Metal-doped carbon aerogels as catalysts during ozonation processes in aqueous solutions

The efficiency of Co(II)-, Mn(II)-, and Ti(IV)-doped carbon aerogels for the transformation of ozone into (*)OH radicals was investigated. The carbon aerogels had a markedly acid surface character (pH(PZC approximately equal) congruent with 3-4) with very high surface oxygen concentrations (O approximately equal with 20%). X-ray photoelectron spectroscopy (XPS) analyses of the samples showed the oxidation state of the metals was +2 for Co and Mn and +4 for Ti. The presence of Mn(II)-doped carbon aerogel enhanced ozone transformation into (*)OH radicals, whereas the presence of Co(II) and Ti(IV) carbon aerogels presented no activity in this process. Moreover, it was observed that an increase in the concentration of Mn in the surface of the aerogel increases its efficiency to transform ozone into (*)OH radicals, with an Rct value ([OH]/[O(3)]) of 5.36 x 10(-8) for the aerogel doped with 16% of surface Mn(II) compared to an R(ct) of 2.68 x 10(-9) for conventional ozonation. Regardless of the aerogel used, XPS analysis of the ozonated aerogel samples showed an increase in the concentration of surface oxygen when the exposure to ozone was longer. However, presence of oxidized metal species after ozone treatment was only detected in the case of the Mn-doped aerogel, (Mn(III) and Mn(IV)). CO(2) activation of carbon aerogel produced a marked increase in its efficiency to transform ozone into (*)OH radicals compared with non-activated sample. The efficiency of Mn activated carbon aerogel to transform ozone into (*)OH radicals was greater than that of Witco commercial activated carbon or H(2)O(2) in the ozonation of water from Lake Zurich (Zurich, Switzerland).     

Efficiency of activated carbon to transform ozone into *OH radicals: influence of operational parameters

Based on previous findings (Jans, U., Hoigné, J., 1998. Ozone Sci. Eng. 20, 67-87), the activity of activated carbon for the transformation of ozone into *OH radicals including the influence of operational parameters (carbon dose, ozone dose, carbon-type and carbon treatment time) was quantified. The ozone decomposition constant (k(D)) was increased by the presence of activated carbon in the system and depending on the type of activated carbon added, the ratio of the concentrations of *OH radicals and ozone, the R(ct) value ([*OH]/[O3]), was increased by a factor 3-5. The results obtained show that the surface chemical and textural characteristics of the activated carbon determines its activity for the transformation of ozone into *OH radicals. The most efficient carbons in this process are those with high basicity and large surface area. The obtained results show that the interaction between ozone and pyrrol groups present on the surface of activated carbon increase the concentration of O2*- radicals in the system, enhancing ozone transformation into *OH radicals. The activity of activated carbon decreases for extended ozone exposures. This may indicate that activated carbon does not really act as a catalyst but rather as a conventional initiator or promoter for the ozone transformation into *OH radicals. Ozonation of Lake Zurich water ([O3] = 1 mg/L) in presence of activated carbon (0.5 g/L) lead to an increase in the k(D) and R(ct) value by a factor of 10 and 39, respectively, thereby favouring the removal of ozone-resistant contaminants. Moreover, the presence of activated carbon during ozonation of Lake Zurich water led to a 40% reduction in the content of dissolved organic carbon during the first 60 min of treatment. The adsorption of low concentrations of dissolved organic matter (DOM) on activated carbon surfaces did not modify its capacity to initiate/promote ozone transformation into *OH radicals.     

NLP-based faceted search: Experience in the development of a science and technology search engine

An appropriate promotion, distribution and dissemination of scientific, artistic and technology developments can foster the collaboration between a country’s productive and academic sectors. The purpose of this paper is to present a novel search engine aiming at helping people to access science and technology advances, researchers and institutions working in specific areas of research. Our search engine first collects information disseminated on the Web in academic institution sites and in researchers personal homepages. Then, after intensive text processing, it summarizes the information in an enriched and user-friendly presentation oriented to non-expert users. Stable performance and an acceptable level of effectiveness for automatic named entities recognition indicate the potential of our approach for bridging the gap between the heterogeneous and unstructured information available on the Web about the research and development advances in a country and the innovation required by the productive sectors.     

面向按序执行处理器的预执行机制设计空间探索

面向按序执行处理器开展预执行机制的设计空间探索,并对预执行机制的优化效果随Cache容量和访存延时的变化趋势进行了量化分析.实验结果表明,对于按序执行处理器,保存并复用预执行期间的有效结果和在预执行访存指令之间进行数据传递都能够有效地提升处理器性能,前者还能够有效地降低能耗开销.将两者相结合使用,在平均情况下将基础处理器的性能提升24.07%,而能耗仅增加4.93%.进一步发现,在Cache容量较大的情况下,预执行仍然能够带来较大幅度的性能提升.并且,随着访存延时的增加,预执行在提高按序执行处理器性能和能效性方面的优势都将更加显著.     

