Whether indoor environmental smoke is harmful for preschool children’s respiratory health in a society where female smoking is rare has not been determined.This study is part of a cross-sectional study(CCHH study-pha...Whether indoor environmental smoke is harmful for preschool children’s respiratory health in a society where female smoking is rare has not been determined.This study is part of a cross-sectional study(CCHH study-phase one in Shanghai)and investigated associations between parental smoking and incense-burning and respiratory symptoms among 4–6 year old children in Shanghai,China.A number of 13335 valid questionnaires(response rate:85.3%)were analyzed.A number of 56.1%(as reported by a parent)of preschool children in Shanghai are exposed to environmental tobacco smoke(ETS).A number of 40.3%of fathers and0.9%of mothers are smokers.A number of 53.7%and 12.6%of Shanghai residents have used mosquito-repellent incense and incensation respectively.Children exposed to any parental smoking have higher prevalence of wheeze and croup than those not exposed.Current maternal smoking has a significant and positive association with wheeze(in the last 12 months,AOR,95%CI:1.83,1.11–2.99).However,paternal smoking either currently or at child’s birth had only weak associations with wheeze and croup.Incense-burning(mosquito-repellent incense and incensation)had significant and negative association with doctor-diagnosed asthma(AOR,95%CI:0.85,0.73–0.99)and hay fever(AOR,95%CI:0.80,0.70–0.93).The results indicate that maternal smoking perhaps is a stronger risk factor for children’s respiratory health than paternal smoking.展开更多
Photothermal catalysis realizes the synergistic effect of solar energy and thermochemistry,which also has the potential to improve the reaction rate and optimize the selectivity.In this review,the research progress of...Photothermal catalysis realizes the synergistic effect of solar energy and thermochemistry,which also has the potential to improve the reaction rate and optimize the selectivity.In this review,the research progress of photothermal catalytic removal of volatile organic compounds(VOCs)by nano-catalysts in recent years is systematically reviewed.First,the fundamentals of photothermal catalysis and the fabrication of catalysts are described,and the design strategy of optimizing photothermal catalysis performance is proposed.Second,the performance for VOC degradation with photothermal catalysis is evaluated and compared for the batch and continuous systems.Particularly,the catalytic mechanism of VOC oxidation is systematically introduced based on experimental and theoretical study.Finally,the future limitations and challenges have been discussed,and potential research directions and priorities are highlighted.A broad view of recent photothermal catalyst fabrication,applications,challenges,and prospects can be systemically provided by this review.展开更多
Aiming at the problem of temperature-mechanics-chemical(T-M-C)action encountered by rocks in underground engineering,sandstone was selected as the sample for acid corrosion treatment at pH 1,3,5 and 7,the acid corrosi...Aiming at the problem of temperature-mechanics-chemical(T-M-C)action encountered by rocks in underground engineering,sandstone was selected as the sample for acid corrosion treatment at pH 1,3,5 and 7,the acid corrosion treated samples were then subjected to high-temperature experiments at 25,300,600,and 900℃,and triaxial compression experiments were conducted in the laboratory.The experimental results show that the superposition of chemical damage and thermal damage has a significant impact on the quality,wave velocity,porosity and compression failure characteristics of the rock.Based on the Lemaitre strain equivalent hypothesis theory,the damage degree of rock material was described by introducing damage variables,and the spatial mobilized plane(SMP)criterion was adopted.The damage constitutive model can well reflect the stress-strain characteristics of the rock triaxial compression process,which verified the rationality and reliability of the model parameters.The experiment and constitutive model analyzed the change law of mechanical properties of rock after chemical corrosion and high temperature thermal damage,which had certain practical significance for rock engineering construction.展开更多
This paper presents fluid mechanics of ventilation system formed by the momentum source and the buoyancy source,which investigates inter-action between the plume and the non-isothermal air jet since buoyancy source is...This paper presents fluid mechanics of ventilation system formed by the momentum source and the buoyancy source,which investigates inter-action between the plume and the non-isothermal air jet since buoyancy source is produced by the plume and momentum source is generated by the air jet,respectively. The interaction is discussed by a mathematical model,an idealized situation of the plume rising from a point heat source of buoyancy alone-in particular the initial momentum flux at the source is zero. Furthermore,the paper discusses the effects of the parameters such as strength of source,air-flow volume and air-flow velocity used in the mathematical-physical model. Considering the effect of the plume generated by the indoor heat source,one expression of trajectory of the non-isothermal air jet produced by jet diffuser is deduced. And field-experiment has also been carried out to illustrate the effect on flowing-action of the air jet and validate the theoretical work. It can be concluded that the heat sources do have effect on the flowing-action of the air jet,and the effect mainly depends on the interaction produced by the plume and the air jet. The results show that the thermal buoyant effect of plumes on the air jet should be taken into account if the indoor heat sources are large enough. Numerical simulation is conducted and coincides with the experimental results as well.展开更多
Formaldehyde is an important carcinogen commonly found indoors.Its indoor sources have been intensively in-vestigated.But study on outdoor formaldehyde concentration,which is potentially an important source to indoors...Formaldehyde is an important carcinogen commonly found indoors.Its indoor sources have been intensively in-vestigated.But study on outdoor formaldehyde concentration,which is potentially an important source to indoors,remains scarce.This study attempts to characterize temporal and spatial distribution of the atmospheric formalde-hyde concentration in Chinese cities.Diurnal variation of ambient formaldehyde was examined in 6 cities and peak hours were identified between 12:00 pm and 3:00 pm.Consequently,outdoor formaldehyde concentrations were measured in the peak hours in 30 cities during the summer months of Jul.-Aug.,2022.The formaldehyde concentrations in the peak hours fell into a range of 0.005-0.087 mg/m^(3)(median value is 0.027 mg/m^(3)),87.7%of which have exceeded the chronic reference exposure criteria of 0.009 mg/m^(3) set by Office of Environmental Health Hazard Assessment.Health risk analysis suggests that exposure to ambient formaldehyde could cause a median carcinogenic risk of 1.9×10^(−5)(3.17×10^(−6)-6.13×10^(−5)),higher than threshold limit of 10−6.Pearson correlation analysis of the 30 cities shows that ambient summertime atmospheric formaldehyde concentrations of the city are positively correlated with its Gross Domestic Product(r=0.48).We also found that the outdoor formaldehyde concentrations in urban areas(median:0.017 mg/m^(3))is slightly higher than those in suburban areas(median:0.013 mg/m^(3)).Results here prove that outdoor formaldehyde is ubiquitous in Chinese cities and reduces effectiveness of ventilation in dilution indoor concentrations.Neglecting it would underestimate air cleaner capacity needed by a factor of about two.It should be accounted for in health analysis and air quality engineering control design of built environment in the future.展开更多
