Results 1 - 10 of 607
Results 1 - 10 of 607. Search took: 0.022 seconds
|Sort by: date | relevance|
[en] We present molecular line and 1.4 mm continuum observations toward five massive star-forming regions at arcsecond resolution using the Submillimeter Array. We find that the warm molecular gas surrounding each H II region (as traced by SO2 and OCS) appears to be undergoing bulk rotation. From the molecular line emission and thermal component of the continuum emission, we independently derived gas masses for each region which are consistent with each other. From the free-free component of the continuum emission, we estimate the minimum stellar mass required to power the H II region and find that this mass, when added to the derived gas mass, is a significant fraction of the dynamical mass for that region.
[en] The ionization spectrum of sulfur dioxide has been successfully studied by using the symmetry-adapted-cluster configuration-interaction (SAC-CI) general-R and SD-R methods and the basis set correlation-consistent polarized valence triple-zeta (cc-pVTZ). The SAC-CI general-R method reproduces the experimental spectrum well for both the main peaks and the satellite peaks of ionization spectrum of SO2. The sequence of ionic states corresponding to main peaks of SO2 has been re-determined according to the SAC-CI conclusions and it is reordered as X-bar 2A1, Ã2B2, B-bar 2A2, C-bar 2B1, D-bar 2A1, Ē2B2 and F-bar 2A1. Besides, the equilibrium structures and adiabatic ionization potentials (AIPs) of ionic states of main peaks of SO2 are calculated by using the SAC-CI SD-R method. (atomic and molecular physics)
[en] 05B is a strain of iron-oxidizing bacterium which separated from a uranium ore. The effect of temperature, initial pH, inoculation amount and initial total iron concentration on the strain's growth and activities in bioleaching of uranium ores are studied. The results show that the optimum growth temperature is 40-45 degree C, the optimum inoculation pH value being 1.5-1.7, the optimum initial inoculation amount being 10%-20%, and the initial total iron concentration being not more than 5 g/L. 05B is fit for leaching of low grade uranium ores. (authors)
[en] In this paper, we first add to what is a growing literature on the existence and nature of the environmental Kuznets curve (EKC) model for developing countries, by testing for the existence of an EKC for China using a panel data set of city-specific, annual ambient levels of SO2 pollution. We find some support for both the typical inverted-U-shaped relationship and an N-shaped, cubic configuration. More significantly, we then explore the possibility of China's 'tunneling' through the EKC, by using newer, cleaner technologies, and thereby avoiding some of the environmental degradation that had often accompanied economic growth. Specifically, we estimate and economically value the health benefits realizable to Chinese cities from successful efforts to 'tunnel' under the EKC over the next generation. (author)
[en] Sulfur dioxide (SO2) and nitrogen oxides (NOX) are major air pollutants. Before emitting flue gas into the atmosphere, these pollutants must be removed using various processes. A sol-gel process has been developed to prepare alumina granular support and catalyst. The sol-gel-derived alumina granules have a large surface area, large pore volume, uniform pore size distribution, and excellent mechanical properties such as attrition resistance and crush strength. This paper discussed an experiment that synthesized two catalysts using the sol-gel oil-drop method. The paper described the experimental procedure and presented the results of the experiment. This included the effect of temperature on the catalytic activity of CuO-CeO2-MnOx/y-Al2O3 catalysts; desorption of ammonia (NH3) and nitric oxide (NO) on the CuO-CeO2-MnOx/y-Al2O3 catalysts; transient response of NH3 and NO on CuO-CeO2-MnOx/y-Al2O3 catalysts; and the reaction kinetics and characterization of CuO-CeO2-MnOx/y-Al2O3 catalysts. It was concluded that the CuO-CeO2-MnOx/y-Al2O3 catalysts made by the sol-gel method have higher activity and a wider operating temperature range. 17 refs., 1 tab., 9 figs
[en] Hydrogen can be an attractive energy if it can be produced cleanly and in a cost effective manner. Nuclear energy can be used as a source of a high temperature process up to 1000 for a hydrogen production. The sulfur-iodine (SI) cycle is a baseline candidate thermo-chemical process. It consists of the following three chemical reactions which yield a dissociation of water. The decomposition at a high temperature of the sulfuric acid is the most energy-demanding reaction both from fundamental and applied points of views which represents the key reaction of the whole SI cycle. In this paper, a shell-and-catalyst-packed-tube type is selected and its fluidic characteristics are applied to an overall heat transfer coefficient calculation. As a result of the study, the sulfur trioxide decomposers for 300mole/s (200MWth VHTR 40% thermal efficiency) and 60mole/s (40MWth VHTR 40% thermal efficiency) hydrogen production rates are presented and discussed
