颗粒物再悬浮和检测系统的性能指标

系统地提出了颗粒物再悬浮和检测系统的性能指标,指标至少应包括5方面：颗粒物浓度稳定性、浓度调节平衡时间与连续运行时间、浓度可调范围、颗粒物采样均匀度、粒径分布的一致性. 根据干粉气动再分散方法和气溶胶力学理论,集成了一款颗粒物再悬浮和检测系统,并按照指标评估了该系统. 结果表明,浓度可调范围为0.1~12000 mg/m3,连续运行时间至少可达1~7 d,浓度调节平衡时间≤1 min;浓度稳定性较好,各种运行状态对应的浓度相对标准偏差(RSD)的平均值≤10%;各采样点采样均匀度好,RSD≤1.5%;混合箱内颗粒物在空气动力学直径0~40 mm范围内的粒径分布与待测粉尘一致.     

多通道PM2.5化学物种采样器的研制与应用

利用自行开发的设计计算软件,完成了PM2.5切割器特性尺寸的精确设计及其切割性能对喷嘴尺寸、采样流量和环境因素的敏感性分析.铝质切割器的切割粒径为2.42 μm,捕集的颗粒物质量浓度与"理想采样器"相差8.1%;采样系统的气密性良好,1 min内压力下降小于0.005 MPa;累积采样流量偏差小于±5%.实验室验证、与美国同类商业化采样器的平行采样对比以及在三个城市的现场运行均表明,研制的多通道PM2.5采样器的性能满足一次采样供质量浓度、化学物种及单颗粒特征等分析的实际应用需要.     

浅谈重量法测定固定源颗粒物中的常见问题

通过对现阶段我国测定固定污染源颗粒物方法的优劣比较,重点探讨了重量法测定固定源颗粒物中常见的问题,包括在采样时滤筒内液体附着、滤筒受环境破坏、滤筒口被污染、滤筒内有大颗粒、采样设备上颗粒物堆积,及称量时滤筒本身和称量过程的误差并对采样和称量环节遇到的问题逐一分析讨论,归纳总结解决问题的办法。最后对固定源颗粒物测定方法的改进提出了建议。     

大气颗粒物中多环芳烃的粒径分布

用GC/MS法测定了北京市北部的城乡结合部和远郊区的大气颗粒物中的16种优控多环芳烃(PAHs)的浓度。采样时间从2003年1月到11月,分季节采样。采样器采集的大气颗粒物粒径分为5段,粒径范围从小于等于1.1μm到100μm。对颗粒物中的总优控PAHs和检测出的单一优控PAHs在不同地区、不同时期的粒径分布进行了比较和讨论。总优控PAHs和单一优控PAHs化合物均趋向于吸附在小粒径颗粒物中,占总量47%~65%的总优控PAHs分布在粒径小于1.1μm的颗粒物中,只有不到10%的总优控PAHs分布在粒径大于7.0μm的粗颗粒物上。     

内蒙古自治区土壤及沙尘指纹特征之比较分析

探讨了内蒙古自治区内3个不同沙源区土壤再悬浮沙尘指纹特征,做为追踪与判断下风影响区域亚洲沙尘的依据,并以理清亚洲沙尘传输路径.于内蒙古自治区沙源地采集30个土壤样本,携回实验室重新悬浮后,以双粒径分道采样器(Dichotomous smpler)进行悬浮微粒(PM2.5及PM2.5-10)采样,再分析土壤及沙尘化学成分,分析项目包括水溶性离子成分、碳成分、金属元素成分等.化学成分分析结果显示,内蒙古自治区沙源地的指纹特征为(1)PM2.5-10/PM10＞0.74,(2)OC/EC＜1.0.本研究也发现人为污染物(如SO42-,NO33,NH4)也存在于沙尘微粒中.     

一种石油类地表水采样器的设计与应用

根据目前市售采样器在应用上的缺陷,设计了一款新型石油类地表水采样器(实用新型专利编号:CN204142522U)。介绍了其的研究背景、工作原理、结构组成。该采样器的主要有优点是操作简单,携带方便,定位准确。经试验证明,解决石油采样过程中定容问题和定点采样问题,利用卡扣原理解决快速放置采样瓶的问题,避免采样瓶因用力不均造成瓶体损坏。和传统的采样器在采样速度、采样效果进行比较,新型采样器都明显优于目前市售采样器。     

液氨分析采样器的设计与应用

针对传统液氨分析采样器存在的温度难达标、不安全、成本高、耗时长的问题，对采样器进行了重新设计。采用新设计的液氨采样器后，有效缩短了采样时间，实现可视化采样，保证了采样人员的安全，避免了环境污染，成功解决了传统采样中存在的问题。     

