Ceramics and cements are the best examples of brittle fracture. Ductile fracture is better than brittle fracture, because ductile fracture occurs over a period of time, while brittle fracture is fast, and can take place at lower stress levels than a ductile fracture. Ductile fracture involves plastic deformation in the area of an advancing crack, and is a slow process. b) Fatigue: It is defined as
The rate of cooling is immaterial except for some steels which are susceptible to temper brittleness. As the tempering is increased, the martensite of hardened steel passes through stages of tempered martensite and is gradually changed into a structure consisting of spheroids or cementite in a matrix of ferrite, formerly termed as sorbite. These changes are accompanied by a decreasing hardness and increasing toughness. The tempering temperature depends upon the desired properties and the purpose for which the steel is to be used. If considerable hardness is necessary then the tempering temperature needs to be low.
Introduction Quenching is one of the most important heat treatment process to attain desirable properties, for example strength and hardness. Quenching means to rapidly cool a material. But this rapid cooling can cause some serious distortions in the material. In steels, the transformation phases and thermal gradients are the main causes of this distortion. It has become an industry objective to reduce this distortion caused by heat treatments.
Plastic shrinkage crack may not affect the strength of structure but will ruin the appearance of the structure and the crack to full depth may allow water to penetrate it. Figure 9. Plastic Shrinkage Crack Figure 9 is a representation of plastic shrinkage crack where crack propagation is highly evident. There are several ways to minimize this crack such as in hot weather, lower the temperature of the fresh concrete by using chilled mixing water or replacing some of this water with crushed ice. Covering the concreted area to avoid excess evaporation or proper curing can help reduce this crack formation.
The tensile strength of the material increases because the subsequent application of tensile stress must nullify the compressive prestress. • This can result in improved structural capacity and serviceability compared to conventionally reinforced concrete. • High-strength tendons are used to produce compression. They are made of high- tensile steels, carbon fibers etc. and consist of threaded bars, single or multiple
Drilling a gap in concrete is a helpful and convenient strategy. You can set up racks, hang artistic creations, introduce lights, and do significantly more rapidly and securely. The procedure itself is straightforward, however choosing the correct devices and seeing how to utilize them will spare you a colossal measure of time. Setting Up Hammer drill Drilling concrete is substantially less demanding with a hammer drill, or a revolving hammer for huge occupations. These instruments crack the solid through fast hammering and afterward drill to scoop out the broken material.
Finally, tensile properties are often used to predict the behavior of a material under forms of loading other than uniaxial tension. Tensile specimens: First, tensile specimens have to have shoulders or thick part in both ends because of gripping. Moreover, the most important part in specimens are the gage section, the cross-sectional area of the gage section is reduced base on deformation and future which supposed to happen in this area. Then The distances between the ends of the gage section and the shoulders should be great enough so that the larger ends do not constrain deformation within the gage section, and the gage length should be great relative to its diameter. Otherwise, the stress state will be more complex than simple tension.
The question still remains whether Underbalance really is the best choice or otherwise just another method with flaws and disadvantages. Therefore, the Underbalanced upside can be seen through three main aspects which are the avoidance of formation damage, the increase in productivity and the amount of cost saved while performing this method. The main and most important reason why Underbalanced Drilling was needed is to prevent and minimize the reservoir damage. Reservoir damage in this context means the damage done through the invasion of drilling fluid into the reservoir rock. This happens due to the high pressure of overbalanced drilling in the wellbore as it forces the drilling fluid into the pores of reservoir rocks that are being drilled.
Even though cooling crystallization and anti-solvent crystallization are convenient, it has major drawbacks in terms of slow rate of crystallization, high supersaturation degree , solvent and anti-solvent selection based on solubility. Some of the newer methods for crystallization include ultrasound assisted (UA) cooling crystallization , UA anti-solvent crystallization  and melt sonocrystallization , . Ultrasound based approach has been found to initiate nucleation at lower supersaturation. Reduction in induction time has been observed in most of the APIs when the supersaturated solution is subjected to ultrasonic irradiation
The speed of any wave depends upon the properties of the medium through which the wave is traveling. Typically there are two essential types of properties that affect wave speed - inertial properties and elastic properties. Elastic properties are those properties related to the tendency of a material to maintain its shape and not deform whenever a force or stress is applied to it. A material such as steel will experience a very small deformation of shape (and dimension) when a stress is applied to it. Steel is a rigid material with a high elasticity.