Understanding large plastic deformation of SiC nanowires at room temperature

Tensile behaviors of SiC [111] nanowires with various possible microstructures have been investigated by molecular-dynamics simulations. The results show that the large plastic deformation in these nanowires is induced by the anti-parallel sliding of 3C grains along an ultra- thin intergranular amorphous film parallel to the (11¯1) plane and inclined at an angle of 19.47◦ with respect to the nanowire axis. The resulting large plastic deformation of SiC nanowires at room temperature is attributed to the stretching, breaking and re-forming of Si–C bonds in the intergranular amorphous film, which is also evident from the sawtooth jumps in the stress-strain response

Microstructural evolution and formation of nanocrystalline intermetallic compound during surface mechanical attrition treatment of cobalt

Nanocrystalline intermetallic Co3Fe7 was produced on the surface of cobalt via surface mechanical attrition (SMA). Deformationinduced diffusion entailed the formation of a series of solid solutions. Phase transitions occurred depending on the atomic fraction of Fe in the surface solid solutions: from hexagonal close-packed (11% Fe). Nanoscale compositional probing suggested significantly higher Fe contents at grain boundaries and triple junctions than grain interiors. Short-circuit diffusion along grain boundaries and triple junctions dominate in the nanocrystalline intermetallic compound. Stacking faults contribute significantly to diffusion. Diffusion enhancement due to high-rate deformation in SMA was analyzed by regarding dislocations as solute-pumping channels, and the creation of excess vacancies. Non-equilibrium, atomic level alloying can then be ascribed to deformation-induced intermixing of constituent species. The formation mechanism of nanocrystalline intermetallic grains on the SMA surface can be thought of as a consequence of numerous nucleation events and limited growth. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

No Excuses Charter Schools: A Meta-Analysis of the Experimental Evidence on Student Achievement

While charter schools differ widely in philosophy and pedagogical views, the United States’s most famous urban charter schools typically use the No Excuses approach. Enrolling mainly poor and minority students, these schools feature high academic standards, strict disciplinary codes, extended instructional time, and targeted supports for low-performing students. The strenuous and regimented style is controversial amongst some scholars, but others contend that the No Excuses approach is needed to rapidly close the achievement gap. We conduct the first meta-analysis of the achievement impacts of No Excuses charter schools. Focusing on experimental studies, we find that No Excuses charter schools significantly improve math scores and reading scores. We estimate gains of 0.25 and 0.16 standard deviations on math and literacy achievement, respectively, as the effect of attending a No Excuses charter school for one year. Though the effect is large and meaningful, we offer some caveats to this finding and discuss policy implications for the United States as well as other countries

Pan-cancer analysis of whole genomes

Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

Fault Diagnosis and Fault-Tolerant Control for Aircraft Subjected to Sensor and Actuator Faults

Control & Simulatio

Spatial planning and urban resilience in the context of flood risk: A comparative study of Kaohsiung, Tainan and Rotterdam

Spatial planning is increasingly being considered as an important mechanism in coping with flood risk due to climate change. One of the reasons for this is that engineering approaches are increasingly expensive and cannot provide complete certainty of protection against climate-related floods. The thesis examines whether and how spatial planning is used in urban areas to promote resilience to flood risk and climate change. In this study, planning is considered as the regulation of physical implementation as well as the process of policy-making that guides spatial development. This process mainly involves the interaction and collaboration between actors (both public and private). The notion of resilience is being used more and more in discussions of complex issues like the impact of climate-related flood risks on spatial development. The interpretations of resilience can vary significantly depending on the local context, the focus of spatial development and the interests of the actors involved in decision- making. The study proposes six characteristics of planning decision-making that can help to promote the resilience of cities. These comprise: (i) considering the current situation, (ii) examining trends and future threats, (iii) learning from previous experience, (iv) setting goals, (v) initiating actions, and (vi) involving the public. The importance of these characteristics over time for policy and practice is examined according to empirical evidence from detailed case study analysis. Six case studies are presented, four in Taiwan and two in the Netherlands. In all of the case studies, the issue of flood risk and spatial development is considered important by policy- makers, but the planning strategies used to tackle climate-related flood risks are often different, as are the experiences of flooding and governance arrangements. The information gathered is primarily based on interviews and the review of planning policies, government reports and research documents. Comparative analysis is a central focus of the study. The analysis has both a national and international perspective, comparing cases within Taiwan and between Taiwan and the Netherlands. The national comparison examines the way in which local planning governance is addressed in shaping decisions to deal with flood risks. This can vary among cases which share similar spatial development objectives and national institutional framework. The international comparison between Taiwan and the Netherlands examines the roles of planning to promote urban resilience in the context of flood risk and climate change. Three conclusions can be drawn. First, the interpretation of resilience is dependent on the views and interests of the actors involved. These change over time and can be seen in different episodes of policy-making. Second, the importance of the different assessment characteristics varies from one case to another. The interests of the leading actors, the interpretations of flood risks and the framework of local collaboration are all major factors that shape these differences. These factors are often associated with planning traditions and relatively stable in resistant to change. Third, when there is a collaborative framework for planning involving multiple actors, the result is a more comprehensive set of strategies in dealing with flood risk.UrbanismArchitecture and The Built Environmen

Climate awareness, preparation resilience and measuring adaptability of the governance system in Rotterdam for flood risks

UrbanismArchitectur

An integrated scenario-based measuring for transportation resilience: A case study of Pazhou, Guangzhou, Greater Bay Area

Landscape Architectur

Scenario-based coastal resilience assessment of Green-Blue-Gray infrastructure: A case study of Marine City, Shenzhen, Greater Bay Area

Landscape Architectur