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1

Simulation on the dispersion of natural gas and its volume cloud distribution on an offshore fixed platform

Cao Yang, Wang Honghong, Wang Haodong, Gao Yang, Sun Siheng

Archives of Mining Sciences

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2024

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Vol. 68, no. 2

191--209

EN

The formation, migration and volume distribution of gas clouds, which are dominated by natural gas after oil and gas leakage, are the material basis of fire and explosion accidents on offshore platforms. Based on an offshore platform as the background, this paper conducts research on the gas cloud using numerical simulation method, the selection of different wind speeds, leak leakage rate of quality, wind direction and the direction angle, the leakage of gas diffusion behaviour simulation studies and its size distribution. There is a “coupling” effect on the volume value of 5% CH4 cloud between different wind speeds, leakage mass rates, and wind direction and leakage direction. When the wind speed is 13 m/s, the leakage mass velocity is 8 kg/s, and the included angle between wind direction and leakage direction is 180°, the “coupling” effect on the volume value of 5% CH4 cloud increases significantly. The above research results can provide a reference for the reasonable division of process risk area, firewall design and quantitative risk assessment of fire and explosion of an offshore platform.

2

Separation and purification of light rare earth elements from chloride media using P204 and Cyanex272 in sulfonated kerosene under non-saponification conditions

Fan Peiqiang, Zhang Wenjie, Tong Xiong, Xie Xian, Xie Ruiqi, Song Qiang, Du Yunpeng, Cao Yang

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 6

art. no. 172444

EN

The extraction of light rare earths (Pr and Nd) from chloride medium was investigated using a mixture of di(2-ethylhexyl) phosphoric acid (P204) and bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex272) in sulfonated kerosene. The P204+Cyanex272 system exerted a synergistic effect on the separation of light rare earths, and the separation coefficient was higher than when P204 and Cyanex272 were used as extractants alone. The separation coefficient of Pr and Nd in the extraction system reached 1.75 when the pH of the aqueous phase material solution was approximately 2.5, and 1.5 mol/L hydrochloric acid as a stripping agent effectively eluted the rare earth ions in the loaded organic phase. Combining the slope method, infrared spectroscopy, and nuclear magnetic resonance spectroscopy, we explored the mechanism of the extracted Nd and Pr into the organic phase complex, and finally entered the organic phase with Re(HA2)2B. The P-O-H bond and P=O bond in the extractant P204 and Cyanex272 formed a coordination bond with Re3+. Therefore, this extraction method also provides a reference for a more environmentally friendly and efficient procedure for separation and purification of light rare earth elements Pr and Nd.

3

Synergistic emulsification of polyetheramine/nanofluid system as a novel viscosity reducer of acidic crude oil

Cao Yang, Guo Yanlin, Wu Tao, Sun Dejun

Materials Science Poland

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2023

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Vol. 41, No. 4

107--119

EN

Oil is a critical raw material for energy and industry, the depletion of conventional oil reserves necessitates efficient extraction and production of unconventional resources like acidic crude oil. However, its high viscosity poses significant challenges for transportation and processing. To address these challenges, this study developed a novel emulsion viscosity reducer. We designed a nanofluid based on a synergistic polyetheramine/nanofluid system consisting of alkyl ethoxy polyglycosides (AEG) as a green surfactant, SiO2 nanoparticles, and an organic alkali polyetheramine. The mixture was evaluated for its viscosity reduction and emulsification performance with acidic crude oi obtained from Qinghe oil production plant in Shengli Oilfield. The results showed that the optimized viscosity reducer achieved a remarkable reduction rate of 98.1% at 50°C in crude oil viscosity from 6862 mPa·s to 129 mPa·s. This demonstrated the reducer effectively transformed acidic crude oil into a low viscosity oil-in-water (O/W) emulsion with high stability. Furthermore, the core imbibition simulation tests demonstrated that the viscosity reducer could improve the recovery of acidic crude oil from 29.6% to 49.4%, indicating the potential application of the optimized viscosity reducer in the exploitation of acidic crude oil. In conclusion, this study developed a novel emulsion viscosity reducer, which can reduce the viscosity and improve recovery of acidic crude oil by emulsifying into O/W emulsion. The optimized formula has potential for practical application in the exploitation of acidic crude oil.

4

Automated detection of multi-class urinary sediment particles: An accurate deep learning approach

Lyu He, Xu Fanxin, Jin Tao, Zheng Siyi, Zhou Chenchen, Cao Yang, Luo Bin, Huang Qinzhen, Xiang Wei, Li Dong

Biocybernetics and Biomedical Engineering

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2023

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Vol. 43, no. 4

672--683

EN

Urine microscopy is an essential diagnostic tool for kidney and urinary tract diseases, with automated analysis of urinary sediment particles improving diagnostic efficiency. However, some urinary sediment particles remain challenging to identify due to individual variations, blurred boundaries, and unbalanced samples. This research aims to mitigate the adverse effects of urine sediment particles while improving multi-class detection performance. We proposed an innovative model based on improved YOLOX for detecting urine sediment particles (YUS-Net). The combination of urine sediment data augmentation and overall pre-trained weights enhances model optimization potential. Furthermore, we incorporate the attention module into the critical feature transfer path and employ a novel loss function, Varifocal loss, to facilitate the extraction of discriminative features, which assists in the identification of densely distributed small objects. Based on the USE dataset, YUS-Net achieves the mean Average Precision (mAP) of 96.07%, 99.35% average precision, and 96.77% average recall, with a latency of 26.13 ms per image. The specific metrics for each category are as follows: cast: 99.66% AP; cryst: 100% AP; epith: 92.31% AP; epithn: 100% AP; eryth: 92.31% AP; leuko: 99.90% AP; mycete: 99.96% AP. With a practical network structure, YUS-Net achieved efficient, accurate, end-to-end urinary sediment particle detection. The model takes native high-resolution images as input without additional steps. Finally, a data augmentation strategy appropriate for the urinary microscopic image domain is established, which provides a novel approach for applying other methods in urine microscopic images.

