Poster Moving the World by DH Final
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Radiofrequency (RF) heating was evaluated as an alternative to methyl bromide fumigation and conventional heat treatments for wood packaging material. RF heating was found to meet the ISPM-15 requirement of achieving 60属C within 30 minutes and could treat wood dimensions greater than 20cm. RF heating also resulted in more uniform and consistent heating compared to microwave heating, and faster heating times for dimensions over 6x6 inches. RF heating is a viable alternative for treating wood packaging material according to international standards.
Poster Moving the World by DH Final
- 1. Background Pallets move the world with several billions pallets (>90% wooden) in service worldwide More than $400 billion worth of US trade exported annually on wood pallets Untreated wood packaging material (WPM) a major pathway by which pests that infest wood spread among countries e.g. Asian longhorned beetle (ALB, Anoplophora glabripennis) and the emerald ash borer (EAB, Agrilus planipennis) Estimated urban impact of ALB in the US is the loss of 35% of total tree canopy cover and a value loss of $669 billion , while EAB threatens to eliminate most ash species from North America. ISPM-15 and its limitations ISPM-15 (International Standards for Phytosanitary Measure No. 15) adopted by the International Plant Protection Convention aims to significantly reduce the risk of pests moving in WPM used in international trade by the following treatments: Fumigation with Methyl Bromide-MB Heat treatment Conventional Heat treatment-HT (56C for 30min) Dielectric heating- DH (60C through wood profile for 1min) MB phasing out in line with Montreal Protocol while conventional heat-treatment is costly & time consuming (Fig.1) Dielectric heating (DH) includes microwave (MW) and radiofrequency (RF) heating. The major difference between them is frequency range: RF uses much lower frequencies (10 to 300 MHz) than MW (300 to 30,000 MHz) DH is a viable alternative for MB treatment but current ISPM-15 includes restrictions over its application on size of treatment load (< 20cm) and treatment time (within 30 min) A footnote in the annex to ISPM-15 also states that only MW has been proven to comply with the schedule of 60C for 1 min within the 30 min treatment time, which excludes RF as an approved treatment. Acknowledgments USDA-NIFA Methyl Bromide Transitions Grant Program (Grant 2012-51102-20208) Results Conclusions RF heating meets ISPM requirement of achieving 60C within 30 min and can be used as an approved treatment (Table1, Fig 3) RF heating can penetrate beyond the 20 cm dimensional limit (Table1, Fig 3) RF heating is more uniform, consistent and faster than MW heating, especially for dimensions greater than 6x6 (Fig 4 & 5) 1Manoj K Dubey, 1John Janowiak, 2Kelli Hoover, 3Ron Mack and 3Peggy Elder 1Dept. of Agricultural & Biological Engineering, 2Dept. of Entomology, Penn State University, 3USDA-APHIS Work in Progress Commercial scale RF trials in Forestville, NY Measurement of dielectric properties of various species of wood Comparative economic analysis of RF heating vs. conventional heating Extension activities to educate & promote adoption of RF technology 12 Objectives Comparisons of RF and MW heating at similar power settings to demonstrate: Ability of RF to treat beyond 20 cm dimension RF can meet requirement of achieving 60C through the wood profile within 30 min Superior heating uniformity and less time to achieve 60C (t60) through the profile of test specimens of varying dimensions using RF Experimental approach Cants of dimensions ranging from 4x4 to 10x10 prepared from white oak (Quercus alba)- most commonly used species for pallet construction in US Specimens drilled at mid-length and pre-fixed depth from wood surface for probes to monitor core temperatures (Fig 2-a, 2-b) Specimens heated in 19 MHz RF (Fig 2-c) and 2.45 GHz MW (Fig 2-d) lab ovens with similar power (3.4kW) till all probes recorded target temperature of 60C. Specimens processed for moisture content determination & thermal imaging analysis Further Information Dr John Janowiak, +1-814-865-3916, jjj2@psu.edu Cant size (inch) Heatin g Depth t60 (min) Moisture Content % Moisture loss % (cm) RF MW RF MW RF MW 4x4 9 4 4 61 65 0.5 1.6 5x5 11 11 7 59 66 0.7 1.1 6x6 14 10 11 69 61 0.8 1.5 8x8 19 20 34 67 54 0.5 6.4 10x10 24 30 54 62 58 N/A N/A 0 20 40 60 80 100 120 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 T(属C) Distance from Top surface (inch) T (Final temp - Start temp) with heating depth in 8x8 cant RF MW 0 10 20 30 40 50 60 9 11 14 19 24 t60(min) Heating Depth (cm) Time to achieve 60C at varying heating depth RF MW ISPM-15 DH Treatment Time Limit Fig.1 Fig.2-a Fig.2-dFig.2-c Fig.2-b Fig.3 Fig.4 Fig.5 Table 1 Key references FAO (2013). ISPM-15: Regulation of wood packaging material in international trade. Rome, International Plant Protection Convention-IPPC, Food and Agriculture Organization of the United Nations Strutt, A., J. A. Turner, L. Garrett, R. A. Haack, and L. Olson (2013). Evaluating the impacts of an international phytosanitory standard for wood packaging material: Global and United States implications. Forest Policy and Economics 27:5464.