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61.
Javid Jouzdani Seyed Jafar Sadjadi Mohammad Fathian 《Applied Mathematical Modelling》2013,37(18-19):8467-8483
In this paper, dynamic dairy facility location and supply chain planning are studied through minimizing the costs of facility location, traffic congestion and transportation of raw/processed milk and dairy products under demand uncertainty. The proposed model dynamically incorporates possible changes in transportation network, facility investment costs, monetary value of time and changes in production process. In addition, the time variation and the demand uncertainty for dairy products in each period of the planning horizon is taken into account to determine the optimal facility location and the optimal production volumes. Computational results are presented for the model on a number of test problems. Also, an empirical case study is conducted in order to investigate the dynamic effects of traffic congestion and demand uncertainty on facility location design and total system costs. 相似文献
62.
This paper considers an aging multi‐state system, where the system failure rate varies with time. After any failure, maintenance is performed by an external repair team. Repair rate and cost of each repair are determined by a corresponding corrective maintenance contract with a repair team. The service market can provide different kinds of maintenance contracts to the system owner, which also can be changed after each specified time period. The owner of the system would like to determine a series of repair contracts during the system life cycle in order to minimize the total expected cost while satisfying the system availability. Operating cost, repair cost and penalty cost for system failures should be taken into account. The paper proposes a method for determining such optimal series of maintenance contracts. The method is based on the piecewise constant approximation for an increasing failure rate function in order to assess lower and upper bounds of the total expected cost and system availability by using Markov models. The genetic algorithm is used as the optimization technique. Numerical example is presented to illustrate the approach. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
63.
以国家重大区域规划中的长三角为实证研究对象,利用加权灰色关联度筛选出与政策效果评价关联性高度相关的政策指标:中央财政专项拨款、中央补助收入、中央固定资产投资额,进而建立政策指标与规划目标的第三产业增加值的对数回归函数,通过过去的数据预测某一特定年份第三产业增加值,并与该年份的实际值进行对比、评价国家重大区域规划的政策效果。本文的特色与创新一是通过灰色关联度剔除与政策效果评价关联度小的指标,筛选出对重大区域规划政策效果有显著影响的关键因素。二是通过时间权向量对政策指标的关联度进行加权,体现时间越近的年份、加权灰色关联度越大,指标越应该保留的思路,保证年份越近的指标数据、对评价结果影响越显著。三是通过历史数据的预测,得到在没有规划政策下、区域自然发展的目标效果,并把其与同一时点、政策实施后的实际效果进行对比,得到政策实施后的政策绩效。实证结果表明应该增大对上海和浙江影响显著的中央财政专项拨款的政策投入,减少对上海和浙江影响不显著的中央固定资产投资额的投入。 相似文献
64.
控规数据向ArcGIS平台数据转换并入库是城市规划管理信息系统(UPMIS)建设的一项基础性工作.针对分析控规数据转换为ArcGIS平台数据存在的问题,提出了一种高效的控规数据向ArcGIS平台数据批量转换的方法,并结合ArcGIS VBA和Python脚本开发工具,实现了上述方法.测试实验表明,该方法自动化程度高、实现简单、处理效率高. 相似文献
65.
推进新型城镇化是新时期的重要战略任务,是各城镇走向健康、可持续发展的主要路径之一.为此,以慈溪市观海卫镇为例,通过实地调研和问题思考,分析工业型城镇的空间发展历程及特征,指出其存在以外延扩张式发展为主导、开发模式亟待转变、用地布局杂乱、缺乏有序引导、公建设施与公共空间不足等问题.新型城镇化战略下,工业型城镇应加快城镇产业转型和城乡产业协同发展,促进城镇发展动力多元化;转变城镇发展模式,注重城镇内涵式发展;以人为本,提高城镇品质,建设现代化城镇. 相似文献
66.
