Inhibiting effects by Fe2O3 on combustion and explosion characteristics of ABS resin

The global increase in the use of, and reliance on, plastics has prompted the demand for acrylonitrile-butadiene-styrene (ABS) resin in various fields. With this increased requirement, numerous failures have occurred in the ABS process. Those incidents, resulting from electrostatic discharge, powder accumulation, heat accumulation, construction sparks, and plant fires, have caused dust fire and explosions.In this study, the ABS resin was gleaned from the site and tested for its explosion parameters, including minimum ignition temperature of dust cloud (MIT_C), minimum ignition energy (MIE), and minimum explosion concentration (MEC). To improve loss prevention in the manufacturing process, ferric oxide (Fe₂O₃) as an inert additive was added in the ABS powder. According to the MIE test, Fe₂O₃ has an apparent inhibiting effect on dust explosion for the ABS dust. With the proportion of Fe₂O₃ increased from 25 to 50 mass% in ABS, the MIE increased from 67 to 540 mJ. The explosion tests via 20-L apparatus indicated that Fe₂O₃ mixed with ABS could not increase the MEC significantly. However, the explosion pressure dropped by increasing in the ratio of Fe₂O₃ in ABS. This inerting strategy of ABS was deemed to substantially lessen the probability and severity of fire and explosion.     

Thermal hazard and decomposition kinetics of 1-butyl-2,3-dimethylimidazolium nitrate via TGA/DSC and FTIR

1-Butyl-2,3-dimethylimidazolium nitrate ([Bmmim][NO₃]), a kind of versatile and novel ionic liquids, is widely applied in the modern petrochemical industry. Nevertheless, its thermal hazard safety data at high temperature or thermal disturbance conditions are currently unavailable. Therefore, this study aimed to characterize the thermal risk of [Bmmim][NO₃] through auto-ignition temperature measurements, flash point analysis, thermal gravimetric analysis/differential scanning calorimetry (TGA/DSC), TGA-Fourier transform infrared spectroscopy (TGA-FTIR) and thermal decomposition kinetics analysis. Additionally, [Bmmim][NO₃] was examined using isothermal thermogravimetric analysis at different temperatures (220, 230, 240, 250, 260 and 270 °C). The experimental results show that the flash point of [Bmmim][NO₃] is 305.70 ± 9.30 °C and the auto-ignition temperature is 341.00 ± 21.60 °C with an ignition delay time of 8.6 s. In addition, using the nitrogen atmosphere TGA data to calculate the activation energy according to the Friedman, Kissinger and Flynn-Wall-Ozawa methods, roughly the same results were obtained. Finally, TGA-FTIR results show that [Bmmim][NO₃] produced acetylene, butane, butanol and carbon dioxide during the thermal decomposition process. This study could provide data support and some guidance for the thermal hazard assessment and safety control of [Bmmim][NO₃] during its use and storage.     

取芯过程中煤芯温度分布特征模拟研究*

针对取芯过程瓦斯解吸受煤芯的温度影响不明,造成煤层瓦斯含量测不准的问题,开展对取芯过程煤芯温度分布特征研究。采用自主研制的取芯管自动测温装置在赵固二矿原生结构煤层（f=1.71）进行深度20 m的取芯试验,获得取芯管管壁温升变化规律,变化曲线分为4个阶段:缓慢上升、加速上升、减速上升、缓慢下降阶段;应用COMSOL建立含瓦斯煤传热模型,将管壁的温度变化设置为边界条件,模拟取芯过程煤芯与管壁之间的热交换。结果表明:在取芯时间30 min内,煤芯平均温度快速上升,之后上升速度趋于平稳;在煤芯内,相同时刻,等间距的轴向与径向距离,径向较轴向的温度梯度较大,径向传导快于轴向传导;取芯过程煤芯径向温度Ta与径向距离d、时间t满足指数函数关系。研究结果可为测定取芯过程煤芯的瓦斯损失量提供参考依据。     

Management and Limnology Interact to Drive Water Temperature Patterns in a Middle Rockies River‐Reservoir System

This study seeks to improve understanding of temperature patterns in reservoir outflows. We examined water temperatures in an irrigation storage reservoir, Island Park Reservoir, and its outflow, Henry’s Fork of the Snake River in eastern Idaho. Our objectives were to (1) quantify the extent to which daily temperature ranges in the reservoir outflow deviated from other reaches of the Henry’s Fork, and (2) test whether the reservoir’s net volume change during the summer — expressed as the volume of water remaining in the reservoir on September 1 — predicted mean summer temperature in the outflow. Two years of temperature data showed dampened diel temperature cycles in the reservoir outflow. Model selection with 17 years of climatic, hydrologic, and reservoir management variables found mean summer temperature in the outflow was best predicted by September 1 reservoir volume and average summer air temperature. Two years of weekly reservoir thermal profiles indicated large changes in reservoir volume eliminated cool hypolimnetic water and encouraged mixing, allowing warm epilimnetic water to be discharged into the outflow. Increases in future drought frequency and severity and increases in summer air temperatures could increase the frequency of occurrence of high mean summertime water temperatures in the outflow. Our study provides important information for local managers by quantifying influences on outflow temperatures and the downstream river ecosystem.     

