The transfer of strontium-90 and caesium-137 to milk in a dairy herd grazing near a major nuclear installation

A field investigation of the transfer of artificially produced radionuclides in the pasture--cow--milk pathway has been made at a farm close to the nuclear fuel reprocessing installation at Sellafield on the north-west coast of England. This paper reports results from analyses of samples collected during 1981, reports transfers coefficients for 90Sr and 137Cs from various types of feed to milk, and discusses factors that affect the transfer of these radionuclides. It is shown that during 1981 a large proportion of the 90Sr and 137Cs consumed by cattle grazing near Sellafield was derived from activity deposited in previous years. Transfer coefficients to milk, Fm, have been derived which are within the ranges of those observed in tracer and fallout studies. There are significant seasonal changes in transfer. For 90Sr, values of Fm between 9 X 10(-4)d 1(-1) and 4 X 10(-3)d 1(-1) have been obtained. It is concluded that this large range arises because daily intakes of 90Sr by the herd during the winter months are lower (by a factor of about 3) than intakes during the summer months and that the concentration of 90Sr in milk is not in equilibrium with intake, that is, the concentration of 90Sr in milk is maintained both by recent intakes and by remobilisation of activity that has been accumulated in bone from earlier intakes. For 137Cs, values of Fm between 3 X 10(-3)d 1(-1) and 9 X 10(-3)d 1(-1) have been obtained. It is concluded that this range most probably occurs because during the summer months, when the cows are grazing, a substantial proportion of the 137Cs intake is associated with soil on the surface of herbage and that, in this form, the 137Cs is less available for uptake from the digestive tract of the cows.     

M310核电机组主管道安装工期分析及优化

以方家山核电站M310核电机组主管道安装为例,介绍了主管道焊接安装的方案,对主管道焊接工期进行了评估,分析了影响主管道焊接作业的主要因素,提出了焊接施工的注意事项以及工期优化措施。     

Chemical characteristics of airborne particulate matter near major roads and at background locations in Macao, China

PM10 and PM2.5 samples were collected near major roads and at the background locations in Macao using a TEOM1400a+ACCU system. The chemical analysis of these particles indicated the presence of 36 elements, water-soluble ions and carbonaceous species. The greatest contributors to total PM10 and PM2.5 mass were OC, sulfate, nitrate, ammonium, EC, Na, Cl and crustal elements including Si, Ca, Al, Fe, K and Mg. Organic material is the largest single fraction of airborne particulate matter in Macao. It contributes 32.8-41.5% and 38.2-48.4% of PM10 and PM2.5 at the roadsides, and as high as 29.7% and 33.4-39.4% of PM10 and PM2.5 at background locations, respectively. EC contributes 3.7-7.8% and 8.0-12.9% of PM10 and PM2.5, and crustal material is 10.2-15.4% and 7.6-12.2% of PM10 and PM2.5 near major roads, respectively. The share of EC at background locations is much lower than that at the roadsides, however, the contribution of crustal material is the same in both locations. At the roadsides, secondary aerosols, including sulfate, nitrate and ammonium, account for 16.6-29.0% and 15.8-38.0% of the total PM10 and PM2.5, respectively, as compared to 29.1-36.2% and 23.2-33.8% of total PM10 and PM2.5, respectively, at background locations. In PM2.5, Na and Cl contribute 1-3%, while the average amount of these two elements increase to 1-15% of the total PM10 in Macao.     

The positive use of power on a major construction project

Although reasonably well developed in the general management literature, the source and use of power in organizations has received little attention in relation to its effect on the management of construction projects. This paper reviews the literature on power and its relationship to both formal and informal authority, and its manifestation as organizational politics, and relates them to construction projects in general. Reward, coercive, expert and referent (prestige) power and the role of resources are covered in this general review. A closer examination is then made of power through a case study of the development of the Hong Kong University of Science and Technology, which identifies the positive use of power and its implications for the outcome of the project.     

Field studies on coliphages and coliforms as indicators of airborne animal viral contamination from wastewater treatment facilities

The occurrence of animal viruses in the aerosol emissions of wastewater treatment facilities was evaluated by direct assay and by the use of coliforms and coliphages as indicator organisms. Coliforms and coliphages were compared and evaluated with regard to their suitability as indicators of airborne animal viral contamination from wastewater treatment facilities. Two plants, one with treatment by activated sludge and the other by trickling filtration, were studied. Field air sampling procedures used large-volume air samplers, with recirculation devices, and Andersen samplers. Airborne viruses were enumerated by a most probable number (MPN) procedure. Partially treated liquid sewage contained about 1.0 × 10² pfu l⁻¹ of animal viruses assayed on Buffalo Green Monkey (BGM) cells, 3.6 × 10⁵ and 5.0 × 10⁵ pfu l⁻¹ of coliphages, depending upon the E. coli host strain used for assay, and 2.0 × 10⁹ colonies l⁻¹ of coliform bacteria. No airborne animal viruses were recovered, airborne coliphage levels averaged 2.3 × 10⁻¹ and 3.0 × 10⁻¹ MPN m⁻³, coliforms from aerosol emissions were 2.1 × 10² colonies m⁻³. Ratios of coliphages to animal viruses indicate that wastewater treatment plants may be continuous sources of low level concentrations of animal virus aerosols. Evidence shows coliforms to be much less stable than coliphages in the airborne state. Coliphages may be a more acceptable indicator of airborne animal viral contamination than coliforms.     

