煤中全硫测定仪示值误差不确定度的评定

正煤中全硫测定仪用于煤和焦炭中全硫的分析。用煤样在高温下的空气流或氧气流中燃烧,其中各种形态硫都氧化或分解为二氧化硫和少量三氧化硫。据JJG1006-2005《煤中全硫测定仪检定规程》可知,煤中全硫测定仪划分为高温燃烧库仑测硫仪、高温燃烧红外测硫仪、高温燃烧中和法测硫仪。按照经验,工作中最常用的是高温燃烧库仑测硫仪,以下是其不确定度     

煤中全硫测定仪检定过程中常见问题解析

一、工作原理以目前使用最多的高温燃烧库仑测硫仪(以下简称"测硫仪")为例,生成的二氧化硫进入含有碘化钾和溴化钾溶液的电解池中,被电解生成的碘或溴滴定,根据滴定所消耗的电量,并对由少量三氧化硫不被滴定而导致的系统误差进行校正后,计算出煤中全硫的含量。二、仪器测量结果的影响因素在检定煤中全硫测定仪时,会出现测量结果不稳定、重复性测量结果不好。现针对这种情况提出几点     

煤质检验工作手记

任何煤中均含有硫,只是其含量有所不同,低则0．3％～0．5％,高则3％～5％。随着经济的快速发展,我国因燃煤排放的二氧化硫急剧增加,由二氧化硫引起的酸雨污染范围不断扩大,北京地区同样面临这样的污染,特别是2008年的奥运会期间,奥组委对北京空气质量的要求非常高。酸雨和二氧化硫污染危害居民健康、腐蚀建筑材料、破坏生态系统,造成了巨大经济损失,是制约社会经济发展的重要因素。     

红外测硫技术及在煤炭行业中的应用

1　引　言由于煤中所含硫的原因 ,在燃烧过程中会产生二氧化硫等硫的氧化物 ,如与空气中的水汽结合会形成硫酸蒸汽 ,并会在低温界面上凝结 ,严重污染和腐蚀设备 ,而且二氧化硫排放到大气中 ,不仅影响人的健康而且会形成光学烟雾和酸雨 ,严重影响和损害生态环境。因此燃煤含硫量的高低是电厂进煤的依据 ,也是国家监控ＳＯ2 排放的基本参数。2　原理简介红外测硫主要是根据红外光谱分析的原理 ,对煤样中的含硫量进行测试 ,该系统由三大部分组成 :高温燃烧系统、红外检测系统、计算机采集与控制系统。红外检测器是根据比耳定律 (式 1)将二氧化…     

超前地质钻孔对矿井安全的作用

随着矿井开采深度逐步延伸，井田内煤层厚度不稳，煤层倾角变化大，煤质松软破碎，煤与瓦斯突出、有毒有害气体腐蚀，水害，火灾，煤尘超标，顶板支护薄弱等等。必须打超前钻孔，进行抽放、探放瓦斯、稀释CO等有毒有害气体，探放水，煤岩体注水、穿层超前预支护．本文结合鹤煤八矿的具体地质情况对相关问题进行了研究探讨，实践证明可大大提高了煤矿安全生产水平。有效预防了矿井灾害的发生     

国外兵器包装的发展趋势

兵器包装必须满足运输、储存和方便部队使用的基本要求。在兵器运输和储存中,必须防止水、水蒸汽、氧、空气中携带的二氧化硫和盐粉等有害物、风、尘、紫外线、霉菌和昆虫等的腐蚀和侵害。电子产品、     

谢林台区煤质特征分析

谢林台区位于辽宁省彰武县西北部,内蒙古科尔沁沙地南缘的西北部,行政隶属彰武县大冷乡管辖。该区含煤地层为白垩系下统沙海组,根据区内可采煤层1-2、2-2化验资料,认为煤层属富灰、中硫至富硫、低有害成分、中低~中热值长焰煤。依据煤类和煤质特征该区煤可用于发电用煤,动力用煤及民用煤。     

球墨铸铁煤气管道泄漏原因分析

通过宏观和微观分析等手段,对某QT400-18球墨铸铁煤气管道泄漏原因进行了分析。由宏观分析可知管道腐蚀泄漏是由局部腐蚀穿孔所致,腐蚀从内壁开始,由内向外直至穿孔泄漏;微观分析没有观察到微裂纹等缺陷,成分分析可知管道内壁腐蚀产物中含有大量硫元素,说明管道腐蚀泄漏的产生与管内介质中含有硫元素有关。综合分析结果表明:由于所输送煤气中含硫杂质超标,与管内壁冷凝水共同作用产生局部电化学腐蚀,从而导致了煤气管道的局部穿孔泄漏。建议在生产中将煤气中的有害杂质和水分含量控制在工艺要求范围内。     

火焰光度法测定二氧化碳中总硫、非二氧化硫总硫技术研究

针对总硫、非二氧化硫总硫直接测定,采用火焰光度法对总硫分析进行了系统的研究,非二氧化硫总硫的无基体分离直接测定技术准确、可靠;同时,可以快速实现二氧化硫含量的间接测定。     

紫外荧光法在测定食品添加剂二氧化碳中总硫的应用

为了准确测得食品添加剂二氧化碳中总硫的含量,使用元素分析仪对二氧化碳中总硫的测定进行研究。采用紫外荧光检测器,样品中有机硫化物燃烧生成二氧化硫,二氧化硫在紫外灯的照射下形成激发态的二氧化硫分子,二氧化硫从激发态返回到基态放出一定的光,通过测定光的强度来测定总硫。     

Gender differences in publication productivity in psychology in India

An analysis of gender differences in psychology in India provides quantitative and qualitative assessment of R&D output contributed by psychologists with the indication of the trend of growth, skewness, relatedness, co-authorship pattern of productivity.     