[en] Dielectric barrier discharge (DBD) for SO2 removal from indoor air is investigated. In order to improve the removal efficiency, two novel methods are combined in this paper, namely by applying a pulsed driving voltage with nanosecond rising time and applying a magnetic field. For SO2 removal efficiency, different matches of electric field and magnetic field are discussed. And nanosecond rising edge pulsed power supply and microsecond rising edge pulsed power supply are compared. It can be concluded that a pulsed DBD with nanosecond rising edge should be adopted, and electrical field and magnetic field should be applied in an appropriate match
[en] A collection of 50 indigenous meta-toluate tolerating bacteria isolated from oil-contaminated rhizosphere of Galega orientalis on selective medium was characterized and identified by classical and molecular methods. 16S rDNA partial sequencing showed the presence of five major lineages of the Bacteria domain. Gram-positive Rhodococcus, Bacillus and Arthrobacter and gram-negative Pseudomonas were the most abundant genera. Only one-fifth of the strains that tolerated m-toluate also degraded m-toluate. The inoculum Pseudomonas putida PaW85 was not found in the rhizosphere samples. The ability to degrade m-toluate by the TOL plasmid was detected only in species of the genus Pseudomonas. However, a few Rhodococcus erythropolis strains were found which were able to degrade m-toluate. A new finding was that Pseudomonas migulae strains and a few P. oryzihabitans strains were able to grow on m-toluate and most likely contained the TOL plasmid. Because strain specific differences in degradation abilities were found for P. oryzihabitans, separation at the strain level was important. For strain specific separation (GTG)5 fingerprinting was the best method. A combination of the single locus ribotyping and the whole genomic fingerprinting techniques with the selective partial sequencing formed a practical molecular toolbox for studying genetic diversity of culturable bacteria in oil-contaminated rhizosphere. - Bacterial diversity during rhizoremediation in oil-contaminated soil is characterized by a combination of molecular methods
[en] We theoretically analyze the effectiveness of multiple-pulse laser alignment methods for asymmetric-top molecules. As an example, we choose SO2 and investigate the alignment dynamics induced by two different sequences, each consisting of four identical laser pulses. Each sequence differs only in the time delay between the pulses. Equally spaced pulses matching the alignment revival of the symmetrized SO2 rotor model are exploited in the first sequence. The pulse separations in the second sequence are short compared to the rotation dynamics of the molecule and monotonically increase the degree of alignment until the maximum alignment is reached. We point out the significant differences between the alignment dynamics of SO2 treated as an asymmetric-top and a symmetric-top rotor, respectively. We also explain why the fast sequence of laser pulses creates considerably stronger one-dimensional molecular alignment for asymmetric-top molecules. In addition, we show that multiple-pulse trains with elliptically polarized pulses do not enhance one-dimensional alignment or create three-dimensional alignment.
[en] The emission parameters and expose-response functions of some pollutants, such as sulphur dioxide (SO2) and Inhalable Particulate Matter (PM10), were introduced to calculate the emission caused by energy consumption in various sectors and regions in China under different scenarios. The impacts of economic growth, population, and technology progress on energy consumption and on the environment were also analyzed. Finally, the economic value of public health damage caused by the changes of pollutants' concentration related to energy consumption under various scenarios, different regions and sectors in China was analyzed. The results show that the PM-10 and SO2 emissions and consequent health damage will increase significantly in the next 12 years. Thus, energy efficiency, population, economy, and urbanization are the main factors to be considered in this system. (author)