Impact of climate change on food security of small islands: The case of Mauritius

This paper studies the implications of high food prices resulting from climate change on food security in small islands, using Mauritius as a case‐study. Climate change may adversely impact prices of agricultural commodities. The study derives and calculates the government costs and the welfare effects of an increase in the world price of rice on consumers in Mauritius. Using an equilibrium displacement model, this study finds that an increase in the price of rice by 35%, as predicted by the literature on climate change and rice prices, will result in an increase of 28.8% in government spending, representing the additional outlays to support the subsidy scheme for food security. Using 2012 as the baseline, the welfare analysis results suggest that consumer surplus for ration rice consumers increases by 626 million Mauritian Rupees (MUR) or US$18 million while consumer surplus decreases by MUR454 million (US$13 million) for basmati rice consumers.     

基于SVM的通风系统故障诊断惩罚系数与核函数系数优化研究

使用支持向量机（SVM）方法对矿井通风系统进行故障诊断,存在惩罚系数（c）和核函数系数（g）,通过人工方法选取效率低、难以达到较高准确率并且出现过拟合的问题。为了提高矿井通风故障诊断的效率、准确率,同时避免过拟合现象,提出了一种改进遗传算法（GA）,在故障诊断过程中对支持向量机的c,g参数进行优化。经过多组试验分析,研究结果表明:用遗传算法优化的SVM矿井通风故障诊断系统相比于未优化系统的故障诊断准确率有所提升,参数未优化前故障诊断的准确率为60%,优化后的准确率为97.894 7%,并且优化参数经过大数据样本验证,未出现过拟合现象,证明了本文提出方法的有效性。     

某大型机加车间数控机床减噪工程测试与分析研究

为研究大型机加车间噪声减噪工程现状效果和特点,选取某大型机加车间数控机床为研究对象,对其进行减噪工程治理,现场实测了治理前和治理后的噪声数据,并对噪声测量结果进行分析。研究结果表明:数控机床操作人员8 h连续等效A声级从治理前的89.2 dB(A),降到治理后的74.3 dB(A),降低了16.7%.;数控机床操作岗位位置测点,在加工1个机件的测量时间段里,噪声值从治理前的85.9 dB(A),降到治理后的55.1 dB(A),降低了33.85%;对机加车间现场布置了67个测点,在加工1个机件的测量时间段里进行测量,得到该车间噪声治理前和治理后噪声分布图;对数控机床减噪工程治理前和治理后的频谱进行了分析,得出治理前和治理后各自的最大声级所在频段不随距离的改变而改变,高频减噪效果显著。     

Investigating the effects of monthly weather variations on Connecticut freeway crashes from 2011 to 2015

IntroductionThe objective of this research is to investigate the effects of monthly weather conditions on traffic crash experience on freeways, considering the interactions between weather, traffic volumes, and roadway conditions. Methods: Data from the state of Connecticut from 2011to 2015 were used. Random parameters negative binomial models with first-order, autoregressive covariance were estimated for representative types of freeway crashes (front-to-rear, sideswipe-same-direction, and fixed-object), most severe crashes (i.e., fatal and injury crashes), and non-injury crashes (i.e., property-damage-only crashes). Results: Major findings are that variations in monthly traffic volumes, roadway geometry, and weather conditions explain much of the variations in monthly traffic crashes. Time effects exist in the panel monthly data for all types of crashes. Taking into account this effect improves model prediction results. When the raw weather measures are highly correlated, using dimension reduction techniques helps to extract more interpretable weather factors. By considering the interaction effects between roadway condition variables, additional findings were found. In general, lower temperature, more heavy fog days, decreased precipitation, lower wind speed, higher monthly traffic volumes, and narrower inside shoulder were found to be associated with higher monthly crashes. The effects of area type and outside shoulder width change dramatically as the number of through lanes changes. Practical applications: The findings of this research could help researchers and general readers gain a better understanding of the effects of monthly weather conditions and other roadway factors on freeway crashes and give engineers practical guidelines on improving freeway safety.     