基于性能预报技术减少热轧带钢取样频率的探索

性能预报技术是一件具有深远影响的技术,但实现在线应用需系统考虑解决一些约束问题,目前在线应用的报道并不多见。宝钢研究了一种基于性能预报模型对现有热轧产品取样管理流程的优化方法,它通过建立带钢力学性能预报模型,将产品取样管理流程与带钢的实际生产过程相关联,对多数合格带钢实现预报替代取样,而对少数异常带钢进行有针对性地实际取样,从而达到减少取样频率的目的。基于现有生产执行系统（MES系统）的应用实践,探索出一套基于性能状态优化中间品采样频率的方案,实现了性能预报模型的大生产在线应用。该方法依托信息技术和统计技术,既实现了取样的精细化管理,又降低了运营成本。实际应用效果表明,基于性能预报模型的新取样管理方法不但没有降低可靠性,而且可以降低69%的中间品取样量;新方法在加快生产物流上效果也非常明显,可以节省23 h,这些都说明该方法是一项具有实际应用价值的技术。     

A Bold Vision and a Brand Identity for the Planning Profession

R. W. Firestone's Cityscape Pink is a bold image capturing the essence of a city. In this Longer View essay, Bruce McClendon argues that the profession of planning needs a similarly bold vision and compelling brand identity in order to claim its proper place among many competitors offering similar services. He aims to distinguish the planning profession in the eyes of the public and the minds of planners themselves. Three commenters respond with different perspectives on the status of the profession and how best to improve it.

Firestone is a psychotherapist with a PhD in clinical psychology from the University of Denver and the author of nine books. He grew up in the New York City area and opened his private practice in Los Angeles, treating patients suffering from schizophrenia. With a group of friends he has sailed to many parts of the world, and both his practice and his travels figure into the subjects of his artwork.

Planning has become a generic product in a confusing, overcrowded, and highly competitive marketplace. The public does not know what planning is or how to differentiate among planning specialists. Relying on a bold back-to-the-future approach, I argue that it is the production, administration, and implementation of comprehensive plans that once was and still is the profession's unique and distinctive technical competency and core mission. By using branding techniques to define, link, and reconnect planners with comprehensive planning, it will be possible to tell the planning story in a way that communicates the emotional benefits and value of the profession and strengthens the public's respect and appreciation for planners.     

Identification of structural entities in NdF3-LiF melts with cryoscopic method

Nd-F species in NdF3-LiF melts were studied using cryoscopic method.Liquidus temperatures of melts of various compositions were determined by differential thermal analysis(DTA).Based on the different model calculations,NdF4- was identified as the most likely Nd-F entity in the melts in which the mole fraction of NdF3 was lower than 20%,considering only one single Nd species in the melt,and which was formed in accordance with Temkin model or Flood model.Then,activities of different components in the melts were researched.The results show that activity of LiF decreases,and that of NdF3 increases with increasing the mole fraction of NdF3.The value of activity coefficient of NdF3 is higher than 1,and that of LiF is lower than 1.     

水电工程征地移民实物指标管理系统的设计与实现

水电工程移民管理业务中产生了大量的数据,特别是所涉及的移民实物指标种类繁多,数据量较大.在当今管理要求不断提高和信息技术日益普及的环境下,传统的手工操作方式已经不能满足移民精细化管理工作的要求,必须采用先进的技术手段和工具提高工作的效率.结合系统开发的实际情况,介绍了水电工程征地移民实物指标管理系统的设计开发、组织、规范和工具等情况,对系统所实现的功能进行了分析,为该系统的推广使用创造了一定的条件.     

中国水量分配研究进展

随着农业现代化发展,新型农业经营主体大量涌现,逐步参加和主导了农田水利工程运行维养,并对传统运行维养模式转变产生了积极影响。通过对新型农业经营主体及供销合作组织参与农田水利工程建设、维养情况,存在的问题和难点等分析,提出了鼓励扶持的意见和建议,为创新农田水利工程运行维养模式,深化农业水价综合改革提供有益的参考。     

Numerical studies of a tube-in-tube helically coiled heat exchanger

In the present study a tube-in-tube helically coiled (TTHC) heat exchanger has been numerically modeled for fluid flow and heat transfer characteristics for different fluid flow rates in the inner as well as outer tube. The three-dimensional governing equations for mass, momentum and heat transfer have been solved using a control volume finite difference method (CVFDM). The renormalization group (RNG) k– model is used to model the turbulent flow and heat transfer in the TTHC heat exchanger. The fluid considered in the inner tube is compressed air at higher pressure and cooling water in the outer tube at ambient conditions. The inner tube pressure is varied from 10 to 30 bars. The Reynolds numbers for the inner tube ranged from 20,000 to 70,000. The mass flow rate in the outer tube is varied from 200 to 600 kg/h. The outer tube is fitted with semicircular plates to support the inner tube and also to provide high turbulence in the annulus region. The overall heat transfer coefficients are calculated for both parallel and counter flow configurations. The Nusselt number and friction factor values in the inner and outer tubes are compared with the experimental data reported in the literature. New empirical correlations are developed for hydrodynamic and heat-transfer predictions in the outer tube of the TTHC.