基于CAXA与MatLab的捡拾臂优化设计与分析求解

捡拾臂是圆草捆捡拾车的核心部件之一,其结构设计的合理性与作业过程的实用性是影响圆草捆捡拾车研发与生产的重要因素。针对圆草捆所处野外环境的多变性、圆草捆本身姿态的多样性,结合满足成功捡拾与提高捡拾效率的预定要求,对提升臂进行了结构预设计,并在此基础上进行优化分析与求解。结果显示;圆草捆捡拾车提升臂的结构设计中,提升臂的离地高度、两臂之间距离、单臂前端斜梁弯折角度及提升臂与车架距离等是影响圆草捆捡拾成功率与捡拾效率的重要参数。为了进一步确定合理的结构参数,对圆草捆捡拾臂进行了结构的理想化建模,并列出了相应优化问题的数学模型,并运用Mat Lab绘出相关图形,结合图解法得出的相关数据,为提升臂结构的设计提供了理论指导。     

缺水地区农用水权置换实践比较与优化研究

农用水权置换制度在我国缺水地区不同程度开展,选择了较为典型的宁夏、内蒙古、甘肃和青海等4个地区,对其农用水权置换实践情况,从缺水地区制度安排、农用水权置换现状、促进经济发展等方面进行了分析,比较其实践情况,发现其在农用水权置换的基础工作、促进地区经济发展等4个方面存在共性以及在农用水权置换发展阶段、选择路径、农户参与程度等3个方面存在差异,最后从政府间区域水权转让、区域水权水量控制和用水户定额管理、农户间水量动态平衡、设定置入方进入门槛和置入方节水指标换取农业水权量等4个层次构建缺水地区农用水权置换体系。     

双作用多级液压缸优化设计探讨

双作用多级液压缸具有运行行程长、设置距离短等优点,在起重机械、运输车辆、工程机械等领域应用广泛,而传统双作用多级液压缸在实际应用中暴露出一些问题,为了确保双作用多级液压缸良好的使用性能,应做好优化设计,完善双作用多级液压缸结构设计。文章分析了传统双作业多级液压缸存在的问题,阐述了双作业多级液压缸的优化设计内容,以供参考。     

基于大系统分解-动态规划聚合法的多块滩涂围垦进度决策优化

为了解决多块滩涂围垦进度决策问题,采用大系统分解-动态规划聚合法对多块滩涂的土地利用进行优化和最优开发。将多块滩涂框围进度最优决策模型分解为若干个单块滩涂土地利用规划线性子模型,采用动态规划逐次逼近法对子系统进行优化,确定各块滩涂在不同投资现值下的多阶段一系列优化结果与收益及费用指标体系,再针对各块滩涂围垦决策子模型采用动态规划法进行动态规划聚合,对多块滩涂进行围垦进度决策。求解方法能够给出多块滩涂框围进度和相应土地利用最优布局和开发进度决策。     

基于GIS技术的渠道工程材料采购模型

为了全面优化企业的采购成本,实现集约化的采购目标,从运输路径规划的角度出发,融合运筹学的知识,创建了基于GIS技术的渠道工程材料采购模型.以材料供应点和仓储点确立为基础,利用GIS软件进行运输路径的选择,进而构建出材料采购的路网模型.通过运用图论领域中的Floyd算法,计算得到材料供需点的最短运输路径,确定出材料的运输费用,结合出厂价格确定材料综合单价.在此基础之上,引入线性规划工具,以最小采购费用作为目标函数、材料综合单价为价值系数、供需平衡条件作为约束条件、供需点之间的采购量作为自变量,建立起采购决策的线性规划模型,并利用Matlab软件和VOGEL方法进行求解对比.实践证明,Matlab软件降低采购费用53万元,VOGEL方法降低34万元,前者确定的采购方案更受青睐.研究表明,基于GIS的采购模型解决了渠道材料采购运距不确定、采购成本虚高问题,为科学合理安排采购方案提供了辅助工具.     

模拟退火粒子群优化投影寻踪的渠道防渗模式评价

为了对渠道防渗工程的方案进行优选,采用模拟退火粒子群优化投影寻踪方法对渠道防渗模式进行优化评价.优化粒子群算法,使其在退火过程中接受优解,且还以一定的概率接受差解.同时利用模拟退火粒子群算法在搜索过程中具有概率突跳的能力,有效地避免搜索过程陷入局部极小解,提高了算法的收敛速度和精度.将该模拟退火粒子群算法与投影寻踪结合,建立了模拟退火粒子群优化投影寻踪模型,将该模型应用到灌区渠道防渗模式优化评价中,选取10个指标作为评判因子,提出适合该地区的干渠渠道防渗工程优化模式,其优劣排序依次为方案Ⅳ、方案Ⅱ、方案Ⅲ、方案Ⅴ、方案Ⅰ.研究表明模拟退火粒子群优化投影寻踪的评价模型对灌区渠道防渗模式进行综合评价是切实可行的,模拟退火粒子群优化投影寻踪的评价方法在解决实际问题中展示了其优越性,并取得了良好的应用效果.     

