Study on Mechanism of the Reinforcing Effect of Geogrid in Soil Dam

An experimental study on consolidation and drainage of two gravels with different grading was carried out using high - pressure large - scale tri - axial testing facility. A concept of equivalent surrounding pressure is introduced. An analysis was carried out on the effect and mechanism of reinforcement, experimental surrounding pressure and soil properties. Results show that the reinforcement can improve the strength and failure strain of the material and delay the failure of the soil. The effect of reinforcement of soil - gravel depends on the surrounding pressure and weathering of the gravel.     

Simulation of High Pressure Startu Poil Pum Pof Turbine

Dynamic mathematical model, which is based on the character of the 200 MW tubine lbricating oil system, is established by means of modularization. On the basis of dynamic mathematical models, simulation model of the startu Pprocess of hign pressure startu Poil pum Pis created with the Visual Fortran language. The validity of this model has been verified by the simulation experiments and analysis. The simulation helps to forecast the dynamic characteristic to high pressure startu Poil pum Pand have some directive significance to design method of lubricating oil system.     

地下滴灌灌水器出口正压试验研究

通过试验 ,研究了灌水器类型、流量、工作压力和土壤初始含水量对地下滴灌灌水器出口正压的影响规律。结果表明 :灌水器埋入土壤后 ,其出流由于受土壤等因素的限制 ,在灌水器出口处产生了一定的正压 ,该正压随着灌水历时的延长而增大。影响地埋灌水器出口正压的主要因素是灌水器的额定流量和土壤初始含水量     

喷油泵回油压力对油耗测试精度的影响及解决方法

为提高发动机的油耗测试精度，对影响油耗测试精度的主要原因及其解决方法进行了分析研究和试验。试验表明：柱塞式喷油泵的回油压力是影响测试精度的主要原因，用软件消除回油压力信号和用消波器消除回油压力波，是消除回油压力影响、提高油耗测试精度最简便可靠的方法。     

柴油机电控高压共轨喷油系统的应用

燃油喷射系统作为柴油机的“心脏”,其性能好坏直接影响柴油机的性能和工作可靠性。随着人们对柴油机智能化、强度化、经济性和排放性的要求越来越高,燃油喷射系统的研究也越来越受到重视。未来柴油机必须满足更严格的排放法规,而高压共轨系统具有高度的控制灵活性,其已成为降低柴油机排放的主要核心技术之一。为此,介绍了这种喷油系统的构成、工作原理、特点和现状。     

连续可变相位配气机构的设计

设计了一种机械-液压混合控制式相位连续可变配气机构,以一个旋转阀代替了原有的凸轮轴,用液压力开启气门,以内燃机的转速控制旋转阀的位置,从而达到控制配气相位的目的。     

软硬物质分离技术及其关键设备的研究

根据农副产品加工技术的现状以及现有典型设备的适用范围和特点,介绍了农副产品软硬物质分离机的结构和工作原理.该机解决了现有同类设备加工品种单一的问题,可以用在农副产品、水产品加工领域,具有分离效果好、含杂质率低、产品产出率高和结构独特等特点.     

Modernization of furrow irrigation in the South-East of France automation at field level and its implications

Surface irrigation rehabilitation in the South-East of France has shown success ever since the beginning of its development in the early 1980s. The gradual introduction of surface distributors, mechanized or automated has resulted in water savings and above all in decreased labor input. The distributors used are: gated pipes, layflat tubing, buried low pressure pipe and cablegation. They are used over an ever increasing area which attained about 1000 ha in 1987.Improvement is made in furrow head distribution as well as in field levelling, furrow flow evaluation, flow control at the head of the furrow and in the collective system.The effect of a modernized system and improved knowledge has been to make automated surface irrigation (particularly furrow irrigation) a modern application method in competition with techniques such as sprinklers and localized irrigation.Abbreviations ASAE American Society of Agricultural Engineers - CEMAGREF Centre d'Etude du Machinisme Agricole du Génie Rural des Eaux et des Forêts, Division Irrigation, BP 5095, 34033 Montpellier et BP 31 Le Tholonet 13612 AIX - ENGREF Ecole Nationale du Génie Rural des Eaux et des Forêts, Département Maîtrise de l'Eau et Développement, BP 5093, 34033 Montpellier - IRAT Institute de Recherche en Agronomie Tropicale, Zolad Mini Parc Bt7, 34100 Montpellier - P.V.C. Polyvinyl chloride - RNEDHA Réseau National Expérimentation Démonstration secteur Hydraulique Agricole, BP 5095, 34033 Montpellier - SCP Société du Canal de Provence et d'Aménagement de la Région Provençale, BP 100, 13603 AIX en Provence     

Farmers' irrigation practices in a high rainfall area

Recent droughts in the humid southeastern United States have focused attention on the need for and use of supplemental irrigation. Total annual rainfall amounts are sufficient for most crops in the region. However, erratic distribution of rainfall and the low water-holding capacities of most soils in the region cause frequent drought stresses in many crops. An on-farm study was conducted in southeastern Alabama to evaluate the effects of farmers' irrigation scheduling decisions on soil moisture variations in peanut fields irrigated with center-pivot irrigation systems. The study showed that the way irrigation was practiced in this high rainfall area often caused soil moisture deficit (SMD) level higher than the desired SMD limit during over 20% of the 140-day growing season. This is partially due to farmers' tendency to delay irrigation in anticipation of rainfall which may or may not occur, as rainfall during the growing season is often erratic and local. In contrast SMD in non-irrigated fields was higher than the SMD limit for half of the growing season.Abbreviations SMD soil moisture deficit - ET evapotranspiration - R_eff effective rainfall - WHC water holding capacity