Development of a methodology for studying tunnel climate in long railway tunnels and for optimizing the design process of cross-passage cooling systems

When it comes into operation in 2026, the Koralmtunnel in Austria will be the world́s seventh longest railway tunnel. The installation of the power supply, telecommunications and electro-mechanical services is currently ongoing. Parts of these systems have to be protected from temperature and humidity variations and from the high dust loads which are characteristic of the tunnel atmosphere. In particular, cooling systems are required to counteract the significant amounts of heat released by some installations. Information on a large number of parameters (e.g. tunnel air temperatures) is required in the design process. However, such information is only partly available in the design stage. Hence, a prediction of tunnel air temperatures has to be made. Additionally, since hardly any information about the tunnel climate in long railway tunnels is available and in-situ mea- surements are not possible, as thermal conditions differ significantly between the construction/equipping phase and the operation phase, a novel methodology for the prediction of the tunnel climate had to be developed. This article presents a description of a new method comprising four main investigative steps and of its application to the Koralmtunnel as a selected case study. While steps 1 and 2 provide information about the actual cooling requirement and tunnel air temperatures for a period of 50 years, steps three and four of the investigation aim at the technical and economic optimization of cooling systems

Emissions from railways: Results of tests on a pantograph-catenary test bench

Many railway tracks have been electrified, thus eliminating exhaust emissions. However, railways still emit particles due to abrasion and wear. The main such particle sources are brakes, wheel-rail contact, and pantographs and contact wire. However, information on the quantities of such particles is rare. Estimations in published data are quite heterogeneous, with PM10 emission levels varying by a factor of ten. In an attempt to improve the database and to reduce uncertainties, a series of test bench tests was conducted on pantograph-catenary contact. In order to study the impact of specific parameters, i.e. of train speed, contact force and current intensity, on the emitted particle mass and size distribution, parameter levels were varied across the tests. A chemical analysis of emitted particles provided information on the respective contributions of contact strip and contact wire. PM10 emission factors were found to lie in the range of 0.14–0.62 g/km

Data Hiding Techniques for Database Environments

Part 6: ADVANCED FORENSIC TECHNIQUESInternational audienceDatabases are widely used today, but the study of forensic analysis in database environments has not been extensive. The lack of research is due mostly to the complex structure of databases and the scarcity of database forensic tools. This has created a wide range of possibilities for data hiding as a means to hinder data discovery during forensic investigations. This paper describes several techniques that can be used to hide data in a database. Although the techniques are evaluated with respect to object-relational databases, they can be applied to any type of database