Department of Electrical and Computer Engineering Seminar Series

Application of Smart Electrodes to logs, for timber assessment and Joule Heating

Speaker

Dr Bill Heffernan

Institute

Electric Power Engineering Centre University of Canterbury

Time & Place

Fri, 09 Aug 2019 14:00:00 NZST in Link 309 Lecture Theatre

Abstract

Based on work carried out over the past few years, the EPECentre team is developing a Smart Electrode capable of determining the shape and structure of unseasoned logs, based on the electrical conductivity
distribution.

Since unseasoned timber’s electrical conductivity has a strong temperature dependence, the temperature distribution within a log can also be determined by the method – this is significant for two processes carried out within the timber industry:
1. Heat treatment for biosecurity of exported/imported logs
2. Log softening (known as “conditioning”) prior to veneer peeling for plywood and LVL manufacture
Finally, if sufficient electric field strength is applied across a log, Joule’s effect can be used to provide the heat treatment using the same electrodes.

Smart ElectrodeSmart Electrode

Figure 1. Modelled current distribution in the segments of a Smart Electrode applied to a typical radiata pine log, before and after Joule heating. The electrode has an overall diameter of 500mm, colour represents current per equal-area segment and trace represents actual segment current across a diameter. Left: 1000 segment electrode with isothermal “cold” log; Right: 500 segment electrode with “hot” log, just after Joule heating.

Biography

Senior Research Engineer
Principal Investigator – Joule Log Heat
Electric Power Engineering Centre
University of Canterbury