Abstract: Disclosed herein are roll fed air heated flotation ovens and related thermoforming systems, assemblies, and machines that enable the corrugation-free expansion of a gas impregnated thermoplastic web passing through an oven chamber (without use of a pin-chain assembly), as well as to related methods. In an embodiment, a gas impregnated thermoplastic web is conveyed and expanded through an elongated air heated oven chamber, wherein the elongated oven chamber includes a plurality of downwardly directed heated air nozzles positioned at regular intervals along and within the upper portion of the oven chamber, and a plurality of upwardly directed heated air nozzles positioned at regular intervals along and within the lower portion of the oven chamber, but staggered apart from the downwardly directed heated air nozzles such that the gas impregnated thermoplastic material web undulates in an up and down wavelike fashion, thereby minimizing sagging, bagging, puckering, and/or buckling of the web.

Abstract: A continuous process for making a flexible porous dissolvable solid structure with open celled foam. The continuous process has the steps of preparing a pre-mixture comprising surfactant, polymer, water, and optionally plasticizer; aerating the pre-mixture to form a wet aerated pre-mixture; extruding the wet aerated pre-mixture to form one or more sheets on a belt; and drying the sheets to form an Article having an open celled foam.

Abstract: Technologies are provided herein for fabricating foamed structures using a three dimensional fabricator. In particular, the present disclosure provides systems and methods of producing foamed structures using foamed materials, lattice foamed materials, and/or layer deposition employing the concept of viscous thread instability.

Abstract: A method of forming a blown polymeric foam film is described herein. As described further below, equipment design (e.g., die design) and processing conditions may be controlled to form blown films having desired characteristics.

Abstract: An apparatus and process for making a foam having a controlled size distribution of gas bubbles in a liquid matrix. The invention utilizes a porous material having a controlled pore size and pore distance to produce a substantially uniform size distribution of gas bubbles; a gas pumping device for directing a flow of gas to and through the porous material to form the gas bubbles; a fluid pumping device for directing a flow of liquid matrix past the porous material and a rotating element moving in the vicinity of the membrane surface causing an additional flow to detach, collect accumulate and entrain the gas bubbles in the liquid matrix to form a foam having gas bubbles of generally uniform size and a substantially uniform gas bubble size distribution.

Abstract: A process for producing cellular thermoplastic articles. The process comprises the steps of treating a solid parison made from a thermoplastic material with a saturating gas at an elevated pressure for a period of time to provide a gas-saturated parison; heating the gas-saturated parison to prepare a cellular parison; placing the cellular parison in a mold; and blowing a molding gas into the cellular parison to expand the cellular parison into the shape of the mold to provide a shaped cellular article.

Abstract: An extruded polypropylene type resin foam having a high expansion ratio of at least 15 times and a closed cell ratio of at least 70% and excellent in the heat insulation property, and its production process, are provided. An extruded polypropylene type resin foam, which is produced by extrusion-foaming a polypropylene type resin composition containing a linear polypropylene type resin having a melt tension at 230° C. of from 5 to 30 g, by using a blowing agent containing at least a hydrocarbon type gas, and which has an expansion ratio of at least 15 times and a closed cell ratio of at least 70%.

Abstract: Process for the production of moldings from nanoporous polymer materials, comprising the stages of a) preparation of a multiphase polymer mixture with domains in the range from 5 to 200 nm, b) impregnation of the polymer mixture with a blowing agent, where the solubility of the blowing agent in the phase forming the domains is at least twice as high as in the adjacent phases, c) expansion of the multiphase polymer mixture comprising blowing agent, by introducing the polymer mixture into a cavity and expanding it therein, thus obtaining the molding.

Abstract: The present invention relates to a microporous polyethylene film for use as battery separator. The microporous polyethylene film according to the present invention is characterized by having a film thickness of 5-40 ?m, a porosity of 35-55%, a permeability from 2.5×10?5 to 10.0 10?5 Darcy, a puncture strength of at least 0.10 N/?m at 90° C., a puncture angle of at least 30° at 90° C., and a permeability from 2.0 10?5 to 8.0 10?5 Darcy after shrinking freely at 120° C. for 1 hour. The microporous polyethylene film in accordance with the present invention has very superior puncture strength and thermal stability at high temperature and takes place of less decrease of permeability due to low thermal shrinkage at high temperature, as well as superior permeability. Therefore, it can be usefully applied in a high-capacity, high-power battery to improve thermal stability and long-term stability of the battery.

