Reliability Analysis of Reinforced Concrete Beams Strengthened with CFRP Sheets

The uniaxial load tests were conducted to investigate the material behavior of CFRP sheets. The results show that the probability distribution of CFRP tensile strength can be described by the three-parameter Weibull distribution. The design formulae for determining flexural capacity of reinforced concrete strengthened with CFRP sheet are proposed. The Monte Carlo procedure was applied to simulate the flexural capacity of reinforced concrete strengthened with CFRP sheet. By using the JC method, the reliability index was calculated based on the statistics of flexural capacity and load effect. After the analysis of the effect of the partial factor of CFRP sheet on the reliability index, the results reveal that the reliability index of all design points are the most close to target reliability index overall when the partial factor of CFRP sheet is 1.25,and in this condition the reliability index of three flexural failure modes achieve the target reliability index respectively. Therefore, the partial factor is suggested to be 1.25, which meets the requirement of reliability design.     

Application of multivariate statistics in model experimental analysis of air cushion towing of 4-suction anchor platform

This paper coducts model tests on a 1∶20 scaled model of four-suction anchor platform. The acceleration, the internal air pressure, the bottom water pressure of the suction anchors and towing force of the suction anchor platform are determined in series of towing combinations with different wave direction, wave velocity, wave period, towing velocity, towing points, towline length and tilt angle. Cluster analyses are used to classify the combinations of towing and factor analyses one used to analyze the mechanical characters. The correlative matrix is obtained which can reflect the correlation of mechanical characters. The factor analysis results show that 85% the total variance is attributed to the former six factors, and the factor scores of the towing combinations was obtained to find the most disadvantageous combinations and the mechanical characters which can lead to the disadvantageous results. The analysis results can be used for consulting the practical application.     

An agronomic, economic and behavioral analysis of N application to cotton and wheat in post-Soviet Uzbekistan

Cotton and winter wheat play a vital role in Uzbek agriculture: the first crop is a vital component of the national export revenues, while the latter is key in achieving independence from grain imports. Due to these strategic roles in the national economy, both crops are part of the state procurement system and, hence, are subject to strict regulations imposed to ensure budget revenues and self-sufficiency. However, many factors cause the divergence of crop yields from their technically maximum levels. We analyzed those factors, which hamper achieving the optimum response to fertilizer applications. In a stepwise procedure, we (i) reviewed the technical and financial optimum yield responses of cotton and winter wheat production to fertilizer applications and (ii) analyzed the changes of fertilizer-to-product price ratios to shed light on the agronomic and economic performance of cotton and wheat in the post-Soviet agricultural system of Uzbekistan. The analysis combined data from long-term, historical yield and fertilizer responses, agronomic N-fertilizer response experiments, and socio-economic farm surveys. Quadratic yield-response functions were used to derive economic and technical optimum rates of N-fertilizer applications. Based on the parameterized function and fertilizer-to-product price ratios observed for 1996-2003, we analyzed the difference between recommended fertilization and economic optimum application rates. Results showed that under the state procurement system, Uzbek farmers may not necessarily tend to maximize the profits from their cotton and wheat production. The level of subsidies and the differential crop support by the state induce farmers to follow the official fertilizer recommendations to ensure that they fulfill the production targets even if it implies higher production costs. The present gaps between the officially recorded yields and those technically achievable given the agro-ecological conditions in Uzbekistan cannot be narrowed by only improving N-fertilizer management. It would require additional efforts to improve cotton and wheat yields.     

花江峡谷示范区主要经济植物病虫害及防治对策

经过野外调查与初步鉴定整理，花江峡谷喀斯特石漠化综合防治技术示范区，花椒病虫害26种，金银花病虫害3种，石榴病虫害10种，砂仁病虫害1种，葡萄病虫害3种，对主要病虫害提出相应的防治对策。     

伐区造材的价值工程

本文运用价值工程的理论和方法,查找伐区造材原木价值损耗的主要原因,并分析了增加伐区造材经济效益的措施。     

谷物复合培养基栽培金针菇试验及其菌糠的营养价值分析

用谷物复合培养基栽培金针菇可获得较高的产量。且菌糠可替代玉米配制畜禽饲料,为养殖业的饲料来源开辟一条新途径,节省大量粮食和资金,取得较好的经济效益。     

红松疱锈病防治指标的研究

在红松人工林疱锈病(Cronartium ribicola)综合防治技术研究基础上,又对不同发病林分累积3年病情损失、各项防治措施的效益和成本进行了分析,确定林分发病率5％为该林分红松疱锈病的经济阀值。因此防治指标是:林分发病率在5％以下时可以不防;林分发病率在5％—9.5％时,采用修枝结合药防措施(修除1.5—1.8 m以下侧枝,松焦油+柴油涂干防治);林分发病率在9.5％以上时,应用间伐+修枝+药防措施(间伐强度20％—30％,然后修技和药剂防治。这样应用该指标管理病害,以3年为一个防治周期,可获显著的防治效果和经济效益。     

带分离装置削片机的研制

介绍了带分离装置削片机的整机结构，设计特点和工作性能，并分析了采用该削片机所能产生的经济效益，其结论是，此削片机性能优良，结构先进，有广阔的推广前景。     

浅谈闽北山地经济林发展的思路与对策

闽北林区在山地综合开发、发展经济林方面,取得一定成效,但也存在品种、质量、规模、加工、销售等深层次问题。本文阐述闽北经济林发展的现状、问题,并提出相应对策,以供参考。     

南江黄羊与陕南白山羊的杂交效果

本文总结了安康地区开展南江黄羊与陕南白山羊杂交试验的效果。统计表明 ,南江黄羊与陕南白山羊的杂交一代生长快、体格大、耐粗饲、适应性、抗病性强 ,各阶段体重均明显高于陕南白山羊 ( P<0 .0 1 )。其周岁平均体重 ( 35 .5 4± 1 .75 kg) ,全期平均日增重 ( 91 .8g)分别较陕南白山羊提高 35 .1 %和 35 .8%。其体重的杂交优势率达 2 0 .3% ,能够达到当年出栏的要求 ,且平均每只杂交一代羊较陕南白山羊经济收入增多。