基于GIS和USLE的龙墩水库小流域土壤侵蚀评估研究

本研究以南京市高淳区龙墩水库流域为研究对象,利用通用土壤流失方程(USLE)模型与地理信息系统(GIS)技术结合的方法对流域土壤侵蚀进行模拟预测。结果表明:整个流域年均土壤侵蚀模数为4 343.46 t/km~2,属中度侵蚀。整个流域微度和轻度侵蚀所占面积比例相对较大,两者所占面积比例之和超过了63%,极强度和剧烈侵蚀虽然所占面积较小,但却产生了超过了70%的侵蚀量。不同土地利用类型中土壤侵蚀强度差异较大,年均侵蚀模数旱田草地水田林地,侵蚀量旱田水田草地林地。通过GIS将整个流域划分为13个子流域,子流域4、5、10由于区域内大部分是旱田,土壤侵蚀模数较大,为流域内土壤侵蚀的关键源区,子流域10侵蚀模数和侵蚀量都比较大,应该重点关注;而子流域1、9和12由于侵蚀总量较大,也应该保持一定的关注。所有子流域土壤侵蚀量都主要来自高强度侵蚀等级,其中以剧烈侵蚀为主。因此,控制土壤侵蚀应该优先考虑高强度侵蚀等级区域。     

Comparing System of Wheat Intensification (SWI) with standard recommended practices in the northwestern plain zone of India

The practices of the System of Rice Intensification (SRI) methodology have been extended to wheat and various other crops with reported good results. To assess such reports with respect to wheat, an experiment was conducted at the Indian Agricultural Research Institute, New Delhi during 2011–2012 and 2012–2013. This experiment compared the performance of wheat under System of Wheat Intensification (SWI) and standard recommended practices (SRPs). In 2011–2012, the SWI yield of 7.93 t ha^?1 was 30% higher than for SRP in 2012–2013, climatically a less favorable year, hence SWI performed relatively better with a 46% yield advantage under climate stress. SWI produced 12.5% less in the stressful year, while the reduction for the SRPs ranged from 18% to 31%. Differences in yield attributes and root traits were also observed in favor of SWI. Available N, P, and K in the soil after harvesting was increased with SWI, whereas depletion in nutrients with the SRPs indicated the scope for SWI sustaining soil fertility. Higher yield compensated for higher SWI costs of cultivation. A net return of US$ 1383 ha^?1 was obtained with SWI, 35% more than the US$ 1020 ha^?1 from SRPs. Overall, SWI outperformed the SRPs in terms of yields, climate resilience, and economics.     

Irrigation,a productive tool for food security – a review

Water scarcity in agriculture is becoming a major problem due to increasing demand from nonagricultural uses and intensive crop management on existing croplands to meet the needs of an expanding global population. Efficient use of the available irrigation water is therefore of important concern. Even though intensive research in the areas of crop physiology, irrigation engineering, agronomy and agricultural economics has developed several ways to improve the efficiency of irrigation water, a multidisciplinary approach is often regarded as the best future path to achieve further enhancements in meeting the forthcoming challenge of producing more and safety foods. Failure of irrigation production has profound effects on the welfare of all those employed in it and also their customers. Indeed, the scale of the industry is such that world food prices will be influenced by the overall performance of the irrigation farmers, but low food prices are essential to the welfare of the poorest people. The contribution of irrigation and water management to increased food production must come through both expansion of irrigation and improved management of existing water supplies. This review presents the past, current and future panorama of irrigation as a viable tool in ensuring food security on the globe. Considering past trends, this review empathizes that future irrigation technologies should be focused on providing the leadership and capacity to capture, develop and promote new irrigation practices and management systems to optimize production.     

多源环状注水系统泵站运行方案与管网同步优化

为了最大程度地提高注水系统运行效率,对泵站运行方案与管网同时进行优化.针对多源环状注水系统,以泵的开停状态、流量和管线的连接状态、管径为优化设计变量,以运行能耗和管网投资费用最小为优化目标,考虑流量、压力、环状管网等各类约束条件,建立了多源环状注水系统运行方案与管网同步优化数学模型.针对该同步优化问题的特点,设计了双重广义染色体编码遗传算法对模型求解.泵的编码中,第1行采用二进制编码表示泵的开停状态,第2行采用实数编码表示泵的流量;管线的编码中,第1行采用二进制编码表示管线的连接状态,第2行采用整数编码表示管线的管径.实现了对各优化变量的精确表达,设计了与问题相适应的初始解产生及编码交叉、变异方法,避免或减少了不可行解的产生.并对实例进行优化设计,同步优化与仅进行管网优化对比,运行能耗降低了4.66%,管网投资费用降低了1.73%,表明同步优化的节能效果明显.