灰色系统理论在烟台市区大气环境质量分析和预测中的应用

利用灰色系统理论对烟台市区大气环境污染因子(SO2、NOx、TSP)数据序列和大气质量综合指数数据序列进行灰色关联度分析,并预测了未来5年内烟台市区大气环境质量状况。结果表明:影响市区大气环境质量的主要污染因子是TSP,其次是SO2;未来5年内烟台市区大气环境质量将逐年提高,且均保持在清洁水平。     

风筛式清选装置筛下物料分布规律研究

为揭示筛下物料分布随清选装置结构、运动参数变化规律,在QXS-3.0型谷物清选试验台上进行了不同风机转速、风机风向角、曲柄转速、曲柄直径的振动筛下物料分布试验。通过分析不同条件下筛下各物料含量及沿筛面横向、纵向分布情况,得出筛下籽粒重量、杂余重量、物料总重量及含杂率沿筛面横向、纵向分布规律。结果表明,物料在横向上分布极不均匀,荞麦籽粒主要分布于籽粒收集箱中间位置,两侧分布较少;因受风机布置影响,杂余量呈“人”字形分布;而筛下物料含杂率呈“w”型分布,且随各参数变化明显。在纵向上,物料分布也不均匀,荞麦籽粒主要集中于籽粒收集箱中间位置,而前端、后端分布较少;杂余量、含杂率曲线近似,杂余量、含杂率在籽粒收集箱0~1 100 mm区域内增长缓慢,1 100~1 500 mm区域增长迅速。所得结论可以为荞麦清选装置的设计及优化提供理论依据,同时对指导农业生产也有重要意义。     

气吸式残膜回收机集膜装置改进设计与试验

针对残膜回收机回收后的残膜含杂率高难以利用的问题,改进设计一种兼具膜杂分离和残膜收集功能的集膜装置。对残膜与杂质在气流场中的运动规律进行分析,探明物料运动轨迹的影响因素。以离心风机转速、隔板到输膜入口距离、隔板高度为试验因素,以含杂率为试验指标进行田间试验,结果表明各因素对含杂率的影响由大到小为：隔板距离、离心风机转速、隔板高度。利用Design Expert软件响应曲面图,进行综合影响效应分析,得出离心风机转速1 974 r/min,隔板距离767 mm,隔板高度723 mm,在此参数条件下含杂率为6.97%。研究结果可为残膜回收设备研发提供依据。     

控制通风和日粮中添加丝兰宝对改善羊舍空气质量效果的研究

对三栋密闭式羊舍内的空气环境状况进行了观测及分析,研究日粮中添加丝兰宝和通风两种方式改善羊舍空气质量的效果。结果表明:对照组、通风组和丝兰宝组舍内氨气平均浓度分别41.06 mg/m33、1.43 mg/m3和30.65 mg/m3,其中通风组和丝兰宝组极显著低于对照组(P<0.01),通风组与丝兰宝组之间差异不显著(P>0.05);硫化氢平均浓度分别为0.0037mg/m30、.0034 mg/m3和0.0039 mg/m3,三组间差异不显著(P>0.05);二氧化碳平均浓度分别为1 843 mg/m31、523 mg/m3和1 718 mg/m3,三组间差异不显著(P>0.05)。舍内温度通风组显著低于对照组(P<0.05),湿度通风组和丝兰宝组显著低于对照组(P<0.05),粪便含水量通风组显著低于对照组和丝兰宝组(P<0.05),TSP、PM10浓度三组间差异不显著(P>0.05)。表明控制通风和在日粮中添加丝兰宝均能明显改善羊舍空气质量。     

Efficacy of urease inhibitor to reduce ammonia emission from poultry houses

As the poultry industry has grown, so have concerns about the environmental management aspects of these industries, including air and water quality. Poultry operations continue to expand and are large contributors to farm income. There is increased concern related to ammonia emission from poultry operations. Various abatement methods, including dietary manipulation, chemical amendment of litter, and improvement in ventilation system management have been used to control ammonia concentrations from livestock facilities, but these methods are perceived to be too expensive, to impair bird growth, or to add to pollution in some other form. Alternative strategies include reduction of ammonia emissions by arresting N in the litter. An alternative approach to decrease ammonia emissions in poultry facilities is to block the enzyme activity in the litter because ammonia is the by-product of a 5-step enzymatic degradation of uric acid. Our preliminary study with layer feces, which were allowed to accumulate on a layer of broiler litter, indicated that a commercially available urease inhibitor resulted in a significant reduction in equilibrium ammonia concentration over time. Based on the results of the preliminary experiment, further studies were conducted to study the effect of the urease inhibitor on broiler litter and layer feces directly. The results showed that the urease inhibitor did not have any effect on equilibrium ammonia concentration when applied to drier broiler litter. The reduced moisture content in the broiler litter may have inhibited urease inhibitor activity. With layer feces, urease inhibitor reduced equilibrium ammonia concentration. The effect of the first application lasted for 1 wk, after which the equilibrium ammonia concentration in the treated trays rebounded to exceed that of the control trays. Upon a second application of urease inhibitor, the effect lasted for 14 d. The difference in the effect of the urease inhibitor on equilibrium ammonia concentration upon first and second application could have been influenced by a change in manure characteristics over time. Layer manure is a dynamic environment with continued change; therefore, more research is warranted in the area of stored layer manure.     

