scholarly journals Profil Suhu dan Kadar Air Kayu dalam Pengeringan Oven Pemanas dan Gelombang Mikro (Temperature and Moisture Content Profiles of Woods in Heating and Microwave Ovens Drying)

2021 ◽  
Vol 17 (2) ◽  
pp. 160-171
Author(s):  
Trisna Priadi ◽  
Gunes T W Giyarto
Keyword(s):  
Moisture Content ◽  
Microwave Oven ◽  
Microwave Drying ◽  
Temperature Profiles ◽  
Moisture Profile ◽  
Moisture Movement ◽  
Oven Drying ◽  
Pinus Oocarpa ◽  
Moisture Profiles ◽  
Made In

This research aimed to evaluate the profile of temperature and moisture content in Pinus oocarpa wood being dried with heating oven and microwave oven.  The size of samples were (25x70x120) mm3.  The temperature profiles in heating oven and microwave oven drying were taken every 10 minutes and 0.5 minutes, respectively. The moisture profiles in heating oven and microwave oven drying were made in every 24 hours and 10 minutes, respectively.  The heating oven was set at 60 °C, while microwave oven was set for 2 minutes intermittently with 5 minutes break.  In microwave drying, the temperature inside the boards increased faster and higher compared to that in the heating oven, which resulted in a faster moisture movement to the board’s surface.  The drying rate of pine increased 48-72 times in microwave compared to that in heating oven.  The moisture content in the centre of boards being dried in heating oven was much higher than that of in the outer parts.  On the other hand, the moisture profile in the woods being dried in microwave oven distributed more evenly.

Research on Measurement of Grass’s Moisture Content with Microwave Oven Method

2014 ◽  
Vol 707 ◽  
pp. 417-421
Author(s):  
Yan Feng ◽  
Qing Qing Shen ◽  
Li Li Chen ◽  
Shu Ling Luo ◽  
Guang Biao Jiang ◽  
...  
Keyword(s):  
Moisture Content ◽  
Microwave Oven ◽  
Drying Method ◽  
Oven Method ◽  
Important Indicator ◽  
Oven Drying ◽  
Viable Method

In the process of working, storage, finished fodder acceptance and the preservation process of grass materials, the moisture content of forage is a very important indicator. The blast oven drying method has been generally adopted in the measurement of moisture content. The related experiment showed that the microwave oven method for grass moisture content measuring improved 200-400 times in the efficiency compared with blast oven drying method. The microwave oven method was accurate and easy operating. So, we can conclude that microwave oven method is a viable method for measuring the moisture content.

scholarly journals Studies of the Combined Modes of Microwave Grain Drying

2018 ◽  
Vol 12 (6) ◽  
pp. 25-30
Author(s):  
Sergey A. Pavlov ◽  
Igor A. Pekhalsky ◽  
Nikolay G. Nikolay G. Kynev
Keyword(s):  
Moisture Content ◽  
Microwave Pulse ◽  
Raw Materials ◽  
Removal Rate ◽  
Pause Duration ◽  
Microwave Drying ◽  
Flow Density ◽  
Moisture Removal ◽  
Moisture Movement ◽  
Vegetable Raw Materials