Lithium–sulfur(Li–S)batteries have become one of the most promising candidates for next-generation batteries owing to their high specific capacity,low cost,and environment-friendliness.Many efforts have been made to...Lithium–sulfur(Li–S)batteries have become one of the most promising candidates for next-generation batteries owing to their high specific capacity,low cost,and environment-friendliness.Many efforts have been made to mitigate the"shuttle effect"through physical adsorption and chemical bonding.MoS2 has been proposed as a cathode material to provide effective anchoring sites for lithium polysulfides(Li PSs),but is still limited by its layer structure.Herein,we designed novel MoS2 nanorods with inner caves based on our previous work,and performed synchronous encapsulation of sulfur during the synthesis process.The outer MoS2 tubular shells physically inhibit the outward diffusion of polysulfide species while the inner particles chemically anchor the polysulfides to prevent shuttling.As the cathode matrix in Li–S batteries,the electrochemical results deliver a high initial discharge capacity of 1213 mAhg^-1 for sulfur at 0.1 C.After cycling at 1 C for 300 cycles,the cells exhibit a capacity decay of only 0.076%per cycle and high average coulombic efficiency over 95%.The tubular MoS2 structure is an innovative and appealing design,which could be regarded as a prospective substrate for the improved performance of Li–S batteries.展开更多
The thermal stratification level of low sidewall air supply system in large space was defined. Depending on the experiment of low sidewall air supply in summer 2008,the thermal stratification level was studied by simu...The thermal stratification level of low sidewall air supply system in large space was defined. Depending on the experiment of low sidewall air supply in summer 2008,the thermal stratification level was studied by simulation. Based on the simulation of experiment condition,the air velocity and vertical temperature distribution in a large space were simulated at different air-outlet velocities,and then the thermal stratification level line was obtained. The simulation results well match with the experimental ones and the average relative error is 3.4%. The thermal stratification level is heightened by increasing the air-outlet velocity with low sidewall air supply mode. It is concluded that when air-outlet velocity is 0.29 m/s,which is the experimental case,a uniform thermal environment in the higher occupied zone and a stable stratification level are formed. When the air-outlet velocity is low,such as 0.05 m/s,the thermal stratification level is too low and the air velocity is too small to meet the human thermal comfort in the occupied zone. So,it would be reasonable that the air-outlet velocity may be designed as 0.31 m/s if the height of the occupied zone is 2 m.展开更多
Hydration heat behavior and kinetics of blended cement containing up to 20% MSWI fly ash were investigated based on its hydration heat evolution rate measured by isothermal calorimeter. Kinetics parameters, N and K, a...Hydration heat behavior and kinetics of blended cement containing up to 20% MSWI fly ash were investigated based on its hydration heat evolution rate measured by isothermal calorimeter. Kinetics parameters, N and K, and hydration degree, Ca(OH)2 content, were also calculated and analyzed. According to the experimental results, the induction period was elongated, the second heat evolution peak was in advance, and the third hydration heat peak could be detected due to MSWI fly ash pozzolanic reaction. The hydration reaction rate was controlled by nucleation kinetics in the acceleration period and then by diffusion in the decay period, but in the deceleration period, the hydration experienced a dual controlling reaction of autocatalytic chemical reaction and diffusion. The hydration rate of blended cement was faster. Ca(OH)2 content increased before 14 days.展开更多
Based on the thermal and velocity layer's theory,the experimental setup was established on large space atrium under nozzle outlet. A series of winter experiments were accomplished and the following conclusions cou...Based on the thermal and velocity layer's theory,the experimental setup was established on large space atrium under nozzle outlet. A series of winter experiments were accomplished and the following conclusions could be drawn. At the sunny day of winter in Shanghai,the thermal and velocity layer are similar. The height of the both layer is 10-30 mm,and the temperature gratitude is 5-10 ℃ /m. Decreasing the angle of the nozzle outlet can increase the layer height dramatically. The maximum temperature difference of the occupant zone has relation with the angle of the nozzle outlet. The less the angle of the nozzle outlet is set,the greater the temperature difference is. The occupant temperature differences at these angles of the nozzle outlet are 5.1-4.4 ℃. The velocity of the wind is 0.02 and 0.17 m/s and they can accord with design demand. So,it can decrease the temperature gratitude by about 30% and it can save 10%-15% energy consumption.展开更多
This paper focuses on the analytical derivation and the numerical simulation analyses to predict the interaction influences between a landslide and a new tunnel in mountain areas. Based on the slip-line theory, the di...This paper focuses on the analytical derivation and the numerical simulation analyses to predict the interaction influences between a landslide and a new tunnel in mountain areas. Based on the slip-line theory, the disturbance range induced by tunneling and the minimum safe distance between the tunnel vault and the sliding belt are obtained in consideration of the mechanical analyses of relaxed rocks over the tunnel opening. The influence factors for the minimum safe crossing distance are conducted,including the tunnel radius, the friction angle of surrounding rocks, the inclination angle of sliding belt,and the friction coefficient of surrounding rocks. Secondly, taking account of the compressive zone and relaxed rocks caused by tunneling, the Sarma method is employed to calculate the safety factor of landslide. Finally, the analytical solutions for interaction between the tunnel and the landslide are compared with a series of numerical simulations, considering the cases for different perpendicular distances between the tunnel vault and the sliding belt. Resultsshow that the distance between the tunnel vault and the slip zone has significant influence on the rock stress and strain. For the case of the minimum crossing distance, a plastic zone in the landslide traversed by tunneling would be formed with rather large range, which seriously threatens the stability of landslide. This work demonstrates that the minimum safe crossing distance obtained from numerical simulation is in a good agreement with that calculated by the proposed analytical solutions.展开更多
Long-term settlements for underground structures, such as tunnels and pipelines, are generally observed after the completion of construction in soft clay. The soil consolidation characteristic has great influences on ...Long-term settlements for underground structures, such as tunnels and pipelines, are generally observed after the completion of construction in soft clay. The soil consolidation characteristic has great influences on the long-term deformation for underground structures. A three-dimensional consolidation analysis method under the asymmetric loads is developed for porous layered soil based on Biot's classical theory. Time-displacement effects can be fully considered in this work and the analytical solutions are obtained by the state space approach in the Cartesian coordinate. The Laplace and double Fourier integral transform are applied to the state variables in order to reduce the partial differential equations into algebraic differential equations and easily obtain the state space solution. Starting from the governing equations of saturated porous soil, the basic relationship of state space variables is established between the ground surface and the arbitrary depth in the integral transform domain. Based on the continuity conditions and boundary conditions of the multi-layered pore soil model, the multi-layered pore half-space solutions are obtained by means of the transfer matrix method and the inverse integral transforms. The accuracy of proposed method is demonstrated with existing classical solutions. The results indicate that the porous homogenous soils as well as the porous non-homogenous layered soils can be considered in this proposed method. When the consolidation time factor is 0.01, the value of immediate consolidation settlement coefficient calculated by the weighted homogenous solution is 27.4% bigger than the one calculated by the non-homogeneity solution. When the consolidation time factor is 0.05, the value of excess pore water pressure for the weighted homogenous solution is 27.2% bigger than the one for the non-homogeneity solution. It is shown that the material non-homogeneity has a great influence on the long-term settlements and the dissipation process of excess pore water pressure.展开更多
