Abstract: A composite porous structure includes a macroporous open-pore sponge of regenerated cellulose having disposed within the pores a microporous polyvinyl chloride (PVC) substrate. The total empty space of the structure, produced by the pores, is between 60% and 92% of the outer envelope geometrical volume of the structure. The wet compressive strength of the structure is at least ten times greater than the wet compressive strength of the cellulose sponge without the PVC.

Abstract: The present invention is polyurethane dispersion composition that can be mechanically frothed to yield a foam that has good resiliency. Frothed foams of the present invention can be useful in cushioned flooring applications such as attached cushion broadloom, carpet tiles, carpet underlay, or vinyl flooring. Frothed foams of the present invention can also be useful as coatings for various textiles and for diapers.

Abstract: A system for producing blocks of open-cell, flexible polyurethane foam material and for conditioning each freshly-manufactured block to impart thereto optimal flexible foam properties. The system includes means to pour the flowable constituent of the foam material to be manufactured into a production station at the inlet of a conveyor, the constituents interacting to create on the conveyor a block of open-cell flexible foam material which is then wrapped in a plastic film casing that exposes the leading and trailing end of the block so that the encased block is open ended. The conveyor transports the wrapped block toward the rear end of a gate in a conditioning station having a port therein whose front end is coupled by an air duct to a suction fan.

Abstract: The present invention relates to hydrophilic membranes containing blends of polysulfone polymers and sulfonated polymers or copolymers, where the sulfonated polymers or copolymers are sulfonated before blending with the polysulfone polymer. The invention also relates to methods of preparing the hydrophilic membranes. In one aspect of the invention, the membranes are formed by casting a mixed polymer solution comprising a sulfone polymer and a copolymer of a sulfonated polymer and a sulfone polymer and quenching the film in an aqueous bath to produce a coagulated membrane. The membranes can be ultrafiltration or microfiltration membranes, symmetric or asymmetric.

Abstract: There is provided a leukocyte eliminating filter capable of exhibiting an excellent performance of eliminating leukocyte and platelet, which can be obtained through a simple process comprising the steps of coating a substrate constituting the filter with a polymer having a chemical structure represented by any one of the following formulas (I) and (II), and heat-drying the coated polymer: wherein R1, R3, R4, R5R6 and R7 may be the same or different and are individually hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R2 is CONH2 or COOH; R8 is an alkyl group having 1 to 12 carbon atoms; and x is an integer of 3 or 4.

Abstract: In order to provide an open-celled rigid polyurethane foam, which realizes a low material cost per unit volume of the foam and excellent surface smoothness because of its unique structure, and a thermal insulation material comprising the foam, an open-celled rigid polyurethane foam which has an open cell content of not less than 99% in a state that a skin layer is left on the foam is produced by foam molding, preferably multiple-stage compression molding, of foaming components containing a polyol component and an isocyanate component with an equivalent ratio of NCO/OH of about 0.55-0.95, and a blowing agent, preferably water, and a thermal insulation material is produced from the foam preferably subjected to a baking treatment by means of far-infrared ray exposure.

Abstract: A method for continuously producing a rigid polymer foam in rolled form comprising (a) continuously conveying a carrier along a production line, (b) depositing on the carrier a foam-forming mixture, a regulating means being located on the production line to ensure deposition of only enough of the foam-forming mixture for production, after foaming and curing, of a rigid foam having a maximum thickness of less than 1 inch, (c) foaming and curing the deposited foam-forming mixture to produce a rigid foam, and (d) rolling the rigid foam.

Abstract: The present invention relates to produce a polysulfone based hollow fiber membrane, having high water permeable coefficient and excellent permeability with no deterioration of separation capability, characterized by using an internal coagulating liquid and/or an external coagulating liquid containing diethylene glycol(DEG) and/or salt which can form a hydrate in the process of producing the polysulfone based hollow fiber membrane by following steps: (a) Extrude a spinning dope comprising polysulfones resin, organic solvent and polyvinyl pyrrolydone(PVP) into air through a biannular spinning nozzle to obtain an extrudate in the form of a hollow fiber, (b) Simultaneously inject an internal coagulating liquid into the biannular spinning nozzle at inside bore thereof, and (c) Subsequently introduce said extrudate to an external coagulating liquid.