Abstract. To ensure the high quality of the materials being dried, one of the most promising ways to dehydrate vegetable raw materials is drying under the action of electromagnetic radiation (microwave drying). Microwave drying is widely used in various industries, in particular, in the food and woodworking industries. (Research purpose) Calculation of the microwave pulse and pause duration; their experimental determination, as well as the determination of the moisture removal rate at the pulse moment and the depth of pulse penetration into the layer. (Materials and methods) When drying in a microwave field, the gradient of moisture content in the material prevents the moisture movement towards the surface, internal cracks can be formed as well. Therefore, the combined methods of drying can yield the best results. The pulse duration has been calculated by the permissible increment of the grain temperature, the pause duration has been determined by assuming that during the pulse, moisture from the caryopsis kernel is pushed out and cooled under isothermal conditions by an air flow. (Results and discussion) It has been confirmed that at a microwave pulse energy duration of 4, 6, and 10 s, the speed of blow-off and blowdown of the layer with external air was 0.5 m per second. When grain is cooled by natural convection, the pulse time is 10 s, the pause time is 1, 2, 3, and 5 min. For the blow-off mode, the pulse exposure time was 6 and 10 s, that of blow-off - 0.5, 1.0, and 1.5 minutes. The maximum duration of the microwave pulse was determined by the flow density of allowable grain heating and the fraction of heat required for the evaporation of moisture when heated to 20-25 degrees. (Conclusions) The pause duration is determined by the grain cooling time to the temperature preceding the pulse. It has been experimentally established that the calculated values of the pulse and pause duration with an accuracy of 15 percent for grain with a moisture content of 20-24 percent at a microwave flow density of 0.7 kilowatts per square meter, at a depth of the microwave energy penetration into the grain by 70 percent, do not exceed 20-22 mm, and the moisture removal rate is 0.1-0.15 percent.

scholarly journals Effects of microwave power and slice thickness on fiber and ash contents of dried sweet potato (Ipomoea batata)

2020 ◽  
Vol 39 (3) ◽  
Author(s):  
C.O. Nwajinka ◽  
E.O. Okonjo ◽  
D.O. Amaefule ◽  
D.C. Okpala
Keyword(s):  
Moisture Content ◽  
Response Surface ◽  
Sweet Potato ◽  
Microwave Power ◽  
Initial Moisture Content ◽  
Microwave Oven ◽  
Microwave Drying ◽  
Average Moisture Content ◽  
Slice Thickness ◽  
Potato Slices

Investigation of microwave drying of sweet potato slices was conducted at microwave oven power settings of 90, 100, 120 Watts and slice thicknesses of 3mm, 4mm and 6mm using Fourier models and response surface methods. The slice samples dried from initial moisture content of 70.71𝒈𝒘𝒂𝒕𝒆𝒓/𝒈𝒅𝒓𝒚 𝒎𝒂𝒕𝒕𝒆𝒓 to 12.7𝒈𝒘𝒂𝒕𝒆𝒓/𝒈𝒅𝒓𝒚 𝒎𝒂𝒕𝒕𝒆𝒓 final (equilibrium) moisture content in the microwave oven. Fourier models adequately fitted the drying data with the following values of the fit parameters: MBE= 0.00002943 to 0.000645, R² = 0.9987 to 1, RMSE = 0.00384 to 0.01692. Effective moisture diffusion coefficient (𝑫𝒆) of the samples ranged from 𝟏.𝟎𝟖𝟐𝟐 × 𝟏𝟎−𝟑m2/s to 𝟖.𝟑𝟖𝟏𝟐 × 𝟏𝟎−𝟑 m2/s. Analysis of Variance (ANOVA) was used to analyze the effect of drying conditions on the samples parameters at 95% ( p<0.05). The results showed that slice thickness and microwave power have significant effects on the ash and fiber contents of the dried potato samples. At the microwave power of 90 W and slice thickness of 4 mm the values of Fiber and Ash retained in the dried sweet potato samples were optimal at 4.30% and 2.50% respectively, after drying for 390 minutes to an average moisture content of 14.2 gH2O/gdm. Optimized equations for predicting the percent ash and fiber contents at combined factors of microwave power and slice thickness were developed using Response Surface Methodology (RSM) at 95% confidence bound. The coefficients of determination (R2) for the models are 0.7333 and 0.9655 for fiber and ash respectively. These are indications that the models can be used to predict the two food components of microwave dried potato slices. Keywords: RSM, Fourier Model, Microwave, Sweet Potato, Ash, Fiber

scholarly journals Potential of microwave drying technology for increase drying rate and physical quality of kaffir lime (Citrus hystrix DC) leaves

2021 ◽  
Vol 924 (1) ◽  
pp. 012045
Author(s):  
F Su’aidah ◽  
I Taruna
Keyword(s):  
Moisture Content ◽  
Power Level ◽  
Preference Test ◽  
Color Difference ◽  
Microwave Drying ◽  
Drying Rate ◽  
Physical Quality ◽  
Oven Drying ◽  
Drying Rates