北京市大气颗粒物中多环芳烃的分布特征

用撞击式分级采样器同步采集了北京市城乡结合部、郊区的2003年4个季节的不同粒径大气颗粒物样品，用气相色谱-质谱分析了其中的多环芳烃，并对两个地区大气颗粒物中的多环片烃含量、分布及季节性变化特征进行了探讨。     

黄石市工业边缘区大气中重金属浓度及化学特征

目前大气环境的污染相当严重，大气颗粒物是大气污染的首要因素，而对重金属的分析已经成为研究热点。重金属对大气环境的危害，将主要取决于颗粒物中重金属的含量，因此对大气颗粒物中重金属的含量检测具有非常重要的意义。本研究在湖北省黄石市工业边缘区设置PM₁₀大流量采样器，进行连续周期采样，以采样点所采集的可吸入颗粒物PM₁₀为样本和研究对象，对其中含有的活性重金属(Pb、Cu、Cd、Cr、Zn)进行浓度检测，将检测所得的数据进行相关统计分析，并结合相关文献数据的研究，对黄石市大气环境进行初步评价。     

一种新型地表水石油类采样器的设计应用

设计了一种新型地表水石油类采样器,通过浮球及线距拉动活塞控制采样深度,排气管气水分流控制采样体积,可有效避开表层浮油,实现定深下自动采样、自动定容,样品无须二次转移.该设备结构简单,安装便捷,方便使用,实现了各种水环境任意水深层次的样品采集,满足地表水石油类采样规范要求,该采样器亦可用于研究水体不同层次的水质状况和变化...     

Sampling

Conclusion It is hoped that the foregoing general remarks on sampling procedures will point up the necessity for more care in this very important operation. In too many instances sampling has been delegated to persons not too well aware of the purpose and importance of the samples which they are taking, and possibly not too well qualified to handle the job. This situation could be improved markedly by better training and instruction of persons delegated to take samples, or preferably by selecting persons better qualified and more interested in this essential but rather non-glamorous operation. There is also the need for better equipment specifically designed to handle the more difficult and troublesome sampling situations, some of which have been mentioned previously. Much unnecessary work on the part of the analyst could be eliminated, and at the same time his prestige could be raised materially, if the samples he received for analysis were always true and representative parts or segments of the entire lot of material on which his evaluation is based.     

煤化工分析取样及典型取样方法设计

本文阐述了分析取样是所有分析检测工作开展前必须进行的重要环节,明确分析取样必须遵循的原则及注意的安全事项,对分析取样方法和取样系统设计给出具体的实践性指导。文章结合具体的工程设计实例,阐述了煤化工分析取样要达到安全、有效、准确所需的技术措施,并以详实的图示介绍了相关工程设计中的典型分析取样系统的设计。     

Meal and Grain Sampling

A short history of grain sampling is given and the recent U.S. Grain Standards Act. per U.S.D.A. publi-cation of 1968, is reviewed briefly. Inspection tech-nique depends on the type of sample being used: official sample, type sample or warehouseman’s sample. Terms, such as, permissive inspection and exception, are explained. Mechanical grain and meal sampling methods and the equipment used are dis-cussed. A close look is given to their practical application and the mathematics of operation. Facts that point to the future of sampling are given. One of four papers being published from the Symposium “Sampling and Process Control in the Oilseed Industry,” presented at the AOCS Meeting, New Orleans, April 1970.     

Sampling soybeans for analysis

Conclusion Under the conditions of this study, 30-gram samplings of mixtures of soybeans were found to differ significantly in oil and nitrogen content indicating the desirability of larger samples. The use of 120 to 240-gram aliquots from mixtures of soybeans which vary widely in chemical composition should tend to reduce differences due to sampling to a reasonable minimum. Differences among 30-gram samplings of highly uniform soybean seed of a single variety seem to be of slight significance. The limitations of present sampling methods should be recognized in any comparison or interpretation of chemical analyses of soybean seed. The U. S. Regional Soybean Laboratory is a cooperative organization participated in by the Bureau of Plant Industry, Soils, and Agricultural Engineering, Agricultural Research Administration, U. S. Department of Agriculture and the Agricultural Experiment Stations of Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Louisiana, Michigan, Minnesota, Mississippi, Missouri, Nebraska, North Carolina, North Dakota, Ohio, Oklahoma, South Carolina, South Dakota, Tennessee, Texas, Virginia, and Wisconsin. Assistant Chemists and Assistant Scientific Aide, respectively, U. S. Regional Soybean Laboratory, Urbana, Illinois.     

