目的:对急诊重症监护病房(EICU)的噪音水平进行调查分析,查找噪音分布的主要时段及来源,为制定有效的措施提供依据。方法:参考世界卫生组织(WHO)建议的关于医院平均噪音水平,运用声音强度监测仪(SW-525B分贝仪)监测各时段EICU噪音水平...目的:对急诊重症监护病房(EICU)的噪音水平进行调查分析,查找噪音分布的主要时段及来源,为制定有效的措施提供依据。方法:参考世界卫生组织(WHO)建议的关于医院平均噪音水平,运用声音强度监测仪(SW-525B分贝仪)监测各时段EICU噪音水平并记录,分析噪音来源。结果:EICU监测到的噪音平均值为:日间噪音平均值46.7~67.3 d B,夜间噪音平均值38.7~52.4 d B。噪音主要来源于仪器设备报警声、医护人员日常操作、医护沟通、家属探视交谈及周围环境噪音。结论:EICU噪音水平远超过WHO建议水平,制定降低噪音的措施刻不容缓。展开更多
A multi-dimensional computational fluid dynamics(CFD) approach was proposed in this study aiming to calculate the transfer matrix of an engine exhaust muffler in the conditions with and without mean flow.The CFD model...A multi-dimensional computational fluid dynamics(CFD) approach was proposed in this study aiming to calculate the transfer matrix of an engine exhaust muffler in the conditions with and without mean flow.The CFD model of the muffler with absorptive material defined as porous zone was calibrated with the measured noise reduction without mean flow,and was further employed to study the effect of the mean flow on the acoustic performance of the muffler.Furthermore,the exhaust acoustical source was derived from the calculated transfer matrices of six different additional acoustic loads obtained by the proposed CFD approach as well as the measured tail noise based on a multiload least squares method.Finally,the exhaust noise was predicted based on Thevenin's theorem.The proposed CFD approach was suggested to be able to predict the acoustic performance of a complex muffler considering mean flow(without and with mean flow) and heat transfer,and provide reasonable results of the exhaust noise.展开更多
文摘目的:对急诊重症监护病房(EICU)的噪音水平进行调查分析,查找噪音分布的主要时段及来源,为制定有效的措施提供依据。方法:参考世界卫生组织(WHO)建议的关于医院平均噪音水平,运用声音强度监测仪(SW-525B分贝仪)监测各时段EICU噪音水平并记录,分析噪音来源。结果:EICU监测到的噪音平均值为:日间噪音平均值46.7~67.3 d B,夜间噪音平均值38.7~52.4 d B。噪音主要来源于仪器设备报警声、医护人员日常操作、医护沟通、家属探视交谈及周围环境噪音。结论:EICU噪音水平远超过WHO建议水平,制定降低噪音的措施刻不容缓。
文摘A multi-dimensional computational fluid dynamics(CFD) approach was proposed in this study aiming to calculate the transfer matrix of an engine exhaust muffler in the conditions with and without mean flow.The CFD model of the muffler with absorptive material defined as porous zone was calibrated with the measured noise reduction without mean flow,and was further employed to study the effect of the mean flow on the acoustic performance of the muffler.Furthermore,the exhaust acoustical source was derived from the calculated transfer matrices of six different additional acoustic loads obtained by the proposed CFD approach as well as the measured tail noise based on a multiload least squares method.Finally,the exhaust noise was predicted based on Thevenin's theorem.The proposed CFD approach was suggested to be able to predict the acoustic performance of a complex muffler considering mean flow(without and with mean flow) and heat transfer,and provide reasonable results of the exhaust noise.
