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## Estimation of rock mass modulus

### International Journal of Mining and Geological Engineering (1989-06-01) 7: 175-181 , June 01, 1989

## A review of storm-surge research in China

### Natural Hazards (1989-03-01) 2: 17-29 , March 01, 1989

In this paper are briefly introduced: (1) the general situations of storm hazards caused by different weather types; (2) the acquisition of data needed in storm-surge forecasting; (3) the current forecasting techniques of storm surges; (4) the calculations of storm surge with different return periods for coastal engineering and the exploitation of the ocean; and (5) the basic theoretical study of storm surges.

## Classical confidence intervals and Bayesian probability estimates for ends of local taxon ranges

### Mathematical Geology (1989-05-01) 21: 411-427 , May 01, 1989

The observed local range of a fossil taxon in a stratigraphic section is almost certainly a truncated version of the true local range. True endpoints are parameters that may be estimated using only the assumption that fossil finds are distributed randomly between them. If thickness is rescaled so that true endpoints lie at 0 and 1, the joint distribution of gap lengths between fossil finds is given by the Dirichlet distribution. Observed ends of the range are maximum likelihood estimators of true endpoints, but they are biased seriously. Extension of the observed range at each end by a distance equal to the average gap length yields unbiased point estimators. Classical statistics can generate confidence intervals for ends of the taxon range; but with Bayesian inference, the probability that true endpoints lie in a certain region can be stated. For a 95% confidence level (classical) or a 95% probability (Bayesian), the range extensions exceed the observed range if the range is established on less than six finds; if only two finds are used, such range extensions are an order of magnitude longer than the observed range. Evidently the standard biostratigraphic practice that identifies zonal boundaries as horizons rather than confidence intervals may not be justified at the resolution of typical fossiliferous sections.

## A hydraulic brake of a striker and its force characteristics

### Soviet Mining (1989-07-01) 25: 365-369 , July 01, 1989

### Conclusions

1.

The form of the force characteristics of a hydraulic braking device is independent of the initial energy of the body being braked, which makes it possible to vary the striker energy not fearing deterioration of the braking device performance.

2.A braking device with a constant throttle cross section area is suboptimal in terms of loads experienced by its components.

3.A braking device with a rectangular brake characteristic (a constant-resistance brake) exhibits an essentially unstable form of the braking chracteristic. There is a danger not only in the wear and tear of the shaped element of the brake but also in leaks through constant cross section openings. In both situations there is a pressure overshoot at the end of the braking process, which is equivalent to a rigid collision of brake elements.

4.A brake with a linear relationship betwen the throttle cross section and the brake path exhibits the most stable brake characteristic of all the devices studied. The level of nonuniformity of this characteristic is well acceptable for practical purposes The form of the characteristic changes slightly as the shaped element of the brake is worn out. In addition, it is not too sensitive to a constant leak. Braking devices of this kind can be recommended for high-energy impact machines.

## Climatic study on the summer tropical easterly jet at 200 hPa

### Advances in Atmospheric Sciences (1989-06-01) 6: 215-226 , June 01, 1989

The low latitude easterlies at 200 hPa in summer (May–October) is analysed climatically during the 13-year period from 1968 to 1980, with a special emphasis on the relationships between the anomalous tropical easterly jet Stream over South Asia and the low latitude atmospheric circulation, and also the summer monsoon precipitation in India. The compositing analysis shows that the tropical easterly jet stream over South Asia has five anomalous patterns at 200 hPa i.e. the western pattern, middle pattern, eastern pattern, two-branch pattern and multi-core pattern. Evidence has shown that the precipitaion in India anomalously increased during the anomalous period of the western pattern and the middle pattern, but reverse case is true in the eastern pattern. Some different anomalies of the precipitation in different area of India were found during the other two anomalous pattern.

