Experimental study on thermal runaway risk of 18650 lithium ion battery under side-heating condition

To simulate the heat transfer process between lithium-ion batteries (LIBs), an electric heater with the same size and shape as LIB in this work is used to trigger thermal runaway event. The effect of state of charge (SOC), the power of heater, the cell spacing on thermal behavior of LIB was investigated as well the amount of transferred heat between the heater and LIB was calculated. The results indicate that 50% SOC is an unstable state for LIB, that a stronger jet flame becomes more likely when the SOC of LIB is higher than 50%. Additionally, the increased spacing, lower heating power and SOC can contribute to mitigate the severity of thermal runaway behavior. Further, the dominant path of heat transfer between the heater and LIB will also vary with operating conditions. The heat conduction through air is the main heat transfer path in tests with lower heating power. However, heat radiation will replace heat conduction as the primary heat transfer mode when there is a large temperature difference between the heater and LIB in tests with higher heating power. Understanding the leading heat transfer path between LIBs can provide valuable guidelines for the safety design of lithium-ion battery modules.     

热脱附法在测定空气中苯系物上的应用

对热脱附-气相色谱测定苯系物方法中的几种常用吸附剂进行了选择比较。结果表明,在测定苯、甲苯、乙苯、二甲苯以及苯乙烯时,TenaxTA/Carbograph1TD复合型吸附剂的综合吸附效率最好。TenaxTA/Carbograph1TD复合型吸附剂的检出限、精密度、准确度和保存期都得到了良好的结果,能够满足监测分析的要求。     

The need for bioaugmentation after thermal treatment of a TCE-contaminated aquifer: Laboratory experiments

A microcosm study was conducted to evaluate the need for bioaugmentation after a thermal treatment to anaerobically dechlorinate trichloroethene (TCE) to ethene. The microcosms were either: heated to 100 degrees C and slowly cooled to simulate thermal remediation while bioaugmenting when the declining temperature reached 10 degrees C; or kept at ambient groundwater temperatures (10 degrees C) and bioaugmented for comparison. Aquifer samples from three sediment locations within a TCE-polluted source zone were investigated in duplicate microcosms. In biostimulated (5 mM lactate) and heated microcosms, no conversion of TCE was observed in 4 out of 6 microcosms, and in the remaining microcosms the dechlorination of TCE was incomplete to cDCE (cis-dichloroethene). By comparison, complete TCE dechlorination to ethene was observed in 4 out of 6 heated microcosms that were bioaugmented with a highly enriched dechlorinating mixed culture, KB-1, but no electron donor, and also in 4 of 6 microcosms that were augmented with KB-1 and an electron donor (5 mM lactate). These data suggest that electron donor released during heating, was capable of promoting complete dechlorination coincident with bioaugmentation. Heated microcosms demonstrated less methanogenesis than unheated microcosms, even with elevated H2 concentrations and addition of KB-1, which contains methanogens. This suggests that the heating process suppressed the native microbial community, which can decrease competition with the bioaugmented culture and increase the effectiveness of dechlorination following a thermal treatment. Specifically, cDCE removal rates were four to six times higher in heated than unheated bioaugmented microcosms. This study confirms the need for bioaugmentation following a laboratory thermal treatment to obtain complete dechlorination of TCE.     

城市垃圾中生物质在热分析仪中燃烧的动力学模型研究

为了合理有效利用城市垃圾中的生物质能，实现城市垃圾的无害化、减量化、资源化利用，开发适合我国城市垃圾中生物质的焚烧技术，特地对昆明市城市垃圾中生物质进行了特性分析，并在热重分析天平上对其进行了动力学实验研究与分析。结果表明，城市垃圾中生物质的燃烧过程大致可以分为四个阶段，即脱水干燥阶段、挥发份的析出和燃烧阶段、过渡阶段和固定炭燃烧阶段。城市生活垃圾中生物质具有着火温度低、燃尽率高等特点。通过对热重（TG）、差示扫描曲线（DTA）的深入分析，对城市垃圾中生物质的燃烧动力学参数进行了研究，为实现城市垃圾无害化提供理论与技术的支持。     

Destratification and oxygenation efficiency of a water-lifting aerator system in a deep reservoir: Implications for optimal operation

