33 research outputs found
Railway-induced ground vibrations – a review of vehicle effects
This paper is a review of the effect of vehicle characteristics on ground- and track borne-vibrations from railways. It combines traditional theory with modern thinking and uses a range of numerical analysis and experimental results to provide a broad analysis of the subject area. First, the effect of different train types on vibration propagation is investigated. Then, despite not being the focus of this work, numerical approaches to vibration propagation modelling within the track and soil are briefly touched upon. Next an in-depth discussion is presented related to the evolution of numerical models, with analysis of the suitability of various modelling approaches for analysing vehicle effects. The differences between quasi-static and dynamic characteristics are also discussed with insights into defects such as wheel/rail irregularities. Additionally, as an appendix, a modest database of train types are presented along with detailed information related to their physical attributes. It is hoped that this information may provide assistance to future researchers attempting to simulate railway vehicle vibrations. It is concluded that train type and the contact conditions at the wheel/rail interface can be influential in the generation of vibration. Therefore, where possible, when using numerical approach, the vehicle should be modelled in detail. Additionally, it was found that there are a wide variety of modelling approaches capable of simulating train types effects. If non-linear behaviour needs to be included in the model, then time domain simulations are preferable, however if the system can be assumed linear then frequency domain simulations are suitable due to their reduced computational demand
Recommended from our members
Northern Eurasia Future Initiative (NEFI): facing the challenges and pathways of global change in the 21st century
During the past several decades, the Earth system has changed significantly, especially across Northern Eurasia. Changes in the socio-economic conditions of the larger countries in the region have also resulted in a variety of regional environmental changes that can
have global consequences. The Northern Eurasia Future Initiative (NEFI) has been designed as an essential continuation of the Northern Eurasia Earth Science
Partnership Initiative (NEESPI), which was launched in 2004. NEESPI sought to elucidate all aspects of ongoing environmental change, to inform societies and, thus, to
better prepare societies for future developments. A key principle of NEFI is that these developments must now be secured through science-based strategies co-designed
with regional decision makers to lead their societies to prosperity in the face of environmental and institutional challenges. NEESPI scientific research, data, and
models have created a solid knowledge base to support the NEFI program. This paper presents the NEFI research vision consensus based on that knowledge. It provides the reader with samples of recent accomplishments in regional studies and formulates new NEFI science questions. To address these questions, nine research foci are identified and their selections are briefly justified. These foci include: warming of the Arctic; changing frequency, pattern, and intensity of extreme and inclement environmental conditions; retreat of the cryosphere; changes in terrestrial water cycles; changes in the biosphere; pressures on land-use; changes in infrastructure; societal actions in response to environmental change; and quantification of Northern Eurasia's role in the global Earth system. Powerful feedbacks between the Earth and human systems in Northern Eurasia (e.g., mega-fires, droughts, depletion of the cryosphere essential for water supply, retreat of sea ice) result from past and current human activities (e.g., large scale water withdrawals, land use and governance change) and
potentially restrict or provide new opportunities for future human activities. Therefore, we propose that Integrated Assessment Models are needed as the final stage of global
change assessment. The overarching goal of this NEFI modeling effort will enable evaluation of economic decisions in response to changing environmental conditions and justification of mitigation and adaptation efforts
New temperate Pseudomonas aeruginosa phage, phi297: Specific features of genome structure
Pharmacy Practice in the Prostějov Region during the Health Care Development Process after the 1989
Pharmacy Practice in the Prostějov Region during the Health Care Development Process after the 1989 Student: Eva Navrátilová Tutor: Doc. PhDr. František Dohnal, CSc. Social and Clinical Pharmacy Department Pharmaceutical Faculty in Hradec Králové The Charles University in Prague, Czech Republic Theme: Pharmacy Practice in the Prostějov Region during the Health Care Development Process after the 1989 Objective: Survey of the history of pharmacies and pharmacists in the Prostějov Region after the 1989 during the health care development process. Methods: Excerption of the availability literature, processing the regional newspapers that were obtained from the Town library in Prostějov and Town archive in Prostějov, the questionnaires, the materials of the district corporation of the pharmacists and interviews with the local pharmacy keepers. Results: Before 1989 in the Prostějov Region there were 12 pharmacies, 6 in the region and 6 in the city of Prostějov. After the 1989 many new pharmacies were established. Some pharmacies have established the OOVL (a small pharmacy by their "mother pharmacy"), their expansion have begun after the 1998. In the city of Prostějov we can find the pharmacies in the supermarkets too. Some historical pharmacies and some new have disappeared because of their competition. In..