武夷新区综合管廊的建设与发展

随着社会的发展以及城市化水平的提高,城市综合管廊逐渐以系统的形式建立起来,对城市的发展以及人民的生产与生活起着至关重要的作用。本文对福建省综合管廊现状进行分析,通过对比介绍武夷新区综合管廊项目情况,为其他类似工程提供参考。     

广西某复杂铜铅锌多金属硫化矿石选矿试验

广西某复杂铜铅锌多金属硫化矿石铜、铅、锌、硫、银含量分别为0.64%、0.46%、1.66%、10.08%、33.99g/t,主要金属矿物为黄铜矿、方铅矿、闪锌矿、黄铁矿,矿石中金属矿物之间共生关系密切、嵌布粒度不均匀。为确定该矿石的高效开发利用工艺,进行了选矿试验。结果表明:在磨矿细度为-74μm占75%情况下,采用1粗2精2扫铜铅混浮—1粗1精1扫铜铅分离—1粗1精2扫浮锌—1粗1精1扫浮硫流程处理矿石,可获得Cu品位为23.76%、铜回收率为83.93%、Ag品位为556.76 g/t、Ag回收率为36.81%的铜精矿,Pb品位为48.23%、Pb回收率为64.81%、Ag品位为1 651.76 g/t、Ag回收率为30.49%的铅精矿,Zn品位为45.81%、Zn锌回收率为88.49%、Ag品位为71.34 g/t、Ag回收率为6.69%的锌精矿,以及S品位为44.75%、S回收率为81.39%、Ag品位为37.71 g/t、Ag回收率为20.34%的硫精矿,实现了铜、铅、锌、银、硫的高效综合回收。     

云南某低铜贫铁矿石选铜试验

云南某低铜贫铁矿石铜含量为0.35%、铁含量为19.22%,91.43%的铜为硫化铜。对该矿石中铜的选矿工艺进行了研究。结果表明,矿石在磨矿细度为-200目占80%的情况下,以TX-31为浮铜捕收剂,经1粗2扫3精、中矿顺序返回流程处理,获得了铜品位和铜回收率分别为22.48%和91.20%的铜精矿,较好地实现了铜的回收,选铜铁损失率仅为2.18%,为后续选铁创造了条件。     

Greenhouse gas emissions from the international maritime transport of New Zealand's imports and exports

Greenhouse gas emissions from international maritime transport are exempt from liabilities under the Kyoto Protocol. Research into quantifying these emissions is ongoing, and influences policy proposals to reduce emissions. This paper presents a cargo-based analysis of fuel consumption and greenhouse gas emissions from New Zealand's international maritime transport of goods. Maritime transport moves 99.5% (by mass) of New Zealand's internationally traded products. It is estimated that 73% of visiting vessels' activity can be directly attributed to the movement of goods in and out of New Zealand. A cargo-based methodology was used to estimate that the international maritime transport of New Zealand's imports and exports consumed 2.5 million tonnes (Mt; 2.6 billion litres) of fuel during the year 2007, which generated 7.7 Mt of carbon dioxide (CO₂) emissions. Double-counting of emissions would occur if a similar method was applied to all New Zealand's trading partners. In contrast, since few large vessels refuel in New Zealand, the National Greenhouse Gas Inventory listed 2007 international maritime transportation emissions as 0.98 Mt of CO₂, calculated from fuel bunkered for international transport. The results, therefore, show a significant difference between activity-based and bunker-fuel methodologies in quantifying New Zealand's emissions. International policy implications are discussed.     

A simple method to reduce the start-up period in a H2-producing UASB reactor

Introduction of an up-flow anaerobic sludge blanket (UASB) reactor apparatus to fermentative hydrogen production (FHP) enormously improves H₂ production performance. However, the long start-up period required to form H₂-producing granules (HPG) remains as a major obstacle. In the present work, a completely-stirred tank reactor (CSTR) was operated for 7 days, and the mixed liquor in the CSTR was transferred to a UASB reactor (UASBr (I)) as a seeding source. Coffee drink manufacturing wastewater (CDMW) was used as a feedstock, constituting the first attempt to form HPG from actual industrial wastewater. The strategy employed here was found to be more effective in developing HPG than directly starting from the UASB reactor (UASBr (II)), which is attributed to substantially higher active mass transfer in the CSTR. The average size of particles in the UASBr (II) blanket zone after 50 days of operation corresponded with that in the CSTR after only 7 days of operation. The drastic decrease of extracellular polymeric substance (EPS) protein concentration in the CSTR operation also indicates efficient removal of non-active biomass, the presence of which could adversely affect HPG formation. UASBr (I) showed a stable H₂ yield and H₂ production rate of 1.78 mol H₂/mol hexose_added and 2.76 L H₂/L/h, respectively, and HPG with an average size of 1.9 mm were developed after 45 days. It appears that the abundant presence of divalent ions, especially calcium ions, contained in the CDMW facilitated HPG formation.     

MAC层速率控制机制研究综述

802.11网络MAC速率控制机制根据信道质量动态地选择传输速率,对吞吐量的提升起着决定作用。针对MAC层速率控制机制进行综述研究,介绍各种速率控制机制的工作原理并分析其优缺点,总结了速率控制机制设计经验,并对速率控制机制的发展方向进行了展望。     

降温速率对零度以上介质内甲烷水合物形成的影响

在自然界中,天然气水合物主要以散布状、斑块状和层状构造形式赋存于各种沉积物中,沉积介质对赋存于其中的天然气水合物的性质具有显著影响.采用12℃→0.5℃/3h和12℃→0.5℃/50h 2种降温方法在非饱和粗砂、粉土内分别形成甲烷水合物,以考察降温速率对介质内甲烷水合物生成形态及形成性质的影响.通过实验指出:改变降温速率不影响水合物最终生成形态;缓慢降温利于甲烷水合物在介质内集中生成且形成范围更大.     

支撑函数法在凸轮机构学中的若干重要新应用

将"支撑函数法"向偏置式凹圆弧底、负半径滚子直动从动件盘形凸轮机构作延拓推广,巧妙和成功得到了凸轮轮廓曲率半径、外凸性判据、参数方程、周长和面积等一整套通用计算公式.不仅发展、深化了对新型凸轮机构的理解和认识,亦将支撑函数法延拓和推广成为一种为凹圆弧底和负半径滚子从动件盘形凸轮机构所共享的理论研究框架.     

苏州市高新区给水管网水力模型的建立与应用

以三高宏扬给水管网水力模拟软件为模型搭建平台,建立了苏州市高新区给水管网水力模型。选取部分监测管段与节点,从压力、流量角度对模型进行了校核。运用校核合格的模型模拟了管网现阶段压力、流速运行状况,并针对服务区域低压区、低速区分析了现阶段管网可能产生的问题,提供了改建的建议。结果表明,给水管网水力模型的建立能为供水企业相关的调度管理工作提供技术参考。