Effects of falling weight impact on industrial safety helmets used in conjunction with eye and face protection devices

Industrial workplaces pose concurrent hazards to the upper part of the head and the eyes. Under the circumstances, workers may use protective helmets in conjunction with protective goggles or spectacles. In order to assess the compatibility of this equipment, a method and a test stand for evaluating the behavior of safety helmets and protective goggles/spectacles upon the impact of a falling weight were designed. The results of tests concerning the displacement and deformation of helmets and spectacles/goggles, the forces acting on the helmets, as well as the forces exerted by the spectacles/goggles on the headform upon falling weight impact are presented. The results revealed the ways in which the tested equipment interacted with each other. The influence of equipment construction on the test results was analyzed and inferences concerning the safety of the studied protective devices were made. Some general construction guidelines were formulated for the compatibility of the equipment.     

阿什河底栖动物群落特征及影响因子

阿什河作为松花江的一级支流,全境包含了从Ⅰ类到劣Ⅴ类的各种类型水质。通过对阿什河沿线底栖动物群落构成进行调查,结合典范对应性分析(CCA)对底栖动物群落与环境因子进行相关性分析得出结论,溶解氧和高锰酸盐指数为研究区域内底栖动物群落构成的主要限制因子。为分析不同水质条件下底栖动物种群变化成因和从生物学角度提出阿什河治理方法提供技术依据。     

复杂气井套管力学分析与可靠度评价

为建立考虑地层和套管参数随机性的套管可靠度评价理论方法，以便得到复杂井况下套管传统设计安全系数与可靠指标之间的关系，提出了非均匀地应力和内压联合作用下，沿套管最大外挤力方向管壁任意位置发生屈服失效时外壁等效均匀外挤力的计算方法；建立了套管抗挤和抗内压三轴强度计算公式以及有效内压计算方法；根据套管载荷和强度影响因素统计参数以及评价过程中参数测试标准值，利用蒙特卡洛法（MC）建立了完整的套管可靠度计算和评价方法；通过实例对传统安全系数与可靠指标的对应关系进行了研究。研究结果表明:指定条件下，套管安全系数与可靠指标之间存在对应关系；利用建立的方法编制计算程序可以为传统设计法中安全系数代表的安全程度进行量化；可靠度评价方法能够为安全系数的选取提供指导。     

Efficiency enhancement in solar air heaters by modification of absorber plate-a review

This paper outlines a complete review on modifications made on the absorber plate of solar air heaters in order to improve the turbulence and heat transfer rate, thereby efficiency. Corrugated sheets, fins, extended surfaces, wire mesh, porous medium, etc., are a few of the modifications used. Most of such alterations in the absorber plate resulted with an increase in efficiency but associated with drawback of increased pumping power due to raising friction factor. Pumping power is considered here as a predominant comparison parameters of various solar air heaters with different absorber plate in terms of effective efficiency.     

中国经济发展方式的转变动力及其作用途径

以全要素生产率增长动力作为经济发展方式的转变动力,本文采用1989-2013年4组省际面板数据经由可行广义最小二乘法实证估计了10个动力因素对全要素生产率增长率的贡献水平与作用途径。研究发现:技术创新水平、市场化水平、人力资本存量水平、异质性企业集聚水平和对外开放度的综合指数对中国全要素生产率增长率的回归估计系数分别为0.575 7,0.212 5,0.136 8,0.064 4和0.018,表明技术创新、市场化改革、人力资本积累、异质性企业集聚和对外开放是促进中国经济发展方式转变的直接动力因素。进一步的研究结果显示:技术创新和异质性企业集聚通过提高前沿技术进步率和生产效率变化率以及规模报酬收益率途径,市场化改革通过提高前沿技术进步率途径,人力资本积累与对外开放通过提高前沿技术进步率和规模报酬收益率途径,促进了中国全要素生产率增长。虽然产业结构变迁、城市化、基础设施建设、区域经济政策实施和金融发展对中国全要素生产率的增长表现为负向或拖累作用,但是,产业结构变迁与城市化能够提高前沿技术进步率,基础设施建设和区域经济政策能够提高规模报酬收益率,金融发展能够提高生产效率增长率和规模报酬收益率,这5项动力因素对促进中国全要素生产率增长的正向贡献有待提高。依据上述研究结论,本文提出尽快攻克制约生产率增长的核心技术,统筹考虑产业结构升级、城市化、基础设施建设和区域经济政策实施以及加快金融领域改革等政策建议,以期加快我国经济发展方式转变进程。     

