Characterization And Classification On Ultrasound Signals Using Dct Transformation

Usually bond two dissimilar metals are joined using this process of welding, especially to weld one metal over a base metal extending to large areas. Production of corrosion free sheets and plate stock for making processing equipment for different operations in the chemical industries and petroleum industries are the major applications. Explosion welding general requires no filling metals, and external agencies for production of heat are also not required. Diffusion does not occur during the processes. The metal parts are metallurgically bonded, in many cases it results in a mechanical interlocking that is occurred as locking formed by a rippled or wavy interfaces between the surface of metals. The process of welding one metal plate on another can be described with help of Figure

Shape memory alloys (SMA) have attracted much attention in recent years, since they are smart (or intelligent) materials, as well as functional materials, which already exist. These alloys possess the characteristics of the shape memory effect (SME) and super-elasticity (SE) which are caused by the martensitic (or displacive) transformation (MT) and its reverse transformation to the parent austenite phase; we define the characteristic transformation temperatures as follows;

Ultrasound imaging has been considered as one of the most powerful techniques for imaging organs and soft tissue structures in the human body. However, the presence of random speckle noise makes human interpretation and computer-aided ultrasound image diagnosis a highly difficult task. Thus it is necessary that we remove speckle noise from the images before they are processed further.

Cast Iron and Steel are ferrous alloys – means iron is their prime constituent. In cast iron the carbon content is higher than steel. In most of the cast irons carbon exists as graphite. Graphite formation is regulated by the composition and rate of cooling. Silicon concentration greater than about 1 wt% and slower cooling rates during solidification of liquid cast iron favor graphitization. On the other hand, steels are iron-carbon alloys that may contain appreciable concentration of other alloying elements. There are thousands of steel alloys that have different compositions and/or heat treatments. Classification of ferrous alloys is shown below.

Alloys are often made in order to alter the mechanical properties of the base metal, to induce hardness, toughness, ductility, or other desired properties. While most metals and alloys can be work hardened by inducing defects in their crystal structure, caused by plastic deformation, some alloys can also have their properties altered by heat treatment. Nearly all metals can be softened by annealing, which repairs the crystal defects, but not as many can be hardened by controlled heating and cooling. Many alloys of aluminum, copper, magnesium, titanium, and nickel can be strengthened to some degree by some method of heat treatment, but few respond to this to the same degree that steel does.

The design of new stainless steel alloys with novel physical properties is vital to the petroleum industry in order to develop technologies which will perform more efficiently at high temperatures and pressures. While stainless steels with the addition of nickel have mechanical and thermal properties which are desirable at high temperatures and pressures, the high cost of nickel is prohibitive towards development of new devices which can be used in harsh conditions, so discovering stainless steel alloys with similar properties with little to no nickel content with be ideal. Ferritic alloys (Fe-Cr) already have some applications in high temperatures in the presence of sulfur, but they generally have poor tensile properties. The addition of

The direct deposition of Ti64 onto a 410 grade stainless steel base plate resulted in a very fine microstructure which transitions into a coarser one towards the Ti64 layer, as seen in Figure 1. FeTi intermetallics are commonly form during traditional fusion welding, as well as diffusion bonding of Ti based and Fe based alloy [1-5]. Microstructure along the interface seen in the current study was similar to that obtained by diffusion bonding of micro duplex steel to Ti64 alloy by Orhan et al. [30]. A crack is visible in the figure, which is representative of the entire bonded region. We hypothesize that cracking occurred due to residual stresses brought about by the differences in thermal properties between the two materials. Similar

The global demand for clean steel has increased in the last years due to the demand for better performance. There is need to develop steel with fewer inclusions to improve performance. Steel inclusions impede performance as they may act as sources of crack growth and propagation. Some inclusions affect steel properties such as fatigue, ductility and weldability. According to Riyahimalayeri et al. oxide inclusions reduce the rolling contact fatigue life of steel products even when the total oxygen content is below the 10 ppm (Riyahimalayeri, et al., 2013). Inclusions like sulphur reduce steel toughness which hinders performance. It is imperative to develop methods that are aimed at reducing steel inclusions for better performance. Improved steel cleanness