5

Numerical simulation on consequences of generator fire accident on offshore platform – a case study

Cao Yang, Honghong Wang, Haodong Wang

Archives of Mining Sciences

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2023

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Vol. 68, no. 2

267--283

EN

The high temperature and thermal radiation caused by generator fire accidents on the offshore platform lead to the destruction of equipment and facilities and threaten the structural safety of the offshore platform. Based on the background of a crude oil generator fire accident on an offshore platform, KFX software was used to conduct a numerical simulation of the fire process and explore the spatial-temporal variation characteristics of smoke, temperature and heat radiation within the scope of the fire room. The influence ranges of 12.5 kW/m2, 25 kW/m2 and 35 kW/m2 were obtained according to the thermal radiation criterion. Researchers examined the temperature variation and heat flow at the room’s ceiling and floor near the primary steel support. The results show that: 1) The surface temperatures of partial steel supports exceed 550°C, and the heat flux of partial steel supports exceeds 37.5 kW/m2. 2) In the ignition position, the maximum temperature at the ceiling reaches 2299°C when t = 24 s, and the maximum temperature at the flooring reaches 701°C when t = 79 s. The heat radiation flux at the ceiling and flooring both exceeds 25 kW/m2. The maximum temperature of partial crude oil generators can reach 1299°C. 3) The heat radiation flux of partial generators can reach 105 kW/m2, and the heat radiation flux at the adjacent point of partial generators never exceeds 20 kW/m2. The above research results can provide a reference for checking the response time of flame detectors and the strength of the supporting structure.

6

A first-principle study of the effect of Fe/Al impurity defects on the surface wettability of dolomite

Chen Hong, Ao Xianquan, Cao Yang, Li Cuiqin, Jiang Chunyan

Physicochemical Problems of Mineral Processing

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2022

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Vol. 58, iss. 4

art. no. 150702

EN

The presence of Fe and Al atoms in large quantities in phosphate ores can significantly affect the surface properties of the minerals during flotation. In this study, the effects of Fe/Al impurities on the adsorption of H2O molecules on dolomite, including the density of states (DOS), Mulliken bond group values, and charge groups, were investigated and the adsorption energy was analyzed using density functional theory. The results show that the adsorption of H2O molecules on perfect and Fe/Al-substituted dolomites is weak chemisorption, and the Fe and Al impurities weaken and enhance the adsorption capacity of H2O molecules, respectively. Therefore, the hydrophilicity of the dolomite surface increases in the following order: Fe-substituted dolomite < perfect dolomite < Al-substituted dolomite. The Mulliken charge and bond group analysis shows that the adsorption of H2O molecules on dolomite is primarily through the interaction between Ow and Ca atoms, where the d orbitals of Ca atoms provide charges for Ow atoms to form ionic bonds, which related to the poor electronegativity of Ca atoms and their weak valence electron binding ability. The DOS analysis shows that, during the adsorption of H2O molecules on dolomite, Mg and Al atoms have less influence on the dolomite surface, whereas Fe and Ca atoms undergo competitive adsorption, which inhibits the interaction between Ca atoms and H2O molecules on the dolomite surface.

7

New event based H∞ state estimation for discrete-time recurrent delayed semi-markov jump neural networks via a novel summation inequality

Cao Yang, Maheswari K., Dharan S., Sivaranjani K.

Journal of Artificial Intelligence and Soft Computing Research

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2022

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Vol. 12, No. 3

207--227

EN

This paper investigates the event-based state estimation for discrete-time recurrent delayed semi-Markovian neural networks. An event-triggering protocol is introduced to find measurement output with a specific triggering condition so as to lower the burden of the data communication. A novel summation inequality is established for the existence of asymptotic stability of the estimation error system. The problem addressed here is to construct an H∞ state estimation that guarantees the asymptotic stability with the novel summation inequality, characterized by event-triggered transmission. By the Lyapunov functional technique, the explicit expressions for the gain are established. Finally, two examples are exploited numerically to illustrate the usefulness of the new methodology.

8

Stability and dissipativity analysis for neutral type stochastic Markovian jump static neural networks with time delays

Cao Yang, Samidurai R., Sriraman R.

Journal of Artificial Intelligence and Soft Computing Research

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2019

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Vol. 9, No. 3

189--204

EN

This paper studies the global asymptotic stability and dissipativity problem for a class of neutral type stochastic Markovian Jump Static Neural Networks (NTSMJSNNs) with time-varying delays. By constructing an appropriate Lyapunov-Krasovskii Functional (LKF) with some augmented delay-dependent terms and by using integral inequalities to bound the derivative of the integral terms, some new sufficient conditions have been obtained, which ensure that the global asymptotic stability in the mean square. The results obtained in this paper are expressed in terms of Strict Linear Matrix Inequalities (LMIs), whose feasible solutions can be verified by effective MATLAB LMI control toolbox. Finally, examples and simulations are given to show the validity and advantages of the proposed results.