Determination of Hydrofluoric Acid Formation During Fire Accidents of Lithium-Ion Batteries with a Direct Cooling System Based on the Refrigeration Liquids

To avoid overheating of the batteries, which could lead to a fire, Lithium-ion batteries are provided with a thermal management system using refrigeration liquids. Since some of the commercial dielectric liquids used as refrigeration liquids contain halogens, their presence will contribute to a formation of hazardous emissions such as hydrofluoric acid during a potential fire. In this study, a simulation of a high temperature accident has been performed for lithium-ion batteries cooled with the direct immersion cooling systems using single-phase dielectric liquids to define their contribution to HF formation. Four commercial refrigeration liquids based on perfluoropolyethers, hydrofluoroether and polyalphaolefin were investigated in this work. By simulation of a fire, it was observed that the refrigeration liquids delayed the smoke formation by a factor of 2 to 2.5 in comparison to the case when the battery was burned without the cooling liquid. By analysis of the fluoride concentration in the washing system, it was determined that without the refrigeration liquid approximately 46.8\ua0mmol/l of [F] was captured after the fire. When refrigeration liquids based on two perfluoropolyethers and hydrofluoroether were applied, the fluoride concentration in the washing system was 259\ua0mmol/l, 173\ua0mmol/l and 145\ua0mmol/l, respectively. This work also proposed the reaction mechanisms of the refrigeration liquid\ub4s decomposition during a fire. It was concluded that the refrigeration liquid based on polyalphaolefin does not contribute to the additional formation of hydrofluoric acid due to the chemical stability and low content of fluoride and can be considered as a more sustainable alternative for a direct cooling system for Lithium-ion batteries

Finding Prototypes Through a Two-Step Fuzzy Approach

Usually, the aim of cluster analysis is to build prototypes, i.e., typologies of units that present similar characteristics. In this paper, an alternative approach based on consensus clustering between two different clustering methods is proposed to obtain homogeneous prototypes. The clustering methods used are fuzzy c-means (that minimizes the objective function with respect to centers of the groups) and archetypal analysis (that minimizes the objective function with respect to extremes of the groups). The consensus clustering is used to assess the correspondence between the clustering solutions obtained and to find the prototypes as a compromise between the two clustering methods

Elucidation of the mechanisms underlying the angiogenic effects of ginsenoside Rg(1) in vivo and in vitro.

Metadata onlyThe major active constituents of ginseng are ginsenosides, and Rg(1) is a predominant compound of the total extract. Recent studies have demonstrated that Rg(1) can promote angiogenesis in vivo and in vitro. In this study, we used a DNA microarray technology to elucidate the mechanisms of action of Rg(1). We report that Rg(1) induces the proliferation of HUVECs, monitored using [(3)H]-thymidine incorporation and Trypan blue exclusion assays. Furthermore, Rg(1) (150-600 nM) also showed an enhanced tube forming inducing effect on the HUVEC. Rg(1) was also demonstrated to promote angiogenesis in an in vivo Matrigel plug assay, and increase endothelial sprouting in the ex vivo rat aorta ring assay. Differential gene expression profile of HUVEC following treatment with Rg(1) revealed the expression of genes related to cell adhesion, migration and cytoskeleton, including RhoA, RhoB, IQGAP1, CALM2, Vav2 and LAMA4. Our results suggest that Rg(1) can promote angiogenesis in multiple models, and this effect is partly due to the modulation of genes that are involved in the cytoskeletal dynamics, cell-cell adhesion and migration