Track loading limits and cross-acceptance of vehicle approvals

The requirements for track loading limits are one of the main barriers to simple cross-acceptance of vehicles where rolling stock that is already operating successfully in one (or more) networks has to be retested before it can be approved for operation on another network. DynoTRAIN Work Package 4 studied this area in order to determine whether the additional requirements were justified, or if the process could be made much cheaper and simpler without increasing the risk of track deterioration for the networks. The review of national requirements identified modified criteria and limit values for track forces in some member states; however, these can be obtained from additional analysis of the normal test results with no new tests required. The influence of design rail inclination has also been found not to be significant, provided a realistic range of wheel–rail contact conditions are included in the tests. For line speeds greater than or equal to 160 km/h, the current standards for track construction across the member states appear to be similar. On lower speed lines in some countries, a ‘weaker’ track condition may require a lower limit on one of the vehicle assessment parameters. Track dynamics modelling has shown that the vehicle assessment parameters used in international standards are suitable for use in cross-acceptance for track forces. The use of multiple regression analysis allows the estimated maximum value for relevant parameters to be evaluated for different target conditions and then compared with the appropriate limit value, or with values for existing, comparable vehicles. Guidance has also been provided on the relevant parameters to consider when developing operating controls for different types of track deterioration

Cloning and characterization of the genomic DNA of the human MSSP genes.

MSSP proteins have been identified by their binding to an upstream element of c-myc. Independently, two different approaches yielded two cDNA clones highly homologous to the MSSP cDNAs, suggesting an involvement of MSSP in the regulation of the cell cycle (scr2) and in the repression of HIV-1 and ILR2 alpha-promoter transcription (human YC1). Screening human genomic libraries, we have isolated clones belonging to two different gene loci. Whereas the human MSSP gene 1 turned out to be intronless, the organization of the coding sequence within gene 2 is more complex. It spans more than 60 kb and contains 16 exons (including two alternative first exons), ranging from 48 to 287 bp, respectively. The intron sizes vary from 0.1 to more than 13 kb. Gene 1 has been completely sequenced. A deletion series of its upstream region was conjugated to the luciferase gene, but the transfection of the constructs did not display any promoter activity. Moreover, compared with gene 2 and the cDNA sequences known so far, about 20 point mutations as well as flanking direct repeats have been detected in the MSSP gene 1, showing that it possesses all the characteristics of processed retropseudogenes. Sequence analysis of a 1.7 kb fragment of the 5' flanking region of the MSSP gene 2 revealed that the promoter of gene 2 lacks consensus sequences for TATA and CCAAT boxes, is GC-rich, and contains numerous potential transcription factor binding elements including an Sp1 binding site. DNase I footprinting experiments showed that the putative Sp1 site was bound by proteins. The results of primer extension and S1 mapping analyses suggested the transcription of the gene starts at multiple positions upstream from the initiator methionine codon. Luciferase assays employing progressive deletions of the 1.7 kb promoter region allowed us to define the minimal promoter region of 428 bp (-488/+) and revealed a complex pattern of the transcriptional regulation the human MSSP gene 2. Furthermore, it can be concluded that the MSSP gene 2 encodes both MSSP-1 and MSSP-2, and moreover scr2 and human YC1

A time-resolved particle image velocimetry investigation of a cavity flow with a thick incoming turbulent boundary layer

The present paper aims for a better understanding of the flow in a rectangular cavity at very low Mach number and with a thick incoming turbulent boundary layer. In the present experiment the boundary layer is defined as thick because the ratio of the cavity length to the momentum thickness Θ is low (L/Θ = 18) with respect to the claimed threshold (L/Θ>80) for cavity self-sustained oscillations to take place. Time-resolved particle image velocimetry (PIV) measurements were taken in planes normal and parallel to the wall over a cavity having aspect ratio L/H = 4, at ReΘ = 1041. The PIV data were analyzed to give the mean characteristics and the time behavior of the flow. The irregular vortex shedding observed in the shear layer was analyzed and interpreted with reference to the coherent structures in the incoming turbulent boundary layer. The unsteady load on the cavity walls and the consequent oscillating drag forces were studied by analyzing the instant momentum flux across the cavity mouth. A low frequency mode of about 2 Hz, corresponding to a Strouhal number based on the cavity length of StL = 0.2, was revealed. This oscillation mode is due to the build up of the flow inside the cavity and not to the vortex shedding in the shear laye

The DLR_School_Lab Oberpfaffenhofen - a science lab to attract young people to science and engineering

The DLR_School_Lab Oberpfaffenhofen is a typical extracurricular science lab, its main objective being to attract secondary school students to science and technology. It has been developed and operated since 2003 by the German Aerospace Center DLR, Germany's national research centre for aeronautics and space as well as Germany's space agency. For this purpose, each of the eight DLR institutes at the Oberpfaffenhofen research site has designed experiments which are, on one hand, based on its respective core research areas and which, on the other hand, are suitable for secondary school students (age 14 to 18). In total, the School_Lab offers a total of 12 experiments in the research areas of • earth observation sensor technologies (visible, infrared, radar, and lidar) • processing and analysis of earth observation data • environmental research • meteorology • communication and navigation • robotics and mechanical simulation The scientific concept behind each of the experiments includes the involvement of scientific and technical experts, a combination of specialist know-how and high-tech equipment (hardware and software), continuous updating and permanent development of the experiments, and close relation to state-of-the-art research. The didactic concept for each experiment is based on small experimental groups (four students and one supervising student), emphasizing autonomous and haptical work, in a time frame of two hours per experiment. This approach is a straightforward application of the concept of IBSE (inquiry-based science education, as proposed by the European Commission ), allowing the level of complexity to be adjusted to each individual group, with the results depending on the students’ ages and capabilities. In its regular operation the experiments are open to secondary level school classes with up to 30 students. The visiting classes usually stay for one day, each student performs two different experiments. To date, more than 5,500 students have visited the DLR_School_Lab Oberpfaffenhofen. The second important activity of the DLR_School_Lab Oberpfaffenhofen is teacher education. Physics and natural science teachers are invited to learn about the science lab’s concept by an overview lectures, by science lessons about the ongoing research at the institutes, by performing the DLR_School_Lab experiments. Additionally, teachers are provided with written material about the science and didactics of the experiments. This facilitates to incorporate the experiments into their standard curricula and school education process and, thereby, helps to guarantee a sustainable effect of the students’ visits to the DLR_School_Lab. Close to 1.000 teachers have already been educated, the respective groups coming from individual secondary schools, or in the frame of regional teacher education seminars organised by the regional school authorities. The highest multiplication effect is achieved by educating seminar teacher (i.e. teachers educating the new teachers), up to date initiated three times by the Bavarian Teacher Education Academy. Altogether, the concept of the DLR_School_Lab is an excellent paradigm for a Research and Education Cooperation, the corresponding concept is well worth while being adopted by other similar research organisations in Europe