Acoustic models of railway vehicles in standstill and pass-by conditions can be used as part of a virtual certification process for new trains.For each piece of auxiliary equipment,the sound power measured on a test b...Acoustic models of railway vehicles in standstill and pass-by conditions can be used as part of a virtual certification process for new trains.For each piece of auxiliary equipment,the sound power measured on a test bench is combined with meas-ured or predicted transfer functions.It is important,however,to allow for installation effects due to shielding by fairings or the train body.In the current work,fast-running analytical models are developed to determine these installation effects.The model for roof-mounted sources takes account of diffraction at the corner of the train body or fairing,using a barrier model.For equipment mounted under the train,the acoustic propagation from the sides of the source is based on free-field Green’s functions.The bottom surfaces are assumed to radiate initially into a cavity under the train,which is modelled with a simple diffuse field approach.The sound emitted from the gaps at the side of the cavity is then assumed to propagate to the receivers according to free-field Green’s functions.Results show good agreement with a 2.5D boundary element model and with measurements.Modelling uncertainty and parametric uncertainty are evaluated.The largest variability occurs due to the height and impedance of the ground,especially for a low receiver.This leads to standard deviations of up to 4 dB at low frequencies.For the roof-mounted sources,uncertainty over the location of the corner used in the equivalent barrier model can also lead to large standard deviations.展开更多
Shanghai Power Station Auxiliary Equipment Works (referred to as SDF) was established in April, 1980 on the base of the urban area previously owned by Shanghai Boiler Works so as to facilitate
This paper aims to improve the pre-hospital first-aid knowledge and pre-hospital first-aid success rate and optimize the pre-hospital emergency system.This paper mainly discusses a comprehensive pre-hospital emergency...This paper aims to improve the pre-hospital first-aid knowledge and pre-hospital first-aid success rate and optimize the pre-hospital emergency system.This paper mainly discusses a comprehensive pre-hospital emergency system,which consists of the hardware part and software part.The hardware is based on the international cardiopulmonary resuscitation guidelines,and a cardiopulmonary resuscitation(CPR)training auxiliary equipment is developed,which can be applied in pre-hospital first aid training to help people perform accurate chest compressions.The software part is based on the WeChat applet platform to set up a pre-hospital first-aid dispatching system that connects callers and CPR rescuers.The software system effectively improves the pre-hospital CPR first-aid system and increases the rescue success rate of cardiac arrest patients.展开更多
基金The work described here has been supported by the TRANSIT project(funded by EU Horizon 2020 and the Europe’s Rail Joint Undertaking under grant agreement 881771).
文摘Acoustic models of railway vehicles in standstill and pass-by conditions can be used as part of a virtual certification process for new trains.For each piece of auxiliary equipment,the sound power measured on a test bench is combined with meas-ured or predicted transfer functions.It is important,however,to allow for installation effects due to shielding by fairings or the train body.In the current work,fast-running analytical models are developed to determine these installation effects.The model for roof-mounted sources takes account of diffraction at the corner of the train body or fairing,using a barrier model.For equipment mounted under the train,the acoustic propagation from the sides of the source is based on free-field Green’s functions.The bottom surfaces are assumed to radiate initially into a cavity under the train,which is modelled with a simple diffuse field approach.The sound emitted from the gaps at the side of the cavity is then assumed to propagate to the receivers according to free-field Green’s functions.Results show good agreement with a 2.5D boundary element model and with measurements.Modelling uncertainty and parametric uncertainty are evaluated.The largest variability occurs due to the height and impedance of the ground,especially for a low receiver.This leads to standard deviations of up to 4 dB at low frequencies.For the roof-mounted sources,uncertainty over the location of the corner used in the equivalent barrier model can also lead to large standard deviations.
文摘Shanghai Power Station Auxiliary Equipment Works (referred to as SDF) was established in April, 1980 on the base of the urban area previously owned by Shanghai Boiler Works so as to facilitate
基金Natural Science Foundation of Guangdong Province,grant number:2016KZDXM013
文摘This paper aims to improve the pre-hospital first-aid knowledge and pre-hospital first-aid success rate and optimize the pre-hospital emergency system.This paper mainly discusses a comprehensive pre-hospital emergency system,which consists of the hardware part and software part.The hardware is based on the international cardiopulmonary resuscitation guidelines,and a cardiopulmonary resuscitation(CPR)training auxiliary equipment is developed,which can be applied in pre-hospital first aid training to help people perform accurate chest compressions.The software part is based on the WeChat applet platform to set up a pre-hospital first-aid dispatching system that connects callers and CPR rescuers.The software system effectively improves the pre-hospital CPR first-aid system and increases the rescue success rate of cardiac arrest patients.
