This paper describes a measurement system using with ultrasonic transducers to monitor airflow velocity in underground airways.
A flow velocity anemometer, which is able to monitor airflow rate of underground airways for a long term, is useful for ventilation managements and design.
When transport vehicles or locomotives are runing through airways, an usual point measurement anemometer, such as propeller type or thermal type one, have to be set near inside walls of airways. Further more, if average velocity is estimated based on a point measured value, presumption error becomes large because flow velocity profile reduces near walls.
The anemometer using with two 40kHz ultrasonic transducers set near wall of underground airways, hereinafter called an ultrasonic anemometer, has been developed. The anemometer measures the diffrence in travel time between two ultrasonic pulse-waves along and against the airflow. One transducer is located upstream of the other and transmittings of two waves are synchronized. The travel times of the ultrasonic waves in the upstream and downstream directions are measured over the same path as illustrated in Fig. 1. The diffrence in travel time is proportional to the airflow velocity. Analogue output and recording system using a simple composition circuit (Fig. 2) was used. And a digital counter circuit to measure the time differences (Fig. 3) was utilized to calibrate its analogue output as against airflow velocity.
Some experiments with ultrasonic anemometer related to airflow velocity were executed compared with a thermal anemometer at a loboratory. From the results, it is presumed that its measurement error is within 3% and its resolution is minimum 0.03m/s.
The ultrasonic anemometer has been investigated and examined at two metal mines from 1991.The anemometer doesn't become an obstacle for passing vehicles going through its setting area. The measurement error to estimate average velocity is relatively small and can detect flow direction.
When vehicles or workers pass though the measurement point, sudden increase or decrease of output voltage occurs. Using with these output characteristics, a method is presented to recognize passings of vehicle. The ultrasonic transducer did overcome disturbances of dusts by self-cleaning of its vibrating surface. In case of the examination in dusty airflow of the Fukasawa mine, it has been operated for five months without a maintenance.

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It is to be noted that velocity profile is an important parameter in regarding frictional phenomena between solid particles and pipe wall, critical deposit velocity, and sorting mechanism near the bed in settling slurry flows in a horizontal pipe. We propose in this paper two analytical models which could be used for the calculation of the velocity profiles in practical pipeline design: an acceleration model and a nearly steady flow model. Based on the hypothesis that steady slurry flow would be produced through the encounter of water flow to no moving suspended solid particles with a fixed distribution of concentration in water, the models have been derived by the analysis of the change in momentums both of solid particles and water with time, and by the analysis of equilibrium conditions of forces acting a particle in a nearly steady flow. Predictions from the models are compared with experimental results obtained from published papers, and are verified to be reliable.

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Extraction of nickel ions from concentrated solutions with Versatic Acid 10 (VA10) was studied by considering a chemical equilibrium state attained between the aqueous and organic phases. In the extraction experiments, amounts of nickel extracted from the aqueous to organic phases sensitively depend on pH values in the aqueous phase and increase with an increase in pH values. In the case of highly concentrated VA10, the concentration of nickel in the organic phase linearly increases with pH values and at higher pH values, an equilibrium state is achieved where almost all nickel ions are extracted from aqueous to organic phases. When VA10 concentration is not so high, on the other hand, another equilibrium state is achieved where concentrations of nickel In both organic and aqueous phases become nearly constant as pH values become higher. According to these experimental results, a thermodynamical analysis was made to assess chemical compositions of extracted species of nickel from the concentrated solutions. It was shown that extracted species of nickel from the concentrated solutions would be the same form of dimer as was determined by Shibata et al. in the case of diluted solutions. An apparant equilibrium constant estimated in the analysis, however, significantly increases as the initial concentrations of nickel in aqueous solutions become higher.

