications for humans and/or animals, or other liquids.

Abstract: Herein disclosed is a method for hydrogenation comprising: supersaturating a hydrocarbonaceous liquid or slurry stream in a high shear device with a gas stream comprising hydrogen and optionally one or more C1-C6 hydrocarbons to form a supersaturated dispersion; and introducing the supersaturated dispersion into a reactor in the presence of a hydrogenation catalyst to generate a product stream. In some embodiments, the catalyst is present as a slurry or a fluidized or fixed bed of catalyst. In some embodiments, the hydrogenation catalyst is mixed with the hydrocarbonaceous liquid or slurry stream and the gas stream in the high shear device. In some embodiments, the method further comprises recycling at least a portion of an off gas from the reactor, recycling at least a portion of the product stream from the reactor, or both. Also disclosed herein is a system for hydrogenation.

Abstract: A process of treating hydrogen gas liberated from the acid or alkaline dissolution of a metal is provided. The process comprises a step of passing the liberated hydrogen gas through a reactor containing an oxidizing agent for oxidation of the hydrogen gas into water, followed by a step of regenerating the oxidizing agent. Also provided is an apparatus for carrying out the process, the apparatus comprising a reactor containing the oxidizing agent, wherein the reactor is at least partially immersed in an alumina bath.

Abstract: The invention relates to a reactor for carrying out an exothermic reaction in the gas phase, which comprises a vessel having an outer wall (13) composed of a metallic material, wherein an inner shell (17) is accommodated in the interior of the reactor (1) and the inner shell (17) has a spacing of at least 50 mm to the inside of the outer wall (13).

Abstract: Methods and systems for preparing catalyst, such as chromium catalysts, are provided. The valence of at least a portion of the catalyst sent to an activator is changed from Cr(III) to Cr(VI). The catalyst is prepared or activated continuously using a fluidization bed catalyst activator.

Abstract: A non-woven fabric reacting with a liquid to generate gas fuel is provided. The non-woven fabric includes a plurality of core-sheath fibers, and each of the core-sheath fibers includes a core layer, a sheath layer, and a plurality of solid particles. The core layer has a first melting point. The sheath layer wraps the core layer and has a second melting point, wherein the first melting point is higher than the second melting point. The solid particles are combined to each of the sheath layers. Moreover, a method for fabricating the non-woven fabric, a gas fuel generation device using the non-woven fabric, and a method for generating the gas fuel are also provided.

Abstract: A system for devulcanizing rubber by contacting vulcanized rubber with a turpentine liquid in a reaction mixture in the absence of an alkali metal.

Abstract: A reactor for carrying out catalytic reactions. The reactor includes a reactor component optionally arranged on a central rod in a reactor tube. The reactor component can have fluid ducts for directing fluid flow through the reactor. The fluid ducts are effective for increasing heat transfer in the reactor. The reactor component can further have a washer attached to a top or bottom surface for directing fluid flow.

Abstract: The present invention discloses an apparatus for thermally refining phosphorus. The apparatus comprises: a melting furnace for melting rock phosphate into melts, including a feed port and a melt outlet; and a reduction-oxidation furnace including a furnace body which gas a melt inlet, a slag outlet, and a fume outlet, and a blow gun, wherein the melt inlet and the melt outlet are in communication with each other and wherein the blow gun has an end inserted into the furnace body. The content of impurities in fumes containing phosphorus pentaoxide is low, and the phosphorus pentaoxide can be easily extracted with a high purity of the phosphorus pentaoxide and at low cost by means of the apparatus for thermally refining phosphorus according to the present invention.

Abstract: Carbon nanotubes are grown by supplying raw material gas 30 comprising a carbon compound to be a raw material of the carbon nanotubes into the inside of a reaction vessel tube 14 in which a catalyst 26 to grow the carbon nanotubes is charged. At this time, halogen-containing material gas 32 to reduce the amount of a carbon product such as amorphous carbon produced besides carbon nanotubes that deposits on the surface of catalyst particles 44 due to supply of the raw material gas 30 is further supplied into the inside of the reaction vessel tube 14. Thereby, it is possible to produce elongated carbon nanotubes.