Metrology in Chemistry in Germany

The system for Metrology in Chemistry in Germany is described. At the national standards level, a network of high-level chemistry institutes coordinated by the national metrology institute, PTB, provides the primary references for chemical measurements. A dissemination mechanism employs chemical calibration laboratories accredited within the framework of the German Calibration Service (DKD). They act as “multipliers” between the national standards level and the user level by providing the user with calibration means which are traceable to the SI via national standards. Traceability structures in clinical chemistry, electrochemistry, elemental analysis and gas analysis are described     

Natural radioactivity in drinking water in private wells in Finland

Natural radioactivity in drinking water was determined in population-based random study of 472 private wells. The mean concentrations of (222)Rn, (226)Ra, (234)U, (238)U, (210)Pb and (210)Po in drilled wells were 460, 0.05, 0.35, 0.26, 0.04 and 0.05 Bq l(-1), and in wells dug in the soil were 50, 0.016, 0.02, 0.015, 0.013 and 0.007 Bq l(-1), respectively. Approximately 10% of the drilled wells exceeded a radon concentration of 1000 Bq l(-1) and 18% a uranium concentration of 15 microg l(-1). The mean annual effective dose from natural radionuclides for a drilled well user was 0.4 mSv and 0.05 mSv for a user of a well dug in the soil. The effective dose arising from (222)Rn was 75% of the total of all natural radionuclides for drilled well users. As regards long-lived radionuclides, (210)Po and (210)Pb caused the largest portion of the effective dose. The dose arising from (238)U, (234)U and (226)Ra was only 8% of the total of all natural radionuclides.     

Natural radioactivity in drinking water in private wells in Finland

Radiation Protection Dosimetry     

Optische in situ Schichtdickenmessung in Bedampfungsanlagen. Optical in situ film thickness monitoring in coating systems

Optical film thickness monitoring is more precise than crystal monitoring. The optical measurement makes use of the fact that the intensity of a monochromatic light beam which is reflected on a film will change periodically with increasing film thickness. The measurement is performed at an exchangeable test glass that is positioned beside the substrates and is therefore coated in the same way as the substrates. The accuracy of cut‐off is achieved by a “fit” of a theoretical curve shape to the measured values. Order filters are used to ensure that, at a certain wavelength, higher deflection orders do not influence the measurement when a monochromator grating is used.     

Spanish experience in education and training in radiation protection in medicine

In most of its publications, the International Commission on Radiological Protection has highlighted the importance of education and training in radiation protection (RP) for medical exposures. Spain, like other Member States of the European Union, has implemented the Directive and the Guidelines in the medical area. The purpose of this paper is to present the Spanish experience in RP education and training in medicine, the different objectives established according to professional levels, existing regulations and feedback obtained from various RP actions.     

Differences in coagulation in clotting of vascular access in hemodialysis patients

Arteriovenous graft (AVG) thrombosis is a frequent cause of graft failure. We evaluated coagulation protein concentrations, platelet function, and viscoelasticity factors in 20 hemodialysis (HD) patients with AVGs. The goal was to determine whether significant differences in protein concentrations, platelet function, and viscoelasticity factors exist among dialysis patients requiring frequent AVG declot procedures vs. those who do not. Twenty HD patients were enrolled: 10 frequent clotters (>3 declots in the previous year) and 10 were nonclotters. Patients on antiplatelets or chronic anticoagulation were excluded. Laboratories were drawn pretreatment and heparinase was added to counteract any potential heparin effect. Coagulation protein concentrations including tissue factor (TF), thrombin/antithrombin III complex (TAT), and prothrombin fragment 1 + 2 (F₁₊₂) were assayed. The time to clot onset was measured by force onset time (FOT). Platelet contractile force (PCF) measured the force produced by platelets during clot retraction, whereas clot rigidity was measured as clot elastic modulus (CEM). FOT, CEM, and PCF were measured by Hemodyne. Both groups had upregulation of the TF pathway, as TF, TAT, and F₁₊₂ levels were similarly increased over baseline levels. Hemodialysis patients with frequent AVG clotting had higher levels of both PCF and CEM compared with nonclotters. Additionally, the frequent clotters had a lower FOT relative to nonclotters, although both were considered in the normal range. Our study suggests that HD patients with recurrent AVG thrombotic events form clots with higher tensile strength compared with HD patients without recurrent graft thrombosis.