Alloys In austenitic grades, carbon is usually kept to low levels (C < 0.08%). Chromium content ranges from 16.00 to 28.00% and nickel content ranges from 3.50 to 32.00%. This chemical composition allows them to maintain an austenitic structure from cryogenic temperatures up to the melting point of the alloy. These alloys cannot be hardened through heat treatment. The key properties of these types of stainless steel are excellent corrosion resistance, ductility and

(1) Previous experimental results indicate that the amount of η-Ni3Al0.5Nb0.5 phase can significantly affect the DFCGR property of AA alloy. The η-Ni3Al0.5Nb0.5 phase mainly plays a role of pinning grain boundary and retarding the intergranular diffusion of oxygen. Thus, the crack growth at grain boundaries can be retarded, and the notch sensitivity of the alloy can be avoided. Therefore, more the η-Ni3Al0.5Nb0.5 phase, the fatigue crack growth rate of the alloy can be reduced favourably. Figure 1 shows that the amount and morphology of η-Ni3Al0.5Nb0.5 phase precipitated from AA alloy with different grain sizes are different under the same thermal treatments. With decreasing grain size, both the grain boundary area of the alloy and the amount of η-Ni3Al0.5Nb0.5 phase increase, and the ability of grain boundary pinning and grain boundary oxygen diffusion retarding are significantly enhanced, thus the fatigue crack growth rate will reduce

By Tribuvan Kumar Prakash Bachelor of Engineering in Electronics and Communication Engineering Visveswaraiah Technological University, Karnataka, 2004. August 2007

Steel is an alloy of iron, with carbon being the primary solute in the solid solution. It is a polycrystalline solid with grain diameter from 10 to 20 micro-meter (Ashby et al). The presence of impurity like carbon causes the crystal lattice distortions to increase, hence making giving steel better hardness, yield strength, and tensile strength, at the cost of ductility. Pure iron being very ductile but comparatively weak, steel is widely because of its greater load bearing capacity. Other impurities are also introduced into steel to produce different properties. Materials like chromium, vanadium, titanium, boron etc. are added to steel to give it better corrosion resistance, hardness, tensile strength and better fatigue response (Smith et al). Elements like carbon and nitrogen form take up interstitial spaces between the iron atoms owing to their reduced atomic size (Smith et al). Elements with larger atoms like nickel, chromium, aluminium, sulphur, phosphorus etc. act as substitutional elements (Smith et al). Although, the inclusion of various alloying elements do alter the material property and the crystalline structure, material property of basic steel can be understood by analyzing various phases of iron and carbon solid solution. Considering the structural differences in steel it can be differentiated into austentic, ferretic and martensitic.

In the present research work rolled plates of Martensitic stainless steel (AISI 410 SS) were cut to length from the flats and each plate was cut to dimensions length 200mm, width 75mm and thickness 5mm. During welding of the base plates metallurgically compatible filler wire AISI 410 SS was used to fill the groove volume. AISI 304L SS solid filler wire was used for giving root pass for each plate and the welding parameters for giving root pass were kept same for each joints. The composition of base metal and filler wires is shown in Table 1.

The Al-Zn-Mg series aluminium alloys (7xxx) are the heat treatable alloys and widely applied as large structural components in navigation and transportation facilities, due to good combination of hardness, high strength and fracture toughness [1-6]. The use of Sc (scandium) to achieve grain refinement has recently received great attention. The microstructures and properties of aluminium alloys are strongly affected by adding small quantities of scandium. Scandium additions in excess of 0.55wt.% (i.e., hypereutectic) are very effective in grain refinement, suggesting that the primary ScAl3 phase serves as an effective grain nucleant [7-9].

Mild Steel is one of the major construction materials used in the industries. Corrosion is one of the serious problem affecting ship, pipe line and aviation industries. It affects the body of ship and thickness of pipe and an Aeroplane wings, surface, between joints and fasteners With the increased utilization of this metal in the manufacturing and construction firms, one of the major problems encountered is the control of corrosion rate when exposed to different corrosive environments. Corrosion is a natural process that reduces the binding energy in metals with the end result involving a metal being oxidized as the bulk metal losses one or more electrons