基于表面活性剂的斜板洗涤器脱除憎水颗粒研究

选取十六烷基三甲基溴化铵(CTAB)、十二烷基苯磺酸钠(SDBS)、月桂醇聚氧乙烯(9)醚(AEO-9)和壬基酚聚氧乙烯醚(OP-10)配制成4种单一表面活性剂洗涤液,采用新型斜板洗涤器对憎水性炭粉进行湿法除尘实验,探讨表面活性剂种类、入口含尘浓度、空塔气速和液气比(L/G)等参数对除尘效率(η)和压降(ΔP)的影响,评价斜板洗涤器的脱水性能.结果表明,新型斜板洗涤器除尘效率高,压降小,脱水性能良好;4种表面活性剂均能较大程度提高除尘效率,其中AEO-9的脱除效果最佳;当AEO-9浓度为0.07mmol/L,入口含尘浓度为5g/m3,L/G为1.0L/m3,空塔气速为2.5m/s时,除尘效率高达99.99%;入口含尘浓度对ΔP的影响较小,L/G和空塔气速对ΔP影响较明显;实验范围内出口含湿量小于11g/kg(干).     

球阀处硫颗粒运移沉降规律数值模拟研究

元素硫在集输管道中沉积会引起堵塞和腐蚀问题,球阀处是集输管道中较易出现大量硫沉积的部位之一。为此,采用数值模拟的方法研究高含硫天然气中析出的硫颗粒在球阀处的运移沉降规律,选用雷诺应力模型模拟球阀处的流场,选用Lagrange颗粒轨道模型追踪硫颗粒在球阀处的运动轨迹,探讨影响硫颗粒在球阀处沉积的因素。结果表明:气流进入球阀内将会出现压力损失和流动分离,气流进口速度和球阀开度会对流场产生影响;硫颗粒在球阀处的沉积率随气流流速和颗粒直径的增大而增大,随球阀开度的增大而减小;重力和离心力是造成硫颗粒在球阀处出现大量沉积的重要原因。     

Transport of Sewage Sludge in a Mixed Water Column

Sewage sludge from four publicly-owned treatment works was sampled and characterized in terms of parameters affecting transport at the 106-mile deep ocean disposal site as part of the US Environmental Protection Agency's site monitoring programme. Samples from treatment plants in Passaic Valley, Rahway, and Elizabeth, New Jersey and New York City were characterized in terms of dynamic size distribution, suspended solids and density. the transport characteristics of sludge particles were measured using a 2 metre computer-interfaced laboratory settling column. Experiments were conducted at constant salinity (35 ppt) while varying hydrodynamic mixing, sludge type and concentration using a modified factorial experimental design. Hydrodynamic power dissipation was varied so that the vertical dispersion and rms fluid shear rate ranged between 0-6 cm²S^-1 and 0-30s^-1 respectively. Results indicate that at least 80% of suspended sludge particles will eventually settle under mixed conditions. the average settling velocities ranged between 0.05-4.05 × 10^-3 cm ^s-1. Shear rates above 15 s^-1 inhibited sludge settling due to aggregate breakup and boundary effects, but at a lower shear rate, differential settling and fluid shear were the dominant transport mechanisms. Sludge dilution (1/500-1/5000) had a limited effect on the settling rate. Results from this study can be used to calibrate particle transport models to determine the fate of sludge disposed at an ocean disposal site.     

On the Size Dependence of Particle Deposition

Measurements of dry deposition ofparticles 0.1 to 1.0 m diameter to forest bythroughfall and eddy correlation methods giveresults of 1.0 cm s^-1 or more, whilemechanistic models do not explain values greaterthan about 1 mm s^-1. Results of othermethods involving radioactive tracers arerecalled. These data indicate values of about 5 mm s^-1. The possibility of additionalmechanisms, omitted from the models, is difficultto exclude, but much of the remaining discrepancymay be due to the wide size distribution of theadventitious radioactive tracers in the atmosphere.     

珠江口水体组分的吸收特性分析

水体组分吸收特性是水下光场和水面光谱的主要影响因子,对其进行研究有助于提高对水体光学特性的认识和水质参数的遥感反演.基于2013年7月珠江口水体30个样本的实测数据,对珠江口水体总颗粒物、非藻类颗粒物、浮游藻类和CDOM的吸收特征进行了分析,结果表明:1总颗粒物吸收特征为非藻类颗粒物主导类型;2非藻类颗粒物的吸收系数遵循指数衰减规律,主要来源是陆源性输入,指数斜率Sd均值与空间变化幅度高于内陆二类水体;3多项式关系能较好地表达aph(440)与叶绿素a浓度的关系,而aph(675)与叶绿素a浓度存在很好的线性相关,辅助色素对浮游藻类吸收系数的影响主要在短波波段,长波波段叶绿素a的影响占主导地位,比吸收系数随叶绿素a浓度的增加而减小,呈现幂指数衰减规律;4CDOM输入以陆源为主,光谱曲线在紫外波段250~290 nm之间存在一个吸收肩,按光谱特征分段拟合Sg值能够更好地表达CDOM吸收特性,M值与A段(240~260 nm)的斜率Sg值呈现较强的正相关,珠江口水体的M值较小,CDOM中腐殖酸含量较高;5珠江口水体非色素颗粒物吸收在总吸收中占主导地位,浮游藻类吸收对总吸收的贡献远小于非色素颗粒物,CDOM吸收对总吸收的贡献最小,当CDOM中腐殖酸含量较高时,CDOM对水体总吸收的贡献大,腐殖酸含量较低时,CDOM对水体总吸收的贡献小.     

