Objectives To characterize fine particulate matter(PM_(2.5))-bound polycyclic aromatic hydrocarbons(PAHs)emitted from different cooking fumes and their exposure routes and assess their health-associated impact to prov...Objectives To characterize fine particulate matter(PM_(2.5))-bound polycyclic aromatic hydrocarbons(PAHs)emitted from different cooking fumes and their exposure routes and assess their health-associated impact to provide a reference for health risk prevention from PAH exposure across different age and sex groups.Methods Sixteen PM_(2.5)-bound PAHs emitted from 11 cooking styles were analyzed using GC-MS/MS.The health hazards of these PAHs in the Handan City population(stratified by age and sex)were predicted using the incremental lifetime cancer risk(ILCR)model.The respiratory deposition doses(RDDs)of the PAHs in children and adults were calculated using the PM_(2.5)deposition rates in the upper airway,tracheobronchial,and alveolar regions.Results The total concentrations of PM_(2.5)-bound PAHs ranged from 61.10 to 403.80 ng/m3.Regardless of cooking styles,the ILCRtotal values for adults(1.23×10^(-6)to 3.70×10^(-6))and older adults(1.28×10^(-6)to 3.88×10^(-6))exceeded the acceptable limit of 1.00×10^(-6).With increasing age,the ILCRtotal value first declined and then increased,varying substantially among the population groups.Cancer risk exhibited particularly high sensitivity to short exposure to barbecue-derived PAHs under equivalent body weights.Furthermore,barbecue,Sichuan and Hunan cuisine,Chinese cuisine,and Chinese fast food were associated with higher RDDs for both adults and children.Conclusion ILCRtotal values exceeded the acceptable limit for both females and males of adults,with all cooking styles showing a potentially high cancer risk.Our findings serve as an important reference for refining regulatory strategies related to catering emissions and mitigating health risks associated with cooking styles.展开更多
Cooking fumes （CFs） are mixtures of many toxic components, such as aldehydes, heterocyclic amines, polycyclic aromatic hydrocarbons, fat aerosols and particulate matters. CFs exposure has been proven to be associate...Cooking fumes （CFs） are mixtures of many toxic components, such as aldehydes, heterocyclic amines, polycyclic aromatic hydrocarbons, fat aerosols and particulate matters. CFs exposure has been proven to be associated with many diseases. Lung cancer takes the leading place among the diseases being reported caused by CFs exposure. Molecular and biochemical studies have found that CFs exposure may lead to lung cancer by gene damage, formation of reactive oxygen species, blockage of related proteins’ function, and even cell death. However, reviews about the mechanisms of how CFs exposure leads to lung cancer are still lacking. Elucidation of the mechanisms of lung cancer caused by CFs exposure may provide a new insight into the prevention of lung cancer caused by CFs exposure, as well as laying the foundation for the toxicity study of CFs. In this minor review, the mechanisms of how CFs exposure leads to lung cancer were summarized and discussed.展开更多
Tensile strength of concrete were examined on its partial replacement of cement and sand using ground granulated blast furnace and quarry dust.The study examines its behaviour at different dimensions.This is to monito...Tensile strength of concrete were examined on its partial replacement of cement and sand using ground granulated blast furnace and quarry dust.The study examines its behaviour at different dimensions.This is to monitor the variation effect of these parameters on the growth rates of tensile to the optimum curing age.These include non linear conditions of tensile state,non-elastic and its brittle behaviour at all times as it express zero conditions in tension.This means that it has the ability to with stand pull force.It also reflects its weak ability to handle shear stress thus tends to cause deformation in material as it has poor elasticity.The reflection of its brittle influence the rate of tensile behaviour from concrete ductility.These are known to be a material on modern mechanics of concrete.These are also considered as quasi brittle material.This behaviour was reflected as the system considered evaluating the growth rate of tensile strength that replaced cement and sand with these locally sourced addictives.The developed model monitor other reflected influential parameters such as variation of concrete porosity due it compaction in placements,tensile behaviour reflects these effect that subject it to mechanical properties of concrete.The study expressed the reaction of these parameters in the simulation,the evaluation of these affected the details variation of tensile growth rate at different water cement ratios and curing age.The tensile behaviour that was monitored are based on these factors in the study.The derived model were validated with the a researcher results[24],and both parameters developed best fits correlation.The study is imperative because the system expressed the behaviour of tensile strength from concrete at different dimensions.Experts can applied these concept to monitor tensile behaviour considering these parameters in its growth rates.展开更多
Leo and Sam exited and locked the car in a hurry,forgetting to remove the key which was in theignition.Realizing the mistake,Leo asked,“Why don t we get a coat hanger to open it.”“No,that won t work,”answered Sam....Leo and Sam exited and locked the car in a hurry,forgetting to remove the key which was in theignition.Realizing the mistake,Leo asked,“Why don t we get a coat hanger to open it.”“No,that won t work,”answered Sam.“People will think we re trying to break in.”So Leosuggested,“What if we use a pocket knife to cut around the rubber,then stick a finger in and pull展开更多
In order to improve the performance of Al_(2)O_(3)-SiC-C castables for iron trough,samples were prepared using brown corundum,dense corundum,activated alumina micropowder,ball pitch,and silicon as main raw materials,c...In order to improve the performance of Al_(2)O_(3)-SiC-C castables for iron trough,samples were prepared using brown corundum,dense corundum,activated alumina micropowder,ball pitch,and silicon as main raw materials,calcium aluminate cement as the binder.Several kinds of silica fumes(93SiO_(2),96SiO_(2),and 99SiO_(2))with different particle size distributions and chemical composition were added to research the effects on the properties of castables.The results show that the sample with 99SiO_(2) fume has high water requirement for molding,but the bulk density is the lowest,the apparent porosity is the highest,the oxidation resistance is the worst,and the permanent linear change on heating is low after firing at 1 450 ℃ for 3 h.The bulk density and the apparent porosity of the sample with 93SiO_(2) fume or 96SiO_(2) fume are equivalent,the hot modulus of rupture of the sample with 93SiO_(2) fume is the lowest,and the slag resistance of the sample with 96SiO_(2) fume is the best.The comprehensive performance of the sample with 96SiO_(2) fume is the best.展开更多
