The release of mercury from intertidal sediment to atmosphere was studied based on the simulated experiment. The experiment samples were collected from the Haibo Estuary (S1) and the Licun Estuary (S2) of the Jiaozhou...The release of mercury from intertidal sediment to atmosphere was studied based on the simulated experiment. The experiment samples were collected from the Haibo Estuary (S1) and the Licun Estuary (S2) of the Jiaozhou Bay in China,which are seriously polluted with mercury. The results show that the mercury in sediment releases rapidly to atmosphere under solar radiation. After 8 hours of solar radiation,mercury concentrations decrease from 5.62 μg/g and 2.92 μg/g to 2.34 μg/g and 1.39 μg/g in S1 and S2 sediments respectively in summer,and decrease from 5.62 μg/g and 2.92 μg/g to 4.58 μg/g and 2.13 μg/g respectively in winter. The mercury species in the sediment change markedly under solar radiation. The concentrations of mercury bound to organic matter decrease significantly from 2.73 μg/g to 0.31 μg/g in S1 and from 2.07 μg/g to 0.31 μg/g in S2,and the released mercury mainly comes from mercury bound to organic matter. Mercury flux shows distinguishing characteristic of diurnal change,and it increases rapidly in the morning with the rising of solar radiation intensity,but decreases in the afternoon. The mercury flux increases with sediment temperature and solar radiation intensity. The rapid release of mercury in intertidal sediment plays an important role in the regional mercury cycle.展开更多
This paper presents study of the effects of urban morphology changes on ventilation dynamics through a comparative study between blocks of Copacabana and Ipanema neighborhoods, located in Rio de Janciro City, Brazil. ...This paper presents study of the effects of urban morphology changes on ventilation dynamics through a comparative study between blocks of Copacabana and Ipanema neighborhoods, located in Rio de Janciro City, Brazil. The study was developed with the aid of experimental simulations in a wind tunnel, taking into account the urban morphology and its relations to open spaces. A diagnosis was produced through the exam of the wind effects in relation to the volume of built and non-built spaces. The effects were classified as positive or negative, in relation to the tropical climate. At first, both blocks studied, one in Ipanema and one in Copacabana, were selected according to common characteristics, which establish a relation between the two regions, such as the distance to the beach and the presence of a public square. The results confirmed our expectations showing Ipanema as a more ventilated area.展开更多
Low energy gamma radiation （0.2-10.0） MeV near the Earth＇s surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons （〉 1 GeV） in terrestrial atmosphere a...Low energy gamma radiation （0.2-10.0） MeV near the Earth＇s surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons （〉 1 GeV） in terrestrial atmosphere are the main sources. The second most important source near the surface of the Earth and in the tropical and equatorial regions is the radon gas （Rn-222） that decays in alpha particles and gamma rays in this energy range. Also the telluric radionuclides 238U, 235U, 40K and 232Th in decays produce gamma radiation with different intensities at different locations on the surface of the Earth. Other sources less present are electrical discharges （lightning strikes） and man-made radioactive sources for medical, dental and industrial applications. In this work, it is shown that measurements of these components during all year 2016 are carried out at the ITA （Technological Institute of Aeronautics） campus in Sao Jose dos Campos, SP, Brazil and their possible correlations with atmospheric phenomena.展开更多
基金Under the auspices of National Natural Science Foundation of China (No. 40806045)the Program of the State Bureau of Oceanic Administration (No. 908-02-02-03)
文摘The release of mercury from intertidal sediment to atmosphere was studied based on the simulated experiment. The experiment samples were collected from the Haibo Estuary (S1) and the Licun Estuary (S2) of the Jiaozhou Bay in China,which are seriously polluted with mercury. The results show that the mercury in sediment releases rapidly to atmosphere under solar radiation. After 8 hours of solar radiation,mercury concentrations decrease from 5.62 μg/g and 2.92 μg/g to 2.34 μg/g and 1.39 μg/g in S1 and S2 sediments respectively in summer,and decrease from 5.62 μg/g and 2.92 μg/g to 4.58 μg/g and 2.13 μg/g respectively in winter. The mercury species in the sediment change markedly under solar radiation. The concentrations of mercury bound to organic matter decrease significantly from 2.73 μg/g to 0.31 μg/g in S1 and from 2.07 μg/g to 0.31 μg/g in S2,and the released mercury mainly comes from mercury bound to organic matter. Mercury flux shows distinguishing characteristic of diurnal change,and it increases rapidly in the morning with the rising of solar radiation intensity,but decreases in the afternoon. The mercury flux increases with sediment temperature and solar radiation intensity. The rapid release of mercury in intertidal sediment plays an important role in the regional mercury cycle.
文摘This paper presents study of the effects of urban morphology changes on ventilation dynamics through a comparative study between blocks of Copacabana and Ipanema neighborhoods, located in Rio de Janciro City, Brazil. The study was developed with the aid of experimental simulations in a wind tunnel, taking into account the urban morphology and its relations to open spaces. A diagnosis was produced through the exam of the wind effects in relation to the volume of built and non-built spaces. The effects were classified as positive or negative, in relation to the tropical climate. At first, both blocks studied, one in Ipanema and one in Copacabana, were selected according to common characteristics, which establish a relation between the two regions, such as the distance to the beach and the presence of a public square. The results confirmed our expectations showing Ipanema as a more ventilated area.
文摘Low energy gamma radiation （0.2-10.0） MeV near the Earth＇s surface has several origins. Primary and secondary cosmic radiations with interactions of very high energy protons （〉 1 GeV） in terrestrial atmosphere are the main sources. The second most important source near the surface of the Earth and in the tropical and equatorial regions is the radon gas （Rn-222） that decays in alpha particles and gamma rays in this energy range. Also the telluric radionuclides 238U, 235U, 40K and 232Th in decays produce gamma radiation with different intensities at different locations on the surface of the Earth. Other sources less present are electrical discharges （lightning strikes） and man-made radioactive sources for medical, dental and industrial applications. In this work, it is shown that measurements of these components during all year 2016 are carried out at the ITA （Technological Institute of Aeronautics） campus in Sao Jose dos Campos, SP, Brazil and their possible correlations with atmospheric phenomena.
