In this paper, volume changes of rocks under uniaxial compression were studies experimentally for three different types of rocks such as sandstone, tuff and mable. The stiff loading system by means of stiffening bar method were employed and the volume changes were directly measured by using an improved Bridgman's dilatometer so that it was possible to obtain stress-volumetric strain curves in pre-and post-failure regions of rock samples.
The main results in this study are summerized as follows;
(1) The three characteristic curves depending on rock types were found in this study. They are shown in Fig. 10.
(2) In order to characterize the dilatant properties of rock samples quantitatively, two factors, rev andσ_cr/σ_maxwere selected. The former is the volumetric strain at the dilatancy initiation, the latter is the stress ratio between the stress at the critical strain and the maximum stress at failure. These values on rock samples are summerized in table 1.
(3) The measurements of volume changes were also performed on dry and wet samples. For sandstone both the stress levels to initiate dilatancy and the failure strength were fairly lowered in wet samples compared with those in dry samples, but for marble, the difference between the two states was scarcely observed. In tuff, dilatancy hardening was not occured both in wet and dry samples, however, failure strength was reduced in wet state.

抄録全体を表示

The phenomenon of frictional drag reduction with dilute polymer solutions in turbulent flow is well known as the Toms'effect.
Carrier fluid and polymer additives used in this test are fresh water, artificial sea water, polyethyleneoxide (PEO, 18N) and polyacrylamide (SEPARAN, AP30).
The relationship between the drag-reducing effect of solutions and the amount of the polymer additives in the carrier fluid is semi-theoretically analyzed, and in case of pumping the solution with a volute pump the mechanical degradation of solution is tested.
The experimental results are as follows.
(1) Pressure drop in turbulent pipe flow of fresh water can be reduced by about 78% when a small amount (20-100ppm) of PEO or SEPARAN is dissolved in the water.
(2) The correlations on the maximum drag reduction in turbulent pipe flow of dilute polymer solutions are formulized as follows:
1/√λ=8.5logR_e√λ-16.6 (PEO-fresh water system) 1/√λ= 12.4 logR_epλ^1-n/2-22.1 (SEPARAN-fresh water system) whereλ=resistance coefficient of pipe flow, R_e=usual Reynolds number, R_ep=generalized Reynolds number and n = flow behavior index.
(3) Each of all solutions of PEO-fresh water, of PEO-artificial sea water, and of SEPARAN-fresh water show high drag reduction. The SEPARAN is less stable in artificial sea water and shows only a little drag reduction, but stabler than PEO in fresh water against mechanical degradation.

抄録全体を表示

In related to the removal of Zn component in pyrite sinder, phase identification, grain size distribution and magnetic characteristics are investigated on the sintered materials from ZnO-Fe₂O₃mixture (1≥ZnO/Fe₂O₃≥0). Further, the feasibility to remove the Zn component as Fe-Zn ferrite from hematiteis examined by means of magnetic separation.
As a result, it was found that, under the suitable condition of sintering, minor Zncomponent can be segregated as ferrimagnetic Fe-Zn ferrite from hematite and sintering temperature is responsible for the grain size and chemical composition ofsegregated Fe-Zn ferrite.
In wet magnetic separation experiments of the sintered materials, the effective removal of the Fe-Zn ferrite could not be observed in spite of comminution enough to liberate hematite which is abundant component.The causes of the failure of this magnetic separation are traced on the artificial mixture of Fe-Zn ferrite and hematite. As a result, it is supposed that the mechanochemical reaction is occured in the course of comminution and it interferes the separation of Fe-Zn ferrite and hematite.

抄録全体を表示

The several experiments were made on the oxidation of CaCl₂mixed with SiO₂which is considered to be one of the basic reaction. The pellets of CaCl₂mixed with various amount of SiO₂were oxidized using the air or water vapor in the temperature range of 650°C-1, 100°C, and the rate and mechanism of reaction were studied by the continuous analysis of Cl₂or HCl gas produced during the experimental run.
We found that the oxidizing reaction begin at 550°C in the presence of water vaporand 680°C in air, and the rate of reaction was controlled by the chemical reaction. However, the rate process was affected by the amount of mixed CaCl₂at the temperature above m. p.of CaCl₂, and the rate of reaction was controlled by diffusion in the presence of large amount of CaCl₂.
The activation energy of reaction was about 12.9kcal in air and about 8.8kcal in water vapor for liquid CaCl₂ (about 19.5kcal for solid state). The oxidizing reaction was accelerated about 5 times in the presence of water vapor than the air under the same condition.
The rate was found to be directly proportional to the oxygen and water vapor pressure over the chemically controlled to the 3/2nd power of the gas pressure over the diffusion controlled. Throughout these studies, the compound of CaO·SiO₂was formed, and CaCl₂was discussed to act as the mineralizer for the formation of compound.

抄録全体を表示

The laboratory scale results of a process for direct smelting of copper sulfide-copper oxide ores under inert atmosphere are discussed in terms of reaction kinetics. The theoretical and experimental analysis of the process revealed that copper metal can be produced from sulfide and oxide ore concentrates continuously via several competitive and consecutive second-order reactions.
The experimental reactant mixture was comprised of Cu₂S-FeS-Cu₂O-SiO₂. The smelting process proceeds without injection of air into the system. The role of oxygen associated with cuprous oxide is similar to that of the oxygen in conventional copper converting.

抄録全体を表示