Asphalt mixtures generate substantial amounts of harmful fumes and particulate matter (PM) during various construction processes, including factory mixing, vehicle transportation, and field paving. Road workers expose...Asphalt mixtures generate substantial amounts of harmful fumes and particulate matter (PM) during various construction processes, including factory mixing, vehicle transportation, and field paving. Road workers exposed to asphalt fumes face potential health hazards, while the emissions also adversely affect the atmospheric environment. Investigation into the determination of asphalt fume components, the impact of exposure, and inhibition strategies have gained significant attention. This paper conducted an analysis based on the publications from 1998 to 2024 on asphalt fumes, elucidating the knowledge landscape of asphalt fume research. The cooperative features, literature classification, and journal sources in the field are systematically examined. Current research focuses on topics such as composition and emission characterization of asphalt fumes, collection and detection of asphalt fumes, exposure to asphalt fumes and their health effects, and sustainable asphalt technologies and emissions control. Additionally, this paper proposes trends in the asphalt fume research field;it outlines future research directions, offering theoretical guidance for studying the impact and inhibition of asphalt fumes.展开更多
The dynamic characteristics of cooking-related particle size distributions in real-world settings are not fully understood.Through a real-world campaign in a naturally-ventilated apartment in the northwest US,this stu...The dynamic characteristics of cooking-related particle size distributions in real-world settings are not fully understood.Through a real-world campaign in a naturally-ventilated apartment in the northwest US,this study investigates the temporal profiles of size-resolved particle number concentrations(PNCs)ranging from 0.3 to 10µm from frying cooking activities.The cooking scenarios included various combinations of window ventilation,venting range hood(VRH)use,and portable air cleaner(PAC)utilization.Following a standardized pan-frying protocol throughout seven scenarios,real-time PNCs of 16-size bins were measured in the kitchen.The PNCs were empirically compared among size bins,periods,and scenarios.The most abundant size ranges of cooking-related particles were 0.3–0.579µm in number(45%–71%of the total)and 2.685–5.182µm in mass(48%–57%of the total).Compared with the scenario without any cooking-fume mitigating measures,keeping the kitchen windows open reduced the mean PNCs during and within 1-h after cooking for PM_(0.3-2.5),PM_(2.5-10),and PM_(0.3-10)by 78%,92%,and 79%,respectively.By contrast,utilizing a VRH during cooking reduced the corresponding levels by 21%,69%,and 25%,respectively.Combined with running the VRH,using a PAC in the kitchen led to additional reductions of 84%,88%,and 84%,respectively.Additionally,the removal efficiencies of the three strategies generally increased with particle sizes.展开更多
Laminated elastomeric bearings used in seismic isolation rely on the mechanical properties of their constituent elastomers to ensure effective performance.However,despite their resistance to temperature fluctuations a...Laminated elastomeric bearings used in seismic isolation rely on the mechanical properties of their constituent elastomers to ensure effective performance.However,despite their resistance to temperature fluctuations and environmental aggressors,silicone elastomers exhibit relatively low stiffness,limiting their direct applicability in seismic isolation.This study investigates the effect of fumed silica as a reinforcing filler to enhance the mechanical properties of laminated silicone elastomeric bearings.Elastomeric samples were fabricated with varying fumed silica proportions and subjected to Shore A hardness,uniaxial tensile,and lap shear tests to assess the influence of filler content.Additionally,quasi-static tests were conducted on reduced-scale bearing prototypes under combined vertical compression and cyclic horizontal shear to evaluate their seismic isolation performance.The results demonstrate that fumed silica reinforcement significantly increases stiffness,as evidenced by higher Shore A hardness values.However,a trade-off was observed in tensile properties,with reductions in tensile strength and elongation at break.Despite this,the equivalent elastic modulus did not show substantial variation up to large deformations,indicating that stiffness is preserved under most working conditions.Lap shear tests showed that fumed silica improves shear resistance,while quasi-static tests revealed inelastic behavior with small increases in equivalent shear coefficients but no substantial loss in damping ratios.These findings suggest that fumed silica reinforcement enhances silicone elastomers’stiffness and shear resistance while maintaining moderate damping properties,making it a promising approach for improving the mechanical performance of elastomeric bearings in seismic isolation applications.展开更多
Lithium-ion batteries are used extensively in civil,military,and aerospace applications because of their high energy and power density.However,in practical applications,these batteries may encounter extreme cases char...Lithium-ion batteries are used extensively in civil,military,and aerospace applications because of their high energy and power density.However,in practical applications,these batteries may encounter extreme cases characterized by transient high impacts,which impose stringent requirements on their safety and reliability.In recent years,the failure mechanism associated with the short-circuiting of lithium-ion-battery separators under high dynamic impacts has been investigated thoroughly.Based on the separator impact failure mechanism,we prepared a porous polymer polyvinylidene fluoride(PVDF)separator by doping gas-phase SiO_(2)(fumed silica)additive.The gas-phase SiO_(2)has a unique three-dimensional cluster structure,which is impact resistant.The impact resistance of the battery separator was tested using a highdynamic-impact system.The voltage drop of the battery with 3%SiO_(2)content was 33.04%of that of the original PVDF battery.Material characterization of the separator was further explored by scanning electron microscope,static compression,and pore-size adsorption tests.The SiO_(2)with a special cluster structure was distributed uniformly on the surface of the separator and embedded in the inner walls of the pores.Under static compression,the current of the SiO_(2)-PVDF separator with 3%content rose at a lower rate than that of the PVDF separator,with a minimum current of 1.04 mA.After adding SiO_(2),the separator pore size increased from 5 to 20 nm.Also,we used COMSOL to conduct impact simulations of different separators.The calculation results showed that the deformation(9.98%)and internal electrode current(0.018 A)of the SiO_(2)-PVDF lithium-ion battery were lower than the deformation(23.09%)and internal electrode current(0.049 A)of the PVDF lithium-ion battery.The SiO_(2)-doped composite polymer separator with a special cluster structure plays a crucial role in enhancing the impact resistance of lithium-ion batteries.展开更多
