等离子体协同金属氧化物催化氧化苯的研究

以Al2O3和Ag/Al2O3为催化剂,采用介质阻挡放电(DBD)反应器降解空气中低浓度的苯(C6H6),重点考察了苯的转化率、能量效率随能量密度的变化关系.研究发现:苯的氧化产物为一氧化碳(CO)和二氧化碳(CO2),当能量密度为94 J/L时,在催化剂Ag/Al2O3、Al2O3存在以及不使用催化剂的条件下,苯的能量效率分别达到了0.054 mol/kW·h、0.038 mol/kw·h与0.024 mol/kW·h.同时,探讨了国外应用低温等离子体技术处理气体污染物的相关研究成果,并与本研究做了比较.     

企业的"绿色革命"浅议

分析了加入WTO后,中国企业面临的"绿色壁垒",阐述了企业"绿色革命"的内容和措施,说明了"绿色革命"对提升企业在国际市场的竞争力的作用.     

关注国际经贸中的环境因素

当今世界环境问题倍受关注，环境问题在国际经贸中的影响日益突出，环境壁垒即绿色壁垒极有可能成为国际贸易中最重要的贸易壁垒。本文着重论述环境因素对国际经贸的影响并对本国企业如何应对提出个人对策建议。     

在较高位置构筑大型隔声屏的降噪工程

在控制工厂二层楼顶的风机群及冷却塔群的噪声工程中，复式隔声屏获１８ｄＢ（Ａ）的降噪效果。主屏由轻结构板及隔振底盘组成。主习体被若干伸缩隔断以消除热应力。副屏是为了减少主屏隔振底盘缝的漏声。迷路消声构造减少伸缩缝的漏声。为了抗风，主习必须锚固，并且屏体自身应有良好的结构。     

Infiltration and redistribution of LNAPL into unsaturated layered porous media

Enhanced understanding of light non-aqueous phase liquid (LNAPL) infiltration into heterogeneous porous media is important for the effective design of remediation strategies. We used a 2-D experimental facility that allows for visual observation of LNAPL contours in order to study LNAPL redistribution in a layered porous medium. The layers are situated in the unsaturated zone near the watertable and they are inclined to be able to observe the effect of discontinuities in capillary forces and relative permeabilities. Two experiments were performed. The first experiment consisted of LNAPL infiltration into a fine sand matrix with a coarse sand layer, and the second experiment consisted of a coarse sand matrix and a fine sand layer. The numerical multi-phase flow model STOMP was validated with regard to the experimental results. This model is able to adequately reproduce the experimental LNAPL contours. Numerical sensitivity analysis was also performed. The capillarity contrast between sands was found to be the main controlling factor determining the final LNAPL distribution.     

Geochemical techniques on contaminated sediments-river basin view

The big flood in the upper Elbe River catchment area has revealed a wide spectrum of problems with contaminated sediments. So far, an effective strategy for managing contaminated sediments on a river basin scale is still missing and it seems that not much has been learned from the lessons received during the last decade. In the following overview, special emphasis is given to the utilization of geochemically-based techniques for sediment remediation, which can be applied in different parts of a river basin. The examples presented here are mostly from the Elbe River catchment area. In general, new technical problem solutions need a set of practical process knowledge that uses a wide range of simulation techniques, as well as models in different spatial and temporal scales. The evaluation of recent flood events clearly demonstrates the importance of chemical expertise in the decision-making process for the sustainable development in river basins.     