Abstract: The present invention provides an injection molding method capable of impregnating a supercritical fluid stably and partially in molten resin in a plasticizing cylinder of an injection molding apparatus. The above object is achieved by providing the method of injection molding which includes measuring a filling amount of the molten resin in the plasticizing cylinder, introducing a supercritical fluid into the molten resin in the plasticizing cylinder while moving back the screw by a predetermined distance without rotating the screw from a position of the screw at the time of completing the measuring, detecting a pressure of the molten resin, and determining based on the pressure an injection start position for the screw.

Abstract: Injection molding systems and methods useful for making microcellular foamed materials are provided as well as microcellular articles. Pressure drop rate and shear rate are important features in some embodiments, and the invention provides systems for controlling these parameters in an injection molding system. Another aspect involves an injection molding system including a nucleator that is upstream of a pressurized mold. Another aspect involves an extrusion system with the reciprocating screw for forming a single phase solution of non-nucleated blowing agent and polymeric material. Another aspect involves very thin walled microcellular material and very thin walled polymeric material. Another aspect provides a method for producing high weight reductions in very thin-walled parts with surfaces that have no noticeable differences from non-foamed parts.

Abstract: A blowing pad, a fabrication method of the blowing pad, and a blowing system using the blowing pad are provided. The blowing pad includes a main foam formed of a foamed porous synthetic resin, and a duct embedded in the main foam, wherein the main foam includes an air inlet to which an air inlet tube is inserted and a plurality of vent holes, each of which is connected to the duct, wherein the duct is formed of any one of natural rubber, synthetic rubber, and non-porous plastic, wherein the air inlet tube is connected to an external blowing pipe.

Abstract: Disclosed herein are methods and pressure vessels for solid-state microcellular processing of thermoplastic rolls and sheets. In one embodiment, the present invention is directed to a method for making a gas impregnated interleaved roll, which method comprises: providing a pressure vessel having an internal pressure chamber and a rotatable shaft horizontally positioned within the pressure chamber; placing an interleaved roll about the rotatable shaft and within the pressure chamber, wherein the interleaved roll is made from a thermoplastic material sheet interleaved together with a gas-channeling material sheet; pressurizing the pressure chamber to a selected pressure; rotating the rotatable shaft having the interleaved roll thereabouts (thereby rotating the interleaved roll) while under pressure for a selected period of time; and depressurizing the internal chamber to yield the gas impregnated interleaved roll.

Abstract: Preparations with enlarged surface comprising an active ingredient and an amphiphilc copolymer, wherein the copolymer comprises at least one polyether-containing graft polymer. The preparations are partially or completely foamed. Processes for producing the preparations are also described, including processes comprising extrusion of a melt impregnated with a physiologically acceptable volatile blowing agent.

Abstract: A method of fabricating three-dimensional scaffolds includes the steps of forming a plurality of bubbles by providing a gelatin solution and a gas stream passing through a bubble production device, gathering the bubbles, cooling the bubbles, crosslinking the bubbles by adding the agent with aldehyde group, and breaking at least some of the bubbles to be interconnected to form a three-dimensional porous materials.

Abstract: A pre-expanded polypropylene resin particle can be produced in the following manner: a polypropylene resin particle produced by an under water cut method, water, a dispersing agent, and a foaming agent are charged in a pressure-resistant container, the resulting mixture is heated to a temperature equal to or higher than the softening temperature of the polypropylene resin particle to allow the polypropylene resin particle to be impregnated with the foaming agent under pressure, and the resulting product is released into the atmosphere having a pressure lower than the pressure of the inside of the pressure-resistant container. As the polypropylene resin composition, a composition is used which comprises 100 parts by weight of a polypropylene resin and 1 to 20 parts by weight of a polyethylene resin having a melt viscosity of 10 to 2000 mPa·s at 140° C.

Abstract: The invention is directed to an article made from co-injection molding using gas-assist. The article has an inner material and an outer material. The inner material has a blowing agent uniformly distributed throughout the inner material. The outer material surrounds the inner material. The use of the blowing agent in the inner material produces a repeatable and consistent structure, as the blowing agent is uniformly activated through the product. The use of the gas-assist the heat and pressure associated with the blowing agent is allowed to out gas, thereby insuring that the finished molded chair or other item is aesthetically pleasing while providing increased strength and reduced weight compared to traditional plastic chairs formed with known methods.

