基于优化算法的弹药贮存寿命预测方法

目的 实现对缺失及不足的制导弹药贮存失效数据预测及补充的能力。方法 首先通过4种不同的预测算法（GA-BP、PSO-BP、GA-SVM、PSO-SVM）,对自然贮存条件下弹药贮存失效数据进行预测,其次根据最小二乘拟合法,实现弹药贮存寿命评估模型的构建,再通过寿命评估模型,计算出不同方法下对应的贮存寿命。结果 通过不同模型的构建,4种预测方法与无优化条件下均能实现弹药贮存失效数据的预测,并且在规定可靠度,GA-BP和PSO-BP预测精度比另外2种方法更低。结论 GA-SVM与PSO-SVM更适合弹药贮存失效数据的预测,且效果更好。     

滤膜在颗粒物无机元素监测中的适用性研究

筛选国内外12个制造商的玻璃纤维、石英、特氟龙、聚丙烯、乙酸纤维、硝酸纤维和混合纤维等7类材质34种滤膜,测定滤膜中的铍、铬、锰、钴、镍、铜、锌、砷、钼、镉、锡、锑、铊和铅等14种元素含量,探讨不同材质滤膜中各元素的质量分数分布,采用大气固定源污染物排放标准中项目限值和分析方法标准中质量控制要求,对铜、锌之外的12种元素进行适用性评价。结果表明:玻璃纤维滤膜比其他材质滤膜中无机元素的质量分数高1～5个数量级,进口玻璃纤维滤膜中铬、镍、砷、镉等4种元素质量分数高于多数国产玻璃纤维滤膜,国产A、H玻璃纤维滤膜中14种元素质量分数相对较低;仅混合纤维滤膜中镉、铅的测定值浓度低于最严标准限值的10%,玻璃纤维滤膜之外的其他材质滤膜均能满足监测其余10种元素的本底需求。     

固定污染源排放可凝结颗粒物采样方法综述

综述了国内外固定污染源可凝结颗粒物(CPM)冲击冷凝法和稀释冷凝法2种采样方法,指出CPM是固定污染源排放颗粒物的重要组成部分,国内对于固定污染源CPM排放的监测和研究尚处于起步阶段,缺乏必要的CPM采样标准方法。通过分析2种采样方法的优缺点,提出冲击冷凝采样法需进一步降低SO_2等水溶性气体的影响,提高气相CPM冷凝效果及超细颗粒态CPM的捕集效率;稀释冷凝法需提高采样装置的便携性实现可过滤颗粒物(FPM)和CPM的分离采样,提高采样管路壁面颗粒物回收率。同时,针对我国固定污染源如燃煤电厂大量使用湿法脱硫设备的情况,CPM采样方法需提高对低温高湿且夹带液滴烟气采样的适用性。     

超低排放下燃煤电厂颗粒物排放特征分析研究

选取6家经过超低排放改造的燃煤电厂,对湿法脱硫(WFGD)和湿式电除尘器(WESP)进出口烟气中TPM、PM_(10)、PM_(2.5)、PM_1进行测试,分析研究超低排放下燃煤电厂颗粒物的排放特征及电除尘器后净化设备对颗粒物的脱除效果。结果表明,6家电厂TPM、PM_(10)、PM_(2.5)、PM_1排放浓度分别为0.75~2.36、0.71~2.12、0.65~1.96、0.51~1.57 mg/m~3。分析烟气中颗粒物粒径分布可知,除尘器后,PM10占TPM质量比低于40%,且比例随烟气经过WFGD和WESP而逐渐降低。WFGD对PM2.5有较好的脱除效果,而WESP对PM1脱除效果显著。为满足超低排放标准,6家电厂除尘器后脱除设备综合除尘效率大多在85%以上。计算得到6家电厂TPM、PM_(10)、PM_(2.5)、PM_1排放因子,与超低排放改造之前同等级燃煤电厂相比,6家电厂不同粒径颗粒物排放因子均显著降低,也远低于西方发达国家燃煤电厂颗粒物排放因子。     

Design and analysis of artificial bee-colony-based MPPT algorithm for DFIG-based wind energy conversion systems

In this article, the proposed maximum power point tracking (MPPT) method is designed by taking rotor speed as an optimization problem, which is solved by artificial bee colony (ABC) algorithm to generate the maximum power output. The main advantage of this algorithm is that its optimal solution is independent of the initial positions and requirement of lesser number of control parameters, which leads to simple and robust MPPT algorithm than other algorithm. Furthermore, the hill climb search and particle swarm optimization-based MPPT algorithm are also discussed and the results obtained by these are compared to verify the effectiveness of proposed algorithm. Simulations for MPPT control along with doubly fed induction-generator-based wind energy conversion system is carried out in MATLAB/Simulink environment. Three statistical methods are used to evaluate the accuracy of each MPPT algorithm. All results are analyzed and compared under randomly selected wind as well as real wind speed configuration. Comparison of both numerical and simulation results under two different varying wind speed conditions strongly suggest that the proposed ABC-based MPPT algorithm is superior than other two MPPT algorithms.     