In this study,a synergistic sulfidation-acid leaching process was proposed to recover valuable metals from gypsum residue and zinc-containing fume.The equilibrium phase composition of the sulfidation reaction and calc...In this study,a synergistic sulfidation-acid leaching process was proposed to recover valuable metals from gypsum residue and zinc-containing fume.The equilibrium phase composition of the sulfidation reaction and calculations of the thermodynamic stability region show that 89.36%Zn,>99%Pb and>99%Cu of gypsum residue and zinc-containing fume can be sulfured to ZnS,PbS and Cu 2 S,under sufficient sulfur partial pressure,low oxygen partial pressure and 400-1000℃.Sulfidation roasting experiments show that the sulfidation rate of Cu,Pb and Zn reach 81.43%,88.25% and 92.31%,respectively,under the roasting conditions of material mass ratio of 30 g:10 g,carbon dosage of 3.75 g,roasting temperature of 800℃ for 3 h.E−pH plots show that ZnS,PbS and Cu_(2)S can be enriched in the leaching residue,under leaching conditions at 25℃,pH<4 and-0.4 V<φ(E)<0.04 V.The leaching experiments showed that the sulfide is retained in the leaching residue,while the leaching rates of Cu,Pb and Zn are 1.94%,2.05% and 1.51%,respectively,under the conditions of 25℃,C_(HCl) of 0.5 mol/L,L/S of 5 mL/g,stirring rate of 300 r/min,and stirring time of 30 min.This study provides a new approach for the synergistic disposal of gypsum residue and zinc containing fume.展开更多
Traditional cement-based slurries are often constrained by excessive cement consumption,prolonged setting times,and limited controllability,which hinder their broader engineering applications.To overcome these challen...Traditional cement-based slurries are often constrained by excessive cement consumption,prolonged setting times,and limited controllability,which hinder their broader engineering applications.To overcome these challenges,this study focuses on optimizing ordinary cement-based slurry through the incorporation of targeted additives and rational adjustment of mix proportions,with the aim of developing a rapid-setting,early-strength cementitious system.In particular,a series of comparative and orthogonal experiments were conducted to systematically examine the evolution of the slurry's macroscopic properties.In addition,the response surface methodology(RSM)was introduced to reveal the interaction mechanisms among key parameters,thereby establishing a quantitative foundation for the precise regulation of slurry performance.The comparative results demonstrate that silica fume significantly outperforms fly ash in enhancing both the rheological and mechanical behavior of the slurry.Regarding fluidity,the average consistency and slump of the silica fume mixture were reduced by 80 mm and 75 mm,respectively,compared with those containing fly ash,indicating more effective control of flowability.In terms of setting and strength development,the silica fume slurry exhibited a setting time up to 9.6 h shorter and a compressive strength up to 3.6 MPa higher under identical mix conditions.These results confirm the clear superiority of silica fume in promoting rapid solidification and early strength gain.展开更多
Soil cement bentonite(SCB)is a common material for constructing vertical cutoff walls to prevent groundwater migration at contaminated industrial sites.However,site contaminants can degrade the durability of the cutof...Soil cement bentonite(SCB)is a common material for constructing vertical cutoff walls to prevent groundwater migration at contaminated industrial sites.However,site contaminants can degrade the durability of the cutoff wall.To enhance its performance,this study developed a silica fume-SCB(SSCB).The macroscopic and microscopic properties of SSCB were assessed by unconfined compressive strength test,variable head permeability test,X-ray diffraction(XRD),scanning electron microscopy(SEM)and nuclear magnetic resonance(NMR)spectroscopy.The correlation between its multi-scale properties was analyzed based on pore characteristics.The results indicate that increasing the silica fume substitution ratio improved SSCB strength,especially in the middle and late curing stages.Moreover,increasing the substitution ratio decreased SSCB permeability coefficient,with a more pronounced effect in earlier curing stages.Silica fume addition also refined SSCB pore structure and reduced its porosity.The fractal dimension was used to quantify SSCB pore structure complexity.Increasing silica fume content reduced small pore fractal dimension in SSCB.Concurrently,SSCB strength increased and SSCB permeability coefficient decreased.The findings of this research will demonstrate the great potential of SSCB backfill for practical applications.展开更多
To mitigate the severe abrasion damage caused by high-velocity water flow in hydraulic engineering applications in Xizang, China, this study systematically optimized key mix design parameters, including aggregate grad...To mitigate the severe abrasion damage caused by high-velocity water flow in hydraulic engineering applications in Xizang, China, this study systematically optimized key mix design parameters, including aggregate gradation, sand ratio, fly ash content, and superplasticizer dosage. Based on the optimized mix, the combined effects of an abrasion-resistance enhancement admixture (AEA) and silica fume (SF) on the abrasion resistance of self-compacting concrete (SCC) were examined. The results demonstrated that the appropriate incorporation of AEA and SF significantly improved the abrasion resistance of SCC without compromising its workability. The proposed mix design not only achieves superior abrasion resistance but also provides practical guidance for the material design and engineering application of durable hydraulic concrete in harsh environments. Future research will focus on comprehensive durability assessments by simulating extreme hydraulic conditions, including sustained exposure to high-velocity sediment-laden flows, repeated freeze-thaw cycles, and corrosive salt spray environments, to thoroughly evaluate the long-term performance evolution of abrasion-resistant self-compacting concrete. Meanwhile, advanced microstructural analytical methods should be applied toelaborate the synergistic mechanisms of abrasion-resistance enhancement admixture (AEA), silica fume (SF), and steel fibers in altering the hydration product formation, optimizing the distribution of pore structure, and strengthening interfacial transition zones, to establish a solid scientific foundation for the development of high-performance composite materials.展开更多
Development of sustainable construction materials has been the focus of research efforts worldwide in recent years.Concrete is a major construction material;hence,finding alternatives to ordinary Portland cement is of...Development of sustainable construction materials has been the focus of research efforts worldwide in recent years.Concrete is a major construction material;hence,finding alternatives to ordinary Portland cement is of extreme importance due to the high levels of carbon dioxide emissions associated with its manufacturing process.This study investigates the geopolymerization process.Specimens with,two different water/binder weight ratios,0.30 and 0.35,were monitored using acoustic emission.Results show that there is a significant difference in the acquisition data between the two different water/binder weight ratios.In addition,acoustic emission can be used to beneficially monitor and investigate the early geopolymerization process.The acoustic emission data were processed through pattern recognition.Two clusters were identified,assigned to a specific mechanism depending on their characteristics.SEM observations were coincided with pattern recognition findings.展开更多
