Experimental and numerical studies of acoustical and ventilation performances of glass louver window

The noise attenuation and ventilation performances of the glass louver window were investigated using experimental and numerical methods in order to improve the understanding of this common feature in noise mitigation issue. Sound pressure levels (SPLs) data were measured for frequencies ranging from 100 Hz to 6000 Hz for a room fitted with a louver window. It was found that the louver window was able to attenuate 1.4 %, 5.5 % and 12.0 % of the noise when the panels were partially and fully closed at 30°, 60° and 90°, respectively. For frequencies below 3000 Hz, the best attenuation occurred around 1700 Hz to 2000 Hz for all panel angles. The insertion loss (IL) is similar for frequencies ranging from 3000 Hz to 6000 Hz when the louver window was fully closed at 90°. The velocity magnitude of the air passed through the louver panels increased with increased panel angle. The reduction of the mass flow rate for air passed through the louver window when the panels were partially closed at 30° and 60° are 7.7 % and 46.2 %, respectively

Experimental and numerical studies on the design of a sonic crystal window

Four sets of numerical models were created to study the effects of shapes, staggering patterns, Helmholtz resonators and array configurations on the acoustical performance of sonic crystals (SCs) in order to design an efficient SC window to mitigate the traffic noise level at a room in a student hostel of NUS. Rectangular SCs consistently obtained highest transmission loss for frequencies ranging from 300 Hz to 3000 Hz compared to diamond and semi-circle SCs. Fully staggered pattern performed better than non-staggered and 50 % staggered patterns for frequencies below 1700 Hz. Helmholtz resonators were useful for enhancing low frequency noise mitigation. The prototype of the final designed SC window was fabricated and tested in order to validate the simulation result. Generally, numerical and experimental results were in similar trends. Maximum transmission loss of the SC window was found to be occurred at 900 Hz which was about 18 dB

Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)

Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic

To which world regions does the valence–dominance model of social perception apply?

Over the past 10 years, Oosterhof and Todorov’s valence–dominance model has emerged as the most prominent account of how people evaluate faces on social dimensions. In this model, two dimensions (valence and dominance) underpin social judgements of faces. Because this model has primarily been developed and tested in Western regions, it is unclear whether these findings apply to other regions. We addressed this question by replicating Oosterhof and Todorov’s methodology across 11 world regions, 41 countries and 11,570 participants. When we used Oosterhof and Todorov’s original analysis strategy, the valence–dominance model generalized across regions. When we used an alternative methodology to allow for correlated dimensions, we observed much less generalization. Collectively, these results suggest that, while the valence–dominance model generalizes very well across regions when dimensions are forced to be orthogonal, regional differences are revealed when we use different extraction methods and correlate and rotate the dimension reduction solution

To which world regions does the valence–dominance model of social perception apply?