微波在线测湿仪的安装调试及应用

微波在线测湿仪在混凝土搅拌站中能对生产用砂进行连续在线测湿,从而实现生产中减水加砂的全自动控制,对稳定混凝土出厂坍落度效果理想。本文通过微波在线测湿仪的安装、调试及应用谈一点体会,以期提高测湿精度。     

简述核电汽轮机的安装

分析总结了核电汽轮机的安装,阐述了大型核电汽轮机在安装过程中的若干典型特点、所采取的特殊解决措施以及值得总结的典型安装施工经验,具有一定的参考价值.     

邻近及上跨铁路既有线金属幕墙安装施工

根据杭州南站站房金属垂直幕墙的施工条件,制定了金属垂直幕墙的总体安装方案,并阐述了外立面铝板、内立面铝圆管及幕墙百叶板的安装技术,既保证了行车与施工的安全性,又满足了设计和验收的要求。     

分段安装在钢结构安装中的应用

结合西安市雅致东方大酒店工程实例,分析了分段安装钢结构的难点,并从加工厂分段制作、满堂支架搭设、起重机械选型等方面,阐述了钢结构分段安装的施工技术,并提出了施工质量保证措施,为钢结构安装施工提供了思路。     

Changes in rainfall chemistry and airborne particulates during a period of major local industrial change

Data from a site in central Scotland were used to quantify the changes in rainfall quality from 1989 to 1998. During this period there have been major changes in industrial activities in the area, particularly the decline in local steel-making and steel-processing activities. Many element concentrations in rainfall decreased over time in parallel with the phased reduction in the activity of local pollutant sources. Trend analyses of the rainfall data identified that the most significant responses have been the lower concentrations of Ca, SO4-S and Mn. There was also a dramatic decline in the capture of airborne particulates by the interception rainfall gauges. Particulates were found to contain mainly hematite, magnetite and quartz, that is similar to what would be expected to be derived from the neighbouring steel industries. The eventual disappearance of these particulates and the responses in rainfall quality match the timescale for the decline and closure of some of the potential sources of pollutants.     

The use of light water for major aircraft fires

When a new extinguishing agent appears on the scene, existing agents become the yardsticks by which its performance is measured. The authors compared the relatively new Light Water foam with conventional protein foam and protein foam to which surface-active fluorocarbons had been added. Fire Research Station (JFRO) Note: Mr. Nash presented this paper at the 73rd Annual Meeting of the National Fire Protection Association on May 12, 1969 in New York City.     

Methods for processing aquatic mosses used as monitors of heavy metals

An evaluation is reported of methods used to prepare mosses for analysis when required for monitoring metal pollution. Fontinalis antipyretica and Rhynchostegium riparioides taken from the River Hoëgne, Belgium, were used for the study. The stages in preparation studied critically were the storage of the moss after it had been collected from the river, washing, choice of which particular fraction to use and the conditions for final drying prior to digestion. For any one particular treatment, the concentrations of metals analysed (Ca, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) were usually lower in Fontinalis than Rhynchostegium. Metal concentrations found as a result of the various treatments differed markedly for some metals, including Zn, Cd and Pb. However no one sequence of methods is ideal for all purposes. Criteria that need to be considered when selecting methods include the time and facilities available and whether the moss is to be used for monitoring long-term or short-term pollution.     

塔式起重机附着装置安装与使用管理思考

阐述了塔式起重机附着装置的安装方法,以及使用过程中出现的问题,并介绍了解决对策,论述了垂直运输起重机械在建筑施工现场安全生产的管理对策,保证了建筑施工安全进行。     

液压多斗挖掘机设计安装及使用维护的探讨

建材行业内使用液压多斗挖掘机的厂家不少,但设计制作的较少;为此就液压多斗挖掘机设计方面涉及的受力分析、设备安装条件、如何操作使用及设备完成的效果等方面问题进行讨论。     

浅谈门窗玻璃垫块的安装方法

本文简要介绍了门窗玻璃垫块在门窗组装中的作用及安装方法,避免因为玻璃重量分布不均而造成“掉角”等现象。     

Clothing as a transport vector for airborne particles: Chamber study

Strong evidence suggests that clothing serves as a reservoir of chemical pollutants and particles, including bioaerosols, which may have health significance. However, little is known about the role that clothing may play as a transport vector for inhaled airborne particles. Here, we contribute toward bridging the knowledge gap by conducting experiments to investigate clothing release fraction (CRF), determined as the size‐dependent ratio of released to deposited particulate matter in the diameter range 0.5‐10 μm. In a fully controlled chamber with low background particle levels, we deployed a programmable robot to reproducibly quantify the size‐dependent CRF as a function of motion type and intensity, dust loadings, and activity duration. On average, 0.3%‐3% of deposited particles were subsequently released with fabric motion, confirming that clothing can act as a vehicle for transporting airborne particles. The CRF increased with the vigor of movement and with dust loading. Rubbing and shaking the fabric were more effective than fabric stretching in resuspending particles. We also found that most of the release happened quickly after the onset of the resuspension activity. Particle size substantially influenced the CRF, with larger particles exhibiting higher values.     

建筑机电设备安装施工的主要环节及改进方法

分析了建筑机电设备安装施工的主要环节,从安装操作不恰当、过电流现象、连接出现松动三方面,对建筑机电设备安装施工存在的问题进行了阐述,并提出了相对应的改进方法。     

液压顶升平桥安装使用浅析

液压平桥是一种在电厂冷却塔施工中与多功能施工升降机配合使用的新型施工设备,本文介绍液压顶升平桥安装使用中,除按使用说明书操作外,需特别注意的一些注意事项。     

AP1000核岛安装工程通风保温防腐车间规划分析

根据AP1000核导安装工程通风保温防腐主要工作内容,从AP1000核岛安装工程通风保温防腐施工特点入手,对AP1000核岛安装工程通风保温防腐车间规划进行了分析,以期指导实践。