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121.
Technology of constructing blast-filled dams and geotechnical properties of soils of such structures
G. I. Pokrovskii N. P. Lushnov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1992,26(7):395-400
1. | The use of collapse blasting for constructing rock dams substantially increases the technical and economic indices of the blasting technology of constructing earth dams. |
2. | The selection of the technology of constructing blast-filled dams is determined mainly by the engineering-geological conditions at the construction site. At present it cannot be confirmed whether the use of loosening blasting promotes an increase of the geological properties of soils forming the body of blast-filled dams. |
3. | Further investigations of the process of movement of blasted rock down a mountain slope with determination of the volume of moving rock, time, andvelocity (acceleration) for a known degree of slope roughness are required for a more complete comparison of the effectiveness of the two existing technologies of constructing dams by directional blasting. Such investigations also enable determining the possibility of using the Amontons-Coulomb law of friction for describing the movement of large earth masses. |
122.
V. N. Zhivoderov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1992,26(6):337-345
1. | An analysis of the results of a unique on-site experiment at the Sayano-Shushenskoe dam on regrouting the sites of column and radial joints under practically equal conditions was carried out for the first time in our country. Information about analogous works could not be found in the foreign literature. |
2. | The works performed indicate the effectiveness and high performance of the multiple grout outlets designed by Gidrospetsstroi. |
3. | Having equal conditions of grouting sites of column and section joints under conditions of the upper pool head (H=60 m), we can say the following: |
123.
A. F. Dmitriev A. I. Tyshenko N. N. Khlapuk 《Power Technology and Engineering (formerly Hydrotechnical Construction)》1992,26(5):306-310
1. | It is necessary to correlate the value of the noneroding velocity with the time of flood passage. If canals are planned in regions where comparatively brief summer floods are dominant, the value of the noneroding velocity should be taken equal to 3 m/sec since by the start of the flood the grass cover will have time to develop and reach maximum strength. If the canals are to be constructed in regions where spring floods are dominant, for example, in the northwestern regions of the country, then the noneroding velocity should be taken equal to 1.5 m/sec, since by the start of the flood the grass carpet does not have time to develop and become stronger. |
2. | In the absence of a constant runoff in the canal, for example, drainage canals, it is necessary to revet the bottom and side slopes with grass carpets. |
3. | In the presence of a constant moistening is made from traditional materials, in the zone of alternate moistening and above it, it is necessary to revet the slopes within reinforced grass carpet. |
4. | In a hydraulic calculation of canals with revetment of the bottom and side slopes with grass carpet, it is necessary to determine the roughness coefficient from the graph of n=f(VR, i). In a hydraulic calculation of wide overgrown channels and in calculation of the movement of the flow over floodplain stretches of rivers free from shrubs and trees, it is necessary to determine the roughness coefficient from the graph of n=f(Vh, i). |
5. | Calculation of canals with nonuniform roughness (rigid revetment and revetment by grass carpets) must be carried out on the basis of relations of uniform flow by means of a generalized roughness coefficient. |
124.
Tompkins NC 《HRMagazine : on human resource management》1992,37(6):66-7, 69-70, 72
Marrying workers' compensation and health insurance plans to reduce administrative workloads and get a firm grip on expenses. Can it work? 相似文献
125.
Operational Research and the environment 总被引:1,自引:1,他引:0
The discipline of Operational Research (OR) is primarily concerned with improving the effectiveness and efficiency of decision processes. These processes take place everywhere in society: industry, banking, agriculture, government, politics. Frequent use of mathematical optimization models is typical of OR. Since the early '80s these models are increasingly packaged in a user-friendly way, as Decision Support Systems. In the following we will illustrate how OR can be used to describe and solve a number of environmental problems. 相似文献
126.
In this paper, we discuss the properties of preliminary test estimators (PTE) of the parameters of simple linear model with
measurement error (ME model) when the slope of the linear model is suspected to be zero. Expressions of the bias, MSE and
efficiencies are obtained under conditional as well as unconditional situations with known reliability coefficient. Conditional
model results are compared to the standard model without measurement error. We also provide the unconditional model analysis
in finite samples. Asymptotic theory under local alternatives is developed when the variance of measurement error or the ratio
of the variance of the model error relative to the variance of the measurement error is known. Asymptotic expressions of bias
and MSE of the estimators along with their efficiencies are obtained. In every case, it is shown that the measurement error
tend to increase the variability of the estimators compared to the estimators without measurement error. Graphs and tables
are provided to see these results and to determine optimum level of significance for minimum guaranteed efficiency.
Received October 2001
RID="*"
ID="*" A. K. Md. E. Saleh is a Distinguished Research Professor and H. M. Kim is a Ph.D. candidate in the School of Mathematics
and Statistics, Carleton University, Ottawa.
Acknowledgment. The authors gratefully acknowledge the constructive suggestion of the referees to improve the paper. The research is supported
by NSERC grant A3088. 相似文献
127.
128.
In this paper, progressive stress accelerated life tests are considered when the lifetime of a product under use condition
follows a finite mixture of distributions. The experiment is performed when each of the components in the mixture follows
a general class of distributions which includes, among others, the Weibull, compound Weibull, power function, Gompertz and
compound Gompertz distributions. It is assumed that the scale parameter of each component satisfies the inverse power low,
the progressive stress is directly proportional to time and the cumulative exposure model for the effect of changing stress
holds. Based on type-I censoring, the maximum likelihood estimates (MLEs) of the parameters under consideration are obtained.
A special attention is paid to a mixture of two Rayleigh components. Simulation results are carried out to study the precision
of the MLEs and to obtain confidence intervals for the parameters involved. 相似文献
129.
In this paper characterizations of negative multinomial distributions based on conditional distributions have been studied. 相似文献
130.
We characterize the equilibrium of the all-pay auction with general convex cost of effort and sequential effort choices. We
consider a set of n players who are arbitrarily partitioned into a group of players who choose their efforts ‘early’ and a group of players who
choose ‘late’. Only the player with the lowest cost of effort has a positive payoff in any equilibrium. This payoff depends
on his own timing vis-a-vis the timing of others. We also show that the choice of timing can be endogenized, in which case
the strongest player typically chooses ‘late’, whereas all other players are indifferent with respect to their choice of timing.
In the most prominent equilibrium the player with the lowest cost of effort wins the auction at zero aggregate cost.
We thank Dan Kovenock and Luis C. Corchón for discussion and helpful comments. The usual caveat applies. Wolfgang Leininger
likes to express his gratitude to Wissenschaftszentrum Berlin (WZB) for its generous hospitality and financial support. 相似文献