响应曲面法优化固相反硝化的工艺条件

以一种新型可降解材料PLA/PHBV共混物为碳源和生物膜载体,对硝酸盐污染水进行反硝化脱氮。在温度为(29±1)℃,pH为(7.5±0.2)条件下,利用响应曲面法考察了进水硝态氮浓度、水力停留时间(HRT)和出水硝态氮浓度之间的关系,建立了以出水硝态氮浓度为响应值的二次多项式回归模型,模型预测值与实验值能很好吻合。方差分析结果表明,进水硝态氮浓度和HRT及其交互作用对响应值均具有显著性影响(P<0.01)。     

Box-Behnken响应曲面优化铁炭微电解降解结晶紫

在单因素实验的基础上,以结晶紫脱色率为评价指标,铁炭比、反应时间与曝气量为考察因素,采用Box-Be-hnken响应曲面法优化铁炭微电解降解结晶紫的工艺条件,同时得出相应的数学模型。实验表明,在结晶紫初始浓度为100mg/L和体积为300 mL,pH为3,反应时间为80 min,铁屑的投加量为20 g,铁炭质量比为2∶1,曝气量为20 L/h的条件下,铁炭微电解对结晶紫的脱色率可达到89.6%。通过Box-Behnken响应曲面可知,铁炭比、反应时间、曝气量以及铁炭比和反应时间的交互作用对结晶紫的脱色率均有显著影响,其中曝气量对脱色率的影响尤为显著;回归模型决定系数R2=0.9067,P=0.039,表明此模型拟合程度良好,且模型显著。铁炭微电解降解结晶紫最佳的工艺条件为:铁炭比为2.4∶1,反应时间为84 min、曝气量为40 L/h,脱色率为93.25%,回归模型的预测值与测定值偏差率为2.26%。     

超临界水氧化处理垃圾渗滤液的响应面法优化

在间歇式反应釜上采用超临界水氧化法处理垃圾渗滤液.运用中心组合设计研究了反应温度（400~500 ℃）、压力（24~28 MPa）、反应时间（5~10 min）和氧化系数（1.5~2.5）,以及它们的交互作用对COD、氨氮去除率的影响,同时通过响应面法分析拟合出COD、氨氮去除率的二次回归方程,得到最优工艺条件.结果表明,各因素对COD去除率的影响主次作用排序为：反应压力>温度>氧化系数>反应时间;各因素对氨氮去除率的影响主次作用排序为：反应温度>压力>氧化系数>反应时间,而影响因素之间的交互作用对两者去除效果的影响却不明显.所得拟合方程对COD、氨氮去除率的预测误差分别小于±4%、±9%.拟合方程所得最佳实验条件为：时间5 min、温度496.05 ℃、压力27.69 MPa、氧化系数2.44,此时COD的去除率可以达到98.31%、氨氮去除率可以达到95.69%.     

Implementation of a software platform to support an eco-design methodology within a manufacturing firm

The paper aims to explore the implementation of an eco-design methodology and the related software platform (G.EN.ESI – Green ENgineering dESIgn) within technical departments of a manufacturing firm. The G.EN.ESI eco-design methodology is based on the life cycle thinking concept and the software platform is conceived as a set of inter-operable software tools able to efficiently exchange data among them and with the traditional design systems (i.e. CAD, PDM and PLM). A multinational company, designing and producing household appliances, adopted the proposed methodology and related software platform for redesigning two cooker hood models with the aim to improve their environmental performances. Design and engineering departments evaluated the methodology and platform impact on the product development process, as well as the platform inter-operability with traditional design tools. The results indicate that methodology and software platform satisfy the requirements of the enterprise in terms of: (i) degree of expertise and training requirement on this subject, (ii) low impact in a consolidated design process and, (ii) good level of inter-operability among heterogeneous tools. However, the testing results highlight the necessity of a further platform optimisations in terms of software integration (single workbench made by integrated software tools with the same graphical user interface).     

