微生物学检验中菌落总数测量结果不确定度的评定研究

文章主要分析了微生物学检验中菌落总数测量不确定度的数学模型、测量不确定度的来源分析、测量不确定度的计算以及相应的表示方法.微生物学检验中菌落总数的测定,其特点是同一样品测定结果相差极大,由随机效应带来的测量重复性所导致的不确定度占了主要部分.通常的做法是对同一样品作多次测量,取对数后进行计算.     

Slip Resistance of Industrial Floor Surfaces: Development of an Elastomer Suited to In-Situ Measurement

Slips contribute to 12% of occupational accidents. A slip resistant floor is a mean to prevent slipping accidents occurring in workshops. Floor slip resistance is often evaluated by measuring a friction index, proportional to the force opposing slipping of a reference elastomer on the floor surface under test. When implementing a portable appliance, slip resistance measurements carried out on lubricated floors were not stabilized. The authors advanced the hypothesis of oil impregnating the elastomer. A new elastomer suited to in-situ measurement has been developed to achieve stable measuring conditions. This study highlights the fact that the nature and characteristics of a reference elastomer must be specified when slip resistance measurements are carried out.     

Locking of Retractable Type Fall Arresters—Test Method and Stand

Retractable type fall arresters are very effective personal equipment protecting against falls from a height. These devices are used under different atmospheric conditions and in the presence of various types of industrial pollution. For this reason appropriate locking after conditioning simulating extreme conditions of a worksite is one of the essential characteristics of retractable type fall arresters. This article presents the requirements for locking of the devices. A previously used locking test method and its disadvantages are discussed. The article suggests an improved test method and test equipment. Measurement of the test mass acceleration is the most important improvement introduced into the test method. The article shows laboratory tests used to verify the method, which turned out to be a valuable source of information concerning the performance of retractable type fall arresters.     

低粉尘浓度气体中细颗粒物（PM2.5）含量的测量

低粉尘浓度气体中细颗粒物（PM2.5）的测量用称重法和计数法都有困难,文章提出用稀释气体降低含尘浓度后,用激光尘埃计数器测量其中细颗粒物的数量,计算出质量浓度的办法。     

Calculating ecological footprints at the municipal level: what is a reasonable approach for Canada?

No clear ecological footprint calculation strategy is available for small- and mid-sized communities within Canada. By adjusting provincial or national footprint findings using data sets available in the public domain, we develop and test a calculation strategy to estimate municipal ecological footprints. Because the calculation approach is consistent with the Global Footprint Network standardised methodology, it permits meaningful comparisons between communities and with global and national footprint estimates. It offers planners, policy-makers, and community leaders an accessible, straight forward, and cost effective strategy for estimating the ecological footprint at the community and municipal level. The suggested approach is best suited for using the ecological footprint as an awareness and education tool. The large number of limitations associated with calculating the municipal approach and limitations associated with calculating ecological footprints in general at the local level make it an unsuitable tool to inform community planning and policy development.     

基于红外吸收法的哈龙替代灭火剂HFC－125的浓度监测技术

HFC-125(五氟乙烷)有较好性能,可替代哈龙灭火剂应用于飞机灭火系统中。在飞机灭火系统的评估实验中,模拟地面或是飞行状态,灭火剂浓度测量设备都是必不可少的。基于非色散红外光谱技术(NDIR),初步设计了HFC-125灭火剂浓度监测设备,该设备采用硅碳红外光源,入射光经过斩波器调制转变为交变光,通过单光路测量气室后,被碲镉汞红外探测器转化为电压信号并被前置放大电路放大。通过电压比与体积分数的对应关系,可以实现对HFC-125浓度的监测。     

铁路边界噪声限值测量中若干问题的讨论

阐述了铁路边界噪声测量中所遇到的问题主要有,铁路边界的界定,背景噪声的修正和测点距轨面相对高度、测点与轨道的地面状况,并对铁路噪声预测模式进行了对比分析,以及如何测量等实际问题提出了解决办法。     

下沉式地铁车辆段环境噪声特性试验研究*

针对下沉式地铁车辆段环境噪声问题,采用问卷调查与现场实测相结合的方法,对下沉式地铁车辆段环境噪声特性开展研究。结果表明:通风噪声是下沉式地铁车辆段主要噪声源,其次为列车噪声;办公区域噪声强度超出标准限值3~5 dB（A）,其中1 000 Hz左右中频段噪声带给人的烦恼度最高;检修库内存在严重低频噪声,尽管各测点均未超过标准限值,但由于风机长期24 h运行,仍会引起员工不舒适感;上盖司机公寓内二次结构噪声强度不满足环境标准限值要求,对公寓居民睡眠产生不良影响;结构振动噪声具有明显的低频特征,主要对16~250 Hz起作用,其中250 Hz频段超标最严重。     

浅谈在用工业管道的壁厚测定

某企业的在用压力管道发生爆裂事故,经事故调查组现场调查分析主要原因是管道壁厚减薄,承受不了内部正常工作压力所致。本文根据分析结果,提出了开展日常在线定点测厚、年度检查测厚和定期检验测厚的处理措施,预防此类事故的再次发生。     

基于时空分布特征的煤层瓦斯测压准确性研究

为获得真实可靠的现场实测煤层瓦斯压力,实现煤层突出灾害等级科学评价和精准防治,通过理论分析、数值模拟和现场验证相结合的方法,以双重孔隙介质为基础,根据煤层瓦斯流动模型和瓦斯压力恢复曲线,分析煤层瓦斯压力测定的时空分布及准确性,并以桃园煤矿Ⅱ1采区10煤层为例,开展工程验证。研究结果表明:当基质瓦斯压力与裂隙瓦斯压力处于动态平衡时,所测得的煤层瓦斯压力最为准确;所构建的用于COMSOL解算的煤层测压瓦斯流动方程,可实现瓦斯压力时空分布的准确模拟;当煤层实测瓦斯压力恢复曲线与模拟分布特征一致且处于工程预测值范围内,可以判定结果为真实值;现场工程验证了实测瓦斯压力恢复曲线与模拟结果一致,测压结果准确。