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This widespread application is due to the toughness and strength, caused by the precipitation of copper, that are exhibited even at elevated temperatures which other fine-grained structural steels have at room temperature.
Studies of the cycle calculations including the number of preheaters have indicated that there is an optimum plant efficiency using feed water (FW) temperatures at approximately 340 °C [1, 6].
In Europe it has been a common practice for more than 30 years to use the material 15NiCuMoNb5-6-4 (also known as EN-WB 36, the material designation and trade name of company Thyssen Schulte Werkstoffe GMBH-Dusseldorf- Germany, material number 1.6368) for this purpose.
The main reason for the widespread application of this material is that, even at elevated temperatures, it has the toughness and strength which other fine-grained structural steels have at room temperature.
If the number and size of the copper precipitates change during operation of a component or due to exposure to higher temperature, a change of the residual-stress level occurs, ultimately the chances of failure increase.

And it quantitatively analyzes and valuates the stability of number 2 and 17 single dangerous rock by means of planar slide method and analysis of engineering geology respectively.
Studies show that number 2 is in an unstable state and number 17 is in a stable state.
On the top, it is made of gray to gray layer medium to fine-grained quartzose sandstone and purple sand shale, ranging from 0.8 to 1.0m sandstones and 2.6 to 3.0m sand shale.
At the middle, it is made of grey to light grey thick layered to fine-grained quartzose sandstone, obviously below rao bowl top, giving rise to a escarpment at the thickness of 12 to 15m.

A recent work hardening model developed by Nes and co-workers at NTNU, Trondheim provides a unified theory for warm and cold stress-strain behaviour which in principle accounts for alloy aspects such as effect of dispersoids (size and number density) and solute content, including dynamic strain aging for Mg containing aluminium alloys.
The ALFLOW model expresses the critical resolved shear stress of slip within a grain as a function of the microstructure and size of that grain. )/1/1( ˆ 2 1 D Gb Gb iptat + + ++=+= δαρατττττ (1) Here aτˆ characterizes the rate and temperature independent interactions due to long-range elastic stresses, while the component τt characterises the rate and temperature dependent interactions with short-range obstacles, τp is the stress contribution due to non-deformable particles (dispersoids), α1 and α2 are constants, G is the shear modulus, b is the Burgers vector, δ and D are the cell/sub-grain size and grain size respectively.
Considering solute containing alloys, the rate-controlling reaction for receovery is assumed to be cross-slip where the dynamic recovery terms, i.e. the one for cell-interior dislocations (Eq. 3) and the one for sub-grain growth (Eq. 4), depend on the amount of solute through activation volumes related to the annihilation of network dislocations and growth of sub-grains, respectively.

Atomic Force Microscope (AFM) was used to characterize the film surface morphology, finding that the B1.08FO film prepared in Si substrate was denser while grain size and surface roughness were smaller.
By comparing the XRD pattern of B1.05FO and B1.08FO, when we increase the content of Bi, the number of impurity phases reduces.
As BFO films go through rapid thermal process after sputtering in Si substrate, temperature rise and cooling period is rapid , accounting for the result that grain of both films are not fully developed which leads to the small grain size of films.
The grain size of B1.05FO is bigger than 100nm, while the B1.08FO is about 100nm.
AFM was used to characterize the film surface morphology, and it is found that the B1.08FO film prepared on Si substrate was denser while the grain size and surface roughness were smaller.

The third is to describe briefly the effort the author is involved in in modeling explosives ignition at the grain scale.
The rationale is that the door way modes are excited by a small number of phonons and aid the up-pumping process.
Meso-Scale Modeling (Grain Scale) It’s been long felt that the question of explosives ignition, be it by shock or other mechanical insults, must be understood ultimately at the grain scale where the material exhibits, as illustrated in Fig. 1, a complex stochastic heterogeneous structure.
Direct grain scale simulations.
Ignition Probability/Kinetics • Size/mass (ignition) • Intensity/temperature (ignition) • Number/proximity (growth/coalescence • Mass

Equally, the pore de-percolation process is sensitive to cement grain dispersion [7].
In He [13] some shape simulation strategies were proposed for particles used in concrete, i.e., aggregate as well as cement grains.
Fig. 8 presents data on the depercolation process that a particular cement paste (Blaine number 157, w/c=0.3) undergoes during hydration.
Since a large number of trials may be involved, generation of the complete tree system would be laborious.
The zones of increased connected porosity adjacent to the aggregate grain surfaces are significantly reduced (Fig. 13).

From the last two decades a number of research scholars reported the use of veritiy of heat treatments to tailor the properties of medium carbon steels.
Here the degree of dispersion of ferrite and cementite in pearlite increases to improve the machinability with finer grain size.
Specimen are polished with series of emery papers in the order of decreasing the grain size of grits and etched with Nital.
Figure 8 shows microstructure of S2 condition with 24 hours of Spheroidization time showing coarser spheroidal phases with lesser number of globules [6].
Microstructure of spheroidized specimen shows spheroids of carbides and lower Spheroidization temperature shows incomplete process with lesser number and diminished spheroids.

The in-situ tests in the SEM show the evolution of the microstructure in dependence on the deformation degree for uniaxial deformation and the number of cycles during fatigue, respectively.
With increasing total strain amplitudes the onset of the a'-martensite transformation is shifted to lower number of cycles [3].
During the in-situ deformation SEM micrographs were taken at certain strain intervals or number of cycles, respectively using the back-scatter electron (BSE) contrast in order to follow the formation of deformation bands, orientation changes and places of phase transformation.
The SEM micrographs show that deformation bands develop under an angle of 73° with respect to the loading axis (horizontal) crossing subgrain boundaries in a large austenitic grain.
(a) SEM micrographs of a large austenitic grain consisting of several subgrains taken at 4 different strain levels illustrating the development of deformation bands and strain localizations at subgrain boundaries.

The microstructure is typical of coarse dendritic grains with carbides, eutectic, and shrinkage pores.
Results and discussion The microstructure of cast IN738LC is typical of coarse dendritic grains with carbides, eutectic, and shrinkage pores.
The scatter in measured data can be related to the large scatter in Young´s modulus due to coarse-grained dendritic microstructure.
With an increase in the temperature, the number of initiation sites slightly increased (Fig. 7c).
Straining with 0.5 % deformation resulted in a significantly higher number of initiation sites (Fig. 7c, d).

Microstructural Changes Grain Refinement: ERW results in a refined microstructure characterized by smaller grain sizes, which enhances mechanical properties.
Fig. 6 a) CT image for end assembly with retaining bushing The striation area seen in the images is the result of resistance electric welding of the pipe end cap, a process that can generate a number of mechanical problems, particularly in terms of mechanical stress concentration.
The effects of the presence of carburization at the grain boundaries: Brittle structure: Carburization at grain boundaries tend to create a more brittle structure.
This occurs when cracks propagate along grain boundaries, weakening the overall structure.
Microstructure aspect Grain size and shape: The grains are fairly well defined, but their sizes appear slightly uneven.