The sustainability of China's major mining cities

The aim of this paper is to identify principal factors controlling the Degree of Sustainable Development of Mineral Resources (DSDMR) of mining cities and then to measure their DSDMR and reveal their developing trends. To do this, 78 Chinese mining cities are used as an example. These cities are classified on a hierarchical level of the DSDMR in order to support decision-making of sustainable development. Six principal factors controlling the DSDMR are recognized using factor analysis. They are used to measure the DSDMR of the Chinese mining cities and their developing trends. The results show that in terms of the type of mineral resources, the DSDMR decreases from petroleum to multi-resources to non-metal to coal to metal cities. It decreases also from middle to old to young aged cities and from eastern to central to western cities in geographical location. In addition, large and very large cities have higher DSDMR values than middle- and small-sized cities. These Chinese mining cities are classified into six clusters by cluster analysis, which forms the basis for policy making.     

Mineral economics: Overview of a discipline

Mineral economics is the academic discipline that investigates and promotes understanding of economic and policy issues associated with the production and use of mineral commodities. While its origins can be traced back at least 200 years to the writings of David Ricardo and other early Classical economists, it emerged as a separate academic field only after World War II and then primarily in the United States. As a separate academic discipline, its roots are found in mining schools that needed to consider the milieu in which minerals are sold. While geologists, mining engineers, and others with technical backgrounds were largely responsible for creating the first stand-alone mineral-economics programs, ultimately trained economists became participants as well. Moreover, even after the rise of mineral-economics departments, most of the research in the field continued and continues to be carried out in other academic units, including traditional economic departments and engineering schools, as well as in government agencies, nonprofit research organizations, consulting firms, and international organizations.     

The supply behaviour of state mining enterprises: A case study of the Jordanian phosphate industry

An important feature of export-oriented production in mineral-rich developing countries for almost three decades after 1960 was the growth of state-owned enterprises. For the phosphate industry, this was reflected in the expansion of companies such as Office Cherifienne des Phosphate (OCP) in Morocco and the Jordan Phosphate Mines Company (JPMC). There was a strategic importance of the industry for these nations and the large capital outlays necessary for phosphate and fertilizer production expansion often required considerable government assistance because of the perceived high risks of private investment in the industry.     

Broadening the statistical search for metal price super cycles to steel and related metals

During the past five years, industry analysts have proclaimed that metal prices are in the early phase of a ‘super cycle,’ driven primarily by Chinese industrial expansion. Academic economists have generally been very skeptical about the presence of long cycles. A time-series econometric analysis by Cuddington and Jerrett [2008. Super cycles in real metals prices? IMF Staff Pap. 55(4), in press], however, has used band-pass filtering techniques to isolate super cycles in the prices of six metals traded on the London Metal Exchange (the ‘LME6’). This paper extends the search for super-cycle behavior to three additional metal products that are critical in the early phases of industrial development and urbanization: steel, pig iron, and molybdenum (a key ingredient in many steel alloys). There is strong evidence of super cycles in these three metals, although their timing differs to some extent from the super cycles found for the LME6.     

土壤中有机污染物迁移行为的研究方法

土壤中的有机污染物可能影响土壤的正常功能,甚至造成地下水、大气和食物链的污染,对人类健康和环境质量产生威胁。研究有机污染物在土壤中的迁移行为,对于了解其进入土壤后的归趋,评价土壤环境质量,进行污染防治具有重要意义。本文分类介绍了研究土壤中有机污染物迁移行为的各种方法,认为建立条件控制良好的模拟实验体系是进行此类研究的重要手段。     

生命价值评估与死亡赔偿

在成本-收益分析过程中,生命价值评估为政府确定公共政策收益提供依据。论述生命价值的基本涵义;用劳动市场上的内涵工资法通过分析工资-风险均衡关系来研究生命统计价值,在工人的期望效用曲线与企业的等利润曲线的切点上,企业正常经营,工人实现期望效用最大化。通过对提供曲线求导得到生命价值。生命价值并不针对确定的死亡问题,把生命价值作为死亡赔偿的依据,是对生命价值概念的误解,混淆了生命价值的应用范围。我国法律法规以收入水平为基础确定意外死亡赔偿标准,其实质是人力资本法。