Palm fiber is one of the favorable materials used in stabilization of soft soil in geotechnical engineering projects in recent years due to its nature of sustainability,no harm to the environment,biodegradability,avai...Palm fiber is one of the favorable materials used in stabilization of soft soil in geotechnical engineering projects in recent years due to its nature of sustainability,no harm to the environment,biodegradability,availability and costeffectiveness in the context of widespread appeal from the world for returning to nature and protecting the earth our homestead.This paper is aimed at exploring the mechanical performance of Shanghai clayey soil reinforced with palm fiber.The unconfined compressive tests are carried out on samples treated with palm fibers of different lengths and contents,and the unconfined compressive strength(UCS),ductility rate(DR),secant modulus(SM),energy absorption capacity(EAC)and failure pattern(FP)of the reinforced and unreinforced samples have been analyzed with regard to their relationship with palm fiber contents and lengths.Then multiple regression,grey correlation and general correlation relationship analysis are applied to the resultant test data so as to obtain the mathematical and statistical equation of related soil indexes.It has been concluded from the analysis that the unconfined compressive strength,ductility and energy absorption capacity of reinforced soil will increase with the increase in content and length of palm fiber,which are maximized when palm fiber content and length are 0.4%and 15 mm,respectively.On the contrary,the secant modulus of reinforced soil decreases considerably with content and length of palm fiber as a whole.Additionally,the failure pattern also changes from brittle to ductile gradually with the content and length of palm fiber.The data provided by the analysis of reinforced soil can be referred to and used for the related geotechnical engineering in the future.And the mathematical model obtained from the statistical regression is significantly meaningful because it can be used to predict the soil performance without the need for doing the additional tests,with saving in cost and time.What’s more,the application of palm fiber to soft soil is completely in accordance to the concept of sustainable development and environment protection.展开更多
The experiment was conducted to investigate the heat transfer performance of supercritical CO_2 in a casing heat exchanger by comparing their heat transfer,entropy production unit number,non-dimensional entropy produc...The experiment was conducted to investigate the heat transfer performance of supercritical CO_2 in a casing heat exchanger by comparing their heat transfer,entropy production unit number,non-dimensional entropy production rate and field synergy factor.The results show that both heat transfer and entropy production unit number in four tubes decrease with water temperature increasing.Heat transfer and entropy production unit number in multiple tubes( i. e.,triple straight tube and double helix tube) is higher than their single counterparts; the non-dimensional entropy production rate increases with water temperature. Non-dimensional entropy production rate of triple straight tube and double helix tube is far below the single tube. Field synergy factor of double helix tube is much higher than that of the triple straight tube under the same condition. Further experiment was carried out in double helix tube,under various CO_2 pressure and inlet water temperature,the results are analyzed and reported in this paper.展开更多
Indoor air environment includes indoor thermal environment and air quality, and a reasonable ventilation provides guarantee for a good indoor environment. A numerical study of the indoor environment in different venti...Indoor air environment includes indoor thermal environment and air quality, and a reasonable ventilation provides guarantee for a good indoor environment. A numerical study of the indoor environment in different ventilation is presented in this paper. The External Energy Saving Lab of the WenYuan Building was selected for this purpose, and its indoor air quality and thermal performance in the typical summer climate were simulated. For the numerical simulation, the techniques of Fluent Air-pak was adopted to establish the physical and numerical model of lab. A attention is given to the velocity field and the distribution of pollutant concentration, followed by a discussion of two ventilation modes (displacement ventilation and up-in and up-out ventilation). By comparison, it is found that the Displacement ventilation in improving indoor air quality is obviously superior to the traditional up-in and up-out ventilation.展开更多
In the hot summer&cold winter zone in China,intermittent heating space for rooms is widely used.However,in comparison with continuous space heating,the energy-saving performance of intermittent space heating has n...In the hot summer&cold winter zone in China,intermittent heating space for rooms is widely used.However,in comparison with continuous space heating,the energy-saving performance of intermittent space heating has not been sufficiently investigated.This paper studied the factors influencing the energy performance of intermittent heating for the representativeoffice inhot summer&coldwinter zone.Basedon theheatbalancemethod,adynamic thermalmodel of the intermittent heating roomwas built and tested by experiments.And then,it analyzed the total space heating load,the amount of energy saving and energy saving ratio of the intermittent heating under different preheating hours,occupation hours,required roomtemperatures,air change rates,overall heat transfer coefficients(U-value)of windows and wall materials.If the adjacent rooms were not heated,for a typical room occupied about 10 h a day,the energy-saving ratio of intermittent heating was about 30%compared with continuous heating.But the preheating power was higher than two times of continuous heating.The results also indicated that the occupation hours had a significant effect on energy saving amount and ratio,it should be noted that the energy saving ratio by intermittent heating was much lower than the unoccupied period ratio.Relative to other factors,the heating temperatures,room air change rates and U-value of windows,and room envelope materials had little effect on energy efficiency.If the adjacent rooms were heated in the same manner as the roomin question,the energy-saving ratio of the total load of intermittent heating was heavily reduced to 8.46%.展开更多
Rechargeable magnesium ion batteries(RMBs)are investigated as lithium-ion batteries(LIBs)alternative owing to their favorable merits of high energy density,abundance and low expenditure of Mg,as well a especially non-...Rechargeable magnesium ion batteries(RMBs)are investigated as lithium-ion batteries(LIBs)alternative owing to their favorable merits of high energy density,abundance and low expenditure of Mg,as well a especially non-toxic safety and low risk of dendrite formation in anodes,which endows them to be more easily assembled in electric-power vehicles for the extended application of civilian-military fields.Never theless,the high charge density,strong polarization effect,and slow diffusion kinetics of Mg^(2+)remain a large obstacle and thus enormous efforts have to be paid to mend the gap with commercial demand fo cathode materials.At present,RMBs cathode materials mainly contain transition metal sulfides/oxides polyanionic compounds and Prussian blue analogs,and several methods such as nano structuring,dop ing regulation and coating modification have been applied to materials design for better performance In this paper,the current research status of RMBs cathode materials at home&abroad is arranged and summarized along with challenges of development in the future focusing on synthesis of RMBs cathode materials with high energy density as well as satisfactory cycling performance.And this analysis aims to provide reference and basis for researchers working on RMBs technology advancement.展开更多