Microwave was applied to roasting the zinc oxide fume obtained from fuming furnace for the removal of F and Cl. The effects of important parameters, such as roasting temperature, holding time and stirring speed, were ...Microwave was applied to roasting the zinc oxide fume obtained from fuming furnace for the removal of F and Cl. The effects of important parameters, such as roasting temperature, holding time and stirring speed, were investigated and the process conditions were optimized using response surface methodology (RSM). The results show that the effects of roasting temperature and holding time on the removal rate of F and Cl are the most significant, and the effect of stirring speed is the second. The defluorination rate reaches 92.6% while the dechlorination rate reaches 90.2%, under the process conditions of roasting temperature of 700 °C, holding time of 80 min and stirring speed of 120 r/min. The results indicate that the removal of F and Cl from fuming furnace production of zinc oxide fumes using microwave roasting process is feasible and reliable.展开更多
Modern China,similar to most developing nations,has seen a rise in the prevalence of both obesity and diesel exhaust based air pollution.The cause of obesity is multi-factorial encompassing diet,lifestyle and social f...Modern China,similar to most developing nations,has seen a rise in the prevalence of both obesity and diesel exhaust based air pollution.The cause of obesity is multi-factorial encompassing diet,lifestyle and social factors.Also there has been a reduction in the consumption of fruit,vegetables,and traditional medicinal foods such as polyphenol containing green tea.Replacing these,are high fat and carbohydrate based processed foods which are quickly displacing these wholefoods in the diet.This review paper proposes evidence that a potential cause of obesity is also linked to environmental stress stimuli such as air pollutants,particularly diesel exhaust fumes(DEF)of>2.5μm particulate matter,and discusses a role for a green tea catechin(EGCG)for use as a dietary defence against diet and environmentally induced obesity.China is now at a critical point of a public health pandemic with rising air-borne pollution(via car exhaust fumes DEF),industry pollution such as heavy metals,and the benzene hydrocarbon based‘2PM’particulate matter,now accepted as a major environmental issue for public health.Relevant data published in MEDLINE since 1995 has been gathered to formulate the following review.展开更多
An adverse effect resulting from explosive mine blasts is the production of toxic nitrogen oxides(NO and NO_(2)) and carbon monoxide(CO).The empirical measurements of the concentration of toxic gases showed that it de...An adverse effect resulting from explosive mine blasts is the production of toxic nitrogen oxides(NO and NO_(2)) and carbon monoxide(CO).The empirical measurements of the concentration of toxic gases showed that it depends not only on the composition of an explosive and properties of its ingredients but also on several other parameters,such as volume of blasting chamber,explosive charge mass and design,confinement characteristics,surrounding atmosphere,etc.That explains why measured concentrations of toxic gases reported in literature significantly differ.In this paper,we discuss the possibility of theoretical prediction of the concentration of toxic gases by thermochemical equilibrium calculation applying two models:ideal detonation model and deflagration model.It can be demonstrated that thermochemical calculations can provide a good estimation of the measured concentrations and reproduce experimentally obtained effects of additives on the production of toxic gases.It was also found that the ideal detonation model applies to heavily confined explosive charges,while the deflagration model is more suitable for low detonation velocity explosives with light confinement.展开更多
There are certification and airworthiness requirements relevant to the provision of clean breathing air in the crew and passenger compartments. There have been continuing reports and studies over the years regarding o...There are certification and airworthiness requirements relevant to the provision of clean breathing air in the crew and passenger compartments. There have been continuing reports and studies over the years regarding oil fumes in aircraft, including impaired crew performance. Oil fumes are viewed in varying ways ranging from rare seal bearing failures, to low level leakage in normal flight. A Masters of Science (MSc) research degree was undertaken to assess whether there is any gap between the certification requirements for the provision of clean air in crew and passenger compartments, and the theoretical and practical implementation of the requirements using the bleed air system. A comprehensive literature search reviewed applicable certification standards, documented and theoretical understanding of oil leakage. Two types of interviews were conducted to address the research questions. Key aviation regulators were questioned about the process by which they certify and ensure compliance with the clean air requirements. Aerospace engineers and sealing professionals were interviewed about their understanding of how oil may leak past compressor oil bearing seals, and into the air supply under various flight conditions. The outcome of the research showed that there is a gap between the clean air certification requirements, and the theoretical and practical implementation of the requirements using the bleed air system. Low level oil leakage into the aircraft cabin in normal flight operations is a function of the design of the engine lubricating system and bleed air systems, both utilising pressurised air. The use of the bleed air system to supply the regulatory required air quality standards is not being met or being enforced as required.展开更多
A laboratory system was designed to generate bitumen fumes and expose tested samplers in a homogenised chamber. The system was also designed to condense the fumes in the form of oil that could be used as a standard fo...A laboratory system was designed to generate bitumen fumes and expose tested samplers in a homogenised chamber. The system was also designed to condense the fumes in the form of oil that could be used as a standard for further analytical method development. The laboratory system was evaluated in terms of stability, repeatability, aging, and ranges, focusing on the quality and quantity of the fumes and their physical characteristics. The fumes generated with the laboratory system were also compared to fumes emitted at workplaces to evaluate their similarity. The results demonstrated that laboratory fume generation was stable and repeatable. Humidity ranged from 20% to 80% RH and the total fume concentration ranged from 0.01 to 9.36 mg.m<sup>-3</sup>, covering the conditions encountered for road paving worksites. The fumes generated in the laboratory were found to be similar to those of workplaces, with slight differences in light compounds equivalent to C12 and below n-alkanes. Thus, the system designed in this study is considered capable of generating bitumen fumes used to develop sampling and analysis methods.展开更多
基金supported by the National Natural Science Foundation of China(No.52330002)the Natural Science Foundation of Beijing Municipality(No.8232020)the First Batch of Key Disciplines on Public Health in Chongqing(YWBF2022072).