Extrinsic modeling and simulation of helio-photovoltaic system: a case of single diode model

Simulation of helio-photovoltaic system is continuously undergoing revolution through diverse parameter modifications which closely mimic the experimental data. In retrospect, the current work has presented a nonlinear modification of equivalent circuit parameters and simulated the same for different semiconductors (crystalline and thin films); furthermore, established a mathematical relation between the coefficients of solar irradiance and module temperature (SIMT); moreover, investigated the influence of SIMT on the model parameters. The simulation upshot reveals that increment in solar irradiance (SI) intensifies the output current whereas an increase in module temperature (MT) diminishes the output voltage; the SIMT coefficients developed validated well with the manufacturers data; the influence of SI was evident on the photon current, diode current, and shunt resistance whereas the effect of MT was pronounced on the diode current, ideality factor, and shunt resistance. Thus, the provision made by this work is essential for advanced design and simulation of helio-photovoltaic systems.     

地下煤火回风裂隙火风压分布实验研究

利用煤田露头火区模拟实验装置,通过对煤火燃烧过程中出风裂隙内气体温度的监测,发现裂隙内气体的温度沿裂缝逐渐降低并成指数衰减分布。通过分析得到火区裂隙温度的分布方程并计算得到了裂隙内火风压分布方程,得出煤田火区火风压的影响因素主要有自燃煤层温度、自燃深度和裂隙倾角。     

含风电的电力系统低碳经济调度

含风电场的电力系统调度是一个多目标优化问题。运用机会约束方法,建立了包括低碳化和发电成本两个目标函数的调度模型,在充分考虑环境保护效益的同时,提出了风险成本的概念,使得发电成本更切合工程实际。在改进自适应遗传算法的基础上,引入了pareto最优解集方法,充分发挥了遗传算法的全局搜索能力和pareto求解多目标问题的潜力。通过实际调度案例验证了所提算法的合理性。     

温度对多孔射气介质氡析出影响试验研究

为了研究围岩中温度对氡析出率的影响,选取某铀矿铀尾矿矿砂试样,根据相似准则设计并制作了测量多孔射气介质氡析出率的室内试验装置。采用RAD-7氡测量仪,运用等时间间隔取样方法测量氡浓度。采用对照试验的方法研究了温度对多孔射气介质氡析出率的影响规律。试验结果表明,在自然压力下,在温度为20℃到60℃范围内,随着温度的升高,多孔介质氡析出率逐渐增大,并且氡析出率与温度符合线性函数关系。     

浮射流特性对工业建筑室内污染物分布影响研究

在前人实验数据误差分析的基础上,基于空间热及污染物分布相关理论,采用数值模拟方法,对不同浮射流强度下热及污染物分布过渡区进行研究。研究表明,浮射流强度较低(如373 K)时,污染物分布过渡区将增厚,部分污染物由于扩散作用将与热出现明显分离现象,扩散至建筑下部空间,影响工艺及人员健康。     

UASB反应器反硝化处理工业废水

采用絮状污泥成功启动升流式厌氧污泥床(UASB)反应器处理含甲酸、苯胺、环已酮、NO3-等的工业废水。UASB反应器以低负荷启动,10天后逐渐提高进水COD,出水COD保持在710~770 mg/L,COD去除率为40%~60%;出水TOC保持在115~314 mg/L,TOC去除率由60.3%逐渐升高至87.2%,最终维持在81%左右;出水中ρ(NO3-)维持在134~176 mg/L,NO3-去除率为90%左右,系统稳定后NO3-去除率几乎为100%。在进水COD容积负荷不超过5.00 kg/(m3·d)的条件下,实际COD容积负荷稳定在2.00 kg/(m3·d)左右,实际TOC容积负荷稳定在1.00 kg/(m3·d)以上。当进水COD容积负荷不大于4.48 kg/(m3·d)时,COD去除率为55%~74%,TOC去除率为63%~87%,NO3-去除率大于95%。