Heterogeneous reaction of mineral aerosols and atmospheric polluting gases play an important role in atmospheric chemistry.In this study,the reactions of NO_(2) with or without SO_(2) mixture gas on the surface of α-...Heterogeneous reaction of mineral aerosols and atmospheric polluting gases play an important role in atmospheric chemistry.In this study,the reactions of NO_(2) with or without SO_(2) mixture gas on the surface of α-Fe_(2)O_(3) particles under dry conditions were studied.The effects of sodium dodecyl sulfate(SDS)and the heterogeneous reaction under both dark and UV irradiation conditions were investigated.The infrared spectrum analyzed by the two-dimensional correlation spectroscopy(2D-COS)was used to obtain the products formation sequences.The results showed that UV irradiation can promote the production of nitrate.The 2D-COS analysis indicated SDS changed the sequence order of nitrate and nitrite species during reactions.In oxidation conditions,the final product of heterogeneous reaction of NO_(2) and α-Fe_(2)O_(3) was monodentate nitrate.Only the heterogenous reaction of NO_(2) and α-Fe_(2)O_(3) containing SDS(FOS)without UV light,the final product was bidentate nitrate.SDS was the catalysis agent supply and photoresist to the system.With surface active compounds,the environmental lifetime of heterogeneous reactions between trace gases and aerosols extends.Surfactants,ultraviolet light,and the types of gases involved in the reaction all have complex effects on the aerosol aging process.This study provided a reference for subsequent heterogeneous reaction studies and the formation of aerosols.展开更多
Buildings with large open spaces in which chemicals are handled are often exposed to the risk of explosions.Computational fluid dynamics is a useful and convenient way to investigate contaminant dispersion in such lar...Buildings with large open spaces in which chemicals are handled are often exposed to the risk of explosions.Computational fluid dynamics is a useful and convenient way to investigate contaminant dispersion in such large spaces.The turbulent Schmidt number(Sc_(t))concept has typically been used in this regard,and most studies have adopted a default value.We studied the concentration distribution for sulfur hexafluoride(SF_(6))assuming different emission rates and considering the effect of Sc_(t).Then we examined the same problem for a light gas by assuming hydrogen gas(H_(2))as the contaminant.When SF_(6) was considered as the contaminant gas,a variation in the emission rate completely changed the concentration distribution.When the emission rate was low,the gravitational effect did not take place.For both low and high emission rates,an increase in S_(ct) accelerated the transport rate of SF_(6).In contrast,for H_(2) as the contaminant gas,a larger S_(ct) could induce a decrease in the H_(2) transport rate.展开更多
The on-going COVID-19 pandemic has wrecked havoc in our society,with short and long-term consequences to people’s lives and livelihoods-over 651 million COVID-19 cases have been confirmed with the number of deaths ex...The on-going COVID-19 pandemic has wrecked havoc in our society,with short and long-term consequences to people’s lives and livelihoods-over 651 million COVID-19 cases have been confirmed with the number of deaths exceeding 6.66 million.As people stay indoors most of the time,how to operate the Heating,Ventilation and Air-Conditioning(HVAC)systems as well as building facilities to reduce airborne infections have become hot research topics.This paper presents a systematic review on COVID-19 related research in HVAC systems and the indoor environment.Firstly,it reviews the research on the improvement of ventilation,filtration,heating and air-conditioning systems since the onset of COVID-19.Secondly,various indoor environment improvement measures to minimize airborne spread,such as building envelope design,physical barriers and vent position arrangement,and the possible impact of COVID-19 on building energy consumption are examined.Thirdly,it provides comparisons on the building operation guidelines for preventing the spread of COVID-19 virus from different countries.Finally,recommendations for future studies are provided.展开更多
Outbreaks of airborne infections during meal consumption in diverse restaurant settings have been extensively reported.It is widely recognized that effective ventilation strategies are essential to minimize the infect...Outbreaks of airborne infections during meal consumption in diverse restaurant settings have been extensively reported.It is widely recognized that effective ventilation strategies are essential to minimize the infection risk in indoor environments,and these strategies should be tailored to the heat sources.The purpose of this study is to compare the spatial distribution of risk in restaurant rooms that use mixing or displacement ventilation,specif-ically focusing on the heat sources used for different food types,namely hotpot,normal Chinese food,and iced food.Computational Fluid Dynamics(CFD)was employed to assess exposure risk.Our results indicate that the use of low-temperature heat sources can elevate the risk of infection by increasing the local vertical temperature gradient.In comparison to no heat source,the risk increased by 190.9%and 99.6%for displacement and mixing ventilation strategies,respectively.Under mixing ventilation,both low-temperature and no heat sources showed lower infection risks when compared to displacement ventilation.However,displacement ventilation is found to be highly effective in reducing the risk of infection when using a high-temperature heat source,with only 12.3%of the infection risk observed in mixing ventilation.Furthermore,the use of displacement ventilation resulted in a significant reduction in the odors emitted by hotpot,which were instead absorbed by clothes in the mixing ven-tilation scenario.Our findings provide crucial insights into the development of appropriate ventilation strategies for reducing personal exposure to airborne infections in diverse restaurant settings.Specifically,we recommend using displacement ventilation in restaurants that utilize high-temperature heat sources,as it can substantially reduce the risk of infection.展开更多
基金supported by the Leading Academic Discipline Project of Shanghai Municipal Education Commission(J50502)the NationalNatural Science Foundation of China(51108263 and 51278302)the Shanghai Municipal and District Bureau of Education for their supports
文摘Whether indoor environmental smoke is harmful for preschool children’s respiratory health in a society where female smoking is rare has not been determined.This study is part of a cross-sectional study(CCHH study-phase one in Shanghai)and investigated associations between parental smoking and incense-burning and respiratory symptoms among 4–6 year old children in Shanghai,China.A number of 13335 valid questionnaires(response rate:85.3%)were analyzed.A number of 56.1%(as reported by a parent)of preschool children in Shanghai are exposed to environmental tobacco smoke(ETS).A number of 40.3%of fathers and0.9%of mothers are smokers.A number of 53.7%and 12.6%of Shanghai residents have used mosquito-repellent incense and incensation respectively.Children exposed to any parental smoking have higher prevalence of wheeze and croup than those not exposed.Current maternal smoking has a significant and positive association with wheeze(in the last 12 months,AOR,95%CI:1.83,1.11–2.99).However,paternal smoking either currently or at child’s birth had only weak associations with wheeze and croup.Incense-burning(mosquito-repellent incense and incensation)had significant and negative association with doctor-diagnosed asthma(AOR,95%CI:0.85,0.73–0.99)and hay fever(AOR,95%CI:0.80,0.70–0.93).The results indicate that maternal smoking perhaps is a stronger risk factor for children’s respiratory health than paternal smoking.
