通过对杭州卷烟厂两台35/10 k V主变、6台10 k V制冷机和11台10/0.4 k V变压器负荷的实测,分析变压器和制冷机负荷率低的原因。指出要想使今后的设计容量接近实际,首先应修正并细化YC/T 9-2006《卷烟厂设计规范》的第9.2.2条,使制丝车...通过对杭州卷烟厂两台35/10 k V主变、6台10 k V制冷机和11台10/0.4 k V变压器负荷的实测,分析变压器和制冷机负荷率低的原因。指出要想使今后的设计容量接近实际,首先应修正并细化YC/T 9-2006《卷烟厂设计规范》的第9.2.2条,使制丝车间、卷包车间和掺兑车间需要系数Kx更接近实际。对车间冷负荷计算中涉及工艺设备散热量的计算,可参考文章《电动设备冷负荷计算新方法》,使得以电动设备冷负荷为主的空调车间,设计冷量、风量和水量(冷却水量和冷媒水量)比较接近实际。从而大幅度减小变压器的设计容量。展开更多
Geothermal power plants are receiving increasing attention as regards the mobilization of mercury （Hg） to the environment. Hg is a trace element that may be present in the geothermal fluid, but due to its volatility...Geothermal power plants are receiving increasing attention as regards the mobilization of mercury （Hg） to the environment. Hg is a trace element that may be present in the geothermal fluid, but due to its volatility, it is transferred mainly into the vapor phase. Hence, it may be mostly discharged to the atmosphere with the non-condensable gases. Olkaria geothermal field hosts 3 geothermal power plants. In this area Hg deposition fluxes have not been studied. Concentrations and wet deposition fluxes of total mercury （T-Hg） were determined from April 2009 to May 2010 at 2 sites in this field. Event-based precipitation samples were collected using fabricated bulk precipitation samplers. Samples were treated according to trace metal protocol and analyzed by cold vapor atomic fluorescence spectrometry （CVAFS）. This paper thus reports the first ever determination of T-Hg concentrations and fluxes in precipitation. The T-Hg concentration in samples ranged from 0.002-0.0602 μg/L at the two sites, however, the volume-weighted mean concentration and wet deposition flux were 0.01974 and 0.02884μg.L^-1 and 0.0167-1.45 μg.m2 during the study period. The annual volume-weighted mean wet deposition fluxes of T-Hg for 2 sites were 13.74 and 19.83 μg.m-2.yr-1 with an average flux of 16.785μg.m-2.yr-1. Hg concentrations and the Hg fluxes in precipitation showed seasonal trends being lowest in the short-rains and highest in the long rains. The concentrations of T-Hg for the 2 sites is negatively correlated with the precipitation depth （r2 = 0.26 ＆ r2 = 0.0065）, suggesting that scavenging of particle-bound mercury from the atmosphere is an important mechanism contributing to mercury in rainwater. Mean Hg concentrations in precipitation at the study sites were comparable to the ranges reported for Canada and the USA by the Mercury Deposition Network （MDN）.展开更多
Plants can be exposed to mercury either by direct administration as antifungal agents, mainly to crop plants through seed treatment or foliar spray, or by accident. Mercury poisoning has become a problem of interest o...Plants can be exposed to mercury either by direct administration as antifungal agents, mainly to crop plants through seed treatment or foliar spray, or by accident. Mercury poisoning has become a problem of interest on a global scale. Natural emissions of mercury form two-thirds of the input; man-made releases form about one-third. Significant amounts of mercury may be added to agricultural land with sludge, fertilizers, lime and manures. Total mercury levels were determined in six breeds of quality protein maize using cold vapor atomic absorption spectrometry （CVAAS）. The breeds analyzed were Aziga, Abeleehi, Akposoe, Golden Jubilee, Etubi and Obaatanpa. Proximate composition of these breeds was also determined. The objective of this study was therefore to assess the effect of mercury on the proximate composition of quality protein maize. The proximate composition of the maize varieties analyzed showed that the moisture content ranged from 11.57% ± 0.205% to 12.76%± 0.042%, ash from 1.11% ±0.064% to 1.58% ±0.021%, protein, 6.51%± 0.307% to 10.39% ±0.306%, fiber 1.44% ±0.071% to 1.87% ± 0.057%, fat 1.84% ± 0.078% to 2.75% ± 0.092% and carbohydrate 71.77% ± 0.035% to 76.54% ± 0.216%. The total mercury levels in the maize breeds analyzed ranged from 0.0010 ＋ 1.17E-05μg/g to 0.0079 ＋ 1.00E-05μg/g. The mercury levels detected were lower than the WHO limit for mercury in food of 0.5 μg/g in all the maize breeds. The low levels of mercury in the maize samples show they are safe for consumption.展开更多
