Thesis (M.S.)--Ohio University, March, 1981. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, August, 1989. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, June, 1989. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, March, 1990. / Title from PDF t.p.

No description available.

No description available.

Thesis (M. Phil.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 129-134). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Includes bibliographical references (leaves 129-134). Also available on the Internet.

In the extrusion blow molding process the shape and thickness distribution of the finished container depend on the dimensions of the parison at the time of inflation. In particular, the processes of swell and sag act to cause a variation of parison dimensions between the time the melt emerges from the die and the moment of inflation. / In the present study the effects of die geometry, extrusion velocity and the rheological properties of the resin on parison behavior were studied. Four annular dies (a straight, a diverging and two converging dies) and three high density polyethylene resins were used. To study the individual contributions of swell and sag to the overall parison behavior, two types of experiments were carried out. First, swell was studied in the absence of sag by extruding the parison into an isothermal oil bath. Both diameter and thickness swells were measured as functions of time. Then combined effect of swell and sag was studied by extruding the parison into an isothermal air oven. / A simple lumped parameter model was developed to predict the length of the parison using the swell data, storage modulus and process variables.