In this article, the author investigates the change of weight and temperature of pine cones in a microwave oven over the following range of microwave irradiation power (PMF): 800, 620, 440, 260 and 130 W.
Cones were divided into groups according to their weight and the author examined the influence of PMF on their water content and drying rate. The process is described with the help of mathematical equations and curves. The cones were irradiated in the microwave until all cones of the given group began to open the first scales. Small cones required longer exposure times to PMF than medium and large cones in order to cause scale opening. The most efficient of the five settings was a irradiation power of 620 W with an exposure time to microwaves for no longer than 20 seconds.
In the second part of the study, the author analyses the changes of temperature on the cone surface using a thermal imaging camera. The values of surface temperature depended on irradiation power and the duration of irradiation.
Copper oxide and cobalt oxide (Co3O4, CuO) nanocrystals (NCs) have been successfully prepared using microwave irradiation. The obtained powders of the nanocrystals (NCs) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric (TGA) analysis and Fourier-transform infrared spectroscopy. The obtained results confirm the presence of both nanooxides which have been produced during chemical precipitation using microwave irradiation. TEM micrographs have shown that the obtained nanocrystals are characterized by high dispersion and narrow size distribution. The results of X-ray diffraction confirmed those obtained from the transmission electron microscope. Optical absorption analysis indicated the direct band gap for both kinds of the nanocrystals.
Kamila Widziewicz, Krzysztof Loska and Wioletta Rogula-Kozłowska
Presented study aimed to determine metals distribution on the quartz fiber filters surface coated with particulate matter by using high and low-volume samplers. The distribution pattern was tested using two different sub-sampling schemes. Each sub-sample was mineralized in the nitric acid in a microwave oven. An analysis was performed by means of atomic absorption spectroscopy with electrothermal atomization GF-AAS technique, and the determined elements were: As, Cd, Pb and Ni. A validation of the analytical procedure was carried out using NIES 28 Urban Aerosols standard reference material.
It was assumed that metal is distributed uniformly if its normalized concentrations on a single sub-sample is within ±15% of the mean concentration over the whole filter. The normalized concentrations values exceed this range, indicating a non-homogenous metals distribution. There were no statistically significant differences in metals concentrations between particular sub-samples in the function of its position along the filters diameter.
Agnieszka Filipiak-Florkiewicz, Adam Florkiewicz, Ewa Cieślik, Izabela Wałkowska, Maria Walczycka, Teresa Leszczyńska and Joanna Kapusta-Duch
Effects of Various Hydrothermal Treatments on Selected Nutrients in Legume Seeds
The aim of this study was to assess the influence of different soaking and cooking methods on contents of selected nutrients in legume seeds. The experimental material were dried kidney-bean seeds and soya bean seeds originating from the collection of Krakow's Plants and Seeds Horticulture POLAN LTD. Technological treatment of seeds was performed in two stages: (1) cold and hot soaking, (2) cooking with three different devices: electric and induction stoves and microwave apparatus. The experimental material was determined for contents of: dry matter, protein, fat, ash, carbohydrates and selected mineral compounds (Ca, Mg, Na, K). The soaking and cooking of the seeds were observed to affect an increase in contents of protein, fat, ash, calcium and sodium in dry matter as well as a decrease in contents of digestible carbohydrates, potassium and magnesium. A more favorable method of soaking kidney bean seeds turned out to be hot soaking, which caused smaller losses of nutrients and shortened significantly the whole process. Cooking soya bean and kidney bean seeds with electric and induction stoves facilitated better protein preservation in comparison to the thermal treatment performed in a combined microwave oven.
Reza Tajik, Hasan Asilian Mohabadi, Ali Khavanin, Ahmad Jonidi Jafari and Babak Eshrati
Polychlorinated biphenyls (PCBs) are one group of persistent organic pollutants (POPs) that are of international concern because of global distribution, persistence, and toxicity. Removal of these compounds from the environment remains a very difficult challenge because the compounds are highly hydrophobic and have very low solubility in water. A 900 W domestic microwave oven, pyrex vessel reactor, pyrex tube connector and condensing system were used in this experiment. Radiation was discontinuous and ray powers were 540, 720 and 900 W. The PCBS were analyzed by GC-ECD. The application of microwave radiation and H2O2/TiO2 agents for the degradation of polychlorinated biphenyl contaminated oil was explored in this study. PCB – contaminated oil was treated in a pyrex reactor by microwave irradiation at 2450 MHz with the addition of H2O2/TiO2. A novel grain TiO2 (GT01) was used. The determination of PCB residues in oil by gas chromatography (GC) revealed that rates of PCB decomposition were highly dependent on microwave power, exposure time, ratio to solvent with transformer oil in 3:1, the optimal amount of GT01 (0.2 g) and 0.116 mol of H2O2 were used in the study. It was suggested that microwave irradiation with the assistance of H2O2/TiO2 might be a potential technology for the degradation of PCB – contaminated oil. The experiments show that MW irradiation, H2O2 oxidant and TiO2 catalyst lead to a degradation efficiency of PCBs only in the presence of ethanol. The results showed that the addition of ethanol significantly enhanced degradation efficiency of PCBs.
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