The cupola is the classical iron melting unit and is stil the most widely used primary melting unit for iron production due to its simplicity, reliablity and the flexibility in the quality of charge materials that can be used because some refining of undesireable elements such as zinc and lead can be achieved. While the cupola is an efficient primary melting unit, it does not adapt easily to varying demands nor is it an efficient furnace for superheating iron. For this reason it is often used in conjunction with an electric duplex furnace.
The simplest form is the cold blast cupola which uses ambient temperature air to burn the coke fuel. The metal temperature that can be achieved is normally form 1350 to 1450 C but higher temperatures can be achieved through the use of divided blast or oxygen enrichment.
(Foseco ferrous foundryman's handbook, John R. Brown, pg. 40)
Shell Mold Casting:
In shell mold casting, molten metal is poured in to a shell of resin-bonded sand only 0,4-0,8in.
(10 to 20mm) thick. The mold is formed by introducing the chemically coated sand to a heated
pattern that thermally cures the bond. By controlling the core bond temperature and cycle, the
depth of cure can be controlled to the desired thickness. Cured mold sections are removed and
assembled for pouring, usually baked by unbonded or green sand. Shell mold castings surpass
ordinary sand casting in surface finishand dimensional accuracy and cool at slightly higher rates;
however, equipment and production costs are higher and the size and complexicity of castings
that can be produced are limited.
(Aluminum alloy castings: properties, processes, and applications, John Gilbert
Kaufman,Elwin L. Rooy,American Foundry Society, pg. 25)
NURBS Surfaces:
Deformable objects have been considered as important to virtual reality applications, as they
may model clothing, facial expression, human and animal characters. In particular,Non-Uniform
Rational B-Splines (NURBS) [4, 16] are often employed to represent such objects as they can be
used to produce a variety of shapes simply by manipulating their control points and weights.
However, NURBS surfaces are seldom used in interactive applications that demand realtime
rendering performance because of their high rendering cost. There have been a lot of work carried
out to address this problem. Most of the methods developed are based on tessellation
[1, 6, 8, 9, 10, 17]. This tessellation process subdivides the NURBS surfaces into polygons so that
the hardware graphics accelerator, if present, may render the polygons in real-time. However,
this process is computationally very expensive. As a NURBS surface is deforming, this process
must be executed in each frame to reflect the change of the object shape. Since in many real-time
applications such as computer games, we may want to have many deformable objects in the
environment. Existing rendering methods would be difficult to render these objects in real-time.
(Incremental Rendering of Deformable Trimmed NURBS Surfaces, Gary K. L. Cheung, Rynson
W.H. Lau, Frederick W.B. L, pg. 48)
Vibration (vibratory) Stress Relief:
Welding process inevitably induce residual stress into welded structures. This creates potential problems in terms of dimensional stability and structural integrity. Traditionally post weld heat treatment (PWHT) was used to relieve residual stress, which is an effective process, but it suffers from a number of disadventeges: oxidizing the heating surface and changing mechanical properties of materials. Vibratory stress relief has been proposed as an alternative to relieve wel residual stress for many years. Significant residual stress reduction is achieved in a labratory environment by applying large vibration amplitudes. But the importance of the structure resonance on the vibration stres relief was not paid enough attentions, which is critical for relieving residual stress for large structures because the required vibration amplitude is too big. Because of lack of understanding that technique, vibration stress relief is not using in industrial areas oftenly.
(Trends in welding research: proceedings of the 7th International Conference,
Stan A. David,ASM International, pg. 1)
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