絮凝浓缩武汉市巡司河底淤泥的研究

目的研究武汉市巡司河底淤泥在不同无机絮凝剂及PAM的助凝作用下淤泥清浑分界面的沉降速率、淤泥浓缩比以及淤泥沉降指数的变化情况。方法采用实验研究的方法,对巡司河底淤泥进行沉降实验,并通过沉降分析找到最佳脱水效果的脱水剂。结果当淤泥质量分数为10%时,Ca(OH)2取得的絮凝脱水效果最好,Ca(OH)2投加比为5 g/L,PAM投加比为0.04 g/L时,淤泥清浑分界面的沉降速率最大可达到3.7 cm/min,淤泥浓缩比为3.94,淤泥沉降指数为24.9%。结论 Ca(OH)2和PAM对巡司河底淤泥的脱水有促进效果,淤泥在Ca(OH)2和PAM共同作用下先后经历了自由沉降、絮凝沉降、区域沉淀和压缩沉降。     

Assessment practices in the policy and politics cycles: a contribution to reflexive governance for sustainable development?

ABSTRACT

This article examines systematic assessment practices linked to sustainable development policies. We consider five types of assessment—monitoring, policy evaluation, formal audit, peer review, and specialist reporting—and explore their fate in the policy and electoral politics cycles. In contrast to traditional views of the policy cycle, we note that systematic assessments provide complementary feedback around the entire policy cycle. However, despite this omnipresence, their policy relevance is usually severely limited, inter alia because the policy cycle captures only parts of the political reality. A major concern for politicians (but not necessarily for policy or governance scholars) that goes far beyond the formulation and implementation of policies is the broader cycle of electoral politics that determines the state's political personnel as well as government priorities. Here, we highlight that the findings of systematic assessments are often lost in a cacophony of voices to which politicians are more carefully attuned, such as media responses and opinion polls, implying that scientific evidence is simply ‘overwritten’ with other kinds of evidence representing alternative rationalities and priorities. Despite numerous shortcomings, the true value of systematic assessment practices lies in their potential to furnish ammunition to state and non-state actors interested in securing change.     

Conservation Focus on Europe: Major Conservation Policy Issues That Need to Be Informed by Conservation Science

Abstract:  Europe is one of the world's most densely populated continents and has a long history of human-dominated land- and seascapes. Europe is also at the forefront of developing and implementing multinational conservation efforts. In this contribution, we describe some top policy issues in Europe that need to be informed by high-quality conservation science. These include evaluation of the effectiveness of the Natura 2000 network of protected sites, implications of rapid economic and subsequent land-use change in Central and Eastern Europe, conservation of marine biodiversity and sustainability of fisheries, the effect of climate change on movement of species in highly fragmented landscapes, and attempts to assess the economic value of ecosystem services and biodiversity. Broad policy issues such as those identified are not easily amenable to scientific experiment. A key challenge at the science–policy interface is to identify the research questions underlying these problem areas so that conservation science can provide evidence to underpin future policy development .     

黄河水中沉积物与锌、镉液-固界面的作用

研究了黄河水中沉积物与重金属污染物Zn^2 、Cd^ 的离子交换吸附作用。结果表明,Zn^2 、Cd^2 在黄河水中主要以M（OH）^ 的形式与沉积物进行－价阳离子交换反应;在天然黄河水pH范围内,Zn^2 、Cd^2 的离子交换率都大于70％;随温度升高,Zn^2 、Cd^2 与沉积物的交换率增加,E-pH曲线向pH值减小的方向位移。     

Test procedure for evaluating the human–machine interface of vehicles with automated driving systems

Abstract

Objective: The human–machine interface (HMI) is a crucial part of every automated driving system (ADS). In the near future, it is likely that—depending on the operational design domain (ODD)—different levels of automation will be available within the same vehicle. The capabilities of a given automation level as well as the operator’s responsibilities must be communicated in an appropriate way. To date, however, there are no agreed-upon evaluation methods that can be used by human factors practitioners as well as researchers to test this.

Methods: We developed an iterative test procedure that can be applied during the product development cycle of ADS. The test procedure is specifically designed to evaluate whether minimum requirements as proposed in NHTSA’s automated vehicle policy are met.

Results: The proposed evaluation protocol includes (a) a method to identify relevant use cases for testing on the basis of all theoretically possible steady states and mode transitions of a given ADS; (b) an expert-based heuristic assessment to evaluate whether the HMI complies with applicable norms, standards, and best practices; and (c) an empirical evaluation of ADS HMIs using a standardized design for user studies and performance metrics.

