Shrinkage factor affecting

Several factors affect the magnitude of drying shrinkage ... 

The metal yield is the ratio of the amount of metal melted to the weight of the finished good castings. Five main factors affect metal yield, i.e. quality requirement choice of mould-box size the extent of runner and feeder systems metal shrinkage scrap casting rate. 

The mechanism of irreversible shrinkage is not clear there are presumably all the factors affecting shrinkage involved. The decreasing distance between the gel particles may be considered as irreversible, because it leads to the reduction of free energy of the system. The effect of different factors on irreversible shrinkage is shown in Fig. 5.57. 

The objectives of mixing additives with soil are to improve volume stability, strength and stress-strain properties, permeability and durability. In clay soils, swelling and shrinkage can be reduced. Good mixing of stabilizers with soil is the most important factor affecting the quality of results. Cement and lime are the two most commonly used additives. 

When undulations exist in the TGO, the thermal misfit stresses will redistribute around these sites. Tensile stresses are induced normal to the TGO/bond coat interface, as well as in the TBC [6, 66, 67], As a consequence, cracks nucleate and grow around these locations. The coalescence of these cracks leads to TBC failure, as shown schematically in Fig.9B. Two factors affect the rumpling of the TGO (a) local volume shrinkage induced by transformation of P-(Ni,Pt)Al to y -Ni3Al or y-Ni (b) the visco-plastic deformation of the bond coat in order to release the growth stress or thermal misfit stress during thermal cycling. 

ACI 209.1R-05 Guide to Factors Affecting Shrinkage and Creep of Hardened Concrete. 

Several factors affect part shrinkage, including the temperature of the melt and mould, injection pressures and time, as well as the mould design. Although shrinkage can be anisotropic, most LCPs exhibit exceptional dimensional stability. Dimensional changes as low as 0.015% have been measured on unannealed specimens after exposure at 125 °C for 24 h. 

Although there are some anomalies in the literature, it is generally agreed that both types of volume deformation are a function of the same fundamental mechanism and that the influence of other factors such as admixtures will affect both shrinkage and creep in a similar manner. As outlined earlier, water-reducing admixtures can be used to obtain different effects on the plastic/hardened concrete and it is this factor, together with the admixture type, that is important in determining the effect on the volume deformations of concrete. 

---