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81.
82.
针对内燃机车“途中缺水”故障 ,设计并安装临时补水设备 ,解决了电化区段临时补水的问题 ,满足了内燃机车“不停车、不停机”即可补水的要求。 相似文献
83.
使用自粘性防水卷材对带钢副框的铝合金门窗窗边进行粘接,以防止雨水通过副框与墙体之间的缝隙渗漏到室内,重点介绍了详细的施工措施。 相似文献
84.
Periklis E. Ergatis Panagiotis G. Massouros Georgia C. Athanasouli George P. Massouros 《国际能源研究杂志》2003,27(9):795-811
A time‐dependent coefficient of heat transfer is proposed for the computation of thermal power required, so that a room temperature reaches a desired value within a given time. A mathematical formulation of the room heating transient phenomenon is constructed in a dimensionless form. Using an integral approximate solution an analytical expression for this coefficient is provided and it is verified by diagrams adopted by DIN 4701. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
85.
86.
Xinru Xu Jingyi Yang Ying Jiang Jinsheng Gao 《Petroleum Science and Technology》2006,24(11):1307-1321
The efficiency of desalting for six crude oils was studied with a SY-1 dynamic simulation experimental installation. The demulsifier DC2 was examined for 1#, 2#, and 4# crude oil and DC4 was used for 3#, 5#, and 6# crude oil. The effects of temperature, electric field gradient, dosage of demulsifier, and washing water on the desalting efficiency of six crude oils were investigated. The results showed that at the optimization process condition after desalting, the desalting efficiency and the salt content of 1# crude oil reached 89.17% and 1.92 mg/L; that of 2# crude oil reached 85.08% and 1.04 mg/L; that of 3# crude oil reached 91.06% and 1.35 mg/L; that of 4# crude oil reached 81.67% and 1.51 mg/L; that of 5# crude oil reached 81.03% and 2.32 mg/L; and that of 6# crude oil reached 86.64% and 2.67 mg/L. Different crude oils have different metal contents. Three assistants, ammonium nitrate (TJ1), nitric acid (TJ3), and polyamine carboxylate (TJ4), were used to improve the efficiencies of desalting and demetalization of six crude oils. TJ4 was more efficient in removing calcium and iron for 1# and 2# crude oil. TJ1 was more efficient in desalting and demetalizing 5# crude oil. The efficiencies for removal of calcium, iron, nickel, and vanadium respectively reached 99.89%, 98.33%, 20.58%, and 43.02%. TJ3 has better efficiency desalting and demetalizing for 6# crude oil. With the concentration of TJ3 increasing from 0 to 80 mg/L, the desalting efficiency increases from 31.22% to 73.54%, and the iron removal efficiency increases from 56.0% to 74.05%. 相似文献
87.
Effect of electricity tariff on the optimum insulation-thickness in building walls as determined by a dynamic heat-transfer model 总被引:5,自引:0,他引:5
Thermal insulation is one of the most effective energy-conservation measures in buildings. Despite the widespread use of insulation materials in recent years, little is known regarding their optimum thickness under dynamic thermal conditions. Insulated concrete blocks are among the units most commonly used in the construction of building walls in Saudi Arabia. Typically, the insulation layer thickness is fixed at a value in the range 2.5–7.5 cm, regardless of the climatic conditions, type and cost of insulation material, and other economic parameters. In the present study, a numerical model based on a finite-volume, time-dependent implicit procedure, which has been previously validated, is used to compute the yearly cooling and heating transmission loads under steady periodic conditions through a typical building wall, for different insulation thicknesses. The transmission loads, calculated by using the climatic conditions of Riyadh for a west-facing wall, are fed into an economic model in order to determine the optimum thickness of insulation (Lopt). The latter corresponds to the minimum total cost, which includes the cost of insulation material and its installation plus the present value of energy consumption cost over the lifetime of the building. The optimum insulation thickness depends on the electricity tariff as well as the cost of insulation material, lifetime of the building, inflation and discount rates, and coefficient of performance of the air-conditioning equipment. In the present study, the effect of electricity tariff on the computed optimum insulation thickness is investigated. Different average electricity tariffs are considered; namely, 0.05, 0.1, 0.2, 0.3 and 0.4 SR/kWh (designated as Cases 1–5, respectively; 1 US$ = 3.75 Saudi Riyals). Results using moulded polystyrene as an insulating material show that the values of Lopt are: 4.8, 7.2, 10.9, 13.7 and 16.0 cm for Cases 1–5. Under the conditions of optimal insulation thickness for each electricity tariff, Case 1 gives the lowest total cost of 17.4 SR/m2, while Case 5 gives the highest total cost of 53.1 SR/m2. Corresponding thermal performance characteristics in terms of yearly total and peak transmission loads, R-value, time lag and decrement factor are presented. 相似文献
88.
基础锚栓预埋加固方案 总被引:1,自引:0,他引:1
结合工程实例 ,介绍轻钢结构系统基础锚栓预埋、加固解决方案 ,并介绍了加固系统的制作及使用方法 ,可供工程人员参考 相似文献
89.
对高层建筑设计而言,设计前期的初步结构方案需通过结构软件的计算分析,判断该方案是否正确与合理,从而对其进行有针对性的修改和优化。文章结合具体实例,介绍了分析判断计算结果的主要几项内容及可采取的相应优化措施,从而可以提高设计的准确性和工作效率。 相似文献
90.