Abstract: An extruded foam product is manufactured with an integral thin coating of a different material on the surface thereof. The coating is applied to the product as part of the extrusion process and prior to foaming and expansion of the product using a co-extrusion die. The coating can have vastly different or specialized properties while having an inexpensive body portion. This co-extrusion arrangement simplifies the manufacturing of the product, and allows a very thin coating to be produced, if desired.

Abstract: Improved asymmetric hyperfiltration membranes and their method of preparation and use are disclosed. The membranes are fashioned from polyimides and conditioned with a lubricating oil. Permselective separation of aromatic hydrocarbons from non-aromatic hydrocarbons in a feed stream may be accomplished using the membranes under hyperfiltration conditions.

Abstract: The present invention is directed to a pre-inked thermoplastic foam which is utilized to form a relief image which includes open cells in the area that is designed to transfer ink and enclosed or sealed cells in the area which is designed to be impermeable to ink or other print medium. The present invention also includes the method of using and manufacturing the pre-inked foam.

Abstract: The invention relates to the use of a neutral or cationic polymer for preventing activation of the contact phase of blood or plasma which comes into contact with a semi-permeable membrane based on polyacrylonitrile bearing fixed negative charges, which is fitted in apparatus for the treatment of blood or plasma by extra-corporal circulation, by combination of the neutral or cationic polymer, before or after formation of the membrane and before its sterilization, so as to modify the electrical properties of the membrane, the Zeta potential “Z” and the electrical resistivity “R” in order to obtain: either an electrokinetic index “I” of less than or equal to 0.8, “I” corresponding to Log10 (|Z|/R), or a positive Zeta potential “Z” of between 0 and 15 mV (limits not included).

Abstract: A plastic foam article 1 produced by extrusion, for example, a plastic foam sheet comprising homopolymers and copolymers of polycyclic olefins, contains at least 10% by volume of open cells 2, 4 which have a polyhedron-like shape and adjoin one another. The deformation-free opening of the cells is brought about by means of an extrusion temperature higher than that for the extrusion of thermoplastic plastic foam articles having a closed-cell structure. This leaves webs 3 of cell walls 5, 6 intact in terms of shape, whether they now have openings 7 or have no through passages, so that the mechanical strength of the cell framework or the three-dimensional matrix is retained.

Abstract: Process for the partial modification of porous, hydrophilitic filter membranes, of filter membranes treated in such manner and filter modules equipped with such filter membranes. When hydrophilic filter membranes are embedded in hydrophobic securing components of filter modules, the membrane filters are hydrophobized beyond the embedding area in an edge region, so that this edge region, that can no longer be wetted by water, forms an air by-pass when the filter modules are tested, rendering thus impossible that the filter modules can be tested. The novel process is intended to modify the edge regions in such a manner that, even after partial areas have been embedded in a hydrophobic polymer material, they remain porous and hydrophilic over the whole of their effective area.

Abstract: In a method of making solvent and acid resistant membrane on the basis of polyacrylnitrile (PAN) and a comonomer copolymerized therewith wherein the membrane is formed from a solution by phase inversion, glycidylmethacrylate is used as the comonomer and the membrane formed thereby is then subjected to ammonia.

Abstract: Methods and compositions are described that provide three-dimensional fibrillar matrices useful as, among other things, structural prosthetics and scaffolds for cells. The porous fibrillar matrices of the present invention have desirable mechanical properties suitable to a variety of applications, including platforms for in vitro cell cultivation, implants for tissue and organ engineering, implants as tendon and facia prosthetics, and product packaging.

Abstract: A polysulfone membrane for purifying blood having excellent compatibility with blood and the process producing the membrane are disclosed. The membrane comprises a mixed polymer phase of a graft copolymer and/or block copolymer having a molecular weight of 3.times.10.sup.5 daltons or more and comprising (A) a hydrophilic segment and (B) a hydrophobic segment (exclusive of polysulfone) in a total amount of from 0.5 to 30 parts by weight per 100 parts by weight of polysulfone, with the monomer unit ratio (A/B) between the segments A and B being from 0.5 to 5. The copolymer is preferably a graft copolymer where the hydrophilic segment is a polyvinylpyrrolidone segment and the hydrophobic segment is a polystyrene segment. The membrane can be prepared by applying a wet film formation process to a dope containing an appropriate solvent of the mixed polymer, such as N,N-dimethylacetamide.

