Numerical Simulation of the Flow Field and Concentration Distribution in the Bulk Growth of Silicon Carbide Crystals

The physical vapor transport (PVT) method is being widely used to grow large-size single SiC crystals. The growth process is associated with heat and mass transport in the growth chamber, chemical reactions among multiple species as well as phase change at the crystal/gas interface. The current paper aims at studying and verifying the transport mechanism and growth kinetics model by demonstrating the flow field and species concentration distribution in the growth system. We have developed a coupled model, which takes into account the mass transport and growth kinetics. Numerical simulation is carried out by employing an in-house developed software based on finite volume method. The results calculated are in good agreement with the experimental observation.

Authority files: Breaking out of the library silo to become signposts for research information

Authority files serve to uniquely identify real world ‘things’ or entities like documents, persons, organisations, and their properties, like relations and features. Already important in the classical library world, authority files are indispensable for adequate information retrieval and analysis in the computer age. This is because, even more than humans, computers are poor at handling ambiguity. Through authority files, people tell computers which terms, names or numbers refer to the same thing or have the same meaning by giving equivalent notions the same identifier. Thus, authority files signpost the internet where these identifiers are interlinked on the basis of relevance. When executing a query, computers are able to navigate from identifier to identifier by following these links and collect the queried information on these so-called ‘crosswalks’. In this context, identifiers also go under the name controlled access points. Identifiers become even more crucial now massive data collections like library catalogues or research datasets are releasing their till-now contained data directly to the internet. This development is coined Open Linked Data. The concatenating name for the internet is Web of Data instead of the classical Web of Documents.

The Kandhkelgaon Story: a bold bid by women in Kandhkelgaon Village, Saintala Block, Bolangir District, to break out of their poverty trap

One third of the people on earth who are described as living in absolute poverty are found today in India. “These people,” says Mr B K Satpathy, “are caught in a poverty trap’.” “Poverty trap?” we ask. “These are creative weavers; their cloth has a distinctive style, but those who supply their thread also take away and sell the cloth, paying just a small labor cost for each saree. If they are skilled and work hard this amounts to only 25-30 rupees (60-70 US cents) per day.” Under this arrangement, weaving does not provide enough to live on, and people are seeking ways to escape their entrapment in poverty. (Pdf contains 6 pages).