优选采样机是保证出口煤采样精确度的关键

阐述了对出口煤采样工作的重要性,介绍了适合于中国外贸出口用的一些进口采样机的基本特性。     

Field Evaluation of Sampling Bias with Plastic Petri Dishes for Size-Fractionated Bioaerosol Sampling

Reusable glass dishes are recommended for use with the six-stage viable impactor for size-fractionated bioaerosol sampling. However, it is not convenient to use glass dishes because they are fragile and heavy, not to mention the time-consuming preparation process prior to bioaerosol sampling. On the other hand, disposable plastic dishes have been widely used in microbiology laboratories. However, plastic materials can retain electrostatic charges and may lead to sampling bias. The objective of this study was to evaluate the sampling bias with the use of plastic dishes when a multistage viable impactor is used for airborne fungi and bacteria sampling for field sampling. Two six-stage viable impactors were placed side-by-side 1 m apart in a 147-m³ room. One was used with plastic dishes and the other with glass dishes. Compared with the concentration data obtained with glass dishes, those collected with the plastic dishes demonstrated a significant difference for both fungi and bacteria. However, there was a strong correlation between the data obtained using glass and plastic dishes, which can be estimated by C_plastic = 0.88 C_glass for airborne fungi and C_plastic = 0.86 C_glass for airborne bacteria. When using plastic dishes fungi and bacteria counts were underestimated by 12% and 14%, respectively.

Copyright 2015 American Association for Aerosol Research     

Stratospheric Aerosol Sampling: Effect of a Blunt-Body Housing on Inlet Sampling Characteristics

During a campaign to study ozone loss mechanisms in the Arctic stratosphere (SOLVE), several instruments on NASA's ER-2 aircraft observed a very low number density (0.1 I^?1) of large, nitric-acid-containing particles that form the polar stratospheric clouds (PSCs). For effective physical and chemical characterization of these particles, the measurements from these instruments have to be intercompared and integrated. In particular, proper interpretation requires knowledge of the sampling characteristics of the particles into the instruments. Here, we present the calculation of the sampling characteristics of the one of the instruments on the ER-2, the NOAA NOy instrument. This instrument sampled ambient particles and gas from two forward-facing inlets located fore and aft on a particle-separation housing (the football) and measured total NOy in the sample. In recent studies, ambient aerosol mass has been estimated by the difference of the measurements of the two inlets with the assumption that the rear inlet observations represent the gas-phase NOy and small particles and the front inlet samples represent gas-phase NOy and all particle sizes with varied efficiency (anisokinetic sampling). This knowledge was derived largely from semiempirical relations and potential flow studies of the housing. In our study, we used CFD simulations to model the compressible flow conditions and considered noncontinuum effects in calculating particle trajectories. Our simulations show that the blunt body housing the inlets has a strong and complex interaction with the flow and particles sampled by the two inlets. The simulations show that the front inlet characteristics are influenced by the effect of the blunt body on the upstream pressure field. The rear inlet sampling characteristics are influenced both by the shape and size of the inlet and its location on the blunt body. These interactions result in calculated inlet characteristics that are significantly different from previously assumed values. Analysis of the SOLVE data, considering the ambient conditions and the calculated inlet sampling characteristics, in conjunction with thermodynamic growth modeling of super-cooled ternary solution (STS) particles, provides validation of the CFD results.     

Possible Sampling Artifact in Real Time Particle Size Distributions Related to Sampling Rate

The availability of high time-resolution (1 s full spectrum scan) particle sizers permitted atmospheric researchers to scrutinize the characteristics of ultrafine particles in rapidly varying (perhaps, random) high concentration environments such as roadside, on-road, and tunnels. These data also revealed possible artifacts associated with the slower (～ 30 s or more) scanning sizers when used in this kind of environment. This study discusses sampling rate artifact problems based on simulations using 1 s Engine Exhaust Particle Sizer data taken on a mobile platform.     

Sampling for respirable cotton dust

The nature of sampling from a dust cloud containing fine dust and lint fragments is reviewed. The definition of “respirable cotton dust” in the OSHA Cotton Dust Standard is compared and contrasted with the quantity measured by the NIOSH (Lumsden-Lynch) vertical elutriator (VE) cotton dust sampler. Theoretical and empirical factors that affect the accuracy and precision of VE measurements are discussed. Technologies for alternative sampling strategies and for improving VE sampling are described. Presented at the Cotton Dust Symposium of the American Oil Chemists’ Society Meeting on May 17–21, 1981, New Orleans, Louisana.