The sudden impact of gases at high pressures on the wall of blast hole causes the shock wave to be transmitted into the rock mass. The outgoing shock wave generates the fracture in the surrounding rocks, provided the intensity of the stress is greater than the dynamic compressive strength of rock (Hagan, 1973). It also develops radial fractures due to tangential and tensile stresses (Johansson and Persson, 1970). Upon meeting an open joint or a free face, the compressive stress wave gets reflected and spalling occurs if the intensity of the tensile wave exceeds the dynamic tensile strength of the rock (Hino, 1956; Duvall and Atchison, 1957). The reflections of the compressive wave generate tensile and shear waves, which may propagate through pre-existing cracks and further widens them apart (Fourney, 1993) due to the phase difference between the two wave types.
2) Curves are displaced to lower Er(t) level with increasing temperature. 9: Viscoelasticity creep: At constant stress level many polymers are disposed to time dependent deformation; such condition is called Viscoelasticity creep. This stipulation is noteworthy at room temperature under the stresses which are less the yield strength of the material. Creep consequences are representing as time needy creep modulus Ec (t) defined as Ec (t) =σ/e(t) σ = constant applied stress e(t) =time dependent strain • The creep modulus is temperature insightful. • Magnitude increase with time.
For uncoated compacts, it should disintegrate and no granules should be left in the disintegration apparatus more than 30 minutes (The United States of Pharmacopeia Convention, 2007). Evaluation of deformation properties of compacts Hackels and Kawakita equations (Equation 3 and 5) were used to assess the deformation properties of compacts (Zhang, Law, & Chakrabarti, 2003). Heckel’s equation: kP + A= ln〖1/(1-DA)〗…………………… (Equation 3) Where P is the compression pressure of compacts and DA is the relative density (Equation 4). DA = ρα/ρτ……………………………………………..……… (Equation 4) Where ρA is the apparent density compacts and ρT is the true density of a powder. The Heckle plots of ln〖1/(1-DA)〗 against P were established.
The decrease in protein solubility due to heat can impair the foaming and emulsion ability. As a consequence, raw taro flours exhibit relatively higher foaming capacity than the gelatinized ones. Further the foam capacity, foam stability, whippability are generally inferior compared to wheat flour. Addition of salt up to 2% concentration in the flour suspension increases the foam capacities of taro and wheat flours (Godoy et al., 1992). Blanching can affect on the swelling capacity of taro.
Reed and Wacker (1970) reported that bulk density and particle size have a significant effect on width and shape of the distribution pattern. Bhushan (1981) reported that high normal pressures and high sliding speeds can result in high interface (flash) temperatures that can significantly reduce the strength of most materials. He added that in some cases, localized surface melting reduces shear strength and friction drops to
The heat source causes highly non uniform temperature distributions across the joint and in the parent metals. Therefore, the thermal expansion and contraction during heating and subsequent cooling as well as material plastic deformation at elevated temperatures result in inevitable distortions and residual. [3] II. WELDING DISTORTION & CONTROL METHOD Distortion in a welded structure results from the non-uniform expansion and contraction of the weld metal and adjacent base metal during the heating and cooling cycle of the welding process. During heating and cooling in the welding process, thermal strain occurs in the weld metal and base metal near the welded zone.
4) To experimentally evaluate the effect of mixed, forced and free convection on the particle drying, Heat transfer, and pressure drop. 5) To determine the effect of direct or indirect solar heating method on the drying efficiency. Methodology The solar thermal energy availability would be evaluated from the available solar data and the appropriate solar collecting method would be determined. Solar enhanced fluidized bed dryer would be Designed Fabricated and installed. The fluidized bed would be designed in such a way that the orifice plate and product inlets are replaceable, so as to study the effect of different types of air distributor on the drying efficiency.
Material Preparation: Material preparation and drying parameters have a particularly important influence on the quality of the finished product as well as lowering the rejection rates. Moisture can cause hydrostatic degradation of polymer during processing and shows up as streaks or small bubbles on the surface. The PC should have a residual moisture content no more than 0.02 %. It is dried at approximately 120°C for about 3 to 4 hours for high speed dryers and 2-3 Hours for dry air dryers before molding to ensure optimum processing, appearance and mechanical properties. Lower temperatures do not ensure sufficient level of drying and at higher temperature; there is risk of granules sticking together and being non suitable for
[3] concluded that interface friction resulted in tremendous plastic deformation, which was beneficial for joint formation. Ni and Ye [4] found that very fine grain (～4.2 μm) distribution at the weld interface. However, the mechanism of ultrasonic welding is not clear due to the weld process was complicated dynamic process, and the influence of ultrasonic soften of materials on temperature rise and materials plastic deformation are not comprehensively understood by experiments study alone. Finite element method (FEM) can be used in simulate the physic phenomenon in the dynamic process, and was widely used in recent study. In the earlier simulations, the ultrasonic softening of materials is not considered in their models.
High rate of pouring might cause turbulence but slow rate of pouring might also cause the material to solidify even before the mold has been fully filled with the material (Bilal n.d). The pouring temperature, defined as the initial temperature of the material before it is poured into the mold, must be higher than the solidification temperature of the said material (Bilal n.d.) Fluidity, which is defined as the capability of the material to flow into the mold before solidification also affect the quality of cast products since it plays a key role in the ability of the material to completely fill the regions of the mold before the material solidifies. Some of the factors that affect fluidity include: temperature, material composition, heat transfer to the environment and