An optimized numerical method to pre-researching the performance of solid-phase oxygen control in a non-isothermal lead–bismuth eutectic loop

In the present work,a new transient calculation method for parameters that can be used to evaluate the ability of oxygen control in a non-isothermal lead-bismuth eutectic(LBE)loop with solid-phase oxygen control was proposed.It incorporates the dissolution process of PbO particles and the oxygen mass transfer process,and an optimized method was used for finding out the optimized oxygen mass transfer coefficient.In numerical terms,three mass transfer models were simultaneously applied,and comparisons of calculated and experimental results from the CRAFT loop indicated that the optimized calculation method and these new oxygen mass transfer models were correct and applicable to other LBE loops.Through this calculation method,we aimed to optimize prediction of the distribution of oxygen and iron concentrations,time taken to establish the steady state of oxygen,and maximum dissolution/precipitation rates of corrosion products and corrosion depth across the entire LBE loop.We hope that this work will provide a potential reference for designing a more intelligent oxygen control system in the future.

Air flow control based on optimal oxygen excess ratio in fuel cells for vehicles

Air flow control is one of the most important control methods for maintaining the stability and reliability of a fuel cell system, which can avoid oxygen starvation or oxygen saturation. The oxygen excess ratio （OER） is often used to indicate the air flow condition. Based on a fuel cell system model for vehicles, OER performance was analyzed for different stack currents and temperatures in this paper, and the results show that the optimal OER was affected weakly by the stack temperature. In order to ensure the system working in optimal OER, a control scheme that includes an optimal OER regulator and a fuzzy control was proposed. According to the stack current, a reference value of air flow rate was obtained with the optimal OER regulator and then the air compressor motor voltage was controlled with the fuzzy controller to adjust the air flow rate provided by the air compressor. Simulation results show that the control method has good dynamic and static characteristics.

Reactive oxygen species—Control and management using amphiphilic biosynthetic hydrogels for cardiac applications

The reactive oxygen species (ROS) originated from endogenous and exogenous sources play a dominant role in the initiation and propagation of several diseases. It is therefore an urgent need to explore substances capable of encountering the ROS and resist the damage caused by ROS. The present paper deals with various aspects of generation and implications of ROS in the management of myocardial infarction. The use of biosynthetic amphiphilic biodegradable hydrogels in the control and management of ROS in myocardial infarction was studied using a biosynthetic hydrogel (PA-PEGDA) comprising poly(propylene fumarate)-co-alginate copolymer cross-linked with calcium and polyethylene glycol diacrylate (PEGDA). The effect of ROS on the cell growth was studied using H2O2 as model ROS molecule. The present hydrogel resists the penetration of ROS in the cell which was evident from the live/dead assay, increased intra cellular GSH levels when compared with the H2O2 treated positive and curcumin treated negative control cells. The Comet assay reveals genomic integrity of the cells exposed to the present hydrogel. The hydrogel is a promising injectable material for the management of myocardial infarction and ischemia.

Simulation of VGT control based on charge oxygen concentration

A turbocharged diesel engine model was built with the GT-Power software,and experimentally verified.Then two different control variables for the control of the variable geometry turbocharger（VGT）were described,and their distinct effects on engine performance,i.e.NOxand soot emissions and fuel consumption,were simulated and compared on the basis of this model.The results showed that NOxemissions decreased obviously with the increase of exhaust gas recirculation（EGR）rate at constant boost pressure condition,but soot emissions and fuel consumption considerably increased.It was a good way to reduce NOxemissions without increasing fuel consumption and soot emissions when VGT was controlled to maintain the excess oxygen ratio unchanged as EGR rate increases.

Novel Oxygen Storage Components Promoted Palladium Catalysts for Emission Control in Natural Gas Powered Engines

A three-way catalyst comprised novel oxygen storage components for emission control in natural gas powered engines was prepared. The addition of novel oxygen storage components to the Pd/γ-Al2O3 catalysts resulted in improved activities of the fresh and aged catalyst by lowering the light-off temperature for methane in natural gas engines exhaust.