Over the past 10 years, Oosterhof and Todorov’s valence–dominance model has emerged as the most prominent account of how people evaluate faces on social dimensions. In this model, two dimensions (valence and dominance) underpin social judgements of faces. Because this model has primarily been developed and tested in Western regions, it is unclear whether these findings apply to other regions. We addressed this question by replicating Oosterhof and Todorov’s methodology across 11 world regions, 41 countries and 11,570 participants. When we used Oosterhof and Todorov’s original analysis strategy, the valence–dominance model generalized across regions. When we used an alternative methodology to allow for correlated dimensions, we observed much less generalization. Collectively, these results suggest that, while the valence–dominance model generalizes very well across regions when dimensions are forced to be orthogonal, regional differences are revealed when we use different extraction methods and correlate and rotate the dimension reduction solution.C.L. was supported by the Vienna Science and Technology Fund (WWTF VRG13-007); L.M.D. was supported by ERC 647910 (KINSHIP); D.I.B. and N.I. received funding from CONICET, Argentina; L.K., F.K. and Á. Putz were supported by the European Social Fund (EFOP-3.6.1.-16-2016-00004; ‘Comprehensive Development for Implementing Smart Specialization Strategies at the University of Pécs’). K.U. and E. Vergauwe were supported by a grant from the Swiss National Science Foundation (PZ00P1_154911 to E. Vergauwe). T.G. is supported by the Social Sciences and Humanities Research Council of Canada (SSHRC). M.A.V. was supported by grants 2016-T1/SOC-1395 (Comunidad de Madrid) and PSI2017-85159-P (AEI/FEDER UE). K.B. was supported by a grant from the National Science Centre, Poland (number 2015/19/D/HS6/00641). J. Bonick and J.W.L. were supported by the Joep Lange Institute. G.B. was supported by the Slovak Research and Development Agency (APVV-17-0418). H.I.J. and E.S. were supported by a French National Research Agency ‘Investissements d’Avenir’ programme grant (ANR-15-IDEX-02). T.D.G. was supported by an Australian Government Research Training Program Scholarship. The Raipur Group is thankful to: (1) the University Grants Commission, New Delhi, India for the research grants received through its SAP-DRS (Phase-III) scheme sanctioned to the School of Studies in Life Science; and (2) the Center for Translational Chronobiology at the School of Studies in Life Science, PRSU, Raipur, India for providing logistical support. K. Ask was supported by a small grant from the Department of Psychology, University of Gothenburg. Y.Q. was supported by grants from the Beijing Natural Science Foundation (5184035) and CAS Key Laboratory of Behavioral Science, Institute of Psychology. N.A.C. was supported by the National Science Foundation Graduate Research Fellowship (R010138018). We acknowledge the following research assistants: J. Muriithi and J. Ngugi (United States International University Africa); E. Adamo, D. Cafaro, V. Ciambrone, F. Dolce and E. Tolomeo (Magna Græcia University of Catanzaro); E. De Stefano (University of Padova); S. A. Escobar Abadia (University of Lincoln); L. E. Grimstad (Norwegian School of Economics (NHH)); L. C. Zamora (Franklin and Marshall College); R. E. Liang and R. C. Lo (Universiti Tunku Abdul Rahman); A. Short and L. Allen (Massey University, New Zealand), A. Ateş, E. Güneş and S. Can Özdemir (Boğaziçi University); I. Pedersen and T. Roos (Åbo Akademi University); N. Paetz (Escuela de Comunicación Mónica Herrera); J. Green (University of Gothenburg); M. Krainz (University of Vienna, Austria); and B. Todorova (University of Vienna, Austria). The funders had no role in study design, data collection and analysis, decision to publish or preparation of the manuscript.https://www.nature.com/nathumbehav/am2023BiochemistryGeneticsMicrobiology and Plant Patholog

A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic.

The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world

Experimental studies of stall delay on the blade of horizontal axis wind turbine

This study is to experimentally investigate the physics of stall delay phenomenon using a down-scaled model of the blade of a 5kW small-scale horizontal axis wind turbine (HAWT) which is designed here using the popular Blade Element Momentum (BEM) method. The design tip speed ratio (TSR) is 6. At the beginning, a wind tunnel tests were carried out to obtain the lift ( Ct) and drag ( Cd) coefficients of the S805 airfoil. The C1 and Cd were corrected under wind tunnel experimental condition. The effects of wind tunnel correction on C1 and Cd are not significant at low angles of attack (AOAs) and the effects increase with the increasing of AOA. With the C1 and Cd obtained, BEM method was used to design the 5kW wind turbine. Volumetric velocity fields are measured using Tomographic Particle Image Velocimetry (Tomo-PIV) on the 1:10 down-scaled model of the rotating blade at two different global TSR of 3 and 5 with Reynolds number (Re) of 4800 and 4300, respectively. Static pressures are also measured and results illustrate higher suction peaks on the rotating blade than those on the static airfoil, which is typically observed for stall delay. Rather than the recirculation bubbles with strong reversed flows for the static airfoil at stall, attached flows are observed on the suction surface of the rotating blade. Radial flows from rotating blade's root to tip are also found with strong spanwise velocity component located in the vicinities of the vortices and close to the rotating blade's suction surface. In contrast to the case of static airfoil, the vortices that shed from the rotating blade's edges are not found to break down into small pieces. Surface streamlines of rotating blade are also presented. At large AOAs, Coriolis forces are found to be larger than centrifugal forces in vertical direction in all three measurement volumes, which contributes to the reduction of the adverse pressure gradient. In addition, the effects of freestream turbulence levels (FTLs) at 0.4%, 4% and 13% on stall delay are studied using Tomo-PIV system. Static pressure measurements illustrate that FTL has stronger effect on the surface pressures of the static airfoil than those of the rotating blade. Magnitudes of the absolute velocities within the separated flows above the static airfoil's suction surface increase significantly with higher FTL, while, in contrast, the change of these velocities above the rotating blade's surface is less obvious. At the root and middle sections of the rotating blade, the radial flows become wider with higher FTL near the rotating blade's leading edge when the AOAs arc large. At large AOAs, the strength and size of the vortices that shed from the rotating blade's leading and trailing edges decrease significantly with higher FTL. However, at small AOAs, the size and coherence of the vortices near the rotating blade's trailing edge increase significantly with higher FTL. Surface streamlines of the rotating blade illustrate that at the rotating blade's root region and at large AOAs, the streamlines tend to lean toward the rotating blade's trailing edge at higher FTL.Doctor of Philosophy (MAE