基金sponsored financially by the National Natural Science Foundation of China (No.21906104 and No.12175145)the Shanghai Rising-Star Program (21QA1406600).
文摘Photothermal catalysis realizes the synergistic effect of solar energy and thermochemistry,which also has the potential to improve the reaction rate and optimize the selectivity.In this review,the research progress of photothermal catalytic removal of volatile organic compounds(VOCs)by nano-catalysts in recent years is systematically reviewed.First,the fundamentals of photothermal catalysis and the fabrication of catalysts are described,and the design strategy of optimizing photothermal catalysis performance is proposed.Second,the performance for VOC degradation with photothermal catalysis is evaluated and compared for the batch and continuous systems.Particularly,the catalytic mechanism of VOC oxidation is systematically introduced based on experimental and theoretical study.Finally,the future limitations and challenges have been discussed,and potential research directions and priorities are highlighted.A broad view of recent photothermal catalyst fabrication,applications,challenges,and prospects can be systemically provided by this review.
文摘Aiming at the problem of temperature-mechanics-chemical(T-M-C)action encountered by rocks in underground engineering,sandstone was selected as the sample for acid corrosion treatment at pH 1,3,5 and 7,the acid corrosion treated samples were then subjected to high-temperature experiments at 25,300,600,and 900℃,and triaxial compression experiments were conducted in the laboratory.The experimental results show that the superposition of chemical damage and thermal damage has a significant impact on the quality,wave velocity,porosity and compression failure characteristics of the rock.Based on the Lemaitre strain equivalent hypothesis theory,the damage degree of rock material was described by introducing damage variables,and the spatial mobilized plane(SMP)criterion was adopted.The damage constitutive model can well reflect the stress-strain characteristics of the rock triaxial compression process,which verified the rationality and reliability of the model parameters.The experiment and constitutive model analyzed the change law of mechanical properties of rock after chemical corrosion and high temperature thermal damage,which had certain practical significance for rock engineering construction.
基金Sponsored by the National Natural Science Foundation of China (Grant No 50478113)the Key Project of Shanghai Education Committee (Grant NoJ50502)Special Research Fund in Shanghai Colleges and Universities to Select and Train Outstanding Young Teachers (Grant No slg09011)
文摘This paper presents fluid mechanics of ventilation system formed by the momentum source and the buoyancy source,which investigates inter-action between the plume and the non-isothermal air jet since buoyancy source is produced by the plume and momentum source is generated by the air jet,respectively. The interaction is discussed by a mathematical model,an idealized situation of the plume rising from a point heat source of buoyancy alone-in particular the initial momentum flux at the source is zero. Furthermore,the paper discusses the effects of the parameters such as strength of source,air-flow volume and air-flow velocity used in the mathematical-physical model. Considering the effect of the plume generated by the indoor heat source,one expression of trajectory of the non-isothermal air jet produced by jet diffuser is deduced. And field-experiment has also been carried out to illustrate the effect on flowing-action of the air jet and validate the theoretical work. It can be concluded that the heat sources do have effect on the flowing-action of the air jet,and the effect mainly depends on the interaction produced by the plume and the air jet. The results show that the thermal buoyant effect of plumes on the air jet should be taken into account if the indoor heat sources are large enough. Numerical simulation is conducted and coincides with the experimental results as well.
基金financially supported by the National Natural Science Foundation of China (no.52178068)the Fundamental Research Funds for the Central Universities-Zhishan Young Scholars Project (no.2242022R40005).
文摘Formaldehyde is an important carcinogen commonly found indoors.Its indoor sources have been intensively in-vestigated.But study on outdoor formaldehyde concentration,which is potentially an important source to indoors,remains scarce.This study attempts to characterize temporal and spatial distribution of the atmospheric formalde-hyde concentration in Chinese cities.Diurnal variation of ambient formaldehyde was examined in 6 cities and peak hours were identified between 12:00 pm and 3:00 pm.Consequently,outdoor formaldehyde concentrations were measured in the peak hours in 30 cities during the summer months of Jul.-Aug.,2022.The formaldehyde concentrations in the peak hours fell into a range of 0.005-0.087 mg/m^(3)(median value is 0.027 mg/m^(3)),87.7%of which have exceeded the chronic reference exposure criteria of 0.009 mg/m^(3) set by Office of Environmental Health Hazard Assessment.Health risk analysis suggests that exposure to ambient formaldehyde could cause a median carcinogenic risk of 1.9×10^(−5)(3.17×10^(−6)-6.13×10^(−5)),higher than threshold limit of 10−6.Pearson correlation analysis of the 30 cities shows that ambient summertime atmospheric formaldehyde concentrations of the city are positively correlated with its Gross Domestic Product(r=0.48).We also found that the outdoor formaldehyde concentrations in urban areas(median:0.017 mg/m^(3))is slightly higher than those in suburban areas(median:0.013 mg/m^(3)).Results here prove that outdoor formaldehyde is ubiquitous in Chinese cities and reduces effectiveness of ventilation in dilution indoor concentrations.Neglecting it would underestimate air cleaner capacity needed by a factor of about two.It should be accounted for in health analysis and air quality engineering control design of built environment in the future.
