Abstract: Use of a metallocene compound of general formula Ind2R?MQ2 as a component of a catalyst system in producing polyethylene, wherein each Ind is the same or different and is indenyl or substituted indenyl; R? is a bridge which comprises a C1 to C4 alkylene radical, a dialkyl germanium or silicon or siloxane, alkyl phosphine or amine, which bridge is substituted or unsubstituted, M is a Group IV metal or vanadium and each Q is hydrocarbyl having 1 to 20 carbon atoms or halogen; and the ratio of meso to racemic forms of the metallocene in the catalyst system is at least 1:3. The metallocene may be supported. The ethylene may be polymerized in a reaction medium that is substantially free of any external comonomer, with comonomer being formed in situ. The produced polyethylene may have long chain branching. The produced polyethylene may be atactic.

Abstract: Use of a metallocene compound of general formula (IndH4)2R?MQ2 as a component of a catalyst system in producing polyethylene, wherein each Ind is the same or different and is indenyl or substituted indenyl; R? is a bridge which comprises a C1 to C4 alkylene radical, a dialkyl germanium or silicon or siloxane, alkyl phosphine or amine, which bridge is substituted or unsubstituted, M is a Group IV metal or vanadium and each Q is hydrocarbyl having 1 to 20 carbon atoms or halogen; and the ratio of meso to racemic forms of the metallocene in the catalyst system is at least 1:3. The metallocene may be supported. The ethylene may be polymerized in a reaction medium that is substantially free of any external comonomer, with comonomer being formed in situ. The produced polyethylene may have long chain branching. The produced polyethylene may be atactic.

Abstract: The present invention discloses a process for preparing a supported catalyst system for the production of polymers by polymerising or copolymerising one or more olefins comprising 2 to 10 carbon atoms, vinyl aromatic compounds or vinyl acetate, which process comprises the steps of providing a mesoporous support of controlled morphology and of depositing a catalyst component on the support. It further discloses the catalyst system obtained by said process and the use thereof for preparing polymers of controlled morphology.

Abstract: Use of a catalyst system comprising a metallocene catalyst component of general formula R″ (CpRn)(Cp′R′n)MQ2 supported on an inert support in the slurry phase production of linear low density polyolefin, wherein Cp is a cyclopentadienyl moiety, Cp′ is a substituted or unsubstituted fluorenyl ring: R″ is a structural bridge imparting stereorigidity to the component; each R is independently hydrogen or hydrocarbyl having 1 to 20 carbon atoms in which 0≦m≦4; each R′ is independently hydrocarbyl having 1 to 20 carbon atoms in which 0≦n≦8; M is a Group IVB transition metal or vanadium; and each Q is hydrocarbyl having 1 to 20 carbon atoms or halogen; the metallocene having a centroid-M-centroid angle in the range 105° to 125°.

Abstract: Use of a catalyst system comprising a metallocene catalyst component of general formula R″(CpRm) (Cp′R′n)MQ2 supported on an inert support in the slurry phase production of linear low density polyolefin, wherein Cp is a cyclopentadienyl moiety, Cp′ is a substituted or unsubstituted fluorenyl ring; R″ is a structural bridge imparting stereorigidity to the component; each R is independently hydrogen or hydrocarbyl having 1 to 20 carbon atoms in which 0≦m≦4; each R′ is independently hydrocarbyl having 1 to 20 carbon atoms in which 0≦n≦B; M is a Group IVB transition metal or vanadium; and each Q is hydrocarbyl having 1 to 20 carbon atoms or halogen; the metallocene having a centroid-M-centroid angle in the range 105° to 125°.

Abstract: Use of a metallocene compound of general formula Ind2R″MQ2 as a component of a catalyst system for the production of a polyethylene copolymer substantially in the absence of comonomer, wherein each Ind is the same or different and is indenyl or substituted indenyl; R″ is a bridge which comprises a C1 to C4 alkylene radical, a dialkyl germanium or silicon or siloxane, alkyl phosphine or amine, which bridge is substituted or unsubstituted, M is a Group IV metal or vanadium and each Q is hydrocarbyl having 1 to 20 carbon atoms or halogen; and the ratio of meso to racemic forms of the metallocene in the catalyst system is at least 1:3.

Abstract: Use of a catalyst system comprising a metallocene catalyst component of general formula R″ (CpRm) (Cp′R′n) MQ2 supported on an inert support in the slurry phase production of linear low density polyolefin, wherein Cp is a cyclopentadienyl moiety, Cp′ is a substituted or unsubstituted fluorenyl ring; R″ is a structural bridge imparting stereorigidity to the component; each R is independently hydrogen or hydrocarbyl having 1 to 20 carbon atoms in which O≦m≦4; each R′ is independently hydrocarbyl having 1 to 20 carbon atoms in which O≦n≦8; M is a Group IVB transition metal or vanadium; and each Q is hydrocarbyl having 1 to 20 carbon atoms or halogen; the metallocene having a centroid-M-centroid angle in the range 105° to 125°.

Abstract: The analog fuzzy logic controller includes a fuzzification circuit by which the position and the shape of the membership functions associated with the linguistic input variables may be adjusted in an analog manner from outside. The output signals corresponding to the fuzzy values of the fuzzification circuit are supplied to an inference circuit. The output of the inference circuit is provided with a plurality of analog multiplex circuits with which the association of a degree of membership of a fuzzy rule to one or a plurality of linguistic output variables may be influenced. The defuzzification circuit of the fuzzy controller, which receives the output signals from the inference circuit, then calculates the output signals of the fuzzy controller according to the center of gravity method.