Historical review of die drool phenomenon in plastics extrusion

Die drool phenomenon is defined as unwanted spontaneous accumulation of extruded plastics on die exit face(s) of extrusion die during plastics extrusion process. Such accumulated material builds up on die exit face(s) and frequently or continually sticks onto the extruded product and by this way reduces the quality of the product. When the die drool appears, the extrusion process must be shut down and the die exit face(s) must be manually cleaned, which is time consuming as well as money consuming. Die drool has been observed from the beginning of plastics extrusion and the first published remark about it was made in 1946. For a long time it was considered as only an engineering problem and even if a wide range of suppressing ideas based on modification of extrusion dies, plastics materials, and processing conditions have already been patented, its source remained unclear. During the last few years, a number of experimental as well as theoretical research papers focusing on its fundamental nature have been published. Nowadays, die drool is considered as a fundamental rheological phenomenon. The force which drives the building up of extruded plastics on die exit face(s) is negative pressure (suction) occurring in the die exit edge(s) region where the free surface of the extruded plastics is created. Moreover, two different die drool types (external and internal) exist. The formation mechanisms of external/internal die drool are based on negative pressure occurring in the die exit region together with deformation of free extrudate surface/material separation wherever inside the extrusion equipment, respectively. From the processing point of view, the internal die drool is much more problematic than the external one, primarily due to a higher build up rate and compact shapes of the accumulated drool mass. Two theories of internal die drool formation mechanism based on wall slip theories (flow-induced molecular weight fractionation and stress-induced cohesive chain disentanglement) have been recently proposed and tested. In this historically ordered review, breakthrough works in the field of die drool research are presented, many ways to suppress it are shown, techniques for its quantitative evaluation and experimental methods for its analytical investigation are introduced, external and internal die drool types are explained, and theories of external as well as internal die drool formation mechanism are presented and discussed in depth, which can be especially helpful for plastics extrusion experts as well as for the rheological community. © 2014 Taylor and Francis Group, LLC

In Search of Copyright’s Lost Ark: Interpreting the Right to Distribute in the Internet Age

Prior to the emergence of peer-to-peer technology, the Copyright Act’s distribution right was largely dormant. Most enforcement actions were premised upon violations of the reproduction right. The relatively few cases invoking the distribution right involved arcane scenarios. During the past several years, direct enforcement of the Copyright Act against file sharers has brought the scope of the distribution right to center stage. Whereas the 1909 Act expressly protected the rights to “publish” and “vend,” the 1976 Act speaks of a right to “distribute.” Interpreting “distribute” narrowly, some courts have held that copyright owners must prove that a sound recording placed in a peer-to-peer share folder was actually downloaded to establish violation of the distribution right. Other courts hold that merely making a sound recording available violates the distribution right. The ramifications for copyright enforcement in the Internet age are substantial. Under the narrow interpretation, the relative anonymity of peer-to-peer transmissions in combination with privacy concerns make enforcement costly and difficult. A broad interpretation exposes millions of peer-to-peer users to potentially crushing statutory damages. Drawing upon the historical development of copyright law and the legislative history of the Copyright Act of 1976, this article explains why Congress selected the term “distribute” in its last omnibus revision of copyright law, shows unequivocally that Congress intended to encompass broadly the 1909 Act rights to “publish” and “vend” within the right to distribute, and rejects the position that Congress required proof of “actual distribution” to prove violation of the distribution right. This critical legislative history has been notably absent from treatise accounts and briefing on the liability standard in the file sharing cases, leaving courts without a compass to navigate this statutory terrain. This article traces the origins of the key legislative terms to elucidate the scope of the distribution right in the Internet age