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
In the present research, effect of silica fume as an additive and oil polluted sands as aggregates on compressive strength of concrete were investigated experimentally. The amount ofoil in the designed mixtures was as...In the present research, effect of silica fume as an additive and oil polluted sands as aggregates on compressive strength of concrete were investigated experimentally. The amount ofoil in the designed mixtures was assumed to be constant and equal to 2% of the sand weight. Silica fume accounting for 10%, 15% and 20% of the weight is added to the designed mixture. After preparation and curing, concrete specimens were placed into the three different conditions： fresh, brackish and saltwater environments （submerged in fresh water, alternation of exposed in air ＆ submerged in sea water and submerged in sea water）. The result of compressive strength tests shows that the compressive strength of the specimens consisting of silica fume increases significantly in comparison with the control specimens in all three environments. The compressive strength of the concrete with 15% silica fume content was about 30% to 50% higher than that of control specimens in all tested environments under the condition of using polluted aggregates in the designed mixture.展开更多
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.
基金the support of the Chabahar Maritime University for supporting this program and usage concrete laboratory of Civil Engineering Department
文摘In the present research, effect of silica fume as an additive and oil polluted sands as aggregates on compressive strength of concrete were investigated experimentally. The amount ofoil in the designed mixtures was assumed to be constant and equal to 2% of the sand weight. Silica fume accounting for 10%, 15% and 20% of the weight is added to the designed mixture. After preparation and curing, concrete specimens were placed into the three different conditions： fresh, brackish and saltwater environments （submerged in fresh water, alternation of exposed in air ＆ submerged in sea water and submerged in sea water）. The result of compressive strength tests shows that the compressive strength of the specimens consisting of silica fume increases significantly in comparison with the control specimens in all three environments. The compressive strength of the concrete with 15% silica fume content was about 30% to 50% higher than that of control specimens in all tested environments under the condition of using polluted aggregates in the designed mixture.