Abstract: A dual platen molding machine for constructing a plurality of pre-insulated structural panels is disclosed that includes multiple safety features. The molding machine produces one or more panels that may include one or more c-channels or profiles embedded in expandable polystyrene (EPS) foam to provide structural integrity to the panels, and resulting wall. A chase may be formed horizontally in the panels to provide a wiring conduit through the panel. The molding machine is electrically operated to control the movement of a movable molding portion when closed upon a stationary molding portion. Steam may be controlled to fuse insulating material such as expandable polystyrene (EPS) in cavities formed between the movable mold and the stationary mold. No hydraulics is required to operate the dual platen molding machine, thus improving operating and maintenance costs. Moreover, steam hoses may be avoided, thereby improving overall safety.

Abstract: A lightweight cast article that is made by the method of the present invention. A foamed acoustical product is prepared by blending a starch with cold water, then heating the starch/water blend to form a starch gel. Mineral wool is added to the starch gel to form a pulp and the pulp is wet-mixed until wool nodules are formed. The pulp is then combined with a surfactant and an amount of foam water. The foaming agent is selected from the group consisting of a linear sodium dodecylbenzene sulfonate, a cocamidopropyl betaine, a cocamidopropyl hydroxysultaine, their salts and mixtures thereof. Mixing of the foaming agent and pulp continues to form a foamed pulp. The foamed pulp is cast into a mold and allowing the foamed pulp to dry forming a foamed product. The foamed product is removed from the mold.

Abstract: A method for manufacturing a vehicle lighting part in accordance with principles of the presently disclosed subject matter can include using a mold including a fixed section, a movable section, and a core section to slide according to a movement of the movable section, and an injection molding unit. The exemplary method can also include putting a first mixture of the molding compound and a chemical foaming agent into the injection molding unit, the molding compound containing polypropylene series resin to which a predetermined amount of talc is added. The method can also include producing a second mixture by enclosing a physical foaming agent in the first mixture in the injection molding unit. Finally, the exemplary method can include injecting the second mixture from the injection molding unit into the mold to fill the mold, and performing a core back of the core section immediately after injecting the second mixture into the mold to fill the mold.

Abstract: Compositions and methods are disclosed that relate to a biopolymer medium for growing plants. In certain embodiments, the biopolymer growth medium comprises or consists essentially of polylactic acid (PLA), polyhydroxyalkanoate (PHA) or a mixture of them. Another aspect of the invention relates to a method of producing a biopolymer growth medium.

Abstract: The present invention is an apparatus for generating foam shapes that float in air having a container, a gas source, an aeration nozzle for aerating a gas from the gas source, an outlet, and a separator for separating extruded foam into individualized foam shapes.

Abstract: A green tire disposed on a toroidal support is introduced into a vulcanisation mold. The mold is closed through axial approaching of a pair of sidewall plates acting against the sidewalls of the tire. Circumferential sectors set to operate against the tire tread band are maintained spaced apart from the tread band itself during admission of a working fluid designed to press the tire against the toroidal support. Subsequently, the sectors are centripetally approached for penetration into the tread band concurrently with a step of full molding and vulcanisation of the tire carried out through admission of steam under pressure into the tire itself.

Abstract: Structural inorganic cellular materials with controlled open porosity are produced by foaming fine particulate-laden aqueous solutions into stable, uniform, dodecahedral froth structures which are dried and sintered by microwave energy or high voltage instant electrical discharge. Porous open cell biomedical implants such as niobium or tantalum acetabular caps with engineered osteoconductive porosity are among the products achievable.

Abstract: Inflated fibers of regenerated cellulose and other regenerated structures are formed from ionic liquid/cellulose dope. Fibers so produced may be incorporated into absorbent sheet with other papermaking fibers to provide softness, bulk and absorbency.

