三层PE防腐层涂敷中出现废层的原因

三层PE防腐层具有良好的物化性能、电绝缘性能、防水和耐化学侵蚀性能以及抗冲击性能,是目前管道较理想的防腐覆盖层。但因其造价高,至今未被广泛采用。库鄯输油管道较早地采用了三层PE防腐覆盖层工艺,积累了丰富经验。

回填废石层下放矿损贫预测及颗粒流数值分析

露天转地下开采,回填废石层在放矿过程中对矿石的损失和贫化有一定的影响。回填废石层下放矿损贫的主要影响因素有回填层厚度、废石的粒径和非均匀度3个方面,对不同试验者的实验数据重新处理,总结出了回填废石层下放矿贫化率和损失率的数学模型,并结合司家营铁矿Ⅲ采场的露天转地下工程进行了回填废石粒径与非均匀度的设计。通过颗粒流数值正交试验方法,分别从绝对因素和相对因素回归建立了贫化率λ、回填层厚度h、回填层粒径d、回填层粒径非均匀度K4个因素和损失率之间的关系,为类似条件下的回填层合理设计提供参考。

废玻璃-层布式杂纤维轻集料混凝土抗压强度试验研究

试验以轻集料混凝土为研究对象,考虑水灰比、废玻璃代砂率、塑钢纤维掺量、钢纤维体积掺量4个因素,采用L9(34)正交表进行试验设计,找出各因素对轻集料混凝土抗压强度影响的主次关系。在考虑主要因素的前提下,再采用二次曲面响应法,对试验进行进一步优化设计,运用回归分析和方差分析的方法建立了废玻璃-层布式杂纤维轻集料混凝土标准抗压强度轴心抗压强度的多元回归公式并验证了其可用性,得到了废玻璃—层布式杂纤维轻集料混凝土的优化配合比。

粘接新技术的应用

选用CH-31型胶粘剂,可使废梭和废层压打梭棒起死回生。文章介绍了采用胶粘剂粘接新技术的可行性及要求和方法。

Effect of thatch on water-soluble phosphorus of pasture soil fertilized with broiler litter

The presence of a thatch layer in established pastures could reduce the contact between broiler litter and soil, thus increasing the potential for surface runoff contamination with litter P. We conducted a laboratory study to evaluate the effect of a thatch layer on the dynamics of water-soluble P in undisturbed cores taken from a pasture. Cores with and without a thatch layer received a surface application of broiler litter (5 thm-2) and were incubated at 25 oC for 56 d. The result showed that on the soil surface the contents of water soluble-P (39 kghm-2) of the cores with the thatch layer was higher than that (20 kghm-2) of the cores without the thatch layer. Therefore on well-established pastures fertilized with broiler litter, the presence of a thatch layer might lead to high concentrations of water-soluble P on the soil surface.

Strata movement controlling effect of waste and fly ash backfillings in fully mechanized coal mining with backfilling face

A fully mechanized coal mining with backfilling (FMCMB) provides advantages of safety and efficiency for coal mining under buildings, railways, and water bodies. According to the field geological conditions, we analyzed the controlling effect of strata movement by the waste and fly ash backfilling in FMCMB face. Based on the key strata theory, we established the equivalent mining thickness model, and analyzed the action of the bulk factor of backfilling body to the equivalent mining thickness. In addition, we numerically simulated the controlling function of the strata movement by backfilling bodies with differ- ent strength. And the numerical simulation result show that the deformation of stratum and the subsi- dence of surface can be controlled by FMCMB. The result provides references to the effective execution of fully mechanized coal mining with solid waste backfilling in goaf.

特殊条件下大倾角综采工作面开采技术

峻德煤矿二采区292采煤队在首次使用综采工艺开采一水平南22-2层下行区过程中,经过采前快速培训学习,积极采取措施,克服大倾角、高瓦斯、顶板破碎、顶板采空区中有积水、顶板中有穿层废巷通过、运输系统能力受限、煤层呈向斜褶曲等困难,成功转型,并取得了良好的效果。

High voltage DC leakage detection for double-lined hazardous waste landfill based on finite element method

According to the structural characteristics of hazardous waste landfill, a new model based on the finite element method （FEM） is developed. The detection layer is considered as a sealed space and it is assumed that total current flows through the leak for the high resistivity of geomembrane liner. The leak current is regarded as a positive point current ＋I and the other current source is -I. Electrical potential of an arbitrary point in detection layer satisfies Poisson equation. Experiments for detecting leaks in liner were carried out. Excellent agreement between experimental data and simulated model data validates the new model. Parametric curves for a single leak show that with optimum selection of field survey parameters leaks can be detected effectively. For multiple leaks, the simulated results indicate that they are detectable when leak separation is larger than measurement spacing.

