Error analyses of filling control systems for liquid amount-given
It is of instructive significance to systematically analyze the factors that influence the precision of filling control systems for liquid amount-given. The sources of additional errors of volumetric flowmeter and Coriolis mass flowmeter were analyzed in the paper. The factors that influence the filling overshoot and lead to overshoot error were discussed in particular. Then the general system error was expressed and the main approaches to improving the filling precision were summarized. It is indicated that the filling precision of system is mainly decided by the precision of flowmeter and other instruments such as thermometer and manometer on condition that the valve is shut off in advance under low instantaneous flowrate. The influence of overshoot error on the filling precision of system is not remarkable.
The identification of external factors which influence the calibration of Coriolis massflow meters
Abstract It has been suggested that, by monitoring the sensor signals and the meter drive signal, it may be possible to create a Coriolis meter which can identify the presence of a variety of external disturbances and can give a warning and/or make a correction to the meter output in order to maintain accuracy. This paper presents the findings from an investigation of the response of commercially available Coriolis meters to such disturbances. The results of this program of tests are reported and the implications of these results on the practicality of the creation of an ‘intelligent’ meter are discussed.
Using Fuzzy-Delphi technique to determine the concession period in BOT projects
BOT projects are affected by several risks and uncertainties. One of the most important issues in this type of contract is to determine the length of concession period considering these uncertainties. The previous studies have developed several models to determine the concession period. However, the uncertainties are not taking into account in most of the previous works. Moreover, none of the previous researches has the capability to aggregate the opinions of different experts being involved in a project regarding the values of the uncertain input parameters. In this research, a Fuzzy-Delphi technique is implemented to determine the length of concession period considering uncertainties. Using the proposed Fuzzy-Delphi technique, the values of different uncertain factors affecting a BOT project is determined considering opinions of a group of experts. The NPV value is calculated considering the resulted aggregated values of uncertain input parameters. Finally, the concession period is determined using fuzzy approach. A case study is conducted to evaluate the performance of the proposed methodology. It is shown that the concession period is determined more effectively using the proposed approach.