筛式砂土石分离施肥机的结构设计

在宁夏贺兰山东麓葡萄种植基地,由于当地的土层砂石比较多,并且有的块径特别大,影响葡萄的种植、生长和培育。为了实现对砂土石的自动分离以及葡萄沟挖掘过程中底肥的自动施加,针对当地的土质特点,结合人工对砂土石分离和底肥施加的操作过程,文中设计了一套筛式砂土石分离施肥一体机。它的主要功能有两个,一是实现砂土和石头的分离,二是实现分离后的砂土与底肥混合均匀。

葡萄种植中土石分离混料机的设计——基于TRIZ理论

针对宁夏贺兰山东麓葡萄种植基地,葡萄种植定值沟的挖掘作业步骤繁琐、耗费时间长,劳动强度大、工作效率低等现状,基于TRIZ理论并运用技术矛盾冲突设计了土石分离混料机。该机是集土石分离、土壤与农家肥混合并回填定植沟等作业同步进行的机械设备,彻底改变了人工捡石、施肥、旋耕、机械挖掘等传统的作业模式,大大节省了人力、物力,并提高了葡萄种植定植沟挖掘作业的工作效率。

1JS-100土壤捡石机的设计

目前,宜机化整治后大量岩石留在地表和耕作层,严重影响农业生产,迫切需要一种效率高、不仅能捡拾地表岩石还可搜索土层的机具来解决这一难题。为此,通过对国内外研究现状与发展趋势进行分析,设计了挖掘式土壤捡石机,并进行了挖掘机构、土石分离装置、集石装置理论计算及样机试制。田间试验结果表明:土壤捡石机纯工作时间作业效率为0.135hm^(2)/h,平均石块捡净率95.4%,石块含土率9.9%,基本达到样机设计要求,但需要进一步试验,以验证其稳定性和对不同土壤的适应性。

国外土壤捡石机工作原理及特点分析

土壤捡石机在我国尚未得到推广,相比农机发达国家,我国对该机种的研究还处于起步阶段,因此学习国外先进技术是当务之急。就几种国外先进机型的工作原理及特点进行分析,以便在研制开发过程中取长补短,少走弯路。

复垦农田链式捡石机的设计与试验

针对现有链式捡石机存在的捡石率低、生产成本高、易卡石和针对不同湿度土壤的漏土效果不理想等问题,在传统链式捡石机上增加松土碎石装置、防卡扭力保护器等装置。以捡石率为试验指标,进行田间试验,综合分析。结果表明:(1)松土碎石装置和扭力保护装置可有效解决卡石、漏土效果不理想等问题,降低了卡石对捡石机的磨损,提高了捡石效率;(2)捡石过程稳定性良好,工作效率高,适应性强。当捡石作业深度取153 mm,捡石作业速度取1.79 m/s,栅齿入土角取27.9°时,捡石率可达最大值94.25%。

Separation of diaspore from bauxite by selective flocculation using hydrolyzed polyacrylamide

Selective flocculation is a new method to solve the problem of China's bauxite de-silication besides flotation and reverse flotation. The method of selective flocculation of bauxite using hydrolyzed polyacrylamide as flocculant was experimented and evaluated. The results of diaspore and kaolinite single mineral settling tests show that the difference between settlement yield of kaolinite(settling 15 min) and diaspore(settling 3 min) increases from 16% to 60% by adding flocculant at pH=7. Results of selective flocculation experiment of bauxite show that the higher concentrate grade(65.75) and Al-Si ratio(7.34) could be obtained with sodium carbonate as dispersant compared with sodium hexametaphosphate; under the action of flocculating agent, the concentrate grade and Al-Si ratio increase to 67.99 and 9.01. These results could meet the requirements of Bayer production, and the simpler process was expected to cost far less than traditional flotation method and a promising de-silication method of bauxite.

A review of rare earth minerals flotation: Monazite and xenotime

This paper reviews rare earth minerals(monazite and xenotime) separation by flotation. A wide range of monazite and xenotime flotation test results are summarized including: reasons of variation in the point of zero charges on these minerals, the effects of various flotation conditions on zeta potential of monazite and xenotime, interactions of collectors and depressants on the surface of these minerals during flotation separation, relationship between surface chemistry of the minerals and different types of collector adsorptions and effects of the conditioning temperature on flotation of rare earth minerals. This review collects various approaches for the selective separation of monazite and xenotime by flotation and gives perspectives for further research in the future.

Determination Method for Shear Strength Parameters of Rock-Soil Mixtures Using Close-Range Photogrammetry and 3-D Limit Equilibrium Theory

Using a combination of close-range photogrammetry and three-dimensional(3-D) limit equilibrium theory, a determination method for the shear strength parameters of rock-soil mixture is presented. A close-range photogrammetry method is used for measurement of the 3-D terrain of the experimental target. Auto CAD Lisp and EXCEL VBA are used to perform 3-D limit equilibrium analysis of the stability of sliding mass and perform backanalysis of shear strength parameters. The presented method was used to determine the shear strength parameters of rock-soil mixtures at the Liyuan Hydropower Station. The 3-D terrain of sliding surface could be measured notably well using of closerange photogrammetry. The computed results reveal that the cohesion and friction angle of rock-soil mixtures were 3.15 k Pa and 29.88o for test A, respectively, and 4.43 k Pa and 28.30o for test B, respectively, within the range of shear strength parameters, as determined by field and laboratory tests. The computation of shear strength parameters is influenced by the mesh grid number, especially the cohesion of the rock-soil mixture. The application of close-range photogrammetry can reduce the siteworks and improve the computational efficiency and accuracy.

Numerical simulation of the separation between concrete face slabs and cushion layer of Zipingpu dam during the Wenchuan earthquake

The Zipingpu concrete-faced rockfill dam(CFRD)experienced strong ground motion from the 2008 Wenchuan earthquake.Separation between concrete face slabs and the cushion layer was observed after the earthquake.The separation voids under the stage III slabs make up 55%of the total area of the stage III slabs.The observed maximum height of the separation voids was nearly 23 cm at the top of the stage III slabs.Separation voids were also observed locally below the top of stage II slabs near the left abutment,with a maximum height of 7 cm.In this study,a static and dynamic elasto-plastic finite element analysis on Zipingpu CFRD was conducted to capture the separation during the Wenchuan earthquake.The rockfill materials were described using a state-dependent elasto-plastic model that considered particle breakage.The model parameters of rockfill materials were obtained from feedback analysis.The numerical results were largely consistent with the field measurements during construction and after the Wenchuan earthquake.A three-dimensional state-dependent elasto-plastic model that can trace the separation and re-contact of a soil-structure interface was employed to investigate the interaction between concrete face slabs and a cushion layer.The analysis showed the distribution of separation voids observed in the Zipingpu CFRD has a close relationship to the water level and slab dislocations at the time of the earthquake.The phenomenon of the separation from the Wenchuan earthquake was successfully captured by the proposed numerical procedure.