不同干燥方式对芒果果皮理化特性的影响

采用热风干燥、远红外干燥和微波干燥处理芒果果皮,探讨不同干燥方法对芒果果皮理化特性的影响.结果表明:微波干燥的芒果果皮干基含水率下降程度和干燥速率都优于热风干燥和远红外干燥,但复水性较差;3种干燥方法对果皮色泽及总多酚、总黄酮和色素含量的影响各有差异.通过对干燥芒果果皮收缩率、复水性、色泽及总多酚、总黄酮和色素含量进行主成分分析,得出远红外干燥的主成分综合得分最高,此干燥方法更加适合用于干燥芒果果皮.     

Analysis of Fire Smoke Movement with Different Air Velocity at the Stair head to the Hall of a Metro Station

When a fire happens at the subway platform, the downward ventilation at the staircase which connects the hall and platform can prevent smoke spreading into the hall and provides guiding air for evacuation people. To investigate the influence of the ventilation rate on the smoke movement, the air velocity at the staircase was measured under three ventilation modes. Numerical model was established to simulate the real fire scenario. It is shown that the downward air velocity under fire is greater than that without fire, and the traditional design procedure without considering complex factors interaction in real fire scenario should be improved; when fire is near the staircase, smoke easily spills from the smoke screen to the concourse. And smoke concentration of concourse is even higher than that of platform because the hall is under air supply mode; when the fire locates at the public area of the platform, turning on the tunnel fans can increase the downside flow at the staircase. However exceeding high flow can produce disturbance and destroy the smoke stratification, so more area will be filled with smoke. Therefore, reasonable smoke management scheme is as important as smoke exhausting system capability.     

The Influence of Air Inlet on Ventilation Effect in Indoor SubstationTransformer Rooms

Ventilation design is the difficulty of transformer room design. Temperature field and velocity field in a transformer room was simulated by CFD method . By comparing simulation value with the experimental value in related document , the effectiveness of the mathematical model was verified. Based on it, an indoor substation transformer built was taken as the simulation object, then designed and simulated six kinds of ventilation condition by changing the location and area of air inlet, focused on the influence of air inlet on the ventilation effect by comparing the temperature field ,velocity field and temperature characteristic value in different condition. The simulation results show that when air inlet area is fixed, the air inlet should be arranged in the radiator side and its center height should be controlled in the radiator center height or slightly offset position, it should not be higher than the radiator. When the air inlet location is fixed, air inlet area should be increased along the high direction to improve ventilation effect. The conclusions can provide technical support for the ventilation design of transformer room.     

The Effect of Admixture on Drying Shrinkage of AlkaliActivated Slag Mortar

Experiment study about the effect of different admixture on drying shrinkage of alkali-activated slag mortar. The results show that shrinkage reducing agent has some inhibit effect for the drying shrinkage of alkali-activated slag mortar. However, air entraining agent, Na2SO4and Ca(OH)2 made the drying shrinkage of alkali-activated slag mortar growth.     

Influence of rain on AC discharge characteristic of rod-plane(rod-rod) air gap

As flashover accidents because of strong wind and storm frequently appear in our country, storms are thought to be one cause of flashover between tower and conducting wires in transmission lines.The influence of rainfall intensity,rainwater resistivity and air temperature on AC discharge characteristic of rod-plane(rod-rod) air gap is mainly investigated.The experimental result shows that,rainfall intensity and rainwater resistivity can reduce AC discharge voltage of rod-plane(rod-rod) air gap,and rainfall intensity has the most obvious effect on AC discharge voltage of rod-plane air gap;when rainfall intensity ranges from 2 to 14 mm/min,AC discharge voltage maximum reduction of 0.4,0.6,0.7 m rod-plane gap is respectively 6.73%,6.54%,6.02%,and maximum reduction of rod-rod gap is respectively 2.66％,3.22%,3.07%;the influence of rainfall intensity on AC discharge voltage of rod-plane is bigger than rod-rod’s;AC discharge voltage of rod-plane air gap increases with the increase of air temperature,and the maximum amplitude is 7.03%.