Papers by Keyword: Phase Distribution

Abstract: Cement is frequently utilized in the building business across the world, and experts are currently looking for an acceptable and usable unused product that would substantially reduce cement consumption and production costs. Eggshell is one of the waste materials created by the chicken egg industry, and its production has been gradually rising in recent years, adding to environmental and disposal concerns. The chicken eggshell is a bio-ceramic composite that is a solid waste material whose final disposal is complicated and expensive. Following that, the presence of organic egg shells in the form of calcium carbonate improves the self-compacting capabilities of concrete and increases particle packing and spacer effects. The aim of this paper is to evaluate the mechanical characteristics of bio-cement eggshell composites, investigate the microstructure of eggshells by scanning emission microscope (SEM) and determine the phase distribution of eggshell composites by using x-ray diffraction (XRD).

Abstract: The T-junction model is simulated in Fluent by changing the curvature of branch pipe, and then the distribution characteristics of the annular flow was studied in T-junction distributor. The mass flow and pressure of the annular flow in this T-junction are studied, and the impact of Coanda Effect on the annular flow distribution characteristic is analyzed in oil-air two phases flow. The results show that, Coanda Effect affects the distribution of oil-air annular flow unevenly. The mass flow rate of air phase and the air velocity of outlet increase with decreasing the curvature, while the mass flow rate of liquid decrease with decreasing the curvature of the branch pipe connection; T-shaped junction inlet pressure is high, but the pressure gradient is small, the pressure gradient in the small curvature manifold is larger than that in the large curvature manifold.

Abstract: A simulation of realistic samples within a neutron scattering or imaging experiment has been created in order to support the accuracy, feasibility and analysis of residual stress measurements as well as the development of novel experimental methods and instrument components. Covering the influences of individual neutron instrument parameters, the simulation also assists in optimizing the experimental configuration towards precise measurements and effective usage of neutron beamtime.

Abstract: Based on the phase distribution which is defined in this paper, a new classification algorithm of M-ary phase shift keying (PSK) signals is proposed. To classify the modulation type of the M-ary PSK signal, the phase distribution of the unclassified signal is calculated firstly, and then the characters of the signal modulation are extracted by computing the FFT of the phase distribution. Moreover, the method is improved in this paper that it is extended to MPSK baseband signals with frequency offset, and the calculation complexity is reduced. Simulation result shows that the accuracy rate of the classification of BPSK, QPSK and 8PSK signals can reach 98.5% when the symbol length is 500, SNR is 3dB, and 16PSK signals can also be well classified when the SNR improves to 9dB.

Abstract: A new method is proposed for mapping of phase distribution in electron holography. A stage-scanning system was used for moving the specimen to obtain a series of holograms with different specimen positions in a fixed electron-optics configuration. By applying a digital aperture which selects an area on holograms with different specimen positions, an interferogram of the specimen can be obtained directly without a complex reconstruction method such as the one using Fourier transformation. Experimental results for a Co particle demonstrated the practicability of this method.

Abstract: The vibration of sluice gate may lead to the damage of the hydraulic structure, based on the S-transform, the frequency and the phase distribution of the pulsating water pressure. The results show that as the water level increases, the frequency of the pulsating water pressure is small, the pulsating power acting on the bottom of the gate is decreasing, the components of frequency are rich, the power is wide, although the amplitude of frequency is decreasing, the whole power of pulsation is not changed; there is an obvious wave about the phase as the time changes, the phase distribution map is symmetry and periodically changes, and the velocity of wave may increase as the frequency increases.

Abstract: Phase-based Stereo Matching (PSM) is an efficient matching method in binocular stereo vision. It bases on correspondence points which have the same phase-distribution. Sine raster generating algorithm is a basic and important step in PSM study. This paper advances that using defocusing rectify-binary patterns (DRBP) method substituted the focusing-sinusoidal-patterns (FSP) method. It has following advantages: (1) No gamma correction is required; (2) The object illuminance measurement is not desired; (3) The influence of noise is minified. There are same phases distribution in correspond points of the pair matching lines by experiment analysis. The feasibility of using DRBP to generate sine raster in PSM is demonstrated.

Abstract: Formation of microstructure defects at the phase boundaries in TRIP steels was investigated with the aid of microstructure analysis on a TRIP steel crystal, which was grown by the Bridgman technique. The microstructure studies comprised scanning electron microscopy (SEM), X-ray diffraction (XRD), electron backscatter diffraction (EBSD), transmission electron microscopy (TEM) and transmission electron microscopy with high resolution (HRTEM). Initial XRD measurements revealed that the crystals under study consist of austenite and ferrite with extremely strong preferred orientations. Subsequent XRD pole figure measurements and EBSD scans have shown that the orientation relationship between austenite and ferrite can be described by the Nishiyama-Wassermann model. For a detailed description of the microstructure of the Bridgman crystal, the orientation distribution of crystallites within the individual phases was investigated using the XRD reciprocal space mapping and the rocking curve measurements. These experiments have shown that the density of microstructure defects is much lower in ferrite than in austenite. The direct information about the defect structures at the phase boundaries between austenite and ferrite was obtained from the TEM micrographs, which revealed complicated micro-twin structures at the boundaries between the neighbouring phases. HRTEM discovered very narrow stripes of ferrite embedded in austenite that were regarded as a source of the microstructure defects in austenite.

Abstract: A two-phase volume-averaging model developed for the simulation of the dynamic decomposition and solidification of hypermonotectic alloys was used to study the occurrence of convection phenomena during directional solidification of a hypermonotectic alloy (Al-10 wt.%Bi) under terrestrial condition. The model accounts for nucleation and growth of secondary phase droplets, Marangoni and Stokes forces, solute partitioning, heat release due to decomposition and solidification. It is shown that the appearance and growth of secondary droplets is accompanied with a continuous downwards motion of droplets, which rapidly becomes unstable. After relaxation of this dynamic motion the advancing solidification front freezes in the resulting non-uniform droplet distribution.

Abstract: The time-dependent distributions of temperature and stresses in a box-column welded from ultra thick plates with a center segregation were analyzed using the commercial finite element package SYSWELD+ for several types and angles of groove. The welding method used in the current study was SAW(submerged arc welding), which was initially simulated using the commercial finite element package MSC/MARC, combined with a user-defined subroutine, to identify the weld thermal cycle. The major points of investigation were the optimum type and angle of groove that would minimize the weld stress, especially at the center segregation. A nonlinear transient heat transfer analysis was accomplished. The thermal properties, i.e. conductivity and specific heat, were found to be temperature dependent, plus the effects arising from a phase change, convection, and radiation were also taken into account.