循环流化床锅炉节能减碳运行调控及工程验证

构建基于烟气中氧气体积分数及炉膛出口压力的锅炉运行协同控制模型,可以实时、准确地预测烟气中氧气体积分数的变化趋势,提前给定锅炉二次风机和引风机控制指令,显著减小了不同负荷条件下锅炉烟气中氧气体积分数、负压等关键运行参数的波动.在300 t/h循环流化床锅炉上的工业验证结果表明:利用协同控制模型可以提高锅炉运行控制的品质,锅炉变负荷工况条件下烟气中氧气体积分数控制在目标值±0.25%范围内,炉膛出口压力控制在目标值±45 Pa范围内的统计概率为99%.运行一周的统计结果表明,相比于原有控制,协同控制模型投运后单位产汽量耗煤可以减小1.508%,单位产汽量风机耗电可以减少1.886%.

市政污水生化处理过程中曝气控制系统研究进展

为了促进污水处理厂(WWTPs)的低碳可持续运营管理,近年来致力于改善出水质量、削减运营成本和降低温室气体排放的智能曝气控制技术蓬勃发展,但关于可持续污水处理厂的最佳曝气控制策略尚未达成共识。系统综述了曝气过程中溶解氧浓度对于N2O释放的影响,通过分析对比不同曝气控制策略的差异及优缺点,提出曝气控制策略进一步优化的建议,为实现市政污水处理厂溶解氧的综合科学管理提供理论支撑,旨在为污水处理行业提供科学依据和技术支持,促进环境保护和可持续发展。在曝气控制系统中加入N2O排放量化模型来实现出水水质、曝气能耗、温室气体排放三者之间的平衡是未来的关键研究方向,需开发更准确、更合适的温室气体量化模型、灵活的控制方法和智能曝气策略,以满足污水处理厂更多的需求。

沙滩椅体位及控制性降压下肩关节手术病人脑氧饱和度与脑部血流速度改变及其对术后神经认知的影响

目的分析沙滩椅体位及控制性降压下肩关节手术中脑氧饱和度(rScO_(2))与脑部血流速度的变化,及其对病人术后神经认知的影响。方法选取拟于本院以沙滩椅体位接受肩关节手术治疗的病人60例,均为美国麻醉医师协会(ASA)分级Ⅰ、Ⅱ级,在静脉全身麻醉及控制性降压干预下,于麻醉前、麻醉并转入沙滩椅体位后5 min、手术开始时以及手术开始后每隔20 min直至手术结束进行rScO_(2)、大脑中动脉血流速度(VMCA)和有创血压(心脏水平和耳道水平)的检测,并记录脑氧欠饱和事件(CDE)的发生。同时,于术前和术后24 h对病人进行神经认知能力测试。结果转入沙滩椅体位后所有病人的rScO_(2)和VMCA相比麻醉前都有所下降。经历CDE的病人耳道水平平均动脉压、rScO_(2)和VMCA均显著低于未经历CDE的病人,并且术后24 h时连线测试成绩也更低,组间差异有统计学意义(P<0.05)。结论对于ASA分级Ⅰ、Ⅱ级病人,沙滩椅体位及控制性降压下肩关节手术中部分病人的rScO_(2)和VMCA较麻醉前显著下降并发生CDE,进而对术后神经认知产生不利影响。

高压氧舱恒湿平压系统的设计

目的:设计一种高压氧舱恒湿平压系统,以消除舱内静电火花造成的危害,保证氧舱的安全运行。方法:该系统的硬件主要由加湿装置、除湿装置、平压装置、主控制器、压力传感器、温湿度传感器等组成。其中,加湿装置主体为经过特殊加工后的防爆过滤瓶;除湿装置采用工业级风机过滤单元(fan filter unit,FFU),由蒸发器、冷凝器、风轮3个部分组成;平压装置主要由电磁阀和减压管路组成;主控制器选用EX3G-C系列PLC触摸屏一体机,温湿度传感器选用NWSF-1AT型号温湿度传感器,压力传感器选用TXYS-G1K2HN3型变送器。系统的软件控制程序采用指令表语言编程,通过PID(proportional-integral-derivative)控制算法实现整体控制。结果:经过测试,该系统可使高压氧舱内相对湿度恒定在70%,使舱内极难产生静电。结论:该系统能够调节氧舱内的湿度、减少静电火花产生,保证舱内治疗的安全。

