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101.
The way that the media reports and comments on key events in the fragmented global climate governance landscape is one important route to strengthening public accountability of such governance. Editorials and other opinion pieces provide key contributions to the public sphere, but have been almost entirely neglected in media research on climate change. Another understudied aspect in such research is the reporting on the fragmentation of global climate governance across numerous forums. This article provides an exploratory approach to address these two research gaps. It presents a quantitative analysis of how often leading newspapers in seven countries (Finland, India, Laos, Norway, South Africa, UK and USA) wrote about 18 meetings in six different global climate governance forums between 2004–2009 and whether they provided commentaries about them. The study shows that media coverage (articles and opinion pieces) is limited or absent for many meetings that are not attended by heads of state, are the launch of a new process or do not have the convening power of the United Nations Framework Convention on Climate Change. The pattern of coverage differs significantly among individual newspapers and there is no clear distinction between developed and developing country newspapers. The article concludes that overall news coverage, and editorial commentary in particular, of global climate meetings in the selected newspapers is too low and too patchy to significantly support domestic publics to hold their own (and indirectly other) governments accountable with regard to fragmented global climate governance.Policy relevanceThis study is instructive for the media and civil society, who should both act as accountholders of governments with regard to how they act in global climate governance and its implementation. Reporting and commentaries need to reflect the overarching process, not only sporadic coverage of high-level meetings, but also critical analysis of what is achieved. They should also take a broader scope in terms of the kinds of meetings and processes in global governance that they cover. Civil society should encourage the media to increase coverage along these lines, e.g. by adequate monitoring of government actions (or lack thereof) and share this with the media. 相似文献
102.
The aim of this study is to numerically model the fracture system at percussive drilling. Because of the complex behavior of rock materials, a continuum approach is employed relying upon a plasticity model with yield surface locus as a quadratic function of the mean pressure in the principal stress space coupled with an anisotropic damage model. In particular, Bohus granite rock is investigated, and the material parameters are defined based on previous experiments. This includes different tests such as direct tension and compression, three‐point bending, and quasi‐oedometric tests to investigate the material behavior at both tension and confined compression stress states. The equation of motion is discretized using a finite element approach, and the explicit time integration method is employed. Edge‐on impact tests are performed, and the results are used to validate the numerical model. The percussive drilling problem is then modeled in 3D, and the bit‐rock interaction is considered using contact mechanics. The fracture mechanism in the rock and the bit penetration‐ resisting force response are realistically captured by the numerical model. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
103.
A numerical study of the influence from pre‐existing cracks on granite rock fragmentation at percussive drilling 下载免费PDF全文
Mahdi Saadati Pascal Forquin Kenneth Weddfelt Per‐Lennart Larsson Francois Hild 《国际地质力学数值与分析法杂志》2015,39(5):558-570
The aim of this study is to investigate the effect of pre‐existing, or structural, cracks on dynamic fragmentation of granite. Because of the complex behavior of rock materials, a continuum approach is employed relying upon a plasticity model with yield surface locus as a quadratic function of the mean pressure in the principal stress space coupled with an anisotropic damage model. In particular, Bohus granite rock is investigated, and the material parameters are chosen based on previous experiments. The equation of motion is discretized using a finite element approach, and the explicit time integration method is employed. The pre‐existing cracks are introduced in the model by considering sets of elements with negligible tensile strength that leads to their immediate failure when loaded in tension even though they still carry compressive loads as crack closure occurs because of compressive stresses. Previously performed edge‐on impact tests are reconsidered here to validate the numerical model. Percussive drilling is simulated, and the influence of the presence of pre‐existing cracks is studied. The results from the analysis with different crack lengths and orientations are compared in terms of penetration stiffness and fracture pattern. It is shown that pre‐existing cracks in all investigated cases facilitate the drilling process. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
104.
制备净化水用直接破碎活性炭可选用直接活化和炭化-活化两种工艺路线。研究结果表明,利用直接活化法生产的活性炭性能较佳,其最佳工艺参数为:粒度0.45mm的煤料,在900℃T,升温速率控制为15℃/min.进水量控制为2.8ml/min,直接活化5h,既能够制备出各项指标均达国家标准的净化水用煤质直接破碎活性炭。 相似文献
105.
澜沧江中上游鱼类生物多样性现状初报 总被引:10,自引:0,他引:10
对澜沧江上游及支流的鱼类和环境调查显示流域片段化对鱼类生物多样性产生了较大的影响。从漾濞江和西洱河的比较可以看出,前者因为没有梯级电站,鱼类的种类和数量并无太大的变化,而西洱河由于过度的梯级开发和污染,鱼类濒于灭绝,洱海由于江湖的隔绝,外来种的引入使得土著鱼类种群数量急剧减少。干流上大坝(漫湾水电站)的修建使得流水变为静水环境而产生一系列的变化使鱼类的种类和种群数量产生变化。 相似文献
106.
The particle size distributions of fault gouge from the San Andreas, the San Gabriel, and the Lopez Canyon faults in Southern California were measured using sieving and Coulter-Counter techniques over a range of particle sizes from 2 m to 16 mm. The distributions were found to be power law (fractal) for the smaller fragments and log-normal by mass for sizes near and above the peak size. The apparent fractal dimensionD of the smaller particles in gouge samples from the San Andreas fault, the San Gabriel fault and the Lopez Canyon gouge were 2.4–3.6, 2.6–2.9 and 2.4–3.0, respectively. The averageD for the Lopez Canyon gouge was 2.7±0.2, which is in agreement with earlier studies of this gouge using planar 2-D sections. The fractal dimension of the finer fragments from all three faults is observed to be correlated with the peak fragment size, with finer gouges tending to have a largerD. A computer automaton is used to show that this observation may be explained as resulting from a fragmentation process which has a grinding limit at which particle reduction stops. 相似文献
107.
108.
Rock mass characterization using photoanalysis 总被引:3,自引:0,他引:3
John A. Franklin Norbert H. Maerz Caralyn P. Bennett 《Geotechnical and Geological Engineering》1988,6(2):97-112
Summary Rock formations are distinguished from each other by measuring first the properties of the intact rock, and second those of the jointing. Whereas simple methods are available for measuring intact rock properties, those available for measuring jointing remain slow, expensive, and sometimes dangerous. Digitized photographs (photoanalysis) may provide a solution. In this paper, the new techniques of photoanalysis are reviewed together with applications, promising areas for research, and also some obstacles that remain to be overcome. Aspects of the rock mass that lend themselves to photoanalytical measurement include those of individual joints, such as persistence, orientation and roughness, and those relating to the mass as a whole, such as block size and the spacing or intensity of jointing. Photoanalysis can also be applied to measurement of blasting. It allows characterization of the rock about to be blasted, helping the engineer to predict fragmentation and to design an appropriate blasting pattern. Afterwards, the same methods can be used to measure fragmentation, overbreak and backbreak, for quality control and for diagnosis of problems.Presented at the 28th US ROck Mechanics Symposium, Tucson, Arizon, 29 June–1 July 1987. 相似文献
109.
110.
分析了大口径嵌岩钻进面临的主要技术难点,并对目前国内常用的3种大口径嵌岩钻进方法-牙轮/滚刀钻进法、冲击钻进法(包括无循环和反循环)和气动/液动潜孔锤钻进法的技术现状作了介绍,提出了提高我国大口径嵌岩钻进技术水平的建议。 相似文献