URGENCY

Humidity of wood is an important technological quality in wooden manufacturing Industry, because the humidity is the main factor that determines the quality and strength of the production. Problems in the dimension of humidity are really urgent and up to date now. It requires new ideas and new ways of dimension. The most important issues lie in the field of accuracy in dimension. To create some useful, simple in exploitation, reliable and more or less precision instrument for the dimension of the humidity is requires detail studying of the subject under dimension and modern scientists theories which explain the presence of some properties of humid wood.

AIMS AND PROBLEMS

The main goal of the diploma is to choose the method for creation of the precision device (or system), which could measure the humidity of plane wooden plates below the hygroscopic limit (W<=30%), with maximal exactness, which is suitable for all technological standards in wooden industry.

This diploma is called to solve such problems as:

• Choose the method of humidity dimension in plane wooden plates;
• Build mathematical model of the humidity dimension of plane wooden plates according to preferring information qualities (dielectric constant);
• Research the influence of negative factors on the procedure of the humidity dimension in plane wooden plates;
• Construction of sensor;
• Construction of the structural and principal scheme of the humid dimension system;

POSSIBLE SIENTIFIC NOVELTY

This diploma is considered to make and explore new results:

• Mathematical model of humid dimension by dielectric constant;
• The influence of outside electric field on measures of capacitive sensor, dielectric penetration of wood and its humidity will be research [8];
• The influence of temperature on the mistakes in humidity dimensions will be research. The ways of decreasing temperature mistakes [7];
• Creation and analysis of sensor’s form, defining species of materials to make the device.

POSSIBLE SIENTIFIC NOVELTY OF THE RESEARCHES. Wood could have an absolute humidity is about 250%. Free humidity has much higher dialectical parameters in comparison with dry wood. During the interaction with it in adsorption processes and capillary condensation connected humid change its dialectical qualities as usual and leads to changes in dielectric qualities of wood. So that we could find the straight correlation between dielectric parameters of wood and its humidity. Dielectric parameters of the material should be defined while enclosing of outside electric field is influence [1]. In the diploma you'll find: the theoretically proved choice of the optimal outside electric field’s frequency , researches over the influence of temperature and density of wood on the information parameter. The valuation of influence anizotropy’s of wood during the dimension of the humidity.

POSSIBLE PRACTICAL IMPORTANCE

Increasing the quality and exactness of measures.

LIST OF UNDESIDED PROBLEMS AND AIMS

The most important problems now are:

• Proved choice of outside electric field’s frequency;
• Research the influence of temperature on the mistakes in humidity dimensions;
• Creation of the useful form of the sensor;
• Arising mistakes in the consequence of changes in the density of object;

PLANNED AND PERSONALLY FINDED RESULTS

1. The analytic survey of the existed methods of measures in the humidity of wood;
2. Results of the measures of humidity by dielectric method (f=1KHz) for coniferous wood and for oak-tree according to existed data [8] is analyzed;
3. Creation and description of the sensor;
4. Creation and description of the structural scheme of the humidity dimension devise.

SOURSES

1. Берлинер М.А. Электрические измерения, автоматический контроль и регулирование влажности. -2-е изд., доп. и переработ. - М.-Л.: Энергия, 1965. - 488с.
2. Лесотехническая академия "Технопарк ЛТА". Измерение влажности древесины приборами фирмы GANN (Германия), - СПБ.: 2002.
3. Музалевский В.И. Измерение влажности древесины. - М.:1976. - 119с.
4. Музалевский В.И. Комбинированные емкостные преобразователи влажности листовых материалов//Измерительная техника 1972.-№1. - С.73-74
5. Нетушил А.В., Жуковицкий Б.Я., Кудин В.Н., Парини Е.П. Высокочастотный нагрев диэлектриков и полупроводников. - М.: Госэнергоиздат, 1959. - 154с.
6. Пилопродукция и деревянные детали. Государственный стандарт ГОСТ 16588 – 91 (ИСО 4470 – 81).
7. Тареев Б.М. Физика диэлектрических материалов. - М.: Энергоиздат, 1982 – 320с.
8. Торговников Г.И. Диэлектрические свойства древесины. – М.: Изд-во Леспром, 1986 - 127с.