A method is presented to use a dimensionless form of the well-known Niyama criterion to directly predict the amount of shrinkage porosity that forms during solidification of metal alloy castings. The main advancement offered by this method is that it avoids the need to know the threshold Niyama value below which shrinkage porosity forms; such threshold values are generally unknown and alloy dep...

In a foundry casting line, contaminants are released from a large area. Casting fumes include both volatile and particulate compounds. The volatile fraction contains hydrocarbons, whereas the particulate fraction mostly comprises a mixture of vaporized metal fumes. Casting fumes lower the air quality in foundries. The design of local ventilation for the casting area is a challenging task, becau...

Ice templating, also known as freeze casting, is a popular shaping route for macroporous materials. Over the past 15 years, it has been widely applied to various classes of materials, and in particular ceramics. Many formulation and process parameters, often interdependent, affect the outcome. It is thus difficult to understand the various relationships between these parameters from isolated st...

Porous ceramic materials are currently used as volumetric sunlight absorbers in concentrating solar power systems. As the efficiency of thermodynamic cycles rapidly increases with the operating temperature, the favorable characteristics of so-called ultra-high temperature ceramics (UHTCs) can be successfully exploited in novel solar absorbers. The present work reports, for the first time to the...

Ice-templating techniques, including freeze-drying and freeze casting, are extremely versatile and can be used with a variety of materials systems. The process relies on the freezing of a water based solution. During freezing, ice nucleates within the solution and concentrates the solute in the regions between the growing crystals. Once the ice is removed via sublimation, the solute remains in ...

Natural and synthetic hydroxyapatite (HA) scaffolds for potential load-bearing bone implants were fabricated by two methods. The natural scaffolds were formed by heating bovine cancellous bone at 1325°C, which removed the organic and sintered the HA. The synthetic scaffolds were prepared by freeze-casting HA powders, using different solid loadings (20–35 vol.%) and cooling rates (1–10°C/min). B...

The technique of monolayer freeze-fracture autoradiography (MONOFARG) has been developed and the principles, quantitation, and application of the method are described. Cell monolayers attached to polylysine-treated glass were freeze-fractured, shadowed, and coated with dry, Parlodion-supported Ilford L4 photographic emulsion at room temperature. Quantitative aspects of MONOFARG were examined us...

We present a novel acceleration technique for the volume ray casting process used in virtual colonoscopy. Our method exploits the information obtained from casting a ray to avoid redundant computations for neighbouring rays. A corridor from the image plane into the volume data set is examined whenever a ray is cast. All rays passing through this corridor reach the same cell as the first non-spa...

Introduction: Congenital Talipes Equinovarus (CTEV) is a common congenital foot deformity that is associated with long term disability. Treatment with Ponseti method has been successful especially for children who present early. We conducted this study to investigate the age of presentation of children and report the early outcome. Materials: This is a retrospective study from a single institut...

This paper describes a simple method for the freeze-fracturing of cells in monolayers or multi-layer tissue cultures. The method produces high quality replicas and is applicable to the study of virtually any tissue culture or organ culture system. It uses standard materials and equipment for both tissue culture and freeze-fracturing.