Abstract: A process for producing structural thermoplastic foam is provided which involves gas expansion of a melted thermoplastic resin composition containing an amount of a polyolefin resin effective as a nucleating agent. The thermoplastic resin compositions provided exhibit an improved uniformity of cell structure in the resultant structural thermoplastic foam as a result of the incorporation of the polyolefin nucleating agent. The process and compositions are useful in the production of structural thermoplastic foam articles.

Abstract: Briefly, in one aspect, the present invention provides puncture resistant microporous materials made of melt-processable semi-crystalline thermoplastic polymers. The microporous materials can be produced at relatively high rates and at low cost. Films and multilayer constructions made of the microporous materials and methods of making microporous materials also are provided.

Abstract: A process for rendering hydrophilic a separation membrane having a hydrophobic matrix polymer comprises doping the membrane solvent system with a cyclic ester additive which is compatible with the matrix polymer and adding a wetting agnet additive, such that the resulting membrane is instantaneously wetted. The invention further relates to the membrne formed in accord with this process.

Abstract: A porous ceramic body having a ceramic framework is produced having a surface roughness of about 40 microns or less. The ceramic body has a plurality of pores where each pore is interconnected with at least one adjacent pore. The ceramic body is made from a powdered ceramic component and a pore-forming polymeric component such as polymeric beads. The ceramic component is alumina which can contain at least one other component selected from the group consisting of calcium oxide, silicon oxide, magnesium oxide, barium oxide, titanium dioxide, and zirconium dioxide. The pore-forming polymeric beads, such as polymethylmethacrylate beads, each having a particle size of 100 microns or less, are mixed with the ceramic powder. The powdered mixture is compressed under pressure and heated to form a porous ceramic body. A coating of an aqueous dispersion of a metal oxide can be applied to the surface of the ceramic body and heated to produce a smooth and durable coating.

Abstract: By employing a unique manufacturing process, unique manufacturing equipment, or a unique combination of materials, a fully integrated, multilayer foamed thermoplastic or elastomeric member or profile having a core member peripherally surrounded by an outer protective layer is attained which is virtually incapable of being removed from said core member. By effectively melting the adjacent surfaces of the foamed layers being interengaged, a core member having any desired cross-sectional shape is produced and is peripherally surrounded with an outer layer integrally bonded thereto. In one aspect of the present invention, metallocene catalyzed plastic material is employed in forming the core member to impart desirable physical attributes thereto.

Abstract: The present invention relates to cationically charge-modified membranes and methods of preparing such membranes. In one major aspect of the invention, the membranes are hydrophobic membranes that are treated with one or more polymeric wetting agents to render the membranes substantially hydrophilic, followed by treatment with one or more charge-modifying agents, the agents causing the membranes to possess a fixed formal positive charge. In another major aspect of the invention, a cationic membrane is formed from casting in a film a mixed polymer solution comprising a sulfone polymer and a copolymer of vinylpyrrolidone and a cationic imidazolinium compound, and quenching the film in an aqueous bath to produce a coagulated membrane. The membrane can be further cationically charge-modified with one or more charge-modifying agents.

Abstract: A reinforcing plate is overlaid with a decoration sheet with a first adhesive layer interposed, and heated and pressed to form first laminate. A surface of the decoration sheet in the first laminate is coated with a clear second adhesive layer of a liquid polyurethane resin, a surface of which in turn is overlaid with a clear film and heated and pressed to prepare a second laminate. The second laminate is placed within a mold and a resin is insert molded on the reinforcing plate in the second laminate. A clear hard coating is preferably formed on a surface of the second laminate in order to provide higher abrasion resistance.

Abstract: A molding process in which a material with an open cell, porous structure 10 is placed, aligned or supported inside a suitable enclosed holding device. Another molding material 20 is subsequently injected into the said holding device while gas and/or pressure is sequentially applied to the said holding device, causing a synergistic interaction and joining between the said materials to take place. During the processing phase, gas is evenly dispersed throughout the porous core, effectively equalizing cavity pressure and permitting an even flow pattern to exist, encapsulating or sandwiching the said porous structure, thus forming a composite material with physical properties which are substantially greater than the individual components.

