Editor’s message: experiments with microwave kitchen ovens

Abstract

A noticeable number of manuscripts present results of experiments conducted with arrangements based on microwave kitchen ovens for different applications. The use of this kind of ovens is attractive due to its accessibility and low cost, and with several modifications performed by the researchers, such as altering the cavity or instrumentation, there is no doubt about their usefulness in many cases. Although their operation is simple, one problem is that their nominal power is not always accurate, which in regular household applications is not an issue. Still, there are reports of meals that do not reach the necessary temperature to ensure killing bacteria, even following directions on the packets, because the meal amount and processing time are set accordingly to a power value that could be lower than expected. Other microwavable items, such as heat pads, infant formulas, and depilatory wax, are heated in these ovens, and if the opposite occurs, then overheating is also possible. When these ovens are in laboratory experimental arrangements, it is necessary to consider that microwave power varies even under service, so that sometimes only short tests with long cooling times between them are appropriated so that a given power condition is reproducible. Even so, real magnetron power is unknown while often the nominal value is reported as the applied power, without considering losses or cavity geometry. It is quite acceptable to conduct this kind of simple test for comparison purposes or confirming if a material can be heated or not with microwaves. However, often that it should, details regarding power stability, reliability and the nature of the performed changes in the ovens are not reported in the manuscripts, therefore, drawing conclusions or validating parameters related to power from these experiments is questionable. This journal is aimed at non-communication applications of microwaves and RF, meaning that they are employed for purposes such as drying, extracting, and cooking, among others, intended towards industrial-scale or mass production. Indeed, the kitchen oven is a response to the demand for fast food and it is one of the most representative non-communication applications of microwaves. Foundations of microwave engineering for design of systems and devices for processing materials and substances are given by multidisciplinary sciences and arts, that include studies on interaction matter-wave, transport phenomena, materials science, as well as knowledge about the physical, chemical, and biological nature, if applies, of the substances. The development of applications always requires experimentation, and the microwave kitchen oven is quite available, hence there are excellent examples of its application for researching. Then, mention of its limitations is not against this use, yet it is not acceptable to overrule them and formulate conclusions about kinetics and efficiency issues without discussing the modifications, limitations, and true knowledge of the processing conditions. The best journal papers are not necessarily based on the use of the most sophisticated or expensive equipment. The purpose of the research tells the kind of equipment and