贵州省三岔河流域水化学特征及其控制因素

对乌江源区三岔河流域枯水期和丰水期河水样品离子浓度及组成特征分析表明,河水主要的阴阳离子分别是HCO_3~–和Ca~(2+),分别占到总阴离子量的55%和总阳离子量的70%,与喀斯特地区流域相似。主要离子的时空分布的对比分析表明,Ca~(2+)、Mg~(2+)、Na~+、HCO_3~–、Cl~–枯水期浓度略高于丰水期,而K+、SO_4~(2–)、NO_3~–两期浓度变化相对较小;空间分布的多样化,反映了不同小流域在地质背景、生态环境、人为活动等方面的差异对河水离子的影响。通过Gibbs图分析表明,研究区河水水化学主要受到岩石风化的影响,通过阴阳离子三角图分析表明,研究区河水水化学主要受到碳酸岩盐的影响,并且硫酸广泛参与到岩石风化中,人为活动对流域水化学组成也有一定影响。     

Ecological risk and accessibility analysis to assess the impact of roads under Habitats Directive

We propose a method for the appropriate assessment of adverse effects of roads in compliance with the European Union Habitats Directive. The method incorporates an analysis of ecological risk of edge effects by the proposed roads with the related increase in accessibility. The method was tested on 30 km of planned forest roads inside an 8,000-ha reserve included in two Natura 2000 sites. As a result, the cumulative effect of 19 road segments was judged as not significantly affecting the integrity of the sites, although they made accessible an extra 314 ha. On the basis of the accessibility calculation, 20 ha of land were set aside from forest exploitation as a mandatory mitigation measure. The method objectively determined the cumulative adverse effects, enabled comparison of plan revisions and alternatives and proved to measure direct and indirect significant effects with a realistic effort in terms of field survey and geographic information system processing.     

Variability of pesticide residues in cauliflower units collected from a field trial and market places in Greece

To estimate the variability of pesticide residue levels present in cauliflower units, a total of 142 samples were collected from a field trial of a cooperative farmer, and 120 samples were collected from different market places in Thessaloniki, Greece. The collected samples were extracted using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction technique, and the residues were determined by liquid chromatography–tandem mass spectrometry. The developed method was validated by evaluating the accuracy, precision, linearity, limit of detection (LOD), and limit of quantification (LOQ). The average recoveries for all the analytes, derived from the data of control samples fortified at 0.01, 0.05, 0.1, and 0.2 mg/kg, ranged from 74 to 110% with a relative standard deviation of ≤8%. The correlation coefficient (R²) was ≥0.997 for all the analytes using matrix-matched calibration standards. The LOD values ranged from 0.001 to 0.003 mg/kg, and the LOQ was determined at 0.01 mg/kg for all the sought analytes. The matrix effect was found to be at a considerable level, especially for cypermethrin and deltamethrin, amounting to +90% and +145%, respectively. For the field samples, the unit-to-unit variability factors (VFs) calculated for cypermethrin and deltamethrin were 2.38 and 2.32, respectively, while the average VF for the market basket samples was 5.11. In the market basket samples, residues of cypermethrin, deltamethrin, chlorpyrifos, and indoxacarb were found at levels ≥LOQ and their respective VFs were 7.12, 5.67, 5.28, and 2.40.     

成都地区污染天气分型及其污染气象特征研究

污染天气分型研究对空气质量预报、污染源总量控制等具有重要的意义。基于2013年1月~2014年12月高空及地面天气形势划分了成都市的天气类型并探讨各天气类型下的空气质量状况及其污染天气特征,以期为空气质量预报和预警提供依据。结果表明,空气污染过程中,500 hpa环流形势主要有两槽一脊型、一槽一脊型、纬向型、槽脊同位相型等,其中两槽一脊型和槽脊同位相型控制下的空气质量最差。发生空气污染时,地面环流形势可分为高压型、高压后部型、高压底部型、低压型、低压顶部型、低压前部型、低压底部型、鞍型场型、冷锋前部型和均压场型,其中高压型、高压底部型、高压后部型控制下的空气质量最差。     

基于安徽省土地利用变化的地形梯度效应分析

为揭示地形因素与土地利用空间格局演变的关系,以安徽省2000年、2005年以及2010年Landsat TM影像和DEM数据为数据源,利用坡向、地形起伏度、坡度变率和地形位指数多种地形因子,并结合地学信息图谱分析理论从综合角度系统研究土地利用结构时空分异格局在地形梯度上的变化特点及其规律。结果表明:1)研究区主要的土地利用类型是耕地和林地,其次是建设用地和未利用土地,且建设用地面积逐期增加趋势显著。2)2000~2010年研究区不同土地利用类型在不同地形梯度区间的分异规律存在明显差异。低地形梯度范围是耕地、水域和建设用地的优势分布区;中地形梯度范围是草地的集中分布区;林地的优势分布区集中在高地形梯度范围。3)2000~2010年研究区土地利用图谱以稳定型和后期变化型为主,低地形梯度和高地形梯度是稳定型图谱的集中分布区,中低、中高和高地形梯度范围是后期变化型图谱的优势分布区。2000~2005年林地的优势分布区有向较低地形位梯度扩张的趋势,其中,耕地是主要的转入来源。2005~2010年耕地的优势分布区有向较高地形位梯度扩张的趋势,变化模式主要为:"林地–耕地"、"未利用地–耕地"和"草地–耕地"。