Non Fumigant Approach

Non-chemical quarantine treatments will be evaluated, such as hot and cold sterilisation.

Heat Sterilisation

log in rig

Heat Sterilisation Technology Video

The University of Canterbury’s Electrical Power Engineering Centre (EpeCentre) is developing heat sterilisation technology that applies electrical energy to logs. In principle, this is like converting a log into a ‘bar heater’ where the energy applied is converted directly to heat.

This technique is technically challenging but one that provides the most efficient long-term solution for controlling pests with heat.

heatsteril-fig1

The right hand board shows the actual surface temperature of a typical sapwood board after 390 seconds of Joule heating, while the left board shows the prediction of a simple computer model.

The results of the simple computer model (shown above left) give some idea of overall heat rise, but the model is unable to accurately predict the hot and cold spots. To do this a more complete Computational Fluid Dynamics (CFD) computer model is under development. This is the current focus of investigation and involves intense research on very small blocks of timber. Measurement of electrical and thermal parameters of many small timber samples is necessary to build up an accurate model of the range of variability of P. radiata logs.

Sealed test fixture for measuring electrical conductivity of small timber samples as a function of temperature

Sealed test fixture for measuring electrical conductivity of small timber samples as a function of temperature

Heat Sterilisation Technology Video

Contact: Dr Allan Miller

Cold Sterilisation

Scion is testing cold sterilisation of logs using an electron beam that converts electrical energy into x-rays to kill pest infestations. The same technology is applied in hospitals and veterinary clinics to treat cancerous tumours.

The use of electron beams over older gamma ray technology, does not involve a radioactive source. The critical factor that will determine the feasibility of this technology is the energy required to ensure the treatments penetrates to a depth sufficient to kill pests present in log.

Contact Dr Steve Pawson

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