文摘通过对杭州卷烟厂两台35/10 k V主变、6台10 k V制冷机和11台10/0.4 k V变压器负荷的实测,分析变压器和制冷机负荷率低的原因。指出要想使今后的设计容量接近实际,首先应修正并细化YC/T 9-2006《卷烟厂设计规范》的第9.2.2条,使制丝车间、卷包车间和掺兑车间需要系数Kx更接近实际。对车间冷负荷计算中涉及工艺设备散热量的计算,可参考文章《电动设备冷负荷计算新方法》,使得以电动设备冷负荷为主的空调车间,设计冷量、风量和水量(冷却水量和冷媒水量)比较接近实际。从而大幅度减小变压器的设计容量。
文摘Geothermal power plants are receiving increasing attention as regards the mobilization of mercury （Hg） to the environment. Hg is a trace element that may be present in the geothermal fluid, but due to its volatility, it is transferred mainly into the vapor phase. Hence, it may be mostly discharged to the atmosphere with the non-condensable gases. Olkaria geothermal field hosts 3 geothermal power plants. In this area Hg deposition fluxes have not been studied. Concentrations and wet deposition fluxes of total mercury （T-Hg） were determined from April 2009 to May 2010 at 2 sites in this field. Event-based precipitation samples were collected using fabricated bulk precipitation samplers. Samples were treated according to trace metal protocol and analyzed by cold vapor atomic fluorescence spectrometry （CVAFS）. This paper thus reports the first ever determination of T-Hg concentrations and fluxes in precipitation. The T-Hg concentration in samples ranged from 0.002-0.0602 μg/L at the two sites, however, the volume-weighted mean concentration and wet deposition flux were 0.01974 and 0.02884μg.L^-1 and 0.0167-1.45 μg.m2 during the study period. The annual volume-weighted mean wet deposition fluxes of T-Hg for 2 sites were 13.74 and 19.83 μg.m-2.yr-1 with an average flux of 16.785μg.m-2.yr-1. Hg concentrations and the Hg fluxes in precipitation showed seasonal trends being lowest in the short-rains and highest in the long rains. The concentrations of T-Hg for the 2 sites is negatively correlated with the precipitation depth （r2 = 0.26 ＆ r2 = 0.0065）, suggesting that scavenging of particle-bound mercury from the atmosphere is an important mechanism contributing to mercury in rainwater. Mean Hg concentrations in precipitation at the study sites were comparable to the ranges reported for Canada and the USA by the Mercury Deposition Network （MDN）.
文摘Plants can be exposed to mercury either by direct administration as antifungal agents, mainly to crop plants through seed treatment or foliar spray, or by accident. Mercury poisoning has become a problem of interest on a global scale. Natural emissions of mercury form two-thirds of the input; man-made releases form about one-third. Significant amounts of mercury may be added to agricultural land with sludge, fertilizers, lime and manures. Total mercury levels were determined in six breeds of quality protein maize using cold vapor atomic absorption spectrometry （CVAAS）. The breeds analyzed were Aziga, Abeleehi, Akposoe, Golden Jubilee, Etubi and Obaatanpa. Proximate composition of these breeds was also determined. The objective of this study was therefore to assess the effect of mercury on the proximate composition of quality protein maize. The proximate composition of the maize varieties analyzed showed that the moisture content ranged from 11.57% ± 0.205% to 12.76%± 0.042%, ash from 1.11% ±0.064% to 1.58% ±0.021%, protein, 6.51%± 0.307% to 10.39% ±0.306%, fiber 1.44% ±0.071% to 1.87% ± 0.057%, fat 1.84% ± 0.078% to 2.75% ± 0.092% and carbohydrate 71.77% ± 0.035% to 76.54% ± 0.216%. The total mercury levels in the maize breeds analyzed ranged from 0.0010 ＋ 1.17E-05μg/g to 0.0079 ＋ 1.00E-05μg/g. The mercury levels detected were lower than the WHO limit for mercury in food of 0.5 μg/g in all the maize breeds. The low levels of mercury in the maize samples show they are safe for consumption.
