Preparation of Sub-Micron Bi Alloy Powers with the Ultrasonic Mixed Crushing

2021 ◽  
Vol 1035 ◽  
pp. 217-226
Author(s):  
Qiao Xia Zhang ◽  
Jing Tao Shi
Keyword(s):  
Mechanical Properties ◽  
Shock Wave ◽  
Melting Point ◽  
Wave Theory ◽  
Cast State ◽  
Bulk Materials ◽  
Ultrasonic Atomization ◽  
Shock Wave Theory ◽  
Submicron Powder ◽  
Sintered Materials

The powders of the BiInSn alloy were produced by the ultrasonic atomization and the ultrasonic mixed crushing using the different dispersants. In this study, the composition, microstructure, melting point, and size of these powders were observed. The viscosity of different solutions of the dispersants and the mechanical properties of the sintered bulk materials were also tested. From the data analysis and results, we found that the composition of the powders using the different methods was consistent with the as-cast state. In addition, the size of powder produced by ultrasonic mixed crushing was significantly smaller than that ultrasonic atomization. And during the ultrasonic crushing process, with the increase of the viscosity of the dispersant, the size of the final powder also decreased, and even submicron powder were produced. The product of submicron powder could effectively improve the density and mechanical properties of sintered materials. And the principles of ultrasonic atomization and ultrasonic mixed crushing were discussed. We found that the mechanism of ultrasonic mixed crushing to produce powder was the micro-shock-wave theory of ultrasonic cavitation. At the same time, these dispersants were effective in keeping the droplets separate from each other and preventing them from merging back into the larger droplets. The droplet was solidified into a powder by rapid cooling in the end.

Destruction Analysis of Broadside Multi-Cabin Protective Structure of Warship under Explosion Loading

2013 ◽  
Vol 395-396 ◽  
pp. 866-870
Author(s):  
Long Guang Jiang ◽  
Xiao Dong Zhang
Keyword(s):  
Shock Wave ◽  
Wave Attenuation ◽  
Wave Theory ◽  
Protective Structure ◽  
Naval Vessel ◽  
Reflected Shock ◽  
Defensive Structure ◽  
Explosion Loading ◽  
Shock Wave Theory ◽  
Extent Of Damage

Shock wave parameters of cabins for shipboard defensive structure are studied based on shock wave theory. The destroy of defensive structure can be estimated by impulse of shock wave. In the process of air shock wave propagating, isentropic suction wave is reflected from void cabin into defense structure. The solution of shock wave attenuation of void cabin can be reached by using isentropic line to replace the shock adiabatic of the reflected shock. It can be seen from the example that the multi-layers defense structure system of warship is very important to decrease the damage from explosive shock wave. The method can be used to predict the extent of damage of naval vessel.

An application of shock wave theory to traffic signal control

1981 ◽  
Vol 15 (1) ◽  
pp. 35-51 ◽  
Author(s):  
Panos G. Michalopoulos ◽  
Gregory Stephanopoulos ◽  
George Stephanopoulos
Keyword(s):  
Shock Wave ◽  
Wave Theory ◽  
Traffic Signal ◽  
Signal Control ◽  
Traffic Signal Control ◽  
Shock Wave Theory

scholarly journals Herbig-Haro Objects

1977 ◽  
Vol 42 ◽  
pp. 1-24
Author(s):  
K.H. Böhm
Keyword(s):  
Shock Wave ◽  
Geometrical Structure ◽  
Wave Theory ◽  
Theoretical Models ◽  
Emission Lines ◽  
Low Density ◽  
Line Formation ◽  
Line Profiles ◽  
Apparent Paradox ◽  
Shock Wave Theory

The available observational information on the geometrical structure, emission line and continuous spectra, line profiles, radial velocities and linear polarization of Herbig-Haro objects is briefly reviewed. We emphasize the inhomogeneous structure of the “classical” Herbig-Haro objects and the appearance of small “condensations” with radii of ~300-900 a.u. The apparent paradox of the presence of “gaseous nebula type” as well as “reflection type” Herbig-Haro objects is discussed.A purelyempiricalmodel of the regions of line formation is discussed. It shows that regions of low density (Ne~103cm-3) cover the space between the condensations and most of the volume of the condensations themselves. Only between 0.1 and 1% of the volume of the condensations is covered by a high density medium (Ne~ 4 x 104cm-3, N ~105cm-3) which, however, contributes very strongly to the formation of the spectrum.Differenttheoretical modelsfor the line forming regions are discussed. We strongly favor the shock wave theory in which the emission lines are formed in the cooling regions of (running) shock waves. The general agreement between observations and the new calculations by Raymond is emphasized, and the few remaining discrepancies are discussed. The possibilities of explaining other properties of Herbig-Haro objects (including time scales, sizes and filling factors of condensations) are described.

scholarly journals On the Formation of Interstellar Gas Clouds

1958 ◽  
Vol 8 ◽  
pp. 943-943
Author(s):  
S. A. Kaplan
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Wave Theory ◽  
Density Fluctuations ◽  
Interstellar Space ◽  
Interstellar Gas ◽  
Degree Of Ionization ◽  
Great Density ◽  
Characteristic Features ◽  
Shock Wave Theory

The characteristic features of interstellar gas clouds—existence of large density fluctuations, their connection with cosmic dust, stretching along the magnetic fields, and so on—may be described by a shock wave theory in interstellar space.The author has developed a theory of stationary shock waves accompanied by losses of energy by means of radiation. Choosing two surfaces on both sides of the front, so that the regions of energy radiation should lie between them, we can write an equation for the mass flow and for the impulse conservation between these surfaces, and two equations which determine the stationary temperature of the gas in the field of interstellar radiation. The solution of this system of equations permits one to determine the general changes of thermodynamic and other parameters for the transition of gas through the shock wave with regions of radiative cooling. If changes of the degree of ionization take place, and a magnetic field is present, some terms should necessarily be added to the corresponding equations.The boundary between the interstellar gas cloud and the intercloud medium must represent the shock wave accompanied by losses of energy by means of radiation, because such ruptures may probably be supposed as the sole explanation of stability of the great density changes (a hundred times and more) often observed in the interstellar space.In this paper we give some results of the theory of shock waves accompanied by radiative losses of energy.

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