A combination of "black box" and "calendar-time" methods for the determination of calibration intervals of an analytical
measuring instrument is discussed. Since the methods require information on the distributions of the calibration parameters,
such information is described for an atomic absorption spectrophotometer, as an example. The hypotheses on the normal distribution
of the calibration parameters are tested using the ω2-criterion and accepted at 0.90–0.95 levels of confidence. Corresponding control charts are designed for indication of warning
and action limits of the calibration parameters, and diagnoses of outliers in further calibrations. Control charts indicate
also when the calibration should be done according to the full program of the equipment manufacturer.
Received: 15 April 2000 / Accepted: 24 July 2000 相似文献
67.
Toshitaka Gamo 《Trends in analytical chemistry : TRAC》2011,30(8):1308-1319
The Sea of Japan, a semi-closed marginal sea (greatest depth ∼3700 m) in the northwestern-most Pacific Ocean, has an independent, deep convection system, which is driven by the formation and the sinking of cool, saline surface water towards the bottom in severe winters. Continuous measurement of dissolved oxygen using highly precise versions of the Winkler titration method has revealed 8-10% decreases in the bottom concentration of oxygen (O2) over the past 30 years. The temporal decrease in O2 means an imbalance between the supply of O2 from the surface and the in situ consumption of O2 in decomposing organic matter, suggesting that the change in the deep convection pattern of the Sea of Japan is probably caused by global climate change to reduce winter cooling of surface seawater. 相似文献
68.
Synthesis,characterization and catalytic performance of nanosized iron-cobalt catalysts for light olefins production 下载免费PDF全文
Nanosized Fe-Co catalysts were prepared by co-precipitation method and studied for the conversion of synthesis gas to light olefins.In particular,the effects of a range of preparation variables such as Co/Fe molar ratios of the precipitation solution,pH value of precipitate,temperature of precipitation,promoters and loading of optimum promoter on the structure and catalytic performance are investigated.The optimal nano catalyst for light olefins (C2-C4) production was obtained over the catalyst with Co/Fe molar ratio of 3/1 which promoted with 2 wt% K.The results show that the best operational conditions were GHSV=2200 h-1 (H2/CO=2/1) at 260℃ under atmospheric pressure.Characterization of catalysts were carried out using X-ray diffraction (XRD),thermal gravimetric analysis (TGA),differential scanning calorimetry (DSC),scanning electron microscopy (SEM),transmission electron microscopy (TEM) and N2 physisorption measurements such as Brunauer-Emmett-Teller (BET) and Barrett-Joyner-Halenda (BJH) methods. 相似文献
69.
Paul G. Mezey 《Theoretical chemistry accounts》1985,67(1):43-61
The family of all possible reaction mechanisms on a potential surface has an algebraic structure with potential applications in quantum chemical molecular design and synthesis planning.Transformation properties and equivalence relations of reaction paths on potential energy hypersurfaces lead to a topological definition of reaction mechanisms. The family of all fundamental reaction mechanisms on the hypersurface has a group structure,the fundamental group of an appropriately defined topological space. Isomorphism and homomorphism relations between fundamental groups of reaction mechanisms are used to characterize the chemically important topological properties of various subsets of a hypersurface, or those of different excited state hypersurfaces. 相似文献
70.
The capacity for anaerobic decolorization of a sulfonated azo dye, Congo Red, by a strain of a sulfate-reducing bacterium
was evaluated. After optimizing the growth rate of the bacteria on a simple carbon source and terminal electron acceptor pair,
lactate and sulfate, respectively, the effect of the dye concentration on their growth rate was analyzed. The decolorization
rate was affected by the dye concentration in the growth medium. The azo-bond cleavage mechanism of reductive decolorization
with the formation of benzidine was consistent with the results, as this metabolite was identified by high-performance liquid
chromatography. Several fractions of the culture medium, including lysed cell extracts, were examined for the capacity to
reduce the azo dye. This reduction capacity was found in the culture medium in which the cells had previously grown. The results
showed that the mechanism of reductive decolorization of this sulfonated azo dye was extracellular and nonenzymatic, consistent
with the production of sulfide anion by the microorganisms while growing on lactate and sulfate. The sulfide anions were the
cause of the reduction leading to the disappearance of color in the medium. To increase the rate of decolorization, the presence
of ferrous ion was also necessary together with the lactate and sulfate substrates. 相似文献