文摘Objectives To characterize fine particulate matter(PM_(2.5))-bound polycyclic aromatic hydrocarbons(PAHs)emitted from different cooking fumes and their exposure routes and assess their health-associated impact to provide a reference for health risk prevention from PAH exposure across different age and sex groups.Methods Sixteen PM_(2.5)-bound PAHs emitted from 11 cooking styles were analyzed using GC-MS/MS.The health hazards of these PAHs in the Handan City population(stratified by age and sex)were predicted using the incremental lifetime cancer risk(ILCR)model.The respiratory deposition doses(RDDs)of the PAHs in children and adults were calculated using the PM_(2.5)deposition rates in the upper airway,tracheobronchial,and alveolar regions.Results The total concentrations of PM_(2.5)-bound PAHs ranged from 61.10 to 403.80 ng/m3.Regardless of cooking styles,the ILCRtotal values for adults(1.23×10^(-6)to 3.70×10^(-6))and older adults(1.28×10^(-6)to 3.88×10^(-6))exceeded the acceptable limit of 1.00×10^(-6).With increasing age,the ILCRtotal value first declined and then increased,varying substantially among the population groups.Cancer risk exhibited particularly high sensitivity to short exposure to barbecue-derived PAHs under equivalent body weights.Furthermore,barbecue,Sichuan and Hunan cuisine,Chinese cuisine,and Chinese fast food were associated with higher RDDs for both adults and children.Conclusion ILCRtotal values exceeded the acceptable limit for both females and males of adults,with all cooking styles showing a potentially high cancer risk.Our findings serve as an important reference for refining regulatory strategies related to catering emissions and mitigating health risks associated with cooking styles.
基金Supported by the Development Project of Community Health Nursing Innovative Practice Model of China(CMB08883)
文摘Cooking fumes （CFs） are mixtures of many toxic components, such as aldehydes, heterocyclic amines, polycyclic aromatic hydrocarbons, fat aerosols and particulate matters. CFs exposure has been proven to be associated with many diseases. Lung cancer takes the leading place among the diseases being reported caused by CFs exposure. Molecular and biochemical studies have found that CFs exposure may lead to lung cancer by gene damage, formation of reactive oxygen species, blockage of related proteins’ function, and even cell death. However, reviews about the mechanisms of how CFs exposure leads to lung cancer are still lacking. Elucidation of the mechanisms of lung cancer caused by CFs exposure may provide a new insight into the prevention of lung cancer caused by CFs exposure, as well as laying the foundation for the toxicity study of CFs. In this minor review, the mechanisms of how CFs exposure leads to lung cancer were summarized and discussed.
文摘Tensile strength of concrete were examined on its partial replacement of cement and sand using ground granulated blast furnace and quarry dust.The study examines its behaviour at different dimensions.This is to monitor the variation effect of these parameters on the growth rates of tensile to the optimum curing age.These include non linear conditions of tensile state,non-elastic and its brittle behaviour at all times as it express zero conditions in tension.This means that it has the ability to with stand pull force.It also reflects its weak ability to handle shear stress thus tends to cause deformation in material as it has poor elasticity.The reflection of its brittle influence the rate of tensile behaviour from concrete ductility.These are known to be a material on modern mechanics of concrete.These are also considered as quasi brittle material.This behaviour was reflected as the system considered evaluating the growth rate of tensile strength that replaced cement and sand with these locally sourced addictives.The developed model monitor other reflected influential parameters such as variation of concrete porosity due it compaction in placements,tensile behaviour reflects these effect that subject it to mechanical properties of concrete.The study expressed the reaction of these parameters in the simulation,the evaluation of these affected the details variation of tensile growth rate at different water cement ratios and curing age.The tensile behaviour that was monitored are based on these factors in the study.The derived model were validated with the a researcher results[24],and both parameters developed best fits correlation.The study is imperative because the system expressed the behaviour of tensile strength from concrete at different dimensions.Experts can applied these concept to monitor tensile behaviour considering these parameters in its growth rates.
文摘Leo and Sam exited and locked the car in a hurry,forgetting to remove the key which was in theignition.Realizing the mistake,Leo asked,“Why don t we get a coat hanger to open it.”“No,that won t work,”answered Sam.“People will think we re trying to break in.”So Leosuggested,“What if we use a pocket knife to cut around the rubber,then stick a finger in and pull
文摘In order to improve the performance of Al_(2)O_(3)-SiC-C castables for iron trough,samples were prepared using brown corundum,dense corundum,activated alumina micropowder,ball pitch,and silicon as main raw materials,calcium aluminate cement as the binder.Several kinds of silica fumes(93SiO_(2),96SiO_(2),and 99SiO_(2))with different particle size distributions and chemical composition were added to research the effects on the properties of castables.The results show that the sample with 99SiO_(2) fume has high water requirement for molding,but the bulk density is the lowest,the apparent porosity is the highest,the oxidation resistance is the worst,and the permanent linear change on heating is low after firing at 1 450 ℃ for 3 h.The bulk density and the apparent porosity of the sample with 93SiO_(2) fume or 96SiO_(2) fume are equivalent,the hot modulus of rupture of the sample with 93SiO_(2) fume is the lowest,and the slag resistance of the sample with 96SiO_(2) fume is the best.The comprehensive performance of the sample with 96SiO_(2) fume is the best.
