| 1. |
- Maier, Hannes, et al.
(författare)
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Consensus Statement on Bone Conduction Devices and Active Middle Ear Implants in Conductive and Mixed Hearing Loss
- 2022
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Ingår i: Otology and Neurotology. - : Lippincott, Williams & Wilkins. - 1531-7129 .- 1537-4505. ; 43:5, s. 513-529
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Tidskriftsartikel (refereegranskat)abstract
- Nowadays, several options are available to treat patients with conductive or mixed hearing loss. Whenever surgical intervention is not possible or contra-indicated, and amplification by a conventional hearing device (e.g., behind-the-ear device) is not feasible, then implantable hearing devices are an indispensable next option. Implantable bone-conduction devices and middle-ear implants have advantages but also limitations concerning complexity/invasiveness of the surgery, medical complications, and effectiveness. To counsel the patient, the clinician should have a good overview of the options with regard to safety and reliability as well as unequivocal technical performance data. The present consensus document is the outcome of an extensive iterative process including ENT specialists, audiologists, health-policy scientists, and representatives/technicians of the main companies in this field. This document should provide a first framework for procedures and technical characterization to enhance effective communication between these stakeholders, improving health care.
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| 2. |
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| 3. |
- Petrachenko, Bill, et al.
(författare)
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Design Aspects of the VLBI2010 System
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This report summarizes the progress made in developing the next generation VLBI, dubberd the VLBI2010 system. The VLBI2010 Committee of the International Service for Geodesy and Astrometry (IVS) worked on the design aspects of the new system.…
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| 4. |
- Petrachenko, Bill, et al.
(författare)
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Progress Report of the IVS VLBI2010 Committee
- 2009
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Ingår i: In: International VLBI Service for Geodesy and Astrometry 2008 Annual Report, edited by D. Behrend and K. Baver. ; NASA/TP-2009-214183, 2009, s. 13-67
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Thomas, Dirk, 1978-, et al.
(författare)
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Dynamics of a high-speed rail vehicle negotiating curves at unsteady crosswind
- 2010
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Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - London : Professional Engineering Publishing. - 0954-4097 .- 2041-3017. ; 224:F6, s. 567-579
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Tidskriftsartikel (refereegranskat)abstract
- Rail vehicles in everyday operation experience large lateral influences from curves and track imperfections, yielding large suspension deflections and displacements of the carbody relative to the track. Aerodynamic loads caused by crosswind may deteriorate the conditions that can result in vehicle overturning. This study investigates the influence of crosswind on a highspeed rail vehicle negotiating a curve. A multi-body simulation model of a high-speed rail vehicle is subjected to unsteady aerodynamic loads. The vehicle response is studied for different gusts, and variations of some vehicle parameters are performed.
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| 6. |
- Thomas, Dirk, 1978-, et al.
(författare)
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Improving crosswind stability of fast rail vehicles using active secondary suspension
- 2014
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Ingår i: Vehicle System Dynamics. - : Informa UK Limited. - 0042-3114 .- 1744-5159. ; 52:7, s. 909-921
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Tidskriftsartikel (refereegranskat)abstract
- Rail vehicles are today increasingly equipped with active suspension systems for ride comfort purposes. In this paper, it is studied whether these often powerful systems also can be used to improve crosswind stability. A fast rail vehicle equipped with active secondary suspension for ride comfort purposes is exposed to crosswind loads during curve negotiation. For high crosswind loads, the active secondary suspension is used to reduce the impact of crosswind on the vehicle. The control input is taken from the primary vertical suspension deflection. Three different control cases are studied and compared with the only comfort-oriented active secondary suspension and a passive secondary suspension. The application of active secondary suspension resulted in significantly improved crosswind stability.
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| 7. |
- Thomas, Dirk, 1978-
(författare)
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Lateral Stability of High-Speed Trains at Unsteady Crosswind
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Crosswind stability of rail vehicles has been a research area for several decades,mainly motivated by vehicle overturning accidents and higher speeds, but in recenttimes also by issues of lower energy consumption and track maintenance costsdemanding lower vehicle weights. During everyday operation, rail vehicles are subjectedto large lateral influences from track irregularities, track curves and crosswind,leading to large suspension deflections and increased crosswind sensitivity.Also unsteady crosswind like gusts calls for attention. Simulations of possible vehicleoverturning are necessary, but need to take large deflections and high shear inthe suspension into account. If delivering reasonable results, simulations representan important tool for overturning prediction of the vehicle. In the present work, multibody simulations of a high-speed vehicle at large lateralinfluences from track curves and track irregularities have been carried out, using ahalf-vehicle model in 2D and a model of a whole vehicle in 3D. The vehicle modelsalso include different suspension models. Corresponding field measurements ofthe relative lateral and vertical deflections in the secondary suspension have beenperformed on a fast train and used for validation of the multibody simulations,resulting in good agreement between measurements and simulations. The 3D vehicle model was further used to study the vehicle response to unsteadycrosswind during curve negotiation where aerodynamic loads obtained by unsteadyComputational Fluid Dynamics, namely Detached Eddy Simulations, representingthree types of gusts were used. In addition, the method of Quasi Transient GustModelling was evaluated in terms of overturning risk. Strong lateral and roll responsesof the vehicle and influences of the gust duration and the relative differencebetween mean and maximum wind speed were observed. Further, variations of suspensionand mass properties of the vehicle were performed to study the influenceon crosswind sensitivity. The position of the centre of mass of the carbody and thelateral bumpstop clearance showed significant influence on the crosswind stability.
