scholarly journals Heating Device Based on Modified Microwave Oven: Improved to Measure Liquid Temperature by Using FBG Sensors

Photonics ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 104
Author(s):  
Jesus Garavito ◽  
Carlos Galvis ◽  
Ana Milena López ◽  
Arlet Patricia Franco ◽  
Francisco Barreiro ◽  
...  

A prototype device based on a modified domestic microwave oven for liquid food products pasteurization is presented. This novel design has a coiling glass pipe adapted inside a microwave cavity to allow liquid continuous flow, in which several temperature optical sensors based on Fiber Bragg Grating were installed to measure, by means of contact, the circulating liquid temperature in the pipe, while the oven is on, to obtain the profile temperature as a function of time at different pipe points. The temperatures at liquid input and output were also measured with thermocouples. This device was tested to establish how well it may perform using different standardized liquids with well-known physicochemical and dielectric properties, such as water, water with dissolved sugars, water with dissolved salts, and water with dissolved sugars and salts. It could be observed that the maximum temperature reached was 90 °C for distilled water, 80 °C for water with dissolved salts, 60 °C for water with dissolved sugars and 80 °C for water with dissolved sugars and salts, showing that these data were in agreement with previous results in the literature. This type of device would be potentially useful to establish the device’s efficiency in terms of retention time, energy consumption, and volume of processed liquid, thus, broadening the use of this microwave heating technology with several types of liquid substances.

2012 ◽  
Vol 478 ◽  
pp. 56-59 ◽  
Author(s):  
J.B. Silveira ◽  
C.L. Carvalho ◽  
G.B. Torsoni ◽  
H.A. Aquino ◽  
R. Zadorosny

2013 ◽  
Vol 433 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Elena Frisch ◽  
Christian Schwedler ◽  
Matthias Kaup ◽  
Elena Iona Braicu ◽  
Jörn Gröne ◽  
...  

1993 ◽  
Vol 279 (2) ◽  
pp. 273-279 ◽  
Author(s):  
Miguel-Angel Mateo ◽  
Santiago Sabaté

2010 ◽  
Vol 45 (11) ◽  
pp. 1703-1706 ◽  
Author(s):  
F.V. Motta ◽  
R.C. Lima ◽  
A.P.A. Marques ◽  
E.R. Leite ◽  
J.A. Varela ◽  
...  

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2281 ◽  
Author(s):  
Anne-Katrin Mahlein ◽  
Elias Alisaac ◽  
Ali Al Masri ◽  
Jan Behmann ◽  
Heinz-Wilhelm Dehne ◽  
...  

Optical sensors have shown high capabilities to improve the detection and monitoring of plant disease development. This study was designed to compare the feasibility of different sensors to characterize Fusarium head blight (FHB) caused by Fusarium graminearum and Fusarium culmorum. Under controlled conditions, time-series measurements were performed with infrared thermography (IRT), chlorophyll fluorescence imaging (CFI), and hyperspectral imaging (HSI) starting 3 days after inoculation (dai). IRT allowed the visualization of temperature differences within the infected spikelets beginning 5 dai. At the same time, a disorder of the photosynthetic activity was confirmed by CFI via maximal fluorescence yields of spikelets (Fm) 5 dai. Pigment-specific simple ratio PSSRa and PSSRb derived from HSI allowed discrimination between Fusarium-infected and non-inoculated spikelets 3 dai. This effect on assimilation started earlier and was more pronounced with F. graminearum. Except the maximum temperature difference (MTD), all parameters derived from different sensors were significantly correlated with each other and with disease severity (DS). A support vector machine (SVM) classification of parameters derived from IRT, CFI, or HSI allowed the differentiation between non-inoculated and infected spikelets 3 dai with an accuracy of 78, 56 and 78%, respectively. Combining the IRT-HSI or CFI-HSI parameters improved the accuracy to 89% 30 dai.


1987 ◽  
Vol 22 (1) ◽  
pp. 41-47 ◽  
Author(s):  
T. K. Ishii ◽  
M. R. Wolski ◽  
M.M. Ishii

Author(s):  
Naveen Kumar Garg ◽  
Amit Pal

A novel and rapid method for transesterifying cottonseed oil into bio-diesel using a domestic microwave oven (MW) has been developed in the present study. Five parameters were investigated to see their effect on bio-diesel yield output. These were input power, reaction time, oil-to-methanol molar ratio, turntable speed, and fan cooling speed. The respective values used for experimentation were 200 W to 500 W, 4 to 11 minutes, 1:4.5 to 1:12, 10 to 40 rpm, and 800 to 1500 rpm and the volume of the catalyst was kept constant at 1%. The experimental results of microwave study were compared to the traditional magnetic stirrer (MS) approach for the same molar ratio and catalyst amount. The optimum parameters for the transesterification process assisted by the domestic microwave oven were obtained such as methanol to oil molar ratio (1:4.5), potassium hydroxide catalyst concentration (1% (w/w)), reaction time (11 minutes), turntable speed (40 rpm) and cooling fan speed (1500 rpm). The corresponding yield of cottonseed bio-diesel (CBD (MW)) was 99.5 percent. Compared with the contemporary MS approach for the same molar ratio and catalyst number, the yield of CBD (MS) was recorded in 25 minutes as 61.23 percent. It was also found that the turntable speed and cooling fan rpm of the improved microwave oven greatly, influenced the yield of bio-diesel and facilitated better utilization of microwave energy in mixing and avoid overheating of the sample mixture. A drastic reduction in microwave input power consumption was observed as compared to the pragmatic MS approach. The findings of this study have established the utility of energy-efficient, updated domestic microwave oven in the generation of bio-diesel on a small scale.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yongfeng Wei ◽  
Jinyang Huo ◽  
Zhenjun Wang ◽  
Jiangtao Gao

Emulsified asphalt needs to be cured for a certain age after demulsification to produce strength, which seriously affects the traffic opening time. In this work, microwave heating technology was applied for emulsified asphalt repair materials. Steel slag with high microwave activity was adopted to improve the performance of emulsified asphalt repair materials by microwave heating. Effects of steel slag sizes and contents on the heating rate, temperature distribution, and thermal performance of emulsified asphalt repair materials were analyzed by close microwave heating, open microwave heating, and repair simulation tests. Results show that the temperature of emulsified asphalt repair materials presents three different heating stages under microwave irradiation. The “critical point of phase transition” in the three stages is gradually advanced with the increase in steel slag content. The core temperature and maximum temperature of emulsified asphalt repair materials with different steel slag sizes are basically the same; however, the heat distribution of emulsified asphalt repair materials is significantly different. In contrast to conventional asphalt mixture, there exists a smaller temperature difference. The temperature of repairing materials can reach above 80°C. The interface area can form an embedded interface structure. Incorporation of steel slag and adoption of microwave heating are effective to improve the performance of emulsified asphalt repair materials.


2000 ◽  
Vol 15 (10) ◽  
pp. 2176-2181 ◽  
Author(s):  
Oleg Palchik ◽  
Israel Felner ◽  
Gina Kataby ◽  
Aharon Gedanken

Amorphous iron oxide (Fe2O3) was prepared by the pyrolysis of iron pentacarbonyl [Fe(CO)5] in a modified domestic microwave oven in refluxing chlorobenzene as a solvent under air. The reaction time was 20 min. Partially separated particles of iron oxide, 2–3 nm in diameter, were obtained. The other part showed aggregated spheres with a diameter of 25–40 nm. Differential scanning calorimetry measurements showed an amorphous/crystalline phase transition at about 250 °C.


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