[en] CEA has developed and tested a new heating system based on mono mode stationary microwaves, which allows a regular distribution of heat. Hot or cold points are avoided. This system is used for waste vitrification, particularly in the ''cold crucible'' technique. Sintering processes, elaboration of ceramics, fusion of oxides could benefit by this heating system. (A.C.)

[en] Microwave heating has been proposed as a technique for ceramic joining. The proposal is based on the selective absorption of microwave energy by materials according to their dielectric loss properties. There have been a few examples of ceramic-ceramic joining using microwave heating, but the method is largely undeveloped. This paper reviews the materials and processing requirements for ceramic joining and to what extent they are met by microwave heating. Some microwave properties, such as rapid heating rates, are undesirable for ceramic joining. Others, such as the possibility of selectively heating buried interfaces, may be an advantage. Much more work needs to be done to assess the relative merits of microwave heating for this application. 22 refs., 5 figs., 1 tab

[en] Continuous vulcanization is being increasingly used today in the manufacture of extrusion profiles. This is particularly so with the microwave/hot air continuous vulcanization process. Although this process is now quite widely used in Europe and to a lesser extent in USA, it is still not used in Malaysia. To improve the technological capability of the rubber-based industry in extrusion product, the RRIM has acquired a microwave/hot air tunnel continuous vulcanization equipment to enable development work in this area to be carried out with the aim of upgrading the rubber industry towards this more automated manufacturing process. This is particularly pertinent in view of the anticipated labour shortage, and, increasing labour and energy cost. This paper outlines the basic principles of operation of the microwave/hot air tunnel continuous vulcanization process and describes some aspects of compounding involving natural and synthetic rubbers for use in the process. As temperature increase is one of the major factors influencing the vulcanization of profile in this process, study was therefore concentrated on the heat generation aspect in the microwave tunnel

[en] The objective was to clarify from the theoretical viewpoint the mechanical, diffusional, thermodynamic and electromagnetic aspects of the decontaminations problem, by means of developing a powerful computational model to evaluate the effect of a very rapid heating regime on the on the contaminated concrete walls or slabs. The practical objective was to assess the feasibility of the microwave heating scheme envisaged and determine its suitable parameters such as power and duration. This objective was complementary to, but separate from, the chemical and nuclear aspects of long-time processes that led to the contamination and various conceivable alternative methods of decontamination which were investigated by Dr. Brian Spalding of Oak Ridge National Laboratory, with whom the start-up phase of this project was coordinated

[en] The comparative results obtained by applying separate beam irradiation, separate microwave heating and combined electron beam irradiation and microwave heating (successive and simultaneous) to reduction of viable cells of Staphylococcus intermedius and Pseudomaonas aeruginosa are presented. Simultaneous irradiation results in a more dramatic reduction of microorganisms than by either microwave or electron beam irradiation alone. The tests demonstrated that irradiation time and the upper limit of required absorbed dose which ensures a complete sterilization effect of the studied microorganisms could be reduced of about six times by additional use of microwave energy to electron beam irradiation. Experiments were carried out using an electron linear accelerator ALIN-10 of 6 MeV and 180 W maximum output power and 2.45 GHz microwave source of controlled power up to 0.85 kW. (authors)

[en] Lanthanum-substituted SrBi_4Ti_4O_1_5 (SBTi) ceramic, that is SrBi_4_-_xLa_xTi_4O_1_5 (SBLTi), samples were calcined by solid-state reaction and densified using the microwave sintering and conventional sintering techniques. Their structural, morphological and mechanical properties were investigated. The microwave sintered samples showed high densities like 95% of the theoretical density with short duration exposures. Compared with SBTi ceramics and other lanthanide-substituted compositions, the incorporation of La"3"+ results in clear improvement in properties for SBLT (x∼0.75) with respect to the values of hardness and Young's modulus of the microwave sintered samples (8.8-12.5 and 160-180 GPa) are higher than that for conventional sintered (8-10 and 135-155 GPa) samples. (author)

[en] Microwave energy has become a sound method of heat treatment because of its high penetration power, cleanliness and possible economic significance. In this research, microwave heat was used as a substitute for conventional blanching method of palm oil fruits. Microwave treatment at 2450 MHz and 800 watts gave very close color and frn,frying characteristics to oil of blanched fruits after one minute exposure time. However, five minutes of microwave heat gave severe husk oil discoloration after 49 hours of deep frying, compared to all oils extracted from fruits treated by either low, microwave exposure time or conventional steam treatment. Kernel oil, after five minutes of microwave treatment, was less discolored than both steam or microwave-treated fruits for one minute. More carotenes and discoloration compounds may be contributed to discoloration during microwave treatments. Oil chemical constants of both husk and kernel oils treated by microwave heat were close to those treated by conventional heat. Further research is needed to investigate detailed oil characteristics and evaluate the feasibility study for using microwave energy, as a substitute for conventional heat in palm oil industry

[en] Three coordination polymers, [ML₂(H₂O)₂] (M = Co (1), Ni (2), Mn (3)), were prepared from metal acetates (M(CH₃COO)₂·4H₂O) and 3-pyridinepropionic acid (HL = (3-py).CH₂CH₂COOH) by solvent-layer methods. By contrast, a discrete molecular compound, trans-[Pd(HL)₂Cl₂] (4), was synthesized by replacing benzonitrile (PhCN) ligands in trans-[Pd(PhCN)₂Cl₂] with HL under microwave-heating conditions. Compounds 1-3 have a 2D framework, and compound 4 contains a square-planar Pd metal

[en] Data on the synthesis of individual and multicomponent oxides from salts with microwave initiation published over the last 15 years are analysed. The advantages and drawbacks of using microwave heating in the synthesis of oxide materials are noted. Criteria for the selection of chemical systems for microwave heating are proposed.

[en] An efficient and green procedure for the synthesis of purine acyclic nucleosides through microwave-assisted alkylation of various purine nucleobases with 2-oxa-1,4-butanediol diacetate in the absence of solvent and catalyst is described. The advantages of using this method include its environmental friendliness, simple manipulation, short reaction time, high regioselectivity, and good yields. (author)