A comparison of manual handling risks in different domestic waste collection systems using three separate evaluation methods

Arising out of the challenge for Local Authorities (LAs) to operate sustainable systems of work, is to avoid the creation of ill-health including the most significant causes of physical absence, musculoskeletal disorders (MSDs).The study's aim was to compare the reliability of the manual handling element of the Health and Safety Executives (HSEs) risk comparator tool for different domestic waste collection methods with self-reported pain via body-mapping and MSD ill health absence rates. Participatory body-mapping exercises were carried out in five LAs with one LA resurveyed, six months after the move from 35 and 50 L containers to a wheeled bin recycling service.The lowest levels of self-reported pain were for services designed with 240l wheeled bins excluding glass; the highest levels were for services that included 100l of garden waste sacks and recycling boxes. Industry data supports previous laboratory studies showing wheeled bins to be associated with less MSD outcomes than boxes, baskets and sacks.Triangulation of data established a statistically significant correlation of 0.85 (Pearson) between average pain-count (APC) and the mean MSD absence rates, with a strong correlation of 0.77 (Spearman) between APC and risk rating. The correlation is moderate, 0.49 (Spearman) between MSD absence and risk rating, reflecting possible intervening variables and a low participation rate by LAs.The contribution of this study is to improve the design of sustainable waste collection strategies to minimise MSD associated absence. In the absence of reliable absence data, body mapping should be used as a proxy method of assessing MSD risk.     

井下短路电流幅相保护及实现方式

建立了三相对称短路电流与相角的关系，给出了确定幅相保护特性的新方法，提出了相行的幅相保护的实现方式。     

延长煤矿矿灯使用寿命的一种实用型电路设计

针对煤矿大多数矿灯没有防止由于过度充电和充电电流过大所引起的矿灯寿命缩短的保护性电路的现状 ,根据现场具体实际情况和需要 ,依据经济、可靠、操作方便的原则 ,采用通用型双运放 35 8或 2 5 8等器件 ,实现了实用型矿灯充电保护器的设计。     

一种消除VIENNA整流器输入电流过零畸变的SVPWM调制方法

分析了VIENNA整流器在低载波比应用中因电感压降不可忽略导致输入电流在过零点处发生畸变的原因,提出了一种使用输入电流辅助判断SVPWM大扇区的调制策略,以消除输入电流的过零畸变及降低输入电流的THD值;并针对实际工程应用中输入电流采样易受干扰的问题,提出一种软硬件相结合的滤波方法以提高扇区判断的精度。进一步,根据SVPWM电压利用率与调制比的关系,分析了输入电流辅助判断SVPWM大扇区方法的适用条件,得到使用该方法的输出电压边界条件。最后,使用MATLAB搭建了该整流器的仿真模型,并制作了一台1.5kW VIENNA整流器实验样机,仿真与实验均验证了所提出的改进型SVPWM调制方法的可行性,能有效消除输入电流的过零畸变。     

甲烷中四氢噻吩标准气体定值方法研究

甲烷中四氢噻吩标准气体是保证天然气中加臭剂准确分析的计量基础。采用感量为0.1mg的质量比较仪,使用称量法进行甲烷中四氢噻吩的称量并定值,同时对比了使用分压法制备,以氮中的H_2S为分析标准,使用总硫定值的方法。由于四氢噻吩与气瓶之间的作用,称量法的定值结果与实际样品中的四氢噻吩浓度存在偏差。而使用分压法制备,总硫定值的方法由于四氢噻吩与气瓶的作用达到平衡后进行定值,定值结果与其他机构研发的四氢噻吩标准气体之间的差值在标准物质不确定度接受范围内。分压法制备,总硫定值的方法可以作为较为适宜的甲烷中四氢噻吩定值研发方法。     

0.1 mg感量质量比较仪对标准气体称量不确定度的影响研究

通过对0.1mg感量的标准气体称量设备进行称量过程的不确定度来源进行探讨和量化,并使用标准方法进行称量结果不确定度的评估,得出使用0.1 mg感量质量比较仪进行标准气体称量时,单次称量的不确定度约为0.2mg。通过称样量的控制,最终获取的标准气体不确定度的原主要贡献源称量不确定度进一步降低,影响低于原料气纯度不确定度,甚至各组分摩尔质量的不确定度。使用0.1mg感量的标准气体称量设备进行标准气体称量时,标准气体的标准合成称量不确定度可低于0.02%以下。     

Uncertainty reducing method for the reference standards in gauge block comparator calibration

A simple method for reducing the uncertainty of reference standards has been proposed for gauge block comparator calibration. Errors due to the reference value of the length difference for mechanical comparator evaluation can be reduced by using the average of two reference values. Two reference values of length difference are obtained by the appropriate combination of three gauge blocks. Errors caused by reference gauges are canceled and averaged. An error reduction effect was successfully demonstrated using an actual mechanical comparator.     

一种CNFET的多位三值比较器设计

As the ternary comparator faces problems of slow speed and high power consumption, this paper proposes a scheme for the magnitude ternary comparator of CNFET, which is researching on theory of multi-valued logic circuit and the structure of comparator circuit. First, the ternary decode signal is propagated to the comparator, then the encoder circuit encodes the results of comparison, and finally the magnitude ternary comparator is made up of all kinds of modules. The magnitude comparator is simulated by software, which demonstrates that it has a correct logic function, fast speed and low power consumption characteristics.     

基于平衡态的动态比较器失调电压分析和设计优化

本文提出了一种基于平衡态的动态比较器失调电压分析设计技术。以两支路电压电流相等的平衡态为分析基础,通过在复位电压跳变时刻引入补偿电压的方法,逐一分析了动态比较器各晶体管参数对总体失调电压的影响,建立了失调电压的数学模型;采用Chartered 0.18um1P6M工艺对Lewis-Gray型动态比较器进行了电路和版图设计,并利用可快速提取失调电压的定步长仿真方法对其失调电压进行了仿真,结果表明所提出的分析方法可以相对准确的估算失调电压。以该分析方法为基础,本文还提出一种基于总体失调电压影响权重的晶体管分组优化方法,在保证总体面积不变的条件下,可将失调电压有效降低50%以上。经流片测试结果表明,本文所提出的分析和优化方法可应用于高速高精度系统中比较器的设计。     

Design and Optimization of Full Comparator Based on Quantum‐Dot Cellular Automata

Quantum‐dot cellular automata (QCA) is one of the few alternative computing platforms that has the potential to be a promising technology because of higher speed, smaller size, and lower power consumption in comparison with CMOS technology. This letter proposes an optimized full comparator for implementation in QCA. The proposed design is compared with previous works in terms of complexity, area, and delay. In comparison with the best previous full comparator, our design has 64% and 85% improvement in cell count and area, respectively. Also, it is implemented with only one clock cycle. The obtained results show that our full comparator is more efficient in terms of cell count, complexity, area, and delay compared to the previous designs. Therefore, this structure can be simply used in designing QCA‐based circuits.