基金supported by the Fundamental Research Funds for the Central Universities,CHD(grant number 300102214702)Scientific Innovation Practice Project of Postgraduates of Chang'an University(grant number 300103725002).
文摘Asphalt mixtures generate substantial amounts of harmful fumes and particulate matter (PM) during various construction processes, including factory mixing, vehicle transportation, and field paving. Road workers exposed to asphalt fumes face potential health hazards, while the emissions also adversely affect the atmospheric environment. Investigation into the determination of asphalt fume components, the impact of exposure, and inhibition strategies have gained significant attention. This paper conducted an analysis based on the publications from 1998 to 2024 on asphalt fumes, elucidating the knowledge landscape of asphalt fume research. The cooperative features, literature classification, and journal sources in the field are systematically examined. Current research focuses on topics such as composition and emission characterization of asphalt fumes, collection and detection of asphalt fumes, exposure to asphalt fumes and their health effects, and sustainable asphalt technologies and emissions control. Additionally, this paper proposes trends in the asphalt fume research field;it outlines future research directions, offering theoretical guidance for studying the impact and inhibition of asphalt fumes.
基金the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(22qntd4308)a special fund of Beijing Key Laboratory of Indoor Air Quality Evaluation and Control(No.BZ0344KF21-05)State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex(No.SCAPC202106).
文摘The dynamic characteristics of cooking-related particle size distributions in real-world settings are not fully understood.Through a real-world campaign in a naturally-ventilated apartment in the northwest US,this study investigates the temporal profiles of size-resolved particle number concentrations(PNCs)ranging from 0.3 to 10µm from frying cooking activities.The cooking scenarios included various combinations of window ventilation,venting range hood(VRH)use,and portable air cleaner(PAC)utilization.Following a standardized pan-frying protocol throughout seven scenarios,real-time PNCs of 16-size bins were measured in the kitchen.The PNCs were empirically compared among size bins,periods,and scenarios.The most abundant size ranges of cooking-related particles were 0.3–0.579µm in number(45%–71%of the total)and 2.685–5.182µm in mass(48%–57%of the total).Compared with the scenario without any cooking-fume mitigating measures,keeping the kitchen windows open reduced the mean PNCs during and within 1-h after cooking for PM_(0.3-2.5),PM_(2.5-10),and PM_(0.3-10)by 78%,92%,and 79%,respectively.By contrast,utilizing a VRH during cooking reduced the corresponding levels by 21%,69%,and 25%,respectively.Combined with running the VRH,using a PAC in the kitchen led to additional reductions of 84%,88%,and 84%,respectively.Additionally,the removal efficiencies of the three strategies generally increased with particle sizes.
文摘Laminated elastomeric bearings used in seismic isolation rely on the mechanical properties of their constituent elastomers to ensure effective performance.However,despite their resistance to temperature fluctuations and environmental aggressors,silicone elastomers exhibit relatively low stiffness,limiting their direct applicability in seismic isolation.This study investigates the effect of fumed silica as a reinforcing filler to enhance the mechanical properties of laminated silicone elastomeric bearings.Elastomeric samples were fabricated with varying fumed silica proportions and subjected to Shore A hardness,uniaxial tensile,and lap shear tests to assess the influence of filler content.Additionally,quasi-static tests were conducted on reduced-scale bearing prototypes under combined vertical compression and cyclic horizontal shear to evaluate their seismic isolation performance.The results demonstrate that fumed silica reinforcement significantly increases stiffness,as evidenced by higher Shore A hardness values.However,a trade-off was observed in tensile properties,with reductions in tensile strength and elongation at break.Despite this,the equivalent elastic modulus did not show substantial variation up to large deformations,indicating that stiffness is preserved under most working conditions.Lap shear tests showed that fumed silica improves shear resistance,while quasi-static tests revealed inelastic behavior with small increases in equivalent shear coefficients but no substantial loss in damping ratios.These findings suggest that fumed silica reinforcement enhances silicone elastomers’stiffness and shear resistance while maintaining moderate damping properties,making it a promising approach for improving the mechanical performance of elastomeric bearings in seismic isolation applications.
基金supported by the Young Elite Scientists Sponsorship Program by CAST(Grant No.2023QNRC001).
文摘Lithium-ion batteries are used extensively in civil,military,and aerospace applications because of their high energy and power density.However,in practical applications,these batteries may encounter extreme cases characterized by transient high impacts,which impose stringent requirements on their safety and reliability.In recent years,the failure mechanism associated with the short-circuiting of lithium-ion-battery separators under high dynamic impacts has been investigated thoroughly.Based on the separator impact failure mechanism,we prepared a porous polymer polyvinylidene fluoride(PVDF)separator by doping gas-phase SiO_(2)(fumed silica)additive.The gas-phase SiO_(2)has a unique three-dimensional cluster structure,which is impact resistant.The impact resistance of the battery separator was tested using a highdynamic-impact system.The voltage drop of the battery with 3%SiO_(2)content was 33.04%of that of the original PVDF battery.Material characterization of the separator was further explored by scanning electron microscope,static compression,and pore-size adsorption tests.The SiO_(2)with a special cluster structure was distributed uniformly on the surface of the separator and embedded in the inner walls of the pores.Under static compression,the current of the SiO_(2)-PVDF separator with 3%content rose at a lower rate than that of the PVDF separator,with a minimum current of 1.04 mA.After adding SiO_(2),the separator pore size increased from 5 to 20 nm.Also,we used COMSOL to conduct impact simulations of different separators.The calculation results showed that the deformation(9.98%)and internal electrode current(0.018 A)of the SiO_(2)-PVDF lithium-ion battery were lower than the deformation(23.09%)and internal electrode current(0.049 A)of the PVDF lithium-ion battery.The SiO_(2)-doped composite polymer separator with a special cluster structure plays a crucial role in enhancing the impact resistance of lithium-ion batteries.
