垃圾填埋场生化降解指标测试及液气产量评估

以上海某综合垃圾填埋场作为研究对象,钻取不同龄期的生活垃圾测试固液气生化降解指标,并对全场的渗滤液产量以及填埋气产量进行评估.经过测试和计算,该处区域已开始稳定产甲烷,进入慢速降解阶段.其中,固相垃圾样的C/L（纤维素与木质素的比值）大部分集中在0.72~1.53之间;渗滤液pH值介于7.91~8.92,BOD介于1050~5780mg/L,COD介于2640~15200mg/L,NH₃-N介于2110~4360mg/L.引入固相、液相以及气相归一化指标β₁、β₂、β₃,用于评估填埋场降解阶段.其中,β₁介于0.56~0.83,β₂介于0.65~0.76,β₃介于0.97~1.02.β₁与β₂能够作为判定垃圾场降解阶段的指标,但β₃只能作为判定垃圾场是否处于稳定产甲烷阶段的指标.另外,建立考虑垃圾压缩-渗流耦合作用的渗滤液产量计算方法,垃圾自身渗滤液产率在70%~80%左右;采用垃圾两阶段降解模型计算填埋气产量,随着垃圾停止入场填埋,填埋气可收集量快速降低,至2025a降至峰值的3.88%,至2040a降至峰值的0.08%.     

压裂返排液的处理及回用

制备了沸石负载纳米TiO_2催化剂和蒙脱土负载纳米零价铁吸附剂,结合传统处理技术,构建了"絮凝—预氧化(Fenton氧化)—沸石负载纳米TiO_2催化臭氧氧化—蒙脱土载负纳米零价铁吸附"组合工艺,处理压裂返排液,考察了影响COD去除效果的因素。实验结果表明:在催化剂投加量1.0 g/L、臭氧通入时间5 min、吸附剂投加量5.0 g/L、吸附时间4 h的最佳条件下,COD从原水的4 032.60 mg/L降至37.03 mg/L,处理后出水各项指标均达到GB 8978—1996《污水综合排放标准》中的一级标准;80℃下,出水回用配制的压裂液黏度为4.4 mPa·s,高于自来水配制和压裂返排液配制的压裂液,耐温性有一定提升。     

Little by little,inch by inch: Project expansion assessments in the Papua New Guinea mining industry

Social impact assessment (SIA) has traditionally been practiced as an ex-ante predictive tool in the context of regulatory approval by government agencies. This model of SIA developed by Burdge and others is based on ‘greenfields’ development, of a new project going in to areas where there are no, or relatively few, similar types of development. The International Principles of SIA signalled a conceptual shift in the practice of SIA where greater emphasis is placed on the assessment and management of social issues across the life-cycle of developments. In addition forms of cumulative impact assessment have been developed for contexts where more than one project is likely to impact on populations or communities. With these changes to the traditional models of impact assessment there is a need to clarify how and when dedicated phases of ‘assessment’ might be undertaken over the life-cycle of a development. In the context of the mining industry, SIAs are increasingly required by governments for incremental increases in the size or impact of these operations. This paper reviews the development and application of Project Expansion Assessments (PEAs) for two large-scale mining operations in Papua New Guinea. It argues that a different set of assumptions need to underlie the model of IA for such assessments, with more emphasis on trajectories rather than baselines, a critical evaluation and attribution of effects, and the incorporation of adaptive management tools into the process.     

Alignment of the Lumbar Vertebrae in a Driving Posture

The purpose of this study was to define the anatomical arrangement of the lumbar spine in the mid-body sagittal plane of a human volunteer while in three postures: a driving posture; full flexion; and full extension. Radiographic images of the lumbar spine were made of a 33-year old 50th percentile male subject seated in a comfortable driving posture. Additional radiographs were made of the lumbar spine while the subject was postured in full voluntary flexion, and full voluntary extension. Anterior and posterior mid-sagittal vertebral endplate positions were plotted on an x-y coordinate system for each posture. Anterior and posterior disk thicknesses, and the positions of the centers of each vertebra were numerically determined using information from the plots. Disk thicknesses were then graphed and comparisons made for each posture. The arrangements of the centers of vertebrae were graphed and compared for the three different postures. The arrangement of the lumbar vertebrae tended toward that of full voluntary flexion while the subject was in a normal driving posture. Anterior disk thickness was a sensitive indicator of posture, while posterior disk thickness was not. While in a driving posture, the lower back approximated a straight-line that was nearly parallel to the seat back axis. The observations support those of an earlier study. Since soft tissue spinal elements can only be damaged by applying tensile forces in excess of their tolerance, the anterior elements of the lumbar spine would not be directly threatened in low velocity frontal collisions, since anterior elements would be in relative compression. Tension injury to the anterior structures as a result of a rear-end collision would first require reversing the preimpact conditions imposed by the normal driving posture. Tension injury to the posterior spinal elements resulting from low velocity rear-end collisions would be unlikely since axial compression loading would also diminish tension stress in posterior soft tissue structures. Any compression injury to posterior elements resulting from rear-end collisions would first require reversing the pre-impact conditions imposed by the normal driving posture.     

