输煤系统雨季潮湿煤上仓风险优化控制

结合某发电公司输煤系统工艺流程及来煤煤质状况,阐述雨季潮湿煤上仓的负面影响及风险控制优化策略,以降低落煤管、原煤仓堵仓几率,控制潮湿煤对锅炉稳定燃烧的影响,避免锅炉因堵仓导致停炉事故.     

探索国企核定储备资金的方法

国有企业的物资储备资金,既是保证企业生产经营正常进行的前提,又是加速流动资金周转的必要条件。要把企业储备资金的定额指标真正“量化”,并落实到物资品种上,就应该有正确的核算方法。葫芦岛锌厂的实践证明,统计核算法能够适应国企对储备资金定额的科学管理。     

旬降雨径流非线性模型及其应用研究

通过分析旬降雨、旬初土壤蓄水状态、旬径流信息之间的关系,借鉴短期降雨径流相关模型的思想,建立了一个旬降雨─旬土壤蓄水量─旬径流的非线性相关模型.将该模型应用大伙房水库流域,模拟预测结果令人满意,结果表明该模型简单,可操作性强.将为应用美国的GFS预报系统和中国气象局的213模式10～15 d降雨预报信息,预报旬径流量提供一个有效方法.     

安全指数考核供电企业安全指标的优劣分析

结合供电企业当前的安全管理现状,提出了用安全指数考核供电企业安全指标的建议并详细介绍了安全指数的计算方法。结合实际,用数据和图表对比分析了安全指数与安全天数两种考核方法的优、缺点,最后得出结论:安全指数考核供电企业安全指标能客观、准确地反映企业的安全管理水平。     

基于相似日和多集成组合的短期负荷预测

针对短期电力负荷预测精度低、泛化能力弱等问题,提出了一种基于相似日选取与多集成组合的短期电力负荷预测模型.首先利用最大信息准则MIC(maximal information coefficient)选取高相关变量作为模型输入;然后综合考虑MIC与灰色关联度,对气象敏感性较弱地区的负荷进行相似日选取;最后引入集成随机子空...     

35 kV及以下户外电缆雨天试验装置研制和应用

长期以来,35 kV及以下电压等级户外电缆难以在雨天进行试验.在分析雨天户外电缆试验现状的基础上,针对存在的主要问题,研制出了适合雨天的户外电缆试验装置.重点介绍该装置相对原试验装置的高压引出线改造,装置容量的提高以及增设的支撑铜排及配套避雨措施.一系列应用结果说明该装置实用效果良好.     

Association of days in close up,gestation length,and rumination around time of calving with disease and pregnancy outcomes in multiparous dairy cows

The purpose of this study was to evaluate the effect of rumination times and days spent in a close-up group before calving (DCU) on early-lactation health and reproductive outcomes in dairy cows. Data were gathered for 719 cows located in a single herd. Herd management and reproductive records were analyzed for cows receiving treatment in the first 30 d of lactation (days in milk; DIM) for clinical mastitis, reproductive tract disease, ketosis, milk fever, and displaced abomasum. Rumination times for each cow were downloaded daily from the herd's automated collar system used to generate heat and health alerts for each cow beginning at 21 d precalving until 14 d postcalving. During the first 30 DIM, 121 cows (18%) developed at least 1 disease—any combination of ketosis (40 cows, 5.9% of total), mastitis (17 cows, 2.5%), metritis (75 cows, 11%), milk fever (17 cows, 2.5%), or displaced abomasum (28 cows, 4.1%); 305 cows (45%) were pregnant again at 100 DIM, and an additional 139 cows (20%) were pregnant at 150 DIM. Principal component analysis was used to determine the relationship between gestation length and DCU and their association with the odds of developing disease in early lactation. We did not find any significant association between precalving rumination time and disease within the first 30 DIM. Higher rumination time in the week before calving was shown to be strongly linked to a shorter time to subsequent pregnancy, whereas rumination times postcalving were not associated with changes in the time to pregnancy. Principal component analysis showed that a curvilinear combination of gestation length and DCU (principal component 1) was significantly associated with changes in disease incidence in the first 30 DIM. Gestation length and time spent in close up are important management factors in reducing the incidence of disease in early lactation, and rumination times around calving may help predict future reproductive outcomes.     

近57年山东省降水量及雨日变化特征

基于山东省1961—2017年21个气象站点的降水资料,采用线性回归、空间插值、滑动平均和小波分析等方法分析了57 a来山东省年、季降水量和雨日的时空变化特征。结果表明:山东省降水量和雨日整体呈现自南向北递减的纬度地带性和自东向西递减的经度地带性,高值中心都出现在泰山地区。春、夏两季的雨日和年雨日空间分布相似,冬季雨日呈“东北-西南递减型”分布;年降水量的减少速率为-16.28 mm/(10 a),年雨日以-2.16 d/(10 a)的速率显著下降(通过了0.05的信度检验),两者都存在约17 a的年代周期变化;春季降水量呈微弱增加趋势,和雨日趋势相反,其余三季的降水量和雨日都为负趋势,且夏季降水量和雨日的负趋势通过了0.05的信度检验。年尺度和季尺度下,雨日的负趋势都比降水量的负趋势强度要大,空间范围更广。研究成果可为山东地区水资源规划利用提供合理依据。     

浅谈HDPE高密度聚乙烯缠绕管施工方法

从永春县污水处理厂配套管网工程采用HDPE高密度聚乙烯缠绕管的施工安装出发，对管道施工安装的方法和夏季、雨季施工中出现问题的处理方法进行介绍。