Papers by Keyword: Calculation Model

Abstract: This research work investigates the problem of air pollution with fine dust РМ₁₀ using the city of Kabul as an example. Data from environmental pollution monitoring data during the transition period of March, April and May has been analyzed. The calculation model for РМ₁₀ is obtained depending on three factors: wind speed, humidity and air temperature. The dust concentration was described using the theory of stationary random functions. For the maximum daily concentration of РМ₁₀ in Kabul, estimates of the parameters of the distribution functions were determined, a density function and an integrated distribution function were obtained as well. It is shown that, according to Chi-square and Kolmogorov-Smirnov criteria, the best distribution law of maximum daily concentration of dust is the normal law.

Abstract: The paper presents the results of the assessment of atmospheric air pollution with fine dust РМ₁₀ studies in the city of Kabul_. The investigation was based on concentration of fine dust РМ₁₀ measurements that were conducted by the national agency on ecology and environmental protection of Afghanistan and by Russian researchers in summer and autumn of 2015. It is shown that, according to the Chi-square and Kolmogorov-Smirnov criteria, the best law for the distribution of the maximum daily dust concentration is the logarithmic normal law. For the maximum daily concentration (РМ₁₀) a density function and an integrated distribution function have been summarized. A mathematical model of the concentration of fine dust (РМ₁₀) dependence of three factors: wind speed, humidity and temperature have been obtained. On the basis of F–Fisher criterion the quadratic model has been chosen for June and August, and the linear model has been chosen for July, September, October and November.

Abstract: In article the calculation model of the reinforced crushed-stone-sand basis of pavement with the variable module of elasticity changing on layer depth on exponential dependence is offered. The calculation model is based on representation of the reinforced layer of granular material as the multilayered plate consisting of any quantity of the continuous layers which are rigidly connect among themselves. The method of calculation of the reinforced bases of pavement leaning on experimental data is offered. A concrete example of calculation is reviewed.

Abstract: Carbon emission has become a global focus. The construction of carbon emissions calculation model is helpful for its control. Currently, there is still no uniform method about accounting on the carbon emissions of steel products. The common calculation models are not totally suitable for China. To make up for the shortcomings of them, this paper defines the life cycle system of the iron and steel products based on EIO-LCA, measures the quantity of the direct, indirect carbon emissions and carbon emission deduction in various stages of this life cycle, identifies the hotspot and department which contributes most in carbon emission, and takes Hunan Valin Xiangtan Iron and Steel Co., Ltd (abbreviated Xiang Gang) as an example to validate it. It shows that 2103.87kg of carbon in total would be emitted when one tonne of steel is produced by Xiang Gang. Among the total, the quantity of direct, indirect and deductible carbon emission are 2033.5kg, 216.75kg and 146.38kg respectively, namely carbon emissions of producing per ton of steel is 2.1 tons. Direct carbon emissions from all stages of the life cycle of steel products mainly exist in the stage of steel production and transportation. And ferrous metal smelting and rolling processing industry are the largest emissions industries of the total indirect emissions. Converting by-product gas, heat, and pressure into electrical energy use can reduce carbon dioxide emissions by 146kg, which is the equivalent of reducing carbon dioxide emissions per ton of steel 0.15 tons. Therefore, in order to make the carbon dioxide emissions reach the advanced domestic level of 1.7 tons per ton steel, the iron and steel enterprises can meet emissions reduction targets by strengthening control of carbon emission and improving the efficiency of the utilization of secondary energy from small and large scale.

Abstract: Investigation of mechanical state of shape memory alloy pipe-coupling had an important significance in engineering field. Theory of plastic deformation was used to analyze the coupling force in the tube connecting process of NiTiNb shape memory alloy, in this paper. Based on the analyzed results a mechanical modeling and formula calculation were carried out, the radial pressure of the SMA tube was calculated, in this paper. The results show that, when the temperature doesn’t reach to contact temperature, the pipe coupling of TiNiNb shape memory alloy has no radial pressure; when the temperature reaches to inverse martensite phase transformation temperature, the radial pressure increases; with the decreasing of temperature, the radial pressure increases a little. The radial pressure and push-out force increase with the increasing of the wall thickness. Thus, to improve the strength of connection, the wall thickness of pipe coupling can be properly increased.

Abstract: In different geographical conditions all kinds of failures due to lightning stroke occur in 220/110kV transmission lines. In the high resistivity region lightning back-flashover mainly occurs. This paper, according to the idea of the application manual of 220(110kv) transmission line typical design program put forward by the State Grid Corporation, analyses the width of the corridor, steel consumption of tower, lightning effects, operation and maintenance, and the State Grid recommendation on Shangzi-tower, Portal steel tower, Cup-type tower, Cat-head type tower and Ganzi-tower. And study on Cup-type tower and Cat-head type tower is furthered. Considering various factors, ATP/EMTP method is finally adopted to simulate the lightning withstand level and back-flashover trip rate of two types of tower. The results show that, taking the grounding resistance of 25Ω condition, the lightning back-flashover performance of cup-type tower is slightly better than the cat-head type tower with the same parameters.

Abstract: Original defects in the envelope material easily torn damage under overpressure, when the stratospheric airship in use. This paper based on linear elastic theory studied the tear strength of envelope material containing initial center crack and proposed theoretical model for this problem. Choose Vectran fiber as a reinforcing layer of stratospheric airship envelope material, Combined with digital speckle method measuring tear strength of envelope materials containing different initial center crack length. Comparative analysis found that the theoretical model applicable to estimate the tear strength of envelope material, that center initial crack width ratio is less than 50%.It estimation error within 5% .It satisfies the requirement of engineering application accuracy.

Abstract: A valid mathematic model is introduced to study the calculation of gear meshing transmission error, which is based on the manufacturing error and gear teeth deformation. Subsequently, take a pair of specific gear for example;The transmission error curves are obtained by the calculation model. The results show great consistency with the curves from Romax software, which indicates the validity and high accuracy of the mathematic model presented above. And it can be found that the shape change of transmission error curves affected mainly by the pitch error under the same conditions as the precision.

Abstract: The high way with its characteristics of high flow, fast, safe and comfortable, has played an important role in road traffic. In this paper, based on the maximum-flow algorithm, study on the traffic capacity of highway. Firstly, explain the basic theory of highway traffic capacity.Then, focusing on the method of maximum-flow algorithm to calculate the highway capacity, convert it into usable calculation mathematical model, explain the problem and cite an example.Finally,summarized the full text of the research work. The main research achievements and innovation in this paper is studying the highway network capacity from the macro level, use a quantitative study on the highway traffic capacity of the network.

Abstract: Consumption growth trend of China energy is obvious, and the situation of energy shortage is serious. How to effectively use low energy to optimize the energy structure is one of the important issues in current research field of high efficiency and energy saving. In this paper, the fan is machinery by rotating shaft driven flow with a plurality of blades. From the overall situation, we analyze the fan wing structure characteristics. According to the fan aerodynamic performance and the k-ε model for numerical simulation, we proposed an improved GAMBIT simulation model and analyzed the simulation values for-360 degrees fixed angle of attack and different angles of attack. Finally we get the performance of the fan effect with different angles of attack, and it provides technical and theoretical support for the practice of the area in a certain extent.