Heuristic approaches for mine planning and production scheduling

Summary Traditional methods and opimization methods for mine planning and production scheduling have failed to provide easy to use tools that yield improved results. Two new approaches, each combining the best of the traditional and the optimization, are described.     

Assessing a farmer's decision concerning the application timing of nitrogen fertilizer

This paper is concerned with a farmer's decision on the timing of nitrogen fertilizer application. Analytical models are developed to determine the necessary conditions for the optimal timing of the application of nitrogen fertilizer. The models, coupled with an estimated cotton yield function, are used to assess a farmer's decision on the optimal application timing of nitrogen fertilizer in cotton production. The empirical results explain various observed application timings of nitrogen fertilizer being used in cotton production in Mississippi, USA, and provide an estimate of the cost to a farmer when he or she must comply with a restriction on the timing of the application of nitrogen fertilizer.The views expressed are those of the authors, and do not necessarily represent the policies of the US Department of Agriculture or the views of other US Department of Agriculture staff members     

Methane Production, Emission and Possible Control Measures in the Rice Agriculture

In the rice field methane is produced in the soil layer with depths of 2-25 cm. The vertical profile of methane production rate in the paddy soil during the water covering period differs from that in the paddy soil in dry phase. Only a small part, about 30%. of the produced methane is emitted to the atmosphere through rice plant, air bubbles, and molecular diffusion. Therefore, the methane emission rate from the rice field depends not only on the methane production rate in the soil, but also on the transport efficiency of the rice plant, air bubble formation that in turn depends on the production rate, and molecular diffusion.Field measurements show that methane emission rates from a particular rice field have very large diurnal, seasonal and interannual variations, which are related to soil characteristics, water regime, farming procedure, local climate, and rice growing activities. The relationship between the methane emission rate and the above mentioned factors is very complicated. The emission rate     

An efficient approach for characterizing basin-scale hydrodynamics

As the upstream oil and gas sector continues to use more groundwater resources for their operations, a comprehensive understanding of formation fluids at the sedimentary basin scale is required to inventory and manage available groundwater resources. Basin-scale fluid flow is often simplified to only assess pre-development groundwater conditions without understanding how large-scale hydrocarbon development might be changing regional flow patterns. This study focuses on two aspects of hydrogeological mapping for characterizing basin-scale hydrodynamics: (1) assessing the influence of hydrocarbon production and injection on pressure measurements used to map hydraulic heads and infer groundwater conditions; and (2) determining the effects of variable density groundwater on understanding the magnitude and direction of flow primarily in saline formation water aquifers. Drillstem Tests (DST's) are transient pressure tests that are used to infer regional groundwater flow, but they can be strongly affected when the sample location is located within the vicinity of a hydrocarbon production or injection well. To identify production and injection influences this study implements a Cumulative Interference Index (CII) methodology. This implementation can be used to map pre-development groundwater flow conditions and evaluate regional changes or effects due to historical oil and gas activity. Density effects are often neglected and can have considerable effect on groundwater flow in cases where aquifers contain dense brines, are inclined and sloping, or possess weaker hydraulic gradients than the buoyancy force potential. This study implements a vectorial analysis to identify flow directions in regions where density driven flow is important and can change the inferred magnitude and direction of flow. Two case studies are presented to demonstrate the effectiveness of these methodologies at evaluating basin-scale hydrodynamics.     

基于熵权TOPSIS法的沿海地区渔业产业融合发展效果评价研究

2019年全国渔业渔政工作重点之一就是“大力推进一二三产业融合发展”。渔业一二三产业融合是实现渔业高质量发展和传统产业升级的重要举措。渔业产业融合发展,就是以渔业为基本依托,有效整合渔业生产、水产品加工、流通与贸易、休闲渔业及其他生产性服务业,以产业链延伸、产业范围拓展和产业功能转型为表征,促进渔业、渔村发展,渔民增收。近年来,我国渔业三产融合发展取得了一些成就,如何来评价渔业三产融合发展带来的效益,值得关注。已有的研究主要从渔业的经济效益或者海洋生态环境可持续发展角度研究,很少有从多个维度对海洋渔业产业融合发展带来的效果进行综合评价,所以文章从渔业生产效率、渔业经济效益、渔业产业链延伸以及绿色可持续发展4个维度设计了渔业一二三产业融合发展效果评价指标体系,并对沿海10个地区的融合发展效果进行评价研究。研究结论：(1)基于空间视角,山东、广东的渔业三产融合发展水平较高,浙江、江苏、福建紧随其后。(2)基于产业结构视角,各地区在渔业融合发展过程中存在不同程度的发展不均衡问题,在评价体系中,渔业绿色可持续发展水平较其他指标呈现较低情况。(3)基于时间序列视角,渔业产业融合发展整体水平呈现上...     

