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[单选题]
当沉淀池容积一定时,降低池深,会导致()。
A.沉淀效率降低
B.沉淀效率提高
C.沉淀效率不会改变
D.表面水力负荷增大
查看答案
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A.沉淀效率降低
B.沉淀效率提高
C.沉淀效率不会改变
D.表面水力负荷增大
根据气力输送的特点,降低动力消耗,节约能源是一个重要的研究课题,从经验中知,管道内径是关于能耗的重要参数。直观上看,当输送量一定时,管径过小,输送易阻滞,管径过大,虽输送畅通,但又造成能量的浪费。根据经验,把管径分成三组,各组的试验结果如下表所示,试用方差分析法比较各组的效果.
管径(mm) | 单位功耗 |
230 | 0.0308,0.0476,0.0504 |
250~260 | 0.0532,0.032,0.0218,0.028,0.028, 0.042,0.0336,0.042,0.042,0.028 |
280~320 | 0.07,0.07,0.0644,0.0312,0.0756,0.0756, 0.07,0.0588,0.0588,0.042,0.0308,0.0364, 0.0448,0.21,0.154,0.1064,0.1288,0.112, 0.1064,0.1288,0.0756,0.0644,0.0504,0.0644, 0.0504,0.0308 |
A.当城市警察局被认为不负责时,偷盗的受害者们不愿向警察报告偷盗事故。
B.市长的批评者们一般同意认为警察局关于犯罪报告的统计资料是关于犯罪率的最可靠的有效数据。
C.在警察部门进行过类似重组的其他城市里,报告的偷盗数目在重组后一般都上升了。
D.市长对警察系统的重组所节省的钱比预期目标要少。
E.在重组之前的4年中,与其他犯罪报告相比各种偷盗报告的数目节节上升。