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Preparation of Waste Cooking Oil-based Biodiesel Using Microwave Energy: Optimization by Box-Behnken Design Model (마이크로웨이브 에너지를 이용한 폐식용유 원료 바이오디젤의 제조: Box-Behnken 설계를 이용한 최적화)

  • Lee, Seung Bum;Jang, Hyun Sik;Yoo, Bong-Ho
    • Applied Chemistry for Engineering
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    • v.29 no.6
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    • pp.746-752
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    • 2018

  • In this study, an optimized process for the waste cooking oil based biodiesel production using microwave energy was designed by using Box-Behnken design model. The process variables were chosen as a mole ratio of the methanol to oil, microwave power, and reaction time. Fatty acid methyl ester (FAME) content was then measured. Through the results of basic experiments, the range of optimum operation variables for the Box-Behnken design model, such as the methanol/oil mole ratio and reaction time, were set as between 8 to 10 and between 4 to 6 min, respectively. Ranges of the microwave power were set as from 8 to 12 W/g for 1.30 mg of KOH/g, acid value, while from 10 to 14 W/g for 2.00 mg of KOH/g, acid value. The optimum methanol/oil mole ratio, microwave power, and reaction time were reduced to 7.58, 10.26 W/g, and 5.1 min, respectively, for 1.30 mg KOH/g of acid value. Also, the optimum methanol/oil mole ratio, microwave power, and reaction time were 7.78, 12.18 W/g, and 5.1 min, respectively, for 2.00 mg KOH/g of acid value. Predicted FAME contents were 98.4% and 96.3%, with error rates of less than 0.3%. Therefore, when the optimized process of biodiesel production using microwave energy was applied to the Box-Behnken design model, the low error rate could be obtained.

  • https://doi.org/10.14478/ace.2018.1083 인용 PDF KSCI HTML

The Coexistence of OFDM-Based Systems Beyond 3G with Fixed Service Microwave Systems

  • Jo Han-Shin;Yoon Hyun-Goo;Lim Jae-Woo;Chung Woo-Ghee;Yook Jong-Gwan;Park Han-Kyu
    • Journal of Communications and Networks
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    • v.8 no.2
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    • pp.187-193
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    • 2006

  • In this paper, we study the coexistence of orthogonal frequency division multiplexing (OFDM)-based systems beyond 3G (B3G) and point-to-point (P-P) fixed service (FS) microwave systems. The advanced general analytical model derived via a power spectral density (PSD) analysis proposed in this paper has two advantages in comparison with the conventional minimum coupling loss (MCL) method. First, the interfering signal power that appears in the band of a victim system can be easily assessed without a spectrum emission mask. Second, when transmit power is not allocated to some subcarriers overlapping the band of the victim system in order to mitigate B3G OFDM-based systems interference with other systems, the general analytical model can successfully assess the interference from the B3G systems into FS systems, whereas the MCL method incorporating the spectrum emission mask cannot be applied in the presence of the same interference condition. The proposed model can be derived in a closed form and is simply implemented with the help of simulation, and thus the solution can be obtained in significantly reduced time. Through application of the proposed model, coexistence results are analyzed in a co-channel and adjacent channel with respect to guard band and minimum separation distance.

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