Couplings universal joints

Jackshafts Some machine-trains use an extended or spacer shaft, called a jackshaft, to connect the driver and a driven unit. This type of shaft may use any combination of flexible coupling, universal joint, or splined coupling to provide the flexibility required making the connection. Typically, this type of intermediate drive is used either to absorb torsional variations during speed changes or to accommodate misalignment between the two machine-train components. 

Couplings Regular Misalignm. couplings W. or w/o. roll timing Universal joint... 

The shaft size defined two viable options for the rock hoist arrangement in terms of acceptable rope fleeting angles namely, either an electrically coupled hoist or a hoist with a Hookes Joint (Universal Joint) to allow the drums to be angled relative to each other. 

Acknowledgements TS gratefully acknowledges Prof. Arnout Ceulemans and Prof. Liviu F. Chibotaru for valuable discussions on the dynamic Jahn-Teller problem and vibronic couplings in fullerene ions. Numerical calculation was partly performed in the Supercomputer Laboratory of Kyoto University and Research Center for Computational Science, Okazaki, Japan. This work was supported by Grant-in-Aid for Scientific Research (C) (20550163), Priority Areas Molecular theory for real system (20038028) from Japan Society for the Promotion of Science (JSPS), and the JSPS-FWO (Fonds voor Wetenschappelijk Onderzoek-Vlaanderen) Joint Research Project. 

The sheer size and value of the polyethylene industry ensure that there is continued research, progress, and development in catalysis, for their potential commercial impact. Although this whole subject is not within the scope of this chapter, we mention a couple of aspects of the progress, which offer the potential to impact this industry. In 1995, DuPont introduced work, carried out with them at the University of North Carolina—via the largest patent applicafion ever in the USA. They disclosed what are described as post-metallocene catalysts. These are transition and late transition metal complexes with di-imine ligands, which form part of the DuPont Versipol technology. Such catalysts create highly branched to exceptionally linear ethylene homopolymers and linear alpha-olefins. Late transition metals offer not only the potential for the incorporation of polar comonomers, which until now has only been possible in LDPE reactors, but also their controlled sequence distribution, compared to the random composition of free radical LDPE copolymers. Such copolymers account for over 1 million tons per annum [20]. Versipol has so far only been cross-licensed and used commercially by DuPont Dow Elastomers (a former joint venture, now dissolved) in an EPDM plant. 

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