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The particle velocity is one of the most important factors on the dynamic characteristics of solid-liquid two-phase flows, however the investigations on the velocity in a pipe under swaying motion are not found. In this paper, the streamwise particle velocity in a swaying and horizontal pipe was theoretically and experimentally discussed. The velocity was measured by means of a digital image processing and the main results are as follows:
1. The modified Froude number for the particle in the swaying pipe is defined by the equation (23).
2. An auto-correlation analysis of the streamwise velocity of particles has shown that the velocity fluctuation has the period same as that of pipe swaying, T_p, and the period is independent of a mean velocity of solid-liquid mixture and at amplitude of pipe swaying.
3. A cross-correlation Analysis between the streamwise velocity of particles' and the swaying velocity of the pipe has shown that the streamwise velocity fluctuation has a phase gap of about +0.4T_p to that of the pipe swaying.
4. The empirical equations concerning to the average values of the streamwise particles' velocity and the amplitudes of its fluctuation were obtained as equations (22), (24), (25), (26), (28) and (29).

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Estimating the cobalt behavior in speiss and smelting processes of copper and nickel, the arsenic activities in Co-As binary alloys were investigated by an isopiestic method in the composition range between 25 and 50 mol%As at 1, 273 and 1, 423 K. The arsenic activity exhibits extremely negative deviation from the Raoult's law, which suggests formation of a stable arsenic alloy, speiss, as well as iron and nickel systems.
The two phase region of the primary solid solution of cobalt and liquid in the Co-As binary system was also determine by a quenching method combined with the EPMA technique in the temperature range between 1, 273 and 1, 473 K. The region extends from 4.9 to 21.5 mol%As at 1, 423 K, and the liquidus composition shifts about 1.5 mol% to the arsenic side from that in the Co-As phase diagram compiled by Massalski et al.
Activity of cobalt calculated from the arsenic activity by using the determined two phase region in the present study shows negative deviation from ideality in the homogeneous region, while positive deviation is observed in the composition range of the two phases.
The standard free energy of formation for Co₂As (l) was established from the activities of the elements, and the result is as follows: 2Co (s) +As (1) =Co₂As (1)ΔG°/J=11, 200-47T (1, 273-1, 423K).

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Direct application of the usual electrowinning process for recycled zinc resources is limited because of the contamination by chloride anion, which promotes dissolution of the lead anode and causes an increase in lead content to cathode zinc. A fundamental study has been made of a newly proposed process for the elimination of small amount of chloride anion from acidic sulfate solutions. The process is composed of anodic oxidation followed by the purge of evolved chlorine. At current densities of 120A/m² and 300A/m², the rate of the decrease in anion concentration was proportional to the first-order of the concentration. The rate constant determined with a flask cell (1.0×10^-3m³) equipped with a metal anode (4.0×10^-3 m²) was 1.3×10^-4 S^-1. At 20A/m² the process proceeded independent of the anion concentration at the early stage, and after 4h the rate of the decrease was described by the relation given at 120A/m² and 300A/m². Current-potential curves determined with a rotating disk electrode showed that the anodic oxidation of chloride ion is controlled by diffusion and that the application of the anodic current over the limiting current density has no effect on increasing the rate constant. The electrolysis conducted in a recirculation cell (1.7×10^-3 m³) with a carbon fiber cloth anode (1.5×10^-2 m², 3 sheets in cascade) yielded a rate constant of 1.6×10^-3 S^-1. Such electrolysis has proved to be a rapid method for removing chloride anion from sulfate solutions.

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The knowledge for the failure process of rock slope is of fundamental importance to asses the slope stability.
In this paper, a numerical procedure to analyze the failure process of rock slope by the Displacement Discontinuity Method (DDM) is proposed, then the failure process and the failure mode of homogeneous rock slope are discussed.
In the numerical analysis, the rock slope is modeled as the elastic material and the process of crack initiation and crack propagation is analysed by DDM. The cohesion of the crack surfaces is treated to be dependent on the displacement discontinuity of the crack. It is made clear that the failure process and the failure mode of rock slope is closely connected with the strength characteristics of the crack surfaces as well as the slope angle by demonstrating the numerical results. It is shown that the slope failure occurs by connecting the conjugated shear cracks, in the case that the critical value of crack shear displacement (CSD) is relatively small. On the other hand, the tensile fracture occurs at the crack tip of the shear crack plays an important role in progressing the slope failure, in the case that the critical value of CSD is relatively large.
The critical value of stability factor obtained by the present analysis agrees with the experimental value reported by OKAMURA et al., but dose not with that obtained by the conventional limiting equilibrium analysis.
It is pointed out that the influence of the slope angle on the slope stability is less than that predicted by the conventional limiting equilibrium analysis, although the critical value of stability factor increases with decreasing the slope angle.

