Guest enclathration and structural transition in CO2 + N2 + methylcyclopentane hydrates and their significance for CO2 capture and sequestration

The phase equilibria, structural transition, gas uptake, and composition of CO2 + N-2 + methylcyclopentane (MCP) hydrates were investigated for their potential applications in CO2 capture and sequestration. Thermodynamic stability conditions indicated that flue gas could form sH hydrates in the presence of MCP at a reduced pressure and an elevated temperature. Powder X-ray diffraction (PXRD) and Raman analyses revealed that the structural transition of CO2 + N-2 + MCP hydrates occurs from sH to sI with increasing CO2 concentration and that both sH and sI coexist at a boundary composition of CO2 (20%) +N-2 (80%). In situ Raman spectroscopy provided direct evidence of the enclathration of CO2 and MCP in cages of sH hydrates under highly N-2-rich conditions. The sH CO2 + N-2 + MCP hydrates demonstrated slightly lower gas uptakes and CO2 selectivity in the hydrate phase than corresponding sI CO2 + N-2 hydrates, despite their thermodynamic advantages. The overall experimental results obtained in this study can help create a better understanding of guest enclathration and structural transition in sH hydrates and thus provide new insights into sH hydrate-based CO2 capture and sequestration using flue gas

Improved Vehicle Detection Algorithm in Heavy Traffic for Intelligent Vehicle

Despite significant progress in vehicle detection over the last few decades, vehicle detection performance in heavy traffic is still inadequate. In this paper, we propose a new algorithm for vehicle detection in heavy traffic to improve detection performance. It uses two proposed segmentation methods, namely, the disparity map-based bird's-eye-view mapping segmentation method and the edge distance weighted conditional random field (CRF)-based segmentation method. Our experimental results show that the proposed algorithm outperforms conventional algorithms. The improvements in performance range from 10.8 % to 20.5 % increase in F-measure.FALS

Degradation behavior of 21700 cylindrical lithium-ion battery cells during overdischarge cycling at low temperatures

Lithium-ion battery (LIB) cells are prone to overdischarge or overcharge when connected in series or parallel as a module or pack for large-format applications, such as electric vehicles (EVs) because of variations in battery capacities and difficulty in maintaining similar state-of-charge (SOC) of every single battery. However, the thermo-electrochemical behavior of LIBs during overdischarge has not been investigated at low temperatures. This study unveils the thermo-electrochemical behavior of overdischarged 21700 cylindrical LIB cells at −20 °C and 25 °C. Also, a thermo-electrochemical model was built to explain the heat generation within the cells and correlate them with the observed electrochemical characteristics. It was found that contrary to the severe cell degradation observed in the overdischarged cell compared to the standard cell at 25 °C, both cells show similar degradation behavior under low temperature cycling conditions. Thus, at low temperatures, overdischarge does not adversely affect cell degradation as observed at room temperature. This was attributed to the significant increase in the internal temperature, which results in improved electrochemical characteristics of the cell. © 2023FALS