The effect of cerium oxide additive on the performance and emission characteristics of a CI engine operated with rice bran biodiesel and its blends

In this study, the rice bran oil (RBO) has been converted into methyl ester with an aid of transesterification reaction. Chemically, transesterification means conversion of triglyceride molecule or a complex fatty acid into alcohol and ester by removing the glycerin and neutralizing the free fatty acids. The B20 blend samples [80% diesel + 20% biodiesel] were prepared for each methyl ester obtained from RBO and then the cerium oxide (CeO₂) nanoparticles were added to the each B20 blend samples at a dosage of 50 ppm and 100 ppm with an aid of ultrasonicator. Moreover, in the absence of any engine modifications, the performance and emission characteristics of those blend samples have been investigated from the experimentally measured values such as density, viscosity, cloud point, pour point, and calorific value while the engine performance was also analyzed through the parameters like exhaust gas temperature (EGT), brake specific fuel consumption (BSFC), brake thermal efficiency (BTE), exhaust emission of carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx). The experimental results reveal that the use of CeO₂ blended biodiesel in diesel engine has exhibited good improvement in performance characteristic and reduction in exhaust emissions.     

土壤剪切波速与标贯击数关系的统计分析

统计分析了细砂、中砂、粗砂、砾砂、粉质粘土和粘土的土壤剪切波速与标贯击数的关系,给出了相应的经验公式及适用埋深;采用方法 1和方法 2两种方法对细砂,中砂,粗砂,粉质粘土对土壤剪切波速与埋深及标贯击数进行了多元统计分析。结果表明:有必要将土类进行细分,再给出剪切波速与其标贯击数的回归关系;砾砂宜采用现场测试其剪切波速与标贯击数;两种方式都得到了较令人满意的结果,采用方法 1比方法 2略优。     

粗粒料湿化变形数值模拟研究

粗粒料湿化变形特性对土石坝静力稳定有着显著影响。目前开展的三轴试验和直剪试验研究,一般只能进行干样和饱和样的试验,而对于非饱和情况研究较少。基于粗粒料不同围压下湿化变形试验研究成果开展数值模拟研究,结果表明:湿化变形的影响可以通过改变细观剪切模量和细观摩擦系数来实现;随着颗粒破碎随饱和度和围压的增加,湿化后粗粒料的强度低、内聚力降低,但摩擦角变化不大。     

铅蓄电池厂铅污染土壤清洗剂的筛选及清洗结果研究

为探索不同清洗剂对铅蓄电池厂区内铅污染土壤的去除效果及铅在不同粒径土壤清洗过程中的行为,本研究通过设定清洗剂的浓度梯度,对土样粒径分级、设定清洗时间等方法进行研究。结果显示EDTA和EDDS对铅具有最佳去除率(B点土107.19%和96.49%);盐酸对A点土最佳铅去除率为49.57%,B点、C点土在99.03%和89.93%;柠檬酸对3点位土的铅去除率最大为39.51%;鼠李糖脂对3份土铅去除率均低于10%。EDTA和EDDS在高浓度铅的去除中表现优势;柠檬酸适合去除中低浓度铅;盐酸的使用需考虑土壤本身情况。粗沙粒和细沙粒中的铅去除率高,粉粘粒的铅去除率低;最佳清洗时长为240min。此外,土壤本身理化性质对清洗剂效果的发挥有影响,清洗剂浓度过高可能降低清洗效率。该研究可为铅污染土壤清洗技术提供科学依据。     

紫外分光光度测定总氮的影响因素探讨

本文介绍了测定总氮过程中,不同消解方法、碱性过硫酸钾的稳定时间、悬浮物粒径对总氮测定的影响。实验表明:碱性过硫酸钾避光在冰箱中至少可保存一个月,悬浮物粒径对总氮的测定无影响,消解总氮时,可在压力锅加热到120℃开始计时,恒温消解30分钟,自然冷却。