A MODIFIED RATIONAL FORMULA FOR FLOOD DESIGN IN SMALL BASINS1

ABSTRACT: New formulas and procedures under the framework of the Rational Formula are presented that are applicable to flood design problems for a small basin if the geometry of the basin can be approximated as an ellipse or a rhombus. Instead of making the assumption in the traditional rational formula that the rainfall is uniformly distributed in the whole duration (D_w) of a design storm, the new method modifies that assumption as: the rainfall is uniformly distributed only in each time interval CD) of the design storm hyetograph, thus extending the rational formula applicable to the case that the rainfall duration is less than the basin concentration time (T_c). The new method can be applied to estimate the flood design peak discharge, and to generate the flood hydrograph simultaneously. The derivation of the formulas is provided in detail in this paper, and an example is also included to illustrate how to apply the new formulas to the flood design problems in small basins.     

Formula allocation as a policy tool: politics and measurement

Formula allocation is a major tool for the distribution of public funds in the United States of America. This paper explores several examples of formulae used in U.S. domestic programmes, looking at their construction, meaning and consequences. The authors argue that the design of formulae is both a political and technical task. The paper concludes with a series of recommendations to improve formulae as tools of distributional policy.     

管土刚度对地下管线和地表沉降的影响分析及简易预测方法研究

在地层沉降计算理论基础上,通过定义新的管土刚度系数,以打靶法为手段,计算分析管线的沉降变形趋势,从管线抵抗地层沉降变形的效果可通过增加隧道埋深来体现这一思想出发,找到该系数与假想隧道埋深的相互对应关系,进而建立一套地下管线沉降和地表沉降的简易预测公式。通过与数值解的对比分析,进一步验证了其准确性和合理性。该公式计算量小、模型简单,应用范围较为广泛,可用于计算考虑管土刚度后,管线沉降变形和管线与地层之间的脱空,也可用于计算考虑管线抵抗地层作用后的地表沉降变形。     

中药复合饲料对锦鲤诱食效果与生长影响的研究

选择3种中药配方,以其水提液对体长3-5cm锦鲤进行诱食活性(触球法)试验.每组实验重复5次,实验结果采用Excel和SPSS软件分析.结果表明,配方1对锦鲤的诱食有抑制作用,配方2与配方3对锦鲤有诱食反应,抑制或诱食的强弱与中药的浓度有关.其中,配方1 P=0.004＜ 0.05,配方2 P=0.0005＜ 0.05,配方3 P=0.0003＜ 0.0,经复合饵料饲喂后,实验鱼体长和体重都比基础饵料增长显著,说明3种饵料对锦鲤的生长都有促进作用.其中,配方2降低饵料系数0.2801,增重率达17.66％.     

过滤吸附装置人字形布置公式浅谈

过滤吸附装置是有机废气过滤吸附箱的核心部件，其人（之）字形布置公式系根据工程实践总结出来的计算公式。本文介绍了活性炭纤维吸附装置布置公式的提出背景、推导过程和应用验证，以及采用本公式的优点。     

Arrhenius公式和环境作用动力学对压缩橡胶的精度比较

目的 精确描述压缩橡胶永久变形率的变化规律,准确评估其使用寿命。方法 应用环境作用动力学理论,建立压缩橡胶永久变形率的变化微分方程,求解微分方程得到压缩橡胶永久变形率变化规律的微分方程通解。再以氟硅橡胶为例,通过高温加速试验获取其在100、125、150、175、200℃下的试验数据,分别采用环境作用动力学通解和阿伦尼乌兹公式建立氟硅橡胶压缩永久变形率模型。最后,与3.5 a的自然环境试验数据进行对比。结果 应用环境作用动力学理论建立的氟硅橡胶压缩永久变形率模型与3.5 a自然环境试验数据的最大误差约为3.32%,而应用阿伦尼乌兹公式建立的氟硅橡胶压缩永久变形率模型的最大误差约为14%。结论 阿伦尼乌兹公式只适用于没有环境作用或固定环境作用下的物质特征变化,而环境作用动力学方程中,有明确的环境作用项σ,适用于复杂环境作用下物质特征变化规律的描述。