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CNAA / Theses / 2006 / June /

Theoretical and experimental research of the drying process of sea-buckthorn by using current of high frequency

Author: Marcel Răducan
Degree:doctor of engineering
Speciality: 05.18.12 - Food industry processes and equipment
Scientific advisers: Andrei Lupaşco
doctor habilitat, professor, Technical University of Moldova
Mircea Bernic
doctor habilitat, professor, Technical University of Moldova
Scientific council:


The thesis was presented on the 9 June, 2006
Approved by NCAA on the 29 June, 2006


Adobe PDF document1.07 Mb / in romanian


CZU 664.854:634.21:621.3.023

Adobe PDF document 2.26 Mb / in romanian
156 pages


sea-buckthorn, drying, convection, currents of high frequency, electromagnetic field, temperature, tension


The candidate thesis is for getting a scientific degree in technical science on speciality 05.18-12 – Processes and equipment for food processing industry, Technical University of Moldova, Chisinau 2006.

The thesis is written as a monography.

There are 22 scientific works defended, including 3 Republic of Moldova patents and one request in obtaining a patent, which presents the result of the theoretical and experimental researches on intensifying the drying process of the sea-buckthorn by usage of combined energy transfer – convection +UHF.

There are determined the electro physical parameters tgδ and ε’ of sea-buckthorn and their dependence on electromagnetic field frequency, temperature and product’s humidity. It is determined the frequency of electromagnetic field for thermal treatment of sea-buckthorn-27 MHz.

There is presented the experimental research of the kinetic process of sea-buckthorn drying by using combined energy transfer - convection + UHF.

Basing on the carried out researches it is determined that the drying process of sea-buckthorn, in the case of using combined connection, should be done in two phases. In the first phase the sea-buckthorn should be dried only by means of convection when reaching the humidity of 25%. In the second phase starting with W3 = 2%, the sea-buckthorn should be dried by means of combined energy transfer – convection +UHF. At the same time the temperature of drying agent should be 1000 C of electromagnetic field E = 28.2 kW/m.

For the first time it is elaborated the mathematical model of calculating differential equations of thermo-mass resistance in the case of sea-buckthorn drying with internal heat source for variant “sphere” in “sphere”.

Checking on adequacy gave deviation 5-15%, which is permitted.

Economical effect in implementation of the proposed devices is 4464.55 lei.