| Heat treatment for wood packing material is a general international approach, all countries should refer to the implementation according to the requirements of the International Standards for phytosanitary Measures-the management standard for wood packing material in international trade [ISPM No.15publications]. The standard was approved in March2002, re-revised and released in2009. The requirement of the standard is "the whole of wood materials (including wood material center) reaches the minimum temperature of56℃and lasts at least30minutes". However, it is difficult to implement the standard to the enterprises taking up producing and supervisory departments. First, how do we measure scientificly that the whole of wood materials (including wood material center) reaches the minimum temperature of56℃, second, what is the theoretical ground for judging it, third, whether datum measured are representative in massive production process, and whether they ensure that the treatments are effective. At present, in order to ensure the actual effect of heat treatment, enterprises adopt respectively their own heat treatment methods conforming to or toping the standard., but it has no adequate theoretical basis, so waste time and production costs. In the paper, through the study on the application of mathematical model of environmental parameters as heat treatment for wood packing materials, the reliable theoretical basis was provided for enterprises, its main research results and innovation points are as follows:(1) By the systematic study on ten factors impacting wood material center temperature, it made sure that timber thickness, moisture content, heat temperature and ambient humidity are as the main influence factors, at the same time, the above key factors linked the actual production were quantified, the mathematical model software based on theoretical formulas was first developed, so that the heat treatment for wood packing materials was more scientific and easier to operate. In the study, the database for the theory and test of heat treatment was established, it integrated domestic and foreign research datum, and provided a more systematic database platform for future research.(2)By the study on heat treatment for pine wood nematodes in wood packing materials, under the experimental conditions, the lethal temperature and lasting time were60℃and30min, they were higher than the requirements of ISPM15, this provided a reference for revising international standards for the future.(3) By the study on lethal temperature of M.alternatus Hope stages, it made sure that the stage with highest duration on the ambient temperature was chrysalides, and the result drew was that highest duration temperature was54℃,30min.(4) The measuring and calculating software based on the mathematical model of environmental parameters of heat treatment for wood packing materials was developed by ourselves, and it made the measure and calculation of wood material center temperature scientific, rapid and accurate.(5)The recorder of wood material center temperature was developed by ourselves and patented, and it made the temperature measure in enterprises and supervisory departments more accurate and scientific.(6) By a series of practice and test on the software based on the mathematical model of theoretical formulas, the treatment time by the software calculateion was effective, and saved time and cost for enterprises, so it had an important practical production significance.The software will be further exploited in the future, the background test-theory database will be developed. The database continues to be expanded and improved, it can not only improve the accuracy of the model software measuring temperature, but also provide a reliable theoretical basis for supervisory departments, provide a more accurate treatment time for enterprises, and provide a reference for the amendment of the ISPM15, international publications. |
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