Parametric Optimization of Local Resonant Sonic Crystals Window on Noise Attenuation by Using Taguchi Method and ANOVA Analysis

Local resonant sonic crystals (LRSCs) window as a novel design has recently been proposed to achieve a good balance between noise mitigation, natural ventilation and natural lighting. In an effort to explore the feasibilities of such designs in civil residential buildings, an optimization methodology was proposed to develop a more compact LRSCs window with high noise attenuation performance in the present study. Specifically, the Taguchi method was adopted for the design of experiments on the parameters of interest and their corresponding levels, and SN ratio analysis was then applied for the parametric evaluations on the noise attenuation on specified frequencies in traffic noise (concentrated sound energy frequency range: 630–1000 Hz). Three optimal sets of design parameters on the interested frequencies, namely, 630 Hz, 800 Hz and 1000 Hz were obtained. ANOVA analysis was conducted to quantificationally identify the design parameters with statistical significance and remarkable contribution to the desired performance. Results indicate that the slit size has the most significant influence on the overall noise attenuation performance, followed by cavity width. An optimal set of design parameters to achieve the overall best noise reduction performance in the frequency range of 630–1000 Hz was finally determined by combining the SN ratio and ANOVA analysis. A prototype of the final optimized LRSCs window was then fabricated and tested in a semi-anechoic chamber. Good agreement was found between the experiment and numerical simulation. In comparison to the benchmark case, the final optimized design can achieve a further noise reduction by 2.84 dBA, 3.48 dBA and 5.56 dBA for the frequencies of 630 Hz, 800 Hz and 1000 Hz, respectively. The overall noise reduction for the interested frequency range can be promoted by 3.28 dBA. The results indicate that the proposed optimization methodology is practical and efficient in designing a high-performance LRSCs window or improving similar applications

Low-frequency cabin noise of rapid transit trains

Rapid transit or mass rapid transit (MRT) is a high-capacity public transport designed to carry a large number of passengers, especially during the peak hours. They are becoming very popular in major cities and some deem the presence of the rapid transit system in a city as a symbol of modern development and essential feature of urban life. As the rapid transit system expands, the traveling time on a rapid transit train may increase due to longer journey and cabin noise has become an environmental concern for the passengers. In the present study, we would attempt to do a more detailed study of the effect of viaduct height, in particular viaducts of different heights on the cabin noise of various rapid transit systems. The present study examined and benchmarked the cabin noise in terms of both dB(A) and dB(C) for four different rapid transit systems, namely part of the East-West line including the Tuas-West extension on elevated tracks with very high viaduct of the Singapore MRT System; part of Paris Line 2 from Anvers to Belleville station including a stretch of elevated track on viaduct; part of the Piccadilly line of London from Heathrow Airport to Green Park station with a stretch on surface ground; and finally part of Chongqing Line 3 from Gongmao to Lianglukou station across the Yangtze river. It was found that the cabin noise would be dominated by low-frequency content and would be better reflected if the measurements were presented in dB(C), especially for trains running on elevated tracks of greater height

Acoustical Environment Studies in the Modern Urban University Campuses

The quality of the acoustic environments at Xi’an Jiatong-Liverpool University (XJTLU) and Soochow University (Dushuhu Campus, SUDC) in Suzhou City were investigated in the present work through real-time noise level measurements and questionnaire surveys. Before commencing the measurements and surveys, these two campuses’ sound sources were summarized and classified into four categories through on-site observation: human-made, machinery, living creatures, and natural physical sounds. For the zones near the main traffic road, with a high volume of crowds and surrounded by a park, sound from road vehicles, humans talking, and birds/insects were selected by the interviewees as the major sound sources, respectively. Only zone 3 (near to a park) at XJTLU could be classified as A zone (noise level < 55 dBA) with an excellent quality acoustical environment. All other zones had either good or average quality acoustical environments, except zone 1 (near to main traffic road) at XJTLU, with a fair-quality acoustical environment