基金Projects(52174269,52374293)supported by the National Natural Science Foundation of ChinaProject(2022RC1123)supported by the Science and Technology Innovation Program of Hunan Province,China。
文摘In this study,a synergistic sulfidation-acid leaching process was proposed to recover valuable metals from gypsum residue and zinc-containing fume.The equilibrium phase composition of the sulfidation reaction and calculations of the thermodynamic stability region show that 89.36%Zn,>99%Pb and>99%Cu of gypsum residue and zinc-containing fume can be sulfured to ZnS,PbS and Cu 2 S,under sufficient sulfur partial pressure,low oxygen partial pressure and 400-1000℃.Sulfidation roasting experiments show that the sulfidation rate of Cu,Pb and Zn reach 81.43%,88.25% and 92.31%,respectively,under the roasting conditions of material mass ratio of 30 g:10 g,carbon dosage of 3.75 g,roasting temperature of 800℃ for 3 h.E−pH plots show that ZnS,PbS and Cu_(2)S can be enriched in the leaching residue,under leaching conditions at 25℃,pH<4 and-0.4 V<φ(E)<0.04 V.The leaching experiments showed that the sulfide is retained in the leaching residue,while the leaching rates of Cu,Pb and Zn are 1.94%,2.05% and 1.51%,respectively,under the conditions of 25℃,C_(HCl) of 0.5 mol/L,L/S of 5 mL/g,stirring rate of 300 r/min,and stirring time of 30 min.This study provides a new approach for the synergistic disposal of gypsum residue and zinc containing fume.
基金the National Natural Science Foundation of China(52278403).
文摘Traditional cement-based slurries are often constrained by excessive cement consumption,prolonged setting times,and limited controllability,which hinder their broader engineering applications.To overcome these challenges,this study focuses on optimizing ordinary cement-based slurry through the incorporation of targeted additives and rational adjustment of mix proportions,with the aim of developing a rapid-setting,early-strength cementitious system.In particular,a series of comparative and orthogonal experiments were conducted to systematically examine the evolution of the slurry's macroscopic properties.In addition,the response surface methodology(RSM)was introduced to reveal the interaction mechanisms among key parameters,thereby establishing a quantitative foundation for the precise regulation of slurry performance.The comparative results demonstrate that silica fume significantly outperforms fly ash in enhancing both the rheological and mechanical behavior of the slurry.Regarding fluidity,the average consistency and slump of the silica fume mixture were reduced by 80 mm and 75 mm,respectively,compared with those containing fly ash,indicating more effective control of flowability.In terms of setting and strength development,the silica fume slurry exhibited a setting time up to 9.6 h shorter and a compressive strength up to 3.6 MPa higher under identical mix conditions.These results confirm the clear superiority of silica fume in promoting rapid solidification and early strength gain.
基金Project(2019YFC1803601)supported by the National Key Research and Development Program of ChinaProject(52274182)supported by the National Natural Science Foundation of China+1 种基金Project(2021zzts0274)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(CX20210295)supported by the Postgraduate Scientific Research Innovation Project of Hunan Province,China。
文摘Soil cement bentonite(SCB)is a common material for constructing vertical cutoff walls to prevent groundwater migration at contaminated industrial sites.However,site contaminants can degrade the durability of the cutoff wall.To enhance its performance,this study developed a silica fume-SCB(SSCB).The macroscopic and microscopic properties of SSCB were assessed by unconfined compressive strength test,variable head permeability test,X-ray diffraction(XRD),scanning electron microscopy(SEM)and nuclear magnetic resonance(NMR)spectroscopy.The correlation between its multi-scale properties was analyzed based on pore characteristics.The results indicate that increasing the silica fume substitution ratio improved SSCB strength,especially in the middle and late curing stages.Moreover,increasing the substitution ratio decreased SSCB permeability coefficient,with a more pronounced effect in earlier curing stages.Silica fume addition also refined SSCB pore structure and reduced its porosity.The fractal dimension was used to quantify SSCB pore structure complexity.Increasing silica fume content reduced small pore fractal dimension in SSCB.Concurrently,SSCB strength increased and SSCB permeability coefficient decreased.The findings of this research will demonstrate the great potential of SSCB backfill for practical applications.
基金supported by the National Natural Science Foundation of China(No.52179137).
文摘To mitigate the severe abrasion damage caused by high-velocity water flow in hydraulic engineering applications in Xizang, China, this study systematically optimized key mix design parameters, including aggregate gradation, sand ratio, fly ash content, and superplasticizer dosage. Based on the optimized mix, the combined effects of an abrasion-resistance enhancement admixture (AEA) and silica fume (SF) on the abrasion resistance of self-compacting concrete (SCC) were examined. The results demonstrated that the appropriate incorporation of AEA and SF significantly improved the abrasion resistance of SCC without compromising its workability. The proposed mix design not only achieves superior abrasion resistance but also provides practical guidance for the material design and engineering application of durable hydraulic concrete in harsh environments. Future research will focus on comprehensive durability assessments by simulating extreme hydraulic conditions, including sustained exposure to high-velocity sediment-laden flows, repeated freeze-thaw cycles, and corrosive salt spray environments, to thoroughly evaluate the long-term performance evolution of abrasion-resistant self-compacting concrete. Meanwhile, advanced microstructural analytical methods should be applied toelaborate the synergistic mechanisms of abrasion-resistance enhancement admixture (AEA), silica fume (SF), and steel fibers in altering the hydration product formation, optimizing the distribution of pore structure, and strengthening interfacial transition zones, to establish a solid scientific foundation for the development of high-performance composite materials.
基金supported by the U.S.Department of Energy Office of Science,Office of Basic Energy Sciences,and Office of Biological and Environmental Research under Award Number DE-SC-00012530.
