Experimental investigations of oscillatory droplet deformations during liquid jet breakup are presented. Droplets are produced using a pinhole droplet generator. The droplet diameter is roughly 100μm, and the experiments are carried out using propanol-2. The droplets may be produced under atmospheric or under vacuum conditions. Oscillations occur due to initial deformations of the droplets shortly after their separation from the jet. Oscillatory motions of the fundamental mode and of higher order modes may occur during the disintegration of the liquid jet. The periodical production of the droplets leads to a periodical repetition of the oscillation processes, Therefore, the experimental method allows the observation and evaluation of each phase of the motion under quasi-steady conditions. Oscillation modes dominating the droplet deformations are determined by comparison of observed and calculated droplet shapes. Different regimes of the disintegration process are found to be dominated by different oscillation modes. It could be shown that, besides oscillations of the fundamental mode, oscillations dominated by the first higher order mode may occur due to merging of droplets of different size.
The influence of the mixed state of type II superconductor on magnetostatic wave (MSW) dispersion and absorption is theoretically investigated. The MSW characteristics are shown to depend on the relationship between the MSW a.c. field penetration depth into superconductor 1, wavelength λ and superconductor thickness b. The former is expressed in terms of an effective conductivity, which is strongly dependent on the d.c. vortex velocity vo due to a d.c. current. If vo exceeds the MSW phase velocity, instead of absorption of the wave, we have its amplification. The effect of d.c. voltage generation owing to the dragging of vortices by MSW is also studied.
A simple interpolation scheme neglecting doubly occupied states is established between insulating and metallic limits of the t-J model. The equation of motion is linearized by applying the mean field approximation. Self-consistent equations of d-wave superconducting states are given and 2Tc/t as a function of carrier density δ is calculated.
The effect of space potential well in sheet plasma on the resonance condition in isotope separation by means of ion cyclotron resonance method is elucidated numerically by computer simulation. It is found that the resonance frequency and minimum rf peak electric field increase monotonously with the increase of peak space potential well of sheet plasma.
The fatigue test device of Shape Memory Alloy wire was developed using the Peltier element of Bi2Te3 and Sb2Te3 for p type and Bi3Te3 and Sb2Se3 for n type. The measurements of Ti-Ni-Cu wire and rapidly solidified Ti-Ni and Ti-Ni-Cu were carried out by short cycle time of heating and cooling under stable temperature control. From the experiment, it was concluded that the elongation by plastic deformation caused the fatigue and degradation of Shape Memory Alloy.
As a method to measure fluid pressure, it is known to detect the displacement of a diaphragm electrically. However we must pay attention to measure the data under the condition of bad environment electrically and take steps to eliminate electrical noise if it is existed. We conceived of the method to detect the displacement of a diaphragm optically with adopting newly developed our original special filter. We developed optical pressure sensor system using optical fiber for signal transmission lines, and evaluated its ability.
“In-Rotating-Water Spinning” process is a useful technique which can obtain directly the continuous wires having circular cross-section by injecting molten metal jet into a rotating water layer, and further, which can make the crystal grains fine by rapid cooling solidification effect, and improve the mechanial properties. We applied this method to try the direct wire making of hard and brittle, wear resistant Co-base alloys and the improvement of the mechanical strength. According to the characteristics of the production method, (1) the apparatus for vertical type spinning in rotating liquid for 0.1-0.3mm diameter and (2) the apparatus for horizontal type spinning in rotating liquidfor 0.3-0.5mm diameter were used. The kind of coolant is a very important factor, and in the case of this alloy, it was found that sodium carbonate aqueous solution was particularly effective. The wires obtained by rapid cooling solidification were heattreated (at 1273-1373K for 1h), and the stabilization of the metastable phase and the refining of the crystalline structure were carried out, in this way, the wires having the aimed-at wear resistance and mechanical strength were obtained.
The method of Electron Beam Floating Zone Melting (EBFZM) is well known as an effective treatment in refining of metals that has high melting point and reactive properties at high temperature.1, 2, 3 However, the sintered tungsten rod contains a great deal of gases.4 Thus, degassing is very important process for purification. In this present work, we refined tungsten rods by method of EBFZM, and estimated a purity of tungsten rods by measurement of Residual Resistivity Ratio (RRR)5, 6 and micro Vicker's hardness.7 As a result, it was confirmed as follows. 1. Annealing was very effective treatment in degassing of tungsten rods. 2. EB Gun's fast travel brought about a difference in refining conditions between rod's inside and one's surface, resulting in the formation of gaseous pools in rod's inside.
In the technique of producing functional gradient materials, made with different specific layers, a lot of intense investigations were done until now, especially in layers contactiong a surface and the control of interfaces. In our work, we tried to make FGM with a conventional method. The procedure is as follows: (1) fabrication of a porous bulk with a density gradient. (2) filling this bulk with a specific material. In the first step, we try to figure out the possibility of producing such a density gradient porous bulk.