68 research outputs found
Avalanche Dynamics in Wet Granular Materials
We have studied the dynamics of avalanching wet granular media in a rotating
drum apparatus. Quantitative measurements of the flow velocity and the granular
flux during avalanches allow us to characterize novel avalanche types unique to
wet media. We also explore the details of viscoplastic flow (observed at the
highest liquid contents) in which there are lasting contacts during flow,
leading to coherence across the entire sample. This coherence leads to a
velocity independent flow depth at high rotation rates and novel robust pattern
formation in the granular surface.Comment: 5 pages, 3 figures in color, REVTeX4, for smaller pdfs see
http://angel.elte.hu/~tegzes/condmat.htm
First GIS analysis of modern stone tools used by wild chimpanzees (Pan troglodytes verus) in Bossou, Guinea, West Africa
Stone tool use by wild chimpanzees of West Africa offers a unique opportunity to explore the evolutionary roots of technology during human evolution. However, detailed analyses of chimpanzee stone artifacts are still lacking, thus precluding a comparison with the earliest archaeological record. This paper presents the first systematic study of stone tools used by wild chimpanzees to crack open nuts in Bossou (Guinea-Conakry), and applies pioneering analytical techniques to such artifacts. Automatic morphometric GIS classification enabled to create maps of use wear over the stone tools (anvils, hammers, and hammers/anvils), which were blind tested with GIS spatial analysis of damage patterns identified visually. Our analysis shows that chimpanzee stone tool use wear can be systematized and specific damage patterns discerned, allowing to discriminate between active and passive pounders in lithic assemblages. In summary, our results demonstrate the heuristic potential of combined suites of GIS techniques for the analysis of battered artifacts, and have enabled creating a referential framework of analysis in which wild chimpanzee battered tools can for the first time be directly compared to the early archaeological record.Leverhulme Trust [IN-052]; MEXT [20002001, 24000001]; JSPS-U04-PWS; FCT-Portugal [SFRH/BD/36169/2007]; Wenner-Gren Foundation for Anthropological Researc
Wet Granular Materials
Most studies on granular physics have focused on dry granular media, with no
liquids between the grains. However, in geology and many real world
applications (e.g., food processing, pharmaceuticals, ceramics, civil
engineering, constructions, and many industrial applications), liquid is
present between the grains. This produces inter-grain cohesion and drastically
modifies the mechanical properties of the granular media (e.g., the surface
angle can be larger than 90 degrees). Here we present a review of the
mechanical properties of wet granular media, with particular emphasis on the
effect of cohesion. We also list several open problems that might motivate
future studies in this exciting but mostly unexplored field.Comment: review article, accepted for publication in Advances in Physics;
tex-style change
Central Banking, Climate Change and Green Finance
Responsibility for financial and macroeconomic stability implicitly or explicitly lies with the central bank, which therefore ought to address climate-related and other environmental risks on a systemic level. Furthermore, central banks, through their regulatory oversight over money, credit, and the financial system, are in a powerful position to support the development of green finance models and enforce an adequate pricing of environmental and carbon risk by financial institutions. The central topic of this paperare the public financial governance policies through which central banks, as well as other relevant financial regulatory agencies, can address environmental risk and promote sustainable finance. The paperfirst discusses the reasons why central banks should be concerned with aligning finance with sustainable development. Second, the paperreviews the tools and instruments that can be utilized by central banks and financial regulatory agencies to address environmental risk and promote green finance and sustainable development. Third, the paperprovides a brief review of green public financial governance initiatives
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