This article introduces the method of selection and related criterion of standard copper-cylinder, and systematically analyzes five factors that affect the measuring uncertainty of standard copper-cylinder: primary pressure standard, height measuring of copper-cylinder, and inconsistent individual deformation of standard copper-cylinder, inconsistent pressure sensitivity and the influence of temperature. According to usage characteristics and selection methods of the standard copper-cylinder, discusses computing method of components of the measurement uncertainty and models measuring uncertainty of standard copper-cylinder. The model can quantitatively calculate through experimental data of selection, which lay a theoretical foundation for the control of the pressure measuring uncertainty of standard copper-cylinder.
In order to solve the problem of low accuracy of high-rise building cost evaluation, the author proposes an intelligent evaluation method of engineering cost feasibility model based on the Internet of Things. According to the overall investment composition of the construction project, this paper classifies the cost index, determines the overall cost correction coefficient, and uses the gray correlation analysis method to build the evaluation index system; according to the structure of BP neural network, the network error is calculated, and the error signals of output layer and hidden layer are defined by gradient descent method to obtain the network weight adjustment formula; finally, this paper uses the adaptive learning rate adjustment formula to set the network parameters, introduces the key parameters in the construction project to the input layer, and establishes the final cost evaluation model. Experimental results show that the error rate of this system is controlled within 10%, which meets the requirements of investment estimation. Conclusion. The proposed method can accurately and quickly evaluate the best solution for the cost of high-rise buildings with less information and has strong nonlinear information processing capabilities.
some reservoir property change which occurs during reservoir development has been studied, however, the study about the effect of test mode on stress sensitivity evaluation of full-diameter volcanic rock is few since the volcanic gas reservoir in Da-qing is buried deeply and the properties and flow mechanics are extremely complex. Therefore, there are two different test modes for stress sensitivity to study the effect of test mode on stress sensitivity evaluation. One of the test modes is to keep the internal pressure constant and change the confining pressure and the other is to change the internal pressure and keep the confining pressure constant. The study results are as follows: (a) the permeabilitys variation law at different test mode is similar when the net stress varies. There are two type, one is sensitive with high permeability since for well development of micro-fracture and pore connectivity, the other is not sensitive with high permeability since for the weak pore connectivity and micro-fracture; (b) the permeability could decrease with times of pressure cycling , so, the times of flow/shut in operation should be decreased as few as possible; (c) the relative variation of permeability in the mode of changing confining pressure is smaller than it in changing internal pressure, which means the stress sensitivity of changing confining pressure is weaker; (d) the results of changing internal pressure should be used since the test mode is more similar with the actual operation. The results are significant for gas-water RPs accurate determination and efficient development of volcanic reservoirs.
Based on European Standard EN441-2, an experiment system for measuring the thermal properties of refrigerated display cabinet is designed and constructed. Considering the practice requirements from user, the air distribution analysis is doing under various air-flow form in the testing room. This paper uses the FLUENT, which is one of the CFD simulation software, to verify the design method of air movement. Finally a series of tests required for laboratory quality regulation have been done and the data of velocity or temperature is under the new requirement.
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