A shell-based magnetic field model for magnetic proximity detection systems

Several magnetic proximity detection systems have been developed for mining vehicles and mobile machinery to protect nearby workers. Magnetic field generators are often used in these systems to establish magnetic fields around the equipment. A sensor worn by a worker provides a measurement of the magnetic flux density that is used to estimate the proximity to the machine. The proximity detection systems currently available for underground mining equipment are capable of identifying whether a worker is near the machine. However, it is a challenge for these systems to accurately locate the worker. Mining machines, which have fast-moving, articulated parts, present hazards that change depending on the situation at hand as well as the specific location of the worker. In addition, the dynamic nature and confined spaces of the mining environment often demand that the workers be close to the machinery. Therefore, in many cases, simply knowing the proximity of a worker may be inadequate. To provide the most effective protection, it would be advantageous to know the worker’s exact location relative to specific parts of the machine. To lay the foundation for measuring such a location, we have developed a shell-based model of the magnetic flux density distribution for a ferrite-cored generator. This paper will present an analysis of the model along with a model construction process. Also presented are the laboratory test results of a prototype system that implements this model to determine the exact location of a magnetic sensor using the fields from two generators.     

某选矿厂皮带通廊胶带机钢桁架检测及处理

对某矿业公司选矿厂磨矿仓皮带通廊胶带机钢珩架进行检测鉴定,查出结构的隐患,找出产生隐患的根源,提出加固处理力’案并进行处理。     

毛细管电泳间接紫外检测自来水中金属离子

介绍了毛细管电泳间接紫外检测技术,并对大连市自来水中Ca2 、 Na 和Mg2 质量浓度进行了测定,结果分别为(59.4±5.6) mg/L、 (21.0±0.1) mg/L和(18.6±0.7) mg/L,最低检测限依次为0.01 mg/L、0.04 mg/L和0.02 mg/L.实验条件为:石英毛细管柱50 μm(i.d.)×50 cm;运行电压16 kV( →-);紫外检测波长214 nm;缓冲液为pH=4.75的乙酸溶液,含有浓度为8.0 mmol/L的背景吸收物质咪唑;采用虹吸进样法,高度差为9.8 cm, 进样时间为10 s;应用内标法对Ca2 、Na 和Mg2 3种离子进行定性和定量测定.采用火焰原子吸收光谱法(AAS)测得Ca2 的质量浓度为54 mg/L,验证了毛细管电泳法实验结果的可靠性.     

海上简易平台安全检测的工作内容及应用

针对海上简易平台投产时间较长、受强外力影响因素较多等情况,以CB25A平台为例,介绍了海上简易平台的安全检测工作内容及安全生产注意事项.     

Roadside Measurements of Deforestation in the Amazon Area of Bolivia

This study describes the deforestation impact from three settlements, 5 de Junio, El Tigre, and 30 de Agosto, near the Madidi National Park in Bolivia. First deforestation rates along the road that connects the settlements and then deforestation within each settlement are examined. Landsat Thematic Mapper (TM) imagery from 1987, 1997, and 2000 were used to measure the deforestation. Face-to-face interviews were also used to collect detailed social and land-use information. Road-building and farming have been the major causes of deforestation in this region. The TM measurements indicate a high increase in the deforestation rate along the road in the area of study. The results also show a rapidly escalating deforestation rate in 5 de Junio, a potential high future deforestation rate in El Tigre, and a gradual deforestation increase in 30 de Agosto. The information provided by the settlers about clearing was compared with the imagery analysis. Generally, the settlers estimates were lower than the deforestation as derived from the imagery.     

气象雷达新技术及其在防灾减灾中的应用

新型气象雷达在国外越来越多地应用于大型外场试验和业务探测网中,我国也将在灾害性天气监测网中引入新型气象雷达。简要介绍了气象雷达的发展历史和国内外发展现状,阐述了气象雷达探测新技术,包括双线偏振雷达、双(多)基地雷达、相控阵天气雷达技术、激光天气雷达技术、风廓线雷达等的探测原理及其在气象中的应用,这对于我国新型雷达的应用和根据实际需求选择雷达类型等具有一定的指导和借鉴意义。     

An integrated off-on line approach for increasing stability and effectiveness of automated controlled systems based on pump dependability—case study: Offshore industry

Automated controlled systems are vulnerable to faults. Faults can be amplified by the closed loop control systems and they can develop into malfunction of the loop. A control loop failure will easily cause production stop or malfunction at a petrochemical plant. A way to achieve a stable and effective automated system is to enhance equipment dependability. This paper presents a standard methodology for the analysis and improvement of pump performance to enhance total operational effectiveness and stability in offshore industry based on dependability. Furthermore, it is shown how a reliability–safety analysis can be conducted through equipment dependability indicators to facilitate the mitigation of hazard frequency in a plant. The main idea is to employ principle component analysis (PCA) and importance analysis (IA) to provide insight on the pumps performance. The pumps of offshore industries are considered according to OREDA classification. The approach identifies the critical pump and their fault through which the major hazards could initiate in the process. At first PCA is used for assessing the performance of the pumps and ranking them. IA is then performed for the worst pump which could have most impact on the overall system effectiveness to classify their components based on the component criticality measures (CCM). The analysis of the classified components can ferret out the leading causes and common-cause events to pave a way toward improving pump performance through design optimization and online fault detection which ultimately enhance overall operational effectiveness.     

图像识别技术及其在机械零件无损检测中的应用

无损检测法是一种常用的故障诊断技术,故障诊断从本质上来讲就是模式识别问题,而模式识别又可以狭义地理解为图像识别。从介绍图像、图像识别、图像识别过程和图像识别系统的基本概念着手,就几种常用图像识别方法的原理和特点进行比较,给出了CCD图像获取系统的组成。最后,结合发动机曲轴的一种自动磁粉探伤系统实例,对系统的图像处理和识别流程进行详细的讨论,并针对一般无损检测系统难以满足曲轴的检测要求和精度要求的状况,提出经过改进的一种适用于曲轴的整体无损检测系统。该系统有助于高效和完整地获取整个曲轴的图像,提高图像信息的质量,从而提高发动机曲轴表面缺陷检测的准确性和可靠性。     

泄漏检测与修复(LDAR)检测数据准确性评估方法研究

泄漏检测与修复技术(LDAR)是控制石化企业设备与管线泄漏的最佳可行技术,检测数据准确度对于企业核算VOCs排放量及环境保护主管部门进行VOCs排污费征收和排污许可证管理至关重要.针对中国石化企业工艺装置特点和LDAR检测数据特征,设计了一套LDAR检测数据准确性评估方法,并运用该方法对24套石化装置的LDAR检测数据准确性进行抽测评估.结果表明该方法可以直观反映企业LDAR检测数据准确度,客观体现不同企业、不同装置在LDAR检测管理水平上的差异.