Driver glare exposure with different vehicle frontlighting systems

Introduction: Highway safety performance at night has received less attention in research than daytime, despite the higher accident rates occurring under night-time conditions. This study presents a procedure to assess the potential hazard for drivers created by headlight glare and its interaction with the geometric design of highways. Method: The proposed procedure consists of a line-of-sight analysis performed by a geoprocessing model in geographic information systems to determine whether the rays of light that connect headlights and oncoming drivers are obstructed by either the roadway or its roadsides. Then, the procedure checks whether the non-obstructed rays of light are enclosed by a given headlight beam. Different hypotheses were set concerning the headlight beam features, including the horizontal spread angle and whether the headlights are fixed or swiveling. A highway section was selected to test and validate the procedure proposed. A 3D recreation of the highway and its environment derived from a LiDAR point cloud was used for this purpose. Results: The findings disclose how glare is produced on tangents, horizontal curves, transitions between them and sequences of curves. The effect of visual obstructions conveniently placed is also discussed. Conclusions: A greater glare incidence is produced as the horizontal headlights spread angle increases. Swiveling headlights increase glare on highways left curves and reduce it on right curves. Practical Applications: The procedure and conclusions of this study can contribute to develop more effective glare avoidance technologies as well as identify and assess glare-prone sections. The glare evaluation assists in evaluating glare countermeasures such as deciding whether to place a vegetation barrier and where.     

Investigating the influence on safety of retrofitting Italian motorways with barriers meeting a new EU standard

Objective: A new European Union (EU) regulation for safety barriers, which is based on performance, has encouraged road agencies to perform an upgrade of old barriers, with the expectation that there will be safety benefits at the retrofitted sites. The new class of barriers was designed and installed in compliance with the 1998 (European Norm) EN 1317 standards for road restraint systems, which lays down common requirements for the testing and certification of road restraint systems in all countries of the European Committee for Standardization (CEN). Both the older and new barriers are made of steel and are installed in such a way as to avoid vehicle intrusion, but the older ones are thought to be only effective at low speeds and large angles of impact. The new standard seeks to remedy this by providing better protection at higher speeds. This article seeks to quantify the effect on the frequency of fatal and injury crashes of retrofitting motorways with barriers meeting the new standards.

Methods: The estimation of the crash modification was carried out by performing an empirical Bayes before–after analysis based on data from the A18 Messina–Catania motorway in Italy. The methodology has the great advantage to account for the regression to the mean effects. Besides, to account for time trend effects and dispersion of crash data, a modified calibration methodology of safety performance was used.

Results: This study, based on data collected on 76 km of motorway in the period 2000–2012, derived Crash Modification Factor point estimates that indicate reductions of 72% for run-off-road fatal and injury crashes and 38% in total fatal and injury crashes that could be expected by upgrading an old safety barrier by complying with new EU 1317 standards. The estimated benefit-cost ratio of 5.57 for total crashes indicates that the treatment is cost effective.

Conclusions: The magnitude of this benefit indicates that the retrofits are cost-effective even for total crashes and should continue in any European country inasmuch as the estimated Crash Modification Factors are based on treatment sites that are reasonably representative of all European motorways.     

Adsorption-oxidation of hydrogen sulfide on Fe/walnut-shell activated carbon surface modified by NH3-plasma

Walnut-shell activated carbon(WSAC) supported ferric oxide was modified by non-thermal plasma(NTP), and the removal efficiency for hydrogen sulfide over Fe/WSAC modified by dielectric barrier discharge(DBD) was significantly promoted. The sample modified for10 min and 6.8 k V output(30 V input voltage) maintained 100% H2 S conversion over a long reaction time of 390 min. The surface properties of adsorbents modified by NTP under different conditions were evaluated by the methods of X-ray photoelectron spectroscopy(XPS), Brunauer–Emmett–Teller(BET) analysis and in-situ Fourier transform infrared spectroscopy(FTIR), to help understand the effect of the NTP treatment. NTP treatment enhanced the adsorption capacity of Fe/WSAC, which could due to the formation of micro-pores with sizes of0.4, 0.5 and 0.75 nm. XPS revealed that chemisorbed oxygen changed into lattice oxygen after NTP treatment, and lattice oxygen is beneficial for H2 S oxidation. From the in-situ FTIR result,transformation of the reaction path on Fe/WSAC was observed after NTP modification. The research results indicate that NTP is an effective method to improve the surface properties of the Fe/WSAC catalyst for H2 S adsorption-oxidation.     

鼓楼立交桥交通噪声分析及声屏障设计

通过对鼓楼立交桥机动车流量的实测。运用高架桥交通噪声预测数学模型，对鼓楼立交桥交通噪声剖面分布和地面分布进行了分析。经过计算声程差，得出合理的利用声屏障技术来解决鼓楼立交桥交通噪声问题是可行的。