https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/203 2026-07-03T13:56:21Z 2026-07-03T13:56:21Z Oh, S. Byun, Joong moo https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/169983 2022-07-19T04:43:54Z

Title: Bayesian Uncertainty Estimation for Deep Learning Inversion of Electromagnetic Data Authors: Oh, S.; Byun, Joong moo Abstract: With the recent progress in deep learning (DL), DL inversion, which reconstructs subsurface physical properties from geophysical data using DL techniques, has been widely applied. For decision-making and risk management related to the application of DL inversion, assessing the reliability of a prediction is essential, and such assessment can be achieved through uncertainty estimation. However, most geophysical studies have focused on deterministic prediction that does not provide uncertainty estimates. In this letter, a practical uncertainty estimation method based on the Bayesian framework is introduced for DL inversion of electromagnetic data. More specifically, iterative estimation by a convolutional neural network with dropout provides epistemic and aleatoric uncertainties as well as a resistivity model. Using numerical tests, we observed that aleatoric uncertainty indicates the nonuniqueness of the inverse problem, showing which parts of the resistivity model are less sensitive to the data. In addition, we proposed an empirical criterion for determining whether new data are similar to training data using estimated epistemic and aleatoric uncertainties. Based on this criterion, out-of-distribution data were identified; these data showed larger data misfit, indicating that the predictions would be unreliable. The applicability of uncertainty estimation and the empirical criterion derived from uncertainties were demonstrated using field data. Bayesian uncertainty estimation and the criterion established here may help to achieve more reliable prediction via DL inversion.

Faisal, Shah Salama, El-Sayed Hassan, Sedky H. A. Jeon, Byong Hun Li, Xiangkai https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/169985 2022-07-19T04:44:07Z

Title: Biomethane enhancement via plastic carriers in anaerobic co-digestion of agricultural wastes Authors: Faisal, Shah; Salama, El-Sayed; Hassan, Sedky H. A.; Jeon, Byong Hun; Li, Xiangkai Abstract: Two types of plastic carriers low-density polyethylene (LDPET) and high-density polyethylene (HDPET) were used as a support material for biofilm formation during anaerobic co-digestion of agricultural wastes. LDPET and HDPET were added separately to different reactors containing binary substrates: corn straw and cauliflower leaves (G 1), corn straw and cow dung (G 2), while ternary substrates corn straw, cauliflower leaves, and cow dung were used in G 3. Reactors containing either HDPET or LDPET carriers supported the enhancement of biogas and biomethane. Maximum daily biomethane (333.43 and 368.35 mL/day) was achieved after HDPET addition to G1 and G2 at day 10 and 12, respectively. The accumulative biomethane were significantly enhanced (p < 0.05) by 17.14% and 23.52%, compared with reactors having LDPET carriers 11.89% and 5.53%, respectively. HDPET addition to ternary substrates (G 3) resulted in highest biomethane production (31.61%) and total solids (31.70%) and volatile solid (61.63%) removal. The major short-chain fatty acids (SCFAs) detected in all groups were acetic acid (4-5 g/L) and propionic acid (2-3 g/L), and their conversion to biomethane was the highest with HDPET. Scanning electron microscopy (SEM) analysis of the supporting materials showed that the plastic carriers support the biofilm formation especially in the case of HDPET. This study demonstrated that addition of cost-effective plastic carrier (HDPET) to anaerobic digestion system supported the formation of biofilm, leading to significantly increase in substrate utilization and biomethane production.

Yoon, Joo-Hyeong Kim, Jong-Su Kwon, Eilhann E. Jeong, Soo-Hwa https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/217633 2026-06-26T05:30:42Z 2027-01-01T00:00:00Z

Title: Hydrogen-rich producer gas from air- and steam-blown co-gasification of waste polypropylene pyrolysis oil and cashew nut shell in a two-stage downdraft gasifier Authors: Yoon, Joo-Hyeong; Kim, Jong-Su; Kwon, Eilhann E.; Jeong, Soo-Hwa Abstract: The co-gasification of waste polypropylene pyrolysis oil (WPPO) and cashew nut shell (CNS) was investigated in a two-stage downdraft gasifier to produce hydrogen-rich, low-tar gas. Experiments were conducted under air (ER = 0.3) and steam (S/C = 2.5) conditions, with selected runs incorporating activated carbon (AC) in the secondary reactor. Steam gasification achieved a maximum hydrogen concentration of 77.9 vol%. The WPPO/CNS mixing ratio affected performance, with the 1:1 blend increasing CGE from 70.3 to 89.7% to 108.9% and CCE from 68.2 to 71.5% to 83.9%, along with enhanced gas yield. The use of AC reduced gas-phase tar, and a downstream dried AC impinger further decreased tar concentration to 0.45 mg/Nm3. In contrast, the composition of condensed tar showed a shift toward heavier species during steam gasification. GC–MS analysis at a WPPO/CNS ratio of 1:1 indicated that steam gasification promoted the formation of heavier PAHs due to enhanced thermal cracking and subsequent polymerization of aromatic intermediates.

2027-01-01T00:00:00Z Paul, Sourab Nayak, Jayato Khare, Divya Islam, Md Monjurul Kumar, Ramesh Jeon, Byong-Hun https://scholarworks.bwise.kr/hanyang/handle/2021.sw.hanyang/213334 2026-06-17T05:30:32Z 2026-12-01T00:00:00Z

Title: Scale-up of rhamnolipid biosynthesis via agro-waste valorization: Techno-economic assessment with cradle-to-gate life cycle analysis Authors: Paul, Sourab; Nayak, Jayato; Khare, Divya; Islam, Md Monjurul; Kumar, Ramesh; Jeon, Byong-Hun Abstract: This work explores a waste valorization approach for producing rhamnolipids using two abundant residues: crude cellulose (40%) derived from sawdust and crude glycerol (45%) from waste cooking oil. Rigorous experimental studies showed that mono-substrate fermentations resulted in lower product yields, prompting the use of dual-substrate (3% w/v cellulose + 3% w/v glycerol) fermentations by Pseudomonas aeruginosa 2297. Dual-substrate fermentations produced the highest titer of 6021 ± 235.25 mg/L of rhamnolipids, compared to the respective product concentrations of 3711.37 ± 34.3 mg/L and 1634.90 ± 131.49 mg/L obtained with crude glycerol (4% w/v) and crude cellulose (4% w/v) as sole carbon sources, respectively. Produced rhamnolipid showed about 40.73 ± 2.09% oil recovery using a sand-packed column. Techno-economic evaluation established a minimum selling price of USD 1.57/g at a null net present value, indicating potential economic competitiveness. A cradle-to-gate life cycle assessment showed a carbon footprint of 1.73 kg CO2-eq/g of rhamnolipid, which is better than that reported in recent literature. Further optimization of utility consumption parameters can reduce the carbon footprint and other environmental impacts, thereby providing a basis for appropriate policy recommendations.

2026-12-01T00:00:00Z