Prediction of interior noise of a small aircraft

The aim was to determine, already at the design stage, the interior noise level in a new small aircraft. The noise predictions were based on full-scale measurements on an existing model. A number of models for the prediction of velocity levels of a fuselage excited by turbulent boundary layers are discussed. Predicted results are compared to the result of in-flight measurements. It is found that the Corcos model gives the best agreement with the measured results. It is found that the velocity level of the plate elements of the fuselage very much depends on the speed of the aircraft. An increase of the speed by 10 % increases the plate velocity level by 3 dB. The velocity level is also strongly dependent on the plate thickness. An increase of the thickness by 50 % will decrease the velocity level by 5 dB. Small variations of other parameters like width and height and curvature of plate have only a very marginal effect on the plate velocity in the frequency range of interest. However, the acoustic power radiated into the aircraft cabin depends on the plate velocity of the fuselage as well the sound radiation properties of the plate structure. In the frequency, range of importance for the A-weighted noise level in the cabin the sound radiation ratio is increased as the plate thickness is increased. The noise level in the cabin is thus reduced much less than the velocity level of the fuselage by increasing the plate thickness. An increase of the width and length of plate elements reduces the sound intensity radiated by a plate. A combination of increased width and length and thickness of plate can result in a reduced noise radiation from the fuselage and thus in a reduced interior noise level.QC 20140102</p

Prediction of interior noise of a small aircraft

The aim was to determine, already at the design stage, the interior noise level in a new small aircraft. The noise predictions were based on full-scale measurements on an existing model. A number of models for the prediction of velocity levels of a fuselage excited by turbulent boundary layers are discussed. Predicted results are compared to the result of in-flight measurements. It is found that the Corcos model gives the best agreement with the measured results. It is found that the velocity level of the plate elements of the fuselage very much depends on the speed of the aircraft. An increase of the speed by 10 % increases the plate velocity level by 3 dB. The velocity level is also strongly dependent on the plate thickness. An increase of the thickness by 50 % will decrease the velocity level by 5 dB. Small variations of other parameters like width and height and curvature of plate have only a very marginal effect on the plate velocity in the frequency range of interest. However, the acoustic power radiated into the aircraft cabin depends on the plate velocity of the fuselage as well the sound radiation properties of the plate structure. In the frequency, range of importance for the A-weighted noise level in the cabin the sound radiation ratio is increased as the plate thickness is increased. The noise level in the cabin is thus reduced much less than the velocity level of the fuselage by increasing the plate thickness. An increase of the width and length of plate elements reduces the sound intensity radiated by a plate. A combination of increased width and length and thickness of plate can result in a reduced noise radiation from the fuselage and thus in a reduced interior noise level.QC 20140102</p

Construction and application of enhanced recovery after surgery‐optimized management system with nurse‐led multidisciplinary cooperation

Abstract Aim To evaluate the effect of enhanced recovery after surgery (ERAS)‐optimized management system with nurse‐led multidisciplinary cooperation. Design A quasi‐experimental design. Methods Nursing department cooperated with medical and clinical department to establish an ERAS‐optimized management system. After the system was developed, it was applied in surgical departments of the hospital. Using convenience sampling, 220 selective surgical patients, 82 nurses and 98 doctors from January 1st, 2021 to July 31st, 2021 were selected as the trial group. 220 selective surgical patients, 82 nurses and 98 doctors were selected as the control group from January 1st, 2020 to July 31st, 2020. ERAS observation indicators were compared between the two groups before and 6 months after implementation. The nurse professional identity scores and satisfaction of medical cooperation scores of the two groups at different time points were analysed by repeated analysis of variance. Results After the implementation, ERAS observation indicators in the trial group were better than the control group (p < 0.05). There were significant differences in the group main effect, time main effect and interaction effect of nurse professional identity scores, satisfaction of medical cooperation scores and scores in all dimensions between the two groups (p < 0.05). The scores of the experimental group at 3 months and 6 months after implementation were better than those of the control group (p < 0.05). Conclusions Enhanced recovery after surgery‐optimized management system with nurse‐led multidisciplinary cooperation was an effective working method. It could promote patients recovery and enhance nurse professional identity