基金supported by the National Natural Science Foundation of China(No.21771143)Natural Science Foundation of Shaanxi Province(grant no.2017ZDJC-30,2018JQ2027)+4 种基金Key Research Project of Shaanxi Province(2018ZDCXLGY-08-06)Natural Science Foundation of Jiangsu Province(grant no.BK20170413)Fundamental Research Funds for the Central Universities(grant no.xjj2017084)Foshan Science and Technology Bureau Project(No.2017AG100443)supported by the Cyrus Tang Foundation through the Tang Scholar Program。
文摘Lithium–sulfur(Li–S)batteries have become one of the most promising candidates for next-generation batteries owing to their high specific capacity,low cost,and environment-friendliness.Many efforts have been made to mitigate the"shuttle effect"through physical adsorption and chemical bonding.MoS2 has been proposed as a cathode material to provide effective anchoring sites for lithium polysulfides(Li PSs),but is still limited by its layer structure.Herein,we designed novel MoS2 nanorods with inner caves based on our previous work,and performed synchronous encapsulation of sulfur during the synthesis process.The outer MoS2 tubular shells physically inhibit the outward diffusion of polysulfide species while the inner particles chemically anchor the polysulfides to prevent shuttling.As the cathode matrix in Li–S batteries,the electrochemical results deliver a high initial discharge capacity of 1213 mAhg^-1 for sulfur at 0.1 C.After cycling at 1 C for 300 cycles,the cells exhibit a capacity decay of only 0.076%per cycle and high average coulombic efficiency over 95%.The tubular MoS2 structure is an innovative and appealing design,which could be regarded as a prospective substrate for the improved performance of Li–S batteries.
基金Project(50478113) supported by the National Natural Science Foundation of ChinaProject(J50502) supported by the Leading Academic Discipline Project of Shanghai Municipal Education Commission,China
文摘The thermal stratification level of low sidewall air supply system in large space was defined. Depending on the experiment of low sidewall air supply in summer 2008,the thermal stratification level was studied by simulation. Based on the simulation of experiment condition,the air velocity and vertical temperature distribution in a large space were simulated at different air-outlet velocities,and then the thermal stratification level line was obtained. The simulation results well match with the experimental ones and the average relative error is 3.4%. The thermal stratification level is heightened by increasing the air-outlet velocity with low sidewall air supply mode. It is concluded that when air-outlet velocity is 0.29 m/s,which is the experimental case,a uniform thermal environment in the higher occupied zone and a stable stratification level are formed. When the air-outlet velocity is low,such as 0.05 m/s,the thermal stratification level is too low and the air velocity is too small to meet the human thermal comfort in the occupied zone. So,it would be reasonable that the air-outlet velocity may be designed as 0.31 m/s if the height of the occupied zone is 2 m.
基金Funded by the National Natural Science Foundation of China(No.51172164)
文摘Hydration heat behavior and kinetics of blended cement containing up to 20% MSWI fly ash were investigated based on its hydration heat evolution rate measured by isothermal calorimeter. Kinetics parameters, N and K, and hydration degree, Ca(OH)2 content, were also calculated and analyzed. According to the experimental results, the induction period was elongated, the second heat evolution peak was in advance, and the third hydration heat peak could be detected due to MSWI fly ash pozzolanic reaction. The hydration reaction rate was controlled by nucleation kinetics in the acceleration period and then by diffusion in the decay period, but in the deceleration period, the hydration experienced a dual controlling reaction of autocatalytic chemical reaction and diffusion. The hydration rate of blended cement was faster. Ca(OH)2 content increased before 14 days.
基金Project(09YZ229) supported by Innovation Program of Shanghai Municipal Education Commission, ChinaProject(J50502) supported by Leading Academic Discipline of Shanghai Municipal Education Commission,China+2 种基金Project(50478113) supported by the National Natural Science Foundation of ChinaProject(2006BAJ02A05) supported by the National Key Technology R&D Program,ChinaProject(08DZ1203600) supported by the Shanghai Municipal Sciences and Technology Committee,China
文摘Based on the thermal and velocity layer's theory,the experimental setup was established on large space atrium under nozzle outlet. A series of winter experiments were accomplished and the following conclusions could be drawn. At the sunny day of winter in Shanghai,the thermal and velocity layer are similar. The height of the both layer is 10-30 mm,and the temperature gratitude is 5-10 ℃ /m. Decreasing the angle of the nozzle outlet can increase the layer height dramatically. The maximum temperature difference of the occupant zone has relation with the angle of the nozzle outlet. The less the angle of the nozzle outlet is set,the greater the temperature difference is. The occupant temperature differences at these angles of the nozzle outlet are 5.1-4.4 ℃. The velocity of the wind is 0.02 and 0.17 m/s and they can accord with design demand. So,it can decrease the temperature gratitude by about 30% and it can save 10%-15% energy consumption.
基金financial support provided by Natural Science Foundation of China (Grant No. 51008188)by Shanghai Natural Science Foundation (Grant No. 15ZR1429400)+2 种基金by Open Project Program of State Key Laboratory Breeding Base of Mountain Bridge and Tunnel Engineering (Grant No. CQSLBF-Y15-1)by Open Project Program of State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (Grant No. SKLGP2015K015)by the Open Project Program of Key Laboratory of Geohazard Prevention of Hilly Mountains, Ministry of Land and Resources (Grant No. 2015k005)
文摘This paper focuses on the analytical derivation and the numerical simulation analyses to predict the interaction influences between a landslide and a new tunnel in mountain areas. Based on the slip-line theory, the disturbance range induced by tunneling and the minimum safe distance between the tunnel vault and the sliding belt are obtained in consideration of the mechanical analyses of relaxed rocks over the tunnel opening. The influence factors for the minimum safe crossing distance are conducted,including the tunnel radius, the friction angle of surrounding rocks, the inclination angle of sliding belt,and the friction coefficient of surrounding rocks. Secondly, taking account of the compressive zone and relaxed rocks caused by tunneling, the Sarma method is employed to calculate the safety factor of landslide. Finally, the analytical solutions for interaction between the tunnel and the landslide are compared with a series of numerical simulations, considering the cases for different perpendicular distances between the tunnel vault and the sliding belt. Resultsshow that the distance between the tunnel vault and the slip zone has significant influence on the rock stress and strain. For the case of the minimum crossing distance, a plastic zone in the landslide traversed by tunneling would be formed with rather large range, which seriously threatens the stability of landslide. This work demonstrates that the minimum safe crossing distance obtained from numerical simulation is in a good agreement with that calculated by the proposed analytical solutions.