The ‘new’ economics of iron and steel

The author commences his analysis of the iron and steel industry by examining the historical background of the industry, and discusses its importance for the world economy. He examines the implications for the world industry of the successful development of the steel industry in Japan, and traces the evolution of a commodity cartel in the iron ore market, analysing the price levels of the commodity in the ‘free’ and ‘controlled’ markets. Following a discussion of the role of energy and coking coal supplies in the industry, the author examines the evolution of this industry in the less developed countries, with particular reference to the role of technology in the industry's development. He concludes that there have been important structural changes in the world industry, embraced by the concept of ‘partial demise’.     

土地流转与农户收入增长——基于收入结构的视角

农户参与土地流转能否产生正的收入效应是一个广为社会各界关注的问题,然而已有的经验研究结论却大相径庭,文章以为对土地流转异质性影响的忽视是导致诸多土地流转收入效应研究结论不一致的关键。基于此,文章应用2010—2018五轮中国家庭追踪调查数据(CFPS),分析土地流转对不同农户类型、不同收入来源的影响差异。基本实证结果表明:第一,土地流转确实会增加农户收入,但是主要表现为对转出农户有正的收入效应,对转入农户的家庭纯收入影响并不明显。第二,土地流转对转入农户与转出农户的不同类型收入的影响并不一致。转出户工资性收入增长幅度远高于经营性收入下降幅度,工资性收入对转出户家庭纯收入的增长贡献接近80%;转入户的经营性收入增长无法弥补工资性收入下降,导致家庭总收入水平没有显著变化。以上实证结果经双重差分模型、处理效应模型等一系列模型敏感性分析后并未改变,表明文章的基本结论是稳健的。进一步地,文章对收入异质性的原因进行分析,发现土地流转对不同农户的劳动力资源配置决策影响存在差异,转出户外出务工与创业的概率增加,非农生产的劳动力投入增加;而转入户则在农业生产中投入更多资源,包括家庭农业劳动参与增加以及农业投入增加。文章进一步的政策讨论也发现,由于转出农户对技术改进的依赖性较弱,转出农户只需要保证能够找到一份替代工作就可以获得更高的收入;但对转入农户而言,由于缺乏足够的技术帮扶,所以他们的土地生产改进有限,反而难以产生土地流转理论提到的资源配置优化,这可能会限制土地流转市场的进一步扩大。综上,文章研究为优化土地流转政策、提高土地流转参与率,并最终实现农户的社会福利改善提供了一定的理论与经验证据支持。     

大气腐蚀与装备环境工程

列举了大气腐蚀对武器装备所造成的危害的事例,阐述了武器装备大气腐蚀的环境因素和腐蚀行为预测,论述了大气腐蚀与装备环境工程的关系及大气腐蚀与防护研究在装备环境工程中的重要作用,强调了大气腐蚀与防护研究是装备环境系统工程中一项基础性工作。     

天南星（Arisaema erubescens Schott）对钉螺（Oncomlania hupensis）的毒杀作用

近年来,血吸虫病在我国又有回升的势头,采用植物灭螺进而消灭血吸虫病是控制血吸虫病蔓延的有效方法.实验研究了一种新型灭螺植物——天南星(ArisaemaerubescertsSchott)的灭螺效果和机理.采用天南星植物水浸液用于灭螺(Oncomlaniahupensis)实验,并检测天南星处理后钉螺肝脏生理生化指标的变化.结果显示,天南星全株均具有较强的灭螺效果,其中块茎灭螺效果最好:0.1%块茎水浸液处理3天后钉螺死亡率达88.4%,5天后达100%;天南星不同部位的灭螺效果为:块茎>叶>茎.天南星块茎水浸液处理钉螺后,随处理浓度的增加和处理时间的延长,钉螺肝脏丙二醛(MDA)含量显著升高,而过氧化物酶(POD)和超氧化物歧化酶(SOD)活性显著降低.天南星水浸液可引起钉螺肝细胞的过氧化损伤,导致其抗氧化能力下降,从而降低了其代谢和解毒功能.研究结果表明,天南星是一种具有良好灭螺效果的植物,可成为构建植物群落生态工程灭螺林新的物种资源.     

Developing a Monitoring Program for Invertebrates: Guidelines and a Case Study

Abstract:  Invertebrates provide the majority of ecosystem services; thus, it is important that they be inventoried, monitored, and protected. Nevertheless, inventories, monitoring, and management generally focus on vertebrates and flowering plants. Consequently, there are few guidelines or case studies for invertebrates. We present a procedure for developing a monitoring program for species-rich invertebrates that entails (1) characterizing the community; (2) identifying surrogates for biodiversity; and (3) establishing efficient methods to monitor surrogates and any ecologically important or sensitive taxa. We used these procedures, biodiversity-based statistical advances, and a survey of arthropods to develop a monitoring plan for the forests of Shenandoah National Park, Virginia (U.S.A.). Our case study revealed that mixed hardwood and hemlock forests had significantly different compositions of arthropods in their soil and understory strata. Of the 10 orders tested Coleoptera and Hymenoptera were the only two to pass most of the five surrogate tests, and their combination improved predictions of overall arthropod diversity. Because arthropods represent the majority of macroscopic species in most ecosystems, the ability of this assemblage to predict overall arthropod diversity makes it a powerful surrogate. Of the 11 collecting methods used, the beat-sheet method was the most efficient for monitoring this surrogate assemblage. To complement this coarse-filter approach to monitoring at-risk, invasive, or other important taxa (fine filter), we used ordination analyses to match 66 taxa with the methods that most effectively sampled them. Our methods serve as a model for developing an invertebrate monitoring plan and should facilitate linking such monitoring with ecosystem functions and management.