高速公路绿化带对交通噪声的衰减效果研究

公路绿化带可对交通噪声产生一定衰减作用,这对于减轻路域环境噪声污染具有重要意义。然而,针对高速公路绿化带种植树种、种植密度、林带宽度等多种因素对降噪效果影响的研究尚属空白。该研究采用选取试验点进行原位调查的方法,研究了山东省3条主要高速公路路侧绿化带对交通噪声的衰减效果,并探讨了林带宽度和郁闭度对噪声衰减的影响。研究结果表明,高速公路绿化带对交通噪声有一定的减轻作用,但在不同的绿化模式下,衰减效果存在较大差别。交通噪声的绿化衰减同林带宽度有很大关系,对于较宽林带,靠近声源前半部分的林带对噪声有较好的减轻作用,但后半部分的减噪效果较小。林带的对噪声的绿化衰减与林带宽度以及宽度和郁闭度的乘积均呈极显著的线性关系。     

Lifting technique and abdominal belt usage: a biomechanical, physiological and subjective investigation

Some 10 male subjects carried out a repetitive lifting task for 15 min under four conditions on separate days. Subjects used either a squat lifting or a stoop lifting technique with or without an abdominal belt on each day. Measurements of spinal shrinkage, heart rate, perceived exertion and regional body pain were made under each condition. Although there was a significant difference in spinal shrinkage under all lifting conditions compared with shrinkage during 15 min of quiet standing (4.36 ± 2.24 vs. 1.13 ± 1.18 mm), there were no significant differences in shrinkage between the conditions. The subjects' heart rates were higher during the squat lift than the stoop lift (123 vs. 97 beats/min; p < 0.001). While the squat lift was perceived to be the safest lift by 90% of the subjects, 60% regarded this lift as the least preferred method (with or without the belt). Although all 10 subjects perceived the safest lifting method to involve the use of the belt, 50% rated the belt as their least preferred lifting condition. The findings cast doubt on the efficacy and acceptability of both abdominal belts and the practice of training workers in ‘safe’ lifting techniques and indicate that individual characteristics and preferences need to be considered when attempting to improve the safety of manual handling operations in industry.     

某铁矿胶带运输机移动卸料车的除尘系统

针对该矿胶带运输机移动卸料车定点卸料的作业特点,采用随卸料车移动的抽风罩、水平式风管接口装置及湿式除尘机组,构成简捷的除尘系统,有效地解决了卸料车作业时产生的粉尘污染问题。     

安徽沿江地区的区域发展特点与开发对策

安徽沿江地区虽然交通网络初具规模,城市专业化分工明显经济发展水平较低,属长江干流地区的低谷地带。另外,整个沿江地区应发挥水运与矿产资源的双重优势,促使建材,钢铁,石经等临江工业进一步开并予以合理布局。     

皮带巷粉尘浓度分布规律及全自动气水调节雾化除尘系统

鉴于传统的输煤皮带巷雾化除尘系统不能根据煤流高度自动调节雾化程度,难以达到预期除尘效果,以同忻煤矿输煤皮带巷为研究对象,基于COMSOL Multiphysics建立了输煤皮带巷煤流扬尘模型,研究了输煤皮带巷煤流高度对粉尘运移、分布的影响,继而设计了基于超声波物位传感器等多种传感器和V形调节电动球阀联动的气水调节雾化除尘系统。结果表明:在巷道高度1.5 m以上,煤流厚度越大,同一位置处的粉尘质量浓度越大,且以呼吸性粉尘为主,同时,在巷道走向沿程上,从风流入口处至下风向30~40 m范围内,粉尘质量浓度快速增长,污染严重;全自动气水调节雾化除尘系统可使呼尘质量浓度最高下降93.57%,具有良好的可行性和应用推广性。     

环太平洋地震带地震活动对中国大陆地震活动的影响分析

本文对1900年以来全球逐年发生的7.0级以上地震的活动图像进行详细分析,找出历史上地震活动与本年度地震活动分布相类似的年份,对这些年份之后的1～2年内发生在中国大陆、大华北、华东及安徽地区的中强震进行对比分析,力求得到较为合理的结论,为下年度的中国大陆、大华北、华东及安徽地区的地震趋势预测提供较为可靠的依据.分析得知:震后次年对中国大陆(主要是西部地区)影响最为明显;其次是对大华北地区的影响;然后是对华东地区(主要是海域)的影响;对安徽地区的影响较小.     