全球生产网络视角下珠三角区域经济的战略耦合与产业升级

借助全球生产网络(GPN)理论的视角,审视了以珠三角为代表的后发地区产业发展与升级的路径。通过阐述GPN框架的理论优势和分析逻辑,明晰了战略耦合概念的4种一般机制,继而以珠三角产业发展和升级历程为例,说明了战略耦合模式如何影响区域产业经济发展的路径,当前战略耦合演变的方式和原因,及其所带来的影响。文章认为珠三角当前基本已经走出"前店后厂"模式,产业发展的格局已经发生本质性的改变,其主要原因是战略耦合的方式发生了改变,从而导致了多样化的产业升级路径和成果。文章的贡献在于提供了一个更为平衡的视角,来解析以珠三角为代表的落后地区的产业升级的动态,揭示了后发地区的产业升级是一个多尺度、多路径的过程。     

Flounder growth and production as indicators of the nursery value of marsh habitats in a Mediterranean lagoon

Estuarine marshes are known as suitable nursery areas for many marine migrant fishes, such as flounder. The potential nursery value of such habitats was investigated in the Venice lagoon, by using growth and production of 0-group flounder as indicators. Size–frequency distribution analysis was performed on fish samples collected fortnightly, from March 2004 to June 2005, in two marsh sites, Dese and Tessera, differing in their origin and environmental conditions. Samples were mostly composed of juvenile individuals, belonging to 0- and 1-group cohorts (the latter being present in Tessera only). A higher total production, either annual or monthly, and faster growth of 0-group flounder was observed in Dese, associated to a higher ecological performance of 0-group individuals in this site, as indicated by the higher P:B ratio values. Dese is a site located in a marsh complex characterized by the relevant influence of a nearby river, and the observed higher potential nursery value of this marsh area with respect to the other is discussed in the light of the higher trophic status and other environmental conditions in this site. The production results were also compared to those from other estuarine environments commonly acknowledged as important nurseries for European flounder.     

怒江州产业结构调整的生产要素分析

通过对怒江州产业结构调整的优势和劣势生产要素分析,依据市场前景广阔、产业关联度大、带动性强、经济效益好、能够支撑和带动本行业快速发展的主导产业选择原则,提出围绕矿产、水电和旅游3大资源进行扶贫-发展,立足怒江水电开发,以兰坪铅锌矿为重点的矿业开发,以民族文化、旅游景点和旅游环线为重点的旅游开发,以畜牧业和绿色产业为重点的现代农业发展作为主攻方向,推进怒江州产业结构的全面优化升级。     

珠江三角洲镇域乡镇工业生产组织与发展研究──以民乐、人和、北三镇为例

乡镇工业迅速增长是改革开放以来珠江三角洲区域经济发展的重要特征和区域城市化的主要动力。借鉴西方工业生产组织理论,从镇域这一基本空间单位出发,以民乐、人和、北三镇为例,探讨了乡镇工业企业生产的组织及其变化对镇域地方工业发展所产生的影响。认为在有关外部条件的作用下,企业本身的运作是影响珠江三角洲区域内乡镇工业发展的根本因素。在此基础上就镇级地方政府如何科学引导镇域地方乡镇工业的发展提出了建议     

海水制盐的气象条件分析

通过对广西防城港市企沙盐场1996~2005年近10年的原盐产量与气象条件的关系进行分析,得出影响海水制盐的主要气象因子是降水、蒸发量、气温、大风,并提出各种气象条件下的生产对策及气象部门对盐业服务的思路和设想。