Abstract: A wheelchair assembly is provided for easy assembly, disassembly, and transport. The wheelchair assembly includes a plurality of subassemblies, including a first subassembly having a first frame and a second subassembly having a second frame. The wheelchair assembly includes at least one motor and a plurality of wheels. The plurality of subassemblies are configured to be selectively attached with each other to form the wheelchair assembly, and the wheelchair assembly is configured to be easily assembled and disassembled. The subassemblies are configured to be disassembled from each other so that each of the plurality of subassemblies can be separately carried by a single person. The wheelchair assembly is an all-terrain wheelchair assembly.

Abstract: Broad molecular weight polyethylene and polyethylene having a bimodal molecular weight profile can be produced with chromium oxide based catalyst systems employing alkyl silanols. The systems may also contain various organoaluminum compounds. Catalyst activity and molecular weight of the resulting polyethylene may also be tuned using the present invention.

Abstract: A process for producing polymer particles in a gas phase polymerization reaction using a group 4 metal complex containing at least one cyclic ligand containing delocalized ?-electrons and optionally a flow aid.

Abstract: Disclosed herein are various processes, including continuous fluidized-bed gas-phase polymerization processes for making a high strength, high density polyethylene copolymer, comprising (including): contacting monomers that include ethylene and optionally at least one non-ethylene monomer with fluidized catalyst particles in a gas phase in the presence of hydrogen gas at an ethylene partial pressure of 100 psi or more and a polymerization temperature of 105° C. or less to produce a polyethylene copolymer having a density of 0.945 g/cc or more and an ESCR Index of 1.0 or more wherein the catalyst particles are prepared at an activation temperature of 700° C. or less, and include silica, chromium, and titanium.

Abstract: Broad molecular weight polyethylene and polyethylene having a bimodal molecular weight profile can be produced with chromium oxide based catalyst systems employing alkyl silanols. The systems may also contain various organoaluminum compounds. Catalyst activity and molecular weight of the resulting polyethylene may also be tuned using the present invention.

Abstract: Embodiments of our invention relate to processes for transitioning among polymerization catalyst systems including processes for transitioning among olefin polymerization reactions using Ziegler-Natta catalysts systems and chromium-based catalyst systems. Among embodiments contemplated are a method of transitioning from a first catalyst to a second catalyst in an olefin polymerization reactor, comprising: adding to the reactor a deactivating agent (DA) selected from one of carbon monoxide, carbon dioxide, or combinations thereof; adding to the reactor a cocatalyst adsorbing agent (CAA), comprising an inorganic oxide selected from one of silica, alumina or combinations thereof; wherein the first catalyst comprises at least one conventional Ziegler-Natta catalyst, and a cocatalyst, wherein the second catalyst comprises at least one chromium-based catalyst, wherein the reactor is a gas-phase, fluidized bed reactor, and wherein the CAA is substantially free of transition metals.

Abstract: Embodiments of the present invention include a method of polymerizing olefins comprising contacting olefins with a catalyst composition made by the process of combining a hindered polyalicyclic alkyl catalyst precursor with a particulate inorganic oxide for a deposition time greater than 2 hours to form a catalyst composition. Embodiments of the present invention also include catalyst compositions comprising a hindered polyalicyclic alkyl catalyst precursor made by the process of combining the hindered polyalicyclic alkyl catalyst precursor with a particulate inorganic oxide for a deposition time greater than 2 hours to form the catalyst composition.

Abstract: The present invention is directed to the use of aluminum alkyl activators and co-catalysts to improve the performance of chromium-based catalysts. The aluminum alkyls allow for the variable control of polymer molecular weight, control of side branching while possessing desirable productivities, and may be applied to the catalyst directly or separately to the reactor. Adding the alkyl aluminum compound directly to the reactor (in-situ) eliminates induction times.

Abstract: The present invention is directed to the use of aluminum alkyl activators and co-catalysts to improve the performance of chromium-based catalysts. The aluminum alkyls allow for the variable control of polymer molecular weight, control of side branching while possessing desirable productivities, and may be applied to the catalyst directly or separately to the reactor. Adding the alkyl aluminum compound directly to the reactor (in-situ) eliminates induction times.

Abstract: The present invention is directed to the use of aluminum alkyl activators and co-catalysts to improve the performance of chromium-based catalysts. The aluminum alkyls allow for the variable control of polymer molecular weight, control of side branching while possessing desirable productivities, and may be applied to the catalyst directly or separately to the reactor. Adding the alkyl aluminum compound directly to the reactor (in-situ) eliminates induction times.