Thermal stratification is a common phenomenon in lakes and reservoirs and has a significant influence on water quality dynamics.Heihe Reservoir is a canyon-shaped reservoir in Shaanxi Province with strong thermal stratification.Therefore,eight water-lifting aerators(WLAs) were installed in this reservoir,which could overcome thermal stratification and increase oxygenation with gas flows between 20 and 50 m3/hr,and oxygenate the hypolimnion with gas flows less than 20 m3/hr.To examine the destratification efficiency of the WLA system,we used a threedimensional hydrodynamic module based on MIKE 3 to simulate the thermal structure of Heihe Reservoir and compared the simulations with measured data.Results showed that operation of the WLA system promoted water mixing and effectively oxygenated the hypolimnion.Through the established energy utilization assessment method,the energy utilization efficiency of the WLA system was between 5.36% and 7.30%,indicating the capability of the technique for destratification in such a large reservoir.When the surface water temperature dropped to the theoretical mixed water temperature calculated by the energy utilization assessment method,reducing gas flow could save energy.This would prevent anaerobic conditions from occurring in the bottom water and maintain good water quality in Heihe Reservoir.     

Thermal internal boundary layer and its effects on air pollutants during summer in a coastal city in North China

The thermal internal boundary layer(TIBL) is associated with coastal pollution dispersion,which can result in high concentrations of air pollutants near the surface of the Earth. In this study, boundary layer height data which were obtained using a ceilometer were used to assess the effect of the TIBL on atmospheric pollutants in Qinhuangdao, a coastal city in North China.A TIBL formed on 33% of summer days. When a TIBL formed, the sunshine duration was 2.4 hr longer, the wind speed was higher, the wind direction reflected a typical sea breeze, and the boundary layer height was lower from 9:00 LT to 20:00 LT compared to days without a TIBL. If no TIBL formed, the average concentrations of PM_(2.5) and PM_(10) decreased with increasing boundary layer height. However, when a TIBL was observed, the average concentrations of PM_(2.5) and PM_(10) increased with increasing boundary layer height. Because the air from the sea is clean, PM_(2.5) and PM_(10) concentrations reached minimums in the daytime at 16:00 LT. After16:00 LT, the PM_(2.5) and PM_(10) concentrations increased rapidly on days when a TIBL formed,which indicated that the TIBL leads to the rapid accumulation of atmospheric pollutants in the evening. Therefore, the maximum concentrations of particulate matters were larger when a TIBL formed compared to when no TIBL was present during the night. These results indicate that it is suitable for outdoor activities in the daytime on days with a TIBL in coastal cities.     

用于气相色谱分析的样品导入技术及其应用

综述了几种用于气相色谱分析的绿色环保型样品导入技术,如静态顶空技术、吹扫捕集技术、固相微萃取技术和热脱附技术的原理及应用情况,并对这几种方法进行了比较。     

Investigation of Synthesis of Copolymers from the Waste Products of Industrial Oil Refinement having Adhesion Properties and Strength to the Thermal Destruction

In this study, the waste products of industrial vegetable oil refinement were transformed into the glycidyl ester for preventing the effects of them to the environment, the ways for evaluating them in polymer chemistry were investigated, copolymers having high adhesion property and strength to the thermal destruction were synthesized and the area of their usage was determined. For this reason, the waste product of sunflower oil refination as a vegetable oil in the industry; soap stock (SS) was converted to the unsaturated glycidyl esters by the interaction with epichlorohidrine in the alkaline medium. After that the copolymerization of synthesized unsaturated glycidyl esters and the other waste product of oil refinement fatty acid (FA) with styrene in the radicalic initiator medium were investigated and copolymers that have high strength to the thermal destruction and adhesion property were synthesized. From the results of TGA and DTA analysis, it was determined that synthesized copolymers have low loss of weight at high temperature. The structures of copolymers were fixed by spectral and chemical analysis methods.     

Thermal decomposition kinetic of liquid organic peroxides

This study demonstrates the application of isothermal calorimeter for investigating the thermal decomposition of several liquid organic peroxides, such as t-Butyl peroxy acetate (TBPA), Di-tert butyl peroxide (DTBP), and Cumene hydroperoxide (CHP). The decomposition mechanism and kinetic can be identified from case to case. TBPA and DTBP undergo first order reaction, whereas CHP occurs autocatalysis. Accurate kinetic can be assessed on the basis of discerning these various schemes of given samples. Consequently, the thermal runaway or reactive hazards potential of organic peroxides can be determined, for instance as a self accelerating decomposition temperature (SADT).     

Rain-out investigation: Initial droplet size measurement

Droplet size distribution inside water flashing jets and corresponding rain-out fraction were measured. Mass distribution showed that a few droplets are ‘large’ (d>150 μm) and count for more than 85% of the liquid mass in the jet because of their large individual mass. This could be due to incomplete thermal fragmentation. It could explain the rain-out falling near the orifice or pipe exit.