Tail Flow Research Articles

天草陶石の脱長石浮選に関する研究 （第２報） 天草陶石の連続式浮選試験とその速度論的考察

Following in the first report which elucidated that feldspar (albite) was effectively removed from low grade Amakusa pottery clay by two-stage flotation in laboratory batch-test, continuous flotation has been applied to the process. The results are as follows:1) The semi-batch tests, which were carried out before continuous flotation tests, indicated that each mineral was devided into two groups having the slow and fast flotation rates.2) In the rougher stage of continuous clay flotation, concentrations of collector were higher than the values expected from the semi-batch tests and tailing flow rate of pulp remarkably decreased owing to discharge of froth. As a result, the residual mass ratios showed lower than the simulated value on the basis of the results of semi-batch tests.3) In feldspar flotation, the residual mass ratios agreed well with the simulated ones because tailing flow rate of pulp did not decrease so much and the concentrations of collector were almost consistent with the ones in the semi-batch test.4) The refractoriness of the products obtained by the continuous flotation was improved. It was verified that the continuous flotation process for the removal of feldspar from the low grade Amakusa pottery stone is technically feasible.

Rheology and flow of phosphate slurries (mine tailings) in pipes

AbstractAn experimental study of the flow of phosphate mine tailings was carried out in order to characterize these suspensions of fine particles for pipeline transport. Rheological measurements with a rotating cylinder viscometer indicate a viscoplastic behaviour which can be represented by a Herschell‐Bulkley or by a Casson model. The variation of the parameters of these models with solids concentration reveals a change in the behaviour at a concentration of 10 to 15%. The pressure drops were measured during flow in capillary tubes, in both laminar and turbulent regimes. The variation of the pressure drop coefficient (Fanning friction factor) as a function of the generalized Reynolds number confirms the validity of the employed rheological models. The results are in good agreement with measurements made in pipes of industrial size. The velocity profiles measured with a novel ultrasonic velocimeter demonstrate the influence of the rheological behaviour on the yield and wall stresses.

Analyses of Flow Failures of Mine Tailings Dams

A characteristic common to most tailings dam failures is that the mine tailings tend to liquefy and flow over substantial distances, with potential for extensive damage to property and life. In order to be able to assess the potential for damage in case of such failure, it is necessary to be able to predict the characteristics of the flow and the possible extent of flood movement. This paper presents analytical procedures for making such evaluations. The behavior of tailings materials during flow is represented by a Bingham plastic rheological model in these analysis procedures. It is apparent from the analyses that the flow of phosphate tailings would be expected to be turbulent but flows for other types of tailings would be expected to be laminar. The procedures described are applicable for flow of tailings on horizontal and sloping planes and in prismatic valleys. The analyses can be performed using dimensionless charts in the case of flow on planes, and a computer program in the case of flow in prisma...

Antipyrine and Acetaminophen Kinetics in the Rat: Comparison of Data Based on Blood Samples from the Cut Tail and a Cannulated Femoral Artery

Antipyrine and acetaminophen kinetics were determined from concentration data obtained by simultaneous blood sampling from the cut end of the tail and a cannulated femoral artery in the rat. Significant differences in concentrations and kinetics for both drugs were found by comparison of the two sampling sites. The hypothesis that the differences were due to a low tail blood flow was tested. The tail blood flow was measured with a microsphere technique, and tail antipyrine concentrations were calculated from the relationship between arterial antipyrine concentration, tail flow, and time for comparison with the observed antipyrine concentrations. Mean blood flow of the rat tail was 0.02ml/min/ml tail tissue at 22°, which was 8.8 and 0.9% of the liver and kidney flow, respectively. Tail flow increased more than twofold by elevation of the tail temperature to 37°. The calculated tail antipyrine concentration versus time curve showed a very close correspondence to the observed antipyrine tail concentration versus time curves. The results show that tail flow is a major determinant of antipyrine tail concentration in the rat. Kinetic data based on blood samples from the cut end of the tail, therefore, should be interpreted with caution.

Titan's ion exosphere observed from Voyager 1

Electron and ion measurements made by the Voyager 1 plasma science instrument revealed a plasma wake surrounding Titan in Saturn's rotating magnetosphere. This wake is characterized by a plasma that is more dense and cooler than the surrounding subsonic magnetospheric plasma. The density enhancement is produced by the deflection of magnetospheric plasma around Titan and the addition of exospheric ions picked up by the rotating magnetosphere. By using simple models for ion pickup in the ion exosphere outside Titan's magnetic tail and ion flow within the boundaries of the tail, the interaction between Saturn's rotating magnetosphere and Titan is shown to resemble the interaction between the solar wind and Venus. Outside the magnetic tail of Titan, pickup of H+ formed by ionization of the H exosphere is indicated when synthetic and observed ion spectra are matched. Close to the boundary of the tail, a reduction in plasma flow speed is found, providing evidence for mass loading by the addition of N2+/H2CN+ and N+ to the flowing plasma. The boundary of the tail is indicated by a sharp reduction in the flux of high‐energy electrons, which are removed by inelastic scattering with the atmosphere and centrifugal drift produced when the electrons traverse the magnetic field draped around Titan. Within the tail the plasma is structured as the result of spatial and/or temporal variations. The ion mass cannot be determined uniquely in the tail; however, one measurement suggests the presence of a heavy ion with a mass of order 28 amu: One candidate is H2CN+, suggested as the dominant topside ion of the ionosphere, which may flow from the ionosphere into the tail.

Effect of face immersion on body temperature and tail blood flow in the rat

1. 1. Changes in tail blood flow, rectal, colonic and tail temperature produced by simulated diving were measured in anaesthetised rats, and the temperature changes were compared with those produced by arresting tail flow with a tourniquet. 2. 2. “Diving” produced a rapid fall in tail blood flow from 30 to 40 ml/100 ml per min to zero within 15–30 sec. 3. 3. Tail temperature fell at the same rate whether tail flow was halted by “diving” or tourniquet. 4. 4. Rectal, and sometimes colonic, temperature fell during “diving”; both rose with tail tourniquet. 5. 5. Colonic temperature fell below pre-procedure level when tail temperature and flow recovered after “diving”. 6. 6. Metabolic depression induced by “diving” is suggested.