Abstract: A method for the manufacture of a molding composition from a raw material melt which is charged with an additive includes the steps: charging a conveyor apparatus with a raw material which includes a liquid or gooey pasty composition or a granulate; converting the raw material into a raw material melt by heat supply to the raw material; charging the raw material melt with an additive; mixing of the raw material melt with the additive to produce a molding composition; and discharging the molding composition from the conveyor apparatus. The charging of the raw material melt with the additive takes place through a metering device which is arranged in a passage section of the conveyor apparatus and/or subsequent to the conveyor apparatus with the raw material melt flowing through and/or around the passage section. The metering device includes at least one metering element which is arranged in a recess of the passage section.

Abstract: An embryo replacement catheter has a flexible extruded shaft of a transparent polyurethane with a bore extending along its length. Gas bubbles of a diameter in the range 5? to 10? are incorporated into the thickness of the wall of the shaft by adding gas during extrusion. The bubbles are selected to increase the visibility of the catheter under ultrasound imaging whilst still enabling material flowing along the catheter to be seen.

Abstract: The present invention provides an apparatus for producing a hard polyurethane foam by a froth process in which interlocking of the supply of the inert gas compressed or liquefied as a foaming agent with the operation of a foaming machine is made possible.

Abstract: The present invention is an apparatus for generating foam shapes that float in air having a container, a gas source, an aeration nozzle for aerating a gas from the gas source, an outlet, and a separator for separating extruded foam into individualized foam shapes.

Abstract: The present invention is an apparatus for generating foam shapes that float in air having a container, a gas source, an aeration nozzle for aerating a gas from the gas source, an outlet, and a separator for separating extruded foam into individualized foam shapes.

Abstract: Process for manufacturing a plastic-based cellular structure, in which: parallel lamellae of a composition based on at least one plastic are continuously extruded, in an approximately horizontal direction, through a die having a front face provided with a plurality of parallel slots and with an insulating material, at least on the surface; and upon exiting the die, the spaces lying between two adjacent lamellae are subjected, in successive alternations and between two sizing units whose length is short enough for the plastic composition to remain molten, to an injection of compressed gas and to a vacuum, the two sides of a given lamella being, in respect of one of them, subjected to the action of the compressed gas and, in respect of the other of them, subjected to the action of the vacuum, and vice versa during the next alternation, so as to deform the lamellae and weld them together in pairs, with formation, in a plane approximately parallel to the extrusion direction, of a cellular structure whose constitu

Abstract: A method for making a shapeable article from poly(lactic acid) includes treating solid poly(lactic acid) that results in the solid poly(lactic acid) having a crystallinity of at least 20% by weight based on the weight of the solid poly(lactic acid) and a gas concentration of 6% to 16% by weight based on the weight of the solid poly(lactic acid); and heating the solid poly(lactic acid) having said minimum crystallinity and gas concentration to produce a cellular poly(lactic acid) article that is shapeable. The shapeable cellular poly(lactic acid) article is advantageous in that the article can be further shaped by heat and/or pressure (or vacuum), such as via thermoforming, into a variety of useful products.

Abstract: A process for producing cellular thermoplastic articles. The process comprises the steps of treating a solid parison made from a thermoplastic material with a saturating gas at an elevated pressure for a period of time to provide a gas-saturated parison; heating the gas-saturated parison to prepare a cellular parison; placing the cellular parison in a mold; and blowing a molding gas into the cellular parison to expand the cellular parison into the shape of the mold to provide a shaped cellular article.

Abstract: [Problems] To provide a foamed plastic container in which the cell diameters are varying along a gradient so will not to decrease the content protection performance, quite differently from the foamed cells distributed in the conventional foamed containers. [Means for Solution] The foamed plastic container has a container wall 10 formed by using a plastic material and in which foamed cells 1 are distributed, the lengths of the foamed cells in the surface direction of the container wall 10 decreasing from the outer surface of the container toward the inner surface thereof.

Abstract: An injection-foaming method for a thermoplastic resin comprising using an injection unit 30 provided with a hopper 35, a plasticizing cylinder 31 and a screw 32, and a mold 10 having a mold cavity 10a of changeable capacity; filling the mold cavity 10a with a foaming-agent-containing melted resin injected from the injection unit 30; and then enlarging the mold cavity 10a for allowing the foaming-agent-containing melted resin to expand, wherein inclusion of a foaming agent into a thermoplastic resin is done by using a mixture of a foam nucleating agent and a foaming gas as foaming agent, feeding the mixture to hopper 35 or plasticizing cylinder 31 and screw 32 of injection unit 30 at a pressure of 0.1 MPa or more and less than 1.0 MPa, and contacting the mixture with a pre- or post-plasticized thermoplastic resin present in hopper 35 or plasticizing cylinder 31 and screw 32.

