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Freeze-cast alumina that has been partially sintered. The freezing direction in the image is up. Freeze-casting, also frequently referred to as ice-templating, freeze casting, or freeze alignment, is a technique that exploits the highly anisotropic solidification behavior of a solvent (generally water) in a well-dispersed solution or slurry to controllably template directionally porous ...
A furnace lining brick, or an investment casting mold, can be easily fabricated using this method. Recently there was a flurry of interest in freeze-casting at the University of Bath, UK, which led most significantly to two doctoral theses, by J. Laurie in 1995 and by M. Statham in 1998. Taken together in chronological order, these form a good ...
A bronze casting showing the sprue and risers. A riser, also known as a feeder, [1] is a reservoir built into a metal casting mold to prevent cavities due to shrinkage.Most metals are less dense as a liquid than as a solid so castings shrink upon cooling, which can leave a void at the last point to solidify.
Directional freezing can freeze water, from only one direction or side of a container, into clear ice. [1] [2] [3] Directional freezing in a domestic freezer can be done by putting water in a insulated container so that the water freezes from the top down, and removing before fully frozen, so that the minerals in the water are not frozen. [4]
Object lessons were important elements in teaching during the Victorian era of the mid- to late-nineteenth century. [4] Elizabeth Mayo's books Lessons on Objects and Lessons on shells, which were about object lessons and were published during the Victorian Era, were revolutionary as they were the first to explain education to infant teachers.
A teaching method is a set of principles and methods used by teachers to enable student learning. These strategies are determined partly by the subject matter to be taught, partly by the relative expertise of the learners, and partly by constraints caused by the learning environment. [ 1 ]
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Directional solidification is the preferred technique for casting high temperature nickel-based superalloys that are used in turbine engines of aircraft. Some microstructural problems such as coarse dendritic structure, long dendrite side branches, and porosity hinder the full potential of single crystal ni-based alloys. [ 6 ]