Abstract The effects of microwave power on microwave drying rates and the physical quality of kaffir lime leaves were studied. Three power levels were used in this study, high (723 watts), medium (537 watts), and low (420 watts). The moisture content, drying rate, color (L, a, b), and organoleptic parameters of each power level will be compared with the oven drying method (60°C). The result shows that the final moisture content of the high, medium, and low power of microwave drying are 6.06, 4.26%, and 6.16%db respectively, which is lower than oven drying, 16.62%db. Besides, the drying rate of microwave drying is 26.39-48.71%db/minute, higher than oven drying 0.32%db/minute. Dried kaffir lime leaves with medium level power (537 watt) has the lowest color difference (ΔE = 1.0 ± 0.29) compared to fresh leaves. While, the color and aromatic preference test dried kaffir lime leaves by microwave drying was preferable than oven drying.

Microwave Oven Drying in the Gravimetric Phosphorus Method

1981 ◽  
Vol 64 (6) ◽  
pp. 1319-1321
Author(s):  
James R Melton ◽  
William L Hoover
Keyword(s):  
Microwave Oven ◽  
Microwave Drying ◽  
Distinct Advantage ◽  
Oven Drying ◽  
Yellow Precipitate ◽  
Conventional Drying

Abstract The gravimetric quinolinium molybdophosphate method for determining P2O5 in fertilizers, AOAC 2.026–2.028, has been modified to permit the precipitate to be dried in a microwave oven rather than a conventional drying oven. After the yellow quinolinium molybdophosphate precipitate is formed, cleaned up, and washed, it is placed in a microwave oven at 600 watts until dry. The quantity of precipitate remaining after microwave drying was equal to that obtained by drying according to AOAC 2.028 for several fertilizer samples. A distinct advantage of the described method is that the yellow precipitate will not char with reasonably excessive drying. Also, much less energy is expended with the microwave oven than with the drying oven.

scholarly journals The Effect of Microwave Oven Drying on the Compressive Strength of Type III and IV Dental Stones at Different Time Intervals

2018 ◽  
Vol 12 (1) ◽  
pp. 494-500
Author(s):  
Suha Fadhil Dulaimi ◽  
Sabiha Mehdi Kanaan
Keyword(s):  
Compressive Strength ◽  
Microwave Oven ◽  
Microwave Drying ◽  
Time Interval ◽  
Time Intervals ◽  
Mean Values ◽  
Oven Drying ◽  
Type Iii ◽  
Type Iv ◽  
Significant Difference

Background:Dental stone cast needs 24 to 48 hours to evaporate excess water and acquire enough strength for manipulation. The microwave oven is used to save time by drying and disinfecting stone casts.Objectives:The aim of the present study is to evaluate the effect of microwave oven drying on the compressive strength of Type III and Type IV dental stone in three time intervals-3 hours, 5 hours and 24 hours after pouring.Methods:The study involved 120 samples: 60 samples for each type of dental stone. Thirty samples were subjected to air drying at 3, 5 and 24 hours) and 30 samples were dried in the microwave oven at 2450 MHZ -900 W for 150 seconds (at 3, 5 and 24 hours). The samples were tested by unconfined compression machine, with a 2000 kg proving ring at cross-head speed of 1 mm/min.Results:For the Type III dental stone drying at 3 hours, microwave radiation causes a significant increase in compressive strength and shows the highest score (mean 125 kg/cm); however, at 5 hours no significant difference was observed. However, at the 24 hour time interval, microwave drying causes significant reduction in the mean (100 kg/cm)p<0.01 .For the Type IV dental stone testing at all-time intervals (3,5, 24 hours), a significant reduction (p<0.05) in mean values was shown(80,85,87 respectively).Conclusion:Microwave oven drying increased the compressive strength of Type III dental stone at the 3 hour time interval from pouring, while microwave drying at the 5 hour interval had no significant effect; and at 24 hour the compressive strength of the dental stone was reduced. For the Type IV dental stone microwave drying had a detrimental effect on compressive strength at all-time intervals.

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