Abstract: The present invention relates to a method and apparatus for intensifying the energy content of an organic material by converting the material into hydrocarbons and the resulting product thereof. A method for converting an organic material into hydrocarbon fuels is disclosed. The method comprising the steps of pressurising said organic material being in a fluid to a pressure above 225 bar, heating said organic material in said fluid to a temperature above 200 C in the presence of a homogeneous catalyst comprising a compound of at least one element of group IA of the periodic table of elements. The disclosed method further comprises the steps of contacting said organic material in said fluid with a heterogeneous catalyst comprising a compound of at least one element of group IVB of the periodic table and/or alpha-alumina assuring that said fluid has initially a pH value of above 7.

Abstract: A system includes a slag additive slurry feed system configured to combine a slurrying agent, a mineral slag additive, and a liquid slurrying medium to generate a stabilized mineral slurry. The slurrying agent is configured to increase a viscosity of the stabilized mineral slurry. The system also includes a partial oxidation system configured to receive the stabilized mineral slurry, a feedstock, and oxygen into a gasifier reaction chamber. The partial oxidation system is configured to partially oxidize the feedstock to produce a gaseous product and a solid product.

Abstract: Device for the neutralization and disposal of unused human or animal pharmaceutical medicament. The device comprises a disposal device material that contains one or more disposal device agents. The disposal device material may also contain additional components to promote mixing, or neutralization of the active agent of the medicament. The disposal device material can be in the form of pellets, beads, beadlets, granules, or the like, and can be incorporated into a disposal device reservoir. The disposal device can be dispensed with a medicament, and the device can be used when the patient has finished using the medicament and there is material left over for disposal.

Abstract: The present invention relates to a micro-channel reactor for producing synthetic natural gas, and more particularly, to a micro-channel reactor for producing synthetic natural gas containing methane gas from synthetic gas, including a porous nickel plate catalyst part.

Abstract: A hydrogen gas generating apparatus for providing hydrogen gas to a fuel cell stack is provided. The apparatus includes an expandable reaction chamber containing a solid reactant component and a collapsible receptacle containing a liquid reactant component with a housing. The reaction chamber includes an expandable reactant zone defined by a moveable partition that retains the reactants and reaction products within the reaction chamber. The apparatus also includes a liquid transport control system and a fluid path for transporting the liquid reactant component from the collapsible receptacle to the reactant zone in the reaction chamber, where the liquid and solid reactant components react to generate hydrogen gas. The receptacle collapses with a corresponding expansion of the reaction chamber as liquid reactant component is used, and the reactant zone expands within the reaction chamber in response to pressure from the increasing volume of reaction products on the moveable partition.

Abstract: The present disclosure relates to a reducing method of carbon dioxide using sunlight and hydrogen, and an apparatus therefor.

Abstract: The invention relates to a method for reducing aerosol emissions from a urea granulation plant with a recovery of the resulting scrubber bleeds, with a granulator producing urea from a concentrated urea solution and an evaporation of the included water, giving urea granulates and an exhaust of dust, ammonia and ammonium cyanate, and a following scrubbing or removing stage for the dust, and a following scrubbing acid stage, resulting in a first stream comprising mainly aerosols and a second stream comprising ammonium salts, and a following aerosol stage with spray and collection devices, releasing a first stream of an exhaust of air, and a second stream of ammonium cyanate and water, and the second stream of the aerosol stage of ammonium cyanate and water is recovered into the urea granulation plant or into a urea fertilizer plant.

Abstract: Some embodiments of the present invention provide components for a serpentine fluid reactor which is optimized for one or more objective functions of interest such as pressure drop, erosion rate, fouling, coke deposition and operating costs. The components are designed by computer modeling the components individually and collectively in which the cross section of flow path is substantially circular under industrial conditions to validate the model design and its operation. Then iteratively the component designs are deformed and the operation of the deformed part(s) is modeled and compared to values obtained with other deformed models until the value of the objective function is optimized (e.g. at an extreme) or the change in the objective function is approaching zero.