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The Permeability of the Shirahama sandstone was measured as a function of three principal stresses. A transient pulse method was used to measure the permeability. Permeability was determined from measurements of the decay of a small step change of pore pressure imposed at maximum stress direction. The measurements were made with increasing intermediate stress as well as with increasing maximum stress under constant minimum stress of 5 MPa, 10 MPa, 15 MPa, 20 MPa. Permeability changes due to maximum stress were dominant than those due to intermediate stress. Blue dyed epoxy impregnated thin sections of intact and stressed Shirahama sandstone were prepared to clarify pore structure change. Using an image processing technique, porosity, orientation and aspect ratio of pores can be estimated. Permeability decrease due to increase of three principal stresses can be interpreted in terms of the closure of preexisting pores with low aspect ratio and long perimeter.

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Today, the non ferrous metals such as copper, brass, lead and zinc in car scrap are not systematically recovered, although the iron and the aluminum contained in car scrap are recovered. Therefore, for the recycling of resources and the preservation of natural environment, we started to make a study of recovery system of the non ferrous metals from the car scrap. In this paper, we conducted the separation experiments by using the ECHO Metal Jig (Type-SP) with jig box having the dimension of 250mm in width, 250mm in length and 300 mm in height, which is particularly made for an experimental purpose. And -10mm shredder dust abandoned in the scrap factory is treated with this jig and separated into three products (non metal dust, middling and non ferrous metal concentrate). The effect of gate height, feed speed and pulsation time for middling separation has been investigated.
The results obtained through the experiments are summarized as follows;
(1) The gate height at middling separation; Most effective factor is the gate height at middling separation.
When the gate height is higher, the weight and the recovery of concentrate increase and the grade of that decreases, and vice versa.
(2) The feed speed; Throughout this test, 0.54kg/s of feed speed gives maximum concentrate recovery and the best separation performance.
(3) The Pulsation time for middling separation; The pulsation time for middling separation has no effect on the grade, recovery of the concentrate and the separation performance.
(4) The best operating condition of this jig is as follows; 200mm of gate height at middling separation, 20s of pulsation time for middling separation and 0.54kg/s of feed speed.
(5) This jig is very effective for -10mm shredder dust, since over 90% of valuable metals having over 7.0 of specific gravity is recoverable with this jig separator.

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Removal of iron minerals such as goethite and hematite from bauxite ore from Indonesia was investigated by using a wet type high gradient magnetic separator (HGMS). The bauxite sample was subjected to grinding by a tumbling ball mill for liberation of mineral components prior to the separation test. Concentration of Al₂O₃ in non-magnetics separated by HGMS increased with a decrease in particle size of feed sample. Al₂O₃ concentration was also increased by adjusting pH value of feed slurry at around 11.5 or by adding a dispersing agent to the slurry. The typical concentration of Al₂O₃ in non-magnetics obtained in the present study was about 56 mass% when using the bauxite sample containing about 51 mass% Al₂O₃ with fractional yield of approximately 80 mass%. Concentration of Fe2O3 in the non-magnetics was decreased to around 8 mass% from the original value about 14 mass%. On the basis of this result, the amount of bauxite residue as waste (so called red mud) discharged from the Bayer process will be reduced significantly.

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Plasma arc melting apparatus having very low leak rate was designed and installed for melting and casting of reactive metal based intermetallic compound such as TiAI or Nb 3A1.
It is equipped with one plasma torch of maximum output of 20 kW in continual operation and can be operated under adjusted pressure ranged from 6, 000 to 101, 325Pa using inert gas such as Ar or Ar-He mixture.
To verify the leak rate of this apparatus, titanium is melted and the contents of oxygen and nitrogen in titanium was monitored.
Approximate 80g of titanium was melted on the copper crucible under 70V of plasma arc voltage, 130A of arc current and 60 kPa of high purity argon gas.
The increasing rate of nitrogen in titanium determined by chemical analysis was 0.05ppm/s and agreed with that calculated from the leak rate measured.

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