微调型分流调节器的设计与应用

刀型闸阀是选煤厂应用最广泛的管路截止、调节、导流控制设备,但由于调节频繁,其损坏较快。根据实际工作需要,在制定设计思路的基础上,分析设计需要与可行性,进而制定微调型分流调节器的设计方案,并予以实施。生产实践表明:微调型分流调节器投入使用后,在保证系统流量及入料介质比例合格的前提下,能够有效减少材料消耗和检修时间。

Regression Equations for Predicting the Effect of Tine Width on Draught and Soil Translocation in Moderately Fine Textured Soil

Experiments were conducted in an indoor soil bin filled with sandy clay loam soil. Tests were carried out with tillage tines to study the effect tool width on soil disturbance and draught. Depth of operation was held constant at 35 mm and then at 70 mm while speed was varied at three levels of 1.0, 3.6 and 9.0 km/h. The widths of the tines tested were 10, 20, 31, 40, 51, 88, 126, 163 and 200 mm. The cone penetration resistance of the soil varied from 400 to 600 kPa. Draught was measured with a load cell while soil disturbance was measured with a profile meter and meter rule. Draught increased at a decreasing rate with tine width. Quadratic models best fitted the data points with high R2 values. The increase in draught was affected by the forward speed since higher draught values were obtained at higher speed. Results show that the parameters of soil disturbance increased with increase in tine width, except height of ridge （hr）, which did not show any specific trend. The specific draught was highest （10.63 N/cm） with tine T20 while Tine T1 had the least specific draught of 5.2 N/cm.

Dynamic Economic Dispatch for Microgrids Including Battery Energy Storage

Microgrids integrate distributed renewable energy resources, controllable loads and energy storage in a more economic and reliable fashion. Battery energy storage units are essential for microgrid operation, which make microgird become a strong coupling system in the time domain. Hence, the traditional methods of static dispatch are no longer suitable for microgrids. This paper proposes a dynamic economic dispatch method for microgrids. Considering microgrid as a discrete time system, the dynamic economic dispatch is to find the optimal control strategy for the system in finite time period. Based on this idea, the dynamic economic dispatch model for microgrids is established, and then the corresponding dynamic programming algorithm is designed. Finally, an example of microgrid is given, and the dynamic economic dispatch results are compared with that of the static dispatch. The comparison confirms the effectiveness of the proposed dynamic dispatch method.

Modulation of Soil Particle Size and Nutrient Availability in the Maize Rhizosheath

Root exudates,microorganism colonization and soil aggregates together form the rhizosheath,a special cylinder of micro-ecosystem adhering to the root surface.To study how the rhizosheath affects soil structure and nutrient distribution,we analyzed the impact of maize rhizosheath on soil particle size and nutrient availability in pot and field experiments.The results showed that there was a significant size decrease of soil particles in the rhizosheath.Meanwhile,the soil mineral nitrogen in the rhizosheath was significantly higher than that in the rhizosphere or bulk soil at tasseling and maturity stages of maize.The contents of Fe and Mn were also differentially altered in the rhizosheath.Rhizosheath development,indicated by a dry weight ratio of rhizosheath soil to the root,was relatively independent of root development during the whole experimental period.The formation of maize rhizosheath contributed to the modulation of soil particle size and nutrient availability.The subtle local changes of soil physical and chemical properties may have profound influence on soil formation,rhizospheric ecosystem initiation,and mineral nutrient mobilization over the long history of plant evolution and domestication.

Wind estimation around the shipwreck of Oriental Star based on field damage surveys and radar observations

Based on observational analyses and on-site ground and aerial damage surveys, this work aims to reveal the weather phenomena--especially the wind situation--when Oriental Star capsized in the Yangtze River on June 1, 2015. Results demonstrate that the cruise ship capsized when it encountered strong winds at speeds of at least 31 m s ^-1 near the apex of a bow echo embedded in a squall line. As suggested by the fallen trees within a 2-kin radius around the wreck location, such strong winds were likely caused by microburst straight-line wind and/or embedded small vortices, rather than tomadoes.

A study on integrated design conjugation profiles application analysis of scroll profiles for automobile air conditioning

The research on scroll profiles theory at present mainly is aiming at the single profile and its amelioration or parameter optimization,not aiming at the natural characteristic of the profiles equation of scroll profiles itself.Thus,the intrinsic differential equation bearing on arc-length and tangent direction angle was studied.Using the inherent differential equation and general functional theory,the conversion ideas between the expression of intrinsic differential equation and the expression in Cartesian coordinate was studied,and the condition of involutes characteristic was presented.The detailed analysis of four typical scroll profiles was given.According to the four typical scroll profiles and based on the method of Taylor series,the unified formation of general functional integration scroll profiles was established,which perfected general theory of scroll profiles increasingly.The envelope method to seek conjugation engagement profiles was studied.The unified general functional equation of scroll profiles represented the admissible function scrolls and the conjugation engagement characteristic of which was studied.The engagement condition of conjugation scroll profiles and the expression in Cartesian coordinate of conjugation scroll profiles of general functional integration scroll profiles were educed.Therefore,the restriction of inherent characteristics of single scroll profiles model is broken through.Solid modeling and machine tool path simulation can bridge the gap between design and manufacture which is essential for the design and manufacture of scroll compressors.With this method a perfect solid model can be achieved,which leads to an optimal design in terms of quality,delivery time and cost.The presentation of unified formation of general functional integration scroll profiles represents foundation factor of instinct characteristics of scroll profiles,which widens the design method of scroll compressor for automobile air conditioning.