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| 8. |
- Thomas, Dirk, 1978-, et al.
(författare)
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Measurements and simulations of rail vehicle dynamics with respect to overturning risk
- 2010
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Ingår i: Vehicle System Dynamics. - Milton Park : Taylor & Francis. - 0042-3114 .- 1744-5159. ; 48:1, s. 97-112
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Tidskriftsartikel (refereegranskat)abstract
- Rail vehicles are exposed to strong lateral influences through curves, track imperfections andcrosswind leading to large deflections of the vehicle suspension systems and carbody displacements.In turn this increases the risk of vehicle overturning. In the present work multibodysimulations are performed in order to study the motion in the secondary suspension. Suspensiondeflection measurements on a fast test train were carried out and used for validation ofthe simulations. The simulations show good agreement with the measurements and representa good tool to predict the motion in the secondary suspension.
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| 9. |
- Thomas, Dirk, 1978-
(författare)
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On Rail Vehicle Dynamics in Unsteady Crosswind Conditions : Studies Related to Modelling, Model Validation and Active Suspension
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Crosswind stability of rail vehicles has been a research area for several decades, mainlymotivated by vehicle overturning accidents and higher speeds, but in recent times also byissues of lower energy consumption and track maintenance costs demanding lower vehi-cle weights. During everyday operation, rail vehicles are subjected to substantial lateralinfluences from track curves, track irregularities and crosswind, leading to large suspen-sion deflections and increased crosswind sensitivity. Unsteady crosswind like gusts alsocalls for attention. Simulations of possible vehicle overturning are necessary, but needto take large deflections and high shear in the suspension into account. If they deliverreasonable results, simulations represent an important tool for overturning predictionof rail vehicles.In the present work, multibody simulations of a high-speed rail vehicle under large lat-eral influences from track curves and track irregularities have been carried out, using ahalf-vehicle model in 2D and a full vehicle model in 3D, including different suspensionmodels. Corresponding field measurements of the relative lateral and vertical deflec-tions in the secondary suspension were performed on a fast train and used to validatethe multibody simulations.The 3D vehicle model was further used to study the vehicle response to unsteady cross-wind during curve negotiation, including aerodynamic loads obtained from unsteadyComputational Fluid Dynamics. In addition, the Quasi Transient Gust Modelling methodwas evaluated. Strong lateral and roll responses of the vehicle and influences of the gustduration and the relative difference between mean and maximum wind speed were ob-served. The influence of the vehicle’s suspension and mass properties on crosswindsensitivity were studied in addition.In order to validate modelling and simulation results for gust-like loads on a rail vehi-cle, full-scale experiments were conducted by exciting the carbody of a stationary railvehicle, imitating synchronous and asynchronous crosswind-like loads and measuringthe vehicle response. The measurements were reflected in multibody simulations, whichwere in good agreement with the measured responses. Parameter studies of the suspen-sion characteristics were performed additionally. Asynchronous crosswind-like loadswere in comparison to synchronous loads observed to result in lower wheel-unloadingIt was further studied whether active secondary suspension can be used to improve cross-wind stability. A fast rail vehicle equipped with active secondary suspension for ridecomfort purposes is exposed to crosswind loads during curve negotiation by means ofsimulations. For high crosswind loads, the active suspension is used to reduce the impactof crosswind on the vehicle. The control input is taken from the primary vertical sus-pension deflection. Three different control cases were studied and compared to the onlycomfort-oriented active secondary suspension and a passive secondary suspension. The application of active suspension resulted in significantly improved crosswind stability.
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| 10. |
- Thomas, Dirk, 1978-, et al.
(författare)
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Rail vehicle response to lateral carbody excitations imitating crosswind
- 2015
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Ingår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit. - : SAGE Publications. - 0954-4097 .- 2041-3017. ; 229:1, s. 34-47
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Tidskriftsartikel (refereegranskat)abstract
- Repeatable field tests to measure the vehicle response to unsteady crosswinds are not practical due to safety and economic reasons. Simulations are therefore necessary to gather information on the vehicle response to crosswind. However, in turn, these simulations need to be validated. This study presents results of measured quasi-static and dynamic responses of a stationary rail vehicle due to defined lateral carbody excitations imitating unsteady crosswind, which are reflected by multibody simulations. The vehicle responses are measured in terms of suspension deflections, lateral carbody accelerations and vertical wheel/rail forces. The vehicle dynamic response to a gust-like event results in an overshoot of wheel unloading. In general the measurements and simulations show good agreement. However, the simulations partly overestimate the responses slightly and an influence due to airspring levelling can be observed in the measured values of quasi-static load cases.
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