基于最大净功率输出的PEMFC阴极供气系统优化控制研究

通过建立质子交换膜燃料电池(PEMFC)阴极供气系统数学模型,分析空气压缩机电压和背压阀开度对系统净功率输出的影响;针对负载电流变化,研究PEMFC系统对应的最优过氧比和最优阴极压力,建立最大输出净功率-过氧比-阴极压力寻优表;考虑过氧比和阴极压力之间的耦合关系,基于辨识出的传递函数矩阵,设计针对空气压缩机电压和背压阀开度的前馈解耦控制器,优化氧气供给和压力控制,并进行相应的仿真验证。结果表明,所提解耦控制器能有效减小过氧比和阴极压力之间的耦合影响,在实现最大净功率闭环控制的同时,具有更快的响应速度和更小的超调量。

Simulation of oxygen transfer in liquid lead under influence of nanoparticles by using lattice Boltzmann method

Oxygen transfer presents a serious challenge in the application of liquid lead as a nuclear coolant in advanced reactors. To mitigate corrosion by liquid lead in contact with steel, carefully controlling the oxygen concentration has been used as an effective way. Oxygen needs to mix in liquid lead uniformly and quickly. To enhance oxygen transport in liquid lead, nanoparticles are added to the liquid metal. In the current study, a lattice Boltzmann method is applied to investigate natural convection of copper/lead and aluminum oxide/lead in two-dimensional simplified container. Two thermal boundary cases are evaluated in order to check the effect of different natural convection flow patterns on oxygen transport. Some useful information are obtained such as improvement in natural convection and reduction in oxygen equilibrium time.

优化污泥回流方式对多级AO-MBR工艺的影响

采用处理水量为0.15 m^(3)/h的中试装置,开展多级AO-MBR工艺处理低C/N城市污水试验研究,通过优化污泥回流方式、溶解氧及污泥浓度控制等措施,降低高溶解氧污泥回流对前端生化池的影响,实现出水水质达到地表水准Ⅳ类标准(TN除外)。结果表明,在耦合MBR工艺的形式下,经过生化池多级回流能显著保证各反应区的溶解氧环境,保持各反应区的污泥浓度平衡,进一步提高出水水质。在水温低于12℃、进水TN质量浓度为23~33 mg/L时,采用回流方式4能稳定保证TN去除率达到60%以上,实现出水TN质量浓度达到10 mg/L左右;进水TP质量浓度为2~4 mg/L时,TP去除率达到85%以上,实现出水TP质量浓度低于0.3 mg/L的要求。

体外膜肺氧合支持治疗患者医院感染危险因素及防控的研究进展

体外膜肺氧合(ECMO)支持治疗患者是医院感染的高风险人群。本文综述了ECMO支持治疗患者医院感染的危险因素与防控措施,并从患者相关因素、治疗相关因素及环境与设备因素阐明该人群医院感染的危险因素;防控措施涵盖合理置管、拔管操作,清洁消毒,建立专业团队,加强感染监测,监测药物浓度,导管材料的选择。本文旨在为医务人员提供前沿指导,加强对该领域的专业认知,以实现在ECMO支持治疗中最大限度地降低感染风险,提升患者的生存质量。

阀冷系统溶解氧在线监测技术的研究及应用

为进一步提升换流阀冷却系统的运行可靠性,更准确地监测阀冷系统内冷却水溶解氧信息,结合阀冷系统的实际应用环境,研究了溶解氧测量仪的工作原理和不同测量方法的优缺点,给出了对应的溶解氧测量仪选型方案以及使用过程中的注意事项。