Conclusions: Each can be used as a stand-alone method or in combination to generate objective, reliable, and valid evaluations of HMIs, focusing on whether they meet minimum requirements. However, we also emphasize that other evaluation aspects such as controllability, misuse, and acceptance are not within the scope of the evaluation protocol.     

A Systematic Procedure for Modeling Usability Based on Product Design Variables: A Case Study in Audiovisual Consumer Electronic Products

A systematic modeling approach to describing, prescribing, and predicting usability of a product has been presented. Given the evaluation results of the usability dimension (UD) and the measurement of the product’s design variables, referred to as the human interface elements (HIEs), the approach enables one to systematically assess the relationship between the UD and HIEs. The assessed relationship is called a usability model. Once built, such a usability model can relate, in a quantitative manner, the HIEs directly to the UDs, and thus can serve as an effective aid to designers by evaluating and predicting the usability of an existing or hypothetical product. A usability model for elegance of audiovisual consumer electronic products has been demonstrated.     

人工冻结法调控多年冻土区桩基础地温场的效果分析*

为了解决青藏铁路运营过程中,由于多年冻土地基的升温退化,部分多年冻土区桥梁桩基础承载性能下降,产生有害沉降变形,进而造成桥梁上部结构移位破坏,甚至部分桥梁桩基础在短时间内产生较大的沉降变形这一严重问题。基于当前多年冻土区桥梁桩基础沉降病害快速抢修技术空缺,提出人工冻结技术处置多年冻土区桥梁桩基础沉降病害的新设想,利用数值软件建立冻结管-桩基础三维模型分析该技术的可行性与调控效果,分析冻结参数、场地冻土条件等对冻结效果的影响。研究结果表明:人工冻结法可以快速降低桩周多年冻土温度;同时,冻结96 h可以对桩基地温场起到较好的冷却效果;冻结管至桩的距离对冻结效果的影响最为显著,冻土的含冰量越大,则降温速率越慢。     

一维脉冲波透过压电介质摩擦接触界面的传播

以压电材料为核心的结构和元件在装置中,总是和其他材料组合在一起,常用来传导表面波或承受动荷载,界面是其中的重要组成部分。当扰动很强时,会引起接触界面的局部滑移和分离,对结构安全产生威胁。笔者对一维脉冲波透过横观各向同性压电介质摩擦接触界面的传播进行了研究。利用Fourier分析的方法,将混合边值问题化为非线性代数方程组,通过迭代修正,确定了界面上分离、滑移和粘着3种区域的分布范围,同时计算了界面剪力和相对滑移速度的分布。笔者进一步丰富了压电弹性波动理论,利用波所携带的力学或电学信息,可望无损探测界面的接触状态及接触力等参量,对结构的安全评估与寿命预测具有重要的理论价值与实际意义。     

What use is CRELE? A response to Dunn and Laing

This paper responds to an original research article by Gemma Dunn and Matthew Laing in volume 76 of this journal. Their article describes an empirical study on the demand-side of the science-policy interface, and proposes a new framework by which to evaluate and/or design effective knowledge systems for influencing policymaking. In doing so, they also critique the commonly used CRELE framework, and propose that their alternative ACTA framework better summarises the most important aspects of scientific research for influencing decision-making. In response, this paper highlights some ambiguities commonly arising from the use of CRELE, to which Dunn and Laing have also succumbed, alongside ambiguities within CRELE itself, which they have failed to address. These difficulties highlight how empirical evidence of the sort collected by Dunn and Laing should not alone determine the worth of any knowledge-systems framework. This paper then discusses the dangers arising from a framework such as ACTA, were it to be used instead, and concludes that although CRELE is flawed, it does at least point to appropriate priorities for the use of evidence in public decision-making.     

积分比值法计算室内火灾烟气层分界面高度值的研究

在室内火灾双区域模型中,对火灾烟气层分界面高度值的判定具有重要意义,对其计算方法进行了研究。鉴于烟熏痕迹法和N百分比法存在的主观性和经验性的局限,介绍了一种积分比值法,给出了计算公式并采用Fortran95实现了编程计算。通过FDS5.0模拟了一种火灾场景,根据模拟得到的不同高度处的温度均值,应用积分比值法计算出了烟气层高度值,并将其与模拟得到的烟气层高度值进行了比较,结果表明两者较为吻合,应用积分比值法计算烟气层高度是可行的、准确的。