Abstract: Granular crystalline silicotitanate (CST) is supplied from an adsorbent raw material supply apparatus into a caustic treatment apparatus. A sodium hydroxide solution of 1 Mol/L in a caustic agent supply apparatus is supplied into the caustic treatment apparatus with the granular CST supplied. After a predetermined quantity of the sodium hydroxide solution is supplied to the caustic treatment apparatus, the supply of the sodium hydroxide solution to the caustic treatment apparatus is stopped. The granular CST is left to stand for 0.5 hour in the state that it is immersed in the sodium hydroxide solution in the caustic treatment apparatus and is subjected to the caustic treatment. After that, the granular CST subjected to the caustic treatment is cleaned by cleaning water in a cleaning water supply apparatus. The respective adsorptive performances of cesium and strontium of the granular CST subjected to the caustic treatment are improved more.

Abstract: A method for reducing fecal coliforms in waste water wherein the flow of water is directed through a reactor having removable cover, inlet and outlet, two UV lamps, six irradiating chambers, each interconnected by apertures, a UV lamp control box, and a heat a conducting pipe to transfer heat from the control box into the flowing water.

Abstract: A fuel reformer includes a feedstream delivery unit and a catalytic reactor. The feedstream delivery unit is configured to receive reactants and to provide the reactants to the catalytic reactor. The reformer further includes a flame arrestor disposed between the feedstream delivery unit and the catalytic reactor, and at least one spacer disposed between the feedstream delivery unit and the catalytic reactor, wherein the spacer is configured to allow the reactants to flow therethrough while inhibiting thermal radiation therethrough. In a further aspect, the surfaces of the feedstream delivery unit that come into contact with the reactants in use include coatings that eliminate catalytic reactions of the feedstream within the feedstream delivery unit.

Abstract: A process for forming toner using an emulsion/aggregation scheme wherein particle aggregation occurs in a batch reactor and coalescence occurs in a continuous reactor. In embodiments, a continuous reactor comprises four sections joined in series.

Abstract: A tube reactor having a substantially tubular body portion including a conical section, an entry port, an opposing exit port, and an axis extending between the ports through the body portion. The tubular body portion being rotatable about the axis. At least one reactant can be fed into the tubular body portion and directed toward the conical section. An inner surface of the tubular body portion receives the reactants from the conical section, and processes the reactants. An insert may be positioned within the tubular body portion to further process the reactants along the inner surface. A rotating reservoir having a damper can be coupled to the rotating tubular body portion. The damper receives the processed reactants from the inner surface of the tubular body portion, and guides the processed reactants into the rotating reservoir to minimize turbulence. The rotating reservoir then separates the processed reactants by density.

Abstract: Disclosed is a method for developing a filter suitable for specific volatile organic compounds (VOCs) emitted from a brand new vehicle.

Abstract: One exemplary embodiment can be an acid alkylation system. The system can include a cooler-reactor and a settler. The settler can have a height and a width. Usually, the height exceeds the width. Generally, the cooler-reactor receives a feed of at least one of a stream including an olefin and a stream including an isobutane. Typically, at least a portion of one of the streams is bypassed around the cooler-reactor to the settler to control the temperature within the settler.

Abstract: A process and apparatus are disclosed for hydrocracking hydrocarbon feed in a hydrocracking unit and hydrotreating a diesel product from the hydrocracking unit in a hydrotreating unit. The hydrocracking unit and the hydrotreating unit share the same recycle gas compressor. A make-up hydrogen stream may also be compressed in the recycle gas compressor. A warm separator separates recycle gas and hydrocarbons from diesel in the hydrotreating effluent, so fraction of the diesel is relatively simple. The warm separator also keeps the diesel product separate from the more sulfurous diesel in the hydrocracking effluent, and still retains heat needed for fractionation of lighter components from the low sulfur diesel product.

