金川矿井通风网络自动简化数学模型与简化技术

重点论述了矿井通风网络自动简化数学模型以及简化技术 ;用网络简化程序框图及网络简化过程、结果、层次图 ,介绍了网络简化程序 ;给出了应用这一自动简化技术的实例     

An effective technique for wastewater minimisation in batch processes

This paper presents a mathematical formulation for freshwater and wastewater minimisation in multipurpose batch plants. The minimisation of wastewater is achieved through the exploitation of recycle and reuse opportunities. A superstructure that entails all possible recycle and reuse possibilities is used as the basis for the formulation. The existence of an optimal production schedule, which provides starting and finishing times for water using operations, is assumed. The paper addresses the specific case where the contaminant concentration in the outlet water stream from each operation is maintained at its maximum. This condition allows the overall model to be cast as a mixed integer linear programming (MILP) problem for which global optimality is guaranteed. The effectiveness of the developed formulation is demonstrated through a published literature example and a practical case study.     

泥石流危险区划中相对分布密度的数学模型

本文通过数理统计分析,建立了泥石流相对分布密度的数学模型,解决了泥石流危险区划中关键指标的确定问题,在云南和四川泥石流危险区划的应用中效果良好,是一项行之有效的方法。     

Simulation of Rabies Epizootic Process in Fox Populations at a Limited Carrying Capacity of Biotopes

To describe the epizootic process of rabies in fox populations, a model based on a cellular automata network (Toffoli and Margolus, 1991) was constructed. The cell state and the rules of transition from one state to another were determined in accordance with a modification of the previous model based on a differential equation system, which was proposed to describe the epizootics of fox rabies in Western Europe. The new model provides the possibility of simulating spatial heterogeneity and indices of animal mobility related, in particular, to the seasonal features of fox ecology. Calculations were made using population parameters characteristic of biotopes with a low carrying capacity (the steppe zone of Western Siberia). According to the model, the maintenance of rabies epizootics in these biotopes is possible on condition that the mobility of foxes in them is much higher than in the biotopes with a high carrying capacity. This model can be used for prognosis and epidemiological control in natural rabies foci.     

生物质燃烧过程颗粒模型现状分析

生物质颗粒燃烧过程计算是生物质能利用、火灾过程分析及城市固体垃圾焚烧技术开发的基础。其计算结果的准确度取决于对所研究物理问题的数学模型是否正确。总结了生物质颗粒燃烧涉及的模型。对比了反应区域模型中面反应模型和体积反应模型,指出面反应模型适合计算传输控制过程,而体积反应模型适合计算动力控制或动力传输共同控制的过程。总结了干燥、热解、炭氧化等物理化学变化以及动量、热量和质量传递主要方程及方程中涉及的参数。结果表明,这些方程和参数差异显著,仍需实验研究辅助模型选取。     

城市地震灾害风险评价的数学模型

本文用模糊集方法建立了城市地震灾害风险评价的数学模型，是文献［１，２］所述风险模型在地震灾害分析中的具体应用。本文详细介绍了如何确定模糊超越率μｚ（ｙ，ｘ）的途径，并提供了计算承灾体灾害程度可能性分布ＰＯＳＳ（ｌ，ｙ）的方法。     

Scenarios of global bioenergy production: The trade-offs between agricultural expansion, intensification and trade

Increased future demands for food, fibre and fuels from biomass can only be met if the available land and water resources on a global scale are used and managed as efficiently as possible. The main routes for making the global agricultural system more productive are through intensification and technological change on currently used agricultural land, land expansion into currently non-agricultural areas, and international trade in agricultural commodities and processed goods. In order to analyse the trade-offs and synergies between these options, we present a global bio-economic modelling approach with a special focus on spatially explicit land and water constraints as well as technological change in agricultural production. For a global bioenergy demand scenario reaching 100 ExaJoule (EJ) until 2055 we derive a required rate of productivity increase on agricultural land between 1.2 and 1.4 percent per year under different land allocation options. A very high pressure for yield increase occurs in Sub-Saharan Africa and the Middle East, even without additional bioenergy demand. Moreover, we analyse the implicit values (shadow prices) of limited water resources. The shadow prices for bioenergy are provided as a metric for assessing the trade-offs between different land allocation options and as a link between the agricultural and energy sector.     

Multi‐phase non‐steady state equilibrium model for evaluation of environmental fate of organic chemicals

A simple mathematical fate model, Multi‐Phase Non‐Steady State Equilibrium Model (MNSEM) is proposed to evaluate distribution, persistence, and concentrations of chemicals in a model environment consisting of air, water, soil and sediment phases. The model is applied to evaluation of environmental fate and concentration of trichloroethylene and 1,4‐dichlorobenzene under generic conditions representative of Japan.

Evaluated chemical concentrations in air are within a factor of 3 of average values in Japanese atmosphere, and evaluated concentrations in water, sediment, or fish are greater than an order of magnitude below detection limits in real environments, so that evaluated concentrations are in reasonable agreement with environmental measurement data in Japan.

Although MNSEM is not a model for site‐specific evaluation of environmental fate, results suggested that this model is an adequate method to aid in evaluation of fate of chemicals under generic environment conditions. Evaluated concentration‐profiles may be used to estimate average chemical exposure concentrations for humans and the environment.