文摘Development of sustainable construction materials has been the focus of research efforts worldwide in recent years.Concrete is a major construction material;hence,finding alternatives to ordinary Portland cement is of extreme importance due to the high levels of carbon dioxide emissions associated with its manufacturing process.This study investigates the geopolymerization process.Specimens with,two different water/binder weight ratios,0.30 and 0.35,were monitored using acoustic emission.Results show that there is a significant difference in the acquisition data between the two different water/binder weight ratios.In addition,acoustic emission can be used to beneficially monitor and investigate the early geopolymerization process.The acoustic emission data were processed through pattern recognition.Two clusters were identified,assigned to a specific mechanism depending on their characteristics.SEM observations were coincided with pattern recognition findings.
基金Project(51104073)supported by the National Natural Science Foundation of ChinaProject(2013AA064003)supported by the High-tech Research and Development Program of China+1 种基金Project(2014CB643404)supported by the National Basic Research Program of ChinaProject(2012HB008)supported by Yunnan Province Young Academic Technology Leader Reserve Talents,China
文摘Microwave was applied to roasting the zinc oxide fume obtained from fuming furnace for the removal of F and Cl. The effects of important parameters, such as roasting temperature, holding time and stirring speed, were investigated and the process conditions were optimized using response surface methodology (RSM). The results show that the effects of roasting temperature and holding time on the removal rate of F and Cl are the most significant, and the effect of stirring speed is the second. The defluorination rate reaches 92.6% while the dechlorination rate reaches 90.2%, under the process conditions of roasting temperature of 700 °C, holding time of 80 min and stirring speed of 120 r/min. The results indicate that the removal of F and Cl from fuming furnace production of zinc oxide fumes using microwave roasting process is feasible and reliable.
文摘Modern China,similar to most developing nations,has seen a rise in the prevalence of both obesity and diesel exhaust based air pollution.The cause of obesity is multi-factorial encompassing diet,lifestyle and social factors.Also there has been a reduction in the consumption of fruit,vegetables,and traditional medicinal foods such as polyphenol containing green tea.Replacing these,are high fat and carbohydrate based processed foods which are quickly displacing these wholefoods in the diet.This review paper proposes evidence that a potential cause of obesity is also linked to environmental stress stimuli such as air pollutants,particularly diesel exhaust fumes(DEF)of>2.5μm particulate matter,and discusses a role for a green tea catechin(EGCG)for use as a dietary defence against diet and environmentally induced obesity.China is now at a critical point of a public health pandemic with rising air-borne pollution(via car exhaust fumes DEF),industry pollution such as heavy metals,and the benzene hydrocarbon based‘2PM’particulate matter,now accepted as a major environmental issue for public health.Relevant data published in MEDLINE since 1995 has been gathered to formulate the following review.
基金This research was supported by the Croatian Science Foundation(HRZZ),Croatia,under the projects IP-2019-04-1618“NEIDEMO”.
文摘An adverse effect resulting from explosive mine blasts is the production of toxic nitrogen oxides(NO and NO_(2)) and carbon monoxide(CO).The empirical measurements of the concentration of toxic gases showed that it depends not only on the composition of an explosive and properties of its ingredients but also on several other parameters,such as volume of blasting chamber,explosive charge mass and design,confinement characteristics,surrounding atmosphere,etc.That explains why measured concentrations of toxic gases reported in literature significantly differ.In this paper,we discuss the possibility of theoretical prediction of the concentration of toxic gases by thermochemical equilibrium calculation applying two models:ideal detonation model and deflagration model.It can be demonstrated that thermochemical calculations can provide a good estimation of the measured concentrations and reproduce experimentally obtained effects of additives on the production of toxic gases.It was also found that the ideal detonation model applies to heavily confined explosive charges,while the deflagration model is more suitable for low detonation velocity explosives with light confinement.
文摘There are certification and airworthiness requirements relevant to the provision of clean breathing air in the crew and passenger compartments. There have been continuing reports and studies over the years regarding oil fumes in aircraft, including impaired crew performance. Oil fumes are viewed in varying ways ranging from rare seal bearing failures, to low level leakage in normal flight. A Masters of Science (MSc) research degree was undertaken to assess whether there is any gap between the certification requirements for the provision of clean air in crew and passenger compartments, and the theoretical and practical implementation of the requirements using the bleed air system. A comprehensive literature search reviewed applicable certification standards, documented and theoretical understanding of oil leakage. Two types of interviews were conducted to address the research questions. Key aviation regulators were questioned about the process by which they certify and ensure compliance with the clean air requirements. Aerospace engineers and sealing professionals were interviewed about their understanding of how oil may leak past compressor oil bearing seals, and into the air supply under various flight conditions. The outcome of the research showed that there is a gap between the clean air certification requirements, and the theoretical and practical implementation of the requirements using the bleed air system. Low level oil leakage into the aircraft cabin in normal flight operations is a function of the design of the engine lubricating system and bleed air systems, both utilising pressurised air. The use of the bleed air system to supply the regulatory required air quality standards is not being met or being enforced as required.
文摘A laboratory system was designed to generate bitumen fumes and expose tested samplers in a homogenised chamber. The system was also designed to condense the fumes in the form of oil that could be used as a standard for further analytical method development. The laboratory system was evaluated in terms of stability, repeatability, aging, and ranges, focusing on the quality and quantity of the fumes and their physical characteristics. The fumes generated with the laboratory system were also compared to fumes emitted at workplaces to evaluate their similarity. The results demonstrated that laboratory fume generation was stable and repeatable. Humidity ranged from 20% to 80% RH and the total fume concentration ranged from 0.01 to 9.36 mg.m<sup>-3</sup>, covering the conditions encountered for road paving worksites. The fumes generated in the laboratory were found to be similar to those of workplaces, with slight differences in light compounds equivalent to C12 and below n-alkanes. Thus, the system designed in this study is considered capable of generating bitumen fumes used to develop sampling and analysis methods.