Abstract: A hydrogen separation membrane comprising a palladium alloy that includes at least palladium, an added metal A, and an added metal B, the added metal A and the added metal B being two different metals other than palladium, each of the added metal A and the added metal B forming a complete solid solution with palladium, and the added metal A and the added metal B having a triple point in an equilibrium diagram and not forming an intermetallic compound. The hydrogen separation membrane exhibits excellent hydrogen permeability and durability.

Abstract: This disclosure relates to graphene derivatives, as well as related devices including graphene derivatives and methods of using graphene derivatives.

Abstract: Systems and methods for thermally decomposing hydrocarbon feedstock may comprise a hydrocarbon feedstock, a non-oxidizing carrier gas, one or more heat exchangers, and a reaction chamber. The carrier gas may be used to transfer heat to the hydrocarbon feedstock. The heat exchanger(s) may be configured to heat the carrier gas. And the reaction chamber may be configured to receive hydrocarbon feedstock and heated carrier gas. Inside the reaction chamber, the hydrocarbon feedstock and the heated carrier gas may mix with one another causing the thermal decomposition reaction. The thermal decomposition reaction occurs in a substantially oxidant-free environment thereby eliminating or greatly reducing the production of carbon oxide byproducts. Hydrogen gas may be separated from a gaseous product stream that is thereafter collected from the reaction chamber. A portion of the gaseous product stream may be thermally coupled to the carrier gas and may thereafter be recycled through the system.

Abstract: The various embodiments relate to a system and method for regenerating a direct oxidation catalyst that coverts H2S to elemental S. One embodiment of the method comprises regenerating a direct oxidation catalyst by contacting the direct oxidation catalyst with steam.

Abstract: A compact treatment apparatus and methodology is provided for scavenging at least H2S from an acid gas stream. The vessel is charged with a batch of an aqueous solution of H2S scavenging treatment liquid. Acid gas is discharged from a sparge bar fit with graduated openings, either graduated from small to large or from a few to many and spaced therealong, for distributed discharge into the treatment liquid. The acid gas percolates up through the liquid and into a vessel headspace, the gas being scrubbed of H2S for producing a treated discharge gas. The treatment solution can be an aqueous solution of incorporating one of several active H2S scavenger ingredients including amine-aldehyde compositions or triazines.

Abstract: A hydrogen generator including an initiator assembly having one or more contact members within a compressible member, and a removable fuel unit adjacent a surface of the compressible member. The fuel unit contains a hydrogen containing material that can release hydrogen gas when heated and an exothermic mixture that can react exothermically upon initiation by the initiator assembly. When no fuel unit is in the hydrogen generator, the compressible member is uncompressed and the contact members are at or below its surface, and when a fuel unit is disposed in the hydrogen generator, the compressible member is compressed so the contact members extend beyond the surface to make thermal contact with the fuel unit. Energy from the initiator assembly is conducted by the contact members to corresponding quantities of the exothermic mixture to initiate an exothermic reaction, providing heat for the release of hydrogen gas from the hydrogen containing material.

Abstract: A hydrocarbon-containing mixture including acetylene and butenyne is disclosed. The hydrocarbon-containing mixture can include 10% to 89% acetylene, 10% to 89% butenyne, and at least 0.25% dimethyl butadiyne. A method and system for producing the hydrocarbon-containing mixture is also disclosed. The system can include an acetylene production subsystem comprising at least one vessel and an acetylene output for delivering acetylene to a finishing vessel via a finishing vessel inlet. The finishing vessel can include a diffuser in fluid communication with the finishing vessel inlet, and gas exiting the diffuser can pass through a reaction chamber filled with solid calcium carbide before passing through a finishing vessel outlet.

