坝上水文站悬移质颗粒级配测验优化分析

为科学合理地在坝上水文断面开展悬移质颗粒级配测验,更好地收集相关水文资料,根据1956~2019年连续64年含沙量资料及1970~2019年连续50年粒径资料,分析了流域泥沙变化趋势,开展了受水利工程影响的坝上站悬移质颗粒级配测验方式优化分析工作,制定完善的测验优化方案,可保证在新水沙特性下水文资料收集的代表性和精度的同时减轻测验工作量。

青铜峡水文站悬移质含沙量测验优化分析

文章主要对青铜峡水文站1996~2015年连续20年实测悬移质含沙量资料进行了分析,论证该站悬移质含沙量测验优化的可行性,并制定完善的测验优化方案。

徐六泾站潮流量测验测次布置与垂线优化分析应用

徐六泾水文站是长江入海口的控制水文站,其潮流量测验和整编采用代表线法,即以声学多普勒流速仪连续定时测验代表线流速、流向,再以组合代表线流速与相应断面流量间关系推求全断面不同时刻潮流量过程资料。以前阶段断面上共布设有5条代表线,并按季度每年对组合代表线流速与相应断面流量间关系进行4次率定测验。近期随着长江航运业的快速发展,断面上过往船舶数量迅速增加,全盘走航式声学多普勒流速仪测验及代表垂线浮标测流系统安全隐患越来越大,且率定测验工作量巨大,费用昂贵。本文以《水文资料整编规范》为依据,采用误差分析理论,分析将有关测流代表线移至安全位置、减少代表线数及率定测验次数的可行性。结果表明,将2#、3#、4#浮标测流系统移至安全位置及减少二季度率定测验是可行的;采用三组合和四组合两种代表线法推流也基本满足水文测验规范的有关规定。

黄河水沙监测数据分析中的问题探讨

介绍了黄河下游孙口水文站概况和实施水沙监测的工作概况,分析研究了近年来水文站径流量与输沙量等水文特征.通过对该水文站全年实际监测流量与含水沙量的方法和过程的分析,从时间和空间上提出了测验的优化方案设想,明确了可减少垂线条数和取样点个数的优化方案,构想了利用断面平均水流速与其挟沙力的关系来计算含沙量的方法,用于减少系统误差,并初步探讨了调水调沙对河床冲刷演变的影响.

The response of collision speed caused by the large bus to new flexible barrier

In order to study the response of collision speed caused by the large bus to new flexible barrier,in this paper,with the large bus as the carrier,the full-scale impact tests between flexible barrier and vehicle with the impact velocities of 40 km/h and 60 km/h were carried out separately,following the procedures of the test preparation,test processing,data acquisition, etc,which were based on the test platform of the Large Structure Crash Testing Laboratory of Changsha University of Science and Technology. The important test results which contain the damage of vehicles and barrier,the moving locus of vehicle,the occupant risk index,the maximum dynamic deformation, etc,were obtained through the analysis under the different collision speeds. These provide the necessary reference basis for the further research on the structure topology optimization and improve the comprehensive constraint performance to the flexible barrier.

Experiment study of optimization on prediction index gases of coal spontaneous combustion

The coal of Anyuan Mine has the characteristic of easy spontaneous combustion. Conventional method is difficult to predict it. Coal samples from this mine were tested in laboratory. The data obtained from laboratory determination were initialized for the value which was defined as "K". The ratio of each index gas and value of "K", and the ratio of combination index gases and value of "K", were analyzed simultaneously. The research results show that for this coal mine, if there is carbon monoxide in the gas sample, the phenomenon of oxidation and temperature rising for coal exists in this mine; if there is C_2H_4 in the gas sample, the temperature of coal perhaps exceeds 130 °C. If the coal temperature is between 35 °C and 130 °C, prediction and forecast for coal spontaneous combustion depend on the value of Φ(CO)/K mainly; if the temperature of coal is between 130 °C and 300 °C, prediction and forecast for coal spontaneous combustion depend on the value of Φ(C_2H_6)/Φ(C_2H_2) and Φ(C_2H_6)/K. The research results provide experimental basis for the prediction of coal spontaneous combustion in Anyuan coal mine, and have better guidance on safe production of this coal mine.

Prediction of the Maximum Flow by the Model SASIS： Sensibility to the Empirical Parameters of the Shape of the Furrow

The model developed in this research presents effective mechanisms in simulations of a discharge strip understood between the minimum and the maximum allowable values, aiming to determine the relationship between discharge and water application efficiency, deep percolation and runoff rates, and consequently to optimize the performance of the furrow irrigation systems with continuous flow. The flow applied in each furrow must be adapted to the length, to the field slope and to the nature of the ground. The authors studied the maximum non erosive flow （Q,,,~）, in function of parameters obtained from the dimensions of the furrow, being Pl and/92, respectively, the linear and exponential parameters of the potential functions that described the relationship between the area of the cross section of flow （or wetted perimeter） and height of flow; in this way, the multiplicative effect of,01 on the area of the cross section of flow is linear, while ,02 is exponential. It verified a conjugated effect of,or and p20n the value of Q,,~. The results of this research point out for the importance of having an estimate of the parameters of the geometry of the cross section of flow （,01 and ,02） the most precise as possible, being known that the dimensions of this section can result in impracticable values of Qmax, outside of the acceptable strip in the literature, that is from 1.2 to 4.0 L.sl. This sensibility analysis was also of great benefit to create an interface in the software SASIS, capable to guide the user of this tool in the input of appropriate values for ,01 and P2 to the process of simulation of the irrigation for furrow with continuous flow and of the optimization of its performance.

Application of Genetic Algorithms to Optimize Neural Networks for Selected Tribological Tests

This paper presents a method of determining the friction coefficient in metal forming using multilayer artificial neural networks based on experimental data obtained from strip drawing test. The number of input variables of the artificial neural network has been optimized using genetic algorithm. This process is based on surface parameters of the sheet and dies, sheet material parameters and clamping force as input parameters to train the neural network. In addition to demonstrating the fact that regression statistics model using genetic selection and intelligent problem solver are better than models without preprocessing of input data, the sensitivity analysis of the input variables has been conducted. This avoids the time-consuming testing of neurons in finding the best network architecture. The obtained results from this study have also pointed out that genetic algorithm can successfully be applied to optimize the training set and the outputs agree with experimental results. This allows reduction or elimination of expensive experimental tests to determine friction coefficient value.

Optimal design and experimental measurement of the subharmonic characterizations of encapsulated microbubble

Based on a theoretical motion equation of encapsulated microbubbles within an ultrasound field, the subharmonic characterizations of microbubbles are optimally designed and analyzed by a computer aided design system. The effects of size, shell elasticity and acoustic pressure on subharmonic response of microbubbles are calculated theoretically to obtain the optimal parameters for nondestructive subharmonic imaging. In addition, microbubbles with different shell elasticity are prepared, and their subharmonic responses are measured in vitro. The results of theoretical calculation and acoustic measurement show that good subharmonic enhancement can be obtained by using the encapsulated microbubbles with the mean size of 3 μm, which were prepared from the surfactant solution with the proper ratio of shell material. It is also shown that the best operating acoustic pressure is 200 to 400 kPa for nondestructive subharmonic imaging based on such kind of microbubbles.