Stress fluctuation, crack renucleation and toughening in layered materials

It has been established that contrast in the elastic properties can lead to enhancement of fracture toughness in heterogeneous materials. Focussing on layered materials as a model system, we show that this enhancement is a result of two distinct phenomena – first, fluctuations in stress leading to regions where the stress intensity at the crack is considerably smaller than that of the macroscopically applied value; and second, the lack of stress intensity when a crack is at a compliant to stiff interface thereby requiring renucleation. Using theoretical, computational and experimental methods, we study two geometries – a layered material and a layered material with a narrow channel – to separate the two phenomena. The stress fluctuation is present in both, but renucleation is present only in the layered medium. We provide quantitative estimates for the enhanced toughness

Exploring Regional Development of Digital Humanities Research: A Case Study for Taiwan

This study analyzed references and source papers of the Proceedings of 2009-2012 International Conference of Digital Archives and Digital Humanities (DADH), which was held annually in Taiwan. A total of 59 sources and 1,104 references were investigated, based on descriptive analysis and subject analysis of library practices on cataloguing. Preliminary results showed historical materials, events, bureaucracies, and people of Taiwan and China in the Qing Dynasty were the major subjects in the tempo-spatial dimensions. The subject-date figure depicted a long-low head and short-high tail curve, which demonstrated both characteristics of research of humanities and application of technology in digital humanities. The dates of publication of the references spanned over 360 years, which shows a long time span in research materials. A majority of the papers (61.41%) were single-authored, which is in line with the common research practice in the humanities. Books published by general publishers were the major type of references, and this was the same as that of established humanities research. The next step of this study will focus on the comparison of characteristics of both sources and references of international journals with those reported in this article.Comment: 25 pages, 10 tables, 5 figure