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Zulqarnain,전동혁,김수현,유지호 한국에너지기후변화학회 2023 에너지기후변화학회지 Vol.18 No.2
Highly concentrated volatile organic compounds (VOCs) as a precursor of PM2.5 are emitted from car painting booths, laundry facilities, printing machines, and refinery industries in Korea. They have high volatility, strong resistance to degradation, and release a significant amount of heat into the atmosphere. Exposure to them can also cause serious damage to human health. Therefore, recycling is necessary instead of discharge to the environment. Currently, hydrogen (H2), as a carbon-neutral energy alternative to fossil fuels, is synthesized from the steam reforming of highly concentrated toluene. However, catalyst deactivation caused by coke deposition is one of the main challenges in steam reforming reactions. Temperature and steam-to-carbon (S/C) ratio are the crucial reaction parameters significantly contribute to the deposition of coke on the surface of the catalyst. Highly concentrated toluene was steam-reformed for 24 hours to study the coking behavior of Ni/Al2O3 at T = 400 - 600 °C, (S/C) = 3 - 12, and gas-hourly-space velocity (GHSV) = 15,000 hr-1 in this study. The maximum rate of carbon deposition of 180.96 mgc/gcat and H2 yield of 91% is observed at T = 550 °C, S/C = 6 in the presence of Ni/Alumina catalyst. At 400 °C and 450 °C with a S/C ratio of 6, the formation of amorphous coke was observed, which deactivated the activity of the catalyst. Filamentous coke was dominant at temperatures between 500 °C and 600 °C and with an S/C ratio of 9 to 12, but it had no significant effect on catalyst stability.
Syed Zulqarnain Haider,Hafeez Anwar,Sehrish Manzoor,Ahmad G. Ismail,Mingqing Wang 한국물리학회 2020 Current Applied Physics Vol.20 No.9
Inverted perovskite solar cells (p-i-n PSCs) have been fascinated due to rapid progress of performance in recent years. PEDOT:PSS is commonly used hole transport material (HTM) in p-i-n PSCs having hygroscopic and acidic nature that leads towards poor performance of device. Therefore, it is necessary to replace PEDOT:PSS with stable HTM. In this paper, theoretical study is carried out to investigate physical parameters that can affect the performance of p-i-n PSCs with copper iodide (CuI) as HTM. These parameters include the effect of doping density of electron transport material (ETM), absorber and HTM as well as defect density and thickness of absorber on the performance of p-i-n PSCs. Hole mobility and thickness of HTM are also investigated. It is found that performance of p-i-n PSCs is strongly dependent on defect density and thickness of absorber. Upon final optimization, device attains PCE of more than 21% which is encouraging.
Shahid Ghazi,Perveiz Khalid,Tahir Aziz,Zulqarnain Sajid,Tanzila Hanif 한국지질과학협의회 2016 Geosciences Journal Vol.20 No.1
The Khewra Sandstone is widely distributed throughout the Potwar Basin of Pakistan. Its reservoir aspects are evaluated by the interpretation of well log data recorded from Kal-01 and Kal- 02 wells in the Kal Oil Field, eastern Potwar Basin. The encountered thickness of the Khewra Sandstone in Kal-01and Kal-02 varies from 60 m to 120 m. On the basis of lithological interpretation from wireline logs the formation is divided into four facies: 1) shale interbedded with minor siltstone and sandstone, 2) sandstone with alternating siltstone and claystone/shale, 3) claystone /shale, siltstone interbedded with fine to medium grained sandstone and 4) fine to coarse grained sandstone with channels. The log derived average porosity in Khewra Sandstone is about 14–22% with permeability ranges from 20–58 mD. Thus, it possesses a large storage capacity for moveable hydrocarbons in Kal Oil Field. Facies 4, in the upper part of the Khewra Sandstone, is interpreted as potential reservoir interval with hydrocarbon saturation ranges from 77–79%. Based on isopach map, the formation is interpreted to be well developed in NE-SW which gradually thins basinward to the west and northwest direction. The play fairway analysis suggested very high chances of hydrocarbon entrapment is in the Kal Oil Field.
Auto-Encoder Variants for Solving Handwritten Digits Classification Problem
Muhammad Aamir,Nazri Mohd Nawi,Hairulnizam Bin Mahdin,Rashid Naseem,Muhammad Zulqarnain 한국지능시스템학회 2020 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.20 No.1
Auto-encoders (AEs) have been proposed for solving many problems in the domain of machine learning and deep learning since the last few decades. Due to their satisfactory performance, their multiple variations have also recently appeared. First, we introduce the conventional AE model and its different variant for learning abstract features from data by using a contrastive divergence algorithm. Second, we present the major differences among the following three popular AE variants: sparse AE (SAE), denoising AE (DAE), and contractive AE (CAE). Third, the main contribution of this study is performing the comparative study of the aforementioned three AE variants on the basis of their mathematical modeling and experiments. All the variants of the standard AE are evaluated on the basis of the MNIST benchmark handwritten digit dataset for classification problem. The observed output reveals the benefit of using the AE model and its variants. From the experiments, it is concluded that CAE achieved better classification accuracy than those of SAE and DAE.
Regeneration of commercial SCR catalyst deactivated by arsenic poisoning in coal-fired power plants
Qiang Lu,Zulfiqar Ali,Hao Tang,Tahir Iqbal,Zulqarnain Arain,Min-shu Cui,Ding-jia Liu,Wen-yan Li,Yong-ping Yang 한국화학공학회 2019 Korean Journal of Chemical Engineering Vol.36 No.3
Arsenic species, which are inevitable components in flue gas from the coal combustion process, will result in severe deactivation of selective catalytic reduction (SCR) catalysts. In this paper, a novel method is proposed to regenerate the arsenic-poisoned commercial V2O5-MoO3/TiO2 catalyst collected from coal-fired power plants, including ammonia washing, H2 reduction, and air calcination. Activity tests indicated that the proposed method could recover the catalyst activity more than 96% of the fresh catalyst. Furthermore, detailed characterizations results indicated that this regeneration method could not only effectively remove the arsenic species, but also recover the active constituents of the catalysts to a considerable level. The proposed method offers a feasible strategy for the regeneration of poisoned commercial SCR catalysts and can effectively reduce the total denitrification cost for coal-fired power plants.