炼油污泥的热化学清洗处理

以广西省某炼化企业污水处理系统的炼油污泥为研究对象,采用热化学法对其进行清洗处理。对比了含油率的测定方法,对8种药剂进行筛选和复配,同时通过正交实验确定清洗工艺参数,并对重金属污染物进行分析。实验结果表明:8种药剂中Na2Si O3的清洗效果最好,而复配药剂(Na OH与Na2Si O3的质量比为1∶5)的清洗效果优于单一Na2Si O3;在清洗温度70℃、搅拌转速350 r/min、搅拌时间30 min、复配药剂质量分数5.0%、液固比3∶1的最佳工艺参数下,单级洗油率为63.6%,三级洗油率为69.4%、残油率为15.6%;清洗前后炼油污泥中Zn,Mn,Cu,Cr等重金属含量均超过GB 15618—1995《土壤环境质量标准》三级标准限值。     

泽龙湖景观水污染治理及生态修复

为了去除泽龙湖微污染景观水中的氮、磷及有机物等污染成分,采用人工增氧和浮田型生态岛技术对泽龙湖景观水进行了生态修复。结果表明,人工增氧能很好地氧化水中有机物,生态岛水生植物可有效地吸收氮和磷,处理后湖水可达到《地面水环境质量标准》(GB 3838—2002)中的Ⅳ类标准。     

Research on a small-noise reduction method based on EMD and its application in pipeline leakage detection

The noise included in pipeline pressure signal is a small noise whose energy takes a small proportion of pressure signal and is concentrated on high frequency components. However, it will influence pipeline leakage identification and even cause false alarms. Thus, a small-noise reduction method based on EMD (SNR-EMD) is proposed to remove small noise from pressure signal. EMD is applied for extracting the mean envelope of the signal. Then, small fluctuations around the mean envelope are considered to be small noises. Meanwhile, end effect of SNR-EMD is restrained by extrema mirror extension (EME). The results of simulation studies with SNR-EMD show that the larger the noisy signal's signal-to-noise ratio (SNR) is, the better noise reduction effect becomes. And SNR-EMD considered as a low-pass filter removes or reduces the high frequency components. Furthermore, superiorities of SNR-EMD are verified by comparison studies with wavelet packet transform (WPT) and singular value decomposition (SVD). Finally, a case study of leakage identification shows that SNR-EMD can improve the performance of leakage identification and reduce the possibility of false alarms, which makes much easier and further effective to distinguish the leakage mode from other modes after removing noise from pressure signal.     

海洋工程用新型牺牲阳极设计与性能研究(Ⅰ)——小尺寸阳极静态海水试验研究

目的设计一种新型牺牲阳极,满足海洋工程钢结构阴极保护不同时期保护电流需求,节约牺牲阳极用量。方法通过改变常规阳极面积与质量比,分别设计面积相同和质量相同的新型阳极和常规阳极,并进行静态海水阴极保护对比试验。结果面积与常规阳极相同的新型阳极,在节约质量近50%的基础上,实现了与常规阳极相近的发生电流;质量与常规阳极相同的新型阳极,表面积增加近70%,实现了初期发生电流增加18%,试验阶段发生电流增加14%,被保护钢试样的快速极化。结论通过增加常规阳极面积与质量比,降低接水电阻,增加发生电流的设计思路是可行的。     

浅析山地型风力发电场生态环境影响

随着中国风电产业的迅速发展,风电场建设越来越多,风电场的建设对调节能源结构,减轻环境污染,减少温室气体排放,缓解电力紧张都有着重要的意义.风力发电对生态环境的不利影响主要表现在施工期和运行期,施工期生态影响为植物量损失,运行期生态影响为对鸟类和景观影响.以五凤山风电场为例,探讨了山地型风电场对生态环境的影响.主要为对植被、鸟类和景观的影响,并提出了有效的环境保护措施.     

Achieving SDG 6: water resources sustainability in Caribbean Small Island Developing States through improved water governance

Scientific findings confirm that Small Island Developing States (SIDS) in the Caribbean are experiencing droughts and sea level rises that are contributing to saline intrusion of underground aquifers and surface water sources. This paper, using Trinidad as a case study, analyses water governance challenges in meeting Sustainable Development Goal (SDG) 6, which addresses the sustainability of water resources. Interviews were conducted with professionals from multi‐disciplinary backgrounds. Also, data provided by the water agency were analysed to evaluate water governance practices. The main contribution of this paper is the generation of a blend of policies, good practices and tools to confront growing threats to water security and to attain sustainable development in Caribbean SIDS in an era of climate change and increasing non‐climatic stressors. The paper concludes that economic, environmental and human resources, reformed administrative and legislative systems, and technological tools are fundamental to achieving good water governance. Moreover, an array of complementary policies and technologies is needed to resolve water governance issues. However, political will to implement sustainable water resources management is the greatest challenge in attaining SDG 6.