搜索结果: 1-8 共查到“农业工程 Models”相关记录8条 . 查询时间(0.159 秒)
湍流模型在双吸离心泵数值模拟中的适用性分析（Applicability of Turbulence Models in Numerical Simulation of Double Suction Centrifugal Pump）
离心泵 湍流模型 CFD 数值模拟
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2010/12/28
以双吸离心泵为研究对象，在Fluent软件中采用标准k-ε模型、RNG k-ε模型、Realizable k-ε模型和雷诺应力模型4种湍流模型在相同网格条件下进行三维、稳态数值模拟，计算其在不同工况下的扬程及水力效率；然后以RNG k-ε模型计算结果作为初值，用大涡模拟方法进行三维、非稳态数值模拟，计算叶轮旋转一周的平均扬程及平均水力效率，与真机数据进行对比分析。计算结果表明：Fluent软件在...
Applicability of models based on deterministic chaos theory for forecasting of electricity sales in rural areas
electric energy forecast deterministic chaos
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2014/2/26
The applicability of models based on deterministic chaos theory, in particular the self-similar fractal models, logistic models according to Prigogine, logistic models according to Schuster, and heuri...
变量穴施水穴播机的变量施水数学模型（Mathematic Models of Water Application for a Variable Rate Irrigating Hill-seeder）
穴施水穴播机 变量施水 数学模型
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2009/11/3
根据变量穴施水穴播机使用要求，建立了最小施水量数学模型和电磁阀控制时间数学模型。在自行开发的变量穴施水穴播机上进行静态试验，通过改变水箱水量、施水时间，获得不同的施水量。分别采用回归分析和人工神经网络预测2种方法，研究了水箱水量、施水时间及施水量之间的关系，建立了电磁阀控制时间的数学模型。回归试验表明，在水箱水量处于满箱、半箱和1/8箱容积3种状态时，所对应的电磁阀控制时间线性回归模型的调整判定系...
Simulation of Drought Periods Using Stochastic Models
Rainfall Hydrologically homogeneous region ARIMA model Drought period
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2009/10/12
This paper presents a methodology for the modeling of the agricultural drought duration in the Tokat region. For this purpose, the study area was divided into 4 hydrologically homogeneous regions. A r...
Daily River Flow Forecasting Using Artificial Neural Networks and Auto-Regressive Models
Streamflow forecasting Neural networks Auto-regressive models
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2009/10/10
Estimating the flows of rivers can have a signi cant economic impact, as this can help in agricultural water management and in providing protection from water shortages and possible flood damage. This...
温室环境控制与温室模拟模型研究现状分析（Review on Environmental Control and Simulation Models for Greenhouses）
环境控制 温室 模拟 数学模型
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2009/8/11
综述了温室环境控制系统、控制策略及环境模拟等研究领域的发展状况。目前温室环境主要采用多处理器的分布式控制系统，控制器以结构通用、价格便宜的单片机为主，也可应用工业控制器，但工业控制器的价格较高。环境控制的研究重点是控制系统的智能化和信号传输的无线化，无线传输适合温室特点，为现场布线及后期维护带来方便。通过模拟模型可以了解结构特征、气象条件及作物生长等对温室环境的影响。综合考虑环境因子、作物生长及经...
Comparison of Erosion and Runoff Predicted by WEPP and AGNPS Models Using a Geographic Information System
Modeling WEPP AGNPS Surface runoff Soil erosion
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2009/1/13
The Water Erosion Prediction Project (WEPP) model and the Agricultural Non-Point-Source Pollution Model (AGNPS) were used in conjunction with a geographic information system (GIS) database to predict ...
Formalised risk identification and evaluation models application in the conditions of agricultural enterprises
business management instruments planning and decision making process control risk evaluation risk factors critical point analysis, controlling, internal audit
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2014/3/26
Recently we can mention in the CR a step by step enterprise number increase in the area of production, transport services, services and financial organisations, which practically apply internal depart...