预制混凝土U型槽在寒区渠道防渗中的应用

阐述了混凝土U型槽的防渗特点和在施工中应注意的问题。     

焦作矿区煤层瓦斯合理预抽期的研究

主要介绍了合理预抽期确定模型在焦作矿区的应用。为了减少瓦斯突出的危险性,合理地确定预抽期是瓦斯抽放的关键因素之一。     

瓦斯管安设中大偏口的成功应用

瓦斯管弯头的安设不仅消耗了大量材料,而且增加了抽放阻力。现改用大偏口代替弯头,不仅节约材料,而且降低了抽放阻力,为做好瓦斯抽放工作打下了坚实的基础。     

瓦斯抽放系统在排放密闭巷道瓦斯过程中的应用

瓦斯抽放的方法有本煤层抽放、邻近层抽放和采空区抽放。传统排放密闭内的瓦斯方法是控制风流排放法,但如何安全、可靠排放密闭巷道内瓦斯问题却有待探索。文章就如何对密闭巷道内的瓦斯进行抽排作浅显论述。     

严寒环境下排水管线施工方法

严寒环境下排水管道施工问题一直是困扰施工单位和建设单位的一大难题。作者在长期的施工和设计工作中,总结出以下严寒环境下排水管线施工方法,即管道的防腐、焊接、检查井井盖等重点施工项目集中保护处理;管沟开挖、回填及管道闭水试验快速处理;检查井及检查井进出水管制作及连接特殊处理的方法,从而保证整个工程施工质量合格,并且节省工程费用,保障施工单位和建设单位的经济利益不受损失。     

Estimation of temporal changes in oxidation rates of sulphides in copper mine tailings at Laver, Northern Sweden

Tailings containing pyrrhotite were deposited in an impoundment at a copper mine at Laver, Northern Sweden, which operated between 1936 and 1946. Since then the oxidation of sulphides has acidified recipient water courses and contaminated them with metals. Measurements from surface water sampled in 1993, 2001 and 2004-05 from a brook into which the tailing impoundment drains indicate that the amounts of sulphide-associated elements such as Cu, S and Zn released into the brook have decreased over time, while pH has increased. The mass transport of S in the brook during 1993 and 2001 corresponded well with the amount of S estimated to be released from the tailings by oxidation. Secondary precipitates such as covellite and gypsum, which can trap sulphur, were shown in earlier studies to be present in only low amounts. The annual release of elements from the tailings was estimated from the volume of tailings assumed to oxidise each year, which depends on movement of the oxidation front with time. The results indicate that the oxidation rate in the tailings has decreased over time, which may be due to the increased distance over which oxygen needs to diffuse to reach unoxidised sulphide grains, or their cores, in the tailings.     

Asphaltene Deposition During Steam-Assisted Gravity Drainage: Effect of Non-Condensable Gases

Asphaltene deposition was investigated during laboratory-scale steam-assisted gravity drainage (SAGD) experiments to probe in situ upgrading of a heavy oil. Tests were conducted with and without the addition of non-condensable gases (carbon dioxide or n-butane) to the steam. The apparatus was a three-dimensional scaled physical model packed with crushed limestone saturated with 12.4° API heavy-crude oil. Temperature, pressure, and production data, as well as the asphaltene content of the produced oil, were monitored continuously during the experiments. For small well separations, as the fraction of non-condensable gas in the steam increased, the steam condensation temperature and the steam-oil ratio decreased. As a result of lower temperature, the heavy oil was less mobile in the steam chamber relative to pure steam injection. Thus, the heating period was prolonged and the recovery, as well as the rate of oil recovery, decreased. Asphaltene content of the oil produced as a result of pure steam injection decreased initially showing deposition of asphaltene within the porous matrix of the model. As the steam injection continued, the asphaltene content of the produced oil increased but remained below the initial value. Thus, the produced oil indicated some in situ upgrading. As the carbon dioxide concentration in the steam increased, greater asphaltene deposition occurred; however, no significant change in asphaltene content was found when n-butane was added to the steam. Post-experimental analyses of the porous media for asphaltene content confirmed retention for the pure steam and steam with added CO₂ experiments. Numerical simulation of the asphaltene deposition process using a pure solid deposition model corroborated experimental findings and showed that deposition occurred mainly at the steam-chamber boundary.     

支持向量机模型在渗流监测中的应用

提出了基于一种支持向量机(SVM)的渗流监测方法。该方法采用结构风险最小化原则，能够在对小样本学习的基础上，对其他样本进行快速、准确的拟合预测，具有更好的泛化性能和精度，减少了对经验的依赖。在算例中，基于SVM的非线性特点，根据土石坝的实测资料建立了渗流监测模型，为水头预报和安全监测奠定了基础。     

陶瓷脱水元件及其在长网纸机上的应用

本文着重探讨当今世界流行的几种陶瓷脱水元件及其常用的结构,并以实际例子说明它在长网纸机上的应用情况以及取得的经济效益。     

乌龙泉矿尾矿库的治理

介绍了乌龙泉矿尾矿库治理的具体方法 ,详细地阐述了回收利用石灰石、白云石洗矿尾矿的回收利用和采用辐射井排渗固结技术加固主坝等新工艺。