成人体外膜氧合辅助期间感染防控专家共识

感染是体外膜氧合(ECMO)辅助期间常见的并发症。感染的发生不仅增加患者治疗费用,而且会影响患者的预后导致更高的病死率。目前国内外各ECMO中心对于感染的防控尚缺乏统一的标准。因此,中国心胸血管麻醉学会体外生命支持分会联合浙江省ICU质量控制中心,组织专家根据国内外最新研究结果,参考相关指南,结合流行病学及临床实践,撰写了本专家共识,以期规范ECMO辅助期间的感染防控,降低感染的发生率及提高控制率,改善患者的预后。

多段AAO污水处理厂精确曝气系统设计与调试

为了能够更好地解决污水处理过程中经常遇到的曝气不足、出水氨氮超标,曝气过量反硝化不好导致的总氮超标、能耗浪费等问题,以深圳市某污水处理厂多段AAO处理工艺为研究对象,介绍了在生化池中引入精确曝气系统的设计和调试情况,并结合实际运行情况对精确曝气控制系统的效用进行了分析和总结。

氧量最优控制系统设计与工业应用在污染物排放控制中的效果评估

随着我国污染物排放标准的更新与优化,当前火电厂的发展面临着极大挑战。在火电厂电能生产过程中,会产生大量烟气,如果没有对这些烟气进行有效处理,会引发严重的大气污染,影响我国生态文明建设效果,也不利于火电厂的长远可持续发展。因此,需要采取一定措施对烟气污染物排放进行控制。将氧量最优控制系统应用在火电厂污染物排放控制中,有突出效果。文章主要探讨氧量最优控制的重要性,并对氧量最优控制系统的设计原理和结构组成进行探索,明确在火电厂中,氧量最优控制系统设计的效果,为火电厂污染物排放控制管理提供新的方向。

控水增氧条件下不同施氮水平对水稻生长的影响

以水稻“中早39”为试验材料,采用盆栽试验,研究在控水增氧条件下不同施氮水平对水稻根系形态、根系活力、根系氮素代谢酶活性、植株光合特性和植株干重的影响。结果表明,在相同的控水增氧条件下,随施氮量的增加,水稻同一生育期的总根长、根表面积、根体积和平均根直径、根系活力、根系硝酸还原酶(NR)活性和谷氨酰胺合成酶(GS)活性、叶片净光合速率(Pn)、叶片蒸腾速率(Tr)、叶片叶绿素含量(SPAD)、根系及秸秆干重均呈先增后降的趋势,以施氮量180 kg/hm^(2)控水增氧处理为峰值;同一施氮水平的控水增氧处理较不控水增氧处理,水稻同一生育期的上述指标均显著增加;施氮量180 kg/hm^(2)控水增氧处理较施氮量0 kg/hm^(2)控水增氧处理、施氮量180 kg/hm^(2)不控水增氧处理开花期的根系活力分别增加127.6%、26.4%,孕穗期根系NR活性分别增加41.2%、88.7%,黄熟期根系干重分别增加257.2%、20.0%,黄熟期秸秆干重分别增加161.2%、16.4%。

基于模糊PID的供氧压力自动控制技术研究

现有的供氧压力自动控制技术,主要还是注重供氧,而不能使供氧压力保持稳定。为此,论文开展基于模糊PID的供氧压力自动控制技术的研究。为保证数据准确,先采集常规氧气剩余浓度数据,将所采集的数据导入自动控制供氧流程中得到输出信号使控制开关自动运行,再引入模糊PID算法确保自动供氧控制器稳定。通过实验对比证明,基于模糊PID的供氧压力自动控制技术比其他的供氧压力自动控制技术更稳定。

浅析危废焚烧工程锅炉烟气氧含量测量与控制

锅炉烟气氧含量能反应回转窑及二燃室燃烧状况,是危废焚烧工艺生产装置稳定运行的重要工艺参数之一。本文介绍危废焚烧工程的氧含量分析仪选型及氧含量自动控制方案,从氧含量分析仪比选、安装位置、安装方式及影响氧含量波动的因素等方面进行描述,提出氧含量分析仪的选用及控制策略,以达到准确测量及实时自动控制的目的,实现危废焚烧生产装置经济、安全、稳定、高效的运行。