基金Project(51008188)supported by National Natural Science Foundation of ChinaProject(KLE-TJGE-B1302)supported by Key Laboratory Fund of Geotechnical and Underground Engineering of Ministry of Education,ChinaProject(SKLGDUEK1205)supported by Open Program of State Key Laboratory for Geomechanics and Deep Underground Engineering,China
文摘Long-term settlements for underground structures, such as tunnels and pipelines, are generally observed after the completion of construction in soft clay. The soil consolidation characteristic has great influences on the long-term deformation for underground structures. A three-dimensional consolidation analysis method under the asymmetric loads is developed for porous layered soil based on Biot's classical theory. Time-displacement effects can be fully considered in this work and the analytical solutions are obtained by the state space approach in the Cartesian coordinate. The Laplace and double Fourier integral transform are applied to the state variables in order to reduce the partial differential equations into algebraic differential equations and easily obtain the state space solution. Starting from the governing equations of saturated porous soil, the basic relationship of state space variables is established between the ground surface and the arbitrary depth in the integral transform domain. Based on the continuity conditions and boundary conditions of the multi-layered pore soil model, the multi-layered pore half-space solutions are obtained by means of the transfer matrix method and the inverse integral transforms. The accuracy of proposed method is demonstrated with existing classical solutions. The results indicate that the porous homogenous soils as well as the porous non-homogenous layered soils can be considered in this proposed method. When the consolidation time factor is 0.01, the value of immediate consolidation settlement coefficient calculated by the weighted homogenous solution is 27.4% bigger than the one calculated by the non-homogeneity solution. When the consolidation time factor is 0.05, the value of excess pore water pressure for the weighted homogenous solution is 27.2% bigger than the one for the non-homogeneity solution. It is shown that the material non-homogeneity has a great influence on the long-term settlements and the dissipation process of excess pore water pressure.
基金The authors will also thank Shanghai municipal government for financial support(No.57-19-119-002).
文摘Palm fiber is one of the favorable materials used in stabilization of soft soil in geotechnical engineering projects in recent years due to its nature of sustainability,no harm to the environment,biodegradability,availability and costeffectiveness in the context of widespread appeal from the world for returning to nature and protecting the earth our homestead.This paper is aimed at exploring the mechanical performance of Shanghai clayey soil reinforced with palm fiber.The unconfined compressive tests are carried out on samples treated with palm fibers of different lengths and contents,and the unconfined compressive strength(UCS),ductility rate(DR),secant modulus(SM),energy absorption capacity(EAC)and failure pattern(FP)of the reinforced and unreinforced samples have been analyzed with regard to their relationship with palm fiber contents and lengths.Then multiple regression,grey correlation and general correlation relationship analysis are applied to the resultant test data so as to obtain the mathematical and statistical equation of related soil indexes.It has been concluded from the analysis that the unconfined compressive strength,ductility and energy absorption capacity of reinforced soil will increase with the increase in content and length of palm fiber,which are maximized when palm fiber content and length are 0.4%and 15 mm,respectively.On the contrary,the secant modulus of reinforced soil decreases considerably with content and length of palm fiber as a whole.Additionally,the failure pattern also changes from brittle to ductile gradually with the content and length of palm fiber.The data provided by the analysis of reinforced soil can be referred to and used for the related geotechnical engineering in the future.And the mathematical model obtained from the statistical regression is significantly meaningful because it can be used to predict the soil performance without the need for doing the additional tests,with saving in cost and time.What’s more,the application of palm fiber to soft soil is completely in accordance to the concept of sustainable development and environment protection.
基金Hujiang Foundation of China(No.D14003)Yangtze River Delta Technology Joint Research,China(No.10195811000)
文摘The experiment was conducted to investigate the heat transfer performance of supercritical CO_2 in a casing heat exchanger by comparing their heat transfer,entropy production unit number,non-dimensional entropy production rate and field synergy factor.The results show that both heat transfer and entropy production unit number in four tubes decrease with water temperature increasing.Heat transfer and entropy production unit number in multiple tubes( i. e.,triple straight tube and double helix tube) is higher than their single counterparts; the non-dimensional entropy production rate increases with water temperature. Non-dimensional entropy production rate of triple straight tube and double helix tube is far below the single tube. Field synergy factor of double helix tube is much higher than that of the triple straight tube under the same condition. Further experiment was carried out in double helix tube,under various CO_2 pressure and inlet water temperature,the results are analyzed and reported in this paper.
文摘Indoor air environment includes indoor thermal environment and air quality, and a reasonable ventilation provides guarantee for a good indoor environment. A numerical study of the indoor environment in different ventilation is presented in this paper. The External Energy Saving Lab of the WenYuan Building was selected for this purpose, and its indoor air quality and thermal performance in the typical summer climate were simulated. For the numerical simulation, the techniques of Fluent Air-pak was adopted to establish the physical and numerical model of lab. A attention is given to the velocity field and the distribution of pollutant concentration, followed by a discussion of two ventilation modes (displacement ventilation and up-in and up-out ventilation). By comparison, it is found that the Displacement ventilation in improving indoor air quality is obviously superior to the traditional up-in and up-out ventilation.
基金supported by the National Natural Science Foundation of China(No.71974129).
文摘In the hot summer&cold winter zone in China,intermittent heating space for rooms is widely used.However,in comparison with continuous space heating,the energy-saving performance of intermittent space heating has not been sufficiently investigated.This paper studied the factors influencing the energy performance of intermittent heating for the representativeoffice inhot summer&coldwinter zone.Basedon theheatbalancemethod,adynamic thermalmodel of the intermittent heating roomwas built and tested by experiments.And then,it analyzed the total space heating load,the amount of energy saving and energy saving ratio of the intermittent heating under different preheating hours,occupation hours,required roomtemperatures,air change rates,overall heat transfer coefficients(U-value)of windows and wall materials.If the adjacent rooms were not heated,for a typical room occupied about 10 h a day,the energy-saving ratio of intermittent heating was about 30%compared with continuous heating.But the preheating power was higher than two times of continuous heating.The results also indicated that the occupation hours had a significant effect on energy saving amount and ratio,it should be noted that the energy saving ratio by intermittent heating was much lower than the unoccupied period ratio.Relative to other factors,the heating temperatures,room air change rates and U-value of windows,and room envelope materials had little effect on energy efficiency.If the adjacent rooms were heated in the same manner as the roomin question,the energy-saving ratio of the total load of intermittent heating was heavily reduced to 8.46%.