Abstract: The present invention discloses a reduction-oxidation furnace for thermally refining phosphorus. The reduction-oxidation furnace comprises a furnace body and a blow gun, wherein the furnace body has a slag outlet, a fume outlet, and a melt inlet for feeding melts formed by melting rock phosphate into the furnace body and wherein the blow gun has an end inserted into the furnace body. The content of impurities in fumes containing phosphorus pentaoxide is low, the phosphorus pentaoxide can be easily extracted with a high purity of the phosphorus pentaoxide and at low cost by means of the reduction-oxidation furnace for thermally refining phosphorus according to the present invention.

Abstract: Various systems, devices, NO2 absorbents, NO2 scavengers and NO2 recuperator for generating nitric oxide are disclosed herein. According to one embodiment, an apparatus for converting nitrogen dioxide to nitric oxide can include a receptacle including an inlet, an outlet, a surface-active material coated with an aqueous solution of ascorbic acid and an absorbent wherein the inlet is configured to receive a gas flow and fluidly communicate the gas flow to the outlet through the surface-active material and the absorbent such that nitrogen dioxide in the gas flow is converted to nitric oxide.

Abstract: Ammonia oxidizers are disclosed that can include gas distributors and distribution rings to improve the distribution of the flow of a gas feedstream across a catalyst bed in the ammonia oxidizer. The gas distributors include circular plates that have holes through which the gas feedstream is distributed across the catalyst bed. In some examples, the gas distributors also have a sidewall. The distribution rings are attached to the inner wall of the ammonia oxidizer at a predetermined distance below the gas distributor.

Abstract: A process for treating spent pickle liquor has the steps of mixing the spent pickle liquor with sulfuric acid, introducing oxygen into the mixture of spent pickle liquor and the sulfuric acid for a period of time, and producing diiron(II) tetrachlorosulfate from the oxygen-introduced mixture of sulfuric acid and spent pickle liquor. The spent pickle liquor and the sulfuric acid are introduced into a column. The oxygen is passed under pressure into the column. The intimate mixture of spent pickle liquor, sulfuric acid and oxygen are maintained under pressure for a period of time.

Abstract: A system for producing enhanced wax alternatives, including a high shear device comprising a rotor and a stator, and configured to process petroleum wax and base oil with a hydrogen-containing gas under shearing conditions to form a feedstock, wherein at least one of the rotor and the stator comprises a toothed surface; and a reactor comprising a reactor inlet and a reactor outlet, and configured for hydrogenation of the feedstock for a time sufficient to produce enhanced hydrogenated products, wherein the high shear device is in fluid communication with the reactor, whereby the feedstock is transferable therebetween.

Abstract: A microfluidic system comprising a plurality of photochemical reaction stages, the microfluidic system comprising a computational processor, a plurality of electrically-controllable photochemical reaction stages, and a series of controllable interconnections for connecting the photochemical reaction stages. In an implementation, the computational processor controls the plurality of electrically-controllable photochemical reaction stages and the controllable interconnections so as to implement a multi-step photochemical synthesis function.

Abstract: A polyolefin production system including: a first reactor configured to produce a first discharge slurry having a first polyolefin; a second reactor configured to produce a second discharge slurry having a second polyolefin; and a post-reactor treatment zone having at least a separation vessel configured to receive the second discharge slurry or both the first discharge slurry and the second discharge slurry.

Abstract: A fuel cartridge and a hydrogen generator are provided for supplying hydrogen gas to a hydrogen gas device. The fuel cartridge includes a fuel composition disposed in a container and a multi-layer package material, such as a laminate, enclosing the fuel composition therein. The laminate includes a polymer layer distal the fuel composition and a conductor layer proximate the fuel composition and including a preformed portion. The hydrogen generator includes a punch thermally coupled to a heater assembly and is configured to move between a retracted state and a puncture state. When the fuel cartridge is disposed in the hydrogen generating apparatus, the punch is configured to puncture the polymer layer and bring the coined portion into contact with the fuel composition. Heat is applied to a hydrogen containing material in the fuel composition through the punch and preformed portion to release hydrogen gas.