RESEARCH OF THE COMPOSITION OF PRODUCTS OF MICROWAVE PYROLYSIS OF WOOD

A method of microwave action on wood of various species was developed, as a result of which the pyrolysis process was carried out. Allocated solid, gaseous fractions, as well as as a result of condensation of a vapor-gas mixture, pyrolysate, which is a raw material for the production of low molecular weight organic compounds of various classes. Gas chromatography-mass spectroscopic analysis of the liquid fraction was carried out, the components included in its composition were identified. The proposed method allows liquefaction of wood for 20-30 minutes in the temperature range from 230 to 423 °С.

Microwave-Assisted Enzymatic Extraction of Flavonoids from Armeniaca mume Sieb. Blossom and Their Immunomodulating Effect in Mice with DSS-Induced Colitis

Armeniaca mume Sieb. blossom is among the traditional Chinese edible flowers, and it is widely used in the food and pharmaceutical industries. Flavonoids are among the most abundant bioactive compounds in A. mume Sieb. blossom. However, the research on the extraction of flavonoids from A. mume Sieb. blossom and their immunomodulating function is insufficient. In this study, we developed a microwave-assisted enzymatic extraction of flavonoids from A. mume Sieb. blossom (FAMB) and explored their immunomodulating effect on mice with dextran sulfate sodium salt-induced colitis. The results showed that the optimum parameters for microwave-assisted enzymatic extraction of FAMB were as follows: cellulase: 2.0%; microwave power: 200 W; microwave action time: 5 min; and enzymatic hydrolysis time: 50 min. FAMB significantly promoted the lymphocyte proliferation and natural killer (NK) cell killing activity in colitis mice, and increased the concentrations of TNF-α, IFN-γ, and IL-2 in serum. FAMB also significantly reduced the apoptosis of spleen lymphocytes in these mice. These results demonstrated that the microwave-assisted enzymatic method could significantly improve the yield and efficacy extraction of FAMB. FAMB showed a good immunomodulation effect on colitis mice.

Study on the Thermodynamic Properties of Concrete Surface during Microwave Deicing of Airport Pavement

In the cold belt area, the icing phenomenon often appears on the airport pavement, which affects the safety of aircraft take-off and landing. Microwave deicing technology can effectively solve this practical problem and has many advantages. Taking microwave deicing technology as the research object and the surface temperature of pavement concrete as the index, an open microwave test system has been established in this paper. Based on this system, the temperature distribution, variation rule, and influencing factors of concrete have been studied systematically. The results show that the surface temperature of concrete increases linearly due to microwave action. In addition, during the microwave action, the temperature increase of the concrete surface is centered on the center point and shows a stepwise decreasing trend along the radius. At the same time, the increase of microwave source height leads to the increase of surface temperature distribution uniformity. The surface ice affects the rate of temperature increase of concrete in stages under microwave action, and the surface edge area remains frozen for a certain period of time. The temperature distribution of concrete surface is a decisive factor affecting the degree of ice removal, and the concrete surface will generate residual heat after the microwave action ends. This phenomenon can delay the regression of the temperature distribution of the concrete surface, thus effectively preventing the re-freezing of the ice layer.

The Effect of Microwave on the Physical and Chemical Properties of Cassava Starch

Starch is a kind of natural polymers and belongs to the renewable resources. Starch grain in the interior has crystallization area and non-crystalline area where the chemical reactions occur. In this paper, the effect of microwave cassava starch on the physical and chemical properties and characterizated by infrared spectrum and scan electrical microscope (SEM) was investigated. The transparency increase, the viscosity reduce and the anti-sedimentation enhanced after microwave action on tapioca starch. The result of infrared spectrum and scan electrical microscope shows that the original basic structure of cassava starch by microwave has not been damaged but the crystalline structure has been destroyed, which results in the reducing of the crystallinity of starch, the increasing of the contact area of particles and reaction reagents and the improving of the reaction activities .