Treating dye wastewater by TiO_2 coated on coal cinder

We investigated the photocatalytic degradation of dye wastewater by using titanium dioxide （TiO2） coated on a coal cinder. The coal cinder was used as the carrier, with a thin film of TiO2 coated on it by using the sol-gel method. Using the Congo red as the model pollutant for dye wastewater, we studied the decolorization efficiency, and effects of TiO2 film thickness and roasting temperature on the efficiency. We also evaluated the recycling and regeneration of the immobilized TiO2 （TiO2/cinder）. Results show that the decolorization rate of Congo red solution was more than 98% after 2.h treatment when we used TiO2/cinder calcined at 500 ℃ for 2 h and coated four times as the photocatalyst. At the same time, the TiO2/cinder remained high catalytic activity after being reused and regenerated for many times.

Effects of caving–mining ratio on the coal and waste rocks gangue flows and the amount of cyclically caved coal in fully mechanized mining of super-thick coal seams

Aimed at determining the appropriate caving–mining ratio for fully mechanized mining of 20 m thick coal seam, this research investigated the effects of caving–mining ratio on the flow fields of coal and waste rocks, amount of cyclically caved coal and top coal loss by means of numerical modeling. The research was based on the geological conditions of panel 8102 in Tashan coal mine. The results indicated the loose coal and waste rocks formed an elliptical zone around the drawpoint. The ellipse enlarged with decreasing caving–mining ratio. And its long axis inclined to the gob gradually became vertical and facilitating the caving and recovery of top coal. The top coal loss showed a cyclical variation; and the loss cycle was shortened with the decreasing in caving–mining ratio. Moreover, the mean squared error(MSE) of the amount of cyclically caved coal went up with increasing caving–mining ratio, indicating a growing imbalance of amount of cyclically caved coal, which could impede the coordinated mining and caving operations. Finally it was found that a caving–mining ratio of 1:2.51 should be reasonable for the conditions.

Simulation of coupled THM process in surrounding rock mass of nuclear waste repository in argillaceous formation

To investigate and analyze the thermo-hydro-mechanical(THM) coupling phenomena of a surrounding rock mass in an argillaceous formation, a nuclear waste disposal concept in drifts was represented physically in an in-situ test way. A transversely isotropic model was employed to reproduce the whole test process numerically. Parameters of the rock mass were determined by laboratory and in-situ experiments. Based on the numerical simulation results and in-situ test data, the variation processes of pore water pressure, temperature and deformation of surrounding rock were analyzed. Both the measured data and numerical results reveal that the thermal perturbation is the principal driving force which leads to the variation of pore water pressure and deformations in the surrounding rock. The temperature, pore pressure and deformation of rock mass change rapidly at each initial heating stage with a constant heating power. The temperature field near the heater borehole is relatively steady in the subsequent stages of the heating phase. However, the pore pressure and deformation fields decrease gradually with temperature remaining unchanged condition. It also shows that a transversely isotropic model can reproduce the THM coupling effects generating in the near-field of a nuclear waste repository in an argillaceous formation.

Co-flocculation mechanism and physical model

Analysed and summarized the dynamics and chemical factors in the co (co-agulation)-flocculation process. A completely new definition for co-flocculation was given. If a colloid particle didn抰 contact with drug to emerge (physical) chemical effect, the possi-bility for the colloid particle to coagulate (flocculate) was rather small, only at the floccula-tion stage; it may be caught by net or settled by differential sedimentation. Base on sev-eral assumed important premises, the several steps and physical model of co-flocculation process were given, and the mixing, coagulation and flocculation were proposed accord-ing to their essentiality.

Landfill Site Selection in AI-Najaf Governorate, Iraq

Solid waste management aspect is one of the most important challenges facing the local administration in the Govemorate of Najaf. Therefore, this study aims to provide for solid waste management problem by choosing the best locations for the establishment of sanitary landfills in the governorate. In this study, GIS （geographic information system） and MCDA （multi-criteria decision analysis） were used based on 17 environmental, economic and geological criteria converted to input digital map layers. These were urban centres, cemetery, airports, electrical power lines, oil pipes, railways, roads, slope, historical sites, main rivers, industrial areas, religion sites, wells, military area, electrical power plants, nature reserves and national borders to select most importance sites in the govemorate. AHP （analytic hierarchy process） method was used in weighting the criteria used. All layers＇ maps were graded from 0 （not suitable） to 5 （most suitable） using spatial information scale then SAW （simple additive weighting） method was integrated in GIS used to calculate the suitability index for the studied area. The results indicated that 4.4% of the study region is suitable for landfill siting with grading values greater than 4.0. This included five sites distributed in three qadhaas of governorate.

Dye removal using some surface modified silicate minerals

The objective of this work is to study the efficiency of some surface modified phyllosilicate minerals （bentonite and glauconite） in the removal of dyes from textile waste water. It is found that complete dye removal was achieved by using 10-25g modified glauconite from solutions having a dye concentration of 10-50 mg/L. Adsorption data were modeled using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms. Adsorption capacities and optimum adsorption isotherms were predicted by linear regression method. The analysis of experimental isotherms showed that Langmuir isotherm reasonably fit the experimental data in the studied concentration range for the adsorption of dye onto glauconite mineral surface where Freundlich isotherm fit the experimental data for the adsorption of dve onto bentonite mineral surface.