基金financially supported by the National Natural Science Foundation of China(Nos.21804008,52102209)the International Technological Collaboration Project of Shanghai(No.17520710300)+1 种基金Anhui Provincial Natural Science Foundation(No.2108085QE197)Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515010834,2020A1515110221)。
文摘Rechargeable magnesium ion batteries(RMBs)are investigated as lithium-ion batteries(LIBs)alternative owing to their favorable merits of high energy density,abundance and low expenditure of Mg,as well a especially non-toxic safety and low risk of dendrite formation in anodes,which endows them to be more easily assembled in electric-power vehicles for the extended application of civilian-military fields.Never theless,the high charge density,strong polarization effect,and slow diffusion kinetics of Mg^(2+)remain a large obstacle and thus enormous efforts have to be paid to mend the gap with commercial demand fo cathode materials.At present,RMBs cathode materials mainly contain transition metal sulfides/oxides polyanionic compounds and Prussian blue analogs,and several methods such as nano structuring,dop ing regulation and coating modification have been applied to materials design for better performance In this paper,the current research status of RMBs cathode materials at home&abroad is arranged and summarized along with challenges of development in the future focusing on synthesis of RMBs cathode materials with high energy density as well as satisfactory cycling performance.And this analysis aims to provide reference and basis for researchers working on RMBs technology advancement.
基金supported by the National Natural Science Foundation of China(Nos.41807304 and 22206130)。
文摘Heterogeneous reaction of mineral aerosols and atmospheric polluting gases play an important role in atmospheric chemistry.In this study,the reactions of NO_(2) with or without SO_(2) mixture gas on the surface of α-Fe_(2)O_(3) particles under dry conditions were studied.The effects of sodium dodecyl sulfate(SDS)and the heterogeneous reaction under both dark and UV irradiation conditions were investigated.The infrared spectrum analyzed by the two-dimensional correlation spectroscopy(2D-COS)was used to obtain the products formation sequences.The results showed that UV irradiation can promote the production of nitrate.The 2D-COS analysis indicated SDS changed the sequence order of nitrate and nitrite species during reactions.In oxidation conditions,the final product of heterogeneous reaction of NO_(2) and α-Fe_(2)O_(3) was monodentate nitrate.Only the heterogenous reaction of NO_(2) and α-Fe_(2)O_(3) containing SDS(FOS)without UV light,the final product was bidentate nitrate.SDS was the catalysis agent supply and photoresist to the system.With surface active compounds,the environmental lifetime of heterogeneous reactions between trace gases and aerosols extends.Surfactants,ultraviolet light,and the types of gases involved in the reaction all have complex effects on the aerosol aging process.This study provided a reference for subsequent heterogeneous reaction studies and the formation of aerosols.
基金funded by the National Natural Science Foundation of China and the Machinery Industry Innovation Platform Construction Project of China Machinery Industry Federation,Grant Numbers 52378103 and 2019SA-10-07.
文摘Buildings with large open spaces in which chemicals are handled are often exposed to the risk of explosions.Computational fluid dynamics is a useful and convenient way to investigate contaminant dispersion in such large spaces.The turbulent Schmidt number(Sc_(t))concept has typically been used in this regard,and most studies have adopted a default value.We studied the concentration distribution for sulfur hexafluoride(SF_(6))assuming different emission rates and considering the effect of Sc_(t).Then we examined the same problem for a light gas by assuming hydrogen gas(H_(2))as the contaminant.When SF_(6) was considered as the contaminant gas,a variation in the emission rate completely changed the concentration distribution.When the emission rate was low,the gravitational effect did not take place.For both low and high emission rates,an increase in S_(ct) accelerated the transport rate of SF_(6).In contrast,for H_(2) as the contaminant gas,a larger S_(ct) could induce a decrease in the H_(2) transport rate.
文摘The on-going COVID-19 pandemic has wrecked havoc in our society,with short and long-term consequences to people’s lives and livelihoods-over 651 million COVID-19 cases have been confirmed with the number of deaths exceeding 6.66 million.As people stay indoors most of the time,how to operate the Heating,Ventilation and Air-Conditioning(HVAC)systems as well as building facilities to reduce airborne infections have become hot research topics.This paper presents a systematic review on COVID-19 related research in HVAC systems and the indoor environment.Firstly,it reviews the research on the improvement of ventilation,filtration,heating and air-conditioning systems since the onset of COVID-19.Secondly,various indoor environment improvement measures to minimize airborne spread,such as building envelope design,physical barriers and vent position arrangement,and the possible impact of COVID-19 on building energy consumption are examined.Thirdly,it provides comparisons on the building operation guidelines for preventing the spread of COVID-19 virus from different countries.Finally,recommendations for future studies are provided.
基金supported by the National Natural Science Founda-tion of China (Grant No.41977370)a key project of Jiangsu Provincial Health Commission (ZD2021021).
文摘Outbreaks of airborne infections during meal consumption in diverse restaurant settings have been extensively reported.It is widely recognized that effective ventilation strategies are essential to minimize the infection risk in indoor environments,and these strategies should be tailored to the heat sources.The purpose of this study is to compare the spatial distribution of risk in restaurant rooms that use mixing or displacement ventilation,specif-ically focusing on the heat sources used for different food types,namely hotpot,normal Chinese food,and iced food.Computational Fluid Dynamics(CFD)was employed to assess exposure risk.Our results indicate that the use of low-temperature heat sources can elevate the risk of infection by increasing the local vertical temperature gradient.In comparison to no heat source,the risk increased by 190.9%and 99.6%for displacement and mixing ventilation strategies,respectively.Under mixing ventilation,both low-temperature and no heat sources showed lower infection risks when compared to displacement ventilation.However,displacement ventilation is found to be highly effective in reducing the risk of infection when using a high-temperature heat source,with only 12.3%of the infection risk observed in mixing ventilation.Furthermore,the use of displacement ventilation resulted in a significant reduction in the odors emitted by hotpot,which were instead absorbed by clothes in the mixing ven-tilation scenario.Our findings provide crucial insights into the development of appropriate ventilation strategies for reducing personal exposure to airborne infections in diverse restaurant settings.Specifically,we recommend using displacement ventilation in restaurants that utilize high-temperature heat sources,as it can substantially reduce the risk of infection.