绿化林带对交通噪声的衰减效果

为了研究公路绿化林带的降噪效果,对路侧林带降低实时交通噪声的效果进行定位测量,并将交通噪声人工编辑为不同频率的噪声,在远离交通噪音的林带中进行模拟试验,测定林带对不同频率噪声的衰减效果.结果表明：林带对交通噪声衰减有一定作用,其作用随能见度增大而降低;林带降噪效果随林带宽度增大而增大,可决系数为0.990,但在30m宽度内随林带宽度的增加,噪声的降低速率有所下降;不同林带类型的降噪效果有所不同,所选30m宽林带类型中,国槐纯林的降噪效果最佳可达15.38dB,而杨树、柳树纯林降噪效果较弱,分别为7.25、11.02dB;林带对中低频率噪声的平均衰减作用高于高频率噪声.     

离心机考核测试和带式机脱水性能试验研究

为配合吉林化学工业股份有限公司 30万t乙烯工程A/O工艺废水处理工程化学污泥脱水的需要 ,进行了生产运行离心机性能考核测试和小型带式压滤机应用于化学污泥脱水的中试性能试验研究。本研究确定了小型带式压滤机最佳投泥量、投药量和产泥量等指标。达到了验收的各项技术经济指标 ,具有显著的经济和环境效益。     

Restraint use and seating position among children less than 13 years of age: Is it still a problem?

Introduction

The purpose of this study was to calculate national estimates and examine the extent to which children prematurely use adult seat belts and ride in the front seat of a vehicle during a 30 day period.

Methods

Data were obtained from a nationally representative cross-sectional random-digit-dial telephone survey that included child-specific questions on motor vehicle restraint use and seating position.

Results

Among children less than 13 years, parents reported an estimated 618,337 who rode unrestrained and more than one million who rode in the front seat of a vehicle at least some of the time in the past 30 days. During the same time period, close to 11 million children 8 years and younger reportedly used only adult seat belts.

Discussion

Our results highlight the need for continued outreach to parents regarding optimal restraint use and rear seating position for children every trip, every time.     

平原丘陵过渡带土壤有机碳空间分布及环境影响

为定量分析景观过渡带中土壤有机碳空间分布及环境影响,将环境因子纳入空间自回归模型与地理加权回归模型分析比较,并以普通最小二乘回归模型作对照.结果表明:土壤性质指标中,容重及有效铁与土壤有机碳存在极显著相关关系;地形及区位因子中,纬度、高程、坡度、粗糙度等稳定性因素与土壤有机碳存在极显著相关关系;土壤有机碳的局部集聚性多发生在核心景观过渡带;空间回归模型的拟合优度均优于普通最小二乘回归模型,估计值的空间自相关变化趋势与实测值一致,残差的空间模式显著减弱;能够灵活调整权函数与带宽的地理加权回归模型能够更好地分析土壤有机碳的空间变异.模型评价方面,GWR-1和GWR-2的残差平方和较OLS分别降低了20.717%和8.799%; SLM、SEM、GWR-1、GWR-2的AIC值较OLS分别减小了5.108、5.391、19.887和11.751.除本身存在的空间自相关外,模型中土壤性质指标及环境因子能大幅解释土壤有机碳的异质性.本研究引入辅助变量,运用空间回归模型分析了平原丘陵过渡带土壤有机碳的空间变异,可为生态恢复、环境变化指示及研究区典型柑橘区的区划提供依据.