Described herein is a method for operating a refrigerated shipping container containing respiring produce, the method including: passing a cooled CO.sub.2-rich air stream from an internal environment within the shipping container through a CO.sub.2 selective membrane of a membrane system to produce a cooled CO.sub.2-lean air stream and a CO.sub.2-rich permeate stream; retaining or returning the cooled CO.sub.2-lean air stream to the internal environment; and exhausting the CO.sub.2-rich permeate stream to an external environment outside of the shipping container; drawing external air or permitting external air to pass into the shipping container through an air vent with a pre-set fixed opening of the shipping container in a volume to at least balance a volume difference between the cooled CO.sub.2-rich air stream and the cooled CO.sub.2-lean air stream; wherein the membrane system is operated according to a pre-set mode, and the pre-set mode is independent of a measured gas concentration or pressure of the internal environment; and the pre-set fixed opening of the vent is selected based on one or more characteristics of the respiring produce and the pre-set mode of the membrane system.

A roof vent system for a grain storage device is disclosed. A roof vent including a lid is operatively connected to the roof panel adjacent the opening. The lid is configured to move between an open position and a closed position. A bias member configured to apply an upward bias force to the lid to automatically move the lid to the open position. A control lever that is movable between an upper position and a lower position. The control lever is operably connected to the lid by a pull. When control lever is moved to the lower position with a force greater than the bias force of the bias member, the lid is moved to the closed position. A sealing member attached to the lid is configured to provide a seal between the lid and the roof panel when the lid is moved to the closed position.

A method of preparing non-volatile bituminous material in solid form includes first accessing molds having mold cavities defining an irregularly shaped brick having a plurality of non-planar surfaces and preparing the bituminous material for casting by heating it until it is suitably viscous for casting and optionally blending it with an additive. Then, the molds can be filled with the bituminous materials, preferably using a retractable conduit that progressively fills each mold cavity from its bottom to its top. Next, the bituminous material in the molds is solidified until substantially solid bricks are formed. Optionally, a skeleton with optional additional buoyant features can be placed in each mold cavity prior to casting so that the resulting brick has increased buoyancy throughout, and the skeleton and any buoyant features can be customized according to the needs of the customer. The resulting bricks can be removed for transport.

A filter pad with a dry loft between approximately 0.15 and 0.5 inches includes at least a first fiber web comprising a plurality of oleophilic fibers, wherein the oleophilic fibers: have a linear density between approximately 2 and 9 denier; have a length between approximately 1 and 4 inches; and have been uploaded with flame resistant particles.

A method of transporting non-volatile bituminous materials from a first location to a second location involves carrying a plurality of irregular bricks formed by the bituminous material in transport chambers carried by vehicles. Bricks are defined by a plurality of non-planar surface, which create gaps between adjacent bricks, and can further include polymer skeletons and other features that help them float. The bricks can travel by land, sea, air, or rail and need not be heated while in transit. Transport chambers have active or preferably passive environmental control systems to circulate cooling air, water, or other substances through the transport chamber and the gaps between adjacent bricks. In a preferred embodiment, ambient air circulates among the bricks during travel by land and ambient water circulates among the bricks during marine travel. The vehicles carrying the transport chambers can be low-emissions or zero-emission vehicles including fuel-cell powered trains and ships.

A substantially solid brick of non-volatile bituminous material has a shape that is defined by an irregular outer surface to minimize surface contact with nearby bricks when shipped in bulk. The overall shape is preferably that of a modified tetrahedron having three non-planar face surfaces, a top surface, and a surface or point. Both the top and bottom surfaces are preferably modified domed shapes comprised of several sections. The face sections are preferably modified concave surfaces comprised of several triangular sections that can be planar, concave, or convex. Curved edges connect the face sections to each other and can include several planar edge sections. The bituminous material can include additives, and the brick can further include a skeleton distributed throughout. The skeleton can be a customizable matrix, framework of fiber groups, or other structure and can include customizable buoyant features such as air pockets or capsules.

A method of preparing non-volatile bituminous material in solid form includes first accessing molds having mold cavities defining an irregularly shaped brick having a plurality of non-planar surfaces and preparing the bituminous material for casting by heating it until it is suitably viscous for casting and optionally blending it with an additive. Then, the molds can be filled with the bituminous materials, preferably using a retractable conduit that progressively fills each mold cavity from its bottom to its top. Next, the bituminous material in the molds is solidified until substantially solid bricks are formed. Optionally, a skeleton with optional additional buoyant features can be placed in each mold cavity prior to casting so that the resulting brick has increased buoyancy throughout, and the skeleton and any buoyant features can be customized according to the needs of the customer. The resulting bricks can be removed for transport.

A receiver for irregularly shaped bricks cast from non-volatile bituminous material includes a receiver with a specialized storage chamber that can receive viscous bituminous material and a concave lid preferably modified with a radiant heating system that can accept and melt or soften arriving bricks. The lid includes multiple openings or other delivery routes that funnel the melted bituminous material to the chamber below. The radiant heating system can be electrical where cables or grids are embedded in the lid or where conductive materials coat or are distributed throughout the lid. Alternatively, the radiant heating system can be hydronic where channels or conduits are embedded in the lid to circulate heated liquid such as water or water mixed with propylene glycol. The receiver can also include blenders, skimmers, and additional heaters to further skim, blend, or process the bituminous material collected in the chamber.

A hopper bottom a grain bin above a foundation includes a conical wall tapering inwardly to a bottom discharge opening. An outer cylindrical wall is joined to the top peripheral edge of the conical wall. Upright support legs are connected to the outer wall for supporting the cylindrical grain bin walls thereabove. A bottom wall is connected radially between the outer wall and the conical wall so as to define a manifold passage bounded by the conical wall, the outer wall and the bottom wall which is generally annular in shape and which is located externally of the conical wall. Vent openings are formed in the conical wall to receive aeration air from a blower connected to the manifold passage. A cover member is supported above the vent openings in the conical wall in connection with the outer wall above the conical wall to prevent material entering the vent openings.

Described herein is a method for operating a refrigerated stripping container containing respiring produce, the method including: passing a cooled CO.sub.2-rich air stream from an internal environment within the shipping container through a CO.sub.2 selective membrane of a membrane system to produce a cooled CO.sub.2-lean air stream and a CO.sub.2-rich permeate stream; retaining or returning the cooled CO.sub.2-lean air stream to the internal environment; and exhausting the CO.sub.2-rich permeate stream to an external environment outside of the shipping container: drawing external air or permitting external air to pass into the shipping container through an air vent with a pre-set fixed opening of the shipping container in a volume to at least balance a volume difference between the cooled CO.sub.2-rich air stream and the cooled CO.sub.2-lean air stream; wherein the membrane system is operated according to a pre-set mode, and the pre-set mode is independent of a measured gas concentration or pressure of the internal environment; and the pre-set fixed opening of the vent is selected based on one or more characteristics of the respiring produce and the pre-set mode of the membrane system.