## Transformation of enstatite — diopside — jadeite pyroxenes to garnet

### Contributions to Mineralogy and Petrology (1989-08-01) 102: 389-405 , August 01, 1989

The high-pressure stability of enstatite(En)-diopside(Di)-jadeite(Jd) pyroxenes has been investigated experimentally with a split-sphere anvil apparatus (USSA-2000). On the enstatite-pyrope join, the compositions of garnet coexisting with enstatite were determined at 100–165 kbar and 1450–1850° C. The results indicate complete solubility between enstatite and pyrope. In the system CaO-MgO-Al_{2}O_{3}-SiO_{2} (CMAS), the compositions of coexisting pyroxenes and garnet were determined at 100–165 kbar and 1250–1750° C. At 157 kbar, 1650° C, garnet with the composition En_{79}Di_{21} (mol%) forms on the En-Di join. In the system Na_{2}O-MgO-Al_{2}O_{3}-SiO_{2} (NMAS), the compositions of coexisting pyroxenes and garnet were determined at 60–160 kbar and 1200–1850° C. On the En-Jd join, the first garnet has the composition En_{48}Jd_{52} at 135 kbar, 1650° C, and En_{53}Jd_{47} at 140 kbar, 1500° C. On the Di-Jd join, the first garnet with the composition Di_{63}Jd_{37} forms around 170 kbar, 1650° C. In the En-Di-Jd system, the first appearance of garnet with the composition En_{42}Di_{9}Jd_{49} is estimated at 133 kbar, 1650° C. The new pyroxene with the composition NaMg_{0.5}Si_{2.5}O_{6} (NaPx) transforms to garnet at 154 kbar, 1650° C. The experimental results indicate that the transformation of a twopyroxene assemblage to garnet and residual pyroxene in the En-Di-Jd system could occur at pressures consistent with the 400 km seismic discontinuity and in a pressure interval of 0–3 kbar.

## Numerical model of contaminant transport through conduit-porous matrix system

### Mathematical Geology (1989-10-01) 21: 861-890 , October 01, 1989

A mathematical model for determining solute concentrations at a point within a cylindrically symmetrical conduit-porous matrix system is described. Both convection and diffusion are considered within the conduit subsystem, whereas only diffusion is considered within the porous matrix subsystem. The two subsystems are coupled through continuity conditions imposed at their interface boundary. The transport equations are solved utilizing an alternating-direction implicit-method technique. The solute concentration profiles resulting from this model are then sketched and discussed.

## Numerical simulation of three-dimensional saturated flow in randomly heterogeneous porous media

### Transport in Porous Media (1989-12-01) 4: 549-565 , December 01, 1989

This paper presents a numerical method for simulating flow fields in a stochastic porous medium that satisfies locally the Darcy equation, and has each of its hydraulic parameters represented as one realization of a three-dimensional random field. These are generated by using the Turning Bands method. Our ultimate objective is to obtain statistically meaningful solutions in order to check and extend a series of approximate analytical results previously obtained by a spectral perturbation method (L. W. Gelhar and co-workers). We investigate the computational aspects of the problem in relation with stochastic concepts. The difficulty of the numerical problem arises from the random nature of the hydraulic conductivities, which implies that a very large discretized algebraic system must be solved. Indeed, a preliminary evaluation with the aid of scale analysis suggests that, in order to solve meaningful flow problems, the total number of nodes must be of the order of 10^{6}. This is due to the requirement that Δ*x*_{i} ≪ *gl*_{i} ≪ *L*_{i}, where Δ*x*_{i} is the mesh size, *λ*_{i} is a typical correlation scale of the inputs, and *L*_{i} is the size of the flow domain (*i* = 1, 2, 3). The optimum strategy for the solution of such a problem is discussed in relation with supercomputer capabilities. Briefly, the proposed discretization method is the seven-point finite differences scheme, and the proposed solution method is iterative, based on prior approximate factorization of the large coefficient matrix. Preliminary results obtained with grids on the order of one hundred thousand nodes are discussed for the case of steady saturated flow with highly variable, random conductivities.

## The impact of base-level analyses on stratospheric circulation statistics for the Southern Hemisphere

### pure and applied geophysics (1989-06-01) 130: 181-194 , June 01, 1989

The impact of different base-level analyses on derived stratospheric circulation statistics for the Southern Hemisphere has been assessed. Three different sets of daily operational analyses of geopotential height at 100 hPa for September, 1981 have been used as the base-level analyses, combined with a single set of daily thickness analyses for the stratosphere. The circulation statistics considered include mean fields, transient eddy statistics, Eliassen-Palm flux diagnostics and vorticity fields.

In general, the different base-level analyses do not change the qualitative description of the circulation statistics but they lead to marked quantitative differences, particularly at high latitudes. The statistics which are most sensitive to the different base-level analyses are those which emphasise the shortest space scales through multiple differentiation of the height field and the shortest time scales, such as daily Eliassen-Palm flux diagrams or the daily vorticity fields.