Automatic milking systems, farm size, and milk production

Automatic milking systems (AMS) offer relief from the demanding routine of milking. Although many AMS are in use in Europe and a few are used in the United States, the potential benefit for American farms is uncertain. A farm-simulation model was used to determine the long-term, whole-farm effect of implementing AMS on farm sizes of 30 to 270 cows. Highest farm net return to management and unpaid factors was when AMS were used at maximal milking capacity. Adding stalls to increase milking frequency and possibly increase production generally did not improve net return. Compared with new traditional milking systems, the greatest potential economic benefit was a single-stall AMS on a farm size of 60 cows at a moderate milk production level (8600 kg/cow). On other farm sizes using single-stall type robotic units, losses in annual net return of 0 dollars to 300 dollars/cow were projected, with the greatest losses on larger farms and at high milk production (10,900 kg/cow). Systems with one robot serving multiple stalls provided a greater net return than single-stall systems, and this net return was competitive with traditional parlors for 50- to 130-cow farm sizes. The potential benefit of AMS was improved by 100 dollars/cow per year if the AMS increased production an additional 5%. A 20% reduction in initial equipment cost or doubling milking labor cost also improved annual net return of an AMS by up to 100 dollars/cow. Annual net return was reduced by 110 dollars/cow, though, if the economic life of the AMS was reduced by 3 yr for a more rapid depreciation than that normally used with traditional milking systems. Thus, under current assumptions, the economic return for an AMS was similar to that of new parlor systems on smaller farms when the milking capacity of the AMS was well matched to herd size and milk production level.     

桂林旅游珠宝市场中信息不对称现象的透视及管理对策

针对目前桂林市珠宝工艺品市场中存在诸多问题，试用经济学中的信息不对称理论，并结合博奕原理，分析了目前桂林市珠宝工艺品市场中存在的种种不良现象，提出减少信息不对称程度，必然有助于维护旅游者的权益，这为有效管理桂林旅游工艺品市场提供了思路。     

燃气电厂调压站管壳式换热器的比较与分析

目前用于燃气电厂调压站的换热器主要有国产单管式及进口双管式两种型式,文章主要从安全性和经济性两方面对这两种换热器进行比较、分析。     

对迎接知识经济时代到来的思考

知识经济是当前人们讨论的热门话题之一。对知识经济时代到来及由此产生的深刻变化应有充分的准备。作者就知识经济的意义及如何发展知识表明几点看法。     

坚持管理与科技两个轮子齐驱动

大乘资氮集团有限公司狠抓管理和科技，使企业由经营型向效益型转变，同时加速了企业经济增长方式的转变。     

BASIC ECONOMIC OPTIMIZATION MODEL FOR A CONTINUOUS EXTRACTION PROCESS*

A basic mathematical model, mainly focused on economic assessment is directly applied to a counter-current, stage-wise, solvent-selective extraction system. A standard extraction model, based on the modeling of a mixer-settler process, is used as point of departure. This system is used to extract a dissolved compound in a process stream. Thereafter sensible operating and economic parameters are integrated into it. An adequate handling of these parameters allows a practical preliminary optimization process modeling. The economic assessment model can be applied from one to ri stages in any industrial stage-wise process unit. An optimum number of stages are determined based on solvent extraction and economic assessment.     

卫生经济学应用于慢性病防控决策的战略研究

为提高当前慢性病防控体系的效率,更好地遏制慢性病的流行,保护公众健康,2015年中国工程院设立了\"卫生经济学应用于慢性病防控决策的战略研究\"重大咨询项目。课题组调研发现,作为一种重要的卫生决策工具,卫生经济学在慢性病防控决策过程中尚处于初级应用阶段。对卫生经济学的重要性认识不足,对卫生经济学的方法的掌握和应用能力有限,制约了其在慢性病防控决策中的应用,因此建议建立多元主体参与的卫生经济学研究力量,加强卫生经济学应用于慢性病防控决策的大数据积累及应用研究,提出将卫生经济学应用于我国慢性病防控决策的战略框架。     

当前储能市场和储能经济性分析

储能在未来电网以及可再生能源的应用中将起到至关重要的作用.它的应用范围涉及发电、传输、分配乃至终端用户.本文简要分析并总结了储能市场的经济性,重点阐述了储能应用的主要瓶颈问题——成本.通过分析与计算,确定了储能产品的目标成本,并且以材料创新及以历史上光伏产业规模效应的经验曲线为参考分析了能够降低储能成本的可行途径.储能应用市场将为传统能源结构带来根本性的变化,给社会经济带来巨大的福利,它的应用势在必行.但是,要实现储能的大规模应用还有诸多艰巨的任务与挑战,其中最重要的是要降低储能系统的成本,而实现这个目标需要多方面的共同努力.     

On the tuning of predictive controllers: Impact of disturbances,constraints, and feedback structure

The impact of problem formulation modifications on predictive controller tuning is investigated. First, the proposed tuning method is shown to adapt to disturbance characteristic changes and thus, takes full economic advantage of the scenario. The second topic concerns point‐wise‐in‐time constraints and the impact of constraint infeasibility. Specifically, we shift the tuning question from selection of nonintuitive weighting matrix parameters to that of a few key parameters and results in a rather intuitive trade‐off between expected profit and expected constraint violations. Finally, we show that simple modifications will allow for the consideration of various feedback structures, including computational delay and partial state information. The overall conclusions of the work are that the results of the automated algorithm will help build an intuitive understating of the dynamics of the process and ultimately result in a higher level trade‐off between profit and constraint observance. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3473–3489, 2014     

合成氨装置低负荷经济性与稳定性探讨

探讨合成氨装置低负荷运行中存在的主要问题,分析影响其经济性和稳定性的因素．提出了消除低负荷运行瓶颈的见解,进一步优化装置低负荷运行工况,确保长周期经济运行。