Chemical characteristics and source apportionment of atmospheric particles during heating period in Harbin, China

Atmospheric particles（total suspended particles（TSPs）; particulate matter（PM） with particle size below 10 μm, PM10; particulate matter with particle size below 2.5 μm, PM2.5）were collected and analyzed during heating and non-heating periods in Harbin. The sources of PM10 and PM2.5were identified by the chemical mass balance（CMB） receptor model.Results indicated that PM2.5/TSP was the most prevalent and PM2.5was the main component of PM210, while the presence of PM10–100was relatively weak. SO-4and NO-3concentrations were more significant than other ions during the heating period. As compared with the non-heating period, Mn, Ni, Pb, S, Si, Ti, Zn, As, Ba, Cd, Cr, Fe and K were relatively higher during the heating period. In particular, Mn, Ni, S, Si, Ti, Zn and As in PM2.5were obviously higher during the heating period. Organic carbon（OC） in the heating period was 2–5 times higher than in the non-heating period. Elemental carbon（EC） did not change much. OC/EC ratios were 8–11 during the heating period, which was much higher than in other Chinese cities（OC/EC： 4–6）. Results from the CMB indicated that 11 pollution sources were identified, of which traffic, coal combustion, secondary sulfate, secondary nitrate, and secondary organic carbon made the greatest contribution. Before the heating period, dust and petrochemical industry made a larger contribution. In the heating period, coal combustion and secondary sulfate were higher. After the heating period, dust and petrochemical industry were higher. Some hazardous components in PM2.5were higher than in PM10, because PM2.5has a higher ability to absorb toxic substances. Thus PM2.5pollution is more significant regarding human health effects in the heating period.     

空投装备着陆冲击环境适应性研究

目的研究空投着陆冲击环境适应性。方法采用有限元、响应面和蒙特卡罗方法,预测空投着陆成功概率;研究不同垂直着陆速度、地面坡度和地面风速对空投着陆成功概率的影响;分析空投装备着陆冲击环境适应性数据,提出提高空投装备着陆冲击环境适应性的措施。结果垂直速度和地面风速对综合成功概率影响显著,地面坡度的变化对综合成功概率的影响不显著。结论通过该方法,能够成功预测空投着陆成功概率,为空投实践提供理论依据和技术指导。     

大气细粒子阳离子表面有机活性物质分析方法的优化

分别从样品前处理和分析测定两方面对大气细粒子中阳离子表面有机活性物质的二硫蓝分光光度分析法进行优化,并采用优化方案对北京市大气细粒子进行了分析.结果表明:① 优化的最佳样品前处理条件中超声提取频率为40 Hz、初始水浴温度为30℃、超声提取时间为30 min;② 优化的最佳分析测定条件中二硫蓝使用量为1.29 mg（0.5 mL的2.58 g/L二硫蓝溶液）、最佳静置时间为30 min、醋酸盐缓冲液（pH为5）最佳使用量为3 mL.二硫蓝分光光度法优化方案标准曲线的R2为0.9986,线性较好.采用该优化方案测得的北京市大气细粒子中阳离子表面有机活性物质浓度的平均值为12.87 pmol/m3,其浓度水平数量级是阴离子表面有机活性物质的1/10,其浓度水平高于英国诺威奇与爱丁堡,但低于马来西亚吉隆坡.      

自贡市大气颗粒物污染特征及来源解析

利用自贡市大气监测数据、同期气象数据以及颗粒物源解析在线监测资料,对颗粒物污染的特征及成因进行研究.结果表明:颗粒物年均浓度受浮尘天气影响明显,季均浓度呈冬高夏低变化,月均浓度呈"U"字形变化,日均浓度呈双峰型变化;颗粒物与降水、温度、气压、风速存在相关性,与相对湿度无相关性,PM10、CO、NO2、SO2、O3浓度对PM2.5浓度变化影响显著;PM2.5主要成分为元素碳、有机碳、富钾颗粒等,主要来源为机动车尾气、燃煤、工业工艺源等.     

北偏西大风对北京冬季生物气溶胶的影响

生物气溶胶对大气成云过程、生态系统演化和人体健康都有着重要的影响,目前对生物气溶胶浓度、组成和活性的变化规律认识不足.因此,在2013年1月和2015年1月在北京市清华大学校园内进行了采样和观测,以分析气象条件对生物气溶胶浓度和组成的影响.生物气溶胶浓度用生物气溶胶在线检测器WIBS-4A(waveband integrated bioaerosol sensor)测定,生物气溶胶中细菌群落的组成用16S rDNA测序的方法来测定.结果表明,北京冬季生物气溶胶数浓度范围在2~150 L~(-1).风是影响生物气溶胶的浓度和组成的重要因素.主导风向为北偏西30°,风速大于4 m·s-1的大风天气时,生物气溶胶的数浓度升高1个数量级,生物气溶胶中细菌群落的组成也发生急剧的变化.大风天气过后,生物气溶胶中细菌群落的组成缓慢恢复到大风前的状态.