Abstract: A crystalline polymer resin, such as poly(ethylene terephthalate), is heated to melting. One or more blowing agents is selected wherein at least one of the blowing agents has a boiling point greater than the glass transition temperature for the resin and less than the forming temperature, such as the temperature of the mold used to form the useful article. The blowing agent(s) and resin are combined to create a mixture with a blowing agent concentration sufficient to produce a theoretical sheet foam density of less than 0.4 g/cm.sup.3. The mixture is cooled to a temperature approaching the freezing point of the mixture, and then extruded into a substantially uniform closed cell polymer foam sheet of density less than 0.4 g/cm.sup.3. The extruded sheet is then cooled by direct contact with a cooling surface at a surface temperature below the glass transition temperature such that the blowing agent(s) condenses and the sheet has a density of greater than 0.4 g/cm.sup.

Abstract: Polypropylene (PP) membranes having a hydrophilic surface have been prepared by extracting a fugitive hydrophilic pore-forming agent from a gelled film prepared by evaporating the solvent from a homogeneous solution of isotactic polypropylene, functionalized polypropylene and the fugitive agent in a solvent, such as xylene. Most of the functional groups, such as --OH, --NH.sub.2 and --COOH, in the functionalized polypropylene are located on the surfaces of the membrane, including pore surfaces. The resulting membranes, especially membranes having an asymmetric structure, are useful for ultrafiltration, dialysis and/or microfiltration.

Abstract: A foamed rubber composition for pneumatic tires comprises at least one diene polymer as a rubber ingredient and includes closed cells in a matrix rubber, each of these cells being covered with a coat layer made from a given amount of a resin or resin composite having a JIS-C hardness of not less than 75, a particle size of 10-200 .mu.m and a reacted conjugate diene unit content of not less than 10% by weight. In the production of the foamed rubber composition, the melting point or glass transition point of the resin or resin composite is restricted to at least 5.degree. C. lower than the vulcanizing temperature.

Abstract: A cellular material, preferably a low density foam material, having an initial average normal incidence sound absorption coefficient for a selected frequency range is perforated to form a perforated cellular sound absorption material. The perforated cellular sound absorption material formed has an average normal incidence sound absorption coefficient for the selected frequency range greater than the initial average normal incidence sound absorption coefficient of the cellular sound absorption material. The depth(s), diameter(s), shape(s) and pattern of the perforations provide the cellular sound absorption material with the improved sound absorption properties that are reflected in the increased average normal incidence sound absorption coefficient of the material.

Abstract: In order to improve the sealing property and the resistance to pressure of a gasket coated with foam rubber layers, the foam rubber layers are formed on both surfaces of a metal plate from a rubber which is swollen by the medium to be sealed by the gasket, e.g. a rubber having an oil swelling property such as an NBR, is used. In this way the sealing property thereof is improved.

Abstract: The present invention relates to membranes useful in the separation of water from a solution containing volatile organic compounds and water. The membranes may be used in dehydrating an organic/water mixture to purify an organic when an organic is of interest or, alternatively, producing pure water from an organic/water mixture when clean water is of interest. The membranes include a hydrophilic base polymer, an optional pore-forming polymer and a surface modifying macromolecule (SMM) which imparts surface hydrophobicity to the membrane.

Abstract: A process for treatment of zeolite membranes to improve performance which comprises contacting the membrane with a silicic acid or a mixture of silicic acids.

Abstract: A method of making a perforated silicon carbide product in a shorter time and with less labor work to achieve a lower cost and high yield. Openings 13a, 13b are previously formed in a mold 11, and inserts 14 are inserted into the openings to project toward the inside of the mold. A slurry 15 composed of a mixture of a silicon carbide powder, an organic binder and water is put in the mold to conduct a slip casting molding method whereby a molded green product with perforation 16 is obtained.

Abstract: A decorated shaped product having an expression or design applied thereto which closely resembles an actual expression of a source material such as a natural object is disclosed. The product includes a shaped base material formed thereon with a flow pattern and a transfer pattern of which at least a part is subjected to a concealment exposing treatment and which is printed on the shaped base material. Also, a method manufacturing the product and the shaped base material are disclosed.

