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- Eriksson, Ola, et al.
(författare)
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Municipal Solid Waste Management from a Systems Perspective
- 2005
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Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526 .- 1879-1786. ; 13:3, s. 241-252
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Tidskriftsartikel (refereegranskat)abstract
- Different waste treatment options for municipal solid waste have been studied in a systems analysis. Different combinations of incineration, materials recycling of separated plastic and cardboard containers, and biological treatment (anaerobic digestion and composting) of biodegradable waste, were studied and compared to landfilling. The evaluation covered use of energy resources, environmental impact and financial and environmental costs. In the study, a calculation model ( ) based on methodology from life cycle assessment (LCA) was used. Case studies were performed in three Swedish municipalities: Uppsala, Stockholm, and Älvdalen. The study shows that reduced landfilling in favour of increased recycling of energy and materials lead to lower environmental impact, lower consumption of energy resources, and lower economic costs. Landfilling of energy-rich waste should be avoided as far as possible, partly because of the negative environmental impacts from landfilling, but mainly because of the low recovery of resources when landfilling. Differences between materials recycling, nutrient recycling and incineration are small but in general recycling of plastic is somewhat better than incineration and biological treatment somewhat worse. When planning waste management, it is important to know that the choice of waste treatment method affects processes outside the waste management system, such as generation of district heating, electricity, vehicle fuel, plastic, cardboard, and fertiliser.
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- Sundqvist, J. O., et al.
(författare)
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MgI emission lines at 12 and 18 mu m in K giants
- 2008
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 486:3, s. 985-993
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Tidskriftsartikel (refereegranskat)abstract
- Context. The solar mid-infrared metallic emission lines have already been observed and analyzed well, and the formation scenario of the Mg I 12 mu m lines has been known for more than a decade. Detections of stellar emission at 12 mu m have, however, been limited to Mg I in very few objects. Previous modeling attempts have been made only for Procyon and two cool evolved stars, with unsatisfactory results for the latter. This prevents the lines' long predicted usage as probes of stellar magnetic fields. Aims. We want to explain our observed Mg I emission lines at 12 mu m in the K giants Pollux, Arcturus, and Aldebaran and at 18 mu m in Pollux and Arcturus. We discuss our modeling of these lines and particularly how various aspects of the model atom affect the emergent line profiles. Methods. High-resolution observational spectra were obtained using TEXES at Gemini North and the IRTF. To produce synthetic line spectra, we employed standard one-dimensional, plane-parallel, non-LTE modeling for trace elements in cool stellar atmospheres. We computed model atmospheres with the MARCS code, applied a comprehensive magnesium model atom, and used the radiative transfer code MULTI to solve for the magnesium occupation numbers in statistical equilibrium. Results. The Mg I emission lines at 12 mu m in the K giants are stronger than in the dwarfs observed so far. We present the first observed stellar emission lines from Mg I at 18 mu m and from Al I, Si I, and presumably Ca I at 12 mu m. We successfully reproduce the observed Mg I emission lines simultaneously in the giants and in the Sun, but show how the computed line profiles depend critically on atomic data input and how the inclusion of energy levels with n > ;= 10 and collisions with neutral hydrogen are necessary to obtain reasonable fits.
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- Talyzin, Alexandr, et al.
(författare)
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Reaction of hydrogen gas with C60 at elevated pressure and temperature: Hydrogenation and cage fragmentation.
- 2006
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Ingår i: Journal of Physical Chemistry A. - : American Chemical Society (ACS). - 1089-5639 .- 1520-5215. ; 110:27, s. 8528-34
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Tidskriftsartikel (refereegranskat)abstract
- Products of the reaction of C60 with H2 gas have been monitored by high-resolution atmospheric pressurephotoionization Fourier transform ion cyclotron resonance mass spectrometry (APPI FT-ICR MS), X-raydiffraction, and IR spectroscopy as a function of hydrogenation period. Samples were synthesized at 673 Kand 120 bar hydrogen pressure for hydrogenation periods between 300 and 5000 min, resulting in the formationof hydrofullerene mixtures with hydrogen content ranging from 1.6 to 5.3 wt %. Highly reduced C60Hx (x >36-40) and products of their fragmentation were identified in these samples by APPI FT-ICR MS. A sharpchange in structure was observed for samples with at least 5.0 wt % of hydrogen. Low-mass (300-500 Da)hydrogenation products not observed by prior field desorption (FD) FT-ICR MS were detected by APPIFT-ICR MS and their elemental compositions obtained for the first time. Synthetic and analytical fragmentationpathways are discussed.
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