Abstract: A container comprises a micro cellular foamed polymer, and a non-reactive gas contained within the micro cellular foam cells, wherein the container has a non-transparent appearance. The process for making the container comprises injection molding a polymer preform having a non-reactive gas entrapped within the walls thereof, cooling the preform to a temperature below the polymer softening temperature, reheating the preform to a temperature above the polymer softening temperature, and blow molding the preform, to prepare a container comprising a micro cellular foamed polymer having a non-reactive gas contained within the micro cellular foam cells.

Abstract: To provide a foam board of a polyolefin resin which has an excellent heat insulating property and sound absorption property, of which a product can be material-recycled and which can continuously be produced at a low cost. A method for producing a foam board, which comprises extrusion-foaming by ejecting a mixture of a polyolefin resin composition containing a linear polypropylene resin having a melt tension of from 5 to 30 g at 230° C. and a foaming agent containing at least carbon dioxide in the supercritical state, by means of an extruder which has a multi-hole type die having an opening diameter of from 0.1 to 1.0 mm and the number of openings of from 50 to 5,000 at an ejection amount (V) of from 0.05 to 0.45 kg/hr per one opening in the die at a melt-extrusion temperature of from 160 to 250° C., under atmosphere at a proximal resin pressure of from 7 to 20 MPa at the openings of the die.

Abstract: An apparatus for producing a porous body that forms an expandable slurry containing at least inorganic powder, a foaming agent, and a binder into a sheet, causes the expandable slurry sheet to be foamed and baked, and thereby produces the porous body, the apparatus includes: a mixer preparing the expandable slurry by containing inorganic powder, a foaming agent, and a binder; a die-coater that has a discharge opening which discharges the expandable slurry provided from the mixer to an external thereof so as to shape the expandable slurry into a sheet; and a carrier sheet arranged so as to face the discharge opening of the die-coater with a gap interposed therebetween, and feeding the expandable slurry discharged from the discharge opening, wherein a flow path of the expandable slurry from inside the mixer to the discharge opening of the die-coater is hermetically sealed from an outside.

Abstract: The invention provides a foamed body of thermoplastic resin having a high expansion ratio, desired shape and cells of desired diameter, especially fine cells. The foamed body of thermoplastic resin is produced by filling the thermoplastic resin containing a foaming agent into a cavity 31 of a mold 2a and thereafter enlarging the cavity 31 to expand the resin. In this process, the cavity 31 is completely filled with the resin as melted and containing the foaming agent, then held in its shape as filled with the resin and enlarged to an increased final cavity width upon the average temperature filled in the cavity 31 reaching the range from the melting point of the resin to the melting point plus 30° C.

Abstract: An advanced structural foam molding technology for improving the dispersion of the blowing agent in the polymer matrix has been invented. This technological innovation is an improvement on the well-known existing low-pressure structural foam molding technology based on the preplasticating-type (so called piggy-bag) injection-molding machines. By introducing means for continuing the polymer matrix melt flow stream, preferably an additional accumulator and a gear pump, the processing conditions become more consistent to disperse the injected gas more uniformly in the polymer matrix. By using this technology, the structural foams have a smaller cell size, a more uniform cell structure, a larger void fraction (i.e., more material saving), less surface swirl, and less weld line contrast.

Abstract: A composition includes a set hydraulic binder; and a foaming agent and has a porosity ?0.55; a flow resistivity between 10000 and 200000 N.s.m-4; a tortuosity between 1.2 and 3.4; a viscous characteristic length between 10 ?m and 60 ?m; a thermal characteristic length between 60 ?m and 1000 ?m; and a compressive strength of at least 0.30 MPa as measured by modified ASTM C472.

Abstract: The instant invention relates to a method for changing characteristics of a plastic component, wherein a medium is introduced into the plastic component, which encompasses a porosity and wherein the medium forms a homogenous compound with the plastic component by at least partially dissolving the plastic component.