Abstract: A filtration membrane for micro- or ultra-filtration is formed from a complex of PVDF and calcined .alpha.-alumina (".alpha.-Al") particles, in which complex the particles are reacted and dispersed. The suspended complex is then mixed with a hydrophilic polymer such as polyvinyl alcohol (40%-90% hydrolyzed) referred to herein as HPVA, which reacts with the complex imparting hydrophilicity to the polymer. The novel membrane provides about 50% higher specific flux than a membrane made with the same polymer but without the .alpha.-Al particles. Unexpectedly, the net flux is improved by treating the membrane with a solution of sodium hypochlorite which fails to remove the HPVA from the novel membrane but does remove it from the prior art membrane which does not contain the .alpha.-Al. The preferred membrane comprises a macroporous support coated on its outer surface with a thin tubular asymmetric semipermeable film of polymer containing less than about 50% by is weight of .alpha.-A1 particles.

Abstract: A water wettable permselective membrane for use in hemodialysis, ultrafiltration and microfiltration applications and a device containing the same are provided. The membrane having the above properties comprises a hydrophobic-base polymer, such as a polysulfone or polyethersulfone polymer, and a block copolymer additive wherein one of the blocks of the copolymer additive is a hydrophilic polymer and the other block is a hydrophobic polymer that is analogous in structure to the hydrophobic-base polymer.

Abstract: A separation module to be used for separation and filtration of micro-substances. The separation module comprises a bundled configuration of a plurality of hollow thread-type porous membrane elements made of high polymer material. The bundled configuration is sealingly disposed in a casing, in which the thread-type porous membrane elements are bound each other by means of molten thermoplastic resin.

Abstract: There is an evacuated insulation panel comprising a corestock of an open-cell alkenyl aromatic polymer foam and a deformable receptacle. The foam has an open cell content of about 70 percent or more. The foam is situated within the receptacle. The receptacle is hermetically sealed. The open-cells of the foam and the interior of the receptacle are evacuated to an absolute pressure of about 10 torr or less. The foam has indentations therein which extend in two dimensions across a surface of the foam. The receptacle substantially conforms to the shape of the foam, including the indentations within. The panel has one or more surfaces which are substantially non-wrinkled. Further disclosed is a method for making the panel.

Abstract: The present invention provides a process for making an improved thermally insulated microwave silicate foam susceptor. The process for making the improved microwave susceptor comprises the following steps:a) preparing pourable aqueous alkali metal dielectric sodium silicate slurry,b) pouring said slurry into a smooth surface substrate mold,c) heating said poured slurry at an effective elevated temperature to foam the slurry in said mold;d) drying said foam at an effective elevated temperature to provide said dry silicate foam substrate having a substantially smooth surface;e) coating at least a portion of said substantially smooth surface with an effective amount of a flowable microwave active material coating (MAC) and drying said flowable coating at an effective temperature to form a dry layer of said MAC.

Abstract: This invention provides a composite reverse osmosis membrane having a polyamide type skin layer whose average surface roughness is at least 55 nm, and the polyamide type skin layer comprises the reaction product of a compound having amino groups and polyfunctional acid halide compound having acid halide groups. The composite reverse osmosis membrane of this invention is superior in salt rejection and water permeability. A polymer film is formed on a supporting film by contacting a solution containing e.g., m-phenylenediamine with a porous polysulfone supporting film so as to form a layer of the solution on the supporting film, then contacting the film with a solution of trimesic acid chloride and holding the film in a hot air dryer so that a polymer film is formed on the supporting film. The surface of the polyamide type skin layer can also be treated with quaternary ammonium salt and coated with a crosslinked layer of an organic polymer having positively-charged groups.

Abstract: The present invention relates to a plastic article formed from several foamed thermoplastic elastomers, such as a thermoplastic polyolefin elastomer based on polypropylene and a vulcanized elastomer at least one of an elastomeric styrene/ethylene/butylene/styrene block copolymer, an elastomeric styrene/butadiene/styrene block copolymer, a thermoplastic elastomer based on polypropylene and an elastomeric styrene/ethylene/butylene/styrene block copolymer and a thermoplastic elastomer based on polypropylene and an elastomeric styrene/butadiene/styrene block copolymer. The present invention further provides plastic articles based on a blend of thermoplastic elastomers and thermoplastic elastomer olefins. The invention further provides a process for making these articles.

Abstract: A blocking device for filling a cavity in a hollow structural member includes a foamable material, and magnetic member embedded on a surface of the foamable material, the magnetic member is secured within the hollow structural member and the foamable material is foamed and expanded by the application of heat so that the cavity is filled.

Abstract: A foamed rubber composition for tire comprises a particular amount of particles having specified hardness and average particle size and containing aluminum-bonded hydroxy group and/or silicon-bonded hydroxy group at its surface, and a particular amount of at least one specified silane coupling agent, and develops excellent performances on ice. Further, pneumatic tires contain the foamed rubber composition as a tread rubber.

Abstract: The present invention relates to mat-shaped composites having porosities above 60% and densities below 0.6 g/cm.sup.3, comprising an aerogel and fibers dispersed therein, the aerogel having cracks and the aerogel fragments enclosed by the cracks, whose average volume is 0.001 mm.sup.3 to 1 cm.sup.3, being held together by the fibers. The present invention further relates to processes for producing the composites of the invention and to their use.

Abstract: A foamed rubber composition for pneumatic tires comprises at least one diene polymer as a rubber ingredient and includes closed cells in a matrix rubber, each of these cells being covered with a coat layer made from a given amount of a resin or resin composite having a JIS-C hardness of not less than 75, a particle size of 10-200 .mu.m and a reacted conjugate diene unit content of not less than 10% by weight. In the production of the foamed rubber composition, the melting point or glass transition point of the resin or resin composite is restricted to at least 5.degree. C. lower than the vulcanizing temperature.

Abstract: A polymer bonded sheet product suitable for use as an electrode in a non-aqueous battery system. A porous electrode sheet is impregnated with a solid polymer electrolyte, so as to diffuse into the pores of the electrode. The composite is allowed to cool, and the electrolyte is entrapped in the porous electrode. The sheet products composed have the solid polymer electrolyte composition diffused into the active electrode material by melt-application of the solid polymer electrolyte composition into the porous electrode material sheet. The solid polymer electrolyte is maintained at a temperature that allows for rapid diffusion into the pores of the electrode. The composite electrolyte-electrode sheets are formed on current collectors and can be coated with solid polymer electrolyte prior to battery assembly. The interface between the solid polymer electrolyte composite electrodes and the solid polymer electrolyte coating has low resistance.

Abstract: Plasticizer extraction from polymer membranes such as battery separators and the like, by exposure to a solvent-water combination. The water or steam is supplied to form an additional interface in a bulk solvent, and to agitate the solvent and control the temperature, as well. At the extractor exit, as well as the inlet, a water elbow is furnished in such a manner as to prevent solvent vapor contact with the atmosphere, and to keep the extractor body under some excessive pressure.

Abstract: Apparatus can prewet at least one filter with a supply of liquid and a supply of wetting agent. The apparatus has a container for holding at least the one filter. The apparatus also has a flow arrangement including a circulating subsystem and flushing subsystem. The circulating subsystem is connected to the container and the supply of wetting agent for: (a) circulating the wetting agent through the container during an initial phase, and (b) draining the wetting agent during a subsequent phase back to the supply of liquid. The flushing subsystem is connected to the container and is adapted to be coupled to the supply of liquid for flushing the liquid through the container. After loading a filter into the container, wetting agent is circulated through the container in the initial phase. Then the wetting agent is drained back to the supply of liquid in the subsequent phase. The liquid is flushed through the container without reopening the container, before removing the filter from the container.

Abstract: The flux of a composite reverse osmosis or nanofiltration membrane having a polyamide discriminating layer is enhanced in a one-step process in which the discriminating layer is treated with ammonia or certain alkylamines. It is possible to control both rejection rate and flux of the membrane as well as convert reverse osmosis membranes into nanofiltration membranes.

Abstract: A horizontal vacuum extrusion line includes a fixed bulkhead, a die inside the bulkhead, a telescoping vacuum chamber section and a fixed chamber section. A dam in the fixed section forms a pond for immersion cooling of the extrudate. A truss extends from the dam to the bulkhead supporting, shaping and calibration equipment and extends through the telescoping section. Fluid pressurizable seals at each end of the telescoping section are operable after the telescoping section is closed against the bulkhead and the telescoping and fixed sections are locked together. The telescoping section provide a more compact line and easier access to the complex equipment downstream of the die. The extrudate from the die passes down into the pond and then through an orifice in a hood projecting from the chamber into a lower level portion of the pond exposed to atmosphere. The hood also includes a tractor drive to push the extrudate through the underwater orifice.