Effect of seaweed proliferation on benthic habitat quality assessed by Sediment Profile Imaging

Changes in sediment quality, with special reference to benthic habitat conditions resulting from macroalgae overgrowth, were studied in the Venice Lagoon, Italy. Data were collected biweekly in spring and summer from 1993 to 1998 and from 2001 to 2002, as part of the macroalgae growth control strategies managed by the Venice Water Authority-Consorzio Venezia Nuova. Benthic habitat conditions were studied by means of Sediment Profile Imaging, which allowed the collection of several variables: aRPD (apparent redox potential discontinuity), prism penetration depth, presence of anoxia on the surface of the sediment, presence of reduced gas bubbles, stage of benthic colonization. All these variables led to the calculation of an environmental index (Organism–Sediment Index, OSI), which was then related to physical variables and macroalgae abundance. Until 1996, the overall benthic habitat of the Venice Lagoon showed almost stressed conditions; from 1997, the seaweed biomass rapidly declined and the OSI increased significantly. The OSI seemed to be affected by seaweed biomass, sediment compactness and water depth. Macroalgae biomass greater than 4.5 kg/m² led to the complete disappearance of stage III of benthic colonization; values as low as 0.70 kg m² already had a severe impact on recolonization. SPI attributes indicated the main mechanisms that could have contributed to the benthic quality: seaweed proliferation is often followed by rapid decay of macroalgae biomass, especially when present in large amounts. The decrease in seaweed biomass often results in oxygen depletion in the water column and thus in the sediment, preventing complete benthic colonization. This research confirms the importance of in situ rapid reconnaissance surveys to assess the impact of eutrophication on the benthic habitat.     

利用列车比例模型风洞试验研究基础设施对列车气动力的影响

为了明确铁路轨道沿线横风所造成的危险,就必须探讨基础设施对列车气动载荷的影响.本文介绍了在标准的TSI基础设施(有碴轨道和无碴轨道以及6 m高路堤)和标准的意大利高架桥路面上,通过风洞试验所测试的ETR 500列车的气动力系数.每一种基础设施的特性都分为有列车和无列车2种状况进行研究.通过对比不同情况下的试验结果,指出...     

The possible designation of the Mediterranean Sea as a SECA: A case study

In view of the ongoing discussions concerning the possible designation of the Mediterranean Sea as a Sulphur Emission Control Area (SECA), a modal split model was applied to a case involving the transportation of consolidated cargoes between Thessaloniki, Greece and industrial hubs of northern Germany. A road-only option was assessed against a combined-transport route involving a ferry (Greece–Italy) and a truck-on-train (Italy–Austria) service. The logit model used considers two variables as determinants of the modal selection: transport cost and time. The data are derived from interviews with a small transport service provider, typical for Greece, and are based on actual trips made (revealed preferences). The results predict that the designation of the Mediterranean as a SECA will cause a modal shift in favour of the road-only route by 5.2%, which under certain assumptions can reach 17.1%. However, the environmental implications of the resulting modal choices, calculated through the EcoTransIT World web based tool, are positive in relation to all emissions examined. This is attributed to the longer distance of the combined-transport option in comparison to the road-only one and, the poor environmental performance of the Ro-Pax vessels basically due to the need to maintain a relatively high speed.     

意大利摩托车和轻便摩托车市场最新发展情况

意大利是欧洲最大的两轮机动车市场,意大利的摩托车、轻便摩托车产业也一直处于世界领先地位,技术含量较高,从20世纪初开始,意大利就涌现出许多著名的摩托车品牌。虽然2010年意大利摩托车销量下滑,但全年注册量仍位于欧洲首位。     

意大利岩土控制变形(ADECO-RS)工法简介

岩土控制变形(ADECO-RS)工法,是一种系统的全断面机械化开挖的隧道设计、施工技术。该工法被意大利公路及铁路领域纳入规范并且被广泛采用,欧洲国家的大型项目施工也较多地采用此工法。文章系统地介绍了其以控制掌子面超前核心土变形为手段的主要理念、施工原则及施工方法。     

Application of the Principles of ICZM for Restoring the Goro Lagoon

The Goro lagoon has been adversely affected by intense anthropogenic impacts, which have resulted in deterioration of the lagoon's environmental health. An intervention at the lagoon's secondary mouth was done in order to improve the water exchange between the lagoon and the sea and to reclaim the lagoon's floor. This intervention comprised reprofiling the submerged sandspit platform and the tidal channel and nourishing the barrier island. After completion of the intervention, clam production increased by 28% and the lagoon's ecological quality substantially improved. The project utilized some of the eight principles of integrated coastal zone management to reach the best compromise between the socioeconomic needs and preservation of the lagoon. The realization of the successful intervention was first secured in a memorandum of agreement that was drafted by negotiations between the Emilia-Romagna Region Council, the Province of Ferrara, Goro Municipality, and the local fishermen's association. Two committees managed the intervention and ensured that all stakeholders participated in the decisionmaking process. The collaboration between public and private sectors enabled the forging of a cost-effective intersectoral intervention with a long-term perspective, which fulfilled the specific ecological needs of the lagoon and guaranteed sustainable development for the lagoon's adjacent human communities.     

时变动载荷状况下高速列车对铁路桥振动的影响

研究了桥梁在高速列车定载荷和交变载荷作用下,桥梁挠度的变化情况.     

A comparison of rail liberalisation levels across four European countries

This paper presents the results of a research into railway regulation and liberalisation in Italy, France, Germany and Spain. The analysis covers the relationship between the State and the rail companies, network access conditions by operators, slot allocating and pricing schemes and how public service obligations are defined, financed and regulated.     

阻尼车轮噪声鉴定

铁路车轮阻尼被公认为是减少滚动噪声的可能措施之一.本文介绍了约束层阻尼车轮性能鉴定的试验方法和试验结果.     

西班牙、意大利高速铁路隧道与列控系统技术

西班牙和意大利高速铁路隧道施工管理严格,工艺细致,机械化程度高,安全事故少,施工质量好,其列控系统的发展方向是采用ETCS2,它一般用于高速新线建设,满足最高350km/h运行速度的控制,最小追踪间隔可达2.5min。通过借鉴和吸收两国高速铁路隧道与列控系统技术,在隧道勘察、结构和防排水设计等方面,改进隧道设计施工方法,更新设计理念、提升设计和施工技术水平,开展和推广隧道施工标准化作业程序;在列控系统的运用方面,要引进、消化、吸收和集成创新,研究面向提速线路和客运专线的CTCS2和CTCS3列控系统。