Data quality assurance controls through the WIPP (Waste Isolation Pilot Plant) In Situ Data Acquisition, Analysis, and Management System

Assurance of data quality for the in situ tests fielded at the Waste Isolation Pilot Plant is of critical importance. These tests supply the information for development and verification of the technology required for construction of a radioactive waste repository in bedded salt. The tests are some of the largest ever fielded in an underground facility. To assure that the extensive output generated by the tests is compatible with the high standards of quality required, a major project task was undertaken for the acquisition, control, and preservation of the all the associated in situ test databases, with the principal emphasis on the very large thermal/structural in situ tests. In order to accomplish this task the WIPP In Situ Data Acquisition, Analysis, and Management (WISDAAM) System was put into place. The system provides for quality control of the test databases and certified test data throughout the duration of the tests. 13 refs., 14 figs., 3 tabs

A novel industrial technique for recycling ethylene-propylene-diene waste rubber

This paper was accepted for publication in the journal Polymer Degradation and Stability and the definitive published version is available at http://dx.doi.org/10.1016/j.polymdegradstab.2014.11.003© 2014 Elsevier Ltd. All rights reserved.Recycling waste rubber has gained importance in recent years. Ethylene-propylene-diene rubber (EPDM) is used to manufacture various automotive parts. Reclaiming EPDM rubber waste is a major problem. Waste powder from discarded EPDM automotive parts was devulcanized using an industrial autoclave which provided both heating and high pressure steam. To aid the devulcanization process, 2-mercaptobenzothiazoledisulfide (MBTS) and tetramethylthiuram disulfide (TMTD) devulcanizing agents, and aromatic and aliphatic oils were also used. A portion of the virgin EPDM rubber in a common formulation for the automotive rubber strips was replaced with the devulcanized product to produce blends, which were revulcanized using a semi-efficient (SEV) vulcanization system. The viscosity, cure and mechanical properties of the blends were subsequently determined. This study showed that the oils had different effects on the devulcanization of the waste powder and MBTS was more efficient than TMTD. Replacing 60 wt% of the virgin rubber in the automotive rubber strips with the devulcanized powder had no adverse effect on the scorch and optimum cure times, crosslink density, rate of cure, and viscosity. Also, when 20 wt% of the virgin rubber was replaced, the hardness, compression set, and modulus at 20% elongation were unaffected. It was concluded that the reclaimed rubber could be used in low percentage in order not to extremely deteriorate the mechanical properties of the virgin rubber. This provided a new effective recycling route for the waste EPDM powder in the automotive rubber strips