Abstract: To provide a dustproofing material having superior dustproofness and having such superior flexibility as to fit in a further minute clearance typically of 0.10 to 0.20 mm. Disclosed is a foam dustproofing material which is a dustproofing material including a foam having a thickness of 0.1 to 1.0 mm, in which the foam has a micro cell structure with an average cell diameter of 10 to 65 ?m, has such characteristic properties as to give a load against repulsion of from 0.010 to 0.100 MPa upon compression to a thickness of 0.1 mm, and has an apparent density of 0.01 to 0.050 g/cm3. The foam preferably has a closed cell structure or semi-open/semi-closed cell structure. The foam dustproofing material may further include a pressure-sensitive adhesive layer on one or both sides of the foam. The pressure-sensitive adhesive layer is preferably present above the foam through a film layer.

Abstract: A method for combining materials (such as impregnating materials with functional materials) uses a combination of supercritical fluid technology and polymer melt processing technology. The functional material is soluble in a near supercritical or supercritical fluid, which dissolves in the matrix/bulk material during melt processing. Controlling the processing conditions facilitates a change of state for the fluid, which results in the precipitation of the functional material in the bulk material. The impregnated bulk material may be shaped using conventional polymer based processing techniques such as extrusion and injection moulding.

Abstract: A mirror assembly includes a reflective element portion and a molded portion formed of a multi-void, lightweight structure. The multi-void, lightweight structure may be formed by injecting a gas into an injection mold while the molded portion is being molded, resulting in a multi-void aerated molded structure having multiple-voids introduced during the molding step. A window assembly for a vehicle may include an outer frame portion, an inner frame portion hingedly attached to the outer frame portion, and at least one sealing element established along a sealing portion of the outer and/or inner frame portions. The outer frame portion may be pivoted relative to the inner frame portion and about the hinge portions to a closed position. The outer frame portion may be connected to the inner frame portion when in the closed position to secure the at least one sealing element therebetween.

Abstract: The present invention provides a method of producing a polyethylene terephthalate graft copolymerized resin, comprising subjecting the following mixture to a homogeneous reaction at a temperature of 250° C. or higher to impart a high melt viscosity to the mixture, the mixture containing (A) 100 parts by weight of a polyethylene terephthalate polyester as a main material, (B) 0.01 to 2 parts by weight of a polymeric polyfunctional epoxy compound containing 7 to 100 epoxy groups in a molecule and having a molecular weight of 1,000 to 300,000 as a coupling agent, (C) 0.01 to 1 part by weight of a metal salt of an organic acid as a coupling reaction catalyst, and (D) 0 to 100 parts by weight of an aromatic alicyclic polyester and/or an aromatic aliphatic polyester each having a carboxyl group in an aromatic nucleus as an auxiliary material.

Abstract: A gas injecting device for an injection molding machine is equipped at one side of a cylinder of the injection molding machine, and includes a pin inserted into a gas injection hole of the gas injecting device. The pin has flat sections formed around an outer lower portion of the pin to define gaps between the flat sections and an inner surface of the gas injection hole, such that a gas is injected uniformly through the gaps, thereby allowing the gas and a resin to be easily mixed while preventing the resin from flowing backwards through the gas injecting device. An amount of gas injected to a barrel of the injection molding machine is accurately controlled according to a pressure difference between a gas line and the barrel, and time data, allowing an article to be injection molded according to a kind of resin or characteristics of the article.

Abstract: A molded article includes thermoplastic resin, and an organic material different from the thermoplastic resin inside said molded article, the organic material being located on and near a surface of said molded article.

Abstract: The present invention relates to personal care compositions, especially those personal care compositions in the form of a personal care article that is a porous dissolvable solid substrate. The porous dissolvable solid substrate has a surface resident coating comprising an inorganic particulate perfume complex that can provide a consumer benefit.

Abstract: The present invention is directed to a deep draw microcellularly foamed polymeric container comprising a polymeric sidewall integrally connected to a polymeric base along a bottom edge. The polymeric sidewall and base are contiguous with each other and define a shape of an open top container. The polymeric sidewall and base have a contiguous inner microcellular foam structure (having average cell diameters ranging from about 5 to about 100 microns) surrounded by a smooth outer skin layer integrally connected therewith. The polymeric sidewall defines a container height and a top opening, wherein the top opening defines a top opening width, and wherein the polymeric base defines a container base width, and wherein the area defined by the top opening is greater than the area defined by the polymeric base